A cytosol derived factor of Group B streptococcus prevent its invasion into human epithelial cells

Abstract

Group B streptococcus (GBS) or Streptococcus agalactiae, is an opportunistic pathogen causing a wide range of infections like pneumonia, sepsis, and meningitis in newborn, pregnant women and adults. While this bacterium has adapted well to asymptomatic colonization of adult humans, it still remains a potentially devastating pathogen to susceptible infants. Advances in molecular techniques and refinement of in vitro and in vivo model systems have elucidated key elements of the pathogenic process, from initial attachment to the maternal vaginal epithelium to penetration of the newborn blood-brain barrier. Still, the formidable array of GBS virulence factors makes this bacterium at the forefront of neonatal pathogens. The involvement of bacterial components in the host-pathogen interaction of GBS pathogenesis and its related diseases is not clearly understood. In this study we demonstrated the role of a 39 kDa factor from GBS which plays an important role in the process of its invasion. We found a homogeneous 39 kDa factor from the cytosol of GBS after following a combination of sequential purification steps involving molecular sieving and ion exchange chromatography using ACTA-FPLC system. Its N-terminal sequence showed a homology with xenobiotic response element type transcriptional regulator protein, a 40 kDa protein of Streptococcus. This factor leads to inhibition of GBS invasion in HeLa and A549 cells. This protein also showed sensitivity and specific cross reactivity with the antibodies raised against it in New Zealand white rabbits by western immunoblotting. This inhibitory factor was further confirmed tolerant for its cytotoxicity. These results add a novel aspect to bacterial pathogenesis where bacteria's own intracellular protein component can act as a potential therapeutic candidate by decreasing the severity of disease thus promoting its invasion inhibition.

A Microbiome Study Reveals Seasonal Variation in Endophytic Bacteria Among different Mulberry Cultivars

“…Seasonal variations in the endophyte community could be attributed to the optimal temperature for microbial growth or the changing physiology of the deciduous trees [48]. Wang et al [26] reported that the succession of microbial communities that occurs in plants during the growing season can be explained by two potential mechanisms, the first of which is related to temporal changes in abiotic conditions such as moisture and temperature, and the second is the changes that occur in plant tissue exudates and photosynthetic products over the course of the growing season.…”

“…Furthermore, array of studies have documented that climate, moisture, and temperature are important environmental properties that influence the population density and ecology of the microbial community [[23], [24], [25]]. For example, the effect of the temperature sensitivity on microbial respiration was reported to be season-dependent, being much greater in the dormant season than in the growing season [26]. Similarly, seasonal changes in the concentration of soluble sugars, proteins, amino acids, organic acids, and other plant nutrients also affect microbial communities.…”

Cell Surface and Cytosolic Proteins of Group B Streptococcus Adding New Dimensions in Its Colonization and Pathogenesis

“…There are many other studies which report that cell surface molecules can also be used to inhibit adherence and invasion in bacteria. A recent published study Cell Surface and Cytosolic Proteins of Group B Streptococcus Adding New Dimensions… DOI: http://dx.doi.org /10.5772/intechopen.89102 from our lab has reported the role of a cytosolic protein in inhibition of invasion of GBS into eukaryotic epithelial cells [34]. A 39 kDa invasion inhibitory factor (IIF) isolated from cytosol of GBS showed almost 70-80% reduction in invasion as compared to the crude cytosolic fractions indicating an anti-internalization mechanism.…”