产β—葡萄糖苷酶真菌诱变菌株快速筛选方法

报道了一种快速筛选产β-葡萄糖管酶真菌诱变菌株的方法。该法利用ρNPG经β-葡萄糖苷酶水解,水解产物ρNP在碱性条件下显色的原理。采用自制的特殊初筛平皿.经一年多的实践应用表明此法具有简便、灵敏、筛子消耗量小、筛选效率高等优点。     

Genetic evidence of extensive introgression of short-tailed ground squirrel genes in a hybridization zone of Spermophilus major and S. erythrogenys, inferred from sequencing of the mtDNA cytochrome b gene

We have completely sequenced the mtDNA cytochrome b gene of ground squirrels from the zone of overlapping ranges of Spermophilus major and S. erythrogenys in the Tobol-Ishim interfluve, which is a putative hybridization zone of these species. The results of the sequencing showed extensive introgression of mtDNA genes of the short-tailed ground squirrel S. e. brevicauda, whose haplotype had fully replaced the S. major haplotype. All of the ground squirrels from the Tobol-Ishim interfluve had a variant of the S. e. brevicauda mtDNA haplotype that was specific for this zone. On average, 119 substitutions (10.44%) were found between S. major from Ul'yanovsk oblast and S. e. brevicauda from the northern Kazakhstan, the mean genetic distance (D) between them being 0.115, which conforms to the corresponding parameters for the S. e. brevicauda-S. pygmaeus pair (122 substitutions, D = 118). Insignificant differences (seven substitutions, D = 0.043) were found between the S. major and S. pygmaeus haplotypes, which suggest that these species have similar mitochondrial haplotypes. Five to ten nucleotide substitutions (0.44--0.88%) were detected between the animals from the Tobol--Ishim interfluve and S. e. brevicauda. The mtDNA haplotype divergence D within the genus Spermophilus (ten species) for all codon positions ranged from 0.035 to 0.158. Phylogenetic reconstructions (MP, ML, and NJ trees) showed two well-differentiated clusters with high bootstrap support. However, there was different branching topology within the cluster and their species composition varied. The maximum likelihood tree, ML, differentiating the species into two subgenera, Citellus and Colobotis, most reliably reflected taxonomic relationships of the species from the genus Spermophilus, inferred from morphological and genetic biochemical data. The morphologically pure S. major (subgenus Colobotis) animals, used in the analysis, proved to carry the haplotype of another species, S. pygmaeus (subgenus Citellus). This poses a question on the existence of the specific haplotype of S. major, the reason of its replacement by haplotype of other species, and possible consequences of this phenomenon for survival of the species.     

Role of HLA DRB1*15 and HLA DRB1*16alleles in the genetic susceptibility to develop systemic lupus erythematosus (SLE) after Chikungunya and Zika viruses infection in México

Systemic lupus erythematosus (SLE) is a clinically and genetically heterogeneous disease particularly prevalent in Mexico. Althoughits etiology is unknown, genetic factors strongly influence its presenceas well as triggering factors, such as viral infections, including Cytomegalovirus and Epstein-Barr virus. Here,the study presents the appearance of de novoSLE (patients who did not present SLE before de virus infection, corroborated by serological analysis and negative for antinuclear antibodies) cases in Mexicans who live near the southern border of Mexico, who presented clinical symptoms of arthritic, hematological, mucocutaneous and renal SLE, after Zika and/ or Chikungunya virus infection. Low resolution class Ⅱ HLA typing was performed, which found a significantly increased frequency of HLA DRB1*02 (15 and 16)when compared to a group of 99 healthy individuals (P =0.001, OR=4.5, IC95% 1.8~11.0). All the patients were diagnosed with SLE 1 to 3 years after being confirmed with the Zika, and/or Chikungunya infection. At the point of acute viral infection, none of the patients presented clinical signs or symptoms of autoimmunity or were negative for antinuclear antibodies. In genetically susceptible individuals, Zika and Chikungunya viral infection can trigger SLE.     

Identification of sterol-containing domains in vacuolar membranes by confocal microscopy

Sterol-containing domains in the tonoplast of beet root cells were identified by confocal microscopy with a membrane probe filipin. The presence of sterol-containing domains in the tonoplast was confirmed using methyl-β-cyclodextrin. Sterol-containing domains with separate small intensely fluorescing sterol-enriched sites were found in the vacuolar membrane; these sites can be attributed to raft structures. It was shown that sterol content in the isolated rafts can be assessed by confocal microscopy. β-Sitosterol, stigmasterol, α-tocopherol, and cholesterol were identified among the sterols of the isolated rafts.     

The four hexamerin genes in the honey bee: structure,molecular evolution and function deduced from expression patterns in queens,workers and drones

Background  

Hexamerins are hemocyanin-derived proteins that have lost the ability to bind copper ions and transport oxygen; instead, they became storage proteins. The current study aimed to broaden our knowledge on the hexamerin genes found in the honey bee genome by exploring their structural characteristics, expression profiles, evolution, and functions in the life cycle of workers, drones and queens.     

Metabolic versatility of haloalkaliphilic bacteria from soda lakes belonging to the Alkalispirillum–Alkalilimnicola group

Four new isolates were obtained from denitrifying enrichments with various electron donors using sediment samples from hypersaline soda lakes. Based on 16S rRNA gene analysis and DNA-DNA hybridization results, they were all identified as members of the Gammaproteobacteria closely associated with the Alkalispirillum–Alkalilimnicola group. Two isolates were obtained from samples enriched with nitrate as electron acceptor and H₂ or polysulfide as electron donors, and another two strains were obtained with N₂O as the electron acceptor and sulfide or acetate as electron donors. All four new isolates, together with the type strains of the genera Alkalispirillum and Alkalilimnicola originally described as obligate aerobes, were capable of anaerobic growth with acetate using either nitrate or N₂O as electron acceptors. Their denitrification pathway, however, was disrupted at the level of nitrite. RuBisCO form I gene was detected and sequenced in the new isolates and in Alkalilimnicola halodurans but not in Alkalispirillum mobile. These data, together with the evidence of Oremland et al. (Appl Environ Microbiol 68:4795–4802, 2002) on the potential of Alkalilimnicola sp. MLHE-1 for autotrophic growth with arsenite as electron donor and nitrate as electron acceptor, demonstrate much higher metabolic diversity of this specific group of haloalkaliphilic Gammaproteobacteria than was originally anticipated.     

An Oligonucleotide Primer System for Amplification of the Ribulose-1,5-Bisphosphate Carboxylase/Oxygenase Genes of Bacteria of Various Taxonomic Groups

Based on the analysis of GenBank nucleotide sequences of the cbbL and cbbM genes, coding for the large subunit of ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBPC), the key enzyme of the Calvin cycle, a primer system was designed that allows fragments of these genes about 800 bp long to be PCR-amplified for various photo- and chemotrophic bacteria. The efficiency of the designed primer system in detection of RuBPC genes was demonstrated in PCR with DNA of taxonomically diverse bacteria possessing RuBPC genes with a known primary structure. Nucleotide sequences of RuBPC gene fragments of bacteria belonging to the genera Acidithiobacillus, Ectothiorhodospira, Magnetospirillum, Methylocapsa, Thioalkalispira, Rhodobacter, and Rhodospirillum were determined to be deposited with GenBank and to be translated into amino acid sequences and subjected to phylogenetic analysis.     

The dose estimation to the population as a result of radioactive contamination of the Semipalatinsk Test area

The results are presented from estimation of spatial distribution of 137Cs and 90Sr contamination densities in the areas of horses and sheep grazing within the Semipalatinsk Test Site. Dose burdens to various cohorts of the population living within the STS and consuming contaminated animal products are predicted. Doses of shepherds in the most contaminated pasture areas have been found to exceed the accepted limit (1 mSv/y). The conclusion is made about the need for further studies on the risk assessment of the STS population exposure above the accepted limits.     

The origin of Yakuts: analysis of Y-chromosome haplotypes

Gene pool structure of Sakha Republic (Yakutia) native population has been studied: we defined composition and frequencies of Y-chromosome haplogroups for Yakuts. Six haplogroups: C3 x M77, C3c, N*, N2, N3a and R1a1 have been revealed in Yakut gene pool. A greater part of Y-chromosome in Yakut population belongs to N3a haplogroup (89%). All investigated Yakut population samples have low values of gene diversity, calculated based on haplogroup frequencies. Gene differentiation of the investigated samples estimated using the analysis of molecular variance (AMOVA) by two marker systems (haplogroup frequencies and microsatellite haplotypes of Y-chromosome) revealed a portion of interpopulation differences amounting to 0.24 and 2.85%, respectively. Frequencies and molecular phylogeny of YSTR-haplotypes were revealed for N3a haplogroup of Y-chromosome. Altogether forty haplotypes were found in Yakuts. Evenks and Yakuts are characterized by overlapping and very specific spectrum of N3a haplotypes, which is not typical for other Siberian ethnic groups. Cluster analysis of populations by N3a YSTR-haplotypes shows Yakut isolation from Turkic-speaking populations in the South Siberia. Genetic diversity generation time for a specific spectrum of Yakut haplotypes was estimated as 4.45 +/- 1.96 thousand years. As opposed to the data on mtDNA, the obtained results give an evidence for significant contribution of a local palaeolithic component into Y-chromosomal Yakut gene pool. Ethnogenetic reconstruction of the present picture of genetic diversity in N3a haplogroup in the territory of Siberia is under consideration.