Prevalence of type III secretion system genes in cholera vibrios from different serogroups

Prevalence of vcs genes coding the type III secretion system (T3SS) in cholera vibrios of different serogroups isolated in Russia and neighboring countries was studied for the first time. Virulent strains of O1 and O139 serogroups as well as toxigenic Vibrio cholerae strains of other serogroups contained no T3SS genes. Unlike mentioned strains, 29.2% of atoxigenic non O1/non O139 cholera vibrios isolated from patients in Russia and neighboring countries contained the T3SS genes cluster, which might contribute to the pathogenic properties of these strains.     

Genetic heterogeneity of Borrelia afzelii in the natural focus of the Middle Urals

As shown by sequencing the spacer rrf (5S)--rrl (23S) in 72 isolates of B. afzelii (one of the causative agents of Ixodes tick borne Borrelia infections) and the chromosomal gene coding protein P66 in 22 isolates, that in the natural focus located in the Middle Urals two different genetic subgroups (VS461 and NT28) of this genospecies simultaneously circulate. These subgroups are represented by 5 gene variants (rrf) 5S--(rrl) 23S and 5 allelic variants in gene p66. The latter, similarly to spacer gene variants, are not linked with a definite host and occur in different rrf--rrl variants of the infective agent. At the same time the definite species of vectors and carriers may be the host of several different B. afzelii variants, both in the spacer and in the gene coding protein P66, which maintains the genetic heterogeneity of B. afzelii population in the natural focus.     

Development of a PCR-based method for diagnostics of mycoses

Since the express-diagnostics of mycoses in immune-deficit patients still remains an acute problem, we developed an effective test system (Kan-Am) to detect DNA Candida albicans, which is a leader in the list of causative agents of candidosis. A comparison study of three PCR-systems used to detect a broad spectrum of fungoid pathogens was carried out, and a universal system (FungAm), which ensures the detection of DNAs of above 78 strains of 25 types of pathogenic fungi, was selected. The results of clinical testing of the species-specific and universal PCR-systems are well confirmed by the culture method, and they are indicative of the efficacy of applying them for the diagnostics of mycoses in neonatology. The use of the mentioned systems is a promising factor for the express-diagnostics of mycoses in immunodeficiency patients. The high sensitivity of the method makes it possible to detect 10 to 100 cells of a causative agent in 100 mcl of the examined biological material, which is compatible with the culture method. A kit of dry reagents (IonoMix) designed for an accelerated sample preparation and isolation, from them, of DNAs on the basis of Chelex-100 and of proteinase K was worked out; the kit is portable and meant for a long-term storing.     

Insertion of transposon P(lacW) with gradual expression of reporter genes

In Drosophila, insertions of the P?lacW? transposon led to uncommon expression patterns of the reporter genes white and lacZ: gene activity was gradually reduced in the neighboring cells along the dorsal-ventral or proximal-distal axes. Using in situ hybridization, the gradual gene expression was shown to be caused by P?lacW? insertions in regions 40A (lines G1 and G2) and 69C (line G3) of the Drosophila genome. The expression patterns of genes lacZ and white were similar in eye cells of each line. In salivary gland polytene cells of G3 flies, the lacZ expression was also gradually reduced, which indicates the existence of a mechanism maintaining the gene activity gradient during endomitosis.     

A Finding of the Red Squirrel (Rodentia,Sciuridae, <Emphasis Type="Italic">Sciurus vulgaris</Emphasis> Linnaeus, 1758) and Forest Dormouse (Rodentia,Gliridae, <Emphasis Type="Italic">Dryomys nitedula</Emphasis> Linnaeus, 1778) in the Pleistocene of the Southern Urals

The study deals with a new sample of the mammalian fossils from the Pleistocene deposits of the Ignatievskaya Cave in Southern Urals (54°53' N, 57°46' E). Among the rodent fossils, the teeth of red squirrel (Sciurus vulgaris) and forest dormouse (Dryomys nitedula) have been identified. The enamel differentiation quotient (SDQ) of the water vole teeth matches the Arvicola terrestris species from locations of the end of Middle and Late Pleistocene (oxygen isotope stages, OIS 6 and OIS 5–2, respectively). The high SDQ value for the water vole and the presence of the squirrel and dormouse in the fauna allow dating the finding near the end of the Middle Pleistocene and beginning of the Late Pleistocene (OIS 6 and OIS 5e, respectively). The widespread open and forest landscapes were inhabited by this fauna.     

Structural basis for polyspecificity in the POT family of proton‐coupled oligopeptide transporters

An enigma in the field of peptide transport is the structural basis for ligand promiscuity, as exemplified by PepT1, the mammalian plasma membrane peptide transporter. Here, we present crystal structures of di‐ and tripeptide‐bound complexes of a bacterial homologue of PepT1, which reveal at least two mechanisms for peptide recognition that operate within a single, centrally located binding site. The dipeptide was orientated laterally in the binding site, whereas the tripeptide revealed an alternative vertical binding mode. The co‐crystal structures combined with functional studies reveal that biochemically distinct peptide‐binding sites likely operate within the POT/PTR family of proton‐coupled symporters and suggest that transport promiscuity has arisen in part through the ability of the binding site to accommodate peptides in multiple orientations for transport.     

可切除的食管胃结合部腺癌的联合治疗

近年来胃癌的发病率有所下降,相比之下胃食管结合部腺癌的发病率却快速增长。手术治疗仍然是早期食管胃结合部腺癌的标准治疗方法,同时手术联合化疗、放化疗治疗食管胃结合部腺癌也逐渐得到国际认可。尽管在手术治疗、放疗和化疗治疗技术得到完善和改进,但食管癌和食管胃结合部腺癌的预后仍然较差。目前有数个大型临床随机对照试验数据支持对食管下端和食管胃交界部腺癌使用术前联合化疗,但辅助治疗的贡献仍不能确定。最近有meta分析表明手术联合化疗、放化疗可以提高胃食管结合部腺癌患者术后存活率,但也有一些临床随机试验的数据表明手术联合化疗、放化疗并无明显好处。本文通过总结最新的临床试验及meta分析结果,阐述不同的可切除的胃食管结合部腺癌的联合治疗方法。     

Comparison of dot chromosome sequences from D. melanogaster and D. virilis reveals an enrichment of DNA transposon sequences in heterochromatic domains

Background

Chromosome four of Drosophila melanogaster, known as the dot chromosome, is largely heterochromatic, as shown by immunofluorescent staining with antibodies to heterochromatin protein 1 (HP1) and histone H3K9me. In contrast, the absence of HP1 and H3K9me from the dot chromosome in D. virilis suggests that this region is euchromatic. D. virilis diverged from D. melanogaster 40 to 60 million years ago.

Results

Here we describe finished sequencing and analysis of 11 fosmids hybridizing to the dot chromosome of D. virilis (372,650 base-pairs) and seven fosmids from major euchromatic chromosome arms (273,110 base-pairs). Most genes from the dot chromosome of D. melanogaster remain on the dot chromosome in D. virilis, but many inversions have occurred. The dot chromosomes of both species are similar to the major chromosome arms in gene density and coding density, but the dot chromosome genes of both species have larger introns. The D. virilis dot chromosome fosmids have a high repeat density (22.8%), similar to homologous regions of D. melanogaster (26.5%). There are, however, major differences in the representation of repetitive elements. Remnants of DNA transposons make up only 6.3% of the D. virilis dot chromosome fosmids, but 18.4% of the homologous regions from D. melanogaster; DINE-1 and 1360 elements are particularly enriched in D. melanogaster. Euchromatic domains on the major chromosomes in both species have very few DNA transposons (less than 0.4 %).

Conclusion

Combining these results with recent findings about RNAi, we suggest that specific repetitive elements, as well as density, play a role in determining higher-order chromatin packaging.     

Biologically relevant effects of mRNA amplification on gene expression profiles

Background  

Gene expression microarray technology permits the analysis of global gene expression profiles. The amount of sample needed limits the use of small excision biopsies and/or needle biopsies from human or animal tissues. Linear amplification techniques have been developed to increase the amount of sample derived cDNA. These amplified samples can be hybridised on microarrays. However, little information is available whether microarrays based on amplified and unamplified material yield comparable results.