GC/MS based metabolomics: development of a data mining system for metabolite identification by using soft independent modeling of class analogy (SIMCA)

<p>Abstract</p> <p>Background</p> <p>The goal of metabolomics analyses is a comprehensive and systematic understanding of all metabolites in biological samples. Many useful platforms have been developed to achieve this goal. Gas chromatography coupled to mass spectrometry (GC/MS) is a well-established analytical method in metabolomics study, and 200 to 500 peaks are routinely observed with one biological sample. However, only ~100 metabolites can be identified, and the remaining peaks are left as "unknowns".</p> <p>Result</p> <p>We present an algorithm that acquires more extensive metabolite information. Pearson's product-moment correlation coefficient and the Soft Independent Modeling of Class Analogy (SIMCA) method were combined to automatically identify and annotate unknown peaks, which tend to be missed in routine studies that employ manual processing.</p> <p>Conclusions</p> <p>Our data mining system can offer a wealth of metabolite information quickly and easily, and it provides new insights, particularly into food quality evaluation and prediction.</p

Host-Diet Effect on the Metabolism of Bifidobacterium

Bifidobacterium has a diverse host range and shows several beneficial properties to the hosts. Many species should have co-evolved with their hosts, but the phylogeny of Bifidobacterium is dissimilar to that of host animals. The discrepancy could be linked to the niche-specific evolution due to hosts’ dietary carbohydrates. We investigated the relationship between bifidobacteria and their host diet using a comparative genomics approach. Since carbohydrates are the main class of nutrients for bifidobacterial growth, we examined the distribution of carbohydrate-active enzymes, in particular glycoside hydrolases (GHs) that metabolize unique oligosaccharides. When bifidobacterial species are classified by their distribution of GH genes, five groups arose according to their hosts’ feeding behavior. The distribution of GH genes was only weakly associated with the phylogeny of the host animals or with genomic features such as genome size. Thus, the hosts’ dietary pattern is the key determinant of the distribution and evolution of GH genes

Experimental Study on Structural Behaviour of Steel Wire Mesh under Impact Loading

In view of application to debris flow/rockfall barrier system, several types of steel wire mesh were selected to verify their basic behaviour under impact load of free fall weight at the controlled testing environment at an in-house testing facility capable of dropping a heavy weight on approximately 1-meter square panel made of such steel wire mesh material. Out of the 3 types of wire mesh tested, high-performance chain link endured the highest impact load energy, while newly developed wire mesh showed a high potential of effectively absorbing the impact energy by its plastic deformation along the total length of wire components. Both of the above two types of wire mesh are expected to be applied in flexible type debris flow catchment system in combination with larger opening mesh such as ring net. The newly developed wire mesh consisting of spirally deformed steel wires behaved as energy-absorbing elements while transmitting the impact load to the supporting ropes by its own plastic deformation along the total wire length

Prevalence of gastroesophageal reflux disorder in arrhythmic patients and adjunctive effects of proton pump inhibitors on comorbid atrial fibrillation

Background: Although the coexistence of atrial fibrillation (AF) and gastroesophageal reflux disorder (GERD) has been reported, the prevalence of GERD in arrhythmic patients remains unknown. This study aimed to investigate the relationship between GERD and several kinds of arrhythmia, and the therapeutic effects of proton pump inhibitors (PPI) on AF.Methods: In Study 1, patients with various kinds of arrhythmia (n=147) including AF (n=98) were administered a GERD-specific questionnaire (F-scale). In Study 2, patients with AF and GERD (n=27) responded to an AF-specific questionnaire (AFQLQ) before and after the additive PPI therapy to explore the effects of PPI on comorbid AF. In Study 3, device memory was assessed as it is related to PPI administration in pacemaker patients with GERD and AF (n=5) to study the effects of PPI on device-documented AF.Results: Left atrial (LA) size and F-scale scores in AF patients were the largest among the arrhythmic patients in Study 1. Logistic regression analysis showed no independent determinants of GERD. F-scale scores and AFQLQ scores showed temporal and partial correlations and significant improvement after starting PPI in Study 2. However, device interrogation confirmed limited AF improvement by starting PPI in Study 3.Conclusions: GERD is prevalent in AF patients. LA size is not an independent determinant of GERD. Symptoms of AF were improved, whereas device-documented paroxysms of AF were not ameliorated by PPI administration. A large-scale prospective study is required to conclude the efficacy of PPI on the comorbid AF

Amino acid sequence of heat-stable enterotoxin produced by Vibrio cholerae non-01

AbstractThe amino acid sequence of heat-stable enterotoxin, produced by Vibrio cholerae non-01 and isolated from its culture supernatant, was determined by both Edman degradation of native and reductively carboxy-methylated enterotoxin and also a combination of fast atom bombardment mass spectrometry and carboxy-peptidase Y digestion of native enterotoxin to be as follows: Ile-Asp-Cys-Cys-Glu-Ile-Cys-Cys-Asn-Pro-Ala-Cys-Phe-Gly-Cys-Leu-Asn. This sequence is very similar, but not identical, to those of heat-stable enterotoxins produced by enterotoxigenic Escherichia coli and Yersinia enterocolitica