A5028303892- Reproductive Biology and Fertility
- Sperm and Testicular Function
- Ovarian function and disorders
- Animal Genetics and Reproduction
- Pluripotent Stem Cells Research
- Birth, Development, and Health
- Protein Kinase Regulation and GTPase Signaling
- Trace Elements in Health
- Ion Channels and Receptors
- Genetics, Aging, and Longevity in Model Organisms
- Ion channel regulation and function
- Genetic and Clinical Aspects of Sex Determination and Chromosomal Abnormalities
- Magnesium in Health and Disease
- Renal and related cancers
- Reproductive Physiology in Livestock
- Plant Stress Responses and Tolerance
- Microtubule and mitosis dynamics
- Pancreatic function and diabetes
- Plant Micronutrient Interactions and Effects
- Seed Germination and Physiology
- Genetic and phenotypic traits in livestock
- Signaling Pathways in Disease
- Assisted Reproductive Technology and Twin Pregnancy
- Circadian rhythm and melatonin
- CRISPR and Genetic Engineering
University of Massachusetts Amherst
2016-2025
Azabu University
2012
University of Córdoba
2010
The University of Queensland
2010
Baystate Medical Center
2009-2010
Cornell University
2010
KU Leuven
2003
Tufts University
1999
Harvard University
1989-1992
Veterinary Medical Teaching Hospital
1986
Egg activation, which is the first step in initiation of embryo development, involves both completion meiosis and progression into mitotic cycles. In mammals, fertilizing sperm delivers activating signal, consists oscillations free cytosolic Ca2+ concentration ([Ca2+]i). Intracytoplasmic injection (ICSI) a technique that vitro fertilization clinics use to treat myriad male factor infertility cases. Importantly, some patients who repeatedly fail ICSI also induce egg activation are, therefore,...
Several phospholipase C (PLC) isoforms have been found in male and female mammalian gametes, splicing of PLCdelta4 are predominantly expressed testis. Here we report that mice which the gene had disrupted either produced few small litters or were sterile. In vitro fertilization studies showed insemination with PLCdelta4-/- sperm resulted significantly fewer eggs becoming activated calcium transients associated absent delayed. unable to initiate acrosome reaction, an exocytotic event required...
Activation of the egg by sperm is first, vital stage embryogenesis. The protein PLCζ has been proposed as physiological agent that triggers Ca2+ oscillations normally initiate Consistent with this, recombinant induces in eggs and debilitating mutations PLCZ1 gene are associated infertility men. However, there no evidence knockout encoding abolishes ability to induce eggs. Here, we show derived from Plcz1-/- male mice fail trigger eggs, cause polyspermy thus demonstrate these oscillations....
One of the most important processes in fertilization is fusion egg and sperm; however, molecular mechanisms involved this process are not well understood. So far, using genetic approaches, only two proteins have been demonstrated to be necessary for process: Izumo sperm CD9 egg. Here we demonstrate that produced by Tssk6 (Sstk)-null mice present defects prevent successful eggs vitro zona-pellucida-free eggs. a member testis-specific serine kinase family expressed postmeiotically male germ...
A sperm-specific phospholipase (PL) C, termed PLCzeta, is proposed to be the soluble sperm factor that induces Ca(2+) oscillations in mammalian eggs and, thus, initiates egg activation vivo. We report from transgenic mice expressing short hairpin RNAs targeting PLCzeta mRNA have reduced amounts of protein. Sperm derived these trigger patterns following fertilization vitro terminate prematurely. Consistent with perturbation finding mating founder males females results lower rates and no...
We have previously demonstrated that initiation of intracellular calcium ([Ca2+]i) oscillations in mouse eggs signals activation or apoptotic death depending on the age which are induced. To extend these studies, were aged vitro to 24, 32, and 40 h post-hCG injected with sperm cytosolic factor (SF), adenophostin A, (intracytoplasmic injection), times at signs apoptosis first appeared examined. These treatments, induced [Ca2+]i oscillations, caused fragmentation other programmed cell as early...
During meiotic maturation, numerous cytoplasmic and nuclear events take place that prepare the oocytes for fertilization. These changes are initiated by an increase in activity of several kinases, most notably maturation-promoting factor, also called histone H1 kinase. Another kinase, mitogen-activated protein (MAP) is stimulated during this period. In study, we investigated role MAP kinase bovine oocyte maturation. First, kinetics activation kinases maturation were assessed simultaneously...
Sperm-induced calcium (Ca2+) changes were examined in zona pellucida-intact, mature bovine eggs injected with the fluorescent Ca2+ indicator fura-2 dextran (fura-2 D). Fifty four percent (37/68) of dye-injected, inseminated fertilized and 43% (16/37) exhibited elevations during time measurement. All (16/16) but none unfertilized (0/31) showed intracellular elevations. Six 13 that later found to be at recordings did not show sperm-induced (8/16) a single rise as response sperm penetration...
In this study we evaluated nuclear and ooplasmic maturation of prepuberal calf oocytes to determine a possible cause for their low developmental competency. Calf resumed meiosis arrested at the MII stage rates similar that adult animals; however, zygotes derived from cleaved developed significantly lower rates. Ooplasmic was assessed during oocyte fertilization. Transmission electron microscopy revealed majority exhibited some delay in organelle migration redistribution following maturation....
Fertilization in mammals is associated with the generation of intracellular calcium ([Ca2+]i) oscillations. The site of, or mechanism(s) utilized by, sperm to initiate and maintain these Ca2+ responses not known. In this study, we tested hypothesis that a factor from capable, upon release into oocyte's cytosol, initiating A factor, prepared porcine semen, was injected mouse oocytes bovine eggs had been loaded fura-2 dextran, fluorescent indicator. resulting were monitored compared those...
Zona pellucida (ZP)–induced acrosome reaction in sperm is a required step for mammalian fertilization. However, the precise mechanism of remains unclear. We previously reported that PLCδ4 involved ZP-induced mouse sperm. Here we have monitored Ca2+ responses single sperm, and report [Ca2+]i increase response to ZP, which essential driving vivo, absent PLCδ4−/− Progesterone, another physiological inducer reaction, failed induce sustained increases consequently was partially inhibited. In...
Our previous studies have shown that oocytes collected from prepubertal calves lack developmental competence. The overall objective of this study was to assess causes by comparing biochemical and physiologic changes during in vitro maturation ovaries adult cattle at slaughter superstimulated (<6 mo old) either laporotomy or ultrasound-guided follicular aspiration. Activity and/or concentrations maturation-promoting factor (MPF), mitogen-activated protein kinase (MAPK), inositol...
The influence of electrical stimulation on the level intracellular Ca2+ in bovine oocytes, as well activation and extent parthenogenetic development, was investigated. Mature oocytes were electrically stimulated at 29 hr maturation, concentration determined with indicator fura-2 dextran (fura-2 D). response to a given pulse variable. Oocytes responded either no rise from baseline (approximately 12 nM), short-duration (from nM 300 nM) that returned within 2 min pulse, or long-duration...
Changes in the intracellular concentration of free calcium ([Ca(2+)]i) regulate diverse cellular processes including fertilization. In mammalian eggs, [Ca(2+)]i changes induced by sperm unfold a pattern periodical rises, also known as oscillations. The source Ca(2+) during oscillations is endoplasmic reticulum ([Ca(2+)]ER), but it presently unknown how [Ca(2+)]ER regulated. Here, we show using mouse eggs that variety agonists, PLCζ, SrCl2 and thimerosal, provoke simultaneous opposite cause...
Injection of a porcine cytosolic sperm factor (SF) or testicular extract into mammalian eggs triggers oscillations intracellular free calcium ([Ca2+]i) similar to those initiated by fertilization. To elucidate whether SF activates the phosphoinositide (PI) pathway, mouse were incubated with U73122, an inhibitor events leading phospholipase C (PLC) activation and/or PLC itself. In both cases, U73122 blocked ability induce [Ca2+]i oscillations, although it did not inhibit Ca2+ release caused...
In mammalian fertilization, inositol 1,4,5-trisphosphate receptor (IP3R)-dependent Ca2+ release is a crucial signaling event that originates from the vicinity of sperm-egg interaction and spreads as wave throughout egg cytoplasm. While it known released by type 1 IP3R in cortex, potential involvement other isoform types responsible for rise mouse (interior) their spatial distribution are not known. addition, biochemical basis has been definitively established development increased...