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Current status of antisense DNA methods in behavioral studies   总被引:4,自引:0,他引:4  
Ogawa  S; Pfaff  DW 《Chemical senses》1998,23(2):249-255
The antisense DNA method has been used successfully to block the expression of specific genes in vivo in neuronal systems. An increasing number of studies in the last few years have shown that antisense DNA administered directly into the brain can modify various kinds of behaviors. These findings strongly suggest that the antisense DNA method can be used as a powerful tool to study causal relationships between molecular processes in the brain and behavior. In this article we review the current status of the antisense method in behavioral studies and discuss its potentials and problems by focusing on the following four aspects; (i) optimal application paradigms of antisense DNA methods in behavioral studies; (ii) efficiencies of different administration methods of antisense DNA used in behavioral studies; (iii) determination of specificity of behavioral effects of antisense DNA; and (iv) discrepancies between antisense DNA effects on behaviors and those on protein levels of the targeted gene.   相似文献   
3.

Background

A new subgroup of HIV-1, designated Group P, was recently detected in two unrelated patients of Cameroonian origin. HIV-1 Group P phylogenetically clusters with SIVgor suggesting that it is the result of a cross-species transmission from gorillas. Until today, HIV-1 Group P has only been detected in two patients, and its degree of adaptation to the human host is largely unknown. Previous data have shown that pandemic HIV-1 Group M, but not non-pandemic Group O or rare Group N viruses, efficiently antagonize the human orthologue of the restriction factor tetherin (BST-2, HM1.24, CD317) suggesting that primate lentiviruses may have to gain anti-tetherin activity for efficient spread in the human population. Thus far, three SIV/HIV gene products (vpu, nef and env) are known to have the potential to counteract primate tetherin proteins, often in a species-specific manner. Here, we examined how long Group P may have been circulating in humans and determined its capability to antagonize human tetherin as an indicator of adaptation to humans.

Results

Our data suggest that HIV-1 Group P entered the human population between 1845 and 1989. Vpu, Env and Nef proteins from both Group P viruses failed to counteract human or gorilla tetherin to promote efficient release of HIV-1 virions, although both Group P Nef proteins moderately downmodulated gorilla tetherin from the cell surface. Notably, Vpu, Env and Nef alleles from the two HIV-1 P strains were all able to reduce CD4 cell surface expression.

Conclusions

Our analyses of the two reported HIV-1 Group P viruses suggest that zoonosis occurred in the last 170 years and further support that pandemic HIV-1 Group M strains are better adapted to humans than non-pandemic or rare Group O, N and P viruses. The inability to antagonize human tetherin may potentially explain the limited spread of HIV-1 Group P in the human population.  相似文献   
4.
Abstract: We tested the hypothesis that piping plover (Charadrius melodus) habitat quality and chick survival on the Missouri River, USA, were lower on a cold-water reservoir and downstream from a hypolimnetic (cold-water) release dam with diel water fluctuations (Garrison Dam) than downstream from an epilimnetic dam (Gavins Point Dam). Plovers in adjacent alkali wetlands provided an index to the maximum reproductive potential in the region. Chicks gained weight more rapidly in the alkali wetlands than on epilimnetic and hypolimnetic river reaches. Invertebrate numbers and biomass were higher in the wetlands and epilimnetic reach, but chick survival was lower on the epilimnetic reach. Thus, piping plovers adapted to a variety of prey densities, and other factors, likely predation, reduced survival rates in the epilimnetic reach. Temporal and spatial variability in site quality indices suggests the need for a regional management strategy with different strategies at each site. Managers can minimize effects of local fluctuations in resource abundance and predators by ensuring protection of or creating geographically dispersed habitat. (JOURNAL OF WILDLIFE MANAGEMENT 72(3):682–687; 2008)  相似文献   
5.
The morphospace of 54 species of Commelinaceae from nine genera was examined with simultaneous attention to constraints, adaptive hypotheses and relatedness. Eleven morphological traits, including leaf length and width, angle between the leaves and internode distances, were measured for each species and analysed by principal components analysis and nested analysis of variance. The results revealed a significant signal of relatedness in vegetative morphology; genus explained 20–50% of the variance in a single trait. The relationships between some traits are consistent with adaptive explanations. The findings are consistent with the prediction that evolution for optimal phyllotaxis should be relaxed as self‐shading decreases, and that light availability governs leaf size and branching patterns. Constraints potentially explain some trait correlations, and support was found for the hypothesis that structural constraints govern leaf size and internode size correlations. © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society, 2008, 158 , 257–268.  相似文献   
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L-Lactate dehydrogenase (L-LDH, E.C. 1.1.1.27) is encoded by two or three loci in all vertebrates examined, with the exception of lampreys, which have a single LDH locus. Biochemical characterizations of LDH proteins have suggested that a gene duplication early in vertebrate evolution gave rise to Ldh-A and Ldh-B and that an additional locus, Ldh-C arose in a number of lineages more recently. Although some phylogenetic studies of LDH protein sequences have supported this pattern of gene duplication, others have contradicted it. In particular, a number of studies have suggested that Ldh-C represents the earliest divergence among vertebrate LDHs and that it may have diverged from the other loci well before the origin of vertebrates. Such hypotheses make explicit statements about the relationship of vertebrate and invertebrate LDHs, but to date, no closely related invertebrate LDH sequences have been available for comparison. We have attempted to provide further data on the timing of gene duplications leading to multiple vertebrate LDHs by determining the cDNA sequence of the LDH of the tunicate Styela plicata. Phylogenetic analyses of this and other LDH sequences provide strong support for the duplications giving rise to multiple vertebrate LDHs having occurred after vertebrates diverged from tunicates. The timing of these LDH duplications is consistent with data from a number of other gene families suggesting widespread gene duplication near the origin of vertebrates. With respect to the relationships among vertebrate LDHs, our data are not consistent with previous claims that Ldh-C represented the earliest divergence. However, the precise relationships among some of the main lineages of vertebrate LDHs were not resolved in our analyses.   相似文献   
8.
Biophysical Ecology and Heat Exchange in Insects   总被引:2,自引:1,他引:1  
When used with observations of behavior and physiology of animalsin known microclimates, a biophysical approach is a powerfultool for predicting body temperatures of insects. For ectothermicinsects, solution of the energy budget equation and use of operativetemperature models have been used to determine the range oftemperatures which an insect can exhibit in a given environment.Knowledge of body temperature has allowed predictions of whenimportant behaviors arepossible in the field, thereby directlyrelating biophysical models to fitness parameters of animals.A proper understanding of the physiological mechanism(s) controllingheat exchange is prerequisite to application and interpretationof information obtained using biophysical techniques. For endothermicinsects, physiological regulation of heat exchange forces amore complicated analysis. Evaluation of thoracic heat exchangealone (aside from indicating whether insects are regulatingTth) is of little utility for either quantifying total heatexchange, or evaluating thermoregulatory mechanisms withoutfurther information. Further studies of biophysics and physiologyof endothermic insects during flight are needed to correct thesedeficiencies. Application of biophysical techniques has allowedpredictions of behavior of flying insects based onprinciplesof heat exchange which cannot be examined directly. Analysesof endothermy of restinghoneybee swarms and hives indicate thatthese "superorganisms" regulate temperature rather preciselyover a remarkable range of environmental temperature using mechanismsequivalent to thoseused by resting endothermic vertebrates.  相似文献   
9.
In two cases of "lower nephron nephrosis" or acute renal failure, needle biopsies of the kidney were performed. The first case developed in a 46-year-old woman following inhalation of vapors from an insecticide spray and a cleaning fluid. The second case was due to ingestion of carbon tetrachloride. Histologic study of the human kidney during toxic nephrosis showed changes confined mainly to the epithelium of the proximal tubules, confirmed the diagnosis, and illuminated the clinical course. Needle biopsy of the kidney during acute renal failure did not influence the course of the disease unfavorably. It was easy, and entailed no complications. Needle biopsy of kidneys may prove as informative and valuable as needle biopsies of the liver by aiding in the prognosis as well as in the diagnosis of various renal diseases.  相似文献   
10.
Weekly observations were made of the South Winterbourne from October 1970 to December 1971. Flow commenced in November 1970 and ceased in July 1971, a maximum flow of 1.51 m3 s?1 being recorded in January 1971. The chemical composition was not very variable, but nitrate showed a positive correlation with flow.  相似文献   
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