Chitinolytic activities in the gut of Aedes aegypti (Diptera:Culicidae) larvae and their role in digestion of chitin-rich structures

Souza-Neto, Jayme A.; Gusmão, Desiely Silva; Lemos, Francisco José Alves

doi:10.1016/s1095-6433(03)00224-1

Cited by 15 publications

(14 citation statements)

References 27 publications

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“…The first step in the mode of action of Cyt1Aa is its solubilization in the alkaline pH of the midgut of susceptible larvae [25]. Lepidopteran insects have alkaline pH from 8 to 10 in the different midgut regions similar to that in dipteran larvae, although the pH gradients encountered throughout the larval gut is different in both insect orders [11, 26]. To determine if Cyt1Aa solubilization could be a limiting step at certain pH’s, Cyt1Aa crystals were solubilized at different pH’s.…”

Section: Resultsmentioning

confidence: 99%

Membrane binding and oligomer membrane insertion are necessary but insufficient for Bacillus thuringiensis Cyt1Aa toxicity

et al. 2014

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Bacillus thuringiensis Cyt proteins are pore-forming toxins that have insecticidal activity mainly against dipteran insects. However, certain Cyt proteins have toxicity to some insect orders, but not toxicity of Cyt1Aa against lepidopteran larvae has been found. Insect specificity has been proposed to rely in specific binding to certain lipids on the brush border membrane of midgut cells since no protein receptors have been described so far. To determine the molecular basis of Cyt1Aa insect specificity we compared different steps of Cyt1Aa mode of action in a susceptible insect as the dipteran Aedes aegypti and also in the non-susceptible lepidopteran Manduca sexta. Our data shows that the lack toxicity of Cyt1Aa to M. sexta larvae does not rely on protoxin processing, membrane binding interaction, and oligomerization of Cyt1Aa since these steps were similar in the two insect species analyzed.

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Section: Resultsmentioning

confidence: 99%

Membrane binding and oligomer membrane insertion are necessary but insufficient for Bacillus thuringiensis Cyt1Aa toxicity

et al. 2014

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“…Chitin is an insoluble structural polysaccharide that is important as a supporting element in arthropod exoskeleton (Neville et al, 1976), fungal and bacterial cell walls (Debono and Gordee, 1994;Gomaa, 2012), microfilaria sheath (Araujo et al, 1993) and the lining of the digestive tracts of many arthropods (Souza-Neto et al, 2003;Zimoch et al, 2005;Khajuria et al, 2010). Arthropod development and morphogenesis rely on remodeling chitin and in the process requires chitin synthases and chitinases to control this process (Merzendorfer and Zimoch, 2003).…”

Section: Research Articlementioning

confidence: 99%

Dual silencing of long and short Amblyomma americanum acidic chitinase forms weakens the tick cement cone stability

Kim

Curran

Mulenga

2014

Journal of Experimental Biology

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This study demonstrates that Amblyomma americanum (Aam) constitutively and ubiquitously expresses the long (L) and short (S) putative acidic chitinases (Ach) that are distinguished by a 210 base pair (bp) deletion in AamAch-S. Full-length AamAch-L and AamAch-S cDNA are 1959 and 1718 bp long, containing 1332 and 1104 bp open reading frames that code for 443 and 367 amino acid residues proteins with the former predicted to be extracellular and the latter intracellular. Both AamAch-L and AamAch-S mRNA are expressed in multiple organs as revealed by qualitative RT-PCR analysis. Furthermore, quantitative reverse transcription polymerase chain reaction analysis revealed that AamAch-L mRNA was downregulated in the mid-gut, but was unchanged in the salivary gland and in other organs in response to feeding. Of significant interest, AamAch-L and/or AamAch-S functions are probably associated with formation and/or maintenance of stability of A. americanum tick cement cone. Dual RNA interference silencing of AamAch-L and/or AamAch-S mRNA caused ticks to loosely attach onto host skin as suggested by bleeding around tick mouthparts and ticks detaching off host skin with a light touch. AamAch-L may apparently encode an inactive chitinase as indicated by Pichia pastoris-expressed recombinant AamAch-L failing to hydrolyse chitinase substrates. Unpublished related work in our laboratory, and published work by others that found AamAch-L in tick saliva, suggest that native AamAch-L is a non-specific immunoglobulin binding tick saliva protein in that rAamAch-L nonspecifically bound rabbit, bovine and chicken non-immune sera. We discuss findings in this study with reference to advancing knowledge on tick feeding physiology.

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“…Terra () suggested that chitinase activity in the digestive tract of insects is unlikely, because the peritrophic membrane is constructed of a framework of chitin fibers. However, chitinase occurs in the gut of Aedes aegypti (Souza‐Neto et al., ), Lacanobia oleracea (Fitches et al., ), Spodoptera frugiperda (Bolognesi et al., ), and Tenebrio molitor (Genta et al., ). Chitin polymers are split into oligomers (chitotetraose, chitotriose, chitobiose) by endochitinases (EC 3.2.1.14) (Kramer and Koga, ; Reynolds and Samuels, ), and the oligosaccharides are subsequently digested by β‐ N ‐acetylglucosaminidase (EC 3.2.1.52) to the monomer N ‐acetylglucosamine.…”

Section: Introductionmentioning

confidence: 99%

REGULATION OF AMYLASE, CELLULASE AND CHITINASE SECRETION IN THE DIGESTIVE TRACT OF THE TWO‐SPOTTED FIELD CRICKET, Gryllus bimaculatus

Weidlich

Müller

Hoffmann

et al. 2013

Arch Insect Biochem Physiol

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The secretion of amylase and cellulase in Gryllus bimaculatus is determined by increased food intake, whereby shortly after molting food consumption increases. About half of the standing amylase concentration (activity) in the endothelial cells can be secreted within 30 min. The peak of amylase and cellulase secretion that occurs in the photophase is related to the feeding peak in the previous scotophase. The secretion of chitinase on the other hand is primarily controlled by the molting cycle. Only amylase secretion was affected by calcium in the incubation medium, suggesting an apocrine release mechanism. Refeeding experiments (after 5 days without food) suggest that the release of amylase in response to a nutrient in the lumen (glucose) is not due to simple stimulation of exocytosis, but rather a stimulation of synthesis.

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Chitinolytic activities in the gut of Aedes aegypti (Diptera:Culicidae) larvae and their role in digestion of chitin-rich structures

Cited by 15 publications

References 27 publications

Membrane binding and oligomer membrane insertion are necessary but insufficient for Bacillus thuringiensis Cyt1Aa toxicity

Membrane binding and oligomer membrane insertion are necessary but insufficient for Bacillus thuringiensis Cyt1Aa toxicity

Dual silencing of long and short Amblyomma americanum acidic chitinase forms weakens the tick cement cone stability

REGULATION OF AMYLASE, CELLULASE AND CHITINASE SECRETION IN THE DIGESTIVE TRACT OF THE TWO‐SPOTTED FIELD CRICKET, Gryllus bimaculatus

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