The Problem of Recovery of Physiological Functions in Humans in Deep Accidental Hypothermia (to the Problem of Limits of Physiological Adaptation)

At present, the recovery of physiological functions in a cooled man after different kinds of accidents and sea catastrophes (accidental hypothermia) is a topical task of emergency medicine and, at the same time, an important problem of thermobiology, thermoregulation, and bioenergetics. This work outlines the disturbances of the physiological functions of the body at different stages of the development of accidental hypothermia, the main modern methods of recovery of these functions, and some unresolved problems of the physiology of resuscitating hypothermia victims. New achievements in the study of the mechanisms of cold-induced disorders of physiological functions are presented in this work, and the correction of the physiological methods for restoring the life activity of a cooled man is proposed.     

Novel Insights into the Enzymology,Regulation and Physiological Functions of Light-dependent Protochlorophyllide Oxidoreductase in Angiosperms

The reduction of protochlorophyllide (Pchlide) is a key regulatory step in the biosynthesis of chlorophyll in phototrophic organisms. Two distinct enzymes catalyze this reduction; a light-dependent NADPH:protochlorophyllide oxidoreductase (POR) and light-independent Pchlide reductase (DPOR). Both enzymes are widely distributed among phototrophic organisms with the exception that only POR is found in angiosperms and only DPOR in anoxygenic photosynthetic bacteria. Consequently, angiosperms become etiolated in the absence of light, since the reduction of Pchlide in angiosperms is solely dependent on POR. In eukaryotic phototrophs, POR is a nuclear-encoded single polypeptide and post-translationally imported into plastids. POR possesses unique features, its light-dependent catalytic activity, accumulation in plastids of dark-grown angiosperms (etioplasts) via binding to its substrate, Pchlide, and cofactor, NADPH, resulting in the formation of prolamellar bodies (PLBs), and rapid degradation after catalysis under subsequent illumination. During the last decade, considerable progress has been made in the study of the gene organization, catalytic mechanism, membrane association, regulation of the gene expression, and physiological function of POR. In this review, we provide a brief overview of DPOR and then summarize the current state of knowledge on the biochemistry and molecular biology of POR mainly in angiosperms. The physiological and evolutional implications of POR are also discussed.     

生物表面活性剂对微生物生长和代谢的影响

综述了生物表面活性剂在微生物生长和代谢过程中的影响。根据其分子结构特征 ,系统分析了生物表面活性剂通过与难溶底物和微生物细胞之间的相互作用促进烷烃摄取的机理 ,利用该机理可以合理解释生理现象。生物表面活性剂还在参与细胞代谢活动的过程中发挥特殊功能。     

Intermittent Normobaric Hypoxia as a Model of Incomplete Adaptation

The Neirokartograf software was used to calculate the correlations between EEG, external respiration, and gas exchange parameters recorded in the initial state, after 10 or 20 sessions of intermittent normobaric hypoxia (INH), and after its cessation. It was demonstrated that cerebral structures were increasingly involved in gas exchange control in ascending order during the course of INH sessions. The artificial short-term extreme exposure followed by a return to usual conditions resulted in incomplete adaptation. Even 20 days after the cessation of INH sessions, neurodynamics did not return to the initial state.     

细菌中糖转运相关sRNA 的生理调控功能

当细菌面对较高浓度的葡萄糖时,随着葡萄糖摄入,常会导致菌体内部葡糖-6-磷酸的大量累积。在磷酸糖浓度达到一定阈值时,就会形成一种毒性胁迫从而抑制菌体的代谢与生长。许多细菌则会通过一种小RNA SgrS (sugar transport-related sRNA)的转录后调控作用,来解除这种糖胁迫抑制作用。SgrS在分子伴侣Hfq的协助下,与相应靶mRNA通过碱基互补配对方式结合,对ptsG mRNA和manXYZ mRNA进行负调控以减少糖类摄入,并对yigL mRNA进行正调控以增大糖类排出,从而提高细胞对糖胁迫的耐受性。与一般sRNA不同,SgrS作为一种双功能sRNA,除具有转录后调控功能外,还能够翻译出蛋白质SgrT。SgrS广泛存在于肠杆菌中,但不同菌属中SgrS的差异极大。本文主要对SgrS在细菌中的功能、分布及其差异进行综述。     

Physiological Functions of the COPI Complex in Higher Plants

COPI vesicles are essential to the retrograde transport of proteins in the early secretory pathway. The COPI coatomer complex consists of seven subunits, termed α-, β-, β′-, γ-, δ-, ε-, and ζ-COP, in yeast and mammals. Plant genomes have homologs of these subunits, but the essentiality of their cellular functions has hampered the functional characterization of the subunit genes in plants. Here we have employed virus-induced gene silencing (VIGS) and dexamethasone (DEX)-inducible RNAi of the COPI subunit genes to study the in vivo functions of the COPI coatomer complex in plants. The β′-, γ-, and δ-COP subunits localized to the Golgi as GFP-fusion proteins and interacted with each other in the Golgi. Silencing of β′-, γ-, and δ-COP by VIGS resulted in growth arrest and acute plant death in Nicotiana benthamiana, with the affected leaf cells exhibiting morphological markers of programmed cell death. Depletion of the COPI subunits resulted in disruption of the Golgi structure and accumulation of autolysosome-like structures in earlier stages of gene silencing. In tobacco BY-2 cells, DEX-inducible RNAi of β′-COP caused aberrant cell plate formation during cytokinesis. Collectively, these results suggest that COPI vesicles are essential to plant growth and survival by maintaining the Golgi apparatus and modulating cell plate formation.     

Regulation and Control of Multiple Pathways of Respiratory Metabolism in Relation to Other Physiological Functions in Higher Plants

This account presents the views of the author on the functional and regulatory aspects of respiratory metabolism in higher plants: Control of metabolism (by enzymes) and the interaction of respiration with the other physiological functions in the living plant (metabolic control). This concept, formulated in the early fifties (ref. 47), was presented in part in 1965 (ref. 2) based on experiments performed mostly by the author and his colleagues and by his co-workers in this country. After an interruption of a decade, during which his work was discontinued, a more complete formulation of his views are given here based on results reported by workers in this field in other countries during that period. The more complete view can now be 'summarized as follows: Respiratory metabolism is the process whereby a part of the material stored in the plant (organism) is converted into biological work (function) for maintaining its state of being alive, while the other part of the same material is converted into substances of higher degrees of orderliness (negative entropy) in the form of structure and organization. Within limits imposed by the genetic potential, these processes are controlled by enzymes which in turn are regulated by internal and external factors. The above statement is essentially a special expression of a general view on the functional aspects of living organisms given in the author’s earlier book, Green Thral- dom (Alien & Unwin, London, 1949). If the above theme finds acceptance, it follows, as stated earlier (ref. 14), that: 1. Respiratory metabolic pathways must be multiple ("multilineal") and multi- directional; 2. They must be interacting, not only with themselves, but also with other functions in the plant, alternatingly in time and separately in space (compartmentation); 3. There must be mutual interactions among the pathways and func- tions regulated by enzymes which in turn are regulated through external and internal factors. This functional and regulatory concept of respiratory metabolism in higher plants are now summarized by the following expressions: 1. CH2O + O2→>Xl→X2→H2O + CO2 + E ↓↓ Y1 Y2 in which E = Energy, X1, X2 etc. represent intermediate products, and Y1, Y2 etc. represent anabolic products of different composition and different degrees of complexity. 2. Borrowing from the second law of thermodynamics, the free energy △G deri- ved from process 1 is used for performance of physiological work (function) during which part of the energy is given off in the form of heat (△H), and the other part is concerned with the change of materials of lower orderliness into form and structure with a decrease in entropy (△S): △G = △H - T△S in which T is temperature (in K). This equation may or may not be directly applicable without qualifications in our case. But the decrease in entropy with the change of degree of orderliness in the process of tissue and organ formation from formless materials holds true. 3. The third expression presents the fundamental aspects of our concept of control of metabolism by enzymes and metabolic control of physiological functions. This may be given as: Fuction Gene→ Enzymes→Metabolism→ Structurc State→ Time cource (Solid arrows denote Control) .Experimental evidences selected from the numerous published experimental results, mostly from those of our own, in support of the above scheme at the substrate level oxidation in addition to those given in an earlier account (ref. 2) are presented here. Evidences based on experiments during the past decade on multiple pathways in NADH oxidation through the electron transport chain gathered in the literature (ref. 37) during the period when our work was interrupted completes the formula- tion of our concept on respiratory metabolism at both the substrate and terminal oxidation levels. The use of this generalized concept on the functional and regulatory aspects of respiratory metabolism in higher plants for guiding further research on plant respiration and on other physiological processes, as well as the application of this concept to practical physiological and biological problems are discussed.     

母乳中的促红细胞生成素的生理功能

母乳中存在促红细胞生成素.该文介绍母乳中促红细胞生成素的含量以及来源,并着重探讨促红细胞生成素对幼仔的生理作用.     

Studies on Compensatory Adaptation of Renal Functions

Changes in the excretion of water and electrolyte in one kidney after exclusion of its partner have been studied in anesthetized dogs and rabbits. Complete clamping of the contralateral kidney pedicle or ureter results in a rapid increase in the excretion of water, sodium, potassium, chloride, calcium, phosphate and bicarbonate. This response is also observed in denervated kidneys. Pretreatment with the loop inhibitor, furosemide, does not preclude adaptation which, however, is blunted by acetazolamide, an inhibitor of proximal sodium and bicarbonate reabsorption. Free-water reabsorption during hypertonic saline diuresis is normal in the remaining kidney. Compensatory adaptation, thus, appears to be located in the proximal tubule. The regulatory response to contralateral kidney exclusion is already fully developed in one-month-old rabbits. Compensatory adaptation of electrolyte excretion is not accounted for by changes in extracellular fluid volume, plasma composition, glomerular filtration rate, effective renal plasma flow, aldosterone or vasopressin.     

Estimating the Order of a Sequence of Physiological Changes from Incomplete Data

The problem considered in this paper is the estimation of the underlying order of m physiological changes from incomplete observations. The observations are incomplete in the sense that, for each individual in the sample, only the identity, but not the order, of the first k < m changes are observed, with k varying between individuals. An application to some data on physiological changes in fish undergoing sex change is presented.     

铬的营养生理功能

三价铬是人和动物必需的微量元素。铬在吸收后主要由转铁蛋白运输。在细胞内,4个三价铬离子与apochromodulin形成有活性的hopochromodulin。hopochromodulin除了可与胰岛素和/或胰岛素受体直接结合起作用外,还可以通过激活AMPK激酶来降低细胞膜胆固醇含量,改善细胞骨架功能,促进GLUT4移位,然后又通过激活p38MAPK激酶增强GLUT4的内在活性,从而促进葡萄糖吸收。铬也可以提高生长激素轴活性,并有降低动物机体脂肪沉积、增加肌内脂肪沉积、提高瘦肉率等作用。     

Physiological Adaptation to the Loss of Amino Acid Transport Ability

A strain of Neurospora crassa devoid of constitutive amino acid transport ability can utilize arginine as the sole nitrogen source. Nitrogen starvation, presence of arginine, and mutational inactivation of the general permease are key factors in signaling production of an extracellular enzyme which removes the alpha-amino group from the amino acid.     

冬眠动物骨骼肌生理适应及机制的研究进展

非冬眠动物的骨骼肌在废用条件下会发生明显的萎缩。冬眠动物在历经数月的冬眠期骨骼肌废用后,仍能保持较完整的形态结构与良好的收缩功能,成为天然的抗废用性肌萎缩动物模型。探明冬眠动物骨骼肌对废用的生理适应机制,是生理生态学领域的重要课题之一。本文从形态结构、肌纤维类型和收缩功能等方面综述了冬眠动物对冬眠期骨骼肌废用状态的生理适应,并从蛋白质代谢、生长与分化的调控、代谢类型的调控、氧化应激以及线粒体结构与氧化能力等方面分析了冬眠期骨骼肌生理适应的可能机制。     

MicroRNA与神经系统重大疾病

目前有研究证实microRNA参与了神经系统生长发育和生理功能的调控,它也与可塑性障碍性疾病、神经系统退行性疾病、神经系统肿瘤、脑血管疾病等重大疾病的发生发展相关．随着microRNA研究领域的发展,一些重大神经系统疾病的相关发病机制将有可能被阐释．