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排序方式: 共有1612条查询结果,搜索用时 31 毫秒
131.
Kevin M. Ringelman Christopher K. Williams Patrick K. Devers John M. Coluccy Paul M. Castelli Kurt A. Anderson Jacob L. Bowman Gary R. Costanzo Dane M. Cramer Matt T. Dibona Michael W. Eichholz Min Huang Benjamin Lewis Jr. Dawn M. Plattner Tina Yerkes 《The Journal of wildlife management》2015,79(8):1298-1307
132.
Simplified method for the collection, storage, and comet assay analysis of DNA damage in whole blood
Al-Salmani K Abbas HH Schulpen S Karbaschi M Abdalla I Bowman KJ So KK Evans MD Jones GD Godschalk RW Cooke MS 《Free radical biology & medicine》2011,51(3):719-725
Single-cell gel electrophoresis (comet assay) is one of the most common methods used to measure oxidatively damaged DNA in peripheral blood mononuclear cells (PBMC), as a biomarker of oxidative stress in vivo. However, storage, extraction, and assay workup of blood samples are associated with a risk of artifactual formation of damage. Previous reports using this approach to study DNA damage in PBMC have, for the most part, required the isolation of PBMC before immediate analysis or freezing in cryopreservative. This is very time-consuming and a significant drain on human resources. Here, we report the successful storage of whole blood in ~ 250 μl volumes, at − 80 °C, without cryopreservative, for up to 1 month without artifactual formation of DNA damage. Furthermore, this blood is amenable for direct use in both the alkaline and the enzyme-modified comet assay, without the need for prior isolation of PBMC. In contrast, storage of larger volumes (e.g., 5 ml) of whole blood leads to an increase in damage with longer term storage even at − 80 °C, unless a cryopreservative is present. Our “small volume” approach may be suitable for archived blood samples, facilitating analysis of biobanks when prior isolation of PBMC has not been performed. 相似文献
133.
Bowman JL 《Current biology : CB》2011,21(14):R540-R541
Two studies suggest early land plants could actively control stomata, facilitating gas exchange while limiting water loss, a critical adaption to life on land. 相似文献
134.
Levy MZ Small DS Vilhena DA Bowman NM Kawai V Cornejo del Carpio JG Cordova-Benzaquen E Gilman RH Bern C Plotkin JB 《PLoS computational biology》2011,7(9):e1002146
Vector-borne transmission of Chagas disease has become an urban problem in the city of Arequipa, Peru, yet the debilitating symptoms that can occur in the chronic stage of the disease are rarely seen in hospitals in the city. The lack of obvious clinical disease in Arequipa has led to speculation that the local strain of the etiologic agent, Trypanosoma cruzi, has low chronic pathogenicity. The long asymptomatic period of Chagas disease leads us to an alternative hypothesis for the absence of clinical cases in Arequipa: transmission in the city may be so recent that most infected individuals have yet to progress to late stage disease. Here we describe a new method, epicenter regression, that allows us to infer the spatial and temporal history of disease transmission from a snapshot of a population's infection status. We show that in a community of Arequipa, transmission of T. cruzi by the insect vector Triatoma infestans occurred as a series of focal micro-epidemics, the oldest of which began only around 20 years ago. These micro-epidemics infected nearly 5% of the community before transmission of the parasite was disrupted through insecticide application in 2004. Most extant human infections in our study community arose over a brief period of time immediately prior to vector control. According to our findings, the symptoms of chronic Chagas disease are expected to be absent, even if the strain is pathogenic in the chronic phase of disease, given the long asymptomatic period of the disease and short history of intense transmission. Traducción al espa?ol disponible en Alternative Language Text S1/A Spanish translation of this article is available in Alternative Language Text S1. 相似文献
135.
LaRonda L. Morford Christopher J. Bowman Diann L. Blanset Ingrid B. Bøgh Gary J. Chellman Wendy G. Halpern Gerhard F. Weinbauer Timothy P. Coogan 《Birth defects research. Part B, Developmental and reproductive toxicology》2011,92(4):359-380
Evaluation of pharmaceutical agents in children is now conducted earlier in the drug development process. An important consideration for this pediatric use is how to assess and support its safety. This article is a collaborative effort of industry toxicologists to review strategies, challenges, and current practice regarding preclinical safety evaluations supporting pediatric drug development with biopharmaceuticals. Biopharmaceuticals include a diverse group of molecular, cell‐based or gene therapeutics derived from biological sources or complex biotechnological processes. The principles of preclinical support of pediatric drug development for biopharmaceuticals are similar to those for small molecule pharmaceuticals and in general follow the same regulatory guidances outlined by the Food and Drug Administration and European Medicines Agency. However, many biopharmaceuticals are also inherently different, with limited species specificity or immunogenic potential which may impact the approach taken. This article discusses several key areas to aid in the support of pediatric clinical use, study design considerations for juvenile toxicity studies when they are needed, and current practices to support pediatric drug development based on surveys specifically targeting biopharmaceutical development. Birth Defects Res (Part B) 92:359–380, 2011. © 2011 Wiley‐Liss, Inc. 相似文献
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137.
Riquelme M Yarden O Bartnicki-Garcia S Bowman B Castro-Longoria E Free SJ Fleissner A Freitag M Lew RR Mouriño-Pérez R Plamann M Rasmussen C Richthammer C Roberson RW Sanchez-Leon E Seiler S Watters MK 《Fungal biology》2011,115(6):446-474
Neurospora crassa has been at the forefront of biological research from the early days of biochemical genetics to current progress being made in understanding gene and genetic network function. Here, we discuss recent developments in analysis of the fundamental form of fungal growth, development and proliferation -- the hypha. Understanding the establishment and maintenance of polarity, hyphal elongation, septation, branching and differentiation are at the core of current research. The advances in the identification and functional dissection of regulatory as well as structural components of the hypha provide an expanding basis for elucidation of fundamental attributes of the fungal cell. The availability and continuous development of various molecular and microscopic tools, as utilized by an active and co-supportive research community, promises to yield additional important new discoveries on the biology of fungi. 相似文献
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140.
Aim Numerous studies have examined the climatic factors that influence the abundance of C4 species within the grass flora (C4 relative species richness) in various regions throughout the world, but very few have examined the relative abundance of C4 vs. C3 grasses (C4 relative abundance). We sought to determine the climatic factors that influence C4 relative abundance throughout Australia. Location Australia (including Tasmania). Methods We measured C4 relative abundance at 168 locations and measured δ13C (the abundance of 13C relative to 12C) of the bone collagen of 779 kangaroos collected throughout Australia, as bone collagen δ13C was assumed to be proportional to the relative abundance of C4 grasses in the diet. Results Both C4 relative abundance and kangaroo bone collagen δ13C were found to have a strong positive relationship with seasonal water availability, i.e. the distribution of rainfall in the C4 vs. C3 growing seasons (76% and 69% of deviance explained, respectively). There was clear evidence that seasonal water availability was a better predictor of both C4 relative abundance and bone collagen δ13C than other climate variables such as mean annual temperature and January daily minimum temperature. However, seasonal water availability appeared to be a relatively poor predictor of C4 relative species richness, which was most closely related to January daily minimum temperature (90% of deviance explained). Main conclusions Our results highlight the relatively poor relationship between C4 relative abundance and C4 relative species richness, and suggest that these two variables may be related to different climatic factors. They also suggest that caution is required when using C4 relative species richness to infer the relative biomass and productivity of C4 grasses on a global scale. 相似文献