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conferenceseries.com
Volume 7, Issue 6 (Suppl) J Bacteriol Parasito
ISSN: 2155-9597 JBP, an open access journal Microbiology 2016
November 28-29, 2016
November 28-29, 2016 Valencia, Spain
7th World Congress on
Microbiology
J Bacteriol Parasitol 2016, 7:6 (Suppl)
Theme and variations in autotransporter adhesins
Begona Heras
La Trobe University, Australia
Many persistent and chronic bacterial infections are associated with the formation of aggregates and biofilms that are difficult
to treat, including respiratory and urinary tract infections (UTIs), infections on medical devices and infections of the ear,
gums and heart. Thus, an increased understanding of the mechanisms employed by bacteria to form biofilms is essential for the
development of strategies to combat these persistent and intrinsically resistant communities. One mechanism of bacterial aggregation
and biofilm formation involves the expression of self-associating surface located autotransporter (AT) proteins. Our work focuses
on investigating the structural diversity of AT proteins to understand their mechanism of action. We have recently elucidated the
structure of Antigen 43 (Ag43), an AT protein from uropathogenic E. coli (UPEC) that self associates forming bacterial aggregates
and biofilms. Our studies have shown how Ag43's L-shaped structure drives the formation of cell aggregates via a molecular Velcro-
like mechanism. Furthermore, our recent studies on other AT proteins from E. coli pathotypes show unexpected structural diversity
among this family of proteins, which results in different virulence functions. For example UpaB shares low sequence and structural
similarity with Ag43, does not self associate to form bacterial aggregates but binds extracellular matrix proteins (e.g., fibronectin) and
increases bladder colonization.
Design and construction of 1,2,4-butanetriol-producing pathway in Escherichia coli
Yanping Zhang, Fan Yang, Lei Sun, Xinghua Li, Taicheng Zhu and Yin Li
Chinese Academy of Sciences, China
1,2,4-butanetriol (BT) is an important non-natural chemical with a variety of industrial applications. Here we constructed a prototype
strain for BT production from xylose by assembling a four-step synthetic pathway and disrupting the competing pathways in E.
coli. By fine-tuning of the pathway enzymes expression level, the potential bottlenecks was identified and the BT production was
increased by 4.3 fold, achieved a final titer of 1.58 g/L after 72 hours. Furthermore, we designed a novel six-step biosynthetic pathway
for BT from malate for the purpose of using glucose as a cheap substrate. Following tests of several combinations of enzymes for
the pathway, a five-enzymes-catalyzing-six-step pathway was constructed in E. coli. By assembling these enzymes, BT was detected
in the fermentation broth upon addition of malate, proving BT can be biosynthesized from malate. As well, BT was detected in the
fermentation using glucose as the sole carbon source, suggesting that such novel BT biosynthetic pathway has created the possibility
for the production of BT from the cheaper substrate glucose.