U.S. patent application number 14/348194 was filed with the patent office on 2015-03-12 for sperm staining and sorting methods.
This patent application is currently assigned to INGURAN, LLC. The applicant listed for this patent is INGURAN, LLC. Invention is credited to Kenneth Michael Evans, Thomas B. Gilligan, Clara Gonzalez-Marin.
Application Number | 20150072340 14/348194 |
Document ID | / |
Family ID | 47046868 |
Filed Date | 2015-03-12 |
United States Patent
Application |
20150072340 |
Kind Code |
A2 |
Evans; Kenneth Michael ; et
al. |
March 12, 2015 |
SPERM STAINING AND SORTING METHODS
Abstract
A method of sex sorting sperm is disclosed. The sperm may be
stained with a DNA selective fluorescent dye, which fluoresces when
excited, a dead quenching dye, which selectively quenches
fluorescence emitted by the DNA selective fluorescent dye within
the membrane of compromised sperm, and a split enhancing dye. The
stained sperm may then sorted into one or more gender enriched
subpopulations of viable sperm.
Inventors: |
Evans; Kenneth Michael;
(College Station, TX) ; Gilligan; Thomas B.;
(College Station, TX) ; Gonzalez-Marin; Clara;
(College Station, TX) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
INGURAN, LLC |
Navasota |
TX |
US |
|
|
Assignee: |
INGURAN, LLC
Navasota
TX
|
Prior
Publication: |
|
Document Identifier |
Publication Date |
|
US 20140234833 A1 |
August 21, 2014 |
|
|
Family ID: |
47046868 |
Appl. No.: |
14/348194 |
Filed: |
September 28, 2012 |
PCT Filed: |
September 28, 2012 |
PCT NO: |
PCT/US2012/058008 PCKC 00 |
371 Date: |
March 28, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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61541438 |
Sep 30, 2011 |
|
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61541451 |
Sep 30, 2011 |
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Current U.S.
Class: |
435/6.1 ;
435/374 |
Current CPC
Class: |
G01N 2021/6441 20130101;
G01N 33/5005 20130101; G01N 21/6428 20130101; C12N 5/061 20130101;
G01N 2021/6432 20130101 |
Class at
Publication: |
435/6.1 ;
435/374 |
International
Class: |
G01N 33/50 20060101
G01N033/50; C12N 5/076 20060101 C12N005/076 |
Claims
1-35. (canceled)
36. A method of gender enriching one or more sperm subpopulations
comprising the steps of: a. obtaining a population of sperm
including X-chromosome bearing sperm and Y-chromosome bearing
sperm; b. staining at least a portion of the population of sperm
with a DNA selective fluorescent dye which fluoresces when excited;
c. staining said portion of the population of sperm with a dead
quenching dye for selectively quenching fluorescence emitted by the
DNA selective fluorescent dye in membrane compromised sperm,
wherein the dead quenching dye is a yellow dye, an orange dye or an
orangish-red dye; and d. sorting the stained sperm into one or more
gender enriched subpopulations of viable sperm.
37. The method of claim 36 wherein the absorption maximum of the
dead quenching dye is matched with the excitation maximum of the
DNA selective fluorescent dye.
38. The method of claim 36 wherein the dead quenching dye is
selected for having absorption maxima at wavelengths between about
420 nm and about 500 nm.
39. The method of claim 36 wherein the dead quenching dye is a food
dye.
40. The method of claim 36 wherein the dead quenching dye is
selected from yellow food dye No. 6, yellow food dye No. 5, red
food dye No. 4, and combinations thereof.
41. The method of claim 36 wherein the dead quenching dye comprises
yellow food dye No. 6.
42. The method of claim 36 wherein the selection of a yellow food
dye as the dead quenching dye allows for staining with a lower
concentration of the DNA selective fluorescent dye as when compared
to red food dye no. 40 as the dead quenching dye.
43. The method of claim 36 wherein the dead quenching dye
differentially permeates membrane compromised sperm so that
unquenched sperm are enriched with respect to sperm viability
compared to the population of sperm.
44. The method of claim 36 wherein the dead quenching dye
differentially permeates membrane compromised sperm so that at
least a majority of dead sperm are quenched by the quenching
dye.
45. The method of claim 36 wherein the step of staining the
population of sperm further comprises the step of incubating the
population of sperm with a concentration of Hoechst 33342 less than
48 micromolar molar.
46. The method of claim 36 wherein the step of staining the sperm
with a DNA selective dye further comprises the step of diluting the
population of sperm with a first staining buffer including the DNA
selective fluorescent dye for an incubation period of between about
45 minutes and about an hour and a half.
47. The method of claim 46 wherein the step of staining said
portion of the population of sperm with a dead quenching dye
further comprises the step of diluting the sperm population with a
second staining buffer including the dead quenching dye after the
incubation period.
48. The method of claim 36 wherein the step of sorting further
comprises the steps of: a. establishing a fluid stream; b.
introducing the stained sperm into the fluid stream; c. exciting
DNA selective fluorescent dye associated with the DNA of the
stained sperm; d. detecting the fluorescence emission produced by
the stained sperm when excited; e. differentiating quenched and
unquenched sperm sub-populations within the stained sperm; f.
differentiating X-chromosome bearing sperm and Y-chromosome bearing
sperm in the unquenched sperm subpopulation based upon the detected
fluorescence of the unquenched sperm; and g. selecting sperm to
form at least one gender enriched sperm sample.
49. The method of claim 36 wherein the sorting steps are performed
with a flow cytometer.
50. The method of claim 47 wherein the flow cytometer is a
jet-in-air flow cytometer or a closed chamber flow cytometer.
51. The method of claim 36 wherein the sorting steps are performed
on a microfluidic chip.
52. The method of claim 48 wherein the step of exciting DNA
selective fluorescent dye associated with the DNA of the stained
sperm further comprising interrogating the stained sperm with a
laser operating at a UV wavelength.
53. A sex sorted sperm suspension comprising: a. viable, sex sorted
sperm associated with a DNA selective fluorescent dye; b. a medium
supporting sperm viability; c. a first dye; and d. a second
dye.
54. The method of claim 53 wherein the sex sorted sperm
subpopulation comprises an intermediate product collected from a
flow cytometer.
55. The method of claim 53 wherein the sex sorted sperm
subpopulation comprises an inseminate having trace amounts of the
first dye and the second dye.
56. The method of claim 53 wherein the sex sorted sperm
subpopulation is frozen.
57. The method of claim 53, wherein the first dye and the second
dye are different color dyes.
Description
[0001] This application is a National Stage of International
Application No. PCT/US2012/058008, filed Sep. 28, 2012, which
claims the benefit of, U.S. Provisional Application No. 61/541,438,
filed on Sep. 30, 2011, and U.S. Provisional Application No.
61/541,451, filed on Sep. 30, 2011, each are hereby incorporated
herein by reference.
TECHNICAL FIELD
[0002] Generally, this disclosure relates to staining and sorting
methods, such as Fluorescence Activated Cell Sorting (FACS), and
more particularly this disclosure relates to staining and sorting
methods which improve sort parameters in flow cytometry.
BACKGROUND
[0003] Effective pre-selection of sex has been accomplished in many
species following the development of reliable methods for
separating sperm into enriched X-chromosome and/or Y-chromosome
bearing subpopulations. Traditional sperm sorting methods often
rely on FACS for the detection of quantifiable differences in DNA
content of X-chromosome bearing sperm and Y-chromosome bearing
sperm, such as through flow cytometry. A typical step in these
methods includes staining a sperm population with a DNA selective
fluorescent dye that uniformly stains nuclear DNA. Hoechst 33342,
sometimes referred to as Hoechst bisbenzimide 33342, is the most
widely utilized stain for this purpose because it can be used in a
sufficient quantity to differentiate small variations in nuclear
DNA without exhibiting the toxicity of other fluorescent
stains.
[0004] Sorted sperm quality and purities improved with the
introduction of a dead quenching dye for differentiating membrane
compromised sperm from the population or populations of interest.
Membrane compromised sperm can include dead and dying sperm, which
may have fragmented and disintegrating nuclear DNA that obscures
the already narrow differences in X-chromosome bearing sperm and
Y-chromosome bearing sperm. Initially, propidium iodine was used
for this purpose, but has been shown to be toxic to sperm. Later,
FD&C red food dye No. 40,
6-hydroxy-5-[(2-methoxy-5-methyl-4-sulfophenyl)azo]-2-naphthalenesulfonic
acid (hereafter "red food dye No. 40" or "red 40"), was added to
the sperm staining process as the dead quenching dye for quenching
membrane compromised sperm and removing membrane compromised sperm
from the sort analysis.
[0005] When sex sorting sperm, ultimately a small variation in DNA
content is quantified differentiating X-chromosome bearing sperm
from Y-chromosome bearing sperm. In bovine, for example, Holsteins
have about a 3.8% difference in DNA content, while Jersey bulls
have about a 4.1% difference. Due to the inexact nature of
stoichiometric DNA staining, these small differences can be
difficult to differentiate. This difficulty may be exacerbated by
noise in the DNA staining complex, which can vary randomly in both
X-chromosome bearing sperm and Y-chromosome bearing sperm.
[0006] One previously unrealized problem that may exist in current
dead quenching staining regiments may be an over quenching of some
desired signal. This may occur with the presence of a dead
quenching dye in a sperm sample which does not associate with
membrane compromised sperm, but instead remains in the sample
quenching signals produced by membrane compromised sperm and
non-membrane compromised sperm alike. It may also be that some dead
quenching dye associates with healthy sperm cells. For these
reasons, quenching in the sample may slightly quench the overall
signal. While this may be happening to a far extent as compared to
the quenching of membrane compromised sperm, it can be relevant
when attempting to differentiate small differences in nuclear DNA
content.
[0007] The sperm sorting process is damaging to cells which are
non-regenerative time critical cells. The staining step can be the
especially harmful. While Hoechst 33342 can be used in non-toxic
concentrations, sperm must be incubated at elevated temperatures
and elevated pHs for sufficient Hoechst 33342 penetration with
sufficient uniformity for analysis or sorting. Each of elevating
sperm temperature and elevating sperm pH may contribute to sperm
damage. Therefore, a need exists for improvements to the staining
process which reduce stain times or reduce incubation temperatures
and/or pHs. Additionally, many chemicals added during sperm
processing negatively impact sperm viability. This can be
particularly true in sperm staining and sorting procedures.
Disclosure of Invention
[0008] Certain embodiments of the claimed invention are summarized
below. These embodiments are not intended to limit the scope of the
claimed invention, but rather serve as brief descriptions of
possible forms of the invention. The invention may encompass a
variety of forms which differ from these summaries.
[0009] One embodiment relates to a method of gender enriching one
or more sperm subpopulation utilizing a dead quenching dye and a
split enhancing dye. Such a method can begin by obtaining a
population of sperm which includes both X-chromosome bearing sperm
and Y-chromosome bearing sperm. At least a portion of that sperm
can be stained with a DNA selective fluorescent dye which
fluoresces when excited. The stained portion of sperm may then be
further stained with a dead quenching dye which selectively
quenches fluorescence emitted by the DNA selective fluorescent dye
within the membrane of compromised sperm. The stained portion of
sperm may additionally be stained with a split enhancing dye and
then sorted into one or more gender enriched subpopulations of
viable sperm.
[0010] Another embodiment relates to a method for gender enriching
one or more sperm subpopulations with a dead quenching dye having a
yellow or orangish color. Such a method can begin by obtaining a
population of sperm which includes both X-chromosome bearing sperm
and Y-chromosome bearing sperm. At least a portion of that sperm
can be stained with a DNA selective fluorescent dye which
fluoresces when excited. The stained portion of sperm may then be
further stained with a dead quenching dye which selectively
quenches fluorescence emitted by the DNA selective fluorescent dye
within the membrane of compromised sperm. The dead quenching dye
may be yellow, orange, or orangish red in appearance. Finally, the
stained sperm may be sorted into one or more gender enriched
subpopulations of viable sperm.
[0011] Still another embodiment relates to a sex sorted sperm
suspension in the form of either an intermediate product in the
sorting process, or as an artificial inseminate. The sex sorted
sperm suspension can include viable, sex sorted sperm including an
associated DNA selective fluorescent dye. The suspension may
additionally include a medium supporting sperm viability, as well
as, a first dye and a second dye.
BRIEF DESCRIPTION OF DRAWINGS
[0012] FIG. 1 illustrates a representation of a jet-in-air flow
cytometer used in certain embodiments described herein.
[0013] FIG. 2 illustrates an excitation curve for Hoechst 33342 as
compared to absorption curves for several dyes.
[0014] FIG. 3 illustrates bivariate histograms from a flow
cytometer sorting sperm with different dead quenching dyes.
[0015] FIG. 4 illustrates an example of parameters measured from a
univariate and bivariate plot in a flow cytometer.
[0016] FIG. 5 illustrates a graphical comparison of the quenching
capacity of various dyes as dead quenching dyes.
[0017] FIG. 6 illustrates a graphical comparison of the split
quality produced when sorting with various dyes.
[0018] FIG. 7A illustrates a graphical comparison of the quenching
capacity of various dyes as dead quenching dyes.
[0019] FIG. 7B illustrates a graphical comparison of the split
quality produced when sorting with various dyes.
[0020] FIG. 8 illustrates a graphical comparison of the quenching
capacity of various split enhancing dyes used in combination with a
dead quenching dye.
[0021] FIG. 9 illustrates a graphical representation of a split
enhancing capacity at various concentrations.
[0022] While the present invention may be embodied with various
modifications and alternative forms, specific embodiments are
illustrated in the figures and described herein by way of
illustrative examples. It should be understood the figures and
detailed descriptions are not intended to limit the scope of the
invention to the particular form disclosed, but that all
modifications, alternatives, and equivalents falling within the
spirit and scope of the claims are intended to be covered.
MODES FOR CARRYING OUT THE INVENTION
[0023] In certain aspects the present invention provides improved
staining procedures with particular benefits in the sex selection
or sex sorting of sperm. For example, certain aspects relate to
improvements in sorting sperm by quenching undesirable noise
arising from random signal variations produced by undesired dead
cells and reducing undesirable non-specific noise arising from
viable cells. Another aspect relates to an improved dead quenching
dye which with an improved capacity to quench signals from dead
sperm. These aspects may provide independent benefits in sort
speeds or improved sort purities, or may be combined to
synergistically further improve sorting. Alternatively, stain
concentrations or stain times and other harmful aspects of staining
may be reduced with the described improvements while maintaining
acceptable sorting parameters, such as speed and purity, perhaps
resulting in improved motility and viability in the sorted sperm
sample.
[0024] Existing staining protocols for sex sorting, or even bulk
sorting, sperm rely up the inclusion of F&DC red food dye No.
40 ("red food dye No. 40" or "red 40") as a dead quenching dye. The
maximal absorbance wavelengths of red food dye No. 40 overlaps the
maximal emissions wavelengths of fluorescent dyes, including
Hoechst 33342 when bound to nuclear or chromosomal DNA. Because red
food dye No. 40 differentially permeates membrane compromised sperm
cells and overlaps the emission spectra of the DNA selective
fluorescent dye, FRET (florescence resonance energy transfer)
between the light leaving the DNA-stain complex and the dead
quenching dye reduces the overall detected intensity of the light
emitted from membrane compromised sperm. The quenched, or dampened,
fluorescence from these cells provide fewer photons to the
detectors resulting in a distinctly lower signal. This distinctly
lower signal results in a noticeable separated subpopulation which
allows the exclusion ("gating out") of the membrane compromised
sperm during the sorting procedure. Since membrane compromised
sperm comprises largely non-viable sperm, excluding these cells
from the analysis results in an enriched sperm subpopulation with
respect to viability in the sex sorted subpopulation.
[0025] In addition to the desired signal produced by chromosomal or
nuclear DNA during sorting, non-specific florescence can be
produced from viable sperm during the sorting process. Non-specific
florescence may include florescence emissions not coming from the
DNA-stain complex, such as auto-florescence from NADH and NADPH,
stain that may have associated with mitochondrial DNA, stain that
may have associated with RNA, and/or stain that may have associated
with cellular lipophilic components. While the exact source of
non-specific noise from viable sperm is not known with certainty,
it was appreciated by applicants for the first time that this noise
may be, at least partially, at a different wavelength that the
signal of interest. Namely, non-specific noise may, at least
partially, occur in the 520 nm to 600 nm wavelength range, or
perhaps at about 520 nm. Certain embodiments of the present
invention provide split enhancing dyes which are impedance matched
to this non-specific noise. Such split enhancing dyes may help
improve sorting signals and sort purities by enhancing the
distinction between two sperm subpopulations.
[0026] In this way, staining procedures may be improved to enhance
splits by reducing the non-specific fluorescence of live sperm with
the addition of split enhancing dyes impedance matched to that
non-specific fluorescence. Since non-specific florescence is not
correlated with the sex chromosome of sperm cells, if non-specific
florescence has a high CV (coefficient of variation), then it may
contribute a "noise signal" to the CV of the populations of live
X-chromosome bearing and Y-chromosome bearing sperm. Even if the
non-specific florescence is very low (such as 0.05%-0.25% of total
florescence) if variation is high, it may contribute significant
variation, causing a reduction in the resolution between the two
closely related sex populations, resulting in what is generally
called a "poor split". The result of a poor split is a slower
sorting process, or conversely a good split is deemed essential to
a fast sorting process.
[0027] In one aspect the invention provides a method of selecting
gender enriched populations of sperm including the steps of: (1)
obtaining a population of sperm; (2) staining the population of
sperm with a DNA selective dye, a dead quenching dye, and, in some
cases, a split enhancing dye; and (3) sorting the stained
population of sperm. Certain embodiments described herein relate to
mixed dyes with enhance sorting properties, while other embodiments
relate to improved dead quenching dyes that improve sort
parameters, such as, sort speed and sort purity.
[0028] In the first step (1), a population of sperm is obtained.
The population of sperm can be obtained in the form of neat semen,
extended sperm, frozen thawed sperm or in combinations thereof. The
population of sperm can be obtained at the same location as the
remaining steps, or can be extended in an appropriate sperm buffer
for transport to a sorting facility. The sperm can be maintained at
room temperature, chilled, or even frozen in an appropriate buffer
for later use. The step of obtaining sperm can include obtaining a
frozen or chilled straw from storage, or even pooling frozen or
extended sperm.
[0029] The population of sperm can originate from mammals, such as
a non-human mammals listed by Wilson, D. E. AND Reeder, D. M.,
Mammal Species of the World, Smithsonian Institution Press, (1993),
the entire contents of which are incorporated herein by
reference.
[0030] In the second step (2), the population of sperm is stained
in a process which includes a DNA selective fluorescent dye, a dead
quenching dye and in some cases a split enhancing dye. The
population of sperm can include X-chromosome bearing sperm and
Y-chromosome bearing sperm. Additionally, each of the X-chromosome
bearing sperm and the Y-chromosome bearing sperm can include viable
sperm and nonviable sperm. Viable sperm can be considered sperm
with intact membranes while nonviable sperm can be considered sperm
with compromised membranes. Viable sperm, in the appropriate
dosage, will generally be capable of achieving fertilization in an
artificial insemination, while nonviable sperm, or membrane
compromised sperm, will be incapable of achieving fertilization in
an artificial insemination or will have a greatly reduced ability
to do so. However, some sperm capable of fertilization may have
compromised membranes, and some sperm with intact membranes may be
incapable of fertilization. The staining can take place in two
distinct steps. In the first step, at least a portion of the
population of sperm is incubated with a first staining buffer and a
DNA selective fluorescent dye. The purpose of the first step is to
stoichiometrically stain the DNA content of each cell in the sperm
population. Hoechest 33342 is described in U.S. Pat. No. 5,135,759,
for this purpose. However, other UV excitable dyes, as well as
visible light excitable dyes, fluorescent polyamides, fluorescent
nucleotide sequences, and sex specific antibodies could also be
used for this purpose.
[0031] Sperm in its natural state is often not readily permeable to
such dyes. In order to produce a uniform staining, the first step
of staining can include incubating at least a portion of the sperm
population at an elevated temperature in a first staining buffer at
an elevated pH in addition to the dye. Examples of appropriate
first staining buffers can be a TALP, TES-TRIS, TRIS citrate,
sodium citrate, or a HEPES based medium, each described in
WO2005/095960, incorporated herein by reference. An exemplary
modified TALP described in WO2001/37655, incorporated herein by
reference, is illustrated in Table 1.
TABLE-US-00001 TABLE 1 Modified TALP buffer Ingredient
Concentration NaCl 95.0 mM KCl 3.0 mM NaHPO.sub.4 0.3 mM
NaHCO.sub.3 10.0 mM MgCL.sub.2 6H.sub.2O 0.4 mM Na Pyruvate 2.0 mM
Glucose 5.0 mM Na Lactate 25.0 mM HEPES 40.0 mM bovine serum
albumin 3.0 mg/ml
[0032] As one example, the population of sperm, or a portion of the
population of sperm, could be diluted with the first buffer to
between 640.times.10.sup.6 and 40.times.10.sup.6 sperm/ml, to
between about 320.times.10.sup.6 and 80.times.10.sup.6 sperm/ml, or
to about 160.times.10.sup.6 sperm/ml in the first buffer. The DNA
selective florescent dye can be added to the sperm suspended in the
first buffer in a concentration of between about 10 .mu.M and 200
.mu.M; between about 20 .mu.M and 100 .mu.M, or between about 30
.mu.M and 70 .mu.M. The pH of the first buffer can be between about
6.8 and 7.9; about 7.1 and 7.6; or at about 7.4 in order to help
ensure a uniform staining of nuclear DNA. Those of ordinary skill
in the art will appreciate the pH can be elevated with the addition
of NaOH and dropped with the addition of HCl.
[0033] The population of sperm can be incubated between
30-39.degree. C., between about 32-37.degree. C., or at about
34.degree. C. The period of incubation can range between about 20
minutes and about an hour and a half, between about 30 minutes and
about 75 minutes, or for about 45 minutes to about 60 minutes. As
one example, the population of sperm can be incubated for about 45
minutes at 34.degree. C. Even within a single species, sperm
concentration and pH and other factors affecting stainability can
vary from animal to animal. Those of ordinary skill in the art can
appreciate minor variations for incubating sperm between species
and even between breeds or animals of the same breed to achieve
uniform staining without over staining a population of sperm.
[0034] At the end of the incubation period, when the DNA selective
fluorescent dye has sufficiently saturated the population of sperm
to differentiate X-chromosome bearing sperm from Y chromosome
bearing sperm, a second step of staining can include a further
dilution in a second staining buffer that contains one or more
additional dyes. The one or more additional dyes can include a
single dye for the purpose of permeating and quenching signals from
membrane compromised sperm cells, as well as, for reducing signal
noise. The one or more additional dyes can also include the
combination of a dead quenching dye and a split enhancing dye. The
term "dead quenching dye" can be understood to include dyes which
differentially associate with membrane compromised sperm. It may be
that these dyes enter membrane compromised sperm cells more easily
because the membranes are breaking down or otherwise increasingly
porous, but it may also be that dead quenching dyes readily enter
all sperm cells and that healthy sperm cells act to pump dead
quenching dyes out faster than membrane compromised sperm. In
either case, the sperm cells with which the dead quenching dyes
associate includes a large portion of dead and dying sperm cells,
although not necessarily all dead and dying sperm cells.
[0035] In an alternative embodiment, the dead quenching dye and/or
the split enhancing dye may be introduced with the first staining
buffer having the DNA selective dye, or in both the first staining
buffer and the second staining buffer.
[0036] The second buffer can be applied in an equal volume to half
the current sperm concentration. Similarly, the volume of the
second buffer can be selected to achieve a desired final
concentration of sperm for further processing, such as between
about 320.times.10.sup.6 and 20.times.10.sup.6 sperm/ml, between
about 160.times.10.sup.6 and 40.times.10.sup.6 sperm/ml, or about
80.times.10.sup.6 sperm/ml. The second buffer can have a pH
coordinated to bring the overall pH back to an ideal pH for sperm.
In the case of bovine, where the pH has been taken to 7.4 with the
first buffer, the second buffer can be applied at 5.5 in order to
bring the final pH back to 6.8. The specific pH can vary from
species to species, but that those of skill in the art can
determine appropriate sperm pH and coordinate the second buffer to
achieve a particular desired pH. In another embodiment, the second
buffer can have the same pH as the first buffer.
[0037] The second buffer can be selected as a buffer similar to the
first buffer. The pH of the second buffer can be reduced with the
addition of HCl. As one example, the modified TALP can be used with
the addition of a dead quenching dye, a split enhancing dye and
with the addition of egg yolk, for example 4% egg yolk.
[0038] The dead quenching dye can selectively quench the
fluorescence of unwanted cells. To achieve this, the dye must enter
unwanted cells and efficiently absorb the fluorescent emission of
the DNA selective dye. In the case of sperm sorting, membrane
compromised sperm are permeable to many dyes. Red food dye No. 40
was previously used for this purpose. However, improvements in
quenching efficiency are possible where the dead quenching dye is
impedance matched more closely to the excitation of the DNA
selective fluorescent dye. In the case of sperm, a common DNA
selective fluorescent dye is Hoechst 33342, described above, which
is expected to fluoresce at a maximum emission at about 483 nm in
the emission spectra. Improved quenching dyes may therefore be
impedance matched to this emission value when they have
corresponding absorption maximums at near the same value. Table 2
below illustrates several food dyes and their expected absorption
maxima in water. Additionally, FIG. 2 provides a visual
representation of the emission intensity of Hoechest 33342, when
excited by a UV laser in comparison to the absorption spectra of
yellow food dye No. 5 (Y5), yellow food dye No. 6 (Y6), red food
dye No. 40 (R40), red food dye No. 3 (R3), red food dye No. 4 (R4),
phenol red, and violet.
TABLE-US-00002 TABLE 2 Expected Absorption Maxima (nm) of FD&C
Dyes and Phenol Red Dye Maxima.sup.a(nm) Solvent Absorption Yellow
5 water 422 Phenol Red water 440 560 Yellow 6 water 480 Red 40
water 505 Red 2 water 520 Red 4 (natural) water 520 555 Red 3 water
530 Blue 2 water 610 Green 3 water 625 Blue 1 water 627 .sup.aThe
maxima will vary slightly due to variations in solvent.
[0039] Exemplary dead quenching dyes can be those having lower
absorption maxima than red food dye No. 40. Such dyes may be
visually characterized as yellow, orange, or orangish-red in color
and may have absorption maxima in the range of between about 420 nm
and about 500 nm. Exemplary dyes can include yellow dyes, such as
FD&C yellow food dye no. 6, Disodium
6-hydroxy-5-[(4-sulfophenyl)azo]-2-naphthalenesulfononate,
(hereafter "yellow food dye no. 6" or "yellow 6"); and FD&C
yellow food dye No. 5, Trisodium
(4E)-5-oxo-1-(4-sulfonatophenyl)-4-[(4-sulfonatophenyl)hydrazono]-3-pyraz-
olecarboxylate, (hereafter "yellow food dye no. 5" or "yellow 5").
Both food dyes demonstrate an ability to quench membrane
compromised sperm cells in the sex sorting process.
[0040] The dead quenching dye is selected for its ability to
permeate membrane compromised sperm cells and to dampen the
fluorescence produced by the DNA selective fluorescent dye in those
cells. Some orange and yellow food dyes demonstrate an improved
ability to differentiate membrane compromised sperm from healthier
sperm. For example, yellow food dye No. 6 tends to exhibit superior
quenching to previous dead quenching dyes. Yellow food dye No. 6
may permeate membrane compromised sperm more effectively, or may
possess a greater ability to absorb photons. At the same time some
yellow dyes demonstrate less dampening to the overall signal. These
benefits allow for less DNA selective fluorescent dye with the
first staining buffer and less yellow dye with the second staining
buffer, as compared the amount of red food dye No. 40 previously
used.
[0041] As dead quenching dyes, yellow food dye No. 6 can be used in
a concentration of greater than 12.5 .mu.M, between 12.5 .mu.M and
250 .mu.M, or between 20 .mu.M and 125 .mu.M. Yellow food dye No. 5
can be used in concentrations greater than 125 .mu.M, or between
about 125 .mu.M and 500 .mu.M.
[0042] Exemplary split enhancing dyes can be red dyes other than
red food dye no. 40, or perhaps even redish and violet dyes. The
local absorption maximum wavelength of split enhancing dyes may be
greater than that of red food dye No. 40, namely greater than 505
nm. The local absorption maximum wavelength may be greater than
about 520 nm. Alternatively, the split enhancing dye can have a
local absorption maximum wavelength between about 520 nm and about
600 nm. Exemplary dyes can include phenol red, sometimes referred
to as phenolsulfonphthalein or PSP; natural red food dye No. 4,
known as carmine or natural red 4 (hereafter "carmine" or "red food
dye No. 4"); and FD&C red food dye No. 3,
2-(6-Hydroxy-2,4,5,7-tetraiodo-3-oxo-xanthen-9-yl)benzoic acid,
(hereafter "red food dye No. 3" or "red 3"). The examples below
demonstrate phenol red and red food dye No. 4 as improving the
split quality at a number of concentrations. Red food dye No. 3
also improves sorting at some concentrations. With reference to
Table 2, Phenol red is believed to have a maximum absorption at
about 560 nm to 570 nm (in the red molecular form), red food dye
No. 4 is believed to have local maximum absorption wavelengths at
520 nm and 555 nm, while red food dye No. 3 has an absorption
maximum at about 530 nm. Dyes having similar molecular weights and
absorption maxima are expected also provide improvements in
sorting. For example, dyes having local absorption maxima in the
range of about 520 nm to about 600 nm, or about 530 nm to about 580
nm are expected to also provide improvements in the signal to noise
ratio. Possible autofluorescence and other unintended fluorescence,
such as possibly Hoechst 33342 bound to mitochondrial DNA may to
emit in the spectral range of about 520-600 nm. Therefore, by
impedance matching a split enhancing dye to have local absorption
maxima at those wavelengths, noise can be reduced in the overall
signal.
[0043] In some embodiments, the split enhancing dye can be used in
addition to a dead quenching dye, while in other embodiments the
split enhancing dye can double as a dead quenching dye. As one
example, phenol red, red food dye No. 4, or red food dye No. 3 can
be used as split enhancing dyes in combination with yellow food dye
No. 6 for quenching membrane compromised sperm. Each of phenol red,
red food dye No. 4, and red food dye No. 3 have surprisingly been
found to reduce noise and enhance splits independent of dead
quenching in sperm sorting.
[0044] Phenol red and red food dye No. 4 may be used as a split
enhancing dye at concentrations between 0.1 .mu.M, and 1200 .mu.M,
and between 5 .mu.M and 620 .mu.M, and between 15 .mu.M and 125
.mu.M. Red food dye No. 3 may be used as a split enhancing dye in
concentrations between about 25 .mu.M and 600 .mu.M, and 150 .mu.M
and 600 .mu.M.
[0045] In some embodiments split enhancing dyes may be used for
quenching membrane compromised sperm, although they tend to be less
efficient at doing so and require greater concentrations. For
example, phenol red can be used for quenching membrane compromised
sperm in concentrations between about 250 .mu.M, and about 1250
.mu.M.
[0046] In step (3) the stained population of sperm can be sorted,
such as by flow cytometry. With reference to FIG. 1, a flow
cytometer (10) is shown for sorting stained sperm. The flow
cytometer (10) includes a cell source (12) supplying a sample for
sorting. The sample includes the stained sperm, such as sperm
stained with a DNA selective fluorescent dye and one or more other
dyes. The stained sperm are deposited within a nozzle (14) and
introduced into a fluid stream (16) of sheath fluid (18). The
sheath fluid (18) can be supplied by a sheath fluid source (20) so
that as the cell source (12) supplies the sperm into the sheath
fluid (18) they are concurrently fed through the nozzle (14). In
this manner the sheath fluid (18) forms a fluid stream coaxial to
the sample having stained sperm. Since the various fluids are
provided to the flow cytometer (10) at some pressure, they flow out
of nozzle (14) and exit at the nozzle orifice (22). By providing an
oscillator (24) which may be very precisely controlled through an
oscillator control (26), pressure waves may be established within
the nozzle (14) and transmitted to the fluids exiting the nozzle
(14) at nozzle orifice (22). Since the oscillator (24) acts upon
the sheath fluid (18), the fluid stream (16) exiting the nozzle
orifice (22) eventually and regularly forms drops (28) at precise
frequencies and velocities. Because the stained sperm are
surrounded by the fluid stream (16) or sheath fluid environment,
the drops (28) may contain within them individually isolated
spermatozoa.
[0047] Since the drops (28) can contain individual spermatozoa, the
flow cytometer can be used to sort sperm based upon individual cell
characteristics. This is accomplished through a cell sensing system
(30). The cell sensing system (30) includes at least a sensor (32)
responsive to the cells contained within fluid stream (16). The
cell sensing system (30) may cause an action depending upon the
relative presence or relative absence of a characteristic. Certain
characteristics, such as the relative DNA content of sperm cells,
can be detected through excitation with an electromagnetic
radiation source (34), such as a laser generating an irradiation
beam to which the stained sperm are responsive. The electromagnetic
radiation source (34) can be a laser operated at UV wavelength,
such as at about 355 nm laser operated at 175 mW. Alternatively, a
laser can be run at a higher power and split between several fluid
streams.
[0048] The characteristics of individual sperm, particularly the
presence of an X-chromosome or a Y-chromosome can be determined
from the detected fluorescence produced in response to the
electromagnetic radiation source (34). The DNA selective
fluorescent dye binds stoichiometrically to sperm DNA. Because
X-chromosome bearing sperm contain more DNA than Y-chromosome
bearing sperm, the X-chromosome bearing sperm can bind a greater
amount of DNA selective fluorescent dye than Y-chromosome bearing
sperm. Thus, by measuring the fluorescence emitted by the bound dye
upon excitation, it is possible to differentiate between X-bearing
spermatozoa and Y-bearing spermatozoa.
[0049] In order to achieve separation and isolation based upon
stained sperm characteristics, emitted light can be detected by the
sensor (32) and the information fed to an analyzer (36) coupled to
a droplet charger which differentially charges each drop (28) based
upon the characteristics of the stained sperm contained within that
drop (28). In this manner the analyzer (36) acts to permit the
electrostatic deflection plates (38) to deflect drops (28) based on
whether or not they contain the appropriate particle or cell.
[0050] As a result, the flow cytometer (10) acts to separate
stained sperm by causing the drops (28) containing sperm to be
directed to one or more collection containers (40). For example,
when the analyzer differentiates sperm cells based upon a sperm
cell characteristic, the droplets entraining X-chromosome bearing
spermatozoa can be charged positively and thus deflect in one
direction, while the droplets entraining Y-chromosome bearing
spermatozoa can be charged negatively and thus deflect the other
way, and the wasted stream (that is droplets that do not entrain a
particle or cell or entrain undesired or unsortable cells) can be
left uncharged and thus is collected in an undeflected stream into
a suction tube or the like as discussed in U.S. patent application
Ser. No. 09/001,394, hereby incorporated by reference herein.
Naturally, numerous deflection trajectories can be established and
collected simultaneously.
[0051] FIG. 3 illustrates comparisons of bivariate plots generated
in sex sorting sperm which reflect the intensity of the excited DNA
selective fluorescent dye during sorting. Three bulls were stained
with equal amounts of Hoechst 33342 and with an equal amount of
yellow food dye No. 6 and red food dye No. 40. The region labeled
as R4 surrounds what is considered the "dead" sperm population,
while the region R1 is centered on viable, oriented sperm. It can
be seen that for each bull yellow food dye no. 6 provided superior
quenching as for each bull the "dead" population, having the
majority of the membrane comprised sperm, was pulled further away
from the "live" population as compared to red food dye No. 40.
[0052] FIG. 4 illustrates an example bivariate plot and univariate
histogram of the parameters measured during sex selection by a FACS
on a flow cytometer. The relative intensity of the live, or
non-membrane compromised sperm can be seen on the bivatiate plot
having a height labeled "B," while the relative intensity of the
quenched dead, or quenched membrane compromised sperm is labeled
"A." The differences in magnitude of lines "A" and "B" demonstrate
the degree to which a membrane compromised subpopulation of sperm
is quenched and may be represented as a fraction or a percentage.
Without a dead quenching dye, both populations of sperm would
overlap to a large extent, with unpredictable variations in the
dead sperm.
[0053] The univarite histogram demonstrates the number of counts at
particular values in the flow cytometer. Each peak represents one
of either X-chromosome bearing sperm, or Y-chromosome bearing
sperm, with some overlap seen at the base. The amount of separation
between the peaks can be characterized in a number of ways. Here
the line is indicated at "C" provides an indication of the peak
height, whereas "D" provides an indication of the magnitude for the
valley separating the peaks. High "D" values and low "C" values
would indicate minimal overlap in the subpopulations and excellent
splits, whereas when the length of C and D are equal, there is
effectively no split. Split quality may be characterized as a ratio
of the distances indicated by C and D.
Example 1
Comparison of Dead Quenching Dyes for Post Thaw Motility Sperm
Motility in Bovine
Collection--
[0054] Sperm was collected from 10 different bulls on a routine
collection schedule using an artificial vagina over the course of 4
days. The 10 bulls included both Jersey bulls and Holstein bulls.
All ejaculates contained greater than 60% progressive motility and
greater than 70% morphological normal sperm. Antibiotics were added
within 15 minutes of collection.
Staining--
[0055] Red food dye treatment 40%--A reduced volume of red food dye
No. 40 control was established. Sperm was diluted to
160.times.10.sup.6 sperm per ml in a modified TALP buffer, as
described in Table 1, at a pH of 7.4. Samples collected from Jersey
bulls were incubated with 16 .mu.l of Hoechst 33342 per 2 ml of
sample for between 45 and 60 minutes at 34.degree. C., while
samples collected from Holstein bulls were incubated 17 .mu.l of
Hoechst 33342 per 2 ml of sample for between 45 and 60 minutes at
34.degree. C. After incubation an equal volume of a second modified
TALP was added reducing the concentration to 80.times.10.sup.6. The
second modified TALP includes the components described in Table 1
with the addition of 4% egg yolk, 40 .mu.M red food dye No. 40 (20
g/L) and the pH dropped to 5.5 with HCl.
[0056] Yellow Food dye treatment--Yellow food dye was included in a
second group at an equal concentration. Sperm was diluted to
160.times.10.sup.6 sperm per ml in a modified TALP buffer, as
described in Table 1, at a pH of 7.4. Samples collected from Jersey
bulls were incubated with 14 .mu.l of Hoechst 33342 per 2 ml of
sample for between 45 and 60 minutes at 34.degree. C., while sample
collected from Holstein bulls were incubated 15 .mu.l of Hoechst
33342 per 2 ml of sample for between 45 and 60 minutes at
34.degree. C. After incubation an equal volume of a second modified
TALP was added reducing the concentration to 80.times.10.sup.6. The
second modified TALP includes the components described in Table 1
with the addition 4% egg yolk, 20 g/L yellow food dye No. 6 and a
pH dropped to 5.5 with HCl.
Sorting--
[0057] Just prior to sorting, each sample was filtered though a 40
.mu.m nylon mesh. Each sample was sorted with an MoFlo SX XDP
(Beckman Coulter, Inc., CA USA) operating at 40 psi. A
tris-citrate-fructose sheath fluid was used comprising
Tris(hydroxymethyl)aminomethane (Sigma Chemical Co, St. Louis, Mo.,
USA) citric acid monohydrate (Sigma Chemical Co, St. Louis, Mo.,
USA) and fructose (Sigma Chemical Co, St. Louis, Mo., USA).
Antibiotics were additionally added to the sheath fluid.
[0058] Unquenched sperm having the desired sex characteristics were
collected into a single tube with a tris-egg yolk catch fluid and
the remaining sperm was removed with waste. The tris-egg yolk catch
fluid comprised 20% egg yolk, Tris(hydroxymethyl)aminomethane (Tris
200 mM; Sigma Chemical Co, St. Louis, Mo., USA), citric acid
monohydrate (65 mM; Sigma Chemical Co, St. Louis, Mo., USA),
fructose (56 mM; Sigma Chemical Co, St. Louis, Mo., USA) and
antibiotics, where the sample remained for a maximum of
approximately three hours.
Freezing--
[0059] Prior to freezing, the sorted sperm sample was cooled to
about 5.degree. C. and extended with a Tris-citrate-fructose
solution similar to the catch fluid but additionally containing 12%
glycerol. The cooled sorted sample was centrifuged and resuspended
in a Tris-citrate-fructose solution with 20% egg yolk solution and
6% glycerol to arrive at a final concentration of 10.times.10.sup.6
sperm/ml. Sperm was stored in divided into 2.1.times.10.sup.6 doses
and stored in 0.25 ml straws which were then cryopreserved with
liquid nitrogen vapor.
Results--
[0060] Straws were thawed the following day for motility
measurements at 0 hour and 3 hours. Percent intact acrosomes were
measured as well, and the overall averages over all bulls on each
day are illustrated in Table 3. Each bull tended to average higher
post thaw motilies at 0 hour and at 3 hours as well as improved
acrosomal integrity.
TABLE-US-00003 TABLE 3 Post thaw Motility Bovine Motility % Average
0 Hour Red 56.6% Average 0 Hour Yellow 57.7% Average 3 Hour Red
47.0% Average 3 Hour Yellow 49.0% Average PIA Red 70.8% Average PIA
Yellow 71.3%
Example 2
Comparison for Dead Quenching Dyes for Sorting Parameters in
Bovine
Collection--
[0061] 8 Sperm collections were taken from 7 different bulls on a
routine collection schedule using an artificial vagina. The 7 bulls
included both Jersey bulls and Holstein bulls. All ejaculates
contained greater than 60% progressive motility and greater than
70% morphological normal sperm. Antibiotics were added within 15
minutes of collection. Portions of each collected sample received
three different dead quenching dye treatments.
Staining--
[0062] Red food dye No. 40 treatment 100% (control)--A control was
established with a conventional volume of red food dye No. 40.
Sperm was diluted to 160.times.10.sup.6 sperm per ml in a modified
TALP buffer, as described in Table 1, at a pH of 7.4. Samples
collected from Jersey bulls were incubated with 16 .mu.l of Hoechst
33342 per 2 ml of sample for 60 minutes at 34.degree. C., while
sample collected from Holstein bulls were incubated 17 .mu.l of
Hoechst 33342 per 2 ml of sample for between 45 and 60 minutes at
34.degree. C. After incubation, an equal volume of a second
modified TALP was added reducing the concentration to
80.times.10.sup.6. The second modified TALP includes the components
described in Table 1 with the addition 4% egg yolk, 125 .mu.M red
food dye No. 40 and a pH dropped to 5.5 with HCl.
[0063] Red food dye No. 40 treatment 40%--A second group was
prepared in the same way as the first, but with a 40% concentration
of the red food dye No. 40, 50 .mu.M red food dye No. 40.
[0064] Yellow food dye No. 6 treatment--Yellow food dye was
included in the final group and was prepared in the same manner as
Example 1. The concentration of yellow food dye No. 6 corresponds
to the 40% red food dye No. 40 treatment at a concentration of 50
.mu.M.
Sorting--
[0065] Just prior to sorting, each sample was filtered though a 40
.mu.m nylon mesh. Each sample was sorted with a MoFlo SX XDP
(Beckman Coulter, Inc., CA USA) operating at 40 psi. The sheath
fluid described in Example 1 was used for sorting.
[0066] The event rate was held as close to 40,000 per second as
possible for each sort and each sample was sorted for X-chromosome
bearing sperm. The eight sorts were carried out on 6 different
machines in order to minimize instrumentation effects and to
average out differences in each instruments performance due to
nozzle, beam shaping, and drop drive frequency.
Results--
[0067] In Tables 3-6 benefits to the sorting speed and sorting
resolution are demonstrated with a reduced concentration of yellow
food dye No. 6. Sperm samples quenched with yellow food dye No. 6
are denoted Y6. The control amount of red food dye No. 40 is
identified as R40-100%, and R40-40% represents a red food dye No.
40 at a 40% concentration as compared to the control (125 .mu.M vs.
50 .mu.M).
[0068] Table 4 illustrates the average event rates across each
sample and demonstrates they were maintained within just over 1%.
Table 5 demonstrates a minor improvement in sort purity using a
smaller amount of red food dye No. 40, and a further improvement in
purity using yellow food dye No. 6, with a corresponding reduction
in DNA selective fluorescent dye. Table 6 demonstrates a 14%
increase in sort speed with the yellow food dye No. 6 is used as a
dead quenching dye. This is a significant improvement given that
the event rates were separated by only about 1% and that the sort
purities were also very similar. Table 7 demonstrates that the X
region contains 42.7% of the sperm population in the samples
quenched with yellow food dye No. 6, as opposed to 39.1% and 38.4%
for each of the red food dye quenchers. And this appears where
yellow food dye No. 6 out performs the red food dyes. The improved
resolution allows for excluding fewer cells which were not intended
to be excluded resulting in a larger percentage of cells in sort
region, and faster sort times at similar event rates.
[0069] As the sorting region and sorting speeds improve, Table 8
illustrates the number of coincident aborts also increase.
TABLE-US-00004 TABLE 4 AVERAGE EVENT RATE (events per second) R40-
100% 40412 R40- 100% 40255 Y6 40675
TABLE-US-00005 TABLE 5 AVERAGE PURITY (percent) R40- 100% 89.5 R40-
100% 89.2 Y6 90.5
TABLE-US-00006 TABLE 6 AVERAGE SORT SPEED (sorts per second) R40-
100% 5406 R40- 100% 5522 Y6 6194
TABLE-US-00007 TABLE 7 AVERAGE X REGION (percent) R40- 100% 38.4
R40- 100% 39.1 Y6 42.7
TABLE-US-00008 TABLE 8 AVERAGE ABORT RATE (aborts per second) R40-
100% 3310 R40- 100% 3292 Y6 3540
Example 3
Comparison of Dead Quenching Dyes for Sperm Motility in Deer and
Elk
Collection--
[0070] Each of deer and elk were collected in the Tris-egg yolk
catch fluid described as a catch media in Example 1, and shipped
for sorting.
Staining--
[0071] A portion of each of the deer and the elk were stained by
the red food dye No. 40 treatment 40% with 16 .mu.L Hoechst 33342
and the yellow food dye No. 6 treatment with 14 .mu.L Hoechst 33342
as described in Example 1.
Sorting and Freezing--
[0072] Samples were each bulk sorted with the same machine and
parameters described in Example 1. Both sorted X and sorted Y sperm
were collected into a single catch. The sorted samples were then
frozen like those described in Example 1.
Results--
[0073] Frozen thawed samples were then tested for post thaw
motilities and post thaw DNA fragmentation. Post thaw motilities
were slightly higher in Elk sorted with a yellow quencher, while a
more significant difference existed in progressive motility. In
Table 10, post thaw DNA fragmentation in Elk can be seen at about
double after 48 hours when red food dye No. 40 is compared to
yellow food dye No. 6 as a dead quencher. In Tables 9 and 11, Deer
and Elk each demonstrated improved motility and progressive
motility in the samples quenched with yellow food dye No. 6 and
stained with 14 .mu.L of Hoechst 33342 as compared to the red food
dye No. 40 with 16 .mu.L of Hoechst 33342.
TABLE-US-00009 TABLE 9 Post Thaw Motility Elk Motile Progressive
RED TALP, 16st 0 HR 51.0 29.0 Y6, 14st 55.5 38.0
TABLE-US-00010 TABLE 10 Post Thaw DNA fragmentation Elk Pre-sort
Post Sort RED TALP, 16st 0 HR 2.3 0.0 24 HR 5.6 0.3 48 HR 6 0.7 Y6,
14st 0 HR 2.3 0.0 24 HR 3.3 0 48 HR 3.7 0.3
TABLE-US-00011 TABLE 11 Post Thaw Motility Deer Motile Progressive
RED TALP, 16st 0 HR 59.8 43.0 Y6, 14st 67.5 53.2
Example 4
Comparison of Dead Quenching Dyes for Sperm Motility in Dog
Collection--
[0074] Sperm was collected from a single canine at room temperature
into CaniPro Chill 5, available from Minitube, WI, USA, then
centrifuged into a pellet and resuspended in a Tris buffer at a pH
of 6.8.
Staining--
[0075] Samples were extended to 40.times.10.sup.6 sperm/ml in 1 ml
volumes with the Tris buffer described in Example 1 but set to a pH
of 7.2. Ten samples were then stained 4, 4, 5, 5, 7, 8, 8, 9, 9,
and 10 .mu.L of Hoechst 33342 and quenched with one of two
quenching dyes at a concentration of 50 .mu.M in a second buffer
Tris buffer.
[0076] Red food dye No. 40 quencher--1 ml Tris at a pH 6.3 was
added with red food dye No. 40 into samples stained with 4, 5, 8,
9, 10 .mu.L Hoechst 33342. The red food dye No. 40 was added at a
concentration of about 50 .mu.M.
[0077] Yellow food dye No. 6 quencher--1 ml Tris at a pH 6.3 was
added with yellow food dye No. 6 into samples stained with 4, 5, 7,
8, 9 .mu.L Hoechst 33342. The yellow food dye No. 6 was added at
the same concentration as the red food dye No. 40 quencher, at
about 50 .mu.M.
[0078] After quenching, each sample had a total volume of 2 mL
Sorting--
[0079] 5 million cells were sex sorted with a MoFlo SX XPD into 50
mL Falcon tubes having 3.5 mL of a Tris-egg yolk catch fluid,
described in Example 1 for both X and Y populations. Two samples
were sorted, the red food dye No. 40 quenched treatment with 9
.mu.L Hoechst 33342 and the yellow food dye No. 40 quenched
treatment with 7 .mu.L Hoechst 33342.
[0080] On the sorter, the samples sorted with red quenched
treatment with 9 .mu.L Hoechst 33342 demonstrated 50.73 percent of
sperm in the X region and 8.92 percent were gated as dead. Samples
sorted with the yellow quencher had 48.7 percent of sperm in the X
region and only 4.42 percent of the sperm gated as dead.
Freezing--
[0081] Straws were then frozen and stored in liquid nitrogen.
Thawing--
[0082] Straws were thawed for 30 sec in a 38.degree. C. water bath
and their motilities were examined on CASA.
Results--
[0083] Table 12 illustrates the average motilities and progressive
motilities for the sorted treatments. Canine sperm quenched with
yellow food dye No. 6 provided about 4.5% more motile sperm in the
X population and 6.5% more motile sperm in the Y population.
Similarly, the yellow quenched dye provided 7% better progressive
motility in the X population and 8% better progressive motility in
the Y population.
TABLE-US-00012 TABLE 12 Dead quenching dye motilities TIME Total
cells Motile Progressive X YELLOW 6 AVERAGE 0 HR 192 24 18.5 Y
YELLOW 6 AVERAGE 0 HR 322 25 21 X RED TALP AVERAGE 0 HR 312 19.5
11.5 Y RED TALP AVERAGE 0 HR 328 18.5 13
Example 5
Comparison of Dead Quenching Dye Amounts Vs Hoechst 33342 Stain
Amounts
Collection--
[0084] A single Jersey bull was collected at an initial sperm
concentration 1900.times.10.sup.6 sperm/ml in a volume of 5 ml. The
progressive motility of the sperm was 65% with normal morphologies
greater than 65%.
Staining--
[0085] The entire ejaculate of sperm was suspended in first
staining buffer, specifically a 7.4 pH TALP described in TABLE 1,
to a concentration of 160.times.10.sup.6 sperm per mL (determined
on nucleocounter) and divided into three aliquots of about 20 mL
into 50 mL Falcon tubes and pre-warmed for 10 minutes at 34.degree.
C. The DNA selective fluorescent dye, Hoechst 33342, was added and
samples were held at 34.degree. C. for 60 minutes. 3 different
Hoechst 33342 Stain Levels were used=12 .mu.L, 14 .mu.L and 16
.mu.L per 2 mL (effective concentrations of 48 .mu.M, 56 .mu.M, 64
.mu.M).
[0086] Preparation of the second buffer including the dead
quenching dye--A 2 L bag of TALP, described in TABLE 1, was
adjusted to pH 5.60 using HCl and then sterile filtered. (Note:
This test did not use 0.3% v/v BSA or 4% v/v Egg Yolk in the second
buffer). For each of the four dyes tested (R40--red food dye No.
40, Y5--yellow food dye No. 5, Y6--yellow food dye No. 6 and
PR--phenol red), an appropriate number of milligrams of each powder
was placed in a Erlenmeyer Flask and then an exact amount of TALP
pH 5.60 was added to create a 250 .mu.M concentration of the dye.
The result was a working TALP stock for each dye with a 100% (125
.mu.M) relative amount of dye 50% relative (62.5 .mu.M) and 20%
relative (25 .mu.M) solutions were made by dilution of 100% by TALP
pH 5.60.
[0087] Controls--Single tubes of stained sperm at each of the three
Hoechst 33342 concentrations were treated with TALP pH 5.60 which
had no dead quenching dye present. Single tubes using Vitamin B12
(red colored chemical) with stock concentration of 15 .mu.M (12%
relative) were tested.
Sorting and Data Acquisition--
[0088] After this "bulk" staining for 60 minutes, 1 mL aliquots of
stained sperm were combined with 1 mL aliquots of the second buffer
including the dead quenching dyes. Samples sat for approximately 30
minutes at room temperature before being analyzed on a MoFlo SX
(Beckman Coulter, USA) sperm sorting flow cytometer. Event rates
were held as close to 13,000 as possible at the point of data
acquisition.
[0089] The total number of individual treatments was 42 tubes, each
containing 2 mL of stained sample. The alignment of the sorter was
established using nuclei and confirmed with live sample from the
50% Red 40 series. Once good alignment was established, each tube
was placed on the sorter long enough to establish a stabile dead
gate population (about 30 seconds) and then a screenshot was taken
and saved as a .jpeg image. This approach of rapidly documenting
each sample is used to assure the most consistent alignment between
all samples. Realignment of sorter will not cause differences in
the intensities of live and dead gate populations but will cause
differences in split quality.
Results--
[0090] FIG. 4 illustrates an example histogram. The ratio of dead
gate intensity divided by live gate intensity is created by
dividing the distance "A" by the distance "B" shown as a
percentage. Lower values mean higher levels of quenching. The ratio
of peak height divided by valley height is created by dividing the
distance "C" by the distance "D". A value of 1.00 means "no split"
while higher values mean "better splits".
[0091] TABLE 13 shows the ratios created by making this measurement
on each of 42 histograms generated in the data acquisition
described above. 16 .mu.L data was omitted in the split data of
TABLE 13 because there was mostly no split in nearly all samples
(due to "overstained condition"). FIG. 5 shows the average data for
dead gate intensity divided by live oriented gate intensity. FIG. 6
illustrates the average data for 12 .mu.L and 14 .mu.L stain series
for the height of peak divided by height of valley.
[0092] From the dead and live intensity data, the absorption of the
four dyes (ability to create a dead gate population) is ordered as
red food dye No. 40 and yellow food dye No. 6 being about equal and
better than the remaining dyes. Of the remaining dyes yellow food
dye No. 5 had better quenching properties than phenol red. From the
split quality data, food dye improves the quality of split compared
to no food dye control. Relative level of 20% food dye might be
better than 40%.
TABLE-US-00013 TABLE 13A dead quenching and split enhancing
capacities Hoechst No stain Red 40 Yellow 6 .mu.L/2 mL 0 125 .mu.M
62.5 .mu.M 25 .mu.M 125 .mu.M 62.5 .mu.M 25 .mu.M Dead Intensity 16
100% 35% 50% 65% 40% 52% 70% 14 100% 41% 53% 72% 40% 52% 74% 12
100% 37% 53% 68% 37% 50% 68% Average 100% 38% 52% 68% 39% 51% 71%
Height of Peak/Height of Valley 16 1.00 1.21 1.00 1.00 1.26 1.00
1.13 14 1.44 2.00 1.62 1.94 1.80 1.62 2.07 12 1.50 1.75 1.65 2.05
1.73 1.70 2.05 Average 1.47 1.88 1.64 2.00 1.77 1.66 2.06
TABLE-US-00014 TABLE 13B dead quenching and split enhancing
capacities Hoechst Yellow 5 Phenol Red B12 .mu.L/2 mL 125 .mu.M
62.5 .mu.M 25 .mu.M 125 .mu.M 62.5 .mu.M 25 .mu.M 0.25 Dead
Intensity 16 55% 70% 90% 78% 80% 90% 100% 14 63% 77% 90% 80% 90%
97% 100% 12 54% 74% 90% 80% 90% 94% 100% Average 57% 74% 90% 79%
87% 94% 100% Height of Peak/Height of Valley 16 1.03 1.00 1.00 1.00
1.00 1.00 1.00 14 1.92 1.70 1.54 1.75 1.87 1.65 1.62 12 1.72 1.60
1.90 1.49 1.62 1.82 1.61 Average 1.82 1.65 1.72 1.62 1.75 1.74
1.62
Example 6
Comparison of Dead Quenching Dye for Yellow Food Dye No. 6 and
Phenol Red
Collection--
[0093] A single Jersey bull was collected at an initial sperm
concentration 1810.times.10.sup.6 sperm/ml in a volume of 3.9 ml.
The progressive motility of the sperm was 65% with normal
morphologies greater than 50%.
Staining--
[0094] Sperm were suspended at 320 million per mL in 30 mL a first
buffer, (TALP described in table 1 at a pH 7.4) with 12 .mu.L of
Hoechst 33342 per 2 mL (48 .mu.M) of stain and incubated for 1 hour
at 34.degree. C. Stained sperm was then placed as 1 mL aliquots in
sample tubes and a 1 mL volume of the appropriate TALP was added.
The same second buffer was used as example 1, namely a modified
5.60 pH TALP. Since the color, and hence the absorption
characteristics of phenol red is pH sensitive, it was made in a
first series with TALP pH 5.60 resulting in a pH of 6.70 (like
example 1) and in a second series the second buffer had a pH of
7.40 (the same buffer as the first buffer, with the addition of the
quenching dyes).
Sorting and Data Acquisition--
[0095] Each of the stained samples was sorted on a MoFlo SX
(Beckman Coulter, USA) as described in Example 6. Screen shots were
taken and the dead gate intensity and the split quality were
measured in the same way described in Example 1 and recorded in
TABLE 14.
TABLE-US-00015 TABLE 14 Phenol Red Yellow 5 Red 40 1250 .mu.M 875
.mu.M 750 .mu.M 500 .mu.M 250 .mu.M 125 .mu.M 62.5 .mu.M Intensity
<30% <30% <30% 43% 48% 63% 53% PV 1.00 1.00 1.00 1.00 1.00
1.00 1.00 Phenol Red (pH 6.70) Yellow 6 1250 .mu.M 875 .mu.M 750
.mu.M 500 .mu.M 250 .mu.M 125 .mu.M 62.5 .mu.M Intensity 41% 45%
55% 67% 70% 79% 50% PV 1.29 1.20 1.25 1.25 1.17 1.00 1.00 Phenol
Red (pH 7.40) 1250 .mu.M 875 .mu.M 750 .mu.M 500 .mu.M 250 .mu.M
125 .mu.M Intensity 43% 47% 56% 66% 76% 85% PV 1.30 1.44 1.46 1.51
1.22 1.27
Results--
[0096] From the additional data on the proportional intensity of
the dead gate it can be seen that it takes about five times as much
yellow food dye No. 5 to get a similar dead gate intensity ratio as
for red food dye No. 40 and yellow food dye No. 6. Furthermore,
phenol red at both of the pH settings tested, is far less capable
of quenching to create a dead gate, requiring twelve times more
than red food dye No. 40 and yellow food dye No. 6. With respect to
the ability to efficiently make a dead population, phenol red does
not appear to be a good candidate, compared to red food dye No. 40
and yellow food dye No. 6 or yellow food dye No. 5. FIG. 7A
illustrates a comparison of the concentrations required to achieve
dead gates with each of the tested dye, combining the date from
example 6 and example 7. It can be seen yellow food dye No. 6 and
red food dye No. 40 perform similarly with respect to creating a
dead gate, but that yellow food dye No. 5 and phenol red require
significantly higher concentrations to affect a gate dead, or
membrane compromised sperm.
[0097] Nonetheless, phenol red was the only of these four dyes
which created a split improvement in this sample. This sample was
"understained" at 12 .mu.L/2 mL, meaning that there was either not
enough Hoechst 33342 for uniform staining. Because of this, the
control samples did not have a split. It was very surprising,
therefore, to see splits emerge in the presence of phenol red.
Also, the quality of the split was improved by the higher pH TALP.
At basic pH, phenol red (pKa 8.0) turn to an ionic alkaline form
and exhibits a pink-red color.
[0098] Keeping in mind a value of 1.00, is the equivalent of no
split, the data in FIG. 7B is surprising in that splits emerge at
all tested concentrations of phenol red. It appears that,
especially at the higher pH configuration, phenol red acts to
reduce noise and may be able to perform as a split enhancing
dye.
Example 7
The Combined Effects of an Improved Dead Quenching Dye and a Split
Enhancing Dye
Collection--
[0099] A single Jersey bull was collected at an initial sperm
concentration 1810.times.10.sup.6 sperm/ml in a volume of 3.9 ml.
The progressive motility of the sperm was 65% with normal
morphologies greater than 50%.
Staining--
[0100] Sperm were stained in previously described first buffer TALP
(pH 7.4) (described in TABLE 1 and in Example 1) at 160 million
sperm/mL with the addition of 48 .mu.M Hoechst 33343 (12 .mu.L/2
mL) and 62 .mu.M yellow food dye No. 6 and incubated for 1 Hour at
34.degree. C. The sperm sample was then concentrated by
centrifugation and resuspended at concentrations of 100, 150, 250,
and 300 million sperm per mL, respectively. Samples were split into
two equal aliquots and in one of each pair of samples, a stock
solution of phenol red was added to make a final phenol red
concentration of 620 .mu.M. Samples at each concentration were
prepared with the dead quencher yellow food dye No. 6 at a
concentration of 62 .mu.M. At each concentration, one control was
compared to the addition of phenol red as a split enhancing dye at
a concentration of 620 .mu.M.
Sorting and Data Acquisition--
[0101] Sorting was performed on a MoFlo SX (Beckman Coulter, USA)
in substantially the same manner described in Example 5. After
calibration, screen shots of sorting histograms were taken and
split quality was measured by the peak to valley ration in the same
way described in Example 5. The resulting data is found in Table
15.
TABLE-US-00016 TABLE 15 Phenol Red Concentration Concentration
Concentration Height of Peak of Cells of Yellow 6 of Phenol Red
Divided by (million per mL) (.mu.M) (.mu.M) Height of Valley 100 62
0 1.26 100 62 620 1.49 150 62 0 1.30 150 62 620 1.34 250 62 0 1.25
250 62 620 1.43 300 62 0 1.23 300 62 620 1.36
Results--
[0102] At each sperm concentration tested the combination of the
split enhancing dye, phenol red, with the dead quenching dye,
yellow food dye No. 6, gives better peak quality than the dead
quencher at the concentrations of yellow food dye No. 6 tested.
Example 8
Phenol Red as an Added Split Enhancing Dye
Collection--
[0103] Two bulls were collected for the Example 8. The Bull 1 was a
Jersey bulls and Bull 2 was a Holstein collected substantially in
the manner described in example 1.
Staining--
[0104] Sperm from Bull 1 extended to 160 million per with a first
buffer, (TALP described in table 1 at a pH 7.4) and divided into
two groups for staining. The first group was stained with 44 .mu.M
Hoechst 33342 and the second group was stained with 60 .mu.M
Hoechst 33342. Similarly, bull 2 was suspended to 160 million per
mL the first buffer, (TALP described in table 1 at a pH 7.4) and
divided into three groups for staining. The first group was stained
with 28 .mu.M Hoechst 33342 and the second group was stained with
44 .mu.M Hoechst 33342 and the third group was stained with 66
.mu.M Hoechst 33342. Each group was incubated for 1 hour at
34.degree. C. and then extended in an equal volume of the second
buffer. The same second buffer was used as Example 1, namely a
modified 5.60 pH TALP.
[0105] The stained samples were each treated with a variety of
quenching dyes and combinations of quenching dyes indicated in
below. Table 16 provides parings of results where phenol red is
investigated in several concentrations, alone and in combination
with red food dye No. 40 and yellow food dye No. 6, for comparison
against a control lacking only the phenol red.
Sorting and Data Acquisition--
[0106] Sorting was performed on a MoFlo SX (Beckman Coulter, USA)
in substantially the same manner described in Example 5. After
calibration, screen shots of sorting histograms were taken and
histograms split quality was measured as a peak to valley ratio in
the same way described in Example 5 with reference to FIG. 4 and
the resulting data is found in Table 16.
Results--
[0107] At each staining level of the DNA selective fluorescent dye,
with both dead quenching dyes (Red 40 and Yellow 6), the addition
of phenol red always improved split quality.
TABLE-US-00017 TABLE 16 Phenol Red as a split enhancing dye Conc
Conc Conc Conc Hoechst 33342 R40 Y6 PR Bull (.mu.M) (.mu.M) (.mu.M)
(.mu.M) PV Bull 1 44 0 0 0 1.44 Bull 1 44 0 0 500 1.97 Bull 1 44 0
50 0 1.20 Bull 1 44 0 50 250 1.52 Bull 1 60 0 0 0 1.60 Bull 1 60 0
0 375 2.38 Bull 1 60 20 0 0 1.62 Bull 1 60 20 0 1200 2.12 Bull 1 60
0 50 0 1.39 Bull 1 60 0 50 375 2.38 Bull 2 28 0 0 0 1.63 Bull 2 28
0 0 375 1.96 Bull 2 28 0 50 0 1.64 Bull 2 28 0 50 375 2.05 Bull 2
44 20 0 0 1.54 Bull 2 44 20 0 375 1.64 Bull 2 44 0 50 0 1.35 Bull 2
44 0 50 225 1.56 Bull 2 44 0 50 375 1.75 Bull 2 60 0 50 0 1.35 Bull
2 60 0 50 375 1.69 Bull 2 60 0 375 0 1.72 Bull 2 60 0 375 375
2.31
Example 9
Red Food Dye No. 3 as an Added Split Enhancing Dye
Collection--
[0108] A single bull was collected for the Example 9 in the same
way described in Example 5.
Staining--
[0109] Sperm from Bull 1 extended to 160 million per with a first
buffer, (TALP described in table 1 at a pH 7.4) and stained with 60
.mu.M Hoechst 33342, as described in Example 1 at 34.degree. C. for
an hour. Each sample was then extended in an equal volume the
second buffer, 5.6 pH modified TALP described in Example 5.
[0110] The second buffer also included either the dead quenching
dye yellow food dye No. 6, or red food dye No. 40 at a
concentration of 60 .mu.M. The second buffer was additionally
treated with concentrations of 25, 50, 100, 150, 300, or 600 .mu.M
of red food dye No. 3, as indicated in Table 6.
Sorting and Data Acquisition--
[0111] Sorting was performed on a MoFlo SX (Beckman Coulter, USA)
in substantially the same manner described in Example 6. After
calibration, screen shots of sorting histograms were taken and the
split quality was measured in terms of peak to valley ratios in the
same way described in Example 5 with reference to FIG. 4 and the
resulting data is found in Table 17.
Results--
[0112] For each sample tested in Table 17, increasing
concentrations or red food dye No. 3 improved the split quality up
to the concentration of 300 .mu.M. At a concentration of 600 .mu.M
the split enhancer red food dye No. 3 still provided improved
splits compared to the control (0 red food dye No. 3), but not
compared to a concentration of 300 .mu.M.
TABLE-US-00018 TABLE 17 Red food dye No. 3 as a split enhancing dye
Conc Conc Conc Conc Hoechst 33342 R40 Y6 R3 Bull (.mu.M) (.mu.M)
(.mu.M) (.mu.M) PV Bull 3 60 0 50 0 1.26 Bull 3 60 0 50 25 1.45
Bull 3 60 0 50 100 1.38 Bull 3 60 0 50 150 1.41 Bull 3 60 0 50 300
1.66 Bull 3 60 0 50 600 1.31 Bull 3 60 0 50 0 1.32 Bull 3 60 0 50
50 1.33 Bull 3 60 0 50 100 1.55 Bull 3 60 0 50 300 1.68 Bull 3 60 0
50 600 1.42 Bull 3 60 50 0 0 1.44 Bull 3 60 50 0 50 1.63 Bull 3 60
50 0 100 1.65 Bull 3 60 50 0 200 1.78 Bull 3 60 50 0 300 2.15
Example 10
Split Enhancing Dyes at Various Concentrations
Collection
[0113] Eight bulls were collected, including 4 Jersey bulls, 3
Holstein bulls and one mixed dairy-breed. The ejaculates were
collected at concentrations ranging from 1700.times.10.sup.6
sperm/ml to 1100.times.10.sup.6 sperm/ml and all had progressive
motility of a least 60%.
Staining--
[0114] Sperm from each bull was extended to 160 million per ml with
a first buffer, (TALP described in table 1 at a pH 7.4) and stained
with 64 .mu.M (16 .mu.L/2 mL) Hoechst 33342 at 34.degree. C.
Additionally, Phenol Red, Red Food Dye No. 2, Red Food Dye No. 3,
and Red Food Dye No. 4, were each tested as split enhancing dyes in
the first buffer at concentrations of 15 .mu.M, 45 .mu.M and 125
.mu.M. For each bull, each concentration of each dye was incubated
for periods of 30 minutes, 45 minutes, 60 minutes, and 75 minutes
were utilized before a second buffer with an additional dye was
applied.
[0115] Each sample was then extended in an equal volume of a second
buffer which comprised a 5.5 pH modified TALP having 25 .mu.M
yellow food dye No. 6 (acting as a dead quenching dye) in addition
to the split enhancing dye provided in the first buffer. The second
buffer was applied to every sample at 30 minutes, 45 minutes, 60
minutes, and 75 minutes. A control was additionally taken without
any split enhancing dye for every bull at every time interval.
Sorting and Data Acquisition--
[0116] Sorting was performed on a MoFlo SX (Beckman Coulter, USA)
in substantially the same manner described in Example 5. After
calibration, screen shots of sorting histograms were taken and
split quality was measured by peak to valley ratios in the same way
described in Example 5 with reference to FIG. 4 and the resulting
data, averaged over all 8 bulls, is found in Tables 18-21.
Additionally, screen shots of bivariate plots were taken to measure
the added dead quenching capacity of the mixed dead quenching and
split enhancing dyes.
Results--
[0117] Referring to Table 18, red food dye No. 2 did not provide a
split enhancing, or noise reducing effect. Instead, averaged over
the 8 bulls, every concentration of Red Food dye no. 2 resulted in
a reduced peak to valley ratio, as compared to a control. Red food
dye No. 2 did, however, provide a strong dead quenching capacity as
seen in FIG. 8.
[0118] Referring to Table 19, red food dye No. 3, on average,
provided initial split enhancements at 15 .mu.M and 45 .mu.M, but
the control was as good as 45 .mu.M after 60 minutes and as good as
15 .mu.M after 75 minutes.
[0119] Referring to Table 20, Phenol Red provided consistent split
improvements at all concentrations after 30 minutes. This
improvement may provide a means for shortening incubation times, or
may simply provide for higher throughput and higher purity in sex
sorting protocols.
[0120] Referring to Table 21, red food dye No. 4 provides distinct
improvements at all concentrations and at all times. Referring to
FIG. 9, the split enhancement can be at each of 15 .mu.M, 45 .mu.M
and 125 .mu.M, particularly at 45 minutes and beyond. Red Food dye
no. 4 may provide noise reduction and split enhancement at lower
concentrations approaching 0 .mu.M and does not show any sign of
tailing off at the top end of the range tested. Red food dye No. 4
provided more consistent improvements across concentrations and
times than phenol red and it is believed may continue to provide
benefits in the ranges in which Phenol Red was tested in Example 9,
such as concentrations as high as 1200 .mu.M.
[0121] At the highest tested concentration red food dye No. 4
additionally provided a significant increase in quenching the dead
subpopulation. Red food dye No. 4 may provide for a robust split
enhancing dye over a large range of concentrations, and more
provide the added benefit of reducing the amount of dead quenching
dye required for sorting sperm.
TABLE-US-00019 TABLE 18 Red Food Dye No. 2 - Average 8 bulls 30 Min
45 Min 60 Min 75 Min Control- 0 .mu.M Red 2 1.07 1.23 1.58 1.80 15
.mu.M Red 2 1.06 1.15 1.54 1.73 45 .mu.M Red 2 1.00 1.05 1.12 1.38
125 .mu.M Red 2 1.00 1.00 1.00 1.00
TABLE-US-00020 TABLE 19 Red Food Dye No. 3 - Average 8 bulls 30 Min
45 Min 60 Min 75 Min Control- 0 .mu.M Red 3 1.07 1.23 1.58 1.80 15
.mu.M Red 3 1.05 1.43 1.78 1.79 45 .mu.M Red 3 1.05 1.36 1.58 1.60
125 .mu.M Red 3 1.00 1.02 1.10 1.32
TABLE-US-00021 TABLE 20 Phenol Red - Average 8 bulls 30 Min 45 Min
60 Min 75 Min Control- 0 .mu.M Red 3 1.07 1.23 1.58 1.80 15 .mu.M
Red 3 1.14 1.30 1.77 1.87 45 .mu.M Red 3 1.01 1.36 1.68 1.81 125
.mu.M Red 3 1.08 1.42 1.73 1.84
TABLE-US-00022 TABLE 21 Red Food Dye No. 4 - Average 8 bulls 30 Min
45 Min 60 Min 75 Min Control- 0 .mu.M Red 4 1.07 1.23 1.58 1.80 15
.mu.M Red 4 1.09 1.44 1.79 1.91 45 .mu.M Red 4 1.18 1.50 1.76 1.94
125 .mu.M Red 4 1.13 1.45 1.81 1.95
[0122] As can be easily understood from the foregoing, the basic
concepts of the present invention may be embodied in a variety of
ways. The invention involves numerous and varied embodiments of
staining sperm for sex sorting including, but not limited to, the
best mode of the invention.
[0123] As such, the particular embodiments or elements of the
invention disclosed by the description or shown in the figures or
tables accompanying this application are not intended to be
limiting, but rather exemplary of the numerous and varied
embodiments generically encompassed by the invention or equivalents
encompassed with respect to any particular element thereof. In
addition, the specific description of a single embodiment or
element of the invention may not explicitly describe all
embodiments or elements possible; many alternatives are implicitly
disclosed by the description and figures.
[0124] It should be understood that each element of an apparatus or
each step of a method may be described by an apparatus term or
method term. Such terms can be substituted where desired to make
explicit the implicitly broad coverage to which this invention is
entitled. As but one example, it should be understood that all
steps of a method may be disclosed as an action, a means for taking
that action, or as an element which causes that action. Similarly,
each element of an apparatus may be disclosed as the physical
element or the action which that physical element facilitates. As
but one example, the disclosure of "sorter" should be understood to
encompass disclosure of the act of "sorting"--whether explicitly
discussed or not--and, conversely, were there effectively
disclosure of the act of "sorting", such a disclosure should be
understood to encompass disclosure of a "sorter" and even a "means
for sorting." Such alternative terms for each element or step are
to be understood to be explicitly included in the description.
[0125] In addition, as to each term used it should be understood
that unless its utilization in this application is inconsistent
with such interpretation, common dictionary definitions should be
understood to be included in the description for each term as
contained in the Random House Webster's Unabridged Dictionary,
second edition, each definition hereby incorporated by
reference.
[0126] Moreover, for the purposes of the present invention, the
term "a" or "an" entity refers to one or more of that entity. As
such, the terms "a" or "an", "one or more" and "at least one" can
be used interchangeably herein.
[0127] All numeric values herein are assumed to be modified by the
term "about", whether or not explicitly indicated. For the purposes
of the present invention, ranges may be expressed as from "about"
one particular value to "about" another particular value. When such
a range is expressed, another embodiment includes from the one
particular value to the other particular value. The recitation of
numerical ranges by endpoints includes all the numeric values
subsumed within that range. A numerical range of one to five
includes for example the numeric values 1, 1.5, 2, 2.75, 3, 3.80,
4, 5, and so forth. It will be further understood that the
endpoints of each of the ranges are significant both in relation to
the other endpoint, and independently of the other endpoint. When a
value is expressed as an approximation by use of the antecedent
"about," it will be understood that the particular value forms
another embodiment.
[0128] The background section of this patent application provides a
statement of the field of endeavor to which the invention pertains.
This section may also incorporate or contain paraphrasing of
certain United States patents, patent applications, publications,
or subject matter of the claimed invention useful in relating
information, problems, or concerns about the state of technology to
which the invention is drawn toward. It is not intended that any
United States patent, patent application, publication, statement or
other information cited or incorporated herein be interpreted,
construed or deemed to be admitted as prior art with respect to the
invention.
[0129] The claims set forth in this specification, if any, are
hereby incorporated by reference as part of this description of the
invention, and the applicant expressly reserves the right to use
all of or a portion of such incorporated content of such claims as
additional description to support any of or all of the claims or
any element or component thereof, and the applicant further
expressly reserves the right to move any portion of or all of the
incorporated content of such claims or any element or component
thereof from the description into the claims or vice versa as
necessary to define the matter for which protection is sought by
this application or by any subsequent application or continuation,
division, or continuation-in-part application thereof, or to obtain
any benefit of, reduction in fees pursuant to, or to comply with
the patent laws, rules, or regulations of any country or treaty,
and such content incorporated by reference shall survive during the
entire pendency of this application including any subsequent
continuation, division, or continuation-in-part application thereof
or any reissue or extension thereon.
* * * * *