Relationship Between Molecular Structure and Thermo-mechanical Properties of Candelilla Wax and Amides Derived from (<Emphasis Type="Italic">R</Emphasis>)-12-Hydroxystearic Acid as Gelators of Safflower Oil

In this research, we studied the relationship between the molecular structure of (R)-12-hydroxyoctadecanamide, (R)-N-propyl-12-hydroxyoctadecanamide, and (R)-N-octadecyl-12-hydroxyoctadecanamide and the thermo-mechanical properties of their 2% (wt/wt) organogels developed using safflower oil high in oleic acid (HOSFO) as the liquid phase. Candelilla wax (CW), a well-known edible gelling additive whose main component is hentriacontane, also was studied for comparative purposes. The results obtained show that the attractive interactions (i.e., hydrogen bonding and dipolar interactions) between amide groups and between hydroxyl groups present in the amides resulted in organogels with higher melting temperature, heat of melting, and crystallization parameters than those found in the CW organogel. The rheological parameters associated to the strength of the amide or CW-based gels developed in HOSFO (i.e., yield stress and elastic modulus) seem to be associated with the nature of amide groups (i.e., primary or secondary amide) and the increase in the length of the self-assembly molecular unit (i.e., L value determined by X-ray diffraction) and therefore to the extent of London dispersion forces along the hydrocarbon chain. The creep and recovery measurements allowed an evaluation among the internal structures of the different organogels and demonstrated that independent of the hydrogen bonding and dipolar interaction provided by the amide and the hydroxyl groups, the increase in the hydrocarbon chain length results in higher organogel resistance to deformation and higher instant recovery capacity. However, the stabilization of the self-assembly unit through polar groups (i.e., –CONH₂ in HOA) reduces organogel elasticity but provides a higher extended recovery capacity. The results reported in this investigation showed some relationships between gelator structure and the thermo-mechanical properties of low-molecular-mass organic gelator amides. Our long-term objective is to understand the organogelation process to eventually develop trans-free vegetable oil-based food products with novel textures for the consumers.     

Action of porcine-pancreatic amylase on oxidized-reduced amylose of low degree of modification

Amylose was oxidized with 0.1–0.2 mol of periodate per glucose residue (G), and then reduced with sodium borohydride or borotritide to give an oxidized-reduced amylose of low degree of modification. Mild acid hydrolysis gave erythritol, 2-O-α-d-glucosyl-l-erythritol, higher homologs, and other products. Extensive action of porcine-pancreatic amylase on the polymer gave, besides d-glucose and maltose, oligosaccharides containing one or more oxidized-reduced (modified, M), acyclic residues. The enzymic products containing only one oxidized-reduced residue were identified as a modified tetrasaccharide (MG₃) and a modified pentasaccharide (MG₄). Structures of MG₃ and MG₄ were identified by a combination of enzymic and chemical approaches. With glucoamylase, MG₄ was converted into MG plus d-glucose, whereas MG₃ was totally resistant. On mild acidic hydrolysis, MG₃ was converted into 2-O-α-d-glucosyl-d-erythritol plus maltose. These results indicate that MG₃ is G-M-G-G and that MG₄ is G-G-M-G-G. In principle, MG₄ could occupy the five d-glucose residue, substrate-binding site of porcine-pancreatic amylase in such a way that M, the acyclic structure replacing a d-glucose residue, is placed just to the “left” of the catalytic site. The modified structure, being very vulnerable to acidic hydrolysis, might then be expected to be very readily attacked by the amylase, but in fact, it is not.     

A novel chiral separation material: polymerized organogel formed by chiral gelators for the separation of D- and L-phenylalanine

N-Stearine-N'-stearyl-L-phenylalanine, a chiral compound, was synthesized and used as a gelator for the gelation of polymerizable solvents, such as ss-hydroxyethyl methacrylate (HEMA), styrene, etc. The scanning electron microscope (SEM) images of the gelator aggregates show fibril-like helices, typical chiral aggregates with diameters of 100-200 nm. The solvent molecules were immobilized by capillary forces in the three-dimensional network structures of the organogels. The HEMA organogels containing crosslinker polyethylene glycol dimethacrylates (PEG200DMA) were subsequently polymerized by in situ UV irradiation. A porous polymerized organogels were obtained after removal of gelator aggregates through ethanol extraction. The chiral separation of D- and L-phenylalanine was carried out by the adsorption of the polymerized organogels. The adsorption efficiency of L-phenylalanine on the polymerized organogels was found to be dependent on the concentration of the gelator and crosslinker.     

Toxicity of parathion-methyl to cells, akinetes and heterocysts of the cyanobacterium Cylindrospermum, sp. and the probit analysis of toxicity

The toxicity of a commercial formulation of the insecticide parathion‐methyl to the N2‐fixing filamentous cyanobacterium (blue‐green alga) Cylindrospermum, sp. was studied. A concentration of parathion‐methyl of 0.5 ppm caused growth increase in liquid growth media. The minimum inhibitory concentration of parathion‐methyl for both types (N₂, fixing and nitrate supplemented) of liquid and solid media was 1.0 ppm. LC₅₀ values were: 4.4 ppm (liquid, N₂, fixing), 5.5 ppm (liquid, nitrate supplemented), 3.3 ppm (agar, N₂‐fixing) and 4.0 ppm (agar, nitrate supplemented). LC100 values for N₂‐fixing liquid and both types of agar media were 10.0 ppm, while for the liquid nitrate supplemented medium the LC₁₀₀ was 12.0 ppm. Both akinete (spore) formation and germination were inhibited below the highest permissive concentration of 8.0 ppm, with the insecticide incorporated in the agar media. In soil, the LC50 and LC100 values for parathion‐methyl were 13.6 and 30 ppm, respectively. Both the dehydrogenase activity of heterocysts (monitored by 2,3,5‐triphenyl tetrazolium chloride reduction) and the nitrogen concentration of cultures (estimated by the micro‐Kjeldahl method) were affected by the insecticide, but the latter (N₂‐fixation) was more sensitive. The Kruskal‐Wallis H test on the numbers of vegetative cells in the filaments revealed that the insecticide significantly affected the division of vegetative cells. The cyanobacterium could detoxify the growth medium containing high levels (30 and 40 ppm) of the insecticide in short‐term exposures at the expense of cell viability.     

The Effect of Shearing in the Thermo-mechanical Properties of Candelilla Wax and Candelilla Wax�CTripalmitin Organogels

We investigated the shearing effect in the thermo-mechanical properties of candelilla wax (CW) and candelilla wax–tripalmitin (CW-TP) organogels developed using safflower oil as the liquid phase. A shear rate of 600 s⁻¹ was applied during cooling (1 °C/min) of 3% CW and 3% CW-1% TP solutions, until reaching nucleation (i.e., 47 °C) or metastable conditions (i.e., 52 °C) then allowing the development of the organogel under quiescent conditions at 15 °C. The thermal and rheological properties of these organogels were compared with the ones of organogels developed under static conditions. The X-ray results showed that under static conditions the CW crystallized in an orthorhombic ( O _^ ) \left( {{{\hbox{O}}_{ \bot }}} \right) subcell packing with a lateral stacking with a length (L) equivalent to the hydrocarbon chain’s length. During organogelation of the 3% CW-1% TP solution, CW and TP co-crystallized in a O _^ {{\hbox{O}}_{ \bot }} subcell packing with TP in a 2L stacking organization. The application of shearing did not modify the molecular packing of the crystals or the melting properties of the organogels. However, the CW and CW-TP organogels developed with shearing showed the formation of larger crystals (i.e., fiber-like or plate-like) in comparison with the ones developed under static conditions. The presence of 1% TP increased the solid fat content, and thus the CW-TP organogels showed higher elasticity (G′) than CW organogels. The organogels developed with the application of shearing until reaching metastable conditions (i.e., CW 52 °C and CW-TP 52 °C) had the highest G′ and yield stress of all organogels investigated. In the same way, creep and recovery analyses showed that CW 52 °C and CW-TP 52 °C organogels had the highest resistance to deformation, lowest instantaneous recovery, and highest extended recovery of all organogels studied. We concluded that application of shear and the extent of its application as a function of supercooling determine crystal size and the proportion of transient to junction zones throughout the three-dimensional crystal network and, therefore, the organogels' rheological properties.     

Boric acid‐induced immunotoxicity and genotoxicity in model insect Galleria mellonella L. (Lepidoptera: Pyralidae)

Boric acid (BA) is widely used in various industrial process and can be accessed to nontarget organisms. This study aimed to investigate the insecticidal effects of BA and its toxic activities with respect to immunologic and genotoxic effects using Galleria mellonella larvae as a model. BA concentrations (78.125–10,000 ppm) were administrated to the larvae using the feeding method. Concentration‐dependent mortality was observed in all larval groups. Probit analysis revealed LC₃₀, LC₅₀, and LC₇₀ values to be 112.4, 320.1, and 911.4 ppm, respectively. These concentrations were used in all bioassays. Drastic reductions in total hemocyte counts along with changes in differential hemocyte counts were observed following BA treatment. Cell viability assays showed dose‐dependent reductions in viable cells and an increase in the necrotic and apoptotic ratios after BA treatment. However, mitotic indices of larval hemocytes did not change at all BA concentrations. The cytotoxic effect of BA led to a significant reduction in cellular immune responses such as encapsulation, melanization, and nodulation activities of treated larvae. While BA increased micronucleus ratios at the highest concentration, comet parameters indicating DNA damage increased in G. mellonella larval hemocytes at all concentrations. These report that BA suppresses the immune system of G. mellonella and also poses risks of genotoxicity at high concentrations.     

An in vitro study of Ocimum sanctum as a chemotherapeutic agent on oral cancer cell-line

Oral squamous cell carcinoma (OSCC) is the most commom cancer in the world. If remain untreated for several years, it may be fatal. Hence, it is important to prevent and treat OSCC at an early stage. In this study the effect of aqueous and dry leaves extract of Ocimum sanctum was observed on Ca9-22 cell line, which is an OSCC cell line. For this, Ca9-22 cell line was cultured and maintained. After 24 h, the cells were treated with aqueous and dry leaves extract of Ocimum sanctum plant. Viability of the cancerous cells were studied by 3-(4, 5-dimethythiazol-2-yl)-2, 5-diphenyl tetrazolium bromide (MTT) assay and neutral red uptake (NRU) assay. Minimum inhibitory concentrations (MIC), lethal concentration₂₅ (LC₂₅), lethal concentration₅₀ (LC₅₀) and highest permissive concentration (HPC) was calculated by probit computational method. Experimentally, the MIC value was 5 mg/L, whereas the HPC was 30 mg/L of the plant extract in aqueous state. For the dry extract the MIC was 5 mg/L whereas the HPC was 35 mg/L for both MTT and NRU assays. For MTT assay LC values: 7.41 (LC₂₅), 14.79 (LC₅₀) and 26.91 mg/L (LC₇₅) for aqueous extract and 12.58 (LC₂₅), 20.89 (LC₅₀), 29.51 mg/L (LC₇₅) for dry extract. For NRU assay LC values were 10.23 (LC₂₅), 14.79 (LC₅₀) and 20.89 mg/L (LC₇₅) aqueous extract, and 16.59 (LC₂₅), 23.44 (LC₅₀), 30.19 mg/L (LC₇₅) dry extract of the plant. From the above study it was concluded that, Ocimum sanctum have anti-cancerous activity. It can further be used for therapeutic purposes.     

Acute toxicity and sub-lethal effects of a pyrethroid (cypermethrin) on survival,development and fitness of Helicoverpa armigera

The chickpea pod borer, Helicoverpa armigera (Hübner) is one of the most destructive pests of India and most of the countries. In this experiment, sub-lethal effects of cypermethrin were evaluated against sixth instar larvae of this pest that had ingested insecticide-treated chickpea pods. The LC₅₀, LC₃₀ and LC₁₀ values of cypermethrin were 80.38, 26.65 and 5.41?mg a.i.?L^?1, respectively, against sixth instar. The sub-lethal effects on fitness, eggs, larvae, pupae, adult longevity and reproduction were observed in H. armigera population that survived exposure to the sub-lethal doses of LC₅₀, LC₃₀ and LC₁₀ of cypermethrin. Survivorship was reduced to 36?days if H. armigera exposed to the sub-lethal dose of LC_50, whereas it was 42?days in unexposed groups. Larvae treated with LC₅₀ dose exhibit lowest intrinsic rate of increase (r_m) (0.0413 females/female/day) and highest (0.0517) with the unexposed group. Time taken by H. armigera to complete one generation (T_c) was 40.09?days, while this time significantly lowered to 32.85?days when exposed to the sub-lethal dose of LC₃₀. Hatching eggs were greatly reduced in the larvae exposed to cypermethrin at all the sub-lethal doses. About 430 eggs/female/generation were recorded after treatment with 80.38?mg/L as compared with untreated females (1390). Larvae that were exposed to sub-lethal concentrations of cypermethrin exhibited lower pupal weight and prolonged pupal developmental times compared control larvae. The overall fitness performance was better in the unexposed population as compared to the population exposed to sub-lethal doses.     

Acute toxic impacts of three heavy metals (copper,zinc, and cadmium) on <Emphasis Type="Italic">Diaphanosoma brachyurum</Emphasis> (Cladocera: Sididae)

Diaphanosoma brachyurum (Cladocera: Sididae) is a common limnetic species in summer-temperate and tropical water bodies. Few studies have investigated the sensitivity of D. brachyurum to toxic chemicals despite this species often being dominant in natural lakes and ponds. We performed acute toxicity tests of three heavy metals, copper (Cu), zinc (Zn), and cadmium (Cd), to D. brachyurum. For D. brachyurum, the lethal concentration (LC)₅₀ values of Cu (24-h LC₅₀ = 16.4 μg/L, 48-h LC₅₀ = 10.4 μg/L) and Zn (24-h LC₅₀ = 253.4 μg/L, 48-h LC₅₀ = 174.1 μg/L) were lower than those for D. magna, one of the most used test organisms for toxic chemicals. On the other hand, for D. brachyurum the 24-h LC₅₀ of Cd (166.4 μg/L) was much greater than that for D. magna, and the 48-h LC₅₀ of Cd (69.8 μg/L) was comparable. Our results indicate that D. brachyurum may be more strongly influenced by Zn and Cu than is D. magna. It is likely that the summer plankton community in which Diaphanosoma species is dominant is more sensitive to heavy metals than a community in which Daphnia species are dominant.     

Toxic effect of deltamethrin on the life table and development of Helicoverpa armigera (Hubner)

Effect of deltamethrin (Decis 2.8% EC) on the fitness of Helicoverpa armigera (Hübner) was determined using demographic studies. Survivorship (I_x) and expectancy (e_x) was high with commencement of age and gradually decreased with progression of age in the exposed and unexposed groups. Highest number of unhatched eggs (~20%) was recorded with LC₅₀ (79.0 mg/L) opposed to 1% in the control. Daily fecundity rate was significantly greater (200 females/day) in the control than 126 in LC₂₀ (5.13 mg/L). Potential fecundity was lowest (179 females/female/generation) with LC₅₀ treatment than 675 in the control. Smallest value of intrinsic rate of increase (r_m) occurred at LC₅₀ (0.0393 females/female/day) while the highest value (0.0539) was at control. Overall larval development was significantly reduced to 18.0 days with LC₅₀ opposed to 24.1 days at control. Pupal period was shortened to 7.6 days with LC₅₀, while it recorded 9.3 days in control.     

Life expectancy (ex ) and stable age distribution (Cx ) of Plutella xylostella (L.) (Lep.: Yponomeutidae), exposed to sublethal doses of hexaflumuron

The diamondback moth, Plutella xylostella (L.) is a major pest of crucifers in Iran. In this study, the influence of two sublethal concentrations (LC₁₀ and LC₂₅) of an insect growth regulator, hexaflumuron on life expectancy (e _x ), stable age distribution (C _x ), age-specific fertility (m _x ) and number of fertile eggs per day was investigated. Results showed that the sublethal doses of hexaflumuron decreased life expectancy (e _x ), age-specific fertility (m _x ) and number of fertile eggs per day of P. xylostella. Also stable age distribution (C _x ) of population in next generation was changed and rate of adults in sublethals was increased compared to control. According obtained results, hexaflumuron is a good choice for IPM strategy in controlling the diamondback moth.     

Interactions between entomopathogenic nematodes and imidacloprid for rose sawfly control

Rose sawfly, Arge ochropus (Gmelin), is one of the most important pests of ornamental plants such as roses and wild rose bushes in Northern Iran. We investigated the interactions between the insecticides imidacloprid and the entomopathogenic nematodes Heterorhabditis bacteriophora and Steinernema carpocapsae as control agents of fifth-instar larvae in the laboratory. The larvae were very susceptible to S. carpocapsae (LC₅₀: 21 infective juvenile per larva) and H. bacteriophora (LC₅₀: 32). Combinations of two imidacloprid rates (LC₃₀ and LC₅₀) and four rates of each nematode species (LC₂₅–LC₇₅) were tested. Combinations with the lower imidacloprid rate except for that with the highest H. bacteriophora rate caused higher mortality than both respective single-agent treatments. In combination with the higher imidacloprid rate, only one combination with H. bacteriophora and two combinations with S. carpocapsae caused higher mortality than both respective single-agent treatments. Interactions were generally stronger at the lower imidacloprid rate and were stronger for S. carpocapsae (synergistic in seven combinations, additive in one) than for H. bacteriophora (synergistic in two, additive in six). Synergistic imidacloprid-S. carpocapsae combinations could be a useful tool for the control of A. ochropus larvae that would simultaneously control other common pests susceptible to imidacloprid.     

Contact and fumigant toxicities of calamusenone isolated from Acorus gramineus rhizome against adults of Sitophilus zeamais and Rhizopertha dominica

Abstract Calamusenone [3,8‐dimethyl‐5‐(1‐methylethylidene)‐1,2,3,4,5,6,7,8‐octahydroazulene‐6‐one, C₁₅H₂₂O] from Acorus gramineus Soland rhizome was tested in the laboratory for its insecticidal activities against adults of Sitophilus zeamais Motsch. and Rhizopertha dominica (Fab.), using dry film contact and fumigation methods. Responses varied with insect species, dosage and exposure time. In the dry film contact experiment, the highest insecticidal effects of calamusenone against S. zeamais and R. dominica adults were produced at 170.32 μg/cm² after treatment for 72 h, with 96.2% and 98.7% mortalities, respectively. The median lethal concentration (LC₅₀) (72 h) values of calamusenone against S. zeamais and R. dominica adults were 67.00 μg/cm² and 77.30 μg/cm², respectively. As a potential fumigant, calamusenone showed moderate insecticidal effect on the adults of S. zeamais and R. dominica in fumigation experiment, with their LC₅₀ (120 h) values of 125.71 μL/L and 93.64 μL/L respectively. Calamusenone isolated from A. gramineus rhizome showed promise as a novel pesticide candidate for stored‐product pest control.     

Peptides and peptoids—A quantum chemical structure comparison

Peptoids represent a very interesting structure alternative to peptides. Based on ab initio MO theory employing the 6-31G* and 3-21G basis sets and considering correlation energy, a systematic structure comparison between the basic structure units of peptoids and peptides is performed. The calculations show three minimum conformations denoted as C_7β, α_D, and α that do not correspond to conformers on the peptide potential energy hypersurface. The possibility of cis peptide bonds in the peptoids was examined. The solvent influence on the structure was estimated by means of various quantum chemical continuum models. © 1996 John Wiley & Sons, Inc.     

Effect of zinc on four populations and two generations of Gammarus pulex (L.)

1. The amphipod Gammarus pulex (L.) is increasingly used in toxicity assessments and is usually obtained from wild populations. Interpopulation variability in response to toxicants may be due to genetic or phenotypic differences and could be large in wild-caught organisms exposed to different environmental conditions. This paper describes an investigation designed to assess the extent of lethal and sublethal variability between four different G. pulex populations when exposed to zinc, and to determine whether differences observed in the parental generation were also apparent in offspring bred in the laboratory. 2. The mortality of G. pulex from one of the four field-caught populations (Crags Stream) was significantly lower than for animals from the other three populations for the first 2 days of exposure. After 6 days’ exposure the LC₅₀ values for all four populations did not differ significantly, and were approximately 1.0 mg Zn 1-^?1. Sublethal effects on feeding rate after 6 days’ exposure were also similar for all four populations (feeding rate EC₅₀ approximately 0.5 mg Zn 1-^?1). 3. Lethal effects on the F₁ generation were similar among the four populations, in contrast to the short-term differences observed in the parental generation. These results suggest that interpopulation differences in zinc tolerance in G. pulex are short-lived, and phenotypically rather than genetically based.     

Sublethal effects of spirodiclofen on the demographic parameters of Tetranychus urticae Koch (Acari: Tetranychidae)

Abstract

The two-spotted spider mite, Tetranychus urticae Koch is one of the most common pests of agricultural crops. The use of sublethal doses can reduce the need of pesticides and prevent pests’ resistance, which is an important step in integrated pest management and safely controlling this pest. The sublethal effects (LC₅, LC₁₅ and LC₃₅) of spirodiclofen on demographic parameters of T. urticae based on the age-stage, two-sex life table theory were investigated under laboratory conditions [25?±?2?°C, 60?±?5% RH and 16:8 (L:D) h]. The longevity, total life span, oviposition period and total fecundity reduced after exposure to LC₁₅ and LC₃₅. Oviposition period ranged from 5.64 to 10.92?days. The gross reproduction rate (GRR), net reproductive rate (R₀) and the finite rate of increase (λ) of the mites treated with LC₁₅ and LC₃₅ were inferior to the results when treated with LC_5, and control. The values of intrinsic rate of increase (r) was 0.2209?day^?1 in the control and this was reduced to 0.1714?day^?1 in LC₃₅. Based on these results, considering the negative impact of spirodiclofen on the population growth of T. urticae, this acaricide can be helpful to achieve an efficient control for T. urticae in frame of integrated pest management.     

Distribution and Toxic Effects of Cadmium and Lead on Maize Roots

Two-day-old seedlings of maize (Zea mays L.) were incubated on Cd and Pb nitrate solutions at the concentrations that inhibited root growth approximately by 50% after two-day-long incubation (LC₅₀; 10^–4 and 10^–3 M, respectively) or completely terminated growth of the primary root after one-day-long incubation (LC; 5 × 10^–4 and 10^–2 M, respectively). Cd and Pb contents were measured using an anodic inversion voltammetric technique in a flow injection system and a histochemical method. At LC₅₀, Cd and Pb were discerned, by histochemical techniques, in all root apical tissues, whereas in the root hair zone, the heavy metals were primarily accumulated in the apoplast of the rhizodermis and cortex and to a lesser extent, in the vascular tissues and parenchyma cells surrounding the metaxylem vessels. Insignificant accumulation of Cd and Pb in the pericycle probably explains why root branching was tolerant to these agents. At LC, Cd and Pb were found in the apoplast of all root tissues, in accordance with the practically complete inhibition of root growth and branching. Irrespectively of Cd and Pb concentrations in the external solution, the metal contents in the root apex exceeded those in the basal region. Procion dyes were used to assess cell death inflicted by Cd and Pb. At LC, the root cap and meristematic cells perished, together with the rhizodermal cells and the outer cortical cells of the root apex, whereas only the rhizodermal cells in the root apical region died at LC₅₀. The evidence that Cd and Pb cross the endodermal barrier at LC presumes that, at lower metal concentrations, the Casparian strip and plasmalemma of the endodermis regulate the transport of these metals into the central cylinder. The authors conclude that the identical barriers control Cd and Pb transport in root tissues.     

Inductive and synergistic interactions between plant allelochemical flavone and Bt toxin Cry1Ac in Helicoverpa armigera

Genetically engineered crops simultaneously produce defensive allelochemicals and Bacillus thuringiensis (Bt) toxin proteins to kill some of the world's most devastating insect pests. How the two types of toxins, when ingested sequentially or simultaneously, interact at both lethal and sublethal doses in these pests remains underexplored. Here, we examined the toxicological interactions between the Bt toxin Cry1Ac and the flavonoid allelochemical flavone in Helicoverpa armigera. Simultaneous exposure of H. armigera neonates to lethal doses (LC₂₅) of Cry1Ac and flavone caused a mortality significantly higher than that of either toxin alone and their expected additive mortality. Preexposure for 24 h to a sublethal dose (LC₁₀) of Cry1Ac followed by 6-d simultaneous exposure to the same dose of Cry1Ac plus a lethal dose (1.6 mg/g diets, LC₅₀) of flavone resulted in a mortality significantly higher than that of the LC₅₀ dose of flavone alone and the expected additive mortality of the LC₅₀ dose of flavone plus the LC₁₀ dose of Cry1Ac. One-day preexposure to the sublethal dose (LC₁₀) of flavone followed by 6-d simultaneous exposure to the LC₅₀ dose (6 ng/cm²) of Cry1Ac plus the LC₁₀ dose of flavone yielded a mortality significantly higher than that of the LC₅₀ dose of Cry1Ac but similar to the expected additive mortality of the LC₅₀ dose of Cry1Ac plus the LC₁₀ dose of flavone. The results suggest that Cry1Ac induces and synergizes the toxicity of flavone against H. armigera larvae.