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1.
Psychol Med ; 53(12): 5428-5441, 2023 09.
Artigo em Inglês | MEDLINE | ID: mdl-35879886

RESUMO

BACKGROUND: The impact of the coronavirus disease 2019 (COVID-19) pandemic on mental health is still being unravelled. It is important to identify which individuals are at greatest risk of worsening symptoms. This study aimed to examine changes in depression, anxiety and post-traumatic stress disorder (PTSD) symptoms using prospective and retrospective symptom change assessments, and to find and examine the effect of key risk factors. METHOD: Online questionnaires were administered to 34 465 individuals (aged 16 years or above) in April/May 2020 in the UK, recruited from existing cohorts or via social media. Around one-third (n = 12 718) of included participants had prior diagnoses of depression or anxiety and had completed pre-pandemic mental health assessments (between September 2018 and February 2020), allowing prospective investigation of symptom change. RESULTS: Prospective symptom analyses showed small decreases in depression (PHQ-9: -0.43 points) and anxiety [generalised anxiety disorder scale - 7 items (GAD)-7: -0.33 points] and increases in PTSD (PCL-6: 0.22 points). Conversely, retrospective symptom analyses demonstrated significant large increases (PHQ-9: 2.40; GAD-7 = 1.97), with 55% reported worsening mental health since the beginning of the pandemic on a global change rating. Across both prospective and retrospective measures of symptom change, worsening depression, anxiety and PTSD symptoms were associated with prior mental health diagnoses, female gender, young age and unemployed/student status. CONCLUSIONS: We highlight the effect of prior mental health diagnoses on worsening mental health during the pandemic and confirm previously reported sociodemographic risk factors. Discrepancies between prospective and retrospective measures of changes in mental health may be related to recall bias-related underestimation of prior symptom severity.


Assuntos
COVID-19 , Transtornos de Estresse Pós-Traumáticos , Feminino , Humanos , Transtornos de Estresse Pós-Traumáticos/epidemiologia , Transtornos de Estresse Pós-Traumáticos/psicologia , COVID-19/epidemiologia , Pandemias , Depressão/psicologia , Estudos Retrospectivos , Estudos Prospectivos , SARS-CoV-2 , Ansiedade/psicologia , Reino Unido/epidemiologia
2.
medRxiv ; 2020 Dec 29.
Artigo em Inglês | MEDLINE | ID: mdl-33398302

RESUMO

SARS-CoV-2 Spike protein is critical for virus infection via engagement of ACE2, and amino acid variation in Spike is increasingly appreciated. Given both vaccines and therapeutics are designed around Wuhan-1 Spike, this raises the theoretical possibility of virus escape, particularly in immunocompromised individuals where prolonged viral replication occurs. Here we report chronic SARS-CoV-2 with reduced sensitivity to neutralising antibodies in an immune suppressed individual treated with convalescent plasma, generating whole genome ultradeep sequences by both short and long read technologies over 23 time points spanning 101 days. Although little change was observed in the overall viral population structure following two courses of remdesivir over the first 57 days, N501Y in Spike was transiently detected at day 55 and V157L in RdRp emerged. However, following convalescent plasma we observed large, dynamic virus population shifts, with the emergence of a dominant viral strain bearing D796H in S2 and ΔH69/ΔV70 in the S1 N-terminal domain NTD of the Spike protein. As passively transferred serum antibodies diminished, viruses with the escape genotype diminished in frequency, before returning during a final, unsuccessful course of convalescent plasma. In vitro, the Spike escape double mutant bearing ΔH69/ΔV70 and D796H conferred decreased sensitivity to convalescent plasma, whilst maintaining infectivity similar to wild type. D796H appeared to be the main contributor to decreased susceptibility, but incurred an infectivity defect. The ΔH69/ΔV70 single mutant had two-fold higher infectivity compared to wild type and appeared to compensate for the reduced infectivity of D796H. Consistent with the observed mutations being outside the RBD, monoclonal antibodies targeting the RBD were not impacted by either or both mutations, but a non RBD binding monoclonal antibody was less potent against ΔH69/ΔV70 and the double mutant. These data reveal strong selection on SARS-CoV-2 during convalescent plasma therapy associated with emergence of viral variants with reduced susceptibility to neutralising antibodies.

3.
Cell Death Dis ; 7(6): e2287, 2016 06 30.
Artigo em Inglês | MEDLINE | ID: mdl-27362805

RESUMO

We previously reported that renal clear cell carcinoma cells (RCC) express both tumor necrosis factor receptor (TNFR)-1 and -2, but that, in organ culture, a TNF mutein that only engages TNFR1, but not TNFR2, causes extensive cell death. Some RCC died by apoptosis based on detection of cleaved caspase 3 in a minority TUNEL-positive cells but the mechanism of death in the remaining cells was unexplained. Here, we underpin the mechanism of TNFR1-induced cell death in the majority of TUNEL-positive RCC cells, and show that they die by necroptosis. Malignant cells in high-grade tumors displayed threefold to four fold higher expression of both receptor-interacting protein kinase (RIPK)1 and RIPK3 compared with non-tumor kidney tubular epithelium and low-grade tumors, but expression of both enzymes was induced in lower grade tumors in organ culture in response to TNFR1 stimulation. Furthermore, TNFR1 activation induced significant MLKL(Ser358) and Drp1(Ser616) phosphorylation, physical interactions in RCC between RIPK1-RIPK3 and RIPK3-phospho-MLKL(Ser358), and coincidence of phospho-MLKL(ser358) and phospho-Drp1(Ser616) at mitochondria in TUNEL-positive RCC. A caspase inhibitor only partially reduced the extent of cell death following TNFR1 engagement in RCC cells, whereas three inhibitors, each targeting a different step in the necroptotic pathway, were much more protective. Combined inhibition of caspases and necroptosis provided additive protection, implying that different subsets of cells respond differently to TNF-α, the majority dying by necroptosis. We conclude that most high-grade RCC cells express increased amounts of RIPK1 and RIPK3 and are poised to undergo necroptosis in response to TNFR1 signaling.


Assuntos
Apoptose , Carcinoma de Células Renais/patologia , Células Epiteliais/metabolismo , Neoplasias Renais/patologia , Túbulos Renais/patologia , Proteína Serina-Treonina Quinases de Interação com Receptores/metabolismo , Receptores Tipo I de Fatores de Necrose Tumoral/metabolismo , Acrilamidas/farmacologia , Apoptose/efeitos dos fármacos , Carcinoma de Células Renais/genética , Células Epiteliais/efeitos dos fármacos , Células Epiteliais/patologia , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Humanos , Marcação In Situ das Extremidades Cortadas , Neoplasias Renais/genética , Necrose , Técnicas de Cultura de Órgãos , Quinazolinonas/farmacologia , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Proteína Serina-Treonina Quinases de Interação com Receptores/genética , Transdução de Sinais/efeitos dos fármacos , Sulfonamidas/farmacologia , Fator de Necrose Tumoral alfa/farmacologia , Regulação para Cima/efeitos dos fármacos
4.
J Vasc Res ; 50(4): 324-31, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23860328

RESUMO

We describe a method for coculture of macro- or microvascular human endothelial cells (ECs) and pericytes (PCs) within a 3-dimensional (3-D) protein matrix resulting in lumenized EC cords invested by PCs. To prevent apoptotic cell death of ECs in 3-D culture, human umbilical vein or dermal microvascular ECs were transduced to express the antiapoptotic protein Bcl-2. To prevent PC-mediated gel contraction, the collagen-fibronectin gel was polymerized within a polyglycolic acid nonwoven matrix. Over the first 24-48 h, EC-only gels spontaneously formed cords that developed lumens via vacuolization; such vascular networks were maintained for up to 7 days. In EC-PC cocultures, PCs were recruited to the EC networks. PC investment of EC cords both limited the lumen diameter and increased the degree of vascular network arborization. Peg and socket junctions formed between ECs and PCs in this system, but dye transfer, indicative of gap junction formation, was not observed. This simple system can be used to analyze bidirectional signals between ECs and PCs in a 3-D geometry.


Assuntos
Comunicação Celular , Células Endoteliais/fisiologia , Células Endoteliais da Veia Umbilical Humana/fisiologia , Microvasos/fisiologia , Neovascularização Fisiológica , Pericitos/fisiologia , Apoptose , Movimento Celular , Células Cultivadas , Técnicas de Cocultura , Colágeno/metabolismo , Células Endoteliais/metabolismo , Fibronectinas/metabolismo , Células Endoteliais da Veia Umbilical Humana/metabolismo , Humanos , Junções Intercelulares/fisiologia , Microvasos/metabolismo , Pericitos/metabolismo , Ácido Poliglicólico/química , Polimerização , Proteínas Proto-Oncogênicas c-bcl-2/genética , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Fatores de Tempo , Transdução Genética , Transfecção
5.
Poult Sci ; 92(3): 719-25, 2013 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-23436522

RESUMO

An experiment was conducted to evaluate the influence of a novel microbial phytase on broiler performance from d 0 to 42 and tibia ash at d 21. Male Cobb 500 broilers (n = 2,016) were fed 1 of 7 experimental diets: positive control (PC) formulated to meet or exceed nutrient recommendations; PC plus dicalcium phosphate (PC+DCP) formulated to provide Ca and P at 0.10% above the PC; PC plus 500 U/kg of microbial phytase (PC+500); negative control (NC) with Ca and P reduced from the PC by 0.16 and 0.15%, respectively; and NC plus 500 (NC+500), 1,000 (NC+1,000), or 1,500 (NC+1,500) U/kg of microbial phytase. Diets were fed in 3 phases from d 0 to 21, d 22 to 42, and d 43 to 49 to 32 birds/pen and 9 replicate pens/diet. From d 0 to 21, broilers fed the NC diet had decreased (P ≤ 0.05) BW gain and tibia ash compared with broilers fed all other diets, except tibia ash in birds fed PC+500. Phytase supplementation at 500, 1,000, or 1,500 U/kg to the NC improved (P ≤ 0.05) BW gain and tibia ash comparable with the PC. Feed conversion ratio (FCR) was improved (P ≤ 0.05) in broilers fed NC+1,500 compared with broilers fed all other diets. From d 0 to 49, growth performance was not influenced (P > 0.05) by diet. However, FCR was improved (P ≤ 0.05) in broilers fed 1,500 U/kg of microbial phytase compared with broilers fed the PC, PC+DCP, and NC. There were no differences in performance or tibia ash between broilers fed the PC or PC+DCP, which would indicate the PC diet was sufficient in Ca and P. Therefore, the improvements in FCR in the NC+1500 may be associated with mitigation of the antinutrient effects of phytate rather than improved P utilization.


Assuntos
6-Fitase/administração & dosagem , 6-Fitase/farmacologia , Galinhas/crescimento & desenvolvimento , Fósforo/metabolismo , 6-Fitase/metabolismo , Animais , Relação Dose-Resposta a Droga , Masculino
6.
Med Eng Phys ; 35(4): 457-69, 2013 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-22835436

RESUMO

Multiple-breath-washout (MBW) measurements are regarded as a sensitive technique which can reflect the ventilation inhomogeneity of respiratory airways. Typically nitrogen is used as the tracer gas and is washed out by pure oxygen in multiple-breath-nitrogen washout (MBNW) tests. In this study, instead of using nitrogen, (4)He is used as the tracer gas with smaller gas density which may be able to reach deeper into our lungs in a given time and the helium washout results may be more sensitive to the ventilation inhomogeneity in small airways. A multiple-breath-helium-washout (MBHW) system developed for the lung function study is also presented. Quartz tuning forks with a resonance frequency of 32,768Hz have been used for detecting the change of the respiratory gas density. The resonance frequency of the quartz tuning fork decreases linearly with increasing density of the surrounding gas. Knowing the CO2 concentration from the infrared carbon dioxide detector, the helium concentration can be determined. Results from 14 volunteers (3 mild asthmatics, 4 tobacco smokers, 1 with asthma history, 1 with COPD history, 5 normal) have shown that mild asthmatics have higher ventilation inhomogeneity in either conducting or acinar airways (or both). A feature has been found in washout curve of single breaths from 4 tobacco smokers with different length of smoking history which may indicate the early stage of respiratory ventilation inhomogeneity in acinar airways.


Assuntos
Hélio/metabolismo , Respiração , Testes de Função Respiratória/métodos , Adulto , Hélio/administração & dosagem , Humanos , Masculino , Pessoa de Meia-Idade , Doença Pulmonar Obstrutiva Crônica/fisiopatologia , Fumar/fisiopatologia , Adulto Jovem
7.
J Econ Entomol ; 103(6): 2236-41, 2010 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-21309249

RESUMO

Cotton, Gossypium hirsutum L., bolls from 17 field locations in northeastern North Carolina and southeastern Virginia, having 20% or greater internal boll damage, were studied to determine the relationship between external feeding symptoms and internal damage caused by stink bug (Hemiptera: Pentatomidae) feeding. In 2006 and 2007, two cohorts of 100 bolls each were sampled at all field locations. The first cohort was removed as bolls reached approximately quarter size in diameter (2.4 cm). External and internal symptoms of stink bug feeding were assessed and tabulated. Concurrent to when the first cohort was collected, a second cohort of quarter-size-diameter bolls was identified, tagged, examined in situ for external feeding symptoms (sunken lesions), and harvested at the black seed coat stage. Harvested bolls were assessed for internal damage and locks were categorized (undamaged, minor damage, or major damage), dried, and ginned. Lint samples from each damage category were submitted for high volume instrument and advanced fiber information system quality analyses. Significant, moderately strong Pearson correlation coefficients existed between number of external stink bug feeding lesions and internal damage. Pearson correlation of total external lesions with total internal damage was stronger than any correlation among the other single components compared. Predictability plots indicated a rapid increase in relationship strength when relating external stink bug lesions to internal damage as the number of external lesions increased. Approximately 90% predictability of internal damage was achieved with four (2006) or six (2007) external lesions per boll. Gin-turnout and fiber quality decreased with increasing intensity of internal stink bug damage.


Assuntos
Fibra de Algodão/normas , Gossypium/parasitologia , Heterópteros/fisiologia , Interações Hospedeiro-Parasita , Animais , Comportamento Alimentar
8.
Am J Transplant ; 9(12): 2679-96, 2009 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-19788501

RESUMO

Tumor necrosis factor (TNF) utilizes two receptors, TNFR1 and 2, to initiate target cell responses. We assessed expression of TNF, TNFRs and downstream kinases in cardiac allografts, and compared TNF responses in heart organ cultures from wild-type ((WT)C57BL/6), TNFR1-knockout ((KO)), TNFR2(KO), TNFR1/2(KO) mice. In nonrejecting human heart TNFR1 was strongly expressed coincidentally with inactive apoptosis signal-regulating kinase-1 (ASK1) in cardiomyocytes (CM) and vascular endothelial cells (VEC). TNFR2 was expressed only in VEC. Low levels of TNF localized to microvessels. Rejecting cardiac allografts showed increased TNF in microvessels, diminished TNFR1, activation of ASK1, upregulated TNFR2 co-expressed with activated endothelial/epithelial tyrosine kinase (Etk), increased apoptosis and cell cycle entry in CM. Neither TNFR was expressed significantly by cardiac fibroblasts. In (WT)C57BL/6 myocardium, TNF activated both ASK1 and Etk, and increased both apoptosis and cell cycle entry. TNF-treated TNFR1(KO) myocardium showed little ASK1 activation and apoptosis but increased Etk activation and cell cycle entry, while TNFR2(KO) myocardium showed little Etk activation and cell cycle entry but increased ASK1 activation and apoptosis. These observations demonstrate independent regulation and differential functions of TNFRs in myocardium, consistent with TNFR1-mediated cell death and TNFR2-mediated repair.


Assuntos
MAP Quinase Quinase Quinase 5/metabolismo , Miócitos Cardíacos/metabolismo , Proteínas Tirosina Quinases/metabolismo , Receptores Tipo II do Fator de Necrose Tumoral/metabolismo , Receptores Tipo I de Fatores de Necrose Tumoral/metabolismo , Animais , Apoptose/fisiologia , Ciclo Celular/fisiologia , Morte Celular , Endotélio Vascular/metabolismo , Ativação Enzimática , Rejeição de Enxerto/metabolismo , Transplante de Coração , Humanos , Camundongos , Camundongos Knockout , Miocárdio/metabolismo , Técnicas de Cultura de Órgãos , RNA Mensageiro/metabolismo , Fator de Necrose Tumoral alfa/fisiologia
10.
J Pathol ; 214(2): 149-60, 2008 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-18161752

RESUMO

TNF was originally described as a circulating factor that can cause necrosis of tumours, but has since been identified as a key regulator of the inflammatory response. This review describes the known signalling pathways and cell biological effects of TNF, and our understanding of the role of TNF in human disease. TNF interacts with two different receptors, designated TNFR1 and TNFR2, which are differentially expressed on cells and tissues and initiate both distinct and overlapping signal transduction pathways. These diverse signalling cascades lead to a range of cellular responses, which include cell death, survival, differentiation, proliferation and migration. Vascular endothelial cells respond to TNF by undergoing a number of pro-inflammatory changes, which increase leukocyte adhesion, transendothelial migration and vascular leak and promote thrombosis. The central role of TNF in inflammation has been demonstrated by the ability of agents that block the action of TNF to treat a range of inflammatory conditions, including rheumatoid arthritis, ankylosing spondylitis, inflammatory bowel disease and psoriasis. The increased incidence of infection in patients receiving anti-TNF treatment has highlighted the physiological role of TNF in infectious diseases.


Assuntos
Inflamação/imunologia , Fator de Necrose Tumoral alfa/imunologia , Anti-Inflamatórios não Esteroides/uso terapêutico , Artrite/tratamento farmacológico , Artrite/imunologia , Doenças Transmissíveis/imunologia , Humanos , Inflamação/tratamento farmacológico , Receptores do Fator de Necrose Tumoral/metabolismo , Transdução de Sinais/imunologia , Fator de Necrose Tumoral alfa/antagonistas & inibidores , Fator de Necrose Tumoral alfa/biossíntese
11.
J Econ Entomol ; 101(6): 1950-9, 2008 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-19133479

RESUMO

Cotton, Cossypium hirsutum L, plants expressing Cry1Ac and Cry1F (Phytogen 440W) insecticidal crystal proteins of Bacillus thuringiensis (Bt) Berliner, were evaluated against natural populations of tobacco budworm, Heliothis virescens (F.), and bollworm, Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae), across 13 southern U.S. locations that sustained low, moderate, and high infestations. The intrinsic activity of Phytogen 440W was compared with nontreated non-Bt cotton (PSC355) and with management strategies in which supplemental insecticides targeting heliothines were applied to Phytogen 440W and to PSC355 cotton. Infestations were composed primarily of bollworm, which is the least sensitive of the heliothine complex to Cry toxins. Therefore, damage recorded in these studies was primarily due to bollworm. Greater than 75% of all test sites sustained heliothine infestations categorized as moderate to high (10.6-64.0% peak damaged bolls in nontreated PSC355). Phytogen 440W, alone or managed with supplemental insecticide applications, reduced heliothine-damaged plant terminals, squares (flower buds), flowers, and bolls equal to or better (1.0-79.0-fold) than managing a non-Bt cotton variety with foliar insecticides across all infestation environments. Rarely (frequency of < or = 11% averaged across structures), sprayed Phytogen 440W reduced damaged structures compared with nontreated Phytogen 440W. Protection against heliothine-induced plant damage was similar across the three levels of infestation for each viable management strategy, with exception to damaged squares for nontreated Phytogen 440W. In situations of moderate to high heliothine infestations, cotton plants expressing Cry1Ac and Cry1F may sustain higher levels of damage compared with that same variety in low infestations. No significant difference in yield was observed among heliothine management strategies within each infestation level, indicating cotton plants may compensate for those levels of plant damage. These findings indicate Phytogen 440W containing Cry1Ac and Cry1F provided consistent control of heliothines across a range of environments and infestation levels.


Assuntos
Proteínas de Bactérias/metabolismo , Endotoxinas/metabolismo , Gossypium/genética , Proteínas Hemolisinas/metabolismo , Controle de Insetos/métodos , Mariposas , Plantas Geneticamente Modificadas/metabolismo , Animais , Toxinas de Bacillus thuringiensis , Proteínas de Bactérias/genética , Endotoxinas/genética , Gossypium/crescimento & desenvolvimento , Proteínas Hemolisinas/genética , Inseticidas , Plantas Geneticamente Modificadas/crescimento & desenvolvimento , Estados Unidos
12.
J Insect Sci ; 8: 9, 2008.
Artigo em Inglês | MEDLINE | ID: mdl-20345293

RESUMO

The influence, if any, of 5m wide, feral, herbaceous field borders on pest and beneficial arthropods in commercial cotton, Gossypium hirsutum (L.) (Malvales: Malvaceae), fields was measured through a variety of sampling techniques over three years. In each year, 5 fields with managed, feral vegetation borders and five fields without such borders were examined. Sampling was stratified from the field border or edge in each field in an attempt to elucidate any edge effects that might have occurred. Early season thrips populations appeared to be unaffected by the presence of a border. Pitfall sampling disclosed no differences in ground-dwelling predaceous arthropods but did detect increased populations of crickets around fields with borders. Cotton aphid (Aphis gossypii Glover) (Hemiptera: Aphididae) populations were too low during the study to adequately assess border effects. Heliothines, Heliothis virescens (F.) and Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae), egg numbers and damage rates were largely unaffected by the presence or absence of a border, although in one instance egg numbers were significantly lower in fields with borders. Overall, foliage-dwelling predaceous arthropods were somewhat more abundant in fields with borders than in fields without borders. Tarnished plant bugs, Lygus lineolaris (Palisot de Beauvois) (Heteroptera: Miridae) were significantly more abundant in fields with borders, but stink bugs, Acrosternum hilare (Say), and Euschistus servus (Say) (Hemiptera: Pentatomidae) numbers appeared to be largely unaffected by border treatment. Few taxa clearly exhibited distributional edge effects relative to the presence or absence of border vegetation. Field borders like those examined in this study likely will have little impact on insect pest management in cotton under current insect management regimens.


Assuntos
Agricultura/métodos , Gossypium/parasitologia , Interações Hospedeiro-Parasita/fisiologia , Insetos/fisiologia , Animais , Inseticidas , North Carolina , Densidade Demográfica
13.
J Econ Entomol ; 100(3): 801-7, 2007 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-17598541

RESUMO

Field experiments were conducted from 1972 to 1978 and from 1998 to 1999 to evaluate tobacco budworm, Heliothis virescens (F.) (Lepidoptera: Noctuidae), larval feeding on flue-cured tobacco, Nicotiana tabacum (L.), yield in eastern North Carolina. In the earlier studies, using variety Coker 319, treatment plots were evaluated when either 0 or 100% of plants in a plot were infested with H. virescens larvae. Treatment differences based on actual yield loss (kilograms per hectare) were compared with estimations of yield loss based on leaf consumption and leaf loss. Results indicate actual yield loss when 100% of plants were infested was less than the corresponding estimates of yield loss. In the later experiments, two tobacco budworm-resistant lines, 'CU 263' and 'CU 370', were compared with a commercial susceptible variety, K 326, when 0, 10, 20, or 40% of plants were infested (1998) and 0, 10, 40, 75, or 100% of plants were infested (1999). Although significant increases in leaf equivalents consumed were associated with infestations exceeding the recommended threshold, differences were not detected for yield (kilograms per hectare), quality (dollars per kilogram), and value (dollars per hectare) within each tobacco line. Additionally, there was not a significant correlation between value and infestations level for any of the tobacco lines. These results provide economic support for tolerance of a higher treatment threshold. Although K 326 sustained more leaf equivalent loss than CU 263 and CU 370, the value of K 326 harvested was higher than that of CU 263 and CU 370. To justify use of resistant varieties, the combination of pest pressure and the benefit of host plant resistance must be greater than the capacity of a susceptible variety to produce competitive yields, despite sustaining significantly higher loss.


Assuntos
Mariposas/fisiologia , /parasitologia , Agricultura/economia , Animais , Comportamento Alimentar , Larva/crescimento & desenvolvimento , Larva/fisiologia , Mariposas/crescimento & desenvolvimento , North Carolina , Controle de Pragas/economia , Folhas de Planta/parasitologia , Densidade Demográfica , /classificação
14.
J Econ Entomol ; 100(1): 180-6, 2007 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-17370826

RESUMO

One susceptible and three Cry1Ac-resistant strains of tobacco budworm, Heliothis virescens (F.) (Lepidoptera: Noctuidae), were used in laboratory studies to determine the level of cross-resistance between the Bacillus thuringiensis (Berliner) toxins Cry1Ac and Vip3A by using concentration-mortality and leaf tissue experiments. Concentration-mortality data demonstrated that the three Cry1Ac-resistant H. virescens strains, YHD2, KCBhyb, and CxC, were at least 215- to 316-fold resistant to Cry1Ac compared with the susceptible strain, YDK. Results from Vip3A concentration-mortality tests indicated that mortality was similar among all four H. virescens strains. Relative larval growth on Cry1Ac reflected concentration-mortality test results, because YHD2 larval growth was mostly unaffected by the Cry1Ac concentrations tested. Growth ratios for KCBhyb and CXC indicated that they had a more moderate level of resistance to Cry1Ac than did YHD2. Relative larval growth on Vip3A was highly variable at lower concentrations, but it was more consistent on concentrations of Vip3A above 25 microg/ml. Differences in larval growth among strains on Vip3A were not as pronounced as seen in Cry1Ac experiments. Mortality and larval growth also was assessed in leaf tissue bioassays in which YDK, CxC, and KCBhyb neonates were placed onto leaf disks from non-Bt and Bt cotton, Gossypium hirsutum L., for 5 d. Three Bt lines were used in an initial bioassay and consisted of two Vip3A-containing lines, COT203 and COT102, and a Cry1Ac-producing line. Mortality of KCBhyb and CXC was lower than that of YDK larvae in the presence of leaf tissue from the Cry1Ac-producing line. Additionally, increased larval growth and leaf tissue consumption on Cry1Ac-containing leaf disks was observed for KCBhyb and CXC. Mortality and larval weights were similar among strains when larvae were fed leaf tissue of either non-Bt, COT203, or COT102. A subsequent leaf tissue bioassay was conducted that evaluated four cotton lines: non-Bt, Cry1Ab-expressing, Vip3A-expressing, and pyramided-toxin plants that produced both Cry1Ab and Vip3A. Mortality levels were similar among strains when fed non-Bt, Vip3A-expressing, or pyramided-toxin leaf tissues. Mortality was higher for YDK than for KCBhyb or CXC on Cry1Ab-expressing leaf tissues. No differences in larval weights were observed among strains for any genotype tested. Results of these experiments demonstrate that cross-resistance is nonexistent between CrylAc and Vip3A in H. virescens. Thus, the introduction of Vip3A-producing lines could delay Cry1Ac-resistance evolution in H. virescens, if these lines gain a significant share of the market.


Assuntos
Proteínas de Bactérias/farmacologia , Toxinas Bacterianas/farmacologia , Endotoxinas/farmacologia , Proteínas Hemolisinas/farmacologia , Resistência a Inseticidas/genética , Inseticidas/farmacologia , Mariposas/efeitos dos fármacos , Animais , Toxinas de Bacillus thuringiensis , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Regulação da Expressão Gênica de Plantas , Gossypium/genética , Mariposas/genética , Plantas Geneticamente Modificadas
15.
J Econ Entomol ; 99(5): 1790-7, 2006 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-17066814

RESUMO

To evaluate resistance to Bacillus thuringiensis Berliner (Bt) toxins, adult female bollworms, Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae), were collected from four light trap locations in two eastern North Carolina counties from August to October during 2001 and 2002. Females were allowed to oviposit, and upon hatching, 24 neonates from each female (F1 lines) were screened for survival and growth rate on each of three diets: non-Bt diet, diet containing 5.0 microg/ml Cry1Ac toxin, or diet containing 5.0 microg/ml Cry2Ab toxin. These screens were designed to identify nonrecessive Bt resistance alleles present in field populations of bollworm. Of 561 and 691 families screened with both Cry1Ac- and Cry2Ab-containing diets in 2001 and 2002, respectively, no F1 lines were identified that seemed to carry a gene conferring substantial resistance to either Cry1Ac or Cry2Ab. Adults from F1 lines with growth scores in the highest (R) and lowest (S) quartiles were mated in four combinations, RxR, SxR, RxS, and SxS. Differences in growth rates of larvae from these crosses demonstrated that there is substantial quantitative genetic variation in eastern North Carolina populations for resistance to both Cry1Ac and Cry2Ab toxins. These findings, in addition to results suggesting partially dominant inheritance of resistance to Cry1Ac and Cry2Ab, are critically important for determining appropriate resistance management strategies that impact the sustainability of transgenic cotton, Gossypium hirsutum (L.).


Assuntos
Proteínas de Bactérias , Toxinas Bacterianas , Endotoxinas , Proteínas Hemolisinas , Mariposas/genética , Animais , Toxinas de Bacillus thuringiensis , Feminino , Variação Genética , Gossypium/parasitologia , Resistência a Inseticidas/genética , Larva/crescimento & desenvolvimento , Mariposas/crescimento & desenvolvimento , North Carolina
16.
J Magn Reson ; 175(2): 210-21, 2005 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-15908247

RESUMO

Concerted double proton transfer in the hydrogen bonds of a carboxylic acid dimer has been studied using 13C field-cycling NMR relaxometry. Heteronuclear 13C-1H dipolar interactions dominate the 13C spin-lattice relaxation which is significantly influenced by the polarisation state of the 1H Zeeman reservoir. The methodology of field-cycling experiments for such heteronuclear spin-coupled systems is studied experimentally and theoretically, including an investigation of various saturation-recovery and polarisation-recovery pulse sequence schemes. A theoretical model of the spin-lattice relaxation of this coupled system is presented which is corroborated by experiment. Spectral density components with frequencies omega(C), omega(C) + omega(H), and omega(C) - omega(H) are mapped out experimentally from the magnetic field dependence of the 13C and 1H spin-lattice relaxation and the proton transfer rate at low temperature is determined from their widths. Any dynamic isotope effect on the proton tunnelling in the hydrogen bond arising from 13C enrichment in the skeletal framework of the dimer is found to be smaller than experimental uncertainties (approximately 5%).


Assuntos
Ácido Benzoico/química , Ressonância Magnética Nuclear Biomolecular/métodos , Isótopos de Carbono , Ligação de Hidrogênio , Modelos Químicos , Modelos Moleculares , Estrutura Molecular , Prótons
17.
J Econ Entomol ; 97(5): 1719-25, 2004 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-15568364

RESUMO

Transgenic cotton, Gossypium hirsutum (L.), expressing either one or two Bacillus thuringiensis ssp. kurstaki Berliner (Bt) proteins was compared with the conventional sister line in field experiments with regard to production of bollworm, Helicoverpa zea (Boddie), and bolls damaged by bollworm. The relative numbers of bollworms that developed on Bollgard (Monsanto Co., St. Louis, MO), Bollgard II (Monsanto Co.), and conventional cotton were estimated under nontreated conditions in 2000 and both insecticide-treated and nontreated conditions in 2001-2002 in North Carolina tests. Averaged across seven field studies under nontreated conditions, Bollgard cotton generated statistically similar numbers of large (L4-L5) bollworm larvae compared with the conventional variety; however, Bollgard cotton produced significantly fewer damaged bolls and bollworm adults than the conventional variety. Production of large larvae, damaged bolls, and adults was decreased dramatically by Bollgard II cotton as compared with Bollgard and conventional varieties. When comparing insecticide-treated and nontreated cotton genotypes, both Bt cotton sustained less boll damage than the conventional variety averaged across insecticide regimes; furthermore, Bollgard II cotton had fewer damaged bolls than the Bollgard variety. When averaged across cotton genotypes, pyrethroid oversprays reduced the numbers of damaged bolls compared with the nontreated cotton. Insecticide-treated Bollgard cotton, along with insecticide-treated and nontreated Bollgard II cotton reduced production of bollworm larvae, pupae, and adults. However, the addition of pyrethroid oversprays to Bollgard II cotton seemed to be the best resistance management strategy available for bollworm because no bollworms were capable of completing development under these conditions.


Assuntos
Bacillus thuringiensis , Proteínas de Bactérias/biossíntese , Toxinas Bacterianas/biossíntese , Endotoxinas/biossíntese , Gossypium/genética , Inseticidas , Lepidópteros , Controle Biológico de Vetores/métodos , Animais , Toxinas de Bacillus thuringiensis , Gossypium/parasitologia , Proteínas Hemolisinas , Resistência a Inseticidas , Plantas Geneticamente Modificadas , Dinâmica Populacional
18.
J Econ Entomol ; 96(1): 137-42, 2003 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-12650356

RESUMO

In summer 2000, adult female bollworm moths, Helicoverpa zea (Boddie), were collected from light-traps at four locations near the Tidewater Research Station, Plymouth, NC. Female moths were allowed to lay eggs, and at hatch, 72 larvae from each female were screened for growth rate on normal artificial diet and on diets containing 5.0 microg of either Cry1Ac or Cry2Aa Bt toxin per milliliter of diet. The growth rate bioassays were performed to isolate nonrecessive Bt resistance genes present in field populations of bollworm. We found one individual out of 583 screened that appeared to carry a major gene for resistance to Cry1Ac. Assuming four alleles per individual, the gene frequency is 1/2332 or 0.0003. Other females appeared to have minor genes for Cry1Ac resistance or major genes with lower levels of dominance. We also found one individual out of 646 screened that appeared to carry a major gene for resistance to Cry2Aa. The gene frequency for Cry2Aa resistance was estimated at 1/2584 or 0.00039. Again, other females seemed to carry additional minor resistance genes. Along with other results that indicate partially dominant inheritance of Cry1Ac resistance in bollworm, these allele frequency estimates are important for determining the rate of resistance evolution in H. zea to specific Bt toxins.


Assuntos
Bacillus thuringiensis , Proteínas de Bactérias , Toxinas Bacterianas , Endotoxinas , Resistência a Inseticidas/genética , Inseticidas , Mariposas/genética , Animais , Toxinas de Bacillus thuringiensis , Feminino , Frequência do Gene , Proteínas Hemolisinas , Mariposas/crescimento & desenvolvimento , North Carolina
19.
Lab Invest ; 81(11): 1503-15, 2001 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-11706058

RESUMO

Activation of the TNF signal transduction cascade is initiated by the interaction of TNF with either of two cell surface receptors, TNFR-1 and TNFR-2. The levels and regulation of expression of these two receptors has been extensively analyzed in cultured cells, but little is known of TNFR expression in situ. We analyzed the expression of TNFR-1 and -2 in normal human renal kidney and in renal transplants undergoing acute cellular rejection. Immunohistochemistry and immunogold electron microscopy indicated a strong expression of TNFR-1 on the endothelium of glomeruli of normal kidney. Immunogold colocalization for TNFR-1 and a marker of the trans-Golgi network (TGN-46) demonstrated TNFR-1 within the Golgi complex in endothelial cells in normal kidney, confirming our previous studies with cultured cells. TNFR-1 expression was lost in glomeruli from acutely rejecting kidney, but TNFR-1 was detected in abundance on infiltrating leukocytes in the interstitium of allografts with acute rejection. In contrast, TNFR-2 was demonstrated predominantly in epithelial cells of distal convoluted tubule (DCT) in acute rejection kidney near TNF-expressing leukocytes. TNF was absent in normal kidney, but present in rejecting allograft. TNF was found in infiltrating leukocytes and in adjacent tubular epithelial cells. In situ hybridization showed TNFR-1 mRNA within the endothelium of the glomeruli and of a few arterioles in normal kidney, whereas TNFR-2 mRNA was seen in tubular epithelial cells of the DCT in acute transplant rejection. These data reveal that there is both differential expression and regulation of the two TNF receptors in human kidney.


Assuntos
Antígenos CD/genética , Rejeição de Enxerto/fisiopatologia , Transplante de Rim , Rim/fisiologia , Receptores do Fator de Necrose Tumoral/genética , Doença Aguda , Antígenos CD/análise , Corantes , Amarelo de Eosina-(YS) , Corantes Fluorescentes , Expressão Gênica , Rejeição de Enxerto/patologia , Hematoxilina , Humanos , Rim/química , Rim/ultraestrutura , Falência Renal Crônica/patologia , Falência Renal Crônica/fisiopatologia , Falência Renal Crônica/cirurgia , Microscopia Imunoeletrônica , Receptores do Fator de Necrose Tumoral/análise , Receptores Tipo I de Fatores de Necrose Tumoral , Receptores Tipo II do Fator de Necrose Tumoral , Fator de Necrose Tumoral alfa/análise
20.
Oncogene ; 20(44): 6482-91, 2001 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-11607847

RESUMO

Tumor necrosis factor receptor-associated factors (TRAFS) were initially discovered as adaptor proteins that couple the tumor necrosis factor receptor family to signaling pathways. More recently they have also been shown to be signal transducers of Toll/interleukin-1 family members. Six members of the TRAF family have been identified. All TRAF proteins share a C-terminal homology region termed the TRAF domain that is capable of binding to the cytoplasmic domain of receptors, and to other TRAF proteins. In addition, TRAFs 2-6 have RING and zinc finger motifs that are important for signaling downstream events. TRAF proteins are thought to be important regulators of cell death and cellular responses to stress, and TRAF2, TRAF5 and TRAF6 have been demonstrated to mediate activation of NF-kappaB and JNK. TRAF proteins are expressed in normal and diseased tissue in a regulated fashion, suggesting that they play an important role in physiological and pathological processes.


Assuntos
Receptores do Fator de Necrose Tumoral/química , Receptores do Fator de Necrose Tumoral/metabolismo , Receptores do Fator de Necrose Tumoral/fisiologia , Transdução de Sinais , Motivos de Aminoácidos , Animais , Humanos , Interleucina-1/metabolismo , Ligação Proteica , Estrutura Terciária de Proteína , Proteínas/metabolismo , Fator 1 Associado a Receptor de TNF , Fator 2 Associado a Receptor de TNF , Fator 3 Associado a Receptor de TNF , Fator 4 Associado a Receptor de TNF , Fator 5 Associado a Receptor de TNF , Fator 6 Associado a Receptor de TNF , Fator de Transcrição AP-1/metabolismo , Peptídeos e Proteínas Associados a Receptores de Fatores de Necrose Tumoral
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