Cell biology and functional dynamics of the mammalian sperm surface

Theriogenology has now a 40-year rich history on covering sperm biological aspects with a special emphasis on farm and husbandry animals. The major and most influential of these contributions will be placed into an evolutionary perspective of ongoing and intriguing progresses made in this field. Although many molecular details have been published, it is more the aim of this contribution to provide a guide through the main established aspects and concepts of sperm surface biology and refer only to major molecular players and mechanisms involved in sperm physiology. Those interested in more molecular details and in-depth knowledge can easily access the most relevant literature which is included here for reference purposes. With this approach, a logical and easy to follow buildup can be made of the general picture of sperm surface dynamics and of the ergonomics of sperm physiology and their function in mammalian fertilization. Understanding the ins and outs of sperm surface biology and the dynamics thereof, might challenge future researchers to design novel generation of better sperm-handling procedures. This could be beneficial for assisted reproductive technology and animal breeding industries.     

植物生理生态学的学科起源与发展史

探讨了植物生理生态学的起源及其发展问题。植物生理生态学是植物生态学的一个分支,它主要是用生理的观点和方法来分析生态学现象。从现有的资料看,该门学科的创始人当为德国学者辛泊尔(A. F. W. Schimper);但近代最早建议将植物生理生态学作为独立的学科的为比林斯(W. D. Billings);拉夏埃尔(W. Larcher)为该门学科在国际上的传播起到了非常重要的作用。在中国,近代植物生理生态学的发展应归功于李继侗先生;然而,李博先生对拉夏埃尔《植物生理生态学》的翻译出版促进了该门学科在中国的传播。植物生理生态学目前在国内外发展十分迅速,由于它能够对一些生态学现象以及资源的可持续利用给以机理上的解释,因此越来越受到研究者的重视。     

Circadian organization of the diurnal Caviomorph rodent, Octodon degus

The Octodon degus, or degu, is an excellent animal model for studying the theoretical and neural underpinnings of diurnality. The power of this model comes from their unique evolutionary lineage, long lives, and relative ease of care in the laboratory for a non-domesticated species. We have summarized the field and laboratory data indicating the critical variables that influence the degus' phase preference and the possible mechanisms for the phase flexibility observed in the field and laboratory. We also review studies examining the physiology and anatomy of light and non-photic inputs to the degu circadian system and studies of the circadian pacemaker itself, with particular emphasis placed on characteristics that appear to be convergent adaptations to a diurnal niche. Finally, we begin to seek the origin for the diurnally-phased activity output of the degu, although we conclude that significant work remains to be done.     

Physiology in the mirror of systematic catalogue of Russian Academy of Sciences Library

Representation of general human and animal physiology publications in the systematic catalogue of the Library of the Russian Academy of Sciences is considered. The organization of the catalogue as applied to the problems of physiology, built on the basis of library-bibliographic classification used in the Russian universal scientific libraries is described. The card files of the systematic catalogue of the Library contain about 8 million cards. Topics that reflect the problems of general physiology contain 39 headings. For the full range of sciences including physiology the tables of general types of divisions were developed. They have been marked by indexes using lower-case letters of the Russian alphabet. For further detalizations of these indexes decimal symbols are used. The indexes are attached directly to the field of knowledge index. With the current relatively easy availability of network resources value and relevance of any catalogue are reduced. However it concerns much more journal articles, rather than reference books, proceedings of various conferences, bibliographies, personalities, and especially the monographs contained in the systematic catalogue. The card systematic catalogue of the Library remains an important source of information on general physiology issues, as well as its magistral narrower sections.     

Simulated human diving and heart rate: making the most of the diving response as a laboratory exercise

Laboratory exercises in which students examine the human diving response are widely used in high school and college biology courses despite the experience of some instructors that the response is unreliably produced in the classroom. Our experience with this exercise demonstrates that the bradycardia associated with the diving response is a robust effect that can easily be measured by students without any sophisticated measurement technology. We discuss measures that maximize the success of the exercise by reducing individual variation, designing experiments that are minimally affected by change in the response over time, collecting data in appropriate time increments, and applying the most powerful statistical analysis. Emphasis is placed on pedagogical opportunities for using this exercise to teach general principles of physiology, experimental design, and data analysis. Data collected by students, background information for instructors, a discussion of the relevance of the diving reflex to humans, suggestions for additional experiments, and thought questions with sample answers are included.     

Actual Problems of Physiology of Microorganisms

Physiology of microorganisms is traditionally considered as one of branches of microbiology. Fundamental works in this field, the last of which were written almost 40 years ago, included such issues, as chemical composition, physico-chemical properties, metabolism, respiration, reproduction, and growth of microorganisms. For the last few decades, the main efforts of scientists in these fields were concentrated on decoding molecular-genetic mechanisms underlying functioning of microbial cells. At the same time, the accumulated scientific data in adjacent fields of biological science require insistently the necessity of new understanding and systematization of results of study of processes of vital activity of all species of living organisms, based on general integrative physiological principles. By the present time, it has been convincingly proved that the existence of higher organisms is impossible without constant interaction with the world of microbes and, hence, physiology of human, animals or plants is inextricably connected with physiological processes of their inhabiting microorganisms. In the present work the main actual problems of modern physiology of microorganisms are considered, and the necessity of separation of this branch of knowledge as an autonomous part of physiology is emphasized.     

Comparative physiology in China 1984-2007

We briefly summarize the history of the rise of comparative physiology in China, the research work focused on by domestic and international counterparts in the field of comparative physiology of China, and international academic exchange and collaboration during this period. We also introduce some of the interesting model systems used in past and current research. This paper is based on documents in historical materials such as the proceedings of the 1st (August 1988) to 6th (October, 2007) Comparative Physiology Academic Session of the Chinese Association for Physiological Sciences, collected physiological works in commemoration academic papers of the 70th (1926-1999) and 80th anniversary of the Chinese Association for Physiological Sciences (1926-2006), CBP and the Physiology History of China, and the authors' own research experience.     

Sheep model in orthopedic research: a literature review

The aim of the study reported here was to provide some basic and general information on the suitability of an experimental sheep model for conducting in vivo orthopedic studies. The authors have classified the fundamental aspects that should be carefully evaluated when using sheep as an experimental model in orthopedic research: factors strictly related to bone anatomy and formation; and factors strictly affecting bone physiology, such as gastrointestinal mineral and vitamin absorption, and reproductive cycle. Future investigations should address all of the aspects highlighted, since there is no animal with the same anatomic, biochemical, physiologic, and biological characteristics as those of human beings. Moreover, useful data for treating orthopedic patients are based not only on good planning and study design, but also on perfect knowledge of the animal used and the differences between the model and the human being. The authors hope that this report will contribute to extrapolation of reliable data for use of sheep in the orthopedics field.     

Sleep as a teaching tool for integrating respiratory physiology and motor control

Sleep exerts major effects on most fundamental homeostatic mechanisms. Current data suggest, however, that students of physiology and medicine typically receive little or no formal teaching in sleep. Because sleep takes up a significant component of our life span, it is proposed that current teaching in systems and integrative physiology is not representative if it is confined to functions describing wakefulness only. We propose that sleep can be readily integrated into various components of physiology and medical curricula simply by emphasizing how commonly taught physiological processes are importantly affected by sleep mechanisms. In our experience, this approach can be used to reinforce basic physiological principles while simultaneously introducing sleep physiology into the students' training. We find that students have a general and inherent interest in sleep and related clinical disorders, and this proves useful as an effective means to teach the material. In this paper, examples of how sleep influences motor control and the respiratory system will illustrate these points. These considerations also highlight some important gaps in traditional teaching of respiratory physiology.     

The Use of Theory in Behavioural Research

A survey of recent publications in behavioural biology suggests that research in this field often lacks a formal approach linking theory and empiricism, which implies that there is scope for improvement. Frequently, hypotheses guiding empirical work are merely based on plausibility arguments, which is not necessarily wrong and may be useful especially at the early stages of an investigation. Behavioural studies based on a theoretical framework usually test qualitative predictions from a general model either with data from natural situations or by experimental scrutiny. Rarely, a quantitative approach is used where a model is parameterized by existing data and therefore generates precise, testable predictions. In general, there is a lack of awareness that much more is to be learnt from a mismatch between predictions and data than from accordance. The latter is prone to cause the ‘pseudo‐proof fallacy’, which is widespread in behavioural ecology. Behavioural physiology, on the other hand, often suffers a lack of proper theoretical models. Much can be gained in both fields if empiricists and theoreticians collaborate more closely towards the ultimate aim – to unravel the mechanisms of behaviour at both, ultimate and proximate levels.     

Isoprene research – 60 years later,the biology is still enigmatic

Isoprene emission is a major component of biosphere–atmosphere interactions. It is the single largest source of non‐methane hydrocarbon in the atmosphere. The first report of isoprene emission from plants was published in 1957 by Professor Guivi Sanadze. While humans have smelled the monoterpene hydrocarbons made by coniferous trees since their earliest migrations, only in 1957 did the world became aware that other trees make a type of hydrocarbon in even greater amounts but one to which the human nose is much less sensitive. For this 60th anniversary of the first report of isoprene emission from leaves, we trace the discovery and development of the research field, highlighting some of the most seminal observations and theoretical interpretations. This is not an exhaustive review, and many important papers are not cited, but we hope it will be of general interest to read how research in this field developed, how new observations forced us to reevaluate our theories about the significance of isoprene biosynthesis to plant physiology and adaptation and how scientific serendipity can sometimes drive a topic forward.     

Natural selection and glucocorticoid physiology

Glucocorticoid hormones are considered potent modulators of trade‐offs between reproduction and survival. As such, selection should affect glucocorticoid physiology, although relatively little is known about how selection may act on glucocorticoid profiles. In general, the evolution of physiology is less studied and less well understood than morphological or life history traits. Here, we used a long‐term data set from a population of mountain white‐crowned sparrows to estimate natural selection on glucocorticoid profiles. Our study suggests that survival selection favours higher hormone concentrations for multiple components of glucocorticoid physiology (both baseline and stress‐induced glucocorticoid levels). Fecundity selection varies depending on the component of hypothalamic–pituitary–adrenal physiology; greater reproductive output was associated with higher baseline glucocorticoid levels, but lower stress‐induced glucocorticoid levels. Additionally, the selection gradient was greater for glucocorticoids than for a morphological trait (wing length). These results support the hypothesis that stress‐induced glucocorticoids increase survival over reproduction within a wild population (the CORT‐trade‐off hypothesis). Taken together, these results add to our knowledge of how selection operates on physiological traits and also provide an evolutionary and ecological perspective on several key open issues in the field of glucocorticoid physiology.     

Genes regulating copper metabolism

The metabolism of Cu is intimately linked with its nutrition. From gut to enzymes, Cu bioavailability to key enzymes and other components operates through a complex mechanism that uses transport proteins as well as small molecular weight ligands. Steps in Cu transport through the blood, absorption by cells, and incorporation into enzymes are slowly being understood. Cloning and sequencing of the genes for Menkes disease and Wilson disease has shown that membrane-bound enzymes analogous to Cu-ATPases in prokaryotes are equally important to Cu transport and homeostasis in mammalian cells. The primary structure of the mammalian Cu-ATPases has been deduced from cDNAs from tissues and organs. It now appears that mammalian Cu-ATPase have tissue and developmental specificity. In this review, we will focus on the Cu-ATPase that has been identified with Menkes disease. An emphasis will be placed on the existence of multiple forms of the ATPase and some indication as to how the different isoforms befit their role in the normal physiology of copper, specifically transmembrane transport and maintenance of a favorable internal cellular environment.     

The scientific development of the physiology of plants in the American tropics

This paper is a research and journalistic work that summarizes and synthesizes the scientific development of the physiology of plants in the American tropics, also known as the Neotropics. It contains the contributions of numerous biologists interested in the physiology of tropical plants. The fabulous structural and functional diversity of tropical forests is still the major driver of research in this field. Classical physiological work involving tropical plants, such as the discovery of C4 photosynthesis in sugarcane, is invoked to exemplify the historical and current importance of physiological research in the tropics, and its applications in agriculture, forestry and conservation. An historical background describing the early and more recent development of a tradition on the physiological study of tropical plants is followed by a summary of the research conducted on the physiology of tropical crops. Common areas of interest and influence between the fields of crop physiology and plant ecophysiology are identified and exemplified with problems on the environmental physiology of crops like coffee and cassava. The physiology of tropical forest plants is discussed in terms of its contributions to general plant physiological knowledge in areas such as photosynthetic metabolism and plant water relations. Despite the impressive technical advances achieved during the past decade, the importance of continuous development of appropriate instrumentation to study and measure the physiology of plants in situ is stressed. Although the basic metabolic processes that underlie the mechanisms of plant responses to the environment are probably highly conserved and qualitatively similar among tropical and temperate plants, it is also apparent that tropical plants exhibit metabolic peculiarities. These include aspects of photosynthetic metabolism, phloem transport physiology, sensitivity to low temperatures, reproduction, responses to climatic seasonality, and a large variety of biotic interactions. Old and new paradigms are examined in light of recent evidence and comparative studies, and the conceptual and technical advances needed to foster the development of tropical plant ecophysiology are identified.     

Bombardment-mediated transformation of plant cells

Significance of bombardment-mediated transformation in plant research is discussed. Apart from general subjects related to this transformation study, a particular emphasis has been placed on the pollen and organelle transformation and on integration mechanism. Over 70 literatures related to this field are cited here.     

A Web-based course of lectures in respiratory physiology

A complete course of respiratory physiology suitable for first-year medical and graduate students has been placed on the Web for our own students and for other educational institutions. There are several reasons for doing this. The first is that the modern-day student uses a variety of options for acquiring knowledge. These include attending lectures, reading texts, iPod downloads, and surfing the internet. This Web-based course is another option that may be preferable for some students. A second reason is that it is becoming increasingly difficult for some medical schools to find faculty members who are willing and able to teach the principles of respiratory physiology. This is a potentially serious problem because a sound knowledge of respiratory physiology will always be necessary for the intelligent practice of medicine. Schools with limited faculty may find it useful to use these Web-based lectures followed by a discussion session with students. Another reason is that some schools have moved away from systematic lectures to case-based discussions, with the possibility that students will not be exposed to some of the principles of respiratory physiology. The hope is that this comprehensive course of lectures will help students to assimilate this important material as the medical school curriculum continues to expand at a rapid rate.     

Comparative biochemistry and physiology in Brazil: a critical appraisal

Brazil stood out as the country with the highest number of submissions to the editorial project dedicated to Latin America by the journal Comparative Biochemistry and Physiology. Therefore, we felt that it was important to critically discuss the state of comparative biochemistry and physiology in this country. Our study is based on data collected from the ISI Web-of-Science. We analyzed publication trends through time, availability of novel approaches and techniques, patterns of collaboration among different geographical regions, patterns of collaboration with researchers abroad, and relative efforts dedicated to the study of biochemical and physiological adaptation of native fauna representing different terrestrial Brazilian biomes. Overall, our data shows that comparative biochemistry and physiology is a lively and productive discipline, but that some biases limit the scope of the field in Brazil. Some important limitations are the very heterogeneous distribution of research nuclei throughout the country and the absence of some important approaches, such as remote sensing and the use of molecular biology techniques in a comparative or evolutionary context. We also noticed that international collaboration far surpasses interregional collaboration, and discuss the possible causes and consequences of this situation. Finally, we found that Brazilian comparative biochemistry and physiology is biome-biased, as the Amazonian fauna has received far more attention than the whole pool of fauna representing other terrestrial biomes. We discuss the possible causes of these biases, and propose some directions that may contribute to invigorate the field in the country.