Diversity,migration routes,and worldwide population genetic structure of Lecanosticta acicola,the causal agent of brown spot needle blight

Lecanosticta acicola is a pine needle pathogen causing brown spot needle blight that results in premature needle shedding with considerable damage described in North America, Europe, and Asia. Microsatellite and mating type markers were used to study the population genetics, migration history, and reproduction mode of the pathogen, based on a collection of 650 isolates from 27 countries and 26 hosts across the range of L. acicola. The presence of L. acicola in Georgia was confirmed in this study. Migration analyses indicate there have been several introduction events from North America into Europe. However, some of the source populations still appear to remain unknown. The populations in Croatia and western Asia appear to originate from genetically similar populations in North America. Intercontinental movement of the pathogen was reflected in an identical haplotype occurring on two continents, in North America (Canada) and Europe (Germany). Several shared haplotypes between European populations further suggests more local pathogen movement between countries. Moreover, migration analyses indicate that the populations in northern Europe originate from more established populations in central Europe. Overall, the highest genetic diversity was observed in south‐eastern USA. In Europe, the highest diversity was observed in France, where the presence of both known pathogen lineages was recorded. Less than half of the observed populations contained mating types in equal proportions. Although there is evidence of some sexual reproduction taking place, the pathogen spreads predominantly asexually and through anthropogenic activity.     

Netropsin stimulates the formation of an extracellular proteinase and suppresses protein turnover in sporulating Bacillus megaterium

Abstract Netropsin stimulated the rate of synthesis of an extracellular metalloproteinase in Bacillus megaterium incubated in a sporulation medium. The antibiotic delayed but did not suppress the decrease in the ability to synthesize the proteinase occurring at later sporulation stages. Netropsin also stimulated the synthesis of the proteinase when added to a growing culture; it inhibited the increase of protein turnover which was switched on between the 2nd and 3rd hour in the sporulating population. No refractile spores were developed during 6 h at 35°C in the antibiotic-treated culture. In the control 60% of sporulating cells were observed under similar conditions.     

The mode of action of thidiazuron: auxins,indoleamines, and ion channels in the regeneration of <Emphasis Type="Italic">Echinacea purpurea</Emphasis> L.

The biochemical mechanisms underlying thidiazuron (TDZ)-induced regeneration in plant cells have not been clearly elucidated. Exposure of leaf explants of Echinacea purpurea to a medium containing TDZ results in undifferentiated cell proliferation and differentiated growth as mixed shoot organogenesis and somatic embryogenesis. The current studies were undertaken to determine the potential roles of auxin, indoleamines, and ion signaling in the dedifferentiation and redifferentiation of plant cells. E. purpurea leaf explants were found to contain auxin and the related indoleamine neurotransmitters, melatonin, and serotonin. The levels of these endogenous indoleamines were increased by exposure to TDZ associated with the induction of regeneration. The auxin-transport inhibitor 2,3,5-triiodobenzoic acid and auxin action inhibitor, p-chlorophenoxyisobutyric acid decreased the TDZ-induced regeneration but increased concentrations of endogenous serotonin and melatonin. As well, inhibitors of calcium and sodium transport significantly reduced TDZ-induced morphogenesis while increasing endogenous indoleamine content. These data indicate that TDZ-induced regeneration is the manifestation of a metabolic cascade that includes an initial signaling event, accumulation, and transport of endogenous plant signals such as auxin and melatonin, a system of secondary messengers, and a concurrent stress response.     

Adaptogenic functions of extracellular autoregulators of microorganisms

Information about the functions of extracellular autoregulators, which adapt microorganisms to the stresses “scheduled” in the development cycle of microbial cultures (stresses of new medium, starvation, or space exhaustion (high cell density)) is summarized in the review. In a number of bacteria and yeasts, derivatives of alkylhydroxybenzenes (AHB), particularly of the class of alkyl resorcinols, act as autoregulators with adaptogenic functions. The chemical structure of AHB determines their amphiphility; capacity for physical and chemical interaction with membrane lipids, proteins, and DNA; properties as natural modifiers of biological membranes and enzymes; and the expression of antioxidant activity. Increase of AHB concentration up to the critical level (10^?5-10^?4 M) results in cessation of cell division and in transition of the microbial culture to the stationary phase; further increase to 10^?4-10^?3 M induces a transition of some of the cells of a post-stationary culture to the anabiotic state with the formation of cystlike resting cells (CRC), even in non-spore-forming bacteria. AHB participate in the regulation of the phenotypic variability of bacteria. The dynamics of extra-and intracellular concentrations of AHB in growing microbial cultures and the polymodality of their effect determine the adaptogenic functions of AHB as autoinhibitors of culture growth, autoinducers of anabiosis, and autoinhibitors of germination of resting forms. Manifestation of any given function depends on the concentration of AHB, the physiological state of the recipient cells, and on environmental factors. The species nonspecificity of AHB effects points to their significant role in the regulation of the development and functioning of microbial communities.     

Genome-wide association study of bronchial asthma in the Volga-Urals region of Russia

Bronchial asthma is a chronic inflammatory respiratory disease caused by a complex interaction of environmental influences and genetic susceptibility. The first genome-wide association study of bronchial asthma discovered a significant association between single nucleotide polymorphisms (SNPs) located within the genomic region 17q12-q21 and childhood bronchial asthma in individuals of European descent. This result was later replicated in a number of independent population samples of European and Asian origin. Here we report the results of the first genome-wide association study of bronchial asthma in the Volga-Urals region of Russia. The study involved 358 unrelated patients with physician-diagnosed bronchial asthma and 369 disease-free control subjects of different ethnicity (Russians, Tatars, and Bashkirs). DNA specimens were genotyped using an Illumina Human610 quad array as a part of the GABRIEL project (EC contract no. LSHB-CT-2006-018996). After QC filtering procedures, a final set of 550 915 SNPs genotyped in 330 patients and 348 controls was tested for association with bronchial asthma. Five markers on chromosome 17q12-21 showed significant association with bronchial asthma (p ≤ 4.79 × 10⁻⁷). The rs7216389 SNP located in GSDMB intron 1 showed the strongest evidence for association (p = 1.01 × 10⁻⁷). Association with childhood asthma (p = 1.97 × 10⁻⁶ for rs7216389) was stronger than with late-onset asthma (p = 1.8 × 10⁻⁴ for rs7216389). A replication study of three SNPs located within GSDMB confirmed association only with childhood asthma. In sum, these results suggest that genetic variants of 17q12–q21 play an important role in susceptibility to bronchial asthma in the Volga-Urals region of Russia.     

Heliobacterium sulfidophilum sp. nov. andHeliobacterium undosum sp. nov.: Sulfideoxidizing heliobacteria from thermal sulfidic springs

Two new species of heliobacteria isolated from cyanobacterial mats of two alkaline sulfidic hot springs are formally described. Strains BR4 and BG29 are assigned to anoxygenic phototrophic bacteria of the familyHeliobacteriaceae, since they possess the unique properties of this taxon: strict anaerobiosis, formation of bacteriochlorophyllg, the lack of extensive intracytoplasmic membranes and chlorosomes, an unusual cell wall structure, and phylogenetic relatedness to the low G+C gram-positive eubacteria. Based on the 16S rDNA sequence similarity, strains BR4 and BG29 are assigned to the genusHeliobacterium and described as two new species of this genus:Heliobacterium sulfidophilum sp. nov. andHeliobacterium undosum sp. nov. The G+C content of the DNA is 51.3 mol % inHbt. sulfidophilum and 57.2-57.7 mol % inHbt. undosum. The cells ofHbt. sulfidophilum are rods, and the cells ofHbt. undosum are slightly twisted spirilla or short rods. Both new bacteria are motile by peritrichous flagella.Hbt. sulfidophilum produces endospores. The new bacteria are strict anaerobes growing photoheterotrophically on a limited range of organic compounds. In the dark, they can switch from photosynthesis to the slow fermentation of pyruvate. Biotin is required as a growth factor. Both species are highly tolerant to sulfide (up to 2 mM at pH 7.5) and oxidize it photoheterotrophically to elemental sulfur; photoautotrophic growth was not observed. The temperature optimal for growth ofHbt. sulfidophilum andHbt undosum is 30–35‡C, and the optimal pH is 7–8.     

Effect of vitamin concentration on the synthesis of lactate, ethanol, pyruvate, and ethyl acetate in cells of the yeast Dipodascus magnusii

In the yeast Dipodascus magnusii, which is auxotrophic for thiamine and biotin, during cultivation on glucose with excessive thiamine concentration, pyruvate metabolism was shown to result in the synthesis of fermentation products, namely, ethanol and, to a lesser extent, lactate. Substantial synthesis of ethyl acetate was also observed under these conditions. Introduction of nicotinic acid (NA) into the medium resulted in time separation of ethanol and lactate production. It was shown that cultivation of the yeast under biotin deficiency resulted in nearly complete suppression of aerobic production of ethanol and cessation of ethyl acetate synthesis, whereas lactate synthesis was activated as early as in the first hours of cultivation. Upon introduction of NA under these conditions, lactate concentration sharply increased. These results show that the combination of thiamine and biotin with other vitamins can stimulate utilization of the pyruvate pool in yeasts towards formation of considerable amounts of lactate, which is typical only of cells of higher eukaryotes and bacteria.     

Protein glycosylation pathways in filamentous fungi

Glycosylation of proteins is important for protein stability, secretion, and localization. In this study, we have investigated the glycan synthesis pathways of 12 filamentous fungi including those of medical/agricultural/industrial importance for which genomes have been recently sequenced. We have adopted a systems biology approach to combine the results from comparative genomics techniques with high confidence information on the enzymes and fungal glycan structures, reported in the literature. From this, we have developed a composite representation of the glycan synthesis pathways in filamentous fungi (both N- and O-linked). The N-glycosylation pathway in the cytoplasm and endoplasmic reticulum was found to be highly conserved evolutionarily across all the filamentous fungi considered in the study. In the final stages of N-glycan synthesis in the Golgi, filamentous fungi follow the high mannose pathway as in Saccharomyces cerevisiae, but the level of glycan mannosylation is reduced. Highly specialized N-glycan structures with galactofuranose residues, phosphodiesters, and other insufficiently trimmed structures have also been identified in the filamentous fungi. O-Linked glycosylation in filamentous fungi was seen to be highly conserved with many mannosyltransferases that are similar to those in S. cerevisiae. However, highly variable and diverse O-linked glycans also exist. We have developed a web resource for presenting the compiled data with user-friendly query options, which can be accessed at www.fungalglycans.org. This resource can assist attempts to remodel glycosylation of recombinant proteins expressed in filamentous fungal hosts.     

Phytoplankton morphological response to the underwater light conditions in a vegetated wetland

This study analyses the influence of the underwater light climate on the morphometric characteristics of the phytoplankton at the population and community levels. The differences in light conditions across the floodplain were mainly defined by the patchiness of floating macrophytes and humic acids concentration. A morphometric response at the community level to the underwater PAR was registered. Sites with strong light constraints were characterised by non-flagellated organisms or with a small proportion of unicellular flagellates. Short organisms (<10 μm) with a unit volume of less than 1,000 μm³ and a high surface:volume ratio (S/V >2) were the morphotypes related to poorly illuminated environments. Moreover, the organisms showed forms more slender under these limiting conditions. This pattern was different to that registered in well-illuminated sites where longer and larger organisms, with a smaller S/V and frequently flagellated, coexisted with the previously mentioned organisms. The autotrophic picoplankton, the smallest phytoplankton fraction, revealed lower abundances at sites with higher humic substances. Short term morphological changes were additionally studied for the dominant species by means of mesocosm experiments simulating different light climates. Intraspecific morphological plasticity was observed with respect to the filament length and the vacuolization of cells. Electronic Supplementary Material Supplementary material is available for this article at and is available to authorized users.