Abstract:Histological and ultrastrucutural alterations in the midgut of Aedes albopictus larvae infected with Bacillus thuringiensis var. israelensis (Bti) were observed by light and transmission electron microscopy (TEM). Two formulations of Bti were used: granulated and powder, with 0.2% active ingredient in 90 larvae of Ae. albopictus distributed in three containers containing 30 larvae each (one control group and two test groups). The midgut epithelium of the control group presented flattened and elongated cells wi… Show more
“…5 a). The results are in accordance with previous reports 61 . The toxicity of the plant essential oil (EO) as an insecticide mainly depends on penetration rate of EO into the insect body, their interaction with specific target enzymes and the detoxification ability of the mosquito at each developmental stage 62 .…”
Section: Resultssupporting
confidence: 94%
“…Some earlier researchers have also reported the morphological aberrations induced by nano based botanical pesticide on mosquito larvae 11 , 63 . The comparatively severe damage occurred in the larval midgut cells treated with nano-CWO may attributed to the remarkable feature of nanoparticles; larger surface and smaller size, which can promote easy penetration into the larval body and disturb their normal cycle of life by interrupting the intake of feed, cell division and breathing, the statement is supported by previous literature 61 , 64 . Figure 5 Cytomorphology of midgut of larva ( A ) Control ( B ) CWO nanocapsules, magnification 40×.…”
Section: Resultssupporting
confidence: 62%
“…(EC). EC is responsible for the production of enzymes and cuticular oxidation process 61 and have several diverse functions, such as ionic and osmotic regulation, lipid and carbohydrate storage, midgut lumen pH control, digestive enzyme secretion and nutrient absorption 62 . The 4th instar larvae of An.…”
The use pesticide is one of the indispensable means to combat mosquito borne diseases. However, the repeated use of synthetic pesticides has induced resistance in the vector pest along with undesirable impact on the environment. The biodegradability, non-persistent and user's safety are the root cause to prefer plant-derived pesticides to synthetic ones. The botanical based pesticides tend to degrade rapidly under the influence of several environmental factors. For the feasible application as pesticides, the plant products are formulated either as liquid or as purely solid. Despite well-established formulation technology in pesticide delivery, their handling trouble is being ignored. There is difficulty in liquid formulation of pesticide products, as they are prone to splashing and spillage, resulting in contamination, wastage and direct exposure to skin; whereas a solid formulation tends to produce dust. In the present work, cedarwood (Cedrus deodara) essential oil embedded pectin nanocapsules were produced. The nanocapsules were characterized according to their morphology, size, encapsulation efficiency and thermal stability. Furthermore, the nanocapsules were impregnated onto mini cotton tea bags to be employed as RTU (ready to use) formulation for treating the breeding sites of mosquitoes. The larvicidal activity of the bags treated with pectin-cedar wood nanocapsules was assessed against malaria vector, Anopheles culicifacies and 98% mortality was recorded till 4 weeks, this suggests its potential and hassle free applications in controlling mosquito vector. Global health threats, primarily due to mosquito borne diseases can devastate communities in social and economic terms and hinder development progress 1. Among the various vector borne diseases, malaria is the major public health issue, which transmits through the bite of Anopheles mosquitoes 2. According to the World Health Organization (WHO) 2019 report, malaria causes 228 million morbidity cases and 405,000 number of mortality 3. Anopheles culicifacies is alone accountable for 60-65% of the malaria burden 4. A Mosquito-borne disease remains a challenge since there is no vaccine, and further drug resistance is an increasing threat. Under these circumstances, vector control plays a vital role and often remains the only way to prevent disease outbreaks. The control of malaria vector, Anopheles, relies upon indoor residual spray (IRS) and insecticide treated nets (ITN) 5. Several other control tools have also been proposed including; nano pesticides, microbial pesticides (that are natural occurring bacteria, fungi and viruses) and pesticides of plant origin, which may act as repellents, oviposition deterrents and larvicides etc. 6,7. A new generation biotechnological tool in mosquito control program, based on genetically modified mosquitoes and sterile Insect Technique (SIT) is also being considered 7,8. Despite significant progress so far, further investigations are needed to determine if genetically modification based strategies can be an effective metho...
“…5 a). The results are in accordance with previous reports 61 . The toxicity of the plant essential oil (EO) as an insecticide mainly depends on penetration rate of EO into the insect body, their interaction with specific target enzymes and the detoxification ability of the mosquito at each developmental stage 62 .…”
Section: Resultssupporting
confidence: 94%
“…Some earlier researchers have also reported the morphological aberrations induced by nano based botanical pesticide on mosquito larvae 11 , 63 . The comparatively severe damage occurred in the larval midgut cells treated with nano-CWO may attributed to the remarkable feature of nanoparticles; larger surface and smaller size, which can promote easy penetration into the larval body and disturb their normal cycle of life by interrupting the intake of feed, cell division and breathing, the statement is supported by previous literature 61 , 64 . Figure 5 Cytomorphology of midgut of larva ( A ) Control ( B ) CWO nanocapsules, magnification 40×.…”
Section: Resultssupporting
confidence: 62%
“…(EC). EC is responsible for the production of enzymes and cuticular oxidation process 61 and have several diverse functions, such as ionic and osmotic regulation, lipid and carbohydrate storage, midgut lumen pH control, digestive enzyme secretion and nutrient absorption 62 . The 4th instar larvae of An.…”
The use pesticide is one of the indispensable means to combat mosquito borne diseases. However, the repeated use of synthetic pesticides has induced resistance in the vector pest along with undesirable impact on the environment. The biodegradability, non-persistent and user's safety are the root cause to prefer plant-derived pesticides to synthetic ones. The botanical based pesticides tend to degrade rapidly under the influence of several environmental factors. For the feasible application as pesticides, the plant products are formulated either as liquid or as purely solid. Despite well-established formulation technology in pesticide delivery, their handling trouble is being ignored. There is difficulty in liquid formulation of pesticide products, as they are prone to splashing and spillage, resulting in contamination, wastage and direct exposure to skin; whereas a solid formulation tends to produce dust. In the present work, cedarwood (Cedrus deodara) essential oil embedded pectin nanocapsules were produced. The nanocapsules were characterized according to their morphology, size, encapsulation efficiency and thermal stability. Furthermore, the nanocapsules were impregnated onto mini cotton tea bags to be employed as RTU (ready to use) formulation for treating the breeding sites of mosquitoes. The larvicidal activity of the bags treated with pectin-cedar wood nanocapsules was assessed against malaria vector, Anopheles culicifacies and 98% mortality was recorded till 4 weeks, this suggests its potential and hassle free applications in controlling mosquito vector. Global health threats, primarily due to mosquito borne diseases can devastate communities in social and economic terms and hinder development progress 1. Among the various vector borne diseases, malaria is the major public health issue, which transmits through the bite of Anopheles mosquitoes 2. According to the World Health Organization (WHO) 2019 report, malaria causes 228 million morbidity cases and 405,000 number of mortality 3. Anopheles culicifacies is alone accountable for 60-65% of the malaria burden 4. A Mosquito-borne disease remains a challenge since there is no vaccine, and further drug resistance is an increasing threat. Under these circumstances, vector control plays a vital role and often remains the only way to prevent disease outbreaks. The control of malaria vector, Anopheles, relies upon indoor residual spray (IRS) and insecticide treated nets (ITN) 5. Several other control tools have also been proposed including; nano pesticides, microbial pesticides (that are natural occurring bacteria, fungi and viruses) and pesticides of plant origin, which may act as repellents, oviposition deterrents and larvicides etc. 6,7. A new generation biotechnological tool in mosquito control program, based on genetically modified mosquitoes and sterile Insect Technique (SIT) is also being considered 7,8. Despite significant progress so far, further investigations are needed to determine if genetically modification based strategies can be an effective metho...
“…israelensis (Bti) were observed by Silva et al (2008). After Bti ingestion, the intestinal cells showed a disorganization of the basal processes, dilatation and fragmentation of the rough endoplasmic reticulum, with intense cytoplasmic vacuolization.…”
The Culicidae are biting insects that are most harmful to people. They are almost all blood-suckers, and are responsible for the spread of many important diseases such as malaria, yellow fever and elephantiasis. Entomopathogenic microorganisms occupy an important place among the alternative methods of fighting against pests insect. The fungus, Beauveria bassiana is an entomopathogenic agent naturally present in the ecosystems and offers a very interesting potential for controlling populations of mosquitoes. Our study aims at showing the 4 th stage larvae histological changes of the domestic mosquito Culex pipiens, treated with the entomopathogenic fungus B. bassiana in suspension which corresponds to a dose of 10 7 spore/mL. In fact, after developing the individuals in the fungal solution, histological study was carried out on the following parts; cuticle, intestine, adipose tissue and hemolymph. The histological studies showed many alterations and malformation in the treated 4 th instar larvae body and tissues. The infection affected the different parts of the body, especially the cuticle, the adipose cells, and midgut, in addition to the development and the colonization of B. bassiana inside tissues. The application of B. bassiana on the cuticle of the larvae was dependent on an apparent disturbance in the structure of the cuticle or the degeneration of its different parts. The fungus infection does not stop at the level of the body walls, so it even goes to adipose tissue, epidermal cells and intestine. Based on these results, B. bassiana could be suggested as suitable biocontrol agent against C. pipiens.
“…Similar results as ours were obtained in histological analyses of Culex nigripalpus larvae infected by Bacillus thuringiensis medellin (Cry11Bb) [36] and in intestinal cells of larvae of Aedes albopictus infected with B. thuringiensis var. israelensis (Bti) [37]. The authors reported as signs of infection, the presence of rounded cells, cytoplasm with granules, clear or absent nucleus and extensive cytoplasmic vacuolization of epithelial cells of the mesentery of these larvae.…”
BackgroundThe dengue mosquito Aedes aegypti Linnaeus, 1762 is a widespread insect pest of serious medical importance. Since no effective vaccine is available for treating dengue, the eradication or control of the main mosquito vector is regarded as essential. Since conventional insecticides have limited success, plants may be an alternative source of larvicidal agents, since they contain a rich source of bioactive chemicals. The aim of this study was to evaluate the larvicidal activity of the neolignan burchellin isolated from Ocotea cymbarum (Lauraceae), a plant from the Amazon region, against third instar larvae of A. aegypti.MethodsBurchellin obtained from O. cymbarum was analyzed. The inhibitory activity against A. aegypti eggs and larvae and histological changes in the digestive system of treated L3 larvae were evaluated. In addition, nitric oxide synthase activity and nitric oxide levels were determined, and cytotoxicity bioassays performed.ResultsThe data showed that burchellin interfered with the development cycle of the mosquito, where its strongest toxic effect was 100% mortality in larvae (L3) at concentrations ≥ 30 ppm. This compound did not show target cell toxicity in peritoneal macrophages from BALB/c mice, and proved to have molecular stability when dissolved in water. The L3 and L4 larvae treated with the compound showed cellular destruction and disorganization, cell spacing, and vacuolization of epithelial cells in small regions of the midgut.ConclusionThe neolignan burchellin proved to be a strong candidate for a natural, safe and stable phytolarvicidal to be used in population control of A. aegypti.
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