Cellular mechanisms of acid secretion in the posterior midgut of the larval mosquito (Aedes aegypti)

SUMMARYThe larval mosquito midgut exhibits one of the highest pH values known in a biological system. While the pH inside the posterior midgut and gastric caeca ranges between 7.0 and 8.0, the pH inside the anterior midgut is close to 11.0. Alkalization is likely to involve bicarbonate/carbonate ions. These ions are produced in vivo by the enzymatic action of carbonic anhydrase. The purpose of this study was to investigate the role of this enzyme in the alkalization mechanism, to establish its presence and localization in the midgut of larval Aedes aegypti and to clone and characterize its cDNA. Here, we report the physiological demonstration of the involvement of carbonic anhydrase in midgut alkalization. Histochemistry and in situ hybridization showed that the enzyme appears to be localized throughout the midgut, although preferentially in the gastric caeca and posterior regions with specific cellular heterogeneity. Furthermore, we report the cloning and localization of the first carbonic anhydrase from mosquito larval midgut. A cDNA clone from Aedes aegypti larval midgut revealed sequence homology to α-carbonic anhydrases from vertebrates. Bioinformatics indicates the presence of at least six carbonic anhydrases or closely related genes in the genome of another dipteran, the fruit fly Drosophila melanogaster. Molecular analyses suggest that the larval mosquito may also possess multiple forms.

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Confocal Analysis of the Distribution and Persistence of Sindbis Virus (TaV-GFP) Infection in Midguts of Aedes aegypti Mosquitoes

Microscopy and Microanalysis ◽

10.1017/s1431927620001270 ◽

2020 ◽

Vol 26 (2) ◽

pp. 267-274

Author(s):

Jason J. Saredy ◽

Florence Y. Chim ◽

Zoë L. Lyski ◽

Yani P. Ahearn ◽

Doria F. Bowers

Keyword(s):

Aedes Aegypti ◽

Sindbis Virus ◽

Fluorescent Protein ◽

Blood Feeding ◽

Target Tissue ◽

Secondary Target ◽

Posterior Midgut ◽

Infected Cells ◽

Green Fluorescent ◽

Global Threat

AbstractBiological transmission of arthropod-borne viruses (arboviruses) to vertebrate hosts by hematophagous insects poses a global threat because such arboviruses can result in a range of serious public health infectious diseases. Sindbis virus (SINV), the prototype Alphavirus, was used to track infections in the posterior midgut (PMG) of Aedes aegypti adult mosquitoes. Females were fed viremic blood containing a virus reporter, SINV [Thosea asigna virus-green fluorescent protein (TaV-GFP)], that leaves a fluorescent signal in infected cells. We assessed whole-mount PMGs to identify primary foci, secondary target tissues, distribution, and virus persistence. Following a viremic blood meal, PMGs were dissected and analyzed at various days of post blood-feeding. We report that virus foci indicated by GFP in midgut epithelial cells resulted in a 9.8% PMG infection and a 10.8% dissemination from these infected guts. The number of virus foci ranged from 1 to 3 per individual PMG and was more prevalent in the PMG-middle > PMG-frontal > PMG-caudal regions. SINV TaV-GFP was first observed in the PMG (primary target tissue) at 3 days post blood-feeding, was sequestered in circumscribed foci, replicated in PMG peristaltic muscles (secondary target tissue) following dissemination, and GFP was observed to persist in PMGs for 30 days postinfection.

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Cellular mechanisms and inhibitors of gastric acid secretion

Drugs of Today ◽

10.1358/dot.1999.35.10.561693 ◽

1999 ◽

Vol 35 (10) ◽

pp. 743 ◽

Cited By ~ 5

Author(s):

M.J.-M. Lewin

Keyword(s):

Acid Secretion ◽

Gastric Acid Secretion ◽

Gastric Acid ◽

Cellular Mechanisms

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Intracellular Interactions Between Arboviruses and Wolbachia in Aedes aegypti

Frontiers in Cellular and Infection Microbiology ◽

10.3389/fcimb.2021.690087 ◽

2021 ◽

Vol 11 ◽

Author(s):

Jerica Isabel L. Reyes ◽

Yasutsugu Suzuki ◽

Thaddeus Carvajal ◽

Maria Nilda M. Muñoz ◽

Kozo Watanabe

Keyword(s):

Aedes Aegypti ◽

Vector Control ◽

Host Species ◽

Control Strategies ◽

Cytoskeletal Proteins ◽

Cellular Interactions ◽

Cellular Mechanisms ◽

Cellular Regeneration ◽

Release Program ◽

Human Infections

Aedes aegypti is inherently susceptible to arboviruses. The geographical expansion of this vector host species has led to the persistence of Dengue, Zika, and Chikungunya human infections. These viruses take advantage of the mosquito’s cell to create an environment conducive for their growth. Arboviral infection triggers transcriptomic and protein dysregulation in Ae. aegypti and in effect, host antiviral mechanisms are compromised. Currently, there are no existing vaccines able to protect human hosts from these infections and thus, vector control strategies such as Wolbachia mass release program is regarded as a viable option. Considerable evidence demonstrates how the presence of Wolbachia interferes with arboviruses by decreasing host cytoskeletal proteins and lipids essential for arboviral infection. Also, Wolbachia strengthens host immunity, cellular regeneration and causes the expression of microRNAs which could potentially be involved in virus inhibition. However, variation in the magnitude of Wolbachia’s pathogen blocking effect that is not due to the endosymbiont’s density has been recently reported. Furthermore, the cellular mechanisms involved in this phenotype differs depending on Wolbachia strain and host species. This prompts the need to explore the cellular interactions between Ae. aegypti-arboviruses-Wolbachia and how different Wolbachia strains overall affect the mosquito’s cell. Understanding what happens at the cellular and molecular level will provide evidence on the sustainability of Wolbachia vector control.

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Intracellular Interactions between Arboviruses and Wolbachia in Aedes aegypti

10.20944/preprints202104.0151.v1 ◽

2021 ◽

Author(s):

Jerica Isabel Reyes ◽

Yasutsugu Suzuki ◽

Thaddeus Carvajal ◽

Maria Nilda Muñoz ◽

Kozo Watanabe

Keyword(s):

Aedes Aegypti ◽

Vector Control ◽

Control Strategies ◽

Host Responses ◽

Cellular Interactions ◽

Viral Inhibition ◽

Cellular Mechanisms ◽

Release Program ◽

Human Infections ◽

Cellular Components

Aedes aegypti is inherently susceptible to arboviruses. The geographical expansion of this vector host species has led to the persistence of Dengue, Zika and Chikungunya human infections. These viruses take advantage of the mosquito’s cell to create an environment conducive for their growth. Arboviral infection triggers transcriptomic and protein dysregulation in Ae. aegypti and in effect, host antiviral mechanisms are compromised. Currently, there are no existing vaccines able to protect human hosts from these infections and thus, vector control strategies such as Wolbachia mass release program is regarded as a viable option. Considerable evidence demonstrates how the presence of Wolbachia interferes with arboviruses by decreasing cellular components vital for the pathogen and strengthening antiviral host responses. However, variation in the magnitude of Wolbachia’s viral inhibition that is neither due to strain nor density has been observed. Furthermore, the cellular mechanisms involved in the endosymbiont’s pathogen-blocking differs among hosts. This prompts the need to explore the cellular interactions between Ae. aegypti-arboviruses-Wolbachia and how these interactions overall affect the mosquito’s cell. Understanding what happens at the cellular and molecular level will provide evidence on the sustainability of Wolbachia vector control.

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