The non-pathogenic bacterium Mycobacterium smegmatis mc2155 has been widely used as a model organism in mycobacterial research, yet a detailed study about its transcription landscape remains to be established. Here we report the transcriptome, expression profiles and transcriptional structures through growth-phase-dependent RNA sequencing (RNA-seq) as well as other related experiments. We found: (1) 2,139 transcriptional start sites (TSSs) in the genome-wide scale, of which eight samples were randomly selected and further verified by 5′-RACE; (2) 2,233 independent monocistronic or polycistronic mRNAs in the transcriptome within the operon/sub-operon structures which are classified into five groups; (3) 47.50% (1016/2139) genes were transcribed into leaderless mRNAs, with the TSSs of 41.3% (883/2139) mRNAs overlapping with the first base of the annotated start codon. Initial amino acids of MSMEG_4921 and MSMEG_6422 proteins were identified by Edman degradation, indicating the presence of distinctive widespread leaderless features in M. smegmatis mc2155. (4) 150 genes with potentially wrong structural annotation, of which 124 proposed genes have been corrected; (5) eight highly active promoters, with their activities further determined by β-galactosidase assays. These data integrated the transcriptional landscape to genome information of model organism mc2155 and lay a solid foundation for further works in Mycobacterium.

BackgroundInflammation has been implicated in many disorders, including cancer and available therapies elicit adverse effects. Plants of the family Rubiaceae have shown potency against inflammation. The anti-inflammatory and anti-oxidant potential of Feretia apodanthera was investigated in this study to evaluate its effectiveness.MethodsThe phytochemical, antioxidant and anti-inflammatory potential of root bark (n-Hexane, diethyl ether, ethanol and aqueous) extracts of Feretia apodanthera was investigated in this study. The extracts were subjected to various chemical tests for phytochemical constituents; their antioxidant activity was determined using in-vitro DPPH radical scavenging activity assay and their anti-inflammatory activity was determined using carrageenan induced paw oedema model. FTIR and GCMS analysis was done to determine the compounds present.ResultsPhytochemical screening of extracts revealed the presence of unsaturated steroids, triterpenes, cardiac glycosides, tannins, saponin and alkaloids. Vitamin C had a median inhibitory concentration (IC50) of 0.038 mg/ml which was lower than IC50 of all the extracts. Of all the extracts, ethanol extract had the lowest IC50 (0.044 mg/ml) which is comparable to vitamin C. Anti-inflammatory studies showed that the inflammation inhibition potential of 400 mg/kg body weight of all the extracts was significantly lower (p < 0.05) than the standard ketoprofen (50 mg/kg) at the first three hours but significantly higher (p < 0.05) at the fourth hour. At the fifth hour, the inflammation inhibition potential of diethyl ether, ethanol and aqueous extracts were significantly higher (p < 0.05) than that of the standard. FTIR analysis showed the presence of ketones, amines, alkenes and carboxylic groups. GCMS analysis revealed compounds that are potential anti-inflammatory agents.ConclusionThis study revealed that extracts of Feretia apodanthera possess anti-inflammatory effects against right hind paw oedema of albino rats and can act as an effective antioxidant.

Under starvation conditions, bacteria tend to slow down their translation rate by reducing rRNA synthesis, but the way they accomplish that may vary in different bacteria. In Mycobacterium species, transcription of rRNA is activated by the RNA polymerase (RNAP) accessory transcription factor CarD, which interacts directly with RNAP to stabilize the RNAP-promoter open complex formed on rRNA genes. The functions of CarD have been extensively studied, but the mechanisms that control its expression remain obscure. Here, we report that the level of CarD was tightly regulated when mycobacterial cells switched from nutrient-rich to nutrient-deprived conditions. At the translational level, an antisense RNA of carD (AscarD) was induced in a SigF-dependent manner to bind with carD mRNA and inhibit CarD translation, while at the post-translational level, the residual intracellular CarD was quickly degraded by the Clp protease. AscarD thus worked synergistically with Clp protease to decrease the CarD level to help mycobacterial cells cope with the nutritional stress. Altogether, our work elucidates the regulation mode of CarD and delineates a new mechanism for the mycobacterial starvation response, which is important for the adaptation and persistence of mycobacterial pathogens in the host environment.

No abstract

The effect of 10% supplementation of fermented and unfermented Telfaira occidentalis and Gnetum africanum leaves for 21 days on haemoglobin-iron, haematological parameters and serum ferritin was investigated to determined if the leaves could replenish haemoglobin in iron deficient rats. Iron deficiency significantly (p<0.05) decreased the relative weight gain, haemoglobin-iron, serum ferritin, haemoglobin (Hb), and mean corpuscular haemoglobin concentration (MCHC), when compared to the iron sufficient control rats. Rats fed with T. occidentalis had a significantly (p<0.05) increased serum ferritin compared to those fed with G. africanum leaves. The levels of haematological parameters of rats in the iron deficient group were not significantly (p>0.05) different from the iron sufficient and leaves supplemented groups. However, haemoglobin concentration of rats on iron sufficient diet, fermented and unfermented T. occidentalis leaves and those treated with FeSO 4 were significantly (p<0.05) higher than that of rats in the iron deficient, fermented and unfermented G. africanum groups respectively. Percentage change in Haemoglobin-iron was lower for rats supplemented with the fermented forms of both leaves. This study shows that T. occidentalis has a significant (p<0.05) haemoglobin regeneration potential compared to G. africanum, and fermentation did not significantly (p>0.05) enhance the haemoglobin regeneration potential of both leaves.