scholarly journals Sperm aster in rabbit zygotes: its structure and function.

1976 ◽  
Vol 69 (3) ◽  
pp. 539-547 ◽  
Author(s):  
F J Longo
Keyword(s):  
Endoplasmic Reticulum ◽  
Smooth Endoplasmic Reticulum ◽  
Tritiated Thymidine ◽  
Structure And Function ◽  
Close Apposition ◽  
Male And Female ◽  
Autoradiographic Analysis ◽  
And Function ◽  
Dense Aggregation ◽  
Sperm Aster

Microscope observations of rabbit zygotes demonstrate that a sperm aster forms in association with the male pronucleus approximately 1 h postinsemination and consists of two regions. One, the centrosphere, contains a dense aggregation of cisternae of smooth endoplasmic reticulum and microtubules. The second consists of fascicles of microtubules which emanate from the centrosphere. Fertilized rabbit eggs were cultured in medium containing colcemid in order to determine its effects on various events of fertilization, such as movements of the male and female pronuclei and DNA synthesis. No evidence was obtained to indicate that a sperm aster is formed in colcemid-treated zygotes. In addition, migration and close apposition of the pronuclei do not take place. Breakdown of the pronuclear envelopes and condensation of the maternally and paternally derived chromosomes occur even though the pronuclei fail to migrate centrad. Autoradiographic analysis of the synthesis of DNA by both pronuclei demonstrates that their migration into close apposition to one another is not required for the incorporation of tritiated thymidine.

Oxidative protein folding in the mammalian endoplasmic reticulum

2004 ◽  
Vol 32 (5) ◽  
pp. 655-658 ◽  
Author(s):  
C.E. Jessop ◽  
S. Chakravarthi ◽  
R.H. Watkins ◽  
N.J. Bulleid
Keyword(s):  
Endoplasmic Reticulum ◽  
Mammalian Cells ◽  
Redox State ◽  
Structure And Function ◽  
Reduced Form ◽  
Secretory Proteins ◽  
Oxidative Protein Folding ◽  
Disulphide Bonds ◽  
And Function ◽  
Substrate Proteins

Native disulphide bonds are essential for the structure and function of many membrane and secretory proteins. Disulphide bonds are formed, reduced and isomerized in the endoplasmic reticulum of mammalian cells by a family of oxidoreductases, which includes protein disulphide isomerase (PDI), ERp57, ERp72, P5 and PDIR. This review will discuss how these enzymes are maintained in either an oxidized redox state that allows them to form disulphide bonds in substrate proteins or a reduced form that allows them to perform isomerization and reduction reactions, how these opposing pathways may co-exist within the same compartment and why so many oxidoreductases exist when PDI alone can perform all three of these functions.

Analysis of Ca2+ uptake into the smooth endoplasmic reticulum of permeabilised sternal epithelial cells during the moulting cycle of the terrestrial isopodPorcellio scaber

2002 ◽  
Vol 205 (13) ◽  
pp. 1935-1942 ◽  
Author(s):  
Monica Hagedorn ◽  
Andreas Ziegler
Keyword(s):  
Endoplasmic Reticulum ◽  
Epithelial Cells ◽  
Smooth Endoplasmic Reticulum ◽  
Cyclopiazonic Acid ◽  
Crystal Formation ◽  
Porcellio Scaber ◽  
Intracellular Compartments ◽  
Electron Microscopical ◽  
And Function ◽  
Moulting Cycle

SUMMARYIn terrestrial isopods, large amounts of Ca2+ are transported across anterior sternal epithelial cells during moult-related deposition and resorption of CaCO3 deposits. Because of its toxicity and function as a second messenger, resting cytosolic Ca2+ levels must be maintained below critical concentrations during epithelial Ca2+transport, raising the possibility that organelles play a role during Ca2+ transit. We therefore studied the uptake of Ca2+into Ca2+-sequestering organelles by monitoring the formation of birefringent calcium oxalate crystals in permeabilised anterior and posterior sternal epithelium cells of Porcellio scaber during Ca2+-transporting and non-transporting stages of the moulting cycle using polarised-light microscopy. The results indicate ATP-dependent uptake of Ca2+ into organelles. Half-maximal crystal growth at a Ca2+ activity, aCa, of 0.4 μmol l-1 and blockade by cyclopiazonic acid suggest Ca2+uptake into the smooth endoplasmic reticulum by the smooth endoplasmic reticulum Ca2+-ATPase. Analytical electron microscopical techniques support this interpretation by revealing the accumulation of Ca2+-containing crystals in smooth membranous intracellular compartments. A comparison of different moulting stages demonstrated a virtual lack of crystal formation in the early premoult stage and a significant fivefold increase between mid premoult and the Ca2+-transporting stages of late premoult and intramoult. These results suggest a contribution of the smooth endoplasmic reticulum as a transient Ca2+ store during intracellular Ca2+ transit.

scholarly journals The Potential Role of Seminal Plasma in the Fertilization Outcomes

2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Justyna Szczykutowicz ◽  
Anna Kałuża ◽  
Maria Kaźmierowska-Niemczuk ◽  
Mirosława Ferens-Sieczkowska
Keyword(s):  
Seminal Plasma ◽  
Potential Role ◽  
Human Sperm ◽  
Structure And Function ◽  
Regulatory Mechanisms ◽  
Male And Female ◽  
Healthy Pregnancy ◽  
Male Gametes ◽  
And Function

For human infertility both male and female factors may be equally important. Searching for molecular biomarkers of male infertility, neglected for decades, and the attempts to explain regulatory mechanisms of fertilization become thus extremely important. Apart from examination of the structure and function of male gametes, also the possible importance of seminal plasma components should be considered. In this article we discuss data that indicate for the substantial significance of active seminal plasma components for conception and achievement of healthy pregnancy. Seminal plasma impact on the storage and cryopreservation of human and animal sperm and regulatory role of glycodelin on human sperm capacitation as well as hypothesized course of female immune response to allogenic sperm and conceptus has been discussed. The possible involvement of carbohydrates in molecular mechanism of fetoembryonic defense has been also mentioned.

Alleviation of Hippocampal Endoplasmic Reticulum Stress by Allomyrina dichotoma Larvae Extract

2018 ◽  
Vol 46 (03) ◽  
pp. 633-650 ◽  
Author(s):  
Jongwan Kim ◽  
Md. Nazmul Haque ◽  
Tae-Won Goo ◽  
Il Soo Moon
Keyword(s):  
Endoplasmic Reticulum ◽  
Er Stress ◽  
Hippocampal Neurons ◽  
Ethanol Extract ◽  
Structure And Function ◽  
Synaptic Proteins ◽  
Obese Mice ◽  
Neuron Culture ◽  
Hippocampal Cultures ◽  
And Function

In the brain, endoplasmic reticulum (ER) stress results in synaptic dysfunction and eventually leads to neurodegeneration. Allomyrina dichotoma larvae are a Chinese ethnomedicine and are widely used in East Asia. In the present study, we investigated the ability of ethanol extract of A. dichotoma larvae (ADE) to improve synaptic structure and function by activating unfolded protein response (UPR) under ER stress in animal and neuron culture models. ER stress was induced in obese mice fed a high fat diet (HFD) or by treating dissociated cultures of rat embryonic (E19) hippocampal neurons with tunicamycin (TM). Western blot and real-time or conventional RT-PCR were performed to analyze the expressions of ER stress marker proteins. In dissociated hippocampal cultures, immunocytochemistry was performed for synaptic proteins, and cultures were stained with styryl dye FM1-43 to assess presynaptic activities. In HFD-fed obese mice, ADE efficiently reduced the expressions of ER stress markers, such as, xbp-1, chop, atf4, erdi4, and eIf2a, and those of the ER chaperone/foldases Bip/grp78, Ero-1l, and PDI. Unconventionally spliced xbp-1s mRNA was not detected. In primary rat hippocampal cultures under ER stress, ADE significantly lowered the nuclear expression of CHOP, inhibited the downregulations of postsynaptic proteins, such as, GluN2A, GluN2B, and PSD-95, and maintained the pool size of recycling presynaptic vesicles. The study shows that ADE potently suppressed the induction of ER stress and maintained the structure and function of hippocampal neurons, and suggests that ADE is a potentially valuable food supplement and preventive therapeutic for ER stress-related nervous disorders.

Sex-related Differences in Gene Expression in Salivary Glands of BALB/c Mice

2005 ◽  
Vol 84 (2) ◽  
pp. 160-165 ◽  
Author(s):  
N.S. Treister ◽  
S.M. Richards ◽  
M.J. Lombardi ◽  
P. Rowley ◽  
R.V. Jensen ◽  
...  
Keyword(s):  
Gene Expression ◽  
Sexual Dimorphism ◽  
Salivary Glands ◽  
Structure And Function ◽  
Differentially Expressed ◽  
Male And Female ◽  
Tissue Specific ◽  
Total Rna ◽  
Males And Females ◽  
And Function

Sex-related differences exist in the structure and function of the major glands in a variety of species. Moreover, many of these variations appear to be unique to each tissue. We hypothesized that this sexual dimorphism is due, at least in part, to gland-specific differences in gene expression between males and females. Glands were collected from male and female BALB/c mice (n = 5/sex/experiment), and total RNA was isolated. Samples were analyzed for differentially expressed mRNAs with CodeLink microarrays, and data were evaluated by GeneSifter. Our results demonstrate that significant (P < 0.05) sex-related differences exist in the expression of numerous genes in the major salivary glands, and many of these differences were tissue-specific. These findings support our hypothesis that sex-related differences in the salivary glands are due, at least in part, to tissue-specific variations in gene expression.

scholarly journals Arterial structure and function during and after long-duration spaceflight

2020 ◽  
Vol 129 (1) ◽  
pp. 108-123 ◽  
Author(s):  
Stuart M. C. Lee ◽  
L. Christine Ribeiro ◽  
David S. Martin ◽  
Sara R. Zwart ◽  
Alan H. Feiveson ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Cardiovascular Health ◽  
Structure And Function ◽  
Low Earth Orbit ◽  
Earth Orbit ◽  
Male And Female ◽  
Long Duration ◽  
Arterial Structure ◽  
And Function

Carotid artery structure and stiffness did not change on average in astronauts during long-duration spaceflight (<12 mo), despite increased oxidative stress and inflammation. Most oxidative stress and inflammation biomarkers returned to preflight levels soon after landing. Brachial artery structure and function also were unchanged by spaceflight. In this group of healthy middle-aged male and female astronauts, spaceflight in low Earth orbit does not appear to increase long-term cardiovascular health risk.

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