Quantitation of Sertoli cell-germ cell desmosome gap junctions in relation to meiotic divisions in the male rat.

Desmosome-gap (D-G) junctions were quantified in relation to germ cell meiosis in the male, specifically to test the hypothesis that the loss of these junctions is related to successful passage of cells through diplotene phase of Meiosis I and the two cytokineses that follow. Such a hypothesis has been proposed as the cause for the resumption of meiosis that occurs prior to ovulation in the female. D-G junctions were quantified in pachytene spermatocytes (stage XII), diplotene spermatocytes (stage XII), secondary spermatocytes (stage XIV) and step 1 spermatids (stage I). These were referred to as the cells of interest as compared with spermatocytes (zygotene spermatocytes, zygotene spermatocytes, pachytene spermatocytes, pachytene spermatocytes) in the same stages, respectively, that served as controls termed control cells. Since gap junctions are not easily recognized in the average sectioned profile of a desmosome-gap junction, only the desmosomal component was quantified. The data were expressed as both numbers and length of junctions per tubule, per cell profile and per unit lineal membrane length to overcome errors inherent in the methodologies utilized. There was no indication that numbers of junctions changed specifically in the cells of interest after passage through diplotene suggesting that these junctions do not have a comparable role in meiotic continuance in the male as proposed for the female. Interestingly, the control cells always showed greater numbers and length of junctions than the cells of interest suggesting that junction may relate more to the period of initiation of meiosis than to its continuance.     

Evidence for the mannosylation of a non-histone protein in monkey liver chromatin

Summary Mannose is incorporated in monkey liver chromatin by the means of a nuclear membrane mannosyl-transferase.¹⁴C-labelled chromatin is dissociated either by sulfuric acid or 6 M urea and 0.4 M GuCl. The fractions then enriched in non-histone¹⁴C-labelled proteins are excluded from Ultro-gel AcA 202, their analysis in SDS-polyacrylamide gel electrophoresis shows that radioactivity fits with one major protein band, confirming the presence of at least a non-histone protein labelled with mannose in monkey liver chromatin, with an apparent molecular weight of 13 000.     

Differentiation between the somatostatin inhibition and the post-somatostatin rebound observed on growth hormone secretion in vitro

A rebound in growth hormone secretion following somatostatin treatment has been shown in several systems where somatostatin suppresses secretion of the hormone. We have developed an in vitro system in which isolated and cultured pituitary cells were perfused after mild trypsinization. After washing, these cells retained their sensitivity and secreted growth hormone (GH) in response to physiological activators (norepinephrine, dopamine, serotonin) or inhibitors (somatostatin) as well as pharmacological activators (PGE2). The variation in GH secretion occurred within a minute after commencement of the infusion and was as rapidly reversible and repeatable minutes later. During somatostatin infusion the GH secretion was not totally suppressed (residual secretion (mean +/- S.D.) 34 +/- 7%). After the infusion a rapid rebound in GH secretion occurred, reaching levels in excess of the pretreatment value of 138 +/- 13%. This rebound effect occurred at doses higher than (10(-10)M) but not at lower doses, even when significant inhibition was observed. The inhibitory effect is of greater magnitude than the rebound effect (rebound = inhibition X 57 +/- 7% (mean +/- S.D.)). Furthermore, rebound was not enhanced by prolongation of somatostatin infusion. These latter results indicate that the rebound in secretion cannot be explained on the sole basis of storage of intracellular GH during somatostatin infusion and in fact suggest the involvement of a process of GH degradation and/or an inhibition of GH synthesis.     

Effets du rubidium et du césium sur la croissance et la nutrition minerale des characees

Résumé Le rubidium et le césium introduits à l'état de chlorure dans le milieu de culture ont à faible dose un effet stimulant sur la croissance de Chara fragilis et de Chara vulgaris. La résistance de ces végétaux à l'action toxique des deux ions est accrue par l'addition de potassium au milieu.Les analyses chimiques confirment que le rubidium et le césium sont antagonistes vis-à-vis du potassium et du sodium alors qu'ils ne modifient pas de manière significative le taux de calcium.

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Chara fragilis and Chara vulgaris were cultivated in a natural medium containing rubidium and caesium as chloride.The growth of Characeae was increased after culture in the solutions containing Rb and Cs in small amount. The resistance to the toxic effects of these two ions is enhanced if potassium chloride is added to the medium.Quantitative analyses indicate that Rb and Cs decrease the rate of Na and K but have no significative influence on the rate of Ca.

Université de Dijon, Laboratoire de Nutrition minérale des Végétaux     

Utilization of cellulosic materials through enzymatic hydrolysis. II. Preliminary assessment of an integrated processing scheme

An integrated processing scheme is described for the conversion of a cellulosic waste (newsprint) to sugars by enzymatic hydrolysis and then to ethanol and yeast by fermentation. The unconverted solids are burned to produce process energy requirements and surplus electrical power. Preliminary designs and cost studies are developed to provide a rough perspective on the potential economic feasibility of this method of cellulose utilization.     

JQ-1 ameliorates schistosomiasis liver granuloma in mice by suppressing male and female reproductive systems and egg development of Schistosoma japonicum

Schistosomiasis is a serious and widespread parasitic disease caused by infection with Schistosoma. Because the parasite’s eggs are primarily responsible for schistosomiasis dissemination and pathogenesis, inhibiting egg production is a potential approach to control the spread and severity of the disease. The bromodomain and extra-terminal (BET) proteins represent promising targets for the development of epigenetic drugs against Schistosoma. JQ-1 is a selective inhibitor of the BET protein family. In the present study, JQ-1 was applied to S. japonicum in vitro. By using laser confocal scanning microscopy and EdU incorporation assays, we showed that application of JQ-1 to worms in vitro affected egg laying and the development of both the male and female reproductive systems. JQ-1 also inhibited the expression of the reproductive-related genes SjPlk1 and SjNanos1 in S. japonicum. Mice infected with S. japonicum were treated with JQ-1 during egg granuloma formation. JQ-1 treatment significantly reduced the size of the liver granulomas and levels of serum alanine aminotransferase and aspartate aminotransferase in mice and suppressed both egg laying and the development of male and female S. japonicum reproductive systems in vivo. Moreover, the mRNA expression levels of some proinflammatory cytokines were decreased in the parasites. Our findings suggest that JQ-1 treatment attenuates S. japonicum egg–induced hepatic granuloma due at least in part to suppressing the development of the reproductive system and egg production of S. japonicum. These findings further suggest that JQ-1 or other BET inhibitors warrant additional study as a new approach for the treatment or prevention of schistosomiasis.     

皮层神经发生的分子调控机制

在高等动物神经发育过程中,背侧端脑神经上皮细胞在多种调控基因及环境调控因子的作用下经历了错综复杂的发育事件,逐步形成具有精细的分层结构和高级功能的神经皮层。这些发育中的调控具有严格的时间和区域特性。本文主要就皮层形成中神经干细胞增殖、分化方向及皮层神经元亚型的特化等方面的调控机制予以论述。