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1.
J Econ Entomol ; 2024 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-38748467

RESUMO

Biopesticides based on RNA interference (RNAi) took a major step forward with the first registration of a sprayable RNAi product, which targets the world's most damaging potato pest. Proactive resistance management is needed to delay the evolution of resistance by pests and sustain the efficacy of RNAi biopesticides.

3.
Pestic Biochem Physiol ; 199: 105777, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38458684

RESUMO

The fall armyworm (Spodoptera frugiperda) is a major global pest causing severe damage to various crops, especially corn. Transgenic corn producing the Cry1F pesticidal protein from the bacterium Bacillus thuringiensis (Cry1F corn) showed effectiveness in controlling this pest until S. frugiperda populations at locations in North and South America evolved practical resistance. The mechanism for practical resistance involved disruptive mutations in an ATP binding cassette transporter subfamily C2 gene (SfABCC2), which serves as a functional Cry1F receptor in the midgut cells of susceptible S. frugiperda. The SfABCC2 protein contains two transmembrane domains (TMD1 and TMD2), each with a cytosolic nucleotide (ATP) binding domain (NBD1 and NBD2, respectively). Previous reports have demonstrated that disruptive mutations in TMD2 were linked with resistance to Cry1F, yet whether the complete SfABCC2 structure is needed for receptor functionality or if a single TMD-NBD protein can serve as functional Cry1F receptor remains unknown. In the present study, we separately expressed TMD1 and TMD2 with their corresponding NBDs in cultured insect cells and tested their Cry1F receptor functionality. Our results show that the complete SfABCC2 structure is required for Cry1F receptor functionality. Moreover, binding competition assays revealed that Cry1F specifically bound to SfABCC2, whereas neither SfTMD1-NBD1 nor SfTMD2-NBD2 exhibited any significant binding. These results provide insights into the molecular mechanism of Cry1F recognition by SfABCC2 in S. frugiperda, which could facilitate the development of more effective insecticidal proteins.


Assuntos
Bacillus thuringiensis , Endotoxinas , Animais , Spodoptera , Endotoxinas/genética , Resistência a Inseticidas/genética , Toxinas de Bacillus thuringiensis/metabolismo , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Bacillus thuringiensis/metabolismo , Zea mays , Proteínas Hemolisinas/genética , Plantas Geneticamente Modificadas/genética
4.
Pest Manag Sci ; 80(6): 2796-2803, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38327120

RESUMO

BACKGROUND: Practical resistance of Helicoverpa zea to Cry proteins has become widespread in the US, making Vip3Aa the only effective Bacillus thuringiensis (Bt) protein for controlling this pest. Understanding the genetic basis of Vip3Aa resistance in H. zea is essential in sustaining the long-term efficacy of Vip3Aa. The objectives of this study were to characterize the inheritance of Vip3Aa resistance in four distinct field-derived H. zea strains (M1-RR, AC4-RR, R2-RR and R15-RR), and to test for shared genetic basis among these strains and a previously characterized Texas resistant strain (LT#70-RR). RESULTS: Maternal effects and sex linkage were absent, and the effective dominance level (DML) was 0.0 across Vip3Aa39 concentrations ranging from 1.0 to 31.6 µg cm-2, in all H. zea resistant strains. Mendelian monogenic model tests indicated that Vip3Aa resistance in each of the four strains was controlled by a single gene. However, interstrain complementation tests indicated that three distinct genetic loci are involved in Vip3Aa resistance in the five resistant H. zea strains: one shared by M1-RR and LT#70-RR; another shared by R2-RR and R15-RR; and a distinct one for AC4-RR. CONCLUSION: Results of this study indicate that Vip3Aa resistance in all H. zea strains was controlled by a single, recessive and autosomal gene. However, there were three distinct genetic loci associated with Vip3Aa resistance in the five resistant H. zea strains. The information generated from this study is valuable for exploring mechanisms of Vip3Aa resistance, monitoring the evolution of Vip3Aa resistance, and devising effective strategies for managing Vip3Aa resistance in H. zea. © 2024 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.


Assuntos
Proteínas de Bactérias , Resistência a Medicamentos , Mariposas , Mariposas/efeitos dos fármacos , Mariposas/genética , Bacillus thuringiensis/genética , Proteínas de Bactérias/genética , Proteínas de Bactérias/farmacologia , Resistência a Medicamentos/genética , Controle de Pragas/métodos , Dose Letal Mediana , Teste de Complementação Genética , Genes Recessivos/genética , Animais
5.
Int J Biol Macromol ; 257(Pt 1): 128654, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38065453

RESUMO

The bacterium Bacillus thuringiensis (Bt) is the most economically successful biopesticide to date, and Bt insecticidal proteins are produced in transgenic crops for pest control. However, relevant details in the Bt-mediated killing process remain undefined. In our previous research, we observed reduced larval susceptibility to Bt Cry1Ca in Chilo suppressalis, a major rice pest in China, after gut microbiota elimination. Here, we tested the hypothesis that gut microbiota, particularly abundant Enterococcus spp., influences C. suppressalis susceptibility to Cry1Ca. We isolated and identified four Enterococcus spp. from C. suppressalis gut microbiota and evaluated their impact on Cry1Ca toxicity. Among the four Enterococcus spp. identified, three of them (E. casseliflavus, E. faecalis, and E. mundtii) dramatically increased larval mortality when introduced in axenic C. suppressalis challenged with Cry1Ca. Gut epithelial damage by Cry1Ca promoted the translocation of Enterococcus spp. from the gut lumen into the hemocoel, where they proliferated and induced larval melanization and hemocyte apoptosis. Our combined findings demonstrate that the presence of specific gut microbiota can greatly affect susceptibility to Cry1Ca through melanization and apoptosis of hemocytes. Better understanding of the Bt intoxication process guides the development of bio-enhancers for Bt-based microbial biopesticides and potential improvement of transgenic crops.


Assuntos
Bacillus thuringiensis , Inseticidas , Mariposas , Oryza , Animais , Enterococcus , Endotoxinas/metabolismo , Toxinas de Bacillus thuringiensis/metabolismo , Controle Biológico de Vetores , Plantas Geneticamente Modificadas , Proteínas Hemolisinas/metabolismo , Mariposas/genética , Larva , Inseticidas/farmacologia , Proteínas de Bactérias/toxicidade , Proteínas de Bactérias/metabolismo , Animais Geneticamente Modificados , Oryza/genética
6.
Pest Manag Sci ; 80(2): 905-909, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-37822012

RESUMO

BACKGROUND: Implementation of resistance management tools is crucial for the continued efficacy of insect control technologies. An important aspect of insect resistance management (IRM) is the combined or sequential use of different modes-of-action to reduce selection pressure and delay evolution of resistance. This is especially important for insect pests with established ability to develop resistance to insecticides, such as the Colorado potato beetle (Leptinotarsa decemlineata, CPB). A new class of insecticides, based on double-stranded RNA (dsRNA) activating the gene silencing RNA-interference (RNAi) pathway, are currently under review for regulatory approval and commercial use in the USA against CPB. However, there is no information available on the potential for cross-resistance between RNAi insecticides and other classes of insecticides used against CPB. Herein, we aim to fill this knowledge gap by capitalizing on the availability of a CPB strain highly resistant to dsRNAs and test its susceptibility to diverse small-molecule insecticide classes compared to reference dsRNA-susceptible CPB strains. RESULTS: Differences in activity were observed among the four insecticides tested, with abamectin demonstrating highest activity against all three strains of CPB. However, no differences were observed among the dsRNA-resistant and susceptible CPB strains for any of the tested compounds. Overall, these results demonstrate lack of cross-resistance to commonly used chemical insecticides in the dsRNA-resistant strain of CPB. CONCLUSION: These data support the use of these different insecticide classes along with RNAi-based insecticides as part of an effective insect resistance management framework aimed at delaying resistance in CPB. © 2023 Society of Chemical Industry.


Assuntos
Besouros , Inseticidas , Praguicidas , Solanum tuberosum , Animais , Besouros/genética , Larva , Inseticidas/farmacologia , RNA de Cadeia Dupla/genética , RNA de Cadeia Dupla/farmacologia , Praguicidas/farmacologia , Solanum tuberosum/genética , Interferência de RNA
7.
Nurs Ethics ; 31(1): 65-78, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38111341

RESUMO

The assessment of learning in the ethical domain is one of the most complex aspects to attend in the educational context. In recent years, character education has contributed greatly to different social disciplines, such as education or nursing. However, the development of this approach has run up against several obstacles and limitations, as there is little evidence regarding its long-term effectiveness or its evaluation. This essay aims to identify some of the main difficulties to assess learning in the ethical domain, as obstacles and possible constraints to Aristotelian-based character education. Methodology is analytical and of a philosophical-educational nature, based on which an argumentative analysis is constructed from the bibliographical review of the contributions of classical and contemporary authors. Results show the existence of four major problems and ten associated subproblems, both of an external nature linked to the contextual factors of assessment, and of an internal nature that affect the essence of the process itself, which highlight the difficulty of carrying out assessments of an ethical kind. Far from proposing a pessimistic position, we argue a realistic vision that allows educators at different educational levels to be aware of the limits and critical points of evaluation in the ethical domain.


Assuntos
Aprendizagem , Humanos , Escolaridade
8.
Appl Environ Microbiol ; 89(12): e0164423, 2023 12 21.
Artigo em Inglês | MEDLINE | ID: mdl-38014960

RESUMO

IMPORTANCE: Helicoverpa zea is a major crop pest in the United States that is managed with transgenic corn and cotton that produce insecticidal proteins from the bacterium, Bacillus thuringiensis (Bt). However, H. zea has evolved widespread resistance to the Cry proteins produced in Bt corn and cotton, leaving Vip3Aa as the only plant-incorporated protectant in Bt crops that consistently provides excellent control of H. zea. The benefits provided by Bt crops will be substantially reduced if widespread Vip3Aa resistance develops in H. zea field populations. Therefore, it is important to identify resistance alleles and mechanisms that contribute to Vip3Aa resistance to ensure that informed resistance management strategies are implemented. This study is the first report of reduced binding of Vip3Aa to midgut receptors associated with resistance.


Assuntos
Bacillus thuringiensis , Mariposas , Animais , Estados Unidos , Zea mays/metabolismo , Endotoxinas/metabolismo , Resistência a Inseticidas/genética , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Plantas Geneticamente Modificadas/metabolismo , Proteínas Hemolisinas/genética , Mariposas/genética , Bacillus thuringiensis/genética , Larva/metabolismo
9.
PLoS One ; 18(10): e0292992, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37851680

RESUMO

The genus Diatraea (Lepidoptera: Crambidae) includes stem borers representing the most critical sugarcane pests in the Americas. Colombia's most widely distributed and damaging Diatraea species include Diatraea saccharalis, D. indigenella, D. busckella, and D. tabernella. The reduced efficacy of biological tools commonly used in controlling several species highlights the importance of evaluating alternative management strategies, such as transgenic plants expressing insecticidal proteins from the bacterium Bacillus thuringiensis (Bt). The selection of optimal Bt insecticidal proteins for Diatraea control depends on bioassays with purified Bt proteins. Because there is no described artificial diet for borer species other than D. saccharalis and availability of most purified Bt toxins is restricted, this study aimed at developing a bioassay method using fresh corn tissue and providing proof of concept by testing susceptibility to the Cry1Ac insecticidal protein from Bt. Toxicity was evaluated with a single Cry1Ac dose applied directly to corn discs. Stem borer mortality after seven days was higher than 90% for all four tested Diatraea species, while control mortality was below 8%. In addition, we observed that Cry1Ac caused more than 90% weight inhibition in all survivors and delayed development. These results validate the use of this method to determine mortality and growth inhibition due to the consumption of the Cry1Ac protein in each of the Diatraea species. Furthermore, this method could be used to assess other entomopathogenic substances to control these insect pests.


Assuntos
Bacillus thuringiensis , Inseticidas , Mariposas , Saccharum , Animais , Inseticidas/farmacologia , Endotoxinas/farmacologia , Proteínas de Bactérias/genética , Proteínas de Bactérias/farmacologia , Proteínas Hemolisinas/genética , Mariposas/genética , Bacillus thuringiensis/genética , Zea mays/genética , Plantas Geneticamente Modificadas/genética , Bioensaio , Larva
10.
Toxins (Basel) ; 15(7)2023 07 22.
Artigo em Inglês | MEDLINE | ID: mdl-37505743

RESUMO

The wide occurrence of resistance to Cry1A and Cry2A insecticidal toxins from Bacillus thuringiensis (Bt) in the corn earworm/bollworm Helicoverpa zea (Boddie) leaves the Vip3A toxin produced during the vegetative stage of Bt as the only fully active toxin expressed in transgenic crops to control H. zea in the U.S.A. During 2021, the first unexpected survival of H. zea and injury (UXI) on a maize hybrid expressing Cry1A.105, Cry2Ab2, and Vip3Aa in Louisiana, U.S.A. were observed in two sentinel plots used for resistance monitoring. A follow-up intensive investigation was conducted with two H. zea populations established from larvae collected from the two UXI plots. The main goal of this study was to reveal if the unexpected damage was due to resistance development in the insect to the Bt toxins expressed in the maize hybrid. Diet-overlay bioassays showed that the two populations were highly resistant to Cry1A.105, moderately resistant to Cry2Ab2, but still highly susceptible to Vip3Aa when compared to a reference susceptible strain. In 10 d assays with detached ears, the larvae of the two UXI populations exhibited survival on ears expressing only Cry toxins but presented near 100% mortality on maize hybrids containing both cry and vip3A transgenes. Multiple field trials over three years demonstrated that natural H. zea populations in Louisiana were highly resistant to maize expressing only Cry toxins but remained susceptible to all tested hybrids containing cry and vip3A genes. Altogether, the results of this study suggest that the observed UXIs in Louisiana were associated with a resistance to Cry toxins but were not due to a resistance to Vip3A. The possible causes of the UXIs are discussed. The results generated and procedures adopted in this study help in determining thresholds for defining UXIs, assessing resistance risks, and documenting field resistance.


Assuntos
Bacillus thuringiensis , Mariposas , Animais , Zea mays/genética , Plantas Geneticamente Modificadas/genética , Proteínas de Bactérias/farmacologia , Proteínas de Bactérias/toxicidade , Mariposas/genética , Endotoxinas/genética , Larva , Animais Geneticamente Modificados , Bacillus thuringiensis/genética , Proteínas Hemolisinas/genética , Proteínas Hemolisinas/farmacologia , Resistência a Inseticidas/genética
11.
J Econ Entomol ; 116(3): 935-944, 2023 06 13.
Artigo em Inglês | MEDLINE | ID: mdl-37311017

RESUMO

The fall armyworm, Spodoptera frugiperda (J. E. Smith), is a highly polyphagous pest native to the tropical Americas that has recently spread to become a global super-pest threatening food and fiber production. Transgenic crops producing insecticidal Cry and Vip3Aa proteins from Bacillus thuringiensis (Bt) are used for control of this pest in its native range. The evolution of practical resistance represents the greatest threat to sustainability of this technology and its potential efficacy in the S. frugiperda invasive range. Monitoring for resistance is vital to management approaches delaying S. frugiperda resistance to Bt crops. DNA-based resistance screening provides higher sensitivity and cost-effectiveness than currently used bioassay-based monitoring. So far, practical S. frugiperda resistance to Bt corn-producing Cry1F has been genetically linked to mutations in the SfABCC2 gene, providing a model to develop and test monitoring tools. In this study, we performed targeted SfABCC2 sequencing followed by Sanger sequencing to confirm the detection of known and candidate resistance alleles to Cry1F corn in field-collected S. frugiperda from continental USA, Puerto Rico, Africa (Ghana, Togo, and South Africa), and Southeast Asia (Myanmar). Results confirm that the distribution of a previously characterized resistance allele (SfABCC2mut) is limited to Puerto Rico and identify 2 new candidate SfABCC2 alleles for resistance to Cry1F, one of them potentially spreading along the S. frugiperda migratory route in North America. No candidate resistance alleles were found in samples from the invasive S. frugiperda range. These results provide support for the potential use of targeted sequencing in Bt resistance monitoring programs.


Assuntos
Bacillus thuringiensis , Heterópteros , Animais , Spodoptera/genética , Alelos , Produtos Agrícolas
12.
Front Plant Sci ; 14: 1129454, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36875574

RESUMO

Trypsin inhibitors (TIs) are widely distributed in plants and are known to play a protective role against herbivores. TIs reduce the biological activity of trypsin, an enzyme involved in the breakdown of many different proteins, by inhibiting the activation and catalytic reactions of proteins. Soybean (Glycine max) contains two major TI classes: Kunitz trypsin inhibitor (KTI) and Bowman-Birk inhibitor (BBI). Both genes encoding TI inactivate trypsin and chymotrypsin enzymes, which are the main digestive enzymes in the gut fluids of Lepidopteran larvae feeding on soybean. In this study, the possible role of soybean TIs in plant defense against insects and nematodes was investigated. A total of six TIs were tested, including three known soybean trypsin inhibitors (KTI1, KTI2 and KTI3) and three genes encoding novel inhibitors identified in soybean (KTI5, KTI7, and BBI5). Their functional role was further examined by overexpression of the individual TI genes in soybean and Arabidopsis. The endogenous expression patterns of these TI genes varied among soybean tissues, including leaf, stem, seed, and root. In vitro enzyme inhibitory assays showed significant increase in trypsin and chymotrypsin inhibitory activities in both transgenic soybean and Arabidopsis. Detached leaf-punch feeding bioassays detected significant reduction in corn earworm (Helicoverpa zea) larval weight when larvae fed on transgenic soybean and Arabidopsis lines, with the greatest reduction observed in KTI7 and BBI5 overexpressing lines. Whole soybean plant greenhouse feeding bioassays with H. zea on KTI7 and BBI5 overexpressing lines resulted in significantly reduced leaf defoliation compared to non-transgenic plants. However, bioassays of KTI7 and BBI5 overexpressing lines with soybean cyst nematode (SCN, Heterodera glycines) showed no differences in SCN female index between transgenic and non-transgenic control plants. There were no significant differences in growth and productivity between transgenic and non-transgenic plants grown in the absence of herbivores to full maturity under greenhouse conditions. The present study provides further insight into the potential applications of TI genes for insect resistance improvement in plants.

13.
Insects ; 15(1)2023 Dec 22.
Artigo em Inglês | MEDLINE | ID: mdl-38249013

RESUMO

The fall armyworm (JE Smith) (Spodoptera frugiperda) is a polyphagous pest targeted by selected Cry and Vip3A insecticidal proteins from the bacterium Bacillus thuringiensis (Bt) that are produced in transgenic Bt corn and cotton. Available evidence suggests that sublethal larval exposure to Cry1Ac increases flight activity in adult Spodoptera spp. However, it is not known whether this effect is also observed in survivors from generally lethal exposure to Cry1Ac. Moreover, while multiple cases of field-evolved resistance to Bt proteins have been described in the native range of S. frugiperda, the effect of resistance on flight behavior has not been examined. Long-distance migratory flight capacity of S. frugiperda is of concern given its ongoing global spread and the possibility that migrants may be carrying resistance alleles against pesticides and Bt crops. In this study, we used rotational flight mills to test the effects of generally lethal exposure to Cry1Ac in susceptible and sublethal exposure in Cry1F-resistant S. frugiperda strains. The results detected altered pupal weight after larval feeding on diet containing Cry proteins, which only translated in significantly increased tendency for longer flights in female moths from the susceptible strain. This information has relevant implications when considering current models and assumptions for resistance management of Bt crops.

14.
Front Immunol ; 13: 1022445, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36466886

RESUMO

Midgut receptors have been recognized as the major mechanism of resistance to Cry proteins in lepidopteran larvae, while there is a dearth of data on the role of hemocyte's response to Cry intoxication and resistance development. We aimed at investigating the role of circulating hemocytes in the intoxication of Cry1F toxin in larvae from susceptible (ACB-BtS) and resistant (ACB-FR) strains of the Asian corn borer (ACB), Ostrinia furnacalis. Transcriptome and proteome profiling identified genes and proteins involved in immune-related (tetraspanin and C-type lectins) and detoxification pathways as significantly up-regulated in the hemocytes of Cry1F treated ACB-FR. High-throughput in vitro assays revealed the binding affinity of Cry1F with the tetraspanin and C-type lectin family proteins. We found significant activation of MAPKinase (ERK 1/2, p38α, and JNK 1/2) in the hemocytes of Cry1F treated ACB-FR. In testing plausible crosstalk between a tetraspanin (CD63) and downstream MAPK signaling, we knocked down CD63 expression by RNAi and detected an alteration in JNK 1/2 level but a significant increase in susceptibility of ACB-FR larvae to Cry1F toxin. Information from this study advances a change in knowledge on the cellular immune response to Cry intoxication and its potential role in resistance in a lepidopteran pest.


Assuntos
Bacillus thuringiensis , Animais , Humanos , Larva , Hemócitos , Zea mays , Povo Asiático , Lectinas Tipo C
15.
Sci Rep ; 12(1): 13580, 2022 08 09.
Artigo em Inglês | MEDLINE | ID: mdl-35945334

RESUMO

The fall armyworm (Spodoptera frugiperda) is a highly polyphagous lepidopteran pest of relevant food and fiber staple crops. In the Americas, transgenic corn and cotton producing insecticidal proteins from the bacterium Bacillus thuringiensis (Bt) have controlled and reduced the damage caused by S. frugiperda. However, cases of field-evolved S. frugiperda resistance to Bt corn producing the Cry1F insecticidal protein have been documented in North and South America. When characterized, field resistance to Cry1F is linked to insertions and mutations resulting in a modified or truncated ABC transporter subfamily C2 (SfABCC2) protein that serves as Cry1F receptor in susceptible S. frugiperda. In this work, we present detection of a large genomic deletion (~ 8 kb) affecting the SfABCC2 and an ABC transporter gene subfamily 3 -like gene (SfABCC3) as linked to resistance to Cry1F corn in a S. frugiperda strain from Florida (FL39). Monitoring for this genomic deletion using a discriminatory PCR reaction in field-collected S. frugiperda moths detected individuals carrying this allele in Florida, but not in surrounding states. This is the first report of a large genomic deletion being involved in resistance to a Bt insecticidal protein.


Assuntos
Bacillus thuringiensis , Inseticidas , Transportadores de Cassetes de Ligação de ATP/genética , Animais , Bacillus thuringiensis/genética , Toxinas de Bacillus thuringiensis , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Endotoxinas/genética , Florida , Genômica , Proteínas Hemolisinas/genética , Proteínas Hemolisinas/metabolismo , Proteínas Hemolisinas/farmacologia , Resistência a Inseticidas/genética , Inseticidas/farmacologia , Plantas Geneticamente Modificadas/genética , Spodoptera/metabolismo , Zea mays/genética , Zea mays/metabolismo
16.
Antioxidants (Basel) ; 11(7)2022 Jun 25.
Artigo em Inglês | MEDLINE | ID: mdl-35883739

RESUMO

Microalgae grow in diverse environments and possess a great biotechnological potential as they contain useful bioactive compounds. These bioactive compounds can be obtained by selective and energy-efficient extraction methods. Various industries are using the supercritical fluid extraction (SFE) method to extract these valuable bioactive compounds. Hence, for the first time, we evaluated the effects of SFE on the recovery of bioactive and antioxidant compounds using Coccomyxa onubensis, a eukaryotic acidophilic microalga of potential relevance which can be used in the field of nutraceutical and functional foods. It was isolated from the Tinto River (Pyritic Belt, Huelva, Spain), a mining region in Spain. Variables such as extraction yield, lutein purity (LP) and recovery (LR), total phenols, and antioxidant capacity (Trolox equivalents antioxidant capacity method) were studied using a Box-Behnken design based on a response surface methodology along with the overall extraction curve fitted to a spline linear model. The effects of temperature (30, 50, and 70 °C), pressure (25, 40, and 55 MPa), and the percentage of co-solvent (0, 25%, and 50% v/v ethanol) on SFE were analyzed, resulting in the co-solvent and temperature as the most significant factors followed by the pressure. Under 70 °C, 40 MPa, and 50% v/v ethanol, C. onubensis reached a maximum of 66.98% of LR. The extracts were richest in total phenols and showed the maximum antioxidant activity (36.08 mg GAEs/g extracts and 2.237 mmol TE/g extracts, respectively) under similar pressure and co-solvent percentage values and different temperatures (30 and 70 °C, respectively). The extracts obtained in this study may have potential applications in the food, nutraceutical, and cosmetic industries. SFE is a highly efficient method to valorize microorganisms living in extreme environments, which are so far unexplored using green extraction methods.

17.
Curr Eye Res ; 47(7): 1061-1067, 2022 07.
Artigo em Inglês | MEDLINE | ID: mdl-35438020

RESUMO

PURPOSE: To quantify visual and retinal changes in patients with bipolar disorder (BD) over 5 years, compared with controls. METHODS: Thirty-eight patients with BD and 122 healthy subjects underwent visual acuity (VA) evaluation, contrast sensitivity vision testing (CSV) with the Pelli Robson and CSV 1000E tests, and retinal thicknesses measurement [ganglion cell layer (GCL) and retinal nerve fiber layer (RNFL)] using Spectralis Optical Coherence Tomography (OCT). All subjects were re-evaluated after 5 years. The relationship between progressive structural changes and disease duration was analyzed. RESULTS: Visual function parameters in BD patients remained unchanged during the follow-up period. A progressive decrease affecting macular and peripapillary RNFL thickness (p < 0.050) was observed in patients. Progressive changes in BD were more pronounced when compared with healthy controls (p < 0.050). A significant correlation between GCL thickness changes and disease duration was found (GCL outer temporal, r = -0.680, p = 0.016; GCL central, r = -0.540, p = 0.038). CONCLUSIONS: Progressive axonal loss was detected in BD patients. Visual function parameters were not affected after the 5-year follow-up. Despite observed changes in the neuroretina of patients with BD, axonal degeneration in these patients seemed to be mild and might be slowed down by other factors, such as BD treatments.


Assuntos
Transtorno Bipolar , Degeneração Retiniana , Transtorno Bipolar/diagnóstico , Humanos , Fibras Nervosas , Degeneração Retiniana/diagnóstico , Degeneração Retiniana/etiologia , Células Ganglionares da Retina , Tomografia de Coerência Óptica/métodos
18.
PeerJ ; 9: e12195, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34631319

RESUMO

The fall armyworm, Spodoptera frugiperda, is a polyphagous global pest with a preference for gramineous crops such as corn, sorghum and pasture grasses. This species is comprised of two morphologically identical but genetically distinct host strains known as the corn and rice strains, which can complicate pest management approaches. Two molecular markers are commonly used to differentiate between strains, however, discordance between these markers can lead to inconclusive strain identification. Here, we used double digest restriction site associated DNA sequencing to identify diagnostic single nucleotide polymorphisms (SNPs) with alleles unique to each strain. We then used these strain-specific SNPs to develop four real-time PCR based TaqMan assays to rapidly and reliably differentiate between strains and interstrain hybrids. These assays provide a new tool for differentiating between strains in field-collected samples, facilitating future studies on strain population dynamics and interstrain hybridization rates. Understanding the basic ecology of S. frugiperda strains is necessary to inform future management strategies.

19.
Genes (Basel) ; 12(10)2021 09 28.
Artigo em Inglês | MEDLINE | ID: mdl-34680917

RESUMO

Members of the insect ATP binding cassette transporter subfamily C2 (ABCC2) in several moth species are known as receptors for the Cry1Ac insecticidal protein from Bacillus thuringiensis (Bt). Mutations that abolish the functional domains of ABCC2 are known to cause resistance to Cry1Ac, although the reported levels of resistance vary widely depending on insect species. In this study, the function of the ABCC2 gene as a putative Cry1Ac receptor in Helicoverpa zea, a major pest of over 300 crops, was evaluated using CRISPR/Cas9 to progressively eliminate different functional ABCC2 domains. Results from bioassays with edited insect lines support that mutations in ABCC2 were associated with Cry1Ac resistance ratios (RR) ranging from 7.3- to 39.8-fold. No significant differences in susceptibility to Cry1Ac were detected between H. zea with partial or complete ABCC2 knockout, although the highest levels of tolerance were observed when knocking out half of ABCC2. Based on >500-1000-fold RRs reported in similar studies for closely related moth species, the low RRs observed in H. zea knockouts support that ABCC2 is not a major Cry1Ac receptor in this insect.


Assuntos
Toxinas de Bacillus thuringiensis/toxicidade , Endotoxinas/toxicidade , Proteínas Hemolisinas/toxicidade , Proteínas de Insetos/genética , Resistência a Inseticidas , Lepidópteros/metabolismo , Proteínas Associadas à Resistência a Múltiplos Medicamentos/genética , Animais , Deleção de Genes , Proteínas de Insetos/metabolismo , Lepidópteros/efeitos dos fármacos , Lepidópteros/genética , Proteínas Associadas à Resistência a Múltiplos Medicamentos/metabolismo
20.
Insects ; 12(7)2021 Jul 08.
Artigo em Inglês | MEDLINE | ID: mdl-34357278

RESUMO

Evolution of practical resistance is the main threat to the sustainability of transgenic crops producing insecticidal proteins from Bacillus thuringiensis (Bt crops). Monitoring of resistance to Cry and Vip3A proteins produced by Bt crops is critical to mitigate the development of resistance. Currently, Cry/Vip3A resistance allele monitoring is based on bioassays with larvae from inbreeding field-collected moths. As an alternative, DNA-based monitoring tools should increase sensitivity and reduce overall costs compared to bioassay-based screening methods. Here, we evaluated targeted sequencing as a method allowing detection of known and novel candidate resistance alleles to Cry proteins. As a model, we sequenced a Cry1F receptor gene (SfABCC2) in fall armyworm (Spodoptera frugiperda) moths from Puerto Rico, a location reporting continued practical field resistance to Cry1F-producing corn. Targeted sequencing detected a previously reported Cry1F resistance allele (SfABCC2mut), in addition to a resistance allele originally described in S. frugiperda populations from Brazil. Moreover, targeted sequencing detected mutations in SfABCC2 as novel candidate resistance alleles. These results support further development of targeted sequencing for monitoring resistance to Bt crops and provide unexpected evidence for common resistance alleles in S. frugiperda from Brazil and Puerto Rico.

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