Toxicity of an Annonin-Based Commercial Bioinsecticide Against Three Primary Pest Species of Stored Products

The effects of a bioinsecticide formulation based on extract of Annona squamosa L. (Annonaceae) containing 10,000 mg L^?1 of acetogenin annonin as the main active ingredient were investigated against three primary pest species of stored grains in Brazil [maize weevil Sitophilus zeamais Motschulsky (Coleoptera: Curculionidae), Mexican bean weevil Zabrotes subfasciatus (Boheman) (Coleoptera: Chrysomelidae: Bruchinae), and cowpea weevil Callosobruchus maculatus (Fabricius) (Coleoptera: Chrysomelidae: Bruchinae)] by means of residual contact bioassays. In a concentration-dependent manner, the annonin-based commercial bioinsecticide caused significant adult mortality of C. maculatus (LC₅₀ = 6890 μL kg^?1), S. zeamais (LC₅₀ = 2781 μL kg^?1), and Z. subfasciatus (LC₅₀ = 2120 μL kg^?1) after 120 h of residual contact exposure. In addition to acute toxicity, the tested bioinsecticide also promoted a significant reduction of the number of eggs laid by females of C. maculatus (EC₅₀ = 5949.7 μL kg^?1) and Z. subfasciatus (EC₅₀ = 552.7 μL kg^?1). Moreover, the bioinsecticide significantly reduced the number of emerged insects (F₁ generation) of C. maculatus (EC₅₀ = 2763.0 μL kg^?1), S. zeamais (EC₅₀ = 1380.8 μL kg^?1), and Z. subfasciatus (EC₅₀ = 561.5 μL kg^?1). The bioinsecticide also reduced the percentage of damaged grains for the three pest species studied, and its grain-protectant properties are comparable to or superior in efficacy in relation to a diatomaceous earth-based insecticide (Insecto® at 1000 mg kg^?1) used as a positive control. Thus, this standardized formulation has promising bioactivity against stored insect species and can be a useful component for IPM of stored grains in Brazil and elsewhere.     

Toxicity of Secondary Metabolites from Meliaceae Against <Emphasis Type="Italic">Spodoptera frugiperda</Emphasis> (J. E. Smith) (Lepidoptera: Noctuidae)

The study was carried out to evaluate the bioactivity of secondary metabolites from Trichilia pallida, Trichilia pallens, and Toona ciliata against fall armyworm Spodoptera frugiperda (J. E. Smith) larvae. The studied compounds included (+/?)-catechins, a triglyceride, and cedrelone isolated from T. ciliata branches, fruits, and stems, respectively; dammaradienol isolated from T. pallida leaves; and scopoletin isolated from T. pallens branches. The compounds’ activity was evaluated through ingestion and topic treatment. Treated artificial diet was offered to first instar larvae to evaluate ingestion effect, while an application on the dorsal thoracic region of third instar larvae was used to evaluate the topic effect. Mortality was assessed daily, and larval weight was recorded after 7 days for ingestion and 5 days for topic application. Scopoletin and triglyceride caused low mortality rates and reduction in larval weight by ingestion, (+/?)-catechins caused larval weight reduction by ingestion, and scopoletin reduced survival by topic treatment. The most effective compound was cedrelone that affected larval survival and development mainly by ingestion. The estimated LC₅₀, LC₉₀, and EC₅₀ for cedrelone were 0.0365, 0.0659, and 0.0095%, respectively. Further, cedrelone-treated corn leaf discs were offered to fourth instar larvae during 16 h in choice and no-choice tests. The deterrence indexes obtained in the choice tests were 23.5 and 36.3% at concentrations of 0.0365 and 0.0659, respectively. Consumption of cedrelone-treated leaf discs at the concentration of 0.0659% was lower compared to the control in the no-choice test. Thus, cedrelone caused lethal and sublethal effects and phagodeterrence on S. frugiperda and should be further studied.     

Bio-insecticide <Emphasis Type="Italic">Bacillus thuringiensis</Emphasis> spores encapsulated with amaranth derivatized starches: studies on the propagation “in vitro”

Bacillus thuringiensis (Bt) is one of the bioinsecticides used worldwide due to its specific toxicity against target pests in their larval stage. Despite this advantage, its use is limited because of their short persistence in field when exposed to ultra violet light and changing environmental conditions. In this work, microencapsulation has been evaluated as a promising method to improve Bt activity. The objective of this study was to develop and characterize native and modified amaranth starch granules and evaluate their potential application as wall materials in the microcapsulation of B thuringiensis serovar kurstaki HD-1 (Bt- HD1), produced by spray drying. Native amaranth starch granules were treated by hydrolyzation, high energy milling (HEM) and were chemically modified by phosphorylation and succinylation. The size of the Bt microcapsules varied from 12.99 to 17.14 μm adequate to protect the spores of Bt from ultraviolet radiation. The aw coefficient of the microcapsules produced by the modified starches after drying was low (0.14–1.88), which prevent microbial growth. Microcapsules prepared with phosphorylated amaranth starch presented the highest bacterial count and active material yield. Different concentrations of the encapsulated Bt formulation in phosphorylated amaranth starch showed a high level of insecticidal activity when tested on M. sexta larvae and has great potential to be developed as a bioinsecticide formulation, also, the level of toxicity is much higher than that found in some of the products commercially available.     

Sublethal effects of abamectin on the biological performance of the predatory mite, <Emphasis Type="Italic">Phytoseius plumifer</Emphasis> (Acari: Phytoseiidae)

Traditionally estimating pesticide effects by measuring only lethal effect may underestimate the total negative effect on beneficial arthropods and sublethal effects should be assessed to estimate the total effect of their applications. In this study, sublethal effect of the acaricide abamectin (Vermectin^® 1.8% EC, Giah, Iran) on the predatory mite Phytoseius plumifer (Canestrini &; Fanzago) (Acari: Phytoseiidae) fed on Tetranychus urticae Koch was assessed in laboratory conditions. The adult predators were exposed to the residues of the acaricide on fig leaves and the LC₅₀ value was determined based on a concentration–response analysis. The results showed that sublethal concentrations (LC₁₀, LC₂₀ and LC₃₀) of abamectin severely affected the fecundity and longevity of the treated females of P. plumifer. Furthermore, reproductive and life table parameters of the subsequent generation were affected. The results indicated that adverse effects of abamectin on population growth of P. plumifer were significant, so the results from this study can be used to develop approximate guidelines for the use of abamectin in order to minimize their impact on P. plumifer and related natural enemies.     

Discovery of a Highly Virulent Strain of <Emphasis Type="Italic">Photorhabdus luminescens</Emphasis> ssp<Emphasis Type="Italic">. akhurstii</Emphasis> from Meghalaya,India

Photorhabdus is an insect-pathogenic Gram negative enterobacterium found in the gut of Heterorhabditis nematodes. Photorhabdus is highly virulent to insects, and can kill insects rapidly upon injection at very low concentrations of one to few cells. We characterized the virulence of Photorhabdus symbionts isolated from the Heterorhabditis nematodes collected from various parts of India by injecting different concentrations of bacterial cells into fourth instar larval stage of insect Galleria mellonella. Photorhabdus luminescens ssp. akhurstii strain IARI-SGMG3 from Meghalaya was identified as the most virulent of all the tested strains on the basis of LT₅₀ and LC₅₀ values. This study forms a basis for further investigations on the genetic basis of virulence in Photorhabdus bacteria.     

Preparation and Optimization of Fast-Disintegrating Tablet Containing Naratriptan Hydrochloride Using D-Optimal Mixture Design

Optimization of a lyophilized fast-disintegrating tablet (LFDT) formulation containing naratriptan hydrochloride, an antimigraine drug, was the foremost objective of the study, aiming in achieving fast headache pain relief. The Design-Expert® v10 software was used to generate formulations using D-optimal mixture design with four components: gelatin (X₁), hydrolyzed gelatin (X₂), glycine (X₃), and mannitol (X₄) of total solid material (TSM) w/w. The effect of the relative proportion of each component was determined on friability (Y₁), hardness (Y₂), and in vitro disintegration time (Y₃), which was then applied for formulation optimization. In addition, their effect on tablet porosity was determined via scanning electron microscopy (SEM). Drug-excipient interaction was evaluated using differential scanning calorimetry (DSC). A comparative dissolution study against the conventional tablets was studied. Accelerated stability study was carried out in (Al/Al) and (Al/PVC) blister packs. An in vivo pharmacokinetic study was carried out to compare the optimized formulation and the conventional tablets. The optimized formulation’s responses were 0.30%, 3.4 kg, and 6.12 s for Y₁, Y₂, and Y₃, respectively. No drug-excipient interaction was specified via DSC. The optimized formulation exhibited porous structure as determined via SEM. Dissolution study demonstrated complete dissolution within 1.5 min. Study indicated stability for 78 months in (Al/Al) blister packs. In vivo pharmacokinetic study demonstrated that C_max, AUC_last, and AUC_inf were significantly higher for the developed formulation. As well, the T_max was 1 h earlier than that of convenient tablet. An LFDT would achieve a faster onset of action for naratriptan compared to other formulations.     

Characterization of new <Emphasis Type="Italic">Bacillus thuringiensis</Emphasis> strains from Iran,based on cytocidal and insecticidal activity,proteomic analysis and gene content

Characterization of new Bacillus thuringiensis strains is a valuable tool to discover novel insecticidal toxins and to manage resistance problems. In this study, seven Iranian Bt strains were selected according to their toxicity against Plodia interpunctella, to be thoroughly characterized based on their toxicity, protein profiling, proteomic analysis, gene content and β-exotoxin production. The toxicity was assessed by insect bioassays and cell viability assays (a less cost, time and material consuming technique), using four lepidopteran pests and four lepidopteran cell lines from Trichoplusia ni (Hi5), Helicoverpa zea (HzGUT), Spodoptera exigua (UCR-SE) and Spodoptera frugiperda (Sf21). The selected Bt strains showed similar protein electrophoretic profiles, but differed in toxicity. LC–MS/MS analysis of solubilized crystal proteins and gene content analyses (PCR screening) were compared and correlated with the toxicity results. Based on our data, three Bt strains could be considered as candidates for development of future bioinsecticides.     

Insecticidal activities of monoterpenes and phenylpropenes against <Emphasis Type="Italic">Sitophilus oryzae</Emphasis> and their inhibitory effects on acetylcholinesterase and adenosine triphosphatases

In the present study, six monoterpenes [(?)-citronellal, p-cymene, (?)-menthone, α-pinene, α-terpinene, and (?)-terpinen-4-ol] and two phenylpropenes [trans-cinnamaldehyde and eugenol] were evaluated for their contact and fumigant toxicities against Sitophilus oryzae adults. The effects of these compounds on the mortality of S. oryzae adults in stored wheat and their inhibitory effects on acetylcholinesterase (AChE) and adenosine triphosphatases (ATPases) were examined. The tested compounds showed varying degrees of contact toxicity, with trans-cinnamaldehyde (LC₅₀ = 0.01 mg/cm²) being the most potent compound, followed by (?)-menthone (LC₅₀ = 0.013 mg/cm²) and eugenol (LC₅₀ = 0.015 mg/cm²). In a fumigant toxicity assay, the monoterpenes α-terpinene, p-cymene, and (?)-menthone showed the highest toxicities (LC₅₀ = 50.79, 52.37, and 54.08 μl/L air, respectively). Trans-cinnamaldehyde, (?)-citronellal, and eugenol were the least toxic (LC₅₀ > 100 μl/L air). In general, the oxygenated compounds exhibited high contact toxicities while the hydrocarbon compounds exhibited high fumigant toxicities. When tested for their insecticidal activities against S. oryzae in stored wheat, trans-cinnamaldehyde was found to be the most potent compound, with 73.9% mortality at an application rate of 0.5 g/kg and complete mortality (100%) at 1 and 5 g/kg after 1 week of treatment. All of the tested compounds showed AChE inhibition, although (?)-citronellal and trans-cinnamaldehyde presented the strongest enzyme inhibition, with IC₅₀ values of 18.40 and 18.93 mM, respectively. On the other hand, (?)-terpinene-4-ol exhibited the highest inhibition of ATPases, followed by α-pinene and α-terpinene.     

The Plant Alkaloid Camptothecin as a Novel Antifouling Compound for Marine Paints: Laboratory Bioassays and Field Trials

The extensive use of copper and booster biocides in antifouling (AF) paints has raised environmental concerns and the need to develop new AF agents. In the present study, 18 alkaloids derived from terrestrial plants were initially evaluated for AF activity using laboratory bioassays with the bryozoan Bugula neritina and the barnacle Balanus albicostatus. The results showed that 4 of the 18 alkaloids were effective in inhibiting larval settlement of B. neritina, with an EC₅₀ range of 6.18 to 43.11 μM, and 15 of the 18 alkaloids inhibited larval settlement of B. albicostatus, with EC₅₀ values ranging from 1.18 to 67.58 μM. Field trials that incorporated five alkaloids respectively into paints with 20% w/w indicated an in situ AF efficiency of evodiamine, strychnine, camptothecin (CPT), and cepharanthine, with the most potent compound being CPT, which also exhibited stronger AF efficiency than the commercial antifoulants cuprous oxide and zinc pyrithione in the field over a period of 12 months. Further field trials with different CPT concentrations (0.1 to 20% w/w) in the paints suggested a concentration-dependent AF performance in the natural environment, and the effective concentrations to significantly inhibit settlement of biofoulers in the field were ≥?0.5% w/w (the efficiency of 0.5% w/w lasted for 2 months). Moreover, CPT toxicity against the crustacean Artemia salina, the planktonic microalgae Phaeodactylum tricornutum and Isochrysis galbana, was examined. The results showed that 24 h LC₅₀ of CPT against A. salina was 20.75 μM, and 96 h EC₅₀ (growth inhibition) values of CPT to P. tricornutum and I. galbana were 55.81 and 6.29 μM, respectively, indicating that CPT was comparatively less toxic than several commercial antifoulants previously reported. Our results suggest the novel potential application of CPT as an antifoulant.     

A new biopesticide from a local <Emphasis Type="Italic">Bacillus thuringiensis</Emphasis> var. <Emphasis Type="Italic">tenebrionis</Emphasis> (Xd3) against alder leaf beetle (Coleoptera: Chrysomelidae)

Use of chemical pesticides in agriculture harms humans, non-target organisms and environments, and causes increase resistance against chemicals. In order to develop an effective bio-pesticide against coleopterans, particularly against Agelastica alni (Coleoptera: Chrysomelidae) which is one of the serious pests of alder leaf and hazelnut, we tested the insecticidal effect of 21 Bacillus isolates against the larvae and adults of the pest. Bacillus thuringiensis var. tenebrionis-Xd3 (Btt-Xd3) showed the highest insecticidal effect based on screening tests. For toxin protein production and high sporulation of Xd3, the most suitable medium, pH and temperature conditions were determined as nutrient broth medium enriched with salts, pH 7 and 30?°C, respectively. Sporulated Btt-Xd3 in nutrient broth medium enriched with salts transferred to fermentation medium containing soybean flour, glucose and salts. After fermentation, the mixture was dried in a spray dryer, and spore count of the powder product was determined as 1.6?×?10¹⁰ c.f.u. g^?1. Moisture content, suspensibility and wettability of the formulation were determined as 8.3, 86% and 21 s, respectively. Lethal concentrations (LC₅₀) of formulated Btt-Xd3 were determined as 0.15?×?10⁵ c.f.u. ml^?1 for larvae at laboratory conditions. LC₅₀ values were also determined as 0.45?×?10⁶ c.f.u. ml^?1 at the field condition on larval stage. Our results showed that a new bio-pesticide developed from B. thuringiensis tenebrionis (Xd3) (Btt-Xd3) may be valuable as a biological control agent for coleopteran pests.     

Hypocrealean fungi associated with populations of <Emphasis Type="Italic">Ips typographus</Emphasis> in West Carpathians and selection of local <Emphasis Type="Italic">Beauveria</Emphasis> strains for effective bark beetle control

In Slovakia, a diversity of entomopathogenic fungi (Ascomycota, Hypocreales) associated with outbreaks of Ips typographus was studied in 81 localities and as many as 113 in vitro cultures of five entomopathogenic species were isolated from infected individuals: Beauveria bassiana (87 isolates), B. pseudobassiana (14 isolates), B. caledonica (6 isolates), Lecanicillium lecanii (4 isolates) and Isaria farinosa (2 isolates). B. pseudobassiana is recorded in natural populations of I. typographus for the first time. Biological properties of selected Beauveria isolates, including colony growth, biomass production, conidia yield and pathogenicity to I. typographus adults, were studied in a series of laboratory bioassays and much intra- and interspecific variability was detected. B. bassiana isolates produced biomass or conidia at significantly higher rate than B. pseudobassiana and B. caledonica isolates. Two B. bassiana isolates were selected as the most virulent to bark beetle adults, demonstrating a mean LC₅₀ ranging from 0.72 to 2.05?×?10⁶ conidia ml^?1, and were qualified as promising candidates for biocontrol of I. typographus. Their virulence was significantly higher than that of the mycoinsecticides Boverol®, which was used as a reference strain in the virulence bioassays.     

Toxin Gene Contents and Activity of <Emphasis Type="Italic">Bacillus thuringiensis</Emphasis> Strains Against Two Sugarcane Borer Species, <Emphasis Type="Italic">Diatraea saccharalis</Emphasis> (F.) and <Emphasis Type="Italic">D. flavipennella</Emphasis> (Box)

Bacillus thuringiensis (Berliner) bears essential characteristics in the control of insect pests, such as its unique mode of action, which confers specificity and selectivity. This study assessed cry gene contents from Bt strains and their entomotoxicity against Diatraea saccharalis (F.) and Diatraea flavipennella (Box) (Lepidoptera: Crambidae). Bioassays with Bt strains were performed against neonates to evaluate their lethal and sublethal activities and were further analyzed by PCR, using primers to identify toxin genes. For D. saccharalis and D. flavipennella, 16 and 18 strains showed over 30% larval mortality in the 7th day, respectively. The LC₅₀ values of strains for D. saccharalis varied from 0.08 × 10⁵ (LIIT-0105) to 4104 × 10⁵ (LIIT-2707) spores + crystals mL^?1. For D. flavipennella, the LC₅₀ values of strains varied from 0.40 × 10⁵ (LIIT-2707) to 542 × 10⁵ (LIIT-2109) spores + crystals mL^?1. For the LIIT-0105 strain, which was the most toxic to D. saccharalis, the genes cry1Aa, cry1Ab, cry1Ac, cry1B, cry1C, cry1D, cry1F, cry1I, cry2Aa, cry2Ab, cry8, and cry9C were detected, whereas for the strain LIIT-2707, which was the most toxic to D. flavipennella, detected genes were cry1Aa, cry1Ab, cry1Ac, cry1B, cry1D, cry1F, cry1I, cry2Aa, cry2Ab, and cry9. The toxicity data and toxin gene content in these strains of Bt suggest a great variability of activity with potential to be used in the development of novel biopesticides or as source of resistance genes that can be expressed in plants to control pests.     

A Genetic Study of a <Emphasis Type="Italic">Salix</Emphasis> Germplasm Resource Reveals New Insights into Relationships Among Subgenera,Sections and Species

Genetic relationships among 154 genotypes, including 50 species, held within the UK National Willow Collection were analysed using nine primer combinations in an optimised fluorescent amplified fragment length polymorphism (AFLP®) protocol. The AFLP® data resolved relationships at all levels, from discriminating between closely related accessions to differentiating among majority of species, sections and subgenera. The neighbour-joining dendrogram split accessions into three major well-supported clusters, two of which comprised species of the subgenera Vetrix and Salix. Surprisingly, the third (98% bootstrap support) comprised only Salix triandra accessions. The genetic similarity (GS) between S. triandra and Salix or Vetrix was similar (0.39 and 0.40, respectively) and greater than the genetic similarity between Salix and Vetrix (GS?=?0.57). Separate clustering of S. triandra is also supported by hierarchical analysis of molecular variance (AMOVA), that partitioned 31.4% of the total variance between these three groups, whereas only 16.3% was partitioned between the two subgenera. These results challenge all current classifications which assign S. triandra to subgenus Salix. Principal coordinate analysis gave corresponding results and facilitated interpretation of relationships among species within sections of the two subgenera, which are discussed. The study included 40 species which have been used in breeding, and the findings will facilitate the choice of parents and interpretation of the results of different crosses, on the basis of more accurate knowledge of genetic relationships. AFLPs® also detected identical genotypes (within the limits of AFLP® error) which should not be used as distinct parents in breeding programmes.     

Characterization and virulence of <Emphasis Type="Italic">Lecanicillium lecanii</Emphasis> against different aphid species

Seven isolates of Lecanicillium lecanii (Zimmermann) Zare &; Gams isolated in Spain from infected aphids were characterized using sequences of the Internal Transcribed Spacer (ITS) regions and also based on morphological and physiological characteristics. Four of these seven L. lecanii isolates were selected to assess their virulence against nymphs of Myzus persicae (Sulzer), Nasonovia ribisnigri (Mosley), Macrosiphum euphorbiae (Thomas) and Aphis gossypii Glover. Mortality (%), lethal concentration 50 (LC₅₀) and lethal time 50 (TC₅₀) were calculated. The analysis of the sequences of ITS region confirmed that the new isolates were clearly Lecanicillium lecanii. The set of isolates had similar radial growth (51.5–54.0 mm), except for ICAL1 (39 mm). The germination time 50 (GT₅₀) varied between 10.7 h (ICAL3) and 13 h (ICAL5). The isolate ICAL6 showed the highest value for conidial production (3.4 × 10⁸ con ml^?1) and also produced the highest mortality for M. persicae (95%) and was more virulent than the commercial product Vertalec^® (91.6%).     

Selection and Characterization of <Emphasis Type="Italic">Bacillus thuringiensis</Emphasis> (Berliner) (Eubacteriales: Bacillaceae) Strains for <Emphasis Type="Italic">Ecdytolopha aurantiana</Emphasis> (Lima) (Lepidoptera: Tortricidae) Control

The citrus fruit borer, Ecdytolopha aurantiana (Lima, 1927) (Lepidoptera: Tortricidae), is responsible for major losses to the citrus industry because it causes rot and drop of fruits. The current study aimed to select and characterize Bacillus thuringiensis (Berliner, 1911) strains toxic to E. aurantiana. For this purpose, 47 B. thuringiensis strains were evaluated in selective bioassays using first instar larvae of E. aurantiana. The lethal concentration (LC₅₀) of the most toxic strains was estimated, and the strains were characterized by morphological, biochemical, and molecular methods. Of the 47 strains tested, 10 caused mortality above 85% and showed mean lethal concentrations between 1.05E+7 and 1.54E+8 spores mL^?1. The lowest LC₅₀ values were obtained for the HD-1 standard strain and the BR145, BR83, BR52, and BR09 strains. The protein profile showed the presence of Cry proteins of 60, 65, 70, 80, and 130 kDa. The molecular characterization showed the presence of cry1, cry2, cry3, and cry11 genes. The morphological analysis identified three different crystalline inclusions: bipyramidal, round, and cuboidal. The cry1 and cry2 genes were the most frequent among the B. thuringiensis strains evaluated and encode Cry proteins toxic to insects of the order Lepidoptera, which agree with the toxicity results obtained by the selective bioassays against E. aurantiana. The results showed four different B. thuringiensis strains toxic to E. aurantiana at the same level as the HD-1 standard strain, and these strains have biotechnological potential for E. aurantiana control through the production of transgenic plants or the formulation of biopesticides.     

Effects of imidacloprid on the orientation behavior and parasitizing capacity of <Emphasis Type="Italic">Anagrus nilaparvatae</Emphasis>, an egg parasitoid of <Emphasis Type="Italic">Nilaparvata lugens</Emphasis>

Anagrus nilaparvatae (Pang et Wang) (Hymenoptera: Mymaridae), is an egg parasitoid of rice planthoppers, Nilaparvata lugens (Stål) (Homoptera: Delphacidae). This study evaluated effects of the insecticide imidacloprid on orientation behavior and parasitizing capacity of A. nilaparvatae. Sub-lethal concentrations of imidacloprid (LC₂₀ and LC₁₀) disrupted the foraging ability of A. nilaparvatae exposed to imidacloprid through contact or oral routes. Some survivors did not respond to volatiles from N. lugens-infested plants. Responsive individuals were equally attracted to volatiles from N. lugens-infested and healthy plants. Volatiles emitted from rice plants treated with a low concentration of imidacloprid were more attractive to A. nilaparvatae than those from plants treated with a high concentration of imidacloprid. Parasitism of N. lugens by A. nilaparvatae that survived contact with sub-lethal concentrations of imidacloprid did not decrease significantly. When A. nilaparvatae were fed imidacloprid-honey mixture, parasitism rates were 1.49% and 0%, respectively, significantly lower than those of the control (9.58%). Parasitism of N. lugens eggs in high concentration of imidacloprid treated rice plants by A. nilaparvatae decreased significantly. These effects involving disturbed foraging ability and reduced parasitizing capacity of A. nilaparvatae indicated that imidacloprid could decrease the performance of this parasitoid.     

Gas exchanges of an endangered species <Emphasis Type="Italic">Syringa pinnatifolia</Emphasis> and a widespread congener <Emphasis Type="Italic">S. oblata</Emphasis>

Net photosynthetic rate (P_N), transpiration rate (E), water use efficiency (WUE), stomatal conductance (g_s), and stomatal limitation (L_s) were investigated in two Syringa species. The saturation irradiance (SI) was 400 µmol m^-2s^-1 for S. pinnatifolia and 1 700 µmol m^-2s^-1 for S. oblata. Compared with S. oblata, S. pinnatifolia had extremely low g _s . Unlike S. oblata, the maximal photosynthetic rate (P_max) in S. pinnatifoliaoccurred around 08:00 and then fell down, indicating this species was sensitive to higher temperature and high photosynthetic photon flux density. However, such phenomenon was interrupted by the leaf development rhythms before summer. A relatively lower P_N together with a lower leaf area and shoot growth showed the capacity for carbon assimilation was poorer in S. pinnatifolia.     

Determination of the Genetic and Synergistic Suppression of a Methoxyfenozide-Resistant Strain of the House Fly <Emphasis Type="Italic">Musca domestica</Emphasis> L. (Diptera: Muscidae)

Musca domestica Linnaeus (house fly, Diptera: Muscidae) is a major veterinary and medical important pest all over the world. These flies have ability to develop resistance to insecticides. The present trial was performed to discover the inheritance mode (autosomal, dominance, number of genes involved) and preliminary mechanism of methoxyfenozide resistance in order to provide basic information necessary to develop resistance management strategy for this pest. A strain of M. domestica (MXY-SEL) was exposed to methoxyfenozide for 44 generations which developed a 5253.90-fold level of resistance to methoxyfenozide. The overlapping fiducial limits of LC₅₀ values of the reciprocal crosses, F₁ (MXY-SEL ♂?×?Susceptible ♀) and F₁^? (MXY-SEL ♀?×?Susceptible ♂), suggest that inheritance of methoxyfenozide resistance was an autosomal and likely completely dominant trait (D_LC?=?0.93 and 0.94 for F₁ and F₁^?, respectively). Backcrosses of the F₁ with the parental MXY-SEL or Susceptible population predict a polygenic mode of inheritance. Piperonyl butoxide significantly altered the LC₅₀ values, suggesting enhanced detoxification by cytochrome P450-dependent monooxygenases is a major mechanism of resistance to methoxyfenozide in the MXY-SEL strain. The estimated realized heritability was 0.07 for methoxyfenozide. These results would be helpful for the better management of M. domestica.     

Pelagic larval dispersal habits influence the population genetic structure of clam <Emphasis Type="Italic">Gomphina aequilatera</Emphasis> in China

Pelagic larval dispersal habits influence the population genetic structure of marine mollusk organisms via gene flow. The genetic information of the clam Gomphina aequilatera (short larval stage, 10 days) which is ecologically and economically important in the China coast is unknown. To determine the influence of planktonic larval duration on the genetic structure of G. aequilatera. Mitochondrial markers, cytochrome oxidase subunit i (COI) and 12S ribosomal RNA (12S rRNA), were used to investigate the population structure of wild G. aequilatera specimens from four China Sea coastal locations (Zhoushan, Nanji Island, Zhangpu and Beihai). Partial COI (685 bp) and 12S rRNA (350 bp) sequences were determined. High level and significant F_ST values were obtained among the different localities, based on either COI (F_ST?=?0.100–0.444, P?<?0.05) or 12S rRNA (F_ST?=?0.193–0.742, P?<?0.05), indicating a high degree of genetic differentiation among the populations. The pairwise N_m between Beihai and Zhoushan for COI was 0.626 and the other four pairwise N_m values were >?1, indicating extensive gene flow among them. The 12S rRNA showed the same pattern. AMOVA test results for COI and 12S rRNA indicated major genetic variation within the populations: 77.96% within and 22.04% among the populations for COI, 55.73% within and 44.27% among the populations for 12S rRNA. A median-joining network suggested obvious genetic differentiation between the Zhoushan and Beihai populations. This study revealed the extant population genetic structure of G. aequilatera and showed a strong population structure in a species with a short planktonic larval stage.     

Broad-specificity amino acid racemase,a novel non-antibiotic selectable marker for transgenic plants

The broad-specificity amino acid racemase (Bsar) from Pseudomonas putida catalyzes the racemization of various amino acids, offering a flexible and feasible platform to develop a new non-antibiotic selectable marker system for plant transformation. In the present study, we demonstrated that a Bsar variant, Bsar-R174K, that is useful as a selectable marker gene in Arabidopsis and rice that were susceptible to l-lysine and D-alanine. The introduction of wild-type Bsar, Bsar-R174K or Bsar-R174A into E. coli lysine or asparagine auxotrophs was able to rescue the growth of these microorganisms in minimal media supplemented with selectable amino acid enantiomers. The transformation of Arabidopsis with Bsar or Bsar variants based on d-alanine selection revealed that Bsar-R174K had the greatest efficiency (2.40%), superior to kanamycin selection-based transformation (1.10%). Whereas, l-lysine-based selection exhibited lower efficiency for Bsar-R174K (0.17%). The progenies of selected Bsar-R174K transgenic Arabidopsis revealed normal growth properties. In addition, Bsar-R174K transgenic rice was obtained on l-lysine medium with an efficiency of 0.9%, and the progenies of the transgenic rice revealed morphologically normal phenotypes comparable with their wild-type counterparts. This study presents the first report of broad range amino acid racemase Bsar-R174K as a non-antibiotic selectable marker system applied in transgenic plants.