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1.
FASEB J ; 35(6): e21640, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-33991130

RESUMO

Certain species of pathogenic bacteria damage tissues by secreting cholesterol-dependent cytolysins, which form pores in the plasma membranes of animal cells. However, reducing cholesterol protects cells against these cytolysins. As the first committed step of cholesterol biosynthesis is catalyzed by squalene synthase, we explored whether inhibiting this enzyme protected cells against cholesterol-dependent cytolysins. We first synthesized 22 different nitrogen-containing bisphosphonate molecules that were designed to inhibit squalene synthase. Squalene synthase inhibition was quantified using a cell-free enzyme assay, and validated by computer modeling of bisphosphonate molecules binding to squalene synthase. The bisphosphonates were then screened for their ability to protect HeLa cells against the damage caused by the cholesterol-dependent cytolysin, pyolysin. The most effective bisphosphonate reduced pyolysin-induced leakage of lactate dehydrogenase into cell supernatants by >80%, and reduced pyolysin-induced cytolysis from >75% to <25%. In addition, this bisphosphonate reduced pyolysin-induced leakage of potassium from cells, limited changes in the cytoskeleton, prevented mitogen-activated protein kinases cell stress responses, and reduced cellular cholesterol. The bisphosphonate also protected cells against another cholesterol-dependent cytolysin, streptolysin O, and protected lung epithelial cells and primary dermal fibroblasts against cytolysis. Our findings imply that treatment with bisphosphonates that inhibit squalene synthase might help protect tissues against pathogenic bacteria that secrete cholesterol-dependent cytolysins.


Assuntos
Colesterol/metabolismo , Citotoxinas/efeitos adversos , Difosfonatos/farmacologia , Inibidores Enzimáticos/farmacologia , Farnesil-Difosfato Farnesiltransferase/antagonistas & inibidores , Fibroblastos/citologia , Substâncias Protetoras/farmacologia , Células A549 , Proteínas de Bactérias/efeitos adversos , Toxinas Bacterianas/efeitos adversos , Proliferação de Células , Fibroblastos/efeitos dos fármacos , Fibroblastos/patologia , Células HeLa , Proteínas Hemolisinas/efeitos adversos , Humanos , Estreptolisinas/efeitos adversos
2.
Arch Insect Biochem Physiol ; 103(4): e21638, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31702074

RESUMO

Clostera anachoreta is one of the important Lepidoptera insect pests in forestry, especially in poplars woods in China, Europe, Japan, and India, and so forth, and also the target insect of Cry1Ac toxin and Bt plants. Six genes, HSC70, GNB2L/RACK1, PNLIP, BI1-like, arylphorin type 2, and PKM were found in this study, and they might be associated with the response to the Cry1Ac toxin, found by analyzing the transcriptome data. And the PI3K-Akt pathway was highly enriched in differentially expressed unigenes and linked to several crucial pathways, including the B-cell receptor signaling pathway, toll-like receptor pathway, and mitogen-activated protein kinase signaling pathway. They might be involved in the recovery stage of the damaged midgut during the response to sublethal doses of Cry1Ac toxin. This is the first study conducted to specifically investigate C. anachoreta response to Cry toxin stress using large-scale sequencing technologies, and the results highlighted some important genes and pathways that could be involved in Btcry1Ac resistance development or could serve as targets for biologically based control mechanisms of this insect pest.


Assuntos
Proteínas de Bactérias/efeitos adversos , Endotoxinas/efeitos adversos , Proteínas Hemolisinas/efeitos adversos , Resistência a Inseticidas/genética , Mariposas/genética , Transcriptoma , Animais , Bacillus thuringiensis/química , Toxinas de Bacillus thuringiensis , China , Trato Gastrointestinal/metabolismo , Perfilação da Expressão Gênica , Larva/efeitos dos fármacos , Larva/genética , Larva/crescimento & desenvolvimento , Larva/metabolismo , Mariposas/efeitos dos fármacos , Mariposas/crescimento & desenvolvimento , Mariposas/metabolismo
3.
Front Immunol ; 9: 951, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29867940

RESUMO

Staphylococcus aureus alpha-toxin and Panton-Valentine leukocidin (PVL) have been reported to play critical roles in different animal models of skin infection. These models, however, do not completely recapitulate the human disease due to the host specificity of these toxins as well as the intrinsic anatomical and immunological differences between animals and humans. Human skin explants represent a valid alternative to animal models for studying skin infections. Herein, we developed a human skin explant wound model to study the pathogenic role of alpha-toxin and PVL; inflammatory responses elicited by these toxins; and the neutralizing ability of antibodies to mitigate skin damage. Different concentrations of alpha-toxin and/PVL were applied to superficial wounds on human skin explants. Treatment with alpha-toxin resulted in high tissue toxicity and loss of skin epithelial integrity. PVL induced a milder but significant toxicity with no loss of skin structural integrity. The combination of both toxins resulted in increased tissue toxicity as compared with the individual toxins alone. Treatment of the skin with these toxins also resulted in a decrease of CD45-positive cells in the epidermis. In addition, both toxins induced the release of pro-inflammatory cytokines and chemokines. Finally, antibodies raised against alpha-toxin were able to mitigate tissue toxicity in a concentration-dependent manner. Results from this study confirm the key role of α-toxin in staphylococcal infection of the human skin and suggest a possible cooperation of the two toxins in tissue pathology.


Assuntos
Toxinas Bacterianas/efeitos adversos , Exotoxinas/efeitos adversos , Proteínas Hemolisinas/efeitos adversos , Leucocidinas/efeitos adversos , Pele/microbiologia , Infecções Cutâneas Estafilocócicas/microbiologia , Anticorpos Monoclonais/farmacologia , Toxinas Bacterianas/antagonistas & inibidores , Citocinas/metabolismo , Proteínas Hemolisinas/antagonistas & inibidores , Humanos , Imuno-Histoquímica , Mediadores da Inflamação/metabolismo , Lactato Desidrogenases/metabolismo , Antígenos Comuns de Leucócito/metabolismo , Proteínas Recombinantes/efeitos adversos , Pele/metabolismo , Pele/patologia , Infecções Cutâneas Estafilocócicas/metabolismo , Infecções Cutâneas Estafilocócicas/patologia , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/patogenicidade
4.
Int J Gynecol Cancer ; 28(4): 764-772, 2018 05.
Artigo em Inglês | MEDLINE | ID: mdl-29538258

RESUMO

OBJECTIVES: A global unmet medical need exists for effective treatments for persistent, recurrent, or metastatic cervical cancer, as patients have a short life expectancy. Recently, immunotherapies have shown promising survival benefits for patients with advanced forms of cancer. Axalimogene filolisbac (ADXS11-001), a Listeria monocytogenes immunotherapy with a broad effect on the immune system, is under investigation for treatment of human papillomavirus-associated cancers including cervical cancer. METHODS: This phase 2 study evaluated the safety and efficacy of ADXS11-001, administered with or without cisplatin, in patients with recurrent/refractory cervical cancer following prior chemotherapy and/or radiotherapy. A total of 109 patients were treated, and 69 were evaluable for tumor response at equal to or more than 3 months postbaseline. RESULTS: Median overall survival (OS) was comparable between treatment groups (ADXS11-001: 8.28 months; 95% confidence interval [CI], 5.85-10.5 months; ADXS11-001 + cisplatin: 8.78 months; 95% CI, 7.4-13.3 months). The 12- and 18-month milestone OS rates were 30.9% versus 38.9%, and 23.6% versus 25.9% for each group, respectively (34.9% and 24.8% combined). Median progression-free survival (6.10 vs 6.08 months) and the overall response rate (17.1% vs 14.7%) were similar for both groups. ADXS11-001 was generally well tolerated; adverse events were predominantly mild to moderate in severity and not related to treatment. More adverse events were reported in the combination group (429 vs 275). CONCLUSIONS: These promising safety and efficacy results, including the encouraging 12-month 34.9% combined OS rate, warrant further investigation of ADXS11-001 for treatment of recurrent/refractory cervical cancer.


Assuntos
Toxinas Bacterianas/uso terapêutico , Proteínas de Choque Térmico/uso terapêutico , Proteínas Hemolisinas/uso terapêutico , Imunoterapia , Neoplasias do Colo do Útero/terapia , Adulto , Idoso , Antineoplásicos/uso terapêutico , Toxinas Bacterianas/efeitos adversos , Cisplatino/uso terapêutico , Feminino , Proteínas de Choque Térmico/efeitos adversos , Proteínas Hemolisinas/efeitos adversos , Humanos , Pessoa de Meia-Idade
5.
Pest Manag Sci ; 74(8): 1854-1860, 2018 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-29427309

RESUMO

BACKGROUND: Honeydew is a sugar-rich excretion produced by sap-feeding Sternorrhyncha and is an important source of carbohydrates for natural enemies, especially for parasitoids. Honeydew derived from genetically modified (GM) crops can contain amounts of the transgene product. Thus, it is a possible route of exposure for natural enemies feeding on honeydew. In the present study, the potential effects of Nilaparvata lugens honeydew derived from Cry1C and Cry2A rice on different life-table parameters and parasitism dynamics of the egg parasitoid Anagrus nilaparvatae were evaluated under laboratory and field conditions. Furthermore, the Bacillus thuringiensis (Bt) levels and the sugar and amino acid composition of honeydew were analyzed. RESULTS: Results indicated that A. nilaparvatae was exposed to Bt proteins by feeding on N. lugens honeydew produced from Bt rice. However, honeydew derived from the tested Cry1C and Cry2A rice lines did not affect the development, longevity, emergence rate and fecundity of A. nilaparvatae. Also, the parasitism dynamics in the field remained unaffected. In addition, the sugar and amino acid composition of N. lugens honeydew was not significantly altered for the tested Bt rice lines compared with the parental non-Bt plant. CONCLUSION: The quality of honeydew derived from the tested Bt rice lines as a food resource for natural enemies was maintained. © 2018 Society of Chemical Industry.


Assuntos
Proteínas de Bactérias/efeitos adversos , Endotoxinas/efeitos adversos , Hemípteros/parasitologia , Proteínas Hemolisinas/efeitos adversos , Interações Hospedeiro-Parasita , Inseticidas/efeitos adversos , Oryza/química , Vespas/fisiologia , Aminoácidos/química , Animais , Toxinas de Bacillus thuringiensis , Dieta , Tábuas de Vida , Plantas Geneticamente Modificadas/química , Açúcares/química
6.
J Econ Entomol ; 111(1): 218-226, 2018 02 09.
Artigo em Inglês | MEDLINE | ID: mdl-29329399

RESUMO

In this study, we constructed crop life tables for Bacillus thuringiensis Berliner (Bt) Cry1Ab and non-Bt corn hybrids, in which yield-loss factors and abundance of predaceous arthropods were recorded during 2 yr at two locations. Corn kernel/grain was the yield component that had the heaviest losses and that determined the overall yield loss in the corn hybrids across years and locations. Yield losses in both corn hybrids were primarily caused by kernel-destroying insects. Helicoverpa zea (Boddie) and Spodoptera frugiperda (Smith) (Lepidoptera: Noctuidae) were the key loss factors at one location, while at the other, the key loss factor was the silk fly larvae, Euxesta spp. (Diptera: Ulidiidae). Although the realized yield of corn grains was not different (P > 0.05) between Cry1Ab and non-Bt corn hybrids, the Bt corn hybrid reduced (P < 0.05) the damage by H. zea and S. frugiperda in three of the four field trials, particularly at the location where Lepidoptera were the key loss factors. As expected, no reduction in the abundance of predaceous arthropods was observed in Cry1Ab corn fields. Various species of natural enemies were recorded, particularly the earwig Doru luteipes (Scudder) (Dermaptera: Forficulidae), which was the most abundant and frequent predaceous insect. These results indicate that integration of pest management practices should be pursued to effectively minimize losses by kernel-destroying insects during corn reproductive stages when growing non-Bt or certain low-dose Bt corn cultivars for fall armyworm and corn earworm, such as those producing Cry1Ab or other Cry toxins.


Assuntos
Proteínas de Bactérias/farmacologia , Endotoxinas/farmacologia , Proteínas Hemolisinas/farmacologia , Herbivoria/efeitos dos fármacos , Inseticidas/farmacologia , Mariposas/efeitos dos fármacos , Comportamento Predatório , Zea mays/crescimento & desenvolvimento , Animais , Artrópodes , Toxinas de Bacillus thuringiensis , Proteínas de Bactérias/efeitos adversos , Brasil , Dípteros/efeitos dos fármacos , Dípteros/crescimento & desenvolvimento , Endotoxinas/efeitos adversos , Proteínas Hemolisinas/efeitos adversos , Inseticidas/efeitos adversos , Larva/efeitos dos fármacos , Tábuas de Vida , Mariposas/crescimento & desenvolvimento , Controle Biológico de Vetores , Plantas Geneticamente Modificadas/crescimento & desenvolvimento
7.
Environ Entomol ; 46(2): 413-417, 2017 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-28334097

RESUMO

Previous studies into third trophic level exposure of Chrysoperla spp. (Neuroptera: Chrysopidae) to Cry1Ab proteins produced by Bt crops yielded contradicting results. These contradictions were largely ascribed to differences in prey quality and exposure methods. In this study, we used healthy prey to expose lacewing larvae to Cry1Ab protein produced by Bt maize, and also determined the concentration of this protein at different trophic levels. Experiments were conducted in which Chrysoperla pudica (Navás) larvae were fed different diets which included aphids and healthy Bt-resistant Busseola fusca (Fuller) (Lepidoptera: Noctuidae) larvae feeding on Bt maize tissue. Lacewing larval and pupal development times as well as overall mortality were determined. The concentration of Cry1Ab protein in B. fusca larvae were fourfold reduced compared with that in leaf tissue and was below detection level in lacewing larvae. Survival to the pupal stage was higher than 96% in all treatments. Larval and pupal development periods did not differ significantly between treatments in which prey fed on Bt or non-Bt maize. This study showed feeding on healthy prey that consumed Cry1Ab protein has no adverse effect on the biology of C. pudica.


Assuntos
Bacillus thuringiensis/química , Proteínas de Bactérias/efeitos adversos , Endotoxinas/efeitos adversos , Proteínas Hemolisinas/efeitos adversos , Insetos/efeitos dos fármacos , Controle Biológico de Vetores , Plantas Geneticamente Modificadas/efeitos adversos , Zea mays/química , Animais , Afídeos/química , Bacillus thuringiensis/genética , Toxinas de Bacillus thuringiensis , Dieta , Insetos/crescimento & desenvolvimento , Larva/química , Larva/efeitos dos fármacos , Larva/crescimento & desenvolvimento , Mariposas/química , Plantas Geneticamente Modificadas/química , Pupa/efeitos dos fármacos , Pupa/crescimento & desenvolvimento , Zea mays/genética
8.
Sci Transl Med ; 8(329): 329ra31, 2016 Mar 09.
Artigo em Inglês | MEDLINE | ID: mdl-26962155

RESUMO

Broad-spectrum antibiotic use may adversely affect a patient's beneficial microbiome and fuel cross-species spread of drug resistance. Although alternative pathogen-specific approaches are rationally justified, a major concern for this precision medicine strategy is that co-colonizing or co-infecting opportunistic bacteria may still cause serious disease. In a mixed-pathogen lung infection model, we find that the Staphylococcus aureus virulence factor α toxin potentiates Gram-negative bacterial proliferation, systemic spread, and lethality by preventing acidification of bacteria-containing macrophage phagosomes, thereby reducing effective killing of both S. aureus and Gram-negative bacteria. Prophylaxis or early treatment with a single α toxin neutralizing monoclonal antibody prevented proliferation of co-infecting Gram-negative pathogens and lethality while also promoting S. aureus clearance. These studies suggest that some pathogen-specific, antibody-based approaches may also work to reduce infection risk in patients colonized or co-infected with S. aureus and disparate drug-resistant Gram-negative bacterial opportunists.


Assuntos
Toxinas Bacterianas/efeitos adversos , Proteínas Hemolisinas/efeitos adversos , Infecções Oportunistas/microbiologia , Infecções Respiratórias/microbiologia , Infecções Estafilocócicas/microbiologia , Ácidos/metabolismo , Animais , Anticorpos Antibacterianos/imunologia , Anticorpos Monoclonais/imunologia , Calpaína/metabolismo , Coinfecção/microbiologia , Ativação Enzimática/efeitos dos fármacos , Humanos , Células Matadoras Naturais/efeitos dos fármacos , Células Matadoras Naturais/patologia , Lisossomos/metabolismo , Macrófagos Alveolares/efeitos dos fármacos , Macrófagos Alveolares/patologia , Camundongos , Viabilidade Microbiana/efeitos dos fármacos , Modelos Biológicos , Neutrófilos/efeitos dos fármacos , Neutrófilos/patologia , Infecções Oportunistas/patologia , Pneumonia/microbiologia , Pneumonia/patologia , Pseudomonas aeruginosa/efeitos dos fármacos , Infecções Respiratórias/patologia , Infecções Estafilocócicas/patologia , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/crescimento & desenvolvimento
9.
Biochemistry ; 55(17): 2510-7, 2016 05 03.
Artigo em Inglês | MEDLINE | ID: mdl-27015018

RESUMO

ß-Toxin is an important virulence factor of Staphylococcus aureus, contributing to colonization and development of disease [Salgado-Pabon, W., et al. (2014) J. Infect. Dis. 210, 784-792; Huseby, M. J., et al. (2010) Proc. Natl. Acad. Sci. U.S.A. 107, 14407-14412; Katayama, Y., et al. (2013) J. Bacteriol. 195, 1194-1203]. This cytotoxin has two distinct mechanisms of action: sphingomyelinase activity and DNA biofilm ligase activity. However, the distinct mechanism that is most important for its role in infective endocarditis is unknown. We characterized the active site of ß-toxin DNA biofilm ligase activity by examining deficiencies in site-directed mutants through in vitro DNA precipitation and biofilm formation assays. Possible conformational changes in mutant structure compared to that of wild-type toxin were assessed preliminarily by trypsin digestion analysis, retention of sphingomyelinase activity, and predicted structures based on the native toxin structure. We addressed the contribution of each mechanism of action to producing infective endocarditis and sepsis in vivo in a rabbit model. The H289N ß-toxin mutant, lacking sphingomyelinase activity, exhibited lower sepsis lethality and infective endocarditis vegetation formation compared to those of the wild-type toxin. ß-Toxin mutants with disrupted biofilm ligase activity did not exhibit decreased sepsis lethality but were deficient in infective endocarditis vegetation formation compared to the wild-type protein. Our study begins to characterize the DNA biofilm ligase active site of ß-toxin and suggests ß-toxin functions importantly in infective endocarditis through both of its mechanisms of action.


Assuntos
Toxinas Bacterianas/efeitos adversos , Biofilmes/efeitos dos fármacos , Endocardite/etiologia , Proteínas Hemolisinas/efeitos adversos , Ligases/deficiência , Sepse/etiologia , Esfingomielina Fosfodiesterase/deficiência , Staphylococcus aureus/enzimologia , Sequência de Aminoácidos , Animais , Toxinas Bacterianas/química , Toxinas Bacterianas/genética , Toxinas Bacterianas/metabolismo , Biofilmes/crescimento & desenvolvimento , Endocardite/enzimologia , Endocardite/patologia , Feminino , Proteínas Hemolisinas/química , Proteínas Hemolisinas/genética , Proteínas Hemolisinas/metabolismo , Masculino , Conformação Proteica , Coelhos , Sepse/enzimologia , Sepse/patologia , Esfingomielina Fosfodiesterase/efeitos adversos , Esfingomielina Fosfodiesterase/química , Esfingomielina Fosfodiesterase/genética , Esfingomielina Fosfodiesterase/metabolismo , Infecções Estafilocócicas/complicações , Infecções Estafilocócicas/microbiologia , Staphylococcus aureus/genética
10.
Environ Entomol ; 45(2): 518-25, 2016 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-26721297

RESUMO

The ecological risks to nontarget organisms should be rigorously assessed before Bt crops are released. Here, the impacts of a new Cry1Ab/Vip3H rice line on arthropod communities in rice agroecosystems were evaluated across 3 yr. Arthropods collected via vacuum were sorted into five guilds. The abundance and proportion of each guild as well as community-level parameters were determined in Cry1Ab/Vip3H and control rice fields. Changes in arthropod species assemblage over sampling dates were investigated by principal response curves (PRCs). Cry1Ab/Vip3H rice did not exert significant impacts on the seasonal density and proportion of each guild, except parasitoids. Detritivore seasonal density, but not its relative abundance, was significantly affected by Cry1Ab/Vip3H rice. Four community indices (species richness S, Shannon-Wiener index H', Simpson index D, and evenness index J') were similar between rice types. PRCs revealed a slight community difference between rice types in the past two tested years, with rice types accounting for 1.0-3.5% of the variance among arthropod communities. However, sampling dates explain 32.1-67.6% for these community differences. Of the 46 taxa with higher species weights, 26.1% of the taxa were significantly different, including seven taxa with higher abundance and five with lower density in Cry1Ab/Vip3H rice fields. These differences may be attributed to change in abundance of prey or hosts but not to direct effects of Bt proteins. We infer that this new Cry1Ab/Vip3H rice line poses no unintended ecological risks to the arthropod community.


Assuntos
Artrópodes/efeitos dos fármacos , Proteínas de Bactérias/efeitos adversos , Biodiversidade , Endotoxinas/efeitos adversos , Proteínas Hemolisinas/efeitos adversos , Inseticidas/efeitos adversos , Oryza/fisiologia , Controle Biológico de Vetores , Animais , Toxinas de Bacillus thuringiensis , Proteínas de Bactérias/genética , Proteínas de Bactérias/farmacologia , China , Endotoxinas/genética , Endotoxinas/farmacologia , Proteínas Hemolisinas/genética , Proteínas Hemolisinas/farmacologia , Inseticidas/farmacologia , Oryza/genética , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/fisiologia
11.
Transgenic Res ; 25(2): 163-72, 2016 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-26581349

RESUMO

Numerous genetically modified (GM) crops expressing proteins for insect resistance have been commercialized following extensive testing demonstrating that the foods obtained from them are as safe as that obtained from their corresponding non-GM varieties. In this paper, we report the outcome of safety studies conducted on a newly developed insect-resistant GM rice expressing the cry2A* gene by a subchronic oral toxicity study on rats. GM rice and non-GM rice were incorporated into the diet at levels of 30, 50, and 70% (w/w), No treatment-related adverse or toxic effects were observed based on an examination of the daily clinical signs, body weight, food consumption, hematology, serum biochemistry, and organ weight or based on gross and histopathological examination. These results demonstrate that the GM rice with cry2A* gene is as safe for food as conventional non-GM rice.


Assuntos
Proteínas de Bactérias/genética , Endotoxinas/genética , Análise de Alimentos , Proteínas Hemolisinas/genética , Oryza/genética , Plantas Geneticamente Modificadas/genética , Animais , Toxinas de Bacillus thuringiensis , Proteínas de Bactérias/administração & dosagem , Proteínas de Bactérias/efeitos adversos , Peso Corporal/genética , Endotoxinas/administração & dosagem , Endotoxinas/efeitos adversos , Proteínas Hemolisinas/administração & dosagem , Proteínas Hemolisinas/efeitos adversos , Humanos , Lepidópteros/genética , Lepidópteros/patogenicidade , Oryza/efeitos adversos , Oryza/crescimento & desenvolvimento , Plantas Geneticamente Modificadas/efeitos adversos , Plantas Geneticamente Modificadas/crescimento & desenvolvimento , Ratos
12.
Food Chem Toxicol ; 81: 81-91, 2015 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-25890087

RESUMO

Cry8Ka5 is a mutant protein from Bacillus thuringiensis (Bt) that has been proposed for developing transgenic plants due to promising activity against coleopterans, like Anthonomus grandis (the major pest of Brazilian cotton culture). Thus, an early food safety assessment of Cry8Ka5 protein could provide valuable information to support its use as a harmless biotechnological tool. This study aimed to evaluate the food safety of Cry8Ka5 protein following the two-tiered approach, based on weights of evidence, proposed by ILSI. Cry1Ac protein was used as a control Bt protein. The history of safe use revealed no convincing hazard reports for Bt pesticides and three-domain Cry proteins. The bioinformatics analysis with the primary amino acids sequence of Cry8Ka5 showed no similarity to any known toxic, antinutritional or allergenic proteins. The mode of action of Cry proteins is well understood and their fine specificity is restricted to insects. Cry8Ka5 and Cry1Ac proteins were rapidly degraded in simulated gastric fluid, but were resistant to simulated intestinal fluid and heat treatment. The LD50 for Cry8Ka5 and Cry1Ac was >5000 mg/kg body weight when administered by gavage in mice. Thus, no expected relevant risks are associated with the consumption of Cry8Ka5 protein.


Assuntos
Proteínas de Bactérias/efeitos adversos , Endotoxinas/efeitos adversos , Inocuidade dos Alimentos , Proteínas Hemolisinas/efeitos adversos , Proteínas Mutantes/efeitos adversos , Testes de Toxicidade Aguda/métodos , Alanina Transaminase/sangue , Fosfatase Alcalina/sangue , Sequência de Aminoácidos , Animais , Aspartato Aminotransferases/sangue , Bacillus thuringiensis/genética , Toxinas de Bacillus thuringiensis , Proteínas de Bactérias/genética , Contagem de Células Sanguíneas , Colesterol/sangue , Biologia Computacional , Creatinina/sangue , Endotoxinas/genética , Feminino , Proteínas Hemolisinas/genética , Insetos , Inseticidas , Dose Letal Mediana , Camundongos , Dados de Sequência Molecular , Proteínas Mutantes/genética , Tamanho do Órgão/efeitos dos fármacos , Controle Biológico de Vetores , Plantas Geneticamente Modificadas/genética , Triglicerídeos/sangue , Ureia/sangue
13.
Environ Entomol ; 42(1): 173-80, 2013 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-23339799

RESUMO

As a key component of ecological risk assessments, nontarget effects of Bacillus thuringiensis (Bt) rice have been tested under laboratory and field conditions for various organisms. A 2-yr field experiment was conducted to observe the nontarget effects of six transgenic rice lines (expressing the Cry1Ab or fused protein of Cry1Ab and Cry1Ac) on four nontarget thrips species including Frankliniella intonsa (Trybom), F. tenuicornis (Uzel), Haplothrips aculeatus (F.), and H. tritici (Kurd), as compared with their rice parental control lines. Two sampling methods including the beat plate and plastic bag method were used to monitor the population densities of the four thrips species for 2 yr. The results showed that the seasonal average densities of four tested thrips species in Bt rice plots were significantly lower than or very similar to those in the non-Bt rice plots depending on rice genotypes, sampling methods, and years. Among all six tested Bt rice lines, transgenic B1 and KMD2 lines suppressed the population of these tested thrips species the most. Our results indicate that the tested Bt rice lines are unlikely to result in high population pressure of thrips species in comparison with non-Bt rice. In some cases, Bt rice lines could significantly suppress thrips populations in the rice ecosystem. In addition, compatibility of Bt rice, with rice host plant resistance to nontarget sucking pests is also discussed within an overall integrated pest management program for rice.


Assuntos
Proteínas de Bactérias/efeitos adversos , Endotoxinas/efeitos adversos , Proteínas Hemolisinas/efeitos adversos , Oryza/genética , Plantas Geneticamente Modificadas/efeitos adversos , Tisanópteros , Animais , Toxinas de Bacillus thuringiensis , Proteínas de Bactérias/genética , Endotoxinas/genética , Proteínas Hemolisinas/genética , Herbivoria , Densidade Demográfica , Estações do Ano
14.
J Surg Res ; 179(1): e167-75, 2013 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-22482762

RESUMO

BACKGROUND: Sepsis and systemic inflammatory response syndrome (SIRS) continue to represent critical conditions with persistently high mortality and continue to need experimental and clinical research. We developed a rat model of gram-positive and gram-negative SIRS/sepsis with in vivo visualization of the pulmonary microcirculation to evaluate the optimal dosage and application path for SIRS/sepsis-inducing agents. METHODS: Male Sprague-Dawley rats (n = 8 per group) were assigned to control, lipopolysaccharide (LPS), alphatoxin, or living Staphylococcus aureus (strain 68/50) groups. SIRS/sepsis was induced by intraperitoneal injection of the differing agents. The onset of SIRS was determined through human sepsis parameters and fluorescence video microscopy-based measurement of platelet and leukocyte velocity within the pulmonary vascular system (injection of 5 × 10(6) calcein AM-labeled nonactivated platelets; leukocytes labeled in vivo by rhodamine). RESULTS: The optimal dosage to induce SIRS was 30 mg/250 g body weight for LPS (bolus injection) and 60 µg/250 g body weight for alphatoxin (2 h continuous perfusion). Sepsis was not achieved by injection of living S. aureus. The onset of SIRS was seen after 2-5 h for LPS and after 2-4 h for alphatoxin after intraperitoneal administration with a significantly increased heart rate, breathing rate, and body temperature (P < 0.05) and significantly decreased cell velocity (P < 0.05). CONCLUSION: Our study represents an effective approach for a gram-negative (LPS) and gram-positive (alphatoxin) SIRS model to mimic human sepsis. Human sepsis-based criteria were used to define SIRS in our rats to achieve an optimal analogy for the human system. In our model, higher dosages were needed for SIRS induction than have been previously reported. The resulting, considerable heterogeneity of current SIRS-inducing models suggests that additional studies in this field are required to define standard procedures.


Assuntos
Modelos Animais de Doenças , Sepse/etiologia , Sepse/fisiopatologia , Síndrome de Resposta Inflamatória Sistêmica/etiologia , Síndrome de Resposta Inflamatória Sistêmica/fisiopatologia , Animais , Toxinas Bacterianas/administração & dosagem , Toxinas Bacterianas/efeitos adversos , Hemodinâmica/fisiologia , Proteínas Hemolisinas/administração & dosagem , Proteínas Hemolisinas/efeitos adversos , Humanos , Injeções Intraperitoneais , Lipopolissacarídeos/administração & dosagem , Lipopolissacarídeos/efeitos adversos , Pulmão/irrigação sanguínea , Pulmão/fisiopatologia , Masculino , Microcirculação/fisiologia , Microscopia de Vídeo , Ratos , Ratos Sprague-Dawley , Respiração , Sepse/sangue , Síndrome de Resposta Inflamatória Sistêmica/sangue
15.
Ying Yong Sheng Tai Xue Bao ; 24(9): 2685-90, 2013 Sep.
Artigo em Chinês | MEDLINE | ID: mdl-24417130

RESUMO

The worldwide cultivation of transgenic crops not only provides tremendous economic benefits, but also induces the concern about the potential risks of transgenic crops on soil ecosystem in which microorganisms are involved. The potential effects of transgenic crops on soil microorganisms include the direct effects of the transgenic proteins on non-target soil microorganisms, and the indirect effects of the unintentional changes in the chemical compositions of root exudates induced by the introduction of the exogenous transgenic proteins. Most of the studies on transgenic crops suggested that transgenic crops could affect the quantity and structure of soil microbial populations. However, the perceivable effects on the soil microorganisms are inconsistent, with some in significant and others in non-significant, or some with persistent and others with non-persistent. This paper summarized the effects of different transgenic crops on soil microorganisms, and discussed the factors affecting the assessment reliability, including the species of transgenic crops and the experimental technologies and principles. Some issues needed to be paid special attention to in the future studies were put forward.


Assuntos
Produtos Agrícolas/genética , Ecossistema , Plantas Geneticamente Modificadas/crescimento & desenvolvimento , Microbiologia do Solo , Toxinas de Bacillus thuringiensis , Proteínas de Bactérias/efeitos adversos , Produtos Agrícolas/crescimento & desenvolvimento , Endotoxinas/efeitos adversos , Gossypium/genética , Gossypium/crescimento & desenvolvimento , Proteínas Hemolisinas/efeitos adversos , Medição de Risco
16.
Arh Hig Rada Toksikol ; 63(4): 545-9, 2012 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-23334050

RESUMO

Building associated illnesses - sick building syndrome (SBS) as a common example - are associated with staying in buildings with poor indoor air quality. The importance of indoor fungal growth in this phenomenon continues to be evident, even though no causative relation has been established so far. Indoor humidity is strongly associated with the symptoms of SBS. Fungal metabolites that may induce ill health in susceptible occupants comprise beta-D-glucan, mycotoxins, and volatile organic compounds as known irritants and/or immunomodulators. Indoor toxic fungal metabolites might be located in micromycetal propagules (endometabolites), in (bio-)aerosol, detritus, and house dust (exometabolites) as their particular carriers. It is highly probable that hyphal fragments, dust, and particles able to reach the alveoli have the strongest depository and toxic potential. Most fungal spores are entrapped by the upper respiratory tract and do not reach further than the bronchi because of their size, morphology, and the mode of propagation (such as slime heads and aggreggation). This is why studies of the toxic effects of fungal spores prefer directly applying metabolite mixtures over mimicking real exposure. Chronic low-level exposure to a mixture of fungal toxicants and other indoor stressors may have synergistic effects and lead to severe neuroendocrineimmune changes.


Assuntos
Poluição do Ar em Ambientes Fechados/efeitos adversos , Poeira/análise , Fungos/isolamento & purificação , Micotoxinas/efeitos adversos , Material Particulado/efeitos adversos , Material Particulado/análise , Síndrome do Edifício Doente/etiologia , Proteínas Hemolisinas/efeitos adversos , Proteínas Hemolisinas/análise , Humanos , Micotoxinas/análise
17.
Yi Chuan ; 33(5): 443-8, 2011 May.
Artigo em Chinês | MEDLINE | ID: mdl-21586391

RESUMO

With the large scale cultivation of transgenic crops expressing Bacillus thuringiensis (Bt) insecticidal crystal proteins in the world, the problem of environmental safety caused by these Bt crops has received extensive attention. These insecticidal crystal proteins can be released into the soil continuously in the growing period of Bt plants. If their accumulation of the insecticidal crystal proteins exceeds consumption by insect larvae and degradation by the environmental factors, these insecticidal crystal proteins could constitute a hazard to non-target insects and soil microbiota. There are three main ways to release insecticidal crystal proteins into soil for Bt plants: root exudates, pollen falling, and crop reside returning. The Bt insecticidal crystal proteins released into soil can be adsorbed rapidly by active soil particles and the absorption equilibrium attained within 1-3 h. The adsorption protects Bt insecticidal crystal proteins against soil microbial degradation or enzyme degradation, which leads to remarkable prolong of the persistence of insecticidal activity. The change of soil microorganism species is an important index for evaluating the effect of Bt plants on soil ecology. The research showed that these insecticidal crystal proteins released by the Bt plant root exudates or Bt organism had no toxicity to the soil earthworms, nematodes, protozoa, bacteria and fungi; however, it could reduce the mycelium length of the arbuscular mycorrhizal fungi (AMF) and restrain AMF to form invasion unit. The influencing degree of Bt protein on soil enzyme activity varied with the releasing modes or growth period of Bt crops. Bt Cry1Ab protein can be taken up from soil by parts of following crops; however, different results were obtained with different commercial kits. To better understand the soil ecological evaluation about the insecticidal crystal proteins released from transgenic Bt crops, this review provides a comprehensive overview about the release, adsorption and residue of Bt insecticidal crystal proteins in soil, as well as their effects on soil protozoa, soil microorganism, soil enzyme activity and following crops.


Assuntos
Proteínas de Bactérias/efeitos adversos , Proteínas de Bactérias/genética , Produtos Agrícolas/genética , Ecossistema , Endotoxinas/efeitos adversos , Endotoxinas/genética , Proteínas Hemolisinas/efeitos adversos , Proteínas Hemolisinas/genética , Plantas Geneticamente Modificadas/genética , Microbiologia do Solo , Animais , Toxinas de Bacillus thuringiensis , Oligoquetos/efeitos dos fármacos
18.
J Anim Physiol Anim Nutr (Berl) ; 95(5): 545-55, 2011 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-21091548

RESUMO

This experiment assessed the effect of feeding genetically modified cottonseed (Bt) containing an insect controlling protein (Cry1Ac) on haematology, blood biochemistry and histopathology of lambs. Haemato-biochemicals were estimated at periodic intervals, and histopathology at termination of experiment. Thirty three weaner lambs were fed a composite feed mixture (CFM) ad libitum individually, in three groups for 123 days. The isonitrogenous CFM had roughage (Perl Millet Stover) and concentrate ratio of 350:650. Diet fed to control lambs contained groundnut oil meal as protein source while other two groups received diet containing either whole cottonseed (N-Bt) or Bt-cottonseed (Bt-CS). Daily feed intake and average daily gain were similar among lambs of three groups. Lambs fed N-Bt diet had higher (p < 0.05) serum protein and globulin compared to control and Bt diets, while albumin content was higher (p = 0.018) in Bt diet fed lambs. Serum urea and creatinin content, alkaline phosphatase (ALP) and serum glutamate pyruvic transaminase (SGPT) activities were not different among lamb groups, while urea and creatinin content and ALP activities increased linearly (p < 0.001) with increased feeding period. Blood haemoglobin (Hb), haematocrit (Hc), white blood cells (WBC), mean corpuscular volume (MCV) and mean corpuscular haemoglobin concentration (MCHC) ranged from 11.1% to 11.2%, 31.8% to 32.8%, 7.0 to 8.3 (× 10(3) /µl), 19.1 to 22.5 fl and 33.2% to 35.5%, respectively, were similar among lamb groups. Erythrocyte sedimentation rate (ESR) (p = 0.008) and red blood cell counts (p = 0.006) were higher in Bt diet fed lambs. Control and N-Bt diet fed lambs had mild fatty infiltration in liver and/or micro-calculi in renal cortex, and such lesions were not seen in Bt diet fed lambs. Growth, haemato-biochemical and histopathology did not change by Bt-CS feeding in growing lamb. However, before recommending the use of Bt-CS in routine feed formulations prolonged feeding experiments of Bt-cotton seed require.


Assuntos
Ração Animal/análise , Proteínas de Bactérias/efeitos adversos , Óleo de Sementes de Algodão/química , Dieta/veterinária , Endotoxinas/efeitos adversos , Proteínas Hemolisinas/efeitos adversos , Ovinos , Animais , Toxinas de Bacillus thuringiensis , Análise Química do Sangue/veterinária , Feminino , Masculino , Ovinos/sangue , Ovinos/crescimento & desenvolvimento
19.
Gynecol Obstet Fertil ; 38(12): 747-53, 2010 Dec.
Artigo em Francês | MEDLINE | ID: mdl-21111655

RESUMO

Endometriosis is an oestrogen-dependent inflammatory disease affecting 10 % of reproductive-aged women. Often accompanied by chronic pelvic pain and infertility, endometriosis rigorously interferes with women's quality of life. Although the pathophysiology of endometriosis remains unclear, a growing body of evidence points to the implication of environmental toxicants. Over the last decade, an increase in the incidence of endometriosis has been reported and coincides with the introduction of genetically modified foods in our diet. Even though assessments of genetically modified food risk have not indicated any hazard on human health, xenobiotics-associated genetically modified food, such as pesticides residues and xenoproteins, could be harmful in the long-term. The "low-dose hypothesis", accumulation and biotransformation of pesticides-associated genetically modified food and the multiplied toxicity of pesticides-formulation adjuvants support this hypothesis. This review summarizes toxic effects (in vitro and on animal models) of some xenobiotics-associated genetically modified food, such as glyphosate and Cry1Ab protein, and extrapolates on their potential role in the pathophysiology of endometriosis. Their roles as immune toxicants, pro-oxidants, endocrine disruptors and epigenetic modulators are discussed.


Assuntos
Endometriose/induzido quimicamente , Alimentos Geneticamente Modificados/efeitos adversos , Xenobióticos/efeitos adversos , Animais , Toxinas de Bacillus thuringiensis , Proteínas de Bactérias/efeitos adversos , Dano ao DNA , Disruptores Endócrinos/efeitos adversos , Endotoxinas/efeitos adversos , Epigenômica , Feminino , Proteínas Hemolisinas/efeitos adversos , Humanos , Infertilidade Feminina/induzido quimicamente , Camundongos , Estresse Oxidativo , Resíduos de Praguicidas/efeitos adversos , Espécies Reativas de Oxigênio/efeitos adversos
20.
Environ Entomol ; 39(2): 707-14, 2010 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-20388306

RESUMO

Corn (Zea mays L.) transformed with a gene from the bacterium Bacillus thuringiensis (Bt) comprises 49% of all corn in the United States. The input of senesced corn tissue expressing the Bt gene may impact stream-inhabiting invertebrates that process plant debris, especially trichopteran species related to the target group of lepidopteran pests. Our goal was to assess risk associated with transgenic corn debris entering streams. First, we show the input of corn tissue after harvest was extended over months in a stream. Second, using laboratory bioassays based on European corn borer [Ostrinia nubilalis (Hübner)], we found no bioactivity of Cry1Ab protein in senesced corn tissue after 2 wk of exposure to terrestrial or aquatic environments. Third, we show that Bt near-isolines modify growth and survivorship of some species of invertebrates. Of the four nontarget invertebrate species fed Bt near-isolines, growth of two closely related trichopterans was not negatively affected, whereas a tipulid crane fly exhibited reduced growth rates, and an isopod exhibited reduced growth and survivorship on the Cry1Ab near-isoline but not on the stacked Cry1Ab + Cry3Bb1 near-isoline. Because of lack of evidence of bioactivity of Bt after 2 wk and because of lack of nontarget effects on the stacked near-isoline, we suggest that tissue-mediated differences, and not the presence of the Cry1Ab protein, caused the different responses among the species. Overall, our results provide evidence that adverse effects to aquatic nontarget shredders involve complex interactions arising from plant genetics and environment that cannot be ascribed to the presence of Cry1Ab proteins.


Assuntos
Proteínas de Bactérias/efeitos adversos , Endotoxinas/efeitos adversos , Proteínas Hemolisinas/efeitos adversos , Invertebrados/efeitos dos fármacos , Resíduos de Praguicidas/análise , Poluentes da Água/efeitos adversos , Zea mays/química , Animais , Toxinas de Bacillus thuringiensis , Proteínas de Bactérias/análise , Dípteros , Endotoxinas/análise , Feminino , Proteínas Hemolisinas/análise , Isópodes , Larva , Mariposas , Folhas de Planta/química , Plantas Geneticamente Modificadas/química , Medição de Risco , Poluentes da Água/análise , Zea mays/genética
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