34 results on '"Roberts KP"'
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2. Neuronal GPCR NMUR-1 regulates energy homeostasis in response to pathogen infection.
- Author
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Wibisono P, Liu Y, Roberts KP, Baluya D, and Sun J
- Abstract
A key question in current immunology is how the innate immune system generates high levels of specificity. Our previous study in Caenorhabditis elegans revealed that NMUR-1, a neuronal G protein-coupled receptor homologous to mammalian receptors for the neuropeptide neuromedin U (NMU), regulates distinct innate immune responses to different bacterial pathogens. Here, by using quantitative proteomics and functional assays, we discovered that NMUR-1 regulates F
1 FO ATP synthase and ATP production in response to pathogen infection, and that such regulation contributes to NMUR-1-mediated specificity of innate immunity. We further demonstrated that ATP biosynthesis and its contribution to defense is neurally controlled by the NMUR-1 ligand CAPA-1 and its expressing neurons ASG. These findings indicate that NMUR-1 neural signaling regulates the specificity of innate immunity by controlling energy homeostasis as part of defense against pathogens. Our study provides mechanistic insights into the emerging roles of NMU signaling in immunity across animal phyla., Competing Interests: DECLARATION OF INTERESTS The authors declare no competing interests.- Published
- 2024
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3. Coupling of acceptor-substituted diazo compounds and tertiary thioamides: synthesis of enamino carbonyl compounds and their pharmacological evaluation.
- Author
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Secka J, Pal A, Acquah FA, Mooers BHM, Karki AB, Mahjoub D, Fakhr MK, Wallace DR, Okada T, Toyooka N, Kuta A, Koduri N, Herndon D, Roberts KP, Wang Z, Hileman B, Rajagopal N, and Hussaini SR
- Abstract
This paper describes the synthesis of enamino carbonyl compounds by the copper(i)-catalyzed coupling of acceptor-substituted diazo compounds and tertiary thioamides. We plan to use this method to synthesize indolizidine (-)-237D analogs to find α6-selective antismoking agents. Therefore, we also performed in silico α6-nAchRs binding studies of selected products. Compounds with low root-mean-square deviation values showed more favorable binding free energies. We also report preliminary pharmacokinetic data on indolizidine (-)-237D and found it to have weak activity at CYP3A4. In addition, as enamino carbonyl compounds are also known for antimicrobial properties, we screened previously reported and new enamino carbonyl compounds for antibacterial, antimicrobial, and antifungal properties. Eleven compounds showed significant antimicrobial activities., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)
- Published
- 2022
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4. Children's ability to edit their memories when learning about the environment from credible and noncredible websites.
- Author
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Roberts KP, Wood KR, and Wylie BE
- Subjects
- Adolescent, Child, Humans, Internet, Memory
- Abstract
One of the many sources of information easily available to children is the internet and the millions of websites providing accurate, and sometimes inaccurate, information. In the current investigation, we examined children's ability to use credibility information about websites when learning about environmental sustainability. In two studies, children studied two different websites and were tested on what they had learned a week later using a multiple-choice test containing both website items and new distracters. Children were given either no information about the websites or were told that one of the websites (the noncredible website) contained errors and they should not use any information from that website to answer the test. In both studies, children aged 7- to 9-years reported information from the noncredible website even when instructed not to, whereas the 10- to 12-year-olds used the credibility warning to 'edit out' information that they had learned from the noncredible website. In Study 2, there was an indication that the older children spontaneously assessed the credibility of the website if credibility markers were made explicit. A plausible explanation is that, although children remembered information from the websites, they needed explicit instruction to bind the website content with the relevant source (the individual websites). The results have implications for children's learning in an open-access, digital age where information comes from many sources, credible and noncredible. Education in credibility evaluation may enable children to be critical consumers of information thereby resisting misinformation provided through public sources.
- Published
- 2021
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5. Enhanced hot electron lifetimes in quantum wells with inhibited phonon coupling.
- Author
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Esmaielpour H, Whiteside VR, Piyathilaka HP, Vijeyaragunathan S, Wang B, Adcock-Smith E, Roberts KP, Mishima TD, Santos MB, Bristow AD, and Sellers IR
- Abstract
Hot electrons established by the absorption of high-energy photons typically thermalize on a picosecond time scale in a semiconductor, dissipating energy via various phonon-mediated relaxation pathways. Here it is shown that a strong hot carrier distribution can be produced using a type-II quantum well structure. In such systems it is shown that the dominant hot carrier thermalization process is limited by the radiative recombination lifetime of electrons with reduced wavefunction overlap with holes. It is proposed that the subsequent reabsorption of acoustic and optical phonons is facilitated by a mismatch in phonon dispersions at the InAs-AlAsSb interface and serves to further stabilize hot electrons in this system. This lengthens the time scale for thermalization to nanoseconds and results in a hot electron distribution with a temperature of 490 K for a quantum well structure under steady-state illumination at room temperature.
- Published
- 2018
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6. Prosecutors' Perceptions on Questioning Children about Repeated Abuse.
- Author
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Powell MB, Burrows KS, Brubacher SP, and Roberts KP
- Abstract
The purpose of this study is to elicit guidance from prosecutors across Australia on questioning children about repeated events. Two focus groups were conducted. The first sought broad feedback concerning questioning children about repeated events. The second focused more specifically on eliciting feedback about techniques for aiding children in describing specific instances of repeated events. The techniques used are derived from a combination of empirical research and best practice interview guidelines. Data from both focus groups were compiled because themes were highly similar. Thematic analysis of the focus group discussions revealed three broad themes in prosecutors' perceptions about questioning children about repeated abuse: a) permitting children to provide a full generic account before describing individual episodes of abuse, b) using the information obtained during the generic account to create episode labels, and c) probing incidences of abuse chronologically. These themes are discussed within the context of the child development and mnemonic literature, and implications for interviewing protocols are drawn., Competing Interests: No potential conflict of interest was reported by the authors., (© 2017 The Australian and New Zealand Association of Psychiatry, Psychology and Law.)
- Published
- 2017
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7. Travel Burden and the Direct Medical Costs of Urologic Surgery.
- Author
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Olson DJ, Gore JL, Daratha KB, and Roberts KP
- Abstract
Background: Increased surgical volume is associated with better patient outcomes and shorter lengths of hospitalization. As a consequence, traveling to receive care from a high volume provider may be associated with better outcomes. However, travel may also be associated with a decision by the healthcare provider to increase the length of stay due to a decreased ability to return to the primary hospital should complications arise. Thus, research is needed to understand the relationship between the distance a patient must travel and their outcomes following urologic surgery. Objective: The purpose of this study was to determine whether the distance a patient travels to receive urologic surgery is associated with their length of hospital stay and direct medical hospitalization costs. Methods: This was a retrospective observational cohort study of 12 106 patients over 50 years of age undergoing transurethral resection of the prostate (TURP), radical prostatectomy (RP) or radical cystectomy (RC) in Washington State hospitals between 2009 and 2013. Distance traveled was determined by calculating the linear distance between zip code centroids of patient residence and the hospital performing their procedure. Patients were sorted into four groups classified by distance traveled (≤5 miles, 6-20 miles, 21-50 miles and ≥51 miles) and cost calculated using a charges-to-reimbursement ratio for each hospital. Statistical significance was determined using a Kruskal-Wallis test. Results: Patients traveling greater distances had significantly lower median medical costs compared with patients who lived closer to the hospitals where they underwent TURP and RP (TURP: ≤5 miles, $6243 and ≥51 miles, $5105, p≤0.001; RP: ≤5 miles, $12 407 and ≥51 miles, $11 882, p≤0.001), whereas there was no significant difference for patients undergoing RC (≤5 miles, $27 554 and ≥51 miles, $26 761, p=0.17). Likewise, patients traveling greater distances had significantly lower median lengths of hospitalization for TURP and RP (TURP: p≤0.001, RP: p≤0.001), while there was no difference for RC (p=0.50). Conclusions: Patient travel burden does appear to play a role in cost and length of hospital stay for select urologic procedures with variable levels of morbidity and recovery time. Although these findings are statistically significant, the magnitude of the effect is small.
- Published
- 2016
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8. The role of executive function in children's source monitoring with varying retrieval strategies.
- Author
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Earhart B and Roberts KP
- Abstract
Previous research on the relationship between executive function and source monitoring in young children has been inconclusive, with studies finding conflicting results about whether working memory and inhibitory control are related to source-monitoring ability. In this study, the role of working memory and inhibitory control in recognition memory and source monitoring with two different retrieval strategies were examined. Children (N = 263) aged 4-8 participated in science activities with two sources. They were later given a recognition and source-monitoring test, and completed measures of working memory and inhibitory control. During the source-monitoring test, half of the participants were asked about sources serially (one after the other) whereas the other half of the children were asked about sources in parallel (considering both sources simultaneously). Results demonstrated that working memory was a predictor of source-monitoring accuracy in both conditions, but inhibitory control was only related to source accuracy in the parallel condition. When age was controlled these relationships were no longer significant, suggesting that a more general cognitive development factor is a stronger predictor of source monitoring than executive function alone. Interestingly, the children aged 4-6 years made more accurate source decisions in the parallel condition than in the serial condition. The older children (aged 7-8) were overall more accurate than the younger children, and their accuracy did not differ as a function of interview condition. Suggestions are provided to guide further research in this area that will clarify the diverse results of previous studies examining whether executive function is a cognitive prerequisite for effective source monitoring.
- Published
- 2014
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9. A systematic analysis of a deep mouse epididymal sperm proteome.
- Author
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Chauvin T, Xie F, Liu T, Nicora CD, Yang F, Camp DG 2nd, Smith RD, and Roberts KP
- Subjects
- Animals, Chromatography, High Pressure Liquid, Cluster Analysis, Databases, Protein, Down-Regulation, Infertility, Male etiology, Infertility, Male metabolism, Male, Mice, Mutant Proteins metabolism, Peptide Fragments chemistry, Peptide Fragments metabolism, Proteome chemistry, Proteomics methods, Signal Transduction, Tandem Mass Spectrometry, Testis cytology, Transcriptome, Up-Regulation, Epididymis cytology, Proteome metabolism, Spermatozoa metabolism
- Abstract
Spermatozoa are highly specialized cells that, when mature, are capable of navigating the female reproductive tract and fertilizing an oocyte. The sperm cell is thought to be largely quiescent in terms of transcriptional and translational activity. As a result, once it has left the male reproductive tract, the sperm cell is essentially operating with a static population of proteins. It therefore is theoretically possible to understand the protein networks contained in a sperm cell and to deduce its cellular function capabilities. To this end, we performed a proteomic analysis of mouse sperm isolated from the cauda epididymis and confidently identified 2850 proteins, which to our knowledge is the most comprehensive sperm proteome for any species reported to date. These proteins comprise many complete cellular pathways, including those for energy production via glycolysis, beta-oxidation and oxidative phosphorylation, protein folding and transport, and cell signaling systems. This proteome should prove a useful tool for assembly and testing of protein networks important for sperm function.
- Published
- 2012
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10. Capillary electrophoretic separation of nanoparticles.
- Author
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Oszwałdowski S, Zawistowska-Gibuła K, and Roberts KP
- Subjects
- Adsorption, DNA chemistry, Biological Assay instrumentation, Electrophoresis, Capillary methods, Nanoparticles chemistry
- Abstract
In the present work, CdSe nanocrystals (NCs) synthesized with a trioctylphosphine surface passivation layer were modified using amphiphilic molecules to form a surface bilayer capable of providing stable NCs aqueous solutions. Such modified nanocrystals were used as a test solute in order to analyze new electrophoretic phenomena, by applying a micellar plug as a separation tool for discriminating nanocrystals between micellar and micelle-free zones during electrophoresis. The distribution of NCs between both zones depended on the affinity of nanocrystals towards the micellar zone, and this relies on the kind of surface ligands attached to the NCs, as well as electrophoretic conditions applied. In this case, the NCs that migrated within a micellar zone can be focused using a preconcentration mechanism. By modifying electrophoretic conditions, NCs were forced to migrate outside the micellar zone in the form of a typical CZE peak. In this situation, a two-order difference in separation efficiencies, in terms of theoretical plates, was observed between focused NCs (N ~ 10(7)) and a typical CZE peak for NCs (N ~ 10(5)). By applying the amino-functionalized NCs the preconcentration of NCs, using a micellar plug, was examined, with the conclusion that preconcentration efficiency, in terms of the enhancement factor for peak height (SEF(height)) can be, at least 20. The distribution effect was applied to separate CdSe/ZnS NCs encapsulated in silica, as well as surface-modified with DNA, which allows the estimation of the yield of conjugation of biologically active molecules to a particle surface.
- Published
- 2011
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11. Cellular biophysics during freezing of rat and mouse sperm predicts post-thaw motility.
- Author
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Hagiwara M, Choi JH, Devireddy RV, Roberts KP, Wolkers WF, Makhlouf A, and Bischof JC
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- Animals, Calorimetry, Differential Scanning, Cell Membrane Permeability, Freezing, Male, Mice, Models, Biological, Rats, Cryopreservation, Semen Preservation, Sperm Motility, Spermatozoa metabolism, Water metabolism
- Abstract
Though cryopreservation of mouse sperm yields good survival and motility after thawing, cryopreservation of rat sperm remains a challenge. This study was designed to evaluate the biophysics (membrane permeability) of rat in comparison to mouse to better understand the cooling rate response that contributes to cryopreservation success or failure in these two sperm types. In order to extract subzero membrane hydraulic permeability in the presence of ice, a differential scanning calorimeter (DSC) method was used. By analyzing rat and mouse sperm frozen at 5 degrees C/min and 20 degrees C/min, heat release signatures characteristic of each sperm type were obtained and correlated to cellular dehydration. The dehydration response was then fit to a model of cellular water transport (dehydration) by adjusting cell-specific biophysical (membrane hydraulic permeability) parameters L(pg) and E(Lp). A "combined fit" (to 5 degrees C/min and 20 degrees C/min data) for rat sperm in Biggers-Whitten-Whittingham media yielded L(pg) = 0.007 microm min(-1) atm(-1) and E(Lp) = 17.8 kcal/mol, and in egg yolk cryopreservation media yielded L(pg) = 0.005 microm min(-1) atm(-1) and E(Lp) = 14.3 kcal/mol. These parameters, especially the activation energy, were found to be lower than previously published parameters for mouse sperm. In addition, the biophysical responses in mouse and rat sperm were shown to depend on the constituents of the cryopreservation media, in particular egg yolk and glycerol. Using these parameters, optimal cooling rates for cryopreservation were predicted for each sperm based on a criteria of 5%-15% normalized cell water at -30 degrees C during freezing in cryopreservation media. These predicted rates range from 53 degrees C/min to 70 degrees C/min and from 28 degrees C/min to 36 degrees C/min in rat and mouse, respectively. These predictions were validated by comparison to experimentally determined cryopreservation outcomes, in this case based on motility. Maximum motility was obtained with freezing rates between 50 degrees C/min and 80 degrees C/min for rat and at 20 degrees C/min with a sharp drop at 50 degrees C/min for mouse. In summary, DSC experiments on mouse and rat sperm yielded a difference in membrane permeability parameters in the two sperm types that, when implemented in a biophysical model of water transport, reasonably predict different optimal cooling rate outcomes for each sperm after cryopreservation.
- Published
- 2009
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12. Molecular cloning and expression of the CRISP family of proteins in the boar.
- Author
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Vadnais ML, Foster DN, and Roberts KP
- Subjects
- Acrosome Reaction physiology, Amino Acid Sequence, Animals, Cloning, Molecular, Computational Biology, Culture Media, DNA, Complementary biosynthesis, DNA, Complementary genetics, Epididymis cytology, Epididymis metabolism, Male, Membrane Glycoproteins biosynthesis, Molecular Sequence Data, RNA biosynthesis, RNA isolation & purification, Recombinant Proteins biosynthesis, Recombinant Proteins genetics, Reverse Transcriptase Polymerase Chain Reaction, Semen physiology, Sperm Capacitation physiology, Spermatozoa metabolism, Swine, Testis metabolism, Gene Expression Regulation physiology, Membrane Glycoproteins genetics
- Abstract
The family of mammalian cysteine-rich secretory proteins (CRISP) have been well characterized in the rat, mouse, and human. Here we report the molecular cloning and expression analysis of CRISP1, CRISP2, and CRISP3 in the boar. A partial sequence published in the National Center for Biotechnology Information (NCBI) database was used to derive the full-length sequences for CRISP1 and CRISP2 using rapid amplification of cDNA ends. RT-PCR confirmed the expression of these mRNAs in the boar reproductive tract, and real time RT-PCR showed CRISP1 to be highly expressed throughout the epididymis, with CRISP2 highly expressed in the testis. A search of the porcine genomic sequence in the NCBI database identified a BAC (CH242-199E6) encoding the CRISP1 gene. This BAC is derived from porcine Chromosome 7 and is syntenic with the regions of the mouse, rat, and human genomes encoding the CRISP gene family. This BAC was found to encode a third CRISP protein with a predicted amino acid sequence of high similarity to human CRISP3. Using RT-PCR we show that CRISP3 expression in the boar reproductive tract is confined to the prostate. Recombinant porcine (rp) CRISP2 protein was produced and purified. When incubated with capacitated boar sperm, rpCRISP2 induced an acrosome reaction, consistent with its demonstrated ability to alter the activity of calcium channels.
- Published
- 2008
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13. Association of the protein D and protein E forms of rat CRISP1 with epididymal sperm.
- Author
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Roberts KP, Ensrud-Bowlin KM, Piehl LB, Parent KR, Bernhardt ML, and Hamilton DW
- Subjects
- Acrosome metabolism, Acrosome ultrastructure, Animals, Blotting, Western, Coculture Techniques, Detergents pharmacology, Epididymal Secretory Proteins, Epididymis cytology, Glucosides pharmacology, Immunohistochemistry, Indicators and Reagents, Male, Membrane Glycoproteins biosynthesis, Protein Binding, Rats, Rats, Sprague-Dawley, Temperature, Epididymis physiology, Membrane Glycoproteins genetics, Membrane Glycoproteins physiology, Spermatozoa physiology
- Abstract
Cysteine-rich secretory protein 1 (CRISP1) is a secretory glycoprotein produced by the rat epididymal epithelium in two forms, referred to as proteins D and E. CRISP1 has been implicated in sperm-egg fusion and has been shown to suppress capacitation in rat sperm. Several studies have suggested that CRISP1 associates transiently with the sperm surface, whereas others have shown that at least a portion of CRISP1 persists on the surface. In the present study, we demonstrate that protein D associates transiently with the sperm surface in a concentration-dependent manner, exhibiting saturable binding to both caput and cauda sperm in a concentration range that is consistent with its capacitation-inhibiting activity. In contrast, protein E persists on the sperm surface after all exogenous protein D has been dissociated. Comparison of caput and cauda sperm reveal that protein E becomes bound to the sperm in the cauda epididymidis. We show that protein E associates with caput sperm, which do not normally have it on their surfaces, in vitro in a time- and temperature-dependent manner. These studies demonstrate that most CRISP1 interacts with sperm transiently, possibly with a specific receptor on the sperm surface, consistent with its action in suppressing capacitation during epididymal storage of sperm. These studies also confirm a tightly bound population of protein E that could act in the female tract.
- Published
- 2008
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14. Structure and function of epididymal protein cysteine-rich secretory protein-1.
- Author
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Roberts KP, Johnston DS, Nolan MA, Wooters JL, Waxmonsky NC, Piehl LB, Ensrud-Bowlin KM, and Hamilton DW
- Subjects
- Amino Acid Sequence, Animals, Conserved Sequence, Humans, Male, Mammals, Membrane Glycoproteins metabolism, Molecular Sequence Data, Rats, Membrane Glycoproteins genetics, Spermatozoa physiology
- Abstract
Cysteine-rich secretory protein-1 (CRISP-1) is a glycoprotein secreted by the epididymal epithelium. It is a member of a large family of proteins characterized by two conserved domains and a set of 16 conserved cysteine residues. In mammals, CRISP-1 inhibits sperm-egg fusion and can suppress sperm capacitation. The molecular mechanism of action of the mammalian CRISP proteins remains unknown, but certain non-mammalian CRISP proteins can block ion channels. In the rat, CRISP-1 comprises two forms referred to as Proteins D and E. Recent work in our laboratory demonstrates that the D form of CRISP-1 associates transiently with the sperm surface, whereas the E form binds tightly. When the spermatozoa are washed, the E form of CRISP-1 persists on the sperm surface after all D form has dissociated. Cross-linking studies demonstrate different protein-protein interaction patterns for D and E, although no binding partners for either protein have yet been identified. Mass spectrometric analyses revealed a potential post-translational modification on the E form that is not present on the D form. This is the only discernable difference between Proteins D and E, and presumably is responsible for the difference in behavior of these two forms of rat CRISP-1. These studies demonstrate that the more abundant D form interacts with spermatozoa transiently, possibly with a specific receptor on the sperm surface, consistent with a capacitation-suppressing function during sperm transit and storage in the epididymis, and also confirm a tightly bound population of the E form that could act in the female reproductive tract.
- Published
- 2007
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15. The roles of prior experience and the timing of misinformation presentation on young children's event memories.
- Author
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Roberts KP and Powell MB
- Subjects
- Child, Child, Preschool, Conflict, Psychological, Female, Humans, Interview, Psychological, Male, Reality Testing, Time Factors, Attention, Concept Formation, Culture, Mental Recall, Retention, Psychology, Suggestion
- Abstract
The current study addressed how the timing of interviews affected children's memories of unique and repeated events. Five- to six-year-olds (N=125) participated in activities 1 or 4 times and were misinformed either 3 or 21 days after the only or last event. Although single-experience children were subsequently less accurate in the 21- versus 3-day condition, the timing of the misinformation session did not affect memories of repeated-experience children regarding invariant details. Children were more suggestible in the 21- versus 3-day condition for variable details when the test occurred soon after misinformation presentation. Thus, timing differentially affected memories of single and repeated events and depended on the combination of event-misinformation and misinformation-test delays rather than the overall retention interval.
- Published
- 2007
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16. Effects of seminal plasma on cooling-induced capacitative changes in boar sperm.
- Author
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Vadnais ML and Roberts KP
- Subjects
- Acrosome Reaction physiology, Animals, Male, Signal Transduction physiology, Swine, Cold Temperature, Phosphotyrosine metabolism, Semen physiology, Sperm Capacitation physiology, Spermatozoa metabolism
- Abstract
Porcine seminal plasma (SP) has been shown to contain factors that have a decapacitative or capacitation-inhibiting effect on sperm. The objectives of the present study were to compare the capacitative changes observed in cooled sperm with those seen in sperm after in vitro capacitation and to determine whether SP could prevent these changes. Sperm were subjected to incubation or to slow cooling under noncapacitating or capacitating conditions. The effect of SP on protein tyrosine phosphorylation and the ability of the sperm to undergo an acrosome reaction (AR) were determined. Cooled sperm displayed an increased level of tyrosine phosphorylation and a higher percentage of induced AR sperm compared to incubated sperm. The addition of SP inhibited the number of ARs that occurred during incubation and cooling. These results suggest that cooling of sperm augments the capacitative changes in sperm, and that SP contains a factor(s) that effectively prevents these changes.
- Published
- 2007
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17. Acute effect of vasectomy on the function of the rat epididymal epithelium and vas deferens.
- Author
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Lavers AE, Swanlund DJ, Hunter BA, Tran ML, Pryor JL, and Roberts KP
- Subjects
- Animals, Blotting, Northern, Clusterin biosynthesis, Epithelium physiology, Immunohistochemistry, Male, Membrane Glycoproteins biosynthesis, Osteopontin biosynthesis, RNA, Messenger metabolism, Rats, Rats, Sprague-Dawley, Transferrin biosynthesis, Epididymis physiology, Vas Deferens physiology, Vasectomy
- Abstract
Persistent infertility after apparently successful vasectomy reversal is common. One possible etiology is epididymal epithelial dysfunction resulting in improper sperm maturation after vasectomy reversal. The epididymal epithelium secretes a number of proteins that are thought to be required for the maturation of sperm. Ligation of the vas deferens during vasectomy may affect the synthesis of some of these proteins. In the present study, the function of the epididymal epithelium was assessed at early times after vasectomy (1, 4, and 7 days) by measuring the level of mRNA of 4 secreted proteins: Crisp-1, clusterin, osteopontin, and transferrin. In addition, the site of synthesis of these proteins was determined by immunocytochemistry. The results demonstrated that the expression of Crisp-1 and clusterin, representative epididymal secretory proteins, was largely unaffected by vasectomy. However, osteopontin mRNA increased in the vas deferens in response to vasectomy. Immunocytochemical localization of osteopontin suggested that both infiltrating immune cells and deferential luminal epithelium were responsible for this up-regulation. Transferrin expression was viewed as a marker for immune cells at the site of injury. However, both the caput epididymis and deferential epithelia were found to express transferrin, in addition to immune cells. In conclusion, there appear to be only minor changes in expression of genes encoding epididymal secretory proteins acutely after vasectomy, but, not surprisingly, there was evidence of an inflammatory response after vasectomy.
- Published
- 2006
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18. Identification of rat cysteine-rich secretory protein 4 (Crisp4) as the ortholog to human CRISP1 and mouse Crisp4.
- Author
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Nolan MA, Wu L, Bang HJ, Jelinsky SA, Roberts KP, Turner TT, Kopf GS, and Johnston DS
- Subjects
- Animals, DNA, Complementary, Humans, Male, Mice, Proteins metabolism, Proteins physiology, Rats, Seminal Plasma Proteins metabolism, Sequence Homology, Amino Acid, Spermatozoa physiology, Synteny, Epididymis metabolism, Membrane Glycoproteins genetics, Proteins genetics, Seminal Plasma Proteins genetics
- Abstract
Cysteine-rich secretory proteins (CRISPs) are present in a diverse population of organisms and are defined by 16 conserved cysteine residues spanning a plant pathogenesis related-1 and a C-terminal cysteine-rich domain. To date, the diversification of mammalian CRISPs is evidenced by the existence of two, three, and four paralogous genes in the rat, human, and mouse, respectively. The current study identifies a third rat Crisp paralog we term Crisp4. The gene for Crisp4 is on rat chromosome 9 within 1 Mb of both the Crisp1 and Crisp2 genes. The full-length transcript for this gene was cloned from rat epididymal RNA and encodes a protein that shares 69% and 91% similarity with human CRISP1 and mouse CRISP4, respectively. Expression of rat Crisp4 is most abundant in the epididymis, with the highest levels of transcription observed in the caput and corpus epididymis. In contrast, rat CRISP4 protein is most abundant in the corpus and cauda regions of the epididymis. Rat CRISP4 protein is also present in caudal sperm extracts, appearing as a detergent-soluble form at the predicted MWR (26 kDa). Our data identify rat Crisp4 as the true ortholog to human CRISP1 and mouse Crisp4, and demonstrate its interaction with spermatozoa in the epididymis.
- Published
- 2006
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19. Inhibition of capacitation-associated tyrosine phosphorylation signaling in rat sperm by epididymal protein Crisp-1.
- Author
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Roberts KP, Wamstad JA, Ensrud KM, and Hamilton DW
- Subjects
- Acrosome Reaction physiology, Animals, Bicarbonates metabolism, Blotting, Western, Calcium physiology, Cholesterol metabolism, Cholesterol physiology, Culture Media, Cyclic AMP physiology, Dose-Response Relationship, Drug, Electrophoresis, Polyacrylamide Gel, Epididymis drug effects, Immunohistochemistry, In Vitro Techniques, Kinetics, Male, Phosphorylation, Rats, Rats, Sprague-Dawley, Signal Transduction drug effects, Sperm Capacitation drug effects, Spermatozoa drug effects, Sphingolipids metabolism, Epididymis physiology, Membrane Glycoproteins pharmacology, Signal Transduction physiology, Sperm Capacitation physiology, Spermatozoa physiology, Tyrosine physiology
- Abstract
Ejaculated sperm are unable to fertilize an egg until they undergo capacitation. Capacitation results in the acquisition of hyperactivated motility, changes in the properties of the plasma membrane, including changes in proteins and glycoproteins, and acquisition of the ability to undergo the acrosome reaction. In all mammalian species examined, capacitation requires removal of cholesterol from the plasma membrane and the presence of extracellular Ca2+ and HCO3-. We designed experiments to elucidate the conditions required for in vitro capacitation of rat spermatozoa and the effects of Crisp-1, an epididymal secretory protein, on capacitation. Protein tyrosine phosphorylation, a hallmark of capacitation in sperm of other species, occurs during 5 h of in vitro incubation, and this phosphorylation is dependent upon HCO3-, Ca2+, and the removal of cholesterol from the membrane. Crisp-1, which is added to the sperm surface in the epididymis in vivo, is lost during capacitation, and addition of exogenous Crisp-1 to the incubation medium inhibits tyrosine phosphorylation in a dose-dependent manner, thus inhibiting capacitation and ultimately the acrosome reaction. Inhibition of capacitation by Crisp-1 occurs upstream of the production of cAMP by the sperm.
- Published
- 2003
- Full Text
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20. McLachlan et al (2002) point out the fact that mammalian spermatogenesis requires an intratesticular testosterone concentration many times higher than normal serum levels.
- Author
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Roberts KP
- Subjects
- Animals, Male, Osmolar Concentration, Rats, Spermatogenesis physiology, Testis metabolism, Testosterone metabolism
- Published
- 2002
21. A comparative analysis of expression and processing of the rat epididymal fluid and sperm-bound forms of proteins D and E.
- Author
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Roberts KP, Ensrud KM, and Hamilton DW
- Subjects
- Animals, Antibodies, Monoclonal, Blotting, Western, Body Fluids metabolism, Enzyme-Linked Immunosorbent Assay, Epitopes genetics, Gene Expression Regulation genetics, Immunohistochemistry, Male, Membranes metabolism, Microscopy, Confocal, Peptide Library, Rats, Rats, Sprague-Dawley, Epididymis metabolism, Glycoproteins biosynthesis, Glycoproteins genetics, Membrane Glycoproteins biosynthesis, Membrane Glycoproteins genetics, Seminal Plasma Proteins biosynthesis, Seminal Plasma Proteins genetics, Spermatozoa metabolism
- Abstract
The mammalian epididymis secretes numerous proteins important for sperm maturation. Among these are proteins D and E, which belong to the CRISP family (cysteine-rich secretory proteins) and are the product of the Crisp-1 gene. These proteins have been the focus of a number of studies and have been implicated in sperm/egg fusion. Protein D and protein E have been purified to apparent homogeneity in several laboratories. Polyclonal antibodies raised against each protein typically cross-reacted with both proteins, suggesting that they were immunologically similar, if not identical. Our laboratory has previously reported the generation of a monoclonal antibody (mAb 4E9) that recognizes only protein E. Using mAb 4E9, the localization of protein E was shown to be domain specific on the sperm surface and there is processing of the protein in the fluid, with only the lowest molecular weight form associating with sperm. Subsequent purification and amino acid sequencing of protein D confirmed that proteins D and E are nearly identical and differ only by presence of the 4E9 epitope on protein E. Here we report the generation of antibodies to regions of amino acid sequence identity in proteins D and E. Using these antibodies, we demonstrate that protein D associates with the sperm head and that a portion of this protein may be proteolytically processed. In addition, we demonstrate that the proteolytic processing of protein E occurs in the carboxy terminal region of this protein. The data also suggest that a portion of protein D may also undergo processing, similar to that of protein E. Finally, we use these antibodies to demonstrate that proteins D and E are differentially expressed by the epididymal epithelium. Taken together, these data suggest that proteins D and E may have individual roles in sperm function.
- Published
- 2002
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22. Cryopreservation of equine sperm: optimal cooling rates in the presence and absence of cryoprotective agents determined using differential scanning calorimetry.
- Author
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Devireddy RV, Swanlund DJ, Olin T, Vincente W, Troedsson MH, Bischof JC, and Roberts KP
- Subjects
- Algorithms, Animals, Calorimetry, Differential Scanning, Cell Membrane physiology, Cell Membrane ultrastructure, Cell Survival physiology, Computer Simulation, Cryopreservation, Freezing, In Vitro Techniques, Male, Temperature, Water metabolism, Cryoprotective Agents pharmacology, Horses physiology, Semen Preservation, Spermatozoa drug effects, Spermatozoa physiology
- Abstract
Optimization of equine sperm cryopreservation protocols requires an understanding of the water permeability characteristics and volumetric shrinkage response during freezing. A cell-shape-independent differential scanning calorimeter (DSC) technique was used to measure the volumetric shrinkage during freezing of equine sperm suspensions at cooling rates of 5 degrees C/min and 20 degrees C/min in the presence and absence of cryoprotective agents (CPAs), i.e., in the Kenney extender and in the lactose-EDTA extender, respectively. The equine sperm was modeled as a cylinder of length 36.5 microm and a radius of 0.66 microm with an osmotically inactive cell volume (V(b)) of 0.6V(o), where V(o) is the isotonic cell volume. Sperm samples were collected using water-insoluble Vaseline in the artificial vagina and slow cooled at < or = 0.3 degrees C/min in an Equitainer-I from 37 degrees C to 4 degrees C. By fitting a model of water transport to the experimentally obtained DSC volumetric shrinkage data, the best-fit membrane permeability parameters (L(pg) and E(Lp)) were determined. The combined best-fit parameters of water transport (at both 5 degrees C/min and 20 degrees C/min) in Kenney extender (absence of CPAs) are L(pg) = 0.02 microm min(-1) atm(-1) and E(Lp) = 32.7 kcal/mol with a goodness-of-fit parameter R(2) = 0.96, and the best-fit parameters in the lactose-EDTA extender (the CPA medium) are L(pg)[cpa] = 0.008 microm min(-1) atm(-1) and E(Lp)[cpa] = 12.1 kcal/mol with R(2) = 0.97. These parameters suggest that the optimal cooling rate for equine sperm is approximately 29 degrees C/min and is approximately 60 degrees C/min in the Kenney extender and in the lactose-EDTA extender. These rates are predicted assuming no intracellular ice formation occurs and that the approximately 5% of initial osmotically active water volume trapped inside the cells at -30 degrees C will form innocuous ice on further cooling. Numerical simulations also showed that in the lactose-EDTA extender, equine sperm trap approximately 3.4% and approximately 7.1% of the intracellular water when cooled at 20 degrees C/min and 100 degrees C/min, respectively. As an independent test of this prediction, the percentage of viable equine sperm was obtained after freezing at 6 different cooling rates (2 degrees C/min, 20 degrees C/min, 50 degrees C/min, 70 degrees C/min, 130 degrees C/min, and 200 degrees C/min) to -80 degrees C in the CPA medium. Sperm viability was essentially constant between 20 degrees C/min and 130 degrees C/min.
- Published
- 2002
- Full Text
- View/download PDF
23. Expression of crisp-1 mRNA splice variants in the rat epididymis, and comparative analysis of the rat and mouse crisp-1 gene regulatory regions.
- Author
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Roberts KP, Hoffman LB, Ensrud KM, and Hamilton DW
- Subjects
- Animals, Base Sequence, Cloning, Molecular, Epididymal Secretory Proteins, Exons, Gene Expression Regulation genetics, Introns, Male, Mice, Mice, Inbred Strains, Molecular Sequence Data, RNA, Messenger analysis, Rats, Rats, Sprague-Dawley, Regulatory Sequences, Nucleic Acid genetics, Reverse Transcriptase Polymerase Chain Reaction, Species Specificity, Transcription, Genetic genetics, Alternative Splicing genetics, Epididymis physiology, Metalloproteins genetics, Testicular Hormones genetics
- Abstract
The rat Crisp-1 gene encodes Protein DE (acidic epididymal glycoprotein; AEG), a glycoprotein secreted by the epididymal epithelium that associates with maturing sperm and has been implicated in the process of sperm-egg fusion. Previous characterization of the Crisp-1 messenger RNA in the rat epididymis has demonstrated the presence of 3 splice variants (Klemme et at, 1999). This study was undertaken to determine if expression of the Crisp-1 splice variants in the rat epididymis is region-specific and correlates with the region-specific pattern of synthesis of the D and E forms of the Crisp-1 protein. Expression of each of the splice variants was shown by RNase protection assays to be under the control of androgens, but they are not differentially regulated either within the epididymal segments or along the length of the organ. The reported structure of the mouse Crisp-1 gene does not include an exon that is equivalent to the rat exon 1, suggesting that the rat splice variants cannot exist in the mouse and may be specific to the rat. Furthermore, the mouse transcription start site is situated in a different region of the gene than in the rat. In this study, a comparison of the mouse and rat genes in the region flanking the mouse exon 1 and the rat exon 2 (within the rat intron 1) shows greater than 80% sequence identity, including the conservation of several putative androgen receptor binding sites. In addition, the rat gene is shown to have a corrupted TATA box in intron 1 that corresponds to the TATA box located in the mouse gene. These observations explain the preferential transcription for the mouse gene in this region, while the predominant start site for the rat gene is 5' of the upstream exon 1. Although an exon corresponding to the rat exon 1 has not been found in the mouse gene, reverse transcription-polymerase chain reaction experiments using mouse epididymal RNA suggest that such an exon exists in the mouse gene and is transcribed at low frequency.
- Published
- 2001
24. The effect of extracellular ice and cryoprotective agents on the water permeability parameters of human sperm plasma membrane during freezing.
- Author
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Devireddy RV, Swanlund DJ, Roberts KP, Pryor JL, and Bischof JC
- Subjects
- Calorimetry, Differential Scanning methods, Cell Membrane drug effects, Computer Simulation, Cryopreservation methods, Culture Media, Glycerol pharmacology, Humans, Ice, Male, Spermatozoa drug effects, Water, Cell Membrane Permeability drug effects, Freezing, Spermatozoa physiology
- Abstract
A firm biophysical basis for the cryopreservation of human spermatozoa is limited by a lack of knowledge regarding the water permeability characteristics during freezing in the presence of extracellular ice and cryoprotective agents (CPA). Cryomicroscopy cannot be used to measure dehydration during freezing in human spermatozoa because of their highly non-spherical shape and their small dimensions which are at the limits of light microscopic resolution. Using a new shape-independent differential scanning calorimeter (DSC) technique, volumetric shrinkage during freezing of human sperm cell suspensions was obtained at cooling rates of 5 and 10 degrees C/min in the presence of extracellular ice and CPA. Using previously published data, the human sperm cell was modelled as a cylinder of length 40.2 micrometer and a radius of 0.42 micrometer with an osmotically inactive cell volume, V(b), of 0.23V(o), where V(o) is the isotonic cell volume. By fitting a model of water transport to the experimentally obtained volumetric shrinkage data, the best fit membrane permeability parameters (L(pg) and E(Lp)) were determined. The 'combined best fit' membrane permeability parameters at 5 and 10 degrees C/min for human sperm cells in modified media are: L(pg) = 2. 4x10(-14) m(3)/Ns (0.14 micrometer/min-atm) and E(Lp) = 357.7 kJ/mol (85. 5 kcal/mol) (R(2) = 0.98), and in CPA media (with 6% glycerol and 10% egg yolk) are L(pg)[cpa] = 0.67x10(-14) m(3)/Ns (0.04 micrometer/min-atm) and E(Lp)[cpa] = 138.9 kJ/mol (33.2 kcal/mol) (R(2) = 0.98). These parameters are significantly different from previously published parameters for human spermatozoa obtained at suprazero temperatures and at subzero temperatures in the absence of extracellular ice. The parameters obtained in this study also suggest that damaging intracellular ice formation (IIF) could occur in human sperm cells at cooling rates as low as 25-45 degrees C/min, depending on the concentrations of the CPA. This may help to explain the discrepancy between the empirically determined optimal cryopreservation cooling rates (<100 degrees C/min) and the numerically predicted optimal cooling rates (>7000 degrees C/min) obtained using previously published suprazero human sperm permeability parameters which do not account for the presence of extracellular ice.
- Published
- 2000
- Full Text
- View/download PDF
25. Cloning and characterization of the rat Crisp-1 gene.
- Author
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Klemme LM, Roberts KP, Hoffman LB, Ensrud KM, Siiteri JE, and Hamilton DW
- Subjects
- Alternative Splicing, Amino Acid Sequence, Animals, Base Sequence, Binding Sites, Cloning, Molecular, DNA chemistry, DNA genetics, Epididymal Secretory Proteins, Exons, Gene Dosage, Genes genetics, Introns, Male, Molecular Sequence Data, Promoter Regions, Genetic, Rats, Rats, Sprague-Dawley, Sequence Alignment, Sequence Analysis, DNA, Sequence Homology, Amino Acid, Sequence Homology, Nucleic Acid, Transcription Factors metabolism, Transcription, Genetic, Metalloproteins genetics, Testicular Hormones genetics
- Abstract
Rat androgen-regulated acidic epididymal glycoprotein (AEG), also known as Protein DE, is a product of the Crisp-1 gene. Protein DE is secreted into the epididymal lumen and binds to sperm heads during their transit through the epididymis. In experiments reported here, the rat Crisp-1 gene has been cloned and its structure determined. The rat Crisp-1 gene spans 38kb and contains nine exons encoding an 1120bp epididymal Protein DE mRNA. The boundaries of the protein-coding exons are structurally organized similar to the mouse Crisp-1 gene, except for the 5' untranslated sequence, which is encoded by one exon in the mouse Crisp-1 gene and two exons in the rat gene. All the introns are flanked by AG/GT consensus splice sequences. Crisp-1 is a single-copy gene as shown by the presence of single bands by Southern blot analysis and PCR using rat genomic DNA as template. Recognition sites for steroid hormone receptors are present in the 5' flanking region and in intron 1, consistent with the known regulation of Protein DE expression by androgens. RT-PCR experiments demonstrate three splice variant mRNAs involving the non-coding exon 2. The Crisp-1 gene also produces an mRNA without an exon 1 sequence by utilizing a transcription start site in intron 1, 5' of the start of exon 2. All forms of the Crisp-1 mRNA are predicted to encode Protein DE.
- Published
- 1999
- Full Text
- View/download PDF
26. Subzero water permeability parameters of mouse spermatozoa in the presence of extracellular ice and cryoprotective agents.
- Author
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Devireddy RV, Swanlund DJ, Roberts KP, and Bischof JC
- Subjects
- Animals, Calorimetry, Differential Scanning, Cell Separation, Cell Survival, Freezing, Male, Mice, Mice, Inbred ICR, Semen Preservation, Sperm Motility, Thermodynamics, Cell Membrane Permeability, Cryopreservation, Cryoprotective Agents pharmacology, Ice, Spermatozoa metabolism, Water metabolism
- Abstract
Optimization of techniques for cryopreservation of mammalian sperm is limited by a lack of knowledge regarding water permeability characteristics during freezing in the presence of extracellular ice and cryoprotective agents (CPAs). Cryomicroscopy cannot be used to measure dehydration during freezing in mammalian sperm because they are highly nonspherical and their small dimensions are at the limits of light microscopic resolution. Using a new shape-independent differential scanning calorimeter (DSC) technique, volumetric shrinkage during freezing of ICR mouse epididymal sperm cell suspensions was obtained at cooling rates of 5 and 20 degrees C/min in the presence of extracellular ice and CPAs. Using previously published data, the mouse sperm cell was modeled as a cylinder (122-microm long, radius 0.46 microm) with an osmotically inactive cell volume (V(b)) of 0.61V(o), where V(o) is the isotonic cell volume. By fitting a model of water transport to the experimentally obtained volumetric shrinkage data, the best-fit membrane permeability parameters (L(pg) and E(Lp)) were determined. The "combined best-fit" membrane permeability parameters at 5 and 20 degrees C/min for mouse sperm cells in solution are as follows: in D-PBS: L(pg) = 1.7 x 10(-15) m(3)/Ns (0.01 microm/min-atm) and E(Lp) = 94.1 kJ/mole (22.5 kcal/mole) (R(2) = 0.94); in "low" CPA media (consisting of 1% glycerol, 6% raffinose, and 15% egg yolk in D-PBS): L(pg)[cpa] = 1.7 x 10(-15) m(3)/Ns (0.01 microm/min-atm) and E(Lp)[cpa] = 122.2 kJ/mole (29.2 kcal/mole) (R(2) = 0.98); and in "high" CPA media (consisting of 4% glycerol, 16% raffinose, and 15% egg yolk in D-PBS): L(pg)[cpa] = 0.68 x 10(-15) m(3)/Ns (0.004 microm/min-atm) and E(Lp)[cpa] = 63.6 kJ/mole (15.2 kcal/mole) (R(2) = 0.99). These parameters are significantly different than previously published parameters for mammalian sperm obtained at suprazero temperatures and at subzero temperatures in the absence of extracellular ice. The parameters obtained in this study also suggest that damaging intracellular ice formation (IIF) could occur in mouse sperm cells at cooling rates as low as 25-45 degrees C/min, depending on the concentrations of the CPAs. This may help to explain the discrepancy between the empirically determined optimal cryopreservation cooling rates, 10-40 degrees C/min, and the numerically predicted optimal cooling rates, greater than 5000 degrees C/min, obtained using suprazero mouse sperm permeability parameters that do not account for the presence of extracellular ice. As an independent test of this prediction, the percentages of viable and motile sperm cells were obtained after freezing at two different cooling rates ("slow" or 5 degrees C/min; "fast," or 20 degrees C/min) in both the low and high CPA media. The greatest sperm motility and viability was found with the low CPA media under fast (20 degrees C/min) cooling conditions.
- Published
- 1999
- Full Text
- View/download PDF
27. Principles of sequence-tagged site selection in screening for Y deletions.
- Author
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Pryor JL and Roberts KP
- Subjects
- Expressed Sequence Tags, Humans, Male, Gene Deletion, Infertility, Male genetics, Y Chromosome
- Published
- 1998
- Full Text
- View/download PDF
28. Regional distribution of 5alpha-reductase type 1 and type 2 mRNA along the human epididymis.
- Author
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Mahony MC, Swanlund DJ, Billeter M, Roberts KP, and Pryor JL
- Subjects
- Adult, Blotting, Northern, Cholestenone 5 alpha-Reductase, Epididymis enzymology, Humans, Male, Peptidylprolyl Isomerase genetics, Polymerase Chain Reaction, Prospective Studies, Testis enzymology, Tissue Distribution, Transcription, Genetic, Isoenzymes genetics, Oxidoreductases genetics, RNA, Messenger metabolism
- Abstract
Objective: To determine the regional distribution and relative expression of 5alpha-reductase type 1 and type 2 mRNA within the human testis and regions of the epididymis., Design: Prospective observational study., Setting: University academic medical center., Patient(s): Two young adult male organ donors., Intervention(s): None, Main Outcome Measure(s): The distribution of 5alpha-reductase type 1 and type 2 mRNA in the testis and regions of the epididymis was detected by Northern blot analysis. The relative abundance of each 5alpha-reductase mRNA was evaluated using semiquantitative reverse transcriptase-polymerase chain reaction (RT-PCR) in which cyclophilin mRNA, a house-keeping gene product, was coamplified as the reference standard., Result(s): Northern blot analysis revealed the 5alpha-reductase type 2 transcript in the midcaput, distal caput, corpus, and proximal cauda of the epididymis, but the transcript was undetectable in the testis, proximal caput, and distal cauda region. No transcript for the type 1 isozyme was detected by Northern blot. The more sensitive RT-PCR showed low levels of type 1 mRNA in the testis and epididymis, with the highest abundance in the proximal caput. Type 2 mRNA of 5alpha-reductase was most abundant in the midcaput, was decreased in the more distal regions, and was more abundant than type 1 mRNA in all epididymal regions except for the proximal caput., Conclusion(s): Both 5alpha-reductase type 1 and type 2 mRNAs are present in the human epididymis. The type 2 isozyme mRNA is predominant, being more highly expressed than the low-abundance type 1 mRNA.
- Published
- 1998
- Full Text
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29. Y-chromosome deletions and male infertility: state of the art and clinical implications.
- Author
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Roberts KP
- Subjects
- Humans, Male, Chromosome Deletion, Infertility, Male genetics, Y Chromosome
- Published
- 1998
30. Prostate cancer: a clinical and basic science review.
- Author
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Long RJ, Roberts KP, Wilson MJ, Ercole CJ, and Pryor JL
- Subjects
- Humans, Male, Prostatic Neoplasms diagnosis, Prostatic Neoplasms therapy, Prostatic Neoplasms physiopathology
- Published
- 1997
31. Immortalization and characterization of a Sertoli cell line from the adult rat.
- Author
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Roberts KP, Banerjee PP, Tindall JW, and Zirkin BR
- Subjects
- Animals, Apoptosis, Bucladesine pharmacology, Cell Division, Cell Line, Transformed, Clusterin, DNA metabolism, Follicle Stimulating Hormone pharmacology, Glycoproteins genetics, Hot Temperature, Keratins analysis, Male, Mutation, RNA, Messenger analysis, Rats, Rats, Sprague-Dawley, Sertoli Cells chemistry, Sertoli Cells drug effects, Simian virus 40, Transferrin genetics, Vimentin analysis, Molecular Chaperones, Sertoli Cells cytology
- Abstract
To facilitate investigations of the regulation of adult Sertoli cell function, we have established a Sertoli cell line from sexually mature Sprague-Dawley rats. The cells were immortalized with the temperature-sensitive mutant of the SV40 virus, tsA255. The tsA255 large T antigen is heat-labile and efficiently promotes propagation of cells at 33 degrees C (permissive temperature) but is inactive at 40 degrees C (nonpermissive temperature). The established clonal Sertoli cell line (ASC-17D) proliferates indefinitely at the permissive temperature. However, within 48 h at the nonpermissive temperature, cell proliferation ceases. ASC-17D cells show positive staining with antibodies to cytokeratin and vimentin, consistent with the Sertoli cell origin of these cells. Transferrin and sulfated glycoprotein (SGP)-2 mRNAs were nearly undetectable in ASC-17D cells cultured at the permissive temperature, but expression of both mRNAs was induced at the nonpermissive temperature. In contrast, SGP-1 was expressed equally at both the permissive and nonpermissive temperatures. There was no increase in either transferrin or SGP-2 with FSH or dibutyryl cAMP (db-cAMP) treatment at the permissive temperature or with FSH treatment at the nonpermissive temperature. However, the steady-state levels of both of these mRNAs were substantially increased in the presence of db-cAMP at the nonpermissive temperature. In contrast, SGP-1 mRNA was not affected by either FSH or db-cAMP. These results suggest that the ASC-17D cell line is derived from adult Sertoli cells and may be useful for the study of adult Sertoli cell function.
- Published
- 1995
- Full Text
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32. The effect of testosterone withdrawal and subsequent germ cell depletion on transferrin and sulfated glycoprotein-2 messenger ribonucleic acid levels in the adult rat testis.
- Author
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Roberts KP, Santulli R, Seiden J, and Zirkin BR
- Subjects
- Animals, Blotting, Northern, Clusterin, Estradiol pharmacology, Leydig Cells metabolism, Male, Nucleic Acid Hybridization, RNA, Messenger genetics, Radioimmunoassay, Rats, Rats, Inbred Strains, Spermatozoa cytology, Testis metabolism, Testosterone analysis, Testosterone metabolism, Time Factors, Glycoproteins genetics, Molecular Chaperones, RNA, Messenger analysis, Sperm Count drug effects, Spermatozoa drug effects, Testis chemistry, Testis cytology, Testosterone pharmacology, Transferrin genetics
- Abstract
We have examined the effects of decreasing intratesticular testosterone concentration and of decreasing germ cell number on levels of transferrin mRNA and sulfated glycoprotein (SGP)-2 mRNA in the adult rat testis. Intact rats received implants of testosterone- and estradiol-filled capsules to suppress LH secretion from the pituitary, thereby suppressing Leydig cell testosterone production. The levels of intratesticular testosterone declined 70% to 20 ng/ml within 3 days, were reduced further to approximately 15 ng/ml by 14 days, and subsequently reached a minimum of about 10 ng/ml. In contrast, the number of elongated spermatids per testis remained unchanged through 14 days, then declined to fewer than 20% of normal between 14 and 28 days, and reached zero by 56 days postimplantation. Likewise, both pachytene spermatocytes and round spermatids declined only after 14 days postimplantation. Northern blots of testicular RNA showed that Sertoli cell transferrin mRNA per testis decreased markedly between 14 and 28 days postimplantation. However, SGP-2 mRNA per testis was unchanged over the time course of the experiment. The decrease in transferrin mRNA, concomitant with germ cell loss, suggests that this mRNA is regulated by the number of germ cells in the testis and not directly by testosterone. In contrast, the constant level of SGP-2 mRNA in the face of reduced intratesticular testosterone and the subsequent loss of germ cells suggests that this mRNA is constitutively maintained in the adult rat testis.
- Published
- 1992
- Full Text
- View/download PDF
33. Characterization of rat transferrin receptor cDNA: the regulation of transferrin receptor mRNA in testes and in Sertoli cells in culture.
- Author
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Roberts KP and Griswold MD
- Subjects
- Amino Acid Sequence, Animals, Base Sequence, Cells, Cultured, Chickens genetics, Follicle Stimulating Hormone pharmacology, Humans, Hypophysectomy, Male, Molecular Sequence Data, RNA, Messenger biosynthesis, RNA, Messenger genetics, Rats, Rats, Inbred Strains, Receptors, Transferrin biosynthesis, Sequence Alignment, Sequence Homology, Nucleic Acid, Testosterone pharmacology, DNA genetics, Gene Expression Regulation drug effects, Iron pharmacology, Receptors, Transferrin genetics, Sertoli Cells metabolism, Testis metabolism, Transferrin metabolism
- Abstract
A 3.4 kilobase cDNA complementary to rat transferrin receptor mRNA has been isolated from an adult rat testis cDNA library. The rat transferrin receptor nucleotide sequence was shown to be 82% similar to the human transferrin receptor sequence over the amino acid coding region and over 90% similar in the sequences known to be responsible for iron regulation in the human mRNA. The mRNA was shown by Northern blot analysis to be regulated by iron levels in Sertoli cells in culture. Iron depletion resulted in at least a 5-fold increase in receptor message in Sertoli cells, as well as in an actively growing testicular cell line (S10-7). The level of transferrin receptor mRNA in cultured Sertoli cells was not influenced by hormones; however, chronic administration of testosterone or FSH to hypophysectomized rats resulted in increased transferrin receptor mRNA levels in the testis. Northern blot analysis of mRNAs from testes of rats synchronized at various stages of the cycle of the seminiferous epithelium showed that transferrin receptor mRNA was differentially regulated throughout the cycle. Northern blots of mRNA from germinal cell populations derived from synchronized tests showed that the message was regulated in the nongerminal cell components of the tubule, most likely the Sertoli cell. The comparison of transferrin receptor mRNA levels in normal testes and testes from hypophysectomized rats, as well as in isolated germinal cells and cultured Sertoli cells, suggested that transferrin receptor mRNA levels were considerably higher in Sertoli cells than in other cell types of the seminiferous tubules.
- Published
- 1990
- Full Text
- View/download PDF
34. Relative sensitivities of environmental legionellae to selective isolation procedures.
- Author
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Roberts KP, August CM, and Nelson JD Jr
- Subjects
- Analysis of Variance, Culture Media, Hot Temperature, Hydrogen-Ion Concentration, Legionella isolation & purification, Water Microbiology
- Abstract
A survey of water samples to determine the efficacy of standard procedures for the isolation of environmental legionellae was conducted. Marked variations in intraspecies resistance to selective agents and treatments were observed, and in experiments with one of the isolates, the response was modified by culture conditions. Five selective procedures incorporating acid (pH 2.2) and heat (50 degrees C, 30 min) treatments, with and without plating on buffered charcoal-yeast extract agar supplemented with vancomycin (5 micrograms/ml), polymyxin B (60 U/ml), and cycloheximide (80 micrograms/ml), caused 5 to 99% decreases in viable counts of pure cultures in water suspensions. The differences in the responses of the cultures to the five treatments were statistically significant. Cells in retained samples of naturally contaminated water from which the original cultures had been isolated were significantly less sensitive than artificially grown isolates. The sensitivities of the laboratory-grown cells to the treatments were affected by the length of incubation on buffered charcoal-yeast extract agar. Whereas acid resistance increased after 24 h of incubation, resistance to the antibiotic mixture decreased.
- Published
- 1987
- Full Text
- View/download PDF
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