ABSTRACT
An investigation was made on total heterotrophic bacterial (THB) load in relation with hydrographical features of Pazhayakayal estuary, Tuticorin, from July 2009 to June 2010. The water temperature (25 to 32oC), pH (7 to 10), and salinity (0‰ to 35.7‰) were maximum during summer season (April - June) and minimum during monsoon season (October - December). The dissolved oxygen (do) varied from 0.2 to 9.95 mg l-1. The THB load was high (42.0?0-7cfu ml-1) during monsoon season and low (1.2?0-7cfu ml-1) during summer. The correlation was insignificant between temperature, pH and THB load, however THB load was negatively correlated with salinity. Almost in all the stations (I-VI), THB load were found to be maximum (40.0?0-7,36.0?0-7, 30.0?0-7,36?0-7, 42.0?0?0-7 and 29.6?0-7 cfu ml-1) during monsoon season might be due to the bulk rainfall and freshwater input.
ABSTRACT
This study was to compare the replication capacity of pneumococcal isolates (serotypes 1, 7F, 19F and 23F) with their adherence pattern to monolayer cells (A549). For standardization purposes, all isolates showed a normal growth curve in both bacteriological (THB + 0.5% yeast extract with and without 2% FBS) and cell culture media (RPMI + 2% FBS). In the former media, a shorter lag phase was observed for isolate serotypes 1 and 7F in presence of serum while in the later; growth yield was lower for all isolates with stationary phase approaching OD600 of 0.01 as compared to 1.0 in bacteriological media. In the replicative analysis at different growth phases of the isolates in cell culture media, growth capacity at 3 h post-incubation was frequently twice as that at 1 h, and that at early-log phase was frequently higher than that at mid-log phase at both post-incubation times. Adherence was frequently the least at early-log phase although the isolates were in the most active state of replication to increase the number of pneumococcal cells to adhere. At mid- and late-log phases, pneumococcal adherence was frequently higher although the replication was reduced. This study marks the potential correlation between pneumococcal growth fitness and adherence capacity whereby the later may not be superior during the early growth phase.
ABSTRACT
Microorganisms play a vital role in the biogeochemical cycles of various marine environments, but studies on occurrence and distribution of such bacteria in the marine environment from India are meager. We studied the phosphate solubilizing property of bacteria from the deep sea sediment of Bay of Bengal, India, to understand their role in phosphorous cycle (and thereby the benthic productivity of the deep sea environment). Sediment samples were obtained from 33 stations between 10 degrees 36'N-20 degrees 01' N and 79 degrees 59' E-87 degrees 30' E along 11 transects at 3 different depths i.e. ca. 200 m, 500 m, 1000 m in each transect. Total heterotrophic bacterial (THB) counts ranged from 0.42 to 37.38 x 10(4) CFU g(-1) dry sediment weight. Of the isolates tested, 7.57% showed the phosphate solubilizing property. The phosphate solubilizing bacterial genera were Pseudomonas, Bacillus, Vibrio, Alcaligenes, Micrococcus, Corynebacterium and Flavobacterium. These strains are good solubilizers of phosphates which ultimately may play a major role in the biogeochemical cycle and the benthic productivity of the Exclusive Economic Zone (EEZ) of Bay of Bengal, because this enzyme is important for the slow, but steady regeneration of phosphate and organic carbon in the deep sea.