Publications by authors named "Emre Aksoy"

30 Publications

  • Page 1 of 1

Juvenile hormone regulation of microRNAs is mediated by E75 in the Dengue vector mosquito .

Proc Natl Acad Sci U S A 2021 Jul;118(29)

Department of Entomology, University of California, Riverside, CA 92521;

MicroRNAs (miRNAs) are small noncoding RNAs that play critical roles in controlling posttranscriptional gene regulation and have a profound effect on mosquito reproduction and metabolism. Juvenile hormone (JH) is critical for achieving reproductive competence in the main vector of human arboviral diseases, We report a JH-mediated mechanism governing miRNA expression. Using a transcription factor screen with multiple primary miRNA (pri-miRNA) promoters, we identified that the Ecdysone-induced protein E75 (E75) isoform (E75-RD) induced miRNA gene promoter activity. E75 binding sites were determined in miRNA promoters by means of cell transfection assay. E75-RD was found to be up-regulated by JH, as shown by the JH application and RNA interference (RNAi) of the JH receptor Methoprene-tolerant (Met). Small RNA sequencing from RNAi of Met and E75 displayed an overlapping miRNA cohort, suggesting E75 to be an intermediate component within the JH hierarchical network controlling miRNAs. Further experiments confirmed that E75-RD positively regulates several miRNAs including miR-2940. Reducing resulted in the arrest of follicle development and number of eggs laid. Performing miRNA target predictions and RT-qPCR from antagomir Ant-2940-3p-treated fat body tissues identified the mRNA target Clumsy ( The molecular interaction between this gene target and miR-2940 was confirmed using an in vitro dual luciferase assay in S2 cells and in Aag2 cell lines. Finally, we performed a phenotypic rescue experiment to demonstrate that miR-2940/Clumsy is responsible for the disruption in egg development. Collectively, these results established the role of JH-mediated E75-RD in regulation of miRNA gene expression during the mosquito reproductive cycle.
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http://dx.doi.org/10.1073/pnas.2102851118DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8307694PMC
July 2021

Combined drought and heat stresses trigger different sets of miRNAs in contrasting potato cultivars.

Funct Integr Genomics 2021 Jul 9;21(3-4):489-502. Epub 2021 Jul 9.

Ayhan Şahenk Faculty of Agricultural Sciences and Technologies, Department of Agricultural Genetic Engineering, Niğde Ömer Halisdemir University, 51240, Niğde, Turkey.

MicroRNAs are small, non-coding RNAs that are responsible for regulation of gene expression during plant growth and development. Although there are many studies on miRNAs in other plants, little work has been done to understand the role of miRNAs in abiotic stress tolerance in potatoes. This study investigates changes in miRNA profiles of two different potato cultivars (tolerant, Unica and susceptible, Russet Burbank) in response to heat, drought and their combination. Transcriptomic studies revealed that miRNA profiles depend on the susceptibility and tolerance of the cultivar and also the stress conditions. Large number of miRNAs were expressed in Unica, whereas Russet Burbank indicated lesser number of changes in miRNA expression. Physiological and transcriptional results clearly supported that Unica cultivar is tolerant to combined drought and heat stress compared to Russet Burbank. Moreover, psRNATarget analysis predicted that major miRNAs identified were targeting genes playing important roles in response to drought and heat stress and their important roles in genetic and post-transcriptional regulation, root development, auxin responses and embryogenesis were also observed. This study focused on eight miRNAs (Novel_8, Novel_9, Novel_105, miR156d-3p, miR160a-5p, miR162a-3p, miR172b-3p and miR398a-5p) and their putative targets where results indicate that they may play a vital role at different post-transcriptional levels against drought and heat stresses. We suggest that miRNA overexpression in plants can lead to increased tolerance against abiotic stresses; furthermore, there should be more emphasis on the studies to investigate the role of miRNAs in combined abiotic stress in plants.
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http://dx.doi.org/10.1007/s10142-021-00793-wDOI Listing
July 2021

Hormone-dependent activation and repression of microRNAs by the ecdysone receptor in the dengue vector mosquito .

Proc Natl Acad Sci U S A 2021 Jun;118(26)

Department of Entomology, University of California, Riverside, CA 92521;

Female mosquitoes transmit numerous devastating human diseases because they require vertebrate blood meal for egg development. MicroRNAs (miRNAs) play critical roles across multiple reproductive processes in female mosquitoes. However, how miRNAs are controlled to coordinate their activity with the demands of mosquito reproduction remains largely unknown. We report that the ecdysone receptor (EcR)-mediated 20-hydroxyecdysone (20E) signaling regulates miRNA expression in female mosquitoes. EcR RNA-interference silencing linked to small RNA-sequencing analysis reveals that EcR not only activates but also represses miRNA expression in the female mosquito fat body, a functional analog of the vertebrate liver. EcR directly represses the expression of clustered and before blood feeding when the 20E titer is low, whereas it activates their expression in response to the increased 20E titer after a blood meal. Furthermore, we find that SMRTER, an insect analog of the vertebrate nuclear receptor corepressors SMRT and N-CoR, interacts with EcR in a 20E-sensitive manner and is required for EcR-mediated repression of miRNA expression in mosquitoes. In addition, we demonstrate that miR-275 and miR-305 directly target and , respectively, to facilitate egg development. This study reveals a mechanism for how miRNAs are controlled by the 20E signaling pathway to coordinate their activity with the demands of mosquito reproduction.
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http://dx.doi.org/10.1073/pnas.2102417118DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8256052PMC
June 2021

Paratransgenic manipulation of a tsetse microRNA alters the physiological homeostasis of the fly's midgut environment.

PLoS Pathog 2021 Jun 9;17(6):e1009475. Epub 2021 Jun 9.

Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, Connecticut, United States of America.

Tsetse flies are vectors of parasitic African trypanosomes, the etiological agents of human and animal African trypanosomoses. Current disease control methods include fly-repelling pesticides, fly trapping, and chemotherapeutic treatment of infected people and animals. Inhibiting tsetse's ability to transmit trypanosomes by strengthening the fly's natural barriers can serve as an alternative approach to reduce disease. The peritrophic matrix (PM) is a chitinous and proteinaceous barrier that lines the insect midgut and serves as a protective barrier that inhibits infection with pathogens. African trypanosomes must cross tsetse's PM in order to establish an infection in the fly, and PM structural integrity negatively correlates with trypanosome infection outcomes. Bloodstream form trypanosomes shed variant surface glycoproteins (VSG) into tsetse's gut lumen early during the infection establishment, and free VSG molecules are internalized by the fly's PM-producing cardia. This process results in a reduction in the expression of a tsetse microRNA (miR275) and a sequential molecular cascade that compromises PM integrity. miRNAs are small non-coding RNAs that are critical in regulating many physiological processes. In the present study, we investigated the role(s) of tsetse miR275 by developing a paratransgenic expression system that employs tsetse's facultative bacterial endosymbiont, Sodalis glossinidius, to express tandem antagomir-275 repeats (or miR275 sponges). This system induces a constitutive, 40% reduction in miR275 transcript abundance in the fly's midgut and results in obstructed blood digestion (gut weights increased by 52%), a significant increase (p-value < 0.0001) in fly survival following infection with an entomopathogenic bacteria, and a 78% increase in trypanosome infection prevalence. RNA sequencing of cardia and midgut tissues from paratransgenic tsetse confirmed that miR275 regulates processes related to the expression of PM-associated proteins and digestive enzymes as well as genes that encode abundant secretory proteins. Our study demonstrates that paratransgenesis can be employed to study microRNA regulated pathways in arthropods that house symbiotic bacteria.
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http://dx.doi.org/10.1371/journal.ppat.1009475DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8216540PMC
June 2021

Evaluation of parents' knowledge, attitudes, and practices regarding self-medication for their children's dental problems during the COVID-19 pandemic: a cross-sectional survey.

BMC Oral Health 2021 03 5;21(1):98. Epub 2021 Mar 5.

Department of Pediatric Dentistry, Faculty of Dentistry, Ondokuz Mayis University, 55270, Samsun, Turkey.

Background: Self-medication refers to taking medicine without consultation with a doctor or dentist, and it is an important health issue, especially during the COVID-19 pandemic. There are no data about parents' SM practices for their children's dental problems during the COVID-19 pandemic. The present study aims to evaluate parents' knowledge, attitudes, and practices regarding self-medication for their children's dental problems during the COVID-19 pandemic in Northern Turkey.

Methods: A cross-sectional survey was carried out in the pediatric dental clinic at Ondokuz Mayis University, Faculty of Dentistry, Department of Pediatric Dentistry, immediately after the COVID-19 lockdown ended. A total of 389 parents who agreed to participate in the study completed the questionnaire from July 1 to October 1. A questionnaire with 18 items was designed to collect information on the parents' knowledge and attitudes regarding when, why, and how to use drugs and on their practices on medicating their children. The collected data were analyzed using descriptive and analytical statistics (chi-square test).

Results: The majority of parents (n = 273; 70.2%) practiced self-medication for their children's dental problems. Self-medication with a previously prescribed medications was usually preferred by parents (n = 179; 62.2%). Analgesics (98%) were the most commonly used medicines by parents in their self-medication for their children's dental problems.

Conclusion: Prevalence of self-medication practices for children's dental problems is high in Turkey during the COVID-19 pandemic. Therefore, new healthcare services, such as teledentistry, may be useful to overcome problems related to the self-medication of children during times when the ability to reach healthcare providers is limited, such as during pandemics.
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http://dx.doi.org/10.1186/s12903-021-01466-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7934979PMC
March 2021

Physiological, Biochemical, and Transcriptional Responses to Single and Combined Abiotic Stress in Stress-Tolerant and Stress-Sensitive Potato Genotypes.

Front Plant Sci 2020 27;11:169. Epub 2020 Feb 27.

Cell and Molecular Sciences, The James Hutton Institute, Dundee, United Kingdom.

Potato production is often constrained by abiotic stresses such as drought and high temperatures which are often present in combination. In the present work, we aimed to identify key mechanisms and processes underlying single and combined abiotic stress tolerance by comparative analysis of tolerant and susceptible cultivars. Physiological data indicated that the cultivars Desiree and Unica were stress tolerant while Agria and Russett Burbank were stress susceptible. Abiotic stress caused a greater reduction of photosynthetic carbon assimilation in the susceptible cultivars which was associated with a lower leaf transpiration rate. Oxidative stress, as estimated by the accumulation of malondialdehyde was not induced by stress treatments in any of the genotypes with the exception of drought stress in Russett Burbank. Stress treatment resulted in increases in ascorbate peroxidase activity in all cultivars except Agria which increased catalase activity in response to stress. Transcript profiling highlighted a decrease in the abundance of transcripts encoding proteins associated with PSII light harvesting complex in stress tolerant cultivars. Furthermore, stress tolerant cultivars accumulated fewer transcripts encoding a type-1 metacaspase implicated in programmed cell death. Stress tolerant cultivars exhibited stronger expression of genes associated with plant growth and development, hormone metabolism and primary and secondary metabolism than stress susceptible cultivars. Metabolite profiling revealed accumulation of proline in all genotypes following drought stress that was partially suppressed in combined heat and drought. On the contrary, the sugar alcohols inositol and mannitol were strongly accumulated under heat and combined heat and drought stress while galactinol was most strongly accumulated under drought. Combined heat and drought also resulted in the accumulation of Valine, isoleucine, and lysine in all genotypes. These data indicate that single and multiple abiotic stress tolerance in potato is associated with a maintenance of CO assimilation and protection of PSII by a reduction of light harvesting capacity. The data further suggests that stress tolerant cultivars suppress cell death and maintain growth and development fine tuning of hormone signaling, and primary and secondary metabolism. This study highlights potential targets for the development of stress tolerant potato cultivars.
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http://dx.doi.org/10.3389/fpls.2020.00169DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7058966PMC
February 2020

Downregulation of imidacloprid resistant genes alters the biological parameters in Colorado potato beetle, Leptinotarsa decemlineata Say (chrysomelidae: Coleoptera).

Chemosphere 2020 Feb 16;240:124857. Epub 2019 Sep 16.

Department of Agricultural Genetic Engineering, Ayhan Şahenk Faculty of Agricultural Sciences and Technologies, Niğde Omer Halisdemir University, Niğde, Turkey. Electronic address:

Colorado potato beetle, Leptinotarsa decemlineata Say (coleoptera: chrysomelidae), is the important pest of potato all over the world. This insect pest is resistant to more than 50 active compounds belonging to various chemical groups. Potential of RNA interference (RNAi) was explored to knock down transcript levels of imidacloprid resistant genes in Colorado potato beetle (CPB) under laboratory conditions. Three important genes belonging to cuticular protein (CP), cytochrome P450 monoxygenases (P450) and glutathione synthetase (GSS) families encoding imidacloprid resistance were targeted. Feeding bio-assays were conducted on various stages of imidacloprid resistant CPB lab population by applying HT115 expressing dsRNA on potato leaflets. Survival rate of insects exposed to CP-dsRNA decreased to 4.23%, 15.32% and 47.35% in 2nd, 3rd and 4th instar larvae respectively. Larval weight and pre-adult duration were also affected due to dsRNAs feeding. Synergism of RNAi with imidacloprid conducted on the 2nd instar larvae, exhibited 100% mortality of larvae when subjected to reduced doses of GSS and CP dsRNAs along with imidacloprid. Utilization of three different dsRNAs against imidacloprid resistant CPB population reveal that dsRNAs targeting CP, P450 and GSS enzymes could be useful tool in management of imidacloprid resistant CPB populations.
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http://dx.doi.org/10.1016/j.chemosphere.2019.124857DOI Listing
February 2020

Transgenic potato lines expressing hairpin RNAi construct of molting-associated EcR gene exhibit enhanced resistance against Colorado potato beetle (Leptinotarsa decemlineata, Say).

Transgenic Res 2019 02 3;28(1):151-164. Epub 2019 Jan 3.

Department of Agricultural Genetic Engineering, Faculty of Agricultural Sciences and Technologies, Nigde Omer Halisdemir University, 51240, Nigde, Turkey.

Most of the commercialized insect resistant transgenic crops express cry gene(s) isolated from Bacillus thuringiensis; however, intensive cultivation of Bt crops over almost two decades has been questioned regarding its sustainability and durability in pest management. The present study focused on silencing of highly specific molting-associated Ecdysone receptor (EcR) gene of Colorado potato beetle (CPB) using RNA interference (RNAi) approach. The partial cDNA of EcR gene of CPB was amplified using specific primers in sense and anti-sense orientations, and cloned in pRNAi-GG vector flanked by an intronic sequence (pdk). Leaf and internodal explants of Agria and Lady Olympia potato cultivars were infected with Agrobacterium strain LBA4404 harboring constructs under the control of CaMV 35S promoter. Standard molecular analysis of primary transformants showed proper integration of T-DNA in plant genome. The transgenic plants of both cultivars were evaluated for their efficacy against first, second and third instar CPB larvae. The leaf biotoxicity assays revealed 15-80% of CPB mortality. A significantly lower fold-change (0.87-4.14×) in larval weight was observed in insects fed on transgenic plants compared to the ones fed on control plants (1.87-6.53×). Furthermore, CPB larvae fed on transgenic plants exhibited reduced EcR transcripts, indicating the functionality of dsRNA EcR in silencing EcR gene expression. This study is an excellent example of the integration of an alternative, effective and reliable method to cope with potato insect pests that incur significant losses to potato production in the world.
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http://dx.doi.org/10.1007/s11248-018-0109-7DOI Listing
February 2019

Symbiotic microbes affect the expression of male reproductive genes in Glossina m. morsitans.

BMC Microbiol 2018 11 23;18(Suppl 1):169. Epub 2018 Nov 23.

Department of Biology and Biotechnology, University of Pavia, 27100, Pavia, Italy.

Background: Tsetse flies (Diptera, Glossinidae) display unique reproductive biology traits. Females reproduce through adenotrophic viviparity, nourishing the growing larva into their modified uterus until parturition. Males transfer their sperm and seminal fluid, produced by both testes and male accessory glands, in a spermatophore capsule transiently formed within the female reproductive tract upon mating. Both sexes are obligate blood feeders and have evolved tight relationships with endosymbionts, already shown to provide essential nutrients lacking in their diet. However, the partnership between tsetse and its symbionts has so far been investigated, at the molecular, genomic and metabolomics level, only in females, whereas the roles of microbiota in male reproduction are still unexplored.

Results: Here we begin unravelling the impact of microbiota on Glossina m. morsitans (G. morsitans) male reproductive biology by generating transcriptomes from the reproductive tissues of males deprived of their endosymbionts (aposymbiotic) via maternal antibiotic treatment and dietary supplementation. We then compared the transcriptional profiles of genes expressed in the male reproductive tract of normal and these aposymbiotic flies. We showed that microbiota removal impacts several male reproductive genes by depressing the activity of genes in the male accessory glands (MAGs), including sequences encoding seminal fluid proteins, and increasing expression of genes in the testes. In the MAGs, in particular, the expression of genes related to mating, immunity and seminal fluid components' synthesis is reduced. In the testes, the absence of symbionts activates genes involved in the metabolic apparatus at the basis of male reproduction, including sperm production, motility and function.

Conclusions: Our findings mirrored the complementary roles male accessory glands and testes play in supporting male reproduction and open new avenues for disentangling the interplay between male insects and endosymbionts. From an applied perspective, unravelling the metabolic and functional relationships between tsetse symbionts and male reproductive physiology will provide fundamental information useful to understanding the biology underlying improved male reproductive success in tsetse. This information is of particular importance in the context of tsetse population control via Sterile Insect Technique (SIT) and its impact on trypanosomiasis transmission.
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http://dx.doi.org/10.1186/s12866-018-1289-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6251095PMC
November 2018

Analysis of the gut-specific microbiome from field-captured tsetse flies, and its potential relevance to host trypanosome vector competence.

BMC Microbiol 2018 11 23;18(Suppl 1):146. Epub 2018 Nov 23.

Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT, USA.

Background: The tsetse fly (Glossina sp.) midgut is colonized by maternally transmitted and environmentally acquired bacteria. Additionally, the midgut serves as a niche in which pathogenic African trypanosomes reside within infected flies. Tsetse's bacterial microbiota impacts many aspects of the fly's physiology. However, little is known about the structure of tsetse's midgut-associated bacterial communities as they relate to geographically distinct fly habitats in east Africa and their contributions to parasite infection outcomes. We utilized culture dependent and independent methods to characterize the taxonomic structure and density of bacterial communities that reside within the midgut of tsetse flies collected at geographically distinct locations in Kenya and Uganda.

Results: Using culture dependent methods, we isolated 34 strains of bacteria from four different tsetse species (G. pallidipes, G. brevipalpis, G. fuscipes and G. fuscipleuris) captured at three distinct locations in Kenya. To increase the depth of this study, we deep sequenced midguts from individual uninfected and trypanosome infected G. pallidipes captured at two distinct locations in Kenya and one in Uganda. We found that tsetse's obligate endosymbiont, Wigglesworthia, was the most abundant bacterium present in the midgut of G. pallidipes, and the density of this bacterium remained largely consistent regardless of whether or not its tsetse host was infected with trypanosomes. These fly populations also housed the commensal symbiont Sodalis, which was found at significantly higher densities in trypanosome infected compared to uninfected flies. Finally, midguts of field-captured G. pallidipes were colonized with distinct, low density communities of environmentally acquired microbes that differed in taxonomic structure depending on parasite infection status and the geographic location from which the flies were collected.

Conclusions: The results of this study will enhance our understanding of the tripartite relationship between tsetse, its microbiota and trypanosome vector competence. This information may be useful for developing novel disease control strategies or enhancing the efficacy of those already in use.
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http://dx.doi.org/10.1186/s12866-018-1284-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6251097PMC
November 2018

A fine-tuned vector-parasite dialogue in tsetse's cardia determines peritrophic matrix integrity and trypanosome transmission success.

PLoS Pathog 2018 04 3;14(4):e1006972. Epub 2018 Apr 3.

Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, Connecticut, United States of America.

Arthropod vectors have multiple physical and immunological barriers that impede the development and transmission of parasites to new vertebrate hosts. These barriers include the peritrophic matrix (PM), a chitinous barrier that separates the blood bolus from the midgut epithelia and modulates vector-pathogens interactions. In tsetse flies, a sleeve-like PM is continuously produced by the cardia organ located at the fore- and midgut junction. African trypanosomes, Trypanosoma brucei, must bypass the PM twice; first to colonize the midgut and secondly to reach the salivary glands (SG), to complete their transmission cycle in tsetse. However, not all flies with midgut infections develop mammalian transmissible SG infections-the reasons for which are unclear. Here, we used transcriptomics, microscopy and functional genomics analyses to understand the factors that regulate parasite migration from midgut to SG. In flies with midgut infections only, parasites fail to cross the PM as they are eliminated from the cardia by reactive oxygen intermediates (ROIs)-albeit at the expense of collateral cytotoxic damage to the cardia. In flies with midgut and SG infections, expression of genes encoding components of the PM is reduced in the cardia, and structural integrity of the PM barrier is compromised. Under these circumstances trypanosomes traverse through the newly secreted and compromised PM. The process of PM attrition that enables the parasites to re-enter into the midgut lumen is apparently mediated by components of the parasites residing in the cardia. Thus, a fine-tuned dialogue between tsetse and trypanosomes at the cardia determines the outcome of PM integrity and trypanosome transmission success.
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http://dx.doi.org/10.1371/journal.ppat.1006972DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5898766PMC
April 2018

Molecular characterization of tsetse's proboscis and its response to Trypanosoma congolense infection.

PLoS Negl Trop Dis 2017 Nov 20;11(11):e0006057. Epub 2017 Nov 20.

Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT, United States of America.

Tsetse flies (Glossina spp.) transmit parasitic African trypanosomes (Trypanosoma spp.), including Trypanosoma congolense, which causes animal African trypanosomiasis (AAT). AAT detrimentally affects agricultural activities in sub-Saharan Africa and has negative impacts on the livelihood and nutrient availability for the affected communities. After tsetse ingests an infectious blood meal, T. congolense sequentially colonizes the fly's gut and proboscis (PB) organs before being transmitted to new mammalian hosts during subsequent feedings. Despite the importance of PB in blood feeding and disease transmission, little is known about its molecular composition, function and response to trypanosome infection. To bridge this gap, we used RNA-seq analysis to determine its molecular characteristics and responses to trypanosome infection. By comparing the PB transcriptome to whole head and midgut transcriptomes, we identified 668 PB-enriched transcripts that encoded proteins associated with muscle tissue, organ development, chemosensation and chitin-cuticle structure development. Moreover, transcripts encoding putative mechanoreceptors that monitor blood flow during tsetse feeding and interact with trypanosomes were also expressed in the PB. Microscopic analysis of the PB revealed cellular structures associated with muscles and cells. Infection with T. congolense resulted in increased and decreased expression of 38 and 88 transcripts, respectively. Twelve of these differentially expressed transcripts were PB-enriched. Among the transcripts induced upon infection were those encoding putative proteins associated with cell division function(s), suggesting enhanced tissue renewal, while those suppressed were associated with metabolic processes, extracellular matrix and ATP-binding as well as immunity. These results suggest that PB is a muscular organ with chemosensory and mechanosensory capabilities. The mechanoreceptors may be point of PB-trypanosomes interactions. T. congolense infection resulted in reduced metabolic and immune capacity of the PB. The molecular knowledge on the composition and putative functions of PB forms the foundation to identify new targets to disrupt tsetse's ability to feed and parasite transmission.
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http://dx.doi.org/10.1371/journal.pntd.0006057DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5695773PMC
November 2017

MicroRNA-277 targets and to control lipid metabolism and reproduction in mosquitoes.

Proc Natl Acad Sci U S A 2017 09 5;114(38):E8017-E8024. Epub 2017 Sep 5.

Department of Entomology, University of California, Riverside, CA 92521;

Hematophagous female mosquitoes transmit numerous devastating human diseases, including malaria, dengue fever, Zika virus, and others. Because of their obligatory requirement of a vertebrate blood meal for reproduction, these mosquitoes need a lot of energy; therefore, understanding the molecular mechanisms linking metabolism and reproduction is of particular importance. Lipids are the major energy store providing the fuel required for host seeking and reproduction. They are essential components of the fat body, a metabolic tissue that is the insect analog of vertebrate liver and adipose tissue. In this study, we found that microRNA-277 (miR-277) plays an important role in regulating mosquito lipid metabolism. The genetic disruption of miR-277 using the CRISPR-Cas9 system led to failures in both lipid storage and ovary development. miR-277 mimic injection partially rescued these phenotypic manifestations. Examination of subcellular localization of FOXO protein via CRISPR-assisted, single-stranded oligodeoxynucleotide-mediated homology-directed repair revealed that insulin signaling is up-regulated in response to miR-277 depletion. In silico target prediction identified that insulin-like peptides 7 and 8 ( and ) are putative targets of miR-277; RNA immunoprecipitation and a luciferase reporter assay confirmed that and are direct targets of this miRNA. CRISPR-Cas9 depletion of and led to metabolic and reproductive defects. These depletions identified differential actions of ILP7 and ILP8 in lipid homeostasis and ovarian development. Thus, miR-277 plays a critical role in mosquito lipid metabolism and reproduction by targeting and , and serves as a monitor to control ILP7 and ILP8 mRNA levels.
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http://dx.doi.org/10.1073/pnas.1710970114DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5617303PMC
September 2017

Genome-wide analysis of gene expression profiling revealed that COP9 signalosome is essential for correct expression of Fe homeostasis genes in Arabidopsis.

Biometals 2017 Oct 25;30(5):685-698. Epub 2017 Jul 25.

Department of Agricultural Genetic Engineering, Ayhan Sahenk Faculty of Agricultural Sciences and Technologies, Ömer Halisdemir University, Merkez, 51240, Nigde, Turkey.

In plant cells, either excess or insufficient iron (Fe) concentration triggers stress responses, therefore it is strictly controlled. Proteasome-mediated degradation through ubiquitination of Fe homeostasis proteins has just become the focus of research in recent years. Deactivating ubiquitin ligases, COP9 signalosome has a central importance in the translational control of various stress responses. The aim of the study was to investigate COP9 signalosome in Fe deficiency response of Strategy I plants. In silico analysis of a set of Fe-deficiency-responsive genes was conducted against the transcriptome of Arabidopsis csn mutant lines using Genevestigator software. Induced and suppressed genes were clustered in a hierarchical way and gene ontology enrichment categories were identified. In wild-type Arabidopsis, CSN genes did not respond to iron deficiency. In csn mutant lines, under Fe-sufficient conditions, hundreds of Fe-deficiency-responsive genes were misregulated. Among the ones previously characterized for their physiological roles under Fe deficiency IRT1, NAS4, BTS, NRAMP1 were down-regulated while AHA2, MTP8, FRD3 were up-regulated. Unexpectedly, from those which were regulated in opposite ways, some had been repeatedly shown to be tightly co-regulated by the same transcription factor, FIT. Two proteins from DELLA family, which were reported to interact with FIT to repress its downstream, were found to be strikingly repressed in csn mutants. Overall, the study underlined that the absence of a functional CSN greatly impacted the regulation of Fe homeostasis-related genes, in a manner which cannot be explained simply by the induction of the master transcription factor, FIT. Correct expression of Fe deficiency-responsive genes requires an intact COP9 signalosome in Arabidopsis.
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http://dx.doi.org/10.1007/s10534-017-0036-8DOI Listing
October 2017

Unravelling the relationship between the tsetse fly and its obligate symbiont : transcriptomic and metabolomic landscapes reveal highly integrated physiological networks.

Proc Biol Sci 2017 Jun;284(1857)

Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT 06520, USA

Insects with restricted diets rely on obligate microbes to fulfil nutritional requirements essential for biological function. Tsetse flies, vectors of African trypanosome parasites, feed exclusively on vertebrate blood and harbour the obligate endosymbiont Without , tsetse are unable to reproduce. These symbionts are sheltered within specialized cells (bacteriocytes) that form the midgut-associated bacteriome organ. To decipher the core functions of this symbiosis essential for tsetse's survival, we performed dual-RNA-seq analysis of the bacteriome, coupled with metabolomic analysis of bacteriome and haemolymph collected from normal and symbiont-cured (sterile) females. Bacteriocytes produce immune regulatory peptidoglycan recognition protein () that protects , and a multivitamin transporter () that can aid in nutrient dissemination. overexpress a molecular chaperone (GroEL) to augment their translational/transport machinery and biosynthesize an abundance of B vitamins (specifically B-, B-, B- and B-associated metabolites) to supplement the host's nutritionally deficient diet. The absence of contributions disrupts multiple metabolic pathways impacting carbohydrate and amino acid metabolism. These disruptions affect the dependent downstream processes of nucleotide biosynthesis and metabolism and biosynthesis of -adenosyl methionine (SAM), an essential cofactor. This holistic fundamental knowledge of the symbiotic dialogue highlights new biological targets for the development of innovative vector control methods.
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http://dx.doi.org/10.1098/rspb.2017.0360DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5489720PMC
June 2017

Filthy lucre: A metagenomic pilot study of microbes found on circulating currency in New York City.

PLoS One 2017 6;12(4):e0175527. Epub 2017 Apr 6.

Center for Genomics and Systems Biology, Department of Biology, New York University, New York, United States of America.

Background: Paper currency by its very nature is frequently transferred from one person to another and represents an important medium for human contact with-and potential exchange of-microbes. In this pilot study, we swabbed circulating $1 bills obtained from a New York City bank in February (Winter) and June (Summer) 2013 and used shotgun metagenomic sequencing to profile the communities found on their surface. Using basic culture conditions, we also tested whether viable microbes could be recovered from bills.

Results: Shotgun metagenomics identified eukaryotes as the most abundant sequences on money, followed by bacteria, viruses and archaea. Eukaryotic assemblages were dominated by human, other metazoan and fungal taxa. The currency investigated harbored a diverse microbial population that was dominated by human skin and oral commensals, including Propionibacterium acnes, Staphylococcus epidermidis and Micrococcus luteus. Other taxa detected not associated with humans included Lactococcus lactis and Streptococcus thermophilus, microbes typically associated with dairy production and fermentation. Culturing results indicated that viable microbes can be isolated from paper currency.

Conclusions: We conducted the first metagenomic characterization of the surface of paper money in the United States, establishing a baseline for microbes found on $1 bills circulating in New York City. Our results suggest that money amalgamates DNA from sources inhabiting the human microbiome, food, and other environmental inputs, some of which can be recovered as viable organisms. These monetary communities may be maintained through contact with human skin, and DNA obtained from money may provide a record of human behavior and health. Understanding these microbial profiles is especially relevant to public health as money could potentially mediate interpersonal transfer of microbes.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0175527PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5383295PMC
September 2017

Transcriptome-wide microRNA and target dynamics in the fat body during the gonadotrophic cycle of .

Proc Natl Acad Sci U S A 2017 03 21;114(10):E1895-E1903. Epub 2017 Feb 21.

Institute of Integrative Genome Biology, University of California, Riverside, CA 92521;

The mosquito is a major vector of numerous viral diseases, because it requires a blood meal to facilitate egg development. The fat body, a counterpart of mammalian liver and adipose tissues, is the metabolic center, playing a key role in reproduction. Therefore, understanding of regulatory networks controlling its functions is critical, and the role of microRNAs (miRNAs) in the process is largely unknown. We aimed to explore miRNA expression and potential targets in the female fat body of , as well as their changes postblood meal (PBM). Small RNA library analysis revealed five unique miRNA patterns sequentially expressed at five sampled time points, likely responding to, and affecting, waves of upstream hormonal signals and gene expression in the same period. To link miRNA identities with downstream targets, transcriptome-wide mRNA 3' UTR interaction sites were experimentally determined at 72 h posteclosion and 24 h PBM through Argonaute 1 cross-linking and immunoprecipitation followed by high-throughput sequencing. Several target sites were validated by means of in vitro luciferase assays with wild-type and mutated 3' UTRs for six miRNA families. With established transgenic lines, consistent results were observed with spatiotemporal knockdown of miR-8 and luciferase assays. We further investigated miRNAs potentially regulating various physiological processes based on Clusters of Orthologous Groups functional categories. Hence, the present work comprehensively elucidated miRNA expression and target dynamics in the female mosquito fat body, providing a solid foundation for future functional studies of miRNA regulation during the gonadotrophic cycle.
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http://dx.doi.org/10.1073/pnas.1701474114DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5347622PMC
March 2017

Mammalian African trypanosome VSG coat enhances tsetse's vector competence.

Proc Natl Acad Sci U S A 2016 06 16;113(25):6961-6. Epub 2016 May 16.

Department of Epidemiology of Microbial Diseases, Yale School of Public Health, Yale University, New Haven, CT 06520;

Tsetse flies are biological vectors of African trypanosomes, the protozoan parasites responsible for causing human and animal trypanosomiases across sub-Saharan Africa. Currently, no vaccines are available for disease prevention due to antigenic variation of the Variant Surface Glycoproteins (VSG) that coat parasites while they reside within mammalian hosts. As a result, interference with parasite development in the tsetse vector is being explored to reduce disease transmission. A major bottleneck to infection occurs as parasites attempt to colonize tsetse's midgut. One critical factor influencing this bottleneck is the fly's peritrophic matrix (PM), a semipermeable, chitinous barrier that lines the midgut. The mechanisms that enable trypanosomes to cross this barrier are currently unknown. Here, we determined that as parasites enter the tsetse's gut, VSG molecules released from trypanosomes are internalized by cells of the cardia-the tissue responsible for producing the PM. VSG internalization results in decreased expression of a tsetse microRNA (mir-275) and interferes with the Wnt-signaling pathway and the Iroquois/IRX transcription factor family. This interference reduces the function of the PM barrier and promotes parasite colonization of the gut early in the infection process. Manipulation of the insect midgut homeostasis by the mammalian parasite coat proteins is a novel function and indicates that VSG serves a dual role in trypanosome biology-that of facilitating transmission through its mammalian host and insect vector. We detail critical steps in the course of trypanosome infection establishment that can serve as novel targets to reduce the tsetse's vector competence and disease transmission.
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http://dx.doi.org/10.1073/pnas.1600304113DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4922192PMC
June 2016

The Spermatophore in Glossina morsitans morsitans: Insights into Male Contributions to Reproduction.

Sci Rep 2016 Feb 5;6:20334. Epub 2016 Feb 5.

Yale School of Public Health, Dept of Epidemiology of Microbial Diseases, 06520, New Haven, CT, USA.

Male Seminal Fluid Proteins (SFPs) transferred during copulation modulate female reproductive physiology and behavior, impacting sperm storage/use, ovulation, oviposition, and remating receptivity. These capabilities make them ideal targets for developing novel methods of insect disease vector control. Little is known about the nature of SFPs in the viviparous tsetse flies (Diptera: Glossinidae), vectors of Human and Animal African trypanosomiasis. In tsetse, male ejaculate is assembled into a capsule-like spermatophore structure visible post-copulation in the female uterus. We applied high-throughput approaches to uncover the composition of the spermatophore in Glossina morsitans morsitans. We found that both male accessory glands and testes contribute to its formation. The male accessory glands produce a small number of abundant novel proteins with yet unknown functions, in addition to enzyme inhibitors and peptidase regulators. The testes contribute sperm in addition to a diverse array of less abundant proteins associated with binding, oxidoreductase/transferase activities, cytoskeletal and lipid/carbohydrate transporter functions. Proteins encoded by female-biased genes are also found in the spermatophore. About half of the proteins display sequence conservation relative to other Diptera, and low similarity to SFPs from other studied species, possibly reflecting both their fast evolutionary pace and the divergent nature of tsetse's viviparous biology.
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http://dx.doi.org/10.1038/srep20334DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4742874PMC
February 2016

Insects recycle endosymbionts when the benefit is over.

Curr Biol 2014 Oct 18;24(19):2267-73. Epub 2014 Sep 18.

Biologie Fonctionnelle Insectes et Interactions, UMR203 BF2I, INRA, INSA-Lyon, Université de Lyon, 69621 Villeurbanne, France. Electronic address:

Symbiotic associations are widespread in nature and represent a driving force in evolution. They are known to impact fitness, and thereby shape the host phenotype. Insects subsisting on nutritionally poor substrates have evolved mutualistic relationships with intracellular symbiotic bacteria (endosymbionts) that supply them with metabolic components lacking in their diet. In many species, endosymbionts are hosted within specialized host cells, called the bacteriocytes, and transmitted vertically across host generations. How hosts balance the costs and benefits of having endosymbionts, and whether and how they adjust symbiont load to their physiological needs, remains largely unexplored. By investigating the cereal weevil Sitophilus association with the Sodalis pierantonius endosymbiont, we discover that endosymbiont populations intensively multiply in young adults, before being rapidly eliminated within few days. We show that young adults strongly depend on endosymbionts and that endosymbiont proliferation after metamorphosis matches a drastic host physiological need for the tyrosine (Tyr) and phenylalanine (Phe) amino acids to rapidly build their protective exoskeleton. Tyr and Phe are precursors of the dihydroxyphenylalanine (DOPA) molecule that is an essential component for the cuticle synthesis. Once the cuticle is achieved, DOPA reaches high amounts in insects, which triggers endosymbiont elimination. This elimination relies on apoptosis and autophagy activation, allowing digestion and recycling of the endosymbiont material. Thus, the weevil-endosymbiont association reveals an adaptive interplay between metabolic and cellular functions that minimizes the cost of symbiosis and speeds up the exoskeleton formation during a critical phase when emerging adults are especially vulnerable.
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http://dx.doi.org/10.1016/j.cub.2014.07.065DOI Listing
October 2014

Arabidopsis CPL4 is an essential C-terminal domain phosphatase that suppresses xenobiotic stress responses.

Plant J 2014 Oct 5;80(1):27-39. Epub 2014 Aug 5.

Molecular and Environmental Plant Sciences, Department of Horticultural Sciences, Vegetable and Fruit Development Center, Texas A&M University, College Station, TX, 77843, USA.

Eukaryotic gene expression is both promoted and inhibited by the reversible phosphorylation of the C-terminal domain of RNA polymerase II (pol II CTD). More than 20 Arabidopsis genes encode CTD phosphatase homologs, including four CTD phosphatase-like (CPL) family members. Although in vitro CTD phosphatase activity has been established for some CPLs, none have been shown to be involved in the phosphoregulation of pol II in vivo. Here we report that CPL4 is a CTD phosphatase essential for the viability of Arabidopsis thaliana. Mass spectrometry analysis identified the pol II subunits RPB1, RPB2 and RPB3 in the affinity-purified CPL4 complex. CPL4 dephosphorylates both Ser2- and Ser5-PO(4) of the CTD in vitro, with a preference for Ser2-PO(4). Arabidopsis plants overexpressing CPL4 accumulated hypophosphorylated pol II, whereas RNA interference-mediated silencing of CPL4 promoted hyperphosphorylation of pol II. A D128A mutation in the conserved DXDXT motif of the CPL4 catalytic domain resulted in a dominant negative form of CPL4, the overexpression of which inhibited transgene expression in transient assays. Inhibition was abolished by truncation of the phosphoprotein-binding Breast Cancer 1 C-terminal domain of CPL4, suggesting that both catalytic function and protein-protein interaction are essential for CPL4-mediated regulation of gene expression. We were unable to recover a homozygous cpl4 mutant, probably due to the zygotic lethality of this mutation. The reduction in CPL4 levels in CPL4(RNAi) plants increased transcript levels of a suite of herbicide/xenobiotic-responsive genes and improved herbicide tolerance, thus suggesting an additional role for CPL4 as a negative regulator of the xenobiotic detoxification pathway.
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http://dx.doi.org/10.1111/tpj.12612DOI Listing
October 2014

Analysis of multiple tsetse fly populations in Uganda reveals limited diversity and species-specific gut microbiota.

Appl Environ Microbiol 2014 Jul 9;80(14):4301-12. Epub 2014 May 9.

Department of Ecology and Evolutionary Biology, Yale University, New Haven, Connecticut, USA Department of Epidemiology of Microbial Diseases, Yale School of Public Health, Yale University, New Haven, Connecticut, USA.

The invertebrate microbiome contributes to multiple aspects of host physiology, including nutrient supplementation and immune maturation processes. We identified and compared gut microbial abundance and diversity in natural tsetse flies from Uganda using five genetically distinct populations of Glossina fuscipes fuscipes and multiple tsetse species (Glossina morsitans morsitans, G. f. fuscipes, and Glossina pallidipes) that occur in sympatry in one location. We used multiple approaches, including deep sequencing of the V4 hypervariable region of the 16S rRNA gene, 16S rRNA gene clone libraries, and bacterium-specific quantitative PCR (qPCR), to investigate the levels and patterns of gut microbial diversity from a total of 151 individuals. Our results show extremely limited diversity in field flies of different tsetse species. The obligate endosymbiont Wigglesworthia dominated all samples (>99%), but we also observed wide prevalence of low-density Sodalis (tsetse's commensal endosymbiont) infections (<0.05%). There were also several individuals (22%) with high Sodalis density, which also carried coinfections with Serratia. Albeit in low density, we noted differences in microbiota composition among the genetically distinct G. f. fuscipes flies and between different sympatric species. Interestingly, Wigglesworthia density varied in different species (10(4) to 10(6) normalized genomes), with G. f. fuscipes having the highest levels. We describe the factors that may be responsible for the reduced diversity of tsetse's gut microbiota compared to those of other insects. Additionally, we discuss the implications of Wigglesworthia and Sodalis density variations as they relate to trypanosome transmission dynamics and vector competence variations associated with different tsetse species.
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http://dx.doi.org/10.1128/AEM.00079-14DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4068677PMC
July 2014

Regulation of abiotic stress signalling by Arabidopsis C-terminal domain phosphatase-like 1 requires interaction with a k-homology domain-containing protein.

PLoS One 2013 26;8(11):e80509. Epub 2013 Nov 26.

Department of Horticultural Sciences, Texas A&M University, College Station, Texas, United States of America ; Division of Applied Life Science (BK21 Program), Graduate School of Gyeongsang National University, Jinju, Gyeongsangnam-do, Korea.

Arabidopsis thaliana CARBOXYL-TERMINAL DOMAIN (CTD) PHOSPHATASE-LIKE 1 (CPL1) regulates plant transcriptional responses to diverse stress signals. Unlike typical CTD phosphatases, CPL1 contains two double-stranded (ds) RNA binding motifs (dsRBMs) at its C-terminus. Some dsRBMs can bind to dsRNA and/or other proteins, but the function of the CPL1 dsRBMs has remained obscure. Here, we report identification of REGULATOR OF CBF GENE EXPRESSION 3 (RCF3) as a CPL1-interacting protein. RCF3 co-purified with tandem-affinity-tagged CPL1 from cultured Arabidopsis cells and contains multiple K-homology (KH) domains, which were predicted to be important for binding to single-stranded DNA/RNA. Yeast two-hybrid, luciferase complementation imaging, and bimolecular fluorescence complementation analyses established that CPL1 and RCF3 strongly associate in vivo, an interaction mediated by the dsRBM1 of CPL1 and the KH3/KH4 domains of RCF3. Mapping of functional regions of CPL1 indicated that CPL1 in vivo function requires the dsRBM1, catalytic activity, and nuclear targeting of CPL1. Gene expression profiles of rcf3 and cpl1 mutants were similar during iron deficiency, but were distinct during the cold response. These results suggest that tethering CPL1 to RCF3 via dsRBM1 is part of the mechanism that confers specificity to CPL1-mediated transcriptional regulation.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0080509PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3841200PMC
October 2014

Arabidopsis C-terminal domain phosphatase-like 1 functions in miRNA accumulation and DNA methylation.

PLoS One 2013 18;8(9):e74739. Epub 2013 Sep 18.

Division of Applied Life Science (BK21 Program), Graduate School of Gyeongsang National University, Jinju, Gyeongsangnam-do, Korea ; Department of Horticultural Sciences, Texas A&M University, College Station, Texas, United States of America.

Arabidopsis CTD-PHOSPHATASE-LIKE 1 (CPL1) is a protein phosphatase that can dephosphorylate RNA polymerase II C-terminal domain (CTD). Unlike typical CTD-phosphatases, CPL1 contains a double-stranded (ds) RNA-binding motif (dsRBM) and has been implicated for gene regulation mediated by dsRNA-dependent pathways. We investigated the role of CPL1 and its dsRBMs in various gene silencing pathways. Genetic interaction analyses revealed that cpl1 was able to partially suppress transcriptional gene silencing and DNA hypermethylation phenotype of ros1 suggesting CPL1 is involved in the RNA-directed DNA methylation pathway without reducing siRNA production. By contrast, cpl1 reduced some miRNA levels at the level of processing. Indeed, CPL1 protein interacted with proteins important for miRNA biogenesis, suggesting that CPL1 regulates miRNA processing. These results suggest that CPL1 regulates DNA methylation via a miRNA-dependent pathway.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0074739PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3776750PMC
June 2014

Wolbachia, Sodalis and trypanosome co-infections in natural populations of Glossina austeni and Glossina pallidipes.

Parasit Vectors 2013 Aug 8;6(1):232. Epub 2013 Aug 8.

KARI-Trypanosomiasis Research Centre, Kikuyu, Kenya.

Background: Tsetse flies harbor at least three bacterial symbionts: Wigglesworthia glossinidia, Wolbachia pipientis and Sodalis glossinidius. Wigglesworthia and Sodalis reside in the gut in close association with trypanosomes and may influence establishment and development of midgut parasite infections. Wolbachia has been shown to induce reproductive effects in infected tsetse. This study was conducted to determine the prevalence of these endosymbionts in natural populations of G. austeni and G. pallidipes and to assess the degree of concurrent infections with trypanosomes.

Methods: Fly samples analyzed originated from Kenyan coastal forests (trapped in 2009-2011) and South African G. austeni collected in 2008. The age structure was estimated by standard methods. G. austeni (n=298) and G. pallidipes (n= 302) were analyzed for infection with Wolbachia and Sodalis using PCR. Trypanosome infection was determined either by microscopic examination of dissected organs or by PCR amplification.

Results: Overall we observed that G. pallidipes females had a longer lifespan (70 d) than G. austeni (54 d) in natural populations. Wolbachia infections were present in all G. austeni flies analysed, while in contrast, this symbiont was absent from G. pallidipes. The density of Wolbachia infections in the Kenyan G. austeni population was higher than that observed in South African flies. The infection prevalence of Sodalis ranged from 3.7% in G. austeni to about 16% in G. pallidipes. Microscopic examination of midguts revealed an overall trypanosome infection prevalence of 6% (n = 235) and 5% (n = 552), while evaluation with ITS1 primers indicated a prevalence of about 13% (n = 296) and 10% (n = 302) in G. austeni and G. pallidipes, respectively. The majority of infections (46%) were with T. congolense. Co-infection with all three organisms was observed at 1% and 3.3% in G. austeni and G. pallidipes, respectively. Eleven out of the thirteen (85%) co-infected flies harboured T. congolense and T. simiae parasites. While the association between trypanosomes and Sodalis infection was statistically significant in G. pallidipes (P = 0.0127), the number of co-infected flies was too few for a definite conclusion.

Conclusions: The tsetse populations analyzed differed in the prevalence of symbionts, despite being sympatric and therefore exposed to identical environmental factors. The density of infections with Wolbachia also differed between G. austeni populations. There were too few natural co-infections detected with the Sodalis and trypanosomes to suggest extensive inter-relations between these infections in natural populations. We discuss these findings in the context of potential symbiont-mediated control interventions to reduce parasite infections and/or fly populations.
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http://dx.doi.org/10.1186/1756-3305-6-232DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3751944PMC
August 2013

Function of Arabidopsis CPL1 in cadmium responses.

Plant Signal Behav 2013 May 1;8(5):e24120. Epub 2013 Mar 1.

Molecular and Environmental Plant Sciences; Vegetable and Fruit Development Center; Department of Horticultural Sciences; Texas A&M University; College Station, TX USA.

Transcriptional and post-transcriptional responses to external iron (Fe) availability are essential for the cellular Fe homeostasis. Fe deficiency strongly induces Fe utilization-related gene expression; however, little is known about the early Fe signaling that regulates expression of a central transcription factor FIT. In Arabidopsis, mutations in RNA polymerase II CTD-phosphatase-like 1 (CPL1) enhance the expression of Fe utilization-related genes including FIT under Fe deficiency. Fe content is significantly increased in the roots and decreased in the shoots of cpl1-2 plants, and root growth of the cpl1-2 mutant shows higher tolerance to Fe deficiency and to toxicity of cadmium (Cd). The cpl1-2 plants accumulate more Cd in the shoots, suggesting that Cd toxicity in the cpl1-2 roots is circumvented by the transport of excess Cd to the shoots. Here we show data suggesting that the root-to-shoot translocation of Cd in cpl1-2 is mediated by yet uncharacterized Cd transport mechanisms.
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http://dx.doi.org/10.4161/psb.24120DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3897498PMC
May 2013

Loss of function of Arabidopsis C-terminal domain phosphatase-like1 activates iron deficiency responses at the transcriptional level.

Plant Physiol 2013 Jan 9;161(1):330-45. Epub 2012 Nov 9.

Molecular and Environmental Plant Sciences , Texas A&M University, College Station, Texas 77843, USA.

The expression of genes that control iron (Fe) uptake and distribution (i.e. Fe utilization-related genes) is tightly regulated. Fe deficiency strongly induces Fe utilization-related gene expression; however, little is known about the mechanisms that regulate this response in plants. Transcriptome analysis of an Arabidopsis (Arabidopsis thaliana) mutant defective in RNA polymerase II C-terminal domain-phosphatase-like1 (CPL1) revealed significant up-regulation of Fe utilization-related genes (e.g. IRON-REGULATED TRANSPORTER1), suggesting the importance of RNA metabolism in Fe signaling. An analysis using multiple cpl1 alleles established that cpl1 mutations enhanced specific transcriptional responses to low Fe availability. Changes in protein level were less prominent than those in transcript level, indicating that cpl1-2 mainly affects the Fe deficiency response at the transcriptional level. However, Fe content was significantly increased in the roots and decreased in the shoots of cpl1-2 plants, indicating that the cpl1 mutations do indeed affect Fe homeostasis. Furthermore, root growth of cpl1-2 showed improved tolerance to Fe deficiency and cadmium (Cd) toxicity. cpl1-2 plants accumulated more Cd in the shoots, suggesting that Cd toxicity in the roots of this mutant is averted by the transport of excess Cd to the shoots. Genetic data indicate that cpl1-2 likely activates Fe deficiency responses upstream of both FE-DEFICIENCY-INDUCED TRANSCRIPTION FACTOR-dependent and -independent signaling pathways. Interestingly, various osmotic stress/abscisic acid (ABA)-inducible genes were up-regulated in cpl1-2, and the expression of some ABA-inducible genes was controlled by Fe availability. We propose that the cpl1 mutations enhance Fe deficiency signaling and promote cross talk with a branch of the osmotic stress/ABA signaling pathway.
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http://dx.doi.org/10.1104/pp.112.207043DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3532264PMC
January 2013

Tsetse-Wolbachia symbiosis: comes of age and has great potential for pest and disease control.

J Invertebr Pathol 2013 Mar 23;112 Suppl:S94-103. Epub 2012 Jul 23.

Department of Environmental and Natural Resources Management, University of Ioannina, 2 Seferi St., 30100 Agrinio, Greece.

Tsetse flies (Diptera: Glossinidae) are the sole vectors of African trypanosomes, the causative agent of sleeping sickness in human and nagana in animals. Like most eukaryotic organisms, Glossina species have established symbiotic associations with bacteria. Three main symbiotic bacteria have been found in tsetse flies: Wigglesworthia glossinidia, an obligate symbiotic bacterium, the secondary endosymbiont Sodalis glossinidius and the reproductive symbiont Wolbachia pipientis. In the present review, we discuss recent studies on the detection and characterization of Wolbachia infections in Glossina species, the horizontal transfer of Wolbachia genes to tsetse chromosomes, the ability of this symbiont to induce cytoplasmic incompatibility in Glossina morsitans morsitans and also how new environment-friendly tools for disease control could be developed by harnessing Wolbachia symbiosis.
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http://dx.doi.org/10.1016/j.jip.2012.05.010DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3772542PMC
March 2013

Detection and characterization of Wolbachia infections in laboratory and natural populations of different species of tsetse flies (genus Glossina).

BMC Microbiol 2012 Jan 18;12 Suppl 1:S3. Epub 2012 Jan 18.

Background: Wolbachia is a genus of endosymbiotic α-Proteobacteria infecting a wide range of arthropods and filarial nematodes. Wolbachia is able to induce reproductive abnormalities such as cytoplasmic incompatibility (CI), thelytokous parthenogenesis, feminization and male killing, thus affecting biology, ecology and evolution of its hosts. The bacterial group has prompted research regarding its potential for the control of agricultural and medical disease vectors, including Glossina spp., which transmits African trypanosomes, the causative agents of sleeping sickness in humans and nagana in animals.

Results: In the present study, we employed a Wolbachia specific 16S rRNA PCR assay to investigate the presence of Wolbachia in six different laboratory stocks as well as in natural populations of nine different Glossina species originating from 10 African countries. Wolbachia was prevalent in Glossina morsitans morsitans, G. morsitans centralis and G. austeni populations. It was also detected in G. brevipalpis, and, for the first time, in G. pallidipes and G. palpalis gambiensis. On the other hand, Wolbachia was not found in G. p. palpalis, G. fuscipes fuscipes and G. tachinoides. Wolbachia infections of different laboratory and natural populations of Glossina species were characterized using 16S rRNA, the wsp (Wolbachia Surface Protein) gene and MLST (Multi Locus Sequence Typing) gene markers. This analysis led to the detection of horizontal gene transfer events, in which Wobachia genes were inserted into the tsetse flies fly nuclear genome.

Conclusions: Wolbachia infections were detected in both laboratory and natural populations of several different Glossina species. The characterization of these Wolbachia strains promises to lead to a deeper insight in tsetse flies-Wolbachia interactions, which is essential for the development and use of Wolbachia-based biological control methods.
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http://dx.doi.org/10.1186/1471-2180-12-S1-S3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3287514PMC
January 2012
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