The recent revision of the Acidithiobacillia class using genomic taxonomy methods has shown that, in addition to the existence of previously unrecognized genera and species, some species of the class harbor levels of divergence that are congruent with ongoing differentiation processes. In this study, we have performed a subspecies-level analysis of sequenced strains of Acidithiobacillus ferrooxidans to prove the existence of distinct sublineages and identify the discriminant genomic/genetic characteristics linked to these sublineages, and to shed light on the processes driving such differentiation. Differences in the genomic relatedness metrics, levels of synteny, gene content, and both integrated and episomal mobile genetic elements (MGE) repertoires support the existence of two subspecies-level taxa within A. ferrooxidans. While sublineage 2A harbors a small plasmid related to pTF5, this episomal MGE is absent in sublineage 2B strains. Likewise, clear differences in the occurrence, coverage and conservation of integrated MGEs are apparent between sublineages. Differential MGE-associated gene cargo pertained to the functional categories of energy metabolism, ion transport, cell surface modification, and defense mechanisms. Inferred functional differences have the potential to impact long-term adaptive processes and may underpin the basis of the subspecies-level differentiation uncovered within A. ferrooxidans. Genome resequencing of iron- and sulfur-adapted cultures of a selected 2A sublineage strain (CCM 4253) showed that both episomal and large integrated MGEs are conserved over twenty generations in either growth condition. In turn, active insertion sequences profoundly impact short-term adaptive processes. The ISAfe1 element was found to be highly active in sublineage 2A strain CCM 4253. Phenotypic mutations caused by the transposition of ISAfe1 into the pstC2 encoding phosphate-transport system permease protein were detected in sulfur-adapted cultures and shown to impair growth on ferrous iron upon the switch of electron donor. The phenotypic manifestation of the △pstC2 mutation, such as a loss of the ability to oxidize ferrous iron, is likely related to the inability of the mutant to secure the phosphorous availability for electron transport-linked phosphorylation coupled to iron oxidation. Depletion of the transpositional △pstC2 mutation occurred concomitantly with a shortening of the iron-oxidation lag phase at later transfers on a ferrous iron-containing medium. Therefore, the pstII operon appears to play an essential role in A. ferrooxidans when cells oxidize ferrous iron. Results highlight the influence of insertion sequences and both integrated and episomal mobile genetic elements in the short- and long-term adaptive processes of A. ferrooxidans strains under changing growth conditions.
- Klíčová slova
- sirné bakterie, acidofilní bakterie, anaerobní prostředí, pyrit,
- MeSH
- Acidithiobacillus * chemie metabolismus MeSH
- adsorpce MeSH
- Bacteria chemie metabolismus MeSH
- biochemické jevy * MeSH
- biotechnologie MeSH
- kationty chemie MeSH
- oxidace-redukce MeSH
- proteom MeSH
- síra chemie MeSH
- těžební a zpracovatelský průmysl metody MeSH
- železo chemie MeSH
Colicin production in Escherichia coli (E. coli) strains represents an important trait with regard to microbial survival and competition in the complex intestinal environment. A novel colicin type, colicin Z (26.3 kDa), was described as a product of an original producer, extraintestinal E. coli B1356 strain, isolated from the anorectal abscess of a 17 years-old man. The 4,007 bp plasmid (pColZ) was completely sequenced and colicin Z activity (cza) and colicin Z immunity (czi) genes were identified. The cza and czi genes are transcribed in opposite directions and encode for 237 and 151 amino acid-long proteins, respectively. Colicin Z shows a narrow inhibitory spectrum, being active only against enteroinvasive E. coli (EIEC) and Shigella strains via CjrC receptor recognition and CjrB- and ExbB-, ExbD-mediated colicin translocation. All tested EIEC and Shigella strains isolated between the years 1958-2010 were sensitive to colicin Z. The lethal effect of colicin Z was found to be directed against cell wall peptidoglycan (PG) resulting in PG degradation, as revealed by experiments with Remazol Brilliant Blue-stained purified peptidoglycans and with MALDI-TOF MS analyses of treated PG. Colicin Z represents a new class of colicins that is structurally and functionally distinct from previously studied colicin types.
- MeSH
- Escherichia coli genetika MeSH
- koliciny genetika MeSH
- lidé MeSH
- mikrobiální testy citlivosti MeSH
- mladiství MeSH
- plazmidy genetika MeSH
- sekvence nukleotidů MeSH
- Shigella genetika MeSH
- Check Tag
- lidé MeSH
- mladiství MeSH
- mužské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
490 stran : ilustrace ; 25 cm
Humorný román z prostředí vojenských lékařů.
- MeSH
- vojenské lékařství MeSH
- Publikační typ
- beletrie MeSH
- Konspekt
- Česká próza
- NLK Obory
- humanitní vědy a umění
Geodiversity plays an important role in species establishment during spontaneous succession. At post-mining sites in the Czech Republic in 2003, we established plots in which the surface of the heaped overburden was either kept wave-like or leveled. Based on surveys conducted from 2006 to 2015, leveled plots were increasingly dominated by grasses and herbs (and especially by the grass Calamagrostis epigejos) while the wave-like plots were increasingly dominated by the trees Salix caprea and Betula pendula. In 2015, a detailed survey was conducted of the dominant species. Both S. caprea and B. pendula occurred more often in wave-like plots than in leveled plots; this was particularly true for trees taller than 1 m, which were absent in leveled plots. In wave-like plots, leaf and root biomasses of both woody species were higher on the wave slopes than on the wave depressions. Nitrogen content was higher but content stress indicating proline in leaves of S. caprea was lower in wave-like plots than in leveled plots. In wave-like plots, both woody species occurred mainly on wave slopes but C. epigejos occurred mainly in the depressions. We speculate that trees were more abundant in wave-like plots than in leveled plots because the waves trapped tree seeds and snow and because the soil porosity was greater in wave-like than in leveled plots. Grasses may have preferred the leveled plots because soil porosity was lower and clay content was higher in leveled than in wave-like plots.
- MeSH
- dřevo MeSH
- lipnicovité * MeSH
- půda MeSH
- stromy MeSH
- životní prostředí * MeSH
- Publikační typ
- časopisecké články MeSH
- Geografické názvy
- Česká republika MeSH
In extremely acidic environments, ferric iron can be a thermodynamically favorable electron acceptor during elemental sulfur oxidation by some Acidithiobacillus spp. under anoxic conditions. Quantitative 2D-PAGE proteomic analysis of a resting cell suspension of a sulfur-grown Acidithiobacillus ferrooxidans CCM 4253 subculture that had lost its iron-reducing activity revealed 147 protein spots that were downregulated relative to an iron-reducing resting cell suspension of the antecedent sulfur-oxidizing culture and 111 that were upregulated. Tandem mass spectrometric analysis of strongly downregulated spots identified several physiologically important proteins that apparently play roles in ferrous iron oxidation, including the outer membrane cytochrome Cyc2 and rusticyanin. Other strongly repressed proteins were associated with sulfur metabolism, including heterodisulfide reductase, thiosulfate:quinone oxidoreductase and sulfide:quinone reductase. Transcript-level analyses revealed additional downregulation of other respiratory genes. Components of the iron-oxidizing system thus apparently play central roles in anaerobic sulfur oxidation coupled with ferric iron reduction in the studied microbial strain.
- MeSH
- 2D gelová elektroforéza MeSH
- Acidithiobacillus chemie genetika metabolismus MeSH
- anaerobióza MeSH
- bakteriální proteiny analýza MeSH
- mutace MeSH
- oxidace-redukce MeSH
- proteom analýza MeSH
- síra metabolismus MeSH
- stanovení celkové genové exprese MeSH
- tandemová hmotnostní spektrometrie MeSH
- železo metabolismus MeSH
- Publikační typ
- časopisecké články MeSH
- srovnávací studie MeSH
To clarify the pathway of anaerobic sulfur oxidation coupled with dissimilatory ferric iron reduction in Acidithiobacillus ferrooxidans strain CCM 4253 cells, we monitored their energy metabolism gene transcript profiles. Several genes encoding electron transporters involved in aerobic iron and sulfur respiration were induced during anaerobic growth of ferrous iron-grown cells. Most sulfur metabolism genes were either expressed at the basal level or their expression declined. However, transcript levels of genes assumed to be responsible for processing of elemental sulfur and other sulfur intermediates were elevated at the beginning of the growth period. In contrast, genes with predicted functions in formation of hydrogen sulfide and sulfate were significantly repressed. The main proposed mechanism involves: outer membrane protein Cyc2 (assumed to function as a terminal ferric iron reductase); periplasmic electron shuttle rusticyanin; c4-type cytochrome CycA1; the inner membrane cytochrome bc1 complex I; and the quinone pool providing connection to the sulfur metabolism machinery, consisting of heterodisulfide reductase, thiosulfate:quinone oxidoreductase and tetrathionate hydrolase. However, an alternative mechanism seems to involve a high potential iron-sulfur protein Hip, c4-type cytochrome CycA2 and inner membrane cytochrome bc1 complex II. Our results conflict with findings regarding the type strain, indicating strain- or phenotype-dependent pathway variation.
U pacientů s Parkinsonovou nemocí (PN) je ve stadiu pozdních hybných a psychických komplikací dosažení dlouhodobě vyrovnaného stavu velmi obtížné. V tomto stadiu lze terapeuticky použít buď hlubokou mozkovou stimulaci (s výjimkou pacientů s kognitivními poruchami nebo s demencí) nebo intestinální infuzní podání levodopy spolu s carbidopou (Duodopa®), výjimečně subkutánní podávání apomorfinu. Je prezentován případ 63letého muže s pokročilou PN ve stadiu pozdních motorických a psychických komplikací, u kterého byla po selhání klasické farmakoterapie použita dlouhodobě a bezpečně terapie Duodopou®.
It is very difficult to achieve long‑term balance in the clinical status of patients with Parkinson's disease (PD) suffering from late motor and mental complications. As for therapy at this stage, deep brain stimulation (not suitable for patients with cognitive deficits or dementia) or intestinal infusion of levodopa plus carbidopa (Duodopa®) can be used; subcutaneous application of apomorphine can be implemented exceptionally. We present the case of 63‑year‑old man with advanced PD suffering from late motor and mental complications in whom Duodopa® treatment has been safely used for a long time after the failure of classical pharmacotherapy.
- MeSH
- antiparkinsonika terapeutické užití MeSH
- karbidopa terapeutické užití MeSH
- levodopa * aplikace a dávkování terapeutické užití MeSH
- lidé středního věku MeSH
- lidé MeSH
- parenterální infuze MeSH
- Parkinsonova nemoc * farmakoterapie MeSH
- Check Tag
- lidé středního věku MeSH
- lidé MeSH
- mužské pohlaví MeSH
- Publikační typ
- kazuistiky MeSH
In contrast to iron-oxidizing Acidithiobacillus ferrooxidans, A. ferrooxidans from a stationary phase elemental sulfur-oxidizing culture exhibited a lag phase in pyrite oxidation, which is similar to its behaviour during ferrous iron oxidation. The ability of elemental sulfur-oxidizing A. ferrooxidans to immediately oxidize ferrous iron or pyrite without a lag phase was only observed in bacteria obtained from growing cultures with elemental sulfur. However, these cultures that shifted to ferrous iron oxidation showed a low rate of ferrous iron oxidation while no growth was observed. Two-dimensional gel electrophoresis was used for a quantitative proteomic analysis of the adaptation process when bacteria were switched from elemental sulfur to ferrous iron. A comparison of total cell lysates revealed 39 proteins whose increase or decrease in abundance was related to this phenotypic switching. However, only a few proteins were closely related to iron and sulfur metabolism. Reverse-transcription quantitative PCR was used to further characterize the bacterial adaptation process. The expression profiles of selected genes primarily involved in the ferrous iron oxidation indicated that phenotypic switching is a complex process that includes the activation of genes encoding a membrane protein, maturation proteins, electron transport proteins and their regulators.
- MeSH
- 2D gelová elektroforéza MeSH
- Acidithiobacillus růst a vývoj metabolismus fyziologie MeSH
- bakteriální proteiny biosyntéza MeSH
- fyziologická adaptace MeSH
- genetická transkripce MeSH
- kvantitativní polymerázová řetězová reakce MeSH
- metabolické sítě a dráhy genetika MeSH
- oxidace-redukce MeSH
- polymerázová řetězová reakce s reverzní transkripcí MeSH
- proteom analýza MeSH
- regulace genové exprese * MeSH
- síra metabolismus MeSH
- stanovení celkové genové exprese MeSH
- sulfidy metabolismus MeSH
- železnaté sloučeniny metabolismus MeSH
- železo metabolismus MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
The conventional stoichiometry of the oxidation of elemental sulfur by ferric iron in Acidithiobacillus ferrooxidans was not in agreement with our experimental data in terms of ferrous iron and proton formation. Reaction modelling under the actual conditions of bacterial activity resulted in a different stoichiometry, where additional iron species participate in the process to affect the number of released protons. The suggested reaction equation may more accurately predict the intensity of environmental acidification during the anaerobic bioprocess.
- MeSH
- Acidithiobacillus metabolismus MeSH
- anaerobióza MeSH
- energetický metabolismus MeSH
- oxidace-redukce MeSH
- síra metabolismus MeSH
- železité sloučeniny metabolismus MeSH
- železnaté sloučeniny metabolismus MeSH
- železo metabolismus MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
