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1.
Actin is an abundant protein in most nonmuscle cells. It has often been observed in isolated nuclei, yet cytoplasmic contamination was of course initially regarded as the most plausible origin. Numerous studies on nuclear actin appeared in the 1970s and 1980s, but the picture remained rather muddy. The viewpoint at that time was that actin-shown to move freely between cytoplasm and nucleus-was a mere "thermodynamic wanderer," transiently occupying the nucleus. More recently, evidence has been mounting that actin's presence in the nucleus is not simply governed by the laws of diffusion. The same holds true for the finding of various actin-related proteins in the nucleus, and the case for nuclear myosin, specifically myosin I, is now quite convincing. Moreover, the first intimations of functional roles of nuclear actin are now emerging. Here we examine the overall subject from cell biological and chemical perspectives. The major issue is no longer the presence of actin in the nucleus but rather its supramolecular organization, intranuclear locations, and, of course, functions. These issues interface with recent findings that reveal a surprisingly diverse repertoire of actin conformations and oligomer and polymer forms beyond monomeric G-actin and polymeric F-actin. We present ideas for advancing the nuclear actin field and call for a renewed attack on this major problem in cell biology.  相似文献   

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The present review underlines the knowledge of Cryptosporidium, especially its biodiversity and transmission. The presence of the parasite in different mammal host species is discussed with real, potential risk of transmission to humans. The potential role of insects in mechanical transmission of the parasite is evaluated by experimental protocols. The cost of cryptosporidiosis at health and economic levels are mentioned, which emphasises the importance of detection and identification of the parasite in the environment and in wild mammal species, using specific molecular tools. Potential measures to be accomplished in order to fight off cryptosporidiosis are also noted.  相似文献   

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Traditional plant use is of tremendous importance in many societies, including most rural African communities. A variety of studies have shown knowledge dwindling due to changes towards a more Western lifestyle, and the influence of modern tourism. In the case of the Sekenani Maasai, we hypothesized in 2006 that, while little knowledge loss had been observed at that time, the change from a nomadic to a more sedentary lifestyle would lead to an accelerating loss of traditional plant knowledge. This paper examines the plant use of the Maasai in the Sekenani Valley, North of the Maasai Mara National Reserve 15 years after a first study. Based on the study of 2002 (Bussmann et al. Journal of Ethnobiology and Ethnomedicine 2: 22, 2006), semi-structured interviews were conducted with staff of Sekenani Camp in order to document current plant knowledge. The results of this follow-up study indicate dramatic knowledge loss over the last 15 years. Of 139 used species documented in 2002, only 84 remained in use in 2017. Off those species still in use, 30 had experienced a loss of uses, while for 18 species new uses were documented. The knowledge loss observed in Sekenani in 15 years is rather dramatic. Lifestyle changes and over-use of resources have clearly led to a rapid decline of traditional knowledge on plant use. This trend is expected to continue.  相似文献   

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Predation on livestock is a cause of serious and long-lasting conflict between farmers and wildlife, promoting negative public attitudes and endangering conservation of large carnivores. However, while large carnivores, especially the grey wolf (Canis lupus), are often blamed for killing sheep and other farm animals, free-ranging dogs may also act as predators. To develop appropriate measures for livestock protection, reliable methods for identifying predator species are critical. Identification of predators from visual examination of livestock wounds can be ambiguous and genetic analysis is strongly preferable for accurate species determination. To estimate the proportion of wolves and dogs implicated in sheep predation, we developed a sensitive genetic assay to distinguish between wolves and domestic dogs. A total of 183 predator saliva samples collected from killed sheep in Estonia were analysed. The assay identified the predator species in 143 cases (78%). Sheep were most often killed by wolves (81%); however, predation by dogs was substantial (15%). We compared the molecular results with field observations conducted by local environmental officials and recorded some disagreement, with the latter underestimating the role of dogs. As predator saliva samples collected from prey are often of poor quality, we suggest using mitochondrial DNA as a primary tool to maximise the number of successfully analysed samples. We also suggest adopting forensic DNA analysis more widely in livestock predation assessments as a legislative measure since misidentification that is biased against wolves can be counterproductive for conservation by enhancing conflict with society and leading to increased culling and poaching.  相似文献   

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Quality assurance of recombinant protein drugs concerning identity and purity represents a difficult task, in particular, when post-translational modifications lead to a heterogeneous mixture of biomolecules. We chose Neorecormon (rh-EPO, Roche) for our studies to demonstrate the efficiency of two-dimensional electrophoresis (2-DE) to analyse post-translationally modified recombinant drugs. More than 40 protein spots in the range from isoelectric point (pI) 3.5-4.5 and 32-45 kDa could be separated. Enzymatic deglycosylation revealed that the heterogeneity of the protein pattern is mainly caused by variations in glycosylation. In comparison to the separately performed isoelectric focusing and sodium dodecyl sulfate-polyacrylamide gel electrophoresis, as requested by the European Pharmacopoeia, we see a great synergy to use 2-DE for the analysis of rh-EPO. A by far higher resolution can be achieved, allowing an improved differentiation of the various rh-EPO glycoforms. Sequential deglycosylation of sialic acids, N-glycosides and the O-glycoside lead to significant shifts both in apparent relative molecular mass and pI. Comparing the 2-DE patterns of rh-EPO before and after deglycosylation allows on the one hand valuable information to be gained on the glycosylation of the recombinant protein and shows on the other hand how significantly the 2-DE protein pattern can be influenced by the glycosylation. As the equipment for the performance of 2-DE has improved significantly over the last decade, we see 2-DE as a reliable method, which should be approved for the routine quality assurance of recombinant drugs and also recommended for the European Pharmacopoeia.  相似文献   

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The African trypanosomes remain well recognised for their role as an interesting model eukaryote for basic science, but are loosing ground in their ability to contribute to understanding common cellular mechanisms. At the same time, the diseases they cause remain as prevalent as ever, but appear increasingly irrelevant in their wider medical, social, economic and political context. What can be done to keep trypanosome biology relevant and vigorous in the 21st century?  相似文献   

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Does gene testing indicate a switch from an histopathological to a molecular approach of human diseases ? Disease management in oncology is already improved by gene testing, at least for some specific cancers. It is however necessary to distinguish the analysis of genes specific to the tumour which gives clues about the fate of the tumours, from those unique to the patients, which gives clues about the future of the person. For the latter so-called germline mutations, wide scale gene-default screening would put pressure on resource allocation from the health care systems of developed countries. Currently the cost of detecting of 700 genes in the whole French population would exceed the whole health budget of the country for the next 10 years. Even if we can anticipate a dramatic decrease in the unit cost of these genetic tests in the future, their diffusion should not be controlled exclusively by technological and market forces. In this paper, we propose to discuss four main parameters for regulating these genetic tests, using as an archetypal example their application to cancer prevention and treatment: (1) which specific cancer disease is targeted by the test (prevalence, incidence, likelihood of cure with current therapeutics, number of years of life potentially saved...); (2) what are the characteristics of the genes tested and which level of evidence is required about the predictive value of the test; (3) what are the size and characteristics of the population who will be offered the test, and (4) which process and public control are necessary before market approval of the test and reimbursement of related expenditures by health care insurance schemes.  相似文献   

11.
Fascin is a globular actin cross-linking protein that has a major function in forming parallel actin bundles in cell protrusions that are key specialisations of the plasma membrane for environmental guidance and cell migration. Fascin is widely expressed in mesenchymal tissues and the nervous system and is low or absent in adult epithelia. Recent data from a number of laboratories have highlighted that fascin is up-regulated in many human carcinomas and, in individual tissues, correlates with the clinical aggressiveness of tumours and poor patient survival. In cell culture, over-expression or depletion of fascin modulates cell migration and alters cytoskeletal organisation. The identification of biomarkers to provide more effective early diagnosis of potentially aggressive tumours, or identify tumours susceptible to targeted therapies, is an important goal in clinical research. Here, we discuss the evidence that fascin is upregulated in carcinomas, its contributions to carcinoma cell behaviour and its potential as a candidate novel biomarker or therapeutic target.  相似文献   

12.
Gay JM 《Theriogenology》2006,66(3):526-533
The concepts and methods of the different branches of epidemiology, particularly clinical epidemiology, have much to offer the discipline of theriogenology. As with theriogenology, epidemiologic methods evolve when technological innovation enables new approaches to old problems. The recent emergence, from clinical epidemiology, of the evidence-based medicine paradigm in human medicine, and the associated developments of systematic reviews and meta-analysis, present new opportunities for collaboration and synergy between the two disciplines.  相似文献   

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The Millennium Ecosystem Assessment and other commentators have warned about the impacts that biodiversity decline will have on human health. There is no doubting that the natural world provides mankind with the majority of the resources required to sustain life and health. Many species provide food, fuel, medicines; with the potential for many more (as of yet) undiscovered uses for various species. Despite this, there have been very few attempts to actually investigate relationships between biodiversity (i.e. number of species, rather than the ability of specific species to provide health benefits) and human health. This paper reviews the available evidence and demonstrates that while the links between biodiversity and health seem intuitive, they are very difficult to prove. Socio-economics has a huge influence on health status and the exploitation of natural resources (leading to eventual biodiversity loss) tends to have a positive economic effects. More direct effects of biodiversity on health include the diversity of the internal microbiome, the effect of natural diversity on our mental health and well-being (although this has large social aspects with many people feeling fearful in very diverse environments). Still to be elucidated are the tipping points where the level of global biodiversity loss is such that human health can no longer be sustained.  相似文献   

16.
Wildlife monitoring performed by volunteer personnel may suffer from bias with regard to their habitat use. Such errors can lead to erroneous population estimates, evidently influencing both management programmes and research that are based on the monitoring. We used a dataset on hunters’ habitat use in forest while searching for black grouse (Tetrao tetrix) and capercaillie (Tetrao urogallus) to test whether hunters’ utilisation of the habitat was independent of that of grouse or if it corresponded to the grouse habitat preference. Twenty volunteer hunters with dogs registered their tracks and all observations of capercaillie and black grouse in Østfold County, Norway, during August 2003 and 2004. We performed an ecological niche factor analysis (ENFA) and a K-select analysis with respect to hunters’ selection for habitat, described with ecogeographical variables related to forest stand characteristics, as well as the habitat preference of the observed grouse, conditional on the habitat utilisation of the hunters. Individual ENFA on the hunter's tracks revealed large variation in the habitat preferences of the hunters. The K-select indicated few overall patterns in the habitat characteristics of grouse observations, conditional on the hunters selected habitat. Accordingly, the results indicate that hunters’ observation of grouse prior to the hunt may give indicators of changes in grouse density unbiased by habitat preference due to the large between-hunter variation in habitat preference, given that a sufficient number of hunters is used. This suggests that such monitoring programmes can provide information about fluctuations in grouse population sizes valuable for both the management and research of forest grouse species.  相似文献   

17.
The impressive performance of the research in mitochondrial genetics and human aging in the last decade outlines a new scenery in which the inherited variation of the mitochondrial genome (mtDNA) may play a role in rate and quality of aging. This variation in humans was initially looked at as nearly neutral, and useful just for the reconstruction of human population history. However, recent data suggest that different mtDNA molecules are qualitatively different from each other. The aim of this paper is to discuss current ideas on the relationships among mitochondrial function, mtDNA inherited variation, and aging. The main processes where the mitochondrion is involved and the importance these processes have on aging and death of individuals will be described. A possible connection between programmed death phenomena (mitoptosis, apoptosis, phenoptosis) and rate and quality of aging will be discussed. Finally, the possible role played in these processes by the mtDNA germline variation will be explored.  相似文献   

18.
Extreme climate, especially temperature, can severely reduce wheat yield. As global warming has already begun to increase mean temperature and the occurrence of extreme temperatures, it has become urgent to accelerate the 5–20 year process of breeding for new wheat varieties, to adapt to future climate. We analyzed the patterns of frost and heat events across the Australian wheatbelt based on 50 years of historical records (1960–2009) for 2864 weather stations. Flowering dates of three contrasting‐maturity wheat varieties were simulated for a wide range of sowing dates in 22 locations for ‘current’ climate (1960–2009) and eight future scenarios (high and low CO2 emission, dry and wet precipitation scenarios, in 2030 and 2050). The results highlighted the substantial spatial variability of frost and heat events across the Australian wheatbelt in current and future climates. As both ‘last frost’ and ‘first heat’ events would occur earlier in the season, the ‘target’ sowing and flowering windows (defined as risk less than 10% for frost (<0 °C) and less than 30% for heat (>35 °C) around flowering) would be shifted earlier by up to 2 and 1 month(s), respectively, in 2050. A short‐season variety would require a shift in target sowing window 2‐fold greater than long‐ and medium‐season varieties by 2050 (8 vs. 4 days on average across locations and scenarios, respectively), but would suffer a lesser decrease in the length of the vegetative period (4 vs. 7 days). Overall, warmer winters would shorten the wheat season by up to 6 weeks, especially during preflowering. This faster crop cycle is associated with a reduced time for resource acquisition, and potential yield loss. As far as favourable rain and modern equipment would allow, early sowing and longer season varieties (i.e. in current climate) would be the best strategies to adapt to future climates.  相似文献   

19.
The global database of invasive trees and shrubs has been updated, resulting in a total of 751 species (434 trees and 317 shrubs) from 90 families (Rejmánek and Richardson 2013 Divers Distrib 19:1093–1094). This database is used to assess major trends in human-assisted exchanges of dendrofloras among 15 major geographical regions. Areas most invaded by non-native trees are Pacific Islands (136 species), Southern Africa (118), Australia (116), and North America (114). Areas most invaded by non-native shrubs are North America (98), Australia (87), Pacific Islands (71), and Europe (61). The most important sources of invasive trees are Asia (122–146 species, depending on how many Eurasian species are considered to have been introduced only from Europe), Australia (81), and South America (81). The most important sources of invasive shrubs are Asia (103–118), Europe (68), and South America (54). Mean number of native geographical regions for invasive trees is 1.64, while the mean number of invaded regions by trees is 2.51. The difference is smaller for shrubs: 1.60 versus 2.11. Asia is the major source of invasive Rosaceae shrubs, as well as invasive Arecaceae and Oleaceae species. South America and Australia are major sources of invasive Fabaceae trees. North America and Europe are major sources of invasive Pinaceae. Most of the invasive Salicaceae are of Eurasian origin. The identified trends will very likely continue in this century. Because of increasing interactions with many states in Asia, even more invasive woody species will be introduced from this part of the world.  相似文献   

20.
The urgency of the tropical biodiversity crisis continues to be a major justification for wildlife research and its funding. To examine the benefits of this research for on-the-ground conservation, we focused on Borneo, where conservation has a long history and we have direct experience. We compiled, categorized and evaluated 284 publications from a broad variety of sources, 153 from peer-reviewed journals. We found that few studies address threats to species and fewer still provide input for or guidance to effective management. We consider various reasons for these shortcomings. Research is seldom judged on its relevance to pragmatic problem solving. Furthermore, many research programs lack the necessary long-term vision and organizational structure for useful applied research. We consulted conservation leaders about our conclusions and all responses suggest that our concerns are not unique to Borneo but reflect wider problems. We conclude that conservation research across most of the tropics is failing to address conservation needs. We make a number of recommendations based on our findings. Conservation biologists should place a higher priority on addressing practical conservation needs and goals.  相似文献   

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