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1.
The question is discussed as to the reason why some animal societies, such as bees or ants, are sexually differentiated, that is, onlysome of its members are exhibiting reproducing activities. It is indicated that human society may be on its way to such a sexual differentiation which may eventually come.  相似文献   

2.
Prostate cancer is the second most frequently diagnosed cancer and the sixth leading cause of death from cancer in men. Epithelial-mesenchymal transition (EMT) is a process by which cancer cells invade and migrate, and is characterized by loss of cell-cell adhesion molecules such as E-cadherin and increased expression of mesenchymal proteins such as vimentin; EMT is also associated with resistance to therapy. Snail, a master regulator of EMT, has been extensively studied and reported in cancers such as breast and colon; however, its role in prostate cancer is not as widely reported. The purpose of this review is to put together recent facts that summarize Snail signaling in human prostate cancer. Snail is overexpressed in prostate cancer and its expression and activity is controlled via phosphorylation and growth factor signaling. Snail is involved in its canonical role of inducing EMT in prostate cancer cells; however, it plays a role in non-canonical pathways that do not involve EMT such regulation of bone turnover and neuroendocrine differentiation. Thus, studies indicate that Snail signaling contributes to prostate cancer progression and metastasis and therapeutic targeting of Snail in prostate cancer holds promise in �future.  相似文献   

3.
Prostate cancer is the second most frequently diagnosed cancer and the sixth leading cause of death from cancer in men. Epithelial-mesenchymal transition (EMT) is a process by which cancer cells invade and migrate, and is characterized by loss of cell-cell adhesion molecules such as E-cadherin and increased expression of mesenchymal proteins such as vimentin; EMT is also associated with resistance to therapy. Snail, a master regulator of EMT, has been extensively studied and reported in cancers such as breast and colon; however, its role in prostate cancer is not as widely reported. The purpose of this review is to put together recent facts that summarize Snail signaling in human prostate cancer. Snail is overexpressed in prostate cancer and its expression and activity is controlled via phosphorylation and growth factor signaling. Snail is involved in its canonical role of inducing EMT in prostate cancer cells; however, it plays a role in non-canonical pathways that do not involve EMT such regulation of bone turnover and neuroendocrine differentiation. Thus, studies indicate that Snail signaling contributes to prostate cancer progression and metastasis and therapeutic targeting of Snail in prostate cancer holds promise in ?future.  相似文献   

4.
We have investigated cytotoxic action of p-aminobenzhydrazide and its influence on biosynthesis of nucleic acids in cultures of intact cells, tumor cells and intact cells stimulated by phytohemagglutinin. p-Aminobenzhydrazide is considered as a representative of hydrazine's derivatives (in particular, of hydrazine sulphate). We compare its action with that of a typical cytotoxic agent such as iododeoxyuridine. We have found that p-aminobenzhydrazide influences biosynthesis of nucleic acids in the same way as iododeoxyuridine. However it acts toxically on tumor cells though it is not toxic for intact cells so that its action is different as compared to that of cytotoxic agents. Specific toxic action of aminobenzhydrazide on tumor cells may be due to the enhancement of antitumor activity substances of this compound and absence of such enhancement of side toxic effects.  相似文献   

5.
The Molecular Interactive Display and Simulation (MIDAS) system is designed to display and manipulate large macromolecules, such as proteins and nucleic acids. Several ancillary programs allow for such features as computing the surface of a molecule, selecting an active site region within a molecule, and computing electrostatic charge potentials. At the core of MIDAS is a hierarchical database system, designed specifically for macromolecules, that is both compact in its storage requirements and fast in its data access.  相似文献   

6.
Mushrooms are regarded as one of the well-known foods and biopharmaceutical materials with a great deal of interest. beta-Glucan is the major component of mushrooms that displays various biological activities such as antidiabetic, anticancer, and antihyperlipidemic effects. In this study, we explored the molecular mechanism of its immunostimulatory potency in immune responses of macrophages, using exopolysaccharides prepared from liquid culture of Lentinus edodes. We found that fraction II (F-II), with large molecular weight protein polysaccharides, is able to strongly upregulate the phenotypic functions of macrophages such as phagocytic uptake, ROS/NO production, cytokine expression, and morphological changes. F-II triggered the nuclear translocation of NF-kappaB and activated its upstream signaling cascades such as PI3K/ Akt and MAPK pathways, as assessed by their phosphorylation levels. The function-blocking antibodies to dectin-1 and TLR-2, but not CR3, markedly suppressed F-II-mediated NO production. Therefore, our data suggest that mushroom-derived beta-glucan may exert its immunostimulating potency via activation of multiple signaling pathways.  相似文献   

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In this paper, I aim to show that the multiple realisability and the causal efficacy of biological events can best be explained by construing biological events as determinables of more determinate physical events. The determination relation itself is spelled out in terms of inclusive essence. In order to secure actual causation for biological events (in contrast to causal influence), two conditions are introduced such that for some events, biological events qualify as their cause. Finally, certain consequences of the presented theory are discussed, such as the question of how the biological token event can retain its identity across modal modifications of its realiser, and such as how the presented solution bears on the classical problem of biological causation.  相似文献   

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11.
Propolis (bee glue) is a bee glue, sticky resinous material released from various plant sources such as bud exudates, flowers, and leaves modified by bee secretions and wax propolis is composed of resins, waxes, polyphenols, polysaccharides, volatile materials, and secondary metabolites that are responsible for various bioactivity such as antibacterial, anti-angiogenic, antiulcer, anti-inflammatory, antioxidant, and anti-viral activities. The physico-chemical characteristics and the natural properties of various kinds of propolis have been studied for the past decade. Novel active anti-microbial compounds have been identified in propolis. Those compounds positively modulated the antimicrobial resistance of multidrug resistant bacteria. Published research has indicated that propolis and its derivatives has many natural antimicrobial compounds with a broad spectrum against different types of bacteria and that it enhanced the efficacy of conventional antibiotics. Besides, the combination of propolis with other compounds such as honey has been studied whereby, such combinations have a synergistic effect against bacterial strains such as Escherichia coli and Staphylococcus aureus. The activity of propolis is very much dependent on seasonal and regional factors, and Middle Eastern propolis have shown best antibacterial efficacy. Propolis and its main flavonoids ingredients should not be overlooked and should be evaluated in clinical trials to better elucidate their potential application in various fields of medicine. Clinical antibacterial potential and its use in new drugs of biotechnological products should be conducted. This review aims at highlighting some of the recent scientific findings associated with the antibacterial properties of propolis and its components.  相似文献   

12.
The accumulation of organic solutes is a prerequisite for osmotic adjustment of all organisms. Archaea synthesize unusual solutes such as beta-amino acids, Nepsilon-acetyl-beta-lysine, mannosylglycerate and di-myo-inositol phosphate but, as in other cells, uptake of solutes such as glycine betaine is preferred over de novo synthesis. Study of the molecular basis of osmoadaptation and its regulation in archaea is still in its infancy, but genomics and functional genome analyses combined with classical biochemistry shed light on the processes that confer osmoadaptation in archaea. Most interestingly, some solutes are not only produced in response to salt but also to temperature stress.  相似文献   

13.
The knowledge practices of social and cultural anthropology can be conceived as undergoing constant methodological reconsideration or reformulation as a consequence of internal critique and of institutional change effected in the larger educational and political environment. Neo‐liberal shifts affecting the institutional context may have influenced a deepening of the crisis in anthropology where the nature of its project has become less certain or has threatened a reconfiguration of such proportion that anthropology may be losing sight of its direction. This essay explores some of the Enlightenment roots of social and cultural anthropology. It is presented as very much an idea that embodies and reflects what Adorno and Horkheimer discussed as the dialectic of Enlightenment. The argument presented is less pessimistic claiming that the distinction of anthropology is in its pursuit of Enlightenment ideals that it has maintained and rehoned as a consequence of its own routine internal critique. The vital implication of the discussion is that anthropology is in a situation of serious threat in largely a post‐Enlightenment world. In such a context, the methodological ideals that emerged as integral to the spirit of anthropology are well worth maintaining rather than abandoning. The ideals that are addressed are conceived to be integral to the importance of anthropology as critique and as a knowledge practice capable of sustaining a profound contribution to the understanding of the potential that is human being.  相似文献   

14.
The process of language revitalization relies heavily on education in its broadest sense. That is, there must be a viable conduit for the transmission of communicative competence, and any individual who contributes to that process is an educator. This article deals with the responsibility of such educators with respect to the quality of the product they intend to transmit. In particular, they must address the issue of authenticity, especially in the case of Hawaiian in which the shift to English has almost run its full course. It is inevitable in efforts to recover and maintain a language in a community in which few competent speakers (experts) remain that competing opinions will arise as to the direction such efforts should take, each professing to be better informed than the other and each pointing to its link to traditional forms as verification of its authenticity.  相似文献   

15.
Abstract

Nowadays, levan synthesis and its biocatalysis is a step claiming attention due to its promising uses in biomedical field. Levansucrase, as the enzyme responsible of levan biocatalysis is studied in this work concerning sequence homology, signal peptide, metal binding, etc. More than 650 different levansucrase sequences were studied and many interesting results were obtained such as phylogenetic trees and conserved residues that could be essential for biocatalysis machinery. Moreover, a review of levan applications in biomedicine and health field was made. It is showed the advances in applications such as a film agent, a carrier for drug delivery systems, an anti-inflammatory compound or its potential use for functional food as prebiotic.  相似文献   

16.
Sclerostin has been identified as a negative regulator of bone growth. Initially it was considered that Sclerostin performs its regulatory function via acting as a modulator of bone morphogenetic proteins (BMPs) similar to known examples such as Noggin, Chordin, and members of the DAN family. Recent findings, however, show that Sclerostin interferes with the Wnt signaling pathway due to binding to the Wnt co-receptor LRP5 thereby modulating bone growth. As Sclerostin is exclusively produced by osteocytes located in bones, neutralization of its bone-inhibiting functions makes it a highly interesting target for an osteoanabolic therapeutic approach in diseases characterized by bone loss, such as osteoporosis. Despite the huge interest in Sclerostin inhibitors the molecular basis of its function and its interaction with components of the Wnt signaling cascade has remained unclear. Here, we present the NMR structure of murine Sclerostin providing the first insights how Sclerostin might bind to LRP5.  相似文献   

17.
Transmembrane protein CD36 is considered to bind its distinct ligands such as long-chain fatty acids primarily by recognizing their terminal carboxyl moiety. In this study, we provide evidence that long-chain fatty aldehydes, such as oleic aldehyde, can be recognized by CD36. We suggest that a single aldehyde group may also serve as one of the structural elements recognizable by CD36.  相似文献   

18.
Nav1.5α亚单位是电压-门控Nav1.5Na+通道发挥作用的核心亚单位,在心肌中首先被成功克隆,是心脏电生理活动最主要的Na+通道α亚单位.最新的研究发现,Nav1.5不仅可以在神经元等非心肌组织中表达,而且其表达的选择性剪接体的类型及电生理学特性与心肌Nav1.5亦不同.目前,不仅对Nav1.5发挥功能的调控机制及与心脏传导功能障碍等疾病的发病关系有了深入的了解,而且一些常见疾病,如肿瘤和癫痫等的发生也被认为可能和Nav1 .5有关. 本文结合国内外对Nav1.5的最新研究及本小组的工作,对Nav1.5的结构、选择 性剪接、基因定位、电生理学活性及与疾病的关系作一详细综述.  相似文献   

19.
A possibility to put a question of truth of knowledge in biological systematics is studied. It is shown that the problem of truth in reference to systematics is wider than a question of classified information reliability. Prerequisites needed for logically accurate formulation of a definition and criteria of truth are considered. It is shown that such prerequisites are present in taxonomic practice, namely in a process of diagnosis compiling. Philosophical analysis of this work has been carried out. Interpretation of an essence of systematics as classification is connected with use of classical concept of truth (which defines truth as correspondence between knowledge and object) in its undeveloped form. Carried analysis allows supposing that a theory of systematics based on diagnostics rather than on classification would be more prospective. Use of imperfect concept of truth can be seen also in notions that system of taxa must reflect its evolutionary history. Development and modernization of Aristotle's orientation to discovery of the object form can become an alternative to such opinions. An aspiration to achieve the truth is the main motive of systematic work. An influence of this aspiration on a selection of purposes of taxonomic work and theoretical comprehension of its bases is shown. Such features of modern biological systematics as its accessibility for new results, criticism in respect of external morphological characters, and interest in intraspecific variability are connected with this aspiration. This motive comes into contradiction with a tendency to withdraw the problem of truth as such, which takes place in some brunches of theoretic systematics.  相似文献   

20.
The area postrema is a circumventricular organ of the fourth ventricle of the mammalian brain. Although there are distinct gross anatomical differences in the appearance of this organ between "lower" mammals such as rodents and lagomorphs and "higher" mammals such as carnivores and primates, its fine structure is remarkably similar in all species studied. There are many suggestions in the literature for a specific function for this area of the brain, ranging from its being a chemoreceptive trigger zone for the emetic response to its being a regulatory nucleus for the sleep cycle. The present report describes some comparative studies on the ultrastructure of this organ. This information is discussed in relation to what is known about the neurochemistry of the area postrema and its connections with other brain regions and visceral structures. A suggestion is offered that our current knowledge of the area postrema is consistent with its performing many of its proposed functions in the context of a regulatory ("fine-tuning") center for many autonomic functions.  相似文献   

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