Polyhydroxyalkanoates are microbial polyesters which are considered being biological alternatives to petrochemical polymers. Extremophiles, such as thermophilic PHA producers, hold promise to improve competitiveness of PHA production process. Therefore, this work aimed at isolation of new strains, which could produce PHA under elevated temperature. Since traditional Nile red staining of colonies provided false positive results in thermophiles, we developed a novel strategy of enriching microbial consortia by PHA producers. This so called "osmoselective strategy" is based on application of osmotic challenge by sudden exposition of the mixed microbial culture to hypertonic and subsequently to hypotonic conditions; moreover, this strategy relies on the fact that PHA protect bacteria from negative effects of rapid fluctuations in osmotic pressure. In combination with fast and reliable ATR-FTIR inspection of selected colonies for presence of PHA, we were able to isolate several promising thermophilic or thermotolerant PHA producing strains belonging to the genera Bacillus, Aneurinibacillus and Chelatococcus, which indeed deserves further investigation to evaluate their potential for industrial production of PHA.
- MeSH
- Alphaproteobacteria izolace a purifikace MeSH
- Bacillales izolace a purifikace MeSH
- Bacillus izolace a purifikace MeSH
- Bacteria izolace a purifikace MeSH
- bioreaktory MeSH
- DNA bakterií MeSH
- fermentace MeSH
- mikrobiální společenstva * MeSH
- osmóza MeSH
- polyhydroxyalkanoáty chemie MeSH
- sekvence nukleotidů MeSH
- termotolerance MeSH
- vysoká teplota MeSH
- Publikační typ
- časopisecké články MeSH
In the context of ongoing climate change, expected temperature rise may significantly limit plant growth and productivity of crop species. In this study, we investigated the effects of a sub-optimal temperature on buckwheat, a pseudocereal known for its nutraceutical advantages. Two buckwheat species differing by their reproduction method, namely Fagopyrum esculentum and Fagopyrum tataricum were grown at 21 °C and 27 °C in growth chambers. High temperature increased leaf production mainly in F. tataricum but decreased leaf area in both species. Water and photosynthesis-related parameters were affected by high temperature but our results suggested that although transpiration rate was increased, adaptive mechanisms were developed to limit the negative impact on photosynthesis. High temperature mainly affected the reproductive stage. It delayed flowering time but boosted inflorescence and flower production. Nevertheless, flower and seed abortions were observed in both species at 27 °C. Regarding flower fertility, heat affected more the female stage than the male stage and reduced the stigma receptivity. Pollen production increased with temperature in F. esculentum while it decreased in F. tataricum. Such discrepancy could be related to the self-incompatibility of F. esculentum. Both species increased their antioxidant production under high temperature to limit oxidative stress and antioxidant capacity was higher in the inflorescences than in the leaves. Total flavonoid content was particularly increased in the leaves of F. esculentum and in the inflorescences of F. tataricum. Altogether, our results showed that even if high temperature may negatively affect reproduction in buckwheat, it improves its antioxidant content.
A thermotolerant bacterial strain 1D isolated from refinery oil-contaminated soil was identified as Gordonia sp. based on the analysis of 16S rRNA and gyrB gene sequences. The strain was found to utilize crude oil, diesel fuel, and a wide spectrum of alkanes at temperatures up to 50 °C. Strain 1D is the first representative of Gordonia amicalis capable of utilizing alkanes of chain length up to С36 at a temperature of 45-50 °C. The degree of crude oil degradation by Gordonia sp. 1D at 45 °C was 38% in liquid medium and 40% in soil (with regard to abiotic loss). There are no examples of so effective hydrocarbon-oxidizing thermotolerant Gordonia in the world literature. The 1D genome analysis revealed the presence of two alkane hydroxylase gene clusters, genes of dibenzothiophene cleavage, and the cleavage of salicylate and gentisate - naphthalene metabolism intermediates. The highly efficient thermotolerant strain Gordonia sp. 1D can be used in remediation of oil-contaminated soils in hot climates.
- MeSH
- bakteriální geny MeSH
- biodegradace MeSH
- fylogeneze MeSH
- genom bakteriální genetika MeSH
- Gordonia bacterium klasifikace genetika metabolismus fyziologie MeSH
- multigenová rodina MeSH
- půdní mikrobiologie MeSH
- RNA ribozomální 16S genetika MeSH
- ropa metabolismus MeSH
- sekvenční analýza DNA MeSH
- substrátová specifita MeSH
- termotolerance * MeSH
- Publikační typ
- časopisecké články MeSH
Targeting mutations to specific genomic loci is invaluable for assessing in vivo the effect of these changes on the biological role of the gene in study. Here, we attempted to introduce a mutation that was previously implicated in an increased heat stability of the mesophilic cyanobacterium Synechocystis sp. PCC6803 via homologous recombination to the psbA gene of Chlamydomonas reinhardtii. For that, we established a strategy for targeted mutagenesis that was derived from the efficient genome-wide homologous-recombination-based methodology that was used to target individual genes of Saccharomyces cerevisiae. While the isolated mutants did not show any benefit under elevated temperature conditions, the new strategy proved to be efficient for C. reinhardtii even in the absence of direct positive selection.
- MeSH
- Chlamydomonas reinhardtii genetika MeSH
- fotosystém II (proteinový komplex) genetika MeSH
- geneticky modifikované rostliny genetika MeSH
- genom plastidový genetika MeSH
- homologní rekombinace MeSH
- mutageneze cílená metody MeSH
- rostlinné proteiny genetika MeSH
- selekce (genetika) MeSH
- serin genetika MeSH
- substituce aminokyselin MeSH
- Synechocystis genetika MeSH
- termotolerance genetika MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Cytokinins are phytohormones that are involved in many processes in plants, including growth, differentiation and leaf senescence. However, they also have various activities in animals. For example, kinetin and trans-zeatin can reduce levels of several aging markers in human fibroblasts. Kinetin can also protect mice against oxidative and glyoxidative stress, and prolong fruit flies' lifespan. Additionally, several cytokinins are currently used in cosmetics. To extend knowledge of the breadth of cytokinins' activities, we examined effects of natural cytokinin bases on the model nematode Caenorhabditis elegans. We found that kinetin, para-topolin and meta-topolin prolonged the lifespan of C. elegans. Kinetin also protected the organism against oxidative and heat stress. Furthermore, our results suggest that presence of reactive oxygen species, but not DAF-16 (the main effector of the insulin/insulin-like growth factor signaling pathway), is required for the beneficial effects of kinetin. Ultra-high performance liquid chromatography-tandem mass spectrometric analysis showed that kinetin is unlikely to occur naturally in C. elegans, but the worm efficiently absorbs and metabolizes it into kinetin riboside and kinetin riboside-5'-monophosphate.
- MeSH
- Caenorhabditis elegans účinky léků genetika fyziologie MeSH
- cytokininy farmakokinetika farmakologie MeSH
- dlouhověkost účinky léků fyziologie MeSH
- forkhead transkripční faktory genetika metabolismus MeSH
- inzulin metabolismus MeSH
- kinetin farmakokinetika farmakologie MeSH
- mutace MeSH
- oxidační stres účinky léků MeSH
- proteiny Caenorhabditis elegans genetika metabolismus MeSH
- reakce na tepelný šok účinky léků MeSH
- reaktivní formy kyslíku metabolismus MeSH
- regulátory růstu rostlin farmakokinetika farmakologie MeSH
- signální transdukce účinky léků MeSH
- termotolerance účinky léků MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Research Support, N.I.H., Extramural MeSH
Bacterial metabolites with communicative functions could provide protection against stress conditions to members of the same species. Yet, information remains limited about protection provided by metabolites in Bacillus cereus and inter-species. This study investigated the effect of extracellular compounds derived from heat shocked (HS) and non-HS cultures of B. cereus and Geobacillus stearothermophilus on the thermotolerance of non-HS vegetative and sporulating B. cereus. Cultures of B. cereus and G. stearothermophilus were subjected to HS (42 or 65 °C respectively for 30 min) or non-HS treatments. Cells and supernatants were separated, mixed in a combined array, and then exposed to 50 °C for 60 min and viable cells determined. For spores, D values (85 and 95 °C) were evaluated after 120 h. In most cases, supernatants from HS B. cereus cultures added to non-HS B. cereus cells caused their thermotolerance to increase (D 50 12.2-51.9) when compared to supernatants from non-HS cultures (D 50 7.4-21.7). While the addition of supernatants from HS and non-HS G. stearothermophilus cultures caused the thermotolerance of non-HS cells from B. cereus to decrease initially (D 50 3.7-7.1), a subsequent increase was detected in most cases (D 50 18-97.7). In most cases, supernatants from sporulating G. stearothermophilus added to sporulating cells of B. cereus caused the thermotolerance of B. cereus 4810 spores to decline, whereas that of B. cereus 14579 increased. This study clearly shows that metabolites in supernatants from either the same or different species (such as G. stearothermophilus) influence the thermotolerance of B. cereus.
- MeSH
- Bacillus cereus účinky léků metabolismus fyziologie účinky záření MeSH
- Geobacillus stearothermophilus metabolismus fyziologie účinky záření MeSH
- mikrobiální interakce * MeSH
- mikrobiální viabilita účinky léků účinky záření MeSH
- spory bakteriální účinky léků fyziologie účinky záření MeSH
- teplota MeSH
- termotolerance účinky léků MeSH
- vysoká teplota MeSH
- Publikační typ
- časopisecké články MeSH
- MeSH
- antibakteriální látky MeSH
- bakteriální léková rezistence MeSH
- Campylobacter izolace a purifikace patogenita MeSH
- červené maso mikrobiologie MeSH
- drůbež mikrobiologie MeSH
- kampylobakterové infekce * epidemiologie přenos MeSH
- lidé MeSH
- nemoci přenášené potravou * epidemiologie mikrobiologie MeSH
- termotolerance MeSH
- virulence MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- práce podpořená grantem MeSH
- Geografické názvy
- Česká republika MeSH
- MeSH
- metabolismus MeSH
- termotolerance MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- MeSH
- poporodní období MeSH
- termoregulace MeSH
- termotolerance MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
