Khalid M. Hameed

Microbial populations of crude oil spill polluted soils at the Jordan-Iraq desert (the Badia region)

Microbial populations’ inhabitants in crude petroleum contaminated soils were analyzed in relation with the soil characteristics. A noticeable greater decline of bacterial counts and diversity but a prevalence of the genus Pseudomonas over the other identified genera in the fresh contaminated soils as compared to the old ones was observed.

Antibacterial activity of Orobanche cernua extract.

The effect of the parasitic plant Orobanche cernua extract was evaluated on 5 different Gram‐positive and Gram‐negative bacteria. Dilution experiments show that the minimum inhibitory concentration (MIC; μg/ml) of the extract was as follows: Staphylococcus aureus — 1526.5; Streptococcus sp. — 3125; Streptococcus pyogenes — 25000 and both for Bacillus cereus and Escherichia coli‐50000 μg/ml. Data indicated that the MIC of 3125 μg/ml is equal to cefotaxime (30 μg) and tobromycin (10 μg) activity against Streptococcus sp. and S. aureus, respectively; 25000 and 50000 μg/ml is equal to cefotaxime (30 μg) activity against S. pyogenes and B. cereus, respectively, and 50000 μg/ml is equal to nalidixic acid (30 μg) activity against E. coli. It can be concluded that the O. cernua extract displays remarkable activity against some Gram‐positive bacteria such as Streptococcus and Staphylococcus.

Detection, identification and morphological characteristic of Macrophomina phaseolina: the charcoal rot disease pathogens isolated from infected plants in Northern Jordan

This is the first report about charcoal rot disease in Jordan. Twenty-five Macrophomina phaseolina isolates were collected from infected plants showing typical symptoms of charcoal rot disease. All of the 25 M. phaseolina isolates were pathogenic to cucumber plants under green house effect. The amplification of the isolated DNA from the 25 pathogenic fungal cultures using ITS specific primers (ITS 1 + ITS 4) showed a single band of 580 bp. There was a significant variation of their mycelial linear growth rate on PDA medium. The 25 M. phaseolina isolates showed a wide heterogeneity in their mycelium colour, microsclerotia distribution, pycnidia formation and chlorate phenotypes. Based on the morphological characterisation, the 25 isolates were grouped into seven different groups as indicated in a dendrogram of their morphological variation. The overall means similarity matrix of the 25 M. phaseolina recovered isolates were 0.58. The means of similarity matrix of the 25 M. phaseolina was in between 0.83 and 0.14. The similarity coefficient between the 25 isolates varies between 0.27 and 1.0.

Estimation of Jordanian isolated Pectobacterium cellulase, pectinase concentrations, RAPD polymorphism and their maceration activity

Forty-two Pectobacterium isolates were recovered from contaminated soil and rotted vegetables in Jordan. Twenty of them were belonged to; Pectobacterium carotovorum subsp. Carotovorum (Pbc) (= Erwinia carotovora subsp. carotovora), 11 isolates were belonged to Pectobacterium atrospeticum (= Erwinia carotovora subsp. atroseptica) (Pba) and 11 isolates were not classifiable (Pbs). Maceration activity of the 42 proved their ability to macerate potato, carrot and radish slices. Maceration activity of the isolates either of the same subspecies or in between the isolates of different subspecies isolated from the same host or from different hosts was varied. The measured concentration in μM ml−1 of both cellulase and pectinase enzymes was variable too. The Rapid amplified polymorphic DNA-PCR finger printing of total genomic DNA using a pair of 10-mer oligonucleotide primers amplification showed similar DNA bands with some polymorphic variations amongst the isolates.