Comparison of Chlamydia antigen and AD-like pathology in the brains of BALB/c mice following intranasal infection with Chlamydia muridarum or Chlamydia pneumoniae

Previous research indicates BALB/c mice inoculated with Chlamydia pneumoniae (Cpn) demonstrated AD-like pathology which suggests that this mouse model is valid for studying the pathogenesis implicated in Alzheimer’s disease (AD). Studies have demonstrated that Chlamydia trachomatis (Ctr) can disseminate from its primary site of infection and plays a major role in the induction of reactive arthritis. The objectives of this lab are: (1) to identify and localize Chlamydia antigens in the brains of BALB/c mice infected with C. muridarum and (2) to determine if infection with C. muridarum induces AD-like pathology comparable to Cpn. Using mouse adapted respiratory isolates of C. muridarum, we investigated whether C. muridarum disseminated from the respiratory tract to the brain. Mice were intranasally infected with plaqued C small Weiss (CSW) or plaqued mouse pneumonitis Weiss (MoPn Weiss). Brain tissue was isolated at 2 months post-infection. Serial sections from brains infected mice were analyzed for amyloid or Chlamydia antigens. Preliminary analysis of brain tissue demonstrated no detectable difference in C. muridarum antigen between mice receiving 1 x105 IFU and mice receiving 1 x101 IFU, whereas a small but detectable difference was identified in amyloid-specific labeling between these two experimental groups. In contrast, prominent Chlamydia-specific labeling was identified in the brains of Cpn-infected mice as well as substantial amyloid deposition at 2 months p.i.. These data suggest that, relative to Cpn AR-39 infection, C. muridarum infection is a weaker stimulus for inflammation, resulting in decreased amyloid deposition in the brains of BALB/c mice

Characterization of the natural variation in Arabidopsis thaliana metabolome by the analysis of metabolic distance

Metabolite fingerprinting is widely used to unravel the chemical characteristics of biological samples. Multivariate data analysis and other statistical tools are subsequently used to analyze and visualize the plasticity of the metabolome and/or the relationship between those samples. However, there are limitations to these approaches for example because of the multi-dimensionality of the data that makes interpretation of the data obtained from untargeted analysis almost impossible for an average human being. These limitations make the biological information that is of prime importance in untargeted studies be partially exploited. Even in the case of full exploitation, current methods for relationship elucidation focus mainly on between groups variation and differences. Therefore, a measure that is capable of exploiting both between- and within-group biological variation would be of great value. Here, we examined the natural variation in the metabolome of nine Arabidopsis thaliana accessions grown under various environmental conditions and established a measure for the metabolic distance between accessions and across environments. This data analysis approach shows that there is just a minor correlation between genetic and metabolic diversity of the nine accessions. On the other hand, it delivers so far in Arabidopsis unexplored chemical information and is shown to be biologically relevant for resistance studies

Stereochemical Insignificance Discovered in Acinetobacter baumannii Quorum Sensing

Stereochemistry is a key aspect of molecular recognition for biological systems. As such, receptors and enzymes are often highly stereospecific, only recognizing one stereoisomer of a ligand. Recently, the quorum sensing signaling molecules used by the nosocomial opportunistic pathogen, Acinetobacter baumannii, were identified, and the primary signaling molecule isolated from this species was N-(3-hydroxydodecanoyl)-l-homoserine lactone. A plethora of bacterial species have been demonstrated to utilize 3-hydroxy-acylhomoserine lactone autoinducers, and in virtually all cases, the (R)-stereoisomer was identified as the natural ligand and exhibited greater autoinducer activity than the corresponding (S)-stereoisomer. Using chemical synthesis and biochemical assays, we have uncovered a case of stereochemical insignificance in A. baumannii and provide a unique example where stereochemistry appears nonessential for acylhomoserine lactone-mediated quorum sensing signaling. Based on previously reported phylogenetic studies, we suggest that A. baumannii has evolutionarily adopted this unique, yet promiscuous quorum sensing system to ensure its survival, particularly in the presence of other proteobacteria

Bioinformatics tools for cancer metabolomics

It is well known that significant metabolic change take place as cells are transformed from normal to malignant. This review focuses on the use of different bioinformatics tools in cancer metabolomics studies. The article begins by describing different metabolomics technologies and data generation techniques. Overview of the data pre-processing techniques is provided and multivariate data analysis techniques are discussed and illustrated with case studies, including principal component analysis, clustering techniques, self-organizing maps, partial least squares, and discriminant function analysis. Also included is a discussion of available software packages