Effects of fructose-containing caloric sweeteners on resting energy expenditure and energy efficiency: a review of human trials.

Epidemiological studies indicate that the consumption of fructose-containing caloric sweeteners (FCCS: mainly sucrose and high-fructose corn syrup) is associated with obesity. The hypothesis that FCCS plays a causal role in the development of obesity however implies that they would impair energy balance to a larger extent than other nutrients, either by increasing food intake, or by decreasing energy expenditure. We therefore reviewed the literature comparing a) diet-induced thermogenesis (DIT) after ingestion of isocaloric FCCS vs glucose meals, and b) basal metabolic rate (BMR) or c) post-prandial energy expenditure after consuming a high FCCS diet for > 3 days vs basal,weight-maintenance low FCCS diet. Nine studies compared the effects of single isocaloric FCCS and glucose meals on DIT; of them, six studies reported that DIT was significantly higher with FCCS than with glucose, 2 reported a non-significant increase with FCCS, and one reported no difference. The higher DIT with fructose than glucose can be explained by the low energy efficiency associated with fructose metabolism. Five studies compared BMR after consumption of a high FCCS vs a low FCCS diet for > 3 days. Four studies reported no change after 4-7 day on a high FCCS diet, and only one study reported a 7% decrease after 12 week on a high FCCS diet. Three studies compared post-prandial EE after consumption of a high FCCS vs a low FCCS diet for > 3 days, and did not report any significant difference. One study compared 24-EE in subjects fed a weight-maintenance diet and hypercaloric diets with 50% excess energy as fructose, sucrose and glucose during 4 days: 24-EE was increased with all 3 hypercaloric diets, but there was no difference between fructose, sucrose and glucose. We conclude that fructose has lower energy efficiency than glucose. Based on available studies, there is presently no hint that dietary FCCS may decrease EE. Larger, well controlled studies are however needed to assess the longer term effects of FCCS on EE.

Total curvature and total torsion of knotted polymers

Previous work on radius of gyration and average crossing number has demonstrated that polymers with fixed topology show a different scaling behavior with respect to these characteristics than polymers with unrestricted topology. Using numerical simulations, we show here that the difference in the scaling behavior between polymers with restricted and unrestricted topology also applies to the total curvature and total torsion. For each knot type, the equilibrium length with respect to a given spatial characteristic is the number of edges at which the value of the characteristic is the same as the average for all polygons. This number appears to be correlated to physical properties of macromolecules, for example gel mobility as measured by the separation between distinct knot types. We also find that, on average, closed polymers require slightly more total curvature and slightly less total torsion than open polymers with the corresponding number of monomers.

Metabolic labeling and protein linearization technology allow the study of proteins secreted by cultured cells in serum-containing media.

Supernatants from cell cultures (also called conditioned media, CMs) are commonly analyzed to study the pool of secreted proteins (secretome). To reduce the exogenous protein background, serum-free media are often used to obtain CMs. Serum deprivation, however, can severely affect cell viability and phenotype, including protein secretion. We present a strategy to analyze the proteins secreted by cells in fetal bovine serum-containing CMs, which combines the advantage of metabolic labeling and protein concentration linearization techniques. Incubation of CMs with a hexapeptide ligand library was used to reduce the dynamic range of the samples and led to the identification of 3 times more proteins than in untreated CM samples. Labeling with a deuterated amino acid was used to distinguish between cellular proteins and homologous bovine proteins contained in the medium. Application of the strategy to two breast cancer cell lines led to the identification of proteins secreted in different amounts and which could correlate with their varying degree of aggressiveness. Selected reaction monitoring (SRM)-based quantitation of three proteins of interest in the crude samples yielded data in good agreement with the results from concentration-equalized samples.

The final N-terminal trimming of a subaminoterminal proline-containing HLA class I-restricted antigenic peptide in the cytosol is mediated by two peptidases.

The proteasome produces MHC class I-restricted antigenic peptides carrying N-terminal extensions, which are trimmed by other peptidases in the cytosol or within the endoplasmic reticulum. In this study, we show that the N-terminal editing of an antigenic peptide with a predicted low TAP affinity can occur in the cytosol. Using proteomics, we identified two cytosolic peptidases, tripeptidyl peptidase II and puromycin-sensitive aminopeptidase, that trimmed the N-terminal extensions of the precursors produced by the proteasome, and led to a transient enrichment of the final antigenic peptide. These peptidases acted either sequentially or redundantly, depending on the extension remaining at the N terminus of the peptides released from the proteasome. Inhibition of these peptidases abolished the CTL-mediated recognition of Ag-expressing cells. Although we observed some proteolytic activity in fractions enriched in endoplasmic reticulum, it could not compensate for the loss of tripeptidyl peptidase II/puromycin-sensitive aminopeptidase activities.

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Plants naturally produce the lipid-derived polyester cutin, which is found in the plant cuticle that is deposited at the outermost extracellular matrix of the epidermis covering nearly all aboveground tissues. Being at the interface between the cell and the external environment, cutin and the cuticle play important roles in the protection of plants from several stresses. A number of enzymes involved in the synthesis of cutin monomers have recently been identified, including several P450s and one acyl-CoA synthetase, thus representing the first steps toward the understanding of polyester formation and, potentially, polyester engineering to improve the tolerance of plants to stresses, such as drought, and for industrial applications. However, numerous processes underlying cutin synthesis, such as a controlled polymerization, still remain elusive. Suberin is a second polyester found in the extracellular matrix, most often synthesized in root tissues and during secondary growth. Similar to cutin, the function of suberin is to seal off the respective tissue to inhibit water loss and contribute to resistance to pathogen attack. Being the main constituent of cork, suberin is a plant polyester that has already been industrially exploited. Genetic engineering may be worth exploring in order to change the polyester properties for either different applications or to increase cork production in other species. Polyhydroxyalkanoates (PHAs) are attractive polyesters of 3-hydroxyacids because of their properties as bioplastics and elastomers. Although PHAs are naturally found in a wide variety of bacteria, biotechnology has aimed at producing these polymers in plants as a source of cheap and renewable biodegradable plastics. Synthesis of PHA containing various monomers has been demonstrated in the cytosol, plastids, and peroxisomes of plants. Several biochemical pathways have been modified in order to achieve this, including the isoprenoid pathway, the fatty acid biosynthetic pathway, and the fatty acid β-oxidation pathway. PHA synthesis has been demonstrated in a number of plants, including monocots and dicots, and up to 40% PHA per gram dry weight has been demonstrated in Arabidopsis thaliana. Despite some successes, production of PHA in crop plants remains a challenging project. PHA synthesis at high level in vegetative tissues, such as leaves, is associated with chlorosis and reduced growth. The challenge for the future is to succeed in synthesis of PHA copolymers with a narrow range of monomer compositions, at levels that do not compromise plant productivity. This goal will undoubtedly require a deeper understanding of plant biochemical pathways and how carbon fluxes through these pathways can be manipulated, areas where plant "omics" can bring very valuable contributions.

Carma1, a CARD-containing binding partner of Bcl10, induces Bcl10 phosphorylation and NF-kappaB activation.

Bcl10, a caspase recruitment domain (CARD)-containing protein identified from a breakpoint in mucosa-associated lymphoid tissue (MALT) B lymphomas, is essential for antigen-receptor-mediated nuclear factor kappaB (NF-kappaB) activation in lymphocytes. We have identified a novel CARD-containing protein and interaction partner of Bcl10, named Carma1. Carma1 is predominantly expressed in lymphocytes and represents a new member of the membrane-associated guanylate kinase family. Carma1 binds Bcl10 via its CARD motif and induces translocation of Bcl10 from the cytoplasm into perinuclear structures. Moreover, expression of Carma1 induces phosphorylation of Bcl10 and activation of the transcription factor NF-kappaB. We propose that Carma1 is a crucial component of a novel Bcl10-dependent signaling pathway in T-cells that leads to the activation of NF-kappaB.

Effects of feed processing on the apparent ileal digestibility of amino acids in pig diets containing wheat bran or wheat middlings

Selostus: Prosessoinnin vaikutus vehnän sivutuotteita sisältävien rehuseosten aminohappojen ohutsuolisulavuuteen sioilla

Fluorine-19 magnetic resonance angiography of the mouse.

PURPOSE: To implement and characterize a fluorine-19 ((19)F) magnetic resonance imaging (MRI) technique and to test the hypothesis that the (19)F MRI signal in steady state after intravenous injection of a perfluoro-15-crown-5 ether (PCE) emulsion may be exploited for angiography in a pre-clinical in vivo animal study. MATERIALS AND METHODS: In vitro at 9.4T, the detection limit of the PCE emulsion at a scan time of 10 min/slice was determined, after which the T(1) and T(2) of PCE in venous blood were measured. Permission from the local animal use committee was obtained for all animal experiments. 12 µl/g of PCE emulsion was intravenously injected in 11 mice. Gradient echo (1)H and (19)F images were obtained at identical anatomical levels. Signal-to-noise (SNR) and contrast-to-noise (CNR) ratios were determined for 33 vessels in both the (19)F and (1)H images, which was followed by vessel tracking to determine the vessel conspicuity for both modalities. RESULTS: In vitro, the detection limit was ∼400 µM, while the (19)F T(1) and T(2) were 1350±40 and 25±2 ms. The (19)F MR angiograms selectively visualized the vasculature (and the liver parenchyma over time) while precisely coregistering with the (1)H images. Due to the lower SNR of (19)F compared to (1)H (17±8 vs. 83±49, p<0.001), the (19)F CNR was also lower at 15±8 vs. 52±35 (p<0.001). Vessel tracking demonstrated a significantly higher vessel sharpness in the (19)F images (66±11 vs. 56±12, p = 0.002). CONCLUSION: (19)F magnetic resonance angiography of intravenously administered perfluorocarbon emulsions is feasible for a selective and exclusive visualization of the vasculature in vivo.

Activation of the mouse TATA-less and human TATA-containing UDP-glucuronosyltransferase 1A1 promoters by hepatocyte nuclear factor 1.

UDP-glucuronosyltransferase (UGT) 1A1 (UGT1A1) catalyzes the glucuronidation of bilirubin in liver. Among all UGT isoforms identified to date, it is the only relevant bilirubin-glucuronidating enzyme in human. Because glucuronoconjugation is the major route of bilirubin elimination, any genetic alteration that affects bilirubin glucuronosyltransferase activity may result in a more or less severe hyperbilirubinemia. In this study, we report the cloning and characterization of the transcriptional regulation of the mouse UGT1A1 gene. Primary-structure analysis of the mouse Thymidine Adevice promoter revealed marked differences with its human homolog. First, the mouse promoter lacks the highly polymorphic thymidine/adenine repeat occurring in the human promoter, which has been associated with some forms of hyperbilirubinemia. Second, an L1 transposon element, which is absent in the human promoter, is found 480 bp upstream of the transcription start site in mouse. Using the electromobility shift and DNase I footprinting experiments, we have identified a hepatocyte nuclear factor 1-binding site in the mouse UGT1A1 promoter that confers responsiveness to both factors HNF1alpha and HNF1beta in HEK293 cells. Furthermore, we show that this element, which is conserved in the human promoter, also confers strong HNF1 responsiveness to the human UGT1A1 gene. Together, these results provide evidence for a major regulatory function of this liver-enriched transcription factor in UGT1A1 activity in both rodents and human.

Soluble MHC-peptide complexes containing long rigid linkers abolish CTL-mediated cytotoxicity.

Soluble MHC-peptide (pMHC) complexes induce intracellular calcium mobilization, diverse phosphorylation events, and death of CD8+ CTL, given that they are at least dimeric and co-engage CD8. By testing dimeric, tetrameric, and octameric pMHC complexes containing spacers of different lengths, we show that their ability to activate CTL decreases as the distance between their subunit MHC complexes increases. Remarkably, pMHC complexes containing long rigid polyproline spacers (&gt; or =80 A) inhibit target cell killing by cloned S14 CTL in a dose- and valence-dependent manner. Long octameric pMHC complexes abolished target cell lysis, even very strong lysis, at nanomolar concentrations. By contrast, an altered peptide ligand antagonist was only weakly inhibitory and only at high concentrations. Long D(b)-gp33 complexes strongly and specifically inhibited the D(b)-restricted lymphocytic choriomeningitis virus CTL response in vitro and in vivo. We show that complications related to transfer of peptide from soluble to cell-associated MHC molecules can be circumvented by using covalent pMHC complexes. Long pMHC complexes efficiently inhibited CTL target cell conjugate formation by interfering with TCR-mediated activation of LFA-1. Such reagents provide a new and powerful means to inhibit Ag-specific CTL responses and hence should be useful to blunt autoimmune disorders such as diabetes type I.

Experimental cerebral malaria develops independently of caspase recruitment domain-containing protein 9 signaling.

The outcome of infection depends on multiple layers of immune regulation, with innate immunity playing a decisive role in shaping protection or pathogenic sequelae of acquired immunity. The contribution of pattern recognition receptors and adaptor molecules in immunity to malaria remains poorly understood. Here, we interrogate the role of the caspase recruitment domain-containing protein 9 (CARD9) signaling pathway in the development of experimental cerebral malaria (ECM) using the murine Plasmodium berghei ANKA infection model. CARD9 expression was upregulated in the brains of infected wild-type (WT) mice, suggesting a potential role for this pathway in ECM pathogenesis. However, P. berghei ANKA-infected Card9(-/-) mice succumbed to neurological signs and presented with disrupted blood-brain barriers similar to WT mice. Furthermore, consistent with the immunological features associated with ECM in WT mice, Card9(-/-) mice revealed (i) elevated levels of proinflammatory responses, (ii) high frequencies of activated T cells, and (iii) CD8(+) T cell arrest in the cerebral microvasculature. We conclude that ECM develops independently of the CARD9 signaling pathway.

Effect of a whey-predominant starter formula containing LCPUFAs and oligosaccharides (FOS/GOS) on gastrointestinal comfort in infants.

Development of new infant formulas aims to replicate the benefits of breast milk. One benefit of breast milk over infant formulas is greater gastrointestinal comfort. We compared indicators of gastrointestinal comfort in infants fed a whey-predominant formula containing long-chain polyunsaturated fatty acids, galacto-oligo-saccharides and fructo-oligosaccharides, and infants fed a control casein-predominant formula without additional ingredients. The single-centre, prospective, double-blind, controlled trial randomly assigned healthy, full-term infants (n=144) to receive exclusively either experimental or control formula from 30 days to 4 months of age. A group of exclusively breast-fed infants served as reference (n=80). At 1, 2, 3, and 4 months, infants' growth parameters were measured and their health assessed. Parents recorded frequency and physical characteristics of infants' stool, frequency of regurgitation, vomiting, crying and colic. At 2-months, gastric emptying (ultrasound) and intestinal transit time (H2 breath test) were measured, and stool samples collected for bacterial analysis. Compared to the control (n=69), fewer of the experimental group (n=67) had hard stools (0.7 vs 7.5%, p<0.001) and more had soft stools (90.8 vs 82.3%, p<0.05). Also compared to the control, the experimental group's stool microbiota composition (mean % bifidobacteria: 78.1 (experimental, n=17), 63.7 (control, n=16), 74.3 (breast-fed, n=20), gastric transit times (59.6 (experimental, n=53), 61.4 (control, n=62), 55.9 (breast-fed, n=67) minutes) and intestinal transit times (data not shown) were closer to that of the breast-fed group. Growth parameter values were similar for all groups. The data suggest that, in infants, the prebiotic-containing whey-based formula provides superior gastrointestinal comfort than a control formula.