Effects of stress on endocrine and metabolic processes and redirection: cross talk between subcellular compartments

Recent advances in genome analysis and biochemical pathway mapping have advanced our understanding of how biological systems have evolved over time. Protein and DNA marker comparisons suggest that several of these systems are both ancient in origin but highly conserved into today's evolved species. However, remnants of some of the more ancient functions of these chemical systems can run in conflict with the functions that those same pathways serve in complex organisms and tissue systems today. Relevant to the present topic, nitric oxide (NO) and superoxide anion (O₂^•−), ancient cellular molecules in evolutionary terms, are recognized today as both necessary for the well-being and stable health of cells but also injurious to cells as elaborated in conjunction with the cellular stress response. Why the dichotomy? This question underlies one of the basic issues challenging researchers as well as practitioners in their approach to disease management. The fundamental proinflammatory response of the innate immune system of the host is needed for pathogen control but can be injurious to tissues from “collateral damage” from NO- and O₂^•−-derived reactive molecules capable of affecting protein function via post-translational chemical modification. This review highlights newer aspects of the biochemistry of the NO- and O₂^•−-mediated innate proinflammatory response and further show how protein and tissue damage via overproduction of reactive nitrogen and oxygen intermediary molecules such as peroxynitrite (ONOO⁻) might be targeted to specific epitopes of proteins. Changes in the regulation of metabolism in response to proinflammatory disease states are discussed for GH signal transduction and tissue specificity.     

云勇生态林空气负离子浓度及变化规律

文章于2009年9月对广东省佛山市云勇生态林养护中心林地9个地点不同林分的空气负离子浓度进行了实地观测,分析了其变化规律,并于2011年12月观测了其中三种林分距离地面不同高度处的空气负离子含量及空气温湿度,分析了空气负离子含量与空气温湿度的相关性。结果如下:(1)9个不同地点林分的空气负离子浓度介于550～2 150个/cm3之间,不同林分空气负离子浓度差异显著;(2)一天中不同时刻、不同林分的空气负离子浓度不同,且不同林分的空气负离子波峰值出现的时刻不同;(3)负离子浓度随着高度的上升而显著减小,不同高度处空气质量评价指标CI值的差异不显著;(4)在近地面0.5 m处空气负离子浓度和空气质量评价指标CI值均与温度呈负相关,与相对湿度呈正相关。     

植物根细胞离子通道研究进展

根细胞膜上存在各种离子通道.电生理学的研究表明,根细胞离子通道对于矿质吸收、转运及植物耐盐具有重要作用.该文概述了根细胞K+通道、阴离子通道和各种非选择性阳离子通道的最新研究进展,并对近期有关离子通道和植物耐盐性关系的研究进行了总结.K+通道存在于大多数的植物细胞中,其对K+的选择性远高于其他阳离子,K+通道的存在对于营养元素的吸收,尤其是K+的低亲和性吸收具有重要的意义,同时也为其他离子的出入维持了一个较为稳定的膜电势.阴离子通道激活所引起的质膜去极化可以激发非选择性的阳离子流,在盐胁迫下,可通透Cl的阴离子通道的开放是植物对胞内Cl的一种重要调控机制.由于非选择性的阳离子通道(Non-selective cation channels,NSCCs)的多样性及其对一价阳离子的低选择性,近年来NSCCs的研究受到广泛关注.NSCCs被认为参与了植物多种生理过程,包括营养元素的吸收、膨压控制、胞间转运、信号转导以及毒害离子的吸收,尤其是Na+的吸收.      

蒲公英抗氧化活性部位研究

为研究蒲公英抗氧化成分的分布,采用传统水提法提取蒲公英中的有效成分,并依次用石油醚、乙酸乙酯和正丁醇萃取,然后用FRAP法、超氧阴离子清除率法和DPPH法研究各层提取物的体外抗氧化活性。结果表明,各层提取物均具有体外抗氧化活性,三种不同测试方法显示其抗氧化能力大小均为:正丁醇层乙酸乙酯层水层石油醚层。说明蒲公英中抗氧化活性最强的是正丁醇层和乙酸乙酯层中。     

Effect of Pichia membranaefaciens on ROS metabolism and postharvest disease control in citrus fruit

The yeast Pichia membranaefaciens has antagonistic effects against a wide range of phytopathogenic fungi that cause postharvest fruit decay. This work evaluated the effects of P. membranaefaciens on the reactive oxygen species (ROS) metabolism and disease control in harvested citrus fruit (Citrus sinensis L. Osbeck). The lesion diameter caused by Penicillium italicum and Penicillium digitatum on citrus fruit was remarkably reduced when the fruit was point-inoculated or dipped in a suspension of P. membranaefaciens at 1 × 10⁸ CFU mL⁻¹. The application of P. membranaefaciens on citrus fruit enhanced the activity of superoxide dismutase, ascorbate peroxidase, and glutathione reductase, as well as the levels of hydrogen peroxide, the superoxide anion and glutathione, but inhibited the decreasing ascorbic acid content. Furthermore, catalase activity was decreased by the same treatment. These results indicated that yeast treatment induced the synthesis of antioxidant enzymes which might have antagonistic effects against postharvest green and blue mold infection in citrus fruit.     

Anti-Inflammatory Cembranoids from a Formosa Soft Coral Sarcophyton cherbonnieri

The present investigation on chemical constituents of the soft coral Sarcophyton cherbonnieri resulted in the isolation of seven new cembranoids, cherbonolides F–L (1–7). The chemical structures of 1–7 were determined by spectroscopic methods, including infrared, one- and two-dimensional (1D and 2D) NMR (COSY, HSQC, HMBC, and NOESY), MS experiments, and a chemical reduction of hydroperoxide by triphenylphosphine. The anti-inflammatory activities of 1–7 against neutrophil proinflammatory responses were evaluated by measuring their inhibitory ability toward N-formyl-methionyl-leucyl-phenylalanine/cytochalasin B (fMLF/CB)-induced superoxide anion generation and elastase release in primary human neutrophils. The results showed that all isolates exhibited moderate activities, while cherbonolide G (2) and cherbonolide H (3) displayed a more active effect than others on the inhibition of elastase release (48.2% ± 6.2%) and superoxide anion generation (44.5% ± 4.6%) at 30 µM, respectively.     

Dietary cation and anion difference: Effects on milk production and body fluid distribution in lactating dairy goats under tropical conditions

This study aimed to determine the effect of dietary cation and anion difference (DCAD) on milk production and body fluid distribution in lactating dairy goats. Ten dairy goats were selected and divided into two groups, five animals each. Animals received either control DCAD (control, 22.81 mEq/100 g dry matter (DM)) or high DCAD (DCAD, 39.08 mEq/100 g DM). The results indicated that rectal temperature (Tr), respiration rate, milk yield and compositions did not differ between groups. But the percentage change of Tr from the DCAD group was lower than the control group between 09.00 and 13.00 hours. DM intake tended to increase in the DCAD group. Dairy goats in the DCAD group drank more water, but urinary excretion and plasma antidiuretic hormone concentration remained unchanged. Apparent water balance was higher from the DCAD group over 24 h. There was no effect of DCAD on plasma and blood volumes, but tended to increase in extracellular fluid and thereby increased total body water. The present results indicate that animals supplemented with high DCAD increase their total body water and apparent water balance. These results have contributed to the process of adaptation for evaporative cooling and would be useful in slowing down the elevation in Tr.     

Pinnisterols A–C,New 9,11-Secosterols from a Gorgonian Pinnigorgia sp.

Three new 9,11-secosterols, pinnisterols A–C (1–3), were isolated from a gorgonian coral Pinnigorgia sp., collected off the waters of Taiwan. The structures of these compounds were elucidated on the basis of spectroscopic methods. The new sterols 1 and 3 displayed significant inhibitory effects on the generation of superoxide anions and the release of elastase by human neutrophils, and sterol 1 was found to show moderate cytotoxicity in hepatic stellate cells (HSCs).     

Overproduction of reactive oxygen species involved in the pathogenicity of Fusarium in potato tubers

Differences in virulence between Fusarium sulphureum and Fusarium sambucinum were compared. Changes in reactive oxygen species production and metabolism in inoculated slices of potato tubers were also compared. The result showed that Fusarium infection induced significant production of ROS, lipid peroxidation and loss of cell membrane integrity, but low activity of superoxide dismutase (SOD) and ascorbate peroxidase (APX). Compared to F. sambucinum, F. sulphureum led larger lesion diameters on potato tubers and slices. It resulted in more superoxide anion ($O_2^{-}$) and earlier peak of hydrogen peroxide (H₂O₂), but lower activity of catalase (CAT) and APX, and accompanied with higher malondialdehyde (MDA) content and lower cell membrane integrity. These findings suggested that overproduction of ROS involved in the pathogenicity of Fusarium in potato tubers.     

Uranium recovery from leach solution in in situ leaching of uranium with ion exchange absorption

The absorption of uranium by ion exchange resin is studied based on the characters of pregnant solution for a new uranium in situ leaching mine. The resin types, the absorption parameters and the eluting parameters are chosen in the experiments. The results showd that the 201×7 strong alkaline anion exchange resin and TSF 2 anion exchange resin had good absorption and eluting effects. The fixed bed anion exchange absorption is a suitable technology and NH4NO3＋HNO3 mixed solution is an appropriate eluting reagent for this technology.