Biochemical basis of insect resistance in inged bean (Psophocarpus tetragonolobus) seeds

Mature seeds of the inged bean (Psophocarpus tetragonolobus) are toxic to developing larvae of a range of cosmopolitan storage Bruchidae of economic importance, including the copea seed eevil, Callosobruchus maculatus. Insect feeding trials ere carried out in hich protein fractions from seeds of inged bean ere incorporated at a range of concentrations into artificial seeds, and their effects upon development of C maculatus determined. Both albumin and globulin fractions ere toxic to the developing larvae and their toxicity correlated ith their haemagglutinating activity. Assay of Psophocarpin A, B and C fractions demonstrated Psophocarpin B to be the most insecticidal and to contain the highest haemagglutinating activity. Purified basic seed lectin as highly insecticidal to C maculatus larvae, ith an LC₅₀ value of c. 3·5 g kg^?1. The physiological level of this protein in inged bean seeds is sufficient to account for their resistance to attack by C maculatus. inged bean trypsin inhibitor as also purified and tested in artificial seeds against C maculatus. Hoever, even at concentrations in excess of tice the physiological concentration it had no deleterious effects upon development.     

Presence of two saponins in faba bean (Vicia faba L.) seeds

From faba bean (Vicia faba L.), two new saponins were isolated by Sephadex LH-20 gel filtration, ODS column chromatography and semi-preparative HPLC. Their molecular weights determined by FAB-MS were 978 and 962, respectively. Results of TLC and FTIR analyses showed that these compounds are similar to soya saponin group B. The presence of separated saponins was confirmed by TLC for seeds of four cultivars of faba bean.     

Mapping of maize storage losses due to insect pests in central Mexico

Postharvest grain storage are a major problem in Mexico, influencing the economy, livelihoods, and food security of most farmers. At present, very limited information is available on postharvest maize losses and the associated insect pests in Mexico. Therefore, the objective of this study was to quantify and map maize storage losses in Central Mexico (State of Mexico) to analyze the effects of major pests in the different regions and to provide useful data to policymakers and local stakeholders. The study was conducted with 120 farmers dispersed across all regions of maize production in the State of Mexico. Storage losses were quantified using standardized maize samples that harvest, stored for a year, and sampled periodically. These data, together with geographic coordinates, were integrated into a geographic information system (GIS) to generate maps of maize storage damage and weight losses. The resulting maps show that in the southern region of the State of Mexico the standardized samples exhibited the highest maize losses after a one-year storage period, with an average of 76% loss and 100% grain damage, followed by the northern region, with an average of 18% loss and 52% damage. The eastern region reported 10% loss and 16% damage, whereas the Central region showed 5% loss and 14% damage. The main storage pests identified displayed localized geographic distributions, with the maize weevil, Sitophilus zeamais, being mainly localized in the South, the larger grain borer, Prostephanus truncatu, in the East and North, and the angoumois grain moth, Sitotroga cerealella, in the Northeast and Central regions. Thus, these maps are robust tools that will help towards improving storage facilities and increasing food security for small-scale farmers.     

Laboratory evaluation of natural embelin as a grain protectant against some insect pests of wheat in storage

The effectiveness of natural embelin isolated from berries of Embelia ribes is discussed as a grain protectant for wheat in storage. More than 50% mortality of Sitophilus oryzae (L.) adults was observed in wheat grains when treated at 0.025% concentration. The F1 progeny was reduced in treatments. However, productivity (progeny/21 adult-days) in treatments was not significantly different from controls. In the case of Rhyzopertha dominica (F.), there was 50% adult mortality at 0.025% concentration after 1 day and 3 months of storage, and both progeny and productivity were reduced significantly at all the concentrations. After 8 months of storage, only the highest concentration of 0.1% exhibited appreciable adult mortality, yet the F1 progeny and productivity were significantly low in all the concentrations of embelin. Against larvae of Corcyra cephalonica (Stainton) and Ephestia cautella (Walker), 0.0125% concentration retained its effectiveness after 8 months, while higher concentrations of 0.05 and 0.1% offered good protection against Trogoderma granarium Everts larvae. Embelin in the present study did not show any contact toxicity to adults of S. oryzae or R. dominica. The treatment did not have any adverse effect on germination of wheat seeds. In general, the effectiveness of embelin tested against five insect species was C. cephalonica > E. cautella > R. dominica > T. granarium > S. oryzae.     

Extraction of favism‐inducing agents from whole seeds of faba bean (Vicia faba L var major)

The objective of the present study was to establish a suitable procedure by which favism‐inducing glycosides vicine and convicine could be completely removed from whole seeds of faba beans without distorting their shape or reducing their nutritive value. Detoxification procedures carried out were extraction by water or, 10 g l^?1 acid solutions (acetic, citric and phosphoric acid) using stepwise or continuous soaking procedures. Three cultivars of the beans were used in the study. In the stepwise soaking procedures, the seeds were soaked in either water or acid solution at 40 °C for different periods while in the continuous flow techniques, the solutions were constantly passed through a seed reservoir under different time–temperature–flow rate conditions. Extraction of vicine and convicine increased with increasing temperature and period of soaking and/or continuous flow of soaking solutions. Neither stepwise soaking nor autoclaving could effectively remove the favism factors from the whole seeds. The best results were obtained with continuous flow soaking in tap water, giving vicine‐ and convicine‐free seeds. The protein contents of treated seeds were only slightly affected and their physical structure remained intact. Thus, it was concluded that the latter procedure was the method of choice for detoxification of dry whole seeds. Copyright © 2005 Society of Chemical Industry     

茉莉酸甲酯诱导烟草抗虫的有效浓度和持效期

为阐明茉莉酸甲酯（MeJA）诱导烟草抗虫机制,用50 μmol/L和150 μmol/L的MeJA乙醇水溶液喷洒烟苗,24 h和48 h后取叶片分别喂食棉铃虫和甜菜夜蛾,每隔6 h监测取食量及体重变化,同时通过Folin-Ciocalteu比色法检测烟叶总多酚含量变化,并利用组织化学染色法统计分泌蔗糖酯的腺毛数。结果显示:（1）对于棉铃虫,50 μmol/L和150 μmol/L的MeJA喷施烟苗24 h~48 h后,试虫取食量和体重增加量均显著低于对照,而对于甜菜夜蛾,仅150 μmol/L MeJA处理烟苗24 h后引起试虫取食量和体重增加量明显降低;（2）MeJA诱导烟叶总多酚含量增加,增加量与MeJA浓度呈正相关;（3）MeJA导致烟叶分泌蔗糖酯的腺毛密度降低,腺毛密度与MeJA浓度呈负相关。MeJA诱导烟草抗虫具有一定的持效期且抗虫效果受其浓度影响,而总多酚含量增加和代谢改变或许是烟草产生抗虫性的部分原因。      

Evolution of soluble carbohydrates during the development of pea, faba bean and lupin seeds

Seeds of pea (Pisum sativum L. cv. Ergo), faba bean (Vicia faba ssp. minor Harz., cv. Tibo) and yellow pea lupin (Lupinus luteus L. cv. Juno) were sampled at different days after flowering (DAF) and their content of soluble carbohydrates was determined: Analysis of samples showed thatmyo-inositol, fructose, glucose, galactose and sucrose were found in high abundance early in development and their content decreased gradually during maturation. -Galactosides, which includes the content of raffinose, stachyose and verbascose, started to appear later in seed development, at 37 DAF in peas, 40 DAF in faba beans and 45 DAF in lupins. Their accumulation increased considerably during seed growth, and the maximum content was obtained in mature seeds; 3.8% in peas, 4.5% in faba beans and 10.4% in lupins. Results obtained for these sugars during seed development were fitted to modelling curves in order to predict sugar content at different development stages.     

Effect of ripening stage on thiamin and riboflavin levels in lupin, pea and faba bean seeds

 Seeds of yellow pea lupin (Lupinus luteus L., cv. Juno), pea (Pisum sativum L., cv. Ergo) and faba bean (Vicia faba sp. minor Harz., cv. Tibo) were harvested at different stages of seed maturity. Changes in thiamin and riboflavin levels during growth and maturation were studied. The results obtained showed that thiamin and riboflavin were found in high abundance early in the development of lupins and peas, but that their content decreased during maturation. The thiamin content of faba bean seeds increased from 33 to 47 days after flowering (DAF), then a decrease was observed until 61 DAF; however, no significant differences between these levels in faba bean seeds harvested from 61 to 89 DAF were found. The riboflavin content of faba beans increased after 54 DAF, and no significant changes were observed between then and 89 DAF. The thiamin and riboflavin contents in lupin, pea and faba bean seeds during development were fitted to modelling curves in order to predict the vitamin content at different stages of maturity. Received: 17 July 1997     

西瓜子破壳力学特性的影响因素

目的：对西瓜子破壳载荷的影响因素进行研究，为其破壳加工工艺提供理论依据；方法：设计西瓜子挤压破壳试验，对影响西瓜子破壳载荷的不同因素：加载位置、加载速率、西瓜子宽度和含水率进行研究，求出回归方程并进行方差分析；结果：加载位置应位于西瓜子最大宽度两侧；西瓜子的含水率是影响破壳载荷的显著因素，适当增加可以减小破壳载荷并降低能耗；根据西瓜子宽度设置挤压间隙，增大加载速率可提高生产效率，这2个因素都不影响破壳载荷。     

Effect of ripening stage on thiamin and riboflavin levels in lupin, pea and faba bean seeds

 Seeds of yellow pea lupin (Lupinus luteus L., cv. Juno), pea (Pisum sativum L., cv. Ergo) and faba bean (Vicia faba sp. minor Harz., cv. Tibo) were harvested at different stages of seed maturity. Changes in thiamin and riboflavin levels during growth and maturation were studied. The results obtained showed that thiamin and riboflavin were found in high abundance early in the development of lupins and peas, but that their content decreased during maturation. The thiamin content of faba bean seeds increased from 33 to 47 days after flowering (DAF), then a decrease was observed until 61 DAF; however, no significant differences between these levels in faba bean seeds harvested from 61 to 89 DAF were found. The riboflavin content of faba beans increased after 54 DAF, and no significant changes were observed between then and 89 DAF. The thiamin and riboflavin contents in lupin, pea and faba bean seeds during development were fitted to modelling curves in order to predict the vitamin content at different stages of maturity. Received: 17 July 1997     

Accumulation and quality of storage protein in developing cowpea,mung bean and soya bean seeds

This study was carried out to compare the time course of laying down seed storage protein in three legumes viz: cowpea (Vigna unquiculata), mung bean (Phaseolus aureus) and soya bean (Glycine max) planted in two replications. Pods were harvested periodically during seed maturation and studied for changes in fresh and dry weights, total sulphur, total nitrogen and protein content. At early stages of development crude protein formed about one-third of dry weight in the legumes but decreased to about one-quarter at maturity. The total sulphur which formed a substantial amount of the sulphur amino-acids in mature seeds did not change much in mung bean and cowpea but increased by about 24% from 20 to 69 days after flowering (DAF) in soya bean. Storage protein accumulation was very rapid between 10 and 14 DAF (10.4% day^?1) in mung bean, 7 and 14 DAF (12.9% day^?1) in cowpea and between 20 and 30 DAF (9.4 day^?1) in soya bean. Thereafter, protein accumulation declined slightly and gradually approached zero at time of seed maturity. The sulphur-to-nitrogen ratios gradually increased with maximum values in the mature seeds. Although seed protein content and quality (on S/N ratio basis) were highest in soya bean, accumulation of storage protein seemed to be faster in cowpea than mung bean and soya bean during seed maturation.     

Effects of PICS bags on insect pests of sorghum during long-term storage in Burkina Faso

The PICS bags, originally developed for cowpea storage, were evaluated for sorghum (Sorghum bicolor) preservation. Batches of 25 kg of sorghum grain were stored in 50 kg PICS or polypropylene (PP) bags under ambient conditions for 12 months and assessed for the presence of insect pests and their damage, seed viability and, oxygen and carbon dioxide variations. The grain was incubated for 35 days to assess whether any insects would emerge. After six months of storage, oxygen levels decreased in the PICS bags compared to polypropylene bags. After 12 months of storage, only two pests, Rhyzopertha dominica and Sitophilus zeamais were found in the PICS bags. However, in PP bags there were additional pests including Tribolium castaneum and Oryzeaphilus mercator and Xylocoris flavipes. Grain weight loss and damage caused by these insects in the PP bags were significantly higher compared to those stored in PICS bags. Germination rates of sorghum grains stored in PP bags decreased significantly while no changes were observed in grains stored in PICS bags when compared to the initial germination. After the incubation post storage period, there was a resurgence of R. dominica in sorghum grains from PICS bags but the population levels were significantly lower compared to polypropylene bags. PICS bags preserved the quality and viability of stored sorghum grains and protected it from key insect pests. The PICS technology is effective for long-term sorghum storage but the potential resurgence of insects in low-oxygen environment calls for further research.     

Cooking quality of faba bean after storage at high temperature and the role of lignins and other phenolics in bean hardening

Selected physical and chemical characteristics of faba beans (Vicia faba L.) cv. Fiesta were studied after 12 months storage at 5, 15, 25, 37, 45 or 50 °C (±2 °C) in relation to the hard-to-cook phenomenon. In comparison with control (seeds stored at 5 °C), seeds stored at 15 and 25 °C demonstrated non-significant (p?0.05) changes in most of the physical and chemical characteristics including hydration and swelling coefficients, acid detergent fibre, lignin and tannin contents, whereas seeds stored at ?37 °C demonstrated significant changes (p?0.05). Solutes and electrolytes leaching after 18 h soaking substantially increased with increased temperature. Faba bean hardness tested by the hard-to-cook test also increased substantially with increased storage temperature. After 8 h soaking followed by 2 h cooking, the puncture force required for seeds stored at 5 °C was 3.3 N seed⁻¹ whereas seeds stored at 50 °C required a much higher puncture force of 15.2 N seed⁻¹. There was a high negative correlation (r²=0.98) between storage temperature and cooking ability of faba bean. Substantial increases in acid detergent fibre and lignin contents occurred with increased storage temperatures. There was a three-fold increase in lignin content of faba bean stored at 50 °C compared to those stored at 5 °C and it was correlated with bean hardness (r²=0.98). Storage at high temperatures for 12 months led to a substantial reduction in total free phenolics especially in the testa and there was a greater reduction with increasing storage temperature. Reduction in free phenolics was negatively correlated (r²=0.75) with bean hardness.     

Impact of storage structures on moisture content,insect pests and mycotoxin levels of maize in Ghana

Insect pests and fungal pathogens can cause extensive product losses and pose health risks in sub-Saharan Africa. In this experiment, maize stored as de-husked cobs or shelled maize in a ventilated crib and a metal bin, and in bags in warehouses, was monitored monthly in Ghana from October of 2015 to December of 2015 (the major season) and from January to April of 2016 (the minor season). Temperature, moisture content, insect pests, and associated damage were assessed monthly, and samples were taken in October, December, January, and April for mycotoxin analyses. Moisture content, which ranged from 9 to 15% during the year was occasionally greater in the bin and warehouse compared to the crib, and greater in months associated with the major season compared to other months. Temperatures varied with season but were generally warmer in the bin compared to the warehouse and crib. The predominant insect collected was Sitophilus zeamais (Motschulsky), with the lowest populations in the crib, but in each structure the populations were about 10x greater in the major season compared to the minor season. Sitotroga cerealella (Olivier) was the second most-prevalent species, but populations of this species were greater in the crib compared to the bin or warehouse. Scattered populations of other stored product insects were collected from the maize samples and in pheromone traps. Percentage insect damaged kernels (IDK) and weight loss were also greater in samples from months where S. zeamais was present. Aflatoxin was above 10 ppb only in the warehouse in December, while fumonisin levels in all the storage structures were <0.5 ppm for all months. Results show that maize stored during the major season in Ghana is at risk from insect damage, and metal bins could be utilized more frequently for storage.     

Gelation of a broad bean (Vicia faba L. minor) protein fraction (prepared at pH 2) in dependence on some influencing factors

A protein fraction is prepared from broad bean protein isolate at pH 2 which forms gels in the acid pH range. The gels are fluid at high temperature and become strength when cooling. The gel strength increases with increasing pH, with increasing heat treatment, and with increasing protein concentration. Addition of calcium and dextrose sirup increases the gel strength whereas sucrose decreases it. The transparency of the gels decreases with increasing pH.     

影响立方氮化硼复合片耐磨性的工艺因素研究

通过大量的实验,对立方氮化硼复合片的工艺因素进行了分析。结果表明:cBN的粒径和原料的真空净化处理是影响立方氮化硼复合片耐磨性的主要工艺因素。选用T i-S i-B作为粘接剂,用细颗粒立方氮化硼在5.0~7.0GPa,1673~1873K的条件下[1],合成出磨耗比大于1∶11000立方氮化硼复合片。     

Gel properties of a protein fraction of Vicia faba in dependence on some influencing factors

The shear modulus of Vicia faba protein gels formed by thermal denaturation can be lowered by increasing the pH value and the sunflower oil concentration, it can be increased by increasing concentrations of NaCl, CaCl₂, AlCl₃, glucose, sucrose, and starch. These changes of the shear modulus are connected with a shift of the ratio of the plastic component of the gels to an elastic one.     

Abiotic and biotic factors affect efficacy of chlorfenapyr for control of stored-product insect pests

Laboratory bioassays were conducted to assess pyrole chlorfenapyr as a potential grain protectant against adults of Rhyzopertha dominica, Sitophilus oryzae, Prostephanus truncatus, Tribolium confusum, and Liposcelis bostrychophila. Factors such as dose (0.01, 0.1, 0.5, 1, 5, and 10 ppm), exposure interval (7 and 14 days), temperature (20, 25, and 30°C), relative humidity (RH; 55 and 75%), and commodity (wheat, maize, barley, and paddy rice) were evaluated. Progeny production was assessed after 74 days of exposure. For L. bostrychophila and T. confusum the increase of dose increased mortality. After 7 or 14 days of exposure, mortality was low at doses of ≤ 1 ppm and did not exceed 23 or 36%, respectively, for L. bostrychophila or 13 or 58%, respectively, for T. confusum. After 14 days of exposure, mortality of S. oryzae at 30°C and 75% RH was 82.2%. Mortality of P. truncatus was considerably higher than that of the other species. At 0.5 ppm, mortality exceeded 81% after 7 days of exposure and 91% after 14 days of exposure. Progeny production of L. bostrychophila was extremely high. Very few progeny were found for T. confusum. For S. oryzae, offspring emergence was high, except at 20°C and 55% RH. For P. truncatus, progeny production in the treated maize was not avoided, even at 10 ppm. In the case of S. oryzae, at 0.1 ppm and after 14 days of exposure, mortality in wheat was higher than in the other three commodities. For R. dominica, mortality was low at 0.1 and 1 ppm for paddy rice but reached 74.4% in barley after 14 days of exposure. For T. confusum, mortality was low at 0.1 and 1 ppm in all commodities. For progeny production counts, for S. oryzae or R. dominica, adult emergence was higher in paddy rice than in the other three commodities. Finally, overall T. confusum progeny was low. Chlorfenapyr efficacy varied remarkably among the combinations tested, and it may be a viable grain protectant in combination with other insecticides.     

Effect of nutritional status of faba bean (Vicia faba L.) on protein solubility profiles

A field experiment was carried out to study the effect of mycorrhizal inoculation. phosphorus and sulphur fertilization, under two water regimes, on protein solubility fractions of faba bean. The major protein fraction of faba bean was the globulin fraction that ranged from 69.5 to 78.1%. Phosphorus treatment significantly (P⩽0.05) increased the globulin fraction of faba bean seeds in the wet treatment but significantly (P⩽0.05) decreased it in the dry treatment. All fertiliser treatments significantly (P⩽0.05) increased the albumin fraction in the wet treatment, whereas only treatments of mycorrhiza, mycorrhiza+sulphur and mycorrhiza+phosphorus+sulphur significantly increased it in the dry treatment compared to control. With the exception of the treatment mycorrhiza+sulphur, all other fertilisation treatments showed prolamin contents of faba bean seeds, similar to that of the control in the wet treatment. The G₃-glutelin fraction of faba bean ranged from 8.9 to 14.4%. Treatments with sulphur, mycorrhiza and mycorrhiza+sulphur significantly increased the G₃-glutelin fraction, whereas phosphorus and mycorrhiza+phosphorus treatments significantly decreased it. The insoluble protein (residue) of faba bean ranged from 1.8 to 3.4%. Generally, fertiliser treatments significantly increased the insoluble protein in the wet treatment. With the exception of treatments mycorrhiza and mycorrhiza+sulphur, all other fertiliser treatments significantly increased the insoluble protein content in the dry treatment. Water regime significantly (P⩽0.05) affected the protein fractions.     

Effectiveness of hermetic containers in controlling paddy rice (Oryza sativa L.) storage insect pests

Naturally infested paddy rice was used to compare the effectiveness of polypropylene bags and hermetic storage containers over 12 months of storage in a warehouse. Insect pest identification as well as the infestation level, percentage of damaged grain, weight loss, and moisture content were evaluated. Five insect species associated with stored rice were identified during the storage period, namely lesser grain borer (Rhyzopertha dominica), red flour beetle (Tribolium castaneum), rice/maize weevil (Sitophilus spp.), angoumois grain moth (Sitotroga cerealella) and flat grain beetle (Cryptolestes ferrugineus). The lesser grain borer was the most predominant species with an average incidence above 70% after twelve months of storage, followed by the rice/maize weevil with an incidence of 17%. When compared to hermetic storage containers, polypropylene bag showed the highest mean infestation level with 233.3 individuals/kg after six months of storage, representing about 8-fold of the number of insects recorded in hermetic containers after six months of storage. In polypropylene container, the percentage of damaged grain and weight loss increased significantly achieving a maximum of 6.98% and 5.56% respectively, whereas using hermetic containers the highest percentage of damaged grain reached was 3.24% in polyethylene drum and the weight loss was 1.62% in GrainSafe bag. The results from the study show that the use of hermetic storage containers is a green alternative for safe storage of paddy rice, for 12 months without application of pesticides, bringing multiple advantages for smallholder farmers, lever food security and income generation for smallholder farmers and rice milling companies.