Brazilian Journal of Microbiology最新文献

Background: This study aimed to investigate the healing and anti-inflammatory potential of the Lactiplantibacillus plantarum 6.2 (Lp62) strain, administered orally in a murine model of medication-related osteonecrosis of the jaw (MRONJ).

Materials and methods: Twenty male Wistar rats (N = 20) were randomly assigned to four groups (n = 5 per group): negative control (BASAL), healthy rats supplemented with Lp62 (LAC), experimental osteonecrosis (ONE), and osteonecrosis supplemented with Lp62 (ONE+LAC). Over an 8-week period, MRONJ was induced by intraperitoneal injections of zoledronic acid (250 μg/kg), except in the BASAL group, which received sterile 0.9% saline solution. This was followed by extraction of the left mandibular first molar. Lp62 supplementation (10⁹ CFU/mL) was administered daily by oral gavage during the 3rd and 7th weeks. At the end of the experimental period, animals were euthanized, and mandibles were examined macroscopically for exposed bone and epithelial closure. Histological evaluation included hematoxylin-eosin and Masson's trichrome staining, while immunohistochemical analysis was performed using anti-NF-κB and anti-TGF-β antibodies. Macroscopic and histomorphometric data were analyzed by one-way ANOVA followed by Tukey's or Dunnett's post hoc tests (p < 0.05).

Results: Epithelial closure and osteocyte preservation were evident in the BASAL, LAC, and ONE+LAC groups. In contrast, the ONE group exhibited no repair and showed higher NF-κB immunolabeling. Extracellular matrix (ECM) deposition was more pronounced in the Lp62-supplemented groups, which also demonstrated increased TGF-β immunolabeling.

Conclusion: Oral supplementation with Lp62 promoted bone and epithelial regeneration, reduced NF-κB immunolabeling, and upregulated TGF-β in mandibular tissues, suggesting significant anti-inflammatory and reparative potential in experimental MRONJ lesions in rats.

The sentence "Although efflux pump and mecC genes have been documented…" has been corrected to "Although efflux pump genes and mecC have been documented…" to improve grammatical parallelism and scientific clarity. The gene name tet38 has been standardized throughout the manuscript as tet(38) to ensure consistent nomenclature.

Bovine tuberculosis, caused by Mycobacterium bovis, is a major One Health concern, impacting livestock, wildlife, and humans. The complete genetic and lineage characterization of M. bovis strains is lacking in many parts of the world, including India. This study reports Illumina sequencing and the first draft genome of M. bovis strain 3/86Rv isolated from a cross-bred cow in India in 1986 and kept under in vitro passages. The genome assembly produced a single contig of 4,303,074 bp with excellent coverage (99.66%) and completeness, and 97.6% of BUSCO genes were conserved.The genome annotation identified 4,246 coding sequences (CDS). Orthologous cluster analysis revealed high protein conservation among M. bovis strains, with unique genes observed in M. tuberculosis. The subsystems analysis highlighted a significant enrichment of genes related to metabolism, protein processing, and virulence. Phylogenetic analysis placed M. bovis strain 3/86Rv within a closely related cluster of M. bovis isolates and distinct from other MTBC species, such as M. kansasii, which is a more recent outlier. SNP analysis compared with M. bovis AN5 revealed 171 SNPs, with a predominance of missense mutations and a Ts/Tv ratio of 1.11, suggesting adaptive evolution. The study underscores the genetic diversity and complex resistance mechanisms of M. bovis, providing valuable insights into its pathogenicity and evolutionary trajectory. This comprehensive genomic characterization will aid in understanding the biology of M. bovis.

Halotolerant bacteria possess significant scientific and biotechnological potential due to their ability to thrive in high-salinity environments and withstand other harsh conditions. Their adaptive mechanisms-such as the production of specialized enzymes, and biosurfactants-enable applications in bioremediation, saline wastewater treatment, and industries like food, medicine, and detergents. Notably, these bacteria can tolerate not only NaCl but also other salts, including perchlorates, which are highly toxic and abundant on Mars, where they contribute to liquid water stability. In this study, we isolated halotolerant bacteria from underexplored mangrove and restinga sites in Camocim, Ceará, Brazil, and investigated their potential for biotechnological and astrobiological applications. We assessed their tolerance to NaCl and perchlorate, as well as their ability to produce biosurfactants and enzymes (amylase, lipase, and protease). Additionally, we evaluated their capacity to grow under anoxic conditions using sodium perchlorate as a terminal electron acceptor-a key trait for survival in Mars-like environments. Among the 20 isolates, predominantly identified as Bacillus sp., all tolerated NaCl concentrations up to 2.57 M, with Bacillus sp. CaSS7 growing at the maximum tested concentration of 3.42 M. Additionally, most strains also withstood sodium perchlorate at 0.783 M. All isolates produced at least one tested enzyme, and five were biosurfactant producers. Furthermore, their ability to utilize perchlorate as an electron acceptor under anoxic conditions highlights their potential relevance in astrobiology. This study underscores the importance of expanding bioprospecting efforts to uncover novel applications of halotolerant bacteria and sets the foundation for future research in biotechnology and planetary science.

Environmental pollution caused by crude oil contamination poses a major ecological threat, highlighting the need for sustainable bioremediation approaches. Biosurfactants produced by actinobacteria offer promising advantages due to their eco-friendly and multifunctional properties. In this study, soil samples were collected from oil contaminated sites in and around Salem, Tamil Nadu, India. Eight morphologically distinct isolates were screened based on β-hemolysis, oil displacement, emulsification index, and lipase activity. Among them, strain AS1 demonstrated the highest biosurfactant activity. Molecular identification through 16 S rRNA gene sequencing confirmed that AS1 belongs to the genus Streptomyces and submitted to GenBank with an accession number-MT525319. The potent strain exhibited strong crude oil degradation capabilities, achieving 95.9% degradation after 168 h as determined by hydrocarbon utilization tests, DCPIP assay, and gravimetric analysis. The biosurfactant extracted from strain AS1 showed notable antibacterial activity against Staphylococcus aureus, Bacillus subtilis, and Escherichia coli, with low minimum inhibitory concentrations, and demonstrated considerable antioxidant potential with 70.04% DPPH radical scavenging activity at 500 µg/ml. Purification by dialysis yielded a partially purified biosurfactant that was characterized by TLC, FT-IR, and GC-MS analyses. FT-IR spectra revealed the presence of functional groups such as alkanes and carboxylic acids, while GC-MS identified several bioactive compounds, including 1-tetradecanol and phthalic acid derivatives. These findings suggest that Streptomyces sp. AS1 strain is a promising candidate for crude oil bioremediation and the development of biosurfactant based applications in pharmaceutical and environmental industries.

Traditional dairy products (TDP) are a valuable source of lactic acid bacteria (LAB) for use in sustainable and natural food systems. This study examined the technology and biopreservative properties of LAB isolated from 167 dairy samples across 11 regions of Morocco. Among the 2,672 pure isolates, 531 presumptive LAB were selected for laboratory phenotypic evaluation, focusing on milk acidity, enzyme activities, stress resistance, and antibacterial efficacy against foodborne microorganisms. The acidity test revealed considerable intraspecies variability; notably, the top-performing outliers were isolates of Enterococcus faecalis and Lactococcus lactis, predominantly derived from Lben and the Tetouan region. Significant heterogeneity was also observed in enzymatic activity, with approximately 70% exhibiting proteolytic activity, 22% lipolytic activity, 43% esterolytic activity, and 42% amylolytic activity. In terms of inhibitory activity, 32% of the LAB isolates showed inhibition against the tested pathogens, with noteworthy suppression observed against Staphylococcus aureus (13%) and Listeria monocytogenes (15%). The most potent antibacterial activity was identified in isolates of Enterococcus faecium, Lactiplantibacillus plantarum, and L. lactis, which were isolated from Lben (Agadir), Milk (Fes), and Raib (Fes), respectively. Principal component analysis (PCA) and clustering identified three distinct functional clusters of isolates, shaped by geographical origin and dairy products type, with specialized traits in acidification, stress resilience, or enzymatic activity. Representative isolates (n = 84) from key clusters were identified by 16 S rRNA sequencing, encompassing 15 LAB species, dominated by L. lactis, Leuconostoc mesenteroides, Enterococcus spp. and Lpb. plantarum. This work represents the first extensive screening of LAB from Morocco, providing a valuable collection of strains and a foundational framework for developing tailored autochthonous starter or adjunct cultures for improved dairy fermentation and biopreservation.