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31.
Uyanik F 《Biological trace element research》2001,84(1-3):93-101
The effects of dietary inorganic chromium on some biochemical parameters were determined in lambs fed either a control diet
or a 200-ppb or 400-ppb chromium-supplemented diet. The live weight of the animals were measured and jugular blood samples
were collected prior to supplementation (d 0) and on d 20, 40, and 55. On d 55, three animals from each group were slaughtered
to measure subcutaneous fat. Sera were analyzed for glucose, triglyceride, total cholesterol, high-density lipoprotein (HDL)
and low-density lipoprotein (LDL) cholesterol, total protein, albumin, ALT, AST, and GGT levels. Chromium supplementation
had no significant effect on live weight, but subcutaneous fat was reduced significantly in both chromium groups. There was
a slight decrease in glucose concentrations in the 200-ppb chromium group, although only the differences on d 55 were significant.
Triglyceride levels in both chromium groups were lower than the control group with marked differences in the 400-ppb chromium
group. HDL cholesterol levels increased in both treatment groups compare to control, although the differences in the 400-ppb
chromium group on d 40 were significant. Serum Cr concentrations slightly but not significantly increased in both chromium
groups. No significant differences were found in total and LDL cholesterol, total protein, albumin, ALT, AST, and GGT levels.
In conclusion, chromium supplementation may affect carbohydrate and lipid metabolisms and lipid deposition in lambs. 相似文献
32.
We incorporate a previously validated mathematical model of a vascularized tumor into an optimal control problem to determine
the temporal scheduling of radiotherapy and angiogenic inhibitors that maximizes the control of a primary tumor. Our results
reveal that optimal antiangiogenic monotherapy gives a large initial injection to attain a 20: 1 ratio of tumor cell volume
to supporting vasculature volume. It thereafter maintains this 20: 1 ratio via a continuous dose rate that is intensified
over time. The optimal radiation monotherapy schedule is characterized by amodest dose intensification over time. The best
performance is achieved by our optimal combination regimen, where the antiangiogenic treatment again maintains a constant
tumor-to-vasculature ratio, but is administered in a dose-intensified manner only during the latter portion of the radiation
fractionation schedule. 相似文献
33.
Activation of MAPK homologues by elicitors in tobacco cells 总被引:20,自引:3,他引:17
Angela Lebrun-Garcia Fatma Ouaked Annick Chiltz Alain Pugin 《The Plant journal : for cell and molecular biology》1998,15(6):773-781
Elicitors of plant defence reactions (such as cryptogein, an elicitin produced by Phytophthora cryptogea , or oligogalacturonides (OGs)), induced in tobacco cell suspensions ( Nicotiana tabacum var Xanthi) a rapid and transient activation of two protein kinases (PKs) with apparent molecular masses of 50 and 46 kDa, respectively. These PKs activated and phosphorylated at tyrosine residues, phosphorylated myelin basic protein (MBP) at serine/threonine residues. Both are recognized by anti-MAPK antibodies. The two MBP kinases possessed the same kinetics of activation, and their activation depended, to the same extent, on different exogenously applied compounds (staurosporine, lanthanum, EGTA). We demonstrate here that the activation of the MBP kinases is calcium dependent and sensitive to staurosporine, a protein kinase inhibitor which annihilates all known responses of tobacco cells to cryptogein. The activation of MBP kinases appeared to be independent of the production of active oxygen species (AOS) and insensitive to calyculin A, a protein phosphatase type 1 and 2A inhibitor. The activation of MAPKs is discussed in relation to the early responses induced by cryptogein. 相似文献
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36.
Dina Helmy El-Ghonemy Thanaa Hamed Ali Ahmed Mohamed El-Bondkly Maysa El-Sayed Moharam Fatma Nabeeh Talkhan 《Antonie van Leeuwenhoek》2014,106(5):853-864
Spore suspensions of Aspergillus oryzae NRRL 3484 were subjected to mutagenesis using ultraviolet-irradiation followed by chemical treatments to improve the biosynthesis of cellulase. Ten mutant strains namely UEAC7, UEAR5, UNAC4, UNAC16, UNAR19, UNBC7, UNBR3, UNBR10, UNBR23 and UNBR25 were selected and their extracellular cellulase activities were assayed. Mutant UNAC4 gave the highest cellulase production [2,455 ± 28 U/g-dry substrate (ds) for filter paper-ase (FP-ase)] in a yield 4-fold exceeding that of the wild type strain (578 ± 5.0 U/g-ds for FP-ase). Rice straw (RS) was used as a sole carbon source for the enzyme production at a concentration of 10 % (w/v). Maximum cellulase production was achieved at initial medium pH 5.5, initial moisture content 77 % and an incubation temperature 28 °C on the fifth day of growth. NH4Cl proved to be the suitable added nitrogen source for maximum enzyme production followed by peptone. These results clearly indicate the cost-effectiveness of solid state fermentation technology in the economic production of extracellular cellulase. The hyper-production of cellulase by mutant strain UNAC4 has potential for industrial processes that convert lignocellulosic material (e.g. RS) into products of commercial value such as glucose and biofuels. 相似文献
37.
Fatma Bensassi Ali Rhouma Mohamed Ghrab Hassen Bacha Mohamed Rabeh Hajlaoui 《Mycotoxin Research》2010,26(3):199-203
Aflatoxins (AFs) are potent sources of health risks to both humans and animals. Among them, AFB1 is the most hazardously toxic
and the most frequent in various food commodities, including pistachio nuts. In this survey, the effect of the storage period
on AFB1 accumulation on pistachio nuts was investigated. A total of 49 samples collected during the crop year of 2005 from
the most cultivated pistachio cultivars in Tunisia were rapidly screened by enzyme-linked immunosorbent assay (ELISA) combined
with an immunoaffinity step. The obtained results showed that the contamination of pistachio nuts has occurred clearly after
two years of storage for all the tested cultivars except the case of Mateur variety and Thyna ecotypes. In this study, the
cultivar Mateur was found to be the most susceptible cultivar to contamination by AFB1. After 4 years of storage, the average
contamination levels in nut samples ranged from 2.7 ± 0.3 to 12.7 ± 2.2 μg/kg for AFB1, according to the cultivar. These levels
exceeded the maximum permitted limit of 2 μg/kg set by the European Commission in nuts. 相似文献
38.
Duman F Aksoy A Ozturk F Ceylan A 《Zeitschrift für Naturforschung. C, Journal of biosciences》2010,65(11-12):675-680
Previous studies have shown that salicylates can change the ion permeability of root cells. Therefore the possible effects of exogenous salicylate application on lead (Pb) and copper (Cu) accumulation and its protective role against DNA damage due to metal exposure in Lemna gibba were studied. L. gibba was exposed to 5, 10, and 25 microM Pb and Cu for six days in the presence and absence of sodium salicylate (SA) (0.1, 0.5, and 1 mM). At all concentrations tested, SA application decreased Pb accumulation. On the other hand, application of 0.5 mM SA increased Cu accumulation. SA did not reduce DNA damage resulting from Pb and Cu toxicity. In summary, SA may be useful for reducing Pb accumulation, and application of SA at 0.5 mM may be useful for the phytoextraction of Cu. 相似文献
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