Isolation, characterization, and hydrolytic activities of Geobacillus species from Jordanian hot springs

The present study was conducted to isolate, identify, characterize and to determine the enzymatic activities of the thermophilic Geobacillus species from five Jordanian hot springs. Based on phenotypic characters, eight thermophilic isolates were identified and belonged to the genus Geobacillus. The Geobacillus isolates were abundant in all investigated hot springs. The optimal temperature for growth of the isolates was 60 to 65°C and the optimal pH was 6 to 8. Colonies were light yellow circular to rhizoid. The bacterial cells were Gram positive rods and endospore forming. All isolates produced amylase, caseinase, alkaline and acid phosphatases, esterase (C4), esterase lipase (C8), α-Galactosidase, β-Glucuronidase, β-Glucosidase, and N-Acetyl-β-glucosaminidase. Seven isolates produced leucine and valine arylamidases and five isolates produced naphthol-AS-B1- phsphohydrolase. Lipase (C14) activity from two isolates and α-chymotrypsin activity from three isolates were also detected. The phenotypic characterization of those isolates was confirmed by genotypic method using 16S rDNA sequence analysis. Maximal homology of all eight  isolates to genus Geobacillus was observed. Five of these isolates showed greater than 98% homology with Geobacillus stearothermophilus and one isolate showed 100% homology with Geobacillus thermoglucosidasius. Therefore, 16S rRNA gene sequence analysis can be considered as a valuable genotypic tool for the identification and characterization of thermophilic bacteria at genus level. Moreover, enzymatic products of those isolates could receive considerable attention due to their potential applications in biotechnology.Keywords: Thermophiles, Geobacillus, hydrolytic enzymes, hot spring, 16S rRNA

Efficacy of <em>Bacillus thuringiensis jordanica</em> against <em>Meloidogyne javanica</em> Infecting Tomato

A local strain of Bacillus thuringiensis jordanica (Btj), serotype H71, was evaluated for its efficacy in controlling Meloidogyne javanica attacking tomato. Glasshouse experiments were conducted using a soil drench of the bacterium applied one week before transplanting the tomato seedlings to the soil. Results showed a reduction in tomato root galling by 51–59% when M. javanica eggs or second stage juveniles (J2) were used as inoculum respectively. Single (14 days) and double (14 and 7 days) applications of Btj before plantation, both achieved a significant reduction in root galling. A field trial also showed that Btj, alone or in combination with peptone, significantly reduced root galling

Antimicrobial activity of Streptomyces sp. isolated from the gulf of Aqaba-Jordan and screening for NRPS, PKS-I, and PKS-II genes

Forty-nine Streptomyces isolates were recovered from sediment samples in the gulf of Aqaba/Jordan. All isolates were tested for antimicrobial activity against Gram positive bacteria, Gram negative bacteria, and yeast. Twenty eight Streptomyces isolates were active against at least one of the tested strains. The majority of the isolates showed activity against Gram positive bacteria: Streptomyces aureus (89%), Streptomyces epidermidis (64%) and Bacillus Subtilis (50 %). Lower activity was observed toward Gram negative bacteria with only 25% active against Pseudomonas aeruginosa, whereas only 17% were active against the yeast Candida albicans. Isolate S34 showed best activity. It produced heat stable antimicrobial activity at both acidic and alkaline pH (5 to 5.5 and 8 to 9.5). S34 was found to be related to Streptomyces rochei. Forty-nine Streptomyces isolates were screened for genes encoding non ribosomal peptide synthetases (NRPS) and polyketides synthases (PKS; types I and II). NRPS sequences were widely distributed and detected in 81% of Streptomyces isolates. PKS types I and II were detected in 63.2 and 65.3% of isolates, respectively. Additionally, the relationship between the occurrences of biosynthetic gene sequences (NPRS and PKS sequences) and the production of antimicrobial activities was determined. The above results reveal that the marine Streptomycetes are a promising source of novel and unique products.Keywords: Marine Streptomyces, antimicrobial activity, non ribosomal peptide synthetases (NRPS), polyketides synthases (PKS), enzymes, gulf of Aqaba, JordanAfrican Journal of Biotechnology, Vol 13(31) 3505-351

Genetic relationship in the "Bacillus cereus group" by rep-PCR fingerprinting and sequencing of a Bacillus anthracis-specific rep-PCR fragment

Aims: To evaluate the genetic relationship in the Bacillus cereus group by rep-PCR fingerprinting. Methods and Results: A collection of 112 strains of the six species of the B. cereus group was analysed by rep- PCR fingerprinting using the BOX-A1R primer. A relative genetic distinctness was found among the species. Cluster analysis of the rep-PCR patterns showed clusters of B. thuringiensis strains quite separate from those of B. cereus strains. The B. anthracis strains represented an independent lineage in a B. cereus cluster. The B. mycoides, B. pseudomycoides and B. weihenstephanensis strains were clustered into three groups at some distance from the other species. Comparison of sequences of AC-390, a typical B. anthracis rep-PCR fragment, from 27 strains of B. anthracis, B. cereus, B. thuringiensis and B. weihenstephanensis, representative of different clusters identified by rep-PCR fingerprinting, confirmed that B. anthracis diverges from its related species. Conclusions: The genetic relationship deduced from the rep-PCR patterns indicates a relatively clear separation of the six species, suggesting that they can indeed be considered as separate units. Significance and Impact of the Study: rep-PCR fingerprinting can make a contribution in the clarification of the genetic relationships between the species of the B. cereus group