Selection of Aedes aegypti (Diptera: Culicidae) strains that are susceptible or refractory to Dengue-2 virus

2013 ◽  
Vol 145 (3) ◽  
pp. 273-282 ◽  
Author(s):  
Paola A. Caicedo ◽  
Olga L. Barón ◽  
Mauricio Pérez ◽  
Neal Alexander ◽  
Carl Lowenberger ◽  
...  
Keyword(s):  
Aedes Aegypti ◽  
Molecular Mechanisms ◽  
Selection Process ◽  
Control Strategies ◽  
Vector Competence ◽  
Survival Rates ◽  
Kaplan Meier ◽  
Genetic And Environmental Factors ◽  
Seven Generations ◽  
Selection Of

AbstractThe vector competence (VC) of Aedes aegypti (Linnaeus) (Diptera: Culicidae) varies geographically and is affected by both genetic and environmental factors. Understanding the molecular mechanisms that influence VC may help develop novel control strategies. The selection of susceptible and refractory strains is the first step in this process. We collected immature A. aegypti in the field and established strains that were susceptible and refractory to Dengue-2 virus by isofamily selection through several generations. Infection was detected by immunofluorescence of head or midgut tissues to determine infection barriers and the % of VC by tissue. We selected three strains: Susceptible (Cali-S) (96.4% susceptible at F19), Refractory with a midgut escape barrier (Cali-MEB) (44.1% refractory at F15), and Refractory with a midgut infection barrier (Cali-MIB) (40% refractory at F16). The effects of the infection were measured using Kaplan–Meier survival rates over the first seven generations. All selected strains showed a similar decrease in survival and in the number of eggs laid/female through the seven generations, suggesting that changes were a result of the selection process rather than the virus infection. The results of this study suggest that VC is associated with multiple genes, which have additive effects on susceptibility.

scholarly journals Molecular Aspects of Cancer Research Endometrium – The Prospect of Personalized Treatment

2021 ◽  
pp. 346-356
Author(s):  
Movchan Oksana
Keyword(s):  
Endometrial Cancer ◽  
Molecular Mechanisms ◽  
Selection Process ◽  
Meta Analysis ◽  
Treatment Options ◽  
Survival Rates ◽  
Molecular Processes ◽  
Pubmed Database ◽  
Wide Range ◽  
Molecular Aspects

Aims: Endometrial cancer is the most common gynaecological cancer, and there is a growing interest in identifying the molecular pathways involved and developing molecular-targeted treatment to prevent it. Present study was aimed to give an overview of the molecular processes involved in endometrial cancer development and treatment options. Methods: We conducted a comprehensive systematic literature review and meta-analysis. For that purpose, PubMed database was searched for related studies till June 2021 and a through selection process was adopted to select the eligible studies. Results: Endometrial malignancies are complicated molecularly, and their focused therapy has a wide range of outcomes, with median progressive survival rates ranging from 2.3 to 18 months. Conclusions: The effective treatment and therapy need a detailed understanding of the molecular mechanisms underlying the creation and progression of endometrial cancer, as well as the development of innovative targeted therapeutic agents.

scholarly journals Vector competence of Aedes aegypti and screening for differentially expressed microRNAs exposed to Zika virus

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Chunling Zhu ◽  
Yuting Jiang ◽  
Qianghui Zhang ◽  
Jian Gao ◽  
Chaojie Li ◽  
...  
Keyword(s):  
Salivary Gland ◽  
Aedes Aegypti ◽  
Mirna Expression ◽  
Zika Virus ◽  
Molecular Mechanisms ◽  
Transmission Rate ◽  
Vector Competence ◽  
Expression Profiles ◽  
Future Research ◽  
Mirna Expression Profiles

Abstract Background Zika virus (ZIKV) is transmitted to humans primarily by Aedes aegypti. Previous studies on Ae. aegypti from Jiegao (JG) and Mengding (MD) in Yunnan province, China have shown that these mosquitoes are able to transmit ZIKV to their offspring through vertical transmission, indicating that these two Ae. aegypti strains pose a potential risk for ZIKV transmission. However, the vector competence of these two Ae. aegypti strains to ZIKV has not been evaluated and the molecular mechanisms influencing vector competence are still unclear. Methods Aedes aegypti mosquitoes from JG and MD were orally infected with ZIKV, and the infection rate (IR), dissemination rate (DR), transmission rate (TR) and transmission efficiency (TE) of these two mosquito strains were explored to evaluate their vector competence to ZIKV. On 2, 4 and 6 days post-infection (dpi), the small RNA profiles between ZIKV-infected and non-infected Ae. aegypti midgut and salivary gland tissues were compared to gain insights into the molecular interactions between ZIKV and Ae. aegypti. Results There were no significant differences in the IR, DR, TR and TE between the two Ae. aegypti strains (P > 0.05). However, ZIKV RNA appeared 2 days earlier in saliva of the JG strain, which indicated a higher competence of the JG strain to transmit ZIKV. Significant differences in the microRNA (miRNA) expression profiles between ZIKV-infected and non-infected Ae. aegypti were found in the 2-dpi libraries of both the midgut and salivary gland tissues from the two strains. In addition, 27 and 74 miRNAs (|log2 fold change| > 2) were selected from the miRNA expression profiles of ZIKV-infected and non-infected midgut and salivary gland tissues from the JG and MD strains, respectively. Conclusions Our results provide novel insights into the ZIKV–mosquito interactions and build a foundation for future research on how miRNAs regulate the vector competence of mosquitoes to this arbovirus. Graphical abstract

Brazilian Aedes aegypti as a competent vector for multiple complex arboviral coinfections

2021 ◽  
Author(s):  
Nilton Barnabé Rodrigues ◽  
Raquel Soares Maia Godoy ◽  
Alessandra Silva Orfano ◽  
Barbara Aparecida Chaves ◽  
Thais Bonifácio Campolina ◽  
...  
Keyword(s):  
Aedes Aegypti ◽  
Infection Rate ◽  
Yellow Fever ◽  
Vector Competence ◽  
Survival Rates ◽  
Multiple Infection ◽  
Single Infection ◽  
Multiple Infections ◽  
Viral Abundance ◽  
Disseminated Infection

Abstract Background Aedes aegypti is a highly competent vector in the transmission of arboviruses, such as chikungunya, dengue, Zika and yellow fever, and causes single and coinfections in the populations of tropical countries. Methods The infection rate, viral abundance, vector competence, disseminated infection and survival rate were recorded after single and multiple infections of the vector with 15 combinations of chikungunya, dengue, Zika and yellow fever arboviruses. Results Infection rates were 100% in all single and multiple infection experiments, except in one triple coinfection that presented a rate of 50%. The vector competence and disseminated infection rate varied from 100% (in single and quadruple infections) to 40% (in dual and triple infections). The dual and triple coinfections altered the vector competence and/or viral abundance of at least one of the arboviruses. The highest viral abundances were detected for a single infection with chikungunya. The viral abundances in quadruple infections were similar when compared to each respective single infection. A decrease in survival rates was observed in a few combinations. Conclusions Ae. aegypti was able to host all single and multiple arboviral coinfections. The interference of the chikungunya virus suggests that distinct arbovirus families may have a significant role in complex coinfections.

scholarly journals Genetics of Mosquito Vector Competence

2000 ◽  
Vol 64 (1) ◽  
pp. 115-137 ◽  
Author(s):  
Brenda T. Beerntsen ◽  
Anthony A. James ◽  
Bruce M. Christensen
Keyword(s):  
Sindbis Virus ◽  
Molecular Mechanisms ◽  
Germ Line ◽  
Control Strategies ◽  
Vector Competence ◽  
Parasite Development ◽  
Mosquito Vector ◽  
Susceptible Population ◽  
Pathogen Destruction

SUMMARY Mosquito-borne diseases are responsible for significant human morbidity and mortality throughout the world. Efforts to control mosquito-borne diseases have been impeded, in part, by the development of drug-resistant parasites, insecticide-resistant mosquitoes, and environmental concerns over the application of insecticides. Therefore, there is a need to develop novel disease control strategies that can complement or replace existing control methods. One such strategy is to generate pathogen-resistant mosquitoes from those that are susceptible. To this end, efforts have focused on isolating and characterizing genes that influence mosquito vector competence. It has been known for over 70 years that there is a genetic basis for the susceptibility of mosquitoes to parasites, but until the advent of powerful molecular biological tools and protocols, it was difficult to assess the interactions of pathogens with their host tissues within the mosquito at a molecular level. Moreover, it has been only recently that the molecular mechanisms responsible for pathogen destruction, such as melanotic encapsulation and immune peptide production, have been investigated. The molecular characterization of genes that influence vector competence is becoming routine, and with the development of the Sindbis virus transducing system, potential antipathogen genes now can be introduced into the mosquito and their effect on parasite development can be assessed in vivo. With the recent successes in the field of mosquito germ line transformation, it seems likely that the generation of a pathogen-resistant mosquito population from a susceptible population soon will become a reality.

scholarly journals Treatment of Metastatic Uveal Melanoma: Systematic Review

Cancers ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2557
Author(s):  
Cristina Rodriguez-Vidal ◽  
Daniel Fernandez-Diaz ◽  
Beatriz Fernandez-Marta ◽  
Nerea Lago-Baameiro ◽  
María Pardo ◽  
...  
Keyword(s):  
Systematic Review ◽  
Uveal Melanoma ◽  
Selection Process ◽  
Liver Perfusion ◽  
Current Treatment ◽  
Treatment Modalities ◽  
Kaplan Meier ◽  
Unit Of Measurement ◽  
Strict Selection ◽  
Selection Of

Introduction: More than 50% of patients with uveal melanoma end up developing metastases. Currently, there is no standard first-line treatment that facilitates proper management of the metastatic disease. Methods: A systematic review of the last 40 years in PubMed with an exhaustive and strict selection of studies was conducted, in which the unit of measurement was overall survival (OS) expressed in Kaplan–Meier curves or numerically. Results: After the selection process, 110 articles were included. Regional therapies, such as intra-arterial liver chemotherapy (OS: 2, 9–22 months), isolated liver perfusion (OS: 9, 6–27, 4 months), or selective internal radiation therapy (OS: 18 months in monotherapy and 26 months in combination with other therapies) showed some superiority when compared to systemic therapies, such as chemotherapy (OS: 4, 6–17 months), immunotherapy (OS: 5–19, 1 month), immunosuppression (OS: 11 months), or targeted therapy (OS: 6–12 months), without being significant. Conclusions: The results of this review suggest that there are no important differences in OS when comparing the different current treatment modalities. Most of the differences found seem to be explained by the heterogenicity of the different studies and the presence of biases in their design, rather than actual extensions of patient survival.

scholarly journals Recent outbreaks of chikungunya virus (CHIKV) in Africa and Asia are driven by a variant carrying mutations associated with increased fitness for Aedes aegypti

2018 ◽  
Author(s):  
Irina Maljkovic Berry ◽  
Fredrick Eyase ◽  
Simon Pollett ◽  
Samson Limbaso Konongoi ◽  
Katherine Figueroa ◽  
...  
Keyword(s):  
Aedes Aegypti ◽  
Chikungunya Virus ◽  
Control Strategies ◽  
Vector Competence ◽  
Virus Transmission ◽  
New Delhi ◽  
African Countries ◽  
Global Spread ◽  
Large Outbreak ◽  
The Impact

AbstractBackgroundIn 2016, a chikungunya virus (CHIKV) outbreak was reported in Mandera, Kenya. This was the first major CHIKV outbreak in the country since the global re-emergence of this virus, which arose as an initial outbreak in Kenya in 2004. Therefore, we collected samples and sequenced viral genomes from the 2016 Mandera outbreak.Methodology/Principal FindingsAll Kenyan genomes contained two mutations, E1:K211E and E2:V264A, recently reported to have an association with increased infectivity, dissemination and transmission in the Aedes aegypti (Ae. aegypti) vector. Phylogeographic inference of temporal and spatial virus relationships using Bayesian approaches showed that this Ae. aegypti adapted strain emerged within the East, Central, and South African (ECSA) lineage of CHIKV between 2005 and 2008, most probably in India. It was also in India where the first large outbreak caused by this strain appeared, in New Delhi, 2010. More importantly, our results also showed that this strain is no longer contained to India, and that it has more recently caused several major outbreaks of CHIKV, including the 2016 outbreaks in India, Pakistan and Kenya, and the 2017 outbreak in Bangladesh. In addition to its capability to cause large outbreaks in different regions of the world, this CHIKV strain has the capacity to replace less adapted wild type strains in Ae. aegypti-rich regions. Indeed, all the latest full CHIKV genomes of the ECSA Indian Ocean Lineage (IOL), from the regions of high Ae. aegypti prevalence, carry these two mutations, including samples collected in Japan, Australia, and China.Conclusions/SignificanceOur results point to the importance of continued genomic-based surveillance of this strain’s global spread, and they prompt urgent vector competence studies in Asian and African countries, in order to assess the level of vector receptiveness, virus transmission, and the impact this might have on this strain’s ability to cause major outbreaks.Author summaryChikungunya virus (CHIKV) causes a debilitating infection with high fever, intense muscle and bone pain, rash, nausea, vomiting and headaches, and persistent and/or recurrent joint pains for months or years after contracting the virus. CHIKV is spread by two mosquito vectors, Aedes albopictus and Aedes aegypti, with increased presence around the globe. In this study, we report global spread of a CHIKV strain that carries two mutations that have been suggested to increase this virus’ ability to infect the Aedes aegypti mosquito, as well as to increase CHIKV’s ability to be transmitted by this vector. We show that this strain appeared sometime between 2005 and 2008, most probably in India, and has now spread to Africa, Asia, and Australia. We show that this strain is capable of driving large outbreaks of CHIKV in the human population, causing recent major outbreaks in Kenya, Pakistan, India and Bangladesh. Thus, our results stress the importance of monitoring this strain’s global spread, as well as the need of improved vector control strategies in the areas of Aedes aegypti prevalence.

scholarly journals Peningkatan dan aktivitas enzim asetilkolinesterase pada nyamuk Aedes aegypti yang diseleksi dengan malation

2017 ◽  
Vol 2 (2) ◽  
pp. 24
Author(s):  
Dwi Jayanti Gunandini ◽  
P. B. Wicaksana
Keyword(s):  
Aedes Aegypti ◽  
Selection Process ◽  
Activity Level ◽  
Process Time ◽  
Reference Groups ◽  
L 96 ◽  
Low Levels ◽  
Selection Of

The Elevated and Activity of Acetilcholinesterase Enzyme on Aedes aegypti Selected by Malathion. The aim of this research was to study the effect of selection by malathion on the activity level  Acetilcholinesterase enzyme on Aedes aegypti mosquitoes. Selection of Aedes aegypti larval by mean of malathion have been conducted for 20 generations. During the selection process time has been increased of concentration applied and exposure. For generation 0-5 (F0-F5), a concentration of 25 µl/l (24 ppm) was used to expose the larvae to malathion for five minutes. In generation 6-10 (F6-F10) the concentration has increased to 50 µl/l (48 ppm); in F11-F15 the concentration used was 100 µl/l (96 ppm) whereas in F16-F20 200µl/l (192 ppm) was used. Mosquito generations that would be regarded as representative and reference groups were F0, F5, F10, F15 and F20. The LC50 of F0, F5, F10, F15 and F20 was 0,025; 0,032; 0,042; 0,062 and 0,071 ppm respectively. Increases LT50 values was also observed in Aedes aegypti selected by malathion. The LT50 of F0, F5, F10, F15 and F20 generations was 7,9; 11,3; 18; 30,6 and 33,1 minutes respectively. The low levels of malathion resistance could be conferred by the elevated of α-esterase. The values of the α-esterase in F0, F5, F10, F15 and F20 were 0,155; 0,174; 0,203; 0,209 and 0,215 µmol/min/mg protein respectively. The acetilcholinesterase activities were also raised in F0, F5, F10, F15 and F20, the value of acetilcholinesterase activities were 20,35; 20,26; 23,14; 23,18 and 24,9%.

scholarly journals Wolbachia pipientis occurs in Aedes aegypti populations in New Mexico and Florida, USA

2018 ◽  
Author(s):  
Aditi Kulkarni ◽  
Wanqin Yu ◽  
Jinjin Jiang ◽  
Concepcion Sanchez ◽  
Ajit K. Karna ◽  
...  
Keyword(s):  
New Mexico ◽  
Aedes Aegypti ◽  
Control Strategies ◽  
Vector Competence ◽  
Virus Transmission ◽  
Lamp Assay ◽  
Harris County ◽  
Pcr Assay ◽  
Wolbachia Pipientis ◽  
Pcr Products

ABSTRACTThe mosquitoes Aedes aegypti (L.) and Ae. albopictus Skuse are the major vectors of dengue, Zika, yellow fever and chikungunya viruses worldwide. Wolbachia, an endosymbiotic bacterium present in many insects, is being utilized in novel vector control strategies to manipulate mosquito life history and vector competence to curb virus transmission. Earlier studies have found that Wolbachia is commonly detected in Ae. albopictus but rarely detected in Ae. aegypti. In this study, we used a two-step PCR assay to detect Wolbachia in wild-collected samples of Ae. aegypti. The PCR products were sequenced to validate amplicons and identify Wolbachia strains. A loop-mediated isothermal amplification (LAMP) assay was developed and used for detecting Wolbachia in selected mosquito specimens as well. We found Wolbachia in 85/148 (57.4%) wild Ae. aegypti specimens from various cities in New Mexico and in 2/46 (4.3%) from St. Augustine, Florida. We did not detect Wolbachia in 94 samples of Ae. aegypti from Deer Park, Harris County, Texas. Wolbachia detected in Ae. aegypti from both New Mexico and Florida was the wAlbB strain of Wolbachia pipientis. A Wolbachia positive colony of Ae. aegypti was established from pupae collected in Las Cruces, New Mexico in 2018. The infected females of this strain transmitted Wolbachia to their progeny when crossed with males of Rockefeller strain of Ae. aegypti, which does not carry Wolbachia. In contrast, none of the progeny of progeny of Las Cruces males mated to Rockefeller females were infected with Wolbachia.

scholarly journals Aedes aegypti Infection With Trypanosomatid Strigomonas culicis Alters Midgut Redox Metabolism and Reduces Mosquito Reproductive Fitness

2021 ◽  
Vol 11 ◽  
Author(s):  
Ana Cristina S. Bombaça ◽  
Ana Caroline P. Gandara ◽  
Vitor Ennes-Vidal ◽  
Vanessa Bottino-Rojas ◽  
Felipe A. Dias ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Aedes Aegypti ◽  
Antioxidant System ◽  
Control Strategies ◽  
Vector Competence ◽  
Health Impact ◽  
Reproductive Fitness ◽  
Insect Immunity ◽  
Transcriptional Modulation ◽  
Immune Related Genes

Aedes aegypti mosquitoes transmit arboviruses of important global health impact, and their intestinal microbiota can influence vector competence by stimulating the innate immune system. Midgut epithelial cells also produce toxic reactive oxygen species (ROS) by dual oxidases (DUOXs) that are essential players in insect immunity. Strigomonas culicis is a monoxenous trypanosomatid that naturally inhabits mosquitoes; it hosts an endosymbiotic bacterium that completes essential biosynthetic pathways of the parasite and influences its oxidative metabolism. Our group previously showed that S. culicis hydrogen peroxide (H2O2)-resistant (WTR) strain is more infectious to A. aegypti mosquitoes than the wild-type (WT) strain. Here, we investigated the influence of both strains on the midgut oxidative environment and the effect of infection on mosquito fitness and immunity. WT stimulated the production of superoxide by mitochondrial metabolism of midgut epithelial cells after 4 days post-infection, while WTR exacerbated H2O2 production mediated by increased DUOX activity and impairment of antioxidant system. The infection with both strains also disrupted the fecundity and fertility of the females, with a greater impact on reproductive fitness of WTR-infected mosquitoes. The presence of these parasites induced specific transcriptional modulation of immune-related genes, such as attacin and defensin A during WTR infection (11.8- and 6.4-fold, respectively) and defensin C in WT infection (7.1-fold). Thus, we propose that A. aegypti oxidative response starts in early infection time and does not affect the survival of the H2O2-resistant strain, which has a more efficient antioxidant system. Our data provide new biological aspects of A. aegypti–S. culicis relationship that can be used later in alternative vector control strategies.

scholarly journals Engineered resistance to Zika virus in transgenic Aedes aegypti expressing a polycistronic cluster of synthetic small RNAs

2019 ◽  
Vol 116 (9) ◽  
pp. 3656-3661 ◽  
Author(s):  
Anna Buchman ◽  
Stephanie Gamez ◽  
Ming Li ◽  
Igor Antoshechkin ◽  
Hsing-Han Li ◽  
...  
Keyword(s):  
Aedes Aegypti ◽  
Zika Virus ◽  
Small Rnas ◽  
Sterile Insect Technique ◽  
Control Strategies ◽  
Vector Competence ◽  
Gene Drive ◽  
Artificial Infection ◽  
Transmission Rates ◽  
Arboviral Transmission

Recent Zika virus (ZIKV) outbreaks have highlighted the necessity for development of novel vector control strategies to combat arboviral transmission, including genetic versions of the sterile insect technique, artificial infection with Wolbachia to reduce population size and/or vectoring competency, and gene drive-based methods. Here, we describe the development of mosquitoes synthetically engineered to impede vector competence to ZIKV. We demonstrate that a polycistronic cluster of engineered synthetic small RNAs targeting ZIKV is expressed and fully processed in Aedes aegypti, ensuring the formation of mature synthetic small RNAs in the midgut where ZIKV resides in the early stages of infection. Critically, we demonstrate that engineered Ae. aegypti mosquitoes harboring the anti-ZIKV transgene have significantly reduced viral infection, dissemination, and transmission rates of ZIKV. Taken together, these compelling results provide a promising path forward for development of effective genetic-based ZIKV control strategies, which could potentially be extended to curtail other arboviruses.

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