Response of bacterioplankton to iron fertilization of the Southern Ocean, Antarctica.

Ocean iron fertilization is an approach to increase CO2 sequestration. The Indo-German iron fertilization experiment "LOHAFEX" was carried out in the Southern Ocean surrounding Antarctica in 2009 to monitor changes in bacterial community structure following iron fertilization-induced phytoplankton bloom of the seawater from different depths. 16S rRNA gene libraries were constructed using metagenomic DNA from seawater prior to and after iron fertilization and the clones were sequenced for identification of the major bacterial groups present and for phylogenetic analyses.

Vertical distribution of bacteria in a lake sediment from Antarctica by culture-independent and culture-dependent approaches.

Bacterial diversity of the subsurface (18-22 cm), middle (60-64 cm) and bottom (100-104 cm) of a 136-cm-long sediment core sampled from a freshwater lake in Antarctica was determined by the culturable approach, T-RFLP and 16S rRNA gene clone libraries. Using the culturable approach, 41 strains were isolated and, based on phylogenetic analysis, they could be categorized into 14 groups. Representatives of the 14 groups varied in their growth temperature range (4-30 °C), in their tolerance to NaCl (0-2 M NaCl) and in the growth pH range (5-11).

Synthesis and conformational studies of peptides from new C-linked carbo-beta-amino acids (beta-Caas) with anomeric methylamino- and difluorophenyl moieties.

New C-linked carbo-beta-amino acids (beta-Caas), Cbz-(S)-beta-Caa-(NHBoc)-OMe (1) and Cbz-(R)-beta-Caa-(NHBoc)-OMe (2), with an additional amine group (methylamino group of NHBoc) at the C-1 position of the lyxofuranoside side chain and Boc-(S)-beta-Caa-(diFP)-OMe (3) and Boc-(R)-beta-Caa-(diFP)-OMe (4), with a C-difluorophenyl (diFP) moiety at the anomeric position of the lyxofuranoside side chain were prepared from D-mannose. Beta-peptides [tetra- and hexapeptides] were synthesized from these beta-Caas, 'epimeric' [at the amine stereocentre (C(beta))], using the concept of 'alternating chirality' to carry out their conformational studies [NMR (CDCl(3)), CD and MD]. In the monomer design, it was envisaged that the presence of an additional amine group in 1 or 2 would help in solubilizing the peptides in water, while, the C-difluorophenyl (diFP) moiety of 3 and 4 is expected to enhance the biological activity.

Comparative chemical characterization of pigmented and less pigmented cell walls of Alternaria tenuissima.

Alternaria tenuissima, the parasitic fungus, was obtained from the pruned upper-cut surfaces of mulberry stems. This fungus contains dark pigment because of the presence of melanin in the cell wall. To obtain less-pigmented cell walls, this fungus was grown under dark condition.