Nematicidal efficacy of isothiocyanates against root-knot nematode Meloidogyne javanica in cucumber

Isothiocyanates (ITCs), a series of new nematicides of the -NCS group, were evaluated for their efficacy against root-knot nematode Meloidogyne javanica. Of the compounds tested, AllylITC, AcITC, EtITC, BzTC, BzITC, 1-PEITC and 2-PEITC showed in vitro irreversible nematicidal activity against second-stage juveniles of M. javanica, following exposure for 72 h at concentrations as low as 5 μg mL⁻¹. When exposed to AllylITC, AcITC and EtITC at lower concentrations, motile juveniles also became irreversibly immobile in 3 days, with a LC₅₀ value at 2.76, 2.53 and 3.05 μg mL⁻¹, respectively. In the pot experiments, 1.0 ml AllylITC and 1.1 ml AcITC per kg of soil controlled M. javanica, similarly to or better than metam sodium at its recommended dose. Similar results were obtained in the field experiments using 1.0 kg AllylITC or 1.0 kg AcITC ha⁻¹. Based on the results of this study, AllylITC and AcITC have potential to be used as new bio-fumigant nematicides.     

Studies on the utilization of Hura crepitans L. seed oil in the preparation of alkyd resins

The utilization of Hura crepitans seed oil in the formulation of alkyd resins was investigated using a two-stage alcoholysis-polyesterification method. The percentage yield of the oil was 36.4%; and the physicochemical characterization revealed that the seed oil is an unsaturated semi-drying oil. The fatty acid profile of the oil showed that it contains linoleic acid (81.6%) as the most abundant fatty acid, and two other fatty acids: palmitic acid (16.92%) and stearic acid (1.76%). Short (I), medium (II) and long (III) oil alkyds were synthesized using the oil, glycerol and phthalic anhydride in different ratios. Properties of the three prepared samples of H. crepitans seed oil alkyds having oil content of 30% (I), 50% (II), and 65% (III) were evaluated. The alkyd resins synthesized compared favourably with the commercially available alkyd resin. The presence of unsaturation in the oil was confirmed by infra-red peak at 2930 cm⁻¹ attributed to CC stretch. The infra-red peaks of the sample also compared well with that of the commercial sample indicating that H. crepitans seed oil has been successfully converted to alkyd resin. Evaluation of prepared alkyds by determination of acid values, solubility in butanol and toluene, resistance of dry film to acid, alkali and water, and drying time revealed that H. crepitans seed oil is a potential raw material for the coating industry.     

Characteristics, chemical composition and utilisation of Albizia julibrissin seed oil

The physicochemical characteristics, fatty acid and triacylglycerol compositions, DSC profile and UV/vis spectrum of oil extracted from Albizia julibrissin seeds were determined in this study. The oil content and the moisture of the seeds were 10.50% and 1.56%. The free fatty acid, the peroxide value, the p-anisidine value, the saponification value, the iodine value were 2.54%, 6.61 mequiv. O₂/kg of oil, 1.98, 190.63 (mg KOH/g) and 111.33 (g/100 g of oil), respectively. The specific extinction coefficients K₂₃₂, K₂₆₈ were 7.55 and 0.96, respectively. Linoleic acid (C_18:2, 58.58%), palmitic acid (C₁₆, 13.86%) and oleic acid (C_18:1, 10.47%) were the dominant fatty acids in the A. julibrissin seed oil. LLL (36.87%), OLL (21.62%), PLL (16.69%) and PLO + SLL (8.59%) were the abundant triacylglycerol representing > 83% of the seed oil (L: linoleic, O: oleic, P: palmitic, S: stearic). The DSC melting curves reveal that: melting point = −14.70° C and melting enthalpy = 54.34 J/g. A. julibrissin seed oil showed some absorbance in the UV-B and UV-C ranges. The results of the present analytical study show that A. julibrissin is a promising oilseed crop, which can be used for making soap, hair shampoo and UV protectors. Furthermore, the high level of unsaturated fatty acids makes it desirable in terms of nutrition.     

Effects of crude seed extracts of Annona atemoya and Annona squamosa L. against the cabbage looper, Trichoplusia ni in the laboratory and greenhouse

Antifeedant, growth inhibitory and toxic effects of crude seed extracts of Annona squamosa and Annona atemoya from Fazenda Viveiro Bona, Parasisópolis – Minas Gerais, Brazil, were evaluated against the cabbage looper, Trichoplusia ni (Hübner) (Lepidoptera: Noctuidae) using different bioassays. Crude methanolic seed extracts deterred feeding of third instar T. ni larvae in a leaf disc choice bioassay. A. squamosa was ∼10 times more active as a feeding deterrent than A. atemoya (DC₅₀ = 2.3 mg/ml vs. 20.1 mg/ml). A. squamosa was ∼three times more active as a growth inhibitor than A. atemoya (EC₅₀ = 38.0 ppm vs. 117.0 ppm). Methanolic seed extracts of A. squamosa and A. atemoya were toxic to third instar T. ni larvae both through topical and oral application. A. squamosa was more toxic through feeding (LC₅₀ = 167.5 ppm vs. 382.4 ppm) whereas, A. atemoya exerted greater toxicity via topical application (LC₅₀ = 301.3 μg/larva vs. 197.7 μg/larva). Both A. squamosa and A. atemoya extracts reduced leaf area consumption and larval growth in a greenhouse experiment. Our results indicate that both A. squamosa and A. atemoya have potential for development as botanical insecticides, especially for local use in Brazil.     

Genetic analysis of field resistance to tan spot in spring wheat

Tan spot, caused by Pyrenophora tritici-repentis (Died.) Drechs., is an important constraint to wheat (Triticum aestivum L.) yield in many countries. Since the inheritance of field resistance to tan spot is poorly understood, this study was conducted to determine the genetic control of resistance in the field. Resistance was measured as disease severity caused by P. tritici-repentis race 1 in four crosses involving five wheat parents: parent 1 (P₁) = catbird; parent 2 (P₂) = Milan/Shanghai-7; parent 3 (P₃) = Alondra/Coc//Ures; parent 4 (P₄) = Bcb//Dundee/Gul/3/Gul); parent 5 (P₅) = ND/VG9144//Kal/BB/3/Yaco/4/Chil. P₁, P₂ and P₃ were resistant and P₄ was moderately resistant, whereas P₅ was susceptible to tan spot. The F₂-derived F₃ families and the parents were field evaluated at El Batán, Mexico, in 1996. When all the plants within a F₃ family expressed low levels of disease severity similar to that of the resistant parent it was classified resistant (R), otherwise the progeny was classified as susceptible (S). The progeny of the three crosses of the susceptible parent with the resistant and moderately resistant parents P₂, P₃, and P₄ segregated as 3R:13S whereas the progeny in the cross with P₁ showed a segregation ratio of 1R:15S. This suggests that each resistant parent possessed two genes conditioning resistance to tan spot severity caused by P. tritici-repentis race 1. Information on the inheritance of resistance measured as disease severity on adult plants under field conditions is of practical importance for wheat breeding programs seeking improvement in tan spot resistance.     

Carbohydrate degrading enzyme production by plant pathogenic mycelia and microsclerotia isolates of Macrophomina phaseolina through koji fermentation

The ability of hydrolytic enzyme production by two different isolates of Macrophomina phaseolina was studied on apple pomace as a substrate for solid state fermentation (SSF). Initial moisture level, temperature and fermentation period was optimized so as to achieve higher output. Among the two different isolates, microsclerotial (MphP) and mycelial (MphM), MphP was observed as a potential source of different hydrolytic enzymes as compared to MphM. MphP gave higher enzyme activities (IU/gram dry substrate (gds): filter paper cellulase (FPase) activity 196.21 ± 16.3 (120 h), carboxymethyl cellulase (CMCase) 279.34 ± 28.25 (72 h), β-glucosidase (BGL) 129.82 ± 12.41 (96 h), xylanase 2527.88 ± 46.15 (120 h), and amylase 2780.72 ± 38.13 (96 h), respectively at 70% (v/w) IML. The incubation temperature was also found to have impact on the enzyme production ability of Macrophomina strains. The higher enzyme activities were achieved (IU/gds) as follows FPase 276.13 ± 25.02 (40 °C, 120 h), CMCase 278.11 ± 24.47 (35 °C, 144 h), BGL 189.47 ± 15.05 (30 °C, 144 h), xylanase 3845.77 ± 43.38 (35 °C, 144 h) and amylase activity of 3309.45 ± 29.22 (35 °C, 120 h), respectively using MphP at 70% (v/w) IML. This study reports for the first time the potential of carbohydrate degrading enzyme bioproduction by different isolates of M. phaseolina.     

Triterpenoid saponins from corms of Crocus sativus: Localization, extraction and characterization

A mixture of highly glycosilated triterpenoid saponins (CS5) isolated from the corm of Crocus sativus or saffron showed cytotoxic activity against HeLa tumoral cells. The main reverse phase HPLC fraction of this mixture (CS5-1) contains two new oleanane-type saponins, denominated Azafrine 1 (1) and Azafrine 2 (2). The bidesmosidic saponins were respectively characterized as (1) 3-O-β-d-glucopyranosiduronic acid echinocystic acid 28-O-β-D-galactopyranosyl-(1 → 2)-α-l-arabinopyranosyl-(1 → 2)-[β-d-xylopyranosyl-(1 → 4)]-α-d-rhamnopyranosyl-(1 → 2)-[4-O-di-α-L-rhamnopyranosyl-3,16-dihydroxy-10-oxo-hexadecanoyl]-α-D-fucopyranoside and (2) 3-O-β-D-galactopyranosiduronic acid echinocystic acid 28-O-β-D-galactopyranosyl-(1 → 2)-α-L-arabinopyranosyl-(1 → 2)-[β-D-xylopyranosyl-(1 → 4)]-α-L-rhamnopyranosyl-(1 → 2)-[4-O-di-α-L-rhamnopyranosyl-3,16-dihydroxy-10-oxo-hexadecanoyl]-β-D-fucopyranoside. The surfactant properties of saponins, probably involved in the cytotoxic activity of CS5 and their exclusive localization in the external part or the corm, indicate their possible role as phytoprotectans. The similarity of their structural compositions to that of other triterpenoid saponins which are of special use in the pharmaceutical industry suggest a new application for C. sativus crops through the exploitation of corm for saponin extraction.     

In vitro plant regeneration from decapitated embryonic axes of Clitoria ternatea L.—An important medicinal plant

In vitro clonal propagation of Clitoria ternatea has been achieved by employing decapitated embryonic axes (DEAs) explants. The explants induced multiple shoots on cytokinin-containing medium. Several cytokinins [6-benzylaminopurine (BAP), 6-furfuryl aminopurine (KIN) and thidiazuron (TDZ)] were assayed. The best response was achieved with 2 mg l⁻¹ BAP in which 100% of cultures produced 6.0 ± 0.14 shoots per explant. MS + 1 mg l⁻¹ gibberellic acid (GA₃) was the most suitable for shoot elongation. Regenerated shoots were rooted in half-strength Murashige and Skoog (MS) medium with 0.2 mg l⁻¹ indole-3-butyric acid (IBA). Plantlets were successfully acclimatized and established in soil, and they were morphologically indistinguishable from the source plant. The plantlets attained maturity and flowered normally. The efficient regeneration protocol reported here provides an important method of micropropagation of this plant. Furthermore, this protocol may be used for genetic transformation of this valuable medicinal plant for its further improvement.     

Comparative assessment of antioxidant and cholinesterase inhibitory properties of the marigold extracts from Calendula arvensis L. and Calendula officinalis L.

Calendula sp. is an important medicinal and industrial plant with various bioactivities. In this study, we examined enzyme inhibitory effects of the n-hexane, dichloromethane, acetone, ethyl acetate, methanol, and water extracts of the leaf and flowers of Calendula arvensis L. and C. officinalis L. against acetylcholinesterase (AChE) and butyrylcholinesterase (BChE). The extracts were screened for their antioxidant activity using 2,2-diphenyl-1-picrylhydrazyl (DPPH), ferric ion-chelating capacity and ferric-reducing antioxidant power (FRAP) assays at 250, 500, and 1000 μg mL⁻¹. Total phenol and flavonoid quantification of the extracts was achieved using Folin-Ciocalteau and AlCl₃ reagents, respectively. The ethyl acetate extract of C. arvensis flowers was the most active in AChE inhibition assay (31.24 ± 1.29%), while the n-hexane extract of C. officinalis leaves exerted the highest ferric ion-chelating capacity (74.27 ± 2.25%). Thin layer chromatographic analysis indicated presence of flavonoid and triterpene derivatives mainly in the extracts.     

Microscopy techniques and image analysis for evaluation of some chemical and physical properties and morphological features for seeds of the castor oil plant (Ricinus communis)

Ricinus communis seed is a source of protein and oil with a high potential to use as animal's feedstock and biodiesel production. However, the oil yield and the extraction efficiency depend on the process conditions applied, as well as on the physical, chemical and structural properties of the seed, which have not been fully investigated. Hence, the objective of this study was to evaluate some chemical and physical properties of R. communis seed as well as to describe and quantify the macro and microstructure of this raw material by microscopy techniques and image analysis. Chemical analysis confirmed the seeds’ high contents of protein (28.48 ± 0.25%) and fat (51 ± 0.31%). On the other hand, the values of geometric mean diameter (8.95 ± 0.05 mm), bulk density (538 ± 11 kg/m³), and true density (1458 ± 27 kg/m³), among others, were higher than the ones reported about similar oils seeds. Microstructural studies showed that the endosperm cells presented an ovoid shape, as obtained from the aspect ratio results (AR = 1.28 ± 0.17), and a cell density of 570 ± 10 cell/mm², resulting in a porous structure, while the embryo cells had a cell density of 4903 ± 2 cell/mm², and an AR of 2.41 ± 0.48, related to a more compact structure (rectangular form) in this part of the seed. Regarding to lipids bodies (lb), they were only visible in the endosperm cells, showing a circular shape (AR = 1.16 ± 0.1), and a mean cell density of 9.57 ± 2.40 lipid bodies/μm², associated to protein as observed by the mineral presence (K, P, Mg and S) as determined by the energy dispersive X-ray analysis. Microscopy techniques and images analysis were efficient tools for the characterization of macro and microstructure of seeds and the data obtained integrate numerical information that could be useful for thermal and mechanical processing of R. communis seed, as well as for the design process equipment.     

Heritability of,and genotypic correlations between,aflatoxin traits and physiological traits for drought tolerance under end of season drought in peanut (Arachis hypogaea L.)

More rapid progress in breeding peanut for reduced aflatoxin contamination should be achievable with a better understanding of the inheritance of, aflatoxin trait and physiological traits that are associated with reduced contamination. The objectives of this study were to estimate the heritability of aflatoxin traits and genotypic (r_G) and phenotypic (r_P) correlations between drought resistance traits and aflatoxin traits in peanut. One hundred-forty peanut lines in the F_4:6 and F_4:7 generations were generated from four crosses, and tested under well-watered and terminal drought conditions. Field experiments were conducted under the dry seasons 2006/2007 and 2007/2008. Data were recorded for biomass (BIO), pod yield (PY), drought tolerance traits [harvest index (HI), drought tolerance index (DTI) of BIO and PY, specific leaf area (SLA), and SPAD chlorophyll meter reading (SCMR)], and aflatoxin traits [seed infection and aflatoxin contamination]. Heritabilities of A. flavus infection and aflatoxin contamination in this study were low to moderate. The heritabilities for seed infection and aflatoxin contamination ranged from 0.48 to 0.58 and 0.24 to 0.68, respectively. Significant correlations between aflatoxin traits and DTI (PY), DTI (BIO), HI, biomass and pod yield under terminal drought conditions were found (r_P = −0.25** to 0.32**, r_G = −0.57** to 0.53**). Strong correlations between SLA and SCMR with A. flavus infection and aflatoxin contamination were also found. Positive correlations between SLA at 80, 90, and 100 DAP and aflatoxin traits were significant (r_P = 0.13** to 0.46**, r_G = 0.26** to 0.81**). SCMR was negatively correlated with aflatoxin traits (r_P = −0.10** to −0.40**, r_G = −0.11** to −0.66**). These results indicated that physiological-based selection approaches using SLA and SCMR might be effective for improving aflatoxin resistance in peanut.     

Toxicity of quinones against two-spotted spider mite and three species of aphids in laboratory and greenhouse conditions

Toxicities of the eight quinones were evaluated through leaf dip bioassays conducted against Tetranychus urticae, Myzus persicae, Myzocallis walshii, and Illinoia liriodendri. Based on LC₅₀ values, plumbagin (LC₅₀ = 0.001%) was the most active compound against T. urticae and ubiquinone Q₀ (LC₅₀ = 0.005%), plumbagin (LC₅₀ = 0.010%), and dibromothymoquinone (LC₅₀ = 0.012%) were the most active compounds against M. persicae. The most active compounds against M. walshii were juglone (LC₅₀ = 0.011%) and ubiquinone Q₀ (LC₅₀ = 0.019%), whereas dibromothymoquinone (LC₅₀ = 0.030%), plumbagin (LC₅₀ = 0.033%) and ubiquinone Q₀ (LC₅₀ = 0.058%) were the most toxic to I. liriodendri. Ecotrol (positive control) was the least toxic compound (LC₅₀ = 0.39%) against T. urticae and M. persicae (LC₅₀ = 0.447%). Although the majority of the compounds tested were toxic to all four test species in residual bioassays, there was little overlap among the test species in terms of susceptibility to the compounds and interspecific differences were observed. Regarding structure-activity relationships for quinones, the addition of a hydroxyl group resulted in a significant increase in the toxicity of the 1,4-naphthoquinones, and those possessing a methyl group exhibited the highest levels of activity in T. urticae. The bromine atom at the 2- and 5-positions of the benzoquinone ring is crucial to the toxicity of the compounds against I. liriodendri. Toxicity was greatly affected not only by the number of hydroxyl groups, but also by their positions in the ring in the case of M. walshii. Juglone and plumbagin as residual toxins in the laboratory also reduced the population of two-spotted spider mites compared to EcoTrol™ (positive control) and the negative control in the greenhouse experiment. Some quinones tested may have potential as commercial insecticides and miticides, or alternatively, could serve as lead compounds for the development of more potent crop protection agents.     

Improvement of growth and gymnemic acid production by altering the macro elements concentration and nitrogen source supply in cell suspension cultures of Gymnema sylvestre R. Br

Gymnema sylvestre is an important medicinal plant which bears bioactive compound namely gymnemic acids. The present work deals with optimization of cell suspension culture system of G. sylvestre for the production of biomass and gymnemic acid and we investigated effects of macro elements (NH₄NO₃, KNO₃, CaCl₂, MgSO₄ and KH₂PO₄ - 0.0, 0.5, 1.0, 1.5 and 2.0× strength) and nitrogen source [NH₄⁺/NO₃⁻ ratio of: 0.00/18.80, 7.19/18.80, 14.38/18.80, 21.57/18.80, 28.75/18.80, 14.38/0.00, 14.38/9.40, 14.38/18.80, 14.38/28.20 and 14.38/37.60 (mM)] of Murashige and Skoog medium on accumulation of biomass and gymnemic acid content. The highest accumulation of biomass (165.00 g l⁻¹ FW and 15.42 g l⁻¹ DW) was recorded in the medium with 0.5× concentration of NH₄NO₃ and the highest production of gymnemic acid content was recorded in the medium with 2.0× KH₂PO₄ (11.32 mg g⁻¹ DW). The NH₄⁺/NO₃⁻ ratio also influenced cell growth and gymnemic acid production; both parameters were greater when the NO₃⁻ concentration was higher than that of NH₄⁺. Maximum biomass growth (159.72 g l⁻¹ of FW and 14.95 g l⁻¹ of DW) was achieved at an NH₄⁺/NO₃⁻ ratio of 7.19/18.80, and gymnemic acid production was also greatest at the same concentration of NH₄⁺/NO₃⁻ ratio (11.35 mg g⁻¹ DW).     

Hybrid and environment effects on popcorn kernel physiochemical properties and their relationship to microwave popping performance

The objective of this study was to characterize the effect of hybrid and environment on physical and chemical characteristics of popcorn kernels that have shown importance in predicting end-use quality. Three popcorn hybrids grown in three different environments were tested for physiochemical attributes and popping performance. Hybrid had a significant effect on kernel sphericity, time-to-grind, dietary fiber, sugars, and starch. Environment effect alone affected total mineral content. Hybrid and environment main effects influenced test weight, tangential abrasive dehulling device index, thousand-kernel weight, total carbohydrates, and kernel protein content. Oil adherence to the bag averaged 15.8% and was proportional to oil amount added prior to microwave popping. Unpopped kernels averaged 11.4 ± 5.3%. Most unpopped kernels were observed to successfully pop when heated a second time in microwave tests. Expansion volume was 44.7 ± 3.7 and 47.3 ± 6.4 cm³/g, depending on the method of determination. Expansion volume was correlated (p < 0.05) with several kernel physiochemical parameters that were influenced by hybrid effect. Sphericity, thousand-weight, and total fat are physiochemical characteristics that appear to be good predictors (p < 0.05) of expansion volume.     

Pest-damage relationships for Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) on vegetative soybean

The response of vegetative soybean (Glycine max) to Helicoverpa armigera feeding was studied in irrigated field cages over three years in eastern Australia to determine the relationship between larval density and yield loss, and to develop economic injury levels. Rather than using artificial defoliation techniques, plants were infested with either eggs or larvae of H. armigera, and larvae allowed to feed until death or pupation. Larvae were counted and sized regularly and infestation intensity was calculated in Helicoverpa injury equivalent (HIE) units, where 1 HIE was the consumption of one larva from the start of the infestation period to pupation. In the two experiments where yield loss occurred, the upper threshold for zero yield loss was 7.51 ± 0.21 HIEs and 6.43 ± 1.08 HIEs respectively. In the third experiment, infestation intensity was lower and no loss of seed yield was detected up to 7.0 HIEs. The rate of yield loss/HIE beyond the zero yield loss threshold varied between Experiments 1 and 2 (−9.44 ± 0.80 g and −23.17 ± 3.18 g, respectively). H. armigera infestation also affected plant height and various yield components (including pod and seed numbers and seeds/pod) but did not affect seed size in any experiment. Leaf area loss of plants averaged 841 and 1025 cm²/larva in the two experiments compared to 214 and 302 cm²/larva for cohort larvae feeding on detached leaves at the same time, making clear that artificial defoliation techniques are unsuitable for determining H. armigera economic injury levels on vegetative soybean. Analysis of canopy leaf area and pod profiles indicated that leaf and pod loss occurred from the top of the plant downwards. However, there was an increase in pod numbers closer to the ground at higher pest densities as the plant attempted to compensate for damage. Defoliation at the damage threshold was 18.6 and 28.0% in Experiments 1 and 2, indicating that yield loss from H. armigera feeding occurred at much lower levels of defoliation than previously indicated by artificial defoliation studies. Based on these results, the economic injury level for H. armigera on vegetative soybean is approximately 7.3 HIEs/row-metre in 91 cm rows or 8.0 HIEs/m².     

Fatty acid composition and oxidation stability of hemp (Cannabis sativa L.) seed oil extracted by supercritical carbon dioxide

Supercritical carbon dioxide (SC-CO₂) was employed to extract oil from hemp (Cannabis sativa L.) seeds. For ground seeds, the supercritical extraction was carried out at temperatures of 40, 60 and 80 °C and pressures of 300 and 400 bar. Different solvent-ratios were applied. Supercritical CO₂ extractions were compared with a conventional technique, n-hexane in Soxhlet. The extraction yields, fatty acid composition of the oil and oxidation stability were determined. The seed samples used in this work contained 81% PUFAs, of which 59.6% was linoleic acid (ω-6), 3.4% γ-linolenic (ω-3), and 18% α-linolenic (ω-6). The highest oil yield from seeds was 22%, corresponding to 72% recovery, at 300 bar and 40 °C and at 400 bar and 80 °C. The highest oxidation stability corresponding to 2.16 mM Eq Vit E was obtained at 300 bar and 80 °C.     

Enzyme inhibitory and antioxidant activity of Melia azedarach L. naturalized in Anatolia and its phenolic acid and fatty acid composition

In the present study, acetylcholinesterase (AChE), butyrylcholinesterase (BChE), and tyrosinase inhibitory and antioxidant activities of the fruit and leaf extracts of Melia azedarach L. (Meliaceae) of Turkish origin were evaluated. Enzyme inhibitory activity of the extracts was tested in vitro using ELISA microplate reader. Antioxidant activity of the extracts was tested using 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging, ferrous ion-chelation, and ferric-reducing antioxidant power (FRAP) assays. Phenolic composition of the extracts was elucidated by high performance liquid chromatography (HPLC) and fatty acid compositions of the fatty oils of the fruits and leaves were elucidated by gas chromatography-mass spectrometry (GC-MS). The ethyl acetate extract from the leaves showed the highest inhibition against AChE (33.63 ± 1.40%) and BChE (92.89 ± 3.05%). The methanol extract from the leaves exerted the best antioxidant activity in DPPH radical scavenging and FRAP assays, while the ethyl acetate extracts of the fruits and leaves had the most notable effect in metal-chelation assay.     

Highly efficient in vitro regeneration of the industrial oilseed crop Crambe abyssinica

A highly efficient regeneration protocol for oilseed crop Crambe abyssinica has been developed using hypocotyls as explants in this study. Crambe is a potential engineering oilseed crop for industrial purposes as it contains 55-60% erucic acid in its oil and, more importantly, it does not outcross with any food oil seed crops. However, the low regeneration frequency with the currently available protocols is still a limiting factor for genetic modification of Crambe. In this study, we investigated the effects of N-source, C-source, AgNO₃, cultural conditions as well as the concentration and combination of plant growth regulators (PGR) on the regeneration frequency of C. abyssinica. The results showed that all these factors, especially the N-source and PGR concentrations and combinations, played an important role in shoot regeneration. Among all the factors tested, the combination of using hypocotyls from C. abyssinica cv. galactica, the Lepiovre basal medium supplemented with 16 g l⁻¹ glucose, 0.5 g l⁻¹ AgNO₃, 2.2 mg l⁻¹ thidiazuron (TDZ), 0.5 mg l⁻¹ α-naphthaleneacetic acid (NAA), 2.5 g l⁻¹ Gelrite, seeds germinated in dark for 3 days and explants cultured in light, gave the best regeneration frequency (over 95%). The results also suggest that reducing the content of NH₄⁺ or keeping a suitable NO₃⁻/NH₄⁺ ratio in the regeneration medium would be crucial to Crambe shoot regeneration.     

Mosquitocidal activity of two Bacillus bacterial endotoxins combined with plant oils and conventional insecticides

The full whole culture (FWC), containing parasporal protein toxins of Bacillus thuringiensis israelinsis (Bti) and Bacillus sphaericus 2362 (Bs), either singly or in combination with plant oils and commercial insecticides, was tested against larval and adult stages of Culex pipiens mosquitoes under controlled laboratory conditions. In terms of LC₅₀ values recorded after 24, 48, 72 and 96 h, the bacterial toxins showed high potency towards both larvae and adults of mosquitoes in a dose-dependent manner. Generally, the Bti toxin seemed to be more potent than the Bs toxin. For example, the Bti toxin showed a 24 h LC₅₀ of 8.2 ppm against mosquito larvae compared to 13.6 ppm for the Bs toxin. In the adult bioassay, the obtained 24 h LC₅₀ values were 0.064 and 0.085 mg/cm², respectively for the two bacterial toxins. The bacterial toxins mixed with plant oils or insecticides at equitoxic doses (e.g., LC₂₅ values) mostly showed potentiation effects, either against larvae or adults of the tested insect. Among a total of 14 paired mixtures, only the joint action estimated for the mixture of malathion + Bti or Bs was accounted as additively. Combining Bti or Bs endotoxins at LC₀ with different plant oils and insecticides at LC₅₀ concentration levels each, has resulted in considerable synergism against either larvae or adults. In the case of larval bioassays, the maximum synergistic factor (SF) obtained (ca. 2.0) was entitled to the mixture of Bti + spinosad. In the adult bioassays, the mixtures containing Curcuma longa or Melia azedarach oil extracts with Bti or Bs toxins achieved a SF accounted to 2.0. The results of the present study may be considered as an additional contribution to the area of joint toxicity of biocidal agents combining bacterial toxins, plant oils and traditional insecticides. The reached findings may encourage future research to elucidate its performance under practical field conditions.     

Mild peroxyformic acid fractionation of Miscanthus × giganteus bark. Behaviour and structural characterization of lignin

Miscanthus × giganteus bark was subjected to mild fractionation with peroxyformic acid by a two stage process. A factorial experimental design was used to study and quantify the effect of the variables (formic acid concentration (80-90%), hydrogen peroxide concentration (0.2-0.4%), temperature of the first stage (60-80 °C), and treatment time of the second stage (60-120 min)) on the main parameters of fractionation: pulp yield, remaining lignin and total polysaccharides in pulp. The dependence of lignin precipitation rate on hydrogen peroxide concentration in liquor was also studied. Hydrogen peroxide concentrations inferior to 0.5% seems to be suitable to recover high percentages of lignin. The isolated lignin was analysed by 2D-HSQC, ¹³C- and ³¹P NMR spectroscopy, FTIR spectroscopy, size-exclusion chromatography and chemical analysis. The most important chemical modifications taken place in the lignin during the fractionation were identified: β-O-4′ cleavage and hydrolysis of LC-bond structures. The C9-formula was also determined: C₉H_6.81O_2.90(OCH₃)_0.68(COOH)_0.07(OH^Ph)_0.38(OH^Al)_0.33.