26 results match your criteria production ectoplasmic

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A local regulatory network in the testis mediated by laminin and collagen fragments that supports spermatogenesis.

Crit Rev Biochem Mol Biol 2021 Mar 25:1-19. Epub 2021 Mar 25.

The Second Affiliated Hospital and Yuying Children's Hospital, Wenzhou Medical University, Wenzhou, China.

It is almost five decades since the discovery of the hypothalamic-pituitary-testicular axis. This refers to the hormonal axis that connects the hypothalamus, pituitary gland and testes, which in turn, regulates the production of spermatozoa through spermatogenesis in the seminiferous tubules, and testosterone through steroidogenesis by Leydig cells in the interstitium, of the testes. Emerging evidence has demonstrated the presence of a regulatory network across the seminiferous epithelium utilizing bioactive molecules produced locally at specific domains of the epithelium. Read More

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Erection of a New Genus and Species for the Pathogen of Hard Clams 'Quahog Parasite Unknown' (QPX): Mucochytrium quahogii gen. nov., sp. nov.

Protist 2021 Feb 29;172(1):125793. Epub 2021 Jan 29.

School of Marine and Atmospheric Sciences, Stony Brook University, Stony Brook, NY 11794-5000, USA. Electronic address:

Quahog Parasite Unknown (QPX) is a facultative parasite of the hard clam, Mercenaria mercenaria. Although it has been observed in clams since the 1960's and cultivated since the 1990's, conflicting reports on important aspects of its biology have prevented its formal description. 18S rRNA gene sequences identify QPX as a thraustochytrid, but its production of copious mucus is atypical for this group. Read More

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February 2021

Essential role of autophagy in resource allocation during sexual reproduction.

Autophagy 2020 01 16;16(1):18-27. Epub 2019 Jun 16.

State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China.

Sexual reproduction is the most common form of reproduction among eukaryotes, which is characterized by a series of massive cellular or tissue renovations. Recent studies have revealed novel functions of autophagy during sexual reproductive processes, ranging from yeast to mammals. In mammals, autophagy is indispensable for spermatogenesis and oogenesis, and it participates in early embryonic development and maternal-fetus crosstalk to ensure the development of embryos or fetuses. Read More

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January 2020

Planar cell polarity protein Dishevelled 3 (Dvl3) regulates ectoplasmic specialization (ES) dynamics in the testis through changes in cytoskeletal organization.

Cell Death Dis 2019 02 26;10(3):194. Epub 2019 Feb 26.

The Second Affiliated Hospital and Yuying Children's Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, 325027, China.

In the mammalian testes, such as in rats, the directional alignment of polarized elongating/elongated spermatids, in particular step 17-19 spermatids, across the plane of seminiferous epithelium resembles planar cell polarity (PCP) found in hair cells of the cochlea. It is obvious that spermatid PCP is necessary to support the simultaneous development of maximal number of elongating/elongated spermatids to sustain the daily production of > 50 million sperm per adult rat. Studies have shown that the testis indeed expresses multiple PCP proteins necessary to support spermatid PCP. Read More

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February 2019

Nutritional Intake by Ectoplasmic Nets of Schizochytrium aggregatum (Labyrinthulomycetes, Stramenopiles).

Protist 2018 11 18;169(5):727-743. Epub 2018 Jun 18.

Institute for Integrative Neurobiology, Konan University, 8-9-1, Okamoto, Higashinada, Kobe, Hyogo 658-8501, Japan; Faculty of Science and Engineering, Konan University, 8-9-1, Okamoto, Higashinada, Kobe, Hyogo 658-8501, Japan. Electronic address:

Thraustochytrid cells attach to their food via ectoplasmic nets (ENs). Here, we analyzed the cause and effect relationship between the various forms and functions of ENs of Schizochytrium aggregatum. The ENs spread out over a large area forming a fine network to efficiently search for the experimental food source. Read More

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November 2018

New Species of Saprobic Labyrinthulea (=Labyrinthulomycota) and the Erection of a gen. nov. to Resolve Molecular Polyphyly within the Aplanochytrids.

J Eukaryot Microbiol 2018 07 7;65(4):475-483. Epub 2018 Feb 7.

UiT Norges Arktiske Universtiet, BFE, NFH Bygget, Framstredet 6, Tromsø, 9019, Norway.

A culture of a unicellular heterotrophic eukaryote was established from pollen-baited seawater acquired from the nearshore environment in Tromsø, Norway. Light microscopy revealed the production of ectoplasmic nets and reproduction by biflagellated zoospores, as well as binary division. After culturing and subsequent nucleotide extraction, database queries of the isolate's 18S small ribosomal subunit coding region identified closest molecular affinity to Aplanochytrium haliotidis, a pathogen of abalone. Read More

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Cell polarity and cytoskeletons-Lesson from the testis.

Semin Cell Dev Biol 2018 09 6;81:21-32. Epub 2017 Oct 6.

The Mary M. Wohlford Laboratory for Male Contraceptive Research, Center for Biomedical Research, 1230 York Ave, New York, NY 10065, United States. Electronic address:

Cell polarity in the adult mammalian testis refers to the polarized alignment of developing spermatids during spermiogenesis and the polarized organization of organelles (e.g., phagosomes, endocytic vesicles, Sertoli cell nuclei, Golgi apparatus) in Sertoli cells and germ cells to support spermatogenesis. Read More

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September 2018

Nutrient recycling of lipid-extracted waste in the production of an oleaginous thraustochytrid.

Appl Microbiol Biotechnol 2016 May 22;100(10):4711-21. Epub 2016 Mar 22.

Department of Process Engineering and Applied Science, Faculty of Engineering, Dalhousie University, Sexton House E102, Halifax, NS, Canada.

Improving the economics of microalgae production for the recovery of microbial oil requires a comprehensive exploration of the measures needed to improve productivity as well as to reduce the overall processing costs. One avenue for cost reduction involves recycling the effluent waste water remaining after lipid extraction. This study investigates the feasibility of recycling those wastes for growing thraustochytrid biomass, a heterotrophic microalgae, where wastes were generated from the enzymatic extraction of the lipids from the cell biomass. Read More

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Preserved transmembrane protein mobility in polymer-supported lipid bilayers derived from cell membranes.

Anal Chem 2015 Sep 24;87(18):9194-203. Epub 2015 Aug 24.

Department of Applied Physics, Chalmers University of Technology , SE-41296 Gothenburg, Sweden.

Supported lipid bilayers (SLBs) have contributed invaluable information about the physiochemical properties of cell membranes, but their compositional simplicity often limits the level of knowledge that can be gained about the structure and function of transmembrane proteins in their native environment. Herein, we demonstrate a generic protocol for producing polymer-supported lipid bilayers on glass surfaces that contain essentially all naturally occurring cell-membrane components of a cell line while still retaining transmembrane protein mobility and activity. This was achieved by merging vesicles made from synthetic lipids (PEGylated lipids and POPC lipids) with native cell-membrane vesicles to generate hybrid vesicles which readily rupture into a continuous polymer-supported lipid bilayer. Read More

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September 2015

The apical ectoplasmic specialization-blood-testis barrier functional axis is a novel target for male contraception.

Adv Exp Med Biol 2012 ;763:334-355

Center for Biomedical Research, Population Council, New York, New York, USA.

The blood-testis barrier (BTB), similar to other blood-tissue barriers, such as the blood-brain barrier and the blood-retinal barrier, is used to protect the corresponding organ from harmful substances (e.g., xenobiotics) including drugs and foreign compounds. Read More

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Testin and actin are key molecular targets of adjudin, an anti-spermatogenic agent, in the testis.

Spermatogenesis 2011 Apr;1(2):137-146

Center for Biomedical Research; The Population Council; New York, NY USA.

Earlier studies have shown adjudin to cause aspermatogenesis by depleting virtually all germ cells from the seminiferous epithelium, leading to transient infertility; spermatogenesis and fertility were re-established several weeks later after germ cell proliferation and differentiation were reinitiated by spermatogonia. While adjudin is known to exert its initial effects at the apical ectoplasmic specialization (a testis-specific atypical anchoring junction), thereby perturbing spermatid adhesion, its molecular target(s) at this site is not known. Herein, we report the production of a specific antibody against adjudin after this compound was conjugated to an adjuvant (i. Read More

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Cross-talk between tight and anchoring junctions-lesson from the testis.

Adv Exp Med Biol 2008 ;636:234-54

Center for Biomedical Research, The Population Council, New York, NY 10021, USA.

Spermatogenesis takes place in the seminiferous tubules in adult testes such as rats, in which developing germ cells must traverse the seminiferous epithelium while spermatogonia (2n, diploid) undergo mitotic and meiotic divisions, and differentiate into elongated spermatids (1n, haploid). It is conceivable that this event involves extensive junction restructuring particularly at the blood-testis barrier (BTB, a structure that segregates the seminiferous epithelium into the basal and the adluminal compartments) that occurs at stages VII-VIII of the seminiferous epithelial cycle. As such, cross-talk between tight (TJ) and anchoring junctions [e. Read More

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January 2010

Interleukin 1 alpha (IL1A) is a novel regulator of the blood-testis barrier in the rat.

Biol Reprod 2008 Mar 5;78(3):445-54. Epub 2007 Dec 5.

Population Council, Center for Biomedical Research, New York, NY 10065, USA.

Throughout spermatogenesis, leptotene spermatocytes must traverse the blood-testis barrier (BTB) at stages VIII-XI to gain entry into the adluminal compartment for continued development. However, the mechanism underlying BTB restructuring remains somewhat elusive. In this study, interleukin 1 alpha (IL1A) was administered intratesticularly to adult rats in order to assess its effects on spermatogenesis. Read More

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Actin-based dynamics during spermatogenesis and its significance.

J Zhejiang Univ Sci B 2007 Jul;8(7):498-506

The Sperm Laboratory, Institute of Cell Biology and Genetics, School of Life Sciences, Zhejiang University, Hangzhou 310058, China.

Actin can be found in all kinds of eukaryotic cells, maintaining their shapes and motilities, while its dynamics in sperm cells is understood less than their nonmuscle somatic cell counterparts. Spermatogenesis is a complicated process, resulting in the production of mature sperm from primordial germ cell. Significant structural and biochemical changes take place in the seminiferous epithelium of the adult testis during spermatogenesis. Read More

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Isolation and characterization of a novel thraustochytrid-like microorganism that efficiently produces docosahexaenoic acid.

Biotechnol Lett 2006 Feb;28(3):197-202

Laboratory of Environmental Molecular Biology, Graduate School of Environmental Earth Science, Hokkaido University, Sapporo, Kita-ku, 060-0810, Japan.

A thraustochytrid-like microorganism (strain 12B) was isolated from the mangrove area of Okinawa, Japan. On the basis of its ectoplasmic net structure and biflagellate zoospores we determined strain 12B to be a novel member of the phylum Labyrinthulomycota in the kingdom Protoctista. When grown on glucose/seawater at 28 degrees C, it had a lipid content of 58% with docosahexaenoic acid (DHA; 22:6 n-3) at 43% of the total fatty acids. Read More

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February 2006

Mitogen-activated protein kinases, adherens junction dynamics, and spermatogenesis: a review of recent data.

Dev Biol 2005 Oct;286(1):1-15

Population Council, 1230 York Avenue, New York, NY 10021, USA.

Mitogen-activated protein kinases (MAPKs) are important regulators of many cellular processes. In mammalian testes, these kinases are involved in controlling cell division, differentiation, survival and death, and are therefore critical to spermatogenesis. Recent studies have also illustrated their involvement in junction restructuring in the seminiferous epithelium, especially at the ectoplasmic specialization (ES), a testis-specific adherens junction (AJ) type. Read More

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October 2005

Disruption of Sertoli-germ cell adhesion function in the seminiferous epithelium of the rat testis can be limited to adherens junctions without affecting the blood-testis barrier integrity: an in vivo study using an androgen suppression model.

J Cell Physiol 2005 Oct;205(1):141-57

Population Council, New York, New York 10021, USA.

During spermatogenesis, both adherens junctions (AJ) (such as ectoplasmic specialization (ES), a testis-specific AJ type at the Sertoli cell-spermatid interface (apical ES) or Sertoli-Sertoli cell interface (basal ES) in the apical compartment and BTB, respectively) and tight junctions (TJ) undergo extensive restructuring to permit germ cells to move across the blood-testis barrier (BTB) as well as the seminiferous epithelium from the basal compartment to the luminal edge to permit fully developed spermatids (spermatozoa) to be sloughed at spermiation. However, the integrity of the BTB cannot be compromised throughout spermatogenesis so that postmeiotic germ cell-specific antigens can be sequestered from the systemic circulation at all times. We thus hypothesize that AJ disruption in the seminiferous epithelium unlike other epithelia, can occur without compromising the BTB-barrier, even though these junctions, namely TJ and basal ES, co-exist side-by-side in the BTB. Read More

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October 2005

Blood-testis barrier dynamics are regulated by {alpha}2-macroglobulin via the c-Jun N-terminal protein kinase pathway.

Endocrinology 2005 Apr 23;146(4):1893-908. Epub 2004 Dec 23.

Population Council, 1230 York Avenue, New York, New York 10021, USA.

The blood-testis barrier (BTB), in contrast to the blood-brain and blood-retina barriers, is composed of coexisting tight junctions, gap junctions, and basal ectoplasmic specializations, a testis-specific type of adherens junction. Recent studies showed that BTB restructuring that facilitates germ cell migration during spermatogenesis involves proteolysis, an event that is usually restricted to the cell-matrix interface in other epithelia. For instance, a surge in alpha(2)-macroglobulin (alpha(2)-MG), a protease inhibitor produced by Sertoli cells, was detected at the Sertoli-Sertoli and Sertoli-germ cell interface in the epithelium during cadmium chloride-induced BTB disruption in adult rats. Read More

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Sertoli-Sertoli and Sertoli-germ cell interactions and their significance in germ cell movement in the seminiferous epithelium during spermatogenesis.

Endocr Rev 2004 Oct;25(5):747-806

Population Council, Center for Biomedical Research, New York, New York 10021, USA.

Spermatogenesis is the process by which a single spermatogonium develops into 256 spermatozoa, one of which will fertilize the ovum. Since the 1950s when the stages of the epithelial cycle were first described, reproductive biologists have been in pursuit of one question: How can a spermatogonium traverse the epithelium, while at the same time differentiating into elongate spermatids that remain attached to the Sertoli cell throughout their development? Although it was generally agreed upon that junction restructuring was involved, at that time the types of junctions present in the testis were not even discerned. Today, it is known that tight, anchoring, and gap junctions are found in the testis. Read More

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October 2004

Electron microscopic observation of 137Cs-irradiated rat testis: production of basal laminae for germ cells, despite their absence.

J Electron Microsc (Tokyo) 2003 ;52(4):391-7

Department of Anatomy, Yokohama City University School of Medicine, Fukuura 3-9, Kanazawa-ku, Yokohama 236, Japan.

Whole body gamma-ray irradiation of rats with caesium-137 (137Cs) at embryonic day 20 induced marked reduction of the weight of the testis. Body weight and other tissues, however, seemed to remain normal. By light microscopy, complete loss of germ cells was observed in the testis. Read More

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December 2003

Production of long-chain polyunsaturated fatty acids by monoxenic growth of labyrinthulids on oil-dispersed agar medium.

Appl Microbiol Biotechnol 2002 Nov 10;60(3):275-80. Epub 2002 Sep 10.

National Institute of Advanced Industrial Science and Technology, Higashi 1-1, Tsukuba Ibaraki 305-8566, Japan.

A novel method is proposed for the production of long-chain polyunsaturated fatty acids (LCPUFA) by labyrinthulids. The method comprises a monoxenic culture with Psychlobacter phenylpyruvicus, using agar medium in which oil was dispersed. Soybean oil (SBO) was selected as the optimum material for an oil-dispersed agar medium. Read More

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November 2002

Effects of follicle-stimulating hormone on the junction-related Sertoli cell cytoskeleton and daily sperm production in testosterone-treated hypophysectomized rats.

Biol Reprod 1994 Jul;51(1):158-66

Department of Anatomy, University of South Florida College of Medicine, Tampa 33612.

Specialized junctional binding of step 8 spermatids to Sertoli cells is an important spermiogenic event. In the hypophysectomized (Hypox) rat, the daily sperm production (DSP) is reduced and Sertoli cells become binding incompetent. Delayed replacement of testosterone (DT-Hypox) does not restore the normal DSP and Sertoli cells remain binding incompetent. Read More

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Junction-related Sertoli cell cytoskeleton in testosterone-treated hypophysectomized rats.

Biol Reprod 1993 Nov;49(5):1122-32

Department of Anatomy, University of South Florida College of Medicine, Tampa 33612.

Testosterone is the principal hormone necessary for insuring the completion of normal spermatogenesis. However, its precise role in spermatid maturation is not clear. In hypophysectomized rats, testosterone can maintain spermiogenesis if replaced soon after surgery. Read More

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November 1993

Potential sites for the perception of gravity in the acellular slime mold Physarum polycephalum.

Authors:
I Block W Briegleb

Adv Space Res 1989 ;9(11):75-8

DFVLR--Institute for Aerospace Medicine, Cologne, FRG.

Recently a gravisensitivity of the acellular slime mold Physarum polycephalum, which possesses no specialized gravireceptor, could be established by conducting experiments under simulated and under real near weightlessness. In these experiments macroplasmodia showed a modulation of their contraction rhythm followed by regulation phenomena. Until now the perception mechanism for the gravistimulus is unknown, but several findings indicate the involvement of mitochondria: A) During the impediment of respiration the 0g-reaction is inhibited and the regulation is reduced. Read More

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[The vascular pole of hepatocytes: structure, function and pathology].

Authors:
H David P Reinke

Zentralbl Allg Pathol 1986 ;132(2):83-98

Structural and functional subdivision of the hepatocyte into a sinusoidal (vascular) zone, a lateral zone and a peri-canicular zone (adjacent to the bile canaliculi) highlights certain peculiarities of the vascular hepatocyte pole. In contrast to the total cytoplasm, this area is characterized by a high volume of mitochondria, altered peroxisome content, a high concentration of lipids and the absence of Golgi-apparatus. Of critical importance is the sinusoidal cell membrane: at birth, the hepatocyte of the rat bears some 1,000 microvilli, rising to 4,600 in the mature animal. Read More

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December 1986

Surface responses in cultures fibroblasts elicited by ethylenediaminetetraacetic acid.

J Biophys Biochem Cytol 1958 May;4(3):243-50

Cultures of chick heart fibroblasts were perfused with the chelating agent ethylenediaminetetraacetic acid (EDTA). Cellular responses were observed under phase optics and recorded by time-lapse cinemicrography. In interphasic fibroblasts, EDTA induces cellular contraction followed by continuous protrusion and retraction of ectoplasmic blebs ("surface bubbling"), formation of motile vermiform processes, and production of rotatory ectoplasmic swellings. Read More

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