Radon springs, characterized by their high concentrations of radon gas (Rn222), are extreme environments with unique physicochemical conditions distinct from conventional aquatic ecosystems. Our ...research aimed to investigate microbial life in radon springs, focusing on isolating extremophilic bacteria and assessing their resistance to adverse conditions. Our study revealed the prevalence of Actinomycetia species in the radon spring environment. We conducted various tests to evaluate the resistance of these isolates to oxidative stress, irradiation, desiccation, and metal ion content. These extremophilic bacteria showed overall higher resistance to these stresses compared to control strains. Lipidomic analysis was also employed to provide insights into the adaptive mechanisms of these bacteria which were found mainly in the correlations among individual clusters and changes in content of fatty acids (FA) as well as differences between content and type of FAs of environmental isolates and type strains.
Fungal contamination poses a persistent challenge to industries, particularly in food, healthcare, and clinical sectors, due to the remarkable resilience of fungi in withstanding conventional control ...methods. In this context, our research delves into the comparative efficacy of UV radiation and non-thermal plasma (NTP) on key foodborne fungal contaminants -
,
,
, and
. The study examined the impact of varying doses of UV radiation on the asexual spores of all mentioned fungal strains. Simultaneously, the study compared the effects of UV radiation and NTP on the metabolic activity of cells after spore germination and their subsequent germination ability. The results revealed that UV-C radiation (254 nm) did not significantly suppress the metabolic activity of cells after spore germination. In contrast, NTP exhibited almost 100% effectiveness on both selected spores and their subsequent germination, except for
. In the case of
, the effectiveness of UV-C and NTP was nearly comparable, showing only a 35% decrease in metabolic activity after 48 hours of germination, while the other strains (
,
,
) exhibited a reduction of more than 95%. SEM images illustrate the morphological changes in structure of all tested spores after both treatments. This study addresses a crucial gap in existing literature, offering insights into the adaptation possibilities of treated cells and emphasizing the importance of considering exposure duration and nutrient conditions (introduction of fresh medium). The results highlighted the promising antimicrobial potential of NTP, especially for filamentous fungi, paving the way for enhanced sanitation processes with diverse applications.
Metal nanoparticle synthesis via environmentally friendly methods is gaining interest for their potential advantages over conventional physico-chemical approaches. Herein, we propose a robust green ...synthesis route for lignin-modified silver nanoparticles, utilizing the recovery of lignin as a renewable raw material and exploring its application in valuable areas. Through a systematic approach combining UV-Vis spectroscopy with AAS and DLS, we identified repeatable and scalable reaction conditions in an aqueous solution at pH 11 for homogeneous silver nanoparticles with high uniformity. The TEM median sizes ranged from 12 to 15 nm with circularity between 0.985 and 0.993. The silver nanoparticles yield exceeded 0.010 mol L
, comparable with traditional physico-chemical methods, with a minimal loss of silver precursor ranging between 0.5 and 3.9%. Characterization by XRD and XPS revealed the presence of Ag-O bonding involving lignin functional groups on the pure face-centered cubic structure of metallic silver. Moreover, the lignin-modified silver nanoparticles generated a localized thermal effect upon near-infrared laser irradiation (808 nm), potentially allowing for targeted applications in the biomedical field. Our study showcases the potential of lignin as a renewable reducing and capping agent for silver nanoparticle synthesis, addressing some shortcomings of green synthesis approaches and contributing to the development of suitable nanomaterials.
•Four genera of thermophilic bacteria were analyzed.•Using off-line two-dimensional LC-tandem MS menaquinones (MK5) to MK15 were found.•A mixture of menaquinones having cis/trans double bond(s) was ...separated.
Thermophilic bacteria of four genera in contrast to the commonly used production strains such as Bacillus subtilis, produce homologs other than menaquinone (MK) with seven isoprene units. The number of isoprene units and the configuration of double bonds are essential factors for their biological activity. The goal was to obtain a strain of bacteria that produces a wide range of MK homologs and only all-trans geometrical isomers, which was the strain G. kaustophilus. Using off-line two-dimensional LC–tandem MS in columns with the RP18 phase and the COSMOSIL cholester phase (separation according to the geometric configuration of double bonds) it was shown that thermophilic bacteria grown at different temperatures produce only all-trans isomers of menaquinones from MK-5 (menaquinone with five isoprenyl units) to MK-15 (fifteen isoprenyl units). Therefore, G. kaustophilus appears to be a biotechnologically important strain produces only trans isomers and additionally homologs from 5 to 15 isoprene units.
Microscopic filamentous fungi are ubiquitous microorganisms that adapt very easily to a variety of environmental conditions. Due to this adaptability, they can colonize a number of various surfaces ...where they are able to start forming biofilms. Life in the form of biofilms provides them with many benefits (increased resistance to desiccation, UV radiation, antimicrobial compounds, and host immune response). The aim of this study is to find a reliable and reproducible methodology to determine biofilm growth of selected microscopic filamentous fungi strains. Several methods (crystal violet staining, MTT assay, XTT assay, resazurin assay) for the determination of total biofilm biomass and its metabolic activity were tested on four fungi – Alternaria alternata, Aspergillus niger, Fusarium culmorum and Fusarium graminearum, and their biofilm was also imaged by spinning disc confocal microscopy using fluorescent dyes. A reproducible biofilm quantification method is essential for the subsequent testing of the biofilm growth suppression using antifungal agents or physical methods. Crystal violet staining was found to be a suitable method for the determination of total biofilm biomass of selected strains, and the MTT assay for the determination of metabolic activity of the biofilms. Calcofluor white and Nile red fluorescent stains successfully dyed the hyphae of microscopic fungi.
•Fungal biofilms could cause severe problems in food industry.•For successful removal of biofilms, proper characterization of their growth is needed.•One of the first studies dealing with fungal biofilm growth characterization.•Crystal violet staining is suitable for total fungal biofilm biomass determination.•MTT assay is suitable for fungal biofilm metabolic activity determination.
Two minor phospholipids, i.e., mono- and/or dimethylphosphatidylethanolamines, are widespread in many organisms, from bacteria to higher plants and animals. A molecular mixture of methyl-PE and ...dimethyl-PE was obtained from total lipids by liquid chromatography and further identified by mass spectrometry. Total methyl-PE and dimethyl-PE were cleaved by phospholipase C, and the resulting diacylglycerols, in the form of acetyl derivatives, were separated into alkyl-acyl, alkenyl-acyl, and diacylglycerols. Reversed-phase LC/MS allowed dozens of molecular species to be identified and further analyzed. This was performed on a chiral column, and identification by tandem positive ESI revealed that diacyl derivatives from all four bacteria were mixtures of both R and S enantiomers. The same applied to alkenyl-acyl derivatives of anaerobic bacteria. Analysis thus confirmed that some bacteria biosynthesize phospholipids having both sn-glycerol-3-phosphate and sn-glycerol-1-phosphate as precursors. These findings were further supported by data already published in GenBank. The use of chiral chromatography made it possible to prove that both enantiomers of glycerol phosphate of some molecular species of mono- and dimethylphosphatidylethanolamines are present. The result of the analysis can be interpreted that the cultured bacteria do not have homochiral membranes but, on the contrary, have an asymmetric, i.e., heterochiral membranes.
This paper represents the results of screening a diversity of fungal endophytes associated with
Vitis vinifera
leaves and canes in the Czech Republic. The characterization of strains is based on ...morphological and phylogenetic analyses of ITS, EF1α and TUB2 sequence data. Our strain selection covers 16 species and seven orders belonging to Ascomycota and Basidiomycota. Together with ubiquitous fungi, we report on several poorly known plant-associated fungi,
Angustimassarina quercicola
(=
A. coryli
, a synonym proposed in this study) and
Pleurophoma pleurospora
. Other species, such as
Didymella negriana
,
D. variabilis
,
Neosetophoma
sp. (species identical or sister to
N. rosae
),
Phragmocamarosporium qujingensis
and
Sporocadus rosigena
, have so far been little known and rarely found, but are frequent on
V. vinifera
in different parts of the world and obviously belong to a microbiota with a strong preference for this plant. Detailed taxonomical identification allowed us to identify species with apparent stable associations with
V. vinifera
, for which further interactions with
V. vinifera
can be expected. Our study is the first to focus on
V. vinifera
endophytes in Central Europe and expands the knowledge about their taxonomy, ecology and geography.
The increasing risk of antibiotic failure in the treatment of
Pseudomonas aeruginosa
infections is largely related to the production of a wide range of virulence factors. The use of non-thermal ...plasma (NTP) is a promising alternative to antimicrobial treatment. Nevertheless, there is still a lack of knowledge about the effects of NTP on the virulence factors production. We evaluated the ability of four NTP-affected
P. aeruginosa
strains to re-form biofilm and produce Las-B elastase, proteases, lipases, haemolysins, gelatinase or pyocyanin. Highly strains-dependent inhibitory activity of NTP against extracellular virulence factors production was observed. Las-B elastase activity was reduced up to 82% after 15-min NTP treatment, protease activity and pyocyanin production by biofilm cells was completely inhibited after 60 min, in contrast to lipases and gelatinase production, which remained unchanged. However, for all strains tested, a notable reduction in biofilm re-development ability was depicted using spinning disc confocal microscopy. In addition, NTP exposure of mature biofilms caused disruption of biofilm cells and their dispersion into the environment, as shown by transmission electron microscopy. This appears to be a key step that could help overcome the high resistance of
P. aeruginosa
and its eventual elimination, for example in combination with antibiotics still highly effective against planktonic cells.
This study investigates the effect of pure yeast culture fermentation versus spontaneous fermentation on the volatile compound profile of industrially produced plum brandy. Using traditional ...distillation methods, the evolution of key volatile compounds is monitored at seven different moments during the distillation process. By integrating advanced analytical techniques such as GC-MS and sensory evaluation, significant differences in the composition of the distillates are highlighted, particularly in terms of ethyl esters and higher alcohols which are key to the sensory properties of the final product. Distillates produced with the addition of pure cultures gave higher concentrations of esters than those obtained by wild fermentation. The results of our industrial research show that the most critical step is to limit the storage of the input raw material, thereby reducing the subsequent risk of producing higher concentrations of 1-propanol. Furthermore, our results indicate that the heart of the distillate can only be removed up to an ethanol content of approximately 450 g/L and that the removal of additional ethanol results in only a 10% increase in the total volume of the distillate, which in turn results in an increase in boiler heating costs of approximately 30%.
