| 1. |
- Ghosh, Jaydip, et al.
(författare)
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Sporulation in mycobacteria
- 2009
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - 0027-8424 .- 1091-6490. ; 106:26, s. 10781-10786
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Tidskriftsartikel (refereegranskat)
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| 2. |
- Ghosh, Jaydip, et al.
(författare)
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Sporulation in mycobacteria
- 2009
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 106:26, s. 10781-10786
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Tidskriftsartikel (refereegranskat)abstract
- Mycobacteria owe their success as pathogens to their ability to persist for long periods within host cells in asymptomatic, latent forms before they opportunistically switch to the virulent state. The molecular mechanisms underlying the transition into dormancy and emergence from it are not clear. Here we show that old cultures of Mycobacterium marinum contained spores that, upon exposure to fresh medium, germinated into vegetative cells and reappeared again in stationary phase via endospore formation. They showed many of the usual characteristics of well-known endospores. Homologues of well-known sporulation genes of Bacillus subtilis and Streptomyces coelicolor were detected in mycobacteria genomes, some of which were verified to be transcribed during appropriate life-cycle stages. We also provide data indicating that it is likely that old Mycobacterium bovis bacillus Calmette-Guérin cultures form spores. Together, our data show sporulation as a lifestyle adapted by mycobacteria under stress and tempt us to suggest this as a possible mechanism for dormancy and/or persistent infection. If so, this might lead to new prophylactic strategies.
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| 3. |
- Pettersson, B. M. Fredrik, et al.
(författare)
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Identification and expression of stressosomal proteins in Mycobacterium marinum under various growth and stress conditions
- 2013
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Ingår i: FEMS Microbiology Letters. - : Oxford University Press (OUP). - 0378-1097 .- 1574-6968. ; 342:2, s. 98-105
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Tidskriftsartikel (refereegranskat)abstract
- Like other bacteria, Mycobacterium spp. have developed different strategies in response to environmental changes such as nutrient limitations and other different stress situations. We have identified candidate genes (rsb genes) from Mycobacterium marinum involved in the regulation of the activity of the alternative sigma factor, sigma F. This is a homolog of the master regulator of general stress response, sigma B, and the sporulation-specific sigma factor, sigma F, in Bacillus subtilis. The organization of these genes in M.marinum and B.subtilis is similar. Transcriptome and qRT-PCR data show that these genes are indeed expressed in M.marinum and that the levels of expression vary with growth phase and exposure to stress. In particular, cold stress caused a significant rise in the expression of all identified rsb and sigF genes. We discuss these data in relation to what is currently known for other Mycobacterium spp.
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| 4. |
- Shariful Islam, Md, et al.
(författare)
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Cigarette smoking and associated factors among men in five South Asian countries: A pooled analysis of nationally representative surveys
- 2022
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Ingår i: PLOS ONE. - : PLoS. - 1932-6203. ; 17:11
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Tidskriftsartikel (refereegranskat)abstract
- Smoking is one of the leading causes of premature deaths worldwide. The cigarette is the commonest form of tobacco smoking. This study investigated the factors associated with cigarette smoking among men in five South Asian countries. We analyzed nationally representative cross-sectional study (Demographic and Health Survey) data conducted in Afghanistan, India, Maldives, Nepal, and Pakistan from 2015–2018. Our study population was men aged between 15 and 49 years. The outcome variable was the prevalence of cigarette smoking. We performed both pooled and country-specific analyses using multivariable logistic regression. The prevalence of cigarette smoking among men is the highest (41.2%) in the Maldives and the lowest (20.1%) in Pakistan. Our pooled analysis found that higher age, lower education, lower wealth status, and involvement in any occupations were strongly associated with cigarette smoking (p-value <0.001). However, we did not find a significant association between age and wealth status in Afghanistan, occupations in Nepal and Pakistan, and education in Pakistan with cigarette smoking when country-specific analyses were performed. In this study, socioeconomic position, age, and urban area are strongly associated with cigarette smoking in South Asian countries. The country-specific circumstances should be considered in planning and designing national smoking control strategies and interventions. However, improving access to smoking cessation services could be an effective intervention for all studied countries, Afghanistan, India, Maldives, Nepal, and Pakistan.
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| 5. |
- Rudbäck, Johanna, 1984, et al.
(författare)
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Essential oils can contain allergenic hydroperoxides at eliciting levels, regardless of handling and storage.
- 2015
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Ingår i: Contact dermatitis. - : Wiley. - 1600-0536 .- 0105-1873. ; 73:4, s. 253-4
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Tidskriftsartikel (refereegranskat)abstract
- Essential oils in perfumed products are important skin sensitizers (1). Upon air exposure, lavender oil, with the major components linalool and linalyl acetate, has been shown to produce strongly allergenic hydroper- oxides (2). Furthermore, linalool of natural origin was found to contain a higher concentration of hydroperox- ides than synthesized linalool (3). We have previously studied autoxidation of sweet orange oil (main compound R -limonene)andpetitgrainoil(majorcompoundslinaloo and linalyl acetate) with liquid chromatography/mass spectrometry/mass spectrometry (LC/MS/MS) (4). The investigation was performed at room temperature, under a daylight lamp (12hrs a day), and the oils were stirred 1hr four times a day, according to previous experience (5, 6). In the present study, the importance of handling con- ditions for hydroperoxide formation was investigated. The hydroperoxide concentrations of R -limonene, linalool and linalyl acetate were analysed over time.
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| 6. |
- Singh, Bhupender, et al.
(författare)
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Growth, cell division and sporulation in mycobacteria
- 2010
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Ingår i: Antonie van Leeuwenhoek. International Journal of General and Molecular Microbiology. - : Springer Science and Business Media LLC. - 0003-6072 .- 1572-9699. ; 98:2, s. 165-177
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Tidskriftsartikel (refereegranskat)abstract
- Bacteria have the ability to adapt to different growth conditions and to survive in various environments. They have also the capacity to enter into dormant states and some bacteria form spores when exposed to stresses such as starvation and oxygen deprivation. Sporulation has been demonstrated in a number of different bacteria but Mycobacterium spp. have been considered to be non-sporulating bacteria. We recently provided evidence that Mycobacterium marinum and likely also Mycobacterium bovis bacillus Calmette-Gu,rin can form spores. Mycobacterial spores were detected in old cultures and our findings suggest that sporulation might be an adaptation of lifestyle for mycobacteria under stress. Here we will discuss our current understanding of growth, cell division, and sporulation in mycobacteria.
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