High-Fat Diet Reduces the Formation of Butyrate,but Increases Succinate,Inflammation, Liver Fat and Cholesterol in Rats,while Dietary Fibre Counteracts These Effects

Introduction

Obesity is linked to type 2 diabetes and risk factors associated to the metabolic syndrome. Consumption of dietary fibres has been shown to have positive metabolic health effects, such as by increasing satiety, lowering blood glucose and cholesterol levels. These effects may be associated with short-chain fatty acids (SCFAs), particularly propionic and butyric acids, formed by microbial degradation of dietary fibres in colon, and by their capacity to reduce low-grade inflammation.

Objective

To investigate whether dietary fibres, giving rise to different SCFAs, would affect metabolic risk markers in low-fat and high-fat diets using a model with conventional rats for 2, 4 and 6 weeks.

Material and Methods

Conventional rats were administered low-fat or high-fat diets, for 2, 4 or 6 weeks, supplemented with fermentable dietary fibres, giving rise to different SCFA patterns (pectin – acetic acid; guar gum – propionic acid; or a mixture – butyric acid). At the end of each experimental period, liver fat, cholesterol and triglycerides, serum and caecal SCFAs, plasma cholesterol, and inflammatory cytokines were analysed. The caecal microbiota was analysed after 6 weeks.

Results and Discussion

Fermentable dietary fibre decreased weight gain, liver fat, cholesterol and triglyceride content, and changed the formation of SCFAs. The high-fat diet primarily reduced formation of SCFAs but, after a longer experimental period, the formation of propionic and acetic acids recovered. The concentration of succinic acid in the rats increased in high-fat diets with time, indicating harmful effect of high-fat consumption. The dietary fibre partly counteracted these harmful effects and reduced inflammation. Furthermore, the number of Bacteroides was higher with guar gum, while noticeably that of Akkermansia was highest with the fibre-free diet.     

Growth Monitoring: A Survey of Current Practices of Primary Care Paediatricians in Europe

Objective

We aimed to study current practices in growth monitoring by European primary care paediatricians and to explore their perceived needs in this field.

Methods

We developed a cross-sectional, anonymous on-line survey and contacted primary care paediatricians listed in national directories in the 18 European countries with a confederation of primary care paediatricians. Paediatricians participated in the survey between April and September 2011.

Results

Of the 1,198 paediatricians from 11 European countries (response rate 13%) who participated, 29% used the 2006 World Health Organization Multicentre Growth Reference Study growth charts, 69% used national growth charts; 61% used software to draw growth charts and 79% did not use a formal algorithm to detect abnormal growth on growth charts. Among the 21% of paediatricians who used algorithms, many used non-algorithmic simple thresholds for height and weight and none used the algorithms published in the international literature. In all, 69% of paediatricians declared that a validated algorithm to monitor growth would be useful in daily practice. We found important between-country variations.

Conclusion

The varied growth-monitoring practices declared by primary care paediatricians reveals the need for standardization and evidence-based algorithms to define abnormal growth and the development of software that would use such algorithms.     

Components of metabolic syndrome predicting diabetes: no role of inflammation or dyslipidemia

Objective: The diagnostic criteria and the clinical usefulness of the metabolic syndrome (MetSy) are currently questioned. The objective was to describe the structure of MetSy and to evaluate its components for prediction of diabetes type 2 (T2DM). Research Methods and Procedures: This was a case‐referent study nested within a population‐based health survey. Among 33,336 participants, we identified 177 initially non‐diabetic individuals who developed T2DM after 0.1 to 10.5 years (mean, 5.4 years), and, for each diabetes case, two referents matched for sex, age, and year of health survey. Baseline variables included oral glucose tolerance test, BMI, blood pressure, blood lipids, adipokines, inflammatory markers, insulin resistance, and β‐cell function. Exploratory and confirmative factor analyses were applied to hypothesize the structure of the MetSy. The prediction of T2DM by the different factors was evaluated by multivariate logistic regression analysis. Results: A hypothetical five‐factor model of intercorrelated composite factors was generated. The inflammation, dyslipidemia, and blood pressure factors were predicitive only in univariate analysis. In multivariable analyses, two factors independently and significantly predicted T2DM: an obesity/insulin resistance factor and a glycemia factor. The composite factors did not improve the prediction of T2DM compared with single variables. Among the original variables, fasting glucose, proinsulin, BMI, and blood pressure values were predictive of T2DM. Discussion: Our data support the concept of a MetSy, and we propose five separate clusters of components. The inflammation and dyslipidemia factors were not independently associated with diabetes risk. In contrast, obesity and accompanying insulin resistance and β‐cell decompensation seem to be two core perturbations promoting and predicting progression to T2DM.     

A theoretical study of the<Emphasis Type="Italic"> cis</Emphasis>-dihydroxylation mechanism in naphthalene 1,2-dioxygenase

The catalytic mechanism of naphthalene 1,2-dioxygenase has been investigated by means of hybrid density functional theory. This Rieske-type enzyme, which contains an active site hosting a mononuclear non-heme iron(II) complex, uses dioxygen and two electrons provided by NADH to carry out the cis-dihydroxylation of naphthalene. Since a (hydro)peroxo-iron(III) moiety has been proposed to be involved in the catalytic cycle, it was probed whether and how this species is capable of cis-dihydroxylation of the aromatic substrate. Different oxidation and protonation states of the Fe–O₂ complex were studied on the basis of the crystal structure of the enzyme with oxygen bound side-on to iron. It was found that feasible reaction pathways require a protonated peroxo ligand, Fe^III–OOH; the deprotonated species, the peroxo-iron(III) complex, was found to be inert toward naphthalene. Among the different chemical patterns which have been explored, the most accessible one involves an epoxide intermediate, which may subsequently evolve toward an arene cation, and finally to the cis-diol. The possibility that an iron(V)-oxo species is formed prior to substrate hydroxylation was also examined, but found to implicate a rather high energy barrier. In contrast, a reasonably low barrier might lead to a high-valent iron-oxo species [i.e. iron(IV)-oxo] if a second external electron is supplied to the mononuclear iron center before dioxygenation.Electronic Supplementary Material Supplementary material is available in the online version of this article at http://dx.doi.org/10.1007/s00775-004-0537-0     

Quantitative analysis of tryptic protein mixtures using electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry

For the first time, quantitative analysis of tryptic protein mixtures, labeled with Quantification-Using-Enhanced-Signal-Tags (QUEST)-markers, were performed with electrospray ionization and a 9.4 T Fourier Transform Ion Cyclotron Resonance (FTICR) mass spectrometer. Coupling a High-Pressure Liquid Chromatography (HPLC) separation step prior to mass analysis resulted in an increased amount of identified labeled tryptic peptides. The range for the determined intensity ratios of two peptides in a labeled pair was large, but the obtained median intensity ratio correlated very well with the corresponding concentration ratio. This method can be used for observing protein dynamics in a specific cell type, tissue, or in body fluids.     

Combinatorial synthesis of substituted 3-(2-indolyl)piperidines and 2-phenyl indoles as inhibitors of ZipA-FtsZ interaction

The ZipA-FtsZ protein-protein interaction is a potential target for antibacterial therapy. The design and parallel synthesis of a combinatorial library of small molecules, which target the FtsZ binding area on ZipA are described. Compounds were demonstrated to bind to the FtsZ binding domain of ZipA by HSQC NMR and to inhibit cell division in a cell elongation assay.     

Pea Lectin Expressed Transgenically in Oilseed Rape Reduces Growth Rate of Pollen Beetle Larvae

In several studies plant lectins have shown promise as transgenic resistance factors against various insect pests. We have here shown that pea seed lectin is a potential candidate for use against pollen beetle, a serious pest of Brassica oilseeds. In feeding assays where pollen beetle larvae were fed oilseed rape anthers soaked in a 1% solution of pea lectin there was a reduction in survival of 84% compared to larvae on control treatment and the weight of surviving larvae was reduced by 79%. When a 10% solution of pea lectin was used all larvae were dead after 4 days of testing. To further evaluate the potential use of pea lectin, transgenic plants of oilseed rape (Brassica napus cv. Westar) were produced in which the pea lectin gene under control of the pollen-specific promoter Sta44-4 was introduced. In 11 out of 20 tested plants of the T₀-generation there was a significant reduction in larval weight, which ranged up to 46% compared to the control. A small but significant reduction in larval survival rate was also observed. In the T₂-generation significant weight reductions, with a maximum of 32%, were obtained in 10 out of 33 comparisons between transgenic plants and their controls. Pea lectin concentrations in anthers of transgenic T₂-plants ranged up to 1.5% of total soluble protein. There was a negative correlation between lectin concentration and larval growth. Plants from test groups with significant differences in larval weights had a significantly higher mean pea lectin concentration, 0.64% compared to 0.15% for plants from test groups without effect on larval weight. These results support the conclusion that pea lectin is a promising resistance factor for use in Brassica oilseeds against pollen beetles.     

Identification of a gene cluster in Klebsiella pneumoniae which includes citX, a gene required for biosynthesis of the citrate lyase prosthetic group

The biosynthesis of the 2'-(5"-phosphoribosyl)-3'-dephospho-coenzyme A (CoA) prosthetic group of citrate lyase (EC 4.1.3.6), a key enzyme of citrate fermentation, proceeds via the initial formation of the precursor 2'-(5"-triphosphoribosyl)-3'-dephospho-CoA and subsequent transfer to apo-citrate lyase with removal of pyrophosphate. In Escherichia coli, the two steps are catalyzed by CitG and CitX, respectively, and the corresponding genes are part of the citrate lyase gene cluster, citCDEFXG. In the homologous citCDEFG operon of Klebsiella pneumoniae, citX is missing. A search for K. pneumoniae citX led to the identification of a second genome region involved in citrate fermentation which comprised the citWX genes and the divergent citYZ genes. The citX gene was confirmed to encode holo-citrate lyase synthase, whereas citW was shown to encode a citrate carrier, the third one identified in this species. The citYZ genes were found to encode a two-component system consisting of the sensor kinase CitY and the response regulator CitZ. Remarkably, both proteins showed >or=40% sequence identity to the citrate-sensing CitA-CitB two-component system, which is essential for the induction of the citrate fermentation genes in K. pneumoniae. A citZ insertion mutant was able to grow anaerobically with citrate, indicating that CitZ is not essential for expression of citrate fermentation genes. CitX synthesis was induced to a basal level under anaerobic conditions, independent of citrate, CitB, and CitZ, and to maximal levels during anaerobic growth with citrate as the sole carbon source. Similar to the other citrate fermentation enzymes, CitX synthesis was apparently subject to catabolite repression.