Home About us Contact
|
Home About us Contact | ||
|
|
||
Basic Biology (basic + biology)
Selected AbstractsWhy does Candida albicans switch?FEMS YEAST RESEARCH, Issue 7 2009David R. Soll Abstract White,opaque switching in Candida albicans was first discovered in 1987. Fifteen years later, and three years after the discovery of the mating system, it was demonstrated that the switch from white to opaque was an essential step in the mating process. But this latter discovery did not reveal why C. albicans had this requirement, when Saccharomyces cerevisiae and other hemiascomycetes did not. The discovery that mating-competent opaque cells signaled mating-incompetent white cells, through the release of pheromones, to become adhesive and form biofilms provided a clue to this fundamental question. Opaque cells appeared to signal white cells to form biofilms that facilitated mating by protecting the fragile gradients of the pheromone that directed chemotropism, a process necessary for fusion. Here, we explore the discoveries and observations that have led to this hypothesis, and the ancillary questions that have risen that are related to the regulation of the unique pheromone response, the evolution of this response and the relationship between pheromone-enhanced white cell biofilms and ,asexual' biofilms formed by a/, cells. This discussion, therefore, focuses on a unique and complex component of the basic biology of C. albicans that relates switching, mating and pathogenesis. [source] Behavioral phenotyping enhanced , beyond (environmental) standardizationGENES, BRAIN AND BEHAVIOR, Issue 1 2002H. Würbel It is basic biology that the phenotype of an animal is the product of a complex and dynamic interplay between nature (genotype) and nurture (environment). It is far less clear, however, how this might translate into experimental design and the interpretation of animal experiments. Animal experiments are a compromise between modelling real world phenomena with maximal validity (complexity) and designing practicable research projects (abstraction). Textbooks on laboratory animal science generally favour abstraction over complexity. Depending on the area of research, however, abstraction can seriously compromise information gain, with respect to the real world phenomena an experiment is designed to model. Behavioral phenotyping of mouse mutants often deals with particularly complex manifestations of life, such as learning, memory or anxiety, that are strongly modulated by environmental factors. A growing body of evidence indicates that current approaches to behavioral phenotyping might often produce results that are idiosyncratic to the study in which they were obtained, because the interactive nature of genotype-environment relationships underlying behavioral phenotypes was not taken into account. This paper argues that systematic variation of genetic and environmental backgrounds, instead of excessive standardization, is needed to control the robustness of the results and to detect biologically relevant interactions between the mutation and the genetic and environmental background of the animals. [source] Nocturnal swimming, aggregation at light traps, and mass spawning of scissurellid gastropods (Mollusca: Vetigastropoda)INVERTEBRATE BIOLOGY, Issue 1 2007Carole S. Hickman Abstract. Thousands of minute scissurellid gastropods (Vetigastropoda: Scissurellidae) were observed and collected at floating light traps in Moorea, French Polynesia, where a mass spawning event occurred on November 11, 2002. More than 20,000 live snails were recovered from the traps, and epidemic spawning continued in the laboratory, where clouds of white sperm and red-orange eggs were broadcast into the water. No aggregations of this magnitude have been reported previously in vetigastropods, nor is the capacity for sustained swimming known from other vetigastropod taxa. Snails had emerged from a local benthic habitat of coral sand and swum through ,2 m of water to reach the traps. Scanning electron micrographs of the ornate shells confirm the identity of the most abundant species as Scissurella spinosa, with lesser numbers of Sinezona plicata. Our observations indicate that scissurellids are not exclusively benthic and that they are not rare, even though they have seldom been collected and studied alive. Because little is known about the basic biology and anatomy of scissurellids and because their position within the basal Gastropoda is poorly resolved, we include information on the design and construction of inexpensive light traps to promote comparative investigation of other poorly known species. [source] Is iPS cell the panacea?IUBMB LIFE, Issue 3 2010Li Ou Abstract In 2006, it was reported that transgenic expression of merely four defined transcription factors (c-Myc, Klf4, Oct4, and Sox2) is sufficient to reprogram somatic cells to a pluripotent state. The resulting induced pluripotent stem (iPS) cells ignited intense interest in the field of life science for their promising applications in basic biology, drug development, and transplantation. However, the underlying problems of iPS cells seem to be ignored. This review shed light on the problems pertaining iPS cells, including the elusive origin, risk of tumorgenesis, and its relationship with natural selection. © 2010 IUBMB IUBMB Life, 62(3): 170,175, 2010 [source] Darkness visible: reflections on underground ecologyJOURNAL OF ECOLOGY, Issue 2 2005A. H. FITTER Summary 1Soil science and ecology have developed independently, making it difficult for ecologists to contribute to urgent current debates on the destruction of the global soil resource and its key role in the global carbon cycle. Soils are believed to be exceptionally biodiverse parts of ecosystems, a view confirmed by recent data from the UK Soil Biodiversity Programme at Sourhope, Scotland, where high diversity was a characteristic of small organisms, but not of larger ones. Explaining this difference requires knowledge that we currently lack about the basic biology and biogeography of micro-organisms. 2It seems inherently plausible that the high levels of biological diversity in soil play some part in determining the ability of soils to undertake ecosystem-level processes, such as carbon and mineral cycling. However, we lack conceptual models to address this issue, and debate about the role of biodiversity in ecosystem processes has centred around the concept of functional redundancy, and has consequently been largely semantic. More precise construction of our experimental questions is needed to advance understanding. 3These issues are well illustrated by the fungi that form arbuscular mycorrhizas, the Glomeromycota. This ancient symbiosis of plants and fungi is responsible for phosphate uptake in most land plants, and the phylum is generally held to be species-poor and non-specific, with most members readily colonizing any plant species. Molecular techniques have shown both those assumptions to be unsafe, raising questions about what factors have promoted diversification in these fungi. One source of this genetic diversity may be functional diversity. 4Specificity of the mycorrhizal interaction between plants and fungi would have important ecosystem consequences. One example would be in the control of invasiveness in introduced plant species: surprisingly, naturalized plant species in Britain are disproportionately from mycorrhizal families, suggesting that these fungi may play a role in assisting invasion. 5What emerges from an attempt to relate biodiversity and ecosystem processes in soil is our extraordinary ignorance about the organisms involved. There are fundamental questions that are now answerable with new techniques and sufficient will, such as how biodiverse are natural soils? Do microbes have biogeography? Are there rare or even endangered microbes? [source] Ecology and management of exotic and endemic Asian longhorned beetle Anoplophora glabripennisAGRICULTURAL AND FOREST ENTOMOLOGY, Issue 4 2009Jiafu Hu Abstract 1The Asian longhorned beetle is native to China and Korea, and was found for the first time outside its native habitat in the U.S.A. in 1996, with subsequent detections being made in Canada and several European countries. 2We review the taxonomy, distribution, basic biology, behaviour, ecology and management of endemic and exotic Anoplophora glabripennis, including information that is available in the extensive Chinese literature. 3This species has caused massive mortality of Populus species in China and models have demonstrated that it could become established in many locations worldwide. 4Anoplophora glabripennis is polyphagous but prefers Acer, Salix and Populus, section Aigeiros. 5Although A. glabripennis adults do not disperse far when surrounded by host trees, they have the potential to fly more than 2000 m in a season. 6Volatile organic compounds from preferred host trees are attractive to A. glabripennis and this attraction is heightened by drought stress. Males and females orientate to a volatile released by female A. glabripennis and males attempt to copulate after contacting a sex pheromone on the female cuticle. 7At present, A. glabripennis is being (or has been) eradicated from areas where it has been introduced. After detection, extensive surveys are conducted and, if breeding populations are detected, at the very least, infested trees are removed and destroyed. Close attention is paid to imported solid wood packaging material to prevent new introductions. 8Standard practice to control A. glabripennis in China is to spray insecticides in tree canopies. In North America, largely as a preventative measure, systemic insecticides are injected into trees. Entomopathogenic fungi have been developed for the control of A. glabripennis, and entomopathogenic nematodes, coleopteran and hymenopteran parasitoids and predatory woodpeckers have been investigated as biocontrol agents. 9Ecological control of A. glabripennis in China involves planting mixtures of preferred and nonpreferred tree species, and this practice can successfully prevent outbreaks. [source] Integrating pharmacology topics in high school biology and chemistry classes improves performanceJOURNAL OF RESEARCH IN SCIENCE TEACHING, Issue 9 2003Rochelle D. Schwartz-Bloom Although numerous programs have been developed for Grade Kindergarten through 12 science education, evaluation has been difficult owing to the inherent problems conducting controlled experiments in the typical classroom. Using a rigorous experimental design, we developed and tested a novel program containing a series of pharmacology modules (e.g., drug abuse) to help high school students learn basic principles in biology and chemistry. High school biology and chemistry teachers were recruited for the study and they attended a 1-week workshop to learn how to integrate pharmacology into their teaching. Working with university pharmacology faculty, they also developed classroom activities. The following year, teachers field-tested the pharmacology modules in their classrooms. Students in classrooms using the pharmacology topics scored significantly higher on a multiple choice test of basic biology and chemistry concepts compared with controls. Very large effect sizes (up to 1.27 standard deviations) were obtained when teachers used as many as four modules. In addition, biology students increased performance on chemistry questions and chemistry students increased performance on biology questions. Substantial gains in achievement may be made when high school students are taught science using topics that are interesting and relevant to their own lives. © 2003 Wiley Periodicals, Inc. J Res Sci Teach 40: 922,938, 2003 [source] Up against the edge: invasive species as testbeds for basic questions about evolution in heterogeneous environmentsMOLECULAR ECOLOGY, Issue 21 2009ROBERT D. HOLT Yogi Berra is often credited, with having opined that ,prediction is very difficult, especially about the future'. There is no discipline for which this statement holds with more force than invasion biology, where it has been historically very challenging to predict the fate of introduced species (Williamson 2006). Some species after introduction quickly go extinct. Other relatively similar species may persist, but with little spread from their initial beachheads. Yet others can become aggressive invaders, with devastating consequences for native communities and ecosystems. This lack of predictability may of course sometimes reflect a simple lack of knowledge, both about key features of a species' basic biology, and about the environmental and community milieu in which invasion occurs (Williamson 2006). However, unpredictability may also arise from a fundamental fact about populations of living organisms , they almost always contain genetic variation, and so are not fixed entities responding to an environmental template, but instead labile in how they cope with the environment, over many spatial and temporal scales. Chance vicissitudes in the origination, maintenance and spatial organization of genetic variation could play a large role in generating the observed unpredictability in the fates of introduced species. The degree to which a particular introduced species becomes ,invasive', to the extent of coming to the attention of worried land managers, governmental officials and the public , may reflect in part its capacity for adaptive evolution across a wide range of environmental conditions. [source] Cytokines in temporomandibular joint arthritisORAL DISEASES, Issue 6 2000P Alstergren As the article in the current issue by Shinoda and colleagues shows, during the last two decades, there has been a dramatic increase in the understanding of basic biology behind chronic temporomandibular joint (TMJ) pain, inflammation and destruction. The involvement and contribution of cytokines to TMJ pain and inflammation must now be considered as established, evident and fundamental. Based on the present knowledge, it is now possible to design and investigate novel therapeutic strategies. These new and very encouraging approaches include manipulation of cytokine function, immune reactivity and the behaviour of inflammatory cells while maintaining the integrity of the affected tissue. [source] Biological control of terrestrial molluscs using Phasmarhabditis hermaphrodita,progress and prospectsPEST MANAGEMENT SCIENCE (FORMERLY: PESTICIDE SCIENCE), Issue 12 2007Robbie Rae Abstract Phasmarhabditis hermaphrodita Schneider (Nematoda: Rhabditidae) is a nematode that parasitises a wide range of slug and snail species. It has been formulated into a biological control agent (Nemaslug®) and was commercialised in 1994. It is now available in fourteen European countries. A review is given of all research on P. hermaphrodita, including basic biology, mass cultivation, formulation, host range, application strategies, field efficacy and effects on non-target organisms. The many critical gaps in present knowledge are highlighted, and future research is proposed that will lead to greater understanding of this unusual parasite and may enable its more widespread use in the management of mollusc pests. Copyright © 2007 Society of Chemical Industry [source] Tropical Montane Forest Restoration in Costa Rica: Overcoming Barriers to Dispersal and EstablishmentRESTORATION ECOLOGY, Issue 4 2000Karen D. Holl Abstract Tropical forests are being cleared at an alarming rate although our understanding of their ecology is limited. It is therefore essential to design restoration experiments that both further our basic knowledge of tropical ecology and inform management strategies to facilitate recovery of these ecosystems. Here we synthesize the results of research on tropical montane forest recovery in abandoned pasture in Costa Rica to address the following questions: (1) What factors limit tropical forest recovery in abandoned pasture? and (2) How can we use this information to design strategies to facilitate ecosystem recovery? Our results indicate that a number of factors impede tropical forest recovery in abandoned pasture land. The most important barriers are lack of dispersal of forest seeds and seedling competition with pasture grasses. High seed predation, low seed germination, lack of nutrients, high light intensity, and rabbit herbivory also affect recovery. Successful strategies to facilitate recovery in abandoned pastures must simultaneously overcome numerous obstacles. Our research shows that establishment of woody species, either native tree seedlings or early-successional shrubs, can be successful in facilitating recovery, by enhancing seed dispersal and shading out pasture grasses. On the contrary, bird perching structures alone are not an effective strategy, because they only serve to enhance seed dispersal but do not reduce grass cover. Remnant pasture trees can serve as foci of natural recovery and may enhance growth of planted seedlings. Our results highlight the importance of: (1) understanding the basic biology of an ecosystem to design effective restoration strategies; (2) comparing results across a range of sites to determine which restoration strategies are most generally useful; and (3) considering where best to allocate efforts in large-scale restoration projects. [source] Axin2 expression identifies progenitor cells in the murine prostateTHE PROSTATE, Issue 12 2008Christopher S. Ontiveros Abstract BACKGROUND We previously reported that prostatic stem/progenitor cells are concentrated in the proximal region of prostatic ducts and express stem cell antigen 1 (Sca-1). As Wnt signaling is important for the maintenance of stem cells, we determined whether Sca-1 expressing cells also express Axin2, as Axin2 expression is highly suggestive of active Wnt signaling. METHODS Axin2 promoter reporter mice were used for whole mount and fluorescence activated cell sorting (FACS) analysis to determine its expression in the prostate. Axin2 expressing cells were also examined for the co-expression of Sca-1. We also used a chemical activator of Wnt signaling, BIO, to determine the effects of Wnt signaling on the growth of primary prostate cells in vitro. RESULTS We show that Axin2 expression is present in all lobes and is regulated by androgens with the highest Axin2 expression in the lateral and dorsal prostate. Furthermore, a fraction of Axin2 expressing cells co-express Sca-1, suggesting that some progenitor cells have active Wnt signaling. Lastly, we demonstrate that activation of the Wnt pathway may result in increased growth, consistent with a role for Wnt signaling in maintenance and/or expansion of the progenitor cell population. CONCLUSION Axin2 expressing cells that co-express Sca-1 are present in all prostate lobes suggesting that progenitor cells reside within the Wnt active population. An understanding of the basic biology of signaling pathways mediating growth in the prostate may lead to rational therapies to treat benign prostatic hyperplasia and prostate cancer. Prostate 68:1263,1272, 2008. © 2008 Wiley-Liss, Inc. [source] The presence of rRNA sequences in polyadenylated RNA and its potential functionsBIOTECHNOLOGY JOURNAL, Issue 8 2008Qiongman Kong Abstract Accumulating evidence has shown that various lengths of ribosomal RNA (rRNA) sequences are widely present in polyadenylated RNA. This review article will discuss these polyadenylated rRNAcontaining transcripts (PART). PART are highly abundant and widely expressed in various tissues. It appears that there may be two types of PART. One type, type I, contains the rRNA segments (from ,10 nucleotides up to several hundred nucleotides) located within the transcripts. It has been demonstrated that short rRNA sequences within type I PART may function as cis-regulatory elements that regulate translational efficiency. The other type, type II, contains large portions or almost entire sequences of rRNA with a cap at the 5' end and poly(A) at 3' end. Recent work has shown that some type II PART have functional significance for some neurodegenerative disease processes and may play an important role in the pathogenesis of diseases. Further investigation in this area is critical to understanding the basic biology of PART and the potential role of PART in diseases. [source] Cardioprotection: spotlight on PKGBRITISH JOURNAL OF PHARMACOLOGY, Issue 6 2007M V Cohen Classical ischaemic preconditioning, delayed or second window preconditioning and postconditioning are forms of cardioprotection that are dependent on cell surface receptors, intracellular signalling molecules and kinases that ultimately block formation of the mitochondrial permeability transition. The latter is presumed to cause myocardial necrosis as well as apoptosis, so prevention of its formation upon resumption of perfusion after a prolonged coronary occlusion should be cardioprotective. In all of these forms of cardioprotection, formation of cGMP and activation of protein kinase G (PKG) are recognized to be key steps in the signal transduction pathway. Burley et al. highlight the roles of cGMP and PKG in their comprehensive review. They describe the basic biology of PKG and emphasize its compartmentalization, which may be responsible for the frustration induced by assays for PKG in whole cell lysates and for the spurious conclusions about the role of PKG in cardioprotection. This review will be useful to both the novice and the seasoned investigator. British Journal of Pharmacology (2007) 152, 833,834; doi:10.1038/sj.bjp.0707453; published online 17 September 2007 [source] TRANSLATIONAL RESEARCH GOES BOTH WAYS: LESSONS FROM CLINICAL STUDIESCLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY, Issue 4 2008John W Funder SUMMARY 1It is currently assumed that translational research goes from benchtop to bedside; that aldosterone elevates blood pressure via its effects on salt and water homeostasis; that mineralocorticoid receptors (MR) and glucocorticoid receptors (GR) share a common immediate ancestor; and that aldosterone plays a deleterious role in essential hypertension and heart failure. 2Meta-analysis of clinical trials in essential hypertension, in which eplerenone was dose-titrated to attain diastolic blood pressure < 90 mmHg, showed no relationship between blood pressure response and electrolyte effects, as judged by change in plasma (K). 3Reexamination of sequence data, and insights from the S810L MR mutant gene causing juvenile hypertension exacerbated by pregnancy, suggest that MR were the first to branch off the primordial ancestor for MR, GR, androgen receptors (AR) and progesterone receptors (PR). 4In clinical trials of MR blockade in heart failure and essential hypertension baseline aldosterone levels are in the low to normal range and sodium status unremarkable. Under such circumstances cortisol appears to be responsible for MR activation, thus exculpating aldosterone in these conditions. 5On the basis of these clinical studies, there is need to revisit the basic biology of aldosterone and MR as translational research very clearly goes both ways. [source] GENES, CALCIUM AND MODIFYING FACTORS IN HYPERTROPHIC CARDIOMYOPATHYCLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY, Issue 1-2 2006Tatiana Tsoutsman SUMMARY 1Familial hypertrophic cardiomyopathy (FHC) is a primary disorder of the myocardium characterized by remarkable diversity in clinical presentations, ranging from no symptoms to severe heart failure and sudden cardiac death. 2Over the past 15 years, at least 11 genes have been identified, defects of which cause FHC. Most of these genes encode proteins that comprise the basic contractile unit of the heart (i.e. the sarcomere). 3Genetic studies are now beginning to have a major impact on the diagnosis in FHC, as well as in guiding treatment and preventative strategies. Although much is known about which genes cause disease, relatively little is known about the molecular steps leading from the gene defect to the clinical phenotype and what factors modify the expression of the mutant genes. 4Concurrent studies in cell culture and animal models of FHC are now beginning to shed light on the signalling pathways involved in FHC and the role of both environmental and genetic modifying factors. Calcium dysregulation appears to be important in the pathogenesis of FHC. 5Understanding these basic molecular mechanisms will ultimately improve our knowledge of the basic biology of heart muscle function and will therefore provide new avenues for diagnosis and treatment not only for FHC, but also for a range of human cardiovascular diseases. [source] | |||||||||||||