Effect of fat and lactose supplementation on digestion in dairy cows. 2. Long-chain fatty acids

Dairy cows fitted with rumen and proximal duodenal cannulae were given diets of 60% hay, 7% soybean and rapeseed meal, and either 33% concentrate (control diet) or 33% milk (lipid-supplemented diet: "milk" diet). Amounts of total long-chain fatty acids consumed, entering the duodenum and excreted in the feces were examined. Long-chain fatty acid intake was 192 and 764 g/d with the control and milk diets, respectively. The duodenal flow of long-chain fatty acids was greater (17.3%) than the amount consumed when the control diet was fed; with the milk diet, there was a net loss (-22.2%), mainly due to a decrease in total C16 and C18 acids. The extent of C18:2 hydrogenation in the rumen was reduced by the high fat ration, but for C18:3, hydrogenation was very high and unchanged. Apparent intestinal digestibility of fatty acids was high, especially on the milk diet (86.1%), although the amount of fatty acids absorbed (60.6 g/kg dry matter intake/d) was three times greater than with the control.

Effect of fat and lactose supplementation on digestion in dairy cows. 1. Nonlipid components

Seven cows, of which five were fitted with rumen and duodenal cannulae, alternately received "milk" diet with 10% fat and 13% lactose, and control diet with 2% fat and no lactose. Both diets were 60% hay. Organic matter and crude fiber digestibilities were not different between milk diet (73.4 and 68.1%) and control diet (74.1 and 70.5%). The quantity of organic matter degraded in the rumen (percent of intake) was higher with control diet (51%) than with milk diet (44%). Ratio of duodenal nonammonia nitrogen to nitrogen intake was higher with milk diet. Both diets gave the same rumen pH. The milk diet increased butyrate and minor volatile fatty acids and decreased acetate proportions. The milk diet increased plasma beta-hydroxybutyrate and decreased plasma acetate. These differences were significant only after feeding. Changes in the characteristics of digestion with milk diet were related more to lactose than to fat. No decrease in fiber digestion was seen with the milk diet despite its high fat content.

Helicobacter pylori prevalence in Leipzig's 1998 school entries: methodology and first results

The non-invasive, stable-isotope-aided Helicobacter pylori (H. pylori) tests--breath and equivalent urine tests--were offered on a voluntary basis as part of the mandatory school entry medical examination to the 1998 school entry cohort of the City of Leipzig (480,000 residents). Parents of participating subjects were asked to fill out a detailed epidemiologic questionnaire. The response rate was 94% (n = 2228 of 2369 school starters born in 1991/92). Parent-completed questionnaires were returned by 1890 (80%) children. The overall H. pylori positive prevalence was 7.2%. The prevalence among children with a test and a parent-completed questionnaire was 6.5%. Prevalences among subsequently tested family members of the positive tested children was 65, 60 and 39% for mothers, fathers and siblings respectively. Though studies have shown that the direct transmission of the bacterium (oral-oral and fecal-oral) is a dominant pathway of infection, the questionnaire analyses indicate associations between H. pylori colonisation and living as well as environmental conditions.

Characterization of glycosaminoglycans stored in mucopolysaccharidosis III A: evidence for a generally occuring degradation of heparan sulfate by endoglycosidases

The characterization of intracellularly stored glycosaminoglycans from organs of a patient suffering from mucopolysaccharidosis III A (Sanfilippo A disease) is described. Both heparan sulfate and galactosamine-containing glycosaminoglycans (chondroitin sulfate, dermatan sulfate) are accumulated in the liver, whereas in the other organs (spleen, kidney, heart, cerebrum, cerebellum) heparan sulfate is almost the only glycosaminoglycan stored. It is shown by [3H]NaBH4 reduction and subsequent identification of the 3H-labelled sugar alcohols that heparan sulfate is degraded in all organs by at least two endoglycosidases, an endoglucuronidase and an endoglucosaminidase, to fragments of low molecular weight (Mr approximately 2 000-6 600).

Folding Assessment of Incorporation of Noncanonical Amino Acids Facilitates Expansion of Functional-Group Diversity for Enzyme Engineering

Protein design is limited by the diversity of functional groups provided by the canonical protein „building blocks“. Incorporating noncanonical amino acids (ncAAs) into enzymes enables a dramatic expansion of their catalytic features. For this, quick identification of fully translated and correctly folded variants is decisive. Herein, we report the engineering of the enantioselectivity of an esterase utilizing several ncAAs. Key for the identification of active and soluble protein variants was the use of the split‐GFP method, which is crucial as it allows simple determination of the expression levels of enzyme variants with ncAA incorporations by fluorescence. Several identified variants led to improved enantioselectivity or even inverted enantiopreference in the kinetic resolution of ethyl 3‐phenylbutyrate.

Retinoids Molecular Probes by Late-stage Azide Insertion - Functional Tools to Decrypt Retinoid Metabolism

Studying the complex and intricate retinoids metabolic pathways by chemical biology approaches requires design and synthesis of biologically functional molecular probes. Only few of such molecular retinoid probes could be found in literature, most of them bearing a molecular structure quite different from natural retinoids. To provide close-to-native retinoid probes, we have developed a versatile late-stage method for the insertion of azide function at the C4 position of several retinoids. This one-step process opens straightforward access to different retinoid and carotenoid probes from commercially available precursors. We have further demonstrated that the different molecular probes retain ability of the original compound to activate genes' transcription, despite azide insertion, highlighting biological activities that were further validated in zebrafish in vivo model. The present work paves the way to future studies on vitamin A's metabolism.