The Experts below are selected from a list of 30972 Experts worldwide ranked by ideXlab platform
John C. Beier - One of the best experts on this subject based on the ideXlab platform.
-
Mosquito ingestion of antibodies against mosquito Midgut microbiota improves conversion of ookinetes to oocysts for Plasmodium falciparum, but not P. yoelii
Parasitology International, 2011Co-Authors: Bruce H. Noden, Charles B. Pumpuni, Jefferson A. Vaughan, John C. BeierAbstract:The mosquito Midgut is a site of complex interactions between the mosquito, the malaria parasite and the resident bacterial flora. In laboratory experiments, we observed significant enhancement of Plasmodium falciparum oocyst production when Anopheles gambiae (Diptera: Culicidae) mosquitoes were membrane-fed on infected blood containing gametocytes from in vitro cultures mixed with sera from rabbits immunized with A. gambiae Midguts. To identify specific mechanisms, we evaluated whether the immune sera was interfering with the usual limiting activity of gram-negative bacteria in An. gambiae Midguts. Enhancement of P. falciparum infection rates occurred at some stage between the ookinete and oocyst stage and was associated with greater numbers of oocysts in mosquitoes fed on immune sera. The same immune sera did not affect the sporogonic development of P. yoelii, a rodent malaria parasite. Not only did antibodies in the immune sera recognize several types of Midgut-derived gram-negative bacteria (Pseudomonas spp. and Cedecea spp.), but gentamicin provided in the sugar meal 3 days before an infectious P. falciparum blood meal mixed with immune sera eliminated the enhancing effect. These results suggest that gram-negative bacteria, which normally impair P. falciparum development between the ookinete and oocyst stage, were altered by specific anti-bacterial antibodies produced by immunizing rabbits with non-antibiotic-treated Midgut lysates. Because of the differences in developmental kinetics between human and rodent malaria species, the anti-bacterial antibodies had no effect on P. yoelii because their ookinetes leave the Midgut much earlier than P. falciparum and so are not influenced as strongly by resident Midgut bacteria. While this study highlights the complex interactions occurring between the parasite, mosquito, and Midgut microbiota, the ultimate goal is to determine the influence of Midgut microbiota on Plasmodium development in anopheline Midguts in malaria endemic settings.
-
Midgut bacteria in anopheles gambiae and an funestus diptera culicidae from kenya and mali
Journal of Medical Entomology, 1998Co-Authors: Susanne C Straif, Charles M Mbogo, Abdoulaye Toure, Edward D Walker, Michael G Kaufman, Yeya T Toure, John C. BeierAbstract:: Field studies in Kenya and Mali investigated the prevalence of bacteria in the Midguts of malaria vectors, and the potential relationship between gram-negative bacteria species and Plasmodium falciparum sporozoites. Midguts were dissected from 2,430 mosquitoes: 863 Anopheles funestus Giles and 1,037 An. gambiae s.l. Giles from Kenya, and 530 An. gambiae s.l. from Mali. An. funestus had a higher prevalence of gram-negative bacteria (28.5%) compared with An. gambiae collected in Kenya and Mali (15.4 and 12.5%, respectively). Twenty different genera of bacteria were identified by gas chromatography from 73 bacterial isolates from mosquito Midguts. Pantoea agglomerans (Enterobacter agglomerans) was the most common species identified. There was no association between gram-negative bacteria in the Midgut and P. falciparum sporozoites in field-collected An. gambiae s.l. and An. funestus. However, An. funestus females that harbored gram positive bacteria were more likely to be infected with sporozoites compared with those with no cultivable bacteria or gram negative bacteria in their Midguts. Habitat-related variation in the prevalence of diverse types of bacteria in mosquitoes could influence malaria parasite development in mosquitoes and corresponding sporozoite prevalence.
-
bacterial population dynamics in three anopheline species the impact on plasmodium sporogonic development
American Journal of Tropical Medicine and Hygiene, 1996Co-Authors: Charles B. Pumpuni, John C. Beier, James Demaio, Melissa Kent, Jonathan R DavisAbstract:The functional role of bacteria in the Midgut of adult mosquitoes is unknown. In this study, we examined the population dynamics of Midgut bacteria of laboratory reared Anopheles stephensi, An. gambiae, and An. albimanus. Mosquito Midguts were dissected under sterile conditions and examined for the presence of bacteria using standard microbiologic techniques. Ninety percent and 73% (n = 30) of newly emerged An. gambiae and An. stephensi, respectively, harbored bacteria. In contrast, only 17% (n = 23) of An. albimanus harbored any bacteria. The bacterial population increased 11-40-fold in the presence of a blood meal, but then decreased to pre-blood meal levels in 3-5 days. Pseudomonas cepacia, Enterobacter agglomerans, and Flavobacterium spp. were found in all three anopheline species. Midgut bacteria were acquired both transtadially and through the sugar meal. Transtadial transmission was demonstrated by successfully passaging Escherichia coli HS5 from the larval to the adult stage. However, Midgut bacteria were acquired more efficiently through the sugar meal than through transtadial passage. An increase in Midgut bacterial counts after mosquitoes were exposed to a bacteria/sugar suspension significantly reduced oocyst infection rates and densities in Plasmodium falciparum-infected mosquito cohorts. Since bacteria occur naturally in wild mosquitoes, it may be possible to modify anopheline vector competence using introduced or indigenous bacteria.
-
exflagellation responses of cultured plasmodium falciparum haemosporida plasmodiidae gametocytes to human sera and Midguts of anopheline mosquitoes diptera culicidae
Journal of Medical Entomology, 1994Co-Authors: Chandana Mendis, Bruce H. Noden, John C. BeierAbstract:The process of exflagellation was quantified for cultured Plasmodium falciparum gametocytes exposed to human sera and Midgut homogenates from six vector species of Anopheles mosquitoes. Neither serum factors related to malaria exposure nor factors in the Midguts of taxonomically diverse anophelines had significant inhibitory effects on the exflagellation of P. falciparum microgametocytes. Therefore, differences in vector competence among anopheline species most likely are caused by vector-parasite interactions occurring after microgametogenesis.
Jesus G Valenzuela - One of the best experts on this subject based on the ideXlab platform.
-
binding of leishmania infantum lipophosphoglycan to the Midgut is not sufficient to define vector competence in lutzomyia longipalpis sand flies
mSphere, 2020Co-Authors: Iliano V Coutinhoabreu, Claudio Meneses, Shaden Kamhawi, James Oristian, Waldione De Castro, Timothy R Wilson, Rodrigo P Soares, Valeria M Borges, Albert Descoteaux, Jesus G ValenzuelaAbstract:ABSTRACT The major surface lipophosphoglycan (LPG) of Leishmania parasites is critical to vector competence in restrictive sand fly vectors in mediating Leishmania attachment to the Midgut epithelium, considered essential to parasite survival and development. However, the relevance of LPG for sand flies that harbor multiple species of Leishmania remains elusive. We tested binding of Leishmania infantum wild-type (WT), LPG-defective (Δlpg1 mutants), and add-back (Δlpg1 + LPG1) lines to sand fly Midguts in vitro and their survival in Lutzomyia longipalpis sand flies in vivo. Le. infantum WT parasites attached to the Lu. longipalpis Midgut in vitro, with late-stage parasites binding to Midguts in significantly higher numbers than were seen with early-stage promastigotes. Δlpg1 mutants did not bind to Lu. longipalpis Midguts, and this was rescued in the Δlpg1 + LPG1 lines, indicating that Midgut binding is mediated by LPG. When Lu. longipalpis sand flies were infected with the Le. infantum WT or Le. infantum Δlpg1 or Le. infantum Δlpg1 + LPG1 line of the BH46 or BA262 strains, the BH46 Δlpg1 mutant, but not the BA262 Δlpg1 mutant, survived and grew to numbers similar to those seen with the WT and Δlpg1 + LPG1 lines. Exposure of BH46 and BA262 Δlpg1 mutants to blood-engorged Midgut extracts led to mortality of the BA262 Δlpg1 but not the BH46 Δlpg1 parasites. These findings suggest that Le. infantum LPG protects parasites on a strain-specific basis early in infection, likely against toxic components of blood digestion, but that it is not necessary to prevent Le. infantum evacuation along with the feces in the permissive vector Lu. longipalpis. IMPORTANCE It is well established that the presence of LPG is sufficient to define the vector competence of restrictive sand fly vectors with respect to Leishmania parasites. However, the permissiveness of other sand flies with respect to multiple Leishmania species suggests that other factors might define vector competence for these vectors. In this study, we investigated the underpinnings of Leishmania infantum survival and development in its natural vector, Lutzomyia longipalpis. We found that LPG-mediated Midgut binding persists in late-stage parasites. This observation is of relevance for the understanding of vector-parasite molecular interactions and suggests that only a subset of infective metacyclic-stage parasites (metacyclics) lose their ability to attach to the Midgut, with implications for parasite transmission dynamics. However, our data also demonstrate that LPG is not a determining factor in Leishmania infantum retention in the Midgut of Lutzomyia longipalpis, a permissive vector. Rather, LPG appears to be more important in protecting some parasite strains from the toxic environment generated during blood meal digestion in the insect gut. Thus, the relevance of LPG in parasite development in permissive vectors appears to be a complex issue and should be investigated on a strain-specific basis.
-
leishmania infection induces a limited differential gene expression in the sand fly Midgut
BMC Genomics, 2020Co-Authors: Iliano V Coutinhoabreu, Claudio Meneses, Shaden Kamhawi, Tiago D Serafim, Fabiano Oliveira, Jesus G ValenzuelaAbstract:Sand flies are the vectors of Leishmania parasites. To develop in the sand fly Midgut, Leishmania multiplies and undergoes various stage differentiations giving rise to the infective form, the metacyclic promastigotes. To determine the changes in sand fly Midgut gene expression caused by the presence of Leishmania, we performed RNA-Seq of uninfected and Leishmania infantum-infected Lutzomyia longipalpis Midguts from seven different libraries corresponding to time points which cover the various Leishmania developmental stages. The combined transcriptomes resulted in the de novo assembly of 13,841 sand fly Midgut transcripts. Importantly, only 113 sand fly transcripts, about 1%, were differentially expressed in the presence of Leishmania parasites. Further, we observed distinct differentially expressed sand fly Midgut transcripts corresponding to the presence of each of the various Leishmania stages suggesting that each parasite stage influences Midgut gene expression in a specific manner. Two main patterns of sand fly gene expression modulation were noted. At early time points (days 1–4), more transcripts were down-regulated by Leishmania infection at large fold changes (> 32 fold). Among the down-regulated genes, the transcription factor Forkhead/HNF-3 and hormone degradation enzymes were differentially regulated on day 2 and appear to be the upstream regulators of nutrient transport, digestive enzymes, and peritrophic matrix proteins. Conversely, at later time points (days 6 onwards), most of the differentially expressed transcripts were up-regulated by Leishmania infection with small fold changes (< 32 fold). The molecular functions of these genes have been associated with the metabolism of lipids and detoxification of xenobiotics. Overall, our data suggest that the presence of Leishmania produces a limited change in the Midgut transcript expression profile in sand flies. Further, Leishmania modulates sand fly gene expression early on in the developmental cycle in order to overcome the barriers imposed by the Midgut, yet it behaves like a commensal at later time points where a massive number of parasites in the anterior Midgut results only in modest changes in Midgut gene expression.
-
binding of leishmania infantum lpg to the Midgut is not sufficient to define vector competence in lutzomyia longipalpis sand flies
bioRxiv, 2020Co-Authors: Iliano V Coutinhoabreu, Claudio Meneses, Shaden Kamhawi, James Oristian, Waldione De Castro, Timothy R Wilson, Rodrigo P Soares, Valeria M Borges, Albert Descoteaux, Jesus G ValenzuelaAbstract:The major surface lipophosphoglycan (LPG) of Leishmania parasites is critical to vector competence in restrictive sand fly vectors by mediating Leishmania attachment to the Midgut epithelium, considered essential to parasite survival and development. However, the relevance of LPG for sand flies that harbor multiple species of Leishmania remains elusive. We tested binding of Leishmania infantum wild type (WT) LPG-defective (Δlpg1) mutants and add-back lines (Δlpg1 + LPG1)& to sand fly Midguts in vitro and their survival in Lutzomyia longipalpis sand flies in vivo. Le. infantum WT parasites attached to the Lu. longipalpis Midguts in vitro with late-stage parasites binding in significantly higher numbers compared to early-stage stage promastigotes. Δlpg1 mutants did not bind Lu. longipalpis Midguts, and this was rescued in the Δlpg1 + LPG1 lines, indicating that Midgut binding is mediated by LPG. When Lu. longipalpis sand flies were infected with either Le. infantum WT, Δlpg1, or Δlpg1 + LPG1 of the BH46 or BA262 strains, the BH46 Δlpg1 mutant, but not the BA262 Δlpg1 mutant, survived and grew to similar numbers as the WT and Δlpg1 + LPG1 lines. Exposure of BH46 and BA262 Δlpg1 mutants to blood engorged Midgut extracts led to the mortality of the BA262 Δlpg1 but not the BH46 Δlpg1 parasites. These findings suggest that Le. infantum LPG protects parasites on a strain-specific basis early in infection, likely against toxic components of blood digestion, however, it is not necessary to prevent Le. infantum evacuation along with the feces in the permissive vector Lu. longipalpis.
-
leishmania infection induces a limited differential gene expression in the sand fly Midgut
bioRxiv, 2019Co-Authors: Iliano V Coutinhoabreu, Claudio Meneses, Shaden Kamhawi, Tiago D Serafim, Fabiano Oliveira, Jesus G ValenzuelaAbstract:BackgroundPhlebotomine sand flies are the vectors of Leishmania worldwide. To develop in the sand fly Midgut, Leishmania multiplies and undergoes multiple stage differentiations leading to the infective form, the metacyclic promastigotes. To gain a better understanding of the influence of Leishmania infection in Midgut gene expression, we performed RNA-Seq comparing uninfected Lutzomyia longipalpis Midguts and Leishmania infantum-infected Lutzomyia longipalpis Midguts at seven time points which cover the various developmental Leishmania stages including early time points when blood digestion is taking place and late time points when the parasites are undergoing metacyclogenesis. ResultsOut of over 13,841 transcripts assembled de novo, only 113 sand fly transcripts, about 1%, were differentially expressed. Further, we observed a low overlap of differentially expressed sand fly transcripts across different time points suggesting a specific influence of each Leishmania stage on Midgut gene expression. Two main patterns of sand fly gene expression modulation were noticed. At early time points (days 1-4), more transcripts were down-regulated by Leishmania infection at large fold changes (> -32 fold). Among the down-regulated genes, the transcription factor Forkhead/HNF-3 and hormone degradation enzymes were differentially regulated on day 4 and appear to be the upstream regulators of nutrient transport, digestive enzymes, and peritrophic matrix proteins. Conversely, at later time points (days 6 onwards), most of the differentially expressed transcripts were up-regulated by small fold changes (< 32 fold), and the molecular function of such genes are associated with the metabolism of lipids and detoxification of xenobiotics (P450). ConclusionOverall, it appears that Leishmania modulates sand fly gene expression early on in order to overcome the barriers imposed by the Midgut, yet it behaves like a commensal at later time points, when modest Midgut gene expression changes correlate with a massive amount of parasites in the anterior Midgut.
-
exploring the mialome of ticks an annotated catalogue of Midgut transcripts from the hard tick dermacentor variabilis acari ixodidae
BMC Genomics, 2008Co-Authors: Jennifer M Anderson, Daniel E. Sonenshine, Jesus G ValenzuelaAbstract:Ticks are obligate blood feeders. The Midgut is the first major region of the body where blood and microbes ingested with the blood meal come in contact with the tick's internal tissues. Little is known about protein expression in the digestive tract of ticks. In this study, for analysis of global gene expression during tick attachment and feeding, we generated and sequenced 1,679 random transcripts (ESTs) from cDNA libraries from the Midguts of female ticks at varying stages of feeding. Sequence analysis of the 1,679 ESTs resulted in the identification of 835 distinct transcripts, from these, a total of 82 transcripts were identified as proteins putatively directly involved in blood meal digestion, including enzymes involved in oxidative stress reduction/antimicrobial activity/detoxification, peptidase inhibitors, protein digestion (cysteine-, aspartic-, serine-, and metallo-peptidases), cell, protein and lipid binding including mucins and iron/heme metabolism and transport. A lectin-like protein with a high match to lectins in other tick species, allergen-like proteins and surface antigens important in pathogen recognition and/or antimicrobial activity were also found. Furthermore, Midguts collected from the 6-day-fed ticks expressed twice as many transcripts involved in bloodmeal processing as Midguts from unfed/2-day-fed ticks. This tissue-specific transcriptome analysis provides an opportunity to examine the global expression of transcripts in the tick Midgut and to compare the gut response to host attachment versus blood feeding and digestion. In contrast to those in salivary glands of other Ixodid ticks, most proteins in the D. variabilis Midgut cDNA library were intracellular. Of the total ESTs associated with a function, an unusually large number of transcripts were associated with peptidases, cell, lipid and protein binding, and oxidative stress or detoxification. Presumably, this is consistent with their role in intracellular processing of the blood meal and response to microbial infections. The presence of many proteins with similar functions is consistent with the hypothesis that gene duplication contributed to the successful adaptation of ticks to hematophagy. Furthermore, these transcripts may be useful to scientists investigating the role of the tick Midgut in blood-meal digestion, antimicrobial activity or the transmission of tick-borne pathogens.
Walter R Terra - One of the best experts on this subject based on the ideXlab platform.
-
prey digestion in the Midgut of the predatory bug podisus nigrispinus hemiptera pentatomidae
Journal of Insect Physiology, 2012Co-Authors: Maria Do Carmo Queiroz Fialho, Walter R Terra, Alberto F Ribeiro, Nathalia R Moreira, Jose Cola Zanuncio, Jose Eduardo SerraoAbstract:Abstract Pre-oral digestion is described as the liquefaction of the solid tissues of the prey by secretions of the predator. It is uncertain if pre-oral digestion means pre-oral dispersion of food or true digestion in the sense of the stepwise bond breaking of food polymers to release monomers to be absorbed. Collagenase is the only salivary proteinase, which activity is significant (10%) in relation to Podisus nigrispinus Midgut activities. This suggests that pre-oral digestion in P. nigrispinus consists in prey tissue dispersion. This was confirmed by the finding of prey muscles fibers inside P. nigrispinus Midguts. Soluble Midgut hydrolases from P. nigrispinus were partially purified by ion-exchange chromatography, followed by gel filtration. Two cathepsin L-like proteinases (CAL1 and CAL2) were isolated with the properties: CAL1 (14.7 kDa, pH optimum (pHo) 5.5, km with carbobenzoxy-Phe-Arg-methylcoumarin, Z-FR-MCA, 32 μM); CAL2 (17 kDa, pHo 5.5, km 11 μM Z-FR-MCA). Only a single molecular species was found for the other enzymes with the following properties are: amylase (43 kDa, pHo 5.5, km 0.1% starch), aminopeptidase (125 kDa, pHo 5.5, km 0.11 mM l -Leucine-p-nitroanilide), α-glucosidase (90 kDa, pHo 5.0, km 5 mM with p-nitrophenyl α- d -glucoside). CAL molecular masses are probably underestimated due to interaction with the column. Taking into account the distribution of hydrolases along P. nigrispinus Midguts, carbohydrate digestion takes place mainly at the anterior Midgut, whereas protein digestion occurs mostly in middle and posterior Midgut, as previously described in seed- sucker and blood-feeder hemipterans.
-
the cathepsin l like proteinases from the Midgut of tenebrio molitor larvae sequence properties immunocytochemical localization and function
Insect Biochemistry and Molecular Biology, 2005Co-Authors: Plinio T Cristofoletti, Alberto F Ribeiro, Walter R TerraAbstract:Abstract CDNAs coding for five procathepsin L-like proteinases (pCALs) were cloned and sequenced from a cDNA library prepared from Tenebrio molitor larval Midguts: pCAL1a (with the isoforms pCAL1b and pCAL1c), pCAL2, and pCAL3. All the pCALs have the active residues Cys 25, His 169, Asn 175, and Gln 19 (papain numbering), the ERFNIN motif of papain-like enzymes and their sequences are homologous to cathepsin L enzymes. pCAL1a was expressed in bacterial systems. It is auto-catalytically activated at low pH, has kinetic properties and N-terminal sequence identical to hemocyte cathepsin L-like proteinase (CAL) and was used to raise antibodies. Semi-quantitative RT-PCR data showed that mRNAs for pCAL2 and pCAL3 were transcribed in Midgut and in lesser amounts in hemolymph, whereas that for pCAL1a was transcribed in these tissues and also in fat body, Malpighian tubules, and carcass. Imunochemical detection recognized pCAL1a translation in all tissue homogenates, except anterior Midgut. At this region, the presence of pCAL2 is suggested on the grounds of electrophoretical migration and high recovery of CAL2 activity from anterior Midgut cells and from isolated Midgut contents. Immunocytochemical localization data revealed that pCAL1a occurs in lysosome-like vesicles in all tissues, except anterior Midgut, where a labelling considered to correspond to pCAL2 is found in large acidic granules being released by apocrine secretion. Putative pCAL2 was also detected in Midgut contents, probably in the form of CAL2, the major luminal CAL, which was purified to homogeneity. A cladogram of insect CALs result in a monophyletic branch with lysosomal T. molitor enzymes and enzymes from five insect orders and in a polyphyletic array of coleopteran sequences, including digestive CALs from T. molitor . The data suggest that only Coleoptera have digestive CALs that may originate by gene duplication and independent evolution relative to the gene encoding the lysosomal enzyme.
-
secretion of β glycosidase by middle Midgut cells and its recycling in the Midgut of tenebrio molitor larvae
Journal of Insect Physiology, 2002Co-Authors: Alexandre Ferreira, Walter R Terra, Alberto F Ribeiro, C R FerreiraAbstract:There are four β-glycosidases (βgly1, βgly2, βgly3, and βgly4) in Tenebrio molitor Midgut larvae. βgly1 and βgly2 have identical kinetic properties, and differ in a few amino acid residues. Purified βgly1 was used to raise antibodies in a rabbit. The resulting antiserum recognizes in a Western blot only βgly1 and βgly2 in Midgut tissue homogenates and contents. An immunocytochemical study carried out using confocal fluorescence and immunogold techniques showed that βgly1+βgly2 are secreted by exocytosis mainly from the distal part of the second third of T. molitor Midguts. This is the first immunocytochemical study of an insect digestive enzyme that does not have polymers as substrates. Enzyme assays with 0.3 mM amygdalin, a condition that detects only βgly1+βgly2, revealed that most of those β-glycosidases are found in the lumen of anterior and middle Midgut. This supports the hypothesis that a countercurrent flux of fluid occurs in T. molitor Midgut that is able to carry βgly1 and βgly2 to anterior Midgut, in agreement with the enzyme recycling mechanism thought to occur in most insects.
-
α galactosidases from the larval Midgut of tenebrio molitor coleoptera and spodoptera frugiperda lepidoptera
Comparative Biochemistry and Physiology B, 2001Co-Authors: Gisele A Grossmann, Walter R TerraAbstract:Abstract There are three Midgut α-galactosidases (TG1, TG2, TG3) from Tenebrio molitor larvae that are partially resolved by ion-exchange chromatography. The enzymes have approximately the same pH optimum (5.0), pl value (4.6) and Mr value (46 000–49 000) as determined by gel filtration or native electrophoresis run in polyacrylamide gels with different concentrations. Substrate specificities and functions were proposed for the major T. molitor Midgut α-galactosidases (TG2 and TG3) based on chromatographic, carbodiimide inactivation, Tris inhibition, and on substrate competition data. Thus, TG2 would hydrolyse α-1,6-galactosaccharides, exemplified by raffinose, whereas TG3 would act on melibiose and apparently also on digalactosyldiglyceride, the most important compound in the thylacoid membranes of chloroplasts. Most galactoside digestion should occur in the lumen of the first two thirds of T. molitor larval Midguts, since α-galactosidase activity predominates there. Spodoptera frugiperda larvae have three Midgut α-galactosidases (SG1, SG2, SG3) partially resolved by ion-exchange chromatography. The enzymes have similar pH optimum (5.8), pl value (7.2) and Mr value (46 000–52 000), and at least the major α-galactosidase must have an active carboxyl group in the active site. Based on data similar to those described for T. molitor, SG1 and SG3 should hydrolyse melibiose and SG3 should digest raffinose and, perhaps, also digalactosyldiglyceride. The Midgut distribution of α-galactosidase activity supports the proposal that α-galactosidase digestion occurs at the surface of anterior Midgut cells in Spodoptera frugiperda larvae.
-
The effect of dietary plant glycosides on larval Midgut β-glucosidases from Spodoptera frugiperda and Diatraea saccharalis
Insect Biochemistry and Molecular Biology, 1997Co-Authors: Clélia Ferreira, Josér.p. Parra, Walter R TerraAbstract:Spodoptera frugiperda development and Midgut β-glucosidase activity are not affected by salicin and amygdalin present in their diets up to a concentration of at least 0.5%, suggesting that glycoside tolerance results from aglycone detoxification. Both salicin and amygdalin affect Diatraea saccharalis development, whereas only 0.5% amygdalin causes a decrease in Midgut β-glucosidase activity. There are three electrophoretically-resolved β-glucosidases in D. saccharalis Midguts. β-Glucosidases 1 and 3 are thought to hydrolyze amygdalin to glucose and prunasin, and β-glucosidase 2 to hydrolyze prunasin to glucose and the cyanogenic mandelonitrile. A short (48-h) exposure to 0.5 % amygdalin causes a decrease of β-glucosidase 1 and 3, whereas a long exposure (whole larval stage) depresses β-glucosidase 2 activity. This suggests that glycoside tolerance may result from reduction in the Midgut aryl β-glucosidase activity without affecting the glycosyl β-glucosidase activity, which hydrolyzes cellobiose and other β-glycans.
Terry W. Pearson - One of the best experts on this subject based on the ideXlab platform.
-
identification of Midgut proteins that are differentially expressed in trypanosome susceptible and normal tsetse flies glossina morsitans morsitans
Insect Biochemistry and Molecular Biology, 2005Co-Authors: J.d. Haddow, R. H. Gooding, Lee R. Haines, Robert W Olafson, Terry W. PearsonAbstract:Molecules in the Midgut of tsetse flies (Diptera: Glossinidiae) are thought to play important roles in the life cycle of African trypanosomes by influencing initial parasite establishment and subsequent differentiation events that ultimately lead to maturation of mammal-infective trypanosomes. The molecular composition of the tsetse Midgut is, therefore, of critical importance to disease transmission by these medically important vectors. In this study we compared protein expression profiles of Midguts of the salmon mutant and wild type Glossina morsitans morsitans Westwood that display marked differences in their susceptibility to infection by African trypanosomes. Isotope coded affinity tag (ICAT) technology was used to identify 207 proteins including 17 that were up regulated and nine that were down regulated in the salmon mutants. Several of the up regulated molecules were previously described as tsetse Midgut or salivary gland proteins. Of particular interest was the up regulation in the salmon flies of tsetse Midgut EP protein, a recently described molecule with lectin-like activity that was also found to be induced in tsetse by bacterial challenge. The up regulation of the EP protein in Midguts of salmon mutants was confirmed by two-dimensional gel electrophoresis and tandem mass spectrometry.
-
The major protein in the Midgut of teneral Glossina morsitans morsitans is a molecular chaperone from the endosymbiotic bacterium Wigglesworthia glossinidia.
Insect biochemistry and molecular biology, 2002Co-Authors: Lee R. Haines, R. H. Gooding, J.d. Haddow, Terry W. PearsonAbstract:Molecules in the Midgut of the tsetse fly (Diptera: Glossinidiae) are thought to play an important role in the life cycle of African trypanosomes by influencing their initial establishment in the Midgut and subsequent differentiation events that ultimately affect parasite transmission. It is thus important to determine the molecular composition of the tsetse Midgut to aid in understanding disease transmission by these medically important insect vectors. Here, we report that the most abundant protein in the Midguts of teneral (unfed) Glossina morsitans morsitans is a 60 kDa molecular chaperone of bacterial origin. Two species of symbiotic bacteria reside in the tsetse Midgut, Sodalis glossinidius and Wigglesworthia glossinidia. To determine the exact origin of the 60 kDa molecule, a protein microchemical approach involving two-dimensional (2-D) gel electrophoresis and mass spectrometry was used. Peptide mass maps were compared to virtual peptide maps predicted for S. glossinidius and W. glossinidia 60 kDa chaperone sequences. Four signature peptides were identified, revealing that the source of the chaperone was W. glossinidia. Comparative 2-D gel electrophoresis and immunoblotting further revealed that this protein was localized to the bacteriome and not the distal portion of the tsetse Midgut. The possible function of this highly abundant endosymbiont chaperone in the tsetse Midgut is discussed.
Shaden Kamhawi - One of the best experts on this subject based on the ideXlab platform.
-
binding of leishmania infantum lipophosphoglycan to the Midgut is not sufficient to define vector competence in lutzomyia longipalpis sand flies
mSphere, 2020Co-Authors: Iliano V Coutinhoabreu, Claudio Meneses, Shaden Kamhawi, James Oristian, Waldione De Castro, Timothy R Wilson, Rodrigo P Soares, Valeria M Borges, Albert Descoteaux, Jesus G ValenzuelaAbstract:ABSTRACT The major surface lipophosphoglycan (LPG) of Leishmania parasites is critical to vector competence in restrictive sand fly vectors in mediating Leishmania attachment to the Midgut epithelium, considered essential to parasite survival and development. However, the relevance of LPG for sand flies that harbor multiple species of Leishmania remains elusive. We tested binding of Leishmania infantum wild-type (WT), LPG-defective (Δlpg1 mutants), and add-back (Δlpg1 + LPG1) lines to sand fly Midguts in vitro and their survival in Lutzomyia longipalpis sand flies in vivo. Le. infantum WT parasites attached to the Lu. longipalpis Midgut in vitro, with late-stage parasites binding to Midguts in significantly higher numbers than were seen with early-stage promastigotes. Δlpg1 mutants did not bind to Lu. longipalpis Midguts, and this was rescued in the Δlpg1 + LPG1 lines, indicating that Midgut binding is mediated by LPG. When Lu. longipalpis sand flies were infected with the Le. infantum WT or Le. infantum Δlpg1 or Le. infantum Δlpg1 + LPG1 line of the BH46 or BA262 strains, the BH46 Δlpg1 mutant, but not the BA262 Δlpg1 mutant, survived and grew to numbers similar to those seen with the WT and Δlpg1 + LPG1 lines. Exposure of BH46 and BA262 Δlpg1 mutants to blood-engorged Midgut extracts led to mortality of the BA262 Δlpg1 but not the BH46 Δlpg1 parasites. These findings suggest that Le. infantum LPG protects parasites on a strain-specific basis early in infection, likely against toxic components of blood digestion, but that it is not necessary to prevent Le. infantum evacuation along with the feces in the permissive vector Lu. longipalpis. IMPORTANCE It is well established that the presence of LPG is sufficient to define the vector competence of restrictive sand fly vectors with respect to Leishmania parasites. However, the permissiveness of other sand flies with respect to multiple Leishmania species suggests that other factors might define vector competence for these vectors. In this study, we investigated the underpinnings of Leishmania infantum survival and development in its natural vector, Lutzomyia longipalpis. We found that LPG-mediated Midgut binding persists in late-stage parasites. This observation is of relevance for the understanding of vector-parasite molecular interactions and suggests that only a subset of infective metacyclic-stage parasites (metacyclics) lose their ability to attach to the Midgut, with implications for parasite transmission dynamics. However, our data also demonstrate that LPG is not a determining factor in Leishmania infantum retention in the Midgut of Lutzomyia longipalpis, a permissive vector. Rather, LPG appears to be more important in protecting some parasite strains from the toxic environment generated during blood meal digestion in the insect gut. Thus, the relevance of LPG in parasite development in permissive vectors appears to be a complex issue and should be investigated on a strain-specific basis.
-
leishmania infection induces a limited differential gene expression in the sand fly Midgut
BMC Genomics, 2020Co-Authors: Iliano V Coutinhoabreu, Claudio Meneses, Shaden Kamhawi, Tiago D Serafim, Fabiano Oliveira, Jesus G ValenzuelaAbstract:Sand flies are the vectors of Leishmania parasites. To develop in the sand fly Midgut, Leishmania multiplies and undergoes various stage differentiations giving rise to the infective form, the metacyclic promastigotes. To determine the changes in sand fly Midgut gene expression caused by the presence of Leishmania, we performed RNA-Seq of uninfected and Leishmania infantum-infected Lutzomyia longipalpis Midguts from seven different libraries corresponding to time points which cover the various Leishmania developmental stages. The combined transcriptomes resulted in the de novo assembly of 13,841 sand fly Midgut transcripts. Importantly, only 113 sand fly transcripts, about 1%, were differentially expressed in the presence of Leishmania parasites. Further, we observed distinct differentially expressed sand fly Midgut transcripts corresponding to the presence of each of the various Leishmania stages suggesting that each parasite stage influences Midgut gene expression in a specific manner. Two main patterns of sand fly gene expression modulation were noted. At early time points (days 1–4), more transcripts were down-regulated by Leishmania infection at large fold changes (> 32 fold). Among the down-regulated genes, the transcription factor Forkhead/HNF-3 and hormone degradation enzymes were differentially regulated on day 2 and appear to be the upstream regulators of nutrient transport, digestive enzymes, and peritrophic matrix proteins. Conversely, at later time points (days 6 onwards), most of the differentially expressed transcripts were up-regulated by Leishmania infection with small fold changes (< 32 fold). The molecular functions of these genes have been associated with the metabolism of lipids and detoxification of xenobiotics. Overall, our data suggest that the presence of Leishmania produces a limited change in the Midgut transcript expression profile in sand flies. Further, Leishmania modulates sand fly gene expression early on in the developmental cycle in order to overcome the barriers imposed by the Midgut, yet it behaves like a commensal at later time points where a massive number of parasites in the anterior Midgut results only in modest changes in Midgut gene expression.
-
binding of leishmania infantum lpg to the Midgut is not sufficient to define vector competence in lutzomyia longipalpis sand flies
bioRxiv, 2020Co-Authors: Iliano V Coutinhoabreu, Claudio Meneses, Shaden Kamhawi, James Oristian, Waldione De Castro, Timothy R Wilson, Rodrigo P Soares, Valeria M Borges, Albert Descoteaux, Jesus G ValenzuelaAbstract:The major surface lipophosphoglycan (LPG) of Leishmania parasites is critical to vector competence in restrictive sand fly vectors by mediating Leishmania attachment to the Midgut epithelium, considered essential to parasite survival and development. However, the relevance of LPG for sand flies that harbor multiple species of Leishmania remains elusive. We tested binding of Leishmania infantum wild type (WT) LPG-defective (Δlpg1) mutants and add-back lines (Δlpg1 + LPG1)& to sand fly Midguts in vitro and their survival in Lutzomyia longipalpis sand flies in vivo. Le. infantum WT parasites attached to the Lu. longipalpis Midguts in vitro with late-stage parasites binding in significantly higher numbers compared to early-stage stage promastigotes. Δlpg1 mutants did not bind Lu. longipalpis Midguts, and this was rescued in the Δlpg1 + LPG1 lines, indicating that Midgut binding is mediated by LPG. When Lu. longipalpis sand flies were infected with either Le. infantum WT, Δlpg1, or Δlpg1 + LPG1 of the BH46 or BA262 strains, the BH46 Δlpg1 mutant, but not the BA262 Δlpg1 mutant, survived and grew to similar numbers as the WT and Δlpg1 + LPG1 lines. Exposure of BH46 and BA262 Δlpg1 mutants to blood engorged Midgut extracts led to the mortality of the BA262 Δlpg1 but not the BH46 Δlpg1 parasites. These findings suggest that Le. infantum LPG protects parasites on a strain-specific basis early in infection, likely against toxic components of blood digestion, however, it is not necessary to prevent Le. infantum evacuation along with the feces in the permissive vector Lu. longipalpis.
-
leishmania infection induces a limited differential gene expression in the sand fly Midgut
bioRxiv, 2019Co-Authors: Iliano V Coutinhoabreu, Claudio Meneses, Shaden Kamhawi, Tiago D Serafim, Fabiano Oliveira, Jesus G ValenzuelaAbstract:BackgroundPhlebotomine sand flies are the vectors of Leishmania worldwide. To develop in the sand fly Midgut, Leishmania multiplies and undergoes multiple stage differentiations leading to the infective form, the metacyclic promastigotes. To gain a better understanding of the influence of Leishmania infection in Midgut gene expression, we performed RNA-Seq comparing uninfected Lutzomyia longipalpis Midguts and Leishmania infantum-infected Lutzomyia longipalpis Midguts at seven time points which cover the various developmental Leishmania stages including early time points when blood digestion is taking place and late time points when the parasites are undergoing metacyclogenesis. ResultsOut of over 13,841 transcripts assembled de novo, only 113 sand fly transcripts, about 1%, were differentially expressed. Further, we observed a low overlap of differentially expressed sand fly transcripts across different time points suggesting a specific influence of each Leishmania stage on Midgut gene expression. Two main patterns of sand fly gene expression modulation were noticed. At early time points (days 1-4), more transcripts were down-regulated by Leishmania infection at large fold changes (> -32 fold). Among the down-regulated genes, the transcription factor Forkhead/HNF-3 and hormone degradation enzymes were differentially regulated on day 4 and appear to be the upstream regulators of nutrient transport, digestive enzymes, and peritrophic matrix proteins. Conversely, at later time points (days 6 onwards), most of the differentially expressed transcripts were up-regulated by small fold changes (< 32 fold), and the molecular function of such genes are associated with the metabolism of lipids and detoxification of xenobiotics (P450). ConclusionOverall, it appears that Leishmania modulates sand fly gene expression early on in order to overcome the barriers imposed by the Midgut, yet it behaves like a commensal at later time points, when modest Midgut gene expression changes correlate with a massive amount of parasites in the anterior Midgut.
-
the vectorial competence of phlebotomus sergenti is specific for leishmania tropica and is controlled by species specific lipophosphoglycan mediated Midgut attachment
Parasitology, 2000Co-Authors: Shaden Kamhawi, G B Modi, Paulo F P Pimenta, Edgar Rowton, David L SacksAbstract:The vectorial competence of Phlebotomus sergenti for 3 Old World species of Leishmania, L. tropica, L. major and L. donovani, was investigated in vivo and by in vitro Midgut binding assays using living promastigotes and purified lipophosphoglycan (LPG). P. sergenti consistently showed a high specificity for L. tropica strains, which were able to develop mature, potentially transmissible infections. The loss of infection with L. major and L. donovani correlated with the excretion of the digested bloodmeal. These strains were able to produce sustained infections in the Midguts of their appropriate vectors, P. papatasi and P. argentipes, respectively. In in vitro binding assays, a significantly higher number of L. tropica procyclic promastigotes attached to the Midgut lining of P. sergenti, compared to those of L. major and L. donovani (P < 0.05). The prediction that the species specificity of Midgut attachment is controlled by polymorphic structures on the parasite LPG was supported by the finding that P. sergenti Midguts were intensely stained following incubation with purified phosphoglycan (PG) from L. tropica compared with PGs from L. major or L. donovani. The results provide further evidence that LPG structural polymorphisms are driven by the species diversity of molecules present on the sandfly Midgut that function as parasite attachment sites.
