首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 0 毫秒
1.
Exposure to sublethal heat stress activates a complex cascade of signaling events, such as activators (NO), signal molecules (PKCε), and mediators (HSP70 and COX-2), leading to implementation of heat preconditioning, an adaptive mechanism which makes the organism more tolerant to additional stress. We investigated the time frame in which these chemical signals are triggered after heat stress (41?±?0.5°С/45 min), single or repeated (24 or 72 h after the first one) in heart tissue of male Wistar rats. The animals were allowed to recover 24, 48 or 72 h at room temperature. Single heat stress caused a significant increase of the concentration of HSP70, NO, and PKC level and decrease of COX-2 level 24 h after the heat stress, which in the next course of recovery gradually normalized. The second heat stress, 24 h after the first one, caused a significant reduction of the HSP70 levels, concentration of NO and PKC?, and significant increase of COX-2 concentration. The second exposure, 72 h after the first heat stress, caused more expressive changes of HSP70 and NO in the 24 h-recovery groups. The level of PKC? was not significantly changed, but there was significantly increased COX-2 concentration during recovery. Serum activity of AST, ALT, and CK was reduced after single exposure and increased after repeated exposure to heat stress, in both time intervals. In conclusion, a longer period of recovery (72 h) between two consecutive sessions of heat stress is necessary to achieve more expressive changes in mediators (HSP70) and triggers (NO) of heat preconditioning.  相似文献   

2.
Over the past 25 years, new techniques, new discoveries, and new ideas have profoundly impacted our understanding of deuterostome interrelationships and, ultimately, deuterostome evolution. During the late 1980s and early 1990s morphological cladistic analyses made predictions about both taxonomic history and homology, predictions that would be tested independent of the morphological characters themselves with the advent of molecular systematics, the rise of evolutionary developmental biology, and continued exploration of the fossil record. Thanks to these three areas of inquiry, we have gone from scenarios where animals like mobile enteropneust hemichordates and chordates were derived from sessile filter-feeding animals like modern lophophorates, echinoderms, and pterobranch hemichordates, to a new perspective where hemichordates are recognized as the nearest living relative of the echinoderms, and that vagile gill-bearing animals like Cambrian vetulicolians are seen—at least by some—as close to the deuterostome last common ancestor, with both sessility and filter-feeding convergent features of deuterostomes (e.g., echinoderm) and non-deuterostomes (e.g., lophophorates) alike. Although much of the backbone of the new deuterostome phylogeny is supported by multiple independent data sets, as are statements of homology of several different morphological characters, in particular the homology of gill slits across Deuterostomia, nonetheless, the next quarter century of study on this remarkable group of animals promises to be as equally illuminating and exciting as the past quarter century.  相似文献   

3.
4.
Transglutaminase is an enzyme able to play more than one enzymatic action, acting on a variety of different substrates. The growth of knowledge about the members of the enzyme transglutaminase’s family and its substrates since the last 50 years indicates a large interest and curiosity about this protein, whose function and structure was, but still is, an important object of research. On the other hand, the involvement in a number of human diseases together with the lack of knowledge about the biological functions played by some of the most studied members of this family, make this enzyme a fascinating field of study. The history of this enzyme and its substrates, whose cross-linking action was reported for the first time 50 years ago, suggests that an effort to increase knowledge and communication among researchers is required. To achieve this important result, 10 years ago an internet web page called worldwide happening around transglutaminase (WHAT) was created. Driven by these experiences, novel points-of-view to look at Transglutaminase and its substrates may be identified.  相似文献   

5.
Approximately 20 years ago, Avise and colleagues proposed the integration of phylogenetics and population genetics for investigating the connection between micro- and macroevolutionary phenomena. The new field was termed phylogeography. Since the naming of the field, the statistical rigor of phylogeography has increased, in large part due to concurrent advances in coalescent theory which enabled model-based parameter estimation and hypothesis testing. The next phase will involve phylogeography increasingly becoming the integrative and comparative multi-taxon endeavor that it was originally conceived to be. This exciting convergence will likely involve combining spatially-explicit multiple taxon coalescent models, genomic studies of natural selection, ecological niche modeling, studies of ecological speciation, community assembly and functional trait evolution. This ambitious synthesis will allow us to determine the causal links between geography, climate change, ecological interactions and the evolution and composition of taxa across whole communities and assemblages. Although such integration presents analytical and computational challenges that will only be intensified by the growth of genomic data in non-model taxa, the rapid development of “likelihood-free” approximate Bayesian methods should permit parameter estimation and hypotheses testing using complex evolutionary demographic models and genomic phylogeographic data. We first review the conceptual beginnings of phylogeography and its accomplishments and then illustrate how it evolved into a statistically rigorous enterprise with the concurrent rise of coalescent theory. Subsequently, we discuss ways in which model-based phylogeography can interface with various subfields to become one of the most integrative fields in all of ecology and evolutionary biology.  相似文献   

6.
A species of xanthopygine rove beetles is described and figured here as Darwinilus sedarisigen. n. and sp. n. The holotype was collected by Charles Darwin in Bahía Blanca, Argentina on the Beagle’s voyage. The contributions of Charles Darwin to rove beetle systematics are summarized briefly.  相似文献   

7.
In the present essay, I first recall the genealogical concept of classification settled by Charles Darwin in the Origin of Species. Darwin tightly linked what we now call phylogeny and development. He often insisted to take into account embryonic and larval characters, most often using as examples his favourite animals, the cirripedes. Then I discuss remaining problems, and also perspectives, to address the link between phylogeny and development in the modern terms of molecular and cladistic phylogenetics and of molecular and genetic developmental biology.  相似文献   

8.
Mala JG  Rose C 《Life sciences》2010,87(19-22):579-586
Heat shock proteins (HSPs) are upregulated and manifested upon cellular stress and possess chaperoning functions. HSP47 is an endoplasmic reticulum (ER)-resident, collagen-specific chaperone and plays a key role in collagen biosynthesis and its structural assembly. The collagen scaffold is a primary structural target of recent interest due to its applications in tissue engineering and drug delivery and in treatment of clinical disorders. This review highlights the fundamental aspects of HSPs in protein folding and quality control, in the elicitation of a stress response in connective tissue and in the characterization of HSP47 in collagen folding and assembly. The significant features of HSP47 which are distinct in its cellular capabilities are discussed. We propose that targeting the stress response is a key factor in identifying connective tissue biomarkers. We also address the issues and strategies involved in the stress response of connective tissue diseases. In conclusion, we describe the prospects of collagen biochemistry in correlation to the science of HSPs.  相似文献   

9.
The inappropriate genetic expansion of various repetitive DNA sequences underlies over 20 distinct inherited diseases. The genetic context of these repeats in exons, introns and untranslated regions has played a major role in thinking about the mechanisms by which various repeat expansions might cause disease. Repeat expansions in exons are thought to give rise to expanded toxic protein repeats (i.e. polyQ). Repeat expansions in introns and UTRs (i.e. FXTAS) are thought to produce aberrant repeat-bearing RNAs that interact with and sequester a wide variety of essential proteins, resulting in cellular toxicity. However, a new phenomenon termed ‘repeat-associated nonAUG dependent (RAN) translation’ paints a new and unifying picture of how distinct repeat expansion-bearing RNAs might act as substrates for this noncanonical form of translation, leading to the production of a wide range of repeat sequence-specific-encoded toxic proteins. Here, we review how the model system Caenorhabditis elegans has been utilized to model many repeat disorders and discuss how RAN translation could be a previously unappreciated contributor to the toxicity associated with these different models.  相似文献   

10.
Due to its public popularity, ornithology has a huge corpus of scientific publication for a relatively small number of species. Although there are global checklists of currently recognised taxa, there has been only limited, mainly individual, effort to build a nomenclatural database that the science of ornithology deserves. This is especially true in relation to concise synonymies. With the arrival of ZooBank and the Biodiversity Heritage Library, the time has come to develop synonymies and to add fuller bibliographic detail to databases. The preparation for both began at the start of the 20th century with extensive work by Sherborn and Richmond. I discuss their legacy, offer notes on significant work since then, and provide suggestions for what remains to be done. To make solid the foundations for ornithological nomenclature and taxonomy, especially for synonymies, ornithologists will need to collaborate much more and contribute to the digital infrastructure.  相似文献   

11.
12.
13.
Biotechnological and life science innovations do not only lead to immense progress in diverse fields of natural science and technical research and thereby drive economic development, they also fundamentally affect the relationship between nature, technology and society. Taken this seriously, the ethical and societal assessment of emerging biotechnologies as for example synthetic biology is challenged not only to constrain on questions of biosafety and biosecurity but also to face the societal questions within the different fields as an interface problem of science and society. In order to map this vague and stirring field, we propose the concept of bio-objects to explore the reciprocal interaction at the interface of science and society serious as well to have the opportunity to detect possible junctions of societal discontent and unease before their appearance.  相似文献   

14.
Darwin’s main contribution to modern biology was to make clear that all history of life on earth is dominated by a simple principle, which is usually summarised as 'descent with modification'. However, interpretations about how this modification is produced have been controversial. In light of the data provided by recent studies on molecular biology, developmental biology, genomics, and other biological disciplines we discuss, in this paper, how Darwin's theory may apply to two main 'types' of evolution: that occurring in the prebiotic world and that regarding the acquisition of major key-innovations differentiating higher-taxa, which makes up part of the so-called macroevolution. We argue that these studies show that evolution is a fascinating, complex and multifaceted process, with different mechanisms drivin it on different occasions and in different places.  相似文献   

15.
The debate about the levels of selection has been one of the most controversial both in evolutionary biology and in philosophy of science. Okasha’s book makes the sort of contribution that simply will not be able to be ignored by anyone interested in this field for many years to come. However, my interest here is in highlighting some examples of how Okasha goes about discussing his material to suggest that his book is part of an increasingly interesting trend that sees scientists and philosophers coming together to build a broadened concept of “theory” through a combination of standard mathematical treatments and conceptual analyses. Given the often contentious history of the relationship between philosophy and science, such trend cannot but be welcome.  相似文献   

16.
17.
Many questions regarding evolution and ontogeny of the insect head remain open. Likewise, the genetic basis of insect head development is poorly understood. Recently, the investigation of gene expression data and the analysis of patterning gene function have revived interest in insect head development. Here, we argue that the red flour beetle Tribolium castaneum is a well suited model organism to spearhead research with respect to the genetic control of insect head development. We review recent molecular data and discuss its bearing on early development and morphogenesis of the head. We present a novel hypothesis on the ontogenetic origin of insect head sutures and review recent insights into the question on the origin of the labrum. Further, we argue that the study of developmental genes may identify the elusive anterior non-segmental region and present some evidence in favor of its existence. With respect to the question of evolution of patterning we show that the head Anlagen of the fruit fly Drosophila melanogaster and Tribolium differ considerably and we review profound differences of their genetic regulation. Finally, we discuss which insect model species might help us to answer the open questions concerning the genetic regulation of head development and its evolution.  相似文献   

18.
19.
20.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号