Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0851341 (infestation)
 10,121 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The disorders of the gonadotropic axis have been studied during the course of a "chronic" african trypanosomiasis induced experimentally in rats inoculated by the variant Trypanosoma brucei brucei AnTat 1.1.E. The levels of serum and pituitary LH as well as serum testosterone and corticosterone have been determined, during the infestation, at a particular period of the circadian cycle, in regard to the parasitemia variations. In addition, the inoculation of trypanosomal component fractions [obtained by concanavalin-A sepharose chromatography (conA-components)], has been performed in an attempt to define more exactly the nature of factor(s) producing the hypotestosteronemia in rats. This work evidenced that the hormonal parameter levels were predominantly decreased at the trypanolytic phase during the evolution of the disease. The action towards the hypothalamo-pituitary gonadal axis was attributed not only to peculiar trypanosomal enzyme(s) [a serine, thiol-dependent, cation sensitive endoprotease with a post-proline cleaving activity (purified from unretained conA fraction)], but also to protein and/or glycoprotein factor(s) released by the trypanosomes (components with affinity to the lectin).
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PMID:Experimental "chronic" African trypanosomiasis: endocrine dysfunctions generated by parasitic components released during the tryptanolytic phase in rats. 822 86

The biological effects of affinity purified seed lectin from African yam bean, Sphenostylis stenocarpa (Harms), were tested on Clavigralla tomentosicollis (Stal) in an artificial seed system. S. stenocarpa was extracted from two African yam bean accessions: Enugu 95-3 and Enugu 98-2. Lectins from both accessions were highly toxic to the insect at 1.0% dry weight. For nymphs feeding on Enugu 95-3 and Enugu 98-2, survival ranged from 16.0 to 24.0% and 4.0 to 16.0% at 1.0 and 2.0% dry weight dietary lectin levels, respectively. From 4.0 to 8.0% dry weight of both lectins, no nymph survived up to 6 d after infestation. At 1.0% dry weights of Enugu 95-3 and Enugu 98-2 lectins, there was a significant delay in total developmental time (5.35 and 5.18 d), reduced survival (24.0% and 16.0%), and reduced growth (0.15+/-0.02 and 0.14+/-0.01) and resistance (61.85+/-9.78 and 57.79+/-3.80) indices, respectively. S. stenocarpa from Enugu 98-2 was the most toxic, with an LD50 of 0.43%, compared with an LD50 of 0.65% for S. stenocarpa from Enugu 95-3. The results of this investigation indicate that there exists in C. tomentosicollis physiological systems vulnerable to African yam bean lectins.
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PMID:Biological effects of African yam bean lectins on Clavigralla tomentosicollis (Hemiptera: Coreidae). 1142 30

Adult Psoroptes ovis were successively extracted in saline, 1% Tween, 1% Triton and 8 m urea +0.1% CHAPS. The Triton extract was separated into fractions which did or did not bind to ConA lectin. Using QuilA as adjuvant, both Triton fractions and the saline, Tween and urea extracts were tested separately as candidate protective antigens against a P. ovis challenge infestation in sheep. All induced circulating antibody responses, but the saline and Tween extracts also stimulated significant protective effects in those sheep which developed active disease. Compared to control sheep injected with adjuvant only, these immunized animals had more than two and seven-fold reductions in mean lesion areas and mite numbers, respectively.
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PMID:Attempts to immunize sheep against the scab mite, Psoroptes ovis. 1210 15

Infestation with parasitic helminths is a common problem in human populations of third world countries and is ubiquitous in livestock and other domestic animals. The cell-membrane efflux pump, P-glycoprotein (Pgp), appears to contribute to anthelmintic resistance. Pgp have been identified from both phyla of parasitic helminths, Platyhelmintha and Nematoda, and alterations in expression levels and allele frequencies of Pgp in anthelmintic-resistant populations have been observed in nematodes. Localisation of Pgp has been studied in the free-living nematode Caenorhabditis elegans and in the sheep parasite Haemonchus contortus using specific monoclonal antibodies or lectins. Reversing agents used in human studies, such as the calcium-channel blocker verapamil (VPL), appear to have similar effects in helminths as they do in human cancer cells: the efficacy of drug treatment is increased in drug-resistant parasites when reversing agents are co-administered with the anthelmintic. The functional role of the Pgp glycosylation was also studied using a lectin specific for the alpha-mannosyl residues and showed that resistance can be associated with a decreased affinity of the lectin for Pgp sites and that up to 50% reversion in the resistance to benzimidazoles (BZ) can be obtained using this lectin. Furthermore, the current knowledge on the role of Pgp in molecular mechanisms of drug resistance in the parasitic protozoan genus Trypanosoma is discussed. In some Trypanosoma species it was shown that drug resistance was associated with reduced uptake and in other ones with increased efflux. Several trypanosome Pgp-coding sequences have been described. In contrast to earlier data, most recent observations, based on experimentally overexpressed Pgp in Trypanosoma brucei, indicate a possible involvement in the mechanism of drug resistance in this parasite.
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PMID:P-glycoprotein in helminths: function and perspectives for anthelmintic treatment and reversal of resistance. 1367 40

We previously cloned and characterized a novel jacalin-like lectin gene from wheat (Triticum aestivum) plants that responds to infestation by Hessian fly (Mayetiola destructor) larvae, a major dipteran pest of this crop. The infested resistant plants accumulated higher levels of Hfr-1 (for Hessian fly-responsive gene 1) transcripts compared with uninfested or susceptible plants. Here, we characterize the soluble and active recombinant His(6)-HFR1 protein isolated from Escherichia coli. Functional characterization of the protein using hemagglutination assays revealed lectin activity. Glycan microarray-binding assays indicated strong affinity of His(6)-HFR1 to Manalpha1-6(Manalpha1-3)Man trisaccharide structures. Resistant wheat plants accumulated high levels of HFR1 at the larval feeding sites, as revealed by immunodetection, but the avirulent larvae were deterred from feeding and consumed only small amounts of the lectin. Behavioral studies revealed that avirulent Hessian fly larvae on resistant plants exhibited prolonged searching and writhing behaviors as they unsuccessfully attempted to establish feeding sites. During His(6)-HFR1 feeding bioassays, Drosophila melanogaster larvae experienced significant delays in growth and pupation, while percentage mortality increased with progressively higher concentrations of His(6)-HFR1 in the diet. Thus, HFR1 is an antinutrient to dipteran larvae and may play a significant role in deterring Hessian fly larvae from feeding on resistant wheat plants.
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PMID:Functional characterization of HFR1, a high-mannose N-glycan-specific wheat lectin induced by Hessian fly larvae. 1846 54

Citrus plants are currently facing biotic and abiotic stresses. Therefore, the characterization of molecular traits involved in the response mechanisms to stress could facilitate selection of resistant varieties. Although large cDNA microarray profiling has been generated in citrus tissues, the available protein expression data are scarce. In this study, to identify differentially expressed proteins in Citrus clementina leaves after infestation by the two-spotted spider mite Tetranychus urticae, a proteome comparison was undertaken using two-dimensional gel electrophoresis. The citrus leaf proteome profile was also compared with that of leaves treated over 0-72h with methyl jasmonate, a compound playing a key role in the defense mechanisms of plants to insect/arthropod attack. Significant variations were observed for 110 protein spots after spider mite infestation and 67 protein spots after MeJA treatments. Of these, 50 proteins were successfully identified by liquid chromatography-mass spectrometry-tandem mass spectrometry. The majority constituted photosynthesis- and metabolism-related proteins. Five were oxidative stress associated enzymes, including phospholipid glutathione peroxidase, a salt stressed associated protein, ascorbate peroxidase and Mn-superoxide dismutase. Seven were defense-related proteins, such as the pathogenesis-related acidic chitinase, the protease inhibitor miraculin-like protein, and a lectin-like protein. This is the first report of differentially regulated proteins after T. urticae attack and exogenous MeJA application in citrus leaves.
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PMID:Comparative analysis of proteome changes induced by the two spotted spider mite Tetranychus urticae and methyl jasmonate in citrus leaves. 2092 59

Because many species of gastropods are intermediate hosts for trematodes, these molluscs are often used as model-organisms in the studies of invertebrate immune system. Revealing of the ways in which the defense factors functioning became possible due to the use of the methods of molecular biology. Contemporary molecular methods allow analyzing the defense factors allocations and levels of their expression. We investigated the expression of genes encoding defense factors in gastropods by the example of the snail Planorbarius corneus from water bodies of the Leningrad Oblast under infestation with trematods. The snails naturally infested with the parthenites of trematode species belonging to the families Strigeidae, Notocotylidae, Plagiorchiidae, and Schistosomatida were used as the experimental sample. Uninfested snails were used as a control sample. Several genes encoding the factors, which have been recently found involved in the anti-trematode defense reactions in pulmonates, were chosen, namely fibrinogen-related protein, C-lectin, calcium-binding protein, and cystatin-like protein. The genes' expression was analyzed on total mRNA samples by the reverse transcription with the polymerase chain reaction. It was shown than expression levels of the genes under consideration are different in uninfested snails and in the snails infested with different trematode species. Thus, in the mollusks infested with the parthenites of Cotylurus sp. and Bilharziella polonica, the expression levels of the genes of all factors under study were increased, while in the infested Notocotylus sp. n Plagiorchis sp., only expression levels of C-lectin and cystatin-like protein were increased. Results of the expression analysis confirm the role of hemocytes and cells of hepatopancreas in the production of humoral defense factors. In the snails infested with trematodes, the expression levels of C-lectin and calcium-binding protein genes are increased in haemocytes, while the genes of fibrinogen-related and cystatin-like proteins are activated in the hepatopancreas. Our data also confirm the role of the factors examined in the anti-trematode defense reactions in pulmonates.
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PMID:[Expression of genes encoding defense factors in the snail Planorbarius corneus (Gastropoda, Pulmonata) infested with trematodes]. 2106 90

Broad spectrum protection against different insects and pathogens requires multigene engineering. However, such broad spectrum protection against biotic stress is provided by a single protein in some medicinal plants. Therefore, tobacco chloroplasts were transformed with the agglutinin gene from Pinellia ternata (pta), a widely cultivated Chinese medicinal herb. Pinellia ternata agglutinin (PTA) was expressed up to 9.2% of total soluble protein in mature leaves. Purified PTA showed similar hemagglutination activity as snowdrop lectin. Artificial diet with purified PTA from transplastomic plants showed marked and broad insecticidal activity. In planta bioassays conducted with T0 or T1 generation PTA lines showed that the growth of aphid Myzus persicae (Sulzer) was reduced by 89%-92% when compared with untransformed (UT) plants. Similarly, the larval survival and total population of whitefly (Bemisia tabaci) on transplastomic lines were reduced by 91%-93% when compared with UT plants. This is indeed the first report of lectin controlling whitefly infestation. When transplastomic PTA leaves were fed to corn earworm (Helicoverpa zea), tobacco budworm (Heliothis virescens) or the beet armyworm (spodoptera exigua), 100% mortality was observed against all these three insects. In planta bioassays revealed Erwinia population to be 10,000-fold higher in control than in PTA lines. Similar results were observed with tobacco mosaic virus (TMV) challenge. Therefore, broad spectrum resistance to homopteran (sap-sucking), Lepidopteran insects as well as anti-bacterial or anti-viral activity observed in PTA lines provides a new option to engineer protection against biotic stress by hyper-expression of an unique protein that is naturally present in a medicinal plant.
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PMID:Pinellia ternata agglutinin expression in chloroplasts confers broad spectrum resistance against aphid, whitefly, Lepidopteran insects, bacterial and viral pathogens. 2207 60

The interaction between Hessian fly (Mayetiola destructor) and wheat (Triticum aestivum) involves a gene-for-gene resistance mechanism. The incompatible interaction leading to resistance involves up-regulation of several Hfr (Hessian fly responsive) genes encoding proteins with potential insecticidal activity. The encoded proteins HFR-1, HFR-2 and HFR-3 all possess lectin-like domains. HFR-1 and HFR-3 were produced as recombinant proteins using Escherichia coli and Pichia pastoris, respectively as expression hosts. Purified recombinant proteins were assayed for insecticidal effects towards cereal aphid (Sitobion avenae), an insect to which wheat shows only tolerance. Both HFR-1 and HFR-3 were found to be insecticidal towards S. avenae when fed in artificial diet. Although HFR-3 has sequence similarity and similar chitin-binding activity to wheat germ agglutinin (WGA), the latter protein was almost non-toxic to S. avenae. HFR-3 binds strongly to aphid midguts after ingestion, whereas WGA binds but does not persist over a feed-chase period. Quantitative PCR showed that Hfr-3 mRNA does not increase in level after cereal aphid infestation. The results suggest that the lack of effective resistance to cereal aphid in wheat is not due to an absence of genes encoding suitable insecticidal proteins, but results from a failure to up-regulate gene expression in response to aphid attack.
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PMID:Insecticidal activity of wheat Hessian fly responsive proteins HFR-1 and HFR-3 towards a non-target wheat pest, cereal aphid (Sitobion avenae F.). 2260 18

Scabies is a parasitic infestation of the skin by the mite Sarcoptes scabiei that causes significant morbidity worldwide, in particular within socially disadvantaged populations. In order to identify mechanisms that enable the scabies mite to evade human immune defenses, we have studied molecules associated with proteolytic systems in the mite, including two novel scabies mite serine protease inhibitors (SMSs) of the serpin superfamily. Immunohistochemical studies revealed that within mite-infected human skin SMSB4 (54 kDa) and SMSB3 (47 kDa) were both localized in the mite gut and feces. Recombinant purified SMSB3 and SMSB4 did not inhibit mite serine and cysteine proteases, but did inhibit mammalian serine proteases, such as chymotrypsin, albeit inefficiently. Detailed functional analysis revealed that both serpins interfered with all three pathways of the human complement system at different stages of their activation. SMSB4 inhibited mostly the initial and progressing steps of the cascades, while SMSB3 showed the strongest effects at the C9 level in the terminal pathway. Additive effects of both serpins were shown at the C9 level in the lectin pathway. Both SMSs were able to interfere with complement factors without protease function. A range of binding assays showed direct binding between SMSB4 and seven complement proteins (C1, properdin, MBL, C4, C3, C6 and C8), while significant binding of SMSB3 occurred exclusively to complement factors without protease function (C4, C3, C8). Direct binding was observed between SMSB4 and the complement proteases C1s and C1r. However no complex formation was observed between either mite serpin and the complement serine proteases C1r, C1s, MASP-1, MASP-2 and MASP-3. No catalytic inhibition by either serpin was observed for any of these enzymes. In summary, the SMSs were acting at several levels mediating overall inhibition of the complement system and thus we propose that they may protect scabies mites from complement-mediated gut damage.
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PMID:Novel scabies mite serpins inhibit the three pathways of the human complement system. 2279 50


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