The MUC family: an obituary

Mucins are glycoproteins that are common on the surfaces of many epithelial cells; they are deemed to mediate many interactions between these cells and their milieu. Several of these mucins form the mucus layer that is found in many hollow organs. The biophysical properties of mucins are related to their extensive O-linked glycosylation rather than directly to their polypeptide sequences. Despite the frequent absence of sequence homology, many human genes encoding mucins have been named MUC followed by a number, unjustly suggesting the existence of one large gene family. In this article, it is suggested that the mucin genes be renamed according to their sequence homologies.     

Central role of quorum sensing in regulating the production of pathogenicity factors in Pseudomonas aeruginosa.

Pseudomonas aeruginosa is an important opportunistic human pathogen, causing various infections that are often very persistent. P. aeruginosa infections are the major cause of death in cystic fibrosis patients. Infections are difficult to treat since P. aeruginosa is resistant to most antibiotics and its antibiotic susceptibility is decreased when it is present in biofilms. P. aeruginosa produces many exoproducts (including toxins and hydrolytic enzymes) that are involved in virulence. Recent research has elucidated many mechanisms and pathways that regulate the production of these virulence factors. The regulation is extremely complex and many components are influenced by environmental conditions. Quorum sensing is a key regulatory system, which itself is affected by many other regulators. Targeting the regulation of pathogenicity factors provides a novel strategy for combating P. aeruginosa infections. Degradation of acyl homoserine lactones, the signaling molecules of the quorum-sensing system, is a promising therapeutic treatment option.     

Multilocus selection in subdivided populations II. Maintenance of polymorphism under weak or strong migration

The potential of maintaining multilocus polymorphism by migration-selection balance is studied. A large population of diploid individuals is distributed over finitely many demes connected by migration. Generations are discrete and nonoverlapping, selection may vary across demes, and loci are multiallelic. It is shown that if migration and recombination are strong relative to selection, then with weak or no epistasis and intermediate dominance at every locus and in every deme, arbitrarily many alleles can be maintained at arbitrarily many loci at a stable equilibrium. If migration is weak relative to selection and recombination, then with weak or no epistasis and intermediate dominance at every locus and in every deme, as many alleles as there are demes can be maintained at arbitrarily many loci at equilibrium. In both cases open sets of such parameter combinations are constructed, thus the results are robust with respect to small, but arbitrary, perturbations in the parameters. For weak migration, the number of demes is, in fact, a generic upper bound to the number of alleles that can be maintained at any locus. Thus, several scenarios are identified under which multilocus polymorphism can be maintained by migration-selection balance when this is impossible in a panmictic population.      

Estimation of the most probable number with a programable pocket calculator.

The most-probable-number method has many potential applications, particularly if many tubes per dilution and many dilution levels are used. Increasing the number of cultures is possible with modern automatic and semiautomatic equipment. However, available tables are not sufficiently detailed to handle data from a large number of culture tubes used in an assay. This paper provides a computer program capable of handling the necessary arithmetic and written for a hand-held, advanced programable calculator.     

Endocytosis of G Protein-Coupled Receptors and Their Ligands: Is There a Role in Metal Trafficking?

The prevalence of metal dysregulation in many neurodegenerative and neurocognitive disorders has compelled many studying such diseases to investigate the mechanisms underlying metal regulation in the central nervous system. Metal homoeostasis is often complex, with sophisticated, multilayered pathways in operation. G protein-coupled receptors are omnipresent on cell membranes and have intriguing mechanisms of endocytosis and trafficking that may be useful in metal homoeostasis. Indeed, many receptors and/or their cognate ligands are able to bind metals, and in many cases metals are considered to have neuromodulatory roles as a result of receptor binding. In this mini-review, we outline the structural and functional aspects of G protein-coupled receptors with a focus on the mechanisms leading to endocytosis and cellular trafficking. We further highlight how this may help in the trafficking of metal ions, notably copper.     

The good viruses: viral mutualistic symbioses

Although viruses are most often studied as pathogens, many are beneficial to their hosts, providing essential functions in some cases and conditionally beneficial functions in others. Beneficial viruses have been discovered in many different hosts, including bacteria, insects, plants, fungi and animals. How these beneficial interactions evolve is still a mystery in many cases but, as discussed in this Review, the mechanisms of these interactions are beginning to be understood in more detail.     

The Crystals in the Ovaries of certain Compositae

The inner tissues of the ovary wall in many Compositae containcrystals of calcium oxalate. These are of many different forms,some of which are of very restricted taxonomic distribution.These crystals are organized inclusions of the cell, many ofthem having a complex internal structure which is not explicablein terms of a homogeneous crystal lattice.     

The diversity, distribution and ecology of diatoms from Antarctic inland waters

Diatoms are abundant and diverse in many Antarctic freshwaters, with a general trend of decreasing diversity moving southwards. They form an important component of many benthic algal communities in streams and standing waters but are generally less common in the phytoplankton. Diatoms are excellent ecological indicator species and, because their remains are preserved in many sedimentary environments, there appears to be a great potential for palaeoenvironmental reconstruction and the examination of past diversity. A lack of taxonomic precision and consistency, coupled with the insufficient collection from some geographical areas, makes the estimation of the number of Antarctic diatom species problematic.     

An overview of the serpin superfamily

Serpins are a broadly distributed family of protease inhibitors that use a conformational change to inhibit target enzymes. They are central in controlling many important proteolytic cascades, including the mammalian coagulation pathways. Serpins are conformationally labile and many of the disease-linked mutations of serpins result in misfolding or in pathogenic, inactive polymers.     

On the kinetic depth effect

The problem of the kinetic depth effect is revisited. We study how many points in how many views are necessary and sufficient to recover structure. The constraints in the cases where the velocities of the image points are known, and the positions of the image points are known with the correspondence between them established, are different and they have to be studied separately. In the case of two projections of any number of points there are infinitely many solutions, but if we regularize the problem we get a unique solution under some assumptions. Finally, an algorithm is discussed for learning this particular kind of regularization.     

Polyglutamine-mediated neurodegeneration: Use of chaperones as prevention strategy

Polyglutamine diseases are a class of inherited neurodegenerative disorders caused by the expansion of a polyglutamine tract within the respective proteins. Clinical studies have revealed that the forming of neuronal intranuclear inclusions by the disease protein is a common pathological feature of polyglutamine diseases. Although there has been considerable progress in understanding polyglutamine diseases, many questions regarding their mechanism are still unanswered. The finding that molecular chaperones are associated with ubiquitinated intranuclear inclusions clearly indicates a crucial role of molecular chaperones in the generation of these fatal diseases. Molecular and chemical chaperones have been found to be a good agent for suppressing many polyglutamine diseases in several animal models. In this review, I discuss the roles of the ubiquitin-proteasome pathway and molecular chaperones in the development of polyglutamine diseases and probable approach for the prevention of many of these fatal disorders using molecular chaperones as a therapeutic agent. Newly found chemical chaperones have been demonstrated to be potentially useful and could be used as a therapeutic strategy in preventing many versions of polyglutamine diseases.     

Weather and fireblight in England

Agriculture in tropical countries produces many of the world's most valuable crops, but productivity is limited by a multiplicity of different diseases, many of which have been inadequately studied. Certain characteristics of tropical climates have a fundamental influence on the incidence and severity of many of these diseases. The main seasonal variations which control crop growth and disease epidemiology depend on differences in moisture availability rather than daylength and temperature differences. Marked dry seasons hinder the survival of many pathogens outside hosts unless they can produce drought-resistant spores. In many tropical areas continuous cropping throughout the year is possible, enabling disease epidemics to continue without interruption over long periods. Much agriculture in the tropics is at fairly high altitudes enabling temperate crops to be grown, but low temperatures may present special disease hazards. Violent storms are a feature of many tropical climates and have been implicated in the spread of many bacterial diseases. Drought is a factor which influences the severity of many root diseases. The various effects which moisture, as rain or dew, temperature and cropping cycle can have are illustrated by discussion of sigatoka disease of bananas (Mycosphaerella musicola Leach), South American leaf blight of rubber (Microcyclus ulei (R. Henn.) Arx) and coffee berry disease (Colletotrichum coffeanum Noack).     

How common are invasion-induced ecosystem impacts?

It would be an exaggeration to argue that most invasions produce ecosystem impacts, and the term should be reserved for cases in which many species in an ecosystem are affected. However, certain facts suggest that true ecosystem impacts are more common than is normally assumed. First, the term “ecosystem impact” has often been reserved for cases in which the nutrient regime or nutrient cycling is affected, whereas physical structural and other changes in ecosystems ought to be included. Second, as with all ecology, very few systems and species have been studied relative to all those that exist, so it is likely that many ecosystem impacts remain to be detected. Third, there are many types of impacts, many are idiosyncratic, many are subtle, and many are indirect, so it is likely that many impacts have simply not been recognized even in studied systems. Finally, the frequency of the lag phenomenon in invasions implies that at least some existing non-native species that are currently having little or no impact will eventually have much greater ones. These facts suggest that, even if it would be an overstatement to say that most invasions cause ecosystem impacts, it would not be more of an overstatement than the common assertion that very few introduced species have any significant impact.     

Evolution Education: Seeing the Forest for the Trees and Focusing Our Efforts on the Teaching of Evolution

Evolution is the underlying framework upon which all biology is based; however, when it comes to learning evolutionary concepts, many students encounter obstacles. There are many reasons as to why these obstacles occur. These reasons deal with evolution being treated as a discrete topic among many within a biology curriculum, misunderstanding the nature of science, and personal difficulties with understanding due to evolution’s seemingly abstract nature. In this article, we propose a different way of thinking about and teaching evolution in grades K-12, and it surrounds four core areas essential to the understanding of evolution: variation, selection, inheritance, and deep time. Possibilities for how these areas can affect learning are described and implications for assessment are also discussed.     

Light of my life--messages in the dark

Luminescent lures, counter-shading in the dark blue sea, flashes of light intensive enough to temporarily blind a predator, love fireworks in the night to impress a mate, and toadstools that glow to attract parasitic wasps--these are just some of the many examples of bioluminescence at work in Nature. But how is the biological light produced? What are its evolutionary roots? Why are there so many different uses for the light?     

Applications from bacterial adhesion and biofilm studies in relation to urogenital tissues and biomaterials: A review

Summary The urogenital tract, particularly of the adult female, is the habitat for many species of microorganisms. These populations are in a state of flux, are susceptible to disruption by antibiotics and spermicides, and are exposed to many different biomaterial substrata. Infections of the genital area and bladder are common, and are invariably initiated by microbial adhesion to surfaces. This review examines the actual and potential applications to industry and to patients emerging from the study of bacterial adhesion to surfaces.     

What do tadpoles really eat? Assessing the trophic status of an understudied and imperiled group of consumers in freshwater habitats

1. Understanding the trophic status of consumers in freshwater habitats is central to understanding their ecological roles and significance. Tadpoles are a diverse and abundant component of many freshwater habitats, yet we know relatively little about their feeding ecology and true trophic status compared with many other consumer groups. While many tadpole species are labelled herbivores or detritivores, there is surprisingly little evidence to support these trophic assignments. 2. Here we discuss shortcomings in our knowledge of the feeding ecology and trophic status of tadpoles and provide suggestions and examples of how we can more accurately quantify their trophic status and ecological significance. 3. Given the catastrophic amphibian declines that are ongoing in many regions of the planet, there is a sense of urgency regarding this information. Understanding the varied ecological roles of tadpoles will allow for more effective conservation of remaining populations, benefit captive breeding programmes, and allow for more accurate predictions of the ecological consequences of their losses.     

Insects as a piece of the puzzle to mitigate global problems: an opportunity for ecologists

Although scientists have studied and touted the importance of insects to many ecosystem services for decades, insects and insect science are often poorly perceived by the public and by policy makers. Because insects do have important influences on many ecosystem services, they have even greater potential to be used to solve some anthropogenically-caused current global problems. We give several examples where insects are currently being used, or are being considered for future use, as a part of the solution to a global problem, including their potential roles as a part of the solution to sustainable fuel and food systems, deforestation and other environmental degradation, and global inequities. Ecologists have an important role to play in assessing how many of the proposed uses of insects will alter ecological processes and ecosystem services, or how their use may be effectively implemented.     

选择性剪接在低氧应答中的调控作用

细胞为适应低氧环境,其相关基因的表达方式发生了改变,其中选择性剪接在低氧应答调控过程中起到了重要的作用。低氧诱导因子介导的低氧应答信号通路在机体适应低氧环境过程中起到了十分重要的作用,低氧诱导因子剪接体通过此通路调控红细胞生成、血管生成、糖酵解等过程。而抑制性PAS蛋白质、脯氨酸羟化酶、促血管生长因子、芳香羟受体核转运蛋白剪接体则通过其它通路进行调控。选择性剪接不仅在低氧应答中起重要作用,而且与阿尔茨海默病、动脉粥样硬化、癌症等常见人类疾病相关。