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1.
The relationships of larval nutritional resources with adult body size, starvation resistance and reproductive decisions are not always clear. Burying beetle larvae with inadequate nutrition are hypothesized to develop into relatively large adults that are able to contest for breeding resources. The trade‐off is that the emerging adult has minimal energy reserves and is more susceptible to starvation, and must gain proportionately more weight after emerging. These hypotheses are investigated in Nicrophorus orbicollis Say. In addition, sex differences in size–mass ratios as well as starvation and recovery in reproductively mature females are examined. The larval mass to adult size ratio is similar in male and female N. Orbicollis and, contrary to prediction, small larvae do not result in adults that are relatively large in size for their mass. Emerging adults of lesser mass resist starvation less well, as expected. Emerging adults of smaller pronotal size gain more relative mass but less absolute mass than larger adults. In reproductively mature adult females, recovery from food deprivation is rapid, with most if not all the weight that is lost during a 9–10‐day starvation period being re‐gained within 1 day of engorging. The ability to gain weight rapidly and regulate body mass provides a nutritional framework for understanding the larva to adult transition and the reproductive and parenting decisions of burying beetles that otherwise would appear to be of too high risk.  相似文献   

2.
Emerging viral infections are becoming a serious problem in Europe in the recent years. This is particularly true for severe acute respiratory syndrome (SARS), West Nile virus (WNV) disease, Toscana virus (TOSV) disease, and potentially for avian influenza virus (H5N1). In contrast, emergence or re-emergence of severe viral infections, including tick borne encephalitis virus, and viral haemorrhagic fever caused by Hantavirus and dengue virus have been frequently reported in several European countries. Laboratory diagnosis of these viral infections based on viral isolation or detection by immune electron microscopy, immunoassay and polymerase chain reaction (PCR) has dramatically improved in the recent years, and SARS represents a good example of a diagnostic approach to emerging viral infections. Finally, old and new promising agents are in the pipeline of pharmaceutical companies to treat emerging viral infections. However only prevention based on large epidemiological studies, and research and development of new vaccines may be able to control and eventually eradicate these deadly viral infections.  相似文献   

3.
Emerging infectious diseases are a persistent threat to humans and food production but the mechanisms promoting the emergence of novel pathogens are not fully understood. The widely discussed explanations for pathogen emergence include range shifts, coincidental evolution of virulence, and host immunity variation. Here we propose a novel mechanism of virulence evolution that relies on environmental variability. Our model combines an environmental community experiencing random or periodic variability, to a classical SIR epidemiological model. We assume that environmentally growing, potentially infective variants arise at low frequency from a resident, non‐infective (benign microbial) strain through random variation on genetic material. We found that environmental perturbations commonly promote establishment of sporadic infections or persistent epidemics, by creating transient periods of low competition, which can in turn be exploited by an infective strain. Given the ubiquitous nature of potentially pathogenic environmental micro‐organisms and environmental variability, this mechanism provides a plausible explanation for emerging diseases.  相似文献   

4.
Emerging and reemerging infections pose a serious public health threat to most countries of tropical Africa. In the past decade, epidemics of diseases including cholera, dysentery, meningitis, yellow fever and Ebola virus have resulted in significant morbidity and mortality. Improved laboratory services and disease surveillance systems are essential to monitor disease trends and to initiate public health action. The present situation of emerging and reemerging infections in Africa is described in this review, and strategies for improved disease surveillance and monitoring are discussed.  相似文献   

5.
Emerging diseases are an ever‐growing affliction of both humans and wildlife. By exploring recent increases in amphibian malformations (e.g. extra or missing limbs), we illustrate the importance of food web theory and community ecology for understanding and controlling emerging infections. Evidence points to a native parasite, Ribeiroia ondatrae, as the primary culprit of these malformations, but reasons for the increase have remained conjectural. We suggest that the increase is a consequence of complex changes to aquatic food webs resulting from anthropogenic disturbance. Our results implicate cultural eutrophication as a driver of elevated parasitic infection: (1) eutrophication causes a predator‐mediated shift in snail species composition toward Planorbella spp., (2) Planorbella are the exclusive first intermediate hosts of R. ondatrae and (3) Ribeiroia infection is a strong predictor of amphibian malformation levels. Our study illustrates how the effects of anthropogenic disturbance on epidemic disease can be mediated through direct and indirect changes in food web structure.  相似文献   

6.
The development of durable and broad‐spectrum resistance is an economical and eco‐friendly approach to control crop diseases for sustainable agricultural production. Emerging knowledge of the molecular basis of pathogenesis and plant–pathogen interactions has contributed to the development of novel pathogen‐informed breeding strategies beyond the limits imposed by conventional breeding. Here, we review the current status of pathogen‐assisted resistance‐related gene cloning. We also describe how pathogen effector proteins can be used to identify resistance resources and to inform cultivar deployment. Finally, we summarize the main approaches for pathogen‐directed plant improvement, including transgenesis and genome editing. Thus, we describe the emerging role of pathogen‐related studies in the breeding of disease‐resistant varieties, and propose innovative pathogen‐informed strategies for future applications.  相似文献   

7.
《Trends in microbiology》2002,10(10):s3-s7
Emerging and re-emerging pathogens present a huge challenge to human and veterinary medicine. Emergence is most commonly associated with ecological change, and specific risk factors are related to the type of pathogen, route of transmission and host range. The biological determinants of host range remain poorly understood but most pathogens can infect multiple hosts, and three-quarters of emerging human pathogens are zoonotic. Surveillance is a key defence against emerging pathogens but will often need to be integrated across human, domestic animal and wildlife populations.  相似文献   

8.
Harvard Medical School convened a meeting of biomedical and clinical experts on 5 March 2015 on the topic of “Rethinking the Response to Emerging Microbes: Vaccines and Therapeutics in the Ebola Era,” with the goals of discussing the lessons from the recent Ebola outbreak and using those lessons as a case study to aid preparations for future emerging infections. The speakers and audience discussed the special challenges in combatting an infectious agent that causes sporadic outbreaks in resource-poor countries. The meeting led to a call for improved basic medical care for all and continued support of basic discovery research to provide the foundation for preparedness for future outbreaks in addition to the targeted emergency response to outbreaks and targeted research programs against Ebola virus and other specific emerging pathogens.  相似文献   

9.
This article examines the role of computation and quantitative methods in modern biomedical research to identify emerging scientific, technical, policy and organizational trends. It identifies common concerns and practices in the emerging community of computationally-oriented bio-scientists by reviewing a national symposium, Digital Biology: the Emerging Paradigm, held at the National Institutes of Health in Bethesda, Maryland, November 6th and 7th 2003. This meeting showed how biomedical computing promises scientific breakthroughs that will yield significant health benefits. Three key areas that define the emerging discipline of digital biology are: scientific data integration, multi-scale modeling and networked science. Each area faces unique technical challenges and information policy issues that must be addressed as the field matures. Here we summarize the emergent challenges and offer suggestions to academia, industry and government on how best to expand the role of computation in their scientific activities.  相似文献   

10.
Emerging opportunities are placing greater demands on device fabrication: next-generation microelectronics will need minimum features of less than 100 nm, high-throughput drug screening will require facile methods to incorporate sensitive biological components into microelectromechanical systems (MEMS), and implantable devices will need to be built from biocompatible materials. Increasingly, these emerging demands are being addressed by combining traditional microfabrication methods with 'biofabrication': namely, the use of biologically derived materials and biocatalysts. Recent fabrication techniques are using biological construction materials as process aids or structural components, and enzymes are being considered for their potential to fabricate devices with high selectivity under mild conditions. If incompatibilities between biology and microfabrication can be eliminated, then biofabrication will be poised to emerge as the standard for nanoscale construction.  相似文献   

11.
Okamoto Y  Nagai Y 《Uirusu》2007,57(2):207-215
The program of Founding Research Centers for Emerging and Reemerging Infectious Diseases was commenced in 2005 with an outline for Japanese universities and research institutions to establish bilateral collaboration research bases in countries where emerging and reemerging infections are breaking out or will likely break out. So far, six universities and two institutions are participating in the program and ten collaboration bases have been established in six countries (five in Asia and one in Africa). Each research base aims to contribute to the security and safety of the partner and own countries by facilitating better understanding of infectious diseases, technology innovation in diagnosis, therapy and prevention, and human resources development. The experiences of the Reseau International des Instituts Pasteur (RIIP), France, and the Wellcome Trust Southeast Asian Tropical Medicine Research Units (Oxford Network), United Kingdom, which appear to share similar missions, suggest that infectious diseases research that is based on overseas research bases can produce first-time results through the building of long-term mutual trust with the counterparts. By referring to these networks as models, Japan's program should be implemented over the long run but not be based on a short-time perspective. Thus, secure funding is a major issue.  相似文献   

12.
Emerging pathogens constitute a severe threat for human health and biodiversity. Determining the status (native or non‐native) of emerging pathogens, and tracing back their spatio‐temporal dynamics, is crucial to understand the eco‐evolutionary factors promoting their emergence, to control their spread and mitigate their impacts. However, tracing back the spatio‐temporal dynamics of emerging wildlife pathogens is challenging because (i) they are often neglected until they become sufficiently abundant and pose socio‐economical concerns and (ii) their geographical range is often little known. Here, we combined classical population genetics tools and approximate Bayesian computation (i.e. ABC) to retrace the dynamics of Tracheliastes polycolpus, a poorly documented pathogenic ectoparasite emerging in Western Europe that threatens several freshwater fish species. Our results strongly suggest that populations of T. polycolpus in France emerged from individuals originating from a unique genetic pool that were most likely introduced in the 1920s in central France. From this initial population, three waves of colonization occurred into peripheral watersheds within the next two decades. We further demonstrated that populations remained at low densities, and hence undetectable, during 10 years before a major demographic expansion occurred, and before its official detection in France. These findings corroborate and expand the few historical records available for this emerging pathogen. More generally, our study demonstrates how ABC can be used to determine the status, reconstruct the colonization history and infer key evolutionary parameters of emerging wildlife pathogens with low data availability, and for which samples from the putative native area are inaccessible.  相似文献   

13.
Osteopontin (OPN) is a pleiotropic cytokine produced both by immune and non-immune cells and active on different cellular targets. OPN production has been associated with several pathological conditions, including autoimmune diseases (e.g. lupus, multiple sclerosis and rheumatoid arthritis) and cancer. Emerging evidence suggests that the role of OPN has been underestimated, as it seems to be working at multiple levels of immune regulation, such as the shaping of T cell effector responses, the regulation of the tumor microenvironment, and the functional interaction with mesenchymal stromal cells. In this context, dendritic cells (DCs) play a crucial role being both an important source and a cellular target for OPN action. DC family is composed by several cell subsets endowed with specific immune functions. OPN exerts its biological functions through multiple receptors and is produced in different intracellular and secreted forms. OPN production by DC subsets is emerging as a crucial mechanism of regulation in normal and pathological conditions and starts to be exploited as a therapeutic target. This review will focus on the role of DC-derived OPN in shaping immune response and on the complex role of this cytokines in the regulation in immune response.  相似文献   

14.
Emerging zoonoses have been defined as zoonoses that are newly recognised or newly evolved, or that have occurred previously but show an increase in incidence or expansion in geographical, host or vector range. Among parasitic zoonoses, protozoa are particularly likely to emerge. Control and prevention of emerging parasitic zoonoses are complex tasks that require an integrative and multidisciplinary approach. Reduction of parasite burden is certainly a major objective but cannot be set alone. Therefore, environmental and ecological modifications need to be implemented to reduce not only the parasitic load, but also the risk of parasite transmission. Finally, education and behavioral changes are critical for the success of both control and prevention of these diseases. However, without appropriate financial resources specifically allocated at the local and national levels as well as through international cooperation, control and prevention of these emerging parasitic diseases will not be possible.  相似文献   

15.
Life cycle assessment (LCA) has been applied for assessing emerging technologies, where large‐scale production data are generally lacking. This study introduces a standardized scheme for technology and manufacturing readiness levels to contextualize a technology's development stage. We applied the scheme to a carbon nanotube (CNT) LCA and found that, regardless of synthesis technique, CNT manufacturing will become less energy intensive with increased levels of readiness. We examined the influence of production volume on LCA results using primary data from a commercial CNT manufacturer with approximately 100 grams per day production volume and engineering design of a scaled‐up process with 1 tonne per day production capacity. The results show that scaling up could reduce 84% to 94% of its cradle‐to‐gate impacts, mainly as a result of the recycling of feedstock that becomes economically viable only beyond certain minimum production volume. This study shows that LCAs on emerging technologies based on immature data should be interpreted in conjunction with their technology and manufacturing readiness levels and reinforces the need of standardizing and communicating information on these readiness levels and scale of production in life cycle inventory practices.  相似文献   

16.
Coronavirus disease 2019 (COVID‐19), the worst pandemic in more than a century, has claimed >125,000 lives worldwide to date. Emerging predictors for poor outcomes include advanced age, male sex, preexisting cardiovascular disease, and risk factors including hypertension, diabetes, and, more recently, obesity. This article posits new obesity‐driven predictors of poor COVID‐19 outcomes, over and above the more obvious extant risks associated with obesity, including cardiometabolic disease and hypoventilation syndrome in intensive care patients. This article also outlines a theoretical mechanistic framework whereby adipose tissue in individuals with obesity may act as a reservoir for more extensive viral spread, with increased shedding, immune activation, and cytokine amplification. This paper proposes studies to test this reservoir concept with a focus on specific cytokine pathways that might be amplified in individuals with obesity and COVID‐19. Finally, this paper underscores emerging therapeutic strategies that might benefit subsets of patients in which cytokine amplification is excessive and potentially fatal.  相似文献   

17.
Interactions between fungi and bacteria and their relevance to human health and disease have recently attracted increased attention in biomedical fields. Emerging evidence shows that bacteria and fungi can have synergistic or antagonistic interactions, each with important implications for human colonization and disease. It is now appreciated that some of these interactions may be strategic and helps promote the survival of one or both microorganisms within the host. This review will shed light on clinically relevant interactions between fungi and Gram‐negative bacteria. Mechanism of interaction, host immune responses, and preventive measures will also be reviewed.  相似文献   

18.
Prior to the advent of antibiotics, live organisms were used directly in attempts to control microbial infections and cure cancers. Examples of such biological control included bacteriotherapy, bacteriophage therapy, malaria therapy, probiotics and the use of living maggots. In all cases, the organisms themselves, rather than products of their metabolism, were used as the potentially curative agents. The history of the use of biocontrol agents in the treatment of human infections and cancer is discussed here in relation to more recent examples of the use of this approach. Modern studies suggest that the use of biological control in the treatment of human infections may be worth re‐evaluating in the light of the increasing world‐wide occurrence of antibiotic‐resistant bacteria and the opportunities provided by recent developments in gene technology.  相似文献   

19.
Whary MT  Fox JG 《Lab animal》2006,35(7):25-7, 30-6
Researchers first isolated and characterized Helicobacter hepaticus in 1994 as a cause of hepatitis that progressed to hepatocellular carcinoma in A/JCr mice. During the past decade, isolation and characterization of additional novel helicobacters from rodents has continued. In addition to causing overt disease, rodent helicobacter infections are important because intercurrent disease in select models will confound research data. Emerging evidence suggests that inflammatory responses to enterohepatic helicobacter infections may alter host responses to other experimental stimuli in unanticipated ways. Additionally, scientists have experimentally infected a variety of inbred mouse strains and genetically engineered mice with a variety of Helicobacter spp. isolated from rodents, birds, and higher mammals (including humans) to develop animal models of gastrointestinal diseases as well as idiopathic human disease syndromes. This review highlights current information about helicobacter infections in laboratory rodents and provides recommendations for the detection and eradication of these infections. The authors discuss the impact of subclinical and clinical disease and offer recommendations for managing helicobacter-free rodent colonies.  相似文献   

20.
Emerging and re-emerging infectious diseases have become a major global environmental problem with important public health, economic, and political consequences. The etiologic agents of most emerging infectious diseases are zoonotic, and anthropogenic environmental changes that affect wildlife communities are increasingly implicated in disease emergence and spread. Although increased disease incidence has been correlated with biodiversity loss for several zoonoses, experimental tests in these systems are lacking. We manipulated small-mammal biodiversity by removing non-reservoir species in replicated field plots in Panama, where zoonotic hantaviruses are endemic. Both infection prevalence of hantaviruses in wild reservoir (rodent) populations and reservoir population density increased where small-mammal species diversity was reduced. Regardless of other variables that affect the prevalence of directly transmitted infections in natural communities, high biodiversity is important in reducing transmission of zoonotic pathogens among wildlife hosts. Our results have wide applications in both conservation biology and infectious disease management.  相似文献   

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