Structure and performance of poly(γ-benzyl L-glutamate)-graft-poly(ethylene glycol) copolymer membrane

Poly(γ-benzyl L-glutamate)-graft-poly(ethylene glycol) (PBLG-graft-PEG) copolymer was synthesized by the ester exchange reaction of PBLG homopolymer with PEG chain. Chemical structure of PBLG-graft-PEG was confirmed by nuclear magnetic resonance (NMR) spectroscopy, morphology of copolymer membrane was investigated using scanning electron microscopy (SEM), and thermal transition behavior was studied using differential scanning calorimeter (DSC). It was revealed that PBLG-graft-PEG copolymer holds different structure and performance compared with PBLG homopolymer. The introduction of PEG chains not only decreases the melting point of PBLG segments in PBLG-graft-PEG, but also changes the morphology of PBLG segments. Influence of grafting ratio on chemical and mechanical properties of PBLG-graft-PEG copolymer membrane was studied.     

Effect of home processing on ascorbic acid and β-carotene content of spinach (Spinacia oleracia) and amaranth (Amaranthus tricolor) leaves

The present investigation was conducted to study the concentration of ascorbic acid and -carotene in spinach and amaranth leaves as affected by various domestic processing and cooking methods which included storage of leaves in polythene bags or without packing for 24 and 48 hours in refrigerator at 5 °C; at 30 °C in polythene bags; drying (sun and oven); blanching (5, 10, 15 min); open pan and pressure cooking. Ascorbic acid content of fresh leaves was 624.1 to 629.0 mg and -carotene content was 35.3 to 53.1 mg/100 g dry weight. The percent loss of ascorbic acid ranged from 1.1 to 6.3 and 55.3 to 65.9 while lower losses (0.0 to 1.3 and 1.5 to 2.1) of -carotene were observed in leaves stored in refrigerator and at 30 °C, respectively. A markedly greater reduction in ascorbic acid and -carotene was observed in dried, blanched and cooked leaves. The study recommended the storage of leaves in refrigerator, drying in oven, blanching for shorter time and cooking in pressure cooker for better retention of these two vitamins.     

Injury to apples and peaches at harvest from feeding by Halyomorpha halys (Stål) (Hemiptera: Pentatomidae) nymphs early and late in the season

Halyomorpha halys (Stål) (Hemiptera: Pentatomidae) is an invasive species that has become an important orchard pest in the Mid-Atlantic region of the US. Adults and nymphs feed on tree fruit. Feeding injury from adults has been characterized but the injury from nymphs has not been examined systematically. Since the four plant-feeding instars of H. halys (second through fifth) differ substantially in size, it is plausible that the effects of their feeding on fruit injury and injury expression may differ among them. We compared feeding injury at harvest from young nymphs (second plus third instars), older nymphs (fourth plus fifth instars), and adults that were caged on ‘Smoothee Golden’ apples and ‘Redhaven’ peaches in early June (peach and apple), late July (peach), and late August (apple). Individual apples and peaches were caged at fruit set and assigned to the following treatments (n = 28/treatment): 1) control (no H. halys), 2) young nymphs or 3) adults early in the season, and 4) young nymphs, 5) older nymphs or 6) adults later in the season. Fruit in each treatment were exposed to 3–4 young nymphs, two older nymphs or 1–2 adults placed in the cages for 96 h and evaluated for external and internal feeding injury within 36 h after harvest. No injury was recorded from unexposed peaches or apples. The percentage of injured fruit and number of injuries per fruit varied significantly among the exposed treatments. Early season feeding by young nymphs yielded the least injury to peaches and apples. In apples, the highest percentage of injured fruit and number of injuries per fruit were caused by late season feeding by adults. In peaches, early season adult feeding produced the highest percentage of injured fruit and injuries per fruit. More internal than external injury was recorded on peach and no such difference was observed on apple. The implications of these findings on H. halys management in fruit orchards are discussed.     

Identification and Function Analysis of enolase Gene NlEno1 from Nilaparvata lugens (St?l) (Hemiptera:Delphacidae)

The enolase [EC 4.2.1.11] is an essential enzyme in the glycolytic pathway catalyzing the conversion of 2-phosphoglycerate (2-PGE) to phosphoenolpyruvate (PEP). In this study, a full-length cDNA encoding α-enolase was cloned from rice brown planthopper (Nilaparvata lugens) and is provisionally designated as NlEno1. The cDNA sequence of NlEno1 was 1,851 bp with an open reading frame (ORF) of 1,305 bp and encoding 434 amino acids. The deduced protein shares high identity of 80–87% with ENO1-like protein from Hemiptera, Diptera, and Lepidoptera speices. The NlEno1 showed the highest mRNA expression level in hemolymph, followed by fat body, salivary gland, ovaries and egg, and showed trace mRNA levels in testis. The mRNA of NlEno1 showed up-regulated level in virulent N. lugens population Mudgo, IR56 and IR42 when compared with TN1 population. Injection of double-stranded RNA (dsRNA) of NlEno1 into the adults significantly down-regulated the NlEno1 mRNA level along with decreased eggs and offspring. Moreover, injection of NlEno1-dsRNA decreased mRNA level of Vitellogenin (Vg) gene. These results showed that the NlEno1, as a key glycolytic enzyme, may play roles in regulation of fecundity and adaptation of N. lugens to resistant rice varieties.     

Effects of temperature and pH on the inhibition of Bensulfuron-Methyl(BSM)

Bensulfuron-Methyl(BSM) is a highly active sulfonylurea herbicide that effectively controls most annual and perennial broadleaf or sedge weeds in paddy field. However, the activity of BSM is affected by several evironmental factors. Using corn seedlings as material, we found that under different temperatures     

Tetrodotoxins (TTXs) and Vibrio alginolyticus in Mussels from Central Adriatic Sea (Italy): Are They Closely Related?

Tetrodotoxins (TTXs), potent neurotoxins, have become an increasing concern in Europe in recent decades, especially because of their presence in mollusks. The European Food Safety Authority published a Scientific Opinion setting a recommended threshold for TTX in mollusks of 44 µg equivalent kg⁻¹ and calling all member states to contribute to an effort to gather data in order to produce a more exhaustive risk assessment. The objective of this work was to assess TTX levels in wild and farmed mussels (Mytilus galloprovincialis) harvested in 2018–2019 along the coastal area of the Marche region in the Central Adriatic Sea (Italy). The presence of Vibrio spp. carrying the non-ribosomal peptide synthetase (NRPS) and polyketide synthase (PKS) genes, which are suspected to be involved in TTX biosynthesis, was also investigated. Out of 158 mussel samples analyzed by hydrophilic interaction liquid chromatography coupled with tandem mass spectrometry (HILIC-MS/MS), 11 (7%) contained the toxins at detectable levels (8–26 µg kg⁻¹) and 3 (2%) contained levels above the EFSA safety threshold (61–76 µg kg⁻¹). Contaminated mussels were all harvested from natural beds in spring or summer. Of the 2019 samples, 70% of them contained V. alginolyticus strains with the NRPS and/or PKS genes. None of the strains containing NRPS and/or PKS genes showed detectable levels of TTXs. TTXs in mussels are not yet a threat in the Marche region nor in Europe, but further investigations are surely needed.     

Repellency of dimethyl disulfide to Apolygus lucorum (Meyer-Dür) (Hemiptera: Miridae) under laboratory and field conditions

The mirid bug, Apolygus lucorum (Meyer-Dür) (Hemiptera: Miridae), is a major pest of cotton, fruit trees, and many other crops in China. While previous trials have found relatively low infestation levels of A. lucorum in fields treated with the acaricide dimethyl disulfide (DMDS), its mode of action has not been determined. In this study, we assessed the insecticidal and repellent action of DMDS against A. lucorum under laboratory and field conditions. DMDS did not cause mortality of A. lucorum adults or nymphs at concentrations of 10.6 and 170.9 mg a.i./1. In Y-tube olfactometer tests, both male and female A. lucorum adults preferred clean air over DMDS odors. In choice and no-choice cage trials, feeding damage and the number of A. lucorum eggs were lower on mungbean plants treated with DMDS than on control plants. Under field conditions, adult A. lucorum density was lower in DMDS-treated mungbean and cotton fields than in untreated fields, and this effect lasted 6 d, but nymph populations were not affected. Under field conditions, adult A. lucorum were repelled at a distance of up to 6 m from DMDS-sprayed cotton plants for 6 d after application. This study demonstrates the non-lethal repellent action of DMDS against adult A. lucorum and suggests its potential inclusion in integrated pest management (IPM) schemes.     

Vitamin C and quercetin modulate DNA-damaging effect of N-methyl-N′-nitro-N-nitrosoguanidine (MNNG)

The effects of natural compounds, vitamin C and quercetin, present in fruitsand vegetables, on the DNA damaging activity of a food carcinogen N-methyl-N-nitro-N-nitrosoguanidine (MNNG) were examinedusing the comet assay. Vitamin C, at a concentration of 50 M,inhibited MNNG-induced DNA damage in human lymphocytes. Quercetin,up to a concentration of 10 M, increased the extent of DNA damage,but at concentrations above 10 M decreased damage below controlvalues. Furthermore, quercetin had a strong antioxidant activity againstoxidative damage evoked by H₂O₂ at 10 M. The resultsobtained suggest that vitamin C and quercetin may have anti- orpro-oxidative properties depending on the state of the cell.     

Do barley and wheat (bread and durum) differ in grain weight stability through seasons and water-nitrogen treatments in a Mediterranean location?

Under Mediterranean environments, farmers usually prefer to sow barley rather than wheat as it is generally believed that barley yields more under stressful conditions. As terminal stresses such as high temperature and water are common constraints in Mediterranean regions, higher grain weight stability may confer a clear advantage in order to maintain higher yields. The objective of the present study was to compare the stability in terms of grain weight and its components for barley, bread wheat, and durum wheat, exploring a wide range of nitrogen and water availabilities in experiments conducted in a Mediterranean region. Grain weight ranged from 23.8 to 47.7 mg grain⁻¹, being higher for durum wheat than barley and bread wheat. Durum wheat presented higher variability both in maximum grain filling rate and duration of grain filling period than bread wheat or barley. The three species responded similarly in terms of grain nitrogen content to changes in the environmental conditions explored. It is concluded that in terms of grain weight barley is as stable as bread wheat. However, durum wheat presented a lower stability than barley and bread wheat.     

The Biological Activities and Chemical Composition of Pereskia Species (Cactaceae)—A Review

The exploration of nature as a source of sustainable, novel bioactive substances continues to grow as natural products play a significant role in the search for new therapeutic and agricultural agents. In this context, plants of the genus Pereskia (Cactaceae) have been studied for their biological activities, and are evolving as an interesting subject in the search for new, bioactive compounds. These species are commonly used as human foodstuffs and in traditional medicine to treat a variety of diseases. This review focuses on the bioactivity and chemical composition of the genus Pereskia, and aims to stimulate further studies on the chemistry and biological potential of the genus.     

Electrical conductivity and chromic behavior of poly (3-methylthiophene) — coated polyester fabrics

Electrically conductive substrates with chromic behavior are prepared using conductive polymer coating of the substrate. Poly (3-methylthiophene) (P3MT) — coated polyester fabric with specific electrical and chromic properties, for instance electrochromic and piezochromic behavior, was successfully obtained by chemical polymerization with the help of continuous and speed stirring technique. The effect of polymerization time, temperature and oxidant concentration on conductivity of the P3MT-coated fabric was studied. The presence of P3MT particles on the surface of the coated substrate was confirmed by scanning electron microscopy (SEM), fourier transform infrared (FTIR) and UV-Vis spectroscopy, electrical surface resistivity, pressure and applied voltage dependence visible reflectance spectrophotometer measurements, and X-ray diffraction (XRD) analysis. The blue shift of c95 nm in wavelength of maximum absorption observed in the reflectance spectra of coated polyester fabric. Under high pressure, the P3MT-coated polyester fabric demonstrated piezochromism. The coated substrate also showed electrochromic behavior under an electrical applied voltage of 12 V.     

In vitro fermentation kinetics and end-products of cereal arabinoxylans and (1,3;1,4)-β-glucans by porcine faeces

Purified and semi-purified polysaccharides characteristic of cereals were fermented in vitro with a pig faecal inoculum, using the cumulative gas production technique, to examine the kinetics and end-products of fermentation after 48 h. It was shown that arabinoxylan and mixed linkage (1,3;1,4) β-glucan were rapidly fermented if soluble, while less soluble substrates (insoluble arabinoxylan, maize and wheat starch granules, and bacterial cellulose) were more slowly fermented. Relevant monosaccharides were fermented at very similar rates to soluble polymeric arabinoxylan and β-glucan, showing that depolymerisation was not a limiting step, in contrast to some previous studies. Bacterial cellulose is shown to be a useful model substrate for fermentation of plant cellulose which is difficult to obtain without harsh chemical treatments. Fermentation end-products were related to kinetics, with slow carbohydrate fermentation resulting in increased protein fermentation. Ratios of short-chain fatty acid products were similar for all arabinoxylan and β-glucan substrates.     

Effects of Cultivar and Environment on β-(1,3)-(1,4)-D-glucan Content and Acid Extract Viscosity of Spanish Barleys

The acid extract viscosities and β-glucan contents of ten two- and six-rowed barley cultivars grown at seven locations in three consecutive years in Spain were studied in the present work. The viscosities varied from 2·4 to 24·8 centistokes (cSt) and the mean value was 6·4 cSt. The average β-glucan content of barleys determined by HPLC was 3·5% with a range of 1·9–5·5%. Significant differences were found in both β-glucan content and acid extract viscosity between different cultivars, locations and years. The β-glucan contents and viscosities of winter cultivars were higher than those of spring. Cvs. Barbarrosa and Hatif de Grignon were the genotypes with the highest values for both parameters, while cv. Beka had the lowest viscosity and β-glucan content. Environmental factors influenced both parameters. The acid extract viscosities of barleys were correlated negatively with the amount of precipitation (r=−0·754;P<0·05). Barleys grown in wet and rainy areas (Girona and La Coruña) had lower viscosity values.     

Workshop on Simulation and Systems Analysis for Rice Production(SARP) held at CNRRI

SARP Workshop on risk analysis of agroecological zonation and optimization of crop rotation was held at CNRRI's research center on 24—27 Oct, 1995. Experts from Philippines, India, China, and IRRI were present in the workshop. Participants exchanged the research results on the field of land use, soil erosion. optimization of rice—wheat, rice—peanut, rice—corn cropping system in the different environments, risk analysis of rice based cropping system, nitrogen balance in rice based cropping system with system approach, demonstrated models used in their studies, and discussed the ongoing cooperative research.     

大麦(综述)

大麦在世界谷物生产中,虽居小麦、水稻和玉米之后,但其栽培的环境比哪一种都更为广泛.从分类学上说,目前一般认为,所有大麦都是一个种(Hordeum vugare L. emend. Bowden)这个种有多种多样的类型,但穗子基本上只有六棱和二棱两种.六棱型的每节中央和两侧小花都是可育的;二棱型的只有中央小花可育.大麦还有野生植物或杂草的形状,     

Does relative time of emergence affect stand composition and yield in a grass–legume mixture? Kura clover (Trifolium ambiguum)–meadow bromegrass (Bromus biebersteinii) and Kura clover–orchardgrass (Dactylis glomerata) mixtures

Establishing Kura clover (Trifolium ambiguum) in mixtures with grass species is challenging, because slow growth of clover seedlings results in low competitive ability. This study examined establishment success by altering time of seeding of the grass component to reduce competition with Kura clover seedlings. Two trials, one of Kura clover–meadow bromegrass (Bromus biebersteinii) and the other Kura clover–orchardgrass (Dactylis glomerata) mixtures were planted in Edmonton, Alberta. Grasses were seeded at the same time as the clover, or introduced when the clover reached one true leaf or three true leaves, in the autumn of the planting year or the following spring. Species composition varied significantly between treatments. When sown at the same time, Kura clover contributed 31 and 14% of yield in the establishment year when sown with meadow bromegrass and orchard grass, respectively. Delaying grass sowing until Kura clover had one or three leaves gave a higher percentage of Kura clover compared with planting at the same time. Autumn and spring grass sowing resulted in stands of 78 and 80% clover with meadow bromegrass, and 74 and 67% clover with orchardgrass. Altering the competitive advantage of the grass species to produce a more balanced mixture was successfully achieved by delaying seeding of the grass relative to Kura clover. A long interval before introducing the grass (autumn or following spring), was not successful as established Kura clover seedlings have an increased competitive ability.