Bacterioplankton was studied in a large area of Southwest Atlantic Ocean between 13 and 25oS and 28 and 42oW. Samples were collected in 108 stations at 20 m depth. Bacteria were enumerated by flow cytometry after nucleic acid staining with syto13 and two subgroups were differentiated: low nucleic acid content (LNA) and high nucleic acid content (HNA) bacteria. Total bacterial numbers varied fro...

In photosynthesis, the pigments chlorophyll a/b absorb light energy to convert to chemical energy in chloroplasts. Though most enzymes of chlorophyll biosynthesis from glutamyl-tRNA to chlorophyll a/b have been identified, the exact composition and regulation of the multimeric enzyme Mg-protoporphyrin IX monomethyl ester cyclase (MPEC) is largely unknown. In this study, we isolated a rice pale-...

Results from an innovative approach to improve remediation in the rhizosphere by encouraging healthy plant growth and thus enhancing microbial activity are reported. The effect of arbuscular mycorrhizal fungi (Am) on remediation efficacy of wheat, mungbean and eggplant grown in soil spiked with polyaromatic hydrocarbons (PAH) was assessed in a pot experiment. The results of this study showed th...

Coastal eutrophication may be a vital inducement of green tide. Denitrification is an important nitrogen removal pathway that involves series enzymatic reactions. The rate-limiting step in the conversion nitrite to nitric oxide encoded by two functionally equivalent but structurally distinct genes, copper-containing reductase gene ( nirK ) and cytochrome cd1-containing nirS ). Here, we used Ill...

Plant growth-promoting rhizobacteria (PGPR) are naturally occurring soil bacteria that aggressively colonize plant roots and benefit plants by providing growth promotion. Inoculation of crop plants with certain strains of PGPR at an early stage of development improves biomass production through direct effects on root and shoots growth. Inoculation of ornamentals, forest trees, vegetables, and a...

Chlorella vulgaris was tested to assess their toxicities in freshwater contaminated by the metal compounds of copper (Cu) and cadmium (Cd), both singly and combined. Exposure to 0.5 and 1.5 M Cu or 1.0 and 2.0 M Cd alone significantly decreased algal growth and chlorophyll content and increased reactive oxygen species (ROS) content. Two-way ANOVA analysis shows that the combination of these two...

Bacteria are known to influence domoic acid (DA) production by Pseudo-nitzschia spp., but the link between DA production and physiology of diatoms requires more investigation. We compared a toxic P. multiseries to a non-toxic P. delicatissima, investigating links between DA production, physiological parameters, and co-occurring bacteria. Bacterial communities in cultures of both species were re...

the effects of plant growth promoting rhizobacteria (pgpr) on growth and physiological characteristics of seedlings corylus avellana were determined in a forest nursery. for this purpose, in a completely randomized design (crd) and four replicates, three putative bacteria, including pseudomonas putida, bacillus subtilis and enterobacter cloacae, as alone and mixed, were examined. the greatest h...