Abdellah Houari

Isolation and identification of a staphylococal strain with an anti-mycobacterial activity and study of it’s mode of action

The resistance of mycobacteria to the clinical applied antibiotics poses a serious problem to deal with the infections they cause. So, the search for new antibiotics active against these bacteria becomes urgent. We report here the isolation from a Moroccan biotope of a bacterial strain secreting an active substance of protein nature that inhibits the growth of several mycobacterial species (Mycobacterium smegmatis; M. aurum A+;M. vaccae; M. bovis BCG andM. kansasii). PCR amplification and DNA sequecing of the 16S ribosomal RNA gene allowed the identification of this strain asStaphylococcus haemolyticus. Moreover, the substance produced by this strain was able to lyse the wall ofM. smegmatis and to extract its genomic DNA indicating that it acts probably, like others anti-mycobacterial antibiotics, on this envelope. The identification and characterisation of the active substance would open the way for further technological and therapeutic investigations.

Antimycobacterial activity of a Brevibacillus Laterosporus strain isolated from a moroccan soil

The treatment of tuberculosis has become more difficult with the worldwide spread of multidrug-resistant (MDR) and extensively drug-resistant (XDR) strains of Mycobacterium tuberculosis. Moreover, the prevalence of human disease caused by atypical mycobacteria has also increased in the past two decades and has further complicated the problem of the treatment of mycobacterial infections. It is therefore urgent to develop new highly active molecules against these bacteria. The present study reports the isolation from a Moroccan soil of a Bacillus strain that exhibits an important antimycobacterial activity. The strain was identified as Brevibacillus laterosporus using DNA sequencing of the 16S ribosomal RNA gene. The antimycobacterial activity was assigned to a substance with a protein nature. This nature was revealed using a liquid-liquid extraction with organic solvents, precipitation with ammonium sulfate and treatment with a protease. This study suggested the identification and the characterization of this active metabolite enabling therapeutic investigations further.

Aerococcus sp. with an antimycobacterial effect

Tuberculosis is an infectious disease that causes fatality every year because of drugs resistance of the Mycobacterium complex; this is why the development of new antibiotics becomes an urgent need. To reach that target, a main approach was led; consisting on screening of active substances producing microorganism. In this study, we reported data on a strain that was isolated from different areas of Fez (Morocco), which present an antagonistic effect against Mycobacterium smegematis and possessed a large spectrum against bacteria of Gram positive and negative. The antimycobacterial compounds producer, ZI1, was identified as Aerococcus sp. on the basis of PCR amplification of 16S ribosomal RNA gene followed by sequencing (99 and 100% of homology, respectively by RS16 and FD1), and by using biochemical tests, the unknown bacterium ZI1 was so close to either the species Aerococcus viridans or Aerococcus urinaeequi , but it was distinguishable from the other five Aerococcus species. The antimycobacterial compounds were synthesised in the exponential growth phase of Aerococcus sp. and were fully affected following heat treatment and protolytic enzymes which indicated the proteinaceous nature of the active agents. Key words : Tuberculosis, antimycobacterial compounds, Aerococcus sp

Yeast strains from the endogenous microflora of the olive fliesBactrocera oleae larvae which could degrade the olive oil mill wastewaters polyphenols

Worldwide, wastewaters constitute a major environmental pollutant. They are very toxic against a wide range of plants and soil microorganisms. Their toxicity is due to the presence of compounds such as polyphenols. In this study, we have isolated yeast strains from the endogenous microflora of the olive fliesBactrocera oleae larvae that were capable of degrading the olive oil mill wastewater polyphenols. The results obtained showed the presence, in the digestive tract of the larvae, of yeast strains resisting to polyphenols. Two resistant strains were isolated and have shown variable capacity of polyphenols degradation that could reach up to 72%. The two isolated strains were identified by two methods: conventional technique and molecular method associating PCR amplification and DNA sequencing of the 5.8S ribosomal RNA gene. Both techniques showed that the two isolated strains corresponded to theCandida diddensiae specie. Related to its capacity to degrade polyphenols, this specie would be a potential candidate for wastewater treatment and environmental protection.

Isolation and identification of Bacillus strains with antimycobacterial activity

Tuberculosis is the principal cause of death worldwide due to an infectious disease. The resurgence of tuberculosis, followed by the increase in prevalence of infections caused by nontuberculous mycobacteria (NTM), as well as the multi-drug resistance of mycobacteria to the majority of currently available antibiotics, have encouraged research for new antimycobacterial agents. Soil and water samples from different Moroccan biotopes, have led to the isolation of four bacterial strains ( M, R, G and S), showing an inhibitory effect on mycobacterial growth. This effect was shown to be due to secreted substances in the growth medium. From subsequent analysis it was concluded that these strains produced different active substances. Sequencing of the 16S rRNA showed that these isolates belong to the genus Bacillus . The active substance from isolate M, showed the more important inhibitory effect on mycobacterial growth. It is precipitated with ammonium sulfate and lost all activity when treated with Proteinase K, revealing its protein nature.

Partial purification and antimycobacterial screening of the ethyl acetate extract of Alcaligenes faecalis BW1.

Aims: The focus of this study was to evaluate the antimycobacterial activity of Alcaligenes faecalis BW1 extract and to purify it partially. Study design: Partial purification of A. faecalis BW1 extract was performed by using thin layer chromatography and active substances responsible for the biological activity were localized. Place and Duration of Study: The study was carried out at laboratory of Microbial Biotechnology, Department of Biology, Faculty of Sciences and Technical, University Sidi Mohamed Ben Abdellah, BP 2202, Road of Immouzer, Fez, Morocco, during the period from January 2011 to July 2011. Methodology: Crude extract of A. faecalis BW1 was obtained by using ethyl acetate as an organic solvent and its antimycobacterial effect was investigated by agar discs diffusion method. The extract was then fractionated by thin layer chromatography and the bioactivity was assessed with a bioautography technique followed by spots elution tests. Results: The results showed that A. faecalis BW1 produced compounds with antimycobacterial activity. All the detected spots by thin layer chromatography inhibited the growth of M. smegamtis. Original Research Article British Microbiology Research Journal, 4(11): 1178-1188, 2014 1179 Conclusion: Various metabolites of A. faecalis BW1 are responsible for the sought effect or they could act synergistically to inhibit mycobacterial growth. These compounds could be used after their total purification in further work against mycobacterial infections.

Antibacterial effect of bacillus strains and partial characterization of their extracts.

Aims: The focus of this study was to isolate and to identify strains with antibacterial activity followed by a partial characterization of their extracts. Study Design: Screening and identification of bacteria having an anti-mycobacterial effect from soil and water of different biotopes of Fez Morocco were performed and active substances responsible for the biological activity were partially characterized. Place and Duration of Study: The study was carried out at laboratory of Microbial Biotechnology, Department of Biology, Faculty of Sciences and Technical, University Sidi Mohamed Ben Abdellah, BP 2202, Road of Immouzer, Fez, Morocco, during the period from January 2011 to October 2011. Methodology: Samples of soil and water of different biotopes of Fez Morocco were explored to isolate compounds-producing microorganisms. The inhibitory spectrum of the isolated bacteria was evaluated against M. smegmatis, M. aurum, S. aureus, S. haemolyticus, B. subtilis, E. coli DH5 α, P. aeruginosa and Erwinia chrysanthemi by using agar well diffusion test and/or a modified spot-onlawn assay. Identification of strains was executed on the basis of Gram stain, biochemical characteristics and PCR followed by DNA sequencing of 16S ribosomal RNA gene. Crude extracts obtained after precipitation by ammonium sulfate were exposed to proteolytic enzymes (Pepsin and

Chemical Constituents of Essential Oils of Wood and Wood Veneers of Tetraclinis Articulate (Vahl) Masters from Morocco

Abstract The essential oils obtained separately from both the untreated and treated wood (wood veneer) of Tetraclinis articulate (Dahl) Masters gathered from the area of Essaouira (Morocco)have been analyzed using GC and GC-MS. Remarkable qualitative and quantitative differences were found between the constituents in the samples studied. In the treated wood, the main componentswere carvacrol (41.2 % vs. 30.5% for untreated wood), O-methylthymodroquinone (10.8 % vs. 16.5 % for untreated wood) and cedrol (2.5 % vs. 12.1 % for untreated wood). The present study shows that the wood veneers are source of essential oil and can be used in both medicinal and cosmetic purposes.