Potential Strain Research Articles

Optimization and characterization of bioactive secondary metabolites from Streptomyces sp CMSTAAHL-4 isolated from mangrove sediment

BackgroundTen morphologically different actinomycetes were isolated from mangrove sediments of Manakudy, Kanyakumari District, India. The potent strain was selected based on their primary screening against Gram positive Staphylococcus aureus, Enterococcus faecalis and Gram negative Klebsiella pneumoniae, Escherichia coli, Pseudomonas aeruginosa, Salmonella typhi bacterial pathogens. The selected strain was identified as Streptomyces sp CMSTAAHL-4 by 16S rRNA sequencing. The media optimization for secondary metabolites production was performed by One-Variable at a Time and Response Surface Methodology-Central Composite Design. Minimum inhibitory concentration and minimum bacterial concentration for the extracted secondary metabolites were determined. The antioxidant potential of the secondary metabolites showed that the concentration of the metabolites increases, with the percentage of inhibition. The anti-inflammatory activity of the secondary metabolites found that maximum activity was observed at 500 µg/ml of the metabolites. Alcohols, alkenes, alkynes, alkyl halides, carboxylic acids, aliphatic esters functional groups were identified by fourier transform infrared spectroscopy, gas chromatography and mass spectrometer analysis of the secondary metabolites revealed five bioactive compounds. The X-ray diffraction analysis revealed that the secondary metabolites are amorphous. The thermogravimetric analysis showed the thermal stability of secondary metabolites. Atomic force microscopy analysis revealed specific structural characteristics of the secondary metabolites, which may be associated with their potential biological activities.ConclusionsThe results showed that the antibacterial, antioxidant, and anti-inflammatory chemicals present in the isolated secondary metabolites give them therapeutic properties.

Sustainable biodegradation of malachite green dye by novel non-pathogenic Pseudomonas aeruginosa ED24.

Sustainable management of textile industrial wastewater is one of the severe challenges in the current regime. It has been reported that each year huge amount of textile industry discharge especially the dye released into the environment without pre-treatment that adversely affect the human health and plant productivity. In the present study, different bacterial isolates had been isolated from the industrial effluents and investigated for their bioremediation potential against the malachite green (MG) dye, a major pollutant of textile industries. The biochemical and molecular characterization of the bacterial strain showed the resemblance of most potent strain ED24 as Pseudomonas aeruginosa, which showed effective bioremediation potential against the MG dye. During response surface analysis (RSM), best MG degradation conditions have been observed at pH 7.0, 37°C, 48h, and 200mg/L dye concentration, with highest degradation efficiency of 96.56 ± 0.8622 percent. Subsequently, supplementing various carbon and nitrogen sources increases MG decolorization by 1 to 2%, with beef extract (97.23%), sodium nitrate (97.46%), and maltose (98.67%). FT-IR results revealed the disappearance of distinct peaks, namely, 3328.275cm-1, 2102.842cm-1, 1101.140cm-1,and 559.04cm-1 from MG, and the formation of major intermediate compounds like leucomalachite green, benzoic acid, diacetamide, benzeneacetic acid, hexyl ester, ethyl 4-acetoxy butanoate, butanoic acid, and 2-methyl in GC-MS analysis of degraded dye sample confirms the biodegradation by bacterial strain ED24. The phytotoxicity studies on mung bean seeds confirmed MG dye toxicity reduction up to 67.53%, 54.16%, and 67.53% in biomass accumulation, root, and shoot lengths, respectively. Also, the microbial toxicity of MG was completely reduced on soil microflora Bacillus flexus, Stenotrophomonas maltophilia, Escherichia coli, Staphylococcus aureus, and Alternaria spp.The dual mitigation, both in microbial and plant systems, indicates the strong remediation potential of P. aeruginosa ED24 to break down MG dye ecologically sustainably.

Potent antibacterial and cytotoxic bioactive compounds from endophytic fungi Diaporthe sp. associated with Salacia intermedia.

Antibacterial screening of endophytic fungi from Salacia intermedia identified Diaporthe longicolla as a potent strain exhibiting good activity against multidrug-resistant Staphylococcus aureus and Pseudomonas aeruginosa, with an MIC of 39.1µg/mL. Scale-up fermentation and chromatographic purification of this strain yielded three known compounds, which were cytochalasin J (1), cytochalasin H (2), and dicerandrol C (3), as identified by liquid chromatography - high mass resolution mass spectrometry (LC-HRMS) and nuclear magnetic resonance (NMR) spectroscopy. Among those compounds, dicerandrol C exhibited broad-spectrum antibacterial activity against ATCC and multidrug-resistant strains of Bacillus subtilis, S. aureus, and P. aeruginosa, and multidrug-resistant strains of Klebsiella pneumoniae and Escherichia coli, with MIC values ranging from 1.04 to 33.30 µM. Furthermore, dicerandrol C outperformed tetracycline in antibacterial efficacy against S. aureus ATCC 6538 and methicillin-resistant S. aureus (MRSA) strains (MIC of 1.04 µM). Further antibacterial evaluation showed that cytochalasin J (221.43 µM), cytochalasin H (202.59 µM), and dicerandrol C (tested at its MIC values of 1.04 µM for S. aureus ATCC 6538 and 16.65 µM for P. aeruginosa ATCC 15442) significantly inhibited bacterial biofilm formation. The biofilm inhibition percentages ranged from 61.09 to 78.17% for S. aureus and 41.22-56.83% for P. aeruginosa. In cytotoxicity assays against MCF-7 cells, all three compounds reduced cell viability (48.68-74.50%), with dicerandrol C demonstrating the highest potency. These findings highlight the potential of dicerandrol C as a powerful antibacterial and cytotoxic agent, facilitating further investigations into its therapeutic applications.

Highly Potent New Probiotic Strains from Traditional Turkish Fermented Foods.

Traditional Turkish fermented foods like boza, pickles, and tarhana are recognized for their nutritional and health benefits, yet the probiotic potential of lactic acid bacteria (LAB) strains isolated from them remains underexplored. Sixty-six LAB strains were isolated from fermented foods using bacterial morphology, Gram staining, and catalase activity. The isolates were differentiated at strain level by RAPD-PCR (Random Amplification of Polymorphic DNA-Polymerase Chain Reaction) and twenty-five strains were selected for further evaluation of acid and bile salt tolerance. Among these, ten strains exhibited high tolerance and were subsequently assessed for adhesion to Caco-2 colorectal carcinoma cells, antimicrobial activity, exopolysaccharide (EPS) production, lysozyme resistance, and hemolytic activity. Using k-means clustering, three strains: Lactiplantibacillus plantarum ES-3, Pediococcus pentosaceus N-1, and Enterococcus faecium N-2 demonstrated superior probiotic characteristics, including significant acid (100% survival at pH3.0) and 0.3% bile salt tolerance (57%, 64%, 67%), strong adhesion to intestinal cells (65%, 88%, 91%), high lysozyme resistance (88%, 88%, 77%), and produced high amounts of EPS. These strains show promising potential as probiotics and warrant further investigation to confirm their functional properties and potential applications.

Harnessing algal biomass for sustainable energy: cultivation, strain improvement, and biofuel production.

The world faces pressing environmental challenges, including greenhouse gas emissions, global warming, climate change, and rising sea levels. Alongside, these issues, the depletion of fossil fuels has intensified the search for alternative energy sources. Algal biomass presents a promising long-term solution to these global problems. The quest for sustainable energy has driven significant research into algal biofuels as a viable alternative to fossil fuels. Algae offers several advantages as a feedstock for biofuel production, including high biomass yield, rapid growth rates, cost-effective cultivation, carbon dioxide fixation capabilities, and the potential to grow on non-arable land using non-potable water. This manuscript provides an overview of algal biomass cultivation using renewable feedstocks, identifies potential algal strains for biofuel production, and explores bioengineering advancements in algae. Additionally, strain improvement strategies to enhance biofuel yields are discussed. The review also addresses large-scale algal biomass cultivation for biofuel production, assesses its commercial viability, examines challenges faced by the biofuel industry, and outlines prospects for biofuel production using highly potent algal strains. By overcoming and addressing these challenges, algal biofuels have the potential to become a cornerstone of sustainable energy solutions.

Training healthcare workers and untrained interpreters in remote collaboration amidst COVID-19.

In the context of the public health emergency response to the COVID-19 pandemic in Quebec in 2020, remote public service interpreting has become, within a few days, an essential practice for maintaining services to migrants and allophone refugees, a particularly vulnerable population. This study aimed to measure the impact of two training courses on remote collaboration for mediated consultations developed for healthcare workers and untrained interpreters. A total of 79 healthcare workers and 65 untrained interpreters from the province of Quebec were recruited. They completed the trainings, offered as webinars, and answered the two scales (knowledge and self-efficacy) of the Questionnaire de connaissances sur l'interprétation de service publique à distance [Remote Public Service Interpreting Knowledge Questionnaire]. The study employed paired t-tests to assess the effectiveness of both webinars. Findings reveal a positive impact immediately after completion and at a three-month follow-up. However, there was no significant enhancement in interpreters' self-efficacy over the medium term. Given their modality (remote) and duration (30min for healthcare workers and three hours for interpreters), the training courses are both effective and practical to implement. This study innovatively promotes interprofessional collaboration in public service interpreting and explores online training's potential to enhance both individual and collective efficacy in the field.

The effects of self‐efficacy training on associative memory and brain function in older adults with mild cognitive impairment

AbstractBackgroundOlder adults with mild cognitive impairment (MCI) are known to have declines in cognition greater than that expected for an individual’s age and education level but does not significantly interfere with daily functioning. Memory impairments during the early stages of MCI may predict conversion to Alzheimer’s disease (AD). This impairment can be especially prominent in associative memory – the ability to learn and remember the relationship between two unrelated items. While age‐related memory impairments are often attributed to biological and physiological changes, psychosocial factors could also play a role. A notable psychosocial factor that may affect memory is self‐efficacy – an individual’s confidence in their ability to carry out actions to meet situational or domain‐specific demands. Despite previous research showing a relationship between enhanced self‐efficacy and improved memory performance in older adults, the neural correlates that may explain this relationship remain unclear. Therefore, we developed a six‐week self‐efficacy training intervention to examine its effects on memory and corresponding changes in functional brain activation among older adults with MCI.MethodTwenty‐eight participants were randomized and allocated into either a memory self‐efficacy intervention (n = 14) or general education control group (n = 14). Over six weekly 1.5‐hour group sessions, participants attended either classes that focused on building memory self‐efficacy or general education covering factual and world knowledge. At baseline and endpoint measurements, memory performance and functional brain activation were assessed using an associative memory task during a functional magnetic resonance imaging scan, while memory self‐efficacy was measured with the Multifactorial Memory Questionnaire. Post‐intervention group differences for each outcome measure were analyzed using multiple linear regression models.ResultWe found changes in functional activation patterns during the associative memory task in the memory self‐efficacy training group as a result of the intervention. Specifically, key regions in the brain that are critical for associative memory performance were implicated, suggesting that memory self‐efficacy training can change the way we process and remember information.ConclusionThis study provides insight into how psychosocial factors like self‐efficacy may influence age‐related memory impairments and AD progression, demonstrating self‐efficacy training's potential to enhance memory in at‐risk populations.

Potent human antibodies against SpA5 identified by high-throughput single-cell sequencing of phase I clinical volunteers' B cells.

The drug resistance problem of Staphylococcus aureus needs to be solved urgently. Here, we report the rapid identification of S.aureus human antibodies by high-throughput single-cell RNA and VDJ sequencing of memory B cells derived from 64 volunteers immunized with recombinant five-component S.aureus vaccine (clinical phase I). From 676 antigen-binding IgG1+ clonotypes, TOP10 sequences were selected for expression and characterization, with the most potent one, Abs-9, having nanomolar affinity for the pentameric form of the specific antigen S.aureus protein A. Abs-9 also demonstrated strong prophylactic efficacy in mice injected with lethal doses of a wide range of drug-resistant S.aureus strains. Additionally, the potential epitopes were predicted and validated based on Alphafold2 and molecular docking methods. In all, this study screened for a potent strain of antibody that prevents infection with antibiotic-resistant S.aureus, providing important data to guide the design of vaccines based on antibody architecture.

The therapeutic effect of antioxidant postbiotic cocktail in colitis mice: A promising approach to alleviate oxidative stress in two high-fat and normal-diet feeding mice

It seems that postbiotics as a byproduct of fermentation of probiotic bacteria could be more effective in health benefits context. Therefore, in this study we aimed to assess the effectiveness of a novel postbiotic resulted from native probiotic Lactobacillus strains with robust antioxidant properties in ameliorating colitis in murine models fed with Normal-Diet or High Fat-Diet. Material and methodsEighty-eight strains of Lactobacillus and Bifidobacterium sourced from human feces and milk were screened for antioxidant activity. Six potent strains were selected to formulate a postbiotic cocktail, with its major compounds identified through gas chromatography. ResultsIn an animal study, mice with dextran sulphate sodium (DSS)-induced colitis that received the postbiotic cocktail showed significant improvements in phenotypical indices compared to the DSS group. Mice on both dietary regimens exhibited reduced adverse effects associated with DSS consumption, as indicated by lower Disease Activity Index (DAI) and Pathological Score metrics, along with increased intestinal mass and length(p<0.05). Additionally, mice receiving the postbiotic cocktail demonstrated elevated levels of antioxidant enzymes and anti-inflammatory cytokines(p<0.05). ConclusionThis suggests that the postbiotic not only mitigates inflammation but also enhances antioxidant defenses, particularly in those on a normal diet. Overall, these findings indicate that this novel postbiotic mixture has potential for effectively managing colitis, especially when combined with a healthy dietary regimen, while also highlighting opportunities to optimize environmental factors to enhance its antioxidant capabilities.

Isolation, identification, and characterization of Bacillus subtilis SMP-2 from panitenga and exploring its potential for biosurfactant production

A traditional Assamese fermented food, Panitenga, was explored for potential probiotic isolation. A potent bacterial strain exhibiting biosurfactant production ability was isolated, characterized, and identified as Bacillus subtilis SMP-2. Environmental parameters were optimized for maximum cell growth and biosurfactant production that was found to be pH 6, 30°C, 130 rpm, with glycerol as the carbon (C) source, yeast extract as the nitrogen (N) source, and a C/N ratio of 3:1. At these optimized conditions, the strain yielded 8.13 ± 0.9 g/L of lipopeptide biosurfactant. This biosurfactant remarkably reduced the surface tension of water from 72 mN/m to 37 ± 0.36 mN/m, possessed a low critical micelle concentration (CMC) of 125 mg/L, and exhibited antimicrobial properties. It persisted to be stable across a wide range of physical conditions, including variations in pH, temperature, and salinity. The significantly high production yield and noteworthy properties of the biosurfactant from Bacillus subtilis SMP-2 make it a promising candidate for applications in microbial-enhanced oil recovery (MEOR), bioremediation of oil spills, production of cosmetics and pharmaceuticals, contributing to economic growth and sustainable development.

The effects of cognitive training on driving performance.

Driving is a complex task necessitating an intricate interplay of sensory, motor, and cognitive abilities. Extensive research has underscored the role of neurocognitive functions, including attention, memory, executive functions, and visuospatial skills, in driving safety and performance. Despite evidence suggesting cognitive training's potential in enhancing driving abilities, comprehensive cognitive training's impact on driving performance in young adult drivers remains unexplored. Our study aimed to fill this gap by implementing an intensive, 8-week, multidomain computerized cognitive training program and assessing its transfer effects on the driving performance of young adult drivers, using a high-fidelity simulator. The study employed a randomized controlled trial design, with passive control group. The mixed-design analysis of variance (ANOVA) revealed a notable interaction between the time of testing and the respective participant groups concerning driving performance. Post hoc analyses showed that, compared to the control group, participants undergoing cognitive training demonstrated significantly fewer traffic infractions in the post-training evaluation. These findings suggest that cognitive training could be a useful tool for enhancing driving safety and performance in young adult drivers. Further research should aim to address the limitations posed by the absence of an active control group.

Impact of a Potent Strain of Plant Growth-Promoting Bacteria (PGPB), Bacillus subtilis S1 on Bacterial Community Composition, Enzymatic Activity, and Nitrogen Content in Cucumber Rhizosphere Soils.

Antagonistic bacterial strains from Bacillus spp. have been widely studied and utilized in the biocontrol of phytopathogens and the promotion of plant growth, but their impacts on the rhizosphere microecology when applied to crop plants are unclear. Herein, the effects of applying the antagonistic bacterium Bacillus subtilis S1 as a biofertilizer on the rhizosphere microecology of cucumbers were investigated. In a pot experiment on cucumber seedlings inoculated with S1, 3124 bacterial operational taxonomic units (OTUs) were obtained from the rhizosphere soils using high-throughput sequencing of 16S rRNA gene amplicons, and the most abundant phylum was Proteobacteria that accounted for 49.48% in the bacterial community. S1 treatment significantly reduced the abundances of soil bacterial taxa during a period of approximately 30days but did not affect bacterial diversity in the rhizosphere soils of cucumbers. The enzymatic activities of soil nitrite reductase (S-Nir) and dehydrogenase (S-DHA) were significantly increased after S1 fertilization. However, the activities of soil urease (S-UE), cellulase (S-CL), and sucrase (S-SC) were significantly reduced compared to the control group. Additionally, the ammonium- and nitrate-nitrogen contents of S1-treated soil samples were significantly lower than those of the control group. S1 fertilization reshaped the rhizosphere soil bacterial community of cucumber plants. The S-CL activity and nitrate-nitrogen content in rhizosphere soil affected by S1 inoculation play important roles in altering the abundance of rhizosphere soil microbiota.

Effects of Plant Growth Promoting Halotolerant Pseudomonas Aeruginosa JCM 5962 with Hydrocarbon Degradation Ability, Isolated from Sundarbans Mangrove Area in West Bengal, on Abelmoschus esculentus (Okra) Plant Growth

Plant growth promoting rhizobacteria (PGPR) play a key role in sustainable agricultural practices leading to increased crop productivity. Moreover, PGPR with ability to diminish abiotic stresses like salinity and hydrocarbon contamination in soil, can be developed into potent biofertilizers with maximum ecological benefits. Sundarbans mangrove region in West Bengal, a natural reservoir of diverse microbiota is an important source of PGPR adapted to high salinity and other abiotic stresses like hydrocarbon contamination due to oil spillage and water transport systems, rendering the soil unsuitable for farming. In the present study, a potent PGPR has been isolated from rhizospheric soil of Matla riverbed in mangrove areas of Sundarbans, with simultaneous nitrogen fixing, phosphate solubilizing and plant hormone like indole acetic acid (IAA) producing properties as well as high salt tolerance and hydrocarbon bioremediation abilities. The strain has been identified as Pseudomonas aeruginosa JCM 5962 (NCBI Accession number MK544832.1) on the basis of 16S rRNA analysis. The isolated Pseudomonas aeruginosa strain showed atmospheric nitrogen fixation (3612 ± 2 mg N/ Kg of soil), highest phosphate solubilization index of 3.0 ± 0.06 and 37.14 µg/mL of IAA production. This potent strain also showed salt tolerance upto 7% in culture broth and an uptake of 18.72% of salt. Highest hydrocarbon degradation was shown by this strain in presence of diesel as the sole carbon source. The isolated Pseudomonas aeruginosa strain showed overall improvement in growth of Abelmoschus esculentus (Okra) plants in pot experiments in different conditions like absence of any abiotic stress, presence of 5% salt stress and presence of 1% diesel contaminant. These results indicate that Pseudomonas aeruginosa JCM 5962 can be developed as a potent biofertilizer to be used in agricultural lands of Sundarbans mangrove regions and other areas which are plagued by high salinity and increasing hydrocarbons, particularly petroleum contamination.

Enhancing Growth in Vigna radiata through the Inhibition of Charcoal Rot Disease: A Strategic Approach Using Plant Growth-Promoting Rhizobacteria.

Macrophomina phaseolina is a vital seed and soil-borne phytopathogen responsible for substantial crop yield losses. Although various methods exist for managing soil-borne pathogens, such as agronomic practices, chemical treatments, and varietal tolerance, biological control utilizing plant growth-promoting rhizobacteria (PGPR) or their secondary metabolites presents promising avenues. In this study, a screening of 150 isolates from the rhizosphere of Vigna radiata L. was conducted to identify strains capable of promoting host growth and controlling charcoal rot disease. Among the tested isolates, only 15 strains demonstrated the ability to produce plant growth-related metabolites, including indole acetic acid, hydrogen cyanide, ammonia, and lytic enzymes, and solubilize inorganic phosphate. Subsequently, these potent strains were evaluated for their antifungal activity against Macrophomina phaseolina in vitro. Three strains, namely MRP-7 (58% growth inhibition), MRP-12 (55% growth inhibition), and MRP-8 (44% growth inhibition), exhibited the highest percent growth inhibition (PGI.). Furthermore, a pot experiment demonstrated that the selected strains acted as effective growth promoters and ROS (reactive oxygen species) scavengers, and served as potential biocontrol agents, significantly reducing the incidence of charcoal rot disease and improving various agronomic attributes of the host plant. These findings highlight the potential of these strains to be utilized as biofertilizers and biocontrol agents for sustainable agricultural practices.

Phenazines are involved in the antagonism of a novel subspecies of Pseudomonas chlororaphis strain S1Bt23 against Pythium ultimum

Long-term use of chemical fungicides to control plant diseases caused by fungi and oomycetes has led to pathogen resistance and negative impacts on public health and environment. There is a global search for eco-friendly methods and antagonistic bacteria are emerging as alternatives. We isolated a potent antagonistic bacterial strain (S1Bt23) from woodland soil in Québec, Canada. Taxonomic characterization by 16S rRNA, multi-locus sequence analysis, pairwise whole-genome comparisons, phylogenomics and phenotypic data identified strain S1Bt23 as a novel subspecies within Pseudomonas chlororaphis. In dual culture studies, strain S1Bt23 exhibited potent mycelial growth inhibition (60.2–66.7%) against Pythium ultimum. Furthermore, strain S1Bt23 was able to significantly bioprotect potato tuber slices from the development of necrosis inducible by P. ultimum. Annotations of the whole genome sequence of S1Bt23 revealed the presence of an arsenal of secondary metabolites including the complete phenazine biosynthetic cluster (phzABCDEFG). Thin-layer (TLC) and high-performance liquid (HPLC) chromatographic analyses of S1Bt23 extracts confirmed the production of phenazines, potent antifungal compounds. CRISPR/Cas9-mediated deletion of phzB (S1Bt23ΔphzB) or phzF (S1Bt23ΔphzF) gene abrogated phenazine production based on TLC and HPLC analyses. Also, S1Bt23ΔphzB and S1Bt23ΔphzF mutants lost antagonistic activity and bioprotection ability of potato tubers against P. ultimum. This demonstrated that phenazines are involved in the antagonistic activity of S1Bt23 against P. ultimum. Finally, based on genotypic and phenotypic data, we taxonomically conclude that S1Bt23 represents a novel subspecies for which the name Pseudomonas chlororaphis subsp. phenazini is proposed.

Antimicrobial potential of Streptomyces sp. NP73 isolated from the forest soil of Northeast India against multi-drug resistant Escherichia coli.

This study reports the isolation and characterization of a Streptomyces sp. from soil, capable of producing bioactive secondary metabolites active against a variety of bacterial human pathogens. We targeted the antimicrobial activity against Escherichia coli ATCC-BAA 2469, a clinically relevant strain of bacteria harbouring resistance genes for carbapenems, extended spectrum beta-lactams, tetracyclines, fluoroquinones, etc. Preliminary screening using the spot inoculation technique identified Streptomyces sp. NP73 as the potent strain among the 74 isolated Actinomycetia strain. 16S rRNA gene and whole genome sequencing (WGS) confirmed its taxonomical identity and helped in the construction of the phylogenetic tree. WGS revealed the predicted pathways and biosynthetic gene clusters responsible for producing various types of antibiotics including the isolated compound. Bioactivity guided fractionation and chemical characterization of the active fraction, carried out using liquid chromatography, gas chromatography-mass spectrometry, infra-red spectroscopy, and nuclear magnetic resonance spectroscopy, led to the tentative identification of the active compound as Pyrrolo[1,2-a] pyrazine-1,4-dione, hexahydro-, a diketopiperazine molecule. This compound exhibited excellent antimicrobial and anti-biofilm properties against E. coli ATCC-BAA 2469 with an MIC value of 15.64µg ml-1, and the low cytotoxicity of the compound identified in this study provides hope for future drug development.

Multifaceted and dual-edged native Trichoderma strains from subabul rhizospheric soil to combat Fusarium wilt disease – a sustainable approach

ABSTRACT Fusarium wilt and gummosis disease is a major concern in Subabul plantations, resulting in quantitative and qualitative wood losses to the paper and pulp industry. Growers currently rely on agrochemicals, which are not environmentally safe. Therefore, developing a sustainable control strategy employing biocontrol agents is necessary. For this, the investigation was performed to identify native Trichoderma strains from Subabul rhizospheric soil having antagonistic, disease control efficiency, and PGPR attributes. Six antagonistic Trichoderma (TR1 to TR6) strains were isolated and their efficacy was tested against Fusarium in-vitro by dual plate technique and volatile metabolites. Among these, Trichoderma strains TR1 and TR2 were found efficient in counteracting the growth of F. equiseti (70–90% inhibition) compared to control. The effectiveness was primarily attributed to the increased production of volatile metabolites, siderophores, and the ability to solubilise the nutrients (P and K). Further, six potent Trichoderma strains were identified as T. asperellum (TR1, TR2, TR3, TR6), and T. hamatum (TR4, TR5) through rDNA ITS gene sequencing and phylogenetic analysis. These isolates were mass-multiplied, formulated using Talc powder followed by bio-priming in rooting media. The application of Trichoderma into rooting media reduced the wilt disease caused by artificial inoculation of F. equiseti. Further, TR1 and TR2 were found promising with conferred protection against wilt, enhanced survival rate (10–15%), and improved growth compared to untreated control. Application of adapted TR1 and TR2 antagonists in rooting media during clonal multiplication has the potential wilt control efficiency, enhanced survival rate, and plant growth promotion in Subabul.

Exploring the Potential of Native Urease-Producing Bacteria of Hilly Terrain for Soil Strength Enhancement

Bio-cementation of weathered soils of hilly regions using native ureolytic bacteria is a practical approach to improve soil strength. This study aimed to isolate and characterize native urease-producing bacterial strains from different slope failure regions of Uttarakhand, India, through multi-step screening, and showcased their potential in soil improvement. A total of 80 bacterial strains were isolated from thirteen landslide-prone sites to screen for potent native urease-producing strains. Interestingly, nine native strains exhibited high calcium carbonate precipitation (158–187 mg/10 ml) and urease activity (657–3495 µM/mL) compared to Sporosarcina pasteurii (NCIM 2477), a potent bacterium commonly used for bio-cementation. These strains belonged to various genera, including Lysinibacillus sp., Sporosarcina sp., Pseudochrobactrum sp., and Cytobacillus sp. Cohesionless soil samples treated with the native strains exhibited high unconfined compressive strength values ranging from 0.1 MPa to 1 MPa, whereas those treated with S. pasteurii were 0.15 MPa. The urease-producing bacterial strains with CaCO3 precipitation activity influenced the soil strength and failure patterns. FESEM, XRD, and acid-washing tests revealed that native bacterial strains precipitated CaCO3 more than S. pasteurii strain. The study explores, for the first time, the potential of native ureolytic bacteria from different regions of Uttarakhand, India, for soil strength enhancement.

Optimizing bioethanol production from hassawi rice straw with Aspergillus sp. NAS51 cellulosic enzyme and in silico homology modeling

Researchers' attention has been greatly focused on the use of lignocellulosic wastes to produce bioethanol and biogas due to the depletion of non-renewable energy resources. In our effort to find a potent cellulase-producing fungal strain, the fungus NAS51 was isolated among eight isolates from a sponge collected from the Red Sea, Jeddah, and selected as it displayed the highest cellulase activity including (FP-ase, CMC-ase, and β-glucosidase enzymes) at levels of 3.13 U/ml, 2.52 U/ml, and 0.69 U/ml, respectively. The fungus was identified morphologically and genetically by sequencing its 18SrRNA gene as Aspergillus sp. NAS51. The cellulase activity of Aspergillus sp. NAS51 was optimized and maximum enzyme production was obtained at initial pH7, temp 30oC, incubation period 11 days, moisture content 70%, urea as a nitrogen source, and K2HPO4 (2 g/L). The crude cellulases from strain NAS51 were characterized, and results showed that the enzyme is stable over a wide pH range (6–10), with peak activity at pH 7.0 and 40 °C. The cellulase gene has been sequenced and the protein 3D structure was generated via in silico homology modeling. Determination of binding sites and biological annotations of the constructed protein was carried out via COACH and COFACTOR based on the I-TASSER structure prediction. To reach the maximum enzyme hydrolysis, the rice straw collected from Al-Ahsa, Kingdom of Saudi Arabia was pretreated with NaOH 1.5% to remove lignin and to enhance the saccharification process by Cellulase. The saccharified product was measured using HPLC, fermented by S. cerevisiae and the bioethanol yield produced from the fermentation was 0.454 mL ethanol/g fermentable sugars. This study indicates the potential application of fungal enzymes such as cellulase enzymes in biofuel generation and waste management.

Bioactive compound from marine seagrass Streptomyces argenteolus TMA13: combatting fish pathogens with time-kill kinetics and live-dead cell imaging.

Actinobacteria, pervasive in aquatic and terrestrial environments, exhibit a filamentous morphology, possess DNA with a specific G + C content and production of numerous secondary metabolites. This study, focused on actinobacteria isolated from marine seagrass, investigating their antibacterial activity against fish pathogens. Among 28 isolates, Streptomyces argenteolus TMA13 displayed the maximum zone of inhibition against fish pathogens-Aeromonas hydrophila (10mm), Aeromonas caviae (22mm), Edwardsiella tarda (17mm), Vibrio harveyi (22mm) and Vibrio anguillarum (12mm) using the agar plug method. Optimization of this potent strain involved with various factors, including pH, temperature, carbon source and salt condition to enhance both yield production and antibacterial efficacy. In anti-biofilm assay shows the maximum percentage of inhibition while increasing concentration of TMA13 extract. Minimal Inhibitory Concentration (MIC) and Minimal Bactericidal Concentration (MBC) assays with TMA13 crude extract demonstrated potent activity against fish pathogens at remarkably low concentrations. Time-kill kinetics assay showcased growth curve variations over different time intervals for all fish pathogens treated with a 100µg/ml concentration of crude extract, indicating a decline in cells viability and progression into the death phase. Additionally, fluorescence microscopic visualization of bacterial cells exposed to the extracts emitting green and red fluorescence, enabling live-dead cell differentiation was also studied. Further characterization of the crude extract through GC-MS and FT-IR analyses performed and identified secondary metabolites with functional groups exhibiting significant antibacterial activity. This study elucidates the capacity of Streptomyces argenteolus TMA13 to enhance the production of antibiotic compounds effective against fish pathogens.