scholarly journals Prevalence and molecular characterization of Wolbachia in field-collected Aedes albopictus, Anopheles sinensis, Armigeres subalbatus, Culex pipiens and Cx. tritaeniorhynchus in China

2021 ◽  
Vol 15 (10) ◽  
pp. e0009911
Author(s):  
Yi Yang ◽  
Yifan He ◽  
Guoding Zhu ◽  
Jilei Zhang ◽  
Zaicheng Gong ◽  
...  
Keyword(s):  
Aedes Albopictus ◽  
Culex Pipiens ◽  
Large Scale ◽  
Natural Infection ◽  
Natural Populations ◽  
Surface Protein ◽  
Anopheles Sinensis ◽  
Infection Level ◽  
Armigeres Subalbatus

Wolbachia are maternally transmitted intracellular bacteria that can naturally and artificially infect arthropods and nematodes. Recently, they were applied to control the spread of mosquito-borne pathogens by causing cytoplasmic incompatibility (CI) between germ cells of females and males. The ability of Wolbachia to induce CI is based on the prevalence and polymorphism of Wolbachia in natural populations of mosquitoes. In this study, we screened the natural infection level and diversity of Wolbachia in field-collected mosquitoes from 25 provinces of China based on partial sequence of Wolbachia surface protein (wsp) gene and multilocus sequence typing (MLST). Among the samples, 2489 mosquitoes were captured from 24 provinces between July and September, 2014 and the remaining 1025 mosquitoes were collected month-by-month in Yangzhou, Jiangsu province between September 2013 and August 2014. Our results showed that the presence of Wolbachia was observed in mosquitoes of Aedes albopictus (97.1%, 331/341), Armigeres subalbatus (95.8%, 481/502), Culex pipiens (87.0%, 1525/1752), Cx. tritaeniorhynchus (17.1%, 14/82), but not Anopheles sinensis (n = 88). Phylogenetic analysis indicated that high polymorphism of wsp and MLST loci was observed in Ae. albopictus mosquitoes, while no or low polymorphisms were in Ar. subalbatus and Cx. pipiens mosquitoes. A total of 12 unique mutations of deduced amino acid were identified in the wsp sequences obtained in this study, including four mutations in Wolbachia supergroup A and eight mutations in supergroup B. This study revealed the prevalence and polymorphism of Wolbachia in mosquitoes in large-scale regions of China and will provide some useful information when performing Wolbachia-based mosquito biocontrol strategies in China.

scholarly journals Naturally Occurence Of Wolbachia Spp. Infection In Populations Of Aedes Albopictus In The City of Valencia, Spain

2020 ◽  
Author(s):  
Antonio Marcilla ◽  
MARÍA TRELIS ◽  
FERMÍN QUERO DE LERA ◽  
RUBÉN BUENO-MARÍ
Keyword(s):  
Aedes Albopictus ◽  
Urban Areas ◽  
Social Impact ◽  
Natural Populations ◽  
Surface Protein ◽  
Mediterranean Area ◽  
Relevant Information ◽  
The City ◽  
Potential Use

Abstract Background: The presence of Aedes albopictus was first reported in Valencia (Eastern Spain) in 2015, having a high sanitary and social impact. Innovative tools for its control include the use of the endosymbiotic bacterium Wolbachia pipientis, which suppress Ae. albopictus populations. The release of mosquito males infected with the bacteria has proven effective as a control strategy in similar urban areas in Rome, Italy. Before this strategy could be implemented in Valencia, it is crucial to know whether natural local populations of Ae. albopictus are infected with Wolbachia pipientis and if so, identifying the bacteria strains/supergroups. Methods: Eggs were collected from water basins from the 19 districts of the city of Valencia between May and October 2019. A total of 50 Ae. albopictus reared mosquito adults were processed and analyzed for the presence Wolbachia by selected markers for 16S rDNA and surface protein (wsp) genes, under optimized PCR conditions and sequenced.Results: Our study reveal that 94,7% of the samples carried the endosymbiont, with no differences among sexes. In relation to the Wolbachia strains, both wAlbA and wAlbB strains were identified in the mosquitoes analyzed, with some samples carrying mixed infections. Conclusions: These data provide the first characterization of endosymbionts present in natural populations of Ae. albopictus in the Mediterranean area of Spain, and offers relevant information to evaluate the potential use of Wolbachia strains in order to achieve mosquito populations suppression through massive releases of males artificially infected.

scholarly journals Identification and molecular characterization of Wolbachia strains in natural populations of Aedes albopictus in China

2020 ◽  
Vol 13 (1) ◽  
Author(s):  
Yaping Hu ◽  
Zhiyong Xi ◽  
Xiaobo Liu ◽  
Jun Wang ◽  
Yuhong Guo ◽  
...  
Keyword(s):  
Aedes Albopictus ◽  
Dengue Infection ◽  
Natural Populations ◽  
Pcr Amplification ◽  
Surface Protein ◽  
Multiple Infection ◽  
Rrna Gene ◽  
Dengue Outbreaks ◽  
Surface Protein Gene

Abstract Background Aedes albopictus is naturally infected with Wolbachia spp., maternally transmitted bacteria that influence the reproduction of hosts. However, little is known regarding the prevalence of infection, multiple infection status, and the relationship between Wolbachia density and dengue outbreaks in different regions. Here, we assessed Wolbachia infection in natural populations of Ae. albopictus in China and compared Wolbachia density between regions with similar climates, without dengue and with either imported or local dengue. Results To explore the prevalence of Wolbachia infection, Wolbachia DNA was detected in mosquito samples via PCR amplification of the 16S rRNA gene and the surface protein gene wsp. We found that 93.36% of Ae. albopictus in China were positive for Wolbachia. After sequencing gatB, coxA, hcpA, ftsZ, fbpA and wsp genes of Wolbachia strains, we identified a new sequence type (ST) of wAlbB (464/465). Phylogenetic analysis indicated that wAlbA and wAlbB strains formed a cluster with strains from other mosquitoes in a wsp-based maximum likelihood (ML) tree. However, in a ML tree based on multilocus sequence typing (MLST), wAlbB STs (464/465) did not form a cluster with Wolbachia strains from other mosquitoes. To better understand the association between Wolbachia spp. and dengue infection, the prevalence of Wolbachia in Ae. albopictus from different regions (containing local dengue cases, imported dengue cases and no dengue cases) was determined. We found that the prevalence of Wolbachia was lower in regions with only imported dengue cases. Conclusions The natural prevalence of Wolbachia infections in China was much lower than in other countries or regions. The phylogenetic relationships among Wolbachia spp. isolated from field-collected Ae. albopictus reflected the presence of dominant and stable strains. However, wAlbB (464/465) and Wolbachia strains did not form a clade with Wolbachia strains from other mosquitoes. Moreover, lower densities of Wolbachia in regions with only imported dengue cases suggest a relationship between fluctuations in Wolbachia density in field-collected Ae. albopictus and the potential for dengue invasion into these regions.

scholarly journals Functional characterization of SARS-CoV-2 vaccine elicited antibodies in immunologically naive and pre-immune humans

2021 ◽  
Author(s):  
David Forgacs ◽  
Hyesun Jang ◽  
Rodrigo B Abreu ◽  
Hannah B Hanley ◽  
Jasper L Gattiker ◽  
...  
Keyword(s):  
Large Scale ◽  
Natural Infection ◽  
Functional Characterization ◽  
Antibody Binding ◽  
Viral Neutralization ◽  
Slowing Down ◽  
Igg Binding ◽  
Binding Antibody ◽  
Antibody Levels

As the COVID-19 pandemic continues, the authorization of vaccines for emergency use has been crucial in slowing down the rate of infection and transmission of the SARS-CoV-2 virus that causes COVID-19. In order to investigate the longitudinal serological responses to SARS-CoV-2 natural infection and vaccination, a large-scale, multi-year serosurveillance program entitled SPARTA (SARS SeroPrevalence and Respiratory Tract Assessment) was initiated at 4 locations in the U.S. The serological assay presented here measuring IgG binding to the SARS-CoV-2 receptor binding domain (RBD) detected antibodies elicited by SARS-CoV-2 infection or vaccination with a 95.5% sensitivity and a 95.9% specificity. We used this assay to screen more than 3100 participants and selected 20 previously infected pre-immune and 32 immunologically naive participants to analyze their antibody binding to RBD and viral neutralization (VN) responses following vaccination with two doses of either the Pfizer-BioNTech BNT162b2 or the Moderna mRNA-1273 vaccine. Vaccination not only elicited a more robust immune reaction than natural infection, but the level of neutralizing and anti-RBD antibody binding after vaccination is also significantly higher in pre-immune participants compared to immunologically naive participants (p<0.0033). Furthermore, the administration of the second vaccination did not further increase the neutralizing or binding antibody levels in pre-immune participants (p=0.69). However, ~46% of the immunologically naive participants required both vaccinations to seroconvert.

Some applications of electron beam microanalysis techniques in VLSI process evaluation

1983 ◽  
Vol 41 ◽  
pp. 160-161
Author(s):  
Simon Thomas
Keyword(s):  
Integrated Circuits ◽  
Process Evaluation ◽  
Large Scale ◽  
Technology Development ◽  
Analytical Techniques ◽  
Successful Implementation ◽  
Analysis Of Failures ◽  
Characterization Of Materials ◽  
Circuits Vlsi

Trends in the technology development of very large scale integrated circuits (VLSI) have been in the direction of higher density of components with smaller dimensions. The scaling down of device dimensions has been not only laterally but also in depth. Such efforts in miniaturization bring with them new developments in materials and processing. Successful implementation of these efforts is, to a large extent, dependent on the proper understanding of the material properties, process technologies and reliability issues, through adequate analytical studies. The analytical instrumentation technology has, fortunately, kept pace with the basic requirements of devices with lateral dimensions in the micron/ submicron range and depths of the order of nonometers. Often, newer analytical techniques have emerged or the more conventional techniques have been adapted to meet the more stringent requirements. As such, a variety of analytical techniques are available today to aid an analyst in the efforts of VLSI process evaluation. Generally such analytical efforts are divided into the characterization of materials, evaluation of processing steps and the analysis of failures.

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