Anti-herpes simplex virus 1 and immunomodulatory activities of a poly-γ- glutamic acid from Bacillus horneckiae strain APA of shallow vent origin

Applied Microbiology and Biotechnology - Herpes simplex virus type 1 (HSV-1) is responsible of common and widespread viral infections in humans through the world, and of rare, but extremely severe,...     

Anoxybacillus thermarum sp. nov., a novel thermophilic bacterium isolated from thermal mud in Euganean hot springs, Abano Terme, Italy

A novel aerobe thermophilic endospore-forming bacterium designated strain AF/04^T was isolated from thermal mud located in Euganean hot springs, Abano Terme, Padova, Italy. Strain AF/04^T was Gram-positive, motile, rod-shaped, occurring in pairs, or filamentous. The isolate grew between 55 and 67°C (optimum 65°C) and at pH 6.0–7.5 (optimum pH 7.2). The strain was aerobic and grew on maltose, trehalose, and sodium acetate as sole carbon sources. The G + C content of DNA was 53.5 mol%. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain AF/04^T falls within the genus Anoxybacillus. Levels of 16S rRNA gene sequence similarity between strain AF/04^T and the type strains of recognized Anoxybacillus species ranged from 95 to 99%. Chemotaxonomic data (major isoprenoid quinone–menaquinone-7; major fatty acid iso-C15:0 and anteiso-C17:0) supported the affiliation of strain AF/04^T to the genus Anoxybacillus. Based on phenotypic and chemotaxonomic characteristics, 16S rRNA gene sequence analysis and DNA–DNA hybridization data, it was proposed that strain AF/04^T (=DSM 17141^T = ATCC BAA 1156^T) should be placed in the genus Anoxybacillus as the type strain of a novel species, Anoxybacillus thermarum sp. nov.     

Focus Issue on Roots: Root Nutrient Foraging

During a plant''s lifecycle, the availability of nutrients in the soil is mostly heterogeneous in space and time. Plants are able to adapt to nutrient shortage or localized nutrient availability by altering their root system architecture to efficiently explore soil zones containing the limited nutrient. It has been shown that the deficiency of different nutrients induces root architectural and morphological changes that are, at least to some extent, nutrient specific. Here, we highlight what is known about the importance of individual root system components for nutrient acquisition and how developmental and physiological responses can be coupled to increase nutrient foraging by roots. In addition, we review prominent molecular mechanisms involved in altering the root system in response to local nutrient availability or to the plant''s nutritional status.In natural and agricultural soils, the ability of plants to quickly and efficiently acquire nutrients may determine their competitive success and productivity. Because mineral elements interact differently with themselves and other soil constituents or are carried by water out of the rooted soil volume, their availability to plants may decrease and lead to nutrient deficiency. Under these conditions, plants activate foraging responses that include morphological changes, such as the modulation of root system architecture (RSA) or root hair formation, and physiological changes, such as the release of nutrient-mobilizing root exudates or the expression of nutrient transporters (Gojon et al., 2009; Hinsinger et al., 2009; Gruber et al., 2013). These responses are often spatially coupled to increase the root-soil interaction zone and improve the ability of the plant to intercept immobile nutrients. Noteworthy, although not discussed herein, symbiosis or associative rhizosphere microorganisms can also alter the RSA and enhance the foraging capacity of the plant (Gutjahr and Paszkowski, 2013). Here, we provide an update on the morphological responses induced by plants to forage sparingly available nutrients and some of the underlying molecular mechanisms known to date to be involved in RSA adaptations to nutrient availabilities.     

N-terminal cysteines affect oligomer stability of the allosterically regulated ammonium transporter LeAMT1;1

AMMONIUM TRANSPORTER (AMT) proteins are conserved in all domains of life and mediate the transport of ammonium or ammonia across cell membranes. AMTs form trimers and use intermolecular interaction between subunits to regulate activity. So far, binding forces that stabilize AMT protein complexes are not well characterized. High temperature or reducing agents released mono- and dimeric forms from trimeric complexes formed by AMT1;1 from Arabidopsis and tomato. However, in the paralogue LeAMT1;3, trimeric complexes were not detected. LeAMT1;3 differs from the other AMTs by an unusually short N-terminus, suggesting a role for the N-terminus in oligomer stability. Truncation of the N-terminus in LeAMT1;1 destabilized the trimer and led to loss of functionality when expressed in yeast. Swapping of the N-terminus between LeAMT1;1 and LeAMT1;3 showed that sequences in the N-terminus of LeAMT1;1 are necessary and sufficient for stabilization of the interaction among the subunits. Two N-terminal cysteine residues are highly conserved among AMT1 transporters in plants but are lacking in LeAMT1;3. C3S or C27S variants of LeAMT1;1 showed reduced complex stability, which coincided with lower transport capacity for the substrate analogue methylammonium. Both cysteine-substituted LeAMT1;1 variants showed weaker interactions with the wildtype as determined by a quantitative analysis of the complex stability using the mating-based split-ubiquitin assay. These data indicate that the binding affinity of AMT1 subunits is stabilized by cysteines in the N-terminus and suggest a role for disulphide bridge formation via apoplastic N-terminal cysteine residues.     

Geobacillus galactosidasius sp. nov., a new thermophilic galactosidase-producing bacterium isolated from compost

Two thermophilic spore-forming strains, with optimum growth temperature at 70 °C, were isolated from compost of the “Experimental System of Composting” (Teora, Avellino, Italy). A phylogenetic analysis based on 16S rRNA gene sequences showed that these organisms represented a new species of the genus Geobacillus. Based on polyphasic taxonomic data the strains represented a novel species for which the name Geobacillus galactosidasius sp. nov. is proposed. The type strain is CF1B^T (= ATCC BAA-1450^T = DSM 18751^T).     

Exopolysaccharide production by a new Halomonas strain CRSS isolated from saline lake Cape Russell in Antarctica growing on complex and defined media

A haloalkalophilic Halomonas strain CRSS, isolated from salt sediments in Antarctica, produced exocellular polysaccharides (EPS) up to 2.9gg^-1 dry cells. Acetate was the most efficient carbon source for EPS production. The composition of media strongly affected the nature of the polymers; a mannan and a xylo-mannan, were obtained when cells were grown on complex media. Acetate was the most efficient carbon source for EPS production and in presence of this substrate, a new polysaccharide, a fructo-glucan, was produced. The EPS fraction was composed by glucose, fructose, glucosamine and galactosamine in relative proportions of 1:0.7:0.3:trace.Revisions requested; Revisions received 6 September 2004     

Odoriferous compounds from the flowers of the conifers Picea abies,pinus sylvestris and Larix sibirica

A GC/MS analysis of the volatile constituents from the flowers of Norway Spruce, Picea abies, has been carried out. The volatile constituents of the female flowers were distinctly different from those of the male flowers and the twigs. Characteristic constituents are methyl and ethyl benzoate, methyl and ethyl salicylate, methyl and ethyl butanoate, borneol and bornyl acetate. In the scent from the male flowers we could only detect the same monoterpenes as in the twigs. In Larix sibirica methyl benzoate, methyl salicylate, borneol and bornyl acetate were detected in the female flowers and, in the female flowers of Pinus sylvestris, methyl salicylate was found.     

Production and characterization of exopolysaccharides by Geobacillus thermodenitrificans ArzA-6 and Geobacillus toebii ArzA-8 strains isolated from an Armenian geothermal spring

The thermal ecosystems, including geothermal springs, are proving to be source of thermophiles able to produce extracellular polysaccharides (EPSs). Among the sixteen thermophilic bacilli isolated from sediment sampled from Arzakan geothermal spring, Armenia, two best EPSs producer strains were identified based on 16S rRNA gene sequence analysis and phenotypic characteristics, and designated as Geobacillus thermodenitrificans ArzA-6 and Geobacillus toebii ArzA-8 strains. EPSs production was investigated under different time, temperature and culture media’s composition. The highest specific EPSs production yield (0.27 g g⁻¹ dry cells and 0.22 g g⁻¹ dry cells for strains G. thermodenitrificans ArzA-6 and G. toebii ArzA-8, respectively) was observed after 24 h when fructose was used as sole carbon source at 65 °C and pH 7.0. Purified EPSs displayed a high molecular mass: 5 × 10⁵ Da for G. thermodenitrificans ArzA-6 and 6 × 10⁵ Da for G. toebii ArzA-8. Chemical composition and structure of the biopolymers, determined by GC–MS, HPAE-PAD and NMR, showed that both the two EPSs are heteropolymers composed by mannose as major monomer unit. Optical rotation values [α] ^25 °C_D of the two EPSs (2 mg ml⁻¹ H₂O) were − 142,135 and − 128,645 for G. thermodenitrificans ArzA-6 and G. toebii ArzA-8, respectively.