Endogenous oscillatory activity and TTX-sensitive spikes of the heart muscle in early juveniles of the isopod crustaceanLigia exotica

The heart beat of early juveniles of the littoral isopodLigia exotica occurred at a frequency of 250 to 350/min, associated with rhythmic activity of the heart muscle. Each burst was composed of a slow depolarizing potential with superimposed spike potentials. The spike potential was eliminated by perfusion with TTX-containing or Na⁺-free saline. In TTX-saline, the slow potential was unchanged in frequency and amplitude. By current injection into the heart muscle, the rhythm of the slow potential was phase-shifted and its frequency was changed in a membrane potential-dependent manner. These results show that the heart ofLigia early juveniles acts as an endogenous muscle oscillator generating oscillatory slow potentials and Na⁺-dependent spikes.     

Antioxidant survey to assess antagonism to redox stress using a prokaryotic and an eukaryotic system

Using a prokaryote (Escherichia coli) and a metazoa-resembling eukaryote (Ochromonas danica), we surveyed antioxidants which might overcome redox stress imposed by menadione sodium bisulphite (MD) and buthionine sulphoximine (BSO). BSO oxidant stress was evident only inO. danica; MD oxidant stress was evident in both organisms. Glutathione, its precursors, e.g. cysteine, homocysteine, and 2-oxo-4-thiazolidine carboxylic acid, and red blood cells, emerged as prime antioxidants for relieving BSO and MD oxidant stress. BSO and MD oxidant activity and antioxidant-annulling effect inO. danica were judged comparable to those found in animal cells whereas the resultsE. coli were not entirely equivalent. TheO. danica system emerged as a practical, rapid, and useful system for pinpointing oxidant stressors and antioxidants, and shows promise for studies with mammalian systems.     

(−)-Epigallocatechin gallate,a polyphenolic tea antioxidant,inhibits peroxynitritemediated formation of 8-oxodeoxyguanosine and 3-nitrotyrosine

Reaction with peroxynitrite at pH 7.4 and 37°C was found to increase the 8-oxodeoxyguanosine levels in calf thymus DNA 35-38-fold. This oxidation of deoxyguanosine, as well as the peroxynitrite-mediated nitration of tyrosine to 3-nitrotyrosine, was significantly inhibited by ascorbic acid, glutathione and (–)-epigallocatechin gallate, a polyphenolic antioxidant present in tea. For 50% inhibition of the oxidation of deoxyguanosine to 8-oxodeoxyguanosine, 1.1, 7.6 of 0.25 mM ascorbate, glutathione or (–)-epigallocatechin gallate, respectively, was required. For 50% inhibition of tyrosine nitration, the respective concentrations were 1.4, 4.6 or 0.11 mM. Thus, (–)-epigallocatechin gallate is a significantly better inhibitor of both reactions than either ascorbate or glutathione. Reaction of (–)-epigallocatechin gallate with peroxynitrite alone resulted in the formation of a number of products. Ultraviolet spectra of two of these suggest that the tea polyphenol and/or its oxidation products are nitrated by peroxynitrite.     

Butterflies and ants: The communicative domain

Associations with ants, termed myrmecophily, are widespread in the butterfly family Lycaenidae and range from mere co-existence to more or less specific mutualistic or even parasitic interactions. Secretions of specialized epidermal glands are crucial for mediating the interactions. Transfer of nutrients (carbohydrates, amino acids) from butterfly larvae to ants plays a major role, but manipulative communication with the help of odour signals is also involved. By means of myrmecophily, lycaenid butterflies largely escape ant predation, and certain species gain protection through attendant ants or achieve developmental benefits from ant-attendance. Benefits to the ants range from minimal to substantial food rewards. While most lycaenid species maintain facultative relationships with a variety of ant genera, highly specific and obligatory associations have convergently evolved in a number of butterfly lineages. As a corollary, communication systems are largely unspecific in the former, but may be highly specialized in the latter. The sophisticated communication between obligate myrmecophiles and their host ants is tightly connected with the evolutionary rise of specialized life-cycles and thus is a source of augmenting diversity within the butterflies.     

Concept of an extracellular regulation of muscular metabolic rate during heavy exercise in humans by psychophysiological feedback

Efferent motor signals to skeletal muscles concern not only the space/time pattern of motion, but also the setting of muscular performance and through this the control of the current metabolic rate. For an optimal adjustment of metabolic rate during heavy exercise — e.g. in athletic competitions — a feedback control system must exist, including a programmer that takes into consideration a finishing point (teleoanticipation). The presented experiments, using Borg's scale, indicate the existence and functioning of a system for optimal adjustment of performance during heavy exercise and the relevance of teleoanticipatory effects. Thus motor learning includes not only somatosensory control, but also metabolic control. With regard to migratory birds, such metabolic control would have to operate in the individual as well as in the migrating flock as a whole.     

KineticsandMechanismStudiesontheInteractionofTetramethoxylbenzoquinonewithPiperidines

ＫｉｎｅｔｉｃｓａｎｄＭｅｃｈａｎｉｓｍＳｔｕｄｉｅｓｏｎｔｈｅＩｎｔｅｒａｃｔｉｏｎｏｆＴｅｔｒａｍｅｔｈｏｘｙｌｂｅｎｚｏｑｕｉｎｏｎｅｗｉｔｈＰｉｐｅｒｉｄｉｎｅｓ＊ＬｉＺｈａｏｌｏｎｇ（李兆陇），ＦｕＨｕａ（付华），ＰｅｎｇＳｈｕｗｅｎ（彭树...     

论亚当·斯密市场经济概念中的道德观

Adam Smith是美国经济学的创始人。他在《国富论》中强调了市场中“看不见的手”的力量。在《道德情操论》中,论述了道德的力量。本文将两部著作的思想连贯起来,分析道德观念对市场经济中人们行为的影响。     

论“武王伐纣”战役中的巴、蜀之师

约公元前1066年的西方周族，在经过先前周文王的苦心经营后，由一个蕞尔小邦发展成拥有数十万大军的强国，为灭殷帝国打下了坚实的基础。武王继位，在孟津观兵之后二年，这时期的周族已在政治上，军事上都取得了能与殷帝国抗衡的优势后，从而发动了我国历史上著名的“牧野之战”（即“武王伐纣”之战）。当时跟随周方参战中的巴、蜀二国不仅参战人数众，而且还是周方作战的先头部队，在大决战的关键时刻，巴蜀之师以威武。勇猛之气势压到了对方。     

浅谈电子信息资源的合法利用

网络时代，电子信息资源已成为人们进行科学研究、商业活动和共享信息的重要手段，与此同时，网上侵权行为也时有发生。指出了电子信息资源的侵权形式，探讨了在版权法允许的范围内合法利用电子信息资源的有关问题。     

高校图书馆知识管理浅谈

知识管理是知识经济时代的一种全新的管理思想。阐述了高校图书馆在对自身实施知识管理时应注意的环节、存在的问题以及所要避免陷入的几个误区，并对未来的知识管理进行了展望。