Chromatin-mediated cortical granule redistribution is responsible for the formation of the cortical granule-free domain in mouse eggs

AbstractA cortical granule-free domain (CGFD) overlies the metaphase chromatin in fully mature mouse eggs. Although a chromatin-induced localized release of cortical granules (CG) during maturation is thought to be a major contributing factor to its formation, there are indications that CG redistribution may also be involved in generating the CGFD. We performed experiments to determine the relative contributions of CG exocytosis and redistribution in generating the CGFD. We found that the CGFD-inducing activity was not specific to female germ cell chromatin and was heat stable but sensitive to DNase and protease treatment. Surprisingly, chelation of egg intracellular Ca2+ levels did not prevent CGFD formation in response to microinjection of exogenous chromatin, suggesting that development of the CGFD was not a result of CG exocytosis. This finding was confirmed by the lack of CG exudate on the plasma membrane surface of the injected eggs and the absence of conversion of ZP2 to ZP2f during formation of the new CGFD. Moreover, clamping intracellular Ca2+ did not prevent the formation of the CGFD during oocyte maturation, but did inhibit the maturation-associated release of CGs between metaphase I and II. Results of these experiments suggest that CG redistribution is the dominant factor in formation of the CGFD

Gloria Swanson (1897-1983). El retrat d’un ascens i un desterrament cinematogràfic

Abstract not availabl

Spontaneous parity and charge-conjugation violations at real isospin and imaginary baryon chemical potentials

The phase structure of two-flavor QCD is investigated at real isospin and imaginary quark chemical potentials by using the Polyakov-loop extended Nambu--Jona-Lasinio model. In the region, parity symmetry is spontaneously broken by the pion superfluidity phase transition, whereas charge-conjugation symmetry is spontaneously violated by the Roberge-Weiss transition. The chiral (deconfinement) crossover at zero isospin and quark chemical potentials is a remnant of the parity (charge-conjugation) violation. The interplay between the parity and charge-conjugation violations are analyzed, and it is investigated how the interplay is related to the correlation between the chiral and deconfinement crossovers at zero isospin and quark chemical potentials.Comment: 12 pages, 18 figures. Typos were revised. Symbols /P and /C were added in Figures 8a and 8b. Colors of the figures were changed. Some sentences were added and revise

A simple and rapid chemiluminescence assay for on-site analysis of paraquat using a portable luminometer

Paraquat (N,N′-dimethyl-4,4′-bipyridinium dichloride) is one of the most widely used herbicides owing to its high efficacy and low environmental persistence. However, because paraquat has significant acute toxicity, fatalities are often caused by accidental or voluntary ingestion of paraquat. In consideration of the strong toxicity and fast-Acting property of paraquat, on-site analysis at accident scenes should be effective in facilitating immediate medical treatment. In this study, a simple and rapid chemiluminescence assay using a portable luminometer was developed for on-site analysis of paraquat. The proposed assay is based on luminol chemiluminescence detection of superoxide anion radical resulting from the redox reaction between paraquat and dithiothreitol. Intense chemiluminescence was observed after mixing of paraquat and dithiothreitol in the presence of luminol. Because the chemiluminescence intensity was proportional to the concentration of paraquat, a quantitative measurement of paraquat was possible. The calibration curve for standard paraquat solution was linear from 0.025 to 2.5 μM with the correlation coefficient of 0.992; the detection limit (blank + 3SD) was 22 nM. The proposed assay was applied to determine paraquat in beverage samples after a cation exchange clean-up procedure. Given that the portable luminometer used in this study is small and lightweight, the proposed assay should be useful for on-site analysis of paraquat

No association between polymorphisms in the BDNF gene and age at onset in Huntington disease

BACKGROUND: Recent evidence suggests that brain-derived neurotrophic factor (BDNF) is an attractive candidate for modifying age at onset (AO) in Huntington disease (HD). In particular, the functional Val66Met polymorphism appeared to exert a significant effect. Here we evaluate BDNF variability with respect to AO of HD using markers that represent the entire locus. METHODS: Five selected tagging polymorphisms were genotyped across a 65 kb region comprising the BDNF gene in a well established cohort of 250 unrelated German HD patients. RESULTS: Addition of BDNF genotype variations or one of the marker haplotypes to the effect of CAG repeat lengths did not affect the variance of the AO. CONCLUSION: We were unable to verify a recently reported association between the functional Val66Met polymorphism in the BDNF gene and AO in HD. From our findings, we conclude that neither sequence variations in nor near the gene contribute significantly to the variance of AO