scholarly journals Avaliação dos efeitos de biossurfactantes produzidos por Bacillus subtilis LBBMA 4914 e Pseudomonas aeruginosa LBBMA 4951E e surfactantes sintéticos sobre larvas de Culex quinquefaciatus

2016 ◽  
Vol 7 (2) ◽  
pp. 101-110
Author(s):  
Adriano Guimaraes Parreira ◽  
Stenio Nunes Alves ◽  
Marcos Rogerio Totola

Mosquitos da família Culicidae estão presentes em todo o território nacional podendo agir como vetores de doenças diversas, a exemplo da filariose. transmitida por Culex quinquefasciatus. A evidência de resistência aos inseticidas tradicionais tem estimulado o desenvolvimento de pesquisas com novos compostos com potencial ação larvicida. No presente trabalho foram avaliados os efeitos de agentes tensoativos biológicos, os biosurfactantes ramnolipideos produzidos por Pseudomonas aeruginosa LBBMA 4951e lipopetídeos produzidos por Bacillus subtilis LBBMA 4914, além dos sintéticos SDS - Dodecil Sulfato de Sódio, Twen 80 e Triton X, sobre larvas de 3 e 4 instar de C. quinquefasciatus. Os resultados obtidos mostraram-se bastantes promissores indicando grande potencial de ação bioinseticida por parte dos biossurfactantes avaliados, destacando-se a surfactina com ação larvicida sobre 75% do total de espécimes de C. quinquefascitus expostos àquele tensoativo ao longo de 96h. Em relação aos surfactantes sintéticos, observou-se resultado mais pronunciado para Triton X 100, seguido de Tween 80 e SDS, com valores de CL50 de 1,32x10-4M, 2,52x10-4M e 2,84x10-4M, respectivamente. Com isso, a partir deste trabalho abrem-se novas perspectivas para o uso daqueles tensoativos no controle da proliferação de C. quinquefascitus, atuando como bioinseticidas ou aditivos aos já utilizados, assim como para novos testes envolvendo a avaliação de seu efeito sobre outras espécies de Culicidae, a exemplo de Aedes aegypti.

2018 ◽  
Vol 22 (02) ◽  
pp. 82-89
Author(s):  
Friedrich von Rheinbaben ◽  
Oliver Riebe ◽  
Johanna Köhnlein ◽  
Sebastian Werner

ZusammenfassungZentrales Bauteil des Genius® 90 Therapie Systems ist der sogenannte Genius-Tank, dem die frische Dialyseflüssigkeit entnommen und in den die verbrauchte Lösung nach der Dialyse zurückgeführt wird. Daher kommt der sicheren Aufbereitung des Systems eine besondere Bedeutung zu. Hierfür wird ein Aufbereitungsverfahren unter Verwendung von UV-Licht in Kombination mit einem chemischen Desinfektionsmittel angewendet. Ziel der hier beschriebenen Untersuchung war es, die Wirkungsbreite und Wirkungstiefe dieses Aufbereitungsverfahrens unter praxisnahen Phase-3-Bedingungen zu ermitteln. Dazu wurde das Gerät mit Mikroorganismen und Viren künstlich kontaminiert und die Wirkung der einzelnen Verfahrensschritte ermittelt. Im Gegensatz zu der üblichen Vorgehensweise praxisnaher Untersuchungen machen Aufbereitungsverfahren medizinischer Geräte unter Phase-3-Kriterien meist eine neuartige Arbeitsweise erforderlich – im Falle der hier vorgestellten Untersuchung sogar die Konstruktion eines speziellen Geräts zur Platzierung von Keimträgen im Genius-Tank. Im Ergebnis konnte gezeigt werden, dass bereits UV-Licht allein sowie in Kombination mit einem chemischen Desinfektionsmittel unter praxisnahen Bedingungen eine sichere Wirksamkeit gegen Bakterien (Pseudomonas aeruginosa) und bakterielle Sporen (Bacillus subtilis), Schimmelpilze (Aspergillus brasiliensis) und Viren (Murines Parvovirus) besitzt.


2019 ◽  
Vol 9 (02) ◽  
Author(s):  
Hussein A Kadhum ◽  
Thualfakar H Hasan2

The study involved the selection of two isolates from Bacillus subtilis to investigate their inhibitory activity against some bacterial pathogens. B sub-bacteria were found to have a broad spectrum against test bacteria such as Staphylococcus aureus and Pseudomonas aeruginosa. They were about 23-30 mm and less against Klebsiella sp. The sensitivity of some antibodies was tested on the test samples. The results showed that the inhibitory ability of bacterial growth in the test samples using B. subtilis extract was more effective than the antibiotics used.


Insects ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 129
Author(s):  
Matthew W. Hopken ◽  
Limarie J. Reyes-Torres ◽  
Nicole Scavo ◽  
Antoinette J. Piaggio ◽  
Zaid Abdo ◽  
...  

Urban ecosystems are a patchwork of habitats that host a broad diversity of animal species. Insects comprise a large portion of urban biodiversity which includes many pest species, including those that transmit pathogens. Mosquitoes (Diptera: Culicidae) inhabit urban environments and rely on sympatric vertebrate species to complete their life cycles, and in this process transmit pathogens to animals and humans. Given that mosquitoes feed upon vertebrates, they can also act as efficient samplers that facilitate detection of vertebrate species that utilize urban ecosystems. In this study, we analyzed DNA extracted from mosquito blood meals collected temporally in multiple neighborhoods of the San Juan Metropolitan Area, Puerto Rico to evaluate the presence of vertebrate fauna. DNA was collected from 604 individual mosquitoes that represented two common urban species, Culex quinquefasciatus (n = 586) and Aedes aegypti (n = 18). Culex quinquefasciatus fed on 17 avian taxa (81.2% of blood meals), seven mammalian taxa (17.9%), and one reptilian taxon (0.85%). Domestic chickens dominated these blood meals both temporally and spatially, and no statistically significant shift from birds to mammals was detected. Aedes aegypti blood meals were from a less diverse group, with two avian taxa (11.1%) and three mammalian taxa (88.9%) identified. The blood meals we identified provided a snapshot of the vertebrate community in the San Juan Metropolitan Area and have potential implications for vector-borne pathogen transmission.


Insects ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 596
Author(s):  
Anuluck Junkum ◽  
Wanchai Maleewong ◽  
Atiporn Saeung ◽  
Danita Champakaew ◽  
Arpaporn Chansang ◽  
...  

Ligusticum sinense Oliv. cv. is a species of Umbelliferae (Apiaceae), a large plant family in the order Apiales. In this study, L. sinense hexane extract nanoemulsion gel (LHE-NEG) was investigated for mosquito repellency and compared to the standard chemical, N,N-diethyl-3-methylbenzamide (DEET), with the goal of developing a natural alternative to synthetic repellents in protecting against mosquito vectors. The results demonstrated that LHE-NEG afforded remarkable repellency against Aedes aegypti, Anopheles minimus, and Culex quinquefasciatus, with median protection times (MPTs) of 5.5 (4.5–6.0), 11.5 (8.5–12.5), and 11.25 (8.5–12.5) h, respectively, which was comparable to those of DEET-nanoemulsion gel (DEET-NEG: 8.5 (7.0–9.0), 12.0 (10.0–12.5), and 12.5 (10.0–13.5) h, respectively). Evaluation of skin irritation in 30 human volunteers revealed no potential irritant from LHE-NEG. The physical and biological stability of LHE-NEG were determined after being kept under heating/cooling cycle conditions. The stored samples of LHE-NEG exhibited some changes in appearance and differing degrees of repellency between those kept for 3 and 6 heating/cooling cycles, thus providing slightly shorter MPTs of 4.25 (4.0–4.5) and 3.25 (2.5–3.5) h, respectively, when compared to those of 5.0 (4.5–6.0) h in fresh preparation. These findings encourage commercially developed LHE-based products as an alternative to conventional synthetic repellents in preventing mosquito bites and helping to interrupt mosquito-borne disease transmission.


2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Sunil Dhiman ◽  
Kavita Yadav ◽  
B. N. Acharya ◽  
Raj Kumar Ahirwar ◽  
D. Sukumaran

Abstract Background The direct toxicological impact of insecticides on vector mosquitoes has been well emphasized; however, behavioural responses such as excito-repellency and physical avoidance as a result of insecticide exposure have not been much studied. We have demonstrated the excito-repellency and behavioural avoidance in certain vector mosquito species on exposure to a slow-release insecticidal paint (SRIP) formulation in addition to direct toxicity. Methods A SRIP formulation developed by the Defence Research and Development Establishment, Gwalior, contains chlorpyriphos, deltamethrin and pyriproxyfen as active insecticides. Anopheles stephensi, Culex quinquefasciatus and Aedes aegypti mosquitoes were used to study the excito-repellency response of the formulation. The experiments were performed in a specially designed dual-choice exposure and escape chamber made of transparent polymethyl methacrylate. For the experiments, the SRIP formulation was applied undiluted at a rate of 8 m2 per kg on 15 cm2 metallic surfaces. Mosquitoes were introduced into the exposure chamber, and observations of the movement of mosquitoes into the escape chamber through the exit portal were taken at 1-min intervals for up to 30 min. Results The evaluated formulation displayed strong excito-repellency against all three tested vector mosquito species. Results showed that the ET50 (escape time 50%) for Ae. aegypti, An. stephensi and Cx. quinquefasciatus was 20.9 min, 14.5 min and 17.9 min for contact exposure (CE) respectively. Altogether in CE, the escape rates were stronger in An. stephensi mosquitoes at different time intervals compared to Ae. aegypti and Cx. quinquefasciatus mosquitoes. The probit analysis revealed that the determined ET did not deviate from linearity for both non-contact exposure (NCE) and placebo exposure (PE) (χ2 ≤ 7.9; p = 1.0) for Ae. aegypti mosquitoes and for NCE (χ2 = 8.3; p = 1.0) and PE (χ2 = 1.7; p = 1.0) treatments in Cx. quinquefasciatus. Mortality (24 h) was found to be statistically higher (F = 6.4; p = 0.02) in An. stephensi for CE but did not vary for NCE (p ≥ 0.3) and PE (p = 0.6) treatments among the tested mosquito species. Survival probability response suggested that all the three tested species displayed similar survival responses for similar exposures (χ2 ≤ 2.3; p ≥ 0.1). Conclusion The study demonstrates the toxicity and strong behavioural avoidance in known vector mosquito species on exposure to an insecticide-based paint formulation. The combination of insecticides in the present formulation will broaden the overall impact spectrum for protecting users from mosquito bites. The efficacy data generated in the study provide crucial information on the effectiveness of the tested formulation and could be useful in reducing the transmission intensity and disease risk in endemic countries.


2021 ◽  
pp. 108120
Author(s):  
Appadurai Daniel Reegan ◽  
Pachaiyappan Saravana Kumar ◽  
Antony Cruz Asharaja ◽  
Chitra Devi ◽  
Sithi Jameela ◽  
...  

2008 ◽  
Vol 41 (6) ◽  
pp. 658-663 ◽  
Author(s):  
Maria das Graças Vale Barbosa ◽  
Nelson Ferreira Fé ◽  
Alexandre Herculano Ribera Marcião ◽  
Ana Paula Thomé da Silva ◽  
Wuelton Marcelo Monteiro ◽  
...  

A biodiversidade da Região Amazônica inclui diversas espécies de vetores artrópodes em seus diferentes ecótopos, possibilitando o surgimento de doenças como malária, filarioses e arboviroses. De agosto de 2001 a julho de 2002, realizou-se coletas de culicídeos no domicílio, peridomicílio e nas matas da Comunidade São João, área rural de Manaus, Amazonas. Foram capturados 1.240 culicídeos, pertencentes às subfamílias Culicinae (99%) e Anophelinae (1%), somando 50 espécies. O predomínio entre as tribos foi nitidamente de Culicini, com 904 (72,9%) exemplares, destacando-se as espécies Culex usquatus (22,6%) e Culex quinquefasciatus (17,7%). Do total de culicídeos, 1.077 (86,9%) exemplares foram capturados no interior das matas, 101 (8,1%) no peridomicílio e 62 (5%) no intradomicílio. O ecótopo com maior diversidade de espécies foi a mata. Assinalou-se a presença de Anopheles darlingi, Anopheles triannulatus, Aedes aegypti, Haemagogus janthinomys e outros vetores comprovados ou potenciais.


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