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1.
Efficacy of drugs in patients with pulmonary tuberculosis mostly depends on their concentration in organs and tissues. To show distribution profiles of antituberculous drugs in patients in organs and tissues of experimental animals after their administration alone or in combination, pharmacokinetic parameters of isoniazid and rifampicin were studied. The drug concentrations, half-lives and distribution volumes were determined in 50 patients and 60 experimental animals. It was observed that after combined use of isoniazid and rifampicin their concentrations in the lung tissue and liver of the experimental animals increased which led to increasing their half-lives in patients.  相似文献   

2.
Aquatic and semi-aquatic plants comprise few species worldwide, yet the introduction of non-indigenous plants represents one of the most severe examples of biological invasions. My goal is to compare the distribution and the biology of aquatic and semi-aquatic plants in their introduced ranges and in their native ranges. The primary objective of this study is to test the hypothesis that invasive species have evolved traits likely to increase their success in the new range. I made two reciprocal comparisons, i.e. I compared European species in France and in North America, and North American species in France and in North America. Twenty-seven species were classified according to their invasiveness in their introduced area. I␣found six invasive macrophyte species in France native to North America and 17 invasive species in North America native to Europe. Four species are invasive in both areas. There is no general tendency for macrophytes to be more vigorous in their introduced ranges. Most non-indigenous aquatic and semi-aquatic species are potentially invasive or widespread and well-established in their introduced country, while few species seem to be restricted in their distribution.  相似文献   

3.
Testosterone, and winning and losing in human competition   总被引:9,自引:4,他引:5  
Testosterone and cortisol were measured in six university tennis players across six matches during their varsity season. Testosterone rose just before most matches, and players with the highest prematch testosterone had the most positive improvement in mood before their matches. After matches, mean testosterone rose for winners relative to losers, especially for winners with very positive moods after their victories and who evaluated their own performance highly. Winners with rising testosterone had higher testosterone before their next match, in contrast to losers with falling testosterone, who had lower testosterone before their next match. Cortisol was not related to winning or losing, but it was related to seed (top players having low cortisol), and cortisol generally declined as the season progressed. These results are consistent with a biosocial theory of status.  相似文献   

4.
Spatio-temporal differentiation and sociality in spiders   总被引:1,自引:0,他引:1  
Species that differ in their social system, and thus in traits such as group size and dispersal timing, may differ in their use of resources along spatial, temporal, or dietary dimensions. The role of sociality in creating differences in habitat use is best explored by studying closely related species or socially polymorphic species that differ in their social system, but share a common environment. Here we investigate whether five sympatric Anelosimus spider species that range from nearly solitary to highly social differ in their use of space and in their phenology as a function of their social system. By studying these species in Serra do Japi, Brazil, we find that the more social species, which form larger, longer-lived colonies, tend to live inside the forest, where sturdier, longer lasting vegetation is likely to offer better support for their nests. The less social species, which form single-family groups, in contrast, tend to occur on the forest edge where the vegetation is less robust. Within these two microhabitats, species with longer-lived colonies tend to occupy the potentially more stable positions closer to the core of the plants, while those with smaller and shorter-lived colonies build their nests towards the branch tips. The species further separate in their use of common habitat due to differences in the timing of their reproductive season. These patterns of habitat use suggest that the degree of sociality can enable otherwise similar species to differ from one another in ways that may facilitate their co-occurrence in a shared environment, a possibility that deserves further consideration.  相似文献   

5.
The quantitative parameters of the new-born calves acid-alkali balance in the early period of their life has been defined to be essentially changed. Considering the latter their organism acid-base balance natural stabilization is characterized by the certain dynamics which is being disturbed displays a quick development of adaptive reactions. The new-born ones' organism capability to support the acid-base homeostasis has been identified as considerably determined by their tissues alkaline reserve level.  相似文献   

6.
Using the ecological and natural-science approaches, the authors have come to the conclusion that microorganisms, pathogenic for humans (animals), are their parasites for whom the disease of their biological host is the necessary condition of their existence as a biological species. And accordingly, microorganisms, opportunistic in humans (animals) are their parasites and commensals, as well as saprophytes, for whom the disease of their host is not the necessary condition of their existence in nature. The biological host is a symbion necessary for the existence of pathogenic and most opportunistic microorganisms, but for a pathogenic microorganism the disease of the host is the result of symbiotic relationships, while for an opportunistic microorganism the disease of the host is the consequence of disturbances in symbiotic relationships. Such view of pathogenicity is important for creating a scientifically grounded theory of the liquidation of human infectious diseases.  相似文献   

7.
Transgenic Research - Transgenic crops have been the recipient of strong support as well as vigorously opposed opinions since their appearance. In any case, their growth throughout the world has...  相似文献   

8.
414 adoptees were located in a population of 28,879 males born within a 4-year period from January 1, 1944 to December 31, 1947 whose mothers were officially resident in Copenhagen, Denmark when they gave birth. For all of these males, 2 social class ratings were obtained, based upon their occuppations at age 25-28 and 35-38. A single rating was obtained for their fathers, based upon occupation at the time of birth of the population males. In the case of adoptees, this rating wass obtained for both the biological and the adoptive fathers. The adoptees had, at both ages, an average social class not deviating from the population at large. Their biological fathers were, however, below average paternal social class and their adoptive fathers were above it. Positive correlations for social class were found between the adoptees, at both ages, and their biological and adoptive fathers. The social class of adoptees is less well predicted by that of their biological and adoptive fathers, even when these are taken jointly, than the social class of sons in the population is predicted by that of their fathers. Evidence from both the group means and the correlations suggests that the adoptees at age 35-38 came to resemble their biological fathers in social class more than they had done at age 25-28.  相似文献   

9.
As we come to the end of 2011, Genome Biology has asked some members of our Editorial Board for their views on the state of play in genomics. What was their favorite paper of 2011? What are the challenges in their particular research area? Who has had the biggest influence on their careers? What advice would they give to young researchers embarking on a career in research?  相似文献   

10.
昆虫内共生菌及其功能研究进展   总被引:4,自引:0,他引:4  
昆虫内共生菌与宿主之间的互作关系已逐渐成为昆虫学的研究热点之一。昆虫内共生菌具有协助宿主营养代谢、 逃避天敌攻击和增强抗药性等功能: 通过协助宿主营养代谢, 提供食物中缺乏的营养物质来弥补食物中营养物质的不足; 分泌抗菌肽、 毒素等物质以增强对外源寄生物等的防御能力, 抑制对宿主的不利影响; 同时, 也可以增强宿主抗逆性, 调控植物生理反应, 抑制植物对宿主的不利影响; 利用对抗逆性基因精确的表达调控来增强宿主抗药性等。因此, 内共生菌介导的宿主生物学性状的改变, 扩大了宿主昆虫的生态位, 成为昆虫生长发育过程中的重要调控因子。目前, 昆虫内共生菌的功能往往是通过研究宿主感染共生菌前后性状的变化而证实。近几年, 转录组学、 蛋白质组学、 基因组学等技术的进步, 促进了内共生菌与宿主昆虫共生机制研究的发展。通过研究内共生菌及其功能基因在昆虫种群动态中的作用, 特别是内共生菌感染对宿主生殖、 存活、 适应环境能力的影响, 将有利于揭示内共生菌与宿主的共生机制, 并最终为开发新的防控技术提供理论依据。本文针对昆虫内共生菌的功能进行了综述, 并对日后的研究方向进行了展望, 提供了研究昆虫内共生菌与宿主互作关系的方法及建议。  相似文献   

11.
Microbes collectively shape their environment in remarkable ways via the products of their metabolism. The diverse environmental impacts of macro-organisms have been collated and reviewed under the banner of ‘niche construction’. Here, we identify and review a series of broad and overlapping classes of bacterial niche construction, ranging from biofilm production to detoxification or release of toxins, enzymes, metabolites and viruses, and review their role in shaping microbiome composition, human health and disease. Some bacterial niche-constructing traits can be seen as extended phenotypes, where individuals actively tailor their environment to their benefit (and potentially to the benefit of others, generating social dilemmas). Other modifications can be viewed as non-adaptive by-products from a producer perspective, yet they may lead to remarkable within-host environmental changes. We illustrate how social evolution and niche construction perspectives offer complementary insights into the dynamics and consequences of these traits across distinct timescales. This review highlights that by understanding the coupled bacterial and biochemical dynamics in human health and disease we can better manage host health.  相似文献   

12.
Adoption and Kinship in Oceania   总被引:1,自引:0,他引:1  
The frequency and form of adoption practices in Oceania recently have been cited as evidence that human behavior is inconsistent with predictions derived from sociobiological theory (Sahlins 1976). Ethnographic data reviewed here, however, suggest otherwise. In Oceania kinship is an important factor in the selection and treatment of adopted children as adoption occurs almost exclusively among close relatives. Natal children often ally against their adopted siblings over the division of their common parents' estate while adoptive parents themselves frequently apportion their land unequally among their natal and adopted children. These patterns and other data are consistent with predictions generated by a socio biological model of adoptive decisions. The model illustrates how kinship facilitates adoption as a means of modifying extreme family sizes, and how asymmetries in the degrees of relatedness between parents and their adopted and natal children provide the basis of differential treatment of them. Adoption in Oceania provides an example of a clearly cultural behavior which is consistent with socio biological predictions, and suggests that both culture and biology are relevant to an understanding of human behavior . [sociobiology, kinship, adoption, Oceania]  相似文献   

13.
In this paper, longitudinal data from northern Ghana is used to assess the effects of encouragement to use family planning that men receive from their personal network partners on the adoption of modern contraception by their wives. The study tests a conceptual model that, in addition to the effect of men's network encouragement, incorporates the effect of encouragement to use family planning that women receive from their respective network partners and the effect of spousal communication on reproductive matters and approval of family planning. Results show that encouragement received by men from their social networks significantly increases the likelihood of subsequent contraceptive use by their wives but this effect operates primarily by galvanizing spousal communication on reproductive matters. The effect of encouragement received by women from their respective network partners is largely independent from the effect of male network encouragement but it influences contraceptive adoption both directly and through spousal communication.  相似文献   

14.
Traditional interpretations of the evolution of animal societies have suggested that their structure is a consequence of attempts by individuals to maximize their inclusive fitness within constraints imposed by their social and physical environments. In contrast, some recent re-interpretations have argued that many aspects of social organization should be interpreted as group-level adaptations maintained by selection operating between groups or populations. Here, I review our current understanding of the evolution of mammalian societies, focusing, in particular, on the evolution of reproductive strategies in societies where one dominant female monopolizes reproduction in each group and her offspring are reared by other group members. Recent studies of the life histories of females in these species show that dispersing females often have little chance of establishing new breeding groups and so are likely to maximize their inclusive fitness by helping related dominants to rear their offspring. As in eusocial insects, increasing group size can lead to a progressive divergence in the selection pressures operating on breeders and helpers and to increasing specialization in their behaviour and life histories. As yet, there is little need to invoke group-level adaptations in order to account for the behaviour of individuals or the structure of mammalian groups.  相似文献   

15.
Brian Alters 《Evolution》2010,3(2):231-235
Instructors’ apprehensions and the decisions instructors make about pedagogy are often linked when it comes to teaching evolution. Whether it is the reticence of K-12 teachers that their instruction may affect their students’ religious beliefs detrimentally or that they may become caught up in some administrative, media, parental, or school political turmoil or whether it is the apprehension of college students who perceive that their religious beliefs are being explicitly challenged, such fears can be reduced by understanding their roots and by honing pedagogy in ways that reduce perceived threats. This article describes why it is prudent to address these often secretly held apprehensions and how to help instructors feel free to employ their best pedagogical methods to teach evolution without lingering fear. Some suggestions are given for pre-college and college instructors interested in combining effective pedagogy with as little perceived threat as possible. Methods are offered that allow instructors to focus on underlying scientific misconceptions even if those misconceptions are ultimately facilitated by non-scientific sources, while giving creationist or creationist-leaning students a chance to learn the appropriate scientific conceptions without their religious beliefs being explicitly threatened in a science course.  相似文献   

16.
Current status of defensins and their role in innate and adaptive immunity   总被引:27,自引:0,他引:27  
Naturally occurring antimicrobial cationic polypeptides play a major role in innate and adaptive immunity. These polypeptides are found to be either linear and unstructured or structured through disulfide bonds. Among the structured antimicrobial polypeptides, defensins comprise a family of cysteine-rich cationic polypeptides that contribute significantly to host defense against the invasion of microorganisms in animals, humans, insects and plants. Their wide-spread occurrence in various tissues of these diverse organisms, and their importance in innate and adaptive immunity have led to their identification, isolation and characterization. A large volume of literature is available on defensins' occurrence, structural characterization, gene expression and regulation under normal and pathological conditions. Much has also been published regarding their antimicrobial, antiviral and chemoattractive properties, and their molecular and cellular interactions. In this review, we describe the current status of our knowledge of defensins with respect to their molecular, cellular and structural biology, their role in host defense, future research paradigms and the possibility of their utilization as a new class of non-toxic antimicrobial agents and immuno-modulators.  相似文献   

17.
In plants several ‘starch-related’ enzymes exist as plastid- and cytosol-specific isoforms and in some cases the extraplastidial isoforms represent the majority of the enzyme activity. Due to the compartmentation of the plant cells, these extraplastidial isozymes have no access to the plastidial starch granules and, therefore, their in vivo function remained enigmatic. Recently, cytosolic heteroglycans have been identified that possess a complex pattern of the monomer composition and glycosidic bonds. The glycans act both as acceptors and donors for cytosolic glucosyl transferases. In autotrophic tissues the heteroglycans are essential for the nocturnal starch-sucrose conversion. In this review we summarize the current knowledge of these glycans, their interaction with glucosyl transferases and their possible cellular functions. We include data on the heteroglycans in heterotrophic plant tissues and discuss their role in intracellular carbon fluxes that originate from externally supplied carbohydrates.  相似文献   

18.
Adhesion events mediated by cadherin and integrin adhesion receptors have fundamental roles in the maintenance of the physiological balance of epithelial tissues, and it is well established that perturbations in their normal functional activity and/or changes in their expression are associated with tumorigenesis. Over the last decades, increasing evidence of a dynamic collaborative interaction between these complexes through their shared interactions with cytoskeletal proteins and common signaling pathways has emerged not only as an important regulator of several aspects of epithelial cell behavior, but also as a coordinated adhesion module that senses and transmits signals from and to the epithelia surrounding microenvironment. The tight regulation of their crosstalk is particularly important during epithelial remodeling events that normally take place during morphogenesis and tissue repair, and when defective it leads to cell transformation and aggravated responses of the tumor microenvironment that contribute to tumorigenesis. In this review we highlight some of the interactions that regulate their crosstalk and how this could be implicated in regulating signals across epithelial tissues to sustain homeostasis.  相似文献   

19.
Adhesion events mediated by cadherin and integrin adhesion receptors have fundamental roles in the maintenance of the physiological balance of epithelial tissues, and it is well established that perturbations in their normal functional activity and/or changes in their expression are associated with tumorigenesis. Over the last decades, increasing evidence of a dynamic collaborative interaction between these complexes through their shared interactions with cytoskeletal proteins and common signaling pathways has emerged not only as an important regulator of several aspects of epithelial cell behavior, but also as a coordinated adhesion module that senses and transmits signals from and to the epithelia surrounding microenvironment. The tight regulation of their crosstalk is particularly important during epithelial remodeling events that normally take place during morphogenesis and tissue repair, and when defective it leads to cell transformation and aggravated responses of the tumor microenvironment that contribute to tumorigenesis. In this review we highlight some of the interactions that regulate their crosstalk and how this could be implicated in regulating signals across epithelial tissues to sustain homeostasis.  相似文献   

20.
C M Visser 《Origins of life》1982,12(2):165-179
The evolutionary information obtained from sequencing proteins and RNA's fades out completely for early periods in evolution. Information for tracing evolution even further could stem from the analysis of coenzyme mechanisms. Likewise, placing cofactors in their proper evolutionary context gives new hints concerning their actual mechanisms of catalysis.  相似文献   

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