Applications of solids NMR to the analysis of insect sclerotized structures

Kramer, Karl J.; Hopkins, Theodore L.; Schaefer, Jacob

doi:10.1016/0965-1748(95)00053-4

Cited by 158 publications

(117 citation statements)

References 28 publications

Supporting

Mentioning

113

Contrasting

Unclassified

Order By: Relevance

“…Presumably, these three phenoloxidases have other functions unrelated to cuticle tanning, although a minor, dispensable role in cuticle sclerotization and pigmentation cannot be completely ruled out. Consistent with this interpretation, laccases 2A and 2B are expressed maximally in the epidermis just before the periods of pupal and adult cuticle tanning, when they catalyze the oxidation of endogenous catechols that serve as precursors for cuticle tanning agents (4,24). Although the dsRNAmediated down-regulation of TcLac2 was incomplete, beetles injected with TcLac2 dsRNA failed to tan normally, were soft-bodied, enlarged, deformed, and unable to walk, and they subsequently died prematurely in a dsRNA dose-dependent fashion.…”

Section: Discussionmentioning

confidence: 48%

“…However, with the results reported here and elsewhere about structural cuticle proteins (4,8,25), catechols (26,27), oxidative enzymes (2,4,12), and chitin (14,17,28), as well as their interactions (3,24,29,30), researchers should in the future be able to determine more precisely how insects use these components to stabilize their exoskeletons and other tanned structures. A more complete understanding of the biochemistry of cuticle tanning, a process specific to arthropods, may reveal other targets besides laccases 2A and 2B for biorational agents that could be used for controlling agricultural pests and vectors of animal and human diseases.…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Laccase 2 is the phenoloxidase gene required for beetle cuticle tanning

Arakane

Muthukrishnan

Beeman

et al. 2005

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

353

343

View full text Add to dashboard Cite

Cuticle tanning (or sclerotization and pigmentation) in invertebrates involves the oxidative conjugation of proteins, which renders them insoluble and hardens and darkens the color of the exoskeleton. Two kinds of phenoloxidases, laccase and tyrosinase, have been proposed to participate in tanning, but proof of the true identity of the enzyme(s) responsible for this process has been elusive. We report the cloning of cDNAs for laccases and tyrosinases from the red flour beetle, Tribolium castaneum, as well as their developmental patterns of expression. To test for the involvement of these types of enzymes in cuticle tanning, we performed RNA interference experiments to decrease the levels of individual phenoloxidases. Normal phenotypes were obtained after dsRNA-mediated transcript depletion for all phenoloxidases tested, with the exception of laccase 2. Insects injected with dsRNA for the laccase 2 gene failed to tan, were soft-bodied and deformed, and subsequently died in a dsRNA dose-dependent fashion. The results presented here support the hypothesis that two isoforms of laccase 2 generated by alternative splicing catalyze larval, pupal, and adult cuticle tanning in Tribolium.exoskeleton ͉ sclerotization ͉ pigmentation ͉ Tribolium castaneum ͉ RNA interference

show abstract

Section: Discussionmentioning

confidence: 48%

Section: Discussionmentioning

confidence: 99%

Laccase 2 is the phenoloxidase gene required for beetle cuticle tanning

Arakane

Muthukrishnan

Beeman

et al. 2005

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

353

343

View full text Add to dashboard Cite

show abstract

“…Chitinases hydrolyze the structural polysaccharide chitin, a linear homopolymer of 2-acetamido-2-deoxy-D-glucopyranoside, linked by ␤-1,4-linkages, which is a component of the exoskeletons and gut linings of insects. Insect cuticles provide a physical barrier to protect the insect from pathogens or other environmental hazards and are composed primarily of chitin (76). The entomopathogenic fungi Metarhizium anisopliae, Beauvaria bassiana, Beauvaria amorpha, Verticillium lecanii, and Aspergillus flavus all secrete chitinases to break down the cuticle and enter the insect host (77).…”

Section: Figmentioning

confidence: 99%

Isolation and Characterization of Burkholderia rinojensis sp. nov., a Non-Burkholderia cepacia Complex Soil Bacterium with Insecticidal and Miticidal Activities

Córdova-Kreylos

Fernandez

Koivunen

et al. 2013

Appl Environ Microbiol

View full text Add to dashboard Cite

Isolate A396, a bacterium isolated from a Japanese soil sample demonstrated strong insecticidal and miticidal activities in laboratory bioassays. The isolate was characterized through biochemical methods, fatty acid methyl ester (FAME) analysis, sequencing of 16S rRNA, multilocus sequence typing and analysis, and DNA-DNA hybridization. FAME analysis matched A396 to Burkholderia cenocepacia, but this result was not confirmed by 16S rRNA or DNA-DNA hybridization. 16S rRNA sequencing indicated closest matches with B. glumae and B. plantarii. DNA-DNA hybridization experiments with B. plantarii, B. glumae, B. multivorans, and B. cenocepacia confirmed the low genetic similarity (11.5 to 37.4%) with known members of the genus. PCR-based screening showed that A396 lacks markers associated with members of the B. cepacia complex. Bioassay results indicated two mechanisms of action: through ingestion and contact. The isolate effectively controlled beet armyworms (Spodoptera exigua; BAW) and two-spotted spider mites (Tetranychus urticae; TSSM). In diet overlay bioassays with BAW, 1% to 4% (vol/vol) dilution of the whole-cell broth caused 97% to 100% mortality 4 days postexposure, and leaf disc treatment bioassays attained 75% ؎ 22% mortality 3 days postexposure. Contact bioassays led to 50% larval mortality, as well as discoloration, stunting, and failure to molt. TSSM mortality reached 93% in treated leaf discs. Activity was maintained in cell-free supernatants and after heat treatment (60°C for 2 h), indicating that a secondary metabolite or excreted thermostable enzyme might be responsible for the activity. Based on these results, we describe the novel species Burkholderia rinojensis, a good candidate for the development of a biocontrol product against insect and mite pests.

show abstract

“…In insects, chitin is a major component of the arthropod cuticle, and it is an integral part of peritrophic matrices (Merzendorfer, 2006). Depending on the insect species, the chitin content constitutes over 40% of the exuvial dry mass, and it varies substantially with different cuticle types, even in a single organism (Kramer et al, 1995). Thus, chitin synthesis is essential for insect development.…”

Section: Introductionmentioning

confidence: 99%

Characterization and functional analysis of a chitin synthase gene (HcCS1) identified from the freshwater pearlmussel Hyriopsis cumingii

Lin

et al. 2015

Genet. Mol. Res.

View full text Add to dashboard Cite

ABSTRACT. The triangle sail mussel, Hyriopsis cumingii, is the most important freshwater pearl mussel in China. However, the mechanisms underlying its chitin-mediated shell and nacre formation remain largely unknown. Here, we characterized a chitin synthase (CS) gene (HcCS1) in H. cumingii, and analyzed its possible physiological function. The complete ORF sequence of HcCS1 contained 6903 bp, encoding a 2300-amino acid protein (theoretical molecular mass = 264 kDa; isoelectric point = 6.22), and no putative signal peptide was predicted. A myosin motor head domain, a CS domain, and 12 transmembrane domains were found. The predicted spatial structures of the myosin head and CS domains were similar to the electron microscopic structure of the heavy meromyosin subfragment 19264-19274 (2015) of chicken smooth muscle myosin and the crystal structure of bacterial cellulose synthase, respectively. This structural similarity indicates that the functions of these two domains might be conserved. Quantitative reverse transcription PCR results showed that HcCS1 was present in all detected tissues, with the highest expression levels detected in the mantle. The HcCS1 transcripts in the mantle were upregulated following shell damage from 12 to 24 h post-damage, and they peaked (approximately 1.5-fold increase) at 12 h after shell damage. These findings suggest that HcCS1 was involved in shell regeneration, and that it might participate in shell and nacre formation in this species via chitin synthesis. HcCS1 might also dynamically regulate chitin deposition during the process of shell and nacre formation with the help of its conserved myosin head domain.

show abstract

Applications of solids NMR to the analysis of insect sclerotized structures

Cited by 158 publications

References 28 publications

Laccase 2 is the phenoloxidase gene required for beetle cuticle tanning

Laccase 2 is the phenoloxidase gene required for beetle cuticle tanning

Isolation and Characterization of Burkholderia rinojensis sp. nov., a Non-Burkholderia cepacia Complex Soil Bacterium with Insecticidal and Miticidal Activities

Characterization and functional analysis of a chitin synthase gene (HcCS1) identified from the freshwater pearlmussel Hyriopsis cumingii

Contact Info

Product

Resources

About