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1.
Pestic Biochem Physiol ; 202: 105958, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38879340

RESUMO

The wheat aphid Sitobion miscanthi is a dominant and destructive pest in agricultural production. Insecticides are the main substances used for effective control of wheat aphids. However, their extensive application has caused severe resistance of wheat aphids to some insecticides; therefore, exploring resistance mechanisms is essential for wheat aphid management. In the present study, CYP6CY2, a new P450 gene, was isolated and overexpressed in the imidacloprid-resistant strain (SM-R) compared to the imidacloprid-susceptible strain (SM-S). The increased sensitivity of S. miscanthi to imidacloprid after knockdown of CYP6CY2 indicates that it could be associated with imidacloprid resistance. Subsequently, the posttranscriptional regulation of CYP6CY2 in the 3' UTR by miR-3037 was confirmed, and CYP6CY2 participated in imidacloprid resistance. This finding is critical for determining the role of P450 in relation to the resistance of S. miscanthi to imidacloprid. It is of great significance to understand this regulatory mechanism of P450 expression in the resistance of S. miscanthi to neonicotinoids.


Assuntos
Afídeos , Sistema Enzimático do Citocromo P-450 , Resistência a Inseticidas , Inseticidas , MicroRNAs , Neonicotinoides , Nitrocompostos , Neonicotinoides/farmacologia , Nitrocompostos/farmacologia , Animais , Inseticidas/farmacologia , Resistência a Inseticidas/genética , Afídeos/genética , Afídeos/efeitos dos fármacos , MicroRNAs/genética , MicroRNAs/metabolismo , Sistema Enzimático do Citocromo P-450/genética , Sistema Enzimático do Citocromo P-450/metabolismo , Proteínas de Insetos/genética , Proteínas de Insetos/metabolismo , Imidazóis/farmacologia
2.
J Econ Entomol ; 2024 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-38856713

RESUMO

Sitobion miscanthi and Schizaphis graminum (Rondani) are the 2 main aphid species that occur simultaneously, causing significant loss to wheat production. Acetamiprid has been used to control a variety of pests, including aphids. In this study, the sublethal effect of acetamiprid on S. miscanthi and S. graminum was evaluated using life-table analyses. The results showed that acetamiprid has a high toxicity to S. miscanthi and S. graminum with a LC50 of 1.90 and 3.58 mg/L at 24 h, respectively. The adult longevity and fecundity of S. miscanthi and S. graminum F0 generation were significantly reduced after being exposed to a sublethal concentration of acetamiprid. Additionally, the sublethal concentration of acetamiprid had negative transgenerational effects on S. miscanthi and S. graminum, which showed a significant decrease in fecundity and population life-table parameters involving age-stage-specific survival rate (sxj), age-specific survival rate (lx), and intrinsic rate of increase (r). Furthermore, the population projections showed that the total population size of S. miscanthi and S. graminum was significantly lower in the aphid group exposed to sublethal concentration of acetamiprid compared to the control group. These results suggest that sublethal concentration of acetamiprid suppresses the population growth of S. miscanthi and S. graminum. This finding is beneficial to the control of wheat aphids, and is important to fully understand the role of acetamiprid in integrated pest management.

3.
PLoS One ; 18(11): e0294877, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-38011174

RESUMO

Imidacloprid is a neonicotinoid insecticide that efficiently controls piercing-sucking mouthparts pests. However, the impact of low lethal concentration of imidacloprid on key demographic parameters of wheat aphids, Schizaphis graminum (R.) and Rhopalosiphum padi (L.) has been scarcely studied. In this study, we used the age stage, two-sex life table approach to investigate the sublethal effects of imidacloprid on the biological traits of S. graminum and R. padi. Bioassays showed that imidacloprid possesses high toxicity to adult S. graminum and R. padi, with LC50 of 3.59 and 13.78 mg L-1 following 24 h exposure. A low lethal concentration of imidacloprid (LC25) significantly decreased adult longevity and total longevity of progeny generation aphids (F1) of S. graminum. Nevertheless, imidacloprid (LC25) had no significant effects on the fecundity and longevity of directly exposed parental parental S. graminum and R. padi (F0). Our results showed that the low lethal concentration of imidacloprid affected the demographic parameters that ultimately impact on the population of S. graminum. This study provides detailed information about the overall effects of imidacloprid on S. graminum and R. padi that might help to manage these two key pests.


Assuntos
Afídeos , Inseticidas , Animais , Neonicotinoides/toxicidade , Fertilidade , Inseticidas/toxicidade
4.
Environ Microbiome ; 18(1): 78, 2023 Oct 24.
Artigo em Inglês | MEDLINE | ID: mdl-37876011

RESUMO

BACKGROUND: Leaf-associated microbes play an important role in plant development and response to exogenous stress. Insect herbivores are known to alter the phyllosphere microbiome. However, whether the host plant's defense against insects is related to the phyllosphere microbiome remains mostly elusive. Here, we investigated bacterial communities in the phyllosphere and endosphere of eight wheat cultivars with differing aphid resistance, grown in the same farmland. RESULTS: The bacterial community in both the phyllosphere and endosphere showed significant differences among most wheat cultivars. The phyllosphere was connected to more complex and stable microbial networks than the endosphere in most wheat cultivars. Moreover, the genera Pantoea, Massilia, and Pseudomonas were found to play a major role in shaping the microbial community in the wheat phyllosphere. Additionally, wheat plants showed phenotype-specific associations with the genera Massilia and Pseudomonas. The abundance of the genus Exiguobacterium in the phyllosphere exhibited a significant negative correlation with the aphid hazard grade in the wheat plants. CONCLUSION: Communities of leaf-associated microbes in wheat plants were mainly driven by the host genotype. Members of the genus Exiguobacterium may have adverse effects on wheat aphids. Our findings provide new clues supporting the development of aphid control strategies based on phyllosphere microbiome engineering.

5.
Eur Spine J ; 32(12): 4238-4245, 2023 12.
Artigo em Inglês | MEDLINE | ID: mdl-37689612

RESUMO

PURPOSE: The study evaluated the diagnostic performance of metagenomic next-generation sequencing (mNGS) as a diagnostic test for biopsy samples from patients with suspected spinal infection (SI) and compared the diagnostic performance of mNGS with that of microbial culture. METHODS: All patients diagnosed with clinical suspicion of SI were enrolled, and data were collected through a retrospective chart review of patient records. Biopsy specimens obtained from each patient were tested via mNGS and microbial culture. Samples were enriched for microbial DNA using the universal DNA extraction kit, whole-genome amplified, and sequenced using MGISEQ-200 instrument. After Low-quality reads removed, the remaining sequences for microbial content were analyzed and aligned using SNAP and kraken2 tools. RESULTS: A total of 39 patients (19 men and 20 women) were deemed suitable for enrollment. The detection rate for pathogens of mNGS was 71.8% (28/39), which was significantly higher than that of microbial culture (23.1%, p = 0.016). Mycobacterium tuberculosis complex was the most frequently isolated. Using pathologic test as the standard reference for SI, thirty-one cases were classified as infected, and eight cases were considered aseptic. The sensitivity and specificity values for detecting pathogens with mNGS were 87.1% and 87.5%, while these rates were 25.8% and 87.5% with conventional culture. mNGS was able to detect 88.9% (8/9) of pathogens identified by conventional culture, with a genus-level sensitivity of 100% (8/8) and a species-level sensitivity of 87.5% (7/8). CONCLUSION: The present work suggests that mNGS might be superior to microbial culture for detecting SI pathogens.


Assuntos
Afeto , Sequenciamento de Nucleotídeos em Larga Escala , Masculino , Humanos , Feminino , Estudos Retrospectivos , DNA , Sensibilidade e Especificidade
7.
Reprod Biol Endocrinol ; 21(1): 53, 2023 Jun 09.
Artigo em Inglês | MEDLINE | ID: mdl-37296437

RESUMO

BACKGROUND: Sertoli cell-only syndrome (SCOS) is the most serious pathological type of non-obstructive azoospermia. Recently, several genes related to SCOS have been identified, including FANCM, TEX14, NR5A1, NANOS2, PLK4, WNK3, and FANCA, but they cannot fully explain the pathogenesis of SCOS. This study attempted to explain spermatogenesis dysfunction in SCOS through testicular tissue RNA sequencing and to provide new targets for SCOS diagnosis and therapy. METHODS: We analyzed differentially expressed genes (DEGs) based on RNA sequencing of nine patients with SCOS and three patients with obstructive azoospermia and normal spermatogenesis. We further explored the identified genes using ELISA and immunohistochemistry. RESULTS: In total, 9406 DEGs were expressed (Log2|FC|≥ 1; adjusted P value < 0.05) in SCOS samples, and 21 hub genes were identified. Three upregulated core genes were found, including CASP4, CASP1, and PLA2G4A. Thus, we hypothesized that testis cell pyroptosis mediated by CASP1 and CASP4 might be involved in SCOS occurrence and development. ELISA verified that CASP1 and CASP4 activities in the testes of patients with SCOS were significantly higher than those in patients with normal spermatogenesis. Immunohistochemical results showed that CASP1 and CASP4 in the normal spermatogenesis group were mainly expressed in the nuclei of spermatogenic, Sertoli, and interstitial cells. CASP1 and CASP4 in the SCOS group were mainly expressed in the nuclei of Sertoli and interstitial cells because of the loss of spermatogonia and spermatocytes. CASP1 and CASP4 expression levels in the testes of patients with SCOS were significantly higher than those in patients with normal spermatogenisis. Furthermore, the pyroptosis-related proteins GSDMD and GSDME in the testes of patients with SCOS were also significantly higher than those in control patients. ELISA also showed that inflammatory factors (IL-1 ß, IL-18, LDH, and ROS) were significantly increased in the SCOS group. CONCLUSIONS: For the first time, we found that cell pyroptosis-related genes and key markers were significantly increased in the testes of patients with SCOS. We also observed many inflammatory and oxidative stress reactions in SCOS. Thus, we propose that testis cell pyroptosis mediated by CASP1 and CASP4 could participate in SCOS occurrence and development.


Assuntos
Azoospermia , Síndrome de Células de Sertoli , Masculino , Humanos , Testículo/metabolismo , Síndrome de Células de Sertoli/genética , Síndrome de Células de Sertoli/metabolismo , Síndrome de Células de Sertoli/patologia , Azoospermia/patologia , Piroptose/genética , Espermatogênese/genética , Proteínas Serina-Treonina Quinases/metabolismo , DNA Helicases/metabolismo , Fatores de Transcrição/metabolismo
8.
Drug Resist Updat ; 68: 100962, 2023 05.
Artigo em Inglês | MEDLINE | ID: mdl-37068396

RESUMO

Castration-resistant prostate cancer (CRPC), especially metastatic castration-resistant prostate cancer (mCRPC) is one of the most prevalent malignancies and main cause of cancer-related death among men in the world. In addition, it is very difficult for clinical treatment because of the natural or acquired drug resistance of CRPC. Mechanisms of drug resistance are extremely complicated and how to overcome it remains an urgent clinical problem to be solved. Thus, a comprehensive and thorough understanding for mechanisms of drug resistance in mCRPC is indispensable to develop novel and better therapeutic strategies. In this review, we aim to review new insight of the treatment of mCRPC and elucidate mechanisms governing resistance to new drugs: taxanes, androgen receptor signaling inhibitors (ARSIs) and poly (ADP-ribose) polymerase (PARP) inhibitors (PARPi). Most importantly, in order to improve efficacy of these drugs, strategies of overcoming drug resistance are also discussed based on their mechanisms respectively.


Assuntos
Neoplasias de Próstata Resistentes à Castração , Masculino , Humanos , Neoplasias de Próstata Resistentes à Castração/tratamento farmacológico , Neoplasias de Próstata Resistentes à Castração/genética , Neoplasias de Próstata Resistentes à Castração/patologia , Resistencia a Medicamentos Antineoplásicos , Taxoides , Transdução de Sinais
9.
Front Physiol ; 14: 1113464, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36818440

RESUMO

Field populations of insect pests are affected by sub-lethal doses of insecticides, leading to hormesis. Imidacloprid is a neonicotinoid insecticide widely used to control various sucking insect pests, including aphids. In this study, the effects of sub-lethal concentrations of imidacloprid on the life table traits of the rose-grain aphid Metopolophium dirhodum (Walker) were evaluated on parental and first filial generations. The results showed that sub-lethal concentrations of imidacloprid significantly reduced the fecundity, adult longevity, and reproductive period of M. dirhodum in parental generation (F0). However, the imidacloprid-induced hormetic effects on development and reproduction were detected in the F1 generation. These hormetic effects were indicated by significantly higher adult longevity, fecundity, survival rate, intrinsic and finite rates of increase, and net reproductive rate of first filial generation (F1) of M. dirhodum. Our finding indicated that the application of sub-lethal concentrations of imidacloprid inhibited parental generation (F0), but it significantly stimulated the population growth of filial generation (F1) in the M. dirhodum. The results support the inclusion of insecticides in integrated pest management programs for managing wheat aphids.

10.
Insects ; 14(1)2023 Jan 12.
Artigo em Inglês | MEDLINE | ID: mdl-36662003

RESUMO

Sulfoxaflor belongs to a new class of insecticides that is effective against many sap-feeding pests. In this study on Sitobion miscanthi (Takahashi) (i.e., the predominant wheat pest), a highly sulfoxaflor-resistant (SulR) population was obtained from a field. Its resistance to the other seven insecticides and its biological fitness were analyzed using a leaf-dip method and a two-sex life table approach, respectively. Compared with the relatively susceptible (SS) population, the SulR population was highly resistant to sulfoxaflor, with a relative insecticide resistance ratio (RR) of 199.8 and was moderately resistant to beta-cypermethrin (RR = 14.5) and bifenthrin (RR = 42.1) but exhibited low resistance to chlorpyrifos (RR = 5.7). Additionally, the SulR population had a relative fitness of 0.73, with a significantly prolonged developmental period as well as a lower survival rate and poorer reproductive performance than the SS population. In conclusion, our results suggest that S. miscanthi populations that are highly resistant to sulfoxaflor exist in the field. The possibility that insects may develop multi-resistance between sulfoxaflor and pyrethroids is a concern. Furthermore, the high sulfoxaflor resistance of S. miscanthi was accompanied by a considerable fitness cost. The study data may be useful for improving the rational use of insecticides and for exploring novel insecticide resistance mechanisms.

11.
Pest Manag Sci ; 79(4): 1362-1371, 2023 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-36458953

RESUMO

BACKGROUND: Symbiotic bacteria affect physiology and ecology of insect hosts. The Sitobion miscanthi L type symbiont (SMLS) is a recently discovered and widely distributed secondary symbiont in the grain aphid Sitobion miscanthi Takahashi in China. RESULTS: In this study, SMLS-infected (SI) and SMLS-uninfected (SU) aphid strains were obtained from field population. The artificially SMLS-re-infected (SRI) strain was established by injecting SU aphids with the SI strain hemolymph containing SMLS. The SRI and SU strains had identical genetic backgrounds and similar microbial community structures. Compared with the SU strain, adult longevity, survival rate, and fecundity were significantly greater in the SRI strain (biological fitness of 1.48). Moreover, the SRI strain spent more time ingesting phloem than the SU strain. A comparative transcriptome analysis indicated that reproduction- and longevity-related genes were more highly expressed in the SRI strain than in the SU strain. CONCLUSION: The findings indicated that the infection with SMLS enhanced the Sitobion miscanthi fitness and feeding behavior. The beneficial effect of the SMLS on hosts could explain why it frequently infects the field populations in the grain aphid Sitobion miscanthi Takahashi in China. © 2022 Society of Chemical Industry.


Assuntos
Afídeos , Animais , Afídeos/fisiologia , Bactérias , Comportamento Alimentar , China , Simbiose/fisiologia
12.
Reprod Sci ; 30(5): 1594-1607, 2023 05.
Artigo em Inglês | MEDLINE | ID: mdl-36333644

RESUMO

Intrauterine growth restriction (IUGR) increases the risk of type 2 diabetes mellitus (T2DM) and metabolic diseases. The pancreas of fetuses with IUGR is usually characterized by pancreatic dysplasia and reduced levels of insulin secretion caused by the diminished replication of ß-cells. Previous studies showed that a low dose of ouabain could reduce the apoptosis of embryonic nephric cells during IUGR and partially restore the number of nephrons at birth. The rescued kidneys functioned well and decreased the prevalence of hypertension. Thus, we hypothesized that ouabain could rescue pancreatic development during IUGR and reduce the morbidity of T2DM and metabolic diseases. Maternal malnutrition was used to induce the IUGR model, and then a low dose of ouabain was administered to rats with IUGR during pregnancy. Throughout the experiment, we monitored the pattern of weight increase and evaluated the metabolic parameters in the offspring in different stages. Male, but not female, offspring in the IUGR group presented catch-up growth. Ouabain could benefit the impaired glucose tolerance of male offspring; however, this desirable effect was eliminated by aging. The insulin sensitivity was significantly impaired in male offspring with IUGR, but it was improved by ouabain, even during old age. However, in the female offspring, low birth weight appeared to be a beneficial factor even in old age; administering ouabain exacerbated these favorable effects. Our data suggested that IUGR influenced glucose metabolism in a sex-specific manner and ouabain treatment during pregnancy exerted strongly contrasting effects in male and female rats.


Assuntos
Diabetes Mellitus Tipo 2 , Retardo do Crescimento Fetal , Gravidez , Feminino , Humanos , Ratos , Animais , Masculino , Retardo do Crescimento Fetal/metabolismo , Ouabaína/farmacologia , Ratos Sprague-Dawley , Diabetes Mellitus Tipo 2/complicações , Metaboloma
13.
Environ Res ; 215(Pt 2): 114409, 2022 12.
Artigo em Inglês | MEDLINE | ID: mdl-36152886

RESUMO

Insect-associated bacteria play an important role in the resistance to pesticides, yet bacterial community compositions in wild insect host populations and the environmental factors that shape them are mostly elusive. In this study, Sitobion miscanthi (Takahashi) populations were collected from major wheat growing regions in China. Following high-throughput sequencing of 16S rRNA gene fragments, association analyses were performed within the bacterial community associated with S. miscanthi, as well as with population resistance levels to four commonly used pesticides and different environmental factors. We found that bacterial community structures differed in various regions, and that the abundances of dominant bacteria such as Buchnera, Candidatus Regiella, Candidatus Hamiltonella showed high variations. The resistance of S. miscanthi to avermectin and bifenthrin was shown to decline with increasing bacterial diversity. Meanwhile, with the increase of bacterial network modularity, the resistance of S. miscanthi populations to imidacloprid, avermectin and bifenthrin also increased correspondingly. In addition, correlation analysis indicated that altitude and air pressure had the strongest impact on bacterial community diversity and relative abundance, followed by humidity, rainfall and temperature. Overall, insights into such complex interactions between bacteria and their insect hosts offer new directions for biological pest control.


Assuntos
Afídeos , Microbiota , Praguicidas , Animais , Afídeos/genética , Afídeos/microbiologia , Bactérias/genética , Enterobacteriaceae , Resistência a Inseticidas , Ivermectina/análogos & derivados , Piretrinas , RNA Ribossômico 16S/genética
14.
Transl Pediatr ; 11(5): 766-773, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35685080

RESUMO

Background: Upshaw-Schulman syndrome (USS) is rare, autosomal recessive, hereditary thrombotic thrombocytopenic purpura (TTP) caused by variants in a disintegrin-like and metalloprotease with thrombospondin type 1 motif (ADAMTS13). USS has a heterogeneous clinical course, and most symptoms overlap with other diseases. Early diagnosis may have important implications for the patients. We found novel ADAMTS13 mutation and explored the clinical features and prognosis of newborn-onset USS to increase awareness of the disease. Case Description: The same, non-consanguineous couple had three unexplained neonatal deaths. The symptoms of the three infants were mainly severe jaundice, anemia and thrombocytopenia after birth, which was consistent with the reported USS symptoms of neonates and died rapidly suddenly in the during rescue efforts. By using whole-exome sequencing (WES) for the study family, we found a novel heterozygous compound in ADAMTS13 (c.1187 (exon10) G>A (p.C396Y)/c.1595 (exon14) G>T (p.C532F)) that was carried by the three newborns originating from father and mother respectively. We reviewed nine published studies of newborn-onset USS and compared our cases for clinical symptoms and laboratory testing. All nine published cases were diagnosed by ADAMTS13 activity; in seven cases gene mutation analysis was performed and eight cases were still alive at the time of publication. Conclusions: The case has added clinicians' awareness of the diagnosis and treatment of USS. A novel rare mutation in ADAMTS13 broadens the spectrum of genetic causes of this rare disorder and expands the phenotypic spectrum.

16.
J Econ Entomol ; 115(1): 313-324, 2022 02 09.
Artigo em Inglês | MEDLINE | ID: mdl-34850027

RESUMO

The English grain aphid, Sitobion avenae (Fabricius), exhibits classic and dramatic phenotypic plasticity in wing development. Both genetic and environmental inputs contribute to the wing polyphenism in aphids, an extreme form of phenotypic plasticity in which a single genotype produces discrete winged and wingless morphs. Validated reference genes are needed to accurately normalize temporal and spatial variation in gene expression estimates by RT-qPCR. In this research, the stability of 11 candidate reference genes selected from S. avenae transcriptomes was evaluated under an array of abiotic and biotic conditions relevant to wing development. RefFinder, a comprehensive software integrating rankings from delta Ct, BestKeeper, NormFinder, and geNorm, offered a series of reference genes for every experimental condition. Overall, helicase (HEL) and ubiquitin ribosomal protein S27A fusion protein (RpS27) are suited for most of the conditions examined in this study, although exceptions do exist. Specifically, NADH dehydrogenase (Ap-NADH) and 28S ribosomal RNA (28S) are recommended for insecticide and antibiotic treatments, while ribosomal RNA L14 (RPL14) and 18S ribosomal RNA (18S) are selected for density treatment, respectively. This study provides a suite of reference genes to investigate the wing polyphenism in S. avenae, and is important for application of RT-qPCR in future experiments of novel tactics to control aphids.


Assuntos
Afídeos , Animais , Genótipo , Reação em Cadeia da Polimerase em Tempo Real , Caracteres Sexuais , Asas de Animais
17.
Front Physiol ; 12: 663338, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33935809

RESUMO

Rhopalosiphum padi (L.) (Hemiptera: Aphididae) is an important cosmopolitan pest in cereal crops. Reference genes can significantly affect qRT-PCR results. Therefore, selecting appropriate reference genes is a key prerequisite for qRT-PCR analyses. This study was conducted to identify suitable qRT-PCR reference genes in R. padi. We systematically analyzed the expression profiles of 11 commonly used reference genes. The ΔCt method, the BestKeeper, NormFinder, geNorm algorithms, and the RefFinder online tool were used to evaluate the suitability of these genes under diverse experimental conditions. The data indicated that the most appropriate sets of reference genes were ß-actin and GAPDH (for developmental stages), AK and TATA (for populations), RPS18 and RPL13 (for tissues), TATA and GAPDH (for wing dimorphism), EF-1α and RPS6 (for antibiotic treatments), GAPDH and ß-actin (for insecticide treatments), GAPDH, TATA, RPS18 (for starvation-induced stress), TATA, RPS6, and AK (for temperatures), and TATA and GAPDH (for all conditions). Our study findings, which revealed the reference genes suitable for various experimental conditions, will facilitate the standardization of qRT-PCR programs, while also improving the accuracy of qRT-PCR analyses, with implications for future research on R. padi gene functions.

18.
Chemosphere ; 269: 128747, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33172670

RESUMO

Rhopalosiphum padi (Linnaeus) and Sitobion avenae (Fabricius) are the predominant pests coexisting on wheat plants. In this study, the susceptibilities of 29 R. padi and 30 S. avenae populations from 15 provinces in China to pyrethroids (beta-cypermethrin and bifenthrin), neonicotinoids (imidacloprid and thiamethoxam), organophosphates (omethoate and chlorpyrifos) and macrolides (avermectin) were determined during 2018-2019. The median lethal insecticide concentrations (LC50) indicated that R. padi was more sensitive than S. avenae to most of the insecticides. Monitor results showed that most wheat aphid populations were moderately resistant to pyrethroids. Two R. padi populations were highly resistant to beta-cypermethrin with 127.3-fold and 442.8-fold resistance ratio (RR), and two were highly resistant to bifenthrin (RR of 293.9 and 320.6, respectively). One S. avenae population was highly resistant to beta-cypermethrin (RR of 136.8) and one was highly resistant to bifenthrin (RR of 313.4). All populations of two wheat aphids exhibited low to moderate resistance to neonicotinoids (RR < 100). But over half populations were sensitive or exhibited low resistance to organophosphates and macrolides. The pair-wise correlation coefficients for the insecticide LC50 revealed a positive correlation between beta-cypermethrin and bifenthrin resistance, as well as between the resistance to bifenthrin and omethoate for the two-aphid species. Similarly, significant correlations were detected between the resistance to beta-cypermethrin and avermectin for R. padi. These results may be relevant for developing effective insecticide management strategies that prevent or delay the development of resistance among wheat aphids.


Assuntos
Afídeos , Piretrinas , Animais , China , Macrolídeos/farmacologia , Neonicotinoides , Organofosfatos/toxicidade , Piretrinas/toxicidade
19.
Sci Rep ; 10(1): 21951, 2020 12 15.
Artigo em Inglês | MEDLINE | ID: mdl-33319828

RESUMO

Metopolophium dirhodum (Walker) (Hemiptera: Aphididae) is one of the most common aphid pests of winter cereals. To facilitate accurate gene expression analyses with qRT-PCR assays, the expression stability of candidate reference genes under specific experimental conditions must be verified before they can be used to normalize target gene expression levels. In this study, 10 candidate reference genes in M. dirhodum were analyzed by qRT-PCR under various experimental conditions. Their expression stability was evaluated with delta Ct, BestKeeper, geNorm, and NormFinder methods, and the final stability ranking was determined with RefFinder. The results indicate that the most appropriate sets of internal controls were SDHB and RPL8 across geographic population; RPL8, Actin, and GAPDH across developmental stage; SDHB and NADH across body part; RPL8 and Actin across wing dimorphism and temperature; RPL4 and EF1A across starvation stress; AK and RPL4 across insecticide treatments; RPL8 and NADH across antibiotic treatments; RPL8, RPL4, Actin, and NADH across all samples. The results of this study provide useful insights for establishing a standardized qRT-PCR procedure for M. dirhodum and may be relevant for identifying appropriate reference genes for molecular analyses of related insects.


Assuntos
Afídeos/genética , Genes de Insetos , Reação em Cadeia da Polimerase Via Transcriptase Reversa/métodos , Seleção Genética , Algoritmos , Animais , Afídeos/crescimento & desenvolvimento , Perfilação da Expressão Gênica/métodos , Inseticidas , Padrões de Referência , Reprodutibilidade dos Testes , Estresse Fisiológico/genética
20.
Opt Lett ; 45(15): 4324-4327, 2020 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-32735289

RESUMO

Metalenses are developing fast towards versatile and integrated terahertz (THz) apparatuses, while tunable ones are highly pursued. Here, we propose a strategy that integrates dielectric metasurfaces with liquid crystals (LCs) to realize the dynamic focal spot manipulation. The silicon pillar meta-units of the metasurface are properly selected to generate different phase profiles for two orthogonal linear polarizations, permitting a laterally or axially altered focal spot. After LCs integrated, polarization-multiplexed focusing can be achieved via electrically varying the LC orientations. We demonstrate two metalenses with distinct functions. For the first one, the uniformly aligned LC works as a polarization converter, and further switches the focal length by altering the bias. For the second one, an LC polarization grating is utilized for rear spin-selective beam deflection. Consequently, a THz port selector is presented. This work supplies a promising method towards active THz elements, which may be widely applied in THz sensing, imaging, and communication.

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