Microorganisms最新文献

This study aimed to determine the presence of relevant infectious and parasitic agents (IPAs) in managed honeybees from Central Italy and the Republic of Kosovo and Albania to assess the overall health status of local apiaries by determining the contamination levels and co-occurrence. Therefore, pathogens and parasites such as Paenibacillus larvae, Melissococcus plutonius, Vairimorpha apis, V. ceranae, the acute bee paralysis virus (ABPV), black queen cell virus (BQCV), chronic bee paralysis virus (CBPV), deformed wing virus variants DWV-A and DWV-B, and the parasitoid flies Megaselia scalaris and Senotainia tricuspis were detected by quantitative polymerase chain reaction (qPCR) and reverse transcriptase qPCR (RT-qPCR) in clinically healthy adult honeybees collected from 187 apiaries in the Abruzzo and Molise regions of Central Italy, 206 apiaries in the Republic of Kosovo in 2022 and 2023 and 18 apiaries in Albania in 2022. The percentages of positive samples and contamination for V. ceranae, P. larvae and DWV-B were significantly higher in the Republic of Kosovo and Albania, while the percentages of samples positive for M. plutonius, CBPV, DWV-A, and the parasitoid flies were higher in Central Italy. Additionally, P. larvae and some viruses showed significantly different occurrence rates between the two years in Italy and the Republic of Kosovo. The co-occurrence of IPAs also differed between the two geographic areas. Their varying distribution could depend on epidemiological dynamics, climatic factors, and management practices specific to each country, whose relative impact should be defined to guide targeted interventions to reduce honeybee mortality.

The study of coronaviruses has undergone unprecedented acceleration over recent years, driven largely by the global impact of SARS-CoV-2 and growing recognition of the extraordinary diversity and zoonotic potential of coronaviruses across species [...].

We report the first synthesis of IspH-directed prodrugs targeting the terminal enzyme of the 2-C-methyl-D-erythritol 4-phosphate (MEP) pathway, (E)-4-hydroxy-3-methylbut-2-enyl diphosphate reductase (IspH or LytB). A series of alkyne and pyridine monophosphate cycloSaligenyl (cycloSal) prodrugs were prepared to enhance membrane permeability by masking the phosphate group. The effects of electron-withdrawing (Cl, CF₃) and electron-donating (OCH₃, NH₂) substituents were examined, together with amino acid-functionalized and mutual prodrug analogs. Among the synthesized compounds, chlorine-substituted derivatives 5c and 6c displayed the strongest antimycobacterial activity against Mycobacterium smegmatis, surpassing isoniazid in agar diffusion assays. These results indicate that electron-withdrawing substituents accelerate prodrug hydrolysis and facilitate intracellular release of the active inhibitor. This work provides the first experimental evidence of an IspH-targeted prodrug approach, highlighting the cycloSal strategy as a valuable tool for delivering phosphorylated inhibitors and developing novel antimycobacterial agents acting through the MEP pathway.

Electroactive biofilms (EABs) are essential for the performance of bioelectrochemical systems (BESs), but their formation in Geobacter, critically on conductive pili and exopolysaccharides, limits application under conditions where these components are deficient. Herein, we investigated the restorative effects of exogenous flavin mononucleotide (FMN) on EAB formation and extracellular electron transfer (EET) in two defective mutants of Geobacter sulfurreducens: the pili-deficient PCAΔ1496 and exopolysaccharides-deficient PCAΔ1501. Results show that FMN significantly promoted biofilm thickness in PCAΔ1496 (250%) and PCAΔ1501 (33%), while boosting maximum current outputs by 175-fold and 317.7%, respectively. Spectroscopic and electrochemical analyses revealed that FMN incorporates into biofilms, binds to outer membrane c-type cytochromes (c-Cyts), and enhances electron exchange capacity. Differential pulse voltammetry further confirmed that FMN did not exist independently in the biofilm but bound to outer membrane c-Cyts as a cofactor. Collectively, exogenous FMN plays dual roles (electron shuttle and cytochrome-bound cofactor) in defective Geobacter EABs, effectively restoring biofilm formation and enhancing EET efficiency. This study expands the understanding of the formation mechanism of Geobacter EABs and provides a novel strategy for optimizing BES performance.

Burkholderia pseudomallei complex and B. cepacia complex are two evolutionary distinct clades of pathogens causing human disease. Most vaccine efforts have focused on the former group largely due to their biothreat status and global disease burden. It has been proposed that a vaccine could be developed that simultaneously protects against both groups of Burkholderia by specifically targeting conserved antigens. Only a few studies have set out to identify which antigens may be optimal targets for such a vaccine. We have previously assessed the ability of three highly conserved B. pseudomallei antigens, namely OmpA1, OmpA2, and Pal, coupled to gold nanoparticle vaccines, to protect mice against a homotypic B. pseudomallei challenge. Here, we have expanded our study by demonstrating that antibodies to each of these proteins show varying levels of reactivity to homologues in B. cepacia complex, with OmpA2 antibodies exhibiting the highest cross-reactivity. Remarkably, some nanovaccine immunized mice, particularly those that received OmpA2, produced antibodies that bind Pseudomonas aeruginosa, which harbors distantly related homologous proteins. T cells elicited to Pal and OmpA2 responded to stimulation with B. cepacia complex-derived homologues. Our study supports incorporation of these antigens, particularly OmpA2, for the development of a pan-Burkholderia vaccine.

Forest type strongly influences soil microbial community composition and associated carbon cycling, yet its influence on microbial functional traits remains poorly understood. In this study, metagenomics sequencing was used to investigate soil microbial communities and carbon metabolism genes across three forest types: deciduous broadleaf (DBF), mixed coniferous-broadleaf (CBMF), and coniferous forest (CF) at two soil depths (0-20 cm and 20-40 cm) on Lushan Mountain in subtropical China. The results showed that CF exhibited higher bacterial diversity and a distinct microbial composition, with an increase in Actinomycetota and Bacteroidota and a decrease in Acidobacteriota and Pseudomonadota. The Calvin cycle was the dominant carbon fixation pathway in all forests, while the relative abundance of secondary pathways (i.e., the 3-hydroxypropionate bi-cycle and reductive citrate cycle) varied significantly with forest type. Key carbon fixation genes (sucD, pckA) were more abundant in CF and CBMF, with higher levels of rpiA/B and ackA in DBF. Functional profiling further indicated that CF soils, especially in the surface layer, were enriched in glycoside hydrolases (GHs) and carbohydrate esterases (CEs), while CBMF showed a greater potential for starch and lignin degradation. Multivariate statistical analyses identified soil available phosphorus (AP) and pH as primary factors shaping microbial community variation, with AP emerging as being the dominant regulator of carbon-related functional gene abundance. Overall, the prevalence of these distinct genetic potentials across forest types underscores how vegetation composition may shape microbial functional traits, thereby influencing the stability and dynamics of the soil carbon pool in forest ecosystem.

Bee-derived products such as apitoxin, royal jelly, propolis, bee pollen, and honey are increasingly being used as part of cosmetic products because all of them contain a large number of bioactive compounds with antioxidant, anti-inflammatory, antimicrobial, and regenerative properties, which enable them to be used for therapeutic purposes. The aim of this investigation was to assess the performance of an automated growth-based system in order to make a quantitative examination of the total aerobic viable counts in bee-derived personal care products using NF-TVC vials that contained a nutrient-based medium with dextrose as the carbon source. According to USP general chapter <1223>, pivotal validation criteria such as linearity, equivalence of results, operative range, precision, accuracy, ruggedness, limit of quantification, and limit of detection have demonstrated that the automated system can be used for a reliable total aerobic viable count. Moreover, the actual research demonstrated that polysorbates efficiently block the antimicrobiological potential of bioactive compounds, such as phenols, flavonoids, enzymes, peptides, and fatty acids, which naturally occur in apitoxin, royal jelly, propolis, bee pollen, and honey, allowing for efficient microorganism recovery from the bee-made products tested. Therefore, this AGBS could be applied efficiently within the cosmetic industry to assess the total aerobic viable count in bee-derived products such as capillary treatments, toothpaste, and anti-aging cream, affording several benefits associated with faster product release into the market.

Dientamoeba fragilis is a protozoan of the human digestive tract, yet its transmission and pathogenic role remain poorly understood. This study aimed to evaluate its impact on the efficacy and safety of fecal microbiota transplantation (FMT) in treating recurrent Clostridioides difficile infection (rCDI). This longitudinal cohort study analyzed stool samples from FMT donors and recipients pre-treatment and at 2 and 8 weeks post-FMT. All samples were retrospectively tested using real-time PCR. Shotgun metagenomics was also performed on selected donor-recipient pairs to explore transmission. CDI cure rates, gastrointestinal adverse events (AEs), and serious adverse events (SAEs) were assessed prospectively. A total of 53 FMT were analyzed (179 samples), with 23 (43%) derived from D. fragilis-positive donor stool (4 of 10 donors, 40%). Four of 52 recipients (18.2%), initially negative and who received treatment from positive donors, tested positive post-FMT. Shotgun metagenomics could not definitely confirm transmission due to the lack of a good reference genome. No significant differences in efficacy, AE, or SAE were observed between FMT from D. fragilis-positive versus -negative donors, even in immunocompromised patients. No SAEs were attributed to FMT. D. fragilis may be transmitted via FMT without evidence of short-term clinical impact. Consequently, RT-PCR detection should be interpreted cautiously in the context of donor exclusion decisions.

Biofilm formation represents a key survival strategy employed by Vibrio cholerae to adapt to the complex intestinal environment of the host. While most previous studies on V. cholerae biofilms have focused on genetic regulation and monospecies cultures, its ability to form dual-species biofilms with other intestinal pathogens is still poorly understood. In this study, using samples from both cholera patients and healthy individuals, Fusobacterium nucleatum was identified as a bacterium capable of co-aggregating with V. cholerae. Untargeted metabolomic analysis revealed that F. nucleatum-derived metabolites, specifically 6-hypoxanthine, enhance biofilm formation in V. cholerae. Further validation confirmed that these F. nucleatum-derived metabolites upregulate the biofilm-associated regulatory gene vpsT. In an adult mouse model, co-infection with F. nucleatum and V. cholerae significantly enhanced the intestinal adaptability of V. cholerae compared to infection with V. cholerae alone. Together, these findings elucidate the mechanism enabling the co-infection of F. nucleatum and V. cholerae in the host intestine, thereby shedding new light on how other pathogenic bacteria can assist in V. cholerae infection.

Gastric cancer (GC) is the fifth most common cancer worldwide, with the highest incidence in East Asia. Although H. pylori is a well-known risk factor, carcinogenesis can occur independently of H. pylori infection, and approximately 43% of adults carry H. pylori as part of their native microbiota. This study aimed to identify potential oral and gastric microbial markers across different histological stages of GC in both H. pylori-positive and -negative patients. Buccal swabs and gastric mucosa samples were collected from patients with intestinal metaplasia, low-grade dysplasia, high-grade dysplasia, early GC, or advanced GC. Total DNA was extracted, and 16S rRNA gene amplicon sequencing was performed. Microbiome diversity generally remained stable across histological stages, with no directional shifts in community structure. Differential abundance analysis revealed higher relative abundances of Anaerostipes, Phocaeicola, and Collinsella in the gastric antrum of cancerous samples. Anaerostipes and Phocaeicola are typically enriched in the intestinal microbiota but are rarely observed in the stomach, suggesting their potential ecological and pathological relevance in gastric carcinogenesis. In H. pylori-negative patients, however, a different stage-associated abundance pattern was observed, in which Faecalibacterium, a genus predominantly associated with the intestinal environment, was less abundant in advanced gastric cancer samples than in earlier histological stages within the gastric body. These findings suggest that microbial changes during gastric cancer progression may follow different trajectories depending on H. pylori infection status. In oral samples, Haemophilus and Prevotella were more abundant in intestinal metaplasia than in low-grade dysplasia, and network analysis indicated links between Neisseria and Filifactor at oral and gastric sites. However, as the study population was limited to a single country and ethnicity, the applicability of these microbial markers should be carefully considered.