BACKGROUND: Pathogenic treponemes related to Treponema pallidum are both human (causing syphilis, yaws, bejel) and animal pathogens (infections of primates, venereal spirochetosis in rabbits). A set of 11 treponemal genome sequences including those of five Treponema pallidum ssp. pallidum (TPA) strains (Nichols, DAL-1, Mexico A, SS14, Chicago), four T. p. ssp. pertenue (TPE) strains (CDC-2, Gauthier, Samoa D, Fribourg-Blanc), one T. p. ssp. endemicum (TEN) strain (Bosnia A) and one strain (Cuniculi A) of Treponema paraluisleporidarum ecovar Cuniculus (TPeC) were tested for the presence of positively selected genes. METHODOLOGY/PRINCIPAL FINDINGS: A total of 1068 orthologous genes annotated in all 11 genomes were tested for the presence of positively selected genes using both site and branch-site models with CODEML (PAML package). Subsequent analyses with sequences obtained from 62 treponemal draft genomes were used for the identification of positively selected amino acid positions. Synthetic biotinylated peptides were designed to cover positively selected protein regions and these peptides were tested for reactivity with the patient's syphilis sera. Altogether, 22 positively selected genes were identified in the TP genomes and TPA sets of positively selected genes differed from TPE genes. While genetic variability among TPA strains was predominantly present in a number of genetic loci, genetic variability within TPE and TEN strains was distributed more equally along the chromosome. Several syphilitic sera were shown to react with some peptides derived from the protein sequences evolving under positive selection. CONCLUSIONS/SIGNIFICANCE: The syphilis-, yaws-, and bejel-causing strains differed relative to sets of positively selected genes. Most of the positively selected chromosomal loci were identified among the TPA treponemes. The local accumulation of genetic variability suggests that the diversification of TPA strains took place predominantly in a limited number of genomic regions compared to the more dispersed genetic diversity differentiating TPE and TEN strains. The identification of positively selected sites in tpr genes and genes encoding outer membrane proteins suggests their role during infection of human and animal hosts. The driving force for adaptive evolution at these loci thus appears to be the host immune response as supported by observed reactivity of syphilitic sera with some peptides derived from protein sequences showing adaptive evolution.
- MeSH
- bakteriální geny * MeSH
- biologická adaptace * MeSH
- dospělí MeSH
- genomika MeSH
- genotyp * MeSH
- lidé MeSH
- mladý dospělý MeSH
- selekce (genetika) MeSH
- syfilis mikrobiologie patologie MeSH
- Treponema pallidum klasifikace genetika izolace a purifikace MeSH
- Check Tag
- dospělí MeSH
- lidé MeSH
- mladý dospělý MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Clostridium beijerinckii NRRL B-598 is a sporulating, butanol and hydrogen producing strain that utilizes carbohydrates by the acetone-butanol-ethanol (ABE) fermentative pathway. The pathway consists of two metabolic phases, acidogenesis and solventogenesis, from which the latter one can be coupled with sporulation. Thorough transcriptomic profiling during a complete life cycle and both metabolic phases completed with flow cytometry, microscopy and a metabolites analysis helped to find out key genes involved in particular cellular events. The description of genes/operons that are closely involved in metabolism or the cell cycle is a necessary condition for metabolic engineering of the strain and will be valuable for all C. beijerinckii strains and other Clostridial species. The study focused on glucose transport and catabolism, hydrogen formation, metabolic stress response, binary fission, motility/chemotaxis and sporulation, which resulted in the composition of the unique image reflecting clostridial population changes. Surprisingly, the main change in expression of individual genes was coupled with the sporulation start and not with the transition from acidogenic to solventogenic metabolism. As expected, solvents formation started at pH decrease and the accumulation of butyric and acetic acids in the cultivation medium.
- MeSH
- bakteriální proteiny genetika metabolismus MeSH
- Clostridium beijerinckii cytologie genetika MeSH
- fermentace genetika MeSH
- fyziologický stres * genetika MeSH
- glukosa metabolismus MeSH
- kyseliny metabolismus MeSH
- mastné kyseliny metabolismus MeSH
- proteiny tepelného šoku genetika metabolismus MeSH
- regulace genové exprese u bakterií * MeSH
- rozpouštědla metabolismus MeSH
- spory bakteriální metabolismus MeSH
- transkriptom genetika MeSH
- vodík metabolismus MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
BACKGROUND: Thinning supplies of natural resources increase attention to sustainable microbial production of bio-based fuels. The strain Clostridium beijerinckii NRRL B-598 is a relatively well-described butanol producer regarding its genotype and phenotype under various conditions. However, a link between these two levels, lying in the description of the gene regulation mechanisms, is missing for this strain, due to the lack of transcriptomic data. RESULTS: In this paper, we present a transcription profile of the strain over the whole fermentation using an RNA-Seq dataset covering six time-points with the current highest dynamic range among solventogenic clostridia. We investigated the accuracy of the genome sequence and particular genome elements, including pseudogenes and prophages. While some pseudogenes were highly expressed, all three identified prophages remained silent. Furthermore, we identified major changes in the transcriptional activity of genes using differential expression analysis between adjacent time-points. We identified functional groups of these significantly regulated genes and together with fermentation and cultivation kinetics captured using liquid chromatography and flow cytometry, we identified basic changes in the metabolism of the strain during fermentation. Interestingly, C. beijerinckii NRRL B-598 demonstrated different behavior in comparison with the closely related strain C. beijerinckii NCIMB 8052 in the latter phases of cultivation. CONCLUSIONS: We provided a complex analysis of the C. beijerinckii NRRL B-598 fermentation profile using several technologies, including RNA-Seq. We described the changes in the global metabolism of the strain and confirmed the uniqueness of its behavior. The whole experiment demonstrated a good reproducibility. Therefore, we will be able to repeat the experiment under selected conditions in order to investigate particular metabolic changes and signaling pathways suitable for following targeted engineering.
- MeSH
- bakteriofágy genetika MeSH
- butanoly metabolismus MeSH
- Clostridium beijerinckii genetika metabolismus virologie MeSH
- DNA virů genetika MeSH
- fermentace MeSH
- genetická transkripce MeSH
- kinetika MeSH
- pseudogeny genetika MeSH
- sekvenční analýza RNA * MeSH
- stanovení celkové genové exprese * MeSH
- Publikační typ
- časopisecké články MeSH
- MeSH
- bakteriální proteiny genetika metabolismus MeSH
- biofilmy růst a vývoj MeSH
- buněčná membrána účinky léků MeSH
- buněčná stěna účinky léků MeSH
- butanoly metabolismus toxicita MeSH
- Clostridium účinky léků genetika metabolismus MeSH
- fylogeneze MeSH
- genom bakteriální MeSH
- mutageneze MeSH
- průmyslová mikrobiologie metody MeSH
- transkripční faktory genetika metabolismus MeSH
- výpočetní biologie MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- přehledy MeSH
Development of information technologies in recent decades has facilitated also a great progress in the development of new drugs. Methods of Computer-Aided Drug Design allow us to explore the spatial interaction between the receptor and a potential drug. The review deals with a brief summary of these computational methods and is mainly focused on pharmacophore modelling, one of the modern approaches in drug design that has proved to be a useful tool.
