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PubMed1992

Husbandry, reproduction and postnatal development of the neotropical muroid rodent Zygodontomys brevicauda.

Laboratory colonies of the Neotropical muroid rodent Zygodontomys brevicauda have been employed in studies of arbovirus epidemiology and are currently the subjects of experimental research on tropical mammalian reproductive physiology and evolutionary quantitative genetics. Captive-bred litters typically consist of 4 or 5 pups weighing 3-4 g each at birth. Adults 20-40 weeks old average 60-80 g with some sexual dimorphism. Females are sexually mature at 3-4 weeks of age, males at 6-8 weeks. Ovulation is spontaneous and gestation is 25 days. Preliminary observations are provided on the microbiological status and parasites of captive-bred animals.

Animal Husbandry↗
PubMed2006

Dynamics of gene introgression in the African malaria vector Anopheles gambiae.

Anopheles gambiae is a major malaria vector in Africa and a popular model species for a variety of ecological, evolutionary, and genetic studies on vector control. Genetic manipulation of mosquito vectorial capacity is a promising new weapon for the control of malaria. However, the release of exotic transgenic mosquitoes will bring in novel alleles in addition to the parasite-inhibiting genes, which may have unknown effects on the local population. Therefore, it is necessary to develop methodologies that can be used to evaluate the spread rate of introduced genes in A. gambiae. In this study, the effects and dynamics of genetic introgression between two geographically distinct A. gambiae populations from western Kenya (Mbita) and eastern Tanzania (Ifakara) were investigated with amplified fragment length polymorphisms (AFLPs) and microsatellite markers. Microsatellites and polymorphic cDNA markers revealed a large genetic differentiation between the two populations (average F(ST) = 0.093, P < 0.001). When the two strains were crossed in random mating between the two populations, significant differences in the rate of genetic introgression were found in the mixed populations. Allele frequencies of 18 AFLP markers (64.3%) for Mbita and of 26 markers (92.9%) for Ifakara varied significantly from F5 to F20. This study provides basic information on how a mosquito release program would alter the genetic makeup of natural populations, which is critical for pilot field testing and ecological risk evaluation of transgenic mosquitoes.

Animals↗
PubMed2002

Transposable elements in medaka fish.

DNA-based transposable elements appear to have been nearly or completely inactivated in vertebrates. Therefore the elements of the medaka fish Oryzias latipes that still have transposition activity provide precious materials for studying transposition mechanisms, as well as the evolution, of transposable elements in vertebrates. Fortunately, the medaka fish has a strong background for genetic and evolutionary studies. The advantages of this host species and their elements, together with results so far obtained, are here described.

Animals↗
PubMed2005

Angiotensin antagonism in coronary artery disease: results after coronary revascularisation.

The renin-angiotensin system (RAS) is an ancient and complex cascade of homeostatic reactions aimed at regulating primordial functions that ensure organ perfusion through the control of blood pressure and the regulation of renal-cardiac activity. However, the over-expression or lack of compensatory mechanisms of any of its components may initiate detrimental effects that potentially lead to disease, a balance that makes the RAS a sequence with a labile physiological equilibrium and with a strong harm potential. These characteristics of the RAS in general, and of the angiotensin converting enzyme (ACE) in particular, make it not only an important complex for the regulation of blood pressure and neuropeptide metabolism, but also a fascinating subject of study from a biochemical, evolutionary and genetic point of view. Pharmacological interventions that influence the RAS by inhibiting the ACE or the angiotensin II type 1 receptor (AT1R) have demonstrated sustained efficacy in reducing the incidence of cardiovascular events and, consequently, vascular mortality in several clinical situations. ACE inhibitors and angiotensin II receptor antagonists (ARAs) reduce blood pressure and have cardio- and vasculoprotective effects. Anti-atherosclerotic effects have also been attributed to these drugs. For these reasons, it has been hypothesised that RAS inhibitors could also reduce the recurrence of ischaemic events after myocardial revascularisation procedures, namely coronary artery by-pass graft surgery (CABG) or percutaneous coronary interventions (PCI). Information available on the effect of ACE inhibitors and ARAs in patients with coronary artery disease (CAD) previously treated with revascularisation techniques indicates a substantial reduction of mortality and infarction in these patients. However, data regarding the progression of CAD, restenosis or reocclusion of vascular conduits of the coronary circulation after myocardial revascularisation are inconsistent. In most studies, the administration of ACE inhibitors neither improved the ischaemic threshold nor reduced the need for new revascularisation procedures. On the contrary, ACE inhibitors have been associated with higher restenosis rates after PCI in some retrospective series. Conversely, a single, exploratory randomised trial demonstrated that the selective AT1R antagonist valsartan significantly reduced stent restenosis after PCI. In patients undergoing CABG, ACE inhibitors did not reduce the risk of graft degeneration or occlusion. Studies that evaluated a possible anti-atherosclerotic effect of ACE inhibitors (including some large randomised trials) have generally been negative.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed2006

The pharmacology of ageing in Drosophila.

Recent research indicates that aging is affected by many genes and thus many biochemical pathways. This has led to a failure to find pharmaceuticals that significantly ameliorate the human aging process. Progress in evolutionary and genetic research, however, suggests the possibility of combining experimental evolution, genomic analysis, and mass screening of pharmaceuticals and botanicals to produce effective therapeutics for human aging. The starting point for this strategy is model systems that have outbred populations with substantially increased lifespan. These are easily produced by tuning the force of natural selection in the laboratory. Such biological material is then a good candidate for genomic analysis, leading to the identification of numerous biochemical pathways involved in increased lifespan, in the model system. These biochemical pathways would then be available for pharmaceutical development, first in fruit flies, then in rodents, and eventually in a clinical human population. We include a discussion of the pharmacological methods appropriate to this strategy of drug discovery.

Aging↗
PubMed1986

Genes for cytochrome P-450 and their regulation.

The capacity of the liver microsomal mixed-function oxidase system to metabolize a wide variety of exogenous as well as endogenous compounds reflects the participation of multiple forms of the terminal oxidase, cytochrome P-450, which have different broad, but overlapping, substrate specificities. Several of these isozymes accumulate in the liver after exposure of animals to specific inducing agents. Recent studies employing recombinant DNA techniques to investigate the genetic and evolutionary relatedness of various cytochrome P-450 isozymes as well as the molecular basis for the induction phenomenon are described. The conclusions from these investigations are presented in the context of the substantial body of data obtained from the characterization of specific cytochrome P-450 isozymes and from studies on the induction of specific isozymes or enzymatic activities during development or after treatment of animals with various inducing agents.

Amino Acid Sequence↗
PubMed1997

Cut and die: proteolytic cascades regulating apoptosis.

Cell death by apoptosis is an amazing mechanism which plays a primary function in governing both development and tissue homeostasis in multicellular organisms. Different cells, from nematodes to humans, utilize the same evolutionary conserved genetic program controlling apoptosis. The key event in the execution of the suicide program is the activation of specific proteases belonging to the caspase family (cysteine protease specific for aspartic residues). Following their activation, caspases process key substrates which probably orchestrate the complex cellular changes that mark apoptosis. This review will focus on the recent advances in our understanding of the proteolytic events regulating apoptosis.

Journal Article↗
PubMed1999

Going to extremes: family structure, children's well-being, and social science.

In this article I argue that public discussions of demographic issues are often conducted in a troubling pattern in which one extreme position is debated in relation to the opposite extreme. This pattern impedes our understanding of social problems and is a poor guide to sound public policies. To illustrate this thesis I use the case of social scientific research examining how children are affected by not living with two biological parents while they are growing up. Over the last decade, I maintain, most of the public, and even many social scientists, have been puzzled and poorly informed by this debate. In particular I consider Judith Wallerstein's clinically based claims of the pervasive, profound harm caused by divorce and, at the other extreme, Judith Rich Harris's reading of behavioral genetics and evolutionary psychology, which leads her to dismiss the direct effects of divorce. Neither extreme gives a clear picture of the consequences of growing up in a single-parent family or a stepfamily.

Child↗
PubMed2000

Evolutionary ecology of Datura stramonium: genetic variation and costs for tolerance to defoliation.

The incorporation of plant tolerance after damage as a new alternative to cope with herbivory, as opposed to resistance, opened new avenues for our understanding of coevolution between plants and herbivores. Although genetic variation on tolerance to defoliation has been detected in some species, few studies have been undertaken with nonagricultural species. In this study, we explore in the annual weed Datura stramonium the existence of genetic variation for tolerance and fitness costs of tolerance. To determine which fitness-related trait was responsible for possible differences in tolerance, growth rate, total flower and fruit production, and the number of seeds per fruit were recorded. Inbred line replicates of D. stramonium from a population of Mexico City were exposed to four defoliation levels (0%, 10%, 30%, and 70%). Our results from a greenhouse experiment using controlled genetic material (inbred lines) indicated that significant genetic variation for tolerance was detected across defoliation environments. Defoliation reduced plant fitness from 15% to 25% in the highest levels of defoliation. Differences on tolerance among inbred lines were accounted by a differential reduction in the proportion of matured fruits across defoliation levels (up to 20%). Within defoliation levels, significant genetic variation in plant fitness suggests that tolerance could be selected. The correlation between fitness values of inbred lines in two environments (with and without damage) was positive (rg = 0.77), but not significant, suggesting absence of fitness costs for tolerance. The finding of genetic variation on tolerance might be either due to differences among inbred lines in their capability to overcome foliar damage through compensation or due to costs incurred by inducing secondary metabolites. Our results indicate the potential for norms of reaction to be selected under a gradient of herbivory pressure and highlights the importance of dissecting induced from compensatory responses when searching for potential causes of genetic variation on tolerance.

Environment↗
PubMed1963

MOSQUITO CYTOGENETICS. A REVIEW OF THE LITERATURE, 1953-62.

Although an intensified interest in mosquito cytogenetics in the past decade has produced a number of contributions to knowledge on this subject, the available information is still superficial and limited to a few mosquito species only. The author of this review summarizes the research done in this field between 1953 and 1962.The following are some of the achievements and some of the gaps that remain to be filled. Karyotypes of several species of Anopheles, Aedes and Culex conform to the general pattern 2n=6, with heterosomes distinguishable only in Anopheles. At least three different karyotypes are present in Anopheles. Salivary gland chromosome maps are now available for several anopheline species, but are still lacking for Culex and Aedes. No precise correlation may yet be made between the frequency of chromosomal aberrations and the degree of insecticide-resistance. Sexual differences in the salivary X-chromosomes have been reported for several species of Anopheles. Chromosomal polymorphism is common in some anophelines, but rare in others. Chromosomal mutation has been induced by means of X-rays.In his conclusions, the author stresses that prospects are especially good for evolutionary and genetic studies involving chromosomal polymorphism.

Aedes↗
PubMed2006

[Application of modern molecular biology techniques to study micro-ecosystem in the rumen].

The microbial community inhabiting in the rumen is characterized by its high population density, wide diversity and interactive complexity. However, until recently our knowledge of rumen microbiology was primarily based on classical culture based techniques (isolation, enumeration and nutritional characterization) which probably only account for 10% to 20% of the rumen microbial population. Modem molecular biology techniques provide effective methods to study the micro-ecosystem in the rumen. The use of molecular techniques based on nucleic acid probes is likely to revolutionize the approach to microbial ecology in the rumen and provide, not simply a refinement or increased understanding but a complete description of rumen community for the first time. Modem molecular techniques based on sequence comparisons of nucleic acids may be used to explore molecular characterization and provide a classification scheme which predicts natural evolutionary relationships. Genetic fingerprinting techniques that provide a pattern or profile of genetic diversity have been applied in a variety of environmental studies for the analysis of microbial communities. Whole-cell hybridization is a powerful technique which may be used to study the structure and function of microbial communities in situ and describe the expression of key enzymes. Real-time quantitative PCR technique may be conducted to accurately quantify the target microorganisms in the rumen. Development of these procedures and techniques will result in greater insights into community structure and activity of rumen microbial communities in relation to functional interactions, spatial and temporal relationships between different microorganisms and between microorganisms and feed particles. The successful development and application of these methods promise to provide the first opportunity to link distribution and identity of rumen microbes in their natural environment with their genetic potential and in situ activities.

Animals↗
PubMed1982

Haemaphysalis (Garnhamphysalis) mjoebergi: identity, structural variation and biosystematic implications, deer hosts, and distribution in Borneo and Sumatra (Ixodoidea: Ixodidae).

Haemaphysalis (Garnhamphysalis) mjoebergi Warburton was reported from four male specimens from Sarawak, Borneo. We redescribe herein the male, from three specimens from Sarawak and 24 from Lampung District, Sumatra, and describe the female from 24 specimens from Lampung. Male structural variation in the dental formula and development of the coxa IV spur and segments of legs III and IV is unusual or unique in the genus Haemaphysalis. "Atypical" males might easily be misidentified. This species provides an ideal model for experimental study of population genetics and evolutionary processes and of biological factors influencing body size and structural variation in the genus Haemaphysalis. The sambar deer, Cervus unicolor brookei Hose (Sarawak) and C. unicolor equinus Cuvier (Sumatra), appears to be the chief host in humid, marshy, lowland forests and secondary growth. Single collections were from a human and a domestic cow. The dynamics and vector potential of this tick should be investigated in environments being exploited for human settlement and cattle breeding.

Animals↗
PubMed1981

[Anthropological aspects of behavioural development (author's transl)].

Resulting from psychological, evolutionary and genetical aspects of behavioural development it is attempted go more fully into extent and significance of anthropological researches analysing the conditions of behaviour, particularly by motor development. So the general assertion will be more exact that all anthropological researches applied to structural and functional fundamentals of man are important for analysis of behaviour, its variability, its variability and development too.

Anthropology↗
PubMed1997

[Behavior and evolution].

Main works of D.K. Belyaev on genetic and evolutionary aspects of behavior are reviewed. Principal trends in development of this problem in modern science are considered. The role of Darwinian evolution in formation of human and animal behavior and evolutionary significance of behavior are discussed.

Animals↗
PubMed2004

HERG binding specificity and binding site structure: evidence from a fragment-based evolutionary computing SAR study.

We describe the application of genetic programming, an evolutionary computing method, to predicting whether small molecules will block the HERG cardiac potassium channel. Models based on a molecular fragment-based descriptor set achieve an accuracy of 85-90% in predicting whether the IC(50) of a 'blind' set of compounds is <1 microM. Analysis of the models provides a 'meta-SAR', which predicts a pharmacophore of two hydrophobic features, one preferably aromatic and one preferably nitrogen-containing, with a protonatable nitrogen asymmetrically situated between them. Our experience of the approach suggests that it is robust, and requires limited scientist input to generate valuable predictive results and structural understanding of the target.

Animals↗