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LESSONS LEARNED: The efficacy of single-agent chemotherapy was not significantly different from that of double-agent chemotherapy in concurrent chemoradiotherapy for inoperable esophageal squamous cell carcinoma. Single-agent concurrent chemoradiotherapy had lower gastrointestinal and hematologic toxicity. Overall survival and progression-free survival were not significantly different between single- and double-agent concurrent chemoradiotherapy. BACKGROUND: This multicenter, randomized, phase II trial aimed to compare the efficacy and safety of single-agent concurrent chemoradiotherapy using the oral fluoropyrimidine S-1 with those of double-agent concurrent chemoradiotherapy using S-1 and cisplatin in patients with inoperable esophageal squamous cell carcinoma. METHODS: Patients with inoperable esophageal squamous cell carcinoma (clinical stages I to III) were randomly allocated to the single-agent group (S-1) or the double-agent group (S-1/cisplatin). The concurrent intensity-modulated radiation therapy plan was similar for both groups: planning target volume 1.8 Gy/f*30-33f and planning gross target volume of 2 Gy/f*30-33f. The primary outcome measure was the endoscopic complete response rate. RESULTS: Of the 105 patients randomized, 89 were assessable. The endoscopic complete response rate was 46.9% (23/49) in the single-agent group and 52.5% (21/40) in double-agent group. The median progression-free survival within a median follow-up of 23 months was 20 and 21 months, respectively. The median overall survival was 26 months and not reached, respectively. Grade 3 hematological toxicities occurred in 4.1% and 27.5% of the patients in the single- and the double-agent group, respectively. CONCLUSION: Single-agent chemotherapy in concurrent chemoradiotherapy for inoperable esophageal squamous cell carcinoma has good efficacy and safety, thus warranting a phase III trial.
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Neoplasias Esofágicas , Carcinoma de Células Escamosas de Esófago , Neoplasias de Cabeza y Cuello , Protocolos de Quimioterapia Combinada Antineoplásica/efectos adversos , Quimioradioterapia , Cisplatino/uso terapéutico , Neoplasias Esofágicas/tratamiento farmacológico , Neoplasias Esofágicas/radioterapia , Fluorouracilo/uso terapéutico , Humanos , Estudios ProspectivosRESUMEN
The diamondback moth, Plutella xylostella, is one of the most destructive pests worldwide and its management relies exclusively on frequent application of chemical insecticides. Resistance to common insecticides is now widespread, and novel classes of insecticides are needed. Entomopathogenic bacteria and their related products play an important role in the management of this pest. In the present work, one bacterial strain was separated from infected pupae of P. xylostella collected from field and its pathogenicity was evaluated. On the basis of the 16S ribosomal RNA sequencing, BLASTN, and phylogenetic analysis, this bacterial isolate was identified as Pseudomonas cedrina. Oral administration of P. cedrina at levels above 10,000 CFU/ml gave significant mortality to P. xylostella larvae. The pathogenicity was also observed by reduced longevity and fecundity in adult females. However, when live bacterial cells were removed, the cultured broth lost any pathogenicity. In response to the bacterial infection, P. xylostella expressed antimicrobial and stress-associated genes. A mixture treatment of P. cedrina and Bacillus thuringiensis showed an additive effect on larval mortality of P. xylostella. These results indicated that P. cedrina is an opportunistic entomopathogen without secretion of toxins. Furthermore, the additive effect of P. cedrina and B. thuringiensis provide a new insight to develop new strategy for controlling P. xylostella.
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Mariposas Nocturnas/microbiología , Pseudomonas/aislamiento & purificación , Animales , Femenino , Fertilidad , Perfilación de la Expresión Génica , Larva/microbiología , Longevidad , Mariposas Nocturnas/genética , Mariposas Nocturnas/metabolismo , Control Biológico de Vectores/métodos , Filogenia , Pseudomonas/clasificación , Pseudomonas/patogenicidad , Pupa/microbiología , ARN Ribosómico 16SRESUMEN
In a tritrophic context of plant-insect-entomopathogen, plants play important roles in modulating the interaction of insects and their pathogenic viruses. Currently, the influence of plants on the transmission of insect viruses has been mainly studied on baculoviruses and some RNA viruses, whereas the impact of plants on other insect viruses is largely unknown. Here, we identified a new densovirus infecting the green peach aphid Myzus persicae and tested whether and how host plants influence the transmission of the aphid densovirus. The complete single-stranded DNA genome of the virus, M. persicae densovirus 2, is 5 727 nt and contains inverted terminal repeats. Transcription and phylogenetic analysis indicated that the virus was distinct from other a few identified aphid densoviruses. The virus abundance was detected highly in the intestinal tract of aphids, compared with the lower level of it in other tissues including head, embryo, and epidermis. Cabbage and pepper plants had no obvious effect on the vertical transmission and saliva-mediated horizontal transmission of the virus. However, the honeydew-mediated horizontal transmission among aphids highly depended on host plants (65% on cabbages versus 17% on peppers). Although the virus concentration in the honeydew produced by aphids between 2 plants was similar, the honeydew production of the infected aphids reared on peppers was dramatically reduced. Taken together, our results provide evidence that plants influence the horizontal transmission of a new densovirus in an aphid population by modulating honeydew secretion of aphids, suggesting plants may manipulate the spread of an aphid-pathogenic densovirus in nature.
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Áfidos , Densovirus , Animales , Áfidos/genética , FilogeniaRESUMEN
The ideal operative timing for laparoscopic cholecystectomy (LC) remains controversial, particularly in emergency patients. This study aimed to evaluate the necessity of operative timing for emergency LC. One hundred ninety-four patients who had undergone operative timings were classified into groups of <72h and >72h from the onset of symptoms to the operation. Baseline data, basic disease, operative bleeding, complications, and conversion rates were analyzed by Variance analysis and logistic regression analysis. The total morbidity of postoperative complication was 4.93% and 3.84% (P = .751) in the <72h and >72h groups respectively. The complication and conversion to LC were mainly influenced by age and gallbladder volume (odds ratio [OR] = 1.078, P = .013, and OR = 1.035, P = .031), but not by operative timing (P = .292). The intraoperative blood loss was closely correlated with the gallbladder volume (OR = 1.019, P = .025) by logit regression analysis, and correlation coefficient of R = 0.436, P < .01. Our results suggest that it is not necessary to confine the operative timing of LC to within 72h from the onset of symptoms, and gallbladder volume should be emphasized in the operative timing for emergency LC.
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Colecistectomía Laparoscópica , Humanos , Colecistectomía Laparoscópica/efectos adversos , Colecistectomía Laparoscópica/métodos , Estudios Retrospectivos , Vesícula Biliar/cirugía , Pérdida de Sangre Quirúrgica , Complicaciones Posoperatorias/epidemiología , Complicaciones Posoperatorias/etiología , Complicaciones Posoperatorias/cirugíaRESUMEN
BACKGROUND: A significant variation in RNA interference (RNAi) efficiency hinders further functional gene studies and pest control application in many insects. The available double-stranded RNA (dsRNA) molecules introduced into the target cells are regarded as the crucial factor for efficient RNAi response. However, numerous studies have only focused on dsRNA stability in vivo; it is uncertain whether different dsRNA storage conditions in vitro play a role in variable RNAi efficiency among insects. RESULTS: A marker gene cardinal, which leads to white eyes when knocked-down in the red flour beetle Tribolium castaneum, was used to evaluate the effects of RNAi efficiency under different dsRNA storage conditions. We demonstrated that the dsRNA molecule is very stable under typical cryopreservation temperatures (-80 and -20 °C) within 180 days, and RNAi efficiency shows no significant differences under either low temperature. Unexpectedly, while dsRNA molecules were treated with multiple freeze-thaw cycles up to 50 times between -80/-20 °C and room temperature, we discovered that dsRNA integrity and RNAi efficiency were comparable with fresh dsRNA. Finally, when the stability of dsRNA was further measured under refrigerated storage conditions (4 °C), we surprisingly found that dsRNA is still stable within 180 days and can induce an efficient RNAi response as that of initial dsRNA. CONCLUSION: Our results indicate that dsRNA is extraordinarily stable under various temperature storage conditions that did not significantly impact RNAi efficiency in vivo insects. © 2022 Society of Chemical Industry.
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ARN Bicatenario , Tribolium , Animales , ARN Bicatenario/genética , Tribolium/genética , Interferencia de ARNRESUMEN
BACKGROUND: This study was operated to investigate the association between urinary albumin-to-creatinine ratio (ACR) and prehypertension among Chinese Han women. METHODS: Information on blood pressure measurement and other variables were obtained, and blood and urine samples collected in 1796 women aged ≥30 years. The association between urinary ACR and prehypertension were analyzed by using multivariate non-conditional logistic regression models. RESULTS: Average urinary ACR was higher in hypertensives than in prehypertensives (median: 15.54 vs 9.01 mg/g), and in prehypertensives than in normotensives (median: 9.01 vs 7.13 mg/g). Both systolic and diastolic blood pressures increased with urinary ACR. Compared with the lowest quartile of urinary ACR, multivariate adjusted odds ratios of prehypertension were 1.25 (95% confidence interval, 0.89-1.78), 1.95 (1.30-2.92) and 1.59 (1.02-2.48) for the second, third and fourth quartiles, respectively. After exclusion of subjects with diabetes or use of antihypertensive medication, the odds ratio of prehypertension still increased with urinary ACR levels. CONCLUSION: Increased urinary ACR was significantly and positively associated with prehypertension among Chinese Han women.
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Albuminuria/orina , Creatinina/orina , Prehipertensión/orina , Adulto , Anciano , Estudios Transversales , Diástole , Femenino , Humanos , Persona de Mediana Edad , SístoleRESUMEN
Gastric cancer (GC) is a heterogeneous disease; the tumor distribution and molecular subtype could affect the prognosis of patients with GC. However, the clinicopathological difference between GC in the lesser and that in the greater curvature remains unknown. In this study, we aimed to investigate the difference and provide new clues for the treatment of GC. Between January 2010 and August 2014, 1249 consecutive patients with GC in the lesser or greater curvature were treated in our surgery department; data related to the demographic characteristics, pathological type, tumor grade, tumor size, TNM stage, tumor markers, operative methods, complications, and follow-up were retrospectively analyzed using a univariate analysis and the Kaplan-Meier method. The tumor size in lesser curvature was larger than that in the greater curvature (4.95 ± 2.57 vs 4.43 ± 2.62 cm, P = .034); patients with GC in the lesser curvature had a higher incidence of total gastrectomy and a lower incidence of distal gastrectomy than those with GC in the greater curvature (60.2% vs 43.2%, and 34.8% vs 49.2%, P = .002). No significant differences were found in the 5-year survival rate between patients with GC in the greater curvature and those with GC in the lesser curvature (62.6% vs 66.1%, P = .496). The epidermal growth factor receptor (EGFR) expression rate of tumors in the lesser curvature was 40.55%, which was significantly higher than that of tumors in the greater curvature (25.92%, P = .024), while the 5-year survival rate of patients with EGFR-positive expression was 50.8%, which was significantly lower than that of patients with EGFR-negative expression (64.8%, P = .021). Significant differences were observed in the clinicopathological features between GC in the lesser curvature and that in the greater curvature. These differences contribute to the improvement in the treatment outcome.
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Neoplasias Gástricas , Receptores ErbB , Gastrectomía/métodos , Humanos , Estadificación de Neoplasias , Pronóstico , Estudios Retrospectivos , Neoplasias Gástricas/patologíaRESUMEN
The ladybird Harmonia axyridis is an insect that exhibits pupal attachment to plants, which facilitates development and environmental adaptation. The cremaster is highly specialized for this behavior. However, the underlying molecular regulation of the cremaster remains unclear; therefore, we performed experiments to investigate the transcriptional regulation of cremaster development. First, we examined the morphological structure of the cremaster to reveal its function in pupal attachment of H. axyridis. Next, we analyzed the Hox gene Ha-Abd-B using RNA interference (RNAi) to determine its function in regulating cremaster formation; Ha-Abd-B up-regulation promoted effective pupal attachment, whereas successful RNAi caused severe down-regulation of this gene, and pupae were unable to attach. Furthermore, successful RNAi and subsequent Ha-Abd-B down-regulation caused phenotypic changes in cremaster structure, including its complete disappearance from some individuals. Finally, we observed unique development of the cremaster and dynamic expression of Ha-Abd-B during pre-pupal development; consequently, we hypothesized that there was specific pre-pupal development of the cremaster. Overall, based on these results, the specialized cremasteric structure located on the posterior side of H. axyridis was determined to be a key organ for pupal attachment. Cremaster identification in H. axyridis is regulated by Ha-Abd-B and exhibits preferential development. Pupal attachment of H. axyridis reveals an environmental adaptation of this species; thus, this study and future molecular studies will help determine the role of Hox genes in regulation of insect attachment and further our understanding of the multiple functions of Hox genes.
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Escarabajos , Proteínas de Homeodominio/genética , Abdomen/anatomía & histología , Animales , Escarabajos/anatomía & histología , Escarabajos/embriología , Escarabajos/genética , Escarabajos/fisiología , Regulación de la Expresión Génica , Larva/anatomía & histología , Larva/fisiología , Pupa/anatomía & histología , Pupa/fisiología , Interferencia de ARNRESUMEN
Phenotypic plasticity is observed in many animal species and it is effective for them to cope with many types of environmental threats. The multicolored Asian ladybird Harmonia axyridis shows a cuticular pigmentation plasticity that can be rapidly induced by temperature changes, and in the form of changeable melanin spot patterns to adjust heat-absorbing. Here, H. axyridis with thermal stimulation were selected for determining the molecular regulations behind it. First, we confirmed the melanin level changes of H. axyridis pupa could be induced by temperature, and then screened the efficient time window for thermal sensing of H. axyridis pre-pupa; it is suggested that the late stage of pre-pupa (late stage of 4th instar larva) is the critical period to sense thermal signals and adjust its pupal melanin spot area size to adapt to upcoming thermal conditions. The Ha-ADC (aspartate decarboxylase) and Ha-ebony (NBAD synthase) of aspartate-ß-alanine-NBAD pathway were then proved in regulation of cuticular melanization for pupa through RNA interference experiments; knockdown of these two genes enlarged the melanin spot size. Finally, we designed a random injection of Ha-ADC at different pre-pupal stages, to further study the regulation window during this process. Combined with all evidence observed, we suggested the spot size determination can be regulated very close to the time point of pupation, and genes of the aspartate-ß-alanine-NBAD pathway play an important role at the molecular level. In brief, H. axyridis exhibits a flexible active physiological regulation through transcriptional modification to thermal changes.
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Ácido Aspártico , Escarabajos , Melaninas , Pigmentación , beta-Alanina , Adaptación Fisiológica , Animales , Fenotipo , Pupa , TemperaturaRESUMEN
In insects, neuropeptides and their receptors not only play a critical role in insect physiology and behavior but also are the potential targets for novel pesticide discoveries. Aphidius gifuensis is one of the most important and widespread aphid parasitoids, and has been successfully used to control aphid. In the present work, we systematically identified neuropeptides and their receptors from the genome and head transcriptome of A. gifuensis. A total of 35 neuropeptide precursors and 49 corresponding receptors were identified. The phylogenetic analyses demonstrated that 35 of these receptors belong to family-A, four belong to family-B, two belong to leucine-rich repeat-containing GPCRs, four belong to receptor guanylyl cyclases, and four belong to receptor tyrosine kinases. Oral ingestion of imidacloprid significantly up-regulated five neuropeptide precursors and four receptors whereas three neuropeptide precursors and eight receptors were significantly down-regulated, which indicated that these neuropeptides and their receptors are potential targets of some commercial insecticides. The RT-qPCR results showed that dopamine receptor 1, dopamine receptor 2, octopamine receptor, allatostatin-A receptor, neuropeptides capa receptor, SIFamide receptor, FMRFamide receptor, tyramine receptor and short neuropeptide F predominantly were expressed in the head whilst the expression of ion transport peptide showed widespread distribution in various tissues. The high expression levels of these genes suggest their important roles in the central nervous system. Taken together, our study provides fundamental information that may further our understanding of neuropeptidergic signaling systems in the regulation of the physiology and behavior of solitary wasps. Furthermore, this information could also aid in the design and discovery of specific and environment-friendly insecticides.
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Maternal phenotypic regulations between different generations of aphid species help aphids to adapt to environmental challenges. The pea aphid Acyrthosiphon pisum has been used as a biological model for studies on phenotypic regulation for adaptation, and its alternative phenotypes are typically and physiologically based on maternal effects. We have observed an artificially induced and host-related maternal effect that may be a new aspect to consider in maternal regulation studies using A. pisum. Marked phenotypic changes in the cuticular melanization of daughter A. pisum were detected via tyrosine hydroxylase knockdown in the mothers during their period of host plants alternations. This phenotypic change was found to be both remarkable and repeatable. We performed several studies to understand its regulation and concluded that it may be controlled via the dopamine pathway. The downregulation and phenotypes observed were verified and described in detail. Additionally, based on histological and immunofluorescence analyses, the phenotypic changes caused by cuticular dysplasia were physiologically detected. Furthermore, we found that this abnormal development could not be reversed after birth. Transcriptome sequencing confirmed that this abnormal development represents a systemic developmental failure with numerous transcriptional changes, and chemical interventions suggested that transgenerational signals were not transferred through the nervous system. Our data show that transgenerational regulation (maternal effect) was responsible for the melanization failure. The developmental signals were received by the embryos from the mother aphids and were retained after birth. APTH RNAi disrupted the phenotypic determination process. We demonstrate that non-neuronal dopamine regulation plays a crucial role in the transgenerational phenotypic regulation of A. pisum. These results enhance our understanding of phenotyping via maternal regulation in aphids.
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RNA interference (RNAi) plays a key role in insect defense against viruses and transposable elements, and it is being applied as an experimental tool and for insect pest control. However, RNAi efficiency is highly variable for some insects, notably the pea aphid Acyrthosiphon pisum. In this study, we used natural variation in RNAi susceptibility of pea aphids to identify genes that influence RNAi efficiency. Susceptibility to orally-delivered dsRNA against the gut aquaporin gene AQP1 (ds-AQP1) varied widely across a panel of 83 pea aphid genotypes, from zero to total mortality. Genome-wide association between aphid performance on ds-AQP1 supplemented diet and aphid genetic variants yielded 103 significantly associated single nucleotide polymorphisms (SNPs), including variants in 55 genes, at the 10-4 probability cut-off. When ds-AQP1 was co-administered with dsRNA against six candidate genes, aphid mortality was reduced for three (50%) genes: the orthologs of the Drosophila genes trachealess (CG42865), headcase (CG15532) and a gene coding a peritrophin-A domain (CG8192), indicating that these genes function to promote RNAi efficiency against AQP1 in the pea aphid. Aphid susceptibility (quantified as mortality) to ds-AQP1 was correlated with RNAi against a further gene, snakeskin with essential gut function unrelated to AQP1, for some but not all aphid genotypes tested, suggesting that the determinants of RNAi efficiency may be partly gene-specific. This study demonstrates high levels of natural variation in susceptibility to RNAi and demonstrates the value of harnessing this variation to identify genes influencing RNAi efficiency.
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Áfidos/genética , Interferencia de ARN , Animales , Acuaporinas/efectos de los fármacos , Acuaporinas/genética , Acuaporinas/metabolismo , Genes de Insecto , Predisposición Genética a la Enfermedad , Estudio de Asociación del Genoma Completo , Proteínas de Insectos/genética , Proteínas de Insectos/metabolismo , Interferencia de ARN/fisiología , ARN Bicatenario/farmacología , ARN Interferente Pequeño/farmacologíaRESUMEN
Animals have developed numerous strategies to contend with environmental pressures. We observed that the same adaptation strategy may be used repeatedly by one species in response to a certain environmental challenge. The ladybird Harmonia axyridis displays thermal phenotypic plasticity at different developmental stages. It is unknown whether these superficially similar temperature-induced specializations share similar physiological mechanisms. We performed various experiments to clarify the differences and similarities between these processes. We examined changes in the numbers and sizes of melanic spots in pupae and adults, and confirmed similar patterns for both. The dopamine pathway controls pigmentation levels at both developmental stages of H. axyridis. However, the aspartate-ß-alanine pathway controls spot size and number only in the pupae. An upstream regulation analysis revealed the roles of Hox genes and elytral veins in pupal and adult spot formation. Both the pupae and the adults exhibited similar morphological responses to temperatures. However, they occurred in different body parts and were regulated by different pathways. These phenotypic adaptations are indicative of an effective thermoregulatory system in H. axyridis and explains how insects contend with certain environmental pressure based on various control mechanisms.
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BACKGROUND: The chitin biosynthesis pathway starts with trehalose in insects and the main functions of trehalases are hydrolysis of trehalose to glucose. Although insects possess two types, soluble trehalase (Tre-1) and membrane-bound trehalase (Tre-2), very little is known about Tre-2 and the difference in function between Tre-1 and Tre-2. RESULTS: To gain an insight into trehalase functions in insects, we investigated a putative membrane-bound trehalase from Spodoptera exigua (SeTre-2) cloned from the fat body. The deduced amino acid sequence of SeTre-2 contains 645 residues and has a predicted molecular weight of approximately 74 kDa and pI of 6.01. Alignment of SeTre-2 with other insect trehalases showed that it contains two trehalase signature motifs and a putative transmembrane domain, which is an important characteristic of Tre-2. Comparison of the genomic DNA and cDNA sequences demonstrated that SeTre-2 comprises 13 exons and 12 introns. Southern blot analysis revealed that S. exigua has two trehalase genes and that SeTre-2 is a single-copy gene. Northern blot analyses showed that the SeTre-2 transcript is expressed not only in the midgut, as previously reported for Bombyx mori, but also in the fat body and Malpighian tubules, although expression patterns differed between the midgut and fat body. SeTre-2 transcripts were detected in the midgut of feeding stage larvae, but not in pupae, whereas SeTre-2 mRNA was detected in the fat body of fifth instar larvae and pupae. CONCLUSION: These findings provide new data on the tissue distribution, expression patterns and potential function of membrane-bound trehalase. The results suggest that the SeTre-2 gene may have different functions in the midgut and fat body.
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Perfilación de la Expresión Génica , Proteínas de Insectos/metabolismo , Proteínas de la Membrana/metabolismo , Spodoptera/enzimología , Trehalasa/metabolismo , Secuencia de Aminoácidos , Animales , Secuencia de Bases , Northern Blotting , Southern Blotting , Exones/genética , Cuerpo Adiposo/metabolismo , Regulación del Desarrollo de la Expresión Génica , Regulación Enzimológica de la Expresión Génica , Proteínas de Insectos/clasificación , Proteínas de Insectos/genética , Intrones/genética , Proteínas de la Membrana/genética , Datos de Secuencia Molecular , Filogenia , ARN Mensajero/genética , ARN Mensajero/metabolismo , Alineación de Secuencia , Análisis de Secuencia de ADN , Homología de Secuencia de Aminoácido , Spodoptera/genética , Spodoptera/crecimiento & desarrollo , Trehalasa/clasificación , Trehalasa/genéticaRESUMEN
The chitin synthase (CHS) gene B (4781 bp) of Spodoptera exigua (SeCHSB) was cloned by reverse-transcription PCR (RT-PCR) and 3'/5' RACE from the midgut. SeCHSB contains an open reading frame of 4572 nucleotides, encoding a protein of 1523 amino acids with a predicted molecular mass of approximately 174.6 kDa. Alignment of SeCHSB with class B CHSs of other insects showed a high degree of conservation in the putative catalytic domain region. The structure of the SeCHSB gene was analyzed and was found to be the same as that of Manduca sexta CHSB (MsCHSB), including 23 exons and 22 introns but without alternative exons. Southern blot analysis revealed that SeCHSB was a single copy gene and the presence of only two chitin synthase genes in S. exigua. Further investigation indicated that SeCHSB was specifically expressed in the midgut, and its transcript existed constitutively in the midgut from the 3rd instar larval stage to prepupae and reached highest expression on the 1st day of the fifth instar larval stage. These data suggest that SeCHSB is very important in midgut formation and development. Chitin synthase gene comparisons between different classes of insects using software tools revealed some interesting aspects of the similarity and divergence of the gene in the Class Insecta.
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Quitina Sintasa/genética , Regulación Enzimológica de la Expresión Génica , Spodoptera/enzimología , Spodoptera/genética , Animales , Northern Blotting , Southern Blotting , Quitina Sintasa/química , Quitina Sintasa/metabolismo , Clonación Molecular , ADN Complementario/genética , Exones/genética , Perfilación de la Expresión Génica , Regulación del Desarrollo de la Expresión Génica , Intrones/genética , Datos de Secuencia Molecular , Filogenia , Estructura Terciaria de Proteína , ARN Mensajero/genética , ARN Mensajero/metabolismo , Análisis de Secuencia de ADNRESUMEN
The integrated pest management (IPM) strategy was developed and used in combination with pesticides and beneficial biological control agents. To further develop IPM efficiency, it is important to evaluate the side effects of pesticides on biological control agents. Aphidius gifuensis is one of the most important aphid natural enemies and has been successfully used to control Myzys persicae and other aphid species. Imidacloprid (IMD) is a popular pesticide used worldwide and is highly toxic to non-target arthropods. Here, we investigated the short-term sublethal toxicity of IMD in Aphidius gifuensis and its impact on the biological performance and gene expression of this parasitoid. We found that sublethal IMD doses had a significant negative effect on the life history traits of female A. gifuensis, including shortening the lifespan and lowering parasitic capacity. Moreover, exposure to sublethal IMD also adversely affected the response of A. gifuensis to aphid-infested plant volatiles. Based on the transcriptome analysis, we found that the exposure to sublethal IMD doses significantly affected expression of genes involved in the central nervous system, energy metabolism, olfactory, and detoxification system of A. gifuensis. RT-qPCR also revealed that short term expose to sublethal IMD doses significantly induced the gene expression of genes related to the central nervous system (nAChRa7, nAChRa9, TbH, OAR1, NFR, TYR, and DAR1), olfactory system (OR28 and IR8a1), and detoxification system (CYP49p3, CYP6a2, and POD), while it suppressed the expression of genes involved in the central nervous system (nAChRa4 and nAChRb1), olfactory system (Orco1, IR8a2, and GR1), and detoxification system (GST2). Furthermore, exposure to sublethal doses of IMD also significantly increased the activities of CarEs and POD, whereas we observed no influence on the activities of CAT, GST, and SOD. Our results indicate that sublethal IMD doses might adversely affect the biological performance of A. gifuensis by altering gene expression related to the function of olfactory, nervous, energy metabolism, and detoxification systems. Thus, how the use of pesticides directly affect insect population should be considered when used in conjunction with natural pest parasitoids in IPM strategies.
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In nature, plants have evolved sophisticated defense mechanisms against the attack of pathogens and insect herbivores. Plant volatile-mediated plant-to-plant communication has been assessed in multitrophic systems in different plant species and different pest species. ß-ocimene is recognized as an herbivore-induced plant volatile that play an important role in the chemical communication between plants and pests. However, it is still unclear whether ß-ocimene can active the defense mechanism of Chinese cabbage Brassica pekinensis against the peach aphid Myzus persicae. In this study, we found that treatment of Chinese cabbage with ß-ocimene inhibited the growth of M. persicae in terms of weight gain and reproduction. Moreover, ß-ocimene treatment negatively influenced the feeding behavior of M. persicae by shortening the total feeding period and phloem ingestion and increasing the frequency of stylet puncture. When given a choice, winged aphids preferred to settle on healthy Chinese cabbage compared with ß-ocimene-treated plants. In addition, performance of the parasitoid Aphidius gifuensis in terms of Y-tube olfaction and landings was better on ß-ocimene-treated Chinese cabbage than on healthy plants. Furthermore, ß-ocimene significantly increased the expression levels of salicylic acid and jasmonic acid marker genes and the accumulation of glucosinolates. Surprisingly, the transcriptional levels of detoxifying enzymes (CYP6CY3, CYP4, and GST) in aphids reared on ß-ocimene-treated Chinese cabbage were significantly higher than those of aphids reared on healthy plants. In summary, our results indicated that ß-ocimene can activate the defense response of Chinese cabbage against M. persicae, and that M. persicae can also adjust its detoxifying enzymes machinery to counter the host plant defense reaction.
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In natural ecological systems, plants are often simultaneously attacked by both insects and pathogens, which can affect each other's performance and the interactions can be extended to higher trophic levels, such as parasitoids. The English grain aphid (Sitobion avenae) and powdery mildew (Blumeria graminis f. sp. tritici) are two common antagonists that pose a serious threat to wheat production. Numerous studies have investigated the effect of a single factor (insect or pathogen) on wheat production. However, investigation on the interactions among insect pests, pathogens, and parasitoids within the wheat crop system are rare. Furthermore, the influence of the fungicide, propiconazole, has been found to imitate the natural ecosystem. Therefore, this study investigated the effects of B. graminis on the biological performance of grain aphids and the orientation behavior of its endoparasitic wasp Aphidius gifuensis in the wheat system. Our findings indicated that B. graminis infection suppressed the feeding behavior, adult and nymph weight, and fecundity and prolonged the developmental time of S. avenae. We found that wheat host plants had decreased proportions of essential amino acids and higher content of sucrose following aggravated B. graminis infection. The contents of Pro and Gln increased in the wheat plant tissues after B. graminis infection. In addition, B. graminis infection elicited immune responses in wheat: increase in the expression of defense genes, content of total phenolic compounds, and activity of three related antioxidant enzymes. Moreover, co-infection of B. graminis and S. avenae increased the attraction to A. gifuensis compare to that after infestation with aphids alone. In conclusion, our results indicated that B. graminis infection adversely affected the performance of S. avenae in wheat through restricted nutrition and induced defense response. Furthermore, the preference of parasitoids in such an interactive environment might provide an important basis for pest management control.
RESUMEN
BACKGROUND: Some Chinese patients with esophageal squamous cell carcinomaare often treated with single-agent concurrent chemoradiotherapy. However, no results have been reported from randomized controlled clinical trials comparing single-agent with double-agent concurrent chemoradiotherapy. It therefore remains unclear whether these regimens are equally clinically effective. In this study, we retrospectively analyzed and compared the therapeutic effects of single-agent and double-agent concurrent chemoradiotherapy in patients with unresectable esophageal squamous cell carcinoma. METHODS: This study enrolled 168 patients who received definitive concurrent chemoradiotherapy for locally advanced unresectable esophageal squamous carcinoma at 10 hospitals between 2010 and 2015. We evaluated survival time and toxicity. The Kaplan-Meier method was used to estimate survival data. The log-rank test was used in univariate analysis A Cox proportional hazards regression model was used to conduct a multivariate analysis of the effects of prognostic factors on survival. RESULTS: In this study, 100 (59.5%) and 68 patients (40.5%) received single-agent and dual-agent combination chemoradiotherapy, respectively. The estimate 5-year progression-free survival (PFS) rate and overall survival (OS) rate of dual-agent therapy was higher than that of single-agent therapy (52.5% and 40.9%, 78.2% and 60.7%, respectively), but there were no significant differences (P = 0.367 and 0.161, respectively). Multivariate analysis showed that sex, age,and radiotherapy dose had no significant effects on OS or PFS. Only disease stage was associated with OS and PFS in the multivariable analysis (P = 0.006 and 0.003, respectively). In dual-agent group, the incidence of acute toxicity and the incidence of 3 and4 grade toxicity were higher than single-agent group. CONCLUSION: The 5-year PFS and OS rates of dual-agent therapy were higher than those of single-agent concurrent chemoradiotherapy for patients with unresectable esophageal squamous cell carcinoma; however, there were no significant differences in univariate analysis and multivariable analysis. Single-agent concurrent chemotherapy had less toxicity than a double-drug regimen. Therefore, we suggest that single therapis not inferior to dual therapy y. In the future, we aim to confirm our hypothesis through a prospective randomized study.
Asunto(s)
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Carcinoma de Células Escamosas/tratamiento farmacológico , Carcinoma de Células Escamosas/radioterapia , Quimioradioterapia/métodos , Neoplasias Esofágicas/tratamiento farmacológico , Neoplasias Esofágicas/radioterapia , Adulto , Anciano , Anciano de 80 o más Años , Carcinoma de Células Escamosas/mortalidad , China , Supervivencia sin Enfermedad , Neoplasias Esofágicas/mortalidad , Carcinoma de Células Escamosas de Esófago , Femenino , Humanos , Estimación de Kaplan-Meier , Masculino , Persona de Mediana Edad , Modelos de Riesgos Proporcionales , Estudios Retrospectivos , Resultado del TratamientoRESUMEN
The green peach aphid, Myzus persicae Sulzer (Hemiptera, Aphididae), is an important cosmopolitan pest. Real time qRT-PCR has been used for target gene expression analysis on M. persicae. Using real time qRT-PCR, the expression levels are normalized on the basis of the reliable reference genes. However, to date, the stability of available reference genes has been insufficient. In this study, we evaluated nine candidate reference genes from M. persicae under diverse experimental conditions. The tested candidate genes were comprehensively ranked based on five alternative methods (RefFinder, geNorm, Normfinder, BestKeeper and the comparative ΔCt method). 18s, Actin and ribosomal protein L27 (L27) were recommended as the most stable reference genes for M. persicae, whereas ribosomal protein L27 (L27) was found to be the least stable reference genes for abiotic studies (photoperiod, temperature and insecticide susceptibility). Our finding not only sheds light on establishing an accurate and reliable normalization of real time qRT-PCR data in M. persicae but also lays a solid foundation for further studies of M. persicae involving RNA interference and functional gene research.