Michael A Riehle

Michael A Riehle
The University of Arizona | UA · Department of Entomology

Doctor of Philosophy
Exploring mosquito physiology and vector/parasite interactions.

About

126
Publications
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Publications

Publications (126)
Article
Full-text available
Given that older Aedes aegypti (L.) mosquitoes typically pose the greatest risk of pathogen transmission, the capacity to age grade wild Ae. aegypti mosquito populations would be a valuable tool in monitoring the potential risk of arboviral transmission. Here, we compared the effectiveness of near-infrared spectroscopy (NIRS) to age grade field-col...
Article
Full-text available
Rhipicephalus sanguineus s.l. (Latreille, 1806), the brown dog tick, is the most widely distributed tick species in the world. The two dominant lineages, a temperate group and a tropical group, are recognized as important disease vectors for both dogs and humans. The temperate and tropical lineages overlap in range in some regions of the world, inc...
Article
In vertebrates and invertebrates, the insulin/insulin-like growth factor 1 (IGF1) signaling (IIS) cascade is highly conserved and plays a vital role in many different physiological processes. Among the many tissues that respond to IIS in mosquitoes, the fat body has a central role in metabolism, lifespan, reproduction, and innate immunity. We previ...
Article
Full-text available
Malaria parasites require pantothenate from both human and mosquito hosts to synthesize coenzyme A (CoA). Specifically, mosquito-stage parasites cannot synthesize pantothenate de novo or take up preformed CoA from the mosquito host, making it essential for the parasite to obtain pantothenate from mosquito stores. This makes pantothenate utilization...
Article
Full-text available
Mitochondrial integrity and homeostasis in the midgut are key factors controlling mosquito fitness and anti-pathogen resistance. Targeting genes that regulate mitochondrial dynamics represents a potential strategy for limiting mosquito-borne diseases. AMP-activated protein kinase (AMPK) is a key cellular energy sensor found in nearly all eukaryotic...
Article
Full-text available
Across diverse organisms, various physiologies are profoundly regulated by mitochondrial function, which is defined by mitochondrial fusion, biogenesis, oxidative phosphorylation (OXPHOS), and mitophagy. Based on our data and significant published studies from Caenorhabditis elegans , Drosophila melanogaster and mammals, we propose that midgut mito...
Article
Vertical transmission, or pathogen transfer from female to offspring, can facilitate the persistence of emerging arboviruses, such as Zika virus (ZIKV), through periods of low horizontal transmission or adverse environmental conditions. We aimed at determining the rate of vertical transmission for ZIKV in its principal vector, Aedes aegypti, and th...
Preprint
Full-text available
Background: The Aedes aegypti mosquito is a vector of several viruses including dengue, chikungunya, zika, and yellow fever. Vector surveillance and control are the primary methods used for the control and prevention of disease transmission, however, there is an overreliance on measures of population abundance in surveillance programs as a trigger...
Preprint
Background: The Aedes aegypti mosquito is a vector of several viruses including dengue, chikungunya, zika, and yellow fever. Vector surveillance and control are the primary methods used for the control and prevention of disease transmission, however, these activities rely on measures of population abundance in surveillance programs as a trigger for...
Article
The Aedes aegypti mosquito is the primary vector of dengue, yellow fever, chikungunya, and Zika viruses. Infection with the dengue virus alone occurs in an estimated 400 million people each year. Likelihood of infection with a virus transmitted by Ae. aegypti is most commonly attributed to abundance of the mosquito. However, the Arizona-Sonora dese...
Article
Full-text available
Insulin-like peptides (ILPs) and the insulin/insulin-like growth factor 1 signaling (IIS) cascade regulate numerous physiological functions, including lifespan, reproduction, immunity, and metabolism, in diverse eukaryotes. We previously demonstrated that in female Anopheles stephensi and Aedes aegypti mosquitoes, activation of the IIS cascade in t...
Article
Full-text available
Malaria is a global health concern caused by infection with Plasmodium parasites. With rising insecticide and drug resistance, there is a critical need to develop novel control strategies, including strategies to block parasite sporogony in key mosquito vector species. MAPK signaling pathways regulated by extracellular signal-regulated kinases (ERK...
Data
The M3 MKP4 transgenic A. stephensi expressed significantly more MKP4-HA protein than the M4 line. Immunoblots were performed on the midguts of M3 and M4 mosquitoes prior to blood feeding (0 h) and 24 hours after blood feeding (24 h). While M3 line mosquitoes had more MKP4-HA protein expressed both before and after blood feeding, the increased expr...
Data
Identification of the MKP4 genomic insertion site in transgenic A. stephensi. Inverse PCR was used to identify the 5’ and 3’ sequences surrounding the MKP4 construct in the A. stephensi M3 line. A schematic of inverse PCR product sequence is shown. Transgenic genomic DNA was cut with Mbol, self-ligated and used as a PCR template with piggybac (pBac...
Data
The conserved ATP binding site in human and A. stephensi JNK isoforms. Human (Hs) JNK1, JNK2, and JNK3 and A. stephensi (As) JNK1 and JNK3 show significant overall conservation among the residues that compose the ATP binding site (black triangles). The cysteine residue with which JNK-IN-8 forms a covalent bond (open circle) is conserved in A. steph...
Data
JNK SMIs at levels tested in vivo do not directly affect P. falciparum asexual growth in vitro. Synchronized, asexual stage P. falciparum parasites were treated with increasing concentrations of JNK SMIs and growth was evaluated at 48 and 96 h post treatment. Relative growth was normalized to parasites treated with diluent control (set at 1, dashed...
Data
MKP4 midgut expression suppresses p38 phosphorylation following an infectious bloodmeal, but has no impact on ERK phosphorylation. Non-transgenic (NTG) and MKP4 transgenic A. stephensi (M3) were assayed for p38 (A) and ERK (B) phosphorylation prior to bloodfeeding (NBF) and after being provided with a P. falciparum infected bloodmeal (Pf). ERK and...
Data
Levels of midgut lactate, pyruvate and the ratio of active-to-total pyruvate dehydrogenase complex activity in JNK SMI-treated and control A. stephensi. Samples were evaluated as described utilizing enzymatic assays [73]. Data were analyzed by ANOVA followed by Bonferroni’s post-hoc analysis. (TIFF)
Preprint
Full-text available
Vertical transmission, or pathogen transfer from mother to offspring, can facilitate persistence of emerging arboviruses, such as Zika virus (ZIKV), in mosquito populations. Understanding vertical transmission and the different environmental and temporal conditions that affect it is important to assess whether new outbreaks could occur without rein...
Chapter
The blood meal provides more than simple nutrition to the hematophagous arthropod. It provides a wealth of signaling information through a variety of components present in the blood meal. These signaling factors in turn activate highly conserved signaling cascades at the blood meal-interface between the blood and gut, allowing the information to be...
Article
Dengue virus, primarily transmitted by the Aedes aegypti (L.) mosquito, has rapidly expanded in geographic extent over the past several decades. In some areas, however, dengue fever has not emerged despite established Ae. aegypti populations. The reasons for this are unclear and have sometimes been attributed to socio-economic differences. In 2013...
Article
Full-text available
Insulin-like peptides (ILPs) play important roles in growth and metabolic homeostasis, but have also emerged as key regulators of stress responses and immunity in a variety of vertebrates and invertebrates. Further, a growing literature suggests that insulin signaling-dependent metabolic provisioning can influence host responses to infection and af...
Article
Full-text available
In 2008 we published the first set of guidelines for standardizing research in autophagy. Since then, research on this topic has continued to accelerate, and many new scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Accordingly, it is important to update these guidelines for monitoring au...
Article
Full-text available
The insulin-like peptides (ILPs) and their respective signaling and regulatory pathways are highly conserved across phyla. In invertebrates, ILPs regulate diverse physiological processes, including metabolism, reproduction, behavior, and immunity. We previously reported that blood feeding alone induced minimal changes in ILP expression in Anopheles...
Article
Resveratrol, a plant polyphenol present in grape skins, has been theorized to account for the "French Paradox" by explaining how red wine may decrease the health risks associated with unhealthy diets. Resveratrol has been reported to extend lifespan in several different species. Other studies, however, have failed to find a resveratrol-induced life...
Article
Full-text available
Variation in vectorial capacity for human malaria among Anopheles mosquito species is determined by many factors, including behavior, immunity, and life history. To investigate the genomic basis of vectorial capacity and explore new avenues for vector control, we sequenced the genomes of 16 anopheline mosquito species from diverse locations spannin...
Article
Full-text available
Akt signaling regulates diverse physiologies in a wide range of organisms. We examine the impact of increased Akt signaling in the fat body of 2 mosquito species, the Asian malaria mosquito Anopheles stephensi and the yellow fever mosquito Aedes aegypti. Overexpression of a myristoylated and active form of A. stephensi and Ae. aegypti Akt in the fa...
Conference Paper
The aim of this research is to develop our understanding of how wing size, blood feeding success, and longevity are related in Aedes aegypti populations. Wing size is reflective of the environmental conditions during larval development and is likely to influence vectorial capacity during adulthood. Those that are involved in the surveillance and co...
Article
Full-text available
Background: Anopheles stephensi is the key vector of malaria throughout the Indian subcontinent and Middle East and an emerging model for molecular and genetic studies of mosquito-parasite interactions. The type form of the species is responsible for the majority of urban malaria transmission across its range. Results: Here, we report the genome se...
Article
Full-text available
Insulin and insulin-like growth factor signaling (IIS) regulates cell death, repair, autophagy, and renewal in response to stress, damage, and pathogen challenge. Therefore, IIS is fundamental to lifespan and disease resistance. Previously, we showed that insulin-like growth factor 1 (IGF1) within a physiologically relevant range (0.013-0.13 µM) in...
Article
Full-text available
Tsetse flies are the sole vectors of human African trypanosomiasis throughout sub-Saharan Africa. Both sexes of adult tsetse feed exclusively on blood and contribute to disease transmission. Notable differences between tsetse and other disease vectors include obligate microbial symbioses, viviparous reproduction, and lactation. Here, we describe th...
Article
Full-text available
Tsetse flies are the sole vectors of human African trypanosomiasis throughout sub-Saharan Africa. Both sexes of adult tsetse feed exclusively on blood and contribute to disease transmission. Notable differences between tsetse and other disease vectors include obligate microbial symbioses, viviparous reproduction, and lactation. Here, we describe th...
Article
Full-text available
Tsetse flies are the sole vectors of human African trypanosomiasis throughout sub-Saharan Africa. Both sexes of adult tsetse feed exclusively on blood and contribute to disease transmission. Notable differences between tsetse and other disease vectors include obligate microbial symbioses, viviparous reproduction, and lactation. Here, we describe th...
Chapter
This book, which is divided into four parts, describes the advances in insect transgenesis. Part 1 deals with germline transformation technology while part 2 focuses on the application of transgenic insects, including plant insect pests and insect vectors (such as mosquitoes). Part 3 shows alternative transgenic approaches to modifying insect pheno...
Article
This chapter discusses the insulin-like peptides: structure, signaling, and function. Insulin-like peptides (ILPs) are paragons for the conservation of hormone structure and function among invertebrates and higher animals. They are encoded by multiple, distinct genes within each species and, upon secretion, serve as hormones, neurotransmitters, and...
Article
The insulin/insulin-like growth factor signaling (IIS) cascade is highly conserved and regulates diverse physiological processes such as metabolism, lifespan, reproduction and immunity. Transgenic overexpression of Akt, a critical regulator of IIS, was previously shown to shorten mosquito lifespan and increase resistance to the human malaria parasi...
Data
Amino acid alignments of insect and human ATPase beta subunit (ATPB) revealed high sequence homology for cross-species detection. Alignment of representative ATPB orthologs was performed by retrieving primary sequences from the SwissProt database and aligning them with CLUSTALW. The position of the critical tyrosine for nitration and aromatic amino...
Data
Over-expression of myrAkt was associated with the appearance of stalled autophagosomes. (A) Greater detail of a stalled autophagosome (SA) showing the composition of the SA as stacked sheets of membranous material. Image is from posterior midgut cell of 18 d old HM myrAkt An. stephensi taken at 15,000×. (B) Example of invagination of the midgut bru...
Data
HPLC chromatogram of a mixture of nucleotide standards. Standards containing 1 mM of each metabolite (ATP, ADP, AMP, NAD, NADH, and hypoxanthine) were followed at 265 nm. Retention times for these standards are shown in the table. (TIF)
Data
Supporting information. Supplementary materials and methods. (DOCX)
Data
L-NAME and D-NAME treatment did not affect growth of asexual-stage P. falciparum. Replicate cultures of P. falciparum NF54 were incubated for 48 h and 96 h with 0.74 mM or 3.7 mM L-NAME or D-NAME. Relative growth was compared to the water control, which is set at 100%. Data from three independent experiments were analyzed by ANOVA and by Dunnett's...
Article
Full-text available
The overexpression of activated, myristoylated Akt in the midgut of female transgenic results in resistance to infection with the human malaria parasite but also decreased lifespan. In the present study, the understanding of mitochondria-dependent midgut homeostasis has been expanded to explain this apparent paradox in an insect of major medical im...
Conference Paper
Reactive oxygen species (ROS) are oxygen-based free radicals normally produced by electrons leaked from the electron transport chain during aerobic metabolism. Because ROS are highly reactive and can damage cell membranes, DNA, and proteins, cells have a tightly-regulated response mechanism to relieve states of elevated ROS concentrations (oxidativ...
Article
Full-text available
Aedes aegypti, the primary vector of dengue virus, is well established throughout urban areas of the Southwestern US, including Tucson, AZ. Local transmission of the dengue virus, however, has not been reported in this area. Although many factors influence the distribution of the dengue virus, we hypothesize that one contributing factor is that the...
Data
Average SCP-1 gene expression per age group. The average SCP-1 gene expression and standard error of single mosquitoes used in the aging model is presented here by age group, untransformed (n = 154). (TIF)
Data
Ae. aegypti orthologues of age associated genes. The five genes (AGAP009551, AGAP011615, AGAP002827, AGAP005501, and AGAP009790) adopted from Wang, 2010 were transformed to Ae. aegypti orthologues with the use of the NCBI Homologene database. The primer sequence and efficiency is provided. (TIF)
Data
Expression profiles of seven putative age associated genes. Three to nine replicates of pooled mosquito samples from various time points (1, 3, 5, 10, 15, 20, or 35 days post emergence) were tested for expression profiles of seven previously reported age associated genes. For AGA011615 (S1D) a significant increase in transcript expression was obser...
Article
Full-text available
We showed previously that ingested human insulin activates the insulin/IGF-1 signaling pathway in Anopheles stephensi and increases the susceptibility of these mosquitoes to Plasmodium falciparum. In other organisms, insulin can alter immune responsiveness through regulation of NF-κB transcription factors, critical elements for innate immunity that...
Article
Insulin-like peptides (ILPs) regulate a multitude of biological processes, including metabolism and immunity to infection, and share similar structural motifs across widely divergent taxa. Insulin/insulin-like growth factor signaling (IIS) pathway elements are similarly conserved. We have shown that IIS regulates reproduction, innate immunity, and...
Article
Full-text available
Adipokinetic hormones are peptide hormones that mobilize lipids and/or carbohydrates for flight in adult insects and activate glycogen Phosphorylase in larvae during starvation and during molt. We previously examined the functional roles of adipokinetic hormone in Manduca sexta L. (Lepidoptera: Sphingidae). Here we report the cloning of the full-le...
Chapter
This chapter discusses the insulin-like peptides: structure, signaling, and function. Insulin-like peptides (ILPs) are paragons for the conservation of hormone structure and function among invertebrates and higher animals. They are encoded by multiple, distinct genes within each species and, upon secretion, serve as hormones, neurotransmitters, and...
Conference Paper
The insulin/insulin growth factor 1 signaling (IIS) cascade is a key regulator of lifespan, reproduction and immunity in numerous organisms, including mosquitoes. To assess the roles of IIS in the mosquitos midgut we genetically engineered an active form of the IIS molecule Akt into Anopheles stephensi mosquitoes. Expression was controlled by the m...
Conference Paper
Mosquito reproduction is regulated by a complex series of hormonal cues. In the ovaries and fat body the insulin/IGF1 signaling (IIS) cascade regulates steroidogenesis and vitellogenesis respectively. Phosphotase and tensin homolog (PTEN) is a direct antagonist of IIS. Using RNAi, knockdown of AaegPTEN or its splice variant AaegPTEN6 resulted in a...
Conference Paper
Dengue is a worldwide threat that could potentially infect millions of people annually. The primary mosquito vector, Aedes aegypti, is well established throughout urban areas of the southwestern US, yet intriguingly the disease is not present. Although many factors may influence dengues distribution, we hypothesize that the lifespan of female Ae. a...
Article
Full-text available
Malaria (Plasmodium spp.) kills nearly one million people annually and this number will likely increase as drug and insecticide resistance reduces the effectiveness of current control strategies. The most important human malaria parasite, Plasmodium falciparum, undergoes a complex developmental cycle in the mosquito that takes approximately two wee...
Article
Malaria (Plasmodium spp.) kills nearly one million people annually and this number will likely increase as drug and insecticide resistance reduces the effectiveness of current control strategies. The most important human malaria parasite, Plasmodium falciparum, undergoes a complex developmental cycle in the mosquito that takes approximately two wee...
Data
Supporting information text. (0.03 MB DOC)
Data
Gene sequence of inverse PCR fragment. A. A schematic of the inverse PCR product sequence. Transgenic genomic DNA was cut with MboI and was self-ligated to form circularized DNA which was used as a template for PCR with pBac-specific primers. As expected, the amplified product (97 bp) from the putative insertion site was flanked with known pBac seq...
Data
Bloodmeal ingestion and digestion are not affected in myr-AsteAKT-HA transgenics. A and B. Transgenic myr-AsteAKT-HA females ingested the same amount of blood as non-transgenic siblings. Average blood intake was calculated as a difference between an average weight of engorged females in the given weight group before and after bloodfeeding. The p-va...
Data
Transcript expression profile of the transgene during mosquito development. Transcript expression at various developmental stages of transgenic mosquitoes (2nd instar larvae, early and late 4th instar larvae, newly eclosed pupae and late (24 h) pupae, and adult males and females). The experiment was replicated four times with separate cohorts of mo...
Article
Full-text available
Mark-capture dispersal studies were conducted to investigate the feasibility of marking the southwestern desert subterranean termite, Heterotermes aureus (Snyder) with rabbit immunoglobulin G (IgG). In turn, short-range dispersal patterns of H. aureus were measured across a 20-m diameter desert landscape at three distinct field locations. Each loca...