Matthias Schreiner

Prevention of high-fat diet-induced adipose tissue remodeling in obese diabetic mice by n-3 polyunsaturated fatty acids

Objective:Obesity is associated with reduced insulin sensitivity and extensive reorganization of adipose tissue. As polyunsaturated fatty acids (PUFA) appear to inhibit diabetes development, we investigated PUFA effects on markers of matrix remodeling in white adipose tissue.Methods and procedure:Male obese diabetic (db/db) mice were treated with either a low-fat standard diet (LF), or high-fat diets rich in saturated and monounsaturated fatty acids (HF/S), n-6 PUFA (HF/6) or the latter including marine n-3 PUFA (HF/3). White adipose tissue was analyzed for gene expression, fatty acid composition and by immunofluorescence.Results:HF/S treatment increased adipose tissue expression of a number of genes involved in matrix degradation including matrix metalloproteinase (MMP)-12, -14 and cathepsin K, L and S compared with LF. MMP-12 gene was expressed in macrophages and adipocytes, and MMP-12 protein colocalized with both cell types. In addition, mean adipocyte area increased by 1.6-fold in HF/S-treated mice. Genes essential for collagen production, such as procollagen I, III, VI, tenascin C and biglycan were upregulated in HF/S-treated animals as well. N-3 PUFA supplementation resulted in enrichment of these fatty acids in adipose tissue. Moreover, n-3 PUFA inhibited the HF/S-induced upregulation of genes involved in matrix degradation and production I restored mean adipocyte area and prevented MMP-12 expression in macrophages and adipocytes.Conclusion:N-3 PUFA prevent high-fat diet-induced matrix remodeling and adipocyte enlargement in adipose tissue of obese diabetic mice. Such changes could contribute to diabetes prevention by n-3 PUFA in obese patients.

Purification of infective baculoviruses by monoliths

A chromatographic process based on monoliths for purification of infective baculovirus without prior concentration step has been established. Baculovirus produced in Spodoptera frugiperda cells (Sf-9) were harvested by centrifugation, filtered through 0.8 μm filters and directly loaded onto radial 1 mL anion exchange monoliths with a channel size of 1.5-2.0 μm operated at a volumetric flow rate of one bed volume per minute. Optional an epoxy monolith was used as pre-column to reduce interfering compounds and substances influencing the capacity of anion exchange monoliths for baculovirus infectious virus could be eluted with a step gradient at salt concentrations of 440 mM NaCl. Recovery of infectious virus was highly influenced by composition and age of supernatant and ranged from 20 to >99% active baculovirus. Total protein content could be reduced to 1-8% and DNA content to 38-48% in main virus fraction. Infective virus could be 52-fold concentrated within 20.5h and simultaneously an 82-fold volume reduction was possible when loading 1150 mL (2.1×10(8) pfu/mL) onto 1 mL scale support.

Optimization of Solvent Extraction and Direct Transmethylation Methods for the Analysis of Egg Yolk Lipids

The composition of egg yolk lipids differs greatly from most other food lipids, as it combines high contents of triglycerides and phospholipids, as well as a high proportion of cholesterol. The lipids are organized in lipoproteins and are dispersed in aqueous phase. Classical extraction methods using chloroform and methanol have not been optimized for such a matrix, therefore quantitative extraction yields of egg lipids can be inaccurate. In this study, the original method of Bligh and Dyer is evaluated and adapted for egg lipids. Furthermore, a direct extraction/derivatization method is presented. Solvent extraction resulted in a lipid yield of 31.8 ± 0.89% and total fatty acid yield was 257 ± 2 mg/g yolk whereas the direct method yielded 250 ± 7 mg/g yolk. Gas chromatographic analyses confirmed that lipid recovery was complete for triglycerides and phospholipids as well.

Colostrum and milk selenium, antioxidative capacity and immune status of dairy cows fed sodium selenite or selenium yeast

Dietary selenium (Se) can be supplemented from organic or inorganic sources and this may affect Se metabolism and functional outcome such as antioxidative status and immune functions in dairy cows. A feeding trial was performed with 16 Holstein-Friesian dairy cows fed with a total mixed ration (0.18 mg Se/kg dry matter (DM)) either without Se supplement (Control, n = 5), or with Se from sodium selenite (Group SeS, n = 5) or Se yeast (Group SeY, n = 6). In Groups SeS and SeY, the Se supplementation amounted to an additional intake of 4 mg Se and 6 mg Se/d during gestation and lactation, respectively. The effect of both Se sources was characterised by milk Se and antioxidant levels, and the phenotyping and functional assessment of phagocytic activity of milk immune cells. Se yeast has been found to increase (p ≤ 0.001) the milk Se and antioxidant levels markedly compared to the control group. The experimental treatment did not affect the immune parameters of the cows. Lymphocyte subpopulations and phagocytosis activity of neutrophilic granulocytes were affected neither by the Se intake nor by the two different dietary supplements. It can be concluded that sodium selenite and Se yeast differ considerably in their effects on antioxidant status in dairy cows. However, the basal dietary Se concentration of 0.18 mg/kg DM seemed to be high enough for the measured immune variables.

Development and validation of a combined method for the biomonitoring of omega-3/-6 fatty acids and conjugated linoleic acids in different matrices from human and nutritional sources.

Abstract Background: During the last decade, the contribution of omega-3 and -6 long chain-polyunsaturated fatty acids (LC-PUFA) and conjugated linoleic acids (CLA) to the prevention and development of many inflammatory and cardiovascular diseases has been of growing interest. In order to investigate the etiology of these diseases, rapid, combined and comparable methods are invaluable for monitoring both the intake and the incorporation of these fatty acids (FA). Methods: The fatty acid methyl esters (FAME) were analyzed using a gas chromatography/flame ionization detector (GC-FID) system and quantified with an internal standard (C18:0 iso). Results: An effective and rapid protocol for sample preparation and the analysis of FAME was developed and validated. The comparison of different extraction methods showed that the Hara and Radin method gave the best results for serum and erythrocyte membranes. Excellent mean within-day and day-to-day precisions for serum, erythrocytes and cows milk LC-PUFAs demonstrated the high reproduci-bility of the method. Recovery rates for FAMEs in serum and milk were close to 100%. In addition, high mean method linearity (R2) (>0.99) was shown for serum, erythrocytes and cows milk. The sensitivity for FA achieved by GC analysis was acceptable. Conclusion: With the newly adapted protocols, combined and rapid analyses of up to 46 FAMEs, including CLAs and omega-3/-6 LC-PUFAs, can be conducted with high reliability and reproducibility using serum, erythrocyte membranes or cows milk. This provides a novel tool that can be easily implemented in epidemiological studies or clinical diagnostics. Clin Chem Lab Med 2010;48:1757–63.

Prospects for using nonconventional feeds in diets for Awassi dairy sheep in Syria

High feed costs are major obstacles for resource-poor dairy sheep farmers in West Asia, along with large fluctuation in grain and straw prices. Farmers need low-cost diets using locally available feeds that can provide sufficient milk of good quality. Two experimental trials were conducted on Awassi milking ewes to evaluate nonconventional and balanced low-cost diets against the traditional unbalanced diet used by farmers (control) on the total yields (milk, fat, protein, and total solids) and milk composition (fat, protein, total solids, and lactose), an important indicator of milk quality. The first trial was conducted at the research station of the International Center for Agricultural Research in the Dry Areas (ICARDA, Aleppo, Syria) to test 6 low-cost balanced diets using locally available feeds and agro byproducts against the control diet. Each diet was tested on 8 ewes that were kept on pasture as a basal diet, but received different supplements, including barley, wheat bran and nonconventional feeds (urea-treated wheat straw, molasses, sugar beet pulp, and cotton seed cake). Five balanced diets enhanced the total yields of milk, fat, protein, and total solids, in 2 cases, significantly. These diets increased total milk yield by 17.7 to 50.2% and decreased supplement feeding costs by 43% compared with the control. However, milk composition remained unaffected. The second trial was conducted on 3 different farms in northern Syria to assess in each farm a low-cost balanced diet on milking ewes (n=15) in comparison to the farmers control (n=15). The balanced diet was a modification requested by farmers of the best performing diet in the on-station trial. Confirming the first trials research results, the balanced diet outperformed the control in total yields; for instance, it increased total milk yield by 28 to 40% and raised net income by 30%, without affecting milk composition. Both trials showed that using locally available nonconventional feedstuffs, such as molasses, integrated into balanced dairy sheep diets can decrease feed costs of resource-poor farmers, while enhancing total yields of milk and milk constituents without compromising milk quality components. This will greatly improve the profitability of dairy sheep production in dry areas.

Carotenoids and Norisoprenoids as Carotenoid Degradation Products in Pandan Leaves (Pandanus amaryllifolius Roxb.)

Leaves from Pandanus amaryllifolius Roxb., known as pandan leaves, are used as natural colorants, natural flavor, and herbal medicine in Indonesia. These leaves are sources of natural colorants, which are mostly of carotenoid origin. In addition, carotenoids can act as precursors of several aroma impact compounds such as norisoprenoids. The research objective of this study was to determine carotenoids by reversed phase high performance liquid chromatography photo diode array and to determine norisoprenoids by Head Space Solid Phase Micro Extraction Gas Chromatography Mass Spectrophotometry (HS-SPME GC-MS) with the aim to promote pandan leaves as potential natural flavor and natural colorants. β-carotene and lutein were found as major carotenoids in pandan leaves. Three different norisoprenoids (α-ionone, β-ionone, and β-cyclocitral) were identified in pandan leaves along with their carotenoid precursors (α-carotene and β-carotene).

Rapid determination of the various native forms of vitamin B 6 and B 2 in cow’s milk using ultra-high performance liquid chromatography

As the formation of pyridoxal phosphate, the active cofactor of vitamin B6, is dependent on riboflavin 5-phosphate, we propose a fast and simple ultra-high performance liquid chromatography method for the simultaneous determination of the native B6 vitamers pyridoxal, pyridoxine, pyridoxamine, their mono phosphorus esters and 4-pyridoxic acid as well as vitamin B2 as riboflavin and its phosphorus ester riboflavin 5-phosphate in milk. Separation was achieved under 6.0min by reversed-phase and pH gradient elution. Sample preparation was optimized regarding various acids and pH levels. Changes in those parameters led to significant deviations of sample matrix breakdown efficiency. The optimized method was then validated regarding specificity, accuracy, precision, linearity, range, detection and quantification limits. As the method performed satisfactory, is was used to study commercial liquid cows milk (n=31), regarding effects of the employed preservation technique (pasteurization, extended shelf-life, ultra-high temperature) on the composition and content of B6 and B2 vitamers. In cows milk, vitamin B6 mostly consists of pyridoxal and its phosphate ester, with pyridoxal phosphate being the bulk component. The catabolite of the vitamin B6 metabolism, 4-pyridoxic acid was present in significant amounts in all studied samples, with up to 2.69μmolL-1. Vitamin B2 was present as riboflavin and its phosphate ester up to 12.86μmolL-1.

Carotenoid-Cleavage Activities of Crude Enzymes from Pandanous amryllifolius

Carotenoid degradation products, known as norisoprenoids, are aroma‐impact compounds in several plants. Pandan wangi is a common name of the shrub Pandanus amaryllifolius. The genus name ‘Pandanus’ is derived from the Indonesian name of the tree, pandan. In Indonesia, the leaves from the plant are used for several purposes, e.g., as natural colorants and flavor, and as traditional treatments. The aim of this study was to determine the cleavage of β‐carotene and β‐apo‐8′‐carotenal by carotenoid‐cleavage enzymes isolated from pandan leaves, to investigate dependencies of the enzymatic activities on temperature and pH, to determine the enzymatic reaction products by using Headspace Solid Phase Microextraction Gas Chromatography/Mass Spectrophotometry (HS‐SPME GC/MS), and to investigate the influence of heat treatment and addition of crude enzyme on formation of norisoprenoids. Crude enzymes from pandan leaves showed higher activity against β‐carotene than β‐apo‐8′‐carotenal. The optimum temperature of crude enzymes was 70°, while the optimum pH value was 6. We identified β‐ionone as the major volatile reaction product from the incubations of two different carotenoid substrates, β‐carotene and β‐apo‐8′‐carotenal. Several treatments, e.g., heat treatment and addition of crude enzymes in pandan leaves contributed to the norisoprenoid content. Our findings revealed that the crude enzymes from pandan leaves with carotenoid‐cleavage activity might provide a potential application, especially for biocatalysis, in natural‐flavor industry.

Peanut lipids display potential adjuvanticity by triggering a pro-inflammatory response in human keratinocytes

Currently, the earliest cellular and molecular signals driving allergic sensitization to peanuts are not fully understood, even though peanut allergens have been studied extensively. Meanwhile, lipids contained within allergen sources are emerging as players in the pathogenesis of allergies. Exposure of infants to peanut oil-containing lotions was described as a risk factor for the development of peanut allergy (1). This article is protected by copyright. All rights reserved.