Ultrastructural studies of endocrine-like cells in the fundic gastric mucosa of the bullfrog,Rana catesbeiana

Summary This study is concerned with electron-microscopic observations on endocrine or paracrine cells in the fundic gastric mucosa of the bullfrog. Also, an attempt was made to identify the histamine-releasing cells involved in the secretagogue response. At least three distinct endocrine-like cell types were found. The classification is based on the appearance of secretory granules and other organelles, and the relationship of endocrine-like cells with other cells in the tissue. The amphibian endocrine-like cells resemble the ECL, D and EC cells of mammals. Type-I (ECL) cells showed degranulation after repeated stimulation with tetragastrin (TG), acetylcholine (ACh) and K⁺ depolarizing solution, all of which release histamine.     

Coexistence of cytoplasmic and nuclear genes for male sterility in Petunia

Summary Cytoplasmic male sterility (cms) and nuclear male sterility (nms) in Petunia were described respectively as possible autonomous and integrated states of the same genetic element by Frankel (1971). In the present study we describe genetic analysis of the interaction between the cms, the nuclear gene for male sterility (e) and the fertility restorer allele (Rf). The main findings in this study are: (1) The nuclear sterility allele can coexist in one or two dosages with the cytoplasmic male sterility elements (ste) in somatic cells or female gametes; (2) the presence of the fertility restorer allele Rf is not required for the coexistence of ste and e and (3) Rf does not interact epistatically with e, e.g., the expression of e is independent of Rf—the genotypes (S) RfRfee and (S) Rfrfee are male sterile.Contribution from the Agricultural Research Organization. The Volcani Center, Bet Dagan, Israel. 1983 series No. 846 E     

A high-fat diet rich in corn oil exaggerates the infarct size and memory impairment in rats with cerebral ischemia and is associated with suppressing osteopontin and Akt,and activating GS3Kβ, iNOS,and NF-κB

Journal of Physiology and Biochemistry - The increase in osteopontin (OPN) levels after stroke induces neural protection by activating Akt signaling and inhibiting GS3Kβ, iNOS, and NF-κB....     

Trichinella spiralis: strong antibody response to a 49 kDa newborn larva antigen in infected rats

In this work, we analyzed the kinetics of anti-Trichinella spiralis newborn larva (NBL) antibodies (Ab) and the antigenic recognition pattern of NBL proteins and its dose effects. Wistar rats were infected with 0, 700, 2000, 4000 and 8000 muscle larvae (ML) and bled at different time intervals up to day 31 post infection (p.i.). Ab production was higher with 2000 ML dose and decreased with 8000, 4000 and 700 ML. Abs were not detected until day 10, peaked on day 14 for the 2000 ML dose and on day 19 for the other doses and thereafter declined slowly from 19 to 31 days p.i. In contrast, Abs to ML increased from day 10, peaked on day 19 and remained high until the end of the study. Abs bound strongly at least to three NBL components of 188, 205 and 49 kDa. NBL antigen of 188 and 205 kDa were recognized 10-26 days p.i. and that of 49 kDa from day 10 to day 31 p.i. A weak recognition towards antigens of 52, 54, 62 and 83 kDa was also observed during the infection. An early recognition of 31, 43, 45, 55, 68 and 85 kDa ML antigens was observed whereas the response to those of 43, 45, 48, 60, 64 and 97 kDa (described previously as TSL-1 antigens) occurred late in the infection. A follow-up of antigen recognition up to day 61 with the optimal immunization dose (2000 ML) evidenced a decline of Ab production to the 49 kDa NBL antigen 42 days p.i., which suggested antigenic differences with the previously reported 43 kDa ML antigen strongly recognized late in the infection. To analyze the stage-specificity of the 49 kDa NBL antigen, polyclonal antibodies (PoAb) were obtained in rats immunized with 49 kDa NBL antigen. PoAb reacted strongly with the 49 kDa NBL component in NBL total soluble extract but no reactivity was observed with soluble antigen of the other T. spiralis stages. Albeit with less intensity, the 49 kDa component was also recognized by PoAb together with other antigens of 53, 97 and 107 kDa, in NBL excretory-secretory products (NBL-ESP). Thus, our results reveal differences in the kinetics of anti-NBL and ML Ab responses. While anti-NBL Abs declined slowly from day 19 until the end of the experiment, Abs to ML antigen remained high in the same period. It is remarkable the optimal Ab response to NBL antigens with 2000 ML infective dose and the reduced number of NBL antigens identified throughout the experimental T. spiralis infection, standing out the immunodominant 49 kDa antigen. Interestingly, this antigen, which was prominently expressed in NBL somatic proteins, was also detected in NBL-ESP.     

Time-resolved fluorescence of 2-aminopurine as a probe of base flipping in M.HhaI-DNA complexes

DNA base flipping is an important mechanism in molecular enzymology, but its study is limited by the lack of an accessible and reliable diagnostic technique. A series of crystalline complexes of a DNA methyltransferase, M.HhaI, and its cognate DNA, in which a fluorescent nucleobase analogue, 2-aminopurine (AP), occupies defined positions with respect the target flipped base, have been prepared and their structures determined at higher than 2 Å resolution. From time-resolved fluorescence measurements of these single crystals, we have established that the fluorescence decay function of AP shows a pronounced, characteristic response to base flipping: the loss of the very short (~100 ps) decay component and the large increase in the amplitude of the long (~10 ns) component. When AP is positioned at sites other than the target site, this response is not seen. Most significantly, we have shown that the same clear response is apparent when M.HhaI complexes with DNA in solution, giving an unambiguous signal of base flipping. Analysis of the AP fluorescence decay function reveals conformational heterogeneity in the DNA–enzyme complexes that cannot be discerned from the present X-ray structures.     

The relA homolog of Mycobacterium smegmatis affects cell appearance, viability, and gene expression

The modification of metabolic pathways to allow for a dormant lifestyle appears to be an important feature for the survival of pathogenic bacteria within their host. One regulatory mechanism for persistent Mycobacterium tuberculosis infections is the stringent response. In this study, we analyze the stringent response of a nonpathogenic, saprophytic mycobacterial species, Mycobacterium smegmatis. The use of M. smegmatis as a tool for studying the mycobacterial stringent response was demonstrated by measuring the expression of two M. tuberculosis genes, hspX and eis, in M. smegmatis in the presence and absence of rel(Msm). The stringent response plays a role in M. smegmatis cellular and colony formation that is suggestive of changes in the bacterial cell wall structure.     

The identification of the acid-base catalyst of alpha-arabinofuranosidase from Geobacillus stearothermophilus T-6, a family 51 glycoside hydrolase

The alpha-L-arabinofuranosidase from Geobacillus stearothermophilus T-6 (AbfA T-6) belongs to the retaining family 51 glycoside hydrolases. The conserved Glu175 was proposed to be the acid-base catalytic residue. AbfA T-6 exhibits residual activity towards aryl beta-D-xylopyranosides. This phenomenon was used to examine the catalytic properties of the putative acid-base mutant E175A. Data from kinetic experiments, pH profiles, azide rescue, and the identification of the xylopyranosyl azide product provide firm support to the assignment of Glu175 as the acid-base catalyst of AbfA T-6.     

Erratum to: Synthesis and Anticancer Activity of Functionalized Thieno[2,3-d]pyrimidine Compounds and Their Triazinyl and Tetrazinyl Derivatives

Russian Journal of Bioorganic Chemistry - erratum     

Daily profile in ghrelin and hypothalamic ghrelin receptors in obese and lean mice Neotomodon alstoni

Mice Neotomodon alstoni develops, in some individuals, overweight and obesity when kept in vivarium conditions and fed on standard rodent diet. In the present study, we explored the possible differences between lean and obese mice, on the daily expression of the hormone ghrelin, its total and active form, as well as the relative expression of ghrelin receptors (GSHR) in hypothalamic tissue. Plasma hormones were detected and quantified by immunological techniques by ELISA; the relative presence of GSHR was assessed by western blot. Mice were sacrificed at different times throughout the day. The results obtained indicate that there is a rhythm of presence of total and acylated ghrelin in lean mice, which dampers and changes its peak’s phase in obese mice. The GHSR expression tend to be more abundant in obese mice than in lean mice. The results indicate that, in the obese mice there is a possible resistance to ghrelin.