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Harikrishnan S, Sudarshan S, Sivasubramani K, Nandini MS, Narenkumar J, Ramachandran V, Almutairi BO, Arunkumar P, Rajasekar A, Jayalakshmi S. Larvicidal and anti-termite activities of microbial biosurfactant produced by Enterobacter cloacae SJ2 isolated from marine sponge Clathria sp. Sci Rep 2023; 13:15153. [PMID: 37704703 PMCID: PMC10499797 DOI: 10.1038/s41598-023-42475-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2023] [Accepted: 09/11/2023] [Indexed: 09/15/2023] Open
Abstract
The widespread use of synthetic pesticides has resulted in a number of issues, including a rise in insecticide-resistant organisms, environmental degradation, and a hazard to human health. As a result, new microbial derived insecticides that are safe for human health and the environment are urgently needed. In this study, rhamnolipid biosurfactants produced from Enterobacter cloacae SJ2 was used to evaluate the toxicity towards mosquito larvae (Culex quinquefasciatus) and termites (Odontotermes obesus). Results showed dose dependent mortality rate was observed between the treatments. The 48 h LC50 (median lethal concentration) values of the biosurfactant were determined for termite and mosquito larvae following the non-linear regression curve fit method. Results showed larvicidal activity and anti-termite activity of biosurfactants with 48 h LC50 value (95% confidence interval) of 26.49 mg/L (25.40 to 27.57) and 33.43 mg/L (31.09 to 35.68), respectively. According to a histopathological investigation, the biosurfactant treatment caused substantial tissue damage in cellular organelles of larvae and termites. The findings of this study suggest that the microbial biosurfactant produced by E. cloacae SJ2 is an excellent and potentially effective agent for controlling Cx. quinquefasciatus and O. obesus.
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Affiliation(s)
- Sekar Harikrishnan
- Centre of Advanced Study in Marine Biology, Faculty of Marine Sciences, Annamalai University, Parangipettai, Tamil Nadu, 608502, India.
| | - Shanmugam Sudarshan
- Department of Aquatic Environment Management, TNJFU- Dr. M.G.R Fisheries College and Research Institute, Thalainayeru, Tamil Nadu, 614712, India
| | - Kandasamy Sivasubramani
- Department of Microbiology, Faculty of Science, Annamalai University, Annamalai Nagar, Chidambaram, Tamil Nadu, India
| | - M S Nandini
- Department of Microbiology, Sree Balaji Medical College and Hospital, Chennai, Tamil Nadu, India
| | - Jayaraman Narenkumar
- Department of Environmental & Water Resources Engineering, School of Civil Engineering (SCE), Vellore Institute of Technology, Vellore, Tamil Nadu, 632014, India.
| | - Vasudevan Ramachandran
- Department of Medical Sciences, University College of MAIWP International, Taman Batu Muda, 68100, Batu Caves, Kuala Lumpur, Malaysia
- Department of Conservative Dentistry and Endodontics, Saveetha Dental College and Hospitals, Saveetha Institute of Medical and Technical Sciences, Saveetha University, Chennai, India
| | - Bader O Almutairi
- Department of Zoology, College of Science, King Saud University, 11451, Riyadh, Saudi Arabia
| | - Paulraj Arunkumar
- School of Chemical Engineering, Chonnam National University, Gwangju, South Korea
| | - Aruliah Rajasekar
- Environmental Molecular Microbiology Research Laboratory, Department of Biotechnology, Thiruvalluvar University, Serkkadu, Vellore, Tamil Nadu, 632115, India
| | - Singaram Jayalakshmi
- Centre of Advanced Study in Marine Biology, Faculty of Marine Sciences, Annamalai University, Parangipettai, Tamil Nadu, 608502, India
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Alkhaibari AM, Wood MJ, Yavasoglu SI, Bull JC, Butt TM. Optimizing the Application Timing and Dosage of Metarhizium brunneum (Hypocreales: Clavicipitaceae) as a Biological Control Agent of Aedes aegypti (Diptera: Culicidae) Larvae. JOURNAL OF MEDICAL ENTOMOLOGY 2023; 60:339-345. [PMID: 36539333 PMCID: PMC9989833 DOI: 10.1093/jme/tjac186] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Indexed: 06/02/2023]
Abstract
Aedes aegypti (Diptera: Culicidae) is the principal vector of dengue and other viruses that cause disease among 100 to 400 million people each year. The recent development of widespread insecticidal resistance has led to the rapid development of biological control solutions aimed at larval control. While the efficacy of Metarhizium brunneum has been shown against Aedes larvae, the impact of larval population dynamics will need to be determined to formulate effective control strategies. In this study, larvae were subjected to four concentrations of M. brunneum (105, 106, 107, 108 conidia ml-1). Larvae were found to be susceptible to M. brunneum with dose-dependent efficacy. When constant larval immigration was added as a parameter, peak mortality was consistently found to occur on the fourth day, before a significant reduction in control efficacy linked to a decline in conidial availability within the water column. This suggests that M. brunneum treatments should be applied at a concentration 1 × 107 conidia ml-1 every four days to effectively control mosquito larvae in the field, regardless of the fungal formulation, water volume, or larval density. Understanding fungal-mosquito dynamics is critical in developing appropriate control programs as it helps optimize the fungal control agent's dose and frequency of application.
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Affiliation(s)
| | | | - S I Yavasoglu
- Department of Biology, Faculty of Science, Aydın Adnan Menderes University, 09100, Aydın, Turkiye
| | - J C Bull
- Department of Biosciences, Faculty of Science and Engineering, Swansea University, Singleton Park, Swansea SA2 8PP, UK
| | - T M Butt
- Department of Biosciences, Faculty of Science and Engineering, Swansea University, Singleton Park, Swansea SA2 8PP, UK
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Dieng H, McLean S, Stradling H, Morgan C, Gordon M, Ebanks W, Ebanks Z, Wheeler A. Aquatain® causes anti-oviposition, egg retention and oocyte melanization and triggers female death in Aedes aegypti. Parasit Vectors 2022; 15:100. [PMID: 35317811 PMCID: PMC8939118 DOI: 10.1186/s13071-022-05202-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Accepted: 02/12/2022] [Indexed: 12/20/2022] Open
Abstract
Background In arboviral disease systems where the virus can be transmitted from male to female vectors and from one generation to the next, targeting the female (especially when she is gravid) can help alter the persistence of the virus in nature and its transmission. A typical example is Aedes aegypti, which has become unmanageable due to the development of insecticide resistance. Despite evidence that monomolecular surface films prevent the selection of genetic resistance, their potential in Aedes vector control remains largely unexplored. Methods We examined the oviposition, egg retention, oocyte melanization, and female mortality of the Cayman Islands strain of Ae. aegypti, using choice (balanced and unbalanced) and no-choice bioassays involving Aquatain® Mosquito Formulation (AMF; Aquatain Products Pty Ltd.), a polydimethylsiloxane–based liquid used for mosquito control. Results When presented with similar opportunities to oviposit in two sites treated with AMF and two other sites with untreated water (control), egg deposition rates were significantly higher in the untreated water sites than in the AMF-treated sites (P < 0.05). We also observed a matching pattern of egg deposition preference in environments with more options in terms of AMF-treated sites. Females laid significantly more eggs when water was the only available medium than when all sites were treated with AMF (P < 0.05). Also, significantly more mature eggs were withheld in the AMF no-choice environment than in the no-choice test involving only water (P < 0.05). Internal oocyte melanization was not observed in females from the oviposition arenas with the lowest AMF presence (equal-choice and water-based no-choice); in contrast, this physiological response intensified as the number of AMF-treated sites increased. Female death occurred at high rates in AMF-treated environments, and this response increased with the increasing presence of such egg deposition sites. Conclusions This study demonstrated that AMF acted as a deterrent signal to ovipositing Ae. aegypti and as an indirect adulticide. These results suggest that AMF may be a promising control tool against the dengue vector, and this warrants further evaluation under field settings. Graphical Abstract ![]()
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Affiliation(s)
- Hamady Dieng
- Mosquito Research and Control Unit (MRCU), George Town, Cayman Islands.
| | - Storm McLean
- The University College of the Cayman Islands, Olympic Way, George Town, Cayman Islands
| | | | - Cole Morgan
- The Forensic Department, Health Services Authority, George Town, Cayman Islands
| | - Malik Gordon
- The University College of the Cayman Islands, Olympic Way, George Town, Cayman Islands
| | - Whitney Ebanks
- Mosquito Research and Control Unit (MRCU), George Town, Cayman Islands
| | - Zoila Ebanks
- Mosquito Research and Control Unit (MRCU), George Town, Cayman Islands
| | - Alan Wheeler
- Mosquito Research and Control Unit (MRCU), George Town, Cayman Islands
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de Paula Siqueira T, Barbosa WF, Rodrigues EM, Miranda FR, de Souza Freitas F, Martins GF, Tótola MR. Rhamnolipids on Aedes aegypti larvae: a potential weapon against resistance selection. 3 Biotech 2021; 11:172. [PMID: 33927963 DOI: 10.1007/s13205-021-02716-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Accepted: 03/03/2021] [Indexed: 11/28/2022] Open
Abstract
The resistance of Aedes aegypti to chemical insecticides has been reported and our work proposes the use of biosurfactants as an alternative larvicide. We evaluated the effect of rhamnolipids against larvae of pyrethroid-resistant and susceptible A. aegypti strains. Time-mortality and sublethal effects were evaluated via survival analysis and swimming behavior, respectively. Rhamnolipids showed larvicidal effect at all tested concentrations. Rhamnolipids at 300 mg L-1 killed 100% of both susceptible and resistant larvae within 24 h of exposure and 99% after 30-days stored (pyrethroid-susceptible larvae). Regarding the sublethal effects, the swimming rate was reduced in 50 and 100 mg L-1 of rhamnolipids in grouped (pyrethroid-susceptible) larvae. Rhamnolipids at 50 mg L-1 reduced the distance and speed and increased the number of stops and resting time of individualized pyrethroid-susceptible larvae. The larvicidal effect of the rhamnolipids evaluated demonstrates that these compounds represent an alternative to control A. aegypti.
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Affiliation(s)
- Tatiane de Paula Siqueira
- Laboratório de Biotecnologia e Biodiversidade para o Meio Ambiente, Departamento de Microbiologia, Universidade Federal de Viçosa, Av. P.H. Rolfs s/n, Centro, Viçosa, Minas Gerais Brazil
| | - Wagner Faria Barbosa
- Programa de Pós-Graduação em Entomologia, Departamento de Entomologia, Universidade Federal de Viçosa, Viçosa, Minas Gerais Brazil
| | - Edmo Montes Rodrigues
- Laboratório de Biotecnologia e Biodiversidade para o Meio Ambiente, Departamento de Microbiologia, Universidade Federal de Viçosa, Av. P.H. Rolfs s/n, Centro, Viçosa, Minas Gerais Brazil
- Instituto Federal de Educação, Ciência e Tecnologia do Ceará-IFCE-Campus Camocim, Camocim, Ceará Brazil
| | - Franciane Rosa Miranda
- Programa de Pós-Graduação em Entomologia, Departamento de Entomologia, Universidade Federal de Viçosa, Viçosa, Minas Gerais Brazil
- Laboratório de Biologia Molecular de Insetos, Departamento de Biologia Geral, Universidade Federal de Viçosa, Viçosa, Minas Gerais Brazil
| | - Fernanda de Souza Freitas
- Laboratório de Biotecnologia e Biodiversidade para o Meio Ambiente, Departamento de Microbiologia, Universidade Federal de Viçosa, Av. P.H. Rolfs s/n, Centro, Viçosa, Minas Gerais Brazil
| | - Gustavo Ferreira Martins
- Laboratório de Biologia Molecular de Insetos, Departamento de Biologia Geral, Universidade Federal de Viçosa, Viçosa, Minas Gerais Brazil
| | - Marcos Rogério Tótola
- Laboratório de Biotecnologia e Biodiversidade para o Meio Ambiente, Departamento de Microbiologia, Universidade Federal de Viçosa, Av. P.H. Rolfs s/n, Centro, Viçosa, Minas Gerais Brazil
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França LP, Amaral ACF, Ramos ADS, Ferreira JLP, Maria ACB, Oliveira KMT, Araujo ES, Branches ADS, Silva JN, Silva NG, Barros GDA, Chaves FCM, Tadei WP, Silva JRDA. Piper capitarianum essential oil: a promising insecticidal agent for the management of Aedes aegypti and Aedes albopictus. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2021; 28:9760-9776. [PMID: 33159226 DOI: 10.1007/s11356-020-11148-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Accepted: 10/05/2020] [Indexed: 06/11/2023]
Abstract
Mosquitoes are responsible for serious public health problems worldwide, and as such, Aedes aegypti and Aedes albopictus are important vectors in the transmission of dengue, chikungunya, and Zika in Brazil and other countries of the world. Due to growing resistance to chemical insecticides among populations of vectors, environmentally friendly strategies for vector management are receiving ever more attention. Essential oils (EOs) extracted from plants have activities against insects with multiple mechanisms of action. These mechanisms hinder the development of resistance, and have the advantages of being less toxicity and biodegradable. Thus, the present study aimed to evaluate the chemical composition of the EOs obtained from Piper capitarianum Yunck, as well as evaluating their insecticidal potential against Aedes aegypti and A. albopictus, and their toxicity in relation to Artemia salina. The yields of the EOs extracted from the leaves, stems, and inflorescences of P. capitarianum were 1.2%, 0.9%, and 0.6%, respectively, and their main constituents were trans-caryophyllene (20.0%), α-humulene (10.2%), β-myrcene (10.5%), α-selinene (7.2%), and linalool (6.0%). The EO from the inflorescences was the most active against A. aegypti and A. albopictus, and exhibited the respective larvicidal (LC50 = 87.6 μg/mL and 76.1 μg/mL) and adulticide activities (LC50 = 126.2 μg/mL and 124.5 μg/mL). This EO was also the most active in the inhibition of AChE, since it presented an IC50 value of 14.2 μg/mL. Its larvicidal effect was observed under optical and scanning electron microscopy. Additionally, non-toxic effects against A. salina were observed. Docking modeling of trans-caryophyllene and α-humulene on sterol carrier protein-2 (SCP-2) suggests that both molecules have affinity with the active site of the enzyme, which indicates a possible mechanism of action. Therefore, the essential oil of P. capitarianum may be used in the development of new insecticide targets for the control of A. aegypti and A. albopictus in the Amazonian environment.
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Affiliation(s)
- Leandro P França
- Chromatography Laboratory, Chemistry Department, Federal University of Amazonas, Manaus, AM, Brazil
| | - Ana Claudia F Amaral
- Laboratory of Medicinal Plants and Derivatives, Department of Chemistry of Natural Products, Farmanguinhos, Oswaldo Cruz Foundation, Rio de Janeiro, RJ, Brazil
| | - Aline de S Ramos
- Laboratory of Medicinal Plants and Derivatives, Department of Chemistry of Natural Products, Farmanguinhos, Oswaldo Cruz Foundation, Rio de Janeiro, RJ, Brazil
| | - José Luiz P Ferreira
- Laboratory of Medicinal Plants and Derivatives, Department of Chemistry of Natural Products, Farmanguinhos, Oswaldo Cruz Foundation, Rio de Janeiro, RJ, Brazil
| | - Ana Clara B Maria
- Laboratory of Medicinal Plants and Derivatives, Department of Chemistry of Natural Products, Farmanguinhos, Oswaldo Cruz Foundation, Rio de Janeiro, RJ, Brazil
| | - Kelson Mota T Oliveira
- Laboratory of Theoretical and Computational Chemistry, Chemistry Department, Federal University of Amazonas, Manaus, AM, Brazil
| | - Earle S Araujo
- Laboratory of Theoretical and Computational Chemistry, Chemistry Department, Federal University of Amazonas, Manaus, AM, Brazil
| | - Adjane Dalvana S Branches
- Laboratory of Theoretical and Computational Chemistry, Chemistry Department, Federal University of Amazonas, Manaus, AM, Brazil
| | - Jonathas N Silva
- Laboratory of Theoretical and Computational Chemistry, Chemistry Department, Federal University of Amazonas, Manaus, AM, Brazil
| | - Noam G Silva
- Laboratory of Theoretical and Computational Chemistry, Chemistry Department, Federal University of Amazonas, Manaus, AM, Brazil
| | - Gabriel de A Barros
- Laboratory of Theoretical and Computational Chemistry, Chemistry Department, Federal University of Amazonas, Manaus, AM, Brazil
| | | | - Wanderli P Tadei
- Laboratory of Malaria and Dengue, Institute for Research in the Amazon, Manaus, AM, Brazil
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Acoustic tracheal rupture provides insights into larval mosquito respiration. Sci Rep 2020; 10:2378. [PMID: 32047234 PMCID: PMC7012908 DOI: 10.1038/s41598-020-59321-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Accepted: 01/28/2020] [Indexed: 11/08/2022] Open
Abstract
Acoustic larviciding (AL) occurs by exposing mosquito larvae to acoustic energy that ruptures their dorsal tracheal trunks (DTTs) by the expulsion of gas bubbles into the body. In studying this technique, we serendipitously identified undescribed anatomical and physiological respiratory features. The classical theory of respiration is that the siphon and DTTs play obligate roles in respiration. Our results contradict the accepted theory that culicine larvae respire via atmospheric gas exchange. We identified an undescribed tracheal occlusion (TO) at the posterior extremities the DTTs. The TOs appear necessary for the acoustic rupture of DTTs; this constriction prevents the escape of energized gas from the siphon and allows the tracheal system to be pressurized. With a pressurized isolated tracheal system, metabolic gas exchange directly with the atmosphere is unlikely and could mostly occur through the chitin and setae. Future studies are needed to explore respiration and elucidate the mechanisms of oxygen absorption and carbon dioxide elimination.
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Rumbos CI, Athanassiou CG. Assessment of selected larvicides for the control of Culex pipiens biotype pipiens and Culex pipiens biotype molestus under laboratory and semi-field conditions. PEST MANAGEMENT SCIENCE 2020; 76:3568-3576. [PMID: 32533802 DOI: 10.1002/ps.5847] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2019] [Revised: 01/31/2020] [Accepted: 06/13/2020] [Indexed: 06/11/2023]
Abstract
BACKGROUND The insecticidal efficacy of selected mosquito larvicides [teflubenzuron, S-methoprene, diflubenzuron, temephos, Bacillus thuringiensis var. israelensis (Bti) and polydimethylsiloxane (PDMS)], applied alone or in combination, against two Culex pipiens biotypes, Cx. p. pipiens and Cx. p. molestus, was compared under laboratory and semi-field conditions. Registered larvicides were evaluated at the label dose, whereas those not registered for mosquito control were tested at the label dose per area, i.e. as plant protection products. Teflubenzuron and temephos were also evaluated at half the label dose, alone or in combination with a non-ionic surfactant. Larval mortality and adult emergence were assessed after 1, 3, 5, 7, 9, 11, 16 and 20 days of exposure. RESULTS In all cases, PDMS showed complete (100%) larval control after 3 days of exposure against both biotypes. With temephos, all larvae were dead after 1 day of exposure, even at half the label dose. For teflubenzuron, mortality reached 100% at the end of the bioassays and adult emergence was avoided completely, whereas for diflubenzuron, mortality was close to 100% at the end of the trials. By contrast, in S-methoprene-treated water, control was below the 90% mortality threshold for both biotypes. In semi-field trails, in all treatments with Bti, all larvae of both biotypes were dead after 1 day of exposure. CONCLUSIONS Based on our data, and with the exception of S-methoprene, the larvicides tested remained below the threshold for effective treatment against larvae of Cx. p. pipiens and Cx. p. molestus for the entire duration of the study. Most of the larvicides tested showed high levels of efficacy against Cx. p. pipiens and Cx. p. molestus larvae in laboratory and semi-field bioassays. © 2020 Society of Chemical Industry.
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Affiliation(s)
- Christos I Rumbos
- Laboratory of Entomology and Agricultural Zoology, Department of Agriculture, Crop Production and Rural Environment, University of Thessaly, Volos, Greece
| | - Christos G Athanassiou
- Laboratory of Entomology and Agricultural Zoology, Department of Agriculture, Crop Production and Rural Environment, University of Thessaly, Volos, Greece
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Dawood AFD, Baz MM, Ibrahim MI. Influence of Aquatain™, a monomolecular surface film on surface tension for controlling the filarial vector Culex pipiens (Diptera: Culicidae). Heliyon 2020; 6:e05314. [PMID: 33134587 PMCID: PMC7586106 DOI: 10.1016/j.heliyon.2020.e05314] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Revised: 08/11/2020] [Accepted: 10/16/2020] [Indexed: 12/07/2022] Open
Abstract
Surface tension is a phenomenon in the liquid media and plays an important part in the development and survival of aquatic animals. Influence of Aquatain™ monomolecular film on surface tension was determined against mosquito larvae and pupae at different temperatures (10, 15, 20, 25, 30 and 35 °C) and Aquatain™ doses (0.5, 1.0 and 2.0 ml/m2). In the laboratory, Aquatain™ showed larvicidal and pupicidal effects against the filarial vector Culex pipiens. Higher mortality was observed in late and more weighted instars/stages than young ones as well as in the pupal stage. The pupal mortality reached 76.2%, 86% and 93.3% after 12 h post-treatment at 0.5, 1.0 and 2.0 ml/m2, respectively, and it was completely eliminated (100%) within 24 h compared to 15.1%, 26.9% and 38.2% for 1st larval instar, respectively. Also, results showed at 0.5 ml/m2 with temperature range: 10, 15, 20, 25, 30 and 35 °C, the mortality reached 4.0, 6.7, 10.8, 17.3, 22.7, 29.3% and 32, 44, 54, 72, 84, 97.3% for 1st and 4th larval instar, respectively, where the surface tension (γ) was 65.6, 62.4, 58.0, 57.0, 54.2 and, 49.6 dyn/cm, while the Aquatain™ was more effective on mosquito larvae and pupae at high doses with the temperature range. On the other hand, without Aquatain™ dose, the mortality value ranged between 0.0 - 1.2%, and the surface tension (γ) was 74.5 dyne/cm, which is considered as an accidental death. Aquatain™ was effective against all aquatic phases of mosquitoes, especially against the last and weighted ones. Not only was the efficacy of Aquatain™ increased by increasing the dose, but it also increased with the increased temperature of the environment. This efficiency of Aquatain™ is due to its ability to reduce the surface tension of the water medium, preventing different stages of mosquitoes from reaching the surface for breathing thereby leading to suffocation and death. Therefore, we recommended Aquatain™ in programmes for mosquito control and other aquatic insects as a safe, cost-effective control agent.
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Affiliation(s)
| | - Mohamed M Baz
- Entomology Department, Faculty of Science, Benha University, Qalyubiya 13518, Egypt
| | - Moustafa I Ibrahim
- Physics Department, Faculty of Science, Benha University, Qalyubiya 13518, Egypt
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Abstract
The effective management of mosquito vectors is a timely challenge for medical and veterinary entomology. In this study, we evaluated the acoustic Larvasonic device to control young instars of the mosquito Aedes aegypti in diverse freshwater environments. Under laboratory conditions, we investigated the effect of exposure time and distance from the transducer on the mortality of larvae and pupae of Ae. aegypti. Furthermore, we evaluated the effectiveness of the ultrasound window of the electromagnetic spectrum under different field conditions. Results showed that first and second instar larvae were more sensitive to the frequency range of 18–30 kHz of the Larvasonic device. Ultrasonic waves applied for 180 s at a frequency from 18 to 30 kHz caused 100% larval mortality at a distance of 60 cm from the transducer. No mortality was observed in the non-target copepod Megacyclops formosanus. The exposure to the soundwaves produced by the acoustic larvicidal device over different distances effectively damaged Ae. aegypti through destruction of the larval dorsal tracheal trunk, thorax and abdomen. Overall, results indicated that the Larvasonic device tested can provide an alternative tool to reduce young instar populations of Ae. aegypti, without any effects on non-target aquatic invertebrates like copepods. It turned out to be a useful device for mosquito biocontrol. This technology has a relevant potential to fight the spread of mosquito-borne diseases.
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Taylor DJ, Connelly SJ, Kotov AA. The Intercontinental phylogeography of neustonic daphniids. Sci Rep 2020; 10:1818. [PMID: 32020006 PMCID: PMC7000678 DOI: 10.1038/s41598-020-58743-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Accepted: 01/07/2020] [Indexed: 11/30/2022] Open
Abstract
Organisms that live at the freshwater surface layer (the neuston) occupy a high energy habitat that is threatened by human activities. Daphniids of the genera Scapholeberis and Megafenestra are adapted to the neuston but are poorly studied for biogeography and diversity. Here we assess the global phylogeography of neustonic daphniids. We obtained 402 new multigene sequences from the 12S rRNA, 16S rRNA, and tRNA (val) regions of the mitochondrial genomes of daphniids from 186 global sites. We assessed the intercontinental origins and boundaries of mitochondrial lineages and the relative rates of evolution in neustonic and planktonic daphniids. We identified 17 divergent lineages in the neustonic daphniids that were associated with biogeographic regions. Six of these lineages had intercontinental ranges – four of these were Transberingian. Patagonian populations of Scapholeberis rammneri were monophyletic and nested within a closely related clade of western North American haplotypes, suggesting an introduction from the Western Nearctic to South America. The Eastern Palearctic was more diverse than other regions, containing eight of the major lineages detected in the Scapholeberinae. The Genus Scapholeberis had high levels of divergence compared to non-neustonic daphniids. Neustonic daphniids have more divergent biogeographic lineages than previously appreciated.
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Affiliation(s)
- Derek J Taylor
- Department of Biological Sciences, The State University of New York at Buffalo, Buffalo, NY, 14260, USA.
| | - Sandra J Connelly
- Thomas H. Gosnell School of Life Sciences, Rochester Institute of Technology, Rochester, NY, USA
| | - Alexey A Kotov
- A. N. Severtsov Institute of Ecology and Evolution, Leninsky Prospect 33, 119071, Moscow, Russia
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11
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Nunes RKV, Martins UN, Brito TB, Nepel A, Costa EV, Barison A, Santos RLC, Cavalcanti SCH. Evaluation of (-)-borneol derivatives against the Zika vector, Aedes aegypti and a non-target species, Artemia sp. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2018; 25:31165-31174. [PMID: 30187415 DOI: 10.1007/s11356-018-2809-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Accepted: 07/19/2018] [Indexed: 06/08/2023]
Abstract
Zika, dengue, and chikungunya are vector-borne diseases of pronounced concern transmitted by the mosquito Aedes aegypti Linn. (Diptera: Culicidae). The most important method to avoid outbreaks is to control mosquito spreading by the employment of insecticides and larvicides. Failure to control mosquito dispersal is mostly accounted to Ae. aegypti resistance to currently available larvicides and insecticides, encouraging the development of novel pesticides. In addition, the excessive use of larvicides poses serious threats to human health and the environment. Evaluation of natural products as larvicides in an attempt to overcome this situation is often found in the literature because products originated from nature are considered less toxic to non-target species and more eco-friendly. (-)-Borneol is a bicyclic monoterpene present in essential oils with moderate larvicidal activity. On account of these facts, it was of our interest to synthesize (-)-borneol ester derivatives aiming to study its structure-activity relationships against Ae. aegypti larvae. With the goal to estimate toxicity to a non-target species, evaluation of the lethal concentration 50% (LC50) on Artemia sp. (Artemiidae) and calculation of selectivity towards Ae. aegypti were carried out. The most potent derivative, (-)-Bornyl chloroacetate, exhibited the highest suitability index, demonstrating lower environmental toxicity than other borneol ester derivatives. A parabolic relationship between (-)-borneol esters larvicidal activity and partition coefficient (Log P) was achieved and a correlation equation obtained, validating the importance of lipophilicity to the larvicidal activity of these compounds.
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Affiliation(s)
- Rafaela K V Nunes
- Medicinal Chemistry Laboratory, Pharmacy Department, Federal University of Sergipe, São Cristóvão, SE, 49100-000, Brazil
| | - Ulisses N Martins
- Medicinal Chemistry Laboratory, Pharmacy Department, Federal University of Sergipe, São Cristóvão, SE, 49100-000, Brazil
| | - Thaysnara B Brito
- Medicinal Chemistry Laboratory, Pharmacy Department, Federal University of Sergipe, São Cristóvão, SE, 49100-000, Brazil
| | - Angelita Nepel
- Nuclear Magnetic Resonance Laboratory, Chemistry Department, Federal University of Paraná, PO Box 19081, Curitiba, PR, 81531-990, Brazil
| | - Emmanoel V Costa
- Chemistry Department, Institute of Applied Sciences, Federal University of Amazonas, Manaus, Brazil
| | - Andersson Barison
- Nuclear Magnetic Resonance Laboratory, Chemistry Department, Federal University of Paraná, PO Box 19081, Curitiba, PR, 81531-990, Brazil
| | - Roseli L C Santos
- Parasitology Laboratory, Morphology Department, Federal University of Sergipe, São Cristóvão, SE, 49100-000, Brazil
| | - Sócrates C H Cavalcanti
- Medicinal Chemistry Laboratory, Pharmacy Department, Federal University of Sergipe, São Cristóvão, SE, 49100-000, Brazil.
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