Screening and identification of a Bacillus thuringiensis strain S1/4 with large and efficient insecticidal activities

The bacterium Bacillus thuringiensis was recognized for its entomopathogenic activities related to Cry and Cyt proteins forming the δ-endotoxins and some extracellular activities like the vegetative insecticidal proteins (VIP) and Cry1I. These activities may act specifically against diverse organisms and some of them typically characterize each strain. Here, we screened a set of 212 B. thuringiensis strains to search the higher insecticidal activities. These strains had bipyramidal and cubic crystal morphologies and 30% of them showed PCR amplification of vip3 internal region, from which five isolates (S1/4, S17, S122, S123, and S144) showed plasmid profile variability. These five strains contained the cry1I, cry1Aa and/or cry1Ac, cry1Ab and cry2 genes, and S1/4 harbored in addition the cry1C, vip1, and vip2 genes. They produced from 25 to 46 µg δ-endotoxin per 10(7) spores. Their δ-endotoxins displayed distinct lethal concentrations 50% against either Spodoptera littoralis or Ephestia kuehniella larvae with the lowest one for S1/4, which was also active against Tuta absoluta. Fortunately, the analysis of the culture supernatants revealed that S1/4 had the higher toxicity towards these lepidopteron but it did not show any toxicity against the Tribolium castaneum coleopteran larvae; additionally, S1/4 displayed an antibacterial activity. S1/4 is a good candidate for agricultural pest control, as it is more efficient than the reference strain HD1.

Bacillus amyloliquefaciens: Harnessing Its Potential for Industrial, Medical, and Agricultural Applications-A Comprehensive Review

Bacillus amyloliquefaciens, a Gram-positive bacterium, has emerged as a versatile microorganism with significant applications in various fields, including industry, medicine, and agriculture. This comprehensive review aims to provide an in-depth understanding of the characteristics, genetic tools, and metabolic capabilities of B. amyloliquefaciens, while highlighting its potential as a chassis cell for synthetic biology, metabolic engineering, and protein expression. We discuss the bacterium's role in the production of chemicals, enzymes, and other industrial bioproducts, as well as its applications in medicine, such as combating infectious diseases and promoting gut health. In agriculture, B. amyloliquefaciens has demonstrated potential as a biofertilizer, biocontrol agent, and stress tolerance enhancer for various crops. Despite its numerous promising applications, B. amyloliquefaciens remains less studied than its Gram-negative counterpart, Escherichia coli. This review emphasizes the need for further research and development of advanced engineering techniques and genetic editing technologies tailored for B. amyloliquefaciens, ultimately unlocking its full potential in scientific and industrial contexts.

Optimization of Bacillus amyloliquefaciens BLB369 Culture Medium by Response Surface Methodology for Low Cost Production of Antifungal Activity

Bacillus amyloliquefaciens BLB369 is an important plant growth-promoting bacterium, which produces antifungal compounds. A statistics-based experimental design was used to optimize a liquid culture medium using inexpensive substrates for increasing its antifungal activity. A Plackett–Burman design was first applied to elucidate medium components having significant effects on antifungal production. Then the steepest ascent method was employed to approach the experimental design space, followed by an application of central composite design. Three factors were retained (candy waste, peptone, and sodium chloride), and polynomial and original trigonometric models fitted the antifungal activity. The trigonometric model ensured a better fit. The contour and surface plots showed concentric increasing levels pointing out an optimized activity. Hence, the polynomial and trigonometric models showed a maximal antifungal activity of 251.9 (AU/mL) and 255.5 (AU/mL) for (19.17, 19.88, 3.75) (g/L) and (19.61, 20, 3.7) (g/L) of candy waste, peptone, and NaCl, respectively. This study provides a potential strategy for improving the fermentation of B. amyloliquefaciens BLB369 in low-cost media for large-scale industrial production.

The Gut Microbiota and Colorectal Cancer: Understanding the Link and Exploring Therapeutic Interventions

CRC remains a significant public health challenge due to its high prevalence and mortality rates. Emerging evidence highlights the critical role of the gut microbiota in both the pathogenesis of CRC and the efficacy of treatment strategies, including chemotherapy and immunotherapy. Dysbiosis, characterized by imbalances in microbial communities, has been implicated in CRC progression and therapeutic outcomes. This review examines the intricate relationship between gut microbiota composition and CRC, emphasizing the potential for microbial profiles to serve as biomarkers for early detection and prognosis. Various interventions, such as prebiotics, probiotics, postbiotics, fecal microbiota transplantation, and dietary modifications, aim to restore microbiota balance and shift dysbiosis toward eubiosis, thereby improving health outcomes. Additionally, the integration of microbial profiling into clinical practice could enhance diagnostic capabilities and personalize treatment strategies, advancing the field of oncology. The study of intratumoral microbiota offers new diagnostic and prognostic tools that, combined with artificial intelligence algorithms, could predict treatment responses and assess the risk of adverse effects. Given the growing understanding of the gut microbiome-cancer axis, developing microbiota-oriented strategies for CRC prevention and treatment holds promise for improving patient care and clinical outcomes.