Search results for "010602 entomology"
showing 10 items of 250 documents
Temporal variations in symbiotic hindgut protist community of the subterranean termite Reticulitermes lucifugus Rossi in Sicily.
2015
The dynamics of symbiotic protist communities of Reticulitermes lucifugus ‘‘Sicily’’ were investigated to assess the effects of seasonal environmental conditions and the termite’s feeding activity. In worker and soldier castes, the total protist population (total abundance), individual species abundances, and species proportions in their hindguts were examined monthly from December 2012 to February 2014. The main protist species taken into account were Dinenympha fimbriata Kirby, D. gracilis Leidy, Pyrsonympha flagellata Gras., Spirotrichonympha flagellata Grassi u. Fo` a, Holomastigotes elongatum Grassi u. Fo`a, and Trichonympha agilis Leidy, while others were not specifically identified, …
Host-ectoparasite associations; the role of host traits, season and habitat on parasitism interactions of the rodents of northeastern Iran
2021
Abstract Background Rodents play a significant role as reservoirs of zoonotic diseases. Nevertheless, their ectoparasite assemblage and host-ectoparasite associations are poorly known. This study intended to give new insights on the relationships between ectoparasites and rodents in northeastern Iran. Methods Rodents were captured using live traps during the year of 2016–2020 and their ectoparasites were collected. Parasitological indices such as infestation rate, prevalence and mean intensity of infestation were analyzed. Results A total of 284 rodents, belonging to 17 species, were trapped which infested by 178 ectoparasites from five orders Siphonaptera, Phthiraptera, Ixodida, Mesostigma…
Colorado potato beetle chymotrypsin genes are differentially regulated in larval midgut in response to the plant defense inducer hexanoic acid or the…
2019
When Colorado potato beetle larvae ingested potato plants treated with the plant defense inducer compound hexanoic acid, midgut chymotrypsin enzyme activity increased, and the corresponding chymotrypsin genes were differentially expressed, evidence of the larval digestive proteolytic system's plasticity. We previously reported increased susceptibility to Cry3Aa toxin in larvae fed hexanoic acid treated plants. Here we show that the most expressed chymotrypsin gene in larvae fed hexanoic acid treated plants, CTR6, was dramatically downregulated in Cry3Aa intoxicated larvae. lde-miR-965-5p and lde-miR-9a-5p microRNAs, predicted to target CTR6, might be involved in regulating the response to h…
cDNA sequences of two arylphorin subunits of an insect biliprotein: phylogenetic differences and gene duplications during evolution of hexamerins-imp…
2016
Arylphorins represent a conserved class of hexameric ∼500 kDa insect hemolymph glycoproteins, rich in aromatic amino acids, which are produced in large quantities at the larval stage as reserves for metamorphosis and egg development. The recently isolated arylphorin from the moth Cerura vinula is unique in being complexed to a novel farnesylated bilin. Protein sequencing suggested the presence of two different ∼85 kDa subunits. Here, we report the complete coding sequences of two cDNAs encoding two arylphorins subunits with 67% identity and calculated physicochemical characteristics in agreement with the isolated holoprotein. Our phylogenetic analyses of the hexamerins revealed monophyletic…
Isolating, characterising and identifying a Cry1Ac resistance mutation in field populations of Helicoverpa punctigera
2018
AbstractTransgenic cotton expressing insecticidal proteins from Bacillus thuringiensis (Bt) has been grown in Australia for over 20 years and resistance remains the biggest threat. The native moth, Helicoverpa punctigera is a significant pest of cotton. A genotype causing resistance to Cry1Ac in H. punctigera was isolated from the field and a homozygous line established. The phenotype is recessive and homozygous individuals possess 113 fold resistance to Cry1Ac. Individuals that carry Cry1Ac resistance genes are rare in Australia with a frequency of 0.033 being detected in field populations. RNAseq, RT-PCR and DNA sequencing reveals a single nucleotide polymorphism at a splice site in the c…
Gasmin ( BV2-5 ), a polydnaviral-acquired gene in Spodoptera exigua. Trade-off in the defense against bacterial and viral infections
2015
Thousands of Hymenopteran endoparasitoids have developed a unique symbiotic relationship with viruses named polydnavirus (PDVs). These viruses immunocompromise the lepidopteran host allowing the survival of the wasp eggs. In a previous work, we have shown the horizontal transfer of some polydnaviral genes into the genome of the Lepidoptera, Spodoptera exigua. One of these genes, BV2-5 (named gasmin) interferes with actin polymerization, negatively affecting the multiplication of baculovirus in cell culture. In this work, we have focused in the study of the effect of Gasmin expression on different aspects of the baculovirus production. In addition, and since actin polymerization is crucial f…
Effect of substitutions of key residues on the stability and the insecticidal activity of Vip3Af from Bacillus thuringiensis
2021
Modern agriculture demands for more sustainable agrochemicals to reduce the environmental and health impact. The whole process of the discovery and development of new active substances or control agents is sorely slow and expensive. Vegetative insecticidal proteins (Vip3) from Bacillus thuringiensis are specific toxins against caterpillars with a potential capacity to broaden the range of target pests. Site-directed mutagenesis is one of the most approaches used to test hypotheses on the role of different amino acids on the structure and function of proteins. To gain a better understanding of the role of key amino acid residues of Vip3A proteins, we have generated 12 mutants of the Vip3Af1 …
Novel mutations in the voltage-gated sodium channel of pyrethroid-resistant Varroa destructor populations from the Southeastern USA
2016
The parasitic mite Varroa destructor has a significant worldwide impact on bee colony health. In the absence of control measures, parasitized colonies invariably collapse within 3 years. The synthetic pyrethroids tau-fluvalinate and flumethrin have proven very effective at managing this mite within apiaries, but intensive control programs based mainly on one active ingredient have led to many reports of pyrethroid resistance. In Europe, a modification of leucine to valine at position 925 (L925V) of the V. destructor voltage-gated sodium channel was correlated with resistance, the mutation being found at high frequency exclusively in hives with a recent history of pyrethroid treatment. Here,…
Mutations in the voltage-gated sodium channel gene associated with deltamethrin resistance in commercially sourced Phytoseiulus persimilis
2020
The implementation of Integrated Pest Management (IPM) in current agricultural practice is a convenient and very effective strategy to maintain pest populations under control. The use of Biological Control Agents, like Phytoseiulus persimilis, is key for the success of such approach. This predatory mite is widely used since it is very effective for controlling the two spotted spider mite (Tetranychus urticae), one of the most devastating pests worldwide. Here we show the identification of mutations located in the Voltage Gated Sodium Channel (VGSC) of P. persimilis, that correlate with the reduced susceptibility to deltamethrin observed in commercially sourced colonies of this predatory mit…
Characterization of two groups of Spodoptera exigua Hübner (Lepidoptera: Noctuidae) C-type lectins and insights into their role in defense against th…
2018
Insect innate immunity relies on numerous soluble and membrane-bound receptors, named pattern recognition proteins (PRPs), which enable the insect to recognize pathogen-associated molecular patterns. C-type lectins are among the best-studied PRPs and constitute the most diverse family of animal lectins. Here we have characterized two groups of Spodoptera exigua C-type lectins that differ in their phylogeny, domain architecture, and expression pattern. One group includes C-type lectins with similar characteristics to other lepidopteran lectins, and a second group includes bracoviral-related lectins (bracovirus-like lectins, Se-BLLs) recently acquired by horizontal gene transfer. Subsequently…