Carbohydrate changes in kiwifruit buds during the onset and release from dormancy     

Annette C. Richardson  Eric F. Walton  John S. Meekings  Helen L. Boldingh 《Scientia Horticulturae》2010

Carbohydrates were measured in axillary bud meristems from kiwifruit (Actinidia deliciosa (A.Chev.) C.F. Liang et A.R. Ferguson cultivar Hayward) to determine whether concentrations changed during winter dormancy. Buds were collected from kiwifruit vines growing in four sites, which spanned the climatic range that kiwifruit are grown in New Zealand, and from vines where the time of budbreak had been manipulated using hydrogen cyanamide. During winter, sugars comprised 78% of measured carbohydrates in meristems, with sucrose accounting for more than 86% of sugars detected (up to 200 mg g DW⁻¹). Starch concentrations in bud meristems showed little change during winter. Meristem sucrose and hexose concentrations increased rapidly from autumn until mid-winter, and this was correlated with leaf abscission. Sugar accumulation ceased in mid-winter and concentrations remained stable until spring, suggesting that bud meristem activity was low. Four weeks before visible bud movement, a marked decline in sucrose and increase in hexose concentrations, indicated activity in the meristems had increased prior to budbreak. The patterns of seasonal change and peak sucrose concentrations in meristems were similar at all sites. The only difference was in the timing of events, with changes in meristem sugars occurring earliest in vines growing at the coolest site, coinciding with their earlier cessation of and resumption of vine growth. Advancing budbreak, by applying hydrogen cyanamide to vines in late winter, also advanced changes in sugar concentrations within meristems. This work suggests that the concentration of sucrose in kiwifruit bud meristems has utility as an indicator of whether they are being induced into, maintained or released from winter dormancy.  相似文献   

A Bayesian approach to assess the accuracy of a diagnostic test based on plant disease measurement     

David Makowski  Jean-Baptiste Denis  Laurent Ruck  Annette Penaud 《Crop Protection》2008,27(8):1187-1193

The proportion of diseased plant organs measured before chemical treatment is often used to make an assessment of the need for crop protection in agricultural plots, but such diagnostic tests are not perfect and sometimes lead to incorrect decisions. The area under the receiver operating characteristic (ROC) curve is a popular index of the overall performance of a test. It can be interpreted as the probability that the test value for a randomly chosen diseased subject will exceed that of a randomly chosen disease-free subject. In this paper, we present a Gaussian/Binomial model to assess the accuracy of diagnostic test based on a measured proportion of diseased plant organs. The model parameters were estimated from a real dataset and the model was used to analyse the accuracy of a diagnostic test based on a measured proportion of oilseed rape flowers contaminated by Sclerotinia sclerotiorum. The results showed that the accuracy of the test depends on the number of collected flowers, but that it is not necessary to collect more than 40 flowers per plot. A simulation study showed that the bias of the estimator of the area under the ROC curve was near zero for all size of dataset and that its mean-square error decreased in function of the number of experimental plots used in the ROC analysis. A major interest of our approach is that it allows one to study the effect of the sample size of the organs on the accuracy of the test. It can also be used to estimate the probability of disease occurrence, and to determine a decision threshold according to the sensitivity and specificity values.  相似文献   

Topography of the casein micelle surface by surface plasmon resonance (SPR) using a selection of specific monoclonal antibodies     

Dupont D  Johansson A  Marchin S  Rolet-Repecaud O  Marchesseau S  Leonil J 《Journal of agricultural and food chemistry》2011,59(15):8375-8384

Several theoretical models of the casein micelle structure have been proposed in the past, but the exact organization of the four individual caseins (α(s1), α(s2), β, and κ) within this supramolecular structure remains unknown. The present study aims at determining the topography of the casein micelle surface by following the interaction between 44 monoclonal antibodies specific for different epitopes of α(s1)-, α(s2)-, β-, and κ-casein and the casein micelle in real time and no labeling using a surface plasmon resonance (SPR)-based biosensor. Although the four individual caseins were found to be accessible for antibody binding, data confirmed that the C-terminal extremity of κ-casein was highly accessible and located at the periphery of the structure. When casein micelles were submitted to proteolysis, the C-terminal extremity of κ-casein was rapidly hydrolyzed. Disintegration of the micellar structure resulted in an increased access for antibodies to hydrophobic areas of α(s1)- and α(s2)-casein.  相似文献   

Response of soil microflora to changes in nematode abundance — evidence for large scale effects in grassland soil+     

Ilja Sonnemann  Hülya Dogan  Annette Klein  Barbara Pieper  Klemens Ekschmitt  Volkmar Wolters 《植物养料与土壤学杂志》1999,162(4):385-391

The effect of increasing nematode abundance on microbial biomass and activity in a temperate grassland soil was investigated in a microcosm experiment. The experiment lasted for 33 days. The natural nematode diversity, as well as relevant aspects of the spatial heterogeneity of the soil microhabitat in a 80 m² sampling area were maintained in the microcosms. No correlation was found between nematode abundance and microbial biomass (CFE) or ergosterol content (as a measure of active fungal biomass). However, a doubling of nematode abundance reduced CO₂ production by 11 % and increased bacterial substrate utilization (BIOLOG) by 18 %. A possible explanation is that fungal activity was strongly reduced at higher nematode density, overcompensating the simultaneous increase in bacterial activity. The results show that the nematode community in a grassland soil is capable of causing a considerable shift in soil microbial activities towards an increased bacterial metabolism, overriding the spatial heterogeneity of the soil habitat and the taxonomic diversity of the community itself, and thereby producing functional effects relevant at spatial scales that far exceed the activity domains of the organisms involved.  相似文献   

Biotic and abiotic drivers of intraspecific trait variation within plant populations of three herbaceous plant species along a latitudinal gradient     

Kenny Helsen  Kamal P. Acharya  Jörg Brunet  Sara A. O. Cousins  Guillaume Decocq  Martin Hermy  Annette Kolb  Isgard H. Lemke  Jonathan Lenoir  Jan Plue  Kris Verheyen  Pieter De Frenne  Bente J. Graae 《BMC ecology》2017,17(1):38

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Impact of fertilizers on total microbiological flora in planted and unplanted soils of long-term fertilization experiment     

Neeru Narula  Annette Deubel  Andreas Gransee  Rishi Kumar Behl  Wolfgang Merbach 《Archives of Agronomy and Soil Science》2013,59(3):171-180

Microbial population both in diversity as well as numbers in soil is influenced by the amount and type of various compounds entering soil through plant litter, root exudates and management factors like mineral and organic fertilizers under various climatic conditions. This in turn affects crop production and sustainability of soil health. Therefore, we tested total and number of various groups of microflora and also substrate use by Biolog to assess the metabolic capabilities of various groups of microbes from soils of long term fertilization experiment, Halle (Germany) having different mineral and organic fertilizer treatments in unplanted and planted soils with two crops viz., Secale cereale and Medicago sativa . High number of total microorganisms, nitrogen fixers and phosphate solubilizers were observed in the rhizosphere of Medicago sativa and Secale cereale compared to bulk soils. Microbial counts were specially higher in treatments of NPK+FYM (farmyard manure) and NPK in Secale. Medicago had more P solubilizers in yearly addition of phosphatic fertilizers compared to three yearly treatment. During substrate utilization test (Biolog) maximum utilization was found for sugars followed by amino acids in Secale whereas in Medicago sugars were followed by carboxylic acids.  相似文献   

Severe drought-induced community tolerance to heat wave. An experimental study on soil microbial processes     

Annette?BérardEmail author  Meriem?Ben Sassi  Pierre?Renault  Raphael?Gros 《Journal of Soils and Sediments》2012,12(4):513-518

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Spatial predictors of bovine tuberculosis infection and Brucella spp. exposure in pastoralist and agropastoralist livestock herds in the Ruaha ecosystem of Tanzania     

Annette Roug  Deana Clifford  Jonna Mazet  Rudovick Kazwala  Julius John  Peter Coppolillo  Woutrina Smith 《Tropical animal health and production》2014,46(5):837-843

While many studies investigate animal-related risk factors for disease, few have considered environmental or spatial risk factors in the dynamics of bovine tuberculosis (bTB) and brucellosis. In the Ruaha ecosystem of Tanzania, we investigated the role of household location as a predictor for infection with Mycobacterium bovis and exposure to Brucella in pastoralist and agropastoralist cattle herds in a typical African wildlife-livestock-human interface. ArcGIS was utilized to calculate Euclidian distances between households and the nearest river, village center, protected area, and other infected households, followed by multivariate logistic regression to assess the association between risk factors and herd-level bTB and Brucella outcomes. Global and local spatial clustering of bTB-infected and Brucella-exposed herds was explored using the Cuzick-Edward’s test and SaTScan spatial scan statistics. Households located farther from rivers and closer to village centers and herds belonging to agropastoralists were more likely to have bTB-positive cattle. Risk of Brucella exposure increased with proximity to protected areas. One spatial cluster of households with Brucella spp. seropositive cattle was identified. Spatial factors may be useful for assessing disease risk and for formulating intervention and control strategies for households that manage cattle in ecosystems characterized by seasonally limited resources and intense wildlife-livestock interfaces.  相似文献   

Meta-analyses including data from observational studies     

Annette M. O’Connor  Jan M. Sargeant 《Preventive veterinary medicine》2014

Observational studies represent a wide group of studies where the disease or condition of interest is naturally occurring and the investigator does not control allocation to interventions or exposures. Observational studies are used to test hypotheses about the efficacy of interventions or about exposure-disease relationships, to estimate incidence or prevalence of conditions, and to assess the sensitivity and specificity of diagnostic assays. Experimental-study designs and randomized controlled trials (RCTs) can also contribute to the body of evidence about such questions. Meta-analyses (either with or without systematic reviews) aim to combine information from primary research studies to better describe the entire body of work. The aim of meta-analyses may be to obtain a summary effect size, or to understand factors that affect effect sizes. In this paper, we discuss the role of observational studies in meta-analysis questions and some factors to consider when deciding whether a meta-analysis should include results from such studies. Our suggestion is that one should only include studies that are not at high risk of inherent bias when calculating a summary effect size. Study design however can be a meaningful variable in assessment of outcome heterogeneity.  相似文献   

Primary renal neoplasia of dogs     

Bryan JN  Henry CJ  Turnquist SE  Tyler JW  Liptak JM  Rizzo SA  Sfiligoi G  Steinberg SJ  Smith AN  Jackson T 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2006,20(5):1155-1160

BACKGROUND: Primary renal tumors are diagnosed uncommonly in dogs. HYPOTHESIS: Signs and survival will differ among different categories of primary renal tumors. ANIMALS: Data were collected from the medical records of 82 dogs with primary renal tumors diagnosed by examination of tissue obtained by ultrasound-guided biopsy, needle aspiration, surgery, or at postmortem examination. METHODS: This was a multi-institutional, retrospective study. RESULTS: Forty-nine dogs had carcinomas, 28 had sarcomas, and 5 had nephroblastomas. The dogs were geriatric (mean 8.1 years; range: 1-17) with a weight of 24.9 kg (range: 4.5-80). Tumors occurred with equal frequency in each kidney with 4% occurring bilaterally. Initial signs included one or more of hematuria, inappetance, lethargy. weight loss, or a palpable abdominal mass. Pain was reported more frequently in dogs with sarcomas (5/28). The most common hematologic abnormalities were neutrophilia (22/63), anemia (21/64), and thrombocytopenia (6/68). Polycythemia was present in 3 dogs and resolved with treatment. Hematuria (28/49), pyuria (26/49), proteinuria (24/50), and isosthenuria (20/56) were the most frequently observed abnormalities on urinalysis. Pulmonary metastases were noted on thoracic radiographs in 16% of dogs at diagnosis. Seventy-seven percent of dogs had metastatic disease at the time of death. Median survival for dogs with carcinomas was 16 months (range 0-59 months), for dogs with sarcomas 9 months (range 0-70 months), and for dogs with nephroblastomas 6 months (range 0-6 months). CONCLUSIONS AND CLINICAL IMPORTANCE: Primary renal tumors in dogs are generally highly malignant with surgery being the only treatment that improves survival.  相似文献