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81.
Vivien Krell Desirée Jakobs-Schoenwandt Marcus Persicke Anant V. Patel 《World journal of microbiology & biotechnology》2018,34(8):108
Successful commercialization of microbial biocontrol agents, such as Metarhizium spp., is often constrained by poor drying survival and shelf life. Here, we hypothesized that culture age would influence endogenous arabitol, erythritol, mannitol and trehalose contents in M. brunneum mycelium and that elevated levels of these compounds would improve drying survival and shelf life of encapsulated mycelium coupled with enhanced fungal virulence against T. molitor larvae. We found that culture age significantly influenced endogenous arabitol and mannitol contents in mycelium with highest concentrations of 0.6?±?0.2 and 2.1?±?0.2 µg/mg after 72 h, respectively. Drying survival of encapsulated mycelium was independent of culture age and polyol content with 41.1?±?4.4 to 55.0?±?6.2%. Best shelf life was determined for biomass harvested after 72 h at all investigated storage temperatures with maximum values of 59.5?±?3.3% at 5 °C followed by 54.5?±?1.6% at 18 °C and 19.4?±?1.3% at 25 °C after 6 months. Finally, high fungal virulence against T. molitor larvae of 83.3?±?7.6 to 98.0?±?1.8% was maintained during storage of encapsulated mycelium for 12 months with larval mortalities being independent of culture age and polyol content. In conclusion, our findings indicate beneficial effects of endogenous polyols in improving shelf life of encapsulated mycelium and this may spur the successful development of microbial biocontrol agents in the future. 相似文献
82.
Qingjie Liu Douglas G. Batt Charu Chaudhry Jonathan S. Lippy Mark A. Pattoli Neha Surti Songmei Xu Percy H. Carter James R. Burke Joseph A. Tino 《Bioorganic & medicinal chemistry letters》2018,28(18):3080-3084
Incorporation of a suitably-placed electrophilic group transformed a series of reversible BTK inhibitors based on carbazole-1-carboxamide and tetrahydrocarbazole-1-carboxamide into potent, irreversible inhibitors. Removal of one ring from the core of these compounds provided a potent irreversible series of 2,3-dimethylindole-7-carboxamides having excellent potency and improved selectivity, with the additional advantages of reduced lipophilicity and molecular weight. 相似文献
83.
Polymalatase from Physarum polycephalum calalysed the hydrolysis of beta-poly[L-malate] and of the synthetic compounds beta-di(L-malate), beta-tetra(L-malate), beta-tetra(L-malate) beta-propylester, and L-malate beta-methylester. Cyclic beta-tri(L-malate), cyclic beta-tetra(L-malate), and D-malate beta-methylester were not cleaved, but were competitive inhibitors. The O-terminal acetate of beta-tetra(L-malate) was neither a substrate nor an inhibitor. L-Malate was liberated; the Km, Ki and Vmax values were measured. The appearance of comparable amounts of beta-tri(L-malate), and beta-di(L-malate) during the cleavage of beta-tetra(L-malate) indicated a distributive mechanism for small substrates. The accumulation of a series of oligomers, peaking with the 11-mer and 12-mer in the absence of higher intermediates, indicated that the depolymerization of beta-poly(L-malate) was processive. The results indicate that beta-poly(L-malate) is anchored at its OH-terminus by the highly specific binding of the penultimate malyl residue. The malyl moieties beyond 12 residues downstream from the OH-terminus extend into a diffuse second, electrostatic binding site. The catalytic site joins the first binding site, accounting for the cleavage of the polymer into malate residues. It is proposed that the enzyme does not dissociate from beta-poly(L-malate) during hydrolysis, when both sites are filled with the polymer. When only the first binding site is filled, the reaction partitions at each oligomer between hydrolysis and dissociation. 相似文献
84.
Human leukocyte elastase and cathepsin G were isolated from purulent sputum by a simple procedure involving chromatography on elastin-agarose. Salt extracts of sputum were prepared, treated with DNase, and the precipitate which formed extracted and applied to a column of soluble elastin-Sepharose 4B. Contaminating protein was eluted with 50 mM Tris, 50 mM NaCl, pH 8.0 and then two column volumes of 50 mM acetate, 1.0 M NaCl, pH 5.0. The tightly bound elastase and cathepsin G together with a trypsin-like serine protease could finally be eluted with 50 mM acetate, 1.0 M NaCl, 20% DMSO, pH 5.0. Resolution of the proteases was accomplished by cation-exchange chromatography. Disc gel electrophoresis established the purity of elastase and cathepsin G and confirmed the existence of several isozymes for each. 相似文献
85.
Robert Krell 《CMAJ》1972,107(9):867-872
Case reports on single-parents families demonstrate some unique problems with which such a family unit must cope. Single mothers frequently present children to the family physician, pediatrician or child psychiatrist with specific symptom complaints. There exists a need to recognize that these symptoms may reflect the special problems of the single-parent family or unresolved issues which led to the formation of the unit.To meet the needs of these parents the physician must explore the specific circumstances of such a family in some depth. Nonjudgmental recognition of their problems may decrease the tendency to view these problems as “psychiatric”. Increased awareness of this entity as a new social unit will help the physician choose proper techniques and appropriate resources to provide support. 相似文献
86.
Quantitative estimation of transcellular and paracellular pathways of biliary sucrose in isolated perfused rat liver. 总被引:2,自引:1,他引:1 下载免费PDF全文
A method was developed to estimate the relative contributions of paracellular and transcellular pathways to the total biliary clearance of sucrose in isolated perfused rat liver. When livers were perfused with a sucrose-containing medium (1 mM), biliary sucrose concentration reached an equilibrium of 165 +/- 27 microM within 10 min, without further significant change up to 40 min. After removal of sucrose from the perfusate, the decrease of the sucrose concentration in bile was found to obey biphasic first-order kinetics, showing a rapid initial decrease (half-life 3.3 +/- 0.5 min) and then a slower decrease (half-life 29.4 +/- 5.7 min). Both phases of decrease were further characterized. Pretreating rats with the cholestatic agents alpha-naphthyl isothiocyanate (ANIT), oestradiol valerate (OV) and colchicine increased the biliary equilibrium concentration and decreased the half-life of the fast phase of the biliary sucrose elimination. The slow phase was unaffected in the livers of ANIT- and OV-treated rats. The slow phase of biliary sucrose efflux was sensitive to colchicine treatment. A close correlation was observed between the slow-phase fraction of the biliary sucrose and the corresponding sucrose content of the liver. By quantitative analysis of the efflux kinetics the relative contribution of the paracellular pathway to the biliary clearance of sucrose was estimated to be 83 +/- 2% in control livers, which increased to about 90% in livers of pretreated animals. These results are important in view of the use of sucrose in evaluating the paracellular-pathway permeability in intra- and extra-hepatic cholestasis. 相似文献
87.
The novel synthetic inhibitor of matrix metalloproteinases Ro 28-2653 induces apoptosis in Dunning tumor cells 总被引:3,自引:0,他引:3
Mangoldt D Sinn B Lein M Krell HW Schnorr D Loening SA Jung K 《Apoptosis : an international journal on programmed cell death》2002,7(3):217-220
The effect of synthetic inhibitors of matrix metalloproteinases (MMP) has been shown against a variety of tumors in preclinical models. Ro 28-2653, a novel synthetic MMP inhibitor, is able to reduce tumor growth in orthotopic prostatic cancer in rats (R3327 Dunning tumor). However, at present this inhibitory mechanism in tumor inhibition in vivo can only be partly explained by the inhibition of the catalytic activity of MMPs overexpressed in cancereous tissue. Using the flow cytometric method, we have investigated the effect of various concentrations of Ro 28-2653 on the Dunning tumor cells with regard to the staining of F-actin and DNA as markers of apoptosis. In combination with fluorescence microscopy we detected the loss of F-actin and the degradation of internucleosomal DNA. This effect of Ro 28-2653 on apoptosis was dose- and time-dependent increasing with concentration between 10 and 100 g/ml as well as with time of treatment between 24 and 48 h. 相似文献
88.
The carbon count of 2000 years of rice cultivation 总被引:2,自引:0,他引:2
Karsten Kalbitz Klaus Kaiser Sabine Fiedler Angelika Kölbl Wulf Amelung Tino Bräuer Zhihong Cao Axel Don Piet Grootes Reinhold Jahn Lorenz Schwark Vanessa Vogelsang Livia Wissing Ingrid Kögel‐Knabner 《Global Change Biology》2013,19(4):1107-1113
More than 50% of the world's population feeds on rice. Soils used for rice production are mostly managed under submerged conditions (paddy soils). This management, which favors carbon sequestration, potentially decouples surface from subsurface carbon cycling. The objective of this study was to elucidate the long‐term rates of carbon accrual in surface and subsurface soil horizons relative to those of soils under nonpaddy management. We assessed changes in total soil organic as well as of inorganic carbon stocks along a 2000‐year chronosequence of soils under paddy and adjacent nonpaddy management in the Yangtze delta, China. The initial organic carbon accumulation phase lasts much longer and is more intensive than previously assumed, e.g., by the Intergovernmental Panel on Climate Change (IPCC). Paddy topsoils accumulated 170–178 kg organic carbon ha?1 a?1 in the first 300 years; subsoils lost 29–84 kg organic carbon ha?1 a?1 during this period of time. Subsoil carbon losses were largest during the first 50 years after land embankment and again large beyond 700 years of cultivation, due to inorganic carbonate weathering and the lack of organic carbon replenishment. Carbon losses in subsoils may therefore offset soil carbon gains or losses in the surface soils. We strongly recommend including subsoils into global carbon accounting schemes, particularly for paddy fields. 相似文献
89.
J.S. Fedyna D.W. Snyder D. Aharony D. Redkar-Brown R.D. Krell 《Prostaglandins & other lipid mediators》1990,39(5)
The actions of the peptide leukotriene (LT) LTC4, LTD4 and LTE4 and phenylephrine (PE) were studied in isolated left branches of the guiena-pig pulmonary artery (GPPA). Indomethacin 5 × 10−6 M enhanced both the potency and maximal response of all agonists, but the effect on LTD4 and LTE4 was larger. The influence of indomethacin suggests the release of an endogenous vasodilating cyclooxygenase product in GPPA. In the pressence of indomethacin the rank-order of potency was LTC4 > LTD4 > LTE4 ≥ PE with respective pD2 vaues of 7.65, 7.39, 6.35 and 6.26. All further studies were carried out in the presence of 5 × 10−6 indomethacin. Removal of the endothelium further increased both potency (> 3-fold) and the maximal response of all agonists tested, indicating that a non-clycooxygenase endothelium-dependent relaxing factor may be present in GPPA. In separate studies, GPPA was demonstrated capable of metabolizing 3H-LTC4 by an L-serine borate inhibitable γ-glutamyl transpeptidase. In contrast, relatively little formation of 3H-LTE4 was apparent either from 3H-LTC4 or 3H-LTD4. The LTD4-selective antagonists, LY 171,883 and ICI 198,615 had -log molar KB values of 6.07 ± 0.14 and 9.38 ± 0.32, respectively, against LTD4 in the absence of endothelium. The ability of LY 171,883 to antagonize LTC4 was eliminated in the presence of 45 mM serine borate in endothelium denuded tissues. LT receptors in GPPA appear to be heterogeneous and similar to guinea pig ariway receptors. 相似文献
90.