Late acyltransferase genes lpxX and lpxL jointly contribute to the biological activities of Moraxella catarrhalis

Engineering the permeability of Halomonas bluephagenesis enhanced its chassis properties

Bacterial outer membrane (OM), an asymmetric lipid bilayer functioning as a self-protective barrier with reduced permeability for Gram-negative bacteria, yet wasting nutrients and energy to synthesize, has not been studied for its effect on bioproduction. Here we construct several OM-defected halophile Halomonas bluephagenesis strains to investigate the effects of OM on bioproduction. We achieve enhanced chassis properties of H. bluephagenesis based on positive cellular properties among several OM-defected strains. The OM-defected H. bluephagenesis WZY09 demonstrates better adaptation to lower salinity, increasing 28%, 30% and 12% on dry cell mass (DCM), poly(3-hydroxybutyrate) (PHB) accumulation and glucose to PHB conversion rate, respectively, including enlarged cell sizes and 21-folds reduced endotoxin. Interestingly, a poly(3-hydroxybutyrate-co-21mol%4-hydroxybutyrate) (P(3HB-co-21mol%4HB)) is produced by H. bluephagenesis WZY09 derivate WZY249, increasing 60% and 260% on polyhydroxyalkanoate (PHA) production and 4HB content, respectively. Furthermore, increased electroporation efficiency, more sensitive isopropyl β-D-1-thio-galactopyranoside (IPTG) induction, better oxygen uptake, enhanced antibiotics sensitivity and ectoine secretion due to better membrane permeability are observed if OM defected, demonstrating significant OM defection impacts for further metabolic engineering, synthetic biology studies and industrial applications.

Analysis of carbohydrates and glycoconjugates by matrix-assisted laser desorption/ionization mass spectrometry: An update for 2013-2014

This review is the eighth update of the original article published in 1999 on the application of Matrix-assisted laser desorption/ionization mass spectrometry (MALDI) mass spectrometry to the analysis of carbohydrates and glycoconjugates and brings coverage of the literature to the end of 2014. Topics covered in the first part of the review include general aspects such as theory of the MALDI process, matrices, derivatization, MALDI imaging, fragmentation, and arrays. The second part of the review is devoted to applications to various structural types such as oligo- and poly- saccharides, glycoproteins, glycolipids, glycosides, and biopharmaceuticals. Much of this material is presented in tabular form. The third part of the review covers medical and industrial applications of the technique, studies of enzyme reactions, and applications to chemical synthesis. © 2018 Wiley Periodicals, Inc. Mass Spec Rev 37:353-491, 2018.

Panel 6: Vaccines

Objective To review the literature on progress regarding (1) effectiveness of vaccines for prevention of otitis media (OM) and (2) development of vaccine antigens for OM bacterial and viral pathogens. Data Sources PubMed database of the National Library of Science. Review Methods We performed literature searches in PubMed for OM pathogens and candidate vaccine antigens, and we restricted the searches to articles in English that were published between July 2011 and June 2015. Panel members reviewed literature in their area of expertise. Conclusions Pneumococcal conjugate vaccines (PCVs) are somewhat effective for the prevention of pneumococcal OM, recurrent OM, OM visits, and tympanostomy tube insertions. Widespread use of PCVs has been associated with shifts in pneumococcal serotypes and bacterial pathogens associated with OM, diminishing PCV effectiveness against AOM. The 10-valent pneumococcal vaccine containing Haemophilus influenzae protein D (PHiD-CV) is effective for pneumococcal OM, but results from studies describing the potential impact on OM due to H influenzae have been inconsistent. Progress in vaccine development for H influenzae, Moraxella catarrhalis, and OM-associated respiratory viruses has been limited. Additional research is needed to extend vaccine protection to additional pneumococcal serotypes and other otopathogens. There are likely to be licensure challenges for protein-based vaccines, and data on correlates of protection for OM vaccine antigens are urgently needed. Implications for Practice OM continues to be a significant health care burden globally. Prevention is preferable to treatment, and vaccine development remains an important goal. As a polymicrobial disease, OM poses significant but not insurmountable challenges for vaccine development.

Molecular mechanisms of moraxella catarrhalis-induced otitis media

Moraxella catarrhalis is a Gram-negative bacterium, exclusively present in humans and a leading causative agent of otitis media (OM) in children. Most children (80 %) experience at least one episode of OM by their third birthday and half suffer multiple episodes of infection. Over the last 10 years, increased evidence suggests that M. cat possesses multiple virulence factors which can be carried through biologically active outer membrane vesicles (OMVs) that are themselves able to activate host-immune responses. It has also been noted that multiple toll-like receptors are responsible for M. cat recognition. This review is intended to summarize the key findings and progress in recent years of the molecular mechanisms of M. cat-induced otitis media with particular emphasis on adhesion, invasion, and activation of the host immune system, biofilm formation, and vaccine development.