JOURNAL OF FOOD BIOCHEMISTRY, Issue 4 2004
SANG MOO KIM
The effect of side-chain density on the kinetic parameters of a side-chain-cleaving hemicellulase was determined. Kinetic parameters were based on the rate of Trichoderma reesei ,- galactosidase-catalyzed liberation of galactose from galactomannan (guar and locust bean) substrates. The focus enzyme was the predominant ,-galactosidase obtained from the fungus'galactomannan-supplemented cell-free culture medium. Substrate concentrations were based on the number of galactosyl moieties per volume reaction mixture. The Km values for the galactomannan substrates differed approximately 4.3-fold (28.36 and 121.16 ,M), the more branched substrate having the higher Km. In contrast, the corresponding Vmax values were found to be essentially the same. The results indicate the enzyme preferentially acts at sites of low side-chain density. [source]

PROPERTIES OF CYSTEINE PROTEINASE INHIBITORS FROM BLACK GRAM AND RICE BEAN

JOURNAL OF FOOD BIOCHEMISTRY, Issue 3 2001
SOOTTAWAT BENJAKUL
ABSTRACT Cysteine proteinase inhibitors (CPI) were purified to 59 and 54 fold from black gram (Vignaraungo (L.) Hepper) and rice bean (Vignaumbellata Thunb.), respectively, by using heal treatment, followed by chromatography on a carboxymethyl (CM)-papain-Sepharose affinity column. The purified inhibitors were highly inhibitory to papain and Pacific whiting cathepsin L in a concentration dependent manner. They were detected as a dark band on tricine-SDS-PAGE gel stained for inhibitory activity. The apparent molecular weights of purified CPI from black gram and rice bean seeds were estimated to be 12, 000 daltons. The purified inhibitors were thermostable up to 90C and active in the neutral and alkaline pH ranges. [source]

PHASEOLIN RFLP IN BEAN (PHASEOLUS VULGARIS) CULTIVARS

JOURNAL OF FOOD BIOCHEMISTRY, Issue 2 2000
CRISTINA KEIKO TAKAHASHI
ABSTRACT A 0.5 kbp phaseolin gene fragment was used as a probe to study phaseolin restriction fragment length polymorphism (RFLP) in P. vulgaris cultivars. Results obtained from plants displaying type S and type T phaseolin suggest a genomic organization more variable than that previously described. This variability could be exploited to aid gene identification as well as to improve germ plasm bank organization. The same probe was useful in detecting phaseolin linked RFLP in other leguminosae. [source]

pH, TEMPERATURE AND HYDRATION KINETICS OF FABA BEANS (VICIA FABA L.)

JOURNAL OF FOOD PROCESSING AND PRESERVATION, Issue 1 2003
NANOR HALADJIAN
Soaking kinetics of dry faba beans was studied in the temperature range 20,65C, and at pH 3, 6, 9 and 12 by the method of weight gain until equilibrium conditions were attained. Increasing the soaking temperature from 20 to 35C resulted in a small increase in hydration rate constants as compared to that realized with further increase to 50 and 65C in the investigated range of pH. Soaking at 65C decreased the amount of water absorbed by the beans and the time at which equilibrium was attained. Beans soaked at alkaline pH exhibited higher hydration rates especially when hydration was carried out at , 50C [source]

TRAINING, VALIDATION AND MAINTENANCE OF A PANEL TO EVALUATE THE TEXTURE OF DRY BEANS (PHASEOLUS VULGARIS L.)

JOURNAL OF SENSORY STUDIES, Issue 3 2008
R. ROMERO DEL CASTILLO
ABSTRACT The inclusion of dry beans in diets has clear health benefits. However, consumers in developed countries mainly choose beans for their sensory qualities, especially for their texture. This article describes the constitution, training and validation of a panel of judges to evaluate the texture of dry beans. The judges were trained in the perception of different textures, analyzed a wide range of beans and selected seed-coat roughness, seed-coat perceptibility and creaminess/mealiness of the cotyledon as the main attributes to be scored. After training, the panel was capable of discriminating between different varieties of beans and even between beans of the same variety grown at different locations. The analysis of the behavior of the panel in a standard tasting session 2 years after its formation showed that periodic inclusion of samples from the extremes of the scales for the attributes during tasting sessions was sufficient to keep the panel trained. PRACTICAL APPLICATIONS This article could serve as a guide for the training of sensory panels to evaluate the texture of dry beans. It describes the selection of the attributes on which the analysis is based, references for the extreme values of the attributes and how to train the panel. It also provides a practical example of the analysis of the behavior of the panel some time after training. [source]

Good Campers: The History of Australian War Reporting

HISTORY COMPASS (ELECTRONIC), Issue 10 2010
Fay Anderson
When the Chief of British Intelligence told Australia's First Official War Correspondent, C.E.W Bean in October 1914 that war reporters were a ,dying profession', Bean recorded in his diary that on the contrary, he thought it was the beginning of a new era. Bean proved prescient. Since 1863 Australia has had over 750 journalists, photographers and cinematographers covering international conflicts. Despite this tradition, the history of Australian conflict reporting has been neglected by historians. This article will provide an overview of the Australian historiography and the corresponding scholarship in the US and UK. It will also consider seminal issues such as censorship, the mythology and self-mythology surrounding war reporting, media power and the Anzac legend. [source]

Effects of Deficit Irrigation and Salinity Stress on Common Bean (Phaseolus Vulgaris L.) and Mungbean (Vigna Radiata (L.) Wilczek) Grown in a Controlled Environment

JOURNAL OF AGRONOMY AND CROP SCIENCE, Issue 4 2010
M. Bourgault
Abstract As water for irrigation purposes becomes increasingly scarce because of climate change and population growth, there is growing interest in regulated deficit irrigation (RDI) as a way to improve efficiency of water usage and farm productivity in arid and semi-arid areas. Salinity is also becoming an important problem in these same regions. Experiments were performed to investigate the effects of RDI and salt stress on two legumes crops, common bean (Phaseolus vulgaris L.) and mungbean (Vigna radiata (L.) Wilczek); previous work showed contrasting responses to RDI by these two crops under field conditions. The seed and biomass yields of both crops were reduced as a result of increasing water deficit stress; however, mungbean was able to maintain the same proportion of its biomass in reproductive structures and maintain its harvest index under stress, whereas common bean's decreased. In addition, photosynthesis in mungbean was higher than in common bean and higher at the same levels of transpiration. Finally, salinity stress did not affect the water potential, harvest index or the specific leaf weight of either crop. There were no interactions between salinity and crops or RDI levels, which suggest that the two crops do not differ in their response to salinity stress, and that RDI levels do not modify this response. [source]

Evaluation of Common Bean for Drought Tolerance in Juana Diaz, Puerto Rico

JOURNAL OF AGRONOMY AND CROP SCIENCE, Issue 5 2009
T. G. Porch
Abstract Drought tolerance is an increasingly important trait in common bean (Phaseolus vulgaris L.) due to the reduction in water resources, a shift in production areas and increasing input costs. The objective of this study was to evaluate 29 genotypes for drought tolerance under drought stress (DS) and reduced stress treatments in Juana Diaz, Puerto Rico. The use of DS and reduced stress treatments facilitated the identification of drought tolerant germplasm that also had good yield potential under more optimal conditions. Based on the results of seed yield under DS and reduced stress conditions, and DS indices, including the geometric mean (GM), stress tolerance index (STI) and percent yield reduction (YR), genotypes were identified with greater yield potential under the tested environment. Based on average GM over the 2 years, the superior common bean genotypes identified were SEA 5, G 21212, A 686, SEN 21 and SER 21. These genotypes performed well in both years and under both treatment conditions and thus may serve as parents for DS improvement and genetic analysis. [source]

Effects of Interactions of Moisture Regime and Nutrient Addition on Nodulation and Carbon Partitioning in Two Cultivars of Bean (Phaseolus vulgaris L.)

JOURNAL OF AGRONOMY AND CROP SCIENCE, Issue 4 2001
T. Boutraa
Major limitations of bean (Phaseolus vulgaris L.) production in arid and semiarid regions are lack of moisture and low soil fertility. An experiment was conducted to determine the effects of soil moisture and N : P : K (20 : 10 : 10) fertilizer on root and shoot growth of two cultivars of bean: cv. Carioca, an indeterminate Brazilian landrace, and cv. Prince, a determinate cultivar grown in Europe. Carioca appears generally stress-tolerant while Prince is intolerant. Seedlings were grown in pots of non-sterile soil at 30, 60 or 90 % field capacity (FC), and given 0, 0.1 or 1 g (kg soil),1 of compound fertilizer. The soil contained a population of effective Rhizobium. Growth of both cultivars was greatest in the high moisture and high nutrient treatments. Root fractions were highest at low nutrient supply; the effect of water was not significant. Leaf fraction decreased as root fraction increased. Numbers of nodules were highest at high and intermediate moisture when no fertilizer was applied. Numbers were lowest at 30 % FC and at the highest fertilizer rate. Masses of nodules and fractions followed the same pattern. Decreasing water regime reduced the relative growth rate (RGR) of Prince, while Carioca maintained high RGR at unfavourable conditions of water and nutrients. Net assimilation rates (NAR) were unaffected by nutrient addition, and reduced by low moisture regime. Water use efficiencies (WUEs) were reduced by water stress but increased by nutrient deficiency. The water utilization for dry matter production was optimal at 60 % FC. Einflüsse der Interaktionen von Bodendenfeuchte und Düngung auf die Knöllchenbildung und Kohlenstoff verteilung bei zwei Bohnenkultivaren (Phaseolus vulgaris L.) Der begrenzende Hauptfaktor der Bohnenproduktion in ariden und semiariden Regionen sind der Feuchtigkeitsmangel und die Bodenfruchbarkeit. Es wurde ein Experiment durchgeführt, um die Wirkungen des Bodenwassers und von N : P : K (20 : 10 : 10) Dünger auf das Wurzel- und Sproßwachstum an zwei Kultivaren von Bohnen (Phaseolus vulgaris L. cv. Carioca, eine brasilianischen, indeterminierte Landsorte und cv. Prince, eine determinierter in Europa angebauter Kultivar) zu untersuchen. Carioca erscheint grundsätzlich streßtoleranter im Vergleich zu Prince. Die Sämlinge wurden in Gefäßen mit nichtsterilisiertem Boden unter Feldkapazitäten von 30,60 oder 90 % mit 0, 0,1 oder 1 g eines Volldüngers angezogen. Der Boden enthielt eine Population von wirksamem Rhizobium. Das stärkste Wachstum wurde bei beiden Kultivaren unter dem Einfluß des höchsten Feuchtigkeitsgehaltes und der höchsten Düngermenge gefunden. Der Wurzelanteil war bei der geringen Düngermenge am niedrigsten. Der Einfluß der Bodenfeuchtigkeit war nicht signifikant. Der Blattanteil nahm mit zunehmendem Wurzelanteil ab. Die Anzahl der Knötchen war bei hoher und mittlerer Bodenfeuchte und ohne Düngeranwendung am höchsten. Die Anzahl war am geringsten bei 30 % FC und der höchsten Düngermenge. Die Knötchenmasse und ihr Anteil reagierte entsprechend. Abnehmende Bodenfeuchte reduzierte die relative Wachtumsrate (RGR) von Prince, während Carioca einen hohen RGR auch bei ungünstigen Bedingungen bezüglich Wasser und Düngung behielt. Die Nettoassimilationsraten wurden durch die Düngung nicht beeinflußt; sie gingen bei geringer Bodenfeuchte zurück. Die Wassernutzungseffiziens (WUE) wurde bei Wasserstreß reduziert, nahm aber bei Düngermangel zu. Die Wassernutzung für die Trockenmasseproduktion war bei 60 % Feldkapazität am höchsten. [source]

Embryo developmental events and the egg case of the Aleutian skate Bathyraja aleutica (Gilbert) and the Alaska skate Bathyraja parmifera (Bean)

JOURNAL OF FISH BIOLOGY, Issue 3 2009
G. R. Hoff
Embryo development events were correlated with egg-case changes for the Aleutian skate Bathyraja aleutica and the Alaska skate Bathyraja parmifera. Yolk absorption underwent two phases: that of steady absorption during early development and that of rapid yolk absorption during the final development stages. Total length (LT) for 50% of the pre-hatching embryos egg-case jelly disappearance was 92·04 mm (range 81,102 mm) and 99·36 mm (range 81,100 mm) for B. aleutica and B. parmifera, respectively, allowing the inner chamber to open to seawater flow. The tail filament underwent three phases of growth: rapid elongation during early development (<100 mm embryo LT), stasis of tail filament length during the remainder of embryo development and rapid absorption soon after hatching. Complete tail filament development coincided with the disappearance of egg-case jelly. Clasper buds first developed at embryos >70 mm LT for both species and the sex ratio was 1:1 well before hatching. Egg cases that were devoid of an ova or developing embryo were c. 5·0 and 6·5% of the egg cases examined for B. aleutica and B. parmifera, respectively. Measurements showed that egg cases containing only egg jelly were smaller in both width and length than those possessing an ova. Embryo stages were punctuated with distinct events that correlated with egg case changes controlling the internal environment of the developing embryo. [source]

Elaboration and Validation of a Diagrammatic Scale for Epidemiological Studies of Cercospora Leaf Spot of Castor Bean

JOURNAL OF PHYTOPATHOLOGY, Issue 6 2010
Wellington Freire Dos Santos
Abstract The castor bean cercospora leaf spot (Cercospora ricinella Sacc. & Berl.) is a common disease in castor bean crop (Ricinus communis L.), causing defoliation and losses. In spite of this, the evaluation of disease severity is an important decision support for adoption of strategies and tactics for disease control. Therefore the objective of this work was to elaborate and to validate a diagrammatic to evaluate cercospora leaf spot severity in the castor bean. The scale was developed based on six treatments with different irrigation depths plus the control treatment without irrigation. Based on disease incidence analysis, it was possible to select different severity levels per treatment, which were used to define the percentage intervals of foliar diseased area of the diagrammatic scale. In view of the inexistence of standardized methods for the quantification of cercospora leaf spot in the field, the levels of 0%, 0.1 to 1%, 1.1 to 10%, 10.1 to 20% and 20.1 to 45% of lesioned foliar area were established, pointing out the observation that in the interval of 20 to 45% leaf fall started to occur. The scale was tested according its accuracy, precision and reproducibility. For that, 40 leaves with different disease severity levels were appraised by 10 users, without and with the scale, with an interval of seven days between evaluations of the same users. The appraisers obtained better results under utilization of the scale. The scale proposed in this work presented appropriate applicability for cercospora leaf spot evaluation in castor bean. Higher disease intensity was observed in the control and in treatments with higher irrigation depth and lower irrigation frequency. [source]

Effect of Salt Stress on Carbon Metabolism and Bacteroid Respiration in Root Nodules of Common Bean (Phaseolus vulgaris L.)

PLANT BIOLOGY, Issue 4 2000
A. Ferri
Abstract: In the present work, we examined the effect of salinity on growth, N fixation and carbon metabolism in the nodule cytosol and bacteroids of Phaseolus vulgaris, and measured the O2 consumption by bacteroids incubated with or without the addition of exogenous respiratory substrates. The aim was to ascertain whether the compounds that accumulate under salt stress can increase bacteroid respiration and whether this capacity changes in response to salinity in root nodules of Phaseolus vulgaris. The plants were grown in a controlled environment chamber, and 50, 100 mM or no NaCl (control) was added to the nutrient solution. Two harvests were made, at the vegetative growth period and at the beginning of the reproductive period. The enzyme activities in the nodule cytosol were reduced by the salt treatments, while in the bacteroid cytosol the enzyme activities increased at high salt concentrations at the first harvest and for ADH in all treatments. The data presented here confirm that succinate and malate are the preferred substrates for bacteroid respiration in common bean, but these bacteroids may also utilize glucose, either in control or under saline conditions. The addition of proline or lactate to the incubation medium significantly raised oxygen consumption in the bacteroids isolated from plants treated with salt. [source]

The Effect of Discounting on Policy Choices in Inflation Targeting Regimes,

THE ECONOMIC JOURNAL, Issue 508 2006
SGB Henry
This article assesses the implications of discounting on a result derived by Bean (1998): that in a model of monetary policy where policy acts with a lag, the outcomes of monetary policy are very similar for a wide range of preferences of the monetary authority with respect to inflation and output stability. We show that when the authority discounts the future, outcomes become more sensitive to its preferences, and that it is important to take the discount rate into account when examining the question of how the authority's remit should be specified. [source]

A Possession for Ever: Charles Bean, the Ancient Greeks, and Military Commemoration in Australia

AUSTRALIAN JOURNAL OF POLITICS AND HISTORY, Issue 3 2007
Peter Londey
For many people after the First World War, the classical world of Greece and Rome provided a language of commemoration; those who fought on Gallipoli were often keen to see parallels with the Trojan war of 3,000 years earlier. Charles Bean, Australia's classically-educated war correspondent, Official Historian, and chief visionary behind the Australian War Memorial, was as imbued with the classics as any. What is striking, however, is that Bean largely ignored parallels with Troy, focusing instead almost exclusively on fifth-century BC Athens. Bean wanted more than a language of commemoration; he desired an historical backdrop which would emphasise the place in history of the Australian Imperial Force (AIF). Only the Athenians could provide a fitting parallel for the youthful democracy of Australia. [source]

Microbiological and Toxicological Effects of Perla Black Bean (Phaseolus vulgaris L.) Extracts: In Vitro and In Vivo Studies

BASIC AND CLINICAL PHARMACOLOGY & TOXICOLOGY, Issue 2 2009
Víctor Javier Lara-Díaz
Three different solvents were used to obtain Perla black bean extracts. All three Perla black bean extracts were tested for antibacterial and antiparasitic activity and further analysed for intrinsic cytotoxicity (IC50). Methanol Perla black bean extract was used for acute toxicity test in rats, with the up-and-down doping method. All Perla black bean extracts inhibited bacterial growth. Pseudomonas aeruginosa, Proteus vulgaris, Klebsiella oxytoca, Enterococcus faecalis, Staphylococcus aureus, Staphylococcus epidermidis and Listeria monocytogenes showed inhibition, while Escherichia coli and Enterobacter aerogenes did not. Acidified water and acetic acid Perla black bean extract were tested in parasites. The best IC50 was observed for Giardia lamblia, while higher concentrations were active against Entamoeba histolytica and Trichomonas vaginalis. The Vero cells toxicity levels (IC50) for methanol, acidified water and acetic acid Perla black bean extract were [mean ± S.D. (95% CI)]: 275 ± 6.2 (267.9,282.0), 390 ± 4.6 (384.8,395.2) and 209 ± 3.39 (205.6,212.4) µg/ml, respectively. In vivo acute toxicity assays did not show changes in absolute organ weights, gross and histological examinations of selected tissues or functional tests. The acetic acid and methanol Perla black bean extract proved to exhibit strong antibacterial activity and the acidified water Perla black bean extract exerted parasiticidal effects against Giardia lamblia, Entamoeba hystolitica and Trichomonas vaginalis. The three Perla black bean extracts assayed over Vero cells showed very low toxicity and the methanol Perla black bean extract in vivo did not cause toxicity. [source]

pH, TEMPERATURE AND HYDRATION KINETICS OF FABA BEANS (VICIA FABA L.)

Physicochemical Characteristics of Green Coffee: Comparison of Graded and Defective Beans

JOURNAL OF FOOD SCIENCE, Issue 5 2007
K. Ramalakshmi
ABSTRACT:, Defective (triage) coffee beans are beans rejected after separating the graded ones according to the size and color. These coffee beans represent about 15% to 20% of coffee production in India but are not utilized for beverages since these affect the quality of coffee brew. In the present study, physical characteristics such as bean density, brightness, titratable acidity, pH, moisture, and total soluble solids and also chemical composition, namely, caffeine, chlorogenic acids, lipids, sucrose, total polyphenols, and proteins, were evaluated in defective as well as in graded green coffee beans. The physical parameters such as weight, density, and brightness of defective coffee beans were low compared to the graded beans, which is due to the presence of immature, broken, bleached, and black beans. Caffeine content was low in triage beans compared to graded beans. Chlorogenic acids, one of the composition in coffee responsible for antioxidant activity, was found to be intact (marginally high in some cases) in defective coffee beans. Hence, triage coffee beans can be evaluated as a source of antioxidant or radical scavenging conserve for food systems. [source]

Soluble Albumin and Biological Value of Protein in Cocoa (Theobroma cacao L.) Beans as a Function of Roasting Time

JOURNAL OF FOOD SCIENCE, Issue 4 2005
Luis Abecia-Soria
ABSTRACT: An association has been identified between the extent of roasting and the amount of extractable protein from the cocoa bean, its nutritive value, and the sensorial quality of the liquor. Cocoa nibs from fermented seeds (Theobroma cacao L.) were precision-roasted at 150°C for 0, 30, 34, 38, 42, and 46 min and the protein fraction extracted. From the beginning of roasting, until minute 38, about 87% of the proteins were extractable, but the extractability substantially decreased to 72.7% at 42 min and to 65.3% at 46 min. Both total soluble protein determination and albumin concentration of the roasted nibs diminished slightly until minute 38, when acceptable sensory characteristics were obtained for the liquor. Both total nitrogen and capillary-electrophoretic separation and quantification of the albumin showed that the amounts of extractable protein in this fraction consistently followed a cyclic pattern until minute 42, irreversibly decreasing thereafter. Biological evaluation of the protein from the cocoa nibs roasted for the various times showed that at the point that the sensory rating approached that of a commercial liquor, the albumin content and nutritive value were still high. The findings suggest that with moderate, uniform roasting it may not be necessary to sacrifice the protein's biological value for the sensorial attributes of chocolate in a standard commercial roast. [source]

Quality Evaluation of Pinto Beans and Green Beans Canned in Two Large Reusable Containers

JOURNAL OF FOOD SCIENCE, Issue 6 2003
W.G. McGlynn
ABSTRACT: As an alternative to standard metal cans, 2 large-scale, reusable containers were constructed with volumetric capacities 3.6 to 3.8 times greater and process times 1.36 to 2.05 times longer than a nr 10 can. Effects of increased process time on product quality were measured by conducting objective color and texture evaluations on green beans and pinto beans canned in both containers. Green beans and pinto beans had comparable texture profiles to beans processed conventionally in nr 10 cans. The color of green beans also was comparable; the color of pinto beans was darker, possibly due to contact with the metal container. Color and texture differences were minimal between inner and outer product layers. [source]

Purification of Angularin, A Novel Antifungal Peptide from Adzuki Beans

JOURNAL OF PEPTIDE SCIENCE, Issue 3 2002
Dr X. Y. Ye
Abstract An antifungal peptide was isolated from the adzuki bean with a procedure involving affinity chromatography on Affi-gel blue gel and ion exchange chromatography on CM-Sepharose. The protein designated angularin was adsorbed on both types of chromatographic media and possessed a molecular weight of 8 kDa. Angularin exhibited antifungal activity against a variety of fungal species including Mycospharella arachidiocola and Botrytis cinerea. It inhibited mycelial growth in B. cinerea with an IC50 of 14.3 µM. Fusarium oxysporum and Rhizoctonia solani were not inhibited. Angularin demonstrated inhibitory activity on translation in the rabbit reticulocyte lysate system (IC50 = 8.0 µM) but did not affect proliferation of splenocytes. The activity of HIV-1 reverse transcriptase was inhibited in the presence of angularin. Its N -terminal sequence was GEPGQKE. Copyright © 2002 European Peptide Society and John Wiley & Sons, Ltd. [source]

Air pollution impedes plant-to-plant communication by volatiles

ECOLOGY LETTERS, Issue 9 2010
James D. Blande
Ecology Letters (2010) 13: 1172,1181 Abstract Volatile organic compounds (VOCs) emitted by damaged plants convey information to undamaged neighbouring plants, and previous research has shown that these signals are effective over short distances in nature. Many herbivore-induced VOCs react with ozone, which is the most important tropospheric air pollutant in rural areas. We used extrafloral nectar (EFN) secretion as a phenotypic indicator of between-plant communication in Phaseolus lunatus L. (Lima bean) and show that an ozone-rich (80 ppb) atmosphere reduces the distance over which signalling occurs. We found that ozone degrades several herbivore-induced VOCs, a likely mechanism reducing communication distances. Direct exposure to 80-ppb ozone did not affect the VOC emissions from P. lunatus. In addition, we demonstrated that high ozone concentrations, 120 and 160 ppb, induced EFN secretion in exposed plants, whereas more moderate concentrations, 80 and 100 ppb, did not. This suggests that ozone can play a complex role in the indirect defence of P. lunatus. [source]

Conspicuous extra-floral nectaries are inducible in Vicia faba

ECOLOGY LETTERS, Issue 6 2003
Edward B. Mondor
Abstract Mutualistic interactions are dynamic associations that vary depending on the costs and benefits to each of the interacting parties. Phenotypic plasticity in mutualistic interactions allows organisms to produce rewards to attract mutualists when the benefits of their presence outweigh the costs of producing the rewards. In ant,plant defensive mutualisms, defences are indirect as plants produce extra-floral nectaries (EFN) to attract predatory ants to deter herbivores. Here we demonstrate that in broad bean, Vicia faba, the overall number of EFNs on a plant increases dramatically following leaf damage. In two damage treatments, removal of: (1) one-third of one leaf in a single leaf pair or (2) one-third of both halves of a single leaf pair, resulted in a 59 and 106% increase in the number of EFNs on the plants, respectively, over 1 week. We suggest that the increased production of visually conspicuous EFNs is an adaptive inducible response, to attract predatory arthropods when risk of herbivory increases. [source]

Plant preference in relation to life history traits in the zoophytophagous predator Dicyphus hesperus

ENTOMOLOGIA EXPERIMENTALIS ET APPLICATA, Issue 1 2004
Juan Antonio Sanchez
Abstract Dicyphus hesperus Knight (Heteroptera: Miridae) is an omnivorous predator used to control pests of greenhouse vegetables. Plant preferences and life history traits were studied using nine plant species: Lycopersicon esculentum Mill. (Solanaceae), Capsicum annuum L. (Solanaceae), Verbascum thapsus L. (Scrophulariaceae), Nepeta cataria L. (Lamiaceae), Stachys albotomentosa (Lamiaceae), Nicotiana tabacum L. (Solanaceae), Vicia sativa L. (Fabaceae), Zea mays L. (Gramineae), and Chrysanthemum coronarium L. (Asteraceae). Plants were selected from among potential target crops, natural hosts, plants used for mass rearing, and plants on which D. hesperus has not been reported. Plant preference was measured by multi-choice host plant selection and oviposition assays. Development and reproduction were measured on each of the plant species on both a plant diet alone and on a plant diet supplemented with Ephestia kuehniella Zeller (Lepidoptera: Pyralidae) eggs. Dicyphus hesperus females and nymphs expressed a preference for some plants over others. Plant preference ranged from low preference plants, such as Z. mays, V. sativa, C. coronarium, and C. annuum, to high preference plants such as V. thapsus, N. tabacum, and S. albotomentosa. When E. kuehniella eggs were supplied, there were few differences in the development time and fecundity of D. hesperus among plants, with the exception of corn and broad bean, where fecundity was lower. On a plant diet alone, nymphs were able to complete their development on V. thapsus, C. annuum, and N. cataria. However, mortality and development time were much lower on V. thapsus than on C. annuum and N. cataria. On most of the plant species D. hesperus did not lay any eggs when fed on a plant diet alone. On V. thapsus, females laid a few eggs and lived longer than when fed on prey. Dicyphus hesperus females tended to prefer host plants on which nymph survival without prey was greatest. [source]

Phenazines and biosurfactants interact in the biological control of soil-borne diseases caused by Pythium spp.

ENVIRONMENTAL MICROBIOLOGY, Issue 3 2008
Maaike Perneel
Summary In this study, the putative role of phenazines and rhamnolipid-biosurfactants, antagonistic metabolites produced by Pseudomonas aeruginosa PNA1, was tested in the biological control of Pythium splendens on bean (Phaseolus vulgaris L) and Pythium myriotylum on cocoyam (Xanthosoma sagittifolium L Schott). A rhamnolipid-deficient and a phenazine-deficient mutant of PNA1 were used either separately or jointly in plant experiments. When the mutants were applied separately, no disease-suppressive effect was observed, although both mutants still produced one of the antagonistic compounds (phenazines or rhamnolipids). When the mutants were concurrently introduced in the soil, the biocontrol activity was restored to wild-type levels. Bean seeds developed significantly less pre-emergence damping-off caused by P. splendens when treated with a mixture of purified phenazine-1-carboxamide and rhamnolipids than with any of the chemicals alone. When phenazines and rhamnolipids were combined at concentrations that had no observable effects when the metabolites were applied separately, mycelial growth of P. myriotylum was significantly reduced. In addition, microscopic analysis revealed substantial vacuolization and disintegration of Pythium hyphae after incubation in liquid medium amended with both metabolites. Results of this study indicate that phenazines and biosurfactants are acting synergistically in the control of Pythium spp. [source]

Molecular weight and humification index as predictors of adsorption for plant- and manure-derived dissolved organic matter to goethite

EUROPEAN JOURNAL OF SOIL SCIENCE, Issue 1 2007
T. Ohno
Summary Sorptive retention of organic matter is important in maintaining the fertility and quality of soils in agricultural ecosystems. However, few sorption studies have been conducted that use dissolved organic matter (DOM) characteristic of agricultural amendments. We investigated the sorption to goethite (,-FeOOH) of DOM extracted from: (i) above-ground biomass of wheat straw (Triticum aestivum L.), maize residue (Zea mays L.), soybean residue (Glycine max (L.) Merr.), and hairy vetch residue (Vivia billosa L.); (ii) below-ground biomass from maize, soybean, canola (Brassica napus L.), and green bean (Phaseolus vulgaris L.); and (iii) beef, dairy, poultry, and pig animal manures. The apparent molecular weight (MWAP) of the DOM was measured by high performance-size exclusion chromatography and ranged from 312 to 1074 g mol,1. The carboxyl-group content of the DOM measured by potentiometric titration ranged from 4.84 to 21.38 mmol(,) g,1 carbon. The humification index (HIX) determined by fluorescence spectrometry varied from 1.15 to 4.33. Sorption was directly related to both MWAP and HIX values of the DOM. Molecular weight analysis of the solution prior to and after sorption indicated that the DOM molecules > 1800 g mol,1 were preferentially sorbed, resulting in fractionation of the DOM upon reaction with goethite. The multiple regression equation, based only on MWAP and HIX parameters, explained 76% of the variance in amount of DOM sorbed. The results indicate that MWAP and HIX are important factors in controlling the sorption of DOM to mineral surfaces. Amendment with materials that release DOM of higher molecular weight and greater humification will result in enhanced initial sorption of DOM to soil solids, thereby contributing to accumulation of a larger soil organic C pool. [source]

Assessment of amino-acid substitutions at tryptophan 16 in ,-galactosidase

FEBS JOURNAL, Issue 5 2000
Elizabeth Maranville
The tryptophan residue at position 16 of coffee bean ,-galactosidase has previously been shown to be essential for enzyme activity. The potential role of this residue in the catalytic mechanism has been further studied by using site-directed mutagenesis to substitute every other amino acid for tryptophan at that site. Mutant enzymes were expressed in Pichia pastoris, a methylotrophic yeast strain, and their kinetic parameters were calculated. Only amino acids containing aromatic rings (phenylalanine and tyrosine) were able to support a significant amount of enzyme activity, but the kinetics and pH profiles of these mutants differed from wild-type. Substitution of arginine, lysine, methionine, or cysteine at position 16 allowed a small amount of enzyme activity with the optimal pH shifted towards more acidic. All other residues abolished enzyme activity. Our data support the hypothesis that tryptophan 16 is affecting the pKa of a carboxyl group at the active site that participates in catalysis. We also describe an assay for continuously measuring enzyme kinetics using fluorogenic 4-methylumbelliferyl substrates. This is useful in screening enzymes from colonies and determining the enzyme kinetics when the enzyme concentration is not known. [source]

Effects of elevated temperature and carbon dioxide on seed-set and yield of kidney bean (Phaseolus vulgaris L.)

GLOBAL CHANGE BIOLOGY, Issue 8 2002
P. V. Vara Prasad
Abstract It is important to quantify and understand the consequences of elevated temperature and carbon dioxide (CO2) on reproductive processes and yield to develop suitable agronomic or genetic management for future climates. The objectives of this research work were (a) to quantify the effects of elevated temperature and CO2 on photosynthesis, pollen production, pollen viability, seed-set, seed number, seeds per pod, seed size, seed yield and dry matter production of kidney bean and (b) to determine if deleterious effects of high temperature on reproductive processes and yield could be compensated by enhanced photosynthesis at elevated CO2 levels. Red kidney bean cv. Montcalm was grown in controlled environments at day/night temperatures ranging from 28/18 to 40/30 °C under ambient (350 µmol mol,1) or elevated (700 µmol mol,1) CO2 levels. There were strong negative relations between temperature over a range of 28/18,40/30 °C and seed-set (slope, ,,6.5% °C,1) and seed number per pod (, 0.34 °C,1) under both ambient and elevated CO2 levels. Exposure to temperature >,28/18 °C also reduced photosynthesis (, 0.3 and ,,0.9 µmol m,2 s,1 °C,1), seed number (, 2.3 and ,,3.3 °C,1) and seed yield (, 1.1 and ,,1.5 g plant,1 °C,1), at both the CO2 levels (ambient and elevated, respectively). Reduced seed-set and seed number at high temperatures was primarily owing to decreased pollen production and pollen viability. Elevated CO2 did not affect seed size but temperature >,31/21 °C linearly reduced seed size by 0.07 g °C,1. Elevated CO2 increased photosynthesis and seed yield by approximately 50 and 24%, respectively. There was no beneficial interaction of CO2 and temperature, and CO2 enrichment did not offset the negative effects of high temperatures on reproductive processes and yield. In conclusion, even with beneficial effects of CO2 enrichment, yield losses owing to high temperature (> 34/24 °C) are likely to occur, particularly if high temperatures coincide with sensitive stages of reproductive development. [source]

On the trail of the global green bean: methodological considerations in multi-site ethnography

GLOBAL NETWORKS, Issue 4 2001
Susanne Freidberg
The need to demystify and ,ground' globalization has spurred many calls for multi-site fieldwork. This article discusses how such fieldwork was used to examine the contemporary restructuring of fresh food commodity chains between Africa and Europe, at a time of increasing European concerns about food safety and quality. Drawing on convention theory and actor-network theory for conceptual guidance, qualitative fieldwork was conducted at sites of production, import and export in ,anglophone' (Zambia,London) and ,francophone' (Burkina Faso,Paris) commodity chains. The article also discusses the challenges posed by multi-site research, especially in realms where secrecy and deception are standard tools of the trade. [source]

Synthesis of 2-Azabicyclo[3.2.2]nonane-Derived Monosaccharide Mimics and Their Evaluation as Glycosidase Inhibitors

HELVETICA CHIMICA ACTA, Issue 3 2006
Stephan Buser
Abstract The racemic 2-azabicyclo[3.2.2]nonanes 5 and 18 were synthesized and tested as , -glycosidase inhibitors. The intramolecular Diels,Alder reaction of the masked o -benzoquinone generated from 2-(allyloxy)phenol (6) gave the , -keto acetal 7 which was reduced with SmI2 to the hydroxy ketone 8. Dihydroxylation, isopropylidenation (,,12), and Beckmann rearrangement provided lactam 15. N -Benzylation of this lactam, reduction to the amine 17, and deprotection provided the amino triol 19 which was debenzylated to the secondary amine 5. Both 5 and 19 proved weak inhibitors of snail , -mannosidase (IC50,>,10,mM), Caldocellum saccharolyticum , -glucosidase (IC50,>,10,mM), sweet almond , -glucosidase (IC50,>,10,mM), yeast , -glucosidase (5: IC50,>,10,mM; 19: IC50,=,1.2,mM), and Jack bean , -mannosidase (no inhibition detected). [source]

Synthesis of N -Substituted (3S,4S)- and (3R,4R)-Pyrrolidine-3,4-diols: Search for New Glycosidase Inhibitors

HELVETICA CHIMICA ACTA, Issue 12 2004
Robert
N -Substituted (3S,4S)- and (3R,4R)-pyrrolidine-3,4-diols 9 and 10, respectively, were derived from (+)- L - and (,)- D -tartaric acid, respectively. Compounds 9k, 9l, and 9m with the N -substituents, BnNH(CH2)2, 4-PhC6H4CH2NH(CH2)2 and 4-ClC6H4CH2NH(CH2)2, respectively, showed modest inhibitory activities toward , - D -amyloglucosidases from Aspergillus niger and from Rhizopus mold (Table,1). Unexpectedly, several (3R,4R)-pyrrolidine-3,4-diols 10 showed inhibitory activities toward , - D -mannosidases from almonds and from jack bean (Table,3). N -Substitution by the NH2(CH2)2 group, i.e., 10g, led to the highest potency. [source]