Glucose-Induced Biofilm Formation in Bacillus thuringiensis KPWP1 is Associated with Increased Cell Surface Hydrophobicity and Increased Production of Exopolymeric Substances

The Relationship between the Sugar Preference of Bacterial Pathogens and Virulence on Plants

Plant pathogenic bacteria colonize plant surfaces and inner tissues to acquire essential nutrients. Nonstructural sugars hold paramount significance among these nutrients, as they serve as pivotal carbon sources for bacterial sustenance. They obtain sugar from their host by diverting nonstructural carbohydrates en route to the sink or enzymatic breakdown of structural carbohydrates within plant tissues. Despite the prevalence of research in this domain, the area of sugar selectivity and preferences exhibited by plant pathogenic bacteria remains inadequately explored. Within this expository framework, our present review endeavors to elucidate the intricate variations characterizing the distribution of simple sugars within diverse plant tissues, thus influencing the virulence dynamics of plant pathogenic bacteria. Subsequently, we illustrate the apparent significance of comprehending the bacterial preference for specific sugars and sugar alcohols, postulating this insight as a promising avenue to deepen our comprehension of bacterial pathogenicity. This enriched understanding, in turn, stands to catalyze the development of more efficacious strategies for the mitigation of plant diseases instigated by bacterial pathogens.

Biological Mineralization of Methyl Orange by Pseudomonas aeruginosa

Due to its recalcitrant and carcinogenic nature, the presence of methyl orange (MO) in the environment is a serious threat to human and animal life and is also toxic to plants. MO being recalcitrant cannot be effectively reclaimed from industrial effluents through physical and chemical approaches. Biological methods on the other hand have the potential to degrade such dyes because of their compatibility with nature and low chances of adverse effects on the environment. Bacteria, due to their fast growth rate and capability of surviving in extreme environments can effectively be used for this purpose. In the current research study, Pseudomonas aeruginosa was isolated and characterized using 16rRNA from textile wastewater. In the preliminary tests it was found that Pseudomonas aeruginosa has the ability to degrade and mineralize methyl orange effectively. The physicochemical conditions were then optimized, in order to get maximum degradation of MO which was achieved at 37 °C, a pH of 7, a low salt concentration of 0.1 g/15 mL, a high carbon source of 0.6 g/15 mL, and 72 h experimental time. In a single set of experiments where all these optimum conditions were combined, 88.23% decolorization of the selected dye was achieved. At the end of the experimental cycle, the aliquots were homogenized and filtered. The filtrates were subjected to FTIR and GC-MS analysis where azo linkage breaking was confirmed from the FTIR spectra. The filtrates were then extracted with ethyl acetate and then passed through a silica gel column. On the basis of Rf value (TLC plates used) similar fraction were combined which were then subjected to NMR analysis. The compounds detected through GC-MS, peaks were not observed in proton and C-13 NMR. Instead, solvent and some impurity peaks were present, showing that complete mineralization of the dye had occurred due to the action of different bacterial enzymes such as azoreductase, peroxidases, and classes on MO. The prosed mechanism of complete mineralization is based on spectral data that needs to be verified by trapping the individual step products through the use of appropriate inhibitors of individual enzymes.

The RNA Chaperone Protein Hfq Regulates the Characteristic Sporulation and Insecticidal Activity of Bacillus thuringiensis

Bacillus thuringiensis (Bt) is one of the most widely used bio-insecticides at present. It can produce many virulence factors and insecticidal crystal proteins during growth and sporulation. Hfq, on the other hand, is a bacterial RNA chaperone that can regulate the function of different kinds of RNAs, thereby affecting various bacterial phenotypes. To further explore the physiological functions of Hfq in Bt, we took BMB171 as the starting strain, knocked out one, two, or three hfq genes in its genome in different combinations, and compared the phenotypic differences between the deletion mutant strains and the starting strain. We did observe significant changes in several phenotypes, including motility, biofilm formation, sporulation, and insecticidal activity against cotton bollworm, among others. Afterward, we found through transcriptome studies that when all hfq genes were deleted, 32.5% of the genes in Bt were differentially transcribed, with particular changes in the sporulation-related and virulence-related genes. The above data demonstrated that Hfq plays a pivotal role in Bt and can regulate its various physiological functions. Our study on the regulatory mechanism of Hfq in Bt, especially the mining of the regulatory network of its sporulation and insecticidal activity, could lay a theoretical foundation for the better utilization of Bt as an effective insecticide.