Medicine and Health Sciences Commons^™

Subunit Gating Resulting From Individual Protonation Events In Kir2 Channels, Grigory Maksaev, Michael Bründl-Jirout, Anna Stary-Weinzinger, Eva-Maria Zangerl-Plessl, Sun-Joo Lee, Colin G Nichols

2020-Current year OA Pubs

Inwardly rectifying potassium (Kir) channels open at the 'helix bundle crossing' (HBC), formed by the M2 helices at the cytoplasmic end of the transmembrane pore. Introduced negative charges at the HBC (G178D) in Kir2.2 channels forces opening, allowing pore wetting and free movement of permeant ions between the cytoplasm and the inner cavity. Single-channel recordings reveal striking, pH-dependent, subconductance behaviors in G178D (or G178E and equivalent Kir2.1[G177E]) mutant channels, with well-resolved non-cooperative subconductance levels. Decreasing cytoplasmic pH shifts the probability towards lower conductance levels. Molecular dynamics simulations show how protonation of Kir2.2[G178D], or the D173 pore-lining residues, changes solvation, K

Charge-Voltage Curves Of Shaker Potassium Channel Are Not Hysteretic At Steady State, John Cowgill, Baron Chanda

2020-Current year OA Pubs

Charge-voltage curves of many voltage-gated ion channels exhibit hysteresis but such curves are also a direct measure of free energy of channel gating and, hence, should be path-independent. Here, we identify conditions to measure steady-state charge-voltage curves and show that these are curves are not hysteretic. Charged residues in transmembrane segments of voltage-gated ion channels (VGICs) sense and respond to changes in the electric field. The movement of these gating charges underpins voltage-dependent activation and is also a direct metric of the net free-energy of channel activation. However, for most voltage-gated ion channels, the charge-voltage (Q-V) curves appear to be …

Clustering Of Aromatic Residues In Prion-Like Domains Can Tune The Formation, State, And Organization Of Biomolecular Condensates, Alex S Holehouse, Garrett M Ginell, Daniel Griffith, Elvan Böke

2020-Current year OA Pubs

In immature oocytes, Balbiani bodies are conserved membraneless condensates implicated in oocyte polarization, the organization of mitochondria, and long-term organelle and RNA storage. In

A Pip2 Substitute Mediates Voltage Sensor-Pore Coupling In Kcnq Activation, Yongfeng Liu, Nien-Du Yang, Et Al.

2020-Current year OA Pubs

KCNQ family K

Functional Analysis Of A Critical Glycine (Glycine 12) In Beta-Type Connexins Of Human Skin, Rasheed Bailey

Biology Theses

At least five beta-type connexins are expressed in various layers of the skin (Cx26, Cx30, Cx30.3, Cx31, and Cx32) and all include a glycine residue at position 12. Glycine12 (G12) is located about halfway through the cytoplasmic amino terminus and has been the focus of several studies related to connexin diseases and gap junction channel structure. The importance of this residue is evident in the severity and diversity of diseases associated with amino acid substitutions at G12 including hereditary forms of skin disease, deafness and neuropathy. This study uses bioinformatic analysis in combination with mutational analysis and electrophysiology to better …

Let She Who Has The Womb Speak: Regulating The Use Of Human Oocyte Cryopreservation To The Detriment Of Older Women, Browne C. Lewis

Law Faculty Articles and Essays

This article is divided into three parts. Part I examines the arguments in favor of banning human oocyte cryopreservation. Part II explores the reasons some opponents of human oocyte cryopreservation might give to support restrictions on the use of frozen oocytes. Part III analyzes the possible ethical and legal challenges that may arise in the event that the government seeks to ban the use of frozen oocytes or restrict the use of frozen oocytes based solely on the age of the potential mother.

Effect Of Supplementing Additives In Leptin-Enriched Maturation Medium During In Vitro Maturation And Vitrification Of Goat Oocytes, Reema Talukdar, Ranjan Kumar Biswas, Govindasamy Kadirvel, Bharat Chandra Deka, Sudip Sinha, Lukumoni Buragohain, Birina Bora

Turkish Journal of Veterinary & Animal Sciences

The present study aimed to evaluate the effect of supplementing epidermal growth factor (EGF), insulin-like growth factor-I (IGF-I), fetal bovine serum (FBS), and bovine serum albumin (BSA) in different combinations in a maturation medium (MM) comprising TCM-199 + 5 µg/mL 17-ß estradiol + 5 µg/mL ovine-luteinizing hormone (oLH) + 5 µg/mL pure follicle-stimulating hormone (pFSH) + 100 µM/mL cysteamine containing the best concentration of leptin among 10/20/25/30 ng/mL on in vitro maturation (IVM) and subsequent vitrification of matured goat oocytes. The IVM of oocytes was carried out in a CO2 incubator for 27 h at 38.5 °C. The percentage of …

Effect Of Nicotine On Gene Expression And Developmental Competence Of Bovine Oocytes, Seree Teerapong, Tassanee Faisaikarm, Natakarn Nimsanor, Chinarat Changsangfa, Kornkanok Promthep, Kulnasan Saikhun

The Thai Journal of Veterinary Medicine

Nicotine affected meiosis during oocyte maturation is associated with poor subsequent embryonic development. The aim of this study was to analyze the effects of nicotine exposure during in vitro maturation (IVM) on the outcomes of in vitro fertilization (IVF) and the expression of gene related development of oocytes and embryos. Immature (germinal vesicle, GV) oocytes were randomly cultured in IVM media containing nicotine at concentrations of 0.0 (control) 2.5, 5.0, and 10.0 mM. After culturing for 24 h, oocytes were assessed for their maturation rate, subjected to IVF and mRNA extraction for gene expression analysis using quantitative real time PCR …

A Xenopus Oocyte Model System To Study Action Potentials, Aaron Corbin-Leftwich, Hannah E Small, Helen H Robinson, Carlos A. Villalba-Galea, Linda M Boland

School of Pharmacy Faculty Articles

Action potentials (APs) are the functional units of fast electrical signaling in excitable cells. The upstroke and downstroke of an AP is generated by the competing and asynchronous action of Na+- and K+-selective voltage-gated conductances. Although a mixture of voltage-gated channels has been long recognized to contribute to the generation and temporal characteristics of the AP, understanding how each of these proteins function and are regulated during electrical signaling remains the subject of intense research. AP properties vary among different cellular types because of the expression diversity, subcellular location, and modulation of ion channels. These complexities, in addition to the …

Oocyte Cryopreservation, Esther Gellis

The Science Journal of the Lander College of Arts and Sciences

Anti-mitotic therapies are a form of therapy used to treat cancer patients. The use of these treatments on females can result in fertility complications. Therefore, prior to treatment, women must seek ways to preserve their ability to conceive children after receiving treatment. This study analyzes the outcomes of oocyte cryopreservation and its many variables. Three important variables that can affect the outcome of oocyte cryopreservation are age, cryopreservation method and cryoprotectants. Evidence indicates that human oocyte cryopreservation can enable a woman to preserve her ability to give birth to a healthy child, following anti-mitotic therapies. Hundreds of babies have been …

Construction Of Pooled Oocyte Expression Profiles Of Rhesus Monkey And Mouse For Concurrent Meta-Analyses, Kaj Chokeshaiusaha, Denis Puthier, Catherine Nguyen, Thanida Sananmuang

The Thai Journal of Veterinary Medicine

Concurrent gene expression profiling meta-analysis of in vitro and in vivo matured oocytes among mammals can provide crucial knowledge to assist reproductive technologies. Due to the lack of methodology to prepare oocyte datasets for such analysis, we illustrated the procedures to merge in vitro and in vivo matured oocyte expression profiling datasets of rhesus monkey (Macaca mulatta) and mouse (Mus musculus). Datasets acquired from both species were pooled together based on types of their orthologous genes. To determine the feasibility of constructed pooled data, top orthologous genes differentially expressed between in vitro and in vivo oocytes were identified by Linear …

Correlations Among Oocyte Quality, Hepatic Triacylglycerols, And Some Blood Metabolites In Carora Breed Cows During Early Postpartum, Leandro Rodriguez, Oswaldo Rosendo, Carlos Parraga, Armando Oropeza

Turkish Journal of Veterinary & Animal Sciences

The aim of this study was to assess the relationships of hepatic triacylglycerol (TAG), plasma glucose, plasma cholesterol, and plasma urea nitrogen (PUN) concentrations with the morphological quality of oocytes obtained from 20 Carora breed lactating cows at days 20 and 35 postpartum in a commercial farm. Oocytes were obtained through the technique of transvaginal ultrasound-guided follicle aspiration. Change in body condition score (0.35 vs. 0.44, P = 0.02) and mean plasma cholesterol (3.59 vs. 4.35 mmol/L, P = 0.01) significantly differed between the 2 periods, whereas mean TAG tended to be higher at day 35 after calving (2.29 vs. …

Survivability Of Caprine Oocytes Vitrified In Conventional And Open Pulled Straws, Rameez Ali, Waquar Razzaque, Utsav Sharma, Anil Pandey, Kafil Hussain

Turkish Journal of Veterinary & Animal Sciences

The aim of this study was to compare the efficacy of conventional straw vitrification with open pulled straw vitrification in terms of cryosurvivability and damages caused to the oocytes. Two hundred immature goat cumulus oocyte complexes (COCs) were vitrified in a solution of ethylene glycol, dimethyl sulfoxide, and sucrose using either conventional straws (100 COCs) or open pulled straws (100 COCs). The COCs were warmed and observed for morphological damages and viability after 7 days of preservation in liquid nitrogen. Among the 100 COCs cryopreserved in each case, only 83 COCs were recovered after warming in conventional straw vitrification as …

Endogenous Folate Accumulation In Oocytes And Preimplantation Embryos And Its Epigenetic Implications., Mellissa R W Mann, Andrew J Watson

Obstetrics & Gynaecology Publications

No abstract provided.

Impact Of Male Age On The Outcome Of Assisted Reproductive Technology Cycles Using Donor Oocytes, Eyup Duran, D. Dowling-Lacey, S. Bocca, L. Stadtmauer, S. Oehninger

Eyup Hakan Duran

This study assessed the influence of the age of the male partner on the outcome of oocyte donation cycles. A total of 408 couples participating in 519 consecutive anonymous oocyte donation cycles were examined. Main outcome measures were fertilization rate, embryo quality, clinical pregnancy, implantation, miscarriage and live birth rates, as well as the total reproductive potential, which estimates the outcome from fresh and cryopreserved-thawed embryo transfers. A total of 241 cycles resulted in clinical pregnancy (48.5% of transfers). The mean embryo score for transferred embryos (ESTE) was higher in cycles resulting in pregnancy (P=0.003). Semen volume (P<0.001), sperm …

The Association Of Reproductive Senescence With Mitochondrial Quantity, Function, And Dna Integrity In Human Oocytes At Different Stages Of Maturation., Eyup Duran, Fatma Simsek-Duran, Sergio Oehninger, Howard Jones, Frank Castora

Eyup Hakan Duran

OBJECTIVE: To determine the impact of reproductive aging on oocyte mitochondrial quantity, function, and DNA (mtDNA) integrity. DESIGN: Prospective observational study. SETTING: IVF clinic in a tertiary academic care center. PATIENT(S): One hundred two oocytes from 32 women undergoing IVF. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): Adenosine triphosphate (ATP) levels, mtDNA number, and mtDNA deletion occurrence in individual oocytes. RESULT(S): Oocyte ATP content increases with maturation (786 ± 87 fmol, 1,037 ± 57 fmol, and 1,201 ± 59 fmol for prophase 1 [P1], metaphase 1 [M1], and metaphase 2 [M2] oocytes, respectively), whereas mtDNA copy numbers do not change (64,500 ± …

Use Of Oocytes From Anonymous, Matched, Fertile Donors For Prevention Of Heritable Genetic Diseases, Bradley Van Voorhis, R. Williamson, J. Gerard, D. Hammitt, Craig Syrop

Bradley J Van Voorhis

Heritable genetic diseases can be prevented with the use of donor oocytes. We report our experience in using donor oocytes from anonymous, matched, fertile donors in four women with heritable genetic disorders. Our results show that use of donor oocytes is a practical, successful, and currently available technique for the prevention of genetic disorders.

Menthol Binding And Inhibition Of A7-Nicotinic Acetylcholine Receptors, Abrar Ashoor, Jacob C. Nordman, Daniel Veltri, Keun-Hang Susan Yang, Lina T. Al Kury, Yaroslav M. Shuba, Mohamed Magoub, Frank Christopher Howarth, Bassem Sadek, Amarda Shehu, Nadine Kabbani, Murat Oz

Mathematics, Physics, and Computer Science Faculty Articles and Research

Menthol is a common compound in pharmaceutical and commercial products and a popular additive to cigarettes. The molecular targets of menthol remain poorly defined. In this study we show an effect of menthol on the α7 subunit of the nicotinic acetylcholine (nACh) receptor function. Using a two-electrode voltage-clamp technique, menthol was found to reversibly inhibit α7-nACh receptors heterologously expressed in Xenopus oocytes. Inhibition by menthol was not dependent on the membrane potential and did not involve endogenous Ca2+-dependent Cl− channels, since menthol inhibition remained unchanged by intracellular injection of the Ca2+ chelator BAPTA and perfusion with Ca2+-free bathing solution containing …

A Human Phospholipid Phosphatase Activated By A Transmembrane Control Module, Christian R. Halaszovich, Michael G. Leitner, Angeliki Mavrantoni, Audrey Le, Ludivine Frezza, Anja Feuer, Daniela N. Schreiber, Carlos A. Villalba-Galea, Dominik Oliver

School of Pharmacy Faculty Articles

In voltage-sensitive phosphatases (VSPs), a transmembrane voltage sensor domain (VSD) controls an intracellular phosphoinositide phosphatase domain, thereby enabling immediate initiation of intracellular signals by membrane depolarization. The existence of such a mechanism in mammals has remained elusive, despite the presence of VSP-homologous proteins in mammalian cells, in particular in sperm precursor cells. Here we demonstrate activation of a human VSP (hVSP1/TPIP) by an intramolecular switch. By engineering a chimeric hVSP1 with enhanced plasma membrane targeting containing the VSD of a prototypic invertebrate VSP, we show that hVSP1 is a phosphoinositide-5-phosphatase whose predominant substrate is PI(4,5)P(2). In the chimera, enzymatic activity …

Outer Space And Oocyte Developmental Competence., Andrew J Watson

Obstetrics & Gynaecology Publications

No abstract provided.

Efficient Activation Of Reconstructed Rat Embryos By Cyclin-Dependent Kinase Inhibitors, Robin L. Webb, Kirk A. Findlay, Michael A. Green, Tina L. Beckett, M. Paul Murphy

Molecular and Cellular Biochemistry Faculty Publications

Background

Over the last decade a number of species, from farm animals to rodents, have been cloned using somatic cell nuclear transfer technology (SCNT). This technique has the potential to revolutionize the way that genetically modified animals are made. In its current state, the process of SCNT is very inefficient (<5% success rate), with several technical and biological hurdles hindering development. Yet, SCNT provides investigators with powerful advantages over other approaches, such as allowing for prescreening for the desired level of transgene expression and eliminating the excess production of undesirable wild-type animals. The rat plays a significant role in biomedical research, but SCNT has been problematic for this species. In this study, we address one aspect of the problem by evaluating methods of activation in artificially constructed rat embryos.

Principal Findings

We demonstrate that treatment with a calcium ionophore (ionomycin) combined with a variety of cyclin-dependent kinase inhibitors is an effective way to activate rat embryos. This is in contrast to methods developed for the mouse embryo, which tolerates much less specific chemical treatments. Methods developed to activate …

Regulation Of The Acid-Sensing Ion Channel 1 By Protein Kinase C And Matriptase, Edlira Bashari

All ETDs from UAB

Acid-sensing ion channel 1 (ASIC1) is a member of the Epithelial Na+ channel/ Degenerin (ENaC/Deg) family of ion channels. Like the other members of this family, it is sensitive to the diuretic amiloride. It was previously shown that both normal astrocytes and glioma cells express ASIC1 and some ENaC subunits. However, only high-grade glioma cells exhibit an inward Na+ current that is sensitive to amiloride and to psalmotoxin 1 (PcTX-1), a specific blocker of ASIC1. Amiloride, PcTX-1, and the knockdown of ASIC1 reduce glioma cell migration. The exact composition of the amiloride-sensitive channel and the molecular mechanisms that regulate its …

Oocyte Peptides As Paracrine Tools For Ovarian Stimulation And Oocyte Maturation., David G Mottershead, Andrew J Watson

Obstetrics & Gynaecology Publications

Recent studies report the production and isolation of a stable bioactive recombinant human bone morphogenetic protein 15 (rhBMP15) that is appropriately processed in HEK-293 cells and activates the SMAD 1/5/8 pathway in mouse granulosa cell cultures. Further, the purified rhBMP15 induces the expression of genes associated with cumulus expansion. Thanks to recent research, we have a greater understanding of the importance of the dialogue that occurs between the oocyte and the granulosa cell layer with regard to regulating folliculogenesis and the acquisition of oocyte developmental competence and maturation. BMP15 is one of the critical components of these intra-follicular communication pathways. …

Coupling Between The Voltage-Sensing And Phosphatase Domains Of Ci-Vsp, Carlos A. Villalba-Galea, Francesco Miceli, Maurizio Taglialatela, Francisco Bezanilla

School of Pharmacy Faculty Articles

The Ciona intestinalis voltage sensor-containing phosphatase (Ci-VSP) shares high homology with the phosphatidylinositol phosphatase enzyme known as PTEN (phosphatase and tensin homologue deleted on chromosome 10). We have taken advantage of the similarity between these proteins to inquire about the coupling between the voltage sensing and the phosphatase domains in Ci-VSP. Recently, it was shown that four basic residues (R11, K13, R14, and R15) in PTEN are critical for its binding onto the membrane, required for its catalytic activity. Ci-VSP has three of the basic residues of PTEN. Here, we show that when R253 and R254 (which are the homologues …

Cryopreservation Of Immature Porcine Oocytes Using Open Pulled Straw Vitrification, Theerawat Tharasanit, Sasitorn Rungarunlert, Mongkol Techakumphu

The Thai Journal of Veterinary Medicine

The aims of this study were to investigate the meiotic competence of immature porcine oocytes following open pulled straw (OPS) vitrification and warming and also to test the efficiency of the pretreatment of immature oocytes with CB prior to OPS vitrification. Experiment 1, cumulus oocyte complexes (COCs) were randomly assigned to OPS vitrification, cryoprotectant (CPA) toxicity test and non-CPA/non-vitrified controls. Experiment 2, the COCs were treated with 7.5 μg/ml CB for 30 min. The oocytes were either immediately fixed or further incubated in a CB-free medium for 5 h, non-CB treated COCs served as controls. Experiment 3, CB-pretreated COCs were …

Effects Of Oocyte Source On The Developmental Competence Of In Vitro Matured Goat Oocytes Fertilized By The Intracytoplasmic Sperm Injection Technique, Abu Nasar Md. Aminoor Rahman, Ramli Bin Abdullah, Wan Embong Wan-Khadijah

Turkish Journal of Veterinary & Animal Sciences

This study evaluated the effects of oocyte source on in vitro maturation (IVM) and embryo developmental competence in goats by the intracytoplasmic sperm injection (ICSI) technique. Oocytes were obtained either by laparoscopic ovum pick-up (LOPU) or by slicing of abattoir ovaries. The donor does used for LOPU were superstimulated and their estrus was synchronized. Recovered oocytes from both sources were cultured in microdrops of IVM medium in the presence of CO2 (5%) at 38.5 °C in a CO2 incubator for 27 h. The ICSI was performed with immobilized sperm on the lid of a culture dish (35 mm) under an …

Revealing Genes Associated With Vitellogenesis In The Liver Of The Zebrafish (Danio Rerio) By Transcriptome Profiling., Liraz Levi, Irena Pekarski, Ellen Gutman, Paolo Fortina, Terry Hyslop, Jakob Biran, Berta Levavi-Sivan, Esther Lubzens

Department of Pathology, Anatomy, and Cell Biology Faculty Papers

BACKGROUND: In oviparous vertebrates, including fish, vitellogenesis consists of highly regulated pathways involving 17beta-estradiol (E2). Previous studies focused on a relatively small number of hepatic expressed genes during vitellogenesis. This study aims to identify hepatic genes involved in vitellogenesis and regulated by E2, by using zebrafish microarray gene expression profiling, and to provide information on functional distinctive genes expressed in the liver of a vitellogenic female, using zebrafish as a model fish. RESULTS: Genes associated with vitellogenesis were revealed by the following paired t-tests (SAM) comparisons: a) two-month old vitellogenic (Vit2) females were compared with non-vitellogenic (NV) females, showing 825 …

Bovine Oocytes And Early Embryos Express Staufen And Elavl Rna-Binding Proteins., M D Calder, P Madan, A J Watson

Obstetrics & Gynaecology Publications

RNA-binding proteins (RBP) influence RNA editing, localization, stability and translation and may contribute to oocyte developmental competence by regulating the stability and turnover of oogenetic mRNAs. The expression of Staufen 1 and 2 and ELAVL1, ELAVL2 RNA-binding proteins during cow early development was characterized. Cumulus-oocyte complexes were collected from slaughterhouse ovaries, matured, inseminated and subjected to embryo culture in vitro. Oocyte or preimplantation embryo pools were processed for RT-PCR and whole-mount immunofluorescence analysis of mRNA expression and protein distribution. STAU1 and STAU2 and ELAVL1 mRNAs and proteins were detected throughout cow preimplantation development from the germinal vesicle (GV) oocyte to …

Oocyte Cytoplasmic Maturation: A Key Mediator Of Oocyte And Embryo Developmental Competence., A J Watson

Obstetrics & Gynaecology Publications

Efforts have intensified to successfully mature and inseminate oocytes in vitro and then culture ensuing embryos to transferable stages from a large number of mammalian species. Success varies, but generally even for the most successful species it is only possible to obtain a maximum of a 40 to 50% development of zygotes to the blastocyst stage. Reduced oocyte developmental competence is suggested as a primary reason for the reduced potential of in vitro-produced embryos. The vast majority of in vitro-matured oocytes are meiotically competent; however, many do not attain an optimal oocyte diameter before insemination. Variations in oocyte in vitro …

Regulation Of Human Cystic Fibrosis Transmembrane Conductance Regulator (Cftr) By Serum- And Glucocorticoid-Inducible Kinase (Sgk1), J. Denry Sato, M. Christine Chapline, Renee Thibodeau, Raymond A. Frizzell, Bruce A. Stanton

Dartmouth Scholarship

Background: Serum- and glucocorticoid-inducible kinase-1 (SGK1) increases CFTR Cl currents in Xenopus oocytes by an unknown mechanism. Because SGK increases the plasma membrane expression of other ion channels, the goal of this paper was to test the hypothesis that SGK1 stimulates CFTR Cl currents by increasing the number of CFTR Cl channels in the plasma membrane. Methods: CFTR Cl currents were measured in Xenopus oocytes by the two-electrode voltage clamp technique, and CFTR in the plasma membrane was determined by laser scanning confocal microscopy. Results: wt-SGK1 stimulated CFTR Cl currents by 42% and increased the amount of CFTR in the …