N-glycosylation influences the catalytic activity of mosquito α-glucosidases associated with susceptibility or refractoriness to Lysinibacillus sphaericus

Nascimento, Nathaly Alexandre do; Ferreira, Lígia Maria; Romão, Tatiany Patrícia; Correia, Darleide Maria da Conceição; Vasconcelos, Crhisllane Rafaele dos Santos; Rezende, Antônio Mauro; Costa, Samara G.; Genta, Fernando Ariel; Neto, Osvaldo P. de Melo; Silva-Filha, Maria Helena Neves Lobo

doi:10.1016/j.ibmb.2016.12.009

Cited by 8 publications

(9 citation statements)

References 40 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…cazy.org), which are characterized by a (⊎/⊍) eight-barrel fold. 25,34 The catalytic activity of Cqm1 has been demonstrated in previous studies 35,36 suggesting that this enzyme can participate in carbohydrate digestion. However, the contribution of Cqm1 to the total ⊍-glucosidase activity produced by larvae remains to be analyzed, as most studies have focused on ⊍-glucosidases expressed by adults.…”

Section: Discussionmentioning

confidence: 78%

Molecular and biological features of Culex quinquefasciatus homozygous larvae for two cqm1 alleles that confer resistance to Lysinibacillus sphaericus larvicides

Menezes

Nascimento

Paiva-Cavalcanti

et al. 2021

Pest Management Science

View full text Add to dashboard Cite

BACKGROUND: Culex quinquefasciatus resistance to the binary toxin from Lysinibacillus sphaericus larvicides can occur because of mutations in the cqm1 gene that prevents the expression of the toxin receptor, Cqm1 ⊍-glucosidase. In a resistant laboratoryselected colony maintained for more than 250 generations, cqm1 REC and cqm1 REC-2 resistance alleles were identified. The major allele initially found, cqm1 REC , became minor and was replaced by cqm1 REC-2 . This study aimed to investigate the features associated with homozygous larvae for each allele to understand the reasons for the allele replacement and to generate knowledge on resistance to microbial larvicides. RESULTS: Homozygous larvae for each allele were compared. Both larvae displayed the same level of resistance to the binary toxin (3500-fold); therefore, a change in phenotype was not the reason for the replacement observed. The lack of Cqm1 expression did not reduce the total specific ⊍-glucosidase activity for homozygous cqm1 REC and cqm1 REC-2 larvae, which were statistically similar to the susceptible strain, using artificial or natural substrates. The expression of eight Cqm1 paralog ⊍-glucosidases was demonstrated in resistant and susceptible larvae. Bioassays in which cqm1 REC or cqm1 REC-2 homozygous larvae were reared under stressful conditions showed that most adults produced were cqm1 REC-2 homozygous (69%). Comparatively, in the offspring of a heterozygous sub-colony reared under optimal conditions for 20 generations, the cqm1 REC allele assumed a higher frequency (0.72). CONCLUSION: Homozygous larvae for each allele exhibited a similar resistant phenotype. However, they presented specific advantages that might favor their selection and can be used in designing resistance management practices.

show abstract

Section: Discussionmentioning

confidence: 78%

Molecular and biological features of Culex quinquefasciatus homozygous larvae for two cqm1 alleles that confer resistance to Lysinibacillus sphaericus larvicides

Menezes

Nascimento

Paiva-Cavalcanti

et al. 2021

Pest Management Science

View full text Add to dashboard Cite

show abstract

“…The α-glucosidases from mosquito larvae have been poorly characterized [ 153 ]. However, the catalytic activity of the native or recombinant Cqm1 was demonstrated, indicating its potential ability to participate in carbohydrate digestion [ 154 , 155 , 156 ].…”

Section: Toxins and Mode Of Actionmentioning

confidence: 99%

“…Their expression as midgut membrane-bound proteins is essential for the binding to the Bin toxin, and gene mutations that disrupt their expression as GPI-anchored proteins have been recognized as the most important mechanism that confers resistance to the Bin toxin in mosquitoes (see Section 4 ). The expression of Cqm1 recombinant proteins in some cell lines has been used to demonstrate its capacity to bind to the bin toxin, to mediate the cytopathological effects, and to assess its catalytic activity [ 154 , 155 , 156 , 157 , 158 ]. Functional assays using such recombinant proteins showed that the N-terminal region of Cqm1 is required for its binding to the Bin toxin [ 154 ].…”

Section: Toxins and Mode Of Actionmentioning

confidence: 99%

Bacterial Toxins Active against Mosquitoes: Mode of Action and Resistance

Silva-Filha

Romão

Rezende

et al. 2021

Toxins

Self Cite

View full text Add to dashboard Cite

Larvicides based on the bacteria Bacillus thuringiensis svar. israelensis (Bti) and Lysinibacillus sphaericus are effective and environmentally safe compounds for the control of dipteran insects of medical importance. They produce crystals that display specific and potent insecticidal activity against larvae. Bti crystals are composed of multiple protoxins: three from the three-domain Cry type family, which bind to different cell receptors in the midgut, and one cytolytic (Cyt1Aa) protoxin that can insert itself into the cell membrane and act as surrogate receptor of the Cry toxins. Together, those toxins display a complex mode of action that shows a low risk of resistance selection. L. sphaericus crystals contain one major binary toxin that display an outstanding persistence in field conditions, which is superior to Bti. However, the action of the Bin toxin based on its interaction with a single receptor is vulnerable for resistance selection in insects. In this review we present the most recent data on the mode of action and synergism of these toxins, resistance issues, and examples of their use worldwide. Data reported in recent years improved our understanding of the mechanism of action of these toxins, showed that their combined use can enhance their activity and counteract resistance, and reinforced their relevance for mosquito control programs in the future years.

show abstract

“…quinquefasciatus larvae requires protoxin ingestion, midgut processing of protoxin into toxin by serine-proteases [5] and specific binding to midgut-bound receptors [6]. These receptors were identified as Cqm1 glycosylphosphatidylinositol (GPI) anchored α-glucosidases [7, 8], maltases that may play roles in the metabolism of carbohydrates [9, 10]. Binding of the Bin toxin to the Cqm1 receptors allows it to form pores and penetrate the membranes of midgut-cells [11–13].…”

Section: Introductionmentioning

confidence: 99%

A differential transcriptional profile by Culex quinquefasciatus larvae resistant to Lysinibacillus sphaericus IAB59 highlights genes and pathways associated with the resistance phenotype

Rezende

Wallau

et al. 2019

Parasites Vectors

Self Cite

View full text Add to dashboard Cite

Background The study of the mechanisms by which larvae of the Culex quinquefasciatus mosquito survive exposure to the entomopathogen Lysinibacillus sphaericus has benefited substantially from the generation of laboratory-selected colonies resistant to this bacterium. One such colony, RIAB59, was selected after regular long-term exposure of larvae to the L. sphaericus IAB59 strain. This strain is characterized by its ability to produce the well known Binary (Bin) toxin, and the recently characterized Cry48Aa/Cry49Aa toxin, able to kill Bin-resistant larvae. Resistance to Bin is associated with the depletion of its receptor, Cqm1 α-glucosidase, from the larvae midgut. This study aimed to identify novel molecules and pathways associated with survival of the RIAB59 larvae and the resistance phenotype. Methods A transcriptomic approach and bioinformatic tools were used to compare the profiles derived from the midguts of larvae resistant and susceptible to L. sphaericus IAB59. Results The RNA-seq profiles identified 1355 differentially expressed genes (DEGs), with 673 down- and 682 upregulated transcripts. One of the most downregulated DEGs was cqm1 , which validates the approach. Other strongly downregulated mRNAs encode the enzyme pantetheinase, apolipoprotein D, lipases, heat-shock proteins and a number of lesser known and hypothetical polypeptides. Among the upregulated DEGs, the top most encodes a peroxisomal enzyme involved in lipid metabolism, while others encode enzymes associated with juvenile hormone synthesis, ion channels, DNA binding proteins and defense polypeptides. Further analyses confirmed a strong downregulation of several enzymes involved in lipid catabolism while the assignment of DEGs into metabolic pathways highlighted the upregulation of those related to DNA synthesis and maintenance, confirmed by their clustering into related protein networks. Several other pathways were also identified with mixed profiles of down- and upregulated transcripts. Quantitative RT-PCR confirmed the changes in levels seen for selected mRNAs. Conclusions Our transcriptome-wide dataset revealed that the RIAB59 colony, found to be substantially more resistant to Bin than to the Cry48Aa/Cry49Aa toxin, developed a differential expression profile as well as metabolic features co-selected during the long-term adaptation to IAB59 and that are most likely linked to Bin resistance. Electronic supplementary material The online version of this article (10.1186/s13071-019-3661-y) contains supplementary material, which is available to authorized users.

show abstract

N-glycosylation influences the catalytic activity of mosquito α-glucosidases associated with susceptibility or refractoriness to Lysinibacillus sphaericus

Cited by 8 publications

References 40 publications

Molecular and biological features of Culex quinquefasciatus homozygous larvae for two cqm1 alleles that confer resistance to Lysinibacillus sphaericus larvicides

Molecular and biological features of Culex quinquefasciatus homozygous larvae for two cqm1 alleles that confer resistance to Lysinibacillus sphaericus larvicides

Bacterial Toxins Active against Mosquitoes: Mode of Action and Resistance

A differential transcriptional profile by Culex quinquefasciatus larvae resistant to Lysinibacillus sphaericus IAB59 highlights genes and pathways associated with the resistance phenotype

Contact Info

Product

Resources

About