RESUMO
The ban on the use of antibiotics as feed additives for animal growth promotion in the European Union and United States and the expectation of this trend to further expand to other countries in the short term have prompted a surge in probiotic research. Multi-species probiotics including safe and compatible strains with the ability to bind different nutritional lectins with detrimental effects on poultry nutrition could replace antibiotics as feed additives. Lactobacillus salivarius LET201, Lactobacillus reuteri LET210, Enterococcus faecium LET301, Propionibacterium acidipropionici LET103 and Bifidobacterium infantis CRL1395 have proved to be compatible as evaluated through three different approaches: the production and excretion of antimicrobial compounds, growth inhibition by competition for essential nutrients and physical contact, and a combination of both. The safety of P. acidipropionici LET103 was confirmed, since no expression of virulence factors or antibiotic resistance was detected. The innocuity of E. faecium LET301 should be further evaluated, since the presence of genes coding for certain virulence factors (gelE, efaAfm and efaAfs) was observed, albeit no expression of gelE was previously detected for this strain and there are no reports of involvement of efaAfm in animal pathogenicity. Finally, a combination of the five strains effectively protected intestinal epithelial cells of broilers from the cytotoxicity of mixtures of soybean agglutinin, wheat germ agglutinin and concanavalin A. To our knowledge, this is the first time that a combination of strains is evaluated for their protection against lectins that might be simultaneously present in poultry feeds.
Assuntos
Anti-Infecciosos/metabolismo , Bifidobacterium longum subspecies infantis/metabolismo , Enterococcus faecium/metabolismo , Lactobacillus/metabolismo , Doenças das Aves Domésticas/prevenção & controle , Probióticos/farmacologia , Propionibacterium/metabolismo , Animais , Antibiose , Bifidobacterium longum subspecies infantis/genética , Bifidobacterium longum subspecies infantis/crescimento & desenvolvimento , Bifidobacterium longum subspecies infantis/patogenicidade , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Concanavalina A/toxicidade , Farmacorresistência Bacteriana , Enterococcus faecium/genética , Enterococcus faecium/crescimento & desenvolvimento , Enterococcus faecium/patogenicidade , Células Epiteliais/efeitos dos fármacos , Células Epiteliais/fisiologia , Lactobacillus/genética , Lactobacillus/crescimento & desenvolvimento , Lactobacillus/patogenicidade , Lectinas/metabolismo , Modelos Teóricos , Lectinas de Plantas/toxicidade , Probióticos/efeitos adversos , Propionibacterium/genética , Propionibacterium/crescimento & desenvolvimento , Propionibacterium/patogenicidade , Ligação Proteica , Proteínas de Soja/toxicidade , Virulência , Fatores de Virulência/genética , Aglutininas do Germe de Trigo/toxicidadeRESUMO
Vatairea guianensis lectin (VGL), Dalbergiae tribe, is a N-acetyl-galactosamine (GalNAc)/Galactose (Gal) lectin previously purified and characterized. In this work, we report its structural features, obtained from bioinformatics tools, and its inflammatory effect, obtained from a rat paw edema model. The VGL model was obtained by homology with the lectin of Vatairea macrocarpa (VML) as template, and we used it to demonstrate the common characteristics of legume lectins, such as the jellyroll motif and presence of a metal-binding site in the vicinity of the carbohydrate-recognition domain (CRD). Protein-ligand docking revealed favorable interactions with N-acetyl-d-galactosamine, d-galactose and related sugars as well as several biologically relevant N- and O-glycans. In vivo testing of paw edema revealed that VGL induces edematogenic effect involving prostaglandins, interleukins and VGL CRD. Taken together, these data corroborate with previous reports showing that VGL interacts with N- and/or O-glycans of molecular targets, particularly in those presenting galactosides in their structure, contributing to the lectin inflammatory effect.
Assuntos
Edema/induzido quimicamente , Edema/metabolismo , Fabaceae/química , Simulação de Acoplamento Molecular , Lectinas de Plantas , Animais , Edema/patologia , Lectinas de Plantas/química , Lectinas de Plantas/isolamento & purificação , Lectinas de Plantas/toxicidade , Ratos , Ratos WistarRESUMO
Plant lectins, which are proteins/glycoproteins present in a wide range of vegetables, fruits, cereals and beans, are resistant to digestive enzymes and food cooking temperatures. They bind reversibly to specific glycosidic residues expressed on the membrane of intestinal epithelial cells (IEC) and cause anti-nutritional effects in humans and animals. Soybean lectin (SBA) has been detected in poultry diets, and its ability to bind to the intestinal epithelium has been reported. The development of new methods for removing SBA from feeds or to prevent interaction with the intestinal mucosa is of interest. In this study, the in vitro cytotoxicity of SBA on IEC of chicks was demonstrated for the first time. The LD50, assessed after 2 h exposure of IEC to SBA, was 6.13 µg mL(-1) The ability of Bifidobacterium infantis CRL1395 to bind SBA on the bacterial envelope was confirmed, and prevention of IEC cytotoxicity by lectin removal was demonstrated. Safety of B. infantis CRL1395, resistance to gastrointestinal stress and adhesion were also determined. It was concluded that the early administration of B. infantis CRL1395 to chicks would effectively reduce the toxicity of SBA. Besides, it would favour the colonization of the gut with a beneficial microbiota.
Assuntos
Bifidobacterium longum subspecies infantis/metabolismo , Citotoxinas/farmacologia , Células Epiteliais/efeitos dos fármacos , Mucosa Intestinal/efeitos dos fármacos , Lectinas de Plantas/toxicidade , Proteínas de Soja/toxicidade , Animais , Galinhas , Mucosa Intestinal/citologia , Mucosa Intestinal/microbiologia , Intestinos/microbiologia , Dose Letal Mediana , Lectinas de Plantas/metabolismo , Probióticos , Proteínas de Soja/metabolismoRESUMO
A glycosylated lectin (CTL) with specificity for mannose and glucose has been detected and purified from seeds of Centrolobium tomentosum, a legume plant from Dalbergieae tribe. It was isolated by mannose-sepharose affinity chromatography. The primary structure was determined by tandem mass spectrometry and consists of 245 amino acids, similar to other Dalbergieae lectins. CTL structures were solved from two crystal forms, a monoclinic and a tetragonal, diffracted at 2.25 and 1.9 Å, respectively. The carbohydrate recognition domain (CRD), metal-binding site and glycosylation site were characterized, and the structural basis for mannose/glucose-binding was elucidated. The lectin adopts the canonical dimeric organization of legume lectins. CTL showed acute inflammatory effect in paw edema model. The protein was subjected to ligand screening (dimannosides and trimannoside) by molecular docking, and interactions were compared with similar lectins possessing the same ligand specificity. This is the first crystal structure of mannose/glucose native seed lectin with proinflammatory activity isolated from the Centrolobium genus.
Assuntos
Edema/induzido quimicamente , Fabaceae/química , Lectina de Ligação a Manose , Simulação de Acoplamento Molecular , Lectinas de Plantas , Sementes/química , Sequência de Aminoácidos , Animais , Modelos Animais de Doenças , Edema/patologia , Feminino , Glicosilação , Inflamação/induzido quimicamente , Inflamação/patologia , Lectina de Ligação a Manose/química , Lectina de Ligação a Manose/toxicidade , Espectrometria de Massas , Lectinas de Plantas/química , Lectinas de Plantas/toxicidade , Pegadas de Proteínas , Ratos , Ratos Wistar , Relação Estrutura-AtividadeRESUMO
Uma cadela sem raça definida, de cinco anos de idade, deu entrada para atendimento apresentando sintomatologia neurológica aguda caracterizada por ataxia, rigidez muscular de membros torácicos, marcante depressão, letargia, fraqueza, incoordenação, midríase e diminuição bilateral de reflexo pupilar. A paciente foi internada, sendo observada uma evolução do quadro para tetraparesia com sialorreia e prostração após 12 horas. Houve dois episódios de vômito 24 horas após o internamento, evidenciando-se grande quantidade de sementes de Talisia esculenta inteiras e trituradas. A literatura cita casos de intoxicação por ingestão de folhas e frutos da T. esculenta em bovinos e ovinos com sintomatologia semelhante. O objetivo do presente relato é registrar o referido caso, uma vez que não foram encontradas referências abordando tal tema em animais de companhia na literatura consultada.(AU)
A five-year-old mongrel bitch was admitted for acute care presenting neurological symptoms such as ataxia, muscular stiffness on forelimbs, pronounced depression, lethargy, weakness, incoordination, mydriasis and bilaterally decreased pupillary reflex. Twelve hours post-admittance, the patient developed tetraparesis, salivation and prostration; 24 hours post-admittance, the patient vomited both crushed and intact seeds of Talisia esculenta. Literature reports cases of sheep and cattle poisoning with similar symptoms by ingestion of fruits and leaves of T. esculenta. The aim of this article is to report this case, since no such records in companion animals are available.(AU)
Una perra mestiza de cinco años fue atendida presentando sintomatología neurológica aguda caracterizada por ataxia, rigidez muscular en miembros anteriores, marcada depresión, letargia, debilidad, incoordinación, midriasis y disminución bilateral del reflejo pupilar. La paciente fue internada y se pudo observar una evolución del cuadro a una tetraparesia com sialorrea y postración después de 12 horas. Veinticuatro horas después de internada, la paciente vomitó, momento en el cual se hizo evidente la presencia de una gran cantidad de semillas enteras y trituradas de Talisia esculenta. La literatura cita casos de intoxicación por ingesta de hojas y frutos de T. esculenta en bovinos y ovinos, que presentan una sintomatología similar. El objetivo del presente relato es registrar el caso referido, ya que no se encontraron trabajos en la literatura consultada, relacionados con este tema en animales de compañía.(AU)
Assuntos
Animais , Feminino , Cães , Doenças Transmitidas por Alimentos/diagnóstico , Doenças Transmitidas por Alimentos/veterinária , Sementes/toxicidade , Plantas Tóxicas , Frutas/toxicidade , Lectinas de Plantas/toxicidadeRESUMO
Uma cadela sem raça definida, de cinco anos de idade, deu entrada para atendimento apresentando sintomatologia neurológica aguda caracterizada por ataxia, rigidez muscular de membros torácicos, marcante depressão, letargia, fraqueza, incoordenação, midríase e diminuição bilateral de reflexo pupilar. A paciente foi internada, sendo observada uma evolução do quadro para tetraparesia com sialorreia e prostração após 12 horas. Houve dois episódios de vômito 24 horas após o internamento, evidenciando-se grande quantidade de sementes de Talisia esculenta inteiras e trituradas. A literatura cita casos de intoxicação por ingestão de folhas e frutos da T. esculenta em bovinos e ovinos com sintomatologia semelhante. O objetivo do presente relato é registrar o referido caso, uma vez que não foram encontradas referências abordando tal tema em animais de companhia na literatura consultada.
A five-year-old mongrel bitch was admitted for acute care presenting neurological symptoms such as ataxia, muscular stiffness on forelimbs, pronounced depression, lethargy, weakness, incoordination, mydriasis and bilaterally decreased pupillary reflex. Twelve hours post-admittance, the patient developed tetraparesis, salivation and prostration; 24 hours post-admittance, the patient vomited both crushed and intact seeds of Talisia esculenta. Literature reports cases of sheep and cattle poisoning with similar symptoms by ingestion of fruits and leaves of T. esculenta. The aim of this article is to report this case, since no such records in companion animals are available.
Una perra mestiza de cinco años fue atendida presentando sintomatología neurológica aguda caracterizada por ataxia, rigidez muscular en miembros anteriores, marcada depresión, letargia, debilidad, incoordinación, midriasis y disminución bilateral del reflejo pupilar. La paciente fue internada y se pudo observar una evolución del cuadro a una tetraparesia com sialorrea y postración después de 12 horas. Veinticuatro horas después de internada, la paciente vomitó, momento en el cual se hizo evidente la presencia de una gran cantidad de semillas enteras y trituradas de Talisia esculenta. La literatura cita casos de intoxicación por ingesta de hojas y frutos de T. esculenta en bovinos y ovinos, que presentan una sintomatología similar. El objetivo del presente relato es registrar el caso referido, ya que no se encontraron trabajos en la literatura consultada, relacionados con este tema en animales de compañía.
Assuntos
Feminino , Animais , Cães , Doenças Transmitidas por Alimentos/diagnóstico , Doenças Transmitidas por Alimentos/veterinária , Plantas Tóxicas , Sementes/toxicidade , Frutas/toxicidade , Lectinas de Plantas/toxicidadeRESUMO
Entomotoxic plant lectins have been extensively studied in the past two decades, yet the exact mechanisms underlying their toxic effects remain unknown. This study investigated the effects of Dioclea violacea lectin (DVL) on larval development in Anagasta kuehniella. Chronic exposure of larvae (from neonates to the fourth instar) demonstrated that DVL interfered with larval growth, retarding development and decreasing larval mass without affecting survival. DVL decreased trypsin-like, chymotrypsin-like, and α-amylase activities and proved resistant to proteolysis by midgut proteases up to 24h. Shorter exposures to dietary DVL had no effect on midgut enzyme activity. Feeding fourth-instar larvae with fluorescently-labeled DVL revealed lectin binding to the peritrophic membrane.
Assuntos
Dioclea , Mariposas/enzimologia , Lectinas de Plantas/metabolismo , Animais , Peso Corporal , Trato Gastrointestinal/enzimologia , Larva/efeitos dos fármacos , Larva/enzimologia , Larva/crescimento & desenvolvimento , Mariposas/efeitos dos fármacos , Mariposas/crescimento & desenvolvimento , Lectinas de Plantas/toxicidade , ProteóliseRESUMO
For many years, several studies have been employing lectin from vegetables in order to prove its toxic effect on various cell lines. In this work, we analyzed the cytotoxic, antiproliferative, and post-incubatory effect of pure tepary bean lectins on four lines of malignant cells: C33-A; MCF-7; SKNSH, and SW480. The tests were carried out employing MTT and 3[H]-thymidine assays. The results showed that after 24 h of lectin exposure, the cells lines showed a dose-dependent cytotoxic effect, the effect being higher on MCF-7, while C33-A showed the highest resistance. Cell proliferation studies showed that the toxic effect induced by lectins is higher even when lectins are removed, and in fact, the inhibition of proliferation continues after 48 h. Due to the use of two techniques to analyze the cytotoxic and antiproliferative effect, differences were observed in the results, which can be explained by the fact that one technique is based on metabolic reactions, while the other is based on the 3[H]-thymidine incorporated in DNA by cells under division. These results allow concluding that lectins exert a cytotoxic effect after 24 h of exposure, exhibiting a dose-dependent effect. In some cases, the cytotoxic effect is higher even when the lectins are eliminated, however, in other cases, the cells showed a proliferative effect.
Assuntos
Antineoplásicos Fitogênicos/farmacologia , Phaseolus/química , Lectinas de Plantas/farmacologia , Antineoplásicos Fitogênicos/isolamento & purificação , Antineoplásicos Fitogênicos/toxicidade , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Relação Dose-Resposta a Droga , Humanos , Lectinas de Plantas/isolamento & purificação , Lectinas de Plantas/toxicidade , Fatores de TempoRESUMO
Evidence is accumulating that commonly used pesticides are linked to decline of pollinator populations; adverse effects of three neonicotinoids on bees have led to bans on their use across the European Union. Developing insecticides that pose negligible risks to beneficial organisms such as honeybees is desirable and timely. One strategy is to use recombinant fusion proteins containing neuroactive peptides/proteins linked to a 'carrier' protein that confers oral toxicity. Hv1a/GNA (Galanthus nivalis agglutinin), containing an insect-specific spider venom calcium channel blocker (ω-hexatoxin-Hv1a) linked to snowdrop lectin (GNA) as a 'carrier', is an effective oral biopesticide towards various insect pests. Effects of Hv1a/GNA towards a non-target species, Apis mellifera, were assessed through a thorough early-tier risk assessment. Following feeding, honeybees internalized Hv1a/GNA, which reached the brain within 1 h after exposure. However, survival was only slightly affected by ingestion (LD50>100 µg bee(-1)) or injection of fusion protein. Bees fed acute (100 µg bee(-1)) or chronic (0.35 mg ml(-1)) doses of Hv1a/GNA and trained in an olfactory learning task had similar rates of learning and memory to no-pesticide controls. Larvae were unaffected, being able to degrade Hv1a/GNA. These tests suggest that Hv1a/GNA is unlikely to cause detrimental effects on honeybees, indicating that atracotoxins targeting calcium channels are potential alternatives to conventional pesticides.
Assuntos
Abelhas/efeitos dos fármacos , Bloqueadores dos Canais de Cálcio/toxicidade , Inseticidas/toxicidade , Lectinas de Ligação a Manose/toxicidade , Lectinas de Plantas/toxicidade , Venenos de Aranha/toxicidade , Animais , Abelhas/crescimento & desenvolvimento , Bloqueadores dos Canais de Cálcio/metabolismo , Galanthus/química , Inseticidas/metabolismo , Larva/efeitos dos fármacos , Aprendizagem/efeitos dos fármacos , Lectinas de Ligação a Manose/genética , Lectinas de Ligação a Manose/metabolismo , Lectinas de Plantas/genética , Lectinas de Plantas/metabolismo , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/metabolismo , Proteínas Recombinantes de Fusão/toxicidade , Venenos de Aranha/genética , Venenos de Aranha/metabolismoRESUMO
The objective of this work was to study the insecticidal effect of labramin, a protein that shows lectin-like properties. Labramin was isolated from seeds of the Beach Apricot tree, Labramia bojeri A. DC ex Dubard (Ericales: Sapotaceae), and assessed against the development of the Mediterranean flour moth Ephestia kuehniella Zeller (Lepidoptera: Pyralidae), an important pest of stored products such as corn, wheat, rice, and flour. Results showed that labramin caused 90% larval mortality when incorporated in an artificial diet at a level of 1% (w/w). The presence of 0.25% labramin in the diet affected the larval and pupal developmental periods and the percentage of emerging adults. Treatments resulted in elevated levels of trypsin activity in midgut and fecal materials, indicating that labramin may have affected enzyme-regulatory mechanisms by perturbing peritrophic membranes in the midgut of is. kuehniella larvae. The results of dietary experiments with E. kuehniella larvae showed a reduced efficiency for the conversion of ingested and digested food, and an increase in approximate digestibility and metabolic cost. These findings suggest that labramin may hold promise as a control agent to engineer crop plants for insect resistance.
Assuntos
Inseticidas/isolamento & purificação , Mariposas/efeitos dos fármacos , Extratos Vegetais/química , Lectinas de Plantas/isolamento & purificação , Sapotaceae/química , Animais , Ingestão de Alimentos/efeitos dos fármacos , Eletroforese em Gel de Poliacrilamida , Feminino , Inseticidas/toxicidade , Larva/efeitos dos fármacos , Mariposas/enzimologia , Mariposas/crescimento & desenvolvimento , Extratos Vegetais/toxicidade , Lectinas de Plantas/toxicidade , Proteínas de Plantas/isolamento & purificação , Proteínas de Plantas/toxicidade , Sementes/química , Tripsina/metabolismoRESUMO
Natural intoxication of livestock by ingestion of Ipomoea asarifolia leaves has been reported to occur widely in Brazil. Previous studies carried out by our research group provided strong evidence that a lectin could be involved with the toxic properties of I. asarifolia. To reinforce this hypothesis, a lectin-enriched fraction (LEF) was isolated from I. asarifolia leaves and its toxic effects were assessed. Leaves of I. asarifolia were excised from plants growing widely in the field, mechanically wounded and maintained in a chamber at 25 ± 3 °C for 72h in the dark, under near 100% relative humidity. The leaf proteins were extracted, ammonium sulfate precipitated, chromatographed on DEAE-cellulose and Phenyl-Sepharose to produce LEF that under SDS-PAGE showed a molecular mass of 44.0 kDa and after N-terminal amino acid analysis a primary sequence composed of AGYTPVLDIGAEVLAAGEPY. The in vivo toxicity of LEF assessed by intraorbital injection in mice showed induced severe uncoordinated movements without death. LEF reduced the muscular contraction in a dose depend way and at 29.8 µg/mL (CE(50)) it produces 50% inhibition of contraction, suggesting that LEF blunts autonomic neurotransmission. Isolated rat kidneys were perfused with LEF and no effects on the perfusion pressure or renal vascular resistance were observed, but urinary flow and glomerular filtration rate increased. Moreover, the percentage of tubular transport of Na(+), K(+) and Cl(-) decreased. Histological examination of the kidneys perfused with LEF exhibited little alterations. These toxic effects observed above were concomitant with the increase of LEF hemagglutination activity, which strongly suggest that one of the toxic principles of I. asarifolia is a lectin present in its leaves.
Assuntos
Ipomoea/toxicidade , Lectinas de Plantas/toxicidade , Sequência de Aminoácidos , Animais , Taxa de Filtração Glomerular/efeitos dos fármacos , Hemaglutinação/efeitos dos fármacos , Ipomoea/química , Rim/efeitos dos fármacos , Rim/patologia , Masculino , Camundongos , Dados de Sequência Molecular , Extratos Vegetais/toxicidade , Folhas de Planta/química , Folhas de Planta/toxicidade , Lectinas de Plantas/química , Lectinas de Plantas/isolamento & purificação , Ratos , Ratos WistarRESUMO
The aim of the present study was to evaluate the potential antinociceptive and toxicity of Canavalia boliviana lectin (CboL) using different methods in mice. The role of carbohydrate-binding sites was also investigated. CboL given to mice daily for 14 days at doses of 5 mg/kg did not cause any observable toxicity. CboL (1, 5, and 10 mg/kg) administered to mice intravenously inhibited abdominal constrictions induced by acetic acid and the two phases of the formalin test. In the hot plate and tail immersion tests, the same treatment of CboL induced significant increase in the latency period. In the hot plate test, the effect of CboL (5 mg/kg) was reversed by naloxone (1 mg/kg), indicating the involvement of the opioid system. In the open-field and rota-rod tests, the CboL treatment did not alter animals' motor function. These results show that CboL presents antinociceptive effects of both central and peripheral origin, involving the participation of the opioid system via lectin domain.
Assuntos
Analgésicos/farmacologia , Canavalia/química , Dor/tratamento farmacológico , Lectinas de Plantas/farmacologia , Analgésicos/administração & dosagem , Analgésicos/toxicidade , Animais , Modelos Animais de Doenças , Relação Dose-Resposta a Droga , Masculino , Camundongos , Medição da Dor , Lectinas de Plantas/administração & dosagem , Lectinas de Plantas/toxicidade , SementesRESUMO
Bauhinia monandra, a plant popularly known as "pata de vaca" in Brazil, is widespread in the world and widely used in folk medicine. BmoLL is a galactose-specific lectin obtained and purified from B. monandra leaves, whose hypoglycemiant potential has been recently demonstrated in rats. The present study was performed to investigate the genotoxic potential of BmoLL in a series of cell-free and bacterial assays. We based our test concentrations on those used in popular medicine. The results showed that lectin BmoLL was unable to produce genotoxicity or cytotoxicity in all the assays used. The results also demonstrated that BmoLL did not increase the frequency of reverse mutation in Salmonella typhimurium strains (TA97, TA98, TA100 and TA102), with and without metabolic activation. However, a significant decrease in the spontaneous mutation frequency was observed in Escherichia coli strains (CC104 and CC104mutMmutY), especially in the repair-deficient strain, suggesting an anti-oxidative potential. B. monandra leaf lectin (BmoLL) did not induce cytotoxic or genotoxic effects in the battery of assays used.
Assuntos
Bauhinia/química , Mutagênicos/toxicidade , Lectinas de Plantas/toxicidade , Animais , Quebras de DNA , DNA Bacteriano/efeitos dos fármacos , Relação Dose-Resposta a Droga , Escherichia coli/efeitos dos fármacos , Escherichia coli/genética , Microssomos Hepáticos/metabolismo , Testes de Mutagenicidade , Extratos Vegetais/metabolismo , Extratos Vegetais/toxicidade , Folhas de Planta/química , Lectinas de Plantas/metabolismo , Plasmídeos/efeitos dos fármacos , Plasmídeos/genética , Ratos , Ratos Sprague-Dawley , Salmonella typhimurium/efeitos dos fármacos , Salmonella typhimurium/genéticaRESUMO
In this study, the cytotoxicity of pouterin in tumorigenic and non-tumorigenic mammalian cell lines was investigated. We found that HeLa, Hep-2 and HT-29 tumor cells were highly sensitive to pouterin cytotoxicity in a dose-dependent manner, whereas non-tumorigenic Vero cells and human lymphocytes were relatively resistant to the protein. Among the tumor cell lines, HeLa cells showed the highest susceptibility to pouterin cytotoxicity, exhibiting a time-dependent increase in LDH leakage and an IC(50) value of 5mug/mL. Morphological alterations such as rounding, cell shrinkage and chromatin condensation, consistent with apoptotic cell death were observed. Apoptosis induction was demonstrated by DNA fragmentation as detected by terminal dUTP nick-end labeling (TUNEL). Furthermore, HeLa cells incubated with pouterin showed disruption of the actin cytoskeleton. Western blot analysis revealed that pouterin caused increased expression of p21, thus indicating cell cycle arrest. Subsequent studies provided evidence that apoptosis may be partially explained in the activation of the tumor necrosis factor receptor 1 (TNFR1) signaling. Interestingly, a time-dependent decrease of the expression of p65 nuclear factor kappa B (NFkappaB) subunit, concomitant with a downregulation of the inhibitor of apoptosis protein 1 (IAP1) was observed, suggesting that TNFR-mediated apoptosis is the predominant pathway induced by pouterin in HeLa cells.
Assuntos
Antineoplásicos Fitogênicos/toxicidade , Apoptose , Citotoxinas/toxicidade , Lectinas de Plantas/toxicidade , Citoesqueleto de Actina/efeitos dos fármacos , Citoesqueleto de Actina/ultraestrutura , Animais , Linhagem Celular Tumoral , Núcleo Celular/efeitos dos fármacos , Núcleo Celular/ultraestrutura , Chlorocebus aethiops , Fragmentação do DNA , Células HeLa , Humanos , Linfócitos/efeitos dos fármacos , Linfócitos/ultraestrutura , NF-kappa B/genética , NF-kappa B/metabolismo , Pouteria/química , Receptores Tipo I de Fatores de Necrose Tumoral/genética , Receptores Tipo I de Fatores de Necrose Tumoral/metabolismo , Transdução de Sinais/efeitos dos fármacos , Regulação para Cima , Células VeroRESUMO
Annona coriacea lectin (ACLEC) was tested for insecticidal activity against larvae of two pyralid moths, Anagasta kuehniella and Corcyra cephalonica. ACLEC produced approximately 50% mortality and mass loss in A. kuehniella larvae when incorporated into an artificial diet at levels of 1.5% and 1.0% (w/w), respectively. In contrast, the inclusion of up to 2% ACLEC in the diet did not significantly decrease the survival or weight of C. cephalonica larvae. The nutritional indices for A. kuehniella and C. cephalonica suggested that ACLEC had a multi-mechanistic mode of action and was an antifeedant for both insects. The toxicity in A. kuehniella apparently resulted from a change in the gut membrane environment and consequent disruption of digestive enzyme recycling mechanisms. Affinity chromatography showed that ACLEC bound to midgut proteins of A. kuehniella and C. cephalonica. However, the 14 kDa subunit of ACLEC was not digested by midgut proteases of A. kuehniella, but was degraded by the corresponding C. cephalonica proteases within a few hours. These findings suggest the possibility of using ACLEC to engineer crop plants.
Assuntos
Controle de Insetos/métodos , Inseticidas/toxicidade , Mariposas/efeitos dos fármacos , Lectinas de Plantas/toxicidade , Animais , Annona , Relação Dose-Resposta a Droga , Ingestão de Alimentos/efeitos dos fármacos , Trato Gastrointestinal/efeitos dos fármacos , Trato Gastrointestinal/metabolismo , Inseticidas/farmacocinética , Larva/efeitos dos fármacos , Larva/crescimento & desenvolvimento , Dose Letal Mediana , Extratos Vegetais/farmacocinética , Extratos Vegetais/toxicidade , Lectinas de Plantas/isolamento & purificação , Lectinas de Plantas/farmacocinética , Sementes/químicaRESUMO
Lectins are carbohydrate binding (glyco)proteins which are ubiquitous in nature. In plants, they are distributed in various families and hence ingested daily in appreciable amounts by both humans and animals. One of the most nutritionally important features of plant lectins is their ability to survive digestion by the gastrointestinal tract of consumers. This allows the lectins to bind to membrane glycosyl groups of the cells lining the digestive tract. As a result of this interaction a series of harmful local and systemic reactions are triggered placing this class of molecules as antinutritive and/or toxic substances. Locally, they can affect the turnover and loss of gut epithelial cells, damage the luminal membranes of the epithelium, interfere with nutrient digestion and absorption, stimulate shifts in the bacterial flora and modulate the immune state of the digestive tract. Systemically, they can disrupt lipid, carbohydrate and protein metabolism, promote enlargement and/or atrophy of key internal organs and tissues and alter the hormonal and immunological status. At high intakes, lectins can seriously threaten the growth and health of consuming animals. They are also detrimental to numerous insect pests of crop plants although less is presently known about their insecticidal mechanisms of action. This current review surveys the recent knowledge on the antinutritional/toxic effects of plant lectins on higher animals and insects.
Assuntos
Fenômenos Fisiológicos da Nutrição Animal , Bactérias/efeitos dos fármacos , Digestão/efeitos dos fármacos , Insetos/efeitos dos fármacos , Lectinas de Plantas/toxicidade , Absorção/efeitos dos fármacos , Animais , Imunidade/efeitos dos fármacos , Inseticidas/toxicidade , Mucosa Intestinal/efeitos dos fármacos , Lectinas de Plantas/metabolismoRESUMO
Hevein (Hev b 6.02) is a major IgE-binding allergen in natural rubber latex and manufactured products. Both tryptophans (Trp(21) and Trp(23)) of the hevein molecule were chemically modified with BNPS-skatole (2-nitrophenylsulfenyl-3-methyl-3(')-bromoindolenine); derivatized allergen failed to significantly inhibit binding of serum IgE in ELISA assays. Similarly, skin prick tests showed that hevein-positive patients gave no response with the modified allergen. Dot blot experiments carried out with anti-hevein mono- and polyclonal antibodies confirmed the importance of Trp(21) and Trp(23) for antibody-recognition, and demonstrated the specific cross-reactivity of other molecules containing hevein-like domains. We also report the structure of Hev b 6.02 at an extended resolution (1.5A) and compare its surface properties around Trp residues with those of similar regions in other allergens. Overall our results indicate that the central part of the protein, which comprises three aromatic and other acidic and polar residues, constitutes a conformational epitope.
Assuntos
Peptídeos Catiônicos Antimicrobianos , Mapeamento de Epitopos/métodos , Epitopos/química , Imunoglobulina E/química , Hipersensibilidade ao Látex/induzido quimicamente , Modelos Moleculares , Lectinas de Plantas/química , Triptofano/química , Alérgenos/química , Alérgenos/imunologia , Alérgenos/toxicidade , Sequência de Aminoácidos , Criança , Pré-Escolar , Simulação por Computador , Cristalografia por Raios X , Humanos , Hipersensibilidade Imediata/induzido quimicamente , Hipersensibilidade Imediata/imunologia , Imunoglobulina E/imunologia , Lactente , Recém-Nascido , Hipersensibilidade ao Látex/imunologia , Dados de Sequência Molecular , Lectinas de Plantas/imunologia , Lectinas de Plantas/toxicidade , Conformação Proteica , Testes Cutâneos , Relação Estrutura-AtividadeRESUMO
A novel lectin from Talisia esculenta seeds (TEL) has recently been purified and characterized. In this study we investigated the proinflammatory activity of TEL in mice using both the air-pouch and peritoneal cavity as well as paw oedema models. TEL (10-40 microg) induced significant neutrophil and mononuclear cell recruitment when injected into either mouse air-pouch or peritoneal cavity. The neutrophil accumulation into the air-pouch was dose- and time-dependent with a maximal response at 16 h, returning to control levels at 72 h whereas maximal mononuclear cell accumulation was observed at 24 h after TEL injection. The same profile of neutrophil accumulation was observed when this lectin was injected into mouse peritoneal cavity, although the maximal mononuclear cell recruitment was observed 48 h after TEL injection. Additionally, TEL (12.5-200 microg/paw) caused a dose-dependent mice paw, as evaluated at 4 h after the lectin injection. D-mannose, better than D-glucose, significantly inhibited TEL-induced neutrophil migration into the peritoneal cavity or air-pouch. D-galactose had no effect on TEL-induced neutrophil migration in either cavity studied. On the other hand, D-mannose slightly inhibited the TEL-induced paw oedema, whereas neither D-glucose nor D-galactose affected this phenomenon. In conclusion, our data show that TEL induces neutrophil and mononuclear cell accumulation by a mechanism related to their specific sugar-binding properties.
Assuntos
Inflamação/induzido quimicamente , Inflamação/imunologia , Leucócitos Mononucleares/efeitos dos fármacos , Leucócitos Mononucleares/imunologia , Neutrófilos/imunologia , Lectinas de Plantas/toxicidade , Análise de Variância , Animais , Carboidratos/imunologia , Quimiotaxia de Leucócito/imunologia , Relação Dose-Resposta Imunológica , Edema/induzido quimicamente , Edema/imunologia , Camundongos , Cavidade Peritoneal/citologia , Lectinas de Plantas/imunologia , Sapindaceae/química , Sementes/químicaRESUMO
Lectins are proteins or glycoproteins known for their ability to agglutinate cells, especially erythrocytes. Several lectins are toxic to mammalian cells both in vitro and in vivo, inhibit growth when incorporated into the diet and are toxic when injected into animals. On the other hand, the use of lectins has been suggested as an alternative in cancer treatment. The objective of the present study was to evaluate the acute toxicity of a lectin extracted and purified from tepary bean (Phaseolus acutifolius, G-400-34) on CD-1 mice. Fetuin affinity chromatography, electrophoretic pattern and Western-immunoblot techniques were used to purify and partially characterize the lectin. This tepary bean line presented high levels of lectin activity. Western blot revealed that the sera reacted with the known PHA subunits in the 34-40 kD range. Four major lectin and lectin-related glycopolypeptides were identified. The purified lectin from tepary bean was a tetrameric one that ran at about 115-120 kD. The LD(50) (ip) was 1100 mg/kg body weight for males and 1120 mg/kg body weight for females. The body weight of experimental animals decreased in a dose-dependent manner. The main target organs affected were small intestine, spleen and thymus. The lectin isolated from tepary bean showed affinity towards fetuin, with high agglutination values and low acute toxicity.