Open Access Original Research Article

Microbiological Control of Bacterial Soft Rot Caused by Bacillus pumilus Od23 on Potato

Amadou Hamadoun Babana, Hamed Bathily, Fassé Samaké, Kadia Maïga, Diakaridia Traoré, Amadou Dicko

Microbiology Research Journal International, Page 41-48
DOI: 10.9734/BMRJ/2011/256

Potato soft rot, caused by Bacillus pumilus Od23, greatly affect potato tuber quality in storage and cultivars of Mali and indicated that it can affect all potato cultivars. Bacteria isolated from soil rhizosphere samples of healthy Malian indigenous trees were screened for their antagonistic effect against this pathogen. Three actinomycetes isolates (RoN, G1P, and N1F) were the most effective microbioagents in suppressing the growth of the pathogen. The biological control essay showed the possibility of controlling potato soft rot by these three actinomycetes isolates under conservation conditions. These treatments significantly decreased soft rot compared with the untreated potato tuber slices. The microbiological control results of this study suggest that the actinomycetes isolates RoN, G1P and and J1N are effective microbioagents in controlling soft rot of potato and could be considered as promising alternative to chemical products.

Open Access Original Research Article

Prevalence of Treponema pallidum Infection among Human Immunodeficiency Virus Seropositive Persons and Their Corresponding CD4 Counts in a Nigerian Cohort

G. R. Pennap, S. O. Osita, M. P. Adoga, G. Owuna, S. Agwale

Microbiology Research Journal International, Page 49-54
DOI: 10.9734/BMRJ/2011/319

Background: Sexually transmitted infections are a major public health problem especially with the advent of HIV/AIDS. This study was conducted to determine the prevalence of Syphilis among HIV seropositive persons. The study population was seropositive persons accessing antiretroviral therapy (ART) at the Federal Medical Center Keffi.
Methodology: Venous blood (5ml) was collected from each of the 200 consenting participants between February and August 2010. Their syphilis serostatus was determined using Rapid Plasma Reagin test and confirmed by an immunochromatographic rapid syphilis test kit. The CD4 count of the positive sample was also determined.
Results: Of the 200 persons screened, 56 were males and 144 were females. The prevalence of Treponema pallidum in this study population was 0.5% (1/200). The HIV-syphilis positive was a married man aged 35 years and with a CD4 cell count of ≥ 200 cells/uL.
Conclusion: This study reported a very low prevalence of syphilis among HIV positive persons. It is recommended that the sexual partner(s) of the study index case should be traced and also treated to prevent reinfection and/or continued spread of the infection. Despite the low prevalence in this study, syphilis screening among those with HIV should be advocated routinely to avoid the complications associated with the dual infection.

Open Access Original Research Article

The Structure and Metabolic Diversity of Population of Pea Microsymbionts Isolated from Root Nodules

Jerzy Wielbo, Monika Marek-Kozaczuk, Andrzej Mazur, Agnieszka Kubik-Komar, Anna Skorupska

Microbiology Research Journal International, Page 55-69
DOI: 10.9734/BMRJ/2011/412

Aims: The study of strains belonging to local rhizobial population, concerning their diversity in the genetic, metabolic and symbiotic properties, and their prevalence in the microsymbiont population.
Methodology: 257 rhizobial isolates recovered from nodules of five pea (Pisum sativum cv. Ramrod) plants grown at one site were classified using PCR-RFLP analysis of 16-23S rRNA ITS. After that, for representative group of 55 strains, 16-23S rRNA ITS region was sequenced, nodA-F region was analyzed by PCR-RFLP and sequencing, metabolic capabilities were studied using Biolog`s and growth tests and symbiotic performance in plant tests were assayed.
Results: Individual plants were infected by numerous and diverse strains, however, in the entire sampled population of microsymbionts, only three large clusters of strains could be distinguished on the basis of PCR-RFLP and sequence analyses of 16S-23S rRNA ITS region. Rhizobium strains belonging to different groups varied in plasmid number and the amount of plasmid DNA, utilization of carbon and energy sources, growth on soil extract-based media and the ability for symbiotic plant growth promotion. The most numerous group of the isolates was characterized by the high plasmid DNA content, low number of utilized sugar substrates, and comprised numerous strains with low symbiotic efficiency.
Conclusion: Sampled population of pea microsymbionts had its own characteristic structure with clearly distinguishable sub-populations, composed of numerous strains - probably descendants of a few old lineages, which diversified in the lapse of time. These strains are still competing during root nodule colonization, resulting in the symbiosis of individual pea plants with broad spectrum of different Rhizobium strains.

Open Access Original Research Article

In vitro Evaluation of Antibacterial Activity of Various Crude Leaf Extracts of Indian Sacred Plant, Ocimum sanctum L.

Pankaj Goyal, Purshotam Kaushik

Microbiology Research Journal International, Page 70-78
DOI: 10.9734/BMRJ/2011/312

The medical world is on an immense requirement to discover novel antibiotics due to widespread emergence of resistance among microbial pathogens against currently available antibiotics. Traditional plants have been proved to be better source in the search for novel antimicrobial compounds. In such effort, we accessed the susceptibilities of some clinically significant bacterial species against various extracts made up from leaves of Ocimum sanctum L. (family: Lamiaceae). Antibacterial activity of crude extracts was found to be reliant on the nature of extract and the bacterial strains evaluated. Methanol extract was found to have comparatively higher activity than other organic and aqueous extracts. Gram-positive bacteria showed variable susceptibilities while Gram-negative Salmonella typhi has shown to be completely resistance to all the tested extracts. Minimum inhibitory concentration data showed hopeful results as some of the extracts exhibited significant inhibitions of bacteria even at low concentrations. This study indicated that leaves of Ocimum sanctum L. have significant antibacterial activity and it could be very useful in the discovery of novel antibacterial/antimicrobial agents.