Folia microbiologica最新文献

Colorectal cancer (CRC) has the highest mortality rate among cancer types, emphasizing the need for auxiliaries to 5-fluorouracil (5-FU) due to resistance and side effects. Metabolites produced by probiotic bacteria exhibit promising anticancer properties against CRC. In the current study, the anticancer effects of cell extract of three potential probiotic lactobacilli strains isolated from camel milk, Lactobacillus helveticus, Lactobacillus gallinarum, and Lactiplantibacillus plantarum, as well as that of the standard probiotic strain Lacticaseibacillus rhamnosus GG (LGG), on the human colon cancer cell line (HT-29) and the normal HEK293 cell line separately or in combination with 5-FU, were evaluated. This study isolated strains from camel milk and compared their probiotic properties to those of LGG. The cell viability, cell apoptosis, and Th17 cytokine production were assessed using the MTT assay, acridine orange/ethidium bromide (AO/EB) staining, and flow cytometry techniques, respectively. The cell extracts of lactobacilli strains combined with 5-FU reduced HT-29 cell viability effectively and increased cell apoptosis. Nevertheless, the cell extracts of lactobacilli strains combined with 5-FU controlled the cytotoxic impact of 5-FU on HEK-293 cell viability and reduced cell apoptosis. No significant differences were observed among the strains. Moreover, the cell extracts from the strains combined with 5-FU increased the levels of cytokines IFN-γ, TNF-α, and IL-17A, all of which contribute to immunity against tumors. The performance of the studied strains was similar to that of the standard probiotic strain (LGG). The investigation revealed that cell extracts from lactobacilli strains may serve as a promising complementary anticancer treatment.

Lipids from microorganisms, and especially lipids from Archaea, are used as taxonomic markers. Unfortunately, knowledge is very limited due to the uncultivability of most Archaea, which greatly reduces the importance of the diversity of lipids and their ecological role. One possible solution is to use lipidomic analysis. Six radioactive sources were investigated, two of which are surface (Wettinquelle and Radonka) and four deep from the Svornost mine (Agricola, Behounek, C1, and Curie). A total of 15 core lipids and 82 intact polar lipids were identified from the membranes of microorganisms in six radioactive springs. Using shotgun lipidomics, typical Archaea lipids were identified in spring water, namely dialkyl glycerol tetraethers, archaeol, hydroxyarchaeol and dihydroxyarchaeol. Diverse groups of polar heads were formed in archaeal IPLs, whose polar heads are formed mainly by hexose, deoxyhexose, and phosphoglycerol. The analysis was performed using shotgun lipidomics and the structure of all molecular species was confirmed by tandem mass spectrometry. After acid hydrolysis, a mixture of polar compounds was obtained from the polar head. Further analysis by GC-MS confirmed that the carbohydrates were glucose and rhamnose. Analysis by HPLC-MS of diastereoisomers of 2-(polyhydroxyalkyl)-3-(O-tolylthiocarbamoyl)thiazolidine-4(R)-carboxylates revealed that both L-rhamnose and D-glucose are present in spring samples only in varying amounts. The glycoside composition depends on the type of spring, that is, Wettinquelle and Radonka springs are basically shallow groundwater, while the samples from the Svornost mine are deep groundwater and do not contain glycosides with rhamnose. This method enables quick screening for characteristic Archaea lipids, allowing decisions on whether to pursue further analyses, such as metagenomic analysis, to directly confirm the presence of Archaea.

Brucellosis is a zoonosis with non-specific clinical symptoms involving multiple systems and organs. Its prevalence is low in most of EU countries, which can lead to the difficulties in laboratory and clinical diagnostic. Due to its relationship to the Ochrobactrum spp., it may be misclassified in rapid identification systems. We present a case of a 13-year-old immunocompetent girl who was examined several times for fever, fatigue, night sweats and weight loss; laboratory results showed mildly elevated C-reactive protein, anaemia and leukopenia. Four weeks before the onset of symptoms, she had been on a family holiday in Egypt. Given her symptoms, a haemato-oncological or autoimmune disease was considered more likely. The diagnosis of Brucella spondylitis was made after 4 months. The main reasons for this delay were as follows: low specificity of clinical symptoms, delay in completing the travel history, inconclusive initial serological results and misidentification of the blood culture isolate as Ochrobactrum sp. Even in countries with a low incidence of brucellosis, it is essential to educate healthcare professionals about the disease. Low specificity of symptoms and limited experience of laboratory staff may lead to late diagnosis with risk of complications and poor outcome. If Ochrobactrum spp. is detected in clinical specimens by rapid identification, careful re-evaluation must follow and all measures to prevent laboratory-acquired infections must be taken until Brucella spp. is unequivocally excluded.

Laccases are multi-copper oxidases that play an important role in the biodegradation of phenolic compounds, lignin, dye, and wastes. Here, we report the screening of potential laccase-producing indigenous bacterial isolates and subsequent optimization of laccase production using crop residues as cheap supplementary energy sources. Among 16 bacterial isolates, seven were selected based on the appearance of reddish-brown bacterial colonies and guaiacol oxidation assay after 10 days of incubation at 37 °C. The maximum laccase activity (2.755 U/mL) was observed for bacterial isolate WR2. Response surface methodology (RSM) was used to maximize laccase production from WR2, identified as Pseudomonas stutzeri. Plackett-Burman design (PBD) was employed to design production runs involving various factors including time, pH, inoculum, wheat straw, cotton stalk, wheat bran, rice straw, copper sulfate, sugarcane bagasse, yeast extract, and peptone. The interactions of different factors were analyzed from the responses (laccase enzyme activity, etc.) in 12 experimental runs. In experimental run 4, the maximum laccase enzymatic activity (1.86 U/mL) was achieved after a 10-day incubation with wheat straw (1%) and cotton stalk (1%) at pH 6.8 and 37 °C, and high-degree lignin degradation was evident from a substantial reduction in the FTIR aromatic stretching peak of the degraded biomass.

The genus Armillaria (Basidiomycota, Agaricales, Physalacriaceae) comprises pathogenic fungi that cause root-rot disease in plants, as well as species with low pathogenicity, some of which are hosts of the fully mycoheterotrophic orchid plant Gastrodia elata (Orchidaceae). To investigate the mechanisms underlying such special interactions between Armillaria fungi and G. elata, it is crucial to establish genetic transformation platforms for the Armillaria fungi and G. elata. In this study, an Armillaria strain Arm37 was isolated from G. elata, which can form symbiosis with G. elata in axenic culture under laboratory conditions. A vector pYT-EV containing a cassette for hygromycin-resistance selection and a cassette for expressing or silencing target genes was constructed. An Agrobacterium tumefaciens-mediated transformation (ATMT) system for Arm37 was successfully developed and optimized to achieve a transformation efficiency of 32%. The ATMT system was successfully used to express the reporter genes eGFP encoding enhanced green fluorescent protein and GUS encoding β-glucuronidase and to effectively silence the endogenous gene URA3 encoding orotidine-5'-phosphate decarboxylase in Arm37. This ATMT system established for Arm37 provides an efficient genetic tool for exploring the Arm37 genes that are involved in the unique interaction between the Armillaria fungi and fully mycoheterotrophic plant G. elata.

The aim of this study is to evaluate opportunistic pathogenic bacteria of the genus Pseudomonas in anthropogenically impacted bathing waters, primarily focusing on bathing ponds. The findings include the detection of these bacteria, their susceptibility to selected antibiotics, and the determination of the Exotoxin A (exoA) gene using PCR method. P. aeruginosa was present in most samples, albeit in low concentrations (1-14 CFU/100 mL). The presence of P. otitidis, which is associated with ear infection, in this type of bathing water, was not rare (up to 90 CFU/100 mL). This species would not be detected by the standard methods, including tests on acetamid medium, used for P. aeruginosa in water. The isolated strains of P. otitidis lack the exoA gene and exhibited higher resistance to meropenem compared to P. aeruginosa.

Previous studies have predominantly focused on the pathogenic mechanisms and epidemiological investigations of pathogenic Escherichia coli (E. coli), but much remains unknown about the non-virulent and non-drug-resistant E. coli (NVNR E. coli) residing in the pig gut. In this study, 215 E. coli strains were identified from fecal samples collected from 26 healthy pigs in Guangdong Province, China. Among them, 12 NVNR E. coli strains were identified through PCR, antibiotic susceptibility tests, and genomic virulence analysis. Phylogenetic analysis revealed that 8 of these NVNR E. coli strains were located in the upstream cluster of the phylogenetic tree, which we consider as the ancestral phylogroup of porcine native E. coli. Notably, strain 2-9 showed a close evolutionary relationship with the probiotics Nissle1917 and EcAZ-1, suggesting it may also be a probiotic strain. These 9 strains (i.e., the 8 ancestral phylogroup strains and the suspected probiotic strain) were designated as evolutionarily superior strains. The 12 NVNR E. coli strains were non-hemolytic and exhibited growth rates comparable to typical E. coli strains, but they varied significantly in their tolerance to gastrointestinal conditions and adherence to IPEC-J2 cells. Most of them lacked the ability to inhibit pathogenic E. coli. Interestingly, the majority of strains exhibiting strong gastrointestinal tolerance, most of those with high adhesion capacity, and all strains possessing antibacterial ability, were found within the range of 9 evolutionarily superior strains. These findings suggest that 9 strains have shown great potential as superior porcine native E. coli strains and warrant further study.

The physicochemistry, metabolic properties, and microbial community structure of a tropical estuary persistently inundated with anthropogenic pollutants were elucidated using diverse analytical tools and a shotgun metagenomics approach. The physicochemistry of the Awoye estuary surface water (AEW) and sediment (AES) revealed higher values in the sediment for most of the parameters analyzed, while aside from copper and zinc, the concentrations of the detected heavy metals (Cd, Cr, Pb, Fe, As, Ni, Hg, Mn, Se) in the water and sediment were higher than the acceptable thresholds. Hydrocarbon content analysis revealed increasingly high concentrations of high molecular weight polycyclic aromatic hydrocarbons (HMW PAHs) in the sediment. Structurally, the predominant taxa in the AEW metagenome are Proteobacteria (50.35%), Alphaproteobacteria (43.31%), Brevundimonas (49.96%), and Leptolyngbya boryana (14.93%), while in the sediment (AES) metagenome, Proteobacteria (53.03%), Gammaproteobacteria (28.66%), Azospirillum (6.51%), and Acidihalobacter prosperus (7.56%) were preponderant. Statistical analysis of the two microbiomes (AEW, AES) revealed significant statistical differences (P < 0.05) at all the hierarchical levels. Functional characterization of the two metagenomes revealed extensive adaptations of the sediment microbiome to various environmental stressors as evident in the high numbers of putative genes involved in the degradation of diverse classes of aromatic hydrocarbons, efflux, detoxification, and transport of heavy metals, and metabolism of organic/inorganic nutrients. Findings from this study revealed that the estuary sediment is the sink for most of the anthropogenic pollutants and harbors the more adapted microbiome that could serve as a potential bioresource for the bioremediation of the perturbed estuary.

Recurrent acute otitis media (rAOM) poses a significant challenge in children aged 1 to 6 years, characterized by frequent and treatment-resistant ear infections. While existing studies predominantly focus on alterations in the nasopharyngeal microbiome associated with rAOM, our research explores the understudied association with the gut microbiome. In this cross-sectional observational prospective study, we enrolled 35 children aged 1 to 6 years during the 2021/2022 cold season. The test group comprised children with rAOM (n = 16), and the control group consisted of generally healthy children (n = 19). Samples (stool and nasopharyngeal swabs) were collected in late spring to ensure an antibiotic-free period. Detailed metadata was gathered through a questionnaire examining factors potentially influencing microbiota. Microbiota composition was assessed through amplicon sequencing of the V3-V4 region of the 16S rRNA gene. Our findings revealed limited alterations in gut microbiota composition among children with rAOM compared to healthy controls. Six bacterial taxa (Veillonella, Lachnospiraceae, Ruminococcaceae, Lachnospiraceae, Bacteroides and Blautia) were differentially represented with weak statistical significance. However, several bacterial taxa displayed correlations with multiple consecutive infections, with Turicibacter showing the most significant association. Additionally, day care centre attendance emerged as a potent gut microbiota modifier, independent of rAOM. Although our study identified limited differences in gut microbiota composition between children with rAOM and healthy controls, the observed correlations between the number of infections and specific bacterial taxa suggest a potential link between rAOM and the gut microbiota, warranting further investigation.