“Mouse Spermatozoa in High Concentrations of Glycerol: Chemical Toxicity vs Osmotic Shock at Normal and Reduced Oxygen Concentrations” and “Effect of Osmolality and Oxygen Tension on the Survival of Mouse Sperm Frozen to Various Temperatures in Various Concentrations of Glycerol and Raffinose”

Cryobiology ◽  
2001 ◽  
Vol 42 (2) ◽  
pp. 151
Author(s):  
Igor I. Katkov ◽  
Nadezhda Katkova ◽  
John K. Critser ◽  
Peter Mazur ◽  
Chihiro Koshimoto ◽  
...  
Keyword(s):  
Oxygen Tension ◽  
Osmotic Shock ◽  
Chemical Toxicity ◽  
Mouse Sperm ◽  
High Concentrations ◽  
Oxygen Concentrations

Mouse Spermatozoa in High Concentrations of Glycerol: Chemical Toxicity vs Osmotic Shock at Normal and Reduced Oxygen Concentrations

Cryobiology ◽  
1998 ◽  
Vol 37 (4) ◽  
pp. 325-338 ◽  
Author(s):  
Igor I. Katkov ◽  
Nadezhda Katkova ◽  
John K. Critser ◽  
Peter Mazur
Keyword(s):  
Osmotic Shock ◽  
Chemical Toxicity ◽  
High Concentrations ◽  
Oxygen Concentrations

129 DEVELOPMENTAL COMPETENCE OF PORCINE OOCYTES AFTER IN VITRO MATURATION AND IN VITRO CULTURE UNDER COMPARATIVE OXYGEN TENSION

2011 ◽  
Vol 23 (1) ◽  
pp. 169
Author(s):  
J. T. Kang ◽  
M. Atikuzzaman ◽  
D. K. Kwon ◽  
S. J. Park ◽  
S. J. Kim ◽  
...  
Keyword(s):  
In Vitro Culture ◽  
Oxygen Tension ◽  
Embryo Development ◽  
In Vitro Maturation ◽  
Polar Body ◽  
Mrna Abundance ◽  
Developmental Competence ◽  
Multiple Genes ◽  
Oxygen Concentrations

The in vitro developmental abilities of porcine oocytes are generally increasing steadily at a similar ratio to those of in vivo embryos. However, it has been suggested that the in vitro culture system for the development of porcine embryos is not optimal. In this study, we investigated the effect of 2 oxygen concentrations (5 and 20%) on porcine embryo development during in vitro maturation and in vitro culture and analyzed differences in gene expression of resulting blastocysts. Oocytes were recovered by aspiration of slaughterhouse ovaries and then matured in tissue culture medium (TCM) 199 supplemented with 10% porcine follicular fluid (pFF), epidermal growth factor (EGF), insulin, pyruvate, cystine, and gonadotropin. Matured oocytes were then activated parthenogenetically, cultured in PZM-3 media for 7 days. In vitro maturation (M group) of oocytes was carried out under two oxygen concentration (5 and 20%) in terms of nuclear maturation (polar body extrusion; Exp. 1). The developmental differences between 5% oxygen culture group and 20% oxygen culture group during in vitro culture (C group) of embryos after parthenogenetic activation was investigated in terms of first cleavage and blastocyst formation (Exp. 2). Relative mRNA abundance of multiple genes in blastocysts was analyzed for transcript abundance of genes related with metabolism (GLUT1, LDHA), oxidative response (MnSOD, GPX1), apoptosis (BAX, Bcl2), and developmental competence (CCNB1, IGF2R; Exp. 3). The results show there were no significant differences in maturation rate between 2 oxygen concentrations during in vitro maturation (83 v. 86%). It was thought that cumulus cells surrounding oocytes might have attenuated oxidative stress, but number of resulting blastocysts were (P < 0.05) increased in 5% IVC group when compared with 20% IVC group (18.67 v. 14.09%, respectively). Moreover, the M20C5 group (23.01%) had a beneficial effect on in vitro culture compared with M5C5 (14.32%), M5C20 (10.30%), and M20C20 (17.88%) groups. Total cell numbers were not significantly different among groups. According to mRNA abundance data of multiple genes, each group altered the expression of genes in various patterns. Therefore, it could be concluded that high oxygen tension during in vitro maturation and low oxygen tension during in vitro culture might alter the expression of multiple genes related to oocyte competence and improve (P < 0.05) embryo development, but not blastocyst quality. This study was supported by MKE (#2009-67-10033839, #2009-67-10033805), NRF (#M10625030005-508-10N25), BK21 for Veterinary Science, IPET (#109023-05-1-CG000), and Hanhwa L&C.

scholarly journals Isolation and Characterization of NaCl-Sensitive Mutants of Caulobacter crescentus

2003 ◽  
Vol 69 (6) ◽  
pp. 3029-3035 ◽  
Author(s):  
Luiz Fernando G. Zuleta ◽  
Val�ria C. S. Italiani ◽  
Marilis V. Marques
Keyword(s):  
Caulobacter Crescentus ◽  
Osmotic Shock ◽  
Promoter Regions ◽  
Isolation And Characterization ◽  
Lipopolysaccharide Biosynthesis ◽  
Severe Reduction ◽  
Mutant Strains ◽  
High Concentrations ◽  
Severe Growth

ABSTRACT An attempt to characterize Caulobacter crescentus genes important for the response to high concentrations of NaCl was initiated by the isolation of mutants defective in survival in the presence of 85 mM NaCl. A transposon Tn5 library was screened, and five strains which contained different genes disrupted by the transposon were isolated. Three of the mutants had the Tn5 in genes involved in lipopolysaccharide biosynthesis, one had the Tn5 in the nhaA gene, which encodes a Na+/H+ antiporter, and one had the Tn5 in the ppiD gene, which encodes a peptidyl-prolyl cis-trans isomerase. All the mutant strains showed severe growth arrest in the presence of 85 mM NaCl, but only the nhaA mutant showed decreased viability under these conditions. All the mutants except the nhaA mutant showed a slightly reduced viability in the presence of 40 mM KCl, but all the strains showed a more severe reduction in viability in the presence of 150 mM sucrose, suggesting that they are defective in responding to osmotic shock. The promoter regions of each disrupted gene were cloned in lacZ reporter vectors, and the pattern of expression in response to NaCl and sucrose was determined; this showed that both agents induced ppiD and nhaA gene expression but did not induce the other genes. Furthermore, the ppiD gene was not induced by heat shock, indicating that it does not belong to the σ32 regulon, as opposed to what was observed for its Escherichia coli homolog.

Oxygen recognition in aerotactic behaviour of Azospirillum brasilense Cd

1986 ◽  
Vol 32 (11) ◽  
pp. 829-834 ◽  
Author(s):  
Orly Reiner ◽  
Yaacov Okon
Keyword(s):  
Azospirillum Brasilense ◽  
Spectral Studies ◽  
Antimycin A ◽  
Terminal Oxidases ◽  
Cytochrome O ◽  
Low Concentrations ◽  
High Concentrations ◽  
Cytochrome D ◽  
Oxygen Concentrations

Oxygen recognition in aerotactic behaviour of Azospirillum brasilense was studied. Spectral studies of membrane preparations of A. brasilense Cd revealed three terminal oxidases: cytochromes aa3, o, and d. The possible involvement of each of these cytochromes in oxygen reception was evaluated. Since neither reducing the level of cytochrome aa3 in the bacteria nor inhibition of cytochrome aa3 by low concentrations of cyanide affected aerotaxis, it was concluded that cytochrome aa3 is not the oxygen receptor. Cytochromes o and d are inhibited by high concentrations of cyanide which also inhibit aerotaxis. Of these two, cytochrome o seems more likely to be the oxygen receptor, since antimycin A, which inhibits the reduction of this cytochrome (but not that of cytochrome d), completely inhibited aerotaxis. By using tethered cells, it was demonstrated that A. brasilense is microaerophilic, as it is attracted to oxygen concentrations lower than those present in the air (20%).

Zoospore Germination in Blastocladiella Emersonii

1972 ◽  
Vol 10 (2) ◽  
pp. 315-333
Author(s):  
D. R. SOLL ◽  
D. R. SONNEBORN
Keyword(s):  
Osmotic Shock ◽  
Cell Structure ◽  
Ion Selectivity ◽  
Choline Chloride ◽  
Exposure Period ◽  
Monovalent Cation ◽  
Continuous Exposure ◽  
Initial Exposure ◽  
Cell Conversion ◽  
High Concentrations

Zoospore germination in B. emersonii is accompanied by a series of abrupt, dramatic changes in cell structure. Membranes appear to be variously involved in many of these changes. Germination is subject to simple manipulations of the ionic environment: swimming zoospores can be maintained for long periods in the buffered CaCl2 solution into which they are initially released, whereas dilution into a solution containing KCl and MgCl2 in addition to CaCl2 results in rapid, semisynchronous germination of entire zoospore populations. The control of germination by ionic means has been characterized in the following ways: (a) Very brief (40 S to 2 min) exposure to GS, followed by replacement with buffered CaCl2 is as effective as continuous exposure in eliciting rapid germination of the entire zoospore population. (b) The effective component of GS is KCl: GS lacking KCl does not elicit rapid germination; conversely, buffered KCl alone is as effective as complete GS in eliciting germination. (c) Zoospore populations are sensitive to KCl concentration; as the KCl concentration is reduced, the proportion of cells which undergo rapid germination is also reduced. (d) At optimal concentration (5 x 10-2 M), the following salts are equally as effective as KCl in eliciting germination: KI, KBr, NaCl, CsCl, RbCl, and choline chloride. (e) At high concentrations (2.5-5 x 10-2 M), CaCl2 and MgCl2 elicit semi-synchronous conversion of zoospores to round cells, but only after sizeable delays (v. KCl). Conversion of round cells to germlings does not occur in MgCl2 and is enormously delayed in CaCl2; when formed, the germ tubes appear abnormal. (f) Monovalent cation salts of complex divalent anions (sulphate, tartrate, molybdate, tungstate) also exhibit decreased effectiveness (v. KCl) in eliciting germination. (g) The monovalent cation salts NH4Cl and LiCl, the divalent cation salt MnCl2, and the non-ionic compound sucrose are all ineffective in eliciting rapid germination. When in combination with an effective elicitor (KCl), LiCl totally blocks germination, MnCl2 and sucrose lead to significant delays in zoospore to round cell conversion, while NH4Cl has no effect on the population kinetics. (h) LiCl can block germination even when added after the completion of the otherwise sufficient early exposure period to GS (see (a) above). The blocking effect of LiCl can be almost completely reversed by replacement with KCl. On the basis of this characterization it is concluded that (1) rapid germination is not elicited simply by osmotic shock; rather, the cells are capable of responding to other (especially ionic) properties of their chemical environment; and (2) while brief exposure to KCl is sufficient to elicit germination, there are evidently other ion-sensitive steps occurring after the completion of this initial exposure period. Implications of the results in relation to the regular ion selectivity patterns found in other ion-dependent systems, the possible site(s) of action of the eliciting compounds, and the newly discovered ‘zoospore maintenance factor’ are discussed.

Evidence for an effector role of endothelin in closure of the ductus arteriosus at birth

1992 ◽  
Vol 70 (7) ◽  
pp. 1061-1064 ◽  
Author(s):  
Flavio Coceani ◽  
Lois Kelsey ◽  
Eric Seidlitz
Keyword(s):  
Oxygen Concentration ◽  
Oxygen Tension ◽  
Ductus Arteriosus ◽  
Critical Role ◽  
Blood Oxygen ◽  
Endothelin 1 ◽  
A Value ◽  
Near Term ◽  
Oxygen Concentrations

The ductus arteriosus is a special muscular shunt that in the fetus allows blood to bypass the unexpanded lungs. It closes rapidly after birth and this event is initiated by the physiologic rise in blood oxygen tension. Endothelin-1 has been proposed by us as a local mediator for oxygen after demonstrating that it is formed within the ductus and is a potent ductus constrictor. To confirm this possibility, we have now measured the release of endothelin-1 from the isolated ductus of near-term fetal lambs at different oxygen concentrations of the medium. In addition, using the same preparation, we have examined the effect on contractile tone of compounds interfering with the synthesis (phosphoramidon, 50 μM) and action (BQ123, 1 μM) of endothelin-1. We report that release of endothelin-1 from the ductus tends to increase with the oxygen concentration up to a value mimicking the neonatal condition. Phosphoramidon and, to a greater degree, BQ123 inhibit the contraction of the vessel to oxygen. These results implicate endothelin-1 as the effector agent for oxygen in the ductus and, by extension, assign to this peptide a critical role in the closure of the vessel at birth.Key words: ductus arteriosus closure, oxygen, endothelin.

scholarly journals Regulation of Lipid Synthesis inBradyrhizobium japonicum: Low Oxygen Concentrations Trigger Phosphatidylinositol Biosynthesis

1998 ◽  
Vol 64 (5) ◽  
pp. 1963-1966 ◽  
Author(s):  
Yin Tang ◽  
Rawle I. Hollingsworth
Keyword(s):  
Oxygen Tension ◽  
Bradyrhizobium Japonicum ◽  
Lipid Synthesis ◽  
Low Oxygen ◽  
Free Living ◽  
Plant Lipid ◽  
Oxygen Concentrations

ABSTRACT Lowering oxygen tension in free-living Bradyrhizobium japonicum resulted in a dramatic switch of membrane chemistry in which phosphatidylcholine, the predominant lipid in aerated cultures, was no longer synthesized and phosphatidylethanolamine became the major lipid. Besides this change, phosphatidylinositol, a typical plant lipid rarely found in bacteria, was also synthesized.

UM ENSAIO SOBRE A ADAPTAÇÃO DE Pygocentrus nattereri À VARIAÇÃO SAZONAL DAS ÁGUAS DO LAGO MAMIRAUÁ – RESERVA DE DESENVOLVIMENTO SUSTENTÁVEL MAMIRAUÁ

2008 ◽  
Vol 1 (1) ◽  
pp. 65-70
Author(s):  
Mauricio Camargo ◽  
Helder Queiroz
Keyword(s):  
Sustainable Development ◽  
Habitat Use ◽  
Low Oxygen ◽  
Vital Functions ◽  
Pygocentrus Nattereri ◽  
High Concentrations ◽  
Concentration Levels ◽  
Flooding Period ◽  
Oxygen Concentrations

This study investigates habitat use of Pygocentrus nattereri Kner, 1858 at the highest m om ents of the flooding period (July) and during the low water period (October), and evaluates the hability to survive low oxygen concentrations and the production of sulphidric gas in the waters of Mamirauá Lake – Mamirauá Sustainable Development Reserve. 12 experimental samplings were taken at six sites in Mamirauá Lake, and at Paraná Apara. With two experiments, carried out inside the waterbodies and in aquarium , we evaluated the effect of low D.O. concentration levels in the water on P. nattereri. Results show that even under restraining conditions of oxygenation in the water, P. nattereri are able to keep their vital functions. Different situation is observed when the waters of Mamirauá Lake produce high concentrations of suphidric gas, and the individuals of P. nattereri die under this circunstance.

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