Sequence analysis and molecular characterization of larval midgut cDNA transcripts encoding peptidases from the yellow mealworm, Tenebrio molitor L.

Department of Entomology, Kansas State University, Manhattan, KS, USA.
Insect Molecular Biology (Impact Factor: 3.04). 09/2007; 16(4):455-68. DOI: 10.1111/j.1365-2583.2007.00740.x
Source: PubMed

ABSTRACT Peptidase sequences were analysed in randomly picked clones from cDNA libraries of the anterior or posterior midgut or whole larvae of the yellow mealworm, Tenebrio molitor Linnaeus. Of a total of 1528 sequences, 92 encoded potential peptidases, from which 50 full-length cDNA sequences were obtained, including serine and cysteine proteinases and metallopeptidases. Serine proteinase transcripts were predominant in the posterior midgut, whereas transcripts encoding cysteine and metallopeptidases were mainly found in the anterior midgut. Alignments with other proteinases indicated that 40% of the serine proteinase sequences were serine proteinase homologues, and the remaining ones were identified as either trypsin, chymotrypsin or other serine proteinases. Cysteine proteinase sequences included cathepsin B- and L-like proteinases, and metallopeptidase transcripts were similar to carboxypeptidase A. Northern blot analysis of representative sequences demonstrated the differential expression profile of selected transcripts across five developmental stages of Te. molitor. These sequences provide insights into peptidases in coleopteran insects as a basis to study the response of coleopteran larvae to external stimuli and to evaluate regulatory features of the response.

  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Tenebrio molitor, Zophobas morio, Alphitobius diaperinus, Acheta domesticus and Blaptica dubia were evaluated for their potential as a future protein source. Crude protein content ranged from 19% to 22% (Dumas analysis). Essential amino acid levels in all insect species were comparable with soybean proteins, but lower than for casein. After aqueous extraction, next to a fat fraction, a supernatant, pellet, and residue were obtained, containing 17-23%, 33-39%, 31-47% of total protein, respectively. At 3% (w/v), supernatant fractions did not form stable foams and gels at pH 3, 5, 7, and 10, except for gelation for A. domesticus at pH 7. At 30% w/v, gels at pH 7 and pH 10 were formed, but not at pH 3 and pH 5. In conclusion, the insect species studied have potential to be used in foods due to: (1) absolute protein levels; (2) protein quality; (3) ability to form gels.
    Food Chemistry 12/2013; 141(4):3341-8. · 3.33 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: This study describes the design, synthesis and use of selective peptide substrates for cysteine peptidases of the C1 papain family, important in many biological processes. The structure of the newly synthesized substrates is Glp-Xaa-Ala-Y, where: Glp=pyroglutamyl; Y=pNA (p-nitroanilide), AMC (4-amino-7-methylcoumaride) or AFC (4-amino-7-trifluoromethyl-coumaride); Xaa=Phe, Val. Substrates were synthesized enzymatically to guarantee selectivity of the reaction and optical purity of the target compounds, simplifying the scheme of synthesis and isolation of products. The hydrolysis of the synthesized substrates was evaluated by C1 cysteine peptidases from different organisms and with different functions, including plant enzymes papain, bromelain, ficin; and mammalian lysosomal cathepsins B and L. The new substrates were selective for C1 cysteine peptidases and were not hydrolyzed by serine, aspartic, or metallo peptidases. We demonstrated an application of the selectivity of the synthesized substrates during the chromatographic separation of a multi-component set of digestive peptidases from a beetle, Tenebrio molitor. Used in combination with the cysteine peptidase inhibitor E-64, these substrates were able to differentiate cysteine peptidases from peptidases of other classes in midgut extracts from T. molitor larvae and larvae of the genus Tribolium, and thus are useful in the analysis of complex mixtures containing peptidases from different classes.
    Analytical Biochemistry 01/2014; · 2.58 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Superoxide dismutase (SOD) is an antioxidant enzyme involved in detoxifying reactive oxygen species. In this study, we identified genes encoding the extracellular and intracellular copper-zinc SODs (ecCuZnSOD and icCuZnSOD) and a manganese SOD (MnSOD) in the yellow mealworm beetle, Tenebrio molitor. The cDNAs for ecCuZnSOD, icCuZnSOD, and MnSOD, respectively, encode 24.55, 15.81, and 23.14 kDa polypeptides, which possess structural features typical of other insect SODs. They showed 20–94% identity to other known SOD sequences from Bombyx mori, Musca domestica, Nasonia vitripennis, Pediculus humanus corporis, and Tribolium castaneum. Expression of these genes was analyzed in selected tissues and developmental stages, and following exposure to Escherichia coli and parasitization by Scleroderma guani. We recorded expression of all three SODs in cuticle, fat body, and hemocytes and in the major developmental stages. Relatively higher expressions were detected in late-instar larvae and pupae, compared to other developmental stages. Transcriptional levels were upregulated following bacterial infection. Analysis of pupae parasitized by S. guani revealed that expression of T. molitor SOD genes was significantly induced following parasitization. We infer that these genes act in immune response and in host–parasitoid interactions.
    Archives of Insect Biochemistry and Physiology 07/2014; · 1.52 Impact Factor

Full-text (2 Sources)

Available from
Jun 5, 2014