Rhizobacterial population density and nitrogen fixation in seagrass community of Gulf of Mannar, India.

Seagrass rhizosphere generally supports high bacterial population density which plays a major role in determining the nutrient cycles of the sea. Higher densities of total heterotrophic bacteria (26.3 ?06 CFU g-1), nitrogen fixing (27.3 ?03 CFUg-1), ammonifying (44.66 X 106 MPN g-1) and nitrifying bacteria (42.33 X 106 MPN g-1 ) have been registered in the seagrass areas than the non seagrass area. In particular, all these rhizosphere microbial population was higher in Thalassia hemprichii. The rates of nitrogen fixation was recorded in the different species of seagrasses such as Enhalus acoroides (1.166 n mol g-1d-1), Halophila ovalis (0.166 n mol g-1d-1), Thalassia hemprichii (18.5 n mol g-1d-1), Cymodocea serrulata (10.5 n mol g-1d-1), Halodule uninervis (5.375 n mol g-1d-1) and Syringodium isoetifolium (0.666 n mol g-1d-1) using gas chromatography. The average nitrogen fixation by the seagrasses of Gulf of Mannar alone was estimated to be 7640.58 n mol m-2 d-1 and the contributions from the rhizosphere microbes will increase the quantity to many fold.

Extrauterine Intrapartum Treatment (EXIT) in bilateral primary fetal hydrothorax.

Primary Foetal Hydrothorax (PFHT), is an intrathoracic collection of fluid in the fetus, which may be present on either side or even bilaterally. Advances in foetal diagnostics now allow consideration of the Ex-utero Intrapartum Treatment (EXIT) procedure for PFHT. Ex-utero Intrapartum Treatment (EXIT) allows therapeutic interventions on the neonate while maintaining fetoplacental circulation and thereby maintaining oxygenation. We report two cases of bilateral PFHT managed successfully with EXIT procedure.

Studies on phytoplankton diversity in response to abiotic factors in Veeranam lake in the Cuddalore district of Tamil Nadu.

The phytoplankton samples were collected from the Veeranam lake for a period of one year from March-2005 to February-2006. The physico-chemical parameters of water such as air-temperature, water temperature, pH, salinity, dissolved oxygen, electrical conductivity and total dissolved solids were observed and their ranges were: 30.1-36.5 degrees C, 29.0-34.4 degrees C, 7.9-8.4, 1.2-2.5 mgl(-1), 7.6-9.2 microS and 2.5-5.2 mgl(-1). Totally 160 species of phytoplankton belonging to different taxonomic groups were identified. Among these 74 species to belong to Bacillariophyceae, 43 species to Chlorophyceae, 38 species to Cyanophyceae and 5 species to Euglenophyceae. The phytoplankton density was high (1705 cells l(-1)) during the summer season and low (760 cells l(-1)) during the winter season. Bacillariophyceae formed the dominant group. Species diversity index (H'), species richness (SR) and species evenness (J') were calculated.

Phosphate solubilizing actinomycetes in the estuarine environment: an inventory.

Sediment samples were collected from different stations of the Vellar estuary for isolation of total actinomycetes and phosphate solubilizing actinomycetes. Phosphatase activity in the sediments was also investigated Consistently a higher number of actinomycetes, phosphate solubilizing actinomycetes and phosphatase activity were recorded from the clay sediments than the sandy sediments at all the stations. In all, 7 strains showed positive phosphatase activity. Among them, one strain PS-3 exhibited good activity and was further investigated for optimum phosphorus solubilization at different pH (6, 6.5, 7, 7.5 and 8) and incubation (1st day to 20th day) periods. The solubilizing activity was maximum at the pH 7 and an incubation period of 13 days was required for an appreciable quantity of phosphorus to be leached into the medium. Based on the chemotaxonomical and conventional methods of identification, the strain PS-3 has been tentatively identified as Streptomyces galbus. The present study indicates that phosphatase enzyme and S. galbus along with other actinomycetes species would play a major role in solubilizing the phosphate in the estuarine ecosystem and increasing the soluble phosphate concentration thereby enhancing the productivity

Partial purification and anti-leukemic activity of L-asparaginase enzyme of the actinomycete strain LA-29 isolated from the estuarine fish, Mugil cephalus (Linn.).

The actinomycete strain LA-29 isolated from the gut contents of the fish, Mugil cephalus of the Vellar estuary showed excellent L-asparaginase activity The enzyme was purified 18-fold and the final recovery of protein was 1.9%, which exhibited an activity of 13.57 IU/mg protein. The partially purified L-asparaginase inhibited the growth of leukemia cells in male wistar rats. Average survival period of the rats was more in an optimum enzyme dose of 100 units and the survival period was less when the dosages were increased and at the same time the enzyme became less effective when the dosages were decreased. Higher survival of 17.2 days was recorded when 100 units of the enzyme was given in three intermittent doses (50/25/25 units) at the interval of 24 hr. Analysis of cell components of the strain LA-29 has revealed the wall type-I which is the characteristic of the genus Streptomyces. Further the morphological, physiological and biochemical features along with the micromorphological results obtained for the strain LA-29 were compared with that of the Streptomyces species found in Bergey's Manual of Determinative Bacteriology and the strain LA-29 has been tentatively identified as Streptomyces canus.

Studies on L-asparaginase enzyme of actinomycetes isolated from estuarine fishes.

Actinomycetes were isolated from different organs viz. skin, gills and gut contents of three species of fishes viz. Mugil cephalus (Linnaeus, 1758), Chanos chanos (Forskal, 1775) and Etroplus suratensis (Bloch, 1780) using three different media from the Vellar estuary, situated along the southeast coast of India. Among the three fishes, M. cephalus harboured highest number of actinomycetes population in all the three body parts examined followed by C. chanos and E. suratensis. Out of the three body parts of all fishes, gut contents had highest actinomycetes population followed by gills and skin. Among the three media used for isolation of actinomycetes, Kuster's agar medium was found to be suitable than the starch casein agar and glucose asparagine agar media. Out of the 40 strains isolated, only six strains (LA-2, LA-8, LA-15, LA-20, LA-29 and LA-35) showed significant L-asparagianse activity and were taken up for further studies. Impact of various physical and chemical factors such as pH, temperature, sodium chloride concentration, carbon sources and amino acids on the growth of actinomycetes and L-asparaginase activity was also studied. Optimum growth and enzyme activity was noticed under pH 7 to 8, temperature 37 degrees C, 1-2% sodium chloride concentration, sucrose as carbon source and without any amino acids. Analysis of the cell components of the isolated strains has revealed the wall type-I (the wall type-I is typical for the genus Streptomyces) and the strains were micromorphologically similar to the genus Streptomyces. Hence, the morphological, physiological and biochemical along with the micromorphological results obtained for the L-asparaginase producing strains were compared and the strains were tentatively identified as Streptomyces aureofasciculus (LA-2), S. chattanoogenesis (LA-8), S. hawaiiensis (LA-15), S. orientalis (LA-20), S. canus (LA-29) and S. olivoviridis (LA-35).

Optimum conditions for L-glutaminase production by actinomycete strain isolated from estuarine fish, Chanos chanos (Forskal, 1775).

Actinomycetes were isolated from skin, gills and gut contents of estuarine fish. Chanos chanos using Kuster's agar medium. Out of 20 strains tested, the strain LG-10 which was tentatively identified as Streptomyces rimosus showed L-glutaminase activity. Optimum production of L-glutaminase enzyme (17.51 IU/ml) was observed after 96 h of incubation at 27 degrees C, pH 9 and glucose and malt extract as carbon and nitrogen sources, respectively. The present study indicated scope for the use of S. rimosus as an ideal organism for the industrial production of extracellular L-glutaminase.

Neonatal Kawasaki disease.

The authors report a case of Kawasaki disease that manifested in a newborn and presented at the age of 6 weeks of age with coronary artery aneurysms.

Emergency transcatheter balloon recanalization of acutely thrombosed modified Blalock-Taussig shunts.

BACKGROUND: Modified Blalock-Taussig shunts are used to palliate a variety of cyanotic heart diseases associated with reduced pulmonary blood flow. Acute shunt thrombosis in patients with shunt-dependent pulmonary blood flow can result in life-threatening hypoxia. We describe our experience of emergency transcatheter recanalization in 5 severely hypoxic children with acute shunt occlusion. METHODS AND RESULTS: Five patients with ages ranging between 5 and 24 months (median 11 months) and weight ranging from 4 to 8 kg (median 5 kg) presented with severe hypoxia, acidosis and hypotension following acute occlusion of modified Blalock-Taussig shunts placed 11 days to 12 months ago. As severe hypoxia (saturation range 3 5%-5 0%), acidosis and a state of shock in all the patients increased the risk for a redo surgical procedure, they were taken up for emergency transcatheter recanalization within 2-6 hours of hospitalization. This was done by positioning a Judkin's right coronary catheter at the mouth of the thrombosed shunt, crossing the shunt with a guidewire and serial dilatations with coronary and/or peripheral angioplasty balloons to the size of the graft. This technique was immediately successful in 4 of the 5 patients, thereby avoiding a repeat palliative operation. In 2 patients with residual stenosis, stents were used to restore luminal patency. One patient with acute stent thrombosis was managed successfully with local delivery of thrombolysis for 36 hours, which resulted in good luminal patency. At follow-up after 6 and 12 months, the shunts in both the stented patients are patent, with an oxygen saturation of 78% and 80%, respectively. In 2 other patients who had undergone plain balloon angioplasty, the shunts remained patent for 11 days (died of bronchopneumonia and septicemia) and 3 months, respectively. The procedure was unsuccessful in one very sick patient in whom the shunt had a tortuous course. CONCLUSIONS: Transcatheter recanalization of an acutely thrombosed Blalock-Taussig shunt is feasible. It can offer satisfactory short-term palliation in selected patients. Stents may play a role in patients with residual narrowing after dilatation. The procedure can be expeditiously accomplished in an emergency situation in a severely hypoxic child and may be a realistic alternative to surgery or thrombolysis.

Operative outcome and intermediate term follow-up of neonatal Blalock-Taussig shunts.

BACKGROUND: The neonatal age group is considered to be one of the important risk factors for perioperative morbidity and mortality as well as poor long-term patency following Blalock-Taussig shunts. METHODS AND RESULTS: Out of a total of 190 patients who underwent Blalock-Taussig shunts in our institute between July 1998 and July 2000, 20 patients were aged less than 30 days and this neonatal cohort was studied retrospectively. The mean age was 18+/-11 days (range: 3-30 days). The mean weight of the babies was 3.1+/-0.7 kg, the smallest weighed 2.1 kg. The cardiac anatomy was tetralogy of Fallot with pulmonary atresia in 6, pulmonary atresia with intact ventricular septum in 3, tricuspid atresia in 5 and complex single ventricle physiology in the rest. All patients were deeply cyanotic and preoperative prostaglandin E1 was needed in 10 patients to ensure ductal patency and maintain oxygen saturations prior to the shunt operation. The mean hilar right and left pulmonary artery sizes were 3.99+/-0.44 mm and 3.69+/-0.79 mm, respectively. Three patients (15%) had significant stenosis at the site of duct insertion. The shunts were accomplished with 3.5 mm polytetrafluoroethylene grafts in 7 patients (35%) and 4 mm in the rest. The mean duration of mechanical ventilation was 2.0+/-2.83 days, one patient who developed bronchopneumonia needed prolonged ventilation for 14 days. The mean intensive care unit stay was 4.79+/-2.66 days. The mean hospital stay was 11.7+/-6.4 days. Five patients who developed sepsis stayed beyond 14 days. There were 3 deaths (immediate post-operative shock and possibly shunt malfunction in 1, bronchopneumonia in 1 and late shunt thrombosis at 3 months in 1). Two patients had late shunt block, one of those mentioned above and the other at 3 months secondary to infective endarteritis of the right pulmonary artery. All these infants received 4 mm grafts. All the 3.5 mm grafts were patent at follow-up. Seventeen patients were alive and well at follow-up (mean: 9 months, range: 3-21 months) with a mean resting systemic oxygen saturation of 77% (66%-95%). CONCLUSIONS: The overall shunt patency rate after neonatal Blalock-Taussig shunt is about 80% on intermediate term follow-up. A smaller graft size (3.5 mm) does not appear to be an incremental risk factor for shunt blockade and operative mortality.