Enhancing systematic tolerance in Bermuda grass (Cynodon dactylon L.) through amplified alkB gene expression and bacterial-driven hydrocarbon degradation

This study aimed to access the impact of soil polluted with petroleum (5, 10 g petroleum kg-1 soil) on Bermuda grass (Cynodon dactylon L.) with and without applied bacterial inoculants (Arthrobacter oxydans ITRH49 and Pseudomonas sp. MixRI75). Both soil and seed were given bacterial inoculation. The evaluated morphological parameters of Bermuda grass were fresh and dry weight. The results demonstrated that applied bacterial inoculants enhanced 5.4%, 20%, 28% and 6.4%, 21%, and 29% shoot and root fresh/dry weights in Bermuda grass under controlled environment. The biochemical analysis of shoot and root was affected deleteriously by the 10 g petroleum kg-1 soil pollution. Microbial inoculants enhanced the activities of enzymatic (catalase, peroxidase, glutathione reductase, ascorbate peroxidase, superoxide dismutase) and non-enzymatic (ɑ-tocopherols, proline, reduced glutathione, ascorbic acid) antioxidant to mitigate the toxic effects of ROS (H2O2) under hydrocarbon stressed condition. The maximum hydrocarbon degradation (75%) was recorded by Bermuda grass at 5 g petroleum kg-1 soil contamination. Moreover, bacterial persistence and alkane hydroxylase gene (alkB) abundance and expression were observed more in the root interior than in the rhizosphere and shoot interior of Bermuda grass. Subsequently, the microbe used a biological tool to propose that the application of plant growth-promoting bacteria would be the most favorable choice in petroleum hydrocarbon polluted soil to conquer the abiotic stress in plants and the effective removal of polyaromatic hydrocarbons in polluted soil.

Factors identified for negative appendicectomies

The study was done, to determine the factors for negative appendicectomies. This prospective descriptive study includes patients managed at four non teaching and a teaching hospital of Karachi from March 2006 to February 2008. One hundred and sixty eight patients underwent appendicectomy during the study period. Details of clinical presentations, investigations, operative findings and histopathology were entered and analyzed. Literature search was aimed to see the negative appendicectomy rate (NAR) in last ten years despite using diagnostic tools (clinical scoring, diagnostic imaging and laparoscopy). In this study a total number of 168 patients under went appendicectomy. Normal appendices were found in 31 patients (negative appendicectomy rate was 18.45%) and associated pathology was seen in 13 patients, an incidental finding of Meckel's diverticulum in 5 patients and no other pathology was seen in 13 patients. The different factors which we identified for negative appendicectomies in our practice were non teaching hospitals where diagnostic scoring system was difficult to apply, female gender, selective use of imaging modality, other pathologies presenting with pain in right lower quadrant (RLQ) and requiring surgical intervention, and non-availability of CT scan and laparoscopy. Despite many advances in diagnostic system, acute appendicitis is still a diagnostic dilemma at times. Although there is no substitute for clinical judgment but in sub groups of patients in whom the possibility of negative appendicectomy is high, diagnostic modalities should be used judiciously to decrease the negative exploration.