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71.
This study under field experimental conditions in apple orchard agroecosystems investigated the effects of pest management strategies (i.e. none, organic, conventional and integrated) on enzyme activities, in relation to soil properties. Enzyme activities chosen are implicated in the major biogeochemical nutrient cycles such as C (cellulase, fluoresceine diacetate hydrolase, β-galactosidase, β-glucosidase, phenol oxidase), N (arylamidase), P (acid and alkaline phosphomonoesterases, phosphodiesterase and phosphotriesterase) and S (arylsulfatase). Redundancy analyses and decomposition of the variances were performed to clarify how enzyme activities are affected by management strategy and soil properties. Results showed that the effects and their proportion attributable to management strategy and soil properties varied considerably depending on enzyme activity. Phenol oxidase activity was the only case where total variance was principally explained by management strategy (i.e. conventional and integrated) rather than by soil properties, and thus it seems to be an attractive potential indicator to assess soil quality in this agrochemical context. 相似文献
72.
Fotini A. Koutroumpa Bruno Vincent Géraldine Roux-Morabito Carine Martin François Lieutier 《Annals of Forest Science》2008,65(7):707-707
73.
Emmie Dornez Kurt Gebruers Iris J. Joye Bart De Ketelaere Jonathan Lenartz Carine Massaux Bernard Bodson Jan A. Delcour Christophe M. Courtin 《Journal of Cereal Science》2008
The effects of genotype, harvest year and their interaction on the levels of arabinoxylans (AX), endoxylanases and endoxylanase inhibitors in wheat were studied using 14 varieties grown in three successive growing periods with diverse climatological conditions. Relations with more commonly evaluated wheat characteristics such as yield, thousand kernel weight, specific weight, protein level, Hagberg falling number (HFN) and α-amylase activity level were examined. Water extractable arabinoxylan (WE-AX) levels in wheat varied much more than total arabinoxylan (TOT-AX) levels. This variability was mainly genetically determined, but harvest year also had an important effect. Total endoxylanase activity levels varied more than a factor of 20 between the different wheat samples. Endogenous endoxylanases typically accounted for only 10–15% of this activity, while wheat-associated microbial endoxylanases accounted for the remaining 85–90%. However, when preharvest sprouting occurred, the contribution of endogenous endoxylanases could sometimes amount to over 40% of this total activity. Endogenous endoxylanase activity levels were mainly determined by the interaction of genotype and harvest year, while wheat-associated microbial endoxylanase activity levels were predominantly determined by genotype alone. Endogenous and microbial endoxylanase activity levels were strongly correlated, suggesting that wheat varieties which are susceptible to preharvest sprouting are often also susceptible to microbial contamination. The TAXI and XIP-type endoxylanase inhibitor levels varied by a factor of 8 and 1.8, respectively. They were mainly determined by genotype and were rather similar in the different growing periods. 相似文献
74.
Matheus D. Baldissera Carine F. Souza Carla Cristina Zeppenfeld Sharine Descovi Aleksandro S. da Silva Bernardo Baldisserotto 《Fish physiology and biochemistry》2018,44(4):1051-1059
The phosphotransfer network system, through the enzymes creatine kinase (CK), adenylate kinase (AK), and pyruvate kinase (PK), contributes to efficient intracellular energetic communication between cellular adenosine triphosphate (ATP) consumption and production in tissues with high energetic demand, such as cerebral tissue. Thus, the aim of this study was to evaluate whether aflatoxin B1 (AFB1) intoxication in diet negatively affects the cerebral phosphotransfer network related to impairment of cerebral ATP levels in silver catfish (Rhamdia quelen). Brain cytosolic CK activity decreased in animals fed with a diet contaminated with AFB1 on days 14 and 21 post-feeding, while mitochondrial CK activity increased, when compared to the control group (basal diet). Also, cerebral AK and PK activity decreased in animals fed with a diet contaminated with AFB1 on days 14 and 21 post-feeding, similarly to the results observed for cerebral ATP levels. Based on this evidence, inhibition of cerebral cytosolic CK activity is compensated by stimulation of mitochondrial CK activity in an attempt to prevent impairment of communication between sites of ATP generation and ATP utilization. The inhibition of cerebral AK and PK activity leads to impairment of cerebral energy homeostasis, decreasing the brain’s ATP availability. Moreover, the absence of a reciprocal compensatory mechanism between these enzymes contributes to cerebral energetic imbalance, which may contribute to disease pathophysiology. 相似文献
75.
Couvreur B Letellier C Olivier F Dehan P Elouahabi A Vandenbranden M Ruysschaert JM Hamers C Pastoret PP Kerkhofs P 《Veterinary research》2007,38(6):819-834
We report DNA immunisation experiments in cattle using plasmid constructs that encoded glycoprotein E2 from bovine viral diarrhoea virus (BVDV)-1 (E2.1) and BVDV-2 (E2.2). The coding sequences were optimised for efficient expression in mammalian cells. A modified leader peptide sequence from protein gD of BoHV1 was inserted upstream of the E2 coding sequences for efficient membrane export of the proteins. Recombinant E2 were efficiently expressed in COS7 cells and they presented the native viral epitopes as judged by differential recognition by antisera from cattle infected with BVDV-1 or BVDV-2. Inoculation of pooled plasmid DNA in young cattle elicited antibodies capable of neutralising viral strains representing the major circulating BVDV genotypes. 相似文献
76.
In the search for bioactive natural products, our lab screens hydrophobic extracts from marine fungal strains. While hydrophilic active substances were recently identified from marine macro-organisms, there was a lack of reported metabolites in the marine fungi area. As such, we decided to develop a general procedure for screening of hydrophobic metabolites. The aim of this study was to compare different processes of fermentation and extraction, using six representative marine fungal strains, in order to define the optimized method for production. The parameters studied were (a) which polar solvent to select, (b) which fermentation method to choose between solid and liquid cultures, (c) which raw material, the mycelium or its medium, to extract and (d) which extraction process to apply. The biochemical analysis and biological evaluations of obtained extracts led to the conclusion that the culture of marine fungi by agar surface fermentation followed by the separate extraction of the mycelium and its medium by a cryo-crushing and an enzymatic digestion with agarase, respectively, was the best procedure when screening for hydrophilic bioactive metabolites. During this development, several bioactivities were detected, confirming the potential of hydrophilic crude extracts in the search for bioactive natural products. 相似文献
77.
Jean Heinrich Daugrois Carine Edon-Jock Sandrine Bonoto Jean Vaillant Philippe Rott 《European journal of plant pathology / European Foundation for Plant Pathology》2011,129(1):71-80
Sugarcane yellow leaf virus, the causal agent of yellow leaf, is transmitted from plant to plant by aphids. Understanding and evaluating the epidemic
risks due to spread of yellow leaf by aphids is an important feature for sugarcane production. Four distinct sugarcane trials
were set up with disease-free plants to study the relationship between spread of yellow leaf, the vector dynamics and environmental
conditions that may favour yellow leaf epidemics. The study was performed by surveys of vector populations and determination
of plant infections. Sugarcane cultivar SP71-6163, highly susceptible to yellow leaf, was analyzed spatially at different
dates in all four trials and compared to commercial cultivars in two of the four trials. These surveys allowed us to identify
a correlation between the aphid dynamics in the field and yellow leaf progress. Additionally, a negative correlation was found
between rainfall during the first weeks after transferring sugarcane plants to the field and aphid dispersal within the field.
This later result revealed an impact of rainfall on aphid invasion and subsequent plant infection by SCYLV. If aphids are
the key factor for disease spread, plant response varied also according to cultivar resistance with high variation depending
on rain conditions. 相似文献