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SYNOPSIS. The controversy over whether functional data can contributeto phylogenetic inference has grown in recent years. Steps canbe taken toward its resolution if the relevance of functionaldata is judged for each component of phylogenetic analysis.These components are (1)recognizing of basic taxa (species orsupraspecific taxa), (2) formulating hypotheses of homologyfollowed by character analysis, (3) evaluating character phylogeny,(4) formulating phylogenetic hypotheses, and (5) evaluatingalternative phylogenetic hypotheses. It can be shown that functionaldata do not play a necessary or unique role in any of thesecomponents of phylogenetic analysis. Arguments to the contraryhave failed to provide a rigorous, repeatable methodto incorporatefunctional data; proponents of a functional approach to phylogeneticreconstruction rely too often on subjective, authoritarian argumentation. Students of functional evolutionary morphology frequently havefailed to understand the kinds of information necessary to studyor apply the causal process of adaptation via natural selection.This information, required by the very nature of the theoryitself, includes knowing the pattern of heredity of the phenotypiccharacters being studied, relating intrapopulational phenotypicvariability to variation in fitness, and knowing a sufficientamount about population structure to specify the componentsof natural selection. Studies within functional evolutionarymorphology are not designed to satisfy these requirements. Functionalevolutionary morphology uses the concepts of adaptation andnatural selection axiomatically, and thus such studies contributenothing to our understanding of the evolutionary process becausehypotheses about that process are not being evaluated. Thisalso suggests that, if functional evolutionary morphology wishesto engage in analyses of the evolutionary dynamics of the phenotype,a reorientation of its research strategy and goals will be necessary. 相似文献
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Japanese encephalitis virus (JEV) is a zoonotic pathogen transmitted by the infectious bite of Culex mosquitoes. The virus causes the development of the disease Japanese encephalitis (JE) in a small proportion of those infected, predominantly affecting children in eastern and southern Asia. Annual JE incidence estimates range from 50,000–175,000, with 25%–30% of cases resulting in mortality. It is estimated that 3 billion people live in countries in which JEV is endemic. The virus exists in an enzootic transmission cycle, with mosquitoes transmitting JEV between birds as reservoir hosts and pigs as amplifying hosts. Zoonotic infection occurs as a result of spillover events from the main transmission cycle. The reservoir avian hosts include cattle egrets, pond herons, and other species of water birds belonging to the family Ardeidae. Irrigated rice fields provide an ideal breeding ground for mosquitoes and attract migratory birds, maintaining the transmission of JEV. Although multiple vaccines have been developed for JEV, they are expensive and require multiple doses to maintain efficacy and immunity. As humans are a “dead-end” host for the virus, vaccination of the human population is unlikely to result in eradication. Therefore, vector control of the principal mosquito vector, Culex tritaeniorhynchus, represents a more promising strategy for reducing transmission. Current vector control strategies include intermittent irrigation of rice fields and space spraying of insecticides during outbreaks. However, Cx. Tritaeniorhynchus is subject to heavy exposure to pesticides in rice fields, and as a result, insecticide resistance has developed. In recent years, significant advancements have been made in the potential use of the bacterial endosymbiont Wolbachia for mosquito biocontrol. The successful transinfection of Wolbachia strains from Drosophila flies to Aedes (Stegomyia) mosquitoes has resulted in the generation of “dengue-refractory” mosquito lines. The successful establishment of Wolbachia in wild Aedes aegypti populations has recently been demonstrated, and open releases in dengue-endemic countries are ongoing. This review outlines the current control methods for JEV in addition to highlighting the potential use of Wolbachia-based biocontrol strategies to impact transmission. JEV and dengue virus are both members of the Flavivirus genus, and the successful establishment of Drosophila Wolbachia strains in Cx. Tritaeniorhynchus, as the principal vector of JEV, is predicted to significantly impact JEV transmission. 相似文献
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E. M. Kazin E. A. Anisova A. R. Galeev I. L. Golenda E. S. Gol'dshmidt K. V. Grishina R. G. Drapezo L. N. Igisheva V. V. Minin O. V. Ovchinnikova S. V. Shabasheva 《Human physiology》2001,27(2):228-238
By means of a complex of cost-effective, rapid, and, whenever possible, computerized screening procedures, a systematic two-week study period of the functional states of subjects in a small group of healthy adults was performed. The daily variations of 125 parameters and periodic changes in 51 parameters of somatic and mental health were investigated at increasing doses of an adaptive drug. In the initial state of the subjects, various deviations of the somatic parameters from the normal level were found, presumably of a nutritional origin. The adaptive drug was found to normalize the changed parameters of somatic health within a week due to a strain in the regulatory systems and a decline in the functional reserves of adaptation. At the end of the examination, excessive doses of the adaptive drug returned the majority of the somatic parameters to the initial levels. At the same time, the work capacity of the subjects decreased and the strain on the autonomic nervous system and the level of stress increased. Discomfort and fatigue developed, which restricted the abilities of the examined subjects to choose behavioral tactics. 相似文献
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A survey of herbivores of Striga hermonthica Del. Benth., a root parasite of cereal crops, was conducted in northern Ghana in 1992. Smicronyx umbrinus Hustache (Coleoptera: Curculionidae) and Junonia orithya L. (Lepidoptera: Nymphalidae) were found to attack S. hermonthica in all areas surveyed. Preliminary observations indicate that these two insects have a great potential to cause damage. In the Shinyanga region of Tanzania, Malawi and the middle-west of Madagascar, investigations revealed that only J. orithya is common in all areas surveyed, in contrast to the situation in northern Ghana. 相似文献
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Sperm competition arises as a result of complex interactions among male and female factors. While the roles of some male factors are known, little is known of the molecules or mechanisms that underlie the female contribution to sperm competition. The genetic tools available for Drosophila allow us to identify, in an unbiased manner, candidate female genes that are critical for mediating sperm competition outcomes. We first screened for differences in female sperm storage and use patterns by characterizing the natural variation in sperm competition in a set of 39 lines from the sequenced Drosophila Genetic Reference Panel (DGRP) of wild-derived inbred lines. We found extensive female variation in sperm competition outcomes. To generate a list of candidate female genes for functional studies, we performed a genome-wide association mapping, utilizing the common single-nucleotide polymorphisms (SNPs) segregating in the DGRP lines. Surprisingly, SNPs within ion channel genes and other genes with roles in the nervous system were among the top associated SNPs. Knockdown studies of three candidate genes (para, Rab2, and Rim) in sensory neurons innervating the female reproductive tract indicate that some of these candidate female genes may affect sperm competition by modulating the neural input of these sensory neurons to the female reproductive tract. More extensive functional studies are needed to elucidate the exact role of all these candidate female genes in sperm competition. Nevertheless, the female nervous system appears to have a previously unappreciated role in sperm competition. Our results indicate that the study of female control of sperm competition should not be limited to female reproductive tract-specific genes, but should focus also on diverse biological pathways. 相似文献
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抗生素2,4-二乙酰基间苯三酚作为荧光假单胞菌2P24菌株生防功能因子的实证分析 总被引:12,自引:2,他引:12
荧光假单胞杆菌2P24菌株分离自小麦全蚀病自然衰退土壤,它是酚类抗生素2,4-二乙酰基间苯三酚(2,4-DAPG)的高产菌,对多种土传病害具有较好的防治能力。利用同源重组构建2,4-DAPG合成基因的定位突变体,并对突变体进行基因互补,通过检测突变菌株和恢复突变菌株抗生素产量和生防效果确定2,4-DAPG在菌株2P24生防功能中的作用。实验中,定位突变体丧失产生抗生素和拮抗病原菌的能力,而恢复突变体的抗生素产量和拮抗能力均恢复至野生菌水平。在对番茄青枯病的防病试验中,2,4-DAPG突变体的防效低且下降快,而恢复突变体的生防能力与野生菌相当,且效果稳定。由此可确定2,4-DAPG是菌株2P24防治番茄青枯病的主要因子,在防效上起关键作用。 相似文献
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In otological and ophthalmological functional diagnostics it is typical to record for a certain individual several similar biopotentials under different conditions of stimulation and/or to collect various potentials for the same individual. Since the combination of these different data collected from a patient is of interest, coupling of the classification results obtained for each single data set seems desirable. Based on sample classifiers, obtained by linear discriminance analysis, of acoustically or visually evoked potentials from selected patients an algorithm is proposed for their coupling, which logically links the various rules of allocation and is based on the principle of assignment by highest likelihood. Furthermore, the procedure may be modified by inclusion of corresponding confidence intervals for the determined allocation frequencies. The results obtained for the groups of patients investigated show a considerable improvement of classification as judged from the error rates being distinctly reduced after the coupling. 相似文献
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Application of the method of arterial piezopulsometry to studying the individual characteristics of the functional state of the cardiovascular system (CVS) in patients of different ages and health states is discussed. Development of a new algorithm for the two-channel simultaneous analysis of the parameters of blood pressure pulse wave plots recorded by two piezoelectric transducers has allowed us to perform a comparative analysis of cardiohemodynamics in different arteries, as well as to evaluate the elasticity of their walls and the nature of the autonomic regulation of CVS effectors with high accuracy. This comprehensive analysis enhances the predictive value of early pulsometric diagnostics of the individual functional state of CVS in humans. 相似文献
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Background
Transient ischemic attack (TIA) is usually defined as a neurologic ischemic disorder without permanent cerebral infarction. Studies have showed that patients with TIA can have lasting cognitive functional impairment. Inherent brain activity in the resting state is spatially organized in a set of specific coherent patterns named resting state networks (RSNs), which epitomize the functional architecture of memory, language, attention, visual, auditory and somato-motor networks. Here, we aimed to detect differences in RSNs between TIA patients and healthy controls (HCs).Methods
Twenty one TIA patients suffered an ischemic event and 21 matched HCs were enrolled in the study. All subjects were investigated using cognitive tests, psychiatric tests and functional magnetic resonance imaging (fMRI). Independent component analysis (ICA) was adopted to acquire the eight brain RSNs. Then one-sample t-tests were calculated in each group to gather the spatial maps of each RSNs, followed by second level analysis to investigate statistical differences on RSNs between twenty one TIA patients and 21 controls. Furthermore, a correlation analysis was performed to explore the relationship between functional connectivity (FC) and cognitive and psychiatric scales in TIA group.Results
Compared with the controls, TIA patients exhibited both decreased and increased functional connectivity in default mode network (DMN) and self-referential network (SRN), and decreased functional connectivity in dorsal attention network (DAN), central-executive network (CEN), core network (CN), somato-motor network (SMN), visual network (VN) and auditory network (AN). There was no correlation between neuropsychological scores and functional connectivity in regions of RSNs.Conclusions
We observed selective impairments of RSN intrinsic FC in TIA patients, whose all eight RSNs had aberrant functional connectivity. These changes indicate that TIA is a disease with widely abnormal brain networks. Our results might put forward a novel way to look into neuro-pathophysiological mechanisms in TIA patients. 相似文献15.
The authors consider an insufficiently studied indicator, i.e., motor activity of eyelids, recorded with or without miniature contacts in infrared rays for the visual analyzer states eyes open / eyes closed. Eyelid movement characteristics are highly informative in diagnosing the functional state and evaluating operator activity quality under monotonous conditions. The authors discuss possible mechanisms of the influence of such functional states on the motor activity of eyelids. 相似文献
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Seed treatments containing combinations of Escherichia coli S17R1 and Burkholderia cepacia Bc-B provided significantly greater (P ≤ 0.05) suppression of cucumber seedling pathogens in a field soil naturally infested with Pythium and Fusarium spp. than seeds treated individually with strains Bc-B, S17R1, or Enterobacter cloacae 501R3. Although strain S17R1 had no effect on disease severity when applied alone and did not colonize cucumber rhizosphere, it enhanced the biocontrol effectiveness of strain Bc-B. 相似文献
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Marco Janssen 《Ecosystems》1998,1(5):457-463
Global modeling has been used for decades to assess the possible futures of humanity and the global environment. However, these models do not always satisfactorily include the adaptive characteristics of systems. In this article, a general approach is used to simulate change and transition at a macrolevel due to adaptation at a microlevel. Tools from complex adaptive systems research are used to simulate the microlevel and consequently determine parameter values of the equation-based macrolevel model. Two case studies that applied this approach are reviewed. The first study assessed the efficacy of efforts to control malaria, whereas the second study used an integrated model to construct climate change scenarios by using various possible views on the nature of the climate system. Received 14 April 1998; accepted 7 July 1998. 相似文献
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Parameters of cardiorespiratory synchronization were determined in children with different types of nervous system, under conditions of psychoemotional stress and in gastrobiliary disease. These parameters were found to be significant in characterizing the regulatory and adaptive potential of children. 相似文献
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Current and Future Use of Nematodes in Biocontrol: Practice and Commercial Aspects with Regard to Regulatory Policy Issues 总被引:1,自引:0,他引:1
Ralf-Udo Ehlers 《Biocontrol Science and Technology》1996,6(3):303-316
Constraints about the use of chemical insecticides have limited the availability of control measures against soil-borne insect pests. Entomopathogenic nematodes of the genera Steinernema and Heterorhabditis provide an environmentally safe and economically reasonable alternative. Their life cycle and current production, storage and formulation technology are described. An overview of their safety, use in integrated pest management and current market potential (US$10 million in 1994) is also given. The costs of research and development efforts and the scale-up of production technologies are discussed in relation to the current and future market potential. Large-scale, outdoor application will require additional scientific and technical progress in the areas of production, storage, formulation and application. Besides public funding, the current niche markets will need to provide the financial basis for further development, provided that regulatory conditions will not limit the exploitation of the nematodes' market potential. It is recommended that nematodes should be exempted from registration. Rules for risk assessment in the use of exotic nematodes should be internationally harmonized and related specifically to the biology and ecology of these nematodes. The volume of current markets would not justify the costs of registration procedures currently required for chemical or microbial insecticides or genetically engineered organisms. Regulatory policies should aim at supporting the further introduction of entomopathogenic nematodes as biocontrol agents. 相似文献