Genomics and bacterial metabolism

The field of bacterial metabolism and physiology is arguably the oldest in microbiology. Much of our understanding of biological processes and molecular paradigms has its roots In early studies of prokaryotic physiology. After a period of declining interest in metabolic studies (prompted by the insurgence of molecular techniques), genomic technologies are revitalizing the study of bacterial metabolism and physiology. These new technologies bring a means to approach metabolic questions with a global perspective. When used in combination with classical and molecular techniques, emerging global technologies will make it feasible to understand the complex integration of metabolic processes that result in an efficient physiology. At the same time, without increased computational capabilities, the massive amounts of data generated by these technologies threaten to overwhelm, rather than facilitate, this work. For genomic technologies to reach their potential for increasing our understanding of bacterial metabolism, microbiologists must become more collaborative and multidisciplinary than at any time in our history.     

Molecular biology in physiology

The aim of this symposium on molecular biology in physiology was to introduce molecular biology to physiologists who had relatively little exposure to the new developments in this field, so that they can become conversant on this topic and contribute to the advancement of physiology by incorporating molecular biological approaches as a part of their research arsenal. After the discussion of the basic concepts, terminology, and methodology used in molecular biology, it was shown how these basic principles have been applied to the study of the genes encoding two membrane proteins that have important transport functions (band 3 and ATPase). The second half of the symposium consisted of papers on the state-of-the-art developments in the application of molecular biology to the studies of the atrial natriuretic factor and renin genes, adenylate cyclase-coupled adrenergic receptors, acetylcholine receptors and sodium channel, and long-term and short-term memories. The ultimate goal is that these examples will provide an impetus for the opening of new frontiers of research in physiology by taking advantage of the tools developed from recent advances in molecular biology.     

The role of insulin-like growth factors and IGF-binding proteins in the physiological and pathological processes of the kidney.

Insulin-like growth factors (IGFs) and their binding proteins are implicated in the growth regulation of the kidney during embryogenesis and differentiation. Recent evidence also suggests that IGFs play a role in kidney physiology (glomerular filtration rate, renal plasma flow) and pathology (diabetic renal hypertrophy, nephritis, glomerulosclerosis, kidney tumours, chronic renal failure). This review focuses on the biology of IGFs at the molecular, protein and receptor levels and considers their importance in renal physiology and pathology. The current data demonstrate a central role for the IGFs in the mediation of a wide variety of effects on renal growth, function and malignancy.     

Molecules are more than markers: new directions in molecular microbial ecology

Macromolecules such as DNA, RNA, and proteins are widely used to quantify diversity in natural communities, to monitor the dispersal of organisms and their genes, and to trace phylogenetic relationships among organisms. With such widespread use of molecules as markers, it is easy to forget that they perform functions that are integral to the survival of organisms. The structural and functional properties of macromolecules have been intensively studied in genetics, biochemistry, and physiology. These fields, however, have not generally focused on the ecological significance of molecular variation, but instead have used defective variants as tools for identifying structure and function. Understanding the significance of molecular variation for organismal success or failure is a central problem in ecology, one whose solution will require the integration of diverse approaches and perspectives from ecology, molecular biology, genetics, physiology, and evolutionary biology. I review several studies of bacterial populations evolving in simple environments that have begun to integrate these approaches and perspectives in order to examine the consequences of molecular variation for ecological performance.     

Effects of Psychological Stress on Innate Immunity and Metabolism in Humans: A Systematic Analysis

Stress is perhaps easiest to conceptualize as a process which allows an organism to accommodate for the demands of its environment such that it can adapt to the prevailing set of conditions. Psychological stress is an important component with the potential to affect physiology adversely as has become evident from various studies in the area. Although these studies have established numerous effects of psychological stress on physiology, a global strategy for the correlation of these effects has yet to begin. Our comparative and systematic analysis of the published literature has unraveled certain interesting molecular mechanisms as clues to account for some of the observed effects of psychological stress on human physiology. In this study, we attempt to understand initial phase of the physiological response to psychological stress by analyzing interactions between innate immunity and metabolism at systems level by analyzing the data available in the literature. In light of our gene association-networks and enrichment analysis we have identified candidate genes and molecular systems which might have some associative role in affecting psychological stress response system or even producing some of the observed terminal effects (such as the associated physiological disorders). In addition to the already accepted role of psychological stress as a perturbation that can disrupt physiological homeostasis, we speculate that it is potentially capable of causing deviation of certain biological processes from their basal level activity after which they can return back to their basal tones once the effects of stress diminish. Based on the derived inferences of our comparative analysis, we have proposed a probabilistic mechanism for how psychological stress could affect physiology such that these adaptive deviations are sometimes not able to bounce back to their original basal tones, and thus increase physiological susceptibility to metabolic and immune imbalance.     

Human physiology: The kidney

The content of human physiology as an independent part of modern physiology is discussed. It is substantiated that not only special sections of physiology where functions are specific for humans (the physiology of intellectual activity, speech, labor, and sport), but also the characteristics of functions and the specificity of regulation of each of the physiological systems are subjects of human physiology. The boundaries of the norm, the characteristics of regulation in humans, new chapters of renal physiology that appeared due to the achievements of molecular physiology and require fundamentally new approaches are exemplified by the physiology of the kidneys and water-electrolyte balance.     

Biophysical limits on athermal effects of RF and microwave radiation

Using biophysical criteria, I show that continuous radiofrequency (RF) and microwave radiation with intensity less than 10 mW/cm(2) are unlikely to affect physiology significantly through athermal mechanisms. Biological systems are fundamentally noisy on the molecular scale as a consequence of thermal agitation and are noisy macroscopically as a consequence of physiological functions and animal behavior. If electromagnetic fields are to significantly affect physiology, their direct physical effect must be greater than that from the ubiquitous endogenous noise. Using that criterion, I show that none of a set of interactions of weak fields, which I argue is nearly complete on dimensional grounds, can affect biology on the molecular scale. Moreover, I conclude that such weak fields are quite unlikely to generate significant effects in their interactions with larger biological elements such as cells. In the course of that analysis, I examine important special examples of electromagnetic interactions: "direct" interactions where biology is modified simply by the motion of charged elements generated by the electric field; resonance interactions; the effects of electrostrictive forces and induced dipole moments; and modifications of radical pair recombination probabilities. In each case, I show that it is unlikely that low intensity fields can generate significant physiological consequences.     

Human physiology: kidney

The content of human physiology as an independent part of current physiology is discussed. Substantiated is the point that subjects of human physiology are not only special sections of physiology where functions are inherent only in human (physiology of intellectual activity, speech, labor, sport), but also in peculiarities of functions, specificity of regulation of each of physiological systems. By the example of physiology of kidney and water-salt balance there are shown borders of norm, peculiarities of regulation in human, new chapters of renal physiology which have appeared in connection with achievements of molecular physiology.     

Curt Richter and regulatory physiology

Curt Richter made seminal contributions to our understanding of a number of issues regarding the relationships between physiology and behavior. He was the first to conceptualize behavior as an aspect of regulatory physiology. These ideas developed from his work on behavioral responses to a variety of physiological perturbations. The classic example is Richter's demonstration of the development of avid sodium ingestion in response to urinary sodium loss after adrenalectomy. Some of Richter's ideas on the nature and underlying physiology of specific appetites maintain their influence and continue to stimulate active investigation. Others, focused on abilities to self-select balanced diets, have not borne the test of time or experimental challenge. As current research takes a more molecular focus, Richter's ideas on behavior in the service of the internal milieu maintain their currency, and the search for the molecular bases for these relationships should serve as a research focus.     

Analysis of normal-tumour tissue interaction in tumours: prediction of prostate cancer features from the molecular profile of adjacent normal cells

Statistical modelling, in combination with genome-wide expression profiling techniques, has demonstrated that the molecular state of the tumour is sufficient to infer its pathological state. These studies have been extremely important in diagnostics and have contributed to improving our understanding of tumour biology. However, their importance in in-depth understanding of cancer patho-physiology may be limited since they do not explicitly take into consideration the fundamental role of the tissue microenvironment in specifying tumour physiology. Because of the importance of normal cells in shaping the tissue microenvironment we formulate the hypothesis that molecular components of the profile of normal epithelial cells adjacent the tumour are predictive of tumour physiology. We addressed this hypothesis by developing statistical models that link gene expression profiles representing the molecular state of adjacent normal epithelial cells to tumour features in prostate cancer. Furthermore, network analysis showed that predictive genes are linked to the activity of important secreted factors, which have the potential to influence tumor biology, such as IL1, IGF1, PDGF BB, AGT, and TGFβ.     

Plant-aphid interactions: molecular and ecological perspectives

Many aphids are major agricultural pests because of their unparalleled reproductive capacity and their ability to manipulate host plant physiology. Aphid population growth and its impact on plant fitness are strongly influenced by interactions with other organisms, including plant pathogens, endophytes, aphid endosymbionts, predators, parasitoids, ants, and other herbivores. Numerous molecular and genomic resources have recently been developed to identify sources of aphid resistance in plants, as well as potentially novel targets for control in aphids. Moreover, the same model systems that are used to explore direct molecular interactions between plants and aphids can be utilized to study the ecological context in which they occur.     

克隆植物的水分生理整合及其生态效应

水分生理整合是克隆植物生理整合过程中非常重要的一部分,是克隆植物生长发育和生态适应过程中的重要机制之一。本文主要从理论上对克隆植物水分生理整合的存在性、方向性、整合的程度、范围及其与克隆植物的功能分工、表型可塑性和觅养行为、风险分摊等行为表现的关系进行了深入分析,并对迄今有关克隆植物水分整合的最新研究进展和研究方法进行了系统总结和评述。提出克隆植物的水分生理整合包括水平和垂直两个方向,而水力提降为垂直方向的水分生理整合提供了一个重要途径。认为在今后,应加强对克隆植物水分生理整合的精确定量化研究,同时,应运用生态学、生理学、生物化学及分子生物学等方法,综合深入地研究克隆植物水分整合的机理。     

Animals and environments: resisting schisms in comparative physiology and biochemistry

The articles in this volume are a product of the enthusiasm shown by delegates to meet in a remote corner of southern Africa and to discuss comparative physiology and biochemistry in their wider interpretation and future course. This collection reflects a small but long-standing commitment to fostering the engagement of biological research with African issues and colleagues. Comparative physiology and biochemistry are evolving, but in this we must guard against fractionation of effort and purpose. Increasingly available molecular methods are seductive in encouraging work on model species and in employing these species in place of more appropriate comparative models. Concomitantly, the comparative approach is reaching out beyond the individual organism and organism-organism interactions to establish underlying principles at ecosystem and landscape levels. The integration of molecular methods into comparative studies will require judicious selection and use of such skills if it is to be achieved without abandoning nonmodel species. The physiological and metabolic bases of ecosystem and evolutionary approaches must be underpinned by relevant data, requiring comparative researchers to accommodate colleagues contributing this specialist knowledge. These articles report distinct symposia, prefaced by a plenary paper. While each paper is itself a review of an entire symposium, they all exhibit a common theme, that comparative physiology and biochemistry are about interactions. It is our hope that the Comparative Physiology and Biology in Africa meetings will continue to facilitate special interactions between the people who make this happen.     

Engineering cell physiology to enhance recombinant protein production in <Emphasis Type="Italic">Escherichia coli</Emphasis>

The advent of recombinant DNA technology has revolutionized the strategies for protein production. Due to the well-characterized genome and a variety of mature tools available for genetic manipulation, Escherichia coli is still the most common workhorse for recombinant protein production. However, the culture for industrial applications often presents E. coli cells with a growth condition that is significantly different from their natural inhabiting environment in the gastrointestinal tract, resulting in deterioration in cell physiology and limitation in cell’s productivity. It has been recognized that innovative design of genetically engineered strains can highly increase the bioprocess yield with minimum investment on the capital and operating costs. Nevertheless, most of these genetic manipulations, by which traits are implanted into the workhorse through recombinant DNA technology, for enhancing recombinant protein productivity often translate into the challenges that deteriorate cell physiology or even jeopardize cell survival. An in-depth understanding of these challenges and their corresponding cellular response at the molecular level becomes crucial for developing superior strains that are more physiologically adaptive to the production environment to improve culture productivity. With the accumulated knowledge in cell physiology, whose importance to gene overexpression was to some extent undervalued previously, this review is intended to focus on the recent biotechnological advancement in engineering cell physiology to enhance recombinant protein production in E. coli.