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Insect Bioassay

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https://www.readbyqxmd.com/read/28925548/a-bifunctional-catalase-peroxidase-makatg1-contributes-to-virulence-of-metarhizium-acridum-by-overcoming-oxidative-stress-on-the-host-insect-cuticle
#1
Guohong Li, Anni Fan, Guoxiong Peng, Nemat O Keyhani, Jiankang Xin, Yueqing Cao, Yuxian Xia
Microbial pathogens are exposed to damaging reactive oxygen species (ROS) produced from a variety of sources including chemical reactions due to exposure to stress (UV, heat) or by hosts as a defense response. Here we demonstrate that a bifunctional catalase-peroxidase, MakatG1, in the locust-specific fungal pathogen, Metarhizium acridum, functions as a ROS detoxification mechanism during host cuticle penetration. MakatG1 expression was highly induced during on-cuticle appressoria development as compared to vegetative (mycelia) growth or during in vivo growth in the insect hemocoel...
September 19, 2017: Environmental Microbiology
https://www.readbyqxmd.com/read/28920566/field-evolved-resistance-to-%C3%AE-cyhalothrin-in-the-lady-beetle-eriopis-connexa
#2
P M G Costa, J B Torres, V M Rondelli, R Lira
Natural enemies are exposed to insecticide sprays for herbivorous species and may evolve field resistance to insecticides. Natural enemies selected for resistance in the field, however, are welcome for pest control. The susceptibility of 20 populations of Eriopis connexa from various crop ecosystems to λ-cyhalothrin was tested. Three bioassays were conducted: (i) topical treatment with lethal dose (LD)50 previously determined for populations considered standard for susceptibility (LD50S) and for resistance (LD50R) to λ-cyhalothrin at technical grade; (ii) dose-mortality assay to calculate the LD for populations exhibiting significant survival to the LD50R; and (iii) determination of survival when exposed to dried residues at field rates...
September 18, 2017: Bulletin of Entomological Research
https://www.readbyqxmd.com/read/28911226/identification-of-the-ubiquitous-antioxidant-tripeptide-glutathione-as-a-fruit-fly-semiochemical
#3
Xavier Cheseto, Donald L Kachigamba, Sunday Ekesi, Mary Ndung'u, Peter E A Teal Deceased, John J Beck, Baldwyn Torto
Many insects mark their oviposition sites with a host marking pheromone (HMP) to deter other females from over-exploiting these sites. Previous studies have identified and used HMPs to manage certain fruit fly species; however, few are known for African indigenous fruit flies. The HMP of the African fruit fly, Ceratitis cosyra, was identified as the ubiquitous plant and animal antioxidant tripeptide, glutathione (GSH). GSH was isolated from the aqueous extract of adult female fecal matter, and characterized by LC-QTOF-MS...
September 15, 2017: Journal of Agricultural and Food Chemistry
https://www.readbyqxmd.com/read/28893327/new-activity-of-yamamarin-an-insect-pentapeptide-on-immune-system-of-mealworm-tenebrio-molitor
#4
K Walkowiak-Nowicka, G Nowicki, M Kuczer, G Rosiński
In insects, two types of the immune responses, cellular and humoral, constitute a defensive barrier against various parasites and pathogens. In response to pathogens, insects produce a wide range of immune agents that act on pathogens directly, such as cecropins or lysozyme, or indirectly by the stimulation of hemocyte migration or by increasing phenoloxidase (PO) activity. Recently, many new immunologically active substances from insects, such as peptides and polypeptides, have been identified. Nevertheless, in the most cases, their physiological functions are not fully known...
September 12, 2017: Bulletin of Entomological Research
https://www.readbyqxmd.com/read/28888965/-click-reaction-based-synthesis-of-nimbolide-derivatives-and-study-of-their-insect-antifeedant-activity-against-spodoptera-litura-larvae
#5
Bandi Siva, Amujuri Devi, Arramsetti Venkanna, Borra Poornima, Genji Sukumar, Solipeta Divya Reddy, Movva Vijaya, Ramesh Ummanni, Katragadda Suresh Babu
A series of Nimbolide-triazole conjugates were synthesized through copper(I)- catalyzed azide-alkyne "click" chemistry approach and these derivatives (2-4, 2a-2l) were characterized using modern spectroscopic techniques. Antifeedant activities of these derivatives were studied on Tobacco Caterpillar, Spodoptera litura (F.) using no-choice leaf disk bioassay. Interestingly, the synthesized derivatives were more effective in reducing feedancy by insect species when compared to the parent nimbolide. Among the tested compounds, 2a, 2c, and 2d showed potent antifeedancy with ED50 values of 0...
September 6, 2017: Fitoterapia
https://www.readbyqxmd.com/read/28888768/assessment-of-a-cricket-acheta-domesticus-bioassay-for-chequa-iflavirus-and-bunya-like-virus-from-redclaw-crayfish-cherax-quadricarinatus
#6
Kitikarn Sakuna, Jennifer Elliman, Leigh Owens
Chequa iflavirus and a bunya-like virus infect redclaw crayfish (Cherax quadricarinatus) and they may cause mortality reaching 20-40% after about three weeks after a stress event. To complete River's postulates for viruses, virus-free animals are needed. Due to a lack of chequa iflavirus and bunya-like virus-free crayfish (testing shows>85% infection rate) coupled with the facts that iflavirus and bunyaviruses are found in insects and that crickets had been successful alternate hosts for crustacean viruses before, Acheta domesticus was trialled asa bioassay animal...
September 6, 2017: Journal of Invertebrate Pathology
https://www.readbyqxmd.com/read/28871265/expression-of-a-chimeric-gene-encoding-insecticidal-crystal-protein-cry1aabc-of-bacillus-thuringiensis-in-chickpea-cicer-arietinum-l-confers-resistance-to-gram-pod-borer-helicoverpa-armigera-hubner
#7
Alok Das, Subhojit Datta, Shallu Thakur, Alok Shukla, Jamal Ansari, G K Sujayanand, Sushil K Chaturvedi, P A Kumar, N P Singh
Domain swapping and generation of chimeric insecticidal crystal protein is an emerging area of insect pest management. The lepidopteran insect pest, gram pod borer (Helicoverpa armigera H.) wreaks havoc to chickpea crop affecting production. Lepidopteran insects were reported to be controlled by Bt (cryI) genes. We designed a plant codon optimized chimeric Bt gene (cry1Aabc) using three domains from three different cry1A genes (domains I, II, and III from cry1Aa, cry1Ab, and cry1Ac, respectively) and expressed it under the control of a constitutive promoter in chickpea (cv...
2017: Frontiers in Plant Science
https://www.readbyqxmd.com/read/28867769/transgenic-cotton-plants-expressing-the-hahr3-gene-conferred-enhanced-resistance-to-helicoverpa-armigera-and-improved-cotton-yield
#8
Qiang Han, Zhenzhen Wang, Yunxin He, Yehui Xiong, Shun Lv, Shupeng Li, Zhigang Zhang, Dewen Qiu, Hongmei Zeng
RNA interference (RNAi) has been developed as an efficient technology. RNAi insect-resistant transgenic plants expressing double-stranded RNA (dsRNA) that is ingested into insects to silence target genes can affect the viability of these pests or even lead to their death. HaHR3, a molt-regulating transcription factor gene, was previously selected as a target expressed in bacteria and tobacco plants to control Helicoverpa armigera by RNAi technology. In this work, we selected the dsRNA-HaHR3 fragment to silence HaHR3 in cotton bollworm for plant mediated-RNAi research...
August 30, 2017: International Journal of Molecular Sciences
https://www.readbyqxmd.com/read/28866859/toxin-gene-contents-and-activity-of-bacillus-thuringiensis-strains-against-two-sugarcane-borer-species-diatraea-saccharalis-f-and-d-flavipennella-box
#9
L M Silva, M C Silva, S M F A Silva, R C Alves, H A A Siqueira, E J Marques
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...
September 2, 2017: Neotropical Entomology
https://www.readbyqxmd.com/read/28861736/identification-and-fine-mapping-of-a-new-gene-bph31-conferring-resistance-to-brown-planthopper-biotype-4-of-india-to-improve-rice-oryza-sativa-l
#10
G D Prahalada, N Shivakumar, H C Lohithaswa, D K Sidde Gowda, G Ramkumar, Sung-Ryul Kim, C Ramachandra, Shailaja Hittalmani, Trilochan Mohapatra, Kshirod K Jena
BACKGROUND: Rice (Oryza sativa L.) is the staple food for more than 3.5 billion people, mainly in Asia. Brown planthopper (BPH) is one of the most destructive insect pests of rice that limits rice production. Host-plant resistance is one of the most efficient ways to overcome BPH damage to the rice crop. RESULTS: BPH bioassay studies from 2009 to 2015 conducted in India and at the International Rice Research Institute (IRRI), Philippines, revealed that the cultivar CR2711-76 developed at the National Rice Research Institute (NRRI), Cuttack, India, showed stable and broad-spectrum resistance to several BPH populations of the Philippines and BPH biotype 4 of India...
August 31, 2017: Rice
https://www.readbyqxmd.com/read/28827817/novel-male-produced-aggregation-pheromone-of-the-cerambycid-beetle-rosalia-alpina-a-priority-species-of-european-conservation-concern
#11
Alenka Žunič Kosi, Yunfan Zou, Michal Hoskovec, Al Vrezec, Nataša Stritih, Jocelyn G Millar
Several recent studies have demonstrated the great potential for exploiting semiochemicals in ecology and conservation studies. The cerambycid beetle Rosalia alpina represents one of the flagship species of saproxylic insect biodiversity in Europe. In recent years its populations appear to have declined substantially, and its range has shrunk considerably as a result of forest management and urbanization. Here, we collected volatile chemicals released by males and females of R. alpina. Analyses of the resulting extracts revealed the presence of a single male-specific compound, identified as a novel alkylated pyrone structure...
2017: PloS One
https://www.readbyqxmd.com/read/28823100/-1s-3r-cis-chrysanthemyl-tiglate-sex-pheromone-of-the-striped-mealybug-ferrisia-virgata
#12
Jun Tabata, Ryoko T Ichiki
Derivatives of 2,2-dimethyl-3-(2-methylprop-1-enyl)cyclopropanecarboxylic acid (chrysanthemic acid) are classic natural pyrethroids discovered in pyrethrum plants and show insecticidal activity. Chrysanthemic acid, with two asymmetric carbons, has four possible stereoisomers, and most natural pyrethroids have the (1R,3R)-trans configuration. Interestingly, chrysanthemic acid-related structures are also found in insect sex pheromones; carboxylic esters of (1R,3R)-trans-(2,2-dimethyl-3-(2-methylprop-1-enyl)cyclopropyl)methanol (chrysanthemyl alcohol) have been reported from two mealybug species...
August 19, 2017: Journal of Chemical Ecology
https://www.readbyqxmd.com/read/28770337/overexpression-of-biologically-safe-rorippa-indica-defensin-enhances-aphid-tolerance-in-brassica-juncea
#13
Poulami Sarkar, Kuladip Jana, Samir Ranjan Sikdar
Transgenic mustard plants ( Brassica juncea ) expressing non-allergenic and biologically safe RiD peptide show higher tolerance against Lipaphis erysimi. Rorippa indica defensin (RiD) has previously been reported as a novel insecticidal protein derived from a wild crucifer Rorippa indica. RiD was found to have an effective insecticidal property against mustard aphid, Lipaphis erysimi. In the present study, RiD was highly upregulated in R. indica during aphid infestation initiating a defense system mediated by jasmonic acid (JA), but not by salicylic acid (SA)/abscisic acid (ABA)...
August 2, 2017: Planta
https://www.readbyqxmd.com/read/28766724/a-methodology-based-on-insecticide-impregnated-filter-paper-for-monitoring-resistance-to-deltamethrin-in-triatoma-infestans-field-populations
#14
C Remón, P Lobbia, E Zerba, G Mougabure-Cueto
The domiciliary presence of Triatoma infestans (Klug) (Hemiptera: Reduviidae) after control interventions was reported in recent years. Toxicological studies showed high levels of resistance to pyrethroids suggesting resistance as one of the main causes of deficient control. The aim of the present study was to develop a protocol to test resistance to deltamethrin in T. infestans collected from the field by discriminate concentration. To evaluate field insects, the effect of age (early vs. later) and nutritional state (starved vs...
August 2, 2017: Medical and Veterinary Entomology
https://www.readbyqxmd.com/read/28753233/knockout-of-a-p-glycoprotein-gene-increases-susceptibility-to-abamectin-and-emamectin-benzoate-in-spodoptera-exigua
#15
Y-Y Zuo, J-L Huang, J Wang, Y Feng, T-T Han, Y-D Wu, Y-H Yang
P-glycoprotein [P-gp or the ATP-binding cassette transporter B1 (ABCB1)] is an important participant in multidrug resistance of cancer cells, yet the precise function of this arthropod transporter is unknown. The aim of this study was to determine the importance of P-gp for susceptibility to insecticides in the beet armyworm (Spodoptera exigua) using clustered regularly interspaced short palindromic repeats/CRISPR-associated 9 (CRISPR/Cas9) gene-editing technology. We cloned an open reading frame (ORF) encoding the S...
July 28, 2017: Insect Molecular Biology
https://www.readbyqxmd.com/read/28752548/insecticide-resistance-associated-mechanisms-and-fitness-aspects-in-two-brazilian-stegomyia-aegypti-%C3%A2-aedes-aegypti-populations
#16
P F Viana-Medeiros, D F Bellinato, A J Martins, D Valle
In Brazil, insecticide resistance in Stegomyia aegypti (= Aedes aegypti) (Diptera: Culicidae) populations to pyrethroids and to the organophosphate (OP) temephos is disseminated. Currently, insect growth regulators (IGRs) and the OP malathion are employed against larvae and adults, respectively. Bioassays with mosquitoes from two northeast municipalities, Crato and Aracaju, revealed, in both populations, susceptibility to IGRs and malathion (RR95  ≤ 2.0), confirming the effectiveness of these compounds...
July 28, 2017: Medical and Veterinary Entomology
https://www.readbyqxmd.com/read/28725142/rhanterium-epapposum-oliv-essential-oil-chemical-composition-and-antimicrobial-insect-repellent-and-anticholinesterase-activities
#17
Betul Demirci, Hasan Soliman Yusufoglu, Nurhayat Tabanca, Halide Edip Temel, Ulrich R Bernier, Natasha M Agramonte, Saleh Ibrahim Alqasoumi, Adnan Jathlan Al-Rehaily, Kemal Husnu Can Başer, Fatih Demirci
The essential oil (EO) of the aerial parts of Rhanterium epapposum Oliv. (Asteraceae), was obtained by hydrodistillation. The oil was subsequently analyzed by both GC-FID and GC-MS, simultaneously. Forty-five components representing 99.2% of the oil composition were identified. The most abundant compounds were camphene (38.5%), myrcene (17.5%), limonene (10.1%) and α-pinene (8.7%). Referring to the ethnobotanical utilization, an insecticidal assay was performed, where the oil repelled the yellow fever mosquito Aedes aegypti L...
July 2017: Saudi Pharmaceutical Journal: SPJ: the Official Publication of the Saudi Pharmaceutical Society
https://www.readbyqxmd.com/read/28719628/salt-tolerant-and-sensitive-alfalfa-medicago-sativa-cultivars-have-large-variations-in-defense-responses-to-the-lepidopteran-insect-spodoptera-litura-under-normal-and-salt-stress-condition
#18
Yunting Lei, Qing Liu, Christian Hettenhausen, Guoyan Cao, Qing Tan, Weiye Zhao, Honghui Lin, Jianqiang Wu
In nature, plants are often exposed to multiple stress factors at the same time. Yet, little is known about how plants modulate their physiology to counteract simultaneous abiotic and biotic stresses, such as soil salinity and insect herbivory. In this study, insect performance bioassays, phytohormone measurements, quantification of transcripts, and protein determination were employed to study the phenotypic variations of two alfalfa (Medicago sativa) cultivars in response to insect Spodoptera litura feeding under normal and salt stress condition...
2017: PloS One
https://www.readbyqxmd.com/read/28710552/the-african-froghopper-ptyelus-flavescens-suborder-cicadomorpha-contains-two-novel-and-one-known-peptides-of-the-adipokinetic-hormone%C3%A2-akh-family-structure-function-and-comparison-with-aphid-akh-suborder-sternorrhyncha
#19
Gerd Gäde, Petr Šimek, Heather G Marco
The rationale of "green pesticides" in food security is to use information about endogenous hormones of pest insects to make peptide mimetics that will act against the pest insects to alter their behaviour or physiology, while taking care not to harm beneficial insects or other organisms in the food chain. Such "green" insecticides are designed thus, on the basis of neuropeptide ligand-receptor interaction and it is of paramount interest to have finally a mimetic at hand that is harmful only to pest insects...
July 14, 2017: Amino Acids
https://www.readbyqxmd.com/read/28705395/targeted-disruption-of-the-polyketide-synthase-gene-pks15-affects-virulence-against-insects-and-phagocytic-survival-in-the-fungus-beauveria-bassiana
#20
Wachiraporn Toopaang, Suranat Phonghanpot, Juntira Punya, Cheerapha Panyasiri, Kewarin Klamchao, Rudsamee Wasuwan, Chettida Srisuksam, Duangjai Sangsrakru, Chutima Sonthirod, Sithichoke Tangphatsornruang, Morakot Tanticharoen, Alongkorn Amnuaykanjanasin
The reducing clade III polyketide synthase genes, including pks15, are highly conserved among entomopathogenic fungi. To examine the function of pks15, we used targeted disruption to investigate the impact of Beauveria bassiana pks15 on insect pathogenesis. Southern analysis verified that the Δpks15 mutant was disrupted by a single integration of the transformation cassette at the pks15 locus. The Δpks15 mutant had a slight reduction in radial growth, and it produced fewer spores. Our insect bioassays indicated the Δpks15 mutant to be significantly reduced in virulence against beet armyworms compared to wild type (WT), which could be partially accounted for by its markedly decreased ability to survive phagocytosis...
August 2017: Fungal Biology
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