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McIntyre-Nolan S, Kumar V, Mark-Carew M, Kumar K, Nightingale ES, Dalla Libera Marchiori G, Rogers ME, Kristan M, Campino S, Medley GF, Das P, Cameron MM. Comparison of collection methods for Phlebotomus argentipes sand flies to use in a molecular xenomonitoring system for the surveillance of visceral leishmaniasis. PLoS Negl Trop Dis 2023; 17:e0011200. [PMID: 37656745 PMCID: PMC10501600 DOI: 10.1371/journal.pntd.0011200] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Revised: 09/14/2023] [Accepted: 08/14/2023] [Indexed: 09/03/2023] Open
Abstract
BACKGROUND The kala-azar elimination programme has resulted in a significant reduction in visceral leishmaniasis (VL) cases across the Indian Subcontinent. To detect any resurgence of transmission, a sensitive cost-effective surveillance system is required. Molecular xenomonitoring (MX), detection of pathogen DNA/RNA in vectors, provides a proxy of human infection in the lymphatic filariasis elimination programme. To determine whether MX can be used for VL surveillance in a low transmission setting, large numbers of the sand fly vector Phlebotomus argentipes are required. This study will determine the best method for capturing P. argentipes females for MX. METHODOLOGY/PRINCIPAL FINDINGS The field study was performed in two programmatic and two non-programmatic villages in Bihar, India. A total of 48 households (12/village) were recruited. Centers for Disease Control and Prevention light traps (CDC-LTs) were compared with Improved Prokopack (PKP) and mechanical vacuum aspirators (MVA) using standardised methods. Four 12x12 Latin squares, 576 collections, were attempted (12/house, 144/village,192/method). Molecular analyses of collections were conducted to confirm identification of P. argentipes and to detect human and Leishmania DNA. Operational factors, such as time burden, acceptance to householders and RNA preservation, were also considered. A total of 562 collections (97.7%) were completed with 6,809 sand flies captured. Females comprised 49.0% of captures, of which 1,934 (57.9%) were identified as P. argentipes. CDC-LTs collected 4.04 times more P. argentipes females than MVA and 3.62 times more than PKP (p<0.0001 for each). Of 21,735 mosquitoes in the same collections, no significant differences between collection methods were observed. CDC-LTs took less time to install and collect than to perform aspirations and their greater yield compensated for increased sorting time. No significant differences in Leishmania RNA detection and quantitation between methods were observed in experimentally infected sand flies maintained in conditions simulating field conditions. CDC-LTs were favoured by householders. CONCLUSIONS/SIGNIFICANCE CDC-LTs are the most useful collection tool of those tested for MX surveillance since they collected higher numbers of P. argentipes females without compromising mosquito captures or the preservation of RNA. However, capture rates are still low.
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Affiliation(s)
- Shannon McIntyre-Nolan
- Department of Disease Control, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Vijay Kumar
- Rajendra Memorial Research Institute of Medical Sciences, Patna, India
| | - Miguella Mark-Carew
- Department of Disease Control, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Kundan Kumar
- Rajendra Memorial Research Institute of Medical Sciences, Patna, India
| | - Emily S. Nightingale
- Department of Global Health and Development, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | | | - Matthew E. Rogers
- Department of Disease Control, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Mojca Kristan
- Department of Disease Control, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Susana Campino
- Department of Infection Biology, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Graham F. Medley
- Department of Global Health and Development, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Pradeep Das
- Department of Molecular Parasitology, National Institute of Cholera and Enteric Diseases, Kolkata, India
| | - Mary M. Cameron
- Department of Disease Control, London School of Hygiene & Tropical Medicine, London, United Kingdom
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Seow ES, Doran EC, Schroeder JH, Rogers ME, Raynes JG. C-reactive protein binds to short phosphoglycan repeats of Leishmania secreted proteophosphoglycans and activates complement. Front Immunol 2023; 14:1256205. [PMID: 37720216 PMCID: PMC10500826 DOI: 10.3389/fimmu.2023.1256205] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Accepted: 08/14/2023] [Indexed: 09/19/2023] Open
Abstract
Human C-reactive protein (CRP) binds to lipophosphoglycan (LPG), a virulence factor of Leishmania spp., through the repeating phosphodisaccharide region. We report here that both major components of promastigote secretory gel (PSG), the filamentous proteophosphoglycan (fPPG) and the secreted acid phosphatase (ScAP), are also ligands. CRP binding was mainly associated with the flagellar pocket when LPG deficient Leishmania mexicana parasites were examined by fluorescent microscopy, consistent with binding to secreted material. ScAP is a major ligand in purified fPPG from parasite culture as demonstrated by much reduced binding to a ScAP deficient mutant fPPG in plate binding assays and ligand blotting. Nevertheless, in sandfly derived PSG fPPG is a major component and the major CRP binding component. Previously we showed high avidity of CRP for LPG ligand required multiple disaccharide repeats. ScAP and fPPG only have short repeats but they retain high avidity for CRP revealed by surface plasmon resonance because they are found in multiple copies on the phosphoglycan. The fPPG from many species such as L. donovani and L. mexicana bound CRP strongly but L. tropica and L. amazonensis had low amounts of binding. The extent of side chain substitution of [-PO4-6Galβ1-4Manα1-] disaccharides correlates inversely with binding of CRP. The ligand for the CRP on different species all had similar binding avidity as the half maximal binding concentration was similar. Since the PSG is injected with the parasites into host blood pools and phosphoglycans (PG) are known to deplete complement, we showed that CRP makes a significant contribution to the activation of complement by PSG using serum from naive donors.
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Affiliation(s)
| | | | | | | | - John G. Raynes
- Department of Infection Biology, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
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Trimmer C, Arroyave R, Vuilleumier C, Wu L, Dumer A, DeLaura C, Kim J, Pierce GM, Borisovska M, De Nanteuil F, Emberger M, Varganov Y, Margot C, Rogers ME, Pfister P. Allosteric modulation of a human odorant receptor. Curr Biol 2023; 33:1523-1534.e4. [PMID: 36977419 DOI: 10.1016/j.cub.2023.03.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Revised: 12/02/2022] [Accepted: 03/06/2023] [Indexed: 03/29/2023]
Abstract
Odor perception is first determined by how the myriad of environmental volatiles are detected at the periphery of the olfactory system. The combinatorial activation of dedicated odorant receptors generates enough encoding power for the discrimination of tens of thousands of odorants. Recent studies have revealed that odorant receptors undergo widespread inhibitory modulation of their activity when presented with mixtures of odorants, a property likely required to maintain discrimination and ensure sparsity of the code for complex mixtures. Here, we establish the role of human OR5AN1 in the detection of musks and identify distinct odorants capable of enhancing its activity in binary mixtures. Chemical and pharmacological characterization indicate that specific α-β unsaturated aliphatic aldehydes act as positive allosteric modulators. Sensory experiments show decreased odor detection threshold in humans, suggesting that allosteric modulation of odorant receptors is perceptually relevant and likely adds another layer of complexity to how odors are encoded in the peripheral olfactory system.
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Hall MJR, Ghosh D, Martín-Vega D, Clark B, Clatworthy I, Cheke RA, Rogers ME. Micro-CT visualization of a promastigote secretory gel (PSG) and parasite plug in the digestive tract of the sand fly Lutzomyia longipalpis infected with Leishmania mexicana. PLoS Negl Trop Dis 2021; 15:e0009682. [PMID: 34449767 PMCID: PMC8396784 DOI: 10.1371/journal.pntd.0009682] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Accepted: 07/27/2021] [Indexed: 01/29/2023] Open
Abstract
Leishmaniasis is a debilitating disease of the tropics, subtropics and southern Europe caused by Leishmania parasites that are transmitted during blood feeding by phlebotomine sand flies (Diptera: Psychodidae). Using non-invasive micro-computed tomography, we were able to visualize the impact of the laboratory model infection of Lutzomyia longipalpis with Leishmania mexicana and its response to a second blood meal. For the first time we were able to show in 3D the plug of promastigote secretory gel (PSG) and parasites in the distended midgut of whole infected sand flies and measure its volume in relation to that of the midgut. We were also able to measure the degree of opening of the stomodeal valve and demonstrate the extension of the PSG and parasites into the pharynx. Although our pilot study could only examine a few flies, it supports the hypothesis that a second, non-infected, blood meal enhances parasite transmission as we showed that the thoracic PSG-parasite plug in infected flies after a second blood meal was, on average, more than twice the volume of the plug in infected flies that did not have a second blood meal.
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Affiliation(s)
| | - Debashis Ghosh
- International Centre for Diarrhoeal Disease Research, Bangladesh (icddr,b), Dhaka, Bangladesh
| | - Daniel Martín-Vega
- Natural History Museum, London, United Kingdom
- Universidad de Alcalá, Alcalá de Henares (Madrid), Spain
| | - Brett Clark
- Natural History Museum, London, United Kingdom
| | | | - Robert A. Cheke
- Natural Resources Institute, University of Greenwich, Chatham Maritime, United Kingdom
| | - Matthew E. Rogers
- London School of Hygiene and Tropical Medicine, London, United Kingdom
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Mondragon-Shem K, Wongtrakul-Kish K, Kozak RP, Yan S, Wilson IBH, Paschinger K, Rogers ME, Spencer DIR, Acosta-Serrano A. Insights into the salivary N-glycome of Lutzomyia longipalpis, vector of visceral leishmaniasis. Sci Rep 2020; 10:12903. [PMID: 32737362 PMCID: PMC7395719 DOI: 10.1038/s41598-020-69753-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Accepted: 07/14/2020] [Indexed: 01/08/2023] Open
Abstract
During Leishmania transmission sand flies inoculate parasites and saliva into the skin of vertebrates. Saliva has anti-haemostatic and anti-inflammatory activities that evolved to facilitate bloodfeeding, but also modulate the host's immune responses. Sand fly salivary proteins have been extensively studied, but the nature and biological roles of protein-linked glycans remain overlooked. Here, we characterised the profile of N-glycans from the salivary glycoproteins of Lutzomyia longipalpis, vector of visceral leishmaniasis in the Americas. In silico predictions suggest half of Lu. longipalpis salivary proteins may be N-glycosylated. SDS-PAGE coupled to LC-MS analysis of sand fly saliva, before and after enzymatic deglycosylation, revealed several candidate glycoproteins. To determine the diversity of N-glycan structures in sand fly saliva, enzymatically released sugars were fluorescently tagged and analysed by HPLC, combined with highly sensitive LC-MS/MS, MALDI-TOF-MS, and exoglycosidase treatments. We found that the N-glycan composition of Lu. longipalpis saliva mostly consists of oligomannose sugars, with Man5GlcNAc2 being the most abundant, and a few hybrid-type species. Interestingly, some glycans appear modified with a group of 144 Da, whose identity has yet to be confirmed. Our work presents the first detailed structural analysis of sand fly salivary glycans.
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Affiliation(s)
- Karina Mondragon-Shem
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, L3 5QA, UK
| | - Katherine Wongtrakul-Kish
- Ludger Ltd., Culham Science Centre, Oxfordshire, OX14 3EB, UK
- Australian Research Council Centre of Excellence for Nanoscale Biophotonics, Macquarie University, Sydney, Australia
| | | | - Shi Yan
- Department of Chemistry, University of Natural Resources and Life Sciences, 1190, Vienna, Austria
- Institute of Parasitology, Department of Pathobiology, University of Veterinary Medicine, A-1210, Vienna, Austria
| | - Iain B H Wilson
- Department of Chemistry, University of Natural Resources and Life Sciences, 1190, Vienna, Austria
| | - Katharina Paschinger
- Department of Chemistry, University of Natural Resources and Life Sciences, 1190, Vienna, Austria
| | - Matthew E Rogers
- Department of Disease Control, London School of Hygiene and Tropical Medicine, London, WC1E 7HT, UK
| | | | - Alvaro Acosta-Serrano
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, L3 5QA, UK.
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Pfister P, Smith BC, Evans BJ, Brann JH, Trimmer C, Sheikh M, Arroyave R, Reddy G, Jeong HY, Raps DA, Peterlin Z, Vergassola M, Rogers ME. Odorant Receptor Inhibition Is Fundamental to Odor Encoding. Curr Biol 2020; 30:2574-2587.e6. [PMID: 32470365 DOI: 10.1016/j.cub.2020.04.086] [Citation(s) in RCA: 71] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Revised: 03/31/2020] [Accepted: 04/28/2020] [Indexed: 11/18/2022]
Abstract
Most natural odors are complex mixtures of volatile components, competing to bind odorant receptors (ORs) expressed in olfactory sensory neurons (OSNs) of the nose. To date, surprisingly little is known about how OR antagonism shapes neuronal representations in the detection layer of the olfactory system. Here, we investigated its prevalence, the degree to which it disrupts OR ensemble activity, and its conservation across phylogenetically related ORs. Calcium imaging microscopy of dissociated OSNs revealed significant inhibition, often complete attenuation, of responses to indole-a commonly occurring volatile associated with both floral and fecal odors-by a set of 36 tested odorants. To confirm an OR mechanism for the observed inhibition, we performed single-cell transcriptomics on OSNs exhibiting specific response profiles to a diagnostic panel of odorants and identified three paralogous receptors-Olfr740, Olfr741, and Olfr743-which, when tested in vitro, recapitulated OSN responses. We screened ten ORs from the Olfr740 gene family with ∼800 perfumery-related odorants spanning a range of chemical scaffolds and functional groups. Over half of these compounds (430) antagonized at least one of the ten ORs. OR activity fitted a mathematical model of competitive receptor binding and suggests normalization of OSN ensemble responses to odorant mixtures is the rule rather than the exception. In summary, we observed OR antagonism occurred frequently and in a combinatorial manner. Thus, extensive receptor-mediated computation of mixture information appears to occur in the olfactory epithelium prior to transmission of odor information to the olfactory bulb.
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Affiliation(s)
- Patrick Pfister
- Firmenich Incorporated, 250 Plainsboro Road, Plainsboro, NJ 08536, USA
| | - Benjamin C Smith
- Firmenich Incorporated, 250 Plainsboro Road, Plainsboro, NJ 08536, USA
| | - Barry J Evans
- Firmenich Incorporated, 250 Plainsboro Road, Plainsboro, NJ 08536, USA
| | - Jessica H Brann
- Firmenich Incorporated, 250 Plainsboro Road, Plainsboro, NJ 08536, USA
| | - Casey Trimmer
- Firmenich Incorporated, 250 Plainsboro Road, Plainsboro, NJ 08536, USA
| | - Mushhood Sheikh
- Firmenich Incorporated, 250 Plainsboro Road, Plainsboro, NJ 08536, USA
| | - Randy Arroyave
- Firmenich Incorporated, 250 Plainsboro Road, Plainsboro, NJ 08536, USA
| | - Gautam Reddy
- Department of Physics, UC San Diego, 9500 Gilman Dr., La Jolla, CA 92093, USA
| | - Hyo-Young Jeong
- Firmenich Incorporated, 250 Plainsboro Road, Plainsboro, NJ 08536, USA
| | - Daniel A Raps
- Firmenich Incorporated, 250 Plainsboro Road, Plainsboro, NJ 08536, USA
| | - Zita Peterlin
- Firmenich Incorporated, 250 Plainsboro Road, Plainsboro, NJ 08536, USA
| | - Massimo Vergassola
- Department of Physics, UC San Diego, 9500 Gilman Dr., La Jolla, CA 92093, USA
| | - Matthew E Rogers
- Firmenich Incorporated, 250 Plainsboro Road, Plainsboro, NJ 08536, USA.
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7
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Hall AR, Blakeman JT, Eissa AM, Chapman P, Morales-García AL, Stennett L, Martin O, Giraud E, Dockrell DH, Cameron NR, Wiese M, Yakob L, Rogers ME, Geoghegan M. Glycan–glycan interactions determine Leishmania attachment to the midgut of permissive sand fly vectors. Chem Sci 2020. [DOI: 10.1039/d0sc03298k] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Force spectroscopy was used to measure the adhesion of Leishmania to synthetic mimics of galectins on the sand fly midgut.
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8
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Langdon KW, Ebert TA, Rogers ME. Evaluating the Effect of Imidacloprid Administered in Artificial Diet on Feeding Behavior of Diaphorina citri (Hemiptera: Liviidae) Using Electropenetrography. J Econ Entomol 2019; 112:644-652. [PMID: 30602019 PMCID: PMC6427034 DOI: 10.1093/jee/toy400] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Indexed: 06/09/2023]
Abstract
The Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Liviidae) is the vector of Candidatus Liberibacter asiaticus (CLas), the presumed cause of Huanglongbing (HLB) in citrus. Management strategies were developed in Florida that used soil-applied neonicotinoids to protect young trees. Despite the implementation of intense management programs, infection spread among the most intensively managed groves. We used electopenetrography to test five imidacloprid doses (0.55, 5.5, 55, 550, and 5,500 ppm) administered in artificial diet to approximate the dosage required to reduce feeding activity and prevent salivation/ingestion activity. We failed to detect a significant effect of 0.55 ppm imidacloprid on probing behavior, pathway, or salivation/ingestion activity when compared with the untreated control. We observed a significant reduction in the number of probes and the number of pathway with both 5.5 and 55 ppm imidacloprid. We detected a significant reduction in the number of salivation/ingestion events at both 5.5 ppm and 55 ppm imidacloprid (57 and 54 percent, respectively) compared with the untreated control, and a reduction in number of sustained (>600 s) salivation/ingestion at 55 ppm. While reductions in feeding activity were apparent at dosages of at least 5.5 ppm, we were unable to prevent salivation/ingestion with dosages as high as 5,500 ppm, which is greater than what is known to occur following application in the field. While soil-applied imidacloprid may slow the spread of CLas, our findings suggest that prevention of CLas inoculation in the field is unlikely. Management strategies must be refined to prevent the spread of HLB in Florida.
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Affiliation(s)
| | - T A Ebert
- Department of Entomology and Nematology, Citrus Research and Education Center, University of Florida, Lake Alfred, FL
| | - M E Rogers
- Department of Entomology and Nematology, Citrus Research and Education Center, University of Florida, Lake Alfred, FL
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9
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Jeffries CL, Rogers ME, Walker T. Establishment of a method for Lutzomyia longipalpis sand fly embryo microinjection: The first step towards potential novel control strategies for leishmaniasis. Wellcome Open Res 2018. [DOI: 10.12688/wellcomeopenres.14555.1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Leishmaniasis is a vector-borne parasitic disease transmitted by sand flies that affects 1.3 million people across 98 countries, with limited control strategies due to the lack of an available vaccine and the emergence of insecticide resistance. Novel control strategies that are being explored for mosquito-borne diseases, such as Wolbachia bacterial inhibition of pathogens and genetically modified insects (e.g. using CRISPR-Cas9 editing), rely on the ability to consistently inject embryos of the target species. Here we present a novel method to obtain and inject preblastoderm sand fly embryos of the genus Lutzomyia (Lu.) longipalpis, the principle vector of zoonotic visceral leishmaniasis in South America. The procedures required to obtain sufficiently young Lu. longipalpis colony embryos are described alongside a microinjection technique that permits rapid injection and minimal handling of small sand fly embryos post-injection. Using a strain of Wolbachia as a ‘marker’ for successful injection, our protocol produced early generation Wolbachia transinfected Lu. longipalpis lines, demonstrating its potential as the first step for use in novel applied strategies for sand fly control.
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Jeffries CL, Rogers ME, Walker T. Establishment of a method for Lutzomyia longipalpis sand fly embryo microinjection: The first step towards potential novel control strategies for leishmaniasis. Wellcome Open Res 2018; 3:55. [PMID: 30175240 PMCID: PMC6107984 DOI: 10.12688/wellcomeopenres.14555.2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/03/2018] [Indexed: 12/31/2022] Open
Abstract
Leishmaniases is a group of vector-borne parasitic diseases transmitted by sand flies that affects 1.3 million people across 98 countries, with limited control strategies due to the lack of an available vaccine and the emergence of insecticide resistance. Novel control strategies that are being explored for mosquito-borne diseases, such as
Wolbachia bacterial inhibition of pathogens and genetically modified insects (e.g. using CRISPR-Cas9 editing), rely on the ability to consistently inject eggs of the target species. Here we present a novel method to obtain and inject preblastoderm sand fly eggs of the genus
Lutzomyia (Lu.) longipalpis, the principle vector of zoonotic visceral leishmaniasis in South America. The procedures required to obtain sufficiently young
Lu. longipalpis colony eggs are described alongside a microinjection technique that permits rapid injection and minimal handling of small sand fly eggs post-injection. Using a strain of
Wolbachia as a ‘marker’ for successful injection, our protocol produced early generation
Wolbachia transinfected
Lu. longipalpis lines, demonstrating its potential as the first step for use in novel applied strategies for sand fly control.
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Affiliation(s)
- Claire L Jeffries
- Department of Disease Control, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, WC1E 7HT, UK
| | - Matthew E Rogers
- Department of Disease Control, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, WC1E 7HT, UK
| | - Thomas Walker
- Department of Disease Control, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, WC1E 7HT, UK
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Langdon KW, Schumann R, Stelinski LL, Rogers ME. Influence of Tree Size and Application Rate on Expression of Thiamethoxam in Citrus and Its Efficacy Against Diaphorina citri (Hemiptera: Liviidae). J Econ Entomol 2018; 111:770-779. [PMID: 29471401 PMCID: PMC6019049 DOI: 10.1093/jee/toy001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Neonicotinoids are a key group of insecticides used to manage Diaphorina citri Kuwayama (Hemiptera: Liviidae), in Florida citrus. Diaphorina citri is the vector of Candidatus Liberibacter asiaticus, the presumed causal agent of huanglongbing, a worldwide disease of citrus. A two-season field study was conducted to evaluate the effect of tree size and application rate on the expression of thiamethoxam in young citrus following application to the soil. D. citri adult and nymph abundance was also correlated with thiamethoxam titer in leaves. Tree size and application rate each significantly affected thiamethoxam titer in leaf tissue. The highest mean thiamethoxam titer observed (33.39 ppm) in small trees (mean canopy volume = 0.08 m3) occurred after application of the high rate (0.74 g Platinum 75SG per tree) tested. There was a negative correlation between both nymph and adult abundance with increasing thiamethoxam titer in leaves. A concentration of 64.63 ppm thiamethoxam was required to reach a 1% probability of encountering a flush shoot with at least one adult D. citri, while 19.05 ppm was required for the same probability of encountering nymphs. The LC90 for the field population was 7.62 ppm thiamethoxam when administered through ingestion. Exposure to dosages as low as 7.62 ppm would likely result in sublethal exposure of some proportion of the population, which could exacerbate resistance development. Based on our results, subsequent work should investigate the use of neonicotinoids by foliar rather than soil application to maintain the chemical class in future insecticide management programs in Florida citrus.
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Affiliation(s)
- K W Langdon
- Department of Entomology and Nematology, Citrus Research and Education Center, University of Florida, Lake Alfred, FL, USA
| | - R Schumann
- Department of Entomology and Nematology, Citrus Research and Education Center, University of Florida, Lake Alfred, FL, USA
| | - L L Stelinski
- Department of Entomology and Nematology, Citrus Research and Education Center, University of Florida, Lake Alfred, FL, USA
| | - M E Rogers
- Department of Entomology and Nematology, Citrus Research and Education Center, University of Florida, Lake Alfred, FL, USA
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Courtenay O, Peters NC, Rogers ME, Bern C. Combining epidemiology with basic biology of sand flies, parasites, and hosts to inform leishmaniasis transmission dynamics and control. PLoS Pathog 2017; 13:e1006571. [PMID: 29049371 PMCID: PMC5648254 DOI: 10.1371/journal.ppat.1006571] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Quantitation of the nonlinear heterogeneities in Leishmania parasites, sand fly vectors, and mammalian host relationships provides insights to better understand leishmanial transmission epidemiology towards improving its control. The parasite manipulates the sand fly via production of promastigote secretory gel (PSG), leading to the “blocked sand fly” phenotype, persistent feeding attempts, and feeding on multiple hosts. PSG is injected into the mammalian host with the parasite and promotes the establishment of infection. Animal models demonstrate that sand flies with the highest parasite loads and percent metacyclic promastigotes transmit more parasites with greater frequency, resulting in higher load infections that are more likely to be both symptomatic and efficient reservoirs. The existence of mammalian and sand fly “super-spreaders” provides a biological basis for the spatial and temporal clustering of clinical leishmanial disease. Sand fly blood-feeding behavior will determine the efficacies of indoor residual spraying, topical insecticides, and bed nets. Interventions need to have sufficient coverage to include transmission hot spots, especially in the absence of field tools to assess infectiousness. Interventions that reduce sand fly densities in the absence of elimination could have negative consequences, for example, by interfering with partial immunity conferred by exposure to sand fly saliva. A deeper understanding of both sand fly and host biology and behavior is essential to ensuring effectiveness of vector interventions. We review recent research that sheds light on the quantitative biology of leishmanial transmission between sand flies and mammalian hosts and use these insights to better understand transmission, the observed epidemiology of the disease, and their implications in choice of control strategy. Using animal models, we show how the parasite-induced processes manipulate sand fly blood-feeding behavior and the infectious metacyclic dose to promote host infection and to differentially regulate the onward transmission potential of individual vectors and hosts. The existence of subpopulations of mammalian and sand fly “super-spreaders” provides a biological basis for the spatial and temporal clustering of clinical leishmanial disease. While tools are unavailable to distinguish these individuals in mixed populations, blanket interventions will be necessary to ensure inclusion of transmission hot spots. Interventions that reduce sand fly densities without elimination could interfere with vector—host dynamics and conferred partial immunity to host populations.
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Affiliation(s)
- Orin Courtenay
- School of Life Sciences, University of Warwick, Coventry, United Kingdom
- Zeeman Institute, University of Warwick, Coventry, United Kingdom
- * E-mail:
| | - Nathan C. Peters
- Snyder Institute for Chronic Diseases, University of Calgary, Calgary, Alberta, Canada
| | - Matthew E. Rogers
- Department of Disease Control, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Caryn Bern
- Department of Epidemiology and Biostatistics, School of Medicine, University of California San Francisco, San Francisco, California, United States of America
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13
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D'Hulst C, Mina RB, Gershon Z, Jamet S, Cerullo A, Tomoiaga D, Bai L, Belluscio L, Rogers ME, Sirotin Y, Feinstein P. MouSensor: A Versatile Genetic Platform to Create Super Sniffer Mice for Studying Human Odor Coding. Cell Rep 2016; 16:1115-1125. [PMID: 27396335 DOI: 10.1016/j.celrep.2016.06.047] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2015] [Revised: 05/02/2016] [Accepted: 06/09/2016] [Indexed: 12/27/2022] Open
Abstract
Typically, ∼0.1% of the total number of olfactory sensory neurons (OSNs) in the main olfactory epithelium express the same odorant receptor (OR) in a singular fashion and their axons coalesce into homotypic glomeruli in the olfactory bulb. Here, we have dramatically increased the total number of OSNs expressing specific cloned OR coding sequences by multimerizing a 21-bp sequence encompassing the predicted homeodomain binding site sequence, TAATGA, known to be essential in OR gene choice. Singular gene choice is maintained in these "MouSensors." In vivo synaptopHluorin imaging of odor-induced responses by known M71 ligands shows functional glomerular activation in an M71 MouSensor. Moreover, a behavioral avoidance task demonstrates that specific odor detection thresholds are significantly decreased in multiple transgenic lines, expressing mouse or human ORs. We have developed a versatile platform to study gene choice and axon identity, to create biosensors with great translational potential, and to finally decode human olfaction.
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Affiliation(s)
- Charlotte D'Hulst
- Department of Biological Sciences, Hunter College, City University of New York, New York, NY 10065, USA; The Graduate Center Biochemistry, Biology and Biopsychology and Behavioral Neuroscience Programs, City University of New York, New York, NY 10065, USA
| | - Raena B Mina
- Department of Biological Sciences, Hunter College, City University of New York, New York, NY 10065, USA; The Graduate Center Biochemistry, Biology and Biopsychology and Behavioral Neuroscience Programs, City University of New York, New York, NY 10065, USA
| | - Zachary Gershon
- Department of Biological Sciences, Hunter College, City University of New York, New York, NY 10065, USA; The Graduate Center Biochemistry, Biology and Biopsychology and Behavioral Neuroscience Programs, City University of New York, New York, NY 10065, USA
| | - Sophie Jamet
- Department of Biological Sciences, Hunter College, City University of New York, New York, NY 10065, USA; The Graduate Center Biochemistry, Biology and Biopsychology and Behavioral Neuroscience Programs, City University of New York, New York, NY 10065, USA
| | - Antonio Cerullo
- Department of Biological Sciences, Hunter College, City University of New York, New York, NY 10065, USA; The Graduate Center Biochemistry, Biology and Biopsychology and Behavioral Neuroscience Programs, City University of New York, New York, NY 10065, USA
| | - Delia Tomoiaga
- Department of Biological Sciences, Hunter College, City University of New York, New York, NY 10065, USA; The Graduate Center Biochemistry, Biology and Biopsychology and Behavioral Neuroscience Programs, City University of New York, New York, NY 10065, USA
| | - Li Bai
- Developmental Neural Plasticity Section, National Institute of Neurological Disorders and Stroke, NIH, Bethesda, MD 20892, USA
| | - Leonardo Belluscio
- Developmental Neural Plasticity Section, National Institute of Neurological Disorders and Stroke, NIH, Bethesda, MD 20892, USA
| | - Matthew E Rogers
- Corporate Research and Development, Firmenich Inc., Plainsboro, NJ 08536, USA
| | - Yevgeniy Sirotin
- Shelby White and Leon Levy Center for Neurobiology and Behavior, The Rockefeller University, New York, NY 10065, USA
| | - Paul Feinstein
- Department of Biological Sciences, Hunter College, City University of New York, New York, NY 10065, USA; The Graduate Center Biochemistry, Biology and Biopsychology and Behavioral Neuroscience Programs, City University of New York, New York, NY 10065, USA.
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14
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Lembong J, Sabass B, Sun B, Rogers ME, Stone HA. Mechanics regulates ATP-stimulated collective calcium response in fibroblast cells. J R Soc Interface 2016; 12:20150140. [PMID: 26063818 DOI: 10.1098/rsif.2015.0140] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Cells constantly sense their chemical and mechanical environments. We study the effect of mechanics on the ATP-induced collective calcium response of fibroblast cells in experiments that mimic various tissue environments. We find that closely packed two-dimensional cell cultures on a soft polyacrylamide gel (Young's modulus E = 690 Pa) contain more cells exhibiting calcium oscillations than cultures on a rigid substrate (E = 36 000 Pa). Calcium responses of cells on soft substrates show a slower decay of calcium level relative to those on rigid substrates. Actin enhancement and disruption experiments for the cell cultures allow us to conclude that actin filaments determine the collective Ca(2+) oscillatory behaviour in the culture. Inhibition of gap junctions results in a decrease of the oscillation period and reduced correlation of calcium responses, which suggests additional complexity of signalling upon cell-cell contact. Moreover, the frequency of calcium oscillations is independent of the rigidity of the substrate but depends on ATP concentration. We compare our results with those from similar experiments on individual cells. Overall, our observations show that collective chemical signalling in cell cultures via calcium depends critically on the mechanical environment.
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Affiliation(s)
- Josephine Lembong
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ, USA
| | - Benedikt Sabass
- Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ, USA
| | - Bo Sun
- Department of Physics, Oregon State University, Corvallis, OR, USA
| | | | - Howard A Stone
- Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ, USA
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15
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Jamet S, Bubnell J, Pfister P, Tomoiaga D, Rogers ME, Feinstein P. In Vitro Mutational Analysis of the β2 Adrenergic Receptor, an In Vivo Surrogate Odorant Receptor. PLoS One 2015; 10:e0141696. [PMID: 26513247 PMCID: PMC4626089 DOI: 10.1371/journal.pone.0141696] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2015] [Accepted: 10/12/2015] [Indexed: 11/26/2022] Open
Abstract
Many G-protein coupled receptors (GPCRs), such as odorant receptors (ORs), cannot be characterized in heterologous cells because of their difficulty in trafficking to the plasma membrane. In contrast, a surrogate OR, the GPCR mouse β2-adrenergic-receptor (mβ2AR), robustly traffics to the plasma membrane. We set out to characterize mβ2AR mutants in vitro for their eventual use in olfactory axon guidance studies. We performed an extensive mutational analysis of mβ2AR using a Green Fluorescent Protein-tagged mβ2AR (mβ2AR::GFP) to easily assess the extent of its plasma membrane localization. In order to characterize mutants for their ability to successfully transduce ligand-initiated signal cascades, we determined the half maximal effective concentrations (EC50) and maximal response to isoprenaline, a known mβ2AR agonist. Our analysis reveals that removal of amino terminal (Nt) N-glycosylation sites and the carboxy terminal (Ct) palmitoylation site of mβ2AR do not affect its plasma membrane localization. By contrast, when both the Nt and Ct of mβ2AR are replaced with those of M71 OR, plasma membrane trafficking is impaired. We further analyze three mβ2AR mutants (RDY, E268A, and C327R) used in olfactory axon guidance studies and are able to decorrelate their plasma membrane trafficking with their capacity to respond to isoprenaline. A deletion of the Ct prevents proper trafficking and abolishes activity, but plasma membrane trafficking can be selectively rescued by a Tyrosine to Alanine mutation in the highly conserved GPCR motif NPxxY. This new loss-of-function mutant argues for a model in which residues located at the end of transmembrane domain 7 can act as a retention signal when unmasked. Additionally, to our surprise, amongst our set of mutations only Ct mutations appear to lower mβ2AR EC50s revealing their critical role in G-protein coupling. We propose that an interaction between the Nt and Ct is necessary for proper folding and/or transport of GPCRs.
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MESH Headings
- Adrenergic beta-Agonists/pharmacology
- Animals
- Cell Line
- Cell Membrane/metabolism
- DNA Mutational Analysis
- Gene Expression
- Genes, Reporter
- Glycosylation
- Humans
- Isoproterenol/pharmacology
- Mice
- Mutation
- Phenotype
- Protein Binding
- Protein Interaction Domains and Motifs/genetics
- Protein Transport
- Pseudopodia/genetics
- Pseudopodia/metabolism
- Receptors, Adrenergic, beta-2/chemistry
- Receptors, Adrenergic, beta-2/genetics
- Receptors, Adrenergic, beta-2/metabolism
- Receptors, Odorant/chemistry
- Receptors, Odorant/genetics
- Receptors, Odorant/metabolism
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Affiliation(s)
- Sophie Jamet
- Department of Biological Sciences, Hunter College, CUNY, New York, New York, United States of America
| | - Jaclyn Bubnell
- Department of Biological Sciences, Hunter College, CUNY, New York, New York, United States of America
| | - Patrick Pfister
- Corporate Research and Development, Firmenich Inc., Plainsboro, New Jersey, United States of America
| | - Delia Tomoiaga
- Department of Biological Sciences, Hunter College, CUNY, New York, New York, United States of America
| | - Matthew E. Rogers
- Corporate Research and Development, Firmenich Inc., Plainsboro, New Jersey, United States of America
| | - Paul Feinstein
- Department of Biological Sciences, Hunter College, CUNY, New York, New York, United States of America
- The Graduate Center Biology Program, CUNY, New York, New York, United States of America
- The Graduate Center Behavioral and Cognitive Neuroscience Program, CUNY, New York, New York, United States of America
- * E-mail:
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16
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Lamour SD, Veselkov KA, Posma JM, Giraud E, Rogers ME, Croft S, Marchesi JR, Holmes E, Seifert K, Saric J. Metabolic, Immune, and Gut Microbial Signals Mount a Systems Response to Leishmania major Infection. J Proteome Res 2014; 14:318-29. [DOI: 10.1021/pr5008202] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- Sabrina D. Lamour
- Division
of Computational and Systems Medicine, Department of Surgery and Cancer, Imperial College London, Exhibition Road, London SW7 2AZ, United Kingdom
| | - Kirill A. Veselkov
- Division
of Computational and Systems Medicine, Department of Surgery and Cancer, Imperial College London, Exhibition Road, London SW7 2AZ, United Kingdom
| | - Joram M. Posma
- Division
of Computational and Systems Medicine, Department of Surgery and Cancer, Imperial College London, Exhibition Road, London SW7 2AZ, United Kingdom
| | - Emilie Giraud
- Department of Immunology and Infection, London School of Hygiene & Tropical Medicine, Keppel Street, London, WC1E 7HT, United Kingdom
| | - Matthew E. Rogers
- Department of Disease Control, London School of Hygiene & Tropical Medicine, Keppel Street, London, WC1E 7HT, United Kingdom
| | - Simon Croft
- Department of Immunology and Infection, London School of Hygiene & Tropical Medicine, Keppel Street, London, WC1E 7HT, United Kingdom
| | - Julian R. Marchesi
- Cardiff
School of Biosciences, Division of Microbiology, Cardiff University, Museum Avenue, Cardiff, CF10 3AT, United Kingdom
- Centre
for Digestive and Gut Health, Imperial College London, Exhibition Road, London, SW7 2AZ, United Kingdom
| | - Elaine Holmes
- Division
of Computational and Systems Medicine, Department of Surgery and Cancer, Imperial College London, Exhibition Road, London SW7 2AZ, United Kingdom
| | - Karin Seifert
- Department of Immunology and Infection, London School of Hygiene & Tropical Medicine, Keppel Street, London, WC1E 7HT, United Kingdom
| | - Jasmina Saric
- Division
of Computational and Systems Medicine, Department of Surgery and Cancer, Imperial College London, Exhibition Road, London SW7 2AZ, United Kingdom
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17
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Abstract
The odorant receptors (ORs) provide our main gateway to sensing the world of volatile chemicals. This involves a complex encoding process in which multiple ORs, each of which detects its own set of odorants, work as an ensemble to produce a distributed activation code that is presumably unique to each odorant. One marked challenge to decoding the olfactory code is OR deorphanization, the identification of a set of activating odorants for a particular receptor. Here, we survey various methods used to try to express defined ORs of interest. We also suggest strategies for selecting odorants for test panels to evaluate the functional expression of an OR. Integrating these tools, while retaining awareness of their idiosyncratic limitations, can provide a multi-tiered approach to OR deorphanization, spanning the initial discovery of a ligand to vetting that ligand in a physiologically relevant setting.
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Affiliation(s)
- Zita Peterlin
- Corporate Research and Development, Firmenich Incorporated, Plainsboro, NJ 08536
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18
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Abstract
We describe a microfluidic system for generating a sequence of liquid droplets of multiple concentrations in a single experimental condition. The series of final droplets has the combination of the compositions varying periodically, with polydispersity of the size less than 8%. By utilizing the design of the microchannel geometry and the passive control of three immiscible fluids (oil, water, and air) including generation, breakup, separation and coalescence of droplets, we can change the system to generate diverse sets of combination of materials. The device can be used for testing different concentration of materials in picoliter volumes and developing a new way to deliver dynamic signals of chemicals with microfluidics.
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Affiliation(s)
- Eujin Um
- Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ 08544, USA.
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19
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Bubnell J, Pfister P, Sapar ML, Rogers ME, Feinstein P. β2 adrenergic receptor fluorescent protein fusions traffic to the plasma membrane and retain functionality. PLoS One 2013; 8:e74941. [PMID: 24086401 PMCID: PMC3781101 DOI: 10.1371/journal.pone.0074941] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2013] [Accepted: 08/07/2013] [Indexed: 11/29/2022] Open
Abstract
Green fluorescent protein (GFP) has proven useful for the study of protein interactions and dynamics for the last twenty years. A variety of new fluorescent proteins have been developed that expand the use of available excitation spectra. We have undertaken an analysis of seven of the most useful fluorescent proteins (XFPs), Cerulean (and mCerulean3), Teal, GFP, Venus, mCherry and TagRFP657, as fusions to the archetypal G-protein coupled receptor, the β2 adrenergic receptor (β2AR). We have characterized these β2AR::XFP fusions in respect to membrane trafficking and G-protein activation. We noticed that in the mouse neural cell line, OP 6, that membrane bound β2AR::XFP fusions robustly localized in the filopodia identical to gap::XFP fusions. All β2AR::XFP fusions show responses indistinguishable from each other and the non-fused form after isoprenaline exposure. Our results provide a platform by which G-protein coupled receptors can be dissected for their functionality.
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Affiliation(s)
- Jaclyn Bubnell
- Department of Biological Sciences, Hunter College and The Graduate Center Biochemistry, Biology and Biopsychology and Behavioral Neuroscience Programs, CUNY, New York, New York, United States of America
| | - Patrick Pfister
- Corporate Research and Development, Firmenich Inc., Plainsboro, New Jersey, United States of America
| | - Maria L. Sapar
- Department of Biological Sciences, Hunter College and The Graduate Center Biochemistry, Biology and Biopsychology and Behavioral Neuroscience Programs, CUNY, New York, New York, United States of America
| | - Matthew E. Rogers
- Corporate Research and Development, Firmenich Inc., Plainsboro, New Jersey, United States of America
| | - Paul Feinstein
- Department of Biological Sciences, Hunter College and The Graduate Center Biochemistry, Biology and Biopsychology and Behavioral Neuroscience Programs, CUNY, New York, New York, United States of America
- * E-mail:
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20
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Serikawa RH, Backus EA, Rogers ME. Effects of soil-applied imidacloprid on Asian citrus psyllid (Hemiptera: Psyllidae) feeding behavior. J Econ Entomol 2012; 105:1492-502. [PMID: 23156142 DOI: 10.1603/ec11211] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
The Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Psyllidae), is one of the most important pests of citrus (Citrus spp.) because of its status as a vector of Candidatus Liberibacter asiaticus (Las), the bacterium associated with citrus greening disease. The use of insecticides for vector control is the primary method of managing the spread of this pathogen. Imidacloprid is an insecticide commonly applied to the root zone of young citrus trees to provide systemic protection from pests. The effects of imidacloprid on feeding behavior of D. citri have not been studied in much detail. The purpose of this study was to examine the effects of imidacloprid application on feeding behavior of D. citri and to determine whether use of this systemic insecticide could have any effect on pathogen transmission by D. citri. A direct current electrical penetration graph monitor was used to record D. citri feeding behaviors for 12-h periods on mature and young leaves of imidacloprid-treated and -untreated citrus seedlings. Overall, compared with untreated plants, the feeding behavior of D. citri was disrupted on imidacloprid-treated plants via reduction in the number of probes, as well as durations of average probes, initial stylet contact with phloem, phloem salivation, and phloem ingestion. The results of this study demonstrate that soil applications of imidacloprid can reduce the probability of citrus plants becoming inoculated with Las through a reduction in the number and duration of phloem salivation events by D. citri. Furthermore, Las acquisition from infected citrus is greatly reduced as a result of decreased phloem ingestion by D. citri on imidacloprid-treated plants.
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Affiliation(s)
- R H Serikawa
- Department of Entomology and Nematology, Citrus Research and Education Center, University of Florida, 700 Experiment Station Rd., Lake Alfred, FL 33850, USA
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21
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Rogers ME. The role of leishmania proteophosphoglycans in sand fly transmission and infection of the Mammalian host. Front Microbiol 2012; 3:223. [PMID: 22754550 PMCID: PMC3384971 DOI: 10.3389/fmicb.2012.00223] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2012] [Accepted: 05/31/2012] [Indexed: 11/17/2022] Open
Abstract
Leishmania are transmitted by the bite of their sand fly vector and this has a significant influence on the virulence of the resulting infection. From our studies into the interaction between parasite, vector, and host we have uncovered an important missing ingredient during Leishmania transmission. Leishmania actively adapt their sand fly hosts into efficient vectors by secreting Promastigote Secretory Gel (PSG), a proteophosphoglycan (PPG)-rich, mucin-like gel which accumulates in sand fly gut and mouthparts. This has the effect of blocking the fly, such that during bloodfeeding both parasites and gel are co-transmitted in an act of regurgitation. We are discovering that this has further implications for the mammalian infection, again, in favor of the parasite. Experimentally, PSG exacerbates cutaneous and visceral leishmaniasis and can promote the chronicity of Leishmania infection, even in mouse strains normally capable of controlling leishmaniasis. The underlying mechanism of PSG's action is a major focus of our ongoing work. This review aims to synthesize what is known about the role and action of PSG and its constituent proteophosphoglycans, for parasite colonization of the sand fly, transmission, and mammalian infection. Lastly, we discuss potential exploitation of this important vector-transmitted product and future avenues of research.
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Affiliation(s)
- Matthew E. Rogers
- Faculty of Infectious Tropical Diseases, Department of Immunology and Infection, London School of Hygiene and Tropical MedicineLondon, UK
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22
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Pelz-Stelinski KS, Brlansky RH, Ebert TA, Rogers ME. Transmission parameters for Candidatus liberibacter asiaticus by Asian citrus psyllid (Hemiptera: Psyllidae). J Econ Entomol 2010; 103:1531-41. [PMID: 21061950 DOI: 10.1603/ec10123] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
The purpose of this investigation was to evaluate acquisition and inoculation (together, transmission) efficiency of Candidatus Liberibacter asiaticus (Las), the pathogen associated with citrus huanglongbing (HLB) by the Asian citrus psyllid, Diaphorina citri (Kuwayama) (Hemiptera: Psyllidae). In laboratory studies, nymphs reared on Las infected plants were more likely to acquire the bacterium than adults. Acquisition by nymphs ranged from 60 to 100%, whereas acquisition by adults only reached 40% after 5 wk of feeding on Las-infected plants. Similar rates of pathogen acquisition by psyllids after nymphal and adult feeding were observed in the field. Transmission of Las from parent to offspring (transovarial) occurred at a rate of 2-6%. One year after psyllid inoculations, successful transmission by individual D. citri ranged from 4 to 10%, whereas groups of 100 or more D. citri transmitted the pathogen at a rate of approximately 88%. In addition, the proportion of Las-positive adult psyllids, determined using quantitative real-time polymerase chain reaction, decreased over time when held on healthy plants. Due to the low rate of pathogen acquisition and long time period required for successful inoculation by adult D. citri, experiments designed to determine the latent period required for replication and successful inoculation of Las by D. citri did not result in Las-infected plants after >1 yr of incubation after inoculation. Collectively, these results indicate that adult D. citri which acquire the HLB pathogen as adults are poor vectors of the pathogen compared with adults that acquired the pathogen as nymphs.
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Affiliation(s)
- K S Pelz-Stelinski
- Department of Entomology and Nematology, Citrus Research and Education Center, University of Florida, Lake Alfred, FL 33850, USA.
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23
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Clements MF, Gidwani K, Kumar R, Hostomska J, Dinesh DS, Kumar V, Das P, Müller I, Hamilton G, Volfova V, Boelaert M, Das M, Rijal S, Picado A, Volf P, Sundar S, Davies CR, Rogers ME. Measurement of recent exposure to Phlebotomus argentipes, the vector of Indian visceral Leishmaniasis, by using human antibody responses to sand fly saliva. Am J Trop Med Hyg 2010; 82:801-7. [PMID: 20439958 PMCID: PMC2861389 DOI: 10.4269/ajtmh.2010.09-0336] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Antibody (IgG) responses to the saliva of Phlebotomus argentipes were investigated using serum samples from regions of India endemic and non-endemic for visceral leishmaniasis (VL). By pre-adsorbing the sera against the saliva of the competing human-biting but non-VL vector P. papatasi, we significantly improved the specificity of a P. argentipes saliva enzyme-linked immunosorbent assay. Using this method, we observed a statistically significant correlation between antibodies to P. argenitpes saliva and the average indoor density of female sand flies. Additionally, the method was able to detect recent changes in vector exposure when sera from VL patients were assayed before, during, and after hospitalization and protected from sand fly bites under untreated bed nets. Collectively, these results highlight the utility of antibodies to P. argentipes saliva as an important tool to evaluate VL vector control programs.
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24
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Modolell M, Choi BS, Ryan RO, Hancock M, Titus RG, Abebe T, Hailu A, Müller I, Rogers ME, Bangham CRM, Munder M, Kropf P. Local suppression of T cell responses by arginase-induced L-arginine depletion in nonhealing leishmaniasis. PLoS Negl Trop Dis 2009; 3:e480. [PMID: 19597544 PMCID: PMC2703824 DOI: 10.1371/journal.pntd.0000480] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2009] [Accepted: 06/05/2009] [Indexed: 11/19/2022] Open
Abstract
The balance between T helper (Th) 1 and Th2 cell responses is a major determinant of the outcome of experimental leishmaniasis, but polarized Th1 or Th2 responses are not sufficient to account for healing or nonhealing. Here we show that high arginase activity, a hallmark of nonhealing disease, is primarily expressed locally at the site of pathology. The high arginase activity causes local depletion of L-arginine, which impairs the capacity of T cells in the lesion to proliferate and to produce interferon-γ, while T cells in the local draining lymph nodes respond normally. Healing, induced by chemotherapy, resulted in control of arginase activity and reversal of local immunosuppression. Moreover, competitive inhibition of arginase as well as supplementation with L-arginine restored T cell effector functions and reduced pathology and parasite growth at the site of lesions. These results demonstrate that in nonhealing leishmaniasis, arginase-induced L-arginine depletion results in impaired T cell responses. Our results identify a novel mechanism in leishmaniasis that contributes to the failure to heal persistent lesions and suggest new approaches to therapy. Leishmania parasites are obligate intracellular pathogens that predominantly invade macrophages. Instruction of macrophages by T cell-derived signals is required to control parasite growth. Here we show that arginase, an enzyme induced in Leishmania-infected macrophages, is highly expressed at the site of pathology in nonhealing lesions and causes local depletion of L-arginine, an amino acid that is essential for efficient T cell responses. This local reduction in L-arginine impairs the capacity of T cells in the lesion to proliferate and to produce interferon-γ, one of the signals required for parasite killing. Cure of Leishmania infection by drug treatment is accompanied by a reduction in arginase activity and restoration of T cell effector functions. Furthermore, inhibition of arginase, as well as injection of L-arginine, reverses immunosuppression and results in more efficient control of parasite replication. Our results identify a novel mechanism accounting for ineffective T cell responses in nonhealing leishmaniasis.
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Affiliation(s)
- Manuel Modolell
- Department of Cellular Immunology, Max-Planck-Institute for Immunobiology, Freiburg, Germany
| | - Beak-San Choi
- Department of Immunology, Faculty of Medicine, Imperial College London, London, United Kingdom
| | - Robert O. Ryan
- Lipid Biology in Health and Disease Research Group, Children's Hospital Oakland Research Institute, Oakland, California, United States of America
| | - Maggie Hancock
- Imperial College Healthcare NHS Trust, Chelsea and Westminster Hospital, London, United Kingdom
| | - Richard G. Titus
- Microbiology, Immunology, and Pathology Department, Colorado State University, Fort Collins, Colorado, United States of America
| | - Tamrat Abebe
- Department of Microbiology, Parasitology and Immunology, University of Addis Ababa, Addis Ababa, Ethiopia
| | - Asrat Hailu
- Department of Microbiology, Parasitology and Immunology, University of Addis Ababa, Addis Ababa, Ethiopia
| | - Ingrid Müller
- Department of Immunology, Faculty of Medicine, Imperial College London, London, United Kingdom
| | - Matthew E. Rogers
- Department of Immunology, Faculty of Medicine, Imperial College London, London, United Kingdom
| | - Charles R. M. Bangham
- Department of Immunology, Faculty of Medicine, Imperial College London, London, United Kingdom
| | - Markus Munder
- Department of Hematology, Oncology, and Rheumatology, University Hospital Heidelberg, Heidelberg, Germany
| | - Pascale Kropf
- Department of Immunology, Faculty of Medicine, Imperial College London, London, United Kingdom
- * E-mail:
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25
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Ranasinghe S, Rogers ME, Hamilton JG, Bates PA, Maingon RD. A real-time PCR assay to estimate Leishmania chagasi load in its natural sand fly vector Lutzomyia longipalpis. Trans R Soc Trop Med Hyg 2008; 102:875-82. [PMID: 18501935 PMCID: PMC2678673 DOI: 10.1016/j.trstmh.2008.04.003] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2007] [Revised: 04/01/2008] [Accepted: 04/01/2008] [Indexed: 11/19/2022] Open
Abstract
Leishmania chagasi, transmitted mainly by Lutzomyia longipalpis sand flies, causes visceral leishmaniasis and atypical cutaneous leishmaniasis in Latin America. Successful vector control depends upon determining vectorial capacity and understanding Leishmania transmission by sand flies. As microscopic detection of Leishmania in dissected sand fly guts is laborious and time-consuming, highly specific, sensitive, rapid and robust Leishmania PCR assays have attracted epidemiologists' attention. Real-time PCR is faster than qualitative PCR and yields quantitative data amenable to statistical analyses. A highly reproducible Leishmania DNA polymerase gene-based TaqMan real-time PCR assay was adapted to quantify Leishmania in sand flies, showing intra-assay and inter-assay coefficient variations lower than 1 and 1.7%, respectively, and sensitivity to 10 pg Leishmania DNA ( approximately 120 parasites) in as much as 100 ng sand fly DNA. Data obtained for experimentally infected sand flies yielded parasite loads within the range of counts obtained by microscopy for the same sand fly cohort or that were around five times higher than microscopy counts, depending on the method used for data analysis. These results highlight the potential of quantitative PCR for Leishmania transmission studies, and the need to understand factors affecting its sensitivity and specificity.
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Affiliation(s)
- Shalindra Ranasinghe
- Centre for Applied Entomology and Parasitology, Institute of Science and Technology in Medicine, Keele University, Staffordshire ST5 5BG, UK
- Department of Parasitology, Faculty of Medical Sciences, University Sri Jayewardenepura, Gangodawila, Nugegoda, Sri Lanka
| | - Matthew E. Rogers
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK
- Department of Immunology, Imperial College of Science, Technology and Medicine, London, Norfolk Place, London W2 1PG, UK
| | - James G.C. Hamilton
- Centre for Applied Entomology and Parasitology, Institute of Science and Technology in Medicine, Keele University, Staffordshire ST5 5BG, UK
| | - Paul A. Bates
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK
| | - Rhayza D.C. Maingon
- Centre for Applied Entomology and Parasitology, Institute of Science and Technology in Medicine, Keele University, Staffordshire ST5 5BG, UK
- Corresponding author. Tel.: +44 1782 584 219; fax: +44 1782 583 516.
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Rogers ME, Hajmová M, Joshi MB, Sadlova J, Dwyer DM, Volf P, Bates PA. Leishmania chitinase facilitates colonization of sand fly vectors and enhances transmission to mice. Cell Microbiol 2008; 10:1363-72. [PMID: 18284631 PMCID: PMC2408650 DOI: 10.1111/j.1462-5822.2008.01132.x] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
Chitinases of trypanosomatid parasites have been proposed to fulfil various roles in their blood-feeding arthropod vectors but so far none have been directly tested using a molecular approach. We characterized the ability of Leishmania mexicana episomally transfected with LmexCht1 (the L. mexicana chitinase gene) to survive and grow within the permissive sand fly vector, Lutzomyia longipalpis. Compared with control plasmid transfectants, the overexpression of chitinase was found to increase the average number of parasites per sand fly and accelerate the escape of parasites from the peritrophic matrix-enclosed blood meal as revealed by earlier arrival at the stomodeal valve. Such flies also exhibited increased damage to the structure of the stomodeal valve, which may facilitate transmission by regurgitation. When exposed individually to BALB/c mice, those flies with chitinase-overexpressing parasites spent on average 2.4–2.5 times longer in contact with their host during feeding, compared with flies with control infections. Furthermore, the lesions that resulted from these single fly bite infections were both significantly larger and with higher final parasite burdens than controls. These data show that chitinase is a multifunctional virulence factor for L. mexicana which assists its survival in Lu. longipalpis. Specifically, this enzyme enables the parasites to colonize the anterior midgut of the sand fly more quickly, modify the sand fly stomodeal valve and affect its blood feeding, all of which combine to enhance transmission.
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Affiliation(s)
- Matthew E Rogers
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK.
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Li Z, Rogers ME. Update on the distribution of the Andean cat Oreailurus jacobita and the pampas cat Lynchailurus colocolo in Peru. ENDANGER SPECIES RES 2007. [DOI: 10.3354/esr00055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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Abstract
In nature the prevalence of Leishmania infection in whole sand fly populations can be very low (<0.1%), even in areas of endemicity and high transmission. It has long since been assumed that the protozoan parasite Leishmania can manipulate the feeding behavior of its sand fly vector, thus enhancing transmission efficiency, but neither the way in which it does so nor the mechanisms behind such manipulation have been described. A key feature of parasite development in the sand fly gut is the secretion of a gel-like plug composed of filamentous proteophosphoglycan. Using both experimental and natural parasite–sand fly combinations we show that secretion of this gel is accompanied by differentiation of mammal-infective transmission stages. Further, Leishmania infection specifically causes an increase in vector biting persistence on mice (re-feeding after interruption) and also promotes feeding on multiple hosts. Both of these aspects of vector behavior were found to be finely tuned to the differentiation of parasite transmission stages in the sand fly gut. By experimentally accelerating the development rate of the parasites, we showed that Leishmania can optimize its transmission by inducing increased biting persistence only when infective stages are present. This crucial adaptive manipulation resulted in enhanced infection of experimental hosts. Thus, we demonstrate that behavioral manipulation of the infected vector provides a selective advantage to the parasite by significantly increasing transmission. Leishmaniasis is a human parasitic disease that can result in destructive skin lesions or sometimes in fatal visceral involvement if left untreated. Infections are acquired via the bites of female sand flies, small blood-feeding insects. In this experimental study using mice, we show that Leishmania parasites can manipulate the behavior of sand flies so that infected flies become more tenacious, returning to feed if interrupted more readily and delivering more bites than uninfected flies. This change in behavior occurs only when the parasites have become infective to humans and are ready for transmission. At the same time, the parasites in the sand fly secrete a viscous gel that blocks up the gut and mouthparts and interferes with feeding. The result of this manipulation is an increase in the severity of disease and number of infections. These findings help us to better understand how human infection occurs, which is important when trying to devise ways of controlling this disease. It is currently estimated that at least 12 million people have leishmaniasis, with 2 million new infections every year.
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Affiliation(s)
- Matthew E Rogers
- Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Paul A Bates
- Liverpool School of Tropical Medicine, Liverpool, United Kingdom
- * To whom correspondence should be addressed. E-mail:
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Vesper SJ, Haugland RA, Rogers ME, Neely AN. Opportunistic Aspergillus pathogens measured in home and hospital tap water by quantitative PCR (QPCR). J Water Health 2007; 5:427-31. [PMID: 17878557 DOI: 10.2166/wh.2007.038] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Opportunistic fungal pathogens are a concern because of the increasing number of immunocompromised patients. The goal of this research was to test a simple extraction method and rapid quantitative PCR (QPCR) measurement of the occurrence of potential pathogens, Aspergillus fumigatus, A. flavus, A. terreus and A. niger, in home tap water and a hospital water supply. Water samples were taken from the kitchen tap in the homes of 60 patients who were diagnosed with legionellosis. Water samples were also taken from three locations in a hospital that generated all of its hot water by flash heating. Opportunistic infectious agents Aspergillus fumigatus, A. flavus, A. terreus and A. niger were measured using QPCR. Aspergillus terreus DNA was found in 16.7% and A. fumigatus DNA in 1.7% of the samples taken from the kitchen tap. None of the Aspergillus species were found in any of the hospital water samples.The development of a simple DNA extraction method along with QPCR analysis is suitable for rapid screening of tap water for opportunistic fungal pathogens. This simple method can be used to obtain pathogen occurrence results in about 3 h, instead of waiting days to weeks for culture data. Obtaining pathogen occurrence data in a timely manner could promote the elimination of the pathogens from the water supply of immunocompromised patients.
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Affiliation(s)
- S J Vesper
- National Exposure Research Laboratory, US Environmental Protection Agency, Cincinnati, OH 45216, USA.
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Dillon RJ, Ivens AC, Churcher C, Holroyd N, Quail MA, Rogers ME, Soares MB, Bonaldo MF, Casavant TL, Lehane MJ, Bates PA. Analysis of ESTs from Lutzomyia longipalpis sand flies and their contribution toward understanding the insect-parasite relationship. Genomics 2006; 88:831-840. [PMID: 16887324 PMCID: PMC2675706 DOI: 10.1016/j.ygeno.2006.06.011] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2006] [Revised: 06/16/2006] [Accepted: 06/20/2006] [Indexed: 11/30/2022]
Abstract
An expressed sequence tag library has been generated from a sand fly vector of visceral leishmaniasis, Lutzomyia longipalpis. A normalized cDNA library was constructed from whole adults and 16,608 clones were sequenced from both ends and assembled into 10,203 contigs and singlets. Of these 58% showed significant similarity to known genes from other organisms, < 4% were identical to described sand fly genes, and 42% had no match to any database sequence. Our analyses revealed putative proteins involved in the barrier function of the gut (peritrophins, microvillar proteins, glutamine synthase), digestive physiology (secreted and membrane-anchored hydrolytic enzymes), and the immune response (gram-negative binding proteins, thioester proteins, scavenger receptors, galectins, signaling pathway factors, caspases, serpins, and peroxidases). Sequence analysis of this transcriptome dataset has provided new insights into genes that might be associated with the response of the vector to the development of Leishmania.
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Affiliation(s)
- Rod J Dillon
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK.
| | - Al C Ivens
- The Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, UK
| | - Carol Churcher
- The Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, UK
| | - Nancy Holroyd
- The Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, UK
| | - Michael A Quail
- The Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, UK
| | - Matthew E Rogers
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK
| | - M Bento Soares
- Children's Memorial Research Center and Northwestern University, Chicago, IL 60611, USA
| | - Maria F Bonaldo
- Children's Memorial Research Center and Northwestern University, Chicago, IL 60611, USA
| | - Thomas L Casavant
- Department of Electrical and Computer Engineering, University of Iowa, Iowa City, IA 52242, USA
| | - Mike J Lehane
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK
| | - Paul A Bates
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK
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Rogers ME, Sizova OV, Ferguson MAJ, Nikolaev AV, Bates PA. Synthetic glycovaccine protects against the bite of leishmania-infected sand flies. J Infect Dis 2006; 194:512-8. [PMID: 16845636 PMCID: PMC2839923 DOI: 10.1086/505584] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2006] [Accepted: 03/22/2006] [Indexed: 01/21/2023] Open
Abstract
Leishmaniasis is a vectorborne disease transmitted to human and other mammalian hosts by sand fly bite. In the present study, we show that immunization with Leishmania mexicana promastigote secretory gel (PSG) or with a chemically defined synthetic glycovaccine containing the glycans found in L. mexicana PSG can provide significant protection against challenge by the bite of infected sand flies. Only the glycan from L. mexicana was protective; those from other species did not protect against L. mexicana infection. Furthermore, neither PSG nor the glycovaccine protected against artificial needle challenge, which is traditionally used in antileishmanial vaccine development. Conversely, an antigen preparation that was effective against needle challenge offered no protection against sand fly bite. These findings provide a new target for Leishmania vaccine development and demonstrate the critical role that the vector plays in the evaluation of candidate vaccines for leishmaniasis and other vectorborne diseases.
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Affiliation(s)
- Matthew E Rogers
- Liverpool School of Tropical Medicine, University of Liverpool, Pembroke Place, Liverpool L3 5QA, United Kingdom
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Poot J, Rogers ME, Bates PA, Vermeulen A. Detailed analysis of an experimental challenge model for Leishmania infantum (JPC strain) in dogs. Vet Parasitol 2005; 130:41-53. [PMID: 15893068 DOI: 10.1016/j.vetpar.2005.03.002] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2004] [Revised: 02/17/2005] [Accepted: 03/09/2005] [Indexed: 10/25/2022]
Abstract
In this study, disease progression after intravenous or subdermal infection of dogs with Leishmania infantum JPC strain was monitored. A challenge performed on 14 dogs via the intravenous route with 5 x 10(7) stationary phase promastigotes of the L. infantum JPC strain was 100% successful. During a follow up period of 1.5 years, several parameters were evaluated in order to find the most reliable disease markers. Parasite detection by culture and histology were found to be very sensitive (100%). Additionally, regular physical examination, serology and serum gamma-globulin levels were found to be useful parameters in the evaluation of disease severity and are recommended for inclusion in vaccination-challenge experiments. Although this intravenous challenge model has practical limitations, the data set confirms it is the best experimental model currently available for vaccine development. Two intravenously infected dogs were treated with corticosteroids for 5 months. This treatment was shown to enhance all aspects of a Leishmania infection. Five more dogs were infected by sub-dermal injection of promastigotes mixed with a proteophosphoglycan-matrix (PSG) secreted by Leishmania that assists in transmission and infection by sand fly bite. The resulting parasite burdens were low and the animals remained asymptomatic during a 2-year follow up period. However, this procedure did result in infection in 80% of the dogs and is appealing for future development as a natural challenge model in vaccine development.
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Affiliation(s)
- Jacqueline Poot
- Intervet International B.V., Parasitology R&D, Wim de Körverstraat 35, 5831 AN Boxmeer, The Netherlands.
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Joshi MB, Rogers ME, Shakarian AM, Yamage M, Al-Harthi SA, Bates PA, Dwyer DM. Molecular characterization, expression, and in vivo analysis of LmexCht1: the chitinase of the human pathogen, Leishmania mexicana. J Biol Chem 2004; 280:3847-61. [PMID: 15561707 PMCID: PMC2839926 DOI: 10.1074/jbc.m412299200] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Chitinases have been implicated to be of importance in the life cycle development and transmission of a variety of parasitic organisms. Using a molecular approach, we identified and characterized the structure of a single copy LmexCht1-chitinase gene from the primitive trypanosomatid pathogen of humans, Leishmania mexicana. The LmexCht1 encodes an approximately 50 kDa protein, with well conserved substrate binding and catalytic domains characteristic of members of the chitinase-18 protein family. Further, we showed that LmexCht1 mRNA is constitutively expressed by both the insect vector (i.e. promastigote) and mammalian (i.e. amastigote) life cycle developmental forms of this protozoan parasite. Interestingly, however, amastigotes were found to secrete/release approximately >2-4-fold higher levels of chitinase activity during their growth in vitro than promastigotes. Moreover, a homologous episomal expression system was devised and used to express an epitope-tagged LmexCht1 chimeric construct in these parasites. Expression of the LmexCht1 chimera was verified in these transfectants by reverse transcription-PCR, Western blots, and indirect immunofluorescence analyses. Further, results of coupled immunoprecipitation/enzyme activity experiments demonstrated that the LmexCht1 chimeric protein was secreted/released by these transfected L. mexicana parasites and that it possessed functional chitinase enzyme activity. Such transfectants were also evaluated for their infectivity both in human macrophages in vitro and in two different strains of mice. Results of those experiments demonstrated that the LmexCht1 transfectants survived significantly better in human macrophages and also produced significantly larger lesions in mice than control parasites. Taken together, our results indicate that the LmexCht1-chimera afforded a definitive survival advantage to the parasite within these mammalian hosts. Thus, the LmexCht1 could potentially represent a new virulence determinant in the mammalian phase of this important human pathogen.
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Affiliation(s)
- Manju B. Joshi
- Cell Biology Section, Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892-0425, USA
| | - Matthew E. Rogers
- Molecular and Biochemical Parasitology Group, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK
| | - Alison M. Shakarian
- Cell Biology Section, Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892-0425, USA
| | - Mat Yamage
- Cell Biology Section, Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892-0425, USA
| | - Saeed A. Al-Harthi
- Molecular and Biochemical Parasitology Group, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK
| | - Paul A. Bates
- Molecular and Biochemical Parasitology Group, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK
| | - Dennis M. Dwyer
- Cell Biology Section, Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892-0425, USA
- Corresponding Author: Phone: (301) 496-5969; Fax: (301) 402-0079;
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Abstract
Leishmania alternates between two main morphological forms in its life cycle: intracellular amastigotes in the mammalian host and motile promastigotes in the sandfly vector. Several different forms of promastigote can be recognised in sandfly infections. The first promastigote forms, which are found in the sandfly in the bloodmeal phase, are multiplicative procyclic promastigotes. These differentiate into nectomonad promastigotes, which are a non-dividing migratory stage moving from the posterior to the anterior midgut. When nectomonad promastigotes arrive at the anterior midgut they differentiate into leptomonad forms, a newly named life cycle stage, which resume replication. Leptomonad promastigotes, which are found in the anterior midgut, are the developmental precursors of the metacyclic promastigotes, the mammal-infective stages. Leptomonad forms also produce promastigote secretory gel, a substance that plays a key role in transmission by forming a physical obstruction in the gut, forcing the sandfly to regurgitate metacyclic promastigotes during bloodfeeding.
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Affiliation(s)
- P A Bates
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK.
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Rogers ME, Ilg T, Nikolaev AV, Ferguson MAJ, Bates PA. Transmission of cutaneous leishmaniasis by sand flies is enhanced by regurgitation of fPPG. Nature 2004; 430:463-7. [PMID: 15269771 PMCID: PMC2835460 DOI: 10.1038/nature02675] [Citation(s) in RCA: 203] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2004] [Accepted: 05/18/2004] [Indexed: 11/09/2022]
Abstract
Sand flies are the exclusive vectors of the protozoan parasite Leishmania, but the mechanism of transmission by fly bite has not been determined nor incorporated into experimental models of infection. In sand flies with mature Leishmania infections the anterior midgut is blocked by a gel of parasite origin, the promastigote secretory gel. Here we analyse the inocula from Leishmania mexicana-infected Lutzomyia longipalpis sand flies. Analysis revealed the size of the infectious dose, the underlying mechanism of parasite delivery by regurgitation, and the novel contribution made to infection by filamentous proteophosphoglycan (fPPG), a component of promastigote secretory gel found to accompany the parasites during transmission. Collectively these results have important implications for understanding the relationship between the parasite and its vector, the pathology of cutaneous leishmaniasis in humans and also the development of effective vaccines and drugs. These findings emphasize that to fully understand transmission of vector-borne diseases the interaction between the parasite, its vector and the mammalian host must be considered together.
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Affiliation(s)
- Matthew E Rogers
- Liverpool School of Tropical Medicine, University of Liverpool, Pembroke Place, Liverpool L3 5QA, UK
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Abstract
The life cycle of Leishmania alternates between two main morphological forms: intracellular amastigotes in the mammalian host and motile promastigotes in the sand fly vector. Several different forms of promastigote have been described in sandfly infections, the best known of these being metacyclic promastigotes, the mammal-infective stages. Here we provide evidence that for Leishmania (Leishmania) mexicana and Leishmania (Leishmania) infantum (syn. chagasi) there are two separate, consecutive growth cycles during development in Lutzomyia longipalpis sand flies involving four distinct life cycle stages. The first growth cycle is initiated by procyclic promastigotes, which divide in the bloodmeal in the abdominal midgut and subsequently give rise to non-dividing nectomonad promastigotes. Nectomonad forms are responsible for anterior migration of the infection and in turn transform into leptomonad promastigotes that initiate a second growth cycle in the anterior midgut. Subsequently, leptomonad promastigotes differentiate into non-dividing metacyclic promastigotes in preparation for transmission to a mammalian host. Differences in timing, prevalence and persistence of the four promastigote stages were observed between L. mexicana and L. infantum in vivo, which were reproduced in cultures initiated with lesion amastigotes, indicating that development is to some extent governed by a programmed series of events. A new scheme for the life cycle in the subgenus Leishmania (Leishmania) is proposed that incorporates these findings.
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Affiliation(s)
| | | | - Paul A. Bates
- Corresponding author: Liverpool School of Tropical Medicine Pembroke Place Liverpool L3 5QA UK Tel: +44 151 705 3314 Fax: +44 151 705 3371
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Abstract
PURPOSE To determine the effectiveness of an intervention programme utilizing modules specifically designed to challenge mobility in older adults. METHOD Twelve older adults aged 79-90 years (84.3+/-3.2; mean+/-SD) living in a retirement community participated in a 10-week (3 sessions per week, 50 minutes per session) training programme. Performance on a modular course, comprised of nine stations representing common environmental conditions, provided information about dynamic balance and mobility before and after the intervention programme. Stations consisted of walking across carpet and foam pathways, walking up and down ramps and stairs, walking through a slalom course of eight plastic cones, and stepping over foam props. Performance on the mobility course was videotaped to determine the time to complete each station. The training intervention consisted of performing sections of the mobility course and standing on foam pads with the eyes open or closed. RESULTS Using the Bonferroni-adjusted level of significance for multiple comparisons (p+/-0.005), paired sample t-tests indicated significant improvement for total time to complete the course (pre=100.9+/-40.5 s, post=79.6+/-40.3 s) and for all individual stations except stepping over props. CONCLUSIONS These results indicate that an intervention programme utilizing functionally-oriented modules can improve mobility in older adults.
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Affiliation(s)
- M E Rogers
- Department of Kinesiology and Sport Studies, Wichita State University, USA.
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Rogers ME, Chance ML, Bates PA. The role of promastigote secretory gel in the origin and transmission of the infective stage of Leishmania mexicana by the sandfly Lutzomyia longipalpis. Parasitology 2002; 124:495-507. [PMID: 12049412 DOI: 10.1017/s0031182002001439] [Citation(s) in RCA: 137] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Transmission of leishmaniasis is effected by a specific developmental stage, the metacyclic promastigote. The precursors of metacyclic promastigotes were a distinct subpopulation of parasites, identified for the first time as a new stage in the life-cycle and named leptomonad promastigotes. Microdissection of infected sandflies into 4 midgut regions and foregut allowed precursor-product relationships to be established for amastigote-procyclic promastigote, procyclic-nectomonad promastigote, nectomonad-leptomonad promastigote and leptomonad-metacyclic promastigote developmental switches. Metacyclic promastigotes occurred mainly in the thoracic midgut and cardia, coincident with the accumulation of a promastigote secretory gel (PSG) plug in these anterior regions. The gel-like plug was isolated from flies with mature infections and found to contain predominantly leptomonad promastigotes. The PSG plug also contained the majority (75%) of the total metacyclic promastigote population in the sandflies, which were concentrated at the anterior pole. The PSG plug was found to be the main site of metacyclogenesis, and acted as a reservoir of leptomonad promastigotes from which metacyclic forms differentiated and migrated forward to promote the infective potential of the fly. The PSG plug occluded and distorted the midgut, forcing the stomodeal valve open and affecting the feeding success of the sandflies, such that they experienced difficulty in taking a full meal. Collectively, these data support the role of the PSG in the transmission of leishmaniasis, by conditioning the midgut environment for metacyclogenesis and altering the feeding ability of infected sandflies.
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Affiliation(s)
- M E Rogers
- Division of Molecular Biology and Immunology, Liverpool School of Tropical Medicine, UK.
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Vogt RG, Rogers ME, Franco MD, Sun M. A comparative study of odorant binding protein genes: differential expression of the PBP1-GOBP2 gene cluster inManduca sexta(Lepidoptera) and the organization of OBP genes inDrosophila melanogaster(Diptera). J Exp Biol 2002; 205:719-44. [PMID: 11914382 DOI: 10.1242/jeb.205.6.719] [Citation(s) in RCA: 110] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
SUMMARYInsects discriminate odors using sensory organs called olfactory sensilla, which display a wide range of phenotypes. Sensilla express ensembles of proteins, including odorant binding proteins (OBPs), olfactory receptors (ORs) and odor degrading enzymes (ODEs); odors are thought to be transported to ORs by OBPs and subsequently degraded by ODEs. These proteins belong to multigene families. The unique combinatorial expression of specific members of each of these gene families determines, in part, the phenotype of a sensillum and what odors it can detect. Furthermore, OBPs, ORs and ODEs are expressed in different cell types, suggesting the need for cell–cell communication to coordinate their expression. This report examines the OBP gene family. In Manduca sexta, the genes encoding PBP1Msex and GOBP2Msex are sequenced, shown to be adjacent to one another, and characterized together with OBP gene structures of other lepidoptera and Drosophila melanogaster. Expression of PBP1Msex, GOBP1Msex and GOBP2Msex is characterized in adult male and female antenna and in larval antenna and maxilla. The genomic organization of 25 D. melanogaster OBPs are characterized with respect to gene locus, gene cluster, amino acid sequence similarity, exon conservation and proximity to OR loci, and their sequences are compared with 14 M. sexta OBPs. Sensilla serve as portals of important behavioral information, and genes supporting sensilla function are presumably under significant evolutionary selective pressures. This study provides a basis for studying the evolution of the OBP gene family, the regulatory mechanisms governing the coordinated expression of OBPs, ORs and ODEs, and the processes that determine specific sensillum phenotypes.
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Affiliation(s)
- Richard G Vogt
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208 USA.
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Abstract
Poor balance is one of the most common risk factors for falling, a common cause of work-related injury and death. To evaluate the effects of a 10-week intervention program on balance in older adults, 12 participants aged 61-77 years (age = 70.4 +/- 5.4 years; mean +/- SD) completed an exercise program (60 min, 2 days.week-1 for 10 weeks) performed while laying/sitting on large air-filled exercise balls (Thera-Band). Several postural sway composite scores (determined while standing with feet apart and semitandem, eyes open and closed) improved (p < or = 0.05) including medial-lateral amplitude and speed of sway (reduced by approximately 9%), and instantaneous speed (reduced by approximately 13%). Reductions in XY area approached (p = 0.06) statistical significance and anterior-posterior amplitude and speed of sway did not change. Functional reach also improved (20.3%). These results suggest that challenging the physiological systems involved in balance control while on the nonstable support surface of the exercise balls improves both static and dynamic balance in older adults and may reduce the risk for falling.
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Affiliation(s)
- M E Rogers
- Center for Physical Activity and Aging, Department of Kinesiology and Sport Studies, 110 Heskett Center, Wichita State University, Wichita, Kansas 67260-0016, USA.
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Rogers ME, Krieger J, Vogt RG. Antennal SNMPs (sensory neuron membrane proteins) of Lepidoptera define a unique family of invertebrate CD36-like proteins. J Neurobiol 2001; 49:47-61. [PMID: 11536197 DOI: 10.1002/neu.1065] [Citation(s) in RCA: 123] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
SNMP1-Apol is an antennal-specific protein of the wild silk moth Antheraea polyphemus; the protein is abundantly expressed and localized to the receptor membranes of sex-pheromone specific olfactory sensory neurons (OSNs). SNMP1-Apol is thought to function in odor detection based on its olfactory-specific expression, localization within OSNs, developmental time of expression, and apparent homology to the CD36 family of membrane-bound receptor proteins. In the current study, SNMP1-Apol homologues were identified from the moths Bombyx mori, Heliothis virescens, and Manduca sexta. These species posses antennal mRNAs encoding proteins with amino acid sequence identities ranging from 75-80%; these proteins are collectively designated SNMP1. A second M. sexta SNMP homologue, previously identified and partially sequenced [Robertson et al.: Insect Mol Biol 8:501-518, 1999] was fully sequenced and characterized. The encoded protein shares only 26-27% sequence identity with the SNMP1 proteins, and is thus designated SNMP2-Msex. The SNMP sequences were used to identify 14 and four possible homologues in Drosophila melanogaster and Caenorhabditis elegans genome databases, respectively; thus, greatly expanding CD36 family membership among the invertebrate lineages. Despite their sequence difference, SNMP1-Msex and SNMP2-Msex expression is localized to OSNs and occurs simultaneously with the onset of olfactory function. These findings suggest that SNMPs play a central role in odor detection in insects, and that the CD36 gene family is widely represented among animal phyla. The SNMPs are the only identified neuronal members of the CD36 family, and as such expand the activities of this gene family into roles influencing brain function and behavioral action.
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Affiliation(s)
- M E Rogers
- Department of Biological Sciences, University of South Carolina, Columbia, South Carolina 29208, USA.
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Abstract
This study examined the attitudes toward exercise held by older adults within different stages of the exercise change model for the purpose of aiding health professionals in developing effective approaches that engage older adults in physical activity. Men and women (n = 116) between the ages of 60 and 93 years (73.9+/-6.6) completed a questionnaire used to categorize them into one of five stages of exercise change: precontemplation, contemplation, preparation, action, and maintenance. Participants also completed a questionnaire to assess four attitude factors related to exercise: tension release, health promotion, vigorous exercise, and social benefits. The Active older adults in this study reported positive attitudes toward exer cising for health benefits, social interaction, and tension release. Of these, the health benefits of exercise appear to be the most important factor in their participation in exercise. Therefore, prograns designed to engage older adults in regular physical activity should promote positive attitudes toward exercise, especially regarding the health related aspects of exercise.
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Affiliation(s)
- S C Rich
- Center for Physical Activity and Aging, Wichita State University, Kansas, USA.
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Affiliation(s)
- M E Rogers
- Department of Biological Sciences, Columbia University, New York, NY 10027, USA
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Rogers ME, Steinbrecht RA, Vogt RG. Expression of SNMP-1 in olfactory neurons and sensilla of male and female antennae of the silkmoth Antheraea polyphemus. Cell Tissue Res 2001; 303:433-46. [PMID: 11320659 DOI: 10.1007/s004410000305] [Citation(s) in RCA: 84] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
SNMP-1 (sensory neuron membrane protein 1) is an olfactory-specific membrane-bound protein which is homologous with the CD36 receptor family. Previous light level immunocytochemical studies suggested that SNMP-1 was localized in the dendrites and distal cell body of sex-pheromone-specific olfactory receptor neurons (ORN); these studies further suggested SNMP-1 was expressed in only one of two to three neurons in male-specific pheromone-sensitive trichoid sensilla. To better understand the expression and localization of SNMP-1, an immunocytochemical study was performed using electron microscopy to visualize the distribution of SNMP-1 among the neurons of several classes of olfactory sensilla of both male and female antennae of the silkmoth Antheraea polyphemus. SNMP-1 antigenicity was primarily restricted to the receptive dendritic membranes of ORNs of all sensilla types examined and was observed in cytosolic granules, but not plasma membranes, of the cell soma. Mean labeling densities ranged from 1 to 16 gold particles per micrometer of dendrite circumference; dendrites of trichoid and intermediate sensilla showed significantly higher labeling densities than those of basiconic sensilla. Larger dendrites of trichoid sensilla showed significantly higher mean labeling densities (13-16/micron) than smaller diameter dendrites (3-7/micron). Immunofluorescence studies using baculovirus expressed SNMP-1 and multiphoton photon laser scanning microscopy (MPLSM) indicated that rSNMP-1, which was post-translationally processed to the in vivo molecular weight, was inserted into the plasma membrane in a topography presenting extracellular epitopes. These studies suggest SNMP-1 is a common feature of the ORNs, is asymmetrically expressed among functionally distinct neurons, and possesses a topography which permits interaction with components of the extracellular sensillum lymph.
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Affiliation(s)
- M E Rogers
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA
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Otvos L, O I, Rogers ME, Consolvo PJ, Condie BA, Lovas S, Bulet P, Blaszczyk-Thurin M. Interaction between heat shock proteins and antimicrobial peptides. Biochemistry 2000; 39:14150-9. [PMID: 11087363 DOI: 10.1021/bi0012843] [Citation(s) in RCA: 259] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Drosocin, pyrrhocoricin, and apidaecin, representing the short (18-20 amino acid residues) proline-rich antibacterial peptide family, originally isolated from insects, were shown to act on a target bacterial protein in a stereospecific manner. Native pyrrhocoricin and one of its analogues designed for this purpose protect mice from bacterial challenge and, therefore, may represent alternatives to existing antimicrobial drugs. Furthermore, this mode of action can be a basis for the design of a completely novel set of antibacterial compounds, peptidic or peptidomimetic, if the interacting bacterial biopolymers are known. Recently, apidaecin was shown to enter Escherichia coli and subsequently kill bacteria through sequential interactions with diverse target macromolecules. In this paper report, we used biotin- and fluorescein-labeled pyrrhocoricin, drosocin, and apidaecin analogues to identify biopolymers that bind to these peptides and are potentially involved in the above-mentioned multistep killing process. Through use of a biotin-labeled pyrrhocoricin analogue, we isolated two interacting proteins from E. coli. According to mass spectrometry, Western blot, and fluorescence polarization, the short, proline-rich peptides bound to DnaK, the 70-kDa bacterial heat shock protein, both in solution and on the solid-phase. GroEL, the 60-kDa chaperonin, also bound in solution. Control experiments with an unrelated labeled peptide showed that while binding to DnaK was specific for the antibacterial peptides, binding to GroEL was not specific for these insect sequences. The killing of bacteria and DnaK binding are related events, as an inactive pyrrhocoricin analogue made of all-D-amino acids failed to bind. The pharmaceutical potential of the insect antibacterial peptides is underscored by the fact that pyrrhocoricin did not bind to Hsp70, the human equivalent of DnaK. Competition assay with unlabeled pyrrhocoricin indicated differences in GroEL and DnaK binding and a probable two-site interaction with DnaK. In addition, all three antibacterial peptides strongly interacted with two bacterial lipopolysaccharide (LPS) preparations in solution, indicating that the initial step of the bacterial killing cascade proceeds through LPS-mediated cell entry.
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Affiliation(s)
- L Otvos
- The Wistar Institute, 3601 Spruce Street, Philadelphia, Pennsylvania 19104, M-Scan, Inc., 606 Brandywine Parkway, West Chester, Pennsylvania 19380, USA.
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Egner PA, Stansbury KH, Snyder EP, Rogers ME, Hintz PA, Kensler TW. Identification and characterization of chlorin e(4) ethyl ester in sera of individuals participating in the chlorophyllin chemoprevention trial. Chem Res Toxicol 2000; 13:900-6. [PMID: 10995263 DOI: 10.1021/tx000069k] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Chlorophyllin (CHL), a mixture of water soluble derivatives of chlorophyll, has been shown to be an effective inhibitor of aflatoxin B(1) (AFB(1)) carcinogenesis and AFB(1)-DNA adduct formation in rainbow trout and rats [Breinholt, V., Hendricks, J., Pereira, C., Arbogast, D., and Bailey, G. (1995) Cancer Res. 55, 57-62; Kensler, T. W., Groopman, J. D., and Roebuck, B. D. (1998) Mutat. Res. 402, 165-172]. The chemopreventive action of CHL has been previously attributed to molecular complexing. In 1997, a randomized, double-blind clinical trial of CHL was conducted in Qidong, Jiangsu Province, People's Republic of China. At the completion of the study, when serum samples were regrouped by subject identification number, it was noted that many of the participant samples were green in color. Using HPLC, ESI/MS, and MS/MS techniques, serum samples from individuals receiving CHL were found to contain previously unreported copper chlorin e(4) ethyl ester (CuCle(4) ethyl ester) as well as copper chlorin e(4) (CuCle(4)). Both chlorins originated in the study tablet, were absorbed into the bloodstream, and conferred a green color to the sera. This initial finding of in vivo absorption and bioavailability of two chlorin derivatives suggests that the mechanism of CHL chemoprevention may lie in the actions of these two components in vivo in addition to preventing carcinogen absorption from the gut.
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Affiliation(s)
- P A Egner
- Department of Environmental Health Sciences, Johns Hopkins School of Hygiene and Public Health, Baltimore, Maryland 21205, USA.
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Abstract
Lowland gorillas eat the fruit and disperse the seeds of many tree species in the Lopé Reserve, Gabon. This study aimed to show whether deposition of seeds at gorilla ground nest sites conferred any advantage for germination and seedling establishment as compared to the fate of seeds deposited in gorilla dung on trails or under parents. Four tree species were chosen for study, which had a range of fruit types and fruiting patterns but which were all important foods for gorillas. Data showed that gorillas removed significant quantities of seeds from all four species and deposited them in dung at nest sites or on trail. Nest sites were not always favorable for germination, but the most favorable sites permitted the best survival and growth of any of the seedlings, including those deposited in dung on trail or scatter-dispersed under or away from parent canopies. Initial performance in the first few weeks after deposition was not always indicative of long-term survival and growth, so data collection over 1-2 years was absolutely essential. The main factors affecting seedling fate at nest sites appeared to be vegetation cover and desiccation. It is suggested that the nesting habits of gorillas are an additional factor encouraging the successful establishment of seedlings over and above the obvious advantages of large body size, gut capacity, and extended day ranges.
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Affiliation(s)
- M E Rogers
- ICAPB, University of Edinburgh, Scotland
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Otvos L, Pease AM, Bokonyi K, Giles-Davis W, Rogers ME, Hintz PA, Hoffmann R, Ertl HC. In situ stimulation of a T helper cell hybridoma with a cellulose-bound peptide antigen. J Immunol Methods 2000; 233:95-105. [PMID: 10648860 DOI: 10.1016/s0022-1759(99)00194-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Many enzyme-linked immunosorbent assays take advantage of immobilized antigens for the identification of antibody binding sites. Generally, the analysis of cellulose membrane-bound B-cell epitopes is currently considered of high utility. We adapted this methodology for the stimulation of a T helper cell hybridoma with known specificity. Forty overlapping peptides corresponding to the entire rabies virus nucleoprotein were synthesized in duplicates on a single sheet of 90x130 mm size amino-modified paper. The efficacy of the peptide assembly was monitored by color staining of the unreacted amino groups. After completion of the synthesis, the side-chain protecting groups were removed, and the membrane was thoroughly cleaned of all organic and inorganic contaminants. The membrane was cut into pieces, and a standard lymphokine release assay was performed directly from the paper-bound antigens. From all the 40 peptide spots only peptide 31D stimulated the proliferation of the 9C5.D8-H T-cell hybridoma, known to react to this peptide. By using this protocol, as little as 0.4 microgram (approximately 200 pmole) of peptide could be detected. According to mass spectrometry the T-cell stimulation proceeded as a true solid-phase assay. The peptide neither leached from the membrane nor was cleaved by the medium-splenocyte mixture. Additionally, tryptic digestion of the cellulose membrane released the expected peptide fragments.
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Affiliation(s)
- L Otvos
- The Wistar Institute, 3601 Spruce Street, Philadelphia, PA, USA.
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Vogt RG, Callahan FE, Rogers ME, Dickens JC. Odorant binding protein diversity and distribution among the insect orders, as indicated by LAP, an OBP-related protein of the true bug Lygus lineolaris (Hemiptera, Heteroptera). Chem Senses 1999; 24:481-95. [PMID: 10576256 DOI: 10.1093/chemse/24.5.481] [Citation(s) in RCA: 131] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Insect odorant binding proteins (OBPs) are thought to deliver odors to olfactory receptors, and thus may be the first biochemical step in odor reception capable of some level of odor discrimination. OBPs have been identified from numerous species of several insect orders, including Lepidoptera, Diptera, Coleoptera and Hymenoptera; all are holometabolous insects belonging to the monophyletic division of insects known as the Endopterygota. Recently, an antennal protein with OBP-like properties was identified from Lygus lineolaris, a hemipteran insect representing the Hemipteroid Assemblage, a sister division to the Endopterygota. The full length sequence of Lygus antennal protein (LAP) is presented in this report. In situ hybridization analysis revealed LAP expression in cell clusters associating with olfactory sensilla; expression was adult-specific, initiating in developing adult tissue during the transitional period that precedes the actual adult molt. Sequence analysis confirmed that LAP is homologous with the OBP-related protein family, and most similar to the OS-E and OS-F proteins of Drosophila, the ABPX proteins of Lepidoptera and the OBPRP proteins of the Coleoptera. Assuming that the OBP-related proteins represent one homologous family, the identification of LAP significantly expands the phylogenetic depth of that family and its underlying role in odor detection to encompass all members of the Endopterygota and Hemipteroid Assemblage, which comprise >90% of all insect species.
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Affiliation(s)
- R G Vogt
- Department of Biological Sciences, University of South Carolina, Columbia 29208, USA.
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