Search Results (120)

In this study, for the first time, the genes encoding the mammalian steroidogenesis system—cytochrome P450scc (CYP11A1), and its native redox partners adrenodoxin and adrenodoxin reductase—were successfully expressed in the methylobacterium Methylorubrum extorquens. The advantage of using methylobacteria as an expression chassis is that they grow on inexpensive mineral media, use methanol as a carbon and energy source, and do not possess their own sterol catabolism systems. Using recombinant methylobacteria, the valuable steroid pregnenolone was obtained as a sole metabolite from cholesterol. The effect of media composition, bioconversion conditions such as methanol and N-sources content, modes of substrate addition, detergents, methyl-β-cyclodextrin, biomass, and aeration on pregnenolone accumulation was investigated. Under optimized conditions, its yield exceeded 100 mg/L. The results demonstrate a proof of concept relating to the use of bacteria lacking their own steroid degradation systems as microbial chassis for heterologous steroidogenesis systems, including mammalian cytochrome CYP11A1. Full article

(1) Background: Methylobacterium radiotolerans (M. radiotolerans) is a fastidious, aerobic, Gram-negative bacillus primarily found in environmental sources such as soil and sewage, with rare clinical isolation. Its identification remains challenging due to poor growth with conventional culture methods. (2) Case presentation: A 42-year-old male patient with early T-cell precursor acute lymphoblastic leukemia (ETP-ALL) presented with M. radiotolerans bacteremia during hospitalization. The organism was successfully isolated from peripheral blood using the Myco/F Lytic culture vial (Becton, Dickinson and Company, Lincoln, MT, USA). Comparative analysis demonstrated markedly superior growth of M. radiotolerans in Myco/F Lytic culture vials compared with Plus Aerobic/F Lytic and Lytic/10 Anaerobic/F culture vials (Becton, Dickinson and Company, Lincoln, MT, USA). Antimicrobial susceptibility testing, performed with the epsilometer test (E-test) and Bauer–Kirby disk diffusion (BK) method, guided the selection of an appropriate therapeutic regimen. The patient’s infection was ultimately controlled following targeted antimicrobial therapy. (3) Conclusions: M. radiotolerans demonstrates a distinct growth preference for the Myco/F Lytic culture medium. This observation highlights the importance of considering alternative culture media in cases of rare or fastidious bacterial infections that cannot be reliably detected using conventional Plus Aerobic/F Lytic or Lytic/10 Anaerobic/F culture vials, which are typically employed for clinical isolation of aerobic and anaerobic bacteria. Full article

As an important complementation of plant genetic traits, seed endophytes (SEs) have garnered significant attention due to their crucial roles in plant germination and early seedling establishment. In this study, we employed both culture-dependent and amplicon sequencing-based approaches to characterize the endophytic microbiome in seed samples derived from different individual Panax notoginseng plants. Additionally, we evaluated the antagonistic activity of isolated culturable bacterial SEs against the root rot pathogens Fusarium solani and F. oxysporum. Our results demonstrated that a greater sampling quantity substantially increased the species richness (Observed OTUs) and diversity of seed endophytic microbiota, underscoring the importance of seed population size in facilitating the vertical transmission of diverse endophytes to progeny. The endophytic communities (including both fungi and bacteria) exhibited a conserved core microbiota alongside host-specific rare taxa, forming a phylogenetically and functionally diverse endophytic resource pool. Core bacterial genera included Streptococcus, Methylobacterium-Methylorubrum, Sphingomonas, Burkholderia-Caballeronia-Paraburkholderia, Pantoea, Halomonas, Acinetobacter, Pseudomonas, Vibrio, and Luteibacter, while core fungal genera comprised Davidiella, Thermomyces, Botryotinia, Myrothecium, Haematonectria, and Chaetomium. Among 256 isolated endophytic bacterial strains, 11 exhibited strong inhibitory effects on the mycelial growth of F. solani and F. oxysporum. Further evaluation revealed that two antagonistic strains, Bacillus cereus and B. toyonensis, significantly enhanced seed germination and plant growth in P. notoginseng, and effectively suppressed root rot disease in seedlings. These findings highlight the potential use of SEs as biocontrol agents and growth promoters in sustainable agriculture. Full article

Microbial symbioses play crucial roles in insect physiology, contributing to nutrition, detoxification, and metabolic adaptations. However, the microbial communities associated with the lac insect Llaveia axin axin, an economically significant species used in traditional lacquer production, remain poorly characterized. In this study, the bacterial diversity and community structure of L. axin axin were investigated using both culture-dependent and culture-independent (metagenomic) approaches, combined with fatty acid profile analysis. The insects were bred at the laboratory level, in controlled conditions, encompassing stages from eggs to adult females. Bacterial strains were isolated from bacteriomes and identified through 16S rRNA gene amplification and genomic fingerprinting through ARDRA analysis. Metagenomic DNA was sequenced using the Illumina MiSeq platform, and fatty acid profiles were determined by gas chromatography–mass spectrometry (GC-MS). A total of 20 bacterial strains were isolated, with Acinetobacter, Moraxella, Pseudomonas, and Staphylococcus detected in first-instar nymphs; Methylobacterium, Microbacterium, and Bacillus in pre-adult females; and Bacillus and Microbacterium in adults. Metagenomic analysis revealed key genera including Sodalis, Blattabacterium, and Candidatus Walczuchella, with Sodalis being predominant in early stages and Blattabacteriaceae in adults. Fatty acid analysis identified palmitic, oleic, linoleic, arachidic, and stearic acids, with stearic acid being the most abundant. These results suggest that dominant bacteria contribute to lipid biosynthesis and metabolic development in L. axin axin. Full article

A wide range of microorganisms, including endophytes, frequently interact with forest trees. The role of endophytes in industrial conifers has not been fully investigated. The Yezo spruce Picea jezoensis is widely used for logging in Russia and Japan. In this work, the endophytic communities of bacteria and fungi in healthy needles, branches, and fresh wood of P. jezoensis from Primorsky Territory were analyzed using metagenomic analysis. The results indicate that the diversity of endophytic communities in P. jezoensis is predominantly influenced by the specific tree parts (for both bacteria and fungi) and by different tree specimens (for fungi). The most abundant bacterial classes were Alphaproteobacteria, Gammaproteobacteria and Actinobacteria. Functional analysis of KEGG orthologs (KOs) in endophytic bacterial community using PICRUSt2 and the PLaBAse PGPT ontology revealed that 59.5% of the 8653 KOs were associated with plant growth-promoting traits (PGPTs), mainly, colonization, stress protection, bio-fertilization, bio-remediation, vitamin production, and competition. Metagenomic analysis identified a high abundance of the genera Pseudomonas and Methylobacterium-Methylorubrum in P. jezoensis, which are known for their potential growth-promoting activity in other coniferous species. The dominant fungal classes in P. jezoensis were Dothideomycetes, Sordariomycetes, and Eurotiomycetes. Notably, the genus Penicillium showed a pronounced increase in relative abundance within the fresh wood and needles of Yezo spruce, while Aspergillus displayed elevated abundance specifically in the fresh wood. It is known that some of these fungi exhibit antagonistic activity against phytopathogenic fungi. Thus, our study describes endophytic communities of the Yezo spruce and provides a basis for the production of biologicals with potential applications in forestry and agriculture. Full article

As a sessile wax scale insect, Ericerus pela heavily relies on its host plant for nutrition. While E. pela utilizes the nitrogen-poor plant sap as its primary nutrient source, the mechanisms by which this insect overcomes the nitrogen deficiency are poorly understood. In this study, we first confirm the nitrogen fixation capability of E. pela through isotopic tracer experiments and the acetylene reduction assay, which demonstrate that female adults exhibit an efficient nitrogen fixation rate. High-throughput sequencing further revealed 42 nitrogen-fixing bacterial species in the tissues of E. pela, most notably including Rhizobiales and Methylobacterium as the dominant species converting atmospheric nitrogen to ammonia. Several critical genes involved in nitrogen fixation, ammonia transporting, amino acid synthesis, and transportation were determined to be transcriptionally active across different developmental stages of E. pela. In addition, the symbiotic fungus Ophiocordyceps—located in the fat body of E. pela—was found to be capable of synthesizing all amino acids, including the essential amino acids required for the survival of E. pela. Taken together, this study demonstrates that E. pela has evolved a highly effective nitrogen acquisition system driven by symbiotic microorganisms, ensuring a sufficient nitrogen supply and enabling it to thrive on nitrogen-deficient food sources. Our findings reveal a unique evolutionary adaptation in which E. pela leveraged both bacterial nitrogen fixation and fungal amino acid synthesis to bolster its growth and development. Full article

Actinomycosis is an uncommon but significant chronic bacterial infection affecting various parts of the body caused by Actinomyces species. Because of the nonspecific symptoms and rarity of the condition, the diagnosis of head-and-neck or cervicofacial actinomycosis is usually challenging and delayed. A 39-year-old woman presented with an enlarging right neck mass and dysphagia after steroid exposure for treatment of De Quervain thyroiditis. MRI showed a large irregular infiltration mass over the right side of her neck, with a multi-loculated rim-enhancing area over the right retropharyngeal space. Excisional biopsy of the lesion only showed evidence of acute on chronic inflammation, and the results of all microbiological testing (including bacterial culture, Gram-staining, and molecular detection) were negative. Metagenomic next-generation sequencing (mNGS) of the formalin-fixed paraffin-embedded (FFPE) tissue from the patient was performed. DNA of Actinomyces israelii and Methylobacterium was detected. The patient was confirmed to have cervical actinomycosis and completely recovered after 6 months of oral amoxicillin. Our patient is the first case utilizing mNGS on FFPE tissue to diagnose cervical actinomycosis. This case shows that mNGS is a promising, unbiased tool for detecting Actinomyces species in FFPE tissues and diagnosing cervical actinomycosis. It also highlights the diagnostic difficulties of cervical actinomycosis. Full article

Endophytic bacteria inhabit plant tissues without damaging them and have specialized adaptation capabilities that allow them to establish themselves in this ecological niche. Endophytes produce numerous secondary metabolites with antimicrobial, anticancer, and pesticide properties, among others. In this study, endophytic bacteria were isolated and characterized from cocoa plants in a Brazilian municipality, with the view to evaluate their potential antagonistic activity on clinical bacterial strains. The isolates were identified through phenotypic analysis and molecular characterization. After bacterial isolation, it was possible to verify the presence of 11 different endophytic strains, with a bacterial load of up to 6.3 × 10³ CFU/g in each plant. The morphological and biochemical profile of the isolates varied. At the taxonomic level, these bacteria showed 99% similarity with the genera Microbacterium, Curtobacterium, Pseudomonas, Bacillus, Ralstonia, and Methylobacterium. The strains of the phylum Actinobacteria, which are known for producing natural bioactive compounds with high biotechnological potential, were effective in inhibiting Staphylococcus aureus ATCC and multidrug-resistant clinical strains. This work aims to expand knowledge about endophytes, with the aim of applying them in other sectors, such as the production of compounds against resistant human pathogens. Full article

The development of efficient bioinoculant formulations requires compounds with stabilizing, thickening, and carrier functions to preserve microbial viability and promote biological activity in soil. However, the majority of studies evaluate inoculant formulations predominantly in terms of bacterial viability, overlooking other important performance parameters. This study employed an integrative approach combining in vitro and plant-based assays to assess the effects of starch, carboxymethyl cellulose (CMC), and trehalose in formulations containing Azospirillum brasilense, Bradyrhizobium diazoefficiens, Methylobacterium symbioticum, and Paenibacillus alvei, applied to Glycine max seeds. Our hypothesis was that the presence of these additives, each with distinct functional roles (starch as a slow-release carbon source, CMC as a structural agent and protector against physical stress, and trehalose as an osmoprotectant and membrane stabilizer), would influence not only bacterial viability but also the seed germination, growth, and physiological responses of inoculated G. max plants. Starch improved viability in A. brasilense formulations, while both starch and trehalose had positive effects on M. symbioticum. These additives also enhanced plant traits, including dry biomass, chlorophyll content, carboxylation efficiency (A/Ci), and photochemical efficiency (Fv/Fm and Pi_Abs). Trehalose was particularly effective in formulations with B. diazoefficiens and M. symbioticum, supporting its use as a versatile stabilizer. In contrast, CMC (0.25%) negatively impacted bacterial viability, especially for B. diazoefficiens and P. alvei, and impaired physiological parameters in G. max when combined with M. symbioticum. These results highlight the need to evaluate formulation components not only for their physical roles but also for their specific interactions with microbial strains and effects on host plants. Such an integrative approach is essential for designing stable, efficient bioinoculants that align with sustainable agricultural practices. Full article

The plant microbiome plays a crucial role in the health of the tea plant, while Bacillus thuringiensis (Bt) is widely utilized as a biological pesticide in tea gardens, promoting sustainable agricultural practices. However, the effects of Bt spraying on tea quality and the structure and function of the phyllosphere microbiome remain unclear. This study evaluated the effects of Bt spraying on tea quality, microbiome composition, diversity, and potential functions using tea leaf quality measurements and high-throughput sequencing of the 16S/ITS rDNA genes. Results showed that spraying Bt1 significantly increased the contents of free amino acids (by 15.27%), flavonoids (by 18.00%), soluble sugars (by 62.55%), and key compounds such as epicatechin gallate (by 10.50%), gallocatechin gallate (by 122.52%), and epigallocatechin gallate (by 61.29%), leading to improved leaf quality. Co-occurrence network analysis indicated that the community structure of both epiphytic and endophytic microbes became more complex after Bt treatment. The abundance of beneficial bacteria, such as Novosphingobium, Methylobacterium, and Sphingomonas, increased significantly, while pathogenic fungi like Aspergillus and Phyllosticta decreased. Functional prediction indicated enhanced amino acid metabolism, secondary metabolism, and carbohydrate metabolism, particularly the biosynthesis of flavonoids, which supports disease resistance and boosts secondary metabolite levels. Furthermore, Bt application reduced pathogenic fungi, enhancing the tea plant’s resistance to diseases. Overall, foliar spraying of Bt can positively alter the phyllosphere microbiome by enriching beneficial bacteria and improving metabolic functions, ultimately enhancing tea plant resistance and quality, and providing a scientific basis for sustainable pest management in tea cultivation. Full article

Faba bean is a high-protein legume that can be successfully grown in most climates around the world. It is one of the most popular pulses cultivated in Poland. Its seeds are a source of plant protein, used most often in feed production. Field experiments and laboratory seed analyses were carried out in 2022 and 2023 to assess the effect of the application of nitrogen-fixing bacteria on the yield and seed quality of a low-tannin faba bean cultivar. The factor was tested at four levels: control, seed inoculation with Rhizobium leguminosarum bv. viceae, foliar spraying with Methylobacterium symbioticum, and seed inoculation and spraying (double application). The application of N-fixing bacteria had a positive effect on faba bean seed yield. In 2022, plants responded most effectively to a double application, increasing seed yield by 25.4%, while, in 2023, the highest seed yield was obtained after inoculation (12.3% increase). Although the single application of bacteria caused a decrease in seed protein content, the double application (inoculation and spraying) significantly enhanced seed protein content. The protein productivity per hectare was compensated by the higher seed yield and increased by 41.7% in 2022 and 14.9% in 2023 compared to plots where N-fixing bacteria were not applied. This work shows that it is possible to use different strains of N-fixing bacteria in faba bean cultivation and this can significantly improve yields while reducing the need for synthetic nitrogen fertilizers, which supports sustainable production. Full article

Maize is considered to be one of the most significant crops in the world. On a global scale, the appropriate yield level of food can largely affect food security. During cultivation, this plant is exposed to many adverse environmental factors, including water deficiency. Plant stress is reduced by applying appropriate biostimulants or soil amendments. This study tested the effectiveness of preparations based on Rhizophagus irregularis, humic acids, Bacillus velezensis + Bacillus licheniformis and Methylobacterium symbioticum. The aim of the project was to assess the effect of selected microorganisms and substances on the growth, yield, and physiological parameters of maize. The hypothesis assumed that the preparations selected for this study could improve the condition of the plants in various soil moisture conditions. All treatments were carried out post-emergence. The experiments were conducted in greenhouse conditions, where, in conditions of different level of soil moisture, optimal and water deficiency, the effect of the above-mentioned substances and microorganisms on the height, mass of plants, and plant chlorophyll fluorescence was determined. Chlorophyll, anthocyanin, and flavonol content were also measured. In two-year field studies, the effect of the same preparations on plant height, grain yield, thousand-grain weight, oil, protein, and starch content in the grain was determined. It was shown that appropriately selected biostimulants have a positive effect on plant growth, physiological parameters, and the yield of maize grain. The impact of preparations on the grain yield depended on the conditions that prevailed in the growing season. Full article

We identified strains of lactic acid bacteria from fermented potherb mustard that showed excellent fermentation properties. The goal was to identify superior starter cultures that would optimize the traditional fermentation process, reduce fermentation duration, and improve the quality of pickled potherb mustard. Four strains were screened: Weissella cibaria (LAB1, LAB3) and Leuconostoc mesenteroides (LAB2, LAB4). Then, after in vitro tests of tolerance to low pH and salt levels as well as lactic acid production ability, nitrite degradation ability, antibacterial properties, and antioxidant activity, LAB1 and LAB2 were selected as the best strains. Next, these two strains were used as starter cultures for fermenting potherb mustard. Each was inoculated into the fermentation solution. Compared to natural fermentation, both showed beneficial effects, including reducing nitrite content, shortening fermentation time, maintaining the reducing sugar, and increasing the levels of nitrogenous amino acids. Microbial diversity analyses revealed that, prior to fermentation, the predominant microbial communities were Methylobacterium and Sphingomonas, which primarily originated from the surrounding environment. However, 30 days after inoculation with the two strains, there was a significant increase in the abundance of Weissella and Lactobacillus, and Weissella emerged as the dominant bacterium. Inoculation of LAB1 effectively stabilized the bacterial community of the potherb mustard and significantly enhanced the content of nitrogenous amino acids in the final product, indicating that it is highly suitable as a mono-starter. On the other hand, LAB2 led to reduced nitrite content and facilitated the proliferation of Weissella and Lactobacillus, indicating that it is an effective mixed starter. Due to its limited effect on acid production, it is not recommended as a mono-starter for pickled mustard production. Full article

Channel catfish (Ictalurus punctatus) is a widely consumed freshwater fish known for its nutritional value but is highly prone to spoilage. This study investigated the quality changes of catfish muscle tissue under refrigeration and freezing through physicochemical, metabolomic, and microbial analyses. Results revealed that sensory scores decreased significantly during storage, with frozen samples maintaining similar scores to refrigerated ones after extended periods. Protein degradation and lipid oxidation, indicated by TVB-N and TBARS levels, were more pronounced during prolonged freezing. Metabolomic profiling identified 261 differential metabolites under long-term freezing, including elevated phosphatidylcholines, sphingomyelins, and disrupted amino acid pathways. Shifts in spoilage-associated microbial genera, such as Pseudomonas, and the correlations between microbial genera and specific metabolites, such as Methylobacterium with methylmalonic acid, highlighted microbial-driven spoilage processes. These findings provided a comprehensive understanding of quality deterioration during storage, guiding the development of enhanced preservation strategies for aquatic products. Full article

This study aims to evaluate the potential of a nitrogen-fixing endophyte, Methylobacterium symbioticum SB23, as a sustainable biofertilizer in peach (Prunus persica) cultivation. We compared three treatments: a control with soil application of ammonium sulfate (250 kg ha⁻¹) and two endophyte foliar applications at different doses: a single high-dose application (M.SYM500 at 500 kg ha⁻¹) and a split half-dose application (M.SYM250 at 250 kg ha⁻¹ applied twice). The first application was made at the fruit stage’s appearance, and the second when the fruits were fully developed. Key assessments included chlorophyll content and shoot growth, which were evaluated at 52 and 100 days after application (DAA), with continued growth benefits observed through 193 DAA. Evaluations were conducted of fruit characteristics, amino acid profiles, and plant tissues of leaves for nitrogen and phosphorus at 107 DAA (harvest). The M.SYM500 treatment notably enhanced fruit weight and increased specific amino acids, such as glutamic acid, methionine, and phenylalanine, contributing to improved fruit quality and resistance properties. No significant differences in °Brix (total soluble solid) levels were observed among treatments, indicating that photosynthetic gains were likely directed towards biomass and structural growth rather than sugar accumulation. This study demonstrates that nitrogen-fixing endophytes can be effective in reducing reliance on synthetic fertilizers while sustaining or improving peach growth and fruit quality. Full article