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Regulatory cystathionine β-synthase (CBS) domains are widespread in proteins; however, difficulty in structure determination prevents a comprehensive understanding of the underlying regulation mechanism. Tetrameric microbial inorganic pyrophosphatase containing such domains (CBS-PPase) is allosterically inhibited by AMP and ADP and activated by ATP and cell alarmones diadenosine polyphosphates. Each CBS-PPase subunit contains a pair of CBS domains but binds cooperatively to only one molecule of the mono-adenosine derivatives. We used site-directed mutagenesis of Desulfitobacterium hafniense CBS-PPase to identify the key elements determining the direction of the effect (activation or inhibition) and the "half-of-the-sites" ligand binding stoichiometry. Seven amino acid residues were selected in the CBS1 domain, based on the available X-ray structure of the regulatory domains, and substituted by alanine and other residues. The interaction of 11 CBS-PPase variants with the regulating ligands was characterized by activity measurements and isothermal titration calorimetry. Lys100 replacement reversed the effect of ADP from inhibition to activation, whereas Lys95 and Gly118 replacements made ADP an activator at low concentrations but an inhibitor at high concentrations. Replacement of these residues for alanine increased the stoichiometry of mono-adenosine phosphate binding by twofold. These findings identified several key protein residues and suggested a "two non-interacting pairs of interacting regulatory sites" concept in CBS-PPase regulation.

An efficient cascade approach to thiosubstituted benzoxazoles has been developed. The transformation starts with in situ generation of a diazo compound via annulation-triggered electrocyclic opening of the 1,2,3-triazole ring. The subsequent Cu-catalyzed trapping of diazo intermediates by various thiols affords the desired heterocycles in generally good yields of up to 91%. The protocol features very good functional group tolerance and is applicable to substrates with different electronic properties.

Fry of five species of salmonids are found in the lower reaches of the Ozernaya River. The most abundant are chum salmon and pink salmon which compose the bulk of fry which migrate downstream from the river to the sea. The dates and duration of migration of particular species differed according to the specific traits of their biology. Pink salmon is characterized by a simple migration strategy: it migrated downstream in a short time after emergence from theground. Chum salmon has two strategies of downstream migration: some fry start migration soon after emergence, and others remained in the river for several weeks. Downstream migration of pink salmon occurred mainly at night in contrast to that of chum salmon, over 24 h, the part of daytime increased with growth, of the fish. Migration of pink salmon was passive. Passive migration of chum salmon changed into active-passive with growth of the fish. The ratio of fish in the inshore zone and in the current was different in the course of 24 h. The number of fish in the inshore zone decreased in the period of intensive downstream migration.

The principal characteristics of feeding of downstream-migrant and coastal young of the year of coho salmon are considered. The so-called potential downstream migrants and residents, which differ in size and feeding patterns, were distinguished among coastal fry. It is assumed that identification of particular coastal specimens to phenotypic groups of downstream migrants or nonmigrants of young of the year ofcoho salmon may be determined even in the daytime by such parameters as the body length, feeding intensity, and food spectrum.

We report on a case of chimerism and multiple abnormalities of chromosomes 21, Xand Yin spontaneous abortion specimen. To the best our knowledge the present case is the first documented chimera in a spontaneously aborted fetus. The application of interphase fluorescence in situ hybridization (FISH) using chromosome enumeration and site-specific DNA probes showed trisomy X in 92 nuclei (23 %), tetrasomy X in 100 nuclei (25 %), pentasomy of chromosome X in 40 nuclei (10 %), XXY in 36 nuclei (9 %), XXXXXXYY in 12 nuclei (3 %), XXXXXYYYYY in 8 nuclei (2 %), trisomy 21 and female chromosome complement in 40 nuclei (10 %), normal female chromosome complement in 72 nuclei (18 %) out of 400 nuclei scored. Our experience indicates that the frequency of chimerism coupled with multiple chromosome abnormalities should be no less than 1 : 400 among spontaneous abortions. The difficulties of chimerism identification in fetal tissues are discussed.

According to different estimates, as high as 15-20% of all the pregnancies result in spontaneous abortions (SA) at different gestational periods. Identification of abnormalities leading to SA is of great importance for practical medicine, mainly for medical genetic counseling of married couples with impaired reproductive function. The diagnosis of chromosomal aberrations on the basis of SA materials is known to have a number of methodological difficulties. The present paper deals with the identification of numerical anomalies in the SA material by multicolor fluorescence in situ hybridization (MFISH). This technique using an original collection of DNA probes for chromosomes 1, 9, 13/21, 14/22, 15, 16, 18, X, and Y was applied to the study of chromosomal aberrations in 224 spontaneous abortion specimens. Numerical chromosomal aberrations were found in 122 (54.5%) cases. The cells of all the studied specimens exhibited aneuploidy of chromosome X in 17% cases; chromosome 16 in 12%, chromosomes 13/21 in 5.8%, chromosomes 14/22 in 4.9%, chromosomes 9 and 18 in 1.3% (each), chromosome 15 in 0.9%, chromosome 1 in 0.45%. Polyploidy was detected in 13.3% of cases; concomitant abnormalities were found in 7 cases. Analysis of the findings has led to the conclusion that MFISH can be successfully used in the diagnosis of numerical chromosomal aberrations of CA cells.

Numerical chromosomal imbalances are a common feature of spontaneous abortions. However, the incidence of mosaic forms of chromosomal abnormalities has not been evaluated. We have applied interphase multicolor fluorescence in situ hybridization using original DNA probes for chromosomes 1, 9, 13, 14, 15, 16, 18, 21, 22, X, and Y to study chromosomal abnormalities in 148 specimens of spontaneous abortions. We have detected chromosomal abnormalities in 89/148 (60.1%) of specimens. Among them, aneuploidy was detected in 74 samples (83.1%). In the remaining samples, polyploidy was detected. The mosaic forms of chromosome abnormality, including autosomal and sex chromosomal aneuploidies and polyploidy (31 and 12 cases, respectively), were observed in 43/89 (48.3%) of specimens. The most frequent mosaic form of aneuploidy was related to chromosome X (19 cases). The frequency of mosaic forms of chromosomal abnormalities in samples with male chromosomal complement was 50% (16/32 chromosomally abnormal), and in samples with female chromosomal complement, it was 47.4% (27/57 chromosomally abnormal). The present study demonstrates that the postzygotic or mitotic errors leading to chromosomal mosaicism in spontaneous abortions are more frequent than previously suspected. Chromosomal mosaicism may contribute significantly to both pregnancy complications and spontaneous fetal loss.

Morphological investigation of spontaneous abortions (SA) with normal and abnormal karyotype (220 specimens of the first trimester SA) was carried out. It included a histological pattern, apoptosis and proliferative activity. Estimation of apoptotic index (AI) was carried out in 7 cases of SA with normal karyotype and 7 cases of SA with pathological karyotype using the ApopTag Peroxidase Kits (Biotech, USA). The material of 4 therapeutic abortions was taken as the control group. The proliferative activity (PA) was determined as the rate of Ki-67-positive cytotrophoblast cells. PA was examined in SA groups with normal (15 cases) and pathological (15 cases) karyotypes and 20 cases of control group. Identical morphological signs of the development retardation of the villi were diagnosed among abortuses with normal karyotype and with aneuploidies. The diameter of the villi was bigger in aneuploid SA than in SA with normal karyotype (p > 0.05). The partial moles were diagnosed in triploidy, as it was expected. High level of AI and PA in the control group was revealed. In SA with pathological karyotype a high rate of AI accompanied a low level of PA. The AI and PA were low in SA with normal karyotype. However, the largest uncorrelation between AI and PA in extravillous trophoblast cells of SA with chromosomal anomalies were observed: the level of AI was higher than the level of PA. We suppose that the last one leads to the abruption of the ovum.

Frequencies of extreme C segments of chromosomes 1, 9, and 16 were studied in patients with isolated gonadotropin deficiency (I), gonadotropin resistant ovary (I), and polycystic ovarian disease (III). Increased chromosome 9 heterochromatin was revealed for all syndromes, and increased chromosome 1 heterochromatin was revealed for groups II and III. Identical changes in heterochromatic parts of chromosomes, linked with increased heterochromatin, probably suggest a lack of specificity for the syndromes studied.

Clinical-genetic examination of 50 patients with menopause praecox syndrome has been performed. The results of the examination show genetic syndrome heterogeneity. Chromosomal and gene mutations take part in the syndrome pathogenesis. Chromosomal abnormalities frequency is 12%. Chromosomal aberrations are presented by different mosaicism types of sex chromosomes. Monogenic syndrome genesis with different inheritance types of the pathologic gene is determined: autosomal-recessive or autosomal-dominant.

A comparative study has been made of glycosaminoglycan (GAG) accumulation in human fibroblasts with trisomy 7 and triploidy from spontaneous abortuses, fibroblasts with triploidy from induced abortuses, fibroblasts from patients with Down's syndrome and diploid fibroblasts from age-matched controls. The study demonstrated that the incorporation of [3H] glucosamine into hyaluronic acid by fibroblasts with trisomy 7 and triploidy, established from spontaneous abortuses, and from two out of three induced abortuses with triploidy, was 2.6-5.3 times lower than control incorporation. One strain of fibroblasts from an induced abortus with triploidy (IMG-1062) did not show any differences in GAG production when compared with diploid fibroblasts. However, the strains from children with Down's syndrome revealed normal or even increased levels of hyaluronic acid production. The data support the contention that the decreased hyaluronic acid synthesis in fibroblasts with an abnormal karyotype is related to spontaneous abortion.

In search of the basis of distinguishing amenorrhea, due to chromosomal mosaicism and other causes, 179 females affected by primary or secondary amenorrhea were examined, 83 of them being 45,X/46,XX mosaics. 119 traits characterizing the morphological status of the musculoskeletal and reproductive systems, as well as skin, hair and nails were scored. By means of statistical approaches, a group of 21 traits were specified, which makes it possible to diagnose the amenorrhea of chromosomal origin. Statistically significant association between the clinical manifestations and the rate of mosaicism was shown.

35 patients with unclassified urogenital malformations were subjected to clinical and cytogenetic examination. Chromosome aberrations of the mosaicism type were found in 3 women. They were as follows: 45,X/46,XX(2); 45, X/46, XX/47, XXX(1). Moreover, two patients had identical pericentric inversions of chromosome 9: 46, XX, inv. (9) (p13; q13) and 3 patients had microvariants of acrocentric chromosomes. Despite the presence of chromosome anomalies and morphological variants of chromosomes in the examined patients, the comparison of the clinical and cytogenetic data suggests the multifactorial nature of urogenital malformation.