Molecular characterization of midgut bacteria of Aedes albopictus exhibiting swarming motility property

Abstract

Aedes mosquitoes are responsible for the transmission of arboviruses including dengue, chikungunya, zika, and yellow fever throughout the world. Mosquito gut harbors a variety of microbes, known to play a potential role in various physiological processes such as food digestion and pathogen development. Many bacterial species exert various movements like swarming, gliding and twitching which vary with individual bacterial species. Swarming is one of the movement patterns of bacterial cells in which newly growing cells direct themselves towards the edges of the colony on the solid agar plate. We have isolated a bacterial colony, which exerts swarming activity and moves away from its inoculation point following a translucent path. After repeated sub-culturing of the colony we isolated two different bacterial species which were found to be highly associated to each other in co-culture. Various techniques like biochemical analysis, 16S rRNA gene sequence based analysis, MALDI-TOFF MS and Scanning Electron Microscopy (SEM) were applied for in-depth characterization of isolates. The isolates were identified as Staphylococcus saprophyticus and Brevibacillus agri. Both bacterial isolates showed swarming activity in co-culture on the solid agar surface, but lost the activity when tested individually. Moreover, the swarming activity was even not recovered when both purified bacterial isolates were mixed at different concentrations. This demonstrated that an integral connection exists between the two species which is responsible for their swarming activity in co-culture.

Ion Addition by Electrolysis to Improve the Quantitative Analysis of Bacteria with MALDI-TOF MS

“…Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) is a good choice for accurate and rapid identification of bacterial microorganisms in many fields, such as clinical diagnostics, food safety, and environmental pollution management. − Compared with the commonly plated culture for qualitative detection of bacteria, it can effectively shorten the time consumption and obtain accurate results with the help of some commercial databases . Many studies have successfully applied MALDI-TOF MS in the classification of bacteria based on the results of specific signals at genus, species, or subspecies taxonomic levels. − However, there are no uniform procedures or standard methods for the identification of bacteria, as the operation process and sample pretreatment differences both have an impact on the terminal results. , The uneven distribution of samples caused during the matrix crystallization is the main factor hindering the quantitative identification of bacterial microorganisms.…”