Endophenotypes as a measure of suicidality

Suicide is thought to result from the harmful interaction of multiple factors that have social, environmental, neurobiological, and genetic backgrounds. Recent studies have suggested that genetic predisposition to suicidal behavior may be independent of the risk of suicide associated to mental disorders, such as affective disorders, schizophrenia, or alcohol dependence. Given the suicidal behavior heterogeneity and its hereditary complexity, the need to find demonstrable intermediate phenotypes that may make it possible to establish links between genes and suicide behaviors (endophenotypes) seems to be necessary. The main objective of this review was to consider the candidate endophenotypes of suicidal behaviors. Due to the recent advances in neuroimaging, we also characterize brain regions implicated in vulnerability to suicide behavior that are influenced by gene polymorphisms associated with suicidal behavior.     

CTLA4 gene polymorphisms are associated with, and linked to, insulin-dependent diabetes mellitus in a Russian population

Background  

The association between the human cytotoxic T lymphocyte-associated antigen-4 (CTLA4) gene and insulin-dependent diabetes mellitus (IDDM) is unclear in populations. We therefore investigated whether the gene conferred susceptibility to IDDM in a Russian population. We studied two polymorphic regions of the CTLA4 gene, the codon 17 dimorphism and the (AT)_n microsatellite marker in the 3' untranslated region in 56 discordant sibling pairs and in 33 identical by descent (IBD) affected sibships.     

Polymorphism of gene encoding vascular angiotensin II receptor and microangiopathies in patients with insulin-dependent diabetes mellitus

Polymorphism A1166C of the AT1R gene encoding angiotensin vascular receptor [replacement of C (cytosine) for A (adenine)) at position 1166] was compared in patients with insulin-dependent diabetes mellitus (IDDM) complicated by diabetic nephropathy (DN) and in noncomplicated patients (n = 27 and n = 41, respectively) and also in patients with IDDM complicated by diabetic retinopathy (DR) and in correspondent noncomplicated individuals (n = 30 and n = 44, respectively). The frequency of AT1R gene alleles and genotypes in patients with IDDM complicated by DN did not differ significantly from that observed in patients with noncomplicated IDDM. In contrast, in patients with IDDM complicated by retinopathy, a significant decrease in the content of A allele (68.3% against 82.6%) and a significant increase in the content of C allele (31.7% against 17.4%) was found as compared with the control group. Thus, in the Moscow population, A1166C polymorphism of the AT1R gene is not associated with diabetic renal complications but indeed associated with diabetic retinal complications. C allele is a risk factor of DR (the relative risk, RR, is equal to 2.17), and A allele is, in contrast, a protective factor against early retinopathy development (RR is equal to 0.49).     

Analysis of polymorphism of the D11S2008 locus of the catalase gene in patients with hypertension and ischemic heart disease in non-insulin-dependent diabetes mellitus in the Muscovite population

The allele and genotype frequency distributions of the D11S2008 tetranucleotide microsatellite linked with the catalase (CAT) gene were compared between patients with insulin-dependent diabetes mellitus (IDDM) with (N = 72) and without (N = 82) coronary heart disease (CHD), and between IDDM patients with normal arterial tension (N = 82) and with arterial hypertension (N = 42). In total, eight alleles were found. The alleles varied in length from 120 to 148 bp and included from 15 to 22 tetranucleotide repeats. The groups did not differ in D11S2008 allele and genotype frequencies; the only exception was that the frequency of genotype 18/19 in patients with CHD (31.9%) was significantly higher than in the controls (18.3%). Thus, the D11S2008 polymorphic locus located in proximity to the catalase gene proved to be weakly associated with CHD, but not associated with arterial hypertension, in IDDM patients. Genotype 18/19 was associated with a higher risk of CHD.     

马占相思林冠蜘蛛群落的结构分析

用杀灭菊酯喷洒林冠,收集得蜘蛛２６种,１９９只。群落组成以不结网为为主,全年均保持较高数量水平。结网类从４月至１０月成指数曲数下降。４个相似样地上的群落结构显著差异。以ＭａｃＡｒｔｈａｒ分布模型为基础,求出每个种在群落中的数量－时间－空间的重要值。结果以斜蛛的ＮＴＤ为最,斑络新妇幼体为次。蜘蛛－昆虫群落的营养结构在各样地上是一致的。蜘蛛作为捕食者,占总数１２－１５％。     

珍珠菜属系统发育关系的初步研究

本文运用形态学性状对珍珠菜属（Lysimachia)进行系统发育分析。内类群包括珍珠菜属29个代表种以及珍珠菜族其它单种、寡种属;仙客来属（Cylclamen)被选作外类群。最简约性分析表明,珍珠菜属并不构成－自然分类群;在其严格一致化树的二岐分支中,异花珍珠菜（L.crispidens)单独构成一支,其它所有内类群构成一支。香草亚属（subgen.Idiophyton)、木黄连花亚属（subgne.Lysimachiopsis)以及珍珠菜亚属（subgen.palladia)均表现为单系群,而黄连花亚属（subgen.Lysimachia)则为一异形的并系群。球尾花亚属（subgen.Naumburgia)仍“内藏”于珍珠菜属的主体之中。而喉鳞花亚属（subgen.Seleucia)则偏离出来而与七瓣莲属（Trien talis)构成姐妹群。如何准确地界定珍珠菜属和进行属下分类群的划分,还需进一步研究。     

Fast evolutionary genetic differentiation during experimental colonizations

Founder effects during colonization of a novel environment are expected to change the genetic composition of populations, leading to differentiation between the colonizer population and its source population. Another expected outcome is differentiation among populations derived from repeated independent colonizations starting from the same source. We have previously detected significant founder effects affecting rate of laboratory adaptation among Drosophila subobscura laboratory populations derived from the wild. We also showed that during the first generations in the laboratory, considerable genetic differentiation occurs between foundations. The present study deepens that analysis, taking into account the natural sampling hierarchy of six foundations, derived from different locations, different years and from two samples in one of the years. We show that striking stochastic effects occur in the first two generations of laboratory culture, effects that produce immediate differentiation between foundations, independent of the source of origin and despite similarity among all founders. This divergence is probably due to powerful genetic sampling effects during the first few generations of culture in the novel laboratory environment, as a result of a significant drop in N _e. Changes in demography as well as high variance in reproductive success in the novel environment may contribute to the low values of N _e. This study shows that estimates of genetic differentiation between natural populations may be accurate when based on the initial samples collected in the wild, though considerable genetic differentiation may occur in the very first generations of evolution in a new, confined environment. Rapid and significant evolutionary changes can thus occur during the early generations of a founding event, both in the wild and under domestication, effects of interest for both scientific and conservation purposes.     

Transport of electrons from mitochondria to microsomes in the reconstituted system of cell organelles

The reduction of cytochrome P-450--CO complex in the presence of various agents in the reconstituted system of liver cell organelles was studied. The reconstituted system was obtained by the preincubation of isolated liver microsomes and mitochondria of the rats kept on a prolonged phenobarbital diet. The addition of glutamate (but not succinate), NAD+ and amytal (or rotenone) to the reconstituted system caused a 40-50% reduction of NADPH-reducible cytochrome P-450. The inhibitor of mitochondrial NADH-cytochrome b5 reductase dicumarol prevented the cytochrome P-450 reduction in the presence of glutamate, NAD+ and amytal but did not affect the reduction of cytochrome P-450 by the added NADH. It was concluded that the electron transfer from the NAD-dependent substrates of the inner mitochondrial respiratory chain to the microsomal cytochrome P-450 occurs with the participation of non-bound NAD and cytochrome b5 of the outer mitochondrial membrane on the condition that the membranes of the two main oxidative systems are in tight contact.