Seedlings of tropical leguminous tree Samanea saman (Jacq.) Merrill were exposed for 7 d to acidic mist (AM, induced by H 2 SO 4 ) of pH 5.6, 4.0, and 2.0. AM significantly reduced seedling growth (root and shoot length, leaf density, leaf area, fresh and dry mass accumulation) and photosynthetic activities. In thylakoids isolated from leaves treated at pH 4.0 and 2.0 a decrease in the activities of photosystem (PS) 2 and whole chain electron transport was observed, but PS1 activity did not change. When the seedlings were subsequently sprayed with triacontanol (TRIA), the AM effect was partially or completely reversed indicating that TRIA can protect from AM effects. The artificial electron donors, diphenylcarbazide (DPC) and hydroxylamine (NH 2 OH), markedly restored the loss of PS2 activity in AM (pH 2.0) treated leaves. This is the first report of alleviating the AM by TRIA in tropical tree seedlings.

No abstract

Two colonial ascidians Didemnum granulatum and D. psammathodes were collected from Tuticorin coastal waters. These ascidians were sequenced at 603 and 576 bp region of the mitochondrial cytochrome oxidase subunit I gene (COI) for phylogenetic analysis. Barcode sequences were extracted via FASTA format from NCBI. The genetic distances of submitted DNA sequences were compared with related ascidian species. Didemnum granulatum (JQ013198) sequence shows maximum identical 99% with D. vexillum. Didemnum psammathodes (JN624758) sequence submitted at present shows maximum identical 100% with another D. psammathodes sequence which was already submitted in NCBI. The sequence also shows maximum identical 90-89% with D. vexillum. From the present study it is concluded that precise and accurate identification of ascidians could be performed using the barcode sequences of the mitochondrial DNA (in the COI gene).

No abstract

The present study was carried for evaluate the antimicrobial properties of different solvent extracts of ascidian Didemnum granulatum against human, fish pathogenic and biofilm microbes. In this study anti microbial activities were carried out by standard disc diffusion method. In this experiment 50 human, fish bacterial, fungal pathogens and biofilm microbes were isolated and assayed against 7 different solvents such as methanol, acetone, ethanol, n-butanol, chloroform, ethyl acetate and dichloromethane. Each solvent assayed at different concentrations 25, 50, 75 and 100 mgmL-1. The ascidian extracts exhibits profound antibacterial activity against human, fish pathogens and biofilm microbes. The higher concentration of solvents showed higher inhibition of bacterial pathogens but the fungal pathogens show resistant to tested solvents. The ascidian D. granulatum could be an ideal candidate for antimicrobial lead molecule development against microbial pathogens.