Search Results (946)

In producing docosahexaenoic acid (DHA) with Schizochytrium sp., the production yield of DHA can be effectively increased through using hydrogen peroxide (H₂O₂) and controlling its concentration at the desired level, since H₂O₂ is a common regulatory mediator for lipid accumulation in oleaginous microorganisms. However, when exposed to the environment of oxidative stress induced by the long-term exogenous addition of H₂O₂ over an extended time span, cells’ metabolic activity would be gradually decreased or even stopped, which ultimately results in a limited duration for producing DHA efficiently. In fact, the severe accumulation of ROS cannot be avoided when implementing the normal DHA fermentation batch without the use of exogenous H₂O₂ because of the necessity of supplying a mass of oxygen for cell respiration. Aiming to overcome these issues, a novel periodic feeding strategy for H₂O₂ and p-aminobenzoate was proposed, and the underlying principle of this strategy is that the substantial harm inflicted on cells due to their continuous exposure to the oxidative stress environment can be effectively alleviated through the implementation of a recovery treatment (p-aminobenzoate, reducing agent) subsequent to the environmental stimulus. When using this strategy, it was achieved that, concurrently, activities of the vital enzymes participating in lipid biosynthesis were maintained at their maximum levels and the maintenance coefficient of glucose reduced to its minimum level (0.0034 1/h vs. 0.0027 1/h) by controlling ROS concentration at lower and desired levels, and thus DHA concentration reached the maximum value of 1.49 ± 0.20 g/L, with a 49% increase compared to the control group. Full article

Continuous cropping obstacles (CCOs) lead to a decline in yield and quality under repeated cultivation in the same farmland. Notably, CCOs caused by fusarium wilt, autotoxicity, or imbalance in rhizosphere microbial communities reduce the productivity of watermelons (Citrullus lanatus). Considering the negative environmental impacts of conventional agrochemicals, it is necessary to evaluate the biocontrol efficiency of microorganisms. Therefore, this study aimed to investigate the biocontrol efficiency of Bacillus amyloliquefaciens strain PP19 against CCOs of watermelon so as to develop alternatives to agrochemicals. The inhibitory effect of PP19 on watermelon fusarium wilt was assessed through plate confrontation assays and field trials. The degradation and utilization of autotoxins by PP19 were examined via co-culture experiments. Additionally, 16S rRNA sequencing was employed to analyze the impact of PP19 on the rhizosphere soil microbial community of watermelon. Specifically, we analyzed the PP19 utilization of four phenolic autotoxins secreted by watermelon roots and assessed their effects on microbial diversity in the watermelon rhizosphere. Plant growth assays showed that PP19 improved the weight and quality of watermelon fruit. Although PP19 inhibited the growth of Fusarium oxysporum f. sp. niveum (Fon), the growth inhibitory effect was significantly enhanced by autotoxins produced by watermelon, including mixed phenolic, cinnamic, ferulic, and p-coumaric acids. Additionally, PP19 effectively degraded and utilized the autotoxins, and the autotoxins enhanced PP19’s swimming ability and biofilm formation. Moreover, PP19 treatment significantly enhanced the microbial diversity in watermelon rhizosphere, increased the number of beneficial bacterial genera, and decreased the number of pathogenic genera. Conclusively, these results suggest that B. amyloliquefaciens strain PP19 improves the resistance of watermelon to CCOs by effectively utilizing and degrading autotoxin, altering soil microbial community structure, and inhibiting Fon17 growth, resulting in improved fruit quality. Overall, PP19 possesses potential application as a biological control agent against CCOs in commercial watermelon cultivation. Full article

Tomato (Solanum lycopersicum) is an essential crop worldwide, yet it remains highly vulnerable to severe fungal and bacterial diseases. Traditional chemical-based disease management strategies, aimed at controlling these diseases face increasing scrutiny, due to concerns regarding pathogen resistance, environmental degradation, and potential health risks to humans. This has catalyzed the exploration of sustainable alternatives, with biological control emerging as a viable and promising strategy. Endophytic and epiphytic microorganisms are pivotal as biocontrol agents (BCAs), employing diverse strategies, such as generating antimicrobial substances, enzymes, and volatile organic compounds (VOCs), to suppress pathogen growth and enhance plant health. The efficacy of these antagonistic microorganisms is influenced by the cultivation systems employed, with significant variations observed between soil and hydroponic environments. Factors such as nutrient dynamics and microbial interactions play crucial roles in determining the success of BCAs in these different settings. The advent of metagenomic tools has transformed the landscape of microbial community research, facilitating the identification of functional genes associated with antagonistic activities and the adaptation of these microorganisms to diverse environmental conditions. This review aims to elucidate the potential of endophytic and epiphytic microorganisms in biological control, examining their mechanisms of action, the impact of cultivation systems on their effectiveness, and the application of metagenomics to optimize their use in sustainable disease management strategies for tomato crops. Full article

Pseudomonas aeruginosa and Staphylococcus aureus are highly resistant microorganisms that contribute to prolonged hospital stays and increased mortality. Developing new antimicrobial agents is essential to address this global health challenge. Nanoemulsions (NE) containing essential oils (EOs) and phenolic compounds with antimicrobial activity represent a promising alternative. This study reports, for the first time, the formulation of a NE containing Cymbopogon flexuosus and eugenol (NECE) and its antimicrobial activity against P. aeruginosa and S. aureus. NECE exhibited suitable physicochemical properties (mean size < 200 nm, PDI < 0.3, and negative zeta potential) and remained stable for 90 days at 4 °C while maintaining antimicrobial activity. It showed bactericidal effects at 2.5 mg/mL against P. aeruginosa and 0.625 mg/mL against S. aureus. Moreover, NECE improved the biocompatibility of the free oil (FO) in Peripheral Blood Mononuclear Cells (PBMCs). Altogether, these findings demonstrate, for the first time, that NECE is a stable nanoemulsion with enhanced antimicrobial activity and biocompatibility, supporting its potential as a safe and effective topical strategy against wound-associated pathogens. Full article

Tuberculosis (TB), an infection caused by Mycobacterium tuberculosis, affects nearly one-third of the world’s population. It is estimated that TB infects around ten million people worldwide, with no less than two million fatalities annually. It is one of the treatable infections due to improved diagnostic tools and therapeutic agents. However, the disease remains a threat to humankind due to the emergence of multidrug- and extensively drug-resistant strains of M. tuberculosis. This has driven many researchers to look for new antitubercular medications with better efficacy, safety, and affordability. As has always been the case, natural products have provided huge potential as a source of remedies for various infectious and non-infectious diseases. This review aims to report discoveries and updates of antitubercular natural products with minimum inhibitory concentration (MIC) values of less than or 10 µg/mL or 50 µM and selectivity indices of greater than 10. The review discusses 36 naturally occurring compounds from various classes, isolated from both terrestrial and aquatic organisms, including higher plants and microorganisms. Perusal of the literature reveals that most of these promising compounds are alkaloids, terpenoids, steroids, and peptides. Rufomycin I, a cyclic heptapeptide from Streptomyces sp., showed potent activity against drug-sensitive and isoniazid-resistant M. tuberculosis H37Rv (MIC < 0.004 µM), surpassing isoniazid (MIC = 0.23 µM), likely by inhibiting ClpC1 transcription. Hapalindole A also displayed strong activity (MIC < 0.6 µM). Current TB drugs have become less effective; therefore, natural products such as hapalindole A and rufomycin I, owing to their potent activity, selectivity, and novelty, are increasingly recognized as potential lead compounds against TB. Full article

The human gastrointestinal tract contains a complex and diverse community of microorganisms, referred to as the gut microbiota. Due to their close proximity to human cells, these microorganisms play a crucial role in maintaining the host’s health, influencing various metabolic processes, and providing protection against potentially harmful agents and pathogens. The disruption in this microbial ecosystem, known as dysbiosis, is associated with inflammatory and metabolic diseases, as well as certain types of cancer. Strategies to modulate the microbiota toward a state of homeostasis through the use of “biotics” (probiotics, prebiotics, synbiotics, and postbiotics) have increased. However, challenges such as low stability, loss of microbial viability, and difficulties in delivery to the intestine significantly decrease the progress of their clinical and nutritional applications. Microencapsulation and nanoencapsulation technologies offer potential solutions to enhance the stability, bioavailability, and controlled release of microorganisms and/or bioactive compounds within the gastrointestinal tract. Considering these aspects, this review provides a comprehensive overview of recent advances in nanoencapsulation techniques for biotics, highlighting their mechanisms of action, potential health benefits, and applications in functional foods and targeted therapies. Furthermore, it addresses existing limitations, evaluates feasibility, and discusses the future potential of these technologies in promoting gut health and disease prevention. Further research, especially through clinical studies, is mandatory to verify the safety and effectiveness of nanoencapsulated biotics and to obtain regulatory approval. Full article

Cephus fumipennis, a significant pest of highland spring wheat, damages crops through larval boring and feeding within wheat stalks. This activity disrupts nutrient and water transport, causing severe yield reductions. To find microbial biocontrol agents targeting this pest, primary entomopathogenic microorganisms were isolated and identified from naturally infected, deceased C. fumipennis larvae. Morphological examination and ITS-based phylogenetic analysis tentatively identified the isolate as the entomopathogenic fungus Clonostachys sp. (strain CF01). Third-instar larvae of C. fumipennis were inoculated with conidial suspensions of the CF01 strain at concentrations of 1 × 10⁵, 1 × 10⁶, 1 × 10⁷, and 1 × 10⁸ spores/mL. Spore suspensions of different concentrations demonstrated pathogenicity against third-instar larvae of C. fumipennis. The optimal growth conditions for strain CF01 were identified as follows: PPDA medium, 25 °C, fructose as the carbon source, and yeast extract as the nitrogen source. Photoperiod exhibited no significant effect on either mycelial growth or sporulation. These findings indicate that the CF01 strain possesses considerable potential for the biocontrol of C. fumipennis. Full article

Biofumigation was originally proposed as an alternative to toxic fumigants for the treatment of agricultural soils, owing to the biocidal effect of isothiocyanates (ITCs) released by some plant species like Brassicaceae. However, biofumigation also presents limitations; thus, an advanced and viable alternative could be the use of controlled-release systems such as gelled polymer networks. In the present work, we explore the use of biocompatible hydrogels based on sodium alginate (ALG) and sodium carboxymethylcellulose (CMC), conveniently loaded with a Brassicaceae extract for this purpose. The extract was characterized by means of HPLC-MS, showing its high glucosinolate content, especially glucoraphanin, a secondary metabolite produced by several species of this family. The physicochemical properties of the synthesized gels were investigated by means of differential scanning calorimetry (DSC), rheometry, and scanning electron microscopy (SEM), both in the presence and absence of the loaded extract. Loading and release kinetics (in water) were studied by means of HPLC-DAD, and the Weibull model was employed to interpret the results. It was found that both hydrogels can effectively confine the Brassicaceae extract’s active principle, slowly releasing it in an aqueous environment. Both systems possess excellent properties for real applications, with the CMC-based hydrogels being slightly preferable over the ALG ones due to their higher encapsulation efficiency, mechanical properties, and overall features. These systems are promising tools for combating harmful microorganisms due to the biocidal properties of glucosinolates, but their potential goes beyond their use in agriculture, as they could be applied as antifouling or antimicrobial agents in cultural heritage cleaning or other fields. Full article

Lytic bacteriophages, viruses that attack and kill bacteria cells, can be used in food as biocontrol agents to prevent the growth of pathogenic bacteria. Meat is highly susceptible to bacterial growth, including pathogenic species, the control of which is crucial. Antibiotic use by breeders has resulted in bacterial resistance, which remains a huge problem; bacteriophages have emerged as an interesting alternative. In the literature, the influence of bacteriophages on common foodborne pathogens, such as Salmonella sp., Listeria monocytogenes, Campylobacter jejuni, Yersinia enterocolitica, Escherichia coli, and Shigella sp., has been described. Some phage preparations can show synergistic effects when used with other antimicrobial agents. However, data on the use of bacteriophages to inhibit the growth of meat spoilage bacteria are limited. Bacteriophages can also synthesize endolysins, which possess antimicrobial properties. Contrary to bacteriophages, which are active against only a narrow range of microorganisms (usually one bacterial species), endolysins show a broad spectrum of activity. Full article

Background: Water scarcity is a pressing global challenge increasingly addressed by advanced desalination that converts seawater into potable water. Reverse osmosis and ultrafiltration dominate because they deliver permeate with very low impurities. Their principal limitation is membrane biofouling, which causes clogging, raises energy, operation, and maintenance costs, and shortens membrane life. Multiple approaches mitigate biofouling—most notably pretreatment trains and engineered surface coatings—but cleaning remains the most decisive remediation pathway. Current practice distinguishes physical, chemical, and biological cleaning. Biological cleaning has gained momentum by exploiting microorganisms that inherently counter biofilms. These strategies include targeted secretion of enzymes and antifouling metabolites, and the application of whole-cell culture supernatants containing the full suite of secreted components. In addition, predatory bacteria can infiltrate established biofilms and eradicate them by lysing prey, thereby accelerating the removal of adherent biomass. Progress across these bio-based approaches signals meaningful advances in fouling control and could substantially improve the efficiency, reliability, and sustainability of desalination facilities. Collectively, they underscore the transformative potential of biological antifouling agents in operational systems. Realizing that potential will require rigorous evaluation of technical performance, long-term stability, compatibility with polyamide membranes, regulatory acceptance, and environmental safety, ultimately alongside scalable production and cost-effective deployment in full-scale plants. Full article

Extraintestinal pathogenic Escherichia coli causes community-acquired and nosocomial pneumonia and poses a risk of infection, especially for patients with impaired lung function, such individuals with cystic fibrosis (CF). When chronic infection develops, eradication of the pathogen is difficult even with aggressive antibacterial therapy and targeted CF treatment. A new agent, Fluorthiazinone (CL-55), an inhibitor of bacterial virulence, was registered in Russia in 2024. The aim of our study was to characterize the genomes of E. coli ST648 isolated from long-term-infected CF patients, describe virulence factors, and investigate the effect of CL-55 on two CF isolates in vitro. Comparison of the genomes of hypermucoviscous isolates showed that, in the presence of a large number of core genes, the isolates have adaptive differences both in their chromosomes and the composition and genes of their plasmidomes. Both isolates formed mature biofilms on an abiotic surface and were able to survive and proliferate inside macrophages. CL-55 in in vitro experiments was effective in suppressing E. coli ST648 in both the aggregate and intracellular states, allowing us to propose the use of Fluorthiazinone as a combinative therapy to facilitate eradication of pathogenic microorganisms in the respiratory tract in patients with CF. Full article

The efficient compounding of microbial agents for use in aerobic composting processes is a pressing problem that needs to be addressed. This work focused on the lack of effective oil-degrading microorganisms and the challenges in formulating microbial consortia during the composting of food waste (FW). Following the isolation of three bacteria and three fungi with high oil-degrading ability, a simplex-lattice mixture design methodology was used to conduct compounding within and between groups of bacteria and fungi. Three special cubic response models were successfully developed and validated by performing an analysis of variance. From our analysis, it was demonstrated that the three models had high R² values of 96.06%, 97.18%, and 96.27%. The global solution of the mixture optimization predicted the optimal value for a blend comprising 11.83% Agrobacterium tumefaciens, 8.10% Pseudomonas geniculata, 10.97% Luteibacter rhizovicinus, 20.9% Simplicillium cylindrosporum, 22.3% Fusarium proliferatum, and 25.9% Simplicillium lanosoniveum. Thus, these proportions were considered the optimal combination of strains for oil degradation during FW composting. Composting verification in a 60 L fermenter revealed that the composite microbial agent group had a 31.3% higher oil degradation efficiency than the control group. This work provides valuable insights for the compounding of microbial agents and the resource utilization of rural FW. Full article

The phyllosphere, the aerial part of plants, serves as a crucial habitat for diverse microorganisms. Phyllosphere bacteria can activate protective mechanisms that help plants resist disease. This study focuses on isolating and characterizing phyllosphere bacteria from cucurbits to evaluate their potential in controlling Colletotrichum orbiculare, a pathogen causing anthracnose in cucumbers. Among the 76 bacterial isolates collected, 11 exhibited strong antagonistic effects against C. orbiculare in vitro. Morphological and 16S rRNA analyses identified these isolates as different Bacillus species, including B. vallismortis, B. velezensis, B. amyloliquefaciens, and B. subtilis. These bacteria demonstrated essential plant-growth-promoting and biocontrol traits, such as motility, biofilm formation, phosphate solubilization, nitrogen fixation, and the production of indole acetic acid. Most of the bacterial strains also produced biocontrol compounds such as ammonia, acetoin, siderophores, hydrogen cyanide, chitinase, protease, lipase, and cellulase. The application of these bacteria significantly enhanced cucumber growth in both non-manured and organically manured soils, showing improvements in root and shoot length, chlorophyll content, and biomass accumulation. Additionally, bacterial treatments effectively reduced anthracnose severity, with isolates GL-10 and L-1 showing the highest disease suppression in both soil types. Colonization studies showed that phyllobacteria preferentially colonized healthy leaves over roots and diseased tissues, and they were more effective in manure-amended soils. These results suggest that Bacillus phyllobacteria have strong potential as sustainable bio-stimulants and biocontrol agents, offering an effective approach for enhancing cucumber growth and disease control under both fertilized and unfertilized soil conditions. Full article

Serratia marcescens is a microorganism that exhibits insecticidal activity against various insects, including the migratory fall armyworm (FAW), Spodoptera frugiperda. This article investigates the insecticidal mechanism of S. marcescens through gastric toxicity. The study involved midgut tissue sectioning, hemolymph observation, and microbiome and transcriptome analysis of both infected and uninfected FAW. The findings revealed that S. marcescens effectively disrupted the structure of the midgut, causing midgut shrinkage and rupture, as well as inducing pseudopodia formation in granulocytes. Moreover, it increased the diversity of gut microbiota. Transcriptome analysis indicated an upregulation of metabolic-related genes and tissue repair genes, while there was a downregulation of fat synthesis genes, some immune genes, hormone synthesis genes, etc. The disruption of the midgut structure negatively affects the metabolism and immune function of the FAW, potentially resulting in midgut rupture, systemic sepsis, and ultimately mortality. In conclusion, our study has elucidated the insecticidal mechanism of S. marcescens against the FAW and demonstrated its potential as a biological control agent for managing this pest. Full article

Geraniol (GA) is a terpene compound of natural origin that exhibits strong biological activity. The possibility of using GA as a potential compound with antimicrobial activity is currently of great interest to scientists. The aim of the present study was to comprehensively evaluate the activity of GA against selected strains of Gram-positive bacteria, Gram-negative bacteria, and fungi that pose a significant threat in clinical practice. Among the Gram-positive bacteria studied were Streptococcus spp., Neisseria gonorrhoeae, and Listeria monocytogenes. Among the Gram-negative bacteria tested were Escherichia coli, Pseudomonas aeruginosa, and Klebsiella pneumoniae. The fungal pathogens analyzed included Candida albicans and Candida glabrata. The results showed that GA exhibited strong antimicrobial activity against most of the microorganisms tested. Gram-positive strains were more susceptible to GA compared to Gram-negative strains, probably due to differences in cell wall structure. In the case of fungi, significant efficacy was noted against Candida albicans. This study confirms the potential of GA as an alternative antimicrobial agent, especially against antibiotic-resistant bacterial strains and fungal pathogens. These results open up new perspectives for the application of GA in medicine and the pharmaceutical industry. The study on creams demonstrated that GA possesses strong antimicrobial properties, effectively inhibiting bacterial growth regardless of the concentration used (0.5–12%) and the type of culture medium, confirming its potential as a natural preservative agent in the cosmetic and pharmaceutical industries. Moreover, the research on the anticancer activity of GA revealed its cytotoxic effects against colon cancer cells (LoVo cell line, IC₅₀ = 32.1 μg/mL) and glioma cells (U87 cell line, IC₅₀ = 41.3 μg/mL), particularly at higher concentrations, indicating its promising therapeutic potential. Full article