Impact of xylanases with different substrate selectivity on gluten-starch separation of wheat flour

The influence on wheat flour gluten-starch separation of a xylanase from Aspergillus aculeatus (XAA) with hydrolysis selectivity toward water extractable arabinoxylan (WE-AX) and that is not inhibited by wheat flour xylanase inhibitors was compared to that of a xylanase from Bacillus subtilis (XBS) with hydrolysis selectivity toward water unextractable arabinoxylan (WU-AX) and that is inhibited by such inhibitors. XAA improved gluten agglomeration through degradation of WE-AX and concomitant reduction in viscosity, which in the laboratory scale batter procedure with a set of vibrating sieves (400, 250, and 125 microm), increased protein recoveries on the 400 microm sieve. In contrast, XBS had a negative effect as it decreased gluten protein recovery on this sieve, probably as a result of the viscosity increase that accompanied WU-AX solubilization. Hence, it was active even if most likely a considerable part of its activity was prevented by xylanase inhibitors. A combination of XAA and XBS at a low dosage yielded a distribution of gluten proteins on the different sieves comparable to that of the control. At a high combined dosage, the gluten agglomeration was better than that with XAA alone, indicating that both WE-AX and WU-AX have a negative impact on gluten agglomeration. Finally, experiments with endoxylanase addition at different moments during the separation process suggest that the status of the arabinoxylan population during dough mixing is far less critical for its impact on gluten agglomeration than that during the batter phase.     

Climate/growth relationships in a <Emphasis Type="Italic">Pinus cembra</Emphasis> high-elevation network in the Southern French Alps

•Introduction  

In the context of climate change, assessing climate–growth relationships is of high importance in order to understand how forest ecosystems evolve and to test climate models at regional scale.     

Shedding light on the migratory patterns of the Amazonian goliath catfish,Brachyplatystoma platynemum,using otolith 87Sr/86Sr analyses

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Ecoviability for ecosystem‐based fisheries management

Reconciling food security, economic development and biodiversity conservation is a key challenge, especially in the face of the demographic transition characterizing many countries in the world. Fisheries and marine ecosystems constitute a difficult application of this bio‐economic challenge. Many experts and scientists advocate an ecosystem approach to manage marine socio‐ecosystems for their sustainability and resilience. However, the ways by which to operationalize ecosystem‐based fisheries management (EBFM) remain poorly specified. We propose a specific methodological framework—viability modelling—to do so. We show how viability modelling can be applied using four contrasted case‐studies: two small‐scale fisheries in South America and Pacific and two larger‐scale fisheries in Europe and Australia. The four fisheries are analysed using the same modelling framework, structured around a set of common methods, indicators and scenarios. The calibrated models are dynamic, multispecies and multifleet and account for various sources of uncertainty. A multicriteria evaluation is used to assess the scenarios’ outcomes over a long time horizon with different constraints based on ecological, social and economic reference points. Results show to what extent the bio‐economic and ecosystem risks associated with the adoption of status quo strategies are relatively high and challenge the implementation of EBFM. In contrast, strategies called ecoviability or co‐viability strategies, that aim at satisfying the viability constraints, reduce significantly these ecological and economic risks and promote EBFM. The gains associated with those ecoviability strategies, however, decrease with the intensity of regulations imposed on these fisheries.     

Diagnosis and management of small-scale fisheries in developing countries

Small‐scale fisheries (SSF) make important but undervalued contributions to the economies of some of the world’s poorest countries. They also provide much of the animal protein needed by societies in which food security remains a pressing issue. Assessment and management of these fisheries is usually inadequate or absent and they continue to fall short of their potential as engines for development and social change. In this study, we bring together existing theory and methods to suggest a general scheme for diagnosing and managing SSF. This approach can be adapted to accommodate the diversity of these fisheries in the developing world. Many threats and solutions to the problems that beset SSF come from outside the domain of the fishery. Significant improvements in prospects for fisheries will require major changes in societal priorities and values, with consequent improvements in policy and governance. Changes in development policy and science reflect these imperatives but there remains a need for intra‐sectoral management that builds resilience and reduces vulnerability to those forces beyond the influence of small‐scale fishers.     

Production and preliminary characterization of monoclonal antibodies raised against <Emphasis Type="Italic">Xanthomonas campestris</Emphasis> pv. <Emphasis Type="Italic">mangiferaeindicae</Emphasis>

Bacterial black spot disease of mango is caused by Xanthomonas campestris pv. mangiferaeindicae (Xcm), which consists of two genotypically and phenotypically distinct groups of strains. Monoclonal antibodies (MABs) were produced – 15 against CFBP 1717, a group I strain, and 9 against CFBP 2919 (yellow-pigmented), a group II strain – and were analyzed for their characteristics. On the avidin-biotin peroxidase complex enzyme-linked immunosorbent assay, the dilution limit of the MABs was between 100 and 200000 and was 10 times higher when measured on the corresponding ascitic fluid. All kinds of isotypes were represented among the MABs. All the Japanese Xcm strains, designated group I by hrp-restriction fragment length polymorphism (RFLP) analysis, reacted equally with MAB 1A7H12G3, which is the most specific for all but one worldwide group I strains, and to only one strain among group II. Also, to various extents, serological heterogeneity inside the two groups was consistently differentiated based on isozyme and RFLP analyses. MAB 1E2E1 against CFBP2919, because of its narrow specificity, and MAB 1A7H12G3 against CFBP1717, because of its broad specificity, will be useful for epidemiological studies or general control of the pathogen.     

New tools for studying epidemiology and resistance of grape powdery mildew to DMI fungicides

Using a Random Amplified Polymorphic DNA (RAPD) assay, we investigated the genetic polymorphism existing among 62 European isolates of the grape powdery mildew fungus (Uncinula necator [Schw.] Burr.). Isolates overwintering as mycelium in buds were genetically distinct from isolates overwintering as ascospores, suggesting the existence of two genetically isolated powdery mildew populations, and consequently of two independent sources of inoculum in the vineyard. Isolates resistant to fungicides inhibiting sterol 14α-demethylation (DMIs) were found in both populations, suggesting that resistance to DMIs may arise independently in the two powdery mildew populations. A PCR assay targeting the gene encoding U. necator 14α-demethylase has been developed which will permit an early, specific detection of U. necator infections, and may be useful for spraying programmes. ©1997 SCI