B. Pukazhenthi - Academia.edu (original) (raw)

Papers by B. Pukazhenthi

Research paper thumbnail of 32 Challenges and considerations for biobanking for zoos and aquaria: a mammoth undertaking

Reproduction, Fertility and Development

Research paper thumbnail of The steroid metabolome of pregnancy, insights into the maintenance of pregnancy and evolution of reproductive traits

Molecular and Cellular Endocrinology, 2021

Modes of mammalian reproduction are diverse and not always conserved among related species. Proge... more Modes of mammalian reproduction are diverse and not always conserved among related species. Progesterone is universally required to supports pregnancy but sites of synthesis and metabolic pathways vary widely. The steroid metabolome of mid- to late gestation was characterized, focusing on 5α-reduced pregnanes in species representing the Perissodactyla, Cetartiodactyla and Carnivora using mass spectrometry. Metabolomes and steroidogenic enzyme orthologue sequences were used in heirarchial analyses. Steroid metabolite profiles were similar within orders, whales within cetartiodactyls for instance, but with notable exceptions such as rhinoceros clustering with goats, and tapirs with pigs. Steroidogenic enzyme sequence clustering reflected expected evolutionary relationships but once again with exceptions. Human sequences (expected outgroups) clustered with perissodactyl CYP11A1, CYP17A1 and SRD5A1 gene orthologues, forming outgroups only for HSD17B1 and SRD5A2. Spotted hyena CYP19A1 clustered within the Perissodactyla, between rhinoceros and equid orthologues, whereas CYP17A1 clustered within the Carnivora. This variability highlights the random adoption of divergent physiological strategies as pregnancy evolved among genetically similar species.

Research paper thumbnail of Impact of ethanol and heat stress–dependent effect of ultra-diluted Arnica montana 6 cH on in vitro embryo production in cattle

Theriogenology, 2021

This study evaluated the effect of adding ultra-diluted and dynamized Arnica montana 6 cH, and it... more This study evaluated the effect of adding ultra-diluted and dynamized Arnica montana 6 cH, and its vehicle (0.3% ethanol) to the in vitro maturation (IVM) medium, in the absence (experiment 1) or presence (experiment 2) of heat stress (HS), on bovine oocyte maturation and in vitro embryo production (IVEP). In experiment 1 (n = 902 cumulus oocyte complexes, COCs), the treatments were 1) IVM medium (Control treatment), 2) IVM medium + 0.3% ethanol, and 3) IVM medium + Arnica montana 6 cH. In experiment 2 (n = 1064 COCs), the treatments were 1) IVM medium without HS, 2) IVM medium under HS, 3) IVM medium + ethanol under HS, and 4) IVM medium + Arnica montana under HS. In the absence of HS (experiment 1), the addition of Arnica montana to the IVM medium had a deleterious effect on the IVEP (cleavage and blastocyst rates) and the total cell number/blastocysts. On the other hand, ethanol (0.3%) increased IVEP in relation to the Control and Arnica montana treatments. However, in the presence of HS during IVM (experiment 2), the addition of ethanol or Arnica montana increased IVEP when compared to the HS treatment alone, and the Arnica montana treatment resulted in greater total cell number/blastocysts compared to the other treatments. In conclusion, this study showed for the first time that the negative or positive effect of Arnica montana 6 cH on IVEP depends on the culture condition (i.e., absence or presence of HS during IVM). On the other hand, ethanol showed beneficial and consistent results on IVEP regardless of exposure to HS.

Research paper thumbnail of Characterization of Ovarian Steroid Patterns in Female African Lions (Panthera leo), and the Effects of Contraception on Reproductive Function

Research paper thumbnail of Challenges in cryopreservation of clouded leopard (Neofelis nebulosa) spermatozoa

Research paper thumbnail of Spermatology for understanding, managing and conserving rare species

Reproduction, Fertility and Development, 1995

Most conventional spermatology research involves common mammalian species including livestock, la... more Most conventional spermatology research involves common mammalian species including livestock, laboratory animals and humans. Yet, there are more than 4500 mammalian species inhabiting the planet for which little is known about basic reproductive biology, including sperm characteristics and function. This information is important, not just as adjunct knowledge, but because the majority of these species are threatened with extinction, largely due to human-induced pressures. The field of conservation is changing rapidly, and global cooperation is emerging among a variety of wildlife enthusiasts, ranging from management authorities of nature reserves to curators of rare zoological collections. Conservation progress depends on systematic, multidisciplinary research first to answer basic questions, with new data then applied to endangered species management plans. The reproductive physiologist is a crucial component of this scheme. Reproduction is the essence of species survival, and eno...

Research paper thumbnail of Creatine phosphokinase in domestic cat epididymal spermatozoa

Molecular Reproduction and Development, 2002

Mammalian spermatozoa that have not completed final testicular sperm maturation have residual cyt... more Mammalian spermatozoa that have not completed final testicular sperm maturation have residual cytoplasm and increased creatine phosphokinase (CK) content. This study determined: (1) if CK could be detected by immunostaining cat spermatozoa from the caput, corpus, and cauda epididymis, (2) fluctuations in the proportions of spermatozoa with mature or immature CK-staining patterns during epididymal sperm transit, and (3) how well sperm maturity (as determined by a CK marker) correlated with testicular or epididymal dysfunctions associated with morphological sperm abnormalities. One epididymis was collected from each of 37 cats after orchiectomy and processed immediately to allow sperm morphology evaluations on a 'regional' basis. Sperm released from the contralateral epididymis were evaluated for motility, sperm membrane integrity, and immunostaining with CK-B antibodies. Proportions of spermatozoa with malformed or detached heads, proximal droplets and acrosomal or midpiece abnormalities decreased (P < 0.05) from the caput to the cauda epididymis. In contrast, proportions of spermatozoa that were motile, membrane-intact or with flagellar abnormalities or distal droplets increased (P < 0.05) from the caput to cauda region. Percentages of spermatozoa with an immature CK-staining pattern also decreased (P < 0.05) with epididymal transit (which differs from that reported for the human and stallion). There was no correlation (P > 0.05) between sperm morphology and the CK-staining patterns. In summary, the results reveal that some specific sperm malformations in the domestic cat are of testicular origin, whereas others develop during epididymal transit.

Research paper thumbnail of A review of the reproductive biology and breeding management of tapirs

Integrative Zoology, 2013

Research paper thumbnail of 124 Pretreatment of Dama gazelle (Nanger dama ruficollis) spermatozoa with cholesterol-loaded cyclodextrins improves cryosurvival

Research paper thumbnail of Update: Genetic relatedness of critically endangered dama gazelle populations in the wild and captivity

Research paper thumbnail of Dietary Supplementation of Algae-derived Omega-3 Fatty Acids Influences Endometrial and Conceptus Transcript Profiles in Mares

Journal of Equine Veterinary Science

Research paper thumbnail of 229 Long-Term Propagation and Cryopreservation of Cat Spermatogonial Stem Cells

Reproduction, Fertility and Development, 2016

Spermatogonial stem cells (SSC) are unique adult stem cells that reside within the seminiferous t... more Spermatogonial stem cells (SSC) are unique adult stem cells that reside within the seminiferous tubules of the testis. As stem cells, SSC maintain the ability to self-replicate, providing a potentially unlimited supply of cells and an alternate source for preservation of the male genome. While self-renewing, long-term SSC culture has been achieved in mice, there is virtually no information regarding culture requirements of felid SSC. Therefore, the objectives of this study were to (1) evaluate the ability of 3 feeder cell lines to support germ cell colony establishment in domestic cats (Felis catus), and (2) assess long-term culture using the best feeder(s). Cells isolated enzymatically from peripubertal cat testes (n = 4) and enriched by differential plating were cultured on mouse embryonic fibroblasts (STO line), mouse-derived C166 endothelial cells, and primary cat fetal fibroblasts (cFF). Colony morphology was assessed every other day and immunocytochemistry (ICC) was performed ...

Research paper thumbnail of 120 Impact of Season on Seminal Characteristics and Sperm Cryopreservation in the Tufted Deer (Elaphodus Cephalophus)

Reproduction, Fertility and Development, 2016

The Tufted deer (Elaphodus cephalophus), a small deer species native to China, is listed as near ... more The Tufted deer (Elaphodus cephalophus), a small deer species native to China, is listed as near threatened on the IUCN Red List and >70 animals are managed in North American zoos as a hedge against extinction. In this study, we 1) characterized the seminal traits, 2) assessed the impact of season on ejaculate traits and testosterone level, and 3) examined sperm sensitivity to cryopreservation. Semen (24 ejaculates) were obtained from five males (1–2 ejaculates/male per season) by electro-ejaculation and evaluated for volume, osmolality, pH as well as sperm concentration, motility (%M), forward progression (FP, scale = 0–5) and acrosomal integrity (%AI). Ejaculates were divided into two aliquots and cryopreserved (4% vol/vol glycerol final concentration; 50–200 × 106 sperm mL–1) over liquid nitrogen vapor using Beltsville extender (BF5F; Howard et al. 1986) or Triladyl® (TRIL; Minitüb GmbH, Germany) extender. Sperm motility and %AI were assessed immediately (subjective) upon thaw...

Research paper thumbnail of 130 Effect of dietary omega-3 supplementation on equine endometrial and embryonic gene expression

Journal of Equine Veterinary Science, 2015

Research paper thumbnail of A protocol to correct for intra- and interspecific variation in tail hair growth to align isotope signatures of segmentally cut tail hair to a common time line

Rapid Communications in Mass Spectrometry, 2015

Research paper thumbnail of Challenges in cryopreserving endangered mammal spermatozoa: morphology and the value of acrosomal integrity as markers of cryo-survival

Society of Reproduction and Fertility supplement, 2007

The science of cryobiology is essential to the effective, practical use of semen for assisted bre... more The science of cryobiology is essential to the effective, practical use of semen for assisted breeding to help manage small populations of rare wildlife species. In this review, we describe challenges associated with cryopreserving gametes from wild fauna. Based on more than 25 years of experience across a diversity of mammals, it appears that the primary driving force dictating cryo-survival of a spermatozoon is its initial pre-freeze quality and morphology, especially having a morphologically normal, intact acrosome. This assertion is supported through extensive studies of three animal groups that routinely ejaculate semen containing (1) normal sperm/acrosomal quality (examples, Eld's deer, Cervus eldi and giant panda, Ailuropoda melanoleuca), (2) normal acrosomal quality, but from teratospermic donors (>70% pleiomorphic sperm; cheetah, Acinonyx jubatus and black-footed ferret, Mustela nigripes) and (3) abnormal acrosomal quality and general teratospermia (clouded leopard, ...

Research paper thumbnail of The phenomenon and significance of teratospermia in felids

Journal of reproduction and fertility. Supplement, 2001

The common domestic cat is an important research model for endangered felids, as well as for stud... more The common domestic cat is an important research model for endangered felids, as well as for studying genetic dysfunctions, infectious diseases and infertility in humans. Especially significant is the trait of teratospermia (ejaculation of < 40% morphologically normal spermatozoa) that commonly occurs in about 70% of the felid species or subspecies studied to date. Teratospermia, discovered more than two decades ago in the cheetah, is important: (i) for understanding the significance of sperm form and function; and (ii) because this condition is common in human males. It is apparent from IVF that deformed spermatozoa from teratospermic felids do not fertilize oocytes. However, the inability of spermatozoa from teratospermic males to bind, penetrate and decondense in the cytoplasm of the oocyte is not limited to malformed cells alone. Normal shaped spermatozoa from teratospermic males have reduced functional capacity. IVF results have consistently revealed a direct correlation bet...

Research paper thumbnail of Regulation of sperm function by protein tyrosine phosphorylation in diverse wild felid species

Journal of andrology

Protein tyrosine phosphorylation is associated with sperm capacitation and the acrosome reaction ... more Protein tyrosine phosphorylation is associated with sperm capacitation and the acrosome reaction in several mammalian species. Changes in phosphorylation of a 95-kDa protein in human, mouse, and domestic cat spermatozoa are known to be influenced by capacitation and exposure to zona pellucida (ZP) proteins. We previously reported diminished phosphorylation of 95- and 160-kDa proteins in spermatozoa from teratospermic cats, compared with normospermic domestic cats. To determine if these proteins and mechanisms are present in other species in the phenotypically diverse Felidae family, we examined the relationship between tyrosine-phosphorylated sperm proteins and sperm morphology in the leopard cat (approximately 65% normal sperm/ejaculate), tiger (approximately 65%), clouded leopard (approximately 15%), and cheetah (approximately 30%). Furthermore, we investigated the involvement of cyclic adenosine monophosphate (cAMP) in the regulation of sperm protein tyrosine phosphorylation. Spe...

Research paper thumbnail of Role of sulfhydryl groups in the function of glucosidase I from mammary gland

The Journal of biological chemistry, Jan 25, 1993

Glucosidase I initiates the processing of asparagine-linked glycoproteins by excising the distal ... more Glucosidase I initiates the processing of asparagine-linked glycoproteins by excising the distal alpha 1,2-linked glucosyl residue from the Glc3Man9GlcNAc2 oligosaccharide, soon after its en bloc transfer from the lipid-linked donor to the nascent polypeptide. 1-Deoxynojirimycin, an analog of D-glucose, is a potent competitive inhibitor of the enzyme. Sulfhydryl-seeking reagents also strongly inhibit the enzyme, implying the involvement of an -SH group in its activity. To test this hypothesis, glucosidase I was purified from the rat mammary gland and its active site was loaded with 1-deoxynojirimycin, to protect such a group(s), while -SH groups on the remaining surface of the enzyme were blocked with N-ethylmaleimide or para-chloromercuriphenylsulfonic acid. Deoxynojirimycin was removed by dialysis to expose the active site -SH group(s). This group(s) was then tagged with 3-(N-maleimidopropionyl)biocytin (MPB) and detected with 125I-streptavidin on Western blots. A series of experi...

Research paper thumbnail of The Rare Addra Gazelle (Gazella Dama Ruficollis) Produces Viable Spermic Ejaculates That Tolerate Cryopreservation

Research paper thumbnail of 32 Challenges and considerations for biobanking for zoos and aquaria: a mammoth undertaking

Reproduction, Fertility and Development

Research paper thumbnail of The steroid metabolome of pregnancy, insights into the maintenance of pregnancy and evolution of reproductive traits

Molecular and Cellular Endocrinology, 2021

Modes of mammalian reproduction are diverse and not always conserved among related species. Proge... more Modes of mammalian reproduction are diverse and not always conserved among related species. Progesterone is universally required to supports pregnancy but sites of synthesis and metabolic pathways vary widely. The steroid metabolome of mid- to late gestation was characterized, focusing on 5α-reduced pregnanes in species representing the Perissodactyla, Cetartiodactyla and Carnivora using mass spectrometry. Metabolomes and steroidogenic enzyme orthologue sequences were used in heirarchial analyses. Steroid metabolite profiles were similar within orders, whales within cetartiodactyls for instance, but with notable exceptions such as rhinoceros clustering with goats, and tapirs with pigs. Steroidogenic enzyme sequence clustering reflected expected evolutionary relationships but once again with exceptions. Human sequences (expected outgroups) clustered with perissodactyl CYP11A1, CYP17A1 and SRD5A1 gene orthologues, forming outgroups only for HSD17B1 and SRD5A2. Spotted hyena CYP19A1 clustered within the Perissodactyla, between rhinoceros and equid orthologues, whereas CYP17A1 clustered within the Carnivora. This variability highlights the random adoption of divergent physiological strategies as pregnancy evolved among genetically similar species.

Research paper thumbnail of Impact of ethanol and heat stress–dependent effect of ultra-diluted Arnica montana 6 cH on in vitro embryo production in cattle

Theriogenology, 2021

This study evaluated the effect of adding ultra-diluted and dynamized Arnica montana 6 cH, and it... more This study evaluated the effect of adding ultra-diluted and dynamized Arnica montana 6 cH, and its vehicle (0.3% ethanol) to the in vitro maturation (IVM) medium, in the absence (experiment 1) or presence (experiment 2) of heat stress (HS), on bovine oocyte maturation and in vitro embryo production (IVEP). In experiment 1 (n = 902 cumulus oocyte complexes, COCs), the treatments were 1) IVM medium (Control treatment), 2) IVM medium + 0.3% ethanol, and 3) IVM medium + Arnica montana 6 cH. In experiment 2 (n = 1064 COCs), the treatments were 1) IVM medium without HS, 2) IVM medium under HS, 3) IVM medium + ethanol under HS, and 4) IVM medium + Arnica montana under HS. In the absence of HS (experiment 1), the addition of Arnica montana to the IVM medium had a deleterious effect on the IVEP (cleavage and blastocyst rates) and the total cell number/blastocysts. On the other hand, ethanol (0.3%) increased IVEP in relation to the Control and Arnica montana treatments. However, in the presence of HS during IVM (experiment 2), the addition of ethanol or Arnica montana increased IVEP when compared to the HS treatment alone, and the Arnica montana treatment resulted in greater total cell number/blastocysts compared to the other treatments. In conclusion, this study showed for the first time that the negative or positive effect of Arnica montana 6 cH on IVEP depends on the culture condition (i.e., absence or presence of HS during IVM). On the other hand, ethanol showed beneficial and consistent results on IVEP regardless of exposure to HS.

Research paper thumbnail of Characterization of Ovarian Steroid Patterns in Female African Lions (Panthera leo), and the Effects of Contraception on Reproductive Function

Research paper thumbnail of Challenges in cryopreservation of clouded leopard (Neofelis nebulosa) spermatozoa

Research paper thumbnail of Spermatology for understanding, managing and conserving rare species

Reproduction, Fertility and Development, 1995

Most conventional spermatology research involves common mammalian species including livestock, la... more Most conventional spermatology research involves common mammalian species including livestock, laboratory animals and humans. Yet, there are more than 4500 mammalian species inhabiting the planet for which little is known about basic reproductive biology, including sperm characteristics and function. This information is important, not just as adjunct knowledge, but because the majority of these species are threatened with extinction, largely due to human-induced pressures. The field of conservation is changing rapidly, and global cooperation is emerging among a variety of wildlife enthusiasts, ranging from management authorities of nature reserves to curators of rare zoological collections. Conservation progress depends on systematic, multidisciplinary research first to answer basic questions, with new data then applied to endangered species management plans. The reproductive physiologist is a crucial component of this scheme. Reproduction is the essence of species survival, and eno...

Research paper thumbnail of Creatine phosphokinase in domestic cat epididymal spermatozoa

Molecular Reproduction and Development, 2002

Mammalian spermatozoa that have not completed final testicular sperm maturation have residual cyt... more Mammalian spermatozoa that have not completed final testicular sperm maturation have residual cytoplasm and increased creatine phosphokinase (CK) content. This study determined: (1) if CK could be detected by immunostaining cat spermatozoa from the caput, corpus, and cauda epididymis, (2) fluctuations in the proportions of spermatozoa with mature or immature CK-staining patterns during epididymal sperm transit, and (3) how well sperm maturity (as determined by a CK marker) correlated with testicular or epididymal dysfunctions associated with morphological sperm abnormalities. One epididymis was collected from each of 37 cats after orchiectomy and processed immediately to allow sperm morphology evaluations on a &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;regional&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39; basis. Sperm released from the contralateral epididymis were evaluated for motility, sperm membrane integrity, and immunostaining with CK-B antibodies. Proportions of spermatozoa with malformed or detached heads, proximal droplets and acrosomal or midpiece abnormalities decreased (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.05) from the caput to the cauda epididymis. In contrast, proportions of spermatozoa that were motile, membrane-intact or with flagellar abnormalities or distal droplets increased (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.05) from the caput to cauda region. Percentages of spermatozoa with an immature CK-staining pattern also decreased (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.05) with epididymal transit (which differs from that reported for the human and stallion). There was no correlation (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt; 0.05) between sperm morphology and the CK-staining patterns. In summary, the results reveal that some specific sperm malformations in the domestic cat are of testicular origin, whereas others develop during epididymal transit.

Research paper thumbnail of A review of the reproductive biology and breeding management of tapirs

Integrative Zoology, 2013

Research paper thumbnail of 124 Pretreatment of Dama gazelle (Nanger dama ruficollis) spermatozoa with cholesterol-loaded cyclodextrins improves cryosurvival

Research paper thumbnail of Update: Genetic relatedness of critically endangered dama gazelle populations in the wild and captivity

Research paper thumbnail of Dietary Supplementation of Algae-derived Omega-3 Fatty Acids Influences Endometrial and Conceptus Transcript Profiles in Mares

Journal of Equine Veterinary Science

Research paper thumbnail of 229 Long-Term Propagation and Cryopreservation of Cat Spermatogonial Stem Cells

Reproduction, Fertility and Development, 2016

Spermatogonial stem cells (SSC) are unique adult stem cells that reside within the seminiferous t... more Spermatogonial stem cells (SSC) are unique adult stem cells that reside within the seminiferous tubules of the testis. As stem cells, SSC maintain the ability to self-replicate, providing a potentially unlimited supply of cells and an alternate source for preservation of the male genome. While self-renewing, long-term SSC culture has been achieved in mice, there is virtually no information regarding culture requirements of felid SSC. Therefore, the objectives of this study were to (1) evaluate the ability of 3 feeder cell lines to support germ cell colony establishment in domestic cats (Felis catus), and (2) assess long-term culture using the best feeder(s). Cells isolated enzymatically from peripubertal cat testes (n = 4) and enriched by differential plating were cultured on mouse embryonic fibroblasts (STO line), mouse-derived C166 endothelial cells, and primary cat fetal fibroblasts (cFF). Colony morphology was assessed every other day and immunocytochemistry (ICC) was performed ...

Research paper thumbnail of 120 Impact of Season on Seminal Characteristics and Sperm Cryopreservation in the Tufted Deer (Elaphodus Cephalophus)

Reproduction, Fertility and Development, 2016

The Tufted deer (Elaphodus cephalophus), a small deer species native to China, is listed as near ... more The Tufted deer (Elaphodus cephalophus), a small deer species native to China, is listed as near threatened on the IUCN Red List and >70 animals are managed in North American zoos as a hedge against extinction. In this study, we 1) characterized the seminal traits, 2) assessed the impact of season on ejaculate traits and testosterone level, and 3) examined sperm sensitivity to cryopreservation. Semen (24 ejaculates) were obtained from five males (1–2 ejaculates/male per season) by electro-ejaculation and evaluated for volume, osmolality, pH as well as sperm concentration, motility (%M), forward progression (FP, scale = 0–5) and acrosomal integrity (%AI). Ejaculates were divided into two aliquots and cryopreserved (4% vol/vol glycerol final concentration; 50–200 × 106 sperm mL–1) over liquid nitrogen vapor using Beltsville extender (BF5F; Howard et al. 1986) or Triladyl® (TRIL; Minitüb GmbH, Germany) extender. Sperm motility and %AI were assessed immediately (subjective) upon thaw...

Research paper thumbnail of 130 Effect of dietary omega-3 supplementation on equine endometrial and embryonic gene expression

Journal of Equine Veterinary Science, 2015

Research paper thumbnail of A protocol to correct for intra- and interspecific variation in tail hair growth to align isotope signatures of segmentally cut tail hair to a common time line

Rapid Communications in Mass Spectrometry, 2015

Research paper thumbnail of Challenges in cryopreserving endangered mammal spermatozoa: morphology and the value of acrosomal integrity as markers of cryo-survival

Society of Reproduction and Fertility supplement, 2007

The science of cryobiology is essential to the effective, practical use of semen for assisted bre... more The science of cryobiology is essential to the effective, practical use of semen for assisted breeding to help manage small populations of rare wildlife species. In this review, we describe challenges associated with cryopreserving gametes from wild fauna. Based on more than 25 years of experience across a diversity of mammals, it appears that the primary driving force dictating cryo-survival of a spermatozoon is its initial pre-freeze quality and morphology, especially having a morphologically normal, intact acrosome. This assertion is supported through extensive studies of three animal groups that routinely ejaculate semen containing (1) normal sperm/acrosomal quality (examples, Eld's deer, Cervus eldi and giant panda, Ailuropoda melanoleuca), (2) normal acrosomal quality, but from teratospermic donors (>70% pleiomorphic sperm; cheetah, Acinonyx jubatus and black-footed ferret, Mustela nigripes) and (3) abnormal acrosomal quality and general teratospermia (clouded leopard, ...

Research paper thumbnail of The phenomenon and significance of teratospermia in felids

Journal of reproduction and fertility. Supplement, 2001

The common domestic cat is an important research model for endangered felids, as well as for stud... more The common domestic cat is an important research model for endangered felids, as well as for studying genetic dysfunctions, infectious diseases and infertility in humans. Especially significant is the trait of teratospermia (ejaculation of < 40% morphologically normal spermatozoa) that commonly occurs in about 70% of the felid species or subspecies studied to date. Teratospermia, discovered more than two decades ago in the cheetah, is important: (i) for understanding the significance of sperm form and function; and (ii) because this condition is common in human males. It is apparent from IVF that deformed spermatozoa from teratospermic felids do not fertilize oocytes. However, the inability of spermatozoa from teratospermic males to bind, penetrate and decondense in the cytoplasm of the oocyte is not limited to malformed cells alone. Normal shaped spermatozoa from teratospermic males have reduced functional capacity. IVF results have consistently revealed a direct correlation bet...

Research paper thumbnail of Regulation of sperm function by protein tyrosine phosphorylation in diverse wild felid species

Journal of andrology

Protein tyrosine phosphorylation is associated with sperm capacitation and the acrosome reaction ... more Protein tyrosine phosphorylation is associated with sperm capacitation and the acrosome reaction in several mammalian species. Changes in phosphorylation of a 95-kDa protein in human, mouse, and domestic cat spermatozoa are known to be influenced by capacitation and exposure to zona pellucida (ZP) proteins. We previously reported diminished phosphorylation of 95- and 160-kDa proteins in spermatozoa from teratospermic cats, compared with normospermic domestic cats. To determine if these proteins and mechanisms are present in other species in the phenotypically diverse Felidae family, we examined the relationship between tyrosine-phosphorylated sperm proteins and sperm morphology in the leopard cat (approximately 65% normal sperm/ejaculate), tiger (approximately 65%), clouded leopard (approximately 15%), and cheetah (approximately 30%). Furthermore, we investigated the involvement of cyclic adenosine monophosphate (cAMP) in the regulation of sperm protein tyrosine phosphorylation. Spe...

Research paper thumbnail of Role of sulfhydryl groups in the function of glucosidase I from mammary gland

The Journal of biological chemistry, Jan 25, 1993

Glucosidase I initiates the processing of asparagine-linked glycoproteins by excising the distal ... more Glucosidase I initiates the processing of asparagine-linked glycoproteins by excising the distal alpha 1,2-linked glucosyl residue from the Glc3Man9GlcNAc2 oligosaccharide, soon after its en bloc transfer from the lipid-linked donor to the nascent polypeptide. 1-Deoxynojirimycin, an analog of D-glucose, is a potent competitive inhibitor of the enzyme. Sulfhydryl-seeking reagents also strongly inhibit the enzyme, implying the involvement of an -SH group in its activity. To test this hypothesis, glucosidase I was purified from the rat mammary gland and its active site was loaded with 1-deoxynojirimycin, to protect such a group(s), while -SH groups on the remaining surface of the enzyme were blocked with N-ethylmaleimide or para-chloromercuriphenylsulfonic acid. Deoxynojirimycin was removed by dialysis to expose the active site -SH group(s). This group(s) was then tagged with 3-(N-maleimidopropionyl)biocytin (MPB) and detected with 125I-streptavidin on Western blots. A series of experi...

Research paper thumbnail of The Rare Addra Gazelle (Gazella Dama Ruficollis) Produces Viable Spermic Ejaculates That Tolerate Cryopreservation