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Other Sugars (other + sugar)
Selected AbstractsMulti-factor regulation of pectate lyase secretion by Colletotrichum gloeosporioides pathogenic on avocado fruitsMOLECULAR PLANT PATHOLOGY, Issue 3 2008I. MIYARA SUMMARY Tissue alkalinization during Colletotrichum gloeosporioides attack enhances the expression of PELB, which encodes pectate lyase (PL), and PL secretion, which is considered essential for full virulence. We studied the regulation of PL secretion by manipulation of C. gloeosporioides PELB. PELB was down-regulated by knocking out PAC1, which encodes the PacC transcription factor that regulates gene products with pH-sensitive activities. We functionally characterized a PACC gene homologue, PAC1, from C. gloeosporioides wild-type (WT) Cg-14 and two independent deletion strains, ,pac1372and ,pac1761. Loss-of-function PAC1 mutants showed 85% reduction of PELB transcript expression, delayed PL secretion and dramatically reduced virulence, as detected in infection assays with avocado fruits. In contrast, PELB was up-regulated in the presence of carbon sources such as glucose. When glucose was used as a carbon source in the medium for the WT strain and the ,pac1 mutant at pH 6.0, PELB transcript expression and PL secretion were activated. Other sugars, such as sucrose and fructose (but not galactose), also activated PELB expression. These results suggest that the pH-regulated response is only part of a multi-factor regulation of PELB, and that sugars are also needed to promote the transition from quiescent to active necrotrophic development by the pathogen. [source] Optimization of culture conditions for glucose oxidase production by a Penicillium chrysogenum SRT 19 strainENGINEERING IN LIFE SCIENCES (ELECTRONIC), Issue 1 2010Ragini G. Bodade Abstract The enzyme glucose oxidase (GOD) has been used for a variety of biotechnological applications in food and pharmaceutical industries. In this study, the optimization of extracellular GOD production was carried out in a Penicillium chrysogenum SRT 19 strain isolated from contaminated and decaying cheese samples. Maximum GOD production was attained at pH 6 and 20°C in fermentation broth after 72,h of incubation. The effects of metal ions and sugars were screened for the induction of higher GOD production. The results revealed that glucose and lactose give the highest production of enzyme (0.670 and 0.552,U/mL, respectively) as compared with other sugars (sucrose, cellulose, mannitol and fructose). Out of the seven metal ions studied, CaCO3 (1.123,U/mL) and FeSO4 (0.822,U/mL) act as modulators, while MgSO4 (0.535,U/mL), CuSO4 (0.498,U/mL), HgCl2 (0.476,U/mL), ZnSO4 (0.457,U/mL) and BaSO4 (0.422,U/mL) yield lower production. The study therefore suggests that a strain of P. chrysogenum SRT 19 can be used as a new strain for GOD production. [source] The Kluyver effect revisitedFEMS YEAST RESEARCH, Issue 4 2003Hiroshi Fukuhara Abstract Yeast species can grow on various sugars. However, in many cases the growth on certain sugars (especially oligosaccharides) occurs only under aerobic conditions, and not in anaerobiosis or in the absence of respiration. Fermentation is blocked under these conditions. This apparent dependence of sugar utilization on the respiration has been called Kluyver effect, and such ,respiration-dependent' species are called Kluyver effect positive. A yeast may be Kluyver effect positive for some sugars and not for others. The physiological meaning and the molecular basis of the phenomenon are not clear. It has recently been reported that Kluyveromyces lactis, which is Kluyver effect positive for galactose and a few other sugars, could be converted into a Kluyver effect-negative form by introduction of relevant sugar transporter genes. Such results offer for the first time a direct support to the hypothesis that the immediate cause of the Kluyver effect may be the low level of sugar transporter activities which is not sufficient to sustain the high substrate flow necessary for fermentative growth, whereas the energy-efficient respiratory growth does not require a high rate of sugar uptake. We examined to what extent this sugar transporter theory of the Kluyver effect can be generalized. [source] STABILITY OF ANTHOCYANINS, PHENOLS AND FREE RADICAL SCAVENGING ACTIVITY THROUGH SUGAR ADDITION DURING FROZEN STORAGE OF BLACKBERRIESJOURNAL OF FOOD PROCESSING AND PRESERVATION, Issue 2009MIRELA KOPJAR ABSTRACT Influence of sugar and mixtures of sugar on color retention of two varieties of blackberries, Thornfree and Cacanska bestrna, were investigated during storage at ,18C for 12 months. After harvest, blackberries were coated with sugars (sucrose, fructose and glucose) and different sugar (sucrose + fructose + glucose, fructose + glucose, fructose + sucrose) mixtures. Anthocynin content, total phenol content and free radical scavenging activity of prepared samples were evaluated. Ratio of fruit : sugar was 1:1. The highest anthocyanin retention was in blackberry samples with glucose addition and the lowest in samples with sucrose addition, in both cultivars. Blackberry samples with sucrose addition had even lower retention than samples without sugar addition. Samples with an addition of other sugars had higher retention of anthocyanin than samples stored without sugars. PRACTICAL APPLICATION Possibility of phenols retention of blackberries due to sugar addition, during cold storage was investigated. Results showed that glucose had the most positive effect on anthocyanins retention as well as total phenolic compounds content. For that reason, certain amount of sucrose in fruit preserves can be replaced by addition of glucose, and for that reason retention of phenolic compounds can be higher and, as could be expected, more effective against oxidative stress in human body due to intake of product formulation with glucose. [source] High glucose levels enhance platelet activation: involvement of multiple mechanismsBRITISH JOURNAL OF HAEMATOLOGY, Issue 3 2006Dzana Sudic Summary Diabetes mellitus (DM) and hyperglycaemia are associated with platelet activation. The present study was designed to investigate how high glucose levels influence platelet function. Fasting human blood was incubated with different concentrations of d -glucose (5, 15 and 30 mmol/l) and other sugars without or with in vitro stimuli. Platelet activation was monitored by whole blood flow cytometry. High glucose levels enhanced adenosine diphosphate (ADP)- and thrombin receptor-activating peptide (TRAP)-induced platelet P-selectin expression, and TRAP-induced platelet fibrinogen binding. Similar effects were seen with 30 mmol/l l -glucose, sucrose and galactose. Hyperglycaemia also increased TRAP-induced platelet-leucocyte aggregation. Protein kinase C (PKC) blockade did not counteract the enhancement of platelet P-selectin expression, but abolished the enhancement of TRAP-induced platelet fibrinogen binding by hyperglycaemia. Superoxide anion scavenging by superoxide dismutase (SOD) attenuated the hyperglycaemic enhancement of platelet P-selectin expression, but did not counteract the enhancement of TRAP-induced platelet fibrinogen binding. Hyperglycaemia did not alter platelet intracellular calcium responses to agonist stimulation. Blockade of cyclo-oxygenase (COX), phosphotidylinositol-3 (PI3) kinase, or nitric oxide synthase, or the addition of insulin did not influence the effect of hyperglycaemia. In conclusion, high glucose levels enhanced platelet reactivity to agonist stimulation through elevated osmolality. This occurred via superoxide anion production, which enhanced platelet P-selectin expression (secretion), and PKC signalling, which enhanced TRAP-induced fibrinogen binding (aggregablity). [source] | ||||||||||