Occurrence of Phosphate-Solubilizing Bacteria in Rhizospheric and Pneumatophoric Sediment of Avicennia marina

The present study deals with the isolation and characterization of phosphorus-solubilizing bacteria (PSB) from Avicennia marina rhizospheric sediment, pneumatophoric sediment and non-rhizospheric sediment. The sampling was carried out in four mangrove forests of Mumbai, India. The physicochemical parameters like pH, electrical conductivity, organic carbon, texture, total Phosphorus (P), inorganic P, organic P, Olsen P, iron, calcium, magnesium and zinc in sediment were analysed along with the isolation and molecular characterization of PSB. Significantly, lower pH was observed in the rhizospheric sediment than in the pneumatophoric and bulk sediment. Abundance of PSB was also found in the rhizospheric zone. This was supported by other physicochemical parameters such as high organic P, Olsen P, and higher bacterial count along with low inorganic P. In this study, 8 PSB were isolated and 16S rDNA sequence revealed that all the isolates belong to the genus Bacillus. Among the PSB isolates, B. subtilis sub. spizizenii TU-B-10 showed significantly higher solubilization activity (85.8±0.0 µg P released per 108 cfu in 72 hrs). The isolates that showed higher phosphate-solubilizing potentials can be explored as phosphatic bio-fertilizer to enhance the agricultural, aquacultural and mangrove productivity

Growth performance of Spirulina (Arthrospira) platensis in a low cost medium: An assessment

The unialgal culture of Spirulina platensis was sub-cultured in Zarrouk’s medium under photoautotrophic conditions. Initially, indoor batch cultivation was carried out for a week in four different types of cultivation media viz., Zarrouk’s, Modified Zarrouk’s, prescribed Nallayam Research Centre (NRC), and Modified NRC. In modified medium, urea and phosphoric acid of NRC medium were replaced with sodium nitrate and dipotassium hydrogen phosphate (anhydrous) and concentration of ferrous sulphate heptahydrate was reduced. The batch and airlift indoor culture experiments were carried out with an illumination of 3500±100 lux, photoperiod of 12:12 hour light and dark periods and temperature of 24±1°C. The specific growth rate value was 5.7 % higher in Zarrouk’s medium as compared to modified NRC medium. However, the cost of modified NRC medium was considerably lower than Zarrouk’s medium; therefore, modified NRC medium was selected for outdoor studies. The outdoor mass cultivation was done under natural conditions with the solar radiation reaching the surface of culture was between 2160 and 8450 lux and temperature ranged from 27 to 34°C. An assessment of the performance of growth in batch, airlift and FRP (Fiber Reinforced Polymer) tanks revealed that culture grown in airlift units showed best growth which was evident from higher specific growth rate and number of doublings per day. There was a 3.4-fold increase in cell density (in terms of turbidity at 750 nm) of the cultures in such units. The growth in outdoor FRP tanks was also comparable to the airlift cultures

Animal hygiene and sustainable livestock production: impact of ground water contamination with arsenic

There is a growing concern all over the world about contamination of ground water with Arsenic. One of the major repercussions of arsenic contamination is degradation of animal hygiene that ultimately affects sustainable livestock production. The reports suggest that concentration of Arsenic in ground water of twenty one countries is well above the guideline values. Use of such contaminated water for animal husbandry and livestock production compromises with the hygienic value of animal products. Therefore, there is an urgent need to develop low cost treatment technologies for reducing the level of arsenic in ground water to maintain the hygiene and sustainability of livestock production. Most of the traditional treatment technologies are costly and less effective in reducing arsenic concentration to safer limits. Therefore, during present study, an attempt was made to design a low-cost algal adsorbent based filtration unit consisting of polyurethane columns with entrapped algal adsorbents. The column was made of adsorbents of algal origin like agar-agar, alginic acid, calcium alginate and Spirulina platensis biomass entrapped in polyurethane foam matrix. The performance of the column was assessed in terms of removal efficiency and the quantity of metal sequestered in unit time interval. The results from the study the show that algal biosorbents and S. platensis biomass combination has a capacity to adsorbed arsenic from aqueous solution. The simple design, easy fabrication and no energy requirement for the operation of the filtration unit developed under the present study is suitable to rural areas where arsenic contamination of ground water is adversely affecting the animal hygiene and sustained livestock production

Occurrence and Abundance of Phosphatase-Producing Bacteria in Mangrove Ecosystem

The study detailed the isolation and characterization of phosphatase producing bacteria (PPB) from rhizospheric, pneumatophoric and bulk sediments of Avicennia marina along Mumbai coast, India and also estimated alkaline phosphatase activity in sediment in addition to the Phosphatase enzymatic activity of isolates. The inorganic-organic nature of phosphorus was also examined. About, 42 PPB were isolated and identified from the sediment samples. 16S rDNA sequence revealed that all the isolates belong to the genus Bacillus except the one which belong to Geobacillus in the environment and B. anthracis str. Ames showed the phosphatase-producing activity of 84.11±0.01 µg p-NP released per 1×108 cfu in 72 hrs. The isolates, B. cereus strain APT23 and B. thuringiensis strain INRS4 showed the next best phosphatase activity. It was observed that PPB was very much abundant in A. marina mangroves. The pneumatophoric sediment showed significantly higher number of PPB with higher alkaline phosphatase activity, inorganic P and low organic P than those of other sediment types indicating that pneumatophoric region of A. marina harbours favourably the phosphatase-producers than the rhizospheric or bulk sediments and forms the first reference worldwide depicting this relationship. The isolates that showed higher phosphatase-producing potentials can be explored for using as phosphatic bio-fertilizer to enhance the agricultural, aquacultural and mangrove productivity on a larger scale

Influence of sediment chemistry on mangrove-phosphobacterial relationship

The study reveals importance of sediment chemistry in mangrove-phosphobacterial relationship. The various physicochemical parameters of sediment, bacterial distribution, and acidic- alkaline phosphatase activity were studied in Avicennia marina mangrove sediments. The sampling sites were four mangrove forests along West India. Rhizospheric, pneumatophoric and bulk/non-rhizospheric sediment were collected. The rhizospheric sediment showed higher bacterial activity. The pH was observed low in the rhizospheric sediment and good abundance of phosphate-solubilizing bacteria (PSB). This was also supported by other physico-chemical parameters. Acid phosphatase activity was found to be higher in rhizospheric sediment indicating acid production at rhizosphere by microbial action and root exudation. It is the first study indicating that alkaline phosphatase activity was observed to be higher in pneumatophoric sediment. This coincides with higher number of phosphatase-producing bacteria (PPB) and high inorganic P in the pneumatophoric sediment, revealing that this region of A. marina harbours favourably more PPB with utilization of organic P by bacterial load and conversion to inorganic forms stressing that strong bonding exists between mangrove-sediment-phosphobacterial relationships

Note on Occurrence of Jaydia queketti (Osteichthyes: Apogonidae) from the Bycatch of Tropical Trawl Fishery

Three specimens of apogonids species of total length 72.69, 106.28 and 110.67 mm were caught off Tuticorin at the depths of 90-100 m as a bycatch on 1st January 2013 from the commercial trawler operated from Tuticorin Fishing Harbour, Southeast coast of India. In this paper, on the occurrence of Jaydia queketti was figured and the comprehensive diagnostic features of the recorded specimens were elucidated. The species of this genus Jaydia is distributed continentally and often caught as a bycatch from shrimp or fish trawl. These species are widely distributed in New Guinea, larger islands in the Coral Sea, Australia, Arabian Sea of India and also from Africa to Japan. Nevertheless, the present observation shows the occurrence of J. queketti from the bycatch of trawl fishery operated along Gulf of Mannar, Southeast coast of India

The adult heart responds to increased workload with physiologic hypertrophy, cardiac stem cell activation, and new myocyte formation

Aims It is a dogma of cardiovascular pathophysiology that the increased cardiac mass in response to increased workload is produced by the hypertrophy of the pre-existing myocytes. The role, if any, of adult-resident endogenous cardiac stem/progenitor cells (eCSCs) and new cardiomyocyte formation in physiological cardiac remodelling remains unexplored. Methods and results In response to regular, intensity-controlled exercise training, adult rats respond with hypertrophy of the pre-existing myocytes. In addition, a significant number (∼7%) of smaller newly formed BrdU-positive cardiomyocytes are produced by the exercised animals. Capillary density significantly increased in exercised animals, balancing cardiomyogenesis with neo-angiogenesis. c-kitpos eCSCs increased their number and activated state in exercising vs. sedentary animals. c-kitpos eCSCs in exercised hearts showed an increased expression of transcription factors, indicative of their commitment to either the cardiomyocyte (Nkx2.5pos) or capillary (Ets-1pos) lineages. These adaptations were dependent on exercise duration and intensity. Insulin-like growth factor-1, transforming growth factor-β1, neuregulin-1, bone morphogenetic protein-10, and periostin were significantly up-regulated in cardiomyocytes of exercised vs. sedentary animals. These factors differentially stimulated c-kitpos eCSC proliferation and commitment in vitro, pointing to a similar role in vivo. Conclusion Intensity-controlled exercise training initiates myocardial remodelling through increased cardiomyocyte growth factor expression leading to cardiomyocyte hypertrophy and to activation and ensuing differentiation of c-kitpos eCSCs. This leads to the generation of new myocardial cells. These findings highlight the endogenous regenerative capacity of the adult heart, represented by the eCSCs, and the fact that the physiological cardiac adaptation to exercise stress is a combination of cardiomyocyte hypertrophy and hyperplasia (cardiomyocytes and capillaries)

Importance of Spin-Orbit Interaction for the Electron Spin Relaxation in Organic Semiconductors

Despite the great interest organic spintronics has recently attracted, there is only a partial understanding of the fundamental physics behind electron spin relaxation in organic semiconductors. Mechanisms based on hyperfine interaction have been demonstrated, but the role of the spin-orbit interaction remains elusive. Here, we report muon spin spectroscopy and time-resolved photoluminescence measurements on two series of molecular semiconductors in which the strength of the spin-orbit interaction has been systematically modified with a targeted chemical substitution of different atoms at a particular molecular site. We find that the spin-orbit interaction is a significant source of electron spin relaxation in these materials

Assessment of heavy metals distribution in a coastal environment of Versova coast, Mumbai, India

The existence of heavy metals namely, copper, chromium, and cadmium was studied in coastal waters off Versova, Mumbai. Monthly sampling was carried out from October 2012 to March 2013 across 36 stations. Concentrations of Copper (Cu), Cadmium (Cd) and Chromium (Cr) were measured using the Atomic Absorption Spectrophotometry (AAS). The concentration of dissolved elements in surface water varied from 0.01 to 0.03 mg/l. Concentrations of dissolved elements in sub-surface waters were as follows: Cu (0.01 to 0.02 mg/l), Cd (0.02 to 0.03 mg/l) and Cr (0.02 to 0.03 mg/l). The concentrations of Cu, Cd and Cr in suspended solids of the surface water were 0.82 – 1.68, 5.22 – 10.24 and 3.26 – 16.03 mg/kg, respectively, while their concentrations in suspended solid obtained from the sub-surface water were 2.77 – 4.29, 3.24 – 10.10 and 1.91 – 5.67 mg/kg, respectively. The concentrations of Cu, Cd, and Cr in sediments were 74.52 – 112.81, 3.02 – 22.88 and 65.05 – 107.74 mg/kg, respectively. The physico-chemical parameters of water and sediment were analyzed to understand the temporal distribution of heavy metals