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31.
32.
Back Cover: Charge‐Compensated Metallacarborane Building Blocks for Conjugation with Peptides (ChemBioChem 4/2016)
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33.
Monika Haros Nils-Gunnar Carlsson Annette Almgren Marie Larsson-Alminger Ann-Sofie Sandberg Thomas Andlid 《International journal of food microbiology》2009,135(1):7-14
The growing awareness of the relationship between diet and health has led to an increasing demand for food products that support health above and beyond providing basic nutrition. Probiotics are live organisms present in foods, which yield health benefits related to their interactions with the gastrointestinal tract. Phytases are a subgroup of phosphatases that catalyse the desphosphorylation of phytate, which reduces its negative impact on mineral bioavailability, and generates lower inositol phosphates. The aims of this investigation were to (i) study the ability of the probiotic candidate Bifidobacterium pseudocatenulatum to degrade phytate in synthetic medium, to (ii) identify the lower inositol phosphates generated, to (iii) study its survival under conditions mimicking gastrointestinal passage and finally to (iv) assess adhesion of the bacteria to Caco-2 cells. The first steps of InsP6 degradation by B. pseudocatenulatum phytate-degrading enzyme/s were preferentially initiated at the DL-6-position and 5-position of the myo-inositol ring. It suggests that the main InsP6 degradation pathway by B. pseudocatenulatum by sequential removal of phosphate groups was D/L-Ins(1,2,3,4,5)P5 or D/L-Ins(1,2,3,4,6)P5; D/L-Ins(1,2,3,4)P4; to finally Ins(1,2,3)P3 and D/L-Ins(1,2,4)P3/D/L-Ins(1,3,4)P3. This human strain also showed a notable tolerance to bile as well as a selective adhesion capacity (adhesion to control surfaces was zero), to human intestinal Caco-2 cells comparable to the commercial probiotic B. lactis. The phytate-degrading activity constitutes a novel metabolic trait which could contribute to the improvement of mineral absorption in the intestine as a nutritional probiotic feature with potential trophic effect in human gut. 相似文献
34.
Nadja Schulz Oliver Kluth Martin Jastroch Annette Schürmann 《International journal of molecular sciences》2013,14(9):18989-18998
An appropriate insulin secretion by pancreatic beta-cells is necessary to maintain glucose homeostasis. A rise in plasma glucose leads to increased metabolism and an elevated cytoplasmic ATP/ADP ratio that finally triggers insulin granule exocytosis. In addition to this triggering pathway, one or more amplifying pathways—activated by amino acids or fatty acid—enhance secretion by promoting insulin granule recruitment to, and priming at, the plasma membrane. The aim of this study was to clarify the impact of the mitochondrial respiratory activity on fatty acid-induced insulin secretion that was assessed by an extracellular flux analyzer. Treatment of isolated mouse islets with glucose (20 mM) increased insulin secretion 18-fold and correlated with ATP-synthesizing respiration. Furthermore, oxygen consumption rate (OCR) significantly increased by 62% in response to glucose, whereas the addition of palmitate resulted only in a minor increase of OCR at both 2.8 mM (11%) and 20 mM glucose (21%). The addition of palmitate showed a pronounced increase of coupling efficiency (CE) at 2.8 mM glucose but no further insulin secretion. However, treatment with palmitate at 20 mM glucose increased insulin secretion about 32-fold accompanied by a small increase in CE. Thus, fatty acid induced respiration has a minor impact on insulin secretion. Our data clearly demonstrate that fatty acids in contrast to glucose play a minor role for respiration-mediated insulin secretion. In the presence of high glucose, fatty acids contribute partially to amplifying pathways of insulin secretion by further increasing mitochondrial activity in the islets of Langerhans. 相似文献
35.
Rosenwald AG Rhodes MA Van Valkenburgh H Palanivel V Chapman G Boman A Zhang CJ Kahn RA 《Yeast (Chichester, England)》2002,19(12):1039-1056
To examine the functions of the Arf-like protein, Arl1p, in Saccharomyces cerevisiae, a null allele, arl1delta::HIS3, was constructed in two strains. In one background only, loss of ARL1 resulted in temperature-sensitive (ts) growth (suppressed on high-osmolarity media). Allelic variation at the SSD1 locus accounted for differences between strains. Strains lacking ARL1 exhibited several defects in membrane traffic. First, arl1delta strains secreted less protein as measured by TCA-precipitable radioactivity found in the media of [(35)S]-labelled cells. A portion of newly synthesized carboxypeptidase Y (CPY) was secreted rather than correctly targeted to the vacuole. Uptake of the fluid-phase marker, lucifer yellow, was reduced. All these phenotypes were exacerbated in an ssd1 background. The ts phenotype of the arl1deltassd1 strain was suppressed by YPT1, the yeast Rab1a homologue, suggesting that ARL1 and YPT1 have partially overlapping functions. These findings demonstrate that ARL1 encodes a regulator of membrane traffic. 相似文献
36.
Nyström B Becker-Van Slooten K Bérard A Grandjean D Druart JC Leboulanger C 《Water research》2002,36(8):2020-2028
Irgarol 1051 is a recent herbicidal compound, inhibitor of photosynthesis, used in antifouling paints. This toxic is persistent in aquatic environments, with low abiotic and biotic degradation, highly phytotoxic, and has already been detected in estuaries and coastal areas, with suspected negative impacts on non-target organisms (aquatic plants and algae). We measured the toxicity of Irgarol 1051 to macrophytes and phytoplankton from Lake Geneva (between Switzerland and France) by determining chlorophyll fluorescence yield, and phytoplankton primary production. Long-term toxicity for phytoplankton was estimated in a microcosm study, and growth inhibition tests were performed with isolated algal strains. The concentration of Irgarol 1051 was analysed in the water, and the most polluted site showed a higher level (up to 135 ng/L) than the lowest observed effect concentration for phytoplankton (8-80 ng/L), while the macrophytes appeared to be more tolerant to Irgarol 1051 in short-term tests. The microcosm study showed that phytoplankton structure might be even more sensitive to Irgarol 1051. 相似文献
37.
Low Carissa A.; Stanton Annette L.; Danoff-Burg Sharon 《Canadian Metallurgical Quarterly》2006,25(2):181
A randomized trial (n = 60; A. L. Stanton, S. Danoff-Burg, L. A. Sworowski, et al., 2002) revealed that 4 sessions of written expressive disclosure or benefit finding produced lower physical symptom reports and medical appointments for cancer-related morbidities at 3-month follow-up among breast cancer patients relative to a fact-control condition. The goal of this article is to investigate mechanisms underlying these effects. Within-session heart rate habituation mediated effects of expressive disclosure on physical symptoms, and greater use of negative emotion words in essays predicted a decline in physical symptoms. Postwriting mood and use of positive emotion and cognitive mechanism words in essays were not significant mediators, although greater cognitive mechanism word use was related to greater heart rate habituation and negative emotion word use. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
38.
Alfons Weisenburger Kazumi Aoto Annette Heinzel Tomohiro Furukawa 《Journal of Nuclear Materials》2006,358(1):69-76
The behaviour of protective oxide layers on P122 steel and its welds and of ODS steel in liquid Pb44.5Bi55.5 (LBE) is examined under conditions of changing temperatures and oxygen concentrations. P122 (12Cr) and its welded joints are exposed to LBE at 550 °C for 4000 h with oxygen concentrations of 10−6 and 10−8 wt% (p(O2) = 8.1 × 10−23 bar and 5.2 × 10−27 bar) which change every 800 h. It is found that like in case of constant oxygen concentration of 10−6 wt% a protective spinel layer (Fe(Fe1−xCrx)2O4) was maintained on P122 and also on its welded joint. Two experiments with exposure times of 4800 h are conducted on ODS steel, both with temperatures changing from 550 to 650 °C and back every 800 h, one experiment with 10−6 the other with 10−8 wt% oxygen in LBE. Both experiments show strong local dissolution attack after 4800 h which is in agreement with the behaviour of ODS in LBE at a constant temperature of 650 °C. However, dissolution attack is less in LBE with 10−8 wt% oxygen (p(O2) = 3.0 × 10−25 bar). 相似文献
39.
Let G be an embedded planar graph whose edges may be curves. For
two arbitrary points of G, we can compare the length of the
shortest path in G connecting them against their Euclidean
distance. The supremum of all these ratios is called the geometric dilation of G. Given a finite point set, we would
like to know the smallest possible dilation of any graph that
contains the given points. In this paper we prove that a dilation
of 1.678 is always sufficient, and that π/2 = 1.570... is
sometimes necessary in order to accommodate a finite set of
points. 相似文献
40.
Annette C. Feng Apu C. Kapadia Wu-Chun Feng Geneva G. Belford 《The Journal of supercomputing》2002,23(1):51-66
Streaming multimedia with UDP has become increasingly popular over distributed systems like the Internet. Scientific applications that stream multimedia include remote computational steering of visualization data and video-on-demand teleconferencing over the Access Grid. However, UDP does not possess a self-regulating, congestion-control mechanism; and most best-effort traffic is served by congestion-controlled TCP. Consequently, UDP steals bandwidth from TCP such that TCP flows starve for network resources. With the volume of Internet traffic continuing to increase, the perpetuation of UDP-based streaming will cause the Internet to collapse as it did in the mid-1980's due to the use of non-congestion-controlled TCP. To address this problem, we introduce the counter-intuitive notion of inter-packet spacing with control feedback to enable UDP-based applications to perform well in the next-generation Internet and computational grids. When compared with traditional UDP-based streaming, we illustrate that our approach can reduce packet loss over 50% without adversely affecting delivered throughput. 相似文献