دكتوراه
الطب والخدمات الصحية
The University of Sheffield
| مجال التميز | التميز الدراسي والبحثي |
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البحوث المنشورة |
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| البحث (1): | |
| عنوان البحث: | Analysis of Kytococcus sedentarius Strain Isolated from a Dehumidifier Operating in a University Lecture Theatre: Systems for Aerobic Respiration, Resisting Osmotic Stress, and Sensing Nitric Oxide |
| رابط إلى البحث: | https://www.karger.com/Article/Pdf/512751 |
| تاريخ النشر: | 17/03/2021 |
| موجز عن البحث: | A strain of Kytococcus sedentarius was isolated from a dehumidifier operating in a university lecture theatre. Genome analysis and phenotypic characterisation showed that this strain, K. sedentarius MBB13, was a moderately halotolerant aerobe with a branched aerobic electron transport chain and genes that could contribute to erythromycin resistance. The major compatible solute was glycine betaine, with ectoine and proline being deployed at higher osmolarities. Actinobacteria possess multiple WhiB-like (Wbl) regulatory proteins, and K. sedentarius MBB13 has four (WhiB1, WhiB2, WhiB3, and WhiB7). Wbls are iron-sulfur proteins that regulate gene expression through interactions with RNA polymerase sigma factors and/or other regulatory proteins. Bacterial two-hybrid analyses suggested that WhiB1 and WhiB2, but not WhiB3 and WhiB7, interact with the C-terminal domain of the major sigma factor, σA; no interaction was detected between any of the Wbl proteins and the only alternative sigma factors, σB, σH, or σJ . The interaction between σA and WhiB1 or WhiB2 was disrupted in a heterologous system under growth conditions that produce nitric oxide and the iron-sulfur clusters of the isolated WhiB1 and WhiB2 proteins reacted with nitric oxide. Thus, K. sedentarius strain exhibits the major phenotypic characteristics of the type strain and a comprehensive examination of the interactions between its four Wbl proteins and four sigma factors suggested that the Wbl proteins all operate through interaction with σA. |
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المؤتمرات العلمية |
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| المؤتمر (1): | |
| عنوان المؤتمر: | Journal of Cell Science & Therapy |
| تاريخ الإنعقاد: | 21/03/2019 |
| مكان الإنعقاد: | Italy |
| طبيعة المشاركة: | Paper Presentation |
| عنوان المشاركة: |
Structure-function properties of Kytococcus sedentarius WhiB1
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| ملخص المشاركة: | Kytococcus sedentarius (Ks) is an opportunistic bacterium involved in pitted keratolysis, cerebral cyst infections, endocarditis and bacteraemia. WhiB-like (Wbl) proteins are a family of proteins that are only located in actinomycetes and play important role in developmental processes. The C-terminal regions are rich in positively charged amino acids, suggesting a role in DNA-binding. The N-terminal regions possess four conserved cysteine residues that act as anchors for iron-sulfur clusters, which respond to redox stress. This study shows that: (i) the cluster can be isolated in three forms, (ii) the cluster is important to structure the protein and, (iii) the cluster is sensitive to spermine nitric oxide (NO) but not oxygen (O2). The significance is the iron-sulfur cluster of WhiB1 is a key factor in the protein function. The cluster modulates the conformation of the protein, changes the DNA-binding properties and allows the protein to respond to NO but not O2. These facts suggest that WhiB1 has a role as an NO- responsive gene regulator that could be important for survival and persistence in human macrophages. |
