Search Results (876)

Streptomyces is a versatile genus widely used in drug production and biotechnological applications. This study aimed to identify and characterize bioactive compounds produced by Streptomyces UP-AC4 and UP-3.2 strains and evaluate their antibacterial and anticancer activities. The strains were identified as Streptomyces californicus and Streptomyces purpurascens via chemotaxonomy, 16S rRNA sequencing, amplified ribosomal DNA restriction analysis, and phylogenetic analysis. Bioactive compounds were extracted using heat treatments at 63 °C for 30 min or 73–110 °C for 10 min. Antibacterial activity against Staphylococcus aureus, Bacillus cereus, and Escherichia coli was assessed by agar disc assay, with MICs of 0.024–0.195 mg/mL and MBCs of 0.098–0.391 mg/mL for the most effective extracts. Anticancer activity against A549, H1299, and Lu99 lung cancer cells was evaluated using the MTT assay, showing IC₅₀ values of 0.23 ± 0.06 to 4.85 ± 0.64 mg/mL, while exhibiting no toxicity to normal fibroblast cells. HPLC analysis indicated that heat-assisted extraction of UP-AC4 at 73 °C for 10 min enriched a dinactin-associated compound as a predominant metabolite with antibiotic and anticancer activities. In conclusion, Streptomyces UP-AC4 and UP-3.2 produce promising low-cost bioactive compounds with strong potential for pharmaceutical and healthcare applications. Full article

Microorganisms have emerged as prolific and versatile producers of steroidal natural products, displaying a remarkable capacity for structural diversification that extends far beyond classical sterol frameworks. This review critically examines steroidal metabolites isolated from microbial sources, with a particular emphasis on marine-derived and endophytic fungi belonging to the genera Aspergillus and Penicillium, alongside selected bacterial and lesser-studied fungal taxa. Comparative analysis reveals that these organisms repeatedly generate distinctive steroid scaffolds, including highly oxygenated ergostanes, secosteroids, rearranged polycyclic systems, and hybrid architectures arising from oxidative cleavage, cyclization, and Diels–Alder-type transformations. While many reported compounds exhibit cytotoxic, anti-inflammatory, antimicrobial, or enzyme-inhibitory activities, the biological relevance of these metabolites varies considerably, highlighting the need to distinguish broadly recurring bioactivities from isolated or strain-specific observations. By integrating structural classification with biosynthetic considerations and bioactivity trends, this review identifies key steroidal frameworks that recur across taxa and appear particularly promising for further pharmacological investigation. In addition, current gaps in mechanistic understanding and compound prioritization are discussed. Finally, emerging strategies such as genome mining, biosynthetic gene cluster analysis, co-culture approaches, and synthetic biology are highlighted as powerful tools to unlock the largely untapped potential of microbial genomes for the discovery of novel steroidal scaffolds. Together, this synthesis underscores the importance of microorganisms as a dynamic and expandable source of structurally unique and biologically relevant steroids, and provides a framework to guide future discovery-driven and mechanism-oriented research in the field. Full article

Microbial communities found in arid environments often exhibit unique genetic and metabolic adaptations that enable them to synthesize potent bioactive compounds. Bacillus thuringiensis (Bt) is widely recognized for its biocontrol potential against various insects. This study aims to investigate the insecticidal potential of Bt strains isolated from Qatar’s soil against dipteran and lepidopteran larvae. The microscopic analysis identified distinct crystal types, including bipyramidal, cuboidal, spherical smooth, and spherical rough forms, with distinct cry, cyt, and vip genes. Strains producing bipyramidal crystals carry cry1A, cry2A, and vip3A genes, while only two strains producing spherical crystals carry cry4B and cyt1A genes. Bipyramidal crystal-producing strains (QBT552 and QBT877) showed potent insecticidal activity, achieving 100% mortality against Corcyra cephalonica larvae, with LC₅₀ values of 25 µg/g. Spherical smooth crystal-producing strain (QBT862) exhibited high toxicity against Culex pipiens insect larvae (LC₅₀ = 2 µg/L). The quantification of bipyramidal crystal protein production of strains QBT877 and QBT552 exhibited the highest δ-endotoxin yield (1334.4 ± 6.7 and 1188.7 ± 5.0 µg/mL, respectively), while smooth spherical crystal strains QBT758 and QBT862 were 577.5 ± 8.4 and 567.6 ± 8.4 µg/mL, respectively. These findings highlighted the potential of Bt QBT strains for biocontrol applications, with strains showing promise for producing effective δ-endotoxins. Full article

Salmonella enterica from low-moisture food has been found to have a higher thermal tolerance than from high-moisture food. However, the molecular mechanism underlying the association of thermal tolerance of this pathogen with low-moisture foods, such as peanut butter and peanut spread, has not been fully elucidated. We previously found that mutants of S. Tennessee with a defective gene encoding a cell membrane lipoprotein (Lpa) or cell division protein (ZapC) formed significantly (p ≤ 0.05) less biofilm than the wildtype strain. To assess the possible role of these genes in the thermal tolerance of S. Tennessee, this study compared the surviving populations of the wildtype S. Tennessee and its mutants defective in Lpa or ZapC in different types of peanut products (regular, reduced-fat, and natural) at 74 °C for 0, 2.5, 5, 10, 15, 20, 30, 40, or 50 min. Results showed that mutants with a defective lpa or zapC significantly affected the survival of Salmonella in peanut products during heat treatments. Significantly, a higher reduction in Salmonella population was observed in regular peanut butter, followed by natural and reduced-fat peanut spreads. The study provides new insight into one of the molecular mechanisms underlying the thermal tolerance of Salmonella enterica. Full article

Streptococcus pneumoniae (S. pneumoniae) is responsible for a wide range of infections. The aim of this study was to investigate the clonal diversity of S. pneumoniae in thirteen Arab countries. Multi-Locus Sequence Typing (MLST) data were extracted from PubMLST database. Genetic analysis was performed using DnaSP software version 6.0. A Minimum Spanning Tree (MST) analysis was conducted to evaluate the population structure of S. pneumoniae strains. Genetic data from 1008 Arab S. pneumoniae strains, collected over 22 years (1996–2018), were analyzed. MLST analysis identified a highly diverse population comprising 600 sequence types grouped into 87 clonal complexes and 295 singletons. Both internationally disseminated clones (e.g., ST156) and country-specific lineages (e.g., ST2307, Saudi Arabia) were observed, indicating substantial geographic structuring. Significant associations were detected between sequence types and geographical origin, decade of isolation, patient age, disease type, and serotype (p < 0.05). Although recombination events were presented, the population retained a predominantly clonal structure over time (I^S_A = 0.0715, p < 0.001). Overall, these findings demonstrated extensive genetic heterogeneity and spatiotemporal structuring of S. pneumoniae in the Arab region, providing valuable insights for regional surveillance and vaccine-related strategies. Full article

Bacterial urinary tract infections (UTIs) are common in dogs and cats. This study examined the correlations between routine urinalysis and culture-confirmed infections and described the etiologic agents and antimicrobial susceptibility to support stewardship. In 2023, 1787 urine samples (854 dogs, 933 cats) underwent urinalysis, aerobic culture with species identification, and disk-diffusion testing per Clinical and Laboratory Standards Institute standards; non-parametric statistics with effect sizes were applied. Pyuria was the strongest correlate of infection in both species. Low urine specific gravity was associated with infection and crystal detection, and urine pH correlated weakly with growth in dogs. Nitrite positivity was strongly associated with infection in dogs but showed no diagnostic value in cats. Hematuria showed a weak inverse association in dogs and no association in cats. Females and older animals were more frequently infected, and infections were slightly more common in summer. Most episodes were monomicrobial (85%), predominantly caused by Escherichia coli (48.4% of dogs; 51.5% of cats). E. coli remained broadly susceptible to nitrofurantoin and aminoglycosides. Fluoroquinolone activity was variable. Pseudomonas spp. showed the highest susceptibility to ceftazidime, cefepime, and aminoglycosides. These findings support culture when pyuria, dilute urine, or nitrite positivity is detected and favour short, targeted empiric therapy pending results, guided by a stepwise clinical decision pathway. Full article

This study involved a systematic literature review using bibliometric analysis to examine the evolution and current trends of Biological Remediation studies. The bibliometric analysis was used for the descriptive, intellectual, social, and conceptual network analyses, while systematic reviews were used to identify the application of the Biological Remediation. A total of 4835 papers were selected and extracted from Scopus between 2020 and 2025. The publication trends, most influential countries and articles, leading journals, collaboration networks, coupling networks, and application of the Biological Remediation in various disciplines were described. This study summarized the research agenda of the Biological Remediation field, which would be helpful for researchers and funding agencies. This article highlights four new research directions in Current Bioremediation Trends: (1) understanding the interactions between petroleum hydrocarbons and heavy metals in composite pollution systems; (2) exploring microbial community succession during bioremediation; (3) utilizing biosurfactants to enhance contaminant solubilization and biodegradation; and (4) developing integrative, multi-mechanistic remediation approaches. Full article

Cave ecosystems represent environmentally constrained habitats that host diverse and highly specialized fungal communities. Many cave-dwelling fungi act as decomposers, transient colonizers, or cave fauna symbionts. During a mycological survey of Sesalačka cave (Serbia), a previously undescribed species was isolated from the skin of a Miniopterus schreibersii. The aim of this study was to characterize this isolate using an integrative taxonomic approach combining morphology, physiology, and multilocus phylogenetics. The fungus was cultured on different media under and its morphophysiological traits were recorded. DNA sequences of ITS, LSU, SSU, and TEF1α were compared with existing Gamsia species and phylogenetic analysis placed the isolate within the Gamsia clade, forming a well-supported lineage the most closely related to G. aggregata, but differing from it by 8–12 base pairs across loci. Distinctive morphological features of this species include obovoid to pyriform polyblastic conidia, hyaline to pale-brown annelloconidia, and reduced conidiophores, clearly separating the species from described congeners. It is psychrotolerant and does not grow at 37 °C, suggesting it is a cave-associated saprobe rather than a mammalian pathogen. This study expands the known diversity of Gamsia species and contributes to the growing evidence that subterranean habitats harbor numerous undescribed fungal kingdom members. Full article

Inappropriate use of antibiotics can stimulate antimicrobial resistance, since bacteria are capable of circumventing pharmacological action through various resistance mechanisms. Recently, during the COVID-19 pandemic, there has been an increase in the use of antimicrobials. This is an analytical, quantitative, and retrospective study on bacterial resistance and mortality in Intensive Care Unit (ICU) patients from 2017 to 2022. This study analyzed sociodemographic aspects, clinical, and laboratory parameters in patients admitted to the ICU. A total of 221 medical records of patients with multidrug-resistant bacteria in the ICU were included, with an outcome of 95 discharges (42.98%) and 126 deaths (53.01%). An increase in the prevalence of bacterial resistance in the ICU was identified during the Pandemic period, when compared to the Pre-Pandemic period. It was identified that the increase in bacterial resistance of some pathogens was associated with death. It was also observed that age was a factor for an increased risk of mortality in the ICU, no matter the sex of the patient. Importance of careful analysis in the use of antimicrobials, as well as in the care of ICU patients and in the surveillance of bacterial infections by health professionals. Full article

Kuwait faces a significant public health challenge from obesity and Type 2 Diabetes Mellitus (T2DM), conditions known to disrupt the natural balance of oral bacteria. This imbalance, or dysbiosis, can promote gum disease and may worsen metabolic health. While the intragastric balloon (IGB) is a common, less invasive weight-loss procedure, its specific effect on the community of bacteria in saliva remains unclear, especially for high-risk groups. The objective of this study was to investigate changes in the salivary microbiota of obese prediabetic patients following IGB placement. We recruited 20 obese patients (11 female, 9 male; average age 31.5) from a clinic in Kuwait. Saliva samples were collected just before IGB (Allurion™) insertion and again 6 weeks after that. Using 16S rRNA gene sequencing, we identified the bacterial species present and used bioinformatic tools to analyze diversity and abundance. Our analysis revealed that the overall diversity and structure of the salivary microbial community remained stable after the procedure. However, we detected notable changes in specific types of bacteria. The relative abundance of several genera, including Veillonella, Porphyromonas, and Fusobacterium, shifted significantly. At the species level, Porphyromonas pasteri and Haemophilus parainfluenzae became less abundant, while certain Veillonella and Streptococcus species increased in number after the IGB was placed. In conclusion, for obese prediabetic patients in Kuwait, the salivary microbiome demonstrates remarkable stability in the weeks following IGB surgery. The procedure did not drastically alter the overall ecosystem, but it did trigger specific, subtle changes in certain bacterial populations. This suggests the oral microbiota is resilient, adapting to the new physiological conditions without a major upheaval. Full article

Pseudomonas extremorientalis PEY1, isolated from the intestinal contents of marine fish, was evaluated for the production and properties of antibacterial proteins active against Edwardsiella tarda, a major pathogen in aquaculture. Antibacterial production was maximized in a minimal medium supplemented with 1% yeast extract and 1% galactose under stationary cultivation at 25 °C and pH 7.0. Growth and bioactivity assays were conducted under varying carbon and nitrogen sources, temperatures, and pH levels. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis revealed a distinct ~37 kDa protein band corresponding to antibacterial activity, exhibiting an inhibition zone of 2.4 ± 0.1 cm against E. tarda. The activity was completely abolished by papain digestion but remained detectable after exposure to 55 °C and pH 8, indicating that the active compound is a moderately heat-stable, proteinaceous antibacterial molecule. LC–MS/MS analysis identified the protein as a putative disulfide reductase with ~40% sequence coverage. The antibacterial factor exhibited strong physicochemical stability, retaining activity in the presence of surfactants and metal ions. Collectively, these findings demonstrate that P. extremorientalis PEY1 produces a thermostable, papain-sensitive antibacterial protein with selective activity against E. tarda, highlighting its potential as a promising natural biocontrol or postbiotic candidate for sustainable aquaculture. Full article

In forest soils, nitrogen (N) is present in inorganic and organic forms. The organic forms include monomeric amino acids, but also polymers such as chitin. Ectomycorrhizal fungi are known to take up both inorganic and organic N forms, and to depolymerize large organic compounds; however, it is unknown if the compounds are used for growth. The aim of this investigation was to determine the growth of a range of ectomycorrhizal fungi on inorganic and organic N sources. Seven ectomycorrhizal fungi and one endophyte originating from mountain regions either in Austria, Mongolia, or Slovenia were grown in in-vitro cultures containing ammonium, nitrate, or chitin. Four ectomycorrhizal fungi were used to investigate growth on amino acids. All fungi, except Paxillus involutus, utilized nitrate as a N source. All fungi also grew on both chitin and N-acetylglucosamine, the amino sugar precursor of chitin. Paxillus involutus and Melanogaster broomeanus showed enhanced growth on chitin-containing media. Amanita muscaria, Rhizopogon roseolus, and Suillus granulatus, but not Paxillus involutus, were able to utilize the amino acids glycine and glutamate, as well as the tripeptide triglycine. The ability to utilize the different N sources was independent of the origin of the fungi. Full article

Fumonisins, a major class of mycotoxins, pose significant health risks to humans and animals due to their widespread contamination and potent toxicity. Recent advances in molecular biology, biochemistry, and enzymology have greatly enhanced the understanding of fumonisin biosynthesis and its genetic regulation. The key biosynthetic genes are typically organized in clusters and regulated by specific transcription factors; increasing evidence also highlights the involvement of complex transcriptional and epigenetic mechanisms. Environmental factors such as nitrogen, carbon, and pH also modulate these regulatory networks. Despite substantial progress, critical gaps remain in fully elucidating the regulatory pathways that control fumonisin production. This review synthesizes current knowledge regarding fumonisin biosynthesis, gene clusters, and multi-level regulatory mechanisms, while emphasizing recent trends, existing challenges, and potential applications in food safety and biotechnology to enhance food security and promote sustainable development. Full article

Ureaplasma species are associated with various reproductive health issues, while human papillomavirus (HPV) is associated with cervical, vaginal and vulvar cancers. Data on the association between Ureaplasma species and HPV are limited in South Africa. This study investigated the prevalence of Ureaplasma urealyticum (U. urealyticum), Ureaplasma parvum (U. parvum), and HPV coinfection and their associated factors, among adolescent girls and young women (AGYW) in the Eastern Cape Province, South Africa. A total of 214 participants were retrospectively recruited, and secondary data on HPV, U. urealyticum, U. parvum, demographics, and sexual behavior were used. HPV was detected using the Roche Linear Array HPV Genotyping Test, while U. urealyticum and U. parvum were detected using Allplex™ sexually transmitted infection (STI) essential Assay. Statistical analyses were performed using GraphPad Prism Version 8.0.1.244. The prevalence of U. urealyticum was 43.9% (94/214) and increased significantly with age (p = 0.036, R² = 0.8497); while U. parvum prevalence was 68.7% (147/214) and was not influenced by age. Having four to six lifetime sexual partners (PR: 1.77, 95% CI: 1.04–3.00, p = 0.043) was associated with increased risk of U. urealyticum. A proportion of 36.3% (77/212) had HPV-U. urealyticum coinfection and its risk was increased among those with 3–6 lifetime sexual partners (PR: 1.59, 95% CI: 1.10–2.53, p = 0.017), 2–4 new partners past three months (PR: 2.14, 95% CI: 1.19–2.42, p = 0.021); vaginal sexual intercourse frequency past 1-month (2–3 vaginal intercourse: PR: 1.54, 95% CI: 1.06–2.53, p = 0.037; 4–10 vaginal intercourse: PR: 1.91, 95% CI: 1.83–1.91, p = 0.005) and alcohol consumption (PR: 1.85, 95% CI: 1.20–3.28, p = 0.004). U. urealyticum positives had a significantly higher risk of HPV types targeted by Cervarix^® HPV vaccine than negatives (PR: 2.56, 95% CI: 1.23–5.37, p = 0.013), Gardasil^®4 (PR: 2.16, 95% CI: 1.25–3.75, p = 0.006) and Gardasil^®9 (PR: 1.70, 95% CI: 1.25–2.32, p = 0.001). AGYW of Eastern Cape Province, South Africa had high prevalence of U. urealyticum-HPV and U. parvum-HPV coinfections. Ureaplasma species coinfection was associated with HPV prevalence and distribution of genotypes. The U. urealyticum prevalence and its coinfection with HPV were associated with sexual behavior. Data from this study could contribute to the design of sexual health and STI interventions and could serve as a baseline for future epidemiological studies, which include ongoing surveillance of HPV genotype prevalence to evaluate the impact and effectiveness of HPV vaccination programs in the population. Full article

The Veracruz Reef System National Park (VRSNP), located in the central Gulf of Mexico, is one of the country’s most ecologically and economically significant coral systems. Despite its high biodiversity and ecosystem functionality, it is affected by anthropogenic inputs such as fluvial discharges, urban effluents, and port and tourism activities that contribute organic and bacteriological loads. This study aimed to identify the presence of Enterococcus spp. and Vibrio spp. during three climatic seasons—dry, rainy, and north winds—at two water column depths (surface and bottom) across three reefs (Enmedio, Chopas, and Gallega) within the VRSNP during the 2022 annual cycle. Samples were analyzed according to national and international standards. Results showed that Vibrio spp. were influenced mainly by temporal factors, with higher values during north winds and the dry season (>1100 MPN/100 mL); otherwise, rainy conditions reported the lowest load (184.89 ± 15.00 MPN/100 mL). While Enterococcus spp. exhibited greater spatial influence, particularly in surface waters, Enmedio Reef recorded the highest load (478.34 ± 37.28 CFU/100 mL); in addition, Chopas Reef reported the lowest at the bottom (12.43 ± 1.26 CFU/100 mL). The findings highlight the need to strengthen microbiological monitoring protocols in marine coastal ecosystems to assess water quality, public health risks, and the ecological integrity of coral reef environments, as well as the implementation of molecular identification techniques. Full article