Ca is involved in phytochrome A-dependent regulation of the succinate dehydrogenase gene sdh1-2 in Arabidopsis

The mechanism of transduction of the phytochrome signal regulating the expression of succinate dehydrogenase in Arabidopsis has been investigated. Using the phytochrome mutants of Arabidopsis, it is demonstrated that the inhibition of succinate dehydrogenase in the light may result from the phytochrome A-dependent modulation of Ca²⁺ amount in the nuclear fraction of leaves. This leads to the activation of expression of the gene pif3 encoding the phytochrome-interacting factor PIF3, which binds to the promoter of the gene sdh1-2 encoding the SDHA subunit of succinate dehydrogenase and suppresses its expression. It is concluded that Ca²⁺ ions are involved in the phytochrome A-mediated inhibition of succinate dehydrogenase activity in the light.     

The Role of Methylation of CpG Islands of the csy3 Gene Promotor in the Light Regulation of ATP-Citrate Lyase Activity in Maize Leaves

Russian Journal of Plant Physiology - It was established that the functioning of ATP-citrate lyase in maize (Zea mays L.) leaves is regulated by the light conditions of plants, in particular,...     

Role of transamination in the mobilization of respiratory substrates in germinating seeds of castor oil plants

The metabolism of 1,4-¹⁴C-succinate and 2,3-¹⁴C-succinate and the activity of succinic semialdehyde dehydrogenase (EC 1.2.1.16) were studied in germinating seeds of castor oil plants (Ricinus communis L.). Succinate metabolism involved succinate dehydrogenase and was sensitive to metabolites of the γ-aminobutyric acid shunt. Considerable accumulation of the label in amino acids reflected the progression of transamination reactions. Succinic semialdehyde dehydrogenase was purified from the endosperm of castor oil plants. Kinetic characteristics of the enzyme were evaluated. Our study indicates that the mobilization of respiratory substrates during germination of castor oil plants is related to active transamination of ketoacids in the Krebs cycle and involves the γ-aminobutyric acid shunt.     

Survival of civilian and prisoner drug-sensitive, multi- and extensive drug- resistant tuberculosis cohorts prospectively followed in Russia

Objective and Methods

A long-term observational study was conducted in Samara, Russia to assess the survival and risk factors for death of a cohort of non-multidrug resistant tuberculosis (non-MDRTB) and multidrug resistant tuberculosis (MDRTB) civilian and prison patients and a civilian extensive drug-resistant tuberculosis (XDRTB) cohort.

Results

MDRTB and XDRTB rates of 54.8% and 11.1% were identified in the region. Half (50%) of MDRTB patients and the majority of non-MDRTB patients (71%) were still alive at 5 years. Over half (58%) of the patients died within two years of establishing a diagnosis of XDRTB. In the multivariate analysis, retreatment (HR = 1.61, 95%CI 1.04, 2.49) and MDRTB (HR = 1.67, 95%CI 1.17, 2.39) were significantly associated with death within the non-MDR/MDRTB cohort. The effect of age on survival was relatively small (HR = 1.01, 95%CI 1.00, 1.02). No specific factor affected survival of XDRTB patients although median survival time for HIV-infected versus HIV-negative patients from this group was shorter (185 versus 496 days). The majority of MDRTB and XDRTB strains (84% and 92% respectively) strains belonged to the Beijing family. Mutations in the rpoB (codon 531 in 81/92; 88.8%), katG (mutation S315T in 91/92, 98.9%) and inhA genes accounted for most rifampin and isoniazid resistance respectively, mutations in the QRDR region of gyrA for most fluroquinolone resistance (68/92; 73.5%).

Conclusions

Alarmingly high rates of XDRTB exist. Previous TB treatment cycles and MDR were significant risk factors for mortality. XDRTB patients'' survival is short especially for HIV-infected patients. Beijing family strains comprise the majority of drug-resistant strains.     

Patterns of DNA Barcode Variation in Canadian Marine Molluscs

Background

Molluscs are the most diverse marine phylum and this high diversity has resulted in considerable taxonomic problems. Because the number of species in Canadian oceans remains uncertain, there is a need to incorporate molecular methods into species identifications. A 648 base pair segment of the cytochrome c oxidase subunit I gene has proven useful for the identification and discovery of species in many animal lineages. While the utility of DNA barcoding in molluscs has been demonstrated in other studies, this is the first effort to construct a DNA barcode registry for marine molluscs across such a large geographic area.

Methodology/Principal Findings

This study examines patterns of DNA barcode variation in 227 species of Canadian marine molluscs. Intraspecific sequence divergences ranged from 0–26.4% and a barcode gap existed for most taxa. Eleven cases of relatively deep (>2%) intraspecific divergence were detected, suggesting the possible presence of overlooked species. Structural variation was detected in COI with indels found in 37 species, mostly bivalves. Some indels were present in divergent lineages, primarily in the region of the first external loop, suggesting certain areas are hotspots for change. Lastly, mean GC content varied substantially among orders (24.5%–46.5%), and showed a significant positive correlation with nearest neighbour distances.

Conclusions/Significance

DNA barcoding is an effective tool for the identification of Canadian marine molluscs and for revealing possible cases of overlooked species. Some species with deep intraspecific divergence showed a biogeographic partition between lineages on the Atlantic, Arctic and Pacific coasts, suggesting the role of Pleistocene glaciations in the subdivision of their populations. Indels were prevalent in the barcode region of the COI gene in bivalves and gastropods. This study highlights the efficacy of DNA barcoding for providing insights into sequence variation across a broad taxonomic group on a large geographic scale.     

Expression of miRNAs in ovine fetal gonads: potential role in gonadal differentiation

Background  

Gonadal differentiation in the mammalian fetus involves a complex dose-dependent genetic network. Initiation and progression of fetal ovarian and testicular pathways are accompanied by dynamic expression patterns of thousands of genes. We postulate these expression patterns are regulated by small non-coding RNAs called microRNAs (miRNAs). The aim of this study was to identify the expression of miRNAs in mammalian fetal gonads using sheep as a model.     

Molecular evolution of mitochondrial 12S RNA and cytochrome b sequences in the pantherine lineage of Felidae

DNA sequence comparisons of two mitochondrial DNA genes were used to infer phylogenetic relationships among 17 Felidae species, notably 15 in the previously described pantherine lineage. The polymerase chain reaction (PCR) was used to generate sequences of 358 base pairs of the mitochondrial 12S RNA gene and 289 base pairs of the cytochrome b protein coding gene. DNA sequences were compared within and between 17 felid and five nonfelid carnivore species. Evolutionary trees were constructed using phenetic, cladistic, and maximum likelihood algorithms. The combined results suggested several phylogenetic relationships including (1) the recognition of a recently evolved monophyletic genus Panthera consisting of Panthera leo, P. pardus, P. onca, P. uncia, P. tigris, and Neofelis nebulosa; (2) the recent common ancestry of Acinonyx jubatus, the African cheetah, and Puma concolor, the American puma; and (3) two golden cat species, Profelis temmincki and Profelis aurata, are not sister species, and the latter is strongly associated with Caracal caracal. These data add to the growing database of vertebrate mtDNA sequences and, given the relatively recent divergence among the felids represented here (1-10 Myr), allow 12S and cytochrome b sequence evolution to be addressed over a time scale different from those addressed in most work on vertebrate mtDNA.