ABSTRACT
The objective of this study was to determine the distribution of genes encoding aminoglycoside‑modifying enzymes (AMEs) and staphylococcal cassette chromosome mec (SCCmec) elements among clinical isolates of methicillin‑resistant staphylococci (MRS). Antibiotic susceptibility test was done using Kirby–Bauer disk diffusion method. The presence of SCCmec types and AME genes, namely, aac (6’)‑Ie‑aph (2’’), aph (3’)‑IIIa and ant (4’)‑Ia was determined using two different multiplex polymerase chain reaction. The most encountered AME genes were aac (6′)‑Ie‑aph (2’’) (55.4%) followed by aph (3’)‑IIIa (32.3%) and ant (4’)‑Ia gene (9%). SCCmec type I (34%) was predominant in this study. In conclusion, the aac (6’)‑Ie‑aph (2’’) was the most common AME gene and SCCmec type I was most predominant among the MRS isolates.
ABSTRACT
The results of an investigation carried out during October 2005 to September 2006 on hydrography, composition and community structure of phytoplankton and zooplankton including chlorophyll ‘a’ (Chl-a) content and primary productivity (PP) at the Kaduviyar estuary (Southeast coast of India) are reported. Air and surface water temperatures (oC) varied from 23 to 29 and from 24 to 31 respectively while the light extinction coefficient values (LEC) ranged between 0.15 and 0.59. Salinity values (‰) varied from 4 to 34 and the pH ranged between 7.8 and 8.3. Variation in dissolved oxygen content was from 3.06 to 5.63 mg l-1. The ranges of inorganic nutrients (µM) viz., nitrate, nitrite, phosphate, silicate and ammonia were: 0.36-12.65; 0.06-1.86; 0.06-4.57; 17.96-235.06 and 0.001-0.75 respectively. The ranges of Chlorophyll ‘a’ (mg m-3) and the primary productivity (mgCm-3hr-1) values were: 3.4-12.8 and 55-119 respectively. Presently, 85 phytoplankton species representing different classes viz: Bacillariophyceae (58); Dinophyceae (16); Cyanophyceae (7); Chlorophyceae (3) and Chrysophyceae (1) were recorded. The phytoplankton density varied from 14,135 to 74,697 cells l-1, with peak diversity (3.46 bits ind.-1) during premonsoon season. The maximum density was found during summer season coinciding with the stable hydrographical conditions. Totally 92 species of zooplankton besides 18 larvae were recorded and the copepods formed the dominant group. The occurrence of most of the zooplankton species showed a distinct seasonal pattern, which was closely associated with the species-specific environmental conditions. That way the environmental factors exert major influence on the species composition, abundance and diversity of zooplankton. The zooplankton density (org. l-1) ranged between 4342 and 14,002 and between 4867 and 15,816 at stations 1 and 2 respectively. Kaduviyar estuarine waters were very rich in zooplankton diversity (bits ind.-1) viz: 5.29 at station 2 which was slightly higher than 5.27 at Station 1. Higher values of zooplankton density and species diversity were found during premonsoon and summer seasons and which showed positive correlation with salinity. The seasonal distribution and abundance of plankton are discussed in relation to hydrographical parameters.
ABSTRACT
The results of an investigation carried out during September 2002 to August 2003 on hydrography, composition and community structure of phytoplankton including chlorophyll ‘a’ (Chl-a) content and primary productivity (PP) of the Pichavaram mangrove (South-east coast of India) are reported. Atmospheric and surface water temperatures varied from 30.0 to 34.8oC and from 29.7 to 34.2oC respectively while the light extinction coefficient values (LEC) (K) ranged between 3.2 and 14.9. Salinity values varied from 9.6 to 35.4‰ and the pH ranged between 7.2 and 8.6. Variation in dissolved oxygen content was from 3.2 to 6.5 ml l-1. The ranges of inorganic nutrients viz., nitrate, nitrite, phosphate and silicate were: 7-36.23, 0.31-5.46, 0.28-3.70 and 12.26-56.64 μM respectively. Chlorophyll ‘a’ content ranged between 0.20 and 105.60 ;g l-1 and the ranges of gross and net primary productivities (PP) were: 16.54-826.8 and 11.52-610.2 mg C m-3 hr -1respectively. Presently a total of 94 species of phytoplankton were identified. Among these, the diatoms formed predominant group. Population density of phytoplankton varied from 400 to 3,21,000 cells-1. While the peak diversity (5.23 bits / ind.) of the phytoplankton was observed during summer season, the maximum population density was found during summer season coinciding with the stable hydrographical conditions.
ABSTRACT
An inhibitive assay of insecticides using Acetylcholinesterase (AChE) from the local fish Clarias batrachus is reported. AChE was assayed according to the modified method of Ellman. Screening of insecticide and heavy metals showed that carbofuran and carbaryl strongly inhibited C. batrachus AChE. The inhibition concentration (IC) IC50 values (and the 95% confidence interval) for both carbofuran and carbaryl inhibition on C. batrachus AChE at 6.66 (5.97-7.52) and 130.00 (119.3-142.5) μg l-1, respectively, was within the IC50 range of Electrophorus electricus at 6.20 (6.03-6.39) and 133.01 (122.40-145.50) μg l-1, respectively, and were much lower than bovine AChE at 20.94 (19.53-22.58) and 418.80 (390.60-451.60) μg l-1, respectively. The results showed that C. batrachus have the potential to be used as a cheaper and more readily available source of AChE than other more commercially available sources.
ABSTRACT
A diesel-degrading bacterium from Antarctica has been isolated. The isolate was tentatively identified as Pseudomonas sp. strain DRYJ3 based on partial 16S rDNA molecular phylogeny and Biolog® GN microplate panels and Microlog® database. Growth on diesel was supported optimally by ammonium sulphate, nitrate and nitrite. The bacterium grew optimally in between 10 and 15 oC, pH 7.0 and 3.5% (v/v) diesel. The biodegradation of diesel oil by the strain increased in efficiency from the second to the sixth day of incubation from 1.4 to 18.8% before levelling off on the eighth day. n-alkane oxidizing and aldehyde reductase activities were detected in the crude enzyme preparation suggesting the existence of terminal n-alkane oxidizing activity in this bacterium.
ABSTRACT
Background : Amino terminal pro-B-type natriuretic peptide (NT-proBNP) is a sensitive marker of ventricular dysfunction. Exercise causes an increase in the secretion of NT-proBNP; and with myocardial ischaemia the increase is more pronounced. This increase has been found to improve the diagnostic sensitivity of the stress ECG in diagnosing myocardial ischaemia in subjects with normal ventricular function. Objective : To assess whether the change in NT-proBNP can be used to diagnose effort-induced myocardial ischaemia in an unselected population. Methods : We enrolled a total of 51 consecutive patients; referred for exercise stress 99mTc-sestamibi SPECT MPI (single-photon emission computed tomography myocardial perfusion imaging) to diagnose inducible myocardial ischaemia. NT-proBNP was determined at rest and 30 minutes after cessation of exercise. Results : Of the 51 patients; 28 had normal perfusion scans; seven had scans with fixed perfusion defects (previous myocardial infarction with no inducible ischaemia) and 16 had reversible perfusion defects (inducible ischaemia). There was no correlation between ischaemia and resting NT-proBNP; post-stress NT-proBNP or the change in NT-proBNP (delta-NT-proBNP). Conclusion : In an unselected population the change in NT-proBNP cannot be used to diagnose effort-induced myocardial ischaemia