scholarly journals Receptor function of mouse sperm surface galactosyltransferase during fertilization.

1985 ◽  
Vol 101 (4) ◽  
pp. 1501-1510 ◽  
Author(s):  
L C Lopez ◽  
E M Bayna ◽  
D Litoff ◽  
N L Shaper ◽  
J H Shaper ◽  
...  
Keyword(s):  
Zona Pellucida ◽  
Dorsal Surface ◽  
Mouse Sperm ◽  
Sperm Surface ◽  
Sperm Binding ◽  
Total Inhibition ◽  
Dependent Inhibition ◽  
Dose Dependent Inhibition ◽  
Plasma Membrane Domain ◽  
Dose Dependent

Past studies from this laboratory have suggested that mouse sperm binding to the egg zona pellucida is mediated by a sperm galactosyltransferase (GalTase), which recognizes and binds to terminal N-acetylglucosamine (GlcNAc) residues in the zona pellucida (Shur, B. D., and N. G. Hall, 1982, J. Cell Biol. 95:567-573; 95:574-579). We now present evidence that directly supports this mechanism for gamete binding. GalTase was purified to homogeneity by sequential affinity-chromatography on GlcNAc-agarose and alpha-lactalbumin-agarose columns. The purified enzyme produced a dose-dependent inhibition of sperm binding to the zona pellucida, relative to controls. To inhibit sperm/zona binding, GalTase had to retain its native conformation, since neither heat-inactivated nor Mn++-deficient GalTase inhibited sperm binding. GalTase inhibition of sperm/zona binding was not due to steric blocking of an adjacent sperm receptor on the zona, since GalTase could be released from the zona pellucida by forced galactosylation with UDPGal, and the resulting galactosylated zona was still incapable of binding sperm. In control experiments, when UDPGal was replaced with the inappropriate sugar nucleotide, UDPglucose, sperm binding to the zona pellucida remained normal after the adsorbed GalTase was washed away. The addition of UDPGal produced a dose-dependent inhibition of sperm/zona binding, and also dissociated preformed sperm/zona adhesions by catalyzing the release of the sperm GalTase from its GlcNAc substrate in the zona pellucida. Under identical conditions, UDP-glucose had no effect on sperm binding to the zona pellucida. The ability of UDPGal to dissociate sperm/zona adhesions was both time- and temperature-dependent. UDPGal produced nearly total inhibition of sperm/zona binding when the zonae pellucidae were first galactosylated to reduce the number of GalTase binding sites. Finally, monospecific anti-GalTase IgG and its Fab fragments produced a dose-dependent inhibition of sperm/zona binding and concomitantly blocked sperm GalTase catalytic activity. Preimmune IgG or anti-mouse brain IgG, which also binds to the sperm surface, had no effect. The sperm GalTase was localized by indirect immunofluorescence to a discrete plasma membrane domain on the dorsal surface of the anterior head overlying the intact acrosome. These results, along with earlier studies, show clearly that sperm GalTase serves as a principal gamete receptor during fertilization.

Differences between antigenic determinants of pig and cat zona pellucida proteins

Reproduction ◽  
2000 ◽  
pp. 15-23 ◽  
Author(s):  
K Jewgenow ◽  
M Rohleder ◽  
I Wegner
Keyword(s):  
In Vitro Fertilization ◽  
Zona Pellucida ◽  
Antigenic Determinants ◽  
Vitro Fertilization ◽  
Contraceptive Vaccine ◽  
Sperm Binding ◽  
Dependent Inhibition ◽  
Dose Dependent Inhibition ◽  
Dose Dependent

Despite many efforts, the control of reproduction in feral cat populations is still a problem in urban regions around the world. Immunocontraception is a promising approach; thus the present study examined the suitability of the widely used pig zona pellucida proteins (pZP) for contraception in feral domestic cats. Purified zona pellucida proteins obtained from pig and cat ovaries were used to produce highly specific antisera in rabbits. Antibodies against pZP raised in rabbits or lions were not effective inhibitors of either in vitro sperm binding (cat spermatozoa to cat oocytes) or in vitro fertilization in cats, whereas antibodies against feline zona pellucida proteins (fZP) raised in rabbits showed a dose-dependent inhibition of in vitro fertilization. Immunoelectrophoresis, ELISA and immunohistology of ovaries confirmed these results, showing crossreactivity of anti-fZP sera to fZP and to a lesser extent to pZP, but no interaction of anti-pZP sera with fZP. It is concluded that cat and pig zonae pellucidae express a very small number of shared antigenic determinants, making the use of pZP vaccine in cats questionable. A contraceptive vaccine based on feline zona pellucida determinants will be a better choice for the control of reproduction in feral cats if immunogenity can be achieved.

scholarly journals A role for mouse sperm surface galactosyltransferase in sperm binding to the egg zona pellucida.

1982 ◽  
Vol 95 (2) ◽  
pp. 574-579 ◽  
Author(s):  
B D Shur ◽  
N G Hall
Keyword(s):  
Zona Pellucida ◽  
Milk Protein ◽  
Preceding Paper ◽  
Transferase Activity ◽  
Mouse Sperm ◽  
Sperm Surface ◽  
Galactosyl Transferase ◽  
Sperm Binding ◽  
Beta Galactosidase

Past studies have suggested that mouse sperm surface galactosyltransferase may participate during fertilization by binding N-acetylglucosamine (GlcNAc) residues in the zona pellucida. In this paper, we examined further the role of sperm surface galactosyltransferase in mouse fertilization. Two reagents that specifically perturb sperm surface galactosyltransferase activity both inhibit sperm-zona binding. The presence of the milk protein alpha-lactalbumin specifically modifies the substrate specificity of sperm galactosyltransferase away from GlcNAc and towards glucose and simultaneously inhibits sperm binding to the zona pellucida. Similarly, UDP-dialdehyde inhibits sperm binding to the zona pellucida and sperm surface galactosyl-transferase activity to identical degrees. Of five other sperm enzymes assayed, four are unaffected by UDP-dialdehyde, and one is affected only slightly. Covalent linkage of UDP-dialdehyde to sperm dramatically inhibits binding to eggs, while treatment of eggs with UDP-dialdehyde has no effect on sperm binding. Heat-solubilized or pronase-digested zona pellucida inhibit sperm-zona binding, and they can be glycosylated by sperm with UDP-galactose. Sperm are also able to glycosylate intact zona pellucida with UDP-galactose. Thus, solubilized and intact zona pellucida act as substrates for sperm surface GlcNAc:galactosyltransferases. Finally, pretreatment of eggs with beta-N-acetylglucosaminidase inhibits sperm binding by up to 86%, while under identical conditions, pretreatment with beta-galactosidase increases sperm binding by 55%. These studies, in conjunction with those of the preceding paper dealing with surface galactosyltransferase changes during capacitation, directly suggest that galactosyltransferase is at least one of the components necessary for sperm binding to the zona pellucida.

Antioxidant effects and in vitro cytotoxicity on human cancer cell lines of flavonoid-rich Flamboyant (Delonix regia (Bojer) Raf.) flower extract

2020 ◽  
Vol 21 ◽  
Author(s):  
Putthiporn Khongkaew ◽  
Phanphen Wattanaarsakit ◽  
Konstantinos I. Papadopoulos ◽  
Watcharaphong Chaemsawang
Keyword(s):  
Cell Line ◽  
Cell Lines ◽  
Cancer Cell ◽  
Leukemia Cell ◽  
Leukemia Cell Line ◽  
Flower Extract ◽  
Dependent Inhibition ◽  
Dose Dependent Inhibition ◽  
Murine Leukemia Cell ◽  
Dose Dependent

Background: Cancer is a noncommunicable disease with increasing incidence and mortality rates both worldwide and in Thailand. Its apparent lack of effective treatments is posing challenging public health issues. Introduction: Encouraging research results indicating probable anti-cancer properties of the Delonix regia flower extract (DRE) have prompted us to evaluate the feasibility of developing a type of product for future cancer prevention or treatment. Methods and Results: In the present report, using High Performance Liquid Chromatography (HPLC), we demonstrate in the DRE, the presence of high concentrations of three identifiable flavonoids, namely rutin 4.15±0.30 % w/w, isoquercitrin 3.04±0.02 %w/w, and myricetin 2.61±0.01 % w/w respectively while the IC50 of DPPH and ABTS assay antioxidation activity was 66.88±6.30 µg/ml and 53.65±7.24 µg/ml respectively. Discussion: Our cancer cell line studies using the MTT assay demonstrated DREs potent and dose dependent inhibition of murine leukemia cell line (P-388: 35.28±4.07% of cell viability remaining), as well as of human breast adenocarcinoma (MCF-7), human cervical carcinoma (HeLa), human oral cavity carcinoma (KB), and human colon carcinoma (HT-29) cell lines in that order of magnitude. Conclusion: Three identifiable flavonoids (rutin, isoquercitrin and myricetin) with high antioxidation activity and potent and dose dependent inhibition of murine leukemia cell line and five other cancer cell lines were documented in the DRE. The extract’s lack of cytotoxicity in 3 normal cell lines is a rare advantage not usually seen in current antineoplastic agents. Yet another challenge of the DRE was its low dissolution rate and long-term storage stability, issues to be resolved before a future product can be formulated.

Investigation on the antibacterial activity of electronic cigarette liquids (ECLs): a proof of concept study

2020 ◽  
Vol 21 ◽  
Author(s):  
Virginia Fuochi ◽  
Massimo Caruso ◽  
Rosalia Emma ◽  
Aldo Stivala ◽  
Riccardo Polosa ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Bacterial Species ◽  
A549 Cells ◽  
Bactericidal Effect ◽  
Minimal Bactericidal Concentration ◽  
Viability Assay ◽  
Dependent Inhibition ◽  
Dose Dependent Inhibition ◽  
Dose Dependent

Background: The key ingredients of e-cigarettes liquid are commonly propane-1,2-diol (also called propylene glycol) and propane-1,2,3-triol (vegetal glycerol) and their antimicrobial effects are already established. The nicotine and flavors which are often present in e-liquids can interfere with the growth of some microorganisms. Objective: The effect of the combining these elements in e-liquids is unknown. The aim of the study was to investigate the possible effects of these liquids on bacterial growth in the presence or absence of nicotine and flavors. Methods: Susceptibilities of pathogenic strains (Klebsiella pneumoniae, Staphylococcus aureus, Pseudomonas aeruginosa, Acinetobacter baumannii, Escherichia coli, Enterococcus faecalis and Sarcina lutea) were studied by means of a multidisciplinary approach. Cell viability and antioxidant assays were also evaluated. Results: All e-liquids investigated showed antibacterial activity against at least one pathogenic strain. A higher activity was correlated to the presence of flavors and nicotine. Discussion: In most cases the value of minimal bactericidal concentration is equal to the value of minimal inhibitory concentration showing that these substances have a bactericidal effect. This effect was observed in concentrations up to 6.25% v/v. Antioxidant activity was also correlated to presence of flavors. Over time, the viability assay in human epithelial lung A549 cells showed a dose-dependent inhibition of cell growth. Conclusion: Our results have shown that flavors considerably enhance the antibacterial activity of propane-1,2-diol and propane-1,2,3-triol. This study provides important evidence that should be taken into consideration in further investigative approaches, to clarify the different sensitivity of the various bacterial species to e-liquids, including the respiratory microbiota, to highlight the possible role of flavors and nicotine.

scholarly journals In VitroActivities of Hexaazatrinaphthylenes against Leishmania spp.

2015 ◽  
Vol 59 (5) ◽  
pp. 2867-2874 ◽  
Author(s):  
Atteneri López-Arencibia ◽  
Daniel García-Velázquez ◽  
Carmen M. Martín-Navarro ◽  
Ines Sifaoui ◽  
María Reyes-Batlle ◽  
...  
Keyword(s):  
Therapeutic Agents ◽  
Content Type ◽  
Inhibition Effect ◽  
Intracellular Amastigotes ◽  
Dependent Inhibition ◽  
Leishmania Spp ◽  
Dose Dependent Inhibition ◽  
Dose Dependent ◽  
Potential Use

ABSTRACTThein vitroactivity of a novel group of compounds, hexaazatrinaphthylene derivatives, against two species ofLeishmaniais described in this study. These compounds showed a significant dose-dependent inhibition effect on the proliferation of the parasites, with 50% inhibitory concentrations (IC50s) ranging from 1.23 to 25.05 μM against the promastigote stage and 0.5 to 0.7 μM against intracellular amastigotes. Also, a cytotoxicity assay was carried out to in order to evaluate the possible toxic effects of these compounds. Moreover, different assays were performed to determine the type of cell death induced after incubation with these compounds. The obtained results highlight the potential use of hexaazatrinaphthylene derivatives againstLeishmaniaspecies, and further studies should be undertaken to establish them as novel leishmanicidal therapeutic agents.

μ-Opiate Receptors in Neuronal Primary Cultures from Cerebral Cortex

1990 ◽  
Vol 17 (3) ◽  
pp. 177-181
Author(s):  
Peter S. Eriksson ◽  
Elisabeth Hansson ◽  
Lars Rönnbäck
Keyword(s):  
Cerebral Cortex ◽  
Primary Cultures ◽  
Opiate Receptors ◽  
Neuronal Cultures ◽  
Camp Accumulation ◽  
Dependent Inhibition ◽  
Dose Dependent Inhibition ◽  
Neuronal Primary Cultures ◽  
Dose Dependent ◽  
Μ Receptor

The presence of μ-opioid receptors was demonstrated as effects of receptor stimulation on PGE1-induced cAMP accumulation in neuronal-enriched primary cultures from rat cerebral cortex. Morphine was used as a μ-receptor agonist. There was a dose-dependent inhibition of the PGE1-stimulated cAMP accumulation by morphine, blocked by the μ-receptor antagonist naloxone. These findings suggest that these neuronal cultures express μ-receptors, possibly connected to adenylate cyclase via an inhibitory Gi-protein. The probable use of functional μ-receptors in neurotoxicological tests is discussed.

EFFECT OF INTRAVENTRICULAR ADMINISTRATION OF NORADRENALINE ON WATER DIURESIS IN GOATS

1975 ◽  
Vol 66 (3) ◽  
pp. 375-383 ◽  
Author(s):  
G. VANDEPUTTE-VAN MESSOM ◽  
G. PEETERS
Keyword(s):  
Intraventricular Administration ◽  
Excretion Ratio ◽  
Dose Response Relationship ◽  
Water Diuresis ◽  
3Rd Ventricle ◽  
Dependent Inhibition ◽  
Dose Dependent Inhibition ◽  
High Doses ◽  
Excretion Rates ◽  
Dose Dependent

SUMMARY During water diuresis in conscious goats, noradrenaline (NA), its antagonists phentolamine, phenoxybenzamine and propranolol and also atropine were administered into the 3rd ventricle. The subsequent effects on water diuresis and on the excretion rates of Na+, K+ and Cl− were investigated. Infusion of NA into the 3rd ventricle induced a strong and significant antidiuretic response and a decrease in the Na+: K+ excretion ratio; these effects were dose-dependent. High doses of NA produced a significant increase in urinary K+ excretion. Similar results were observed after i.v. administration of arginine-vasopressin. Pretreatment with phentolamine injected into the 3rd ventricle produced a dose-dependent inhibition of the NA-induced antidiuretic effects. Phenoxybenzamine also blocked the response to NA but a dose-response relationship was not apparent. Atropine and propranolol did not block the response to NA.

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