Ambur, a town located on the banks of Palar River, is considered one of the most polluted areas in India and occupied by hundreds of tanneries and leather product units. The present study was designed to evaluate the toxic effect of discharged tannery effluent (TE) on model agricultural crops, ecofriendly microorganisms, and human blood cells. The phytotoxic effects of TE tested on Allium cepa and Lemna minor revealed inhibition of root growth and significant reduction in number of fronds, protein, and chlorophyll content. Moreover, TE induced chlorosis and tissue necrosis in Nostoc muscorum at low concentration (10%). TE has also negative impact on ecofriendly microorganisms, Bacillus thuringiensis, Rhizobium etli, and Aspergillus terreus which play an important role in the nutrition of plant growth. The genotoxicity of TE was investigated in human leukocytes which showed interference with normal mitotic division with subsequent cell lysis. It also intervened with the normal replication process and induced micronucleus formation in the healthy leukocyte. 5% concentration of TE has been revealed to be toxic to erythrocytes. From this study TE found in the Palar River of Ambur has adverse effects on all the three levels of organisms in ecosystem even at lower concentrations.

Arabian Sea is one of the most productive regions of the world's ocean with seasonal upwelling and a characteristic oxygen minimum zone. It receives a continuous input of windborne iron-rich dust which possibly stimulates phytoplankton productivity. A sediment core from this area, which is on the western continental margin of India in the Kerala-Konkan basin was studied from the surface to 63 meters below seafloor, to establish the co-occurrence of microbial iron reducing activity and methane oxidation. Total bacterial abundance (TC), viable aerobic counts accounting for aerobic and facultative anaerobes (TVCa), viable anaerobic counts (TVCan), methane, sulfate, ferrous [Fe(II], hydroxylamine extractable iron and HCl extractable iron concentrations were measured. Average TC was 52.6±29.8 x 10 5 cells g -1 sediment while TVCa and TVCan were an order less. Methane and sulphate concentrations were 1.3 ppm and 23.2 mM, respectively. Average Fe(II) concentration, hydroxylamine and HCl extractable Fe was 0.32±0.26, 0.86±1.44 and 1.90±2.47 mmol g -1 sediment, respectively. Interestingly, Fe(II) significantly correlated with TVCan (r=0.66, p≤0.001). In the experimental tubes, the build-up of Fe (II) was accompanied by the disappearance of methane. Average methane concentration and Fe (II) concentration in the experimental sediment slurries was 0.56±0.76 ppb and 0.50±0.27 mmol g -1 sediment respectively. The microcosm experiment showed that Fe (II) determined was significantly higher (ANOVA, F=6.74, p≤0.014) after 5 days of incubation, thus implying microbial iron reducing activity. A strong negative linear correlation (p≤0.001) of methane concentration with Fe (II) suggests that increasing activity of microbial iron reduction M A N U S C R I P TA C C E P T E D ACCEPTED MANUSCRIPT 2 caused suppression in methane production. This is also indicative of the co-occurrence of iron reduction and methane oxidation in these sediments.

Thrombolytic agents play a major role in the treatment of cardiovascular diseases. Streptokinase is the prominently commercialized thrombolytic drug used for the treatment of cardiovascular diseases. The later studies on staphylokinase (SaK) showed promising results as an alternative fibrinolytic drug. The present study explores the isolation, production and purification of SaK producing Staphylococcus sp. from milk samples. The potent isolate MSA4 of Staphylococcus sp. was selected for production and purification of SaK. The total activity and specific activity of purified staphylokinase was found to be 1266 IU mL(-1) and 815.5 IU mg(-1), respectively. The partially purified enzyme was lysed the euglobulin clot completely within 18 h of incubation and the purified enzyme showed 79% of blood clot lysis activity.