Antigenic components of Actinobacillus actinomycetemcomitans lipopolysaccharide recognized by sera from patients with localized juvenile periodontitis

A review of cardiovascular outcomes in the treatment of people with type 2 diabetes

INTRODUCTION

Cardiovascular disease (CVD) is a common and serious complication of type 2 diabetes mellitus (T2DM) often linked to the increased morbidity and mortality associated with T2DM. Monitoring and treating risk factors for CVD are important elements of diabetes management. This review aims to examine CV risk in people with relatively early and mild diabetes who are at substantial risk of CVD; it considers the impact of insulin therapy on this risk by focusing on key studies in patients with diabetes.

METHODS

A literature search was carried out using PubMed to identify key publications, between 2008 and 2013, related to insulin and its possible effect on CVD. This review examines CV risk in diabetes and the impact of insulin therapy on this risk.

RESULTS

Studies have shown that treatment with insulin glargine is associated with marked improvement in the lipid profile of people with T2DM. Intensive insulin therapy has been shown to lower mortality rates in people with diabetes following acute myocardial infarction after 1 year. Retrospective data also indicate that insulin reduces the risk of CVD events, regardless of whether people had comorbidities known to increase CV risk. The prospective ORIGIN (Outcome Reduction with Initial Glargine Intervention) trial found that treatment with insulin glargine had a neutral effect with regard to CV outcomes in people with prediabetes or early diabetes, compared with standard care.

CONCLUSIONS

Other ongoing, large-scale studies of insulin therapy should provide further insights into whether or not insulin therapy can influence long-term CV outcomes.

Genomic Stability of Aggregatibacter actinomycetemcomitans during Persistent Oral Infection in Human

The genome of periodontal pathogen Aggregatibacter actinomycetemcomitans exhibits substantial variations in gene content among unrelated strains primarily due to the presence or absence of genomic islands. This study examined the genomic stability of A. actinomycetemcomitans during its persistent infection in the same host. Four pairs of A. actinomycetemcomitans strains, each pair isolated from an individual over time (0–10 years), were examined for their gains/losses of genes by whole genome sequencing, comparative genomic hybridization by microarray and PCR analysis. Possible effects due to genomic changes were further assessed by comparative transcriptome analysis using microarrays. The results showed that each pair of strains was clonally identical based on phylogenetic analysis of 150 core genes. A novel 24.1-Kb plasmid found in strain S23A was apparently lost in the sibling strain I23C. A 353-bp inversion affecting two essential genes of the serotype-specific gene cluster was found in the serotype antigen-nonexpressing strain I23C, while the same gene cluster was intact in the serotype-expressing sibling strain S23A. A 2,293-bp deletion affecting a gene encoding oxaloacetate decarboxylase and its neighbor region was found in strain SCC2302 but not in the sibling strain AAS4a. However, no evidence of gains or losses of genomic islands was found in the paired strains. Transcriptome profiles showed little or no difference in the paired strains. In conclusion, the genome of A. actinomycetemcomitans appears to be relatively stable during short-term infection. Several types of genomic changes were observed in the paired strains of A. actinomycetemcomitans recovered from the same subjects, including a mutation in serotype-specific gene cluster that may allow the bacteria to evade host immune response.

Identification of an ATP-binding cassette transporter for export of the O-antigen across the inner membrane in Rhizobium etli based on the genetic, functional, and structural analysis of an lps mutant deficient in O-antigen

For O-antigen lipopolysaccharide (LPS) synthesis in bacteria, transmembrane migration of undecaprenyl pyrophosphate-bound O-antigen oligosaccharide subunits or polysaccharide occurs before ligation to the core region of the LPS molecule. In this study, we identified by mutagenesis an ATP-binding cassette transporter in Rhizobium etli CE3 that is likely responsible for the translocation of the O-antigen across the inner plasma membrane. Mutant FAJ1200 LPS lacks largely the O-antigen, as shown by SDS-polyacrylamide gel electrophoresis and confirmed by immunoblot analysis. Furthermore, LPS isolated from FAJ1200 is totally devoid of any O-chain glycosyl residues and contains only those glycosyl residues that can be expected for the inner core region. The membrane component and the cytoplasmic ATP-binding component of the ATP-binding cassette transporter are encoded by wzm and wzt, respectively. The Tn5 transposon in mutant FAJ1200 is inserted in the wzm gene. This mutation resulted in an Inf- phenotype in bean plants.