LYCOPENE PRODUCTION IN MYCOBACTERIUM SMEGMATIS BY EXPRESSION OF CRT GENES FROM MYCOBACTERIUM AURUM AND PROTECTIVE EFFECT OF LYCOPENE IN VIVO AND IN VITRO AGAINST UV RADIATION

Objective: The aim of the present study was to express in Mycobacterium smegmatis the clustered mycobacterial genes coding for lycopene synthesis and to investigate the protective properties of lycopene against ultraviolet (UV) irradiation.Methods: The genes, which encode the biogenesis of lycopene in Mycobacterium aurum A+, were introduced into Mycobacterium smegmatis by electroporation. The pigments produced were analyzed by thin layer chromatography, and the absorption spectra were determined. A survival test using UV irradiations was also performed.Results: The transformed Mycobacterium smegmatis were found to synthesize lycopene with important yield (1.41± 3.09 mg/g) and was more resistant to ultraviolet irradiation than non-pigmented strain (p<0.01). Furthermore, cells of M. smegmatis not transformed but coated with lycopene are more resistant to UV than those uncoated (p<0.01).Conclusion: M. smegmatis can form orange colonies on agar plates when it is transformed with the lycopene genes, and the transformants produces 1.41 mg/g (dry weight) of this carotene. Our findings strongly suggest that lycopene has antioxidant activities and prevent the lethal action of UV irradiation on bacterial cells in vivo and in vitro, and deserves further studies considering the amelioration of the production

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

In vitro and intracellular antimycobacterial activity of a Bacillus pumilus strain

Despite the declaration of tuberculosis (TB) as a global emergency by the world health organization (WHO) about 20 years ago, the worldwide problem of this disease has worsened due to increased drug resistance of tuberculosis bacilli and acquired immune deficiency syndrome (AIDS) pandemic. Consequently, fight against multidrug and extensively drug-resistant TB is a high priority for public health and research. The present work describes the isolation of a Bacillus pumilus strain secreting a metabolite of protein nature capable of inhibiting mycobacterial growth (Mycobacterium smegmatis, Mycobacterium aurum and Mycobacterium bovis BCG). This metabolite is not toxic, accumulates within the macrophage and inactivates the bacilli with a comparable efficiency to that of the pure commercial antimycobacterial substance Amikacin

Isolation and identification of a Staphylococcus warneri strain with anti-mycobacterial activity

Tuberculosis is the principal cause of death from infection in the world. The resurgence of tuberculosis and the increase in mycobacterial infections, as well as multidrug-resistance of mycobacteria to available antibiotics, has incentivized research on new antimycobacterial agents. Therefore, research based on water and soil samples from the Moroccan biotopes, has led to the isolation of a bacterial strain capable of inhibiting mycobacterial growth (Mycobacterium smegmatis and Mycobacterium aurum A+). The effect was due to an active substance secreted into the culture medium. Sequencing of the 16S rRNA gene identified the strain as belonging to the species Staphylococcus warneri. The active substance precipitated using ammonium sulfate, maintained its inhibitory properties, which were lost when treated with proteinase K. These results indicated that the active substance was protein. Study of the activity of the metabolite revealed its effect on M. smegmatis cell wall, facilitating genomic DNA extraction.Keywords: Tuberculosis, mycobacteria, anti-mycobacterial agents, Staphylococcus warneri, DNA extraction.African Journal of Biotechnology Vol. 12(42), pp. 611

Biochemical characterization of a thermoactive and thermostable lipase from a newly isolated Trichosporon coremiiforme strain

Nonstop demand for greatly thermostable and thermoactive active lipase encourages the research for the new enzyme sources. In this study, a strain of Trichosporon coremiiforme was isolated from the traditional tannery in the city of Fez in Morocco, lipase production and their lipolytic activity was studied. Pure T. coremiiforme lipase (TCL) was obtained after ammonium sulfate fractionation, G-75 gel filtration and cation exchanger chromatography (Mono-S), having a molecular weight of 67 kDa. TCL presents a maximal activity at pH 8 and 50°C. After a 5 min treatment at 80°C, the enzyme maintained 50% of its activity, which is so far as is known. TCL previously characterized is found to be stable between pH 5 and 10 after 60 min incubation. TCL hydrolyses the long chains triacylglycerols more efficiently than the short ones. A specific activity of 1800 U/mg was measured on tributyrin or olive oil emulsion as substrate. This newly isolated lipase can be considered as a good candidature for industrial and biotechnological applications.Keywords: Trichosporon coremiiforme, lipase, purification, thermoactiveAfrican Journal of Biotechnology Vol. 12(28), pp. 4503-451

GATA4 molecular screening and assessment of environmental risk factors in a Moroccan cohort with tetralogy of Fallot

Background: Tetralogy of Fallot (TOF) is the most common cyanotic congenital heart defect (CHD) with an incidence of 1/3600 live births. This disorder was associated with mutations in the transcription factors involved in cardiogenesis, like Nk2 homeobox5 (NKX2-5), GATA binding protein4 (GATA4) and T-BOX1 (TBX1). GATA4 contributes particularly to heart looping and differentiation of the second heart field.Objectives: The aim of this study was to screen a Moroccan cohort with tetralogy of Fallot for GATA4 mutations, and to assess environmental risk factors that could be involved in the occurrence of this disorder.Methods: Thirty-one non-syndromic TOF patients, enrolled between 5th April 2014 and 18th June 2015, were screened for GATA4 mutations using direct sequencing of GATA4 coding exons. Statistical assessment of different risk factors, which is a retrospective study, was carried out using Chi-square and Fisher’s exact tests. Results: We identified seven exonic variants in nine patients (two missense and five synonymous variants); in addition of eight intronic variants. Assessment of environmental risk factors shows significant association of maternal passive smoking with TOF in the Moroccan population.Conclusion: The present study allowed, for the first time, the molecular and environmental characterisation of Moroccan TOF population. Our findings emphasise particularly the strong association of passive smoking with the emergence of tetralogy of Fallot.Keywords: Tetralogy of Fallot, GATA4, molecular screening, risk factors

Noonan syndrome-causing genes: Molecular update and an assessment of the mutation rate

AbstractNoonan syndrome is a common autosomal dominant disorder characterized by short stature, congenital heart disease and facial dysmorphia with an incidence of 1/1000 to 2500 live births. Up to now, several genes have been proven to be involved in the disturbance of the transduction signal through the RAS-MAP Kinase pathway and the manifestation of Noonan syndrome. The first gene described was PTPN11, followed by SOS1, RAF1, KRAS, BRAF, NRAS, MAP2K1, and RIT1, and recently SOS2, LZTR1, and A2ML1, among others. Progressively, the physiopathology and molecular etiology of most signs of Noonan syndrome have been demonstrated, and inheritance patterns as well as genetic counseling have been established. In this review, we summarize the data concerning clinical features frequently observed in Noonan syndrome, and then, we describe the molecular etiology as well as the physiopathology of most Noonan syndrome-causing genes. In the second part of this review, we assess the mutational rate of Noonan syndrome-causing genes reported up to now in most screening studies. This review should give clinicians as well as geneticists a full view of the molecular aspects of Noonan syndrome and the authentic prevalence of the mutational events of its causing-genes. It will also facilitate lay the groundwork for future molecular diagnosis research, and the development of novel treatment strategies

GATA4 molecular screening and assessment of environmental risk factors in a Moroccan cohort with tetralogy of Fallot

Background: Tetralogy of Fallot (TOF) is the most common cyanotic congenital heart defect (CHD) with an incidence of 1/3600 live births. This disorder was associated with mutations in the transcription factors involved in cardiogenesis, like Nk2 homeobox5 (NKX2-5), GATA binding protein4 (GATA4) and T-BOX1 (TBX1). GATA4 contributes particularly to heart looping and differentiation of the second heart field. Objectives: The aim of this study was to screen a Moroccan cohort with tetralogy of Fallot for GATA4 mutations, and to assess environmental risk factors that could be involved in the occurrence of this disorder. Methods: Thirty-one non-syndromic TOF patients, enrolled between 5th April 2014 and 18th June 2015, were screened for GATA4 mutations using direct sequencing of GATA4 coding exons. Statistical assessment of different risk factors, which is a retrospective study, was carried out using Chi-square and Fisher\u2019s exact tests. Results: We identified seven exonic variants in nine patients (two missense and five synonymous variants); in addition of eight intronic variants. Assessment of environmental risk factors shows significant association of maternal passive smoking with TOF in the Moroccan population. Conclusion: The present study allowed, for the first time, the molecular and environmental characterisation of Moroccan TOF population. Our findings emphasise particularly the strong association of passive smoking with the emergence of tetralogy of Fallot

Isolation, characterization and antimicrobial activity of a Streptomyces strain isolated from deteriorated wood

Emergence of drug resistance among pathogenic bacteria to currently used antibiotics has made the search for novel bioactive compounds from natural and unexplored habitats a necessity. In this study, we reported the isolation, characterization and antimicrobial activity of an actinomycete strain isolated from deteriorated wood of an old house located in the Medina of Fez. The isolate, named H2, was identified by 16S rDNA sequencing and was shown to belong to the genus Streptomyces. The isolate was screened for antimicrobial activity against Gram positive bacteria, Gram negative bacteria, Mycobacteria, yeasts and fungi. Partial characterization of the active substance (resistance to proteinase K and heat) showed that it would be of non-protein nature. The kinetics of production of the active substance showed that the maximum production occurs between the 7th and 10th day of fermentation. In addition, organic extract of the isolate was able to release genomic DNA of Staphylococcus aureus suggesting that it acts probably on the bacterial cell wall. Thin layer chromatography (TLC) of the ethyl acetate extract followed by bioautography has allowed localizing the active substances. This will open the way to further investigations to demonstrate their potential importance in combating pathogenic bacteria. Key words: Actinomycetes, Streptomyces, antimicrobial activity, molecular identification