There are two main types of bacterial photosynthesis: oxygenic (cyanobacteria) and anoxygenic (sulfur and non-sulfur phototrophs). Molecular mechanisms of photosynthesis in the phototrophic microorganisms can differ and depend on their location and pigments in the cells. This paper describes bacteria capable of molecular oxidizing hydrogen sulfide, specifically the families Chromatiaceae and Chlorobiaceae, also known as purple and green sulfur bacteria in the process of anoxygenic photosynthesis. Further, it analyzes certain important physiological processes, especially those which are characteristic for these bacterial families. Primarily, the molecular metabolism of sulfur, which oxidizes hydrogen sulfide to elementary molecular sulfur, as well as photosynthetic processes taking place inside of cells are presented. Particular attention is paid to the description of the molecular structure of the photosynthetic apparatus in these two families of phototrophs. Moreover, some of their molecular biotechnological perspectives are discussed.
- Klíčová slova
- anaerobes, anoxygenic bacteria, detoxification, hydrogen sulfide, molecular mechanisms of photosynthesis, water environment,
- MeSH
- anaerobióza MeSH
- Chlorobi klasifikace genetika fyziologie MeSH
- Chromatiaceae klasifikace genetika fyziologie MeSH
- fototrofní procesy genetika MeSH
- fylogeneze MeSH
- síra metabolismus MeSH
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
- Názvy látek
- síra MeSH
While mechanisms of different carbon dioxide (CO2 ) assimilation pathways in chemolithoautotrohic prokaryotes are well understood for many isolates under laboratory conditions, the ecological significance of diverse CO2 fixation strategies in the environment is mostly unexplored. Six stratified freshwater lakes were chosen to study the distribution and diversity of the Calvin-Benson-Bassham (CBB) cycle, the reductive tricarboxylic acid (rTCA) cycle, and the recently discovered archaeal 3-hydroxypropionate/4-hydroxybutyrate (HP/HB) pathway. Eleven primer sets were used to amplify and sequence genes coding for selected key enzymes in the three pathways. Whereas the CBB pathway with different forms of RubisCO (IA, IC and II) was ubiquitous and related to diverse bacterial taxa, encompassing a wide range of potential physiologies, the rTCA cycle in Epsilonproteobacteria and Chloribi was exclusively detected in anoxic water layers. Nitrifiying Nitrosospira and Thaumarchaeota, using the rTCA and HP/HB cycle respectively, are important residents in the aphotic and (micro-)oxic zone of deep lakes. Both taxa were of minor importance in surface waters and in smaller lakes characterized by an anoxic hypolimnion. Overall, this study provides a first insight on how different CO2 fixation strategies and chemical gradients in lakes are associated to the distribution of chemoautotrophic prokaryotes with different functional traits.
- MeSH
- Archaea metabolismus MeSH
- chemoautotrofní růst fyziologie MeSH
- Chlorobi genetika metabolismus MeSH
- citrátový cyklus fyziologie MeSH
- Epsilonproteobacteria genetika metabolismus MeSH
- fotosyntéza fyziologie MeSH
- hydroxybutyráty metabolismus MeSH
- jezera chemie mikrobiologie MeSH
- koloběh uhlíku fyziologie MeSH
- kyselina mléčná analogy a deriváty metabolismus MeSH
- oxid uhličitý metabolismus MeSH
- ribulosa-1,5-bisfosfát-karboxylasa genetika metabolismus MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- 4-hydroxybutyric acid MeSH Prohlížeč
- hydracrylic acid MeSH Prohlížeč
- hydroxybutyráty MeSH
- kyselina mléčná MeSH
- oxid uhličitý MeSH
- ribulosa-1,5-bisfosfát-karboxylasa MeSH
