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1.
Plants are under constant attack by a vast array of pathogens. To impede their attackers they use both broad-spectrum and pathogen-specific defence mechanisms. The arms race between plants and fungal pathogens is fascinatingly varied, and what might be elicited as a plant defence mechanism against a pathogen could promote or enhance the virulence of other pathogens. Fungi use countermeasures to detoxify plant antimicrobial compounds and to evade host resistance mechanisms. Certain fungal species also manipulate the host hormone balance to create an environment that is beneficial to their survival. Several lines of evidence indicate a co-evolutionary arms race in which both plants and fungi can respond to changes that occur in their opponents.  相似文献   

2.
It is widely accepted that the notions of ‘race’ and ‘ethnicity’ are socially constructed: they refer in other words to culturally shaped conceptions of identity that may or may not have any specific relationship to underlying genetic or visible phenotypical characteristics of the individuals or groups in question. While this has allowed manifestations of racism to be identified for what they are – malignant myths – an over-sociological conception of race and ethnicity can easily overlook other significant, and fluid, forms of identity formation and transformation. This editorial suggests some of these forms and posits ways in which they might inform thinking about race and ethnicity in fresh ways, especially drawing on recent advances in performance theory.  相似文献   

3.
4.
Abstract

The use of plastic produced from non-renewable resources constitutes a major environmental problem of the modern society. Polylactide polymers (PLA) have recently gained enormous attention as one possible substitution of petroleum derived polymers. A prerequisite for high quality PLA production is the provision of optically pure lactic acid, which cannot be obtained by chemical synthesis in an economical way. Microbial fermentation is therefore the commercial option to obtain lactic acid as monomer for PLA production. However, one major economic hurdle for commercial lactic acid production as basis for PLA is the costly separation procedure, which is needed to recover and purify the product from the fermentation broth. Yeasts, such as Saccharomyces cerevisiae (bakers yeast) offer themselves as production organisms because they can tolerate low pH and grow on mineral media what eases the purification of the acid. However, naturally yeasts do not produce lactic acid. By metabolic engineering, ethanol was exchanged with lactic acid as end product of fermentation. A vast amount of effort has been invested into the development of yeasts for lactic acid production since the first paper on this topic by Dequin and process insight. If pH stress is used as basis for DNA microarray analyses, in order to improve the host, what exactly is addressed? Growth? Or productivity? They might be connected, but can be negatively correlated. A better growing strain might not be a better producer. So if the question was growth, the answer might not be what was initially intended (productivity).

A major task for the future is to learn to ask the right questions – a lot of studies intended to lead to better productivity, did lead to interesting results, but NOT to better production strains.

Taking together what we learned from lactic acid production with yeasts, we see a bright future for bulk and fine chemical production with these versatile hosts.  相似文献   

5.
Unlike bigger and more advanced animals, Caenorhabditis elegans does not generate NO, yet it was recently found that NO produced by chemical or biological sources exerts profound effects in that animal, leading to increased life span and thermotolerance. The biological source was Bacillus subtilis, a natural food for C. elegans. Yet once in the cell, NO might react with superoxide, leading to the production of the potentially toxic peroxynitrite. In this paper, a number of paradoxes that are involved in that situation are discussed. It is also argued that their solution might lead to a sizeable advancement of our knowledge of what constitutes oxidative stress and what role oxidative stress plays in the development of pathological processes and aging.  相似文献   

6.
ABSTRACT

Contemporary discussion about race has a tendency to set off out without first checking the rear view mirror. In Theories of Race and Ethnicity: Contemporary Debates and Perspectives, in contrast, Murji and Solomos identify what has and has not been covered, and so appeal at the outset for a ‘more sustained’ account of changing research agendas of race and ethnic relations. Taken as a whole, the collection allows the editors to contemplate ‘what factors explain the mobilizing power of ideas about race and ethnicity in the contemporary environment?' and whether indeed ‘it is the “real” rather than race that should be placed in quotation marks’.  相似文献   

7.
Prior work has considered how our genetic knowledge might allow for personalized medicine. This commentary explores the reverse question of what personalized genetic medicine might do to our research process, not only in genetics, but in epidemiology more generally.  相似文献   

8.
This address considers ethnographically a range of sites and practices central to sustaining the intellectual, pedagogical, professional, and public life of anthropology and related disciplines: research funding, human subjects review, scholarly publishing, program and personnel assessment, and intellectual property among them. The talk points to current practices of knowledge production and circulation in the United States and to the increasingly complex intersections among scholarly knowledge, managerialist language and practice, and private capital, intellectual and otherwise. It is meant to encourage serious ethnographic examination of the contexts within which anthropologists work, consideration of the potential consequences of these contemporary changes, and creative thought about the kinds of collegial and collective action that might be pursued to help sustain what we find to be of real value in the discipline and in our professional practice.  相似文献   

9.
This article examines biosocial criminology’s partial social constructionism of race, that is a logic of difference that attempts to accommodate both a social and biological interpretation of race. We focus on the way biosocial criminologists operationalize race to outline the sociological consequences of what we see as a renewed commitment to the bio-criminalization of race. Biosocial criminologists do not reject that race is socially constructed, but in practice they disregard the main consequences and raison d’être of this postulate. Though biosocial criminologists praise the incorporation of cutting-edge science into criminology, the research programme’s actual findings concerning race do not necessarily align with views from genetic and neuroscientific research. Instead, we argue that biosocial criminology solicits social constructionism as a shield to re-insert antiquated biologic notions of race through a guise of bio-sociality.  相似文献   

10.
Climate change is real. The wrangling debates are over, and we now need to move onto a predictive ecology that will allow managers of landscapes and policy makers to adapt to the likely changes in biodiversity over the coming decades. There is ample evidence that ecological responses are already occurring at the individual species (population) level. The challenge is how to synthesize the growing list of such observations with a coherent body of theory that will enable us to predict where and when changes will occur, what the consequences might be for the conservation and sustainable use of biodiversity and what we might do practically in order to maintain those systems in as good condition as possible. It is thus necessary to investigate the effects of climate change at the ecosystem level and to consider novel emergent ecosystems composed of new species assemblages arising from differential rates of range shifts of species. Here, we present current knowledge on the effects of climate change on biotic interactions and ecosystem services supply, and summarize the papers included in this volume. We discuss how resilient ecosystems are in the face of the multiple components that characterize climate change, and suggest which current ecological theories may be used as a starting point to predict ecosystem-level effects of climate change.  相似文献   

11.
12.
In this paper, we explore the tensions around a recent controversial development in medical tourism: xenotourism in Mexico. We take this bioendeavor – now ceased – to be emblematic of the global character of contemporary biomedicine, providing insights into the production and operation of scientific knowledge. We explore this through what we call the “textures of globalization”: the anxiety regarding the extent to which Mexico was understood as an (in)appropriate venue for the generation of novel knowledge on xenotransplantation, and as a location for xenotourism. These tensions, which oscillated between calls for individual freedom (choice) and global regulation (standardization), ultimately led to the closure of xenotourism in Mexico.  相似文献   

13.
Organisms embedded within food webs must balance arms races with their predators and prey. For venom users, venom may mediate each arms race, but the dynamical evolutionary changes in venom production in response to the two arms races are still poorly understood. Here, we use a simple model to evaluate the evolutionary response of a venomous consumer to the presence of an apex generalist predator and evolution of the consumer’s prey. We find that introduction of the apex predator can weaken the arms race between the two lower trophic levels. In addition, when consumer prey capture and predator defense venoms functionally overlap, a reduced evolutionary response in the prey population can drive investment in venom used for prey capture going beyond what is optimal for subduing prey. These dynamics suggest that interactions with multiple trophic levels can substantially alter the venom complexity in predatory venomous animals and may explain the paradox of the overkill hypothesis.  相似文献   

14.
How successful are multinational corporations in extending their firm-based environmental standards to their subsidiaries and those subsidiaries' local suppliers in their global production networks in developing countries? We address this question through an in-depth case study of how Motorola, a prominent multinational electronics firm with an extensive global production network, is using a set of firm-based standards to meet several new stringent European Union environmental directives. The case study demonstrates that these firm-based standards appear to be enabling a major subsidiary and its suppliers in one developing economy to reduce the environmental intensities of their production activities. This finding suggests that the firm-based environmental standards of multinationals with extensive global production networks might contribute to a leveling up of environmental standards in subsidiaries and their local suppliers, rather than a "race to the bottom", thus reinforcing the technique or intensity effects associated with open trade, investment, and technology policies.  相似文献   

15.
《Anthropological Forum》2012,22(3):251-270
In 2010, Porer Nombo and I launched a book about indigenous Papua New Guinean plant knowledge to a large audience at a university near to his village on the north coast of that country. Members of the audience commented that the book made a record of important practices. But they asked if those practices were dependent on secret magic to be effective? What gave us the right to include such secrets? Or, if there was in fact something fundamental missing from the book (magical formulae to activate the processes described), then what was the use of publishing the book? Thinking through their questions suggested the need to analyse what ‘knowledge’ is in different places, and why plants might be effective in some, but not others. In this paper I attempt an explanation that does not rely on a ‘social’ explanation of magic but instead suggest that what we call ‘magic’ are mechanisms whereby a gardener (or healer, or hunter) positions an action, or a thing in relation to other things. I liken the way myth works in these systems to the way intellectual property law provides a comparable ‘mythic’ structure that locates effect in the places that have developed ‘knowledge economies’ and I conclude by asking; if places embody their history and politics, and generate different understandings of effect, then what are the implications of calling Porer's practices with regard to plants, ‘knowledge’?  相似文献   

16.
Race talk within discourse analytic traditions have largely focused on the discursive construction of racism in majority groups. This article extends this work by examining how Black adults discursively engaged in race talk. Across focus groups, two conversations emerged: explanations of racialized experiences and how racialized experiences should be dealt with. In explanations of racialized experiences, participants highlighted their own negative behaviours or constructed experiences as imprecise or an artefact of ignorance. These discourses functioned to circumvent inequitable relations premised on White normativity. In explanations of how racialized experiences should be dealt with, participants constructed themselves as having responsibilities, downplayed their racialized experiences or framed them as inevitable. Each of these discourses functioned to construct racialization as something that could be corrected through good behaviour or they placed ideological limits for what is possible for Blacks in society. Implications for the existing literature on race talk are discussed.  相似文献   

17.
Speech production involves the movement of the mouth and other regions of the face resulting in visual motion cues. These visual cues enhance intelligibility and detection of auditory speech. As such, face-to-face speech is fundamentally a multisensory phenomenon. If speech is fundamentally multisensory, it should be reflected in the evolution of vocal communication: similar behavioral effects should be observed in other primates. Old World monkeys share with humans vocal production biomechanics and communicate face-to-face with vocalizations. It is unknown, however, if they, too, combine faces and voices to enhance their perception of vocalizations. We show that they do: monkeys combine faces and voices in noisy environments to enhance their detection of vocalizations. Their behavior parallels that of humans performing an identical task. We explored what common computational mechanism(s) could explain the pattern of results we observed across species. Standard explanations or models such as the principle of inverse effectiveness and a "race" model failed to account for their behavior patterns. Conversely, a "superposition model", positing the linear summation of activity patterns in response to visual and auditory components of vocalizations, served as a straightforward but powerful explanatory mechanism for the observed behaviors in both species. As such, it represents a putative homologous mechanism for integrating faces and voices across primates.  相似文献   

18.
Herbivory is a major energy transfer within ecosystems; an open question is under what circumstances it can stimulate aboveground seasonal primary production. Despite multiple field demonstrations, past theory considered herbivory as a continuous process and found stimulation of seasonal production to be unlikely. Here, we report a new theoretical model that explores the consequences of discrete herbivory events, or episodes, separated in time. We discovered that negative density (biomass) dependence of plant growth, such as might be expected from resource limitation of plant growth, favors stimulation of seasonal production by infrequent herbivory events under a wide range of herbivory intensities and maximum plant relative growth rates. Results converge to those of previous models under repeated, short‐interval herbivory, which generally reduces seasonal production. Model parameters were estimated with new and previous data from the Serengeti ecosystem. Patterns of observed frequent and large magnitude stimulated production in these data agreed generally with those predicted by the episodic herbivory model. The model thus may provide a new framework for evaluating the sustainability and impact of herbivory.  相似文献   

19.
At the implantation site, the uterine mucosa (decidua) is infiltrated by large numbers of natural killer (NK) cells. These NK cells are in close contact with the invading fetal trophoblast and we have proposed that they might be the effector cells that control the implantation of the allogeneic placenta. Recent characterization of NK cell receptors and their HLA class I ligands has suggested potential mechanisms by which NK cells might interact with trophoblast. However, what happens as a result of this interaction is not clear. The traditional method for investigating NK cell function in vitro is the protection from lysis of target cells by expression of HLA class I antigens. This might not be an accurate reflection of what happens in vivo. Another function of NK cells is the production of cytokines on contact with target cells. This could be an important outcome of the interaction between decidual NK cells and trophoblast. Decidual NK cells are known to produce a variety of cytokines; trophoblast cells express receptors for many of these cytokines, indicating that they can potentially respond. In this way, decidual NK cells have a significant influence on trophoblast behaviour during implantation.  相似文献   

20.
This paper critiques the theorisation of culture as difference that dominates Australian cultural studies and cultural anthropology. It argues that a perspective on culture that gets beyond current preoccupations with difference has more to be said for it than practitioners in either discipline have hitherto recognised. Ethnography has long been recognised as crucial to the study of culture—which suggests that we might best appreciate what it is that is being ignored and neglected (not to say demeaned) in contemporary studies of culture if we turn our attention to the way we study it. This paper reconsiders what we mean by the assertion that ethnography constitutes an experiential mode of knowledge which constitutes the most sustained and rigorous application of the principle of verstehen available. In contesting the stress on difference that now dominates the study of culture, a case is made for cultures conceived of as ensembles of mystery and meaning. Whether born into a culture or researching it, as observers and participants we struggle to make sense of what the world is about. As ethnographers, we seek to do this empathically; this paper argues that to do it effectively we must fashion a sensibility adequate to it. An appreciation of the significance of sensibility, it is suggested, provides a much needed alternative to the reduction of culture to difference.  相似文献   

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