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138 result(s) for "Yan, Weiyu"
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Engineered chimeric insecticidal crystalline protein improves resistance to lepidopteran insects in rice (Oryza sativa L.) and maize (Zea mays L.)
The insecticidal crystalline proteins (Crys) are a family of insect endotoxin functioning in crop protection. As insects keep evolving into tolerance to the existing Crys, it is necessary to discover new Cry proteins to overcome potential threatens. Crys possess three functional domains at their N-termini, and the most active region throughout evolution was found at the domain-III. We swapped domain-IIIs from various Cry proteins and generated seven chimeric proteins. All recombinants were expressed in Escherichia coli and their toxicity was assessed by dietary exposure assays. Three of the seven Crys exhibited a high toxicity to Asian corn borer over the controls. One of them, Cry1Ab-Gc, a chimeric Cry1Ab being replaced with the domain-III of Cry1Gc, showed the highest toxicity to rice stem borer when it was over-expressed in Oryza sativa . Furthermore, it was also transformed into maize, backcrossed into commercial maize inbred lines and then produced hybrid to evaluate their commercial value. Transgenic maize performed significant resistance to the Asian corn borer without affecting the yield. We further showed that this new protein did not have adverse effects on the environment. Our results indicated that domain III swapped of Crys could be used as an efficient method for developing new engineered insecticidal protein.
Honey bee maternal effects improve worker performance and reproductive ability in offspring
Maternal effects are an evolutionary strategy used to improve offspring quality. In an example of maternal effects in honey bees ( Apis mellifera ), mother queens produce larger eggs in queen cells than in worker cells in order to breed better daughter queens. In our current study, morphological indexes, reproductive tissues, and the egg-laying ability of newly reared queens reared with eggs laid in queen cells (QE), eggs laid in worker cells (WE), and 2-day-old larvae in worker cells (2L) were evaluated. In addition, morphological indexes of offspring queens and working performance of offspring workers were examined. The thorax weight, number of ovarioles, egg length, and number of laid eggs and capped broods of QE were significantly higher than those of WE and 2L, indicating that the reproductive capacity of QE group was better than that of other groups. Furthermore, offspring queens from QE had larger thorax weights and sizes than those from the other two groups. Offspring worker bees from QE also had larger body sizes and greater pollen-collecting and royal jelly-producing abilities than those of other two groups. These results demonstrate that honey bees display profound maternal effects on queen quality that can be transmitted across generations. These findings provide a basis for improving queen quality, with implications in apicultural and agricultural production.
High-Quality Queens Produce High-Quality Offspring Queens
Honey bees, rather than rear queens with eggs and larvae from worker cells, prefer to rear new queens with eggs form queen cells, if available. This may be a result of long-term evolutionary process for honey bee colonies. However, the exact mechanism of this phenomenon is unclear. In this study, queens were reared with eggs from queen cells (F1-QE), eggs from worker cells (F1-WE), and two-day-old larvae from worker cells (F1-2L). Physiological indexes and the expression of the development-related genes ((Hexamerin (Hex110, Hex70b), Transferrin (Trf), and Vitellogenin (Vg)) of reared F1 generation queens were measured and compared. Furthermore, F2 generation queens were reared with one-day-old larvae from F1 queens, and the weight and ovariole count of reared F2 generation daughter queens were examined. Meanwhile, the expression of the development- and reproduction-related genes (Hex110, Hex70b, Trf, Vg, and Juvenile Hormone (Jh)) and immune detoxication-related genes (Hymenoptaecin, Abeacin, and CytP450) of reared F2 queens were further explored. We found that the F1-QE queens had the highest physiological indexes and higher Hex110 and Trf expression levels, while no significant difference was found in the expression of Hex70b and Vg among the three groups of F1 queens. In addition, the reared queens of F2-QE had the highest quality, with the highest development, reproduction, immune-detoxication genes’ expression levels. Our results revealed that the quality of reared offspring queens from high-quality mother queens was also high. These findings inform methods for rearing high-quality queens and highlight that a high-quality queen is essential for offspring colony growth and survival.
Knockout of a single Pax6 gene (toy but not ey) leads to compound eye deficiency and small head in honeybees
The compound eyes are crucial to honeybees, playing pivotal roles in color recognition, orientation, localization, and navigation processes. The development of compound eyes is primarily mastered by an evolutionarily conserved transcription factor Pax6. In honeybees, there are two Pax6 homologs: ey and toy . To gain a deeper understanding of their functions, we knock out both homologs using CRISPR/Cas9 technology. Intriguingly, we observe that toy knockout mutants have smaller heads without compound eyes and exhibit brain atrophy, while ey knockout mutants develop normal compound eyes, most of which die before/during their metamorphosis from pupa to adult. By comparing the head transcriptomes of four stages (larva, prepupa, pupa, and adult) in toy -knockout mutants versus normal controls, we identify significantly perturbed genes related to DNA binding transcription factors, neuron differentiation, and insect visual primordium development. Additionally, we find the interaction network of toy in honeybees differs obviously from that of D. melanogaster . Our findings suggest the two Pax6 genes serve distinct functions in honeybees and toy takes over the central function of ey in master-regulating the development of honeybee compound eyes. This adds new evidence for breaking the simplified view that some of conservative developmental toolkit genes function as all-or-nothing master regulators. Knockout of toy using CRISPR/Cas9 technology leads to small-headed honeybees without compound eyes, while ey-knockout bees have normal compound eyes, suggesting toy takes over the central role of ey in mastering honeybee compound-eye development.
Whole-Genome Resequencing−Based Qualitative Trait Locus Mapping Correlated yellow with the Mutant Color in Honeybees, Apis cerana cerana
The honeybee, Apis cerana cerana (Ac), is an important pollinator and has adapted to the local ecological environment with relevant coloration. The cuticle coloration of the brown (br) mutant is brown instead of black in wild−type individuals. Therefore, this study aimed to identify and characterize the gene responsible for the br mutation. Genome resequencing with allele segregation measurement using Euclidean distance followed by Lowess regression analysis revealed that the color locus linked to the mutation was located on chromosome 11. A 2−base deletion on exon 4 was identified in the g7628 (yellow) gene after genome assembly and sequence cloning. In addition, the cuticle color of the abdomen of worker bees changed from black to brown when a defect was induced in the yellow gene using short interfering RNA (siRNA); however, the survival rate did not decrease significantly. These results indicate that the yellow gene participated in the body pigmentation, and its defect was responsible for the br mutation. This study promotes the understanding of the molecular basis of body coloration in honeybees, enriching the molecular mechanisms underlying insect pigmentation.
Uptake of quercetin reduces larval sensitivity to lambda-cyhalothrin in Helicoverpa armigera
Quercetin, one of the most abundant dietary flavonoids, is widely present in nature. In this study, the effects of quercetin ingestion on Helicoverpa armigera larvae growth and its sensitivity to lambda-cyhalothrin were assessed. The median lethal concentration (LC50) value of lambda-cyhalothrin to quercetin-fed H. armigera larvae was 2.39-fold higher than the control, suggesting a reduced sensitivity to lambda-cyhalothrin. Piperonyl butoxide (PBO) treatment effectively synergized lambda-cyhalothrin efficacy in quercetin-fed H. armigera larvae with a synergistic ratio of 2.36. Moreover, the growth of H. armigera larvae was inhibited by the quercetin uptake. To understand the reduced sensitivity to lambda-cyhalothrin, we measured the enzymatic activity of cytochrome P450 monooxygenases (P450s), as well as transcriptional responses of three P450s genes in quercetin-fed H. armigera larvae. We found that cytochrome P450 monooxygenases involved in the observed lambda-cyhalothrin tolerance in quercetin-fed H. armigera. After fed on quercetin for 48 h, 7-ethoxycoumarin-O-deethylase (ECOD) activity was significantly elevated in quercetin-fed H. armigera larvae; meanwhile, the expression level of CYP6B6, CYP6B8 and CYP321A1 was up-regulated. In conclusion, P450s played a crucial role in the metabolic adaptation of H. armigera larvae to its host plant's secondary metabolites as well as synthetic insecticides. The reduced lambda-cyhalothrin sensitivity in quercetin-fed H. armigera larvae suggested that previous exposure to the host plant-derived quercetin is likely to compromise the efficacy of pyrethroid insecticides.
Assessment of macular function in patients with idiopathic Epiretinal membrane by multifocal Electroretinography: correlation with visual acuity and optical coherence tomography
Background This study evaluates the macular function changes in patients with idiopathic macular epiretinal membrane (ERM) by multifocal electroretinography (mfERG) and their correlations with visual acuity and central macular thickness (CMT) by optical coherence tomography (OCT). Methods Twenty eyes of 20 patients with ERM underwent OCT and mfERG examinations. The response amplitude densities and implicit times of mfERG were compared to the control fellow eyes. Correlation analyses among visual acuity, central macular thickness and mfERG values in the central two concentric rings were performed. Results The mfERG P1 response amplitude densities in ring 1–2 and P1 implicit time in ring1 were significantly changed in epiretinal membrane eyes compared with controls ( P < 0.05 ). Multivariate stepwise linear regression analyses showed LogMAR visual acuity was significantly correlated with CMT ( P = 0.004 ), and also with the P1 amplitude density in ring 1 ( P = 0.002 ). CMT showed significant correlation with P1 implicit time in ring 2 ( P = 0.013 ). Conclusions The mfERG abnormalities show macular function changes and correlate with visual acuity and central macular thickness in eyes with ERM. In first-order mfERG responses, P1 wave changes may be a sensitive functional measurement for ERM patients.
Phenotype-Based Genetic Analysis Reveals Missing Heritability of KIF11-Related Retinopathy: Clinical and Genetic Findings
The purpose of this study was to detect the missing heritability of patients with KIF11-related retinopathy and to describe their clinical and genetic characteristics. We enrolled 10 individuals from 7 unrelated families harboring a pathogenic monoallelic variant in KIF11. All subjects underwent ophthalmic assessment and extraocular phenotype evaluations, as well as comprehensive molecular genetic analyses using next-generation sequencing. Minigene assays were performed to observe the effects of one novel deep intron variant (DIV) and one novel synonymous variant on pre-mRNA splicing. We detected 6 novel different disease-causing variants of KIF11 in the seven pedigrees. Co-segregation analysis and ultra-deep sequencing results indicated that 5 variants arose de novo in 5 families (71%). Functional validation revealed that the synonymous variant leads to an exon skip, while the DIV causes a pseudoexon (PE) inclusion. The patients presented with high variations in their phenotype, and two families exhibited incomplete penetrance. Ocular manifestations and characteristic facial features were observed in all patients, as well as microcephaly in seven patients, intellectual disability in five patients, and lymphedema in one patient. The key retinal features for KIF11-related retinopathy were retinal folds, tractional retinal detachment, and chorioretinal dysplasia. All seven probands had more severe visual detects than other affected family members. Our findings widen the genetic spectrum of KIF11 variants. DIV explained rare unresolved cases with KIF11-related retinopathy. The patients displayed a variable phenotype expressivity and incomplete penetrance, indicating the importance of genetic analysis for patients with KIF11-related retinopathy.
Whole-Genome Resequencing−Based Qualitative Trait Locus Mapping Correlated Iyellow/I with the Mutant Color in Honeybees, IApis cerana cerana/I
This study examined the genetic basis of a mutation in cuticle color in the honeybee Apis cerana cerana using genome resequencing of wild−type and mutant drones produced by a single virgin queen. A candidate locus was identified by calculating the Euclidean distance between mutants and wild types at each SNP, performing Lowess regression to fit a curve to these data, and setting a threshold of the top 0.5% Euclidean distance for candidate region selection. From this, genes with synonymous substitutions became candidate genes. One of these genes, the yellow gene, had a 2 bp deletion causing a frameshift mutation. RT−qPCR of this gene was performed on RNA extracted from mutant and wild−type drones; gene expression was only significantly different between wild types and mutants at the yellow gene. Finally, RNA interference silencing of the yellow gene was used to reduce yellow gene expression in workers and putatively result in a lighter coloration. These results indicate that the yellow gene participated in the body pigmentation, and its defect was responsible for the brown mutation. It promotes the understanding of the molecular basis of body coloration in honeybees, enriching the molecular mechanisms underlying insect pigmentation. The honeybee, Apis cerana cerana (Ac), is an important pollinator and has adapted to the local ecological environment with relevant coloration. The cuticle coloration of the brown (br) mutant is brown instead of black in wild−type individuals. Therefore, this study aimed to identify and characterize the gene responsible for the br mutation. Genome resequencing with allele segregation measurement using Euclidean distance followed by Lowess regression analysis revealed that the color locus linked to the mutation was located on chromosome 11. A 2−base deletion on exon 4 was identified in the g7628 (yellow) gene after genome assembly and sequence cloning. In addition, the cuticle color of the abdomen of worker bees changed from black to brown when a defect was induced in the yellow gene using short interfering RNA (siRNA); however, the survival rate did not decrease significantly. These results indicate that the yellow gene participated in the body pigmentation, and its defect was responsible for the br mutation. This study promotes the understanding of the molecular basis of body coloration in honeybees, enriching the molecular mechanisms underlying insect pigmentation.