Mohammad Abdul Bakir

Pseudosporangium ferrugineum gen. nov., sp. nov., a new member of the family Micromonosporaceae.

An actinomycete strain 3-44-a(19)(T) was isolated from sandy soil collected in Bangladesh. The strain formed irregular pseudosporangia directly from aggregated spore chains above the rudimentary aerial mycelium. The pseudosporangia developed singly. Each pseudosporangium contained many small, non-motile, spherical, smooth-surfaced spores in chains. Strain 3-44-a(19)(T) contained meso- and 3-hydroxydiaminopimelic acid in the cell wall and MK-9(H(6)) as the major menaquinone and arabinose, galactose, glucose, mannose, ribose and xylose were present in the whole-cell hydrolysate. The diagnostic phospholipid was phosphatidylethanolamine and iso-C(15 : 0) (24.6 %), C(18 : 1)omega9c (15.5 %), C(16 : 0) (10.6 %), C(18 : 0) (9.4 %), iso-C(16 : 0) (8.6 %) and anteiso-C(15 : 0) (6.0 %) were detected as the major cellular fatty acids. The acyl type of the peptidoglycan was glycolyl and mycolic acids were not detected. The G+C content of the DNA was 73.6 mol%. The chemotaxonomic data indicated that the strain belonged to the family Micromonosporaceae. Phylogenetic analysis based on 16S rRNA gene sequence data also suggested that strain 3-44-a(19)(T) fell within the family Micromonosporaceae. On the basis of phylogenetic analysis and characteristic patterns of 16S rRNA gene signature nucleotides as well as morphological and chemotaxonomic data, this strain should be classified as a member of a new genus and species, Pseudosporangium ferrugineum gen. nov., sp. nov., in the family Micromonosporaceae. The type strain of Pseudosporangium ferrugineum is 3-44-a(19)(T) (=JCM 14710(T) =MTCC9007(T)).

Antiviral activities of streptomycetes against tobacco mosaic virus (TMV) in Datura plant: Evaluation of different organic compounds in their metabolites

A total of 20 strains of actinomycetes were isolated from Al-Kharj (K) and Al-Madina (M) areas in Saudi Arabia. Among these strains, six were selected for antiviral activity screening which are K1, K2, K3, M1, M2 and M3. All the selected strains were characterized morphologically to be under the genus Streptomyces. Primary and secondary screenings were performed against seven human pathogenic microorganisms such as Staphylococcus aureus ATCC 25923, Bacillus subtilis ATCC 6633, Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853, Salmonella suis ATCC 13076, Shigella sonnei ATCC 11060 and Candida albicans ATCC 1023. In the data, all the obtained six selected strains had shown a positive and very promising result with little variations. The bioactive compounds were extracted from the strains using solvent extraction methods. The tobacco mosaic virus (TMV) was obtained from tomato plants and the extract was prepared using a simple technique of homogenizing in water and filtration. Tobacco mosaic virus and the metabolites of streptomycetes strains were applied to the selected Datura metel plant leaves. After incubation for one week, it was found that the viral infection symptoms in the form of local lesions caused by the TMV were notably reduced on the plant leaves in the presence of bioactive metabolites. Further, in this study, gas chromatography-mass spectroscopy (GC-MS) analysis of all the crude metabolites of streptomycetes strains were performed for the determination of different compounds.

Actinomadura bangladeshensis sp. nov. and Actinomadura chokoriensis sp. nov.

The taxonomic position of two soil isolates, 3-46-b(3)(T) and 3-45-a(11)(T), was clarified based on data from a polyphasic study. The organisms showed a combination of chemotaxonomic and morphological properties typical of the genus Actinomadura. They formed distinct phyletic lines in the Actinomadura 16S rRNA gene tree and were closely associated with the type strains of Actinomadura meyerae (sequence similarity of 98.3-98.5 %), Actinomadura napierensis (98.1-98.3 %) and Actinomadura latina (96.4-96.8 %). The level of 16S rRNA gene sequence similarity between the new isolates was 99.1 %. The level of DNA-DNA hybridization between strains 3-46-b(3)(T) and 3-45-a(11)(T) was 43.6 % and levels of relatedness between the two new isolates and the type strains of A. meyerae and A. napierensis were 21.0-27.3 %. On the basis of phenotypic and genotypic properties, the new isolates could be differentiated from each other and from their closest phylogenetic relatives. It is proposed that the organisms be classified as representing two novel species of the genus Actinomadura. The names proposed for these taxa are Actinomadura bangladeshensis sp. nov. [type strain 3-46-b(3)(T) =JCM 13933(T) =MTCC8057(T)] and Actinomadura chokoriensis sp. nov. [type strain 3-45-a(11)(T) =JCM 13932(T) =MTCC8056(T)].

Microbacterium hatanonis sp. nov., isolated as a contaminant of hairspray

An aerobic, rod-shaped, Gram-positive, oxidase-negative, catalase-positive bacterial isolate, strain FCC-01(T), originating as a contaminant of hairspray was characterized using phenotypic and molecular taxonomic methods. A 16S rRNA gene sequence analysis revealed that the isolate belonged to the genus Microbacterium and represented an evolutionary lineage that was distinct from recognized Microbacterium species. Cell-wall hydrolysate from the isolate contained ornithine and the cell-wall sugars consisted of rhamnose and galactose. The main respiratory quinones were MK-12 (38 %) and MK-11 (35 %). The major cellular fatty acids were anteiso-C(15 : 0) (48 %), anteiso-C(17 : 0) (35 %) and iso-C(16 : 0) (11 %). The DNA G+C content was 69 mol%. The isolate showed <98 % 16S rRNA gene sequence similarity with respect to all of the Microbacterium species with validly published names. On the basis of the morphological, physiological and chemotaxonomic data and the results of the comparative 16S rRNA gene sequence analysis, this isolate represents a novel species of the genus Microbacterium, for which the name Microbacterium hatanonis sp. nov. is proposed. The type strain is FCC-01(T) (=JCM 14558(T) =DSM 19179(T)).

Studies of actinomycetes for biological control of Colletotrichum musae pathogen during post harvest anthracnose of banana

For the studies and preliminary screening, eighty actinomycetes isolates were selected as antagonists against Colletotrichum musae, causal agents of anthracnose of banana. Actinomycetes isolates were cultured with C. musae (dual culture) to determine their in vitro antagonistic ability. Seventeen strains that strongly inhibited hyphal growth of the pathogen were selected as potent antagonists. Green healthy fruits were treated with the test pathogen and potent antagonistic actinomycetes to determine their effective inhibition of pathogen. The selected actinobacterial isolates significantly reduced severity of anthracnose on artificially inoculated banana in storage conditions for one week incubation at about 30°C. Bioactive and potent isolates CF-1(1), Dir-10(10), Dir-10(4) and Dir-10(3) reduced the size of the lesion as compared to control. These streptomycetes isolates exhibited disease inhibition of 77 to 85% in the artificially inoculated banana fruits and maximum disease inhibition of 85.87% in banana was exhibited by the potent actinobacterial isolate Dir-10(10).

Proteolytic activity of alkaliphilic, salt-tolerant actinomycetes from various regions in Saudi Arabia

Actinomycetes were isolated from various desert soil samples of Saudi Arabia using alkaline and normal pH media. A total of 42 akaliphilic actinomycetes isolated from yeast extract-soluble starch (YS) agar media (pH 11.0 ± 1) and 102 actinomycetes were isolated from tap water agar media (pH 7.0 ± 1) for comparison. Aerial mycelium colours of actinomycetes were observed for the detection of strain varieties in the different soil samples from different areas. Colour types were more abundant in isolates grown tap water agar (TWA) than in isolates grown on YS agar medium (pH 11.0). On the TWA medium, there were 18 colour types of actinomycetes and on YS agar medium (pH 11.0) there were 10 colour types. The number of neutrophilic actinomycetes isolated in this study is higher than the alkaliphilic actinomycetes. Among the 42 alkaliphilic actinomycetes isolates, 30 isolates were salt tolerant alkaliphilic. Later about 16 alkaliphilic actinomycetes were screened on skim milk agar for preliminary proteolytic activity. A total of 10 isolates showed proteolytic activity. Of the 10 isolates, three isolates were alkaliphilic and seven isolates were salt-tolerant alkaliphilic. All the isolates need to be further studied for the ability of their potential protease enzyme production.

Prevotella falsenii sp. nov., a Prevotella intermedia-like organism isolated from monkey dental plaque.

Eight anaerobic, pigmented, non-spore-forming, Gram-negative, rod-shaped strains isolated from monkey oral cavities were characterized phenotypically and chemotaxonomically and their phylogenetic positions were determined using 16S rRNA gene sequence analysis. The 16S rRNA gene sequence analysis showed that these isolates represent a single species of the genus Prevotella. These strains were most closely related to Prevotella intermedia ATCC 25611(T), with 95.0 % 16S rRNA gene sequence similarity. The next most closely related species were Prevotella pallens and Prevotella nigrescens (92.7 and 92.1 % similarity to the respective type strains). The phenotypic and biochemical characteristics of the isolates were the same as those of P. intermedia JCM 12248(T) and P. nigrescens JCM 12250(T). The isolates could be differentiated from P. pallens JCM 11140(T) on the basis of mannose fermentation and alpha-fucosidase activity. The isolates could not be distinguished from P. intermedia or P. nigrescens using conventional biochemical tests. DNA-DNA hybridization experiments revealed the genomic distinctiveness of these eight strains with respect to P. pallens JCM 11140(T), P. intermedia JCM 12248(T) and P. nigrescens JCM 12250(T). On the basis of these data, strains 04013, 04021, 04043, 04052(T), 0406, 04113, 04111 and 04161 represent a novel Prevotella species, for which the name Prevotella falsenii sp. nov. is proposed. The type strain is 04052(T) (=JCM 15124(T) =CCUG 56137(T)).

Antifungal activity of some actinomycetes isolated from Riyadh soil, Saudi Arabia: An evaluation for their ability to control Alternaria caused tomato blight in green house pot trial

A collection of 105 strains of actinomycetes isolated from the soils of Riyadh, Saudi Arabia were evaluated for their ability to inhibit plant pathogenic Fusarium oxysporum, Alternaria alternata, Aspergillus niger, and Aspergillus flavus in vitro. About 61.90% isolates were able to inhibit the growth of A. alternata, followed by 61.8, 52.24 and 50.9% inhibiting A. flavus, F. oxysporum and A. niger respectively. Subsequently, these isolates were tested for their ability to control Alternaria blight on tomato plant (Lycopersicon lycopersicum) grown in sterilized peat moss soil. Broth and crude extract of all except, DS-8(32), DS-6(48) and DS-6(33) isolates of actinomycetes have shown effect on plant disease severity. Over all analysis of data showed that strain AS-2(29) was the most effective isolate.Broth and crude extract of this strain had shown maximum zone of inhibition against F. oxysporum (11 and 18 mm respectively) and A. alternata (15 and 17 mm respectively). Plants treated with this strain were healthy and green and only a few older leaves showed the blight symptom and growth was found at par with control plants. However, strain DS-6(33) has not shown any antifungal activity and plants succumbed to infection of A. alternata, whereas, broth of DS-8(24) and DS-1(23) showed strong antifungal activity against A. alternata (20 and 19 mm zone of inhibition). However, crude extract of these strains has not shown any antifungal activity and plants treated with these strains were healthy and only older leaves were blighted. Extract but not broth of DS-1(20) showed strong antifungal activity against F. oxysporum and A. alternata (15 and 16 mm respectively) and the growth of the plant was similar to that of the control plants in pot trial strains varied in their antifungal activity against one or both plant pathogenic fungi. Based on the cultural, morphological and physiological characteristics, most of the strains were identified as the different isolates of the genus Streptomyces. In the further study, Streptomyces species as biological control agents would be offered a much needed alternative to the use of synthetic agrochemicals. Key words: Actinomycetes, screening antifungal activity, A. alternata, green house pot trial, scanning electron microscope, tomato blight disease.

Antibacterial activities of the extracts of cyanobacteria and green algae isolated from desert soil in Riyadh, Kingdom of Saudi Arabia

In compliance to the recent surveys on algal species and their potentials to produce biologically active compounds, seven algal species belonging to cyanobacteria such as Spirulina platensis, Nostoc linckia, Phormidium autumnale, Tolypothrix distorta and Microcystis aeruginosa and green algae such as Chlorella vulgaris, and Dunaliella salina, were isolated from soil in Riyadh, Saudi Arabia. All algal species were morphologically identified using scanning electron microscopy, in addition to light microscopic analysis. Liquid media BG11 was used for cultivation of algal isolates for four weeks; chlorophylls were estimated in the exponential growth phase after two weeks growth in liquid BG11 medium; in liquid medium after four weeks incubation, maximum growth was recorded for Dunaliella salina and N. linckia using cell mass weight. Extraction of algal species were tested for antibacterial activity using agar well diffusion method against a variety of human pathogenic bacteria such as Salmonella suis ATCC 13076; Pseudomonas aeruginosa ATCC 27583; Escherichia coli ATCC 25922; Staphylococcus aureus ATCC 25923; Bacillus subtilis ATCC 6633; Shigella sonnei ATCC 11060 and one yeast Candida albicans ATCC 10231. The bioactive metabolites from algal species were extracted using three different solvent system as methanol: acetone: diethyl ether (5:2:1), acetone and ethanol. The methanol : acetone : diethyl ether solvent system was the most effective solvent system among the three and showed strong activity against S. sonnei, S. aureus, and B. subtilis. Ethanol extract of P. autumnale showed activity against only C. albicans. Key words : Algae isolation, scanning electron microscope, cyanobacteria, green algae, algal extract, antimicrobial activity, human pathogenic bacteria and yeast.