Intrinsic vs. extrinsic influences on life history expression: metabolism and parentally induced temperature influences on embryo development rate

Intrinsic processes are assumed to underlie life history expression and trade‐offs, but extrinsic inputs are theorised to shift trait expression and mask trade‐offs within species. Here, we explore application of this theory across species. We do this based on parentally induced embryo temperature as an extrinsic input, and mass‐specific embryo metabolism as an intrinsic process, underlying embryonic development rate. We found that embryonic metabolism followed intrinsic allometry rules among 49 songbird species from temperate and tropical sites. Extrinsic inputs via parentally induced temperatures explained the majority of variation in development rates and masked a relationship with metabolism; metabolism explained a minor proportion of the variation in development rates among species, and only after accounting for temperature effects. We discuss evidence that temperature further obscures the expected interspecific trade‐off between development rate and offspring quality. These results demonstrate the importance of considering extrinsic inputs to trait expression and trade‐offs across species.     

分泌型磷脂酶PLA2G5的生物学功能及其抑制剂研究进展

分泌型磷脂酶PLA2G5属于磷脂酶A2超家族的一员,在免疫细胞和非免疫细胞中均有表达.研究表明,PLA2G5参与生物学事件的发生发展,在特定的病理条件下具有诱导作用.本文简要阐述了PLA2G5的来源、结构特征、生物学功能和在疾病中的作用,以及现有或潜在的PLA2G5抑制剂,以期探索基于PLA2G5的治疗新靶标.     

In-depth Profiling and Quantification of the Lysine Acetylome in Hepatocellular Carcinoma with a Trapped Ion Mobility Mass Spectrometer

Hepatocellular carcinoma (HCC) is the third most common cause of cancer-related death worldwide with limited therapeutic options. Comprehensive investigation of protein posttranslational modifications in HCC is still limited. Lysine acetylation is one of the most common types of posttranslational modification involved in many cellular processes and plays crucial roles in the regulation of cancer. In this study, we analyzed the proteome and K-acetylome in eight pairs of HCC tumors and normal adjacent tissues using a timsTOF Pro instrument. As a result, we identified 9219 K-acetylation sites in 2625 proteins, of which 1003 sites exhibited differential acetylation levels between tumors and normal adjacent tissues. Interestingly, many novel tumor-specific K-acetylation sites were characterized, for example, filamin A (K865), filamin B (K697), and cofilin (K19), suggesting altered activities of these cytoskeleton-modulating molecules, which may contribute to tumor metastasis. In addition, we observed an overall suppression of protein K-acetylation in HCC tumors, especially for enzymes from various metabolic pathways, for example, glycolysis, tricarboxylic acid cycle, and fatty acid metabolism. Moreover, the expression of deacetylase sirtuin 2 (SIRT2) was upregulated in HCC tumors, and its role of deacetylation in HCC cells was further explored by examining the impact of SIRT2 overexpression on the proteome and K-acetylome in Huh7 HCC cells. SIRT2 overexpression reduced K-acetylation of proteins involved in a wide range of cellular processes, including energy metabolism. Furthermore, cellular assays showed that overexpression of SIRT2 in HCC cells inhibited both glycolysis and oxidative phosphorylation. Taken together, our findings provide valuable information to better understand the roles of K-acetylation in HCC and to treat this disease by correcting the aberrant acetylation patterns.     

Effect of Vaccinium ashei reade Leaf Extracts on Lipid Metabolism in Obese OLETF Rats

The effects of a hot water extract and fractional extracts from rabbiteye blueberry (Vaccinium ashei reade) leaves (BBL) on lipid metabolism were studied in obese Otsuka Long-Evans Tokushima Fatty (OLETF) rats. Feeding the hot water extract and fractional extracts from BBL alleviated hepatic triglyceride accumulation in the rats. Additionally, feeding with the flavonol glycoside (FG) and proanthocyanidin (PA) fractions lowered serum cholesterol levels in the obese rats. The results from measurements of the hepatic enzyme activity indicate that the hypolipidemic effects of the hot water extract and the PA fraction might be attributable to enhanced lipolysis in the liver. The reduced serum levels of C-reactive protein, an inflammatory cytokine, by the chlorogenic acid + rutin fraction and FG fraction might be associated with alleviating the metabolic abnormalities in obese rats. These results indicate that the BBL extracts, and especially FG and PA, exerted hypolipidemic effects on obese OLETF rats and suggest that an infusion of BBL can be useful as a dietary hypolipidemic component.     

Up- and down-regulation of membrane receptors as possible mechanisms related to the antiulcer actions of milk in rat gastric mucosa

The effects of a cow's milk diet on receptor activity and histamine metabolism in gastric glands and mucosa isolated from adult rats were examined. The milk diet was associated with (1) a decreased mobilization of H₂ receptors by histamine and (2) an increased mobilization of PGE₂ (prostaglandin E₂) receptors in mucous cells (cytoprotective effect) and parietal cells (antiacid effect). These changes are not observed for the receptors reducing pentagastrin- and histamine-induced gastric acid secretion (pancreatic/enteroglucagons, somatostatin) and stimulating mucus, bicarbonate and pepsin secretions in the rat (secretin). Cimetidine produced a parallel displacement of the histamine dose-response curve, suggesting competitive inhibition between this classical H₂ receptor antagonist and histamine in the two experimental groups. Prostaglandins and other components in milk such as EGF (epidermal growth factor) and somatostatin might therefore protect gastric mucosa by a differential control of PGE₂ and histamine H₂ receptor activity eitherdirectly (PGE₂ in milk) orindirectly (inhibition of endogeneous histamine synthesis/release and stimulation of PGE-I synthesis/release).     

C-NMR analysis of Aspergillus mutants disturbed in pyruvate metabolism

The metabolic consequences of two defects in pyruvate metabolism of the hyphal fungus Aspergillus nidulans have been investigated by natural abundance ¹³C-NMR spectroscopy. A pyruvate dehydrogenase complex (pdh) mutant, grown on acetate, accumulates alanine upon starvation which is derived from mannitol reserves. The -alanine level increases further upon incubation with the non-permissive substrate -glucose. -Glutamate is absent from these spectra as it is required both for the transamination of pyruvate and as a reaction on an impaired energy metabolism in such a pdh-deficient strain. A pyruvate carboxylase (pyc) mutant, grown upon acetate, only starts to accumulate alanine after a long incubation period with -glucose, due to the long-lasting presence of phosphoenolpyruvate carboxykinase and malic enzyme, which are both induced by growth on acetate. When this strain is grown on -fructose and -glutamate, alanine also accumulates within 3 h upon transfer to -glucose.     

Cytokinin metabolism in tomato plants. II. Metabolites of kinetin and benzyladenine in decapitated roots

Decapitated tomato plants were supplied via the roots with [8-¹⁴C]-kinetin or [8-¹⁴C]-benzyladenine in a nutrient solution for a period of 24 h. After this time the root material, the root sap produced during the 24 h period and the nutrient solution remaining at the end of the experiments were analysed for cytokinins. HPLC techniques and chemical treatments were used to tentatively identify radioactive metabolites formed. Uptake of kinetin and benzyladenine by the roots was found to be limited but once within the root tissues metabolism was both rapid and extensive.At least 14 metabolites of kinetin were recovered from root tissue and root sap. Many of these appeared to be degradation products. There was, however, some evidence of formation of zeatin-like derivatives. Side-chain cleavage of the original kinetin which occurs rapidly is suggested as a possible route for the eventual production of these endogenous cytokinin forms.The benzyladenine taken up by the roots was apparently both ribosylated and glucosylated. No unmetabolized benzyladenine was detected in the root tissues after 24 h. Only very low levels of radioactivity were associated with the retention time of adenine, suggesting that in the case of benzyladenine side-chain cleavage is of limited importance.The significance of these reactions in relation to the potential use of cytokinins in the regulation of plant growth is discussed.     

Endogenous opiates: 1986

This is the ninth installment of our annual review of research involving the endogenous opiate peptides. It is restricted to the non-analgesic and behavioral studies of the opiate peptides published in 1986. The specific topics this year include stress; tolerance and dependence; eating; drinking; gastrointestinal, renal, and hepatic processes; mental illness; learning, memory, and reward; cardiovascular responses; respiration and thermoregulation; seizures and other neurological disorders; activity; sex, pregnancy, and development; and some other behaviors.