Tribolium

Salt marsh plants were tested for their insecticidal activities against larvae of the confused flour beetle Tribolium confusum (Tenebrionidae). 16 aerial part extracts were obtained using organic solvents of increasing polarity and tested for their anti-feedant and toxicity effects. Responses varied with plant material and extract type. Ethyl acetate extracts of F. laevis, S. echioides and. T. boveana and petroleum ether extract of F. laevis presented, anti-feedant property. However, S. fructicosa seemed to be attractive to the tested flour beetle. Mortalities of 97, 87, 97 and 80% were observed by using respectively ethyl acetate extracts of F. laevis, S. echioides and T. boveana and petroleum ether extract of F. laevis, when applied at a dose of 1%, mixed with the insect diet. This preliminary study showed that F. laevis, S. echioides and T. boveana presented potential bio-insecticidal activity with ethyl acetate extracts, similar result was found with petroleum ether extract of F...

Allelochemical effects were observed when Tribolium castaneum (Herbst) adults were treated with Baccharis salicifolia (Ruiz & Pavon) Pers essential oil. The main biological activities were toxicity and repellence. Terpenes present in the essential oil were identified by GC-MS, and some authentic samples were tested to assess their activity individually. The most acutely toxic compounds after 3 days were β-pinene and pulegone. Most of the monoterpenes elicited symptoms indicative of neurotoxicity. The most repellent compound was α-terpineol. Toxic and repellent effects of chemical derivatives of the major sesquiterpene present in B salicifolia essential oil, as well as a series of monoterpenes, were evaluated in order to investigate structure-activity relationships. The reduced derivatives of the monoterpenes and sesquiterpenes were more repellent that their carbonyl analogues. In addition, unsaturation in the germacrane skeleton enhanced repellent activity. Copyright © 2005 Society of Chemical Industry

A new analytical method using gas chromatography with mass spectrometry (GC–MS) for the quantitative determination of lufenuron, a benzoylphenylurea (BPU) class of insecticide, from wheat flour has been developed and applied for time-dependant residue monitoring in treated wheat flour. The analyte was extracted from wheat flour by a single step solid–liquid extraction by using ethyl acetate and subsequently cleaned up using the Primary Secondary Amine as a sorbent prior to GC–MS analysis. The present method provides sufficient sensitivity as reflected by the values of limit of detection (LOD) and limit of quantification (LOQ), 5 ng/mL (S/N ∼3) and 50 ng/mL (the lowest validation point on the calibration curve), respectively. The calibration curve showed an excellent linearity in the concentration range of 50–1000 ng/mL (r2 = 0.998). The average recovery for spiked samples at three concentrations (150, 300, and 450 ng/g) was 98.23 ± 2.52% R.S.D. The method was applied for the determination of lufenuron residues in treated wheat flour samples. Simultaneous determination of bio-efficacy of lufenuron residues was also carried out against the red flour beetle, Tribolium castaneum to correlate the actual residual effect of lufenuron as detected by the analytical method, over a period of 3 months. The findings revealed that the residual concentration of lufenuron were neither uniform nor in descending order over a period of 3 months in wheat flour, possibly because of an uneven dispersal in the treated wheat which was subsequently milled into flour, as confirmed by GC–MS analysis. However, the residues of lufenuron were sufficient to produce 100% mortality of T. castaneum larvae up to 3 months. The results have been discussed in view of the potential of lufenuron as a candidate molecule for the control of stored product pests.

Background: Genome assembly remains an unsolved problem. Assembly projects face a range of hurdles that confound assembly. Thus a variety of tools and approaches are needed to improve draft genomes. Results: We used a custom assembly workflow to optimize consensus genome map assembly, resulting in an assembly equal to the estimated length of the Tribolium castaneum genome and with an N50 of more than 1 Mb. We used this map for super scaffolding the T. castaneum sequence assembly, more than tripling its N50 with the program Stitch. Conclusions: In this article we present software that leverages consensus genome maps assembled from extremely long single molecule maps to increase the contiguity of sequence assemblies. We report the results of applying these tools to validate and improve a 7x Sanger draft of the T. castaneum genome.

Background The red flour beetle Tribolium castaneum has developed into an insect model system second only to Drosophila. Moreover, as a coleopteran it represents the most species-rich metazoan taxon which also includes many pest species. The genetic toolbox for Tribolium research has expanded in the past years but spatio-temporally controlled misexpression of genes has not been possible so far. Results Here we report the establishment of the GAL4/UAS binary expression system in Tribolium castaneum. Both GAL4Δ and GAL4VP16 driven by the endogenous heat shock inducible promoter of the Tribolium hsp68 gene are efficient in activating reporter gene expression under the control of the Upstream Activating Sequence (UAS). UAS driven ubiquitous tGFP fluorescence was observed in embryos within four hours after activation while in-situ hybridization against tGFP revealed expression already after two hours. The response is quick in relation to the duration of embryonic development in Tribolium...

The red flour beetle, Tribolium castaneum, is an established genetically tractable model insect for evolutionary and developmental studies. Therefore, it may also represent a valuable model for comparative analysis of insect immunity. Here, we used the suppression subtractive hybridization method to identify Tribolium genes that are transcriptionally induced in response to injection of crude lipopolysaccharide (LPS). Determined genes encode proteins that share sequence similarities with counterparts from other insects known to mediate sensing of infection (e.g. Toll and PGRP) or to represent potential antimicrobial effectors (e.g. ferritin, c-type lysozyme, serine proteinase inhibitors, and defensins). Especially significant is the identification of thaumatin-like peptides, representing ancient antifungal peptides originally reported from plants, that are absent from the genomes of many other insects such as Drosophila, Anopheles, and Apis. We produced recombinant thaumatin-1 in bacteria and we found that it represents an antimicrobial peptide against filamentous fungi in Tribolium. Additionally, septic injury induces expression of genes involved in stress adaptation (e.g. heat-shock proteins) or insecticide resistance (e.g. cytochrome P450s) in Tribolium, suggesting that there may be crosstalk between the immune and stress responses.

The neuropeptidergic system in insects is an excellent target for pest control strategies. One promising biorational approach is the use of peptidomimetics modified from endogenous ligands to enhance biostability and bioavailability. In this study, we functionally characterized five different G protein-coupled receptors in a phylogenetic cluster, containing receptors for PRXamide in the red flour beetle Tribolium castaneum, by evaluating a series of 70 different peptides and peptidomimetics. Three pyrokinin receptors (TcPKr-A, -B, and -C), cardioacceleratory peptide receptor (TcCAPAr) and ecdysis triggering hormone receptor (TcETHr) were included in the study. Strong agonistic or antagonistic peptidomimetics were identified, and included beta-proline (β(3)P) modification of the core amino acid residue proline and also a cyclo-peptide. It is common for a ligand to act on multiple receptors. In a number of cases, a ligand acting as an agonist on one receptor was an efficient antagonis...

Tribolium flour beetles produce defensive compounds, including quinones, putatively aimed at deterring predators and inhibiting microbes. Here we examine how effective the defensive secretions of Tribolium confusum and T. castaneum are at inhibiting growth of various microbes and how this varies with species, geographic strain, and sex of the beetles. We explore differences at both the kingdom and species level of common flour microbes in their susceptibility to defensive compounds. Beetle species and strains vary in their ability to inhibit microbial growth. In addition, microbes vary in their sensitivity to the beetles' defense compounds. The capability to suppress microbial growth is likely under stabilizing selection with optimum quinone production varying among populations and may be dependent on several environmental factors including temperature, humidity, and predators.

In the milling industry, the Tribolium confusum is hard to exterminate pest. We measured the concentration time
product (Ct-P) achieved during the hydrogen cyanide (HCN) fumigation and examined whether the Ct-P levels in the
explored Czech pilot mill were sufficient to control the field strain of T. confusum. Using an originally constructed,
gastight fumigation chamber, it was estimated that the Ct-P required for the complete killing of the field strain of
T. confusum was 4× higher (4.35 g/h/m3) than the levels required to kill the laboratory strain (1.25 g/h/m3). The Ct-P
levels (ranging from 79 g/h/m3 to 100 g/h/m3) reached during the mill fumigations with HCN were less than half of
the labelled HCN rate (240 g/h/m3). Nevertheless, the current HCN dosage is still sufficient since the Ct-P reached
during the mill fumigations was at least 99× higher than that required for the exterminating to the lab strain and 18×
higher than that required for the field strain extermination. These results were confirmed in mill validation testing,
where 100% mortality of T. confusum adults was achieved

Ethanol extract of plants Cestrum nocturnum and Cestrum diurnum were studied for their effect on the stored grain pest Tribolium confusum and Tribolium castaneum (Herbst). Effect of the plants extract on duration of last instars larval period, % of
emergence, weight and mortality of T. castaneum and T. confusum was evaluated and statistical analysed and graphically presented. Insecticidal effect varies with cestrum
species. Comparatively alcoholic extract showed remarkable insecticidal activity than the aqueous extract against Tribolium sp. Extract incorporated diet when fed to larvae the growth was significantly inhibited. Devlopment of insect was abstracted due to the extracts of Cestrum sp. These plant extracts could be useful for controlling the store grain
pest T. castaneum and T. confusum.

Plants are very useful, self-generating machines, producing a variety of useful bioactive products. Keeping in view this idea, the crude methanolic extract and various fractions of Zizyphus jujuba were screened for antifungal, cytotoxic, antitermite and insecticidal activities. Low activity was shown by the crude methanolic extract (12%), n-hexane (9%), chloroform (20%) and ethyl acetate (14%) fraction against Penicillium notatum. Low activity was shown by the n-hexane fraction against Aspergillus niger (10%) and Trichoderma harzianum (13%) and inactive against Aspergillus flavus, Fusarium oxysporum and Rhizopus stolonifer. The CHCl(3) fraction exhibited low activity of 10% against F. oxysporum while showing no activity against the rest of the test fungi. All the test samples were inactive against Rhizopus stolonifer. The crude methanolic extract was highly cytotoxic (73.33%) at the concentration of 1000 (µg/ml) while the rest of the test samples were low in toxicity at the same con...

In the last decades lectins have received a lot of attention as potential tools in pest control. Despite substantial progress in the field not all the factors determining insecticidal potency and selectivity of these proteins have been described. Recently, three lectins, RSA (Rhizoctonia solani agglutinin), SNA-I and SNA-II (Sambucus nigra agglutinin I and II) have been shown to be toxic to aphids and caterpillars. In this project we investigated if these lectins are also toxic against larvae and a cell line of the red flour beetle, Tribolium castaneum, a model organism and important pest of stored products. Furthermore, we analyzed the stability of the lectins in the larval gut and used confocal microscopy to compare their efficiency in passing through the peritrophic matrix (PM). We observed that all three lectins were toxic against the T. castaneum cell line and their effectiveness in vitro was in decreasing order SNA-II>SNA-I>RSA with the respective EC50 being 0.1, 0.5 and...

Analysis of arrangement of satellite DNA sequences in Tribolium madens (Insecta, Coleoptera) by Southern analysis of pulsed-field blots and two colour FISH on extended chromosomes and DNA fibres revealed a novel type of heterochromatin organization. Two satellite DNAs, distributed over the whole pericentromeric heterochromatin of all chromosomes form clusters, ranging in size from 150 kb up to several Mb. Within the clusters, both satellites are in the form of highly interspersed, short homogeneous arrays which vary in size with a lowest length limit of only few kb. The longest arrays composed of a single satellite are relatively short, up to 70 kb for satellite I, and up to 45 kb for satellite II. Only a small fraction of about 15% of satellite II is organized in long tandem repeats, while the rest is in the form of only a few repeats intermingled with satellite I. The results indicate that large clusters composed of interspersed arrays of both satellites represent a major componen...

Eight eudesmane and eremophilane sesquiterpenes administered to Tribolium castaneum larvae caused different allelochemical effects. Topical application of 3-oxo-γ-costic acid produced the greatest lengthening in the duration of the pupal stage. Morphological deformities were found, specifically when ilicic, costic, and γ-costic acids and costic aldehyde were used. Ilicic acid exhibited the major toxicity 72 hr following topical application. All compounds were significantly toxic at the end point of the experiment (60 days). Treated surface toxicity was lower than when topical assays were carried out. Responses to tessaric acid in choice bioassays had the highest attractive effect. Maximum repellency was caused by the 3-oxo-γ-costic acid. However, experimental series carried out using γ-costic acid, eremophilan-1(10),2,11(13)-trien-12-oic acid, costic aldehyde, and ilicic aldehyde showed no clear response.