Development of studies on the physiology of the neuroendocrine system at Kiev University

Data on development of studies in the field of physiology of the neuroendocrine system conducted at the Kiev University under the leadership of professor B. G. Novikov are presented. Hypothalamus has been studied for its significance in the control of the endocrine gland function and periodic formogenic processes.     

Advances in the Systemic Approach to Ecophysiological Studies

Advances in ecological plant physiology are reviewed in brief and its significance for agriculture and forestry is discussed. The opportunities offered by a systemic approach to multifactor experiments designed to simulate the effect of environmental conditions on biological processes occurring in intact plants are considered.     

研究性教学模式在"植物的抗逆生理"教学中的应用

阐述了研究性教学的内涵及将之引入"植物的抗逆生理"教学的必要性,并介绍了开展研究性教学活动过程,评价了其教学效果.在此基础上就研究性教学模式下研究专题的选择、学生的成绩考核指标及教师扮演的角色等内容进行了讨论.     

细胞凋亡的研究进展

细胞凋亡（apoptosis)是一种主动的细胞死亡,是机体维持自身稳定的一种基本生理机制,参与许多疾病的病理过程,具有重要的生理病理意义,近年来倍受关注,本文概括介绍有关细胞凋亡的研究进展。     

Nutritional ecology of endoparasitic insects and their hosts: An overview

The impact of insect endoparasites (parasitoids) on the physiology and behaviour of their hosts is reviewed within the context of the nutritional ecology of the parasitoids and their hosts. Alterations in the consumption, utilization and allocation of food by parasitized hosts are common, as are internal changes in their metabolic physiology. Gregarious parasitoid species frequently increase feeding by their host larvae whereas solitary parasitoid species often reduce feeding and growth of their hosts. Many parasitoid-associated changes in host physiology and behaviour are interpreted to be of adaptive significance to parasitoids. Substantial circumstantial evidence suggests, and a few direct tests of such adaptive significance indicate, that parasitoids alter their hosts in ways beneficial to their own fitness. However, most of the changes in parasitized hosts are of unknown cause and undocumented significance to the parasitoids. Several relevant hypotheses are presented, and these require extensive evaluation (often requiring novel experimental approaches) before a thorough understanding of parasitoid nutritional ecology is established.     

The physiology and mechanisms of the stress-induced changes in prolactin secretion in the rat

It is well known that stress in a number of forms induces the secretion of prolactin (PRL) in a number of species. What is not well known is that under certain conditions stress will also induce a decrease in PRL secretion. The conditions whereby stress decreases PRL are those where PRL secretion is elevated such as during the proestrous afternoon surge and during the nocturnal surge of pseudopregnancy. The physiologic significance of the stress-induced increase of PRL is suggested to be important in maintaining the competence of the immune system. The significance of the stress-induced decrease of PRL does not appear to have a major consequence on the physiology of reproduction in the rat and it is suggested that future studies be directed towards its significance in the immune system. The literature is reviewed dealing with the regulation of PRL secretion with emphasis on the factors that generate PRL surges in the rat. In addition the mechanism(s) of the stress-induced increase and decrease is (are) also examined. A hypothesis is presented suggesting an interaction between tuberoinfundibular dopamine secretion and a hypothalamic prolactin releasing factor in the generation of PRL surges and the differential effects of stress on PRL secretion.     

Clinical Physiology: Role in Studying Basic Problems of the Regulation of Renal Functions in Humans

Clinical physiology is described as a unique branch of human physiology that allows basic regulatory mechanisms of renal functions to be revealed. The analysis of physiological mechanisms that change the renal functions under the influence of endogenous or exogenous factors made it possible to detect new aspects of the regulatory system involved. The following problems are discussed: (1) the role of autacoids in the regulation of ion and water transport in the kidney; (2) the significance of functional loading tests for assessing the main components of the regulatory system of water and electrolyte balance; (3) the variety of sources of human blood hormones; and (4) the intranephron redistribution of water and electrolyte flows, which does not change their excretion by the kidney but affects the regulation of the totality of body functions.     

红树胎生现象及其对潮间带生境适应性研究进展

热带亚热带海岸潮间带的高盐、淹水、土壤缺氧和潮水冲击等不良环境因子导致了红树植物在形态、生理和生态方面的特异性 ,尤其是其独特的胎生现象。从红树植物胎生繁殖体在母体的发育过程和繁殖体落地后对潮间带生境的适应两个角度探讨了红树植物胎生现象的适应意义。红树植物的胎生现象是对潮间带盐胁迫、淹水、土壤缺氧和潮水冲击等综合生境的适应 ,而不是单独其中一种胁迫因子的适应。红树植物胎生繁殖体在母体的发育过程中通过能量积累、渗透调节、形态完善等过程为掉落以后适应潮间生境做准备 ,掉落的胎生繁殖体依靠从母体获得的能量和营养克服潮间带的盐胁迫、淹水、土壤缺氧和潮水冲击等多重胁迫。红树植物胎生繁殖体落地后的能量收支平衡是决定繁殖体定居成功与否的关键 ,而胎生现象的意义正是通过胎生繁殖体在母体发育过程中积累足够的能量和营养来适应潮间带生境。红树植物胎生繁殖体落地后苗木在潮间带滩涂的生长发育过程中存在一个能量“阈限”,能阈的高低决定于潮间带生境的恶劣程度 ,而突破能阈能力决定于胎生繁殖体所携带的能量与营养的数量。这为红树林湿地恢复提供了理论基础 ,但还需要更多的证据来支持该理论     

Skeletal Muscle Diseases: Recent Advances and Some Related Basic Problems

Recent advances in the knowledge of the structure and function of voluntary muscle and some of its diseases are reviewed on the basis of a recently published international symposium. Among the subjects discussed are: the specific metabolic role of various muscle cell constituents (e.g. sarcosomes, microsomes, sarcoplasmic reticulum); the relaxing factor system and the dual (tonic and phasic) innervation of muscle fibres; observations on the physiology of muscle training; the morphologic differential diagnosis of degenerative skeletal muscle diseases; the value of serum enzyme determinations in the early detection of muscular dystrophy and in the identification of dystrophic carriers; the classification and diagnosis of muscular hypotonias of infancy; the role of inactivity and the trophic control of the nervous system in the development of neural (or denervation) atrophies; factors influencing regeneration of muscle fibres; the significance, as a research tool, of the identification of hereditary primary muscle disease in laboratory animals.     

Catabolite regulation of antibiotic biosynthesis

Conclusion In view of the possible mediation of carbon catabolite repression of antibiotic biosynthesis by phosphorylated substances, the concept of the role of phosphorus in the regulation of secondary metabolism should be re-evaluated. Many conclusions are based on an analogy with the effect of phosphorus in animal or plant cells (for review cf. Martin 1977). However, in contrast with plant and animal physiology, the production physiology of actinomycetes, typical soil microorganisms, was studied under nonphysiological conditions of nutrient over-supply in a submerged culture. This is analogous e.g. to space biology which studies the physiology of organisms in the state of weightlessness. Both disciplines have an extremely high significance but the elucidation of basic biological regularities is to be carried out back on Earth. In conclusion we may state that a critical evaluation of our contemporary knowledge seem to support the hypothesis that the antibiotic biosynthesis in actinomycetes, as well as the spore formation in bacilli — both regulated by the mechanism of catabolite repression — has its ecological significance, i.e. makes it possible for the organism to survive under conditions when vegetative growth is limited. For this reason this aotivity was preserved in the course of evolution as a protective mechanism of microbial populations and remained a part of the genome of many species.     

Neuroendocrine effects of light

The light/dark cycle to which animals, and possibly humans, are exposed has a major impact on their physiology. The mechanisms whereby specific tissues respond to the light/dark cycle involve the pineal hormone melatonin. The pineal gland, an end organ of the visual system in mammals, produces the hormone melatonin only at night, at which time it is released into the blood. The duration of elevated nightly melatonin provides every tissue with information about the time of day and time of year (in animals that are kept under naturally changing photoperiods). Besides its release in a circadian mode, melatonin is also discharged in a pulsatile manner; the physiological significance, if any, of pulsatile melatonin release remains unknown. The exposure of animals including man to light at night rapidly depresses pineal melatonin synthesis and, therefore, blood melatonin levels drop precipitously. The brightness of light at night required to depress melatonin production is highly species specific. In general, the pineal gland of nocturnally active mammals, which possess rod-dominated retinas, is more sensitive to inhibition by light than is the pineal gland of diurnally active animals (with cone-dominated retinas). Because of the ability of the light/dark cycle to determine melatonin production, the photoperiod is capable of influencing the function of a variety of endocrine and non-endocrine organs. Indeed, melatonin is a ubiquitously acting pineal hormone with its effects on the neuroendocrine system having been most thoroughly investigated. Thus, in nonhuman photoperiodic mammals melatonin regulates seasonal reproduction; in humans also, the indole has been implicated in the control of reproductive physiology.Summary of a Plenary Lecture presented by the author in Vienna, August, 1990     

Effects of glucose and acetylcholine on islet tissue NADH and insulin release.

The relationship between islet tissue NADH and insulin release resulting from glucose or acetylcholine was investigated with the isolated perfused rat pancreas. Switching the perfusate from 4 to 16 mM glucose or adding 1 μM acetylcholine to 4.4 mM basal glucose elicited biphasic insulin release and rapidly elevated the NADH content of islet tissue, suggesting that intermediary metabolism was stimulated. The biochemical basis for this NADH increase and its significance in islet physiology are discussed.     

Understanding circadian rhythmicity in Neurospora crassa: from behavior to genes and back again

Circadian clocks have been described in organisms ranging in complexity from unicells to mammals, in which they function to control daily rhythms in cellular activities and behavior. The significance of a detailed understanding of the clock can be appreciated by its ubiquity and its established involvement in human physiology, including endocrine function, sleep/wake cycles, psychiatric illness, and drug tolerances and effectiveness. Because the clock in all organisms is assembled within the cell and clock mechanisms are evolutionarily conserved, simple eukaryotes provide appropriate experimental systems for dissecting the clock. Significant progress has been made in deciphering the circadian system in Neurospora crassa using both genetic and molecular approaches, and Neurospora has contributed greatly to our understanding of (1) the feedback cycle that comprises a circadian oscillator, (2) the mechanisms by which the clock is kept in synchrony with the environment, and (3) the genes that reside in rhythmic output pathways. Importantly, the lessons learned in Neurospora are relevant to our understanding of clocks in higher eukaryotes.     

Physiology, biomedicine, medicine

The physiology throughout centuries was considered as the basic fundamental science in medicine. Rapid development of molecular biology, genetics and of some other natural sciences in 2nd half XX demanded century not only the answer to a question on the sciences defining the base of development of medicine, but also key problems of its progress. The biomedicine is formed, its methods are discussed, is frequent in system of natural sciences, parities with physiology. The special attention is given unconditional necessity of finding-out of molecular mechanisms of functions, targets of action of physiologically active substances and obligatory correlation of data of modeling with the same processes in conditions in vivo in whole body. The role of various sciences in the decision of fundamental problems of medicine, a place and role of physiology in modern medicine is shown.     

Calcitonin, an enigmatic hormone: does it have a function?

This editorial presents our view of the status of thyroidal calcitonin (TCT) in mammalian physiology. The discovery of calcitonin (CT) enabled the development of a valuable therapeutic agent but the early experiments most likely misled us with regard to its physiological significance. These early purported roles for TCT, first as an agent important in blood calcium regulation and later as an agent to prevent hypercalcemia, are no longer considered as physiological functions. While large supraphysiological doses of CT have an effect on the morphology and function of osteoclasts, it is unlikely that these effects of CT are important in the normal physiology of osteoclasts or bone remodeling. It is surprising that 38 years after the discovery of TCT there is no consensus as to its role in normal mammalian physiology. This editorial concerns three possibilities with respect to TCT: 1) the hormone is vestigial; 2) the hormone plays a role in water metabolism, ionic concentrations, and/or acid-base balance, actions that may not involve calcium metabolism at all; and 3) TCT acts to store phosphate postprandially on bone surfaces as a labile calcium-phosphate colloid, an action that may provide calcium needed for use in non-feeding periods or to reduce postprandial loss of phosphate when dietary phosphate is limited. Also discussed are recent publications indicating that CT synthesized in non-thyroidal tissues (NTCT) may have paracrine actions.     

Starting a new genetic system: lessons from bacteroides

Despite the fact that genetic manipulation is an essential adjunct of studies of microbial physiology, many important bacterial species are still not accessible to genetic manipulation. In many cases, the people who know the organism best and have studied its physiology extensively have little experience with genetic techniques and are uncertain how to set up a new system. In this article, we describe what we have learned in the process of developing a genetic system for Bacteroides spp. and helping to develop genetic tools for two related species of bacteria: Porphromonas gingivalis and Prevotella ruminicola. We discuss the relative usefulness of different types of genetic tools and make some suggestions about how to construct them.     

Renal and urinary proteomics: current applications and challenges

During the past few years, proteomics has been extensively applied to various fields of medicine including nephrology. Current applications of renal and urinary proteomics are to better understand renal physiology, to explore the complexity of disease mechanisms, and to identify novel biomarkers and new therapeutic targets. This review provides some examples and perspectives of how proteomics can be applied to nephrology and how experimental data can be linked to physiology, functional significance and clinical applications. In some instances, proteomic analysis can be utilized to generate a new hypothesis from a set of candidates that are obtained from expression studies. The new hypothesis can then be addressed rapidly by conventional molecular biology methods, as demonstrated by identification of an altered renal elastin-elastase system in diabetic nephropathy and alterations in the renal kallikrein-kallistatin pathway in hypoxia-induced hypertension. The strengths and limitations of proteomics in renal research are summarized. Optimization of analytical protocols is required to overcome current limitations. Applications of proteomics to nephrology will then be more fruitful and successful.     

Neurobiology of parasitic flatworms: how much "neuro" in the biology?

The nervous systems in the parasitic Platyhelminthes have generally been considered to be degenerate and of marginal significance, but recent studies have shown these systems to be more significant in the biology of these animals than formerly believed. There are many similarities in the construction and apparent neurochemistry of the nervous systems in the parasitic forms as well as in the free-living Turbellaria. In all forms there appears to be a large neurohormonal component. Though the nervous system appears to be important for many aspects of parasitic flatworm biology, little direct or specific information about the physiology of these systems is yet available.     

A bigger mouse? The rat genome unveiled

Rattus norvegicus is an important experimental organism and interesting to evolutionary biologists. The recently published draft rat genome sequence provides us with insights into both the rat's evolution and its physiology. We learn more about genome evolution and, in particular, the adaptive significance of gene family expansions and the evolution of rodent genomes, which appears to have decelerated since the divergence of mouse and rat. An important observation is that some regions of genomes, many in noncoding regions, show very high sequence conservation, while others show unexpectedly fast evolution. Both of these may be pointers to functional significance.