Aqueous suspension of ethanol extracts of Derris (Lonchocarpus) urucu (Leguminosae), collected in the state of Amazonas, Brazil, were tested for larvicidal activity against the mosquito Aedes aegypti (Diptera:Culicidae). The aim of this study was to observe the alterations of peritrophic matrix in Ae. aegypti larvae treated with an aqueous suspension of D. urucu extract. Different concentrations of D. urucu root extract were tested against fourth instar larvae. One hundred percent mortality was observed at 150 microg/ml (LC(50) 17.6 microg/ml) 24 h following treatment. In response to D. urucu feeding, larvae excreted a large amount of amorphous feces, while control larvae did not produce feces during the assay period. Ultrastructural studies showed tha larvae fed with 150 microg/ml of D. urucu extract for 4 h have an imperfect peritrophic matrix and extensive damage of the midgut epithelium. Data indicate a protective role for the peritrophic matrix. The structural modification of the peritrophic matrix is intrinsically associated with larval mortality.
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http://dx.doi.org/10.1590/s0074-02762002000300017 | DOI Listing |
mBio
January 2025
Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas, USA.
Unlabelled: Climate change is predicted to increase the spread of mosquito-borne viruses, but genetic mechanisms underlying the influence of environmental variation on the ability of insect vectors to transmit human pathogens is unknown. In response to a changing climate, mosquitoes will experience longer periods of drought. An important physiological response to dry environments is the protection against dehydration, here defined as desiccation tolerance.
View Article and Find Full Text PDFInt J Mol Sci
December 2024
Liaoning Engineering and Technology Research Center for Insect Resources, College of Bioscience and Biotechnology, Shenyang Agricultural University, Shenyang 110866, China.
Chitin deacetylases (CDAs) are carbohydrate esterases associated with chitin metabolism and the conversion of chitin into chitosan. Studies have demonstrated that chitin deacetylation is essential for chitin organization and compactness and therefore influences the mechanical and permeability properties of chitinous structures, such as the peritrophic membrane (PM) and cuticle. In the present study, two genes ( and ) encoding CDA protein isoforms were identified and characterized in Chinese oak silkworm () larvae.
View Article and Find Full Text PDFPLoS Biol
January 2025
State Key Laboratory of Genetic Engineering, School of Life Sciences, Department of Infectious Diseases, Zhongshan Hospital, Fudan University, Shanghai, China.
The peritrophic matrix (PM) acts as a physical barrier that influences the vector competence of mosquitoes. We have previously shown that gut microbiota promotes PM formation in Anopheles stephensi, although the underlying mechanisms remain unclear. In this study, we identify that the cell wall components of gut commensal bacteria contribute to PM formation.
View Article and Find Full Text PDFFront Immunol
December 2024
Key Laboratory of Freshwater Fisheries and Germplasm Resources Utilization, Ministry of Agriculture and Rural Affairs, Freshwater Fisheries Research Center, Chinese Academy of Fishery Sciences, Wuxi, China.
Introduction: This study aimed to investigate the effects of a low-fishmeal diet (LF, substituting soybean meal for 40% fish meal) and the supplementation of 500 mg/kg and 1000 mg/kg Yu Ping Feng (YPF) polysaccharides on the growth performance, antioxidant enzyme activities, intestinal ultrastructure, non-specific immunity, and microbiota of .
Methods: The study involved the administration of different diets to M. rosenbergii, including a control diet, a low-fishmeal diet (LF), and LF diets supplemented with 500 mg/kg and 1000 mg/kg YPF polysaccharides.
Insect Sci
November 2024
MOE Key Laboratory of Bio-Intelligent Manufacturing, School of Bioengineering, Dalian University of Technology, Dalian, Liaoning Province, China.
Insect lytic polysaccharide monooxygenases (LPMO15s) are newly discovered copper-dependent enzymes that promote chitin degradation in insect through oxidative cleavage of glycosidic bonds. They are potential pesticide targets due to their critical role for chitin turnover in the integument, trachea, and peritrophic matrix of the midgut during insect molting. However, the knowledge about whether and how LPMO15s participate in chitin turnover in other tissues is still insufficient.
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