Clinical value of auditory nerve enhancement in idiopathic sudden sensorineural hearing loss: a retrospective study.

Background: The pathogenesis of idiopathic sudden sensorineural hearing loss remains unclear, and no substantial breakthroughs have been achieved in its treatment. Therefore, we conducted this study with the aim to investigate the clinical features and prognostic factors of patients with idiopathic sudden sensorineural hearing loss and auditory nerve enhancement by using three-dimensional fluid-attenuated inversion recovery (3D-FLAIR) magnetic resonance imaging (MRI) of the inner ear. Methods: We retrospectively analyzed the clinical data of adult patients, who experienced sudden unilateral deafness and were admitted to the Department of Otolaryngology, Shandong Provincial ENT Hospital, between December 2020 and July 2021. Patients were divided into an auditory nerve enhancement group and a normal inner ear group, according to 3D-FLAIR MRI findings. Differences in sex, age, side, disease course, underlying diseases, dizziness/vertigo, vestibular function, degree of deafness, hearing classification, and treatment efficacy were analyzed. Results: Of the 112 cases of sudden idiopathic deafness, 16.07% exhibited enhancement of the auditory nerve on inner-ear 3D-FLAIR MRI. Statistically significant differences in the degree and type of hearing loss were detected between the two groups (p < 0.05). The rates of abnormal results in the caloric, vestibular-evoked myogenic potential, and video head impulse tests were higher in the auditory nerve enhancement group. The cure rate (11.1%) in patients with auditory nerve enhancement was lower than that in patients with normal inner ear MRI findings (28.7%); however, the difference was not statistically significant. Conclusion: Findings from 3D-FLAIR MRI scans of the inner ear indicated that patients with sudden deafness and auditory nerve enhancement experienced severe hearing loss, aggravated vestibular function injury, and a significantly decreased cure rate. Prompt treatment, ideally within 2 weeks of disease onset, can facilitate hearing recovery.

The BTB-ZF gene Bm-mamo regulates pigmentation in silkworm caterpillars.

The color pattern of insects is one of the most diverse adaptive evolutionary phenotypes. However, the molecular regulation of this color pattern is not fully understood. In this study, we found that the transcription factor Bm-mamo is responsible for black dilute (bd) allele mutations in the silkworm. Bm-mamo belongs to the BTB zinc finger family and is orthologous to mamo in Drosophila melanogaster. This gene has a conserved function in gamete production in Drosophila and silkworms and has evolved a pleiotropic function in the regulation of color patterns in caterpillars. Using RNAi and clustered regularly interspaced short palindromic repeats (CRISPR) technology, we showed that Bm-mamo is a repressor of dark melanin patterns in the larval epidermis. Using in vitro binding assays and gene expression profiling in wild-type and mutant larvae, we also showed that Bm-mamo likely regulates the expression of related pigment synthesis and cuticular protein genes in a coordinated manner to mediate its role in color pattern formation. This mechanism is consistent with the dual role of this transcription factor in regulating both the structure and shape of the cuticle and the pigments that are embedded within it. This study provides new insight into the regulation of color patterns as well as into the construction of more complex epidermal features in some insects.

INOS ablation promotes corneal wound healing via activation of Akt signaling.

Corneal injury leads to impaired normal structure of the cornea. Improving the wound healing process in epithelial cells significantly contributes to ocular damage treatments. Here, we aimed to investigate the potential mechanisms of nitric oxide (NO) and its mediator, inducible nitric oxide synthase (iNOS), in the process of corneal wound healing. We established a corneal injury model of iNOS-/- mice, and treated human corneal epithelial cell lines (HCE-2) with the iNOS inhibitor L-INL, with or without NO replenishment by supplying sodium nitroferricyanide dihydrate (SNP). Our findings showed that inhibition of NO/iNOS accelerated corneal repair, enhanced uPAR (a receptor protein indicating the migration ability), and improved epithelial cell migration. Furthermore, NO/iNOS ablation activated Akt phosphorylation, reduced neutrophil marker protein MPO expression, and downregulated the transcription of inflammation cytokines CXCL-1, CXCL-2, IL-1ß, IL-6, and TNF-α. However, the protective effects of NO/iNOS inhibition are significantly reduced by NO replenishment when treated with SNP. Therefore, we confirmed that inhibiting NO/iNOS improved the corneal wound healing by facilitating epithelial cell migration and reducing inflammatory reactions, which might be related to the activation of the Akt signaling pathway.

Super silkworm cocoons constructed by multi-silkworm larvae: Promising composites with dense structures and excellent mechanical properties.

A normal silkworm cocoon (NSC) with a unique nonwoven structure is usually spun by a single silkworm larva. Notably, there is a special Bombyx mori genetic resource that many (three or more) mature larvae tend to collectively spin into one cocoon, which was named "multi-silkworm cocoon" ("MSC"). However, the MSCs display loose structure and poor mechanical properties which limits their further application. In this study, a series of hybrid silkworm cocoons (HMSCs) are obtained by hybridizing "MSC" with a selected commercial silkworm strain successfully. The morphology, microstructures, and mechanical properties of cocoons constructed by one to three silkworm larvae were characterized and compared. The results indicated that about 48.3 % of silkworm larvae could create double and triple cocoons in the F1 generation of the silkworm hybrid, displaying robust fiber networks and dense structures. The mechanical characteristics of the HMSCs, including the tensile, peeling, compression, and needle penetration resistance properties, exceeded those of MSCs, showing significant application potential for high-performance bio-composites. This study provides a practical approach for obtaining silkworm cocoons with controllable structures and mechanical properties to develop and fabricate natural composite and biomimetic materials.

SilkMeta: a comprehensive platform for sharing and exploiting pan-genomic and multi-omic silkworm data.

The silkworm Bombyx mori is a domesticated insect that serves as an animal model for research and agriculture. The silkworm super-pan-genome dataset, which we published last year, is a unique resource for the study of global genomic diversity and phenotype-genotype association. Here we present SilkMeta (http://silkmeta.org.cn), a comprehensive database covering the available silkworm pan-genome and multi-omics data. The database contains 1082 short-read genomes, 546 long-read assembled genomes, 1168 transcriptomes, 294 phenotype characterizations (phenome), tens of millions of variations (variome), 7253 long non-coding RNAs (lncRNAs), 18 717 full length transcripts and a set of population statistics. We have compiled publications on functional genomics research and genetic stock deciphering (mutant map). A range of bioinformatics tools is also provided for data visualization and retrieval. The large batch of omics data and tools were integrated in twelve functional modules that provide useful strategies and data for comparative and functional genomics research. The interactive bioinformatics platform SilkMeta will benefit not only the silkworm but also the insect biology communities.

Study on Failure Mechanism and Numerical Simulation of Argillaceous Slate in Southeastern Guizhou.

The content of quartz and clay minerals has a crucial influence on the mechanical properties of slate, which is manifested by the differences in microscopic displacement and energy conversion during uniaxial compression. With Qiandongnan argillaceous slate in Guizhou Province as the research object, the parameters for numerical simulation were determined through indoor uniaxial tests, and argillaceous slate models with different mineral contents were established to analyze crack formation and energy conversion during uniaxial compression. The damage rate of the specimen was qualitatively analyzed by the fractal dimension of the crack. The results show that ① the number of fractures increases with the increase of quartz content, and the number of cracks in Group 4 is 33.4% higher than that in Group 1, and macroscopic fractures are dominated by cracks while microscopic fractures by tension fractures, accompanied by a small amount of shear; ② the energy change curves of the four groups of specimens are consistent with the stress-strain curves, which are divided into three stages, namely elastic deformation, yield, and strength loss. The strain energy in the strength loss stage is negatively correlated with the dissipated energy, and the dissipated energy of the four groups of specimens is positively correlated with the content of quartz; ③ the damage rates for the specimens in Groups 1 to 4 quantitatively analyzed using fracture fractal dimension are 56.8, 59.1, 65.8, and 70.7%, respectively. The research results obtained in this article have further improved the failure mechanism of argillaceous slate under uniaxial compression.

Impact of environmental noise exposure as an inducing factor on the prognosis of sudden sensorineural hearing loss: a retrospective case-control study.

Objective: The study aimed to evaluate the clinical characteristics and prognostic factors associated with unilateral sudden sensorineural hearing loss (SSNHL) related to environmental noise exposure before its onset. Methods: A total of 50 unilateral SSNHL patients exposed to environmental noise before onset (case group) and 924 unilateral SSNHL patients without any exposure to obvious inducing factors before onset (control group) were enrolled between January 2018 and October 2022. We retrospectively analyzed differences between both groups using the chi-square test, Fisher's exact tests, independent t-tests, and Mann-Whitney U-tests as appropriate before and after propensity score matching (PSM) based on sex, age, and initial pure-tone average (PTA). Prognostic factors for the case group were analyzed using univariate and multivariate logistic analyses between the effective and ineffective groups. Results: Before PSM, significant differences were noted in age, sex, time to treatment, the proportion of combined diabetes mellitus, initial PTA, hearing gain, the incidence of vertigo or aural fulness, the rate of vestibular dysfunction or inner ear MRI abnormalities, the effective rate, the glucose and homocysteine levels, and the proportion of audiogram curve types (P < 0.05) between both groups. After PSM, compared to the control group, a longer time to treatment (Z= -3.02, P < 0.05), higher final PTA (Z= -2.39, P < 0.05), lower hearing gain (Z= -3.46, P < 0.05), lower rate of vestibular dysfunction (χ2 = 55.1, P < 0.001), and lower effective rate (χ2 = 4.87, P < 0.05) were observed in the case group. There was a significant difference between the audiogram curve types in both groups (χ2 = 14.9, P < 0.05). Time to treatment (95% confidence interval: 0.692-0.965, P < 0.05) and final PTA (95% confidence interval: 0.921-0.998, P < 0.05) were associated with the clinical outcomes for the case group. Conclusion: Unilateral SSNHL patients exposed to environmental noise triggers before onset showed a poorer effective rate and a lower rate of vestibular dysfunction than those who were not. The time to treatment and final PTA were associated with the prognosis of these patients.

Characteristics and prognostic analysis of simultaneous bilateral sudden sensorineural hearing loss.

Objective: To evaluate the clinical characteristics of simultaneous bilateral sudden sensorineural hearing loss (Si-BSSNHL) as well as its prognostic factors. Methods: Patients with Si-BSSNHL who were admitted to the Department of Otology Medicine between December 2018 and December 2021 were enrolled in the case group. Propensity score matching (PSM) for sex and age was used to select the control group, which included people who had unilateral sudden sensorineural hearing loss (USSNHL) during the same time period. Hearing recovery, audiological examinations, vestibular function assessments, laboratory tests, and demographic and clinical manifestations were analyzed for intergroup comparisons. Binary logistic regressions were used for both univariate and multivariate analyses of Si-BSSNHL prognostic factors. Results: Before PSM, the Si-BSSNHL and USSNHL groups differed significantly (p < 0.05) in terms of time from onset to treatment, initial pure-tone average (PTA), final PTA, hearing gain, audiogram curve type, proportion of tinnitus, high-density lipoprotein level, homocysteine level, and effective rate. After PSM, significant differences were also observed in time from onset to treatment, initial PTA, final PTA, hearing gain, total and indirect bilirubin levels, homocysteine level, and effective rate between the two groups (p < 0.05). There was a significant difference in the classification of therapeutic effects between the two groups (p < 0.001). For prognostic analysis, the audiogram curve type was significantly different between the effective group and the ineffective groups of Si-BSSNHL (p = 0.01), in which the sloping type was an independent risk factor for the prognosis of the right ear in Si-SSNHL (95% confidence interval, 0.006-0.549, p = 0.013). Conclusion: Patients with Si-BSSNHL had mild deafness, elevated total and indirect bilirubin and homocysteine levels, and poorer prognosis than those with USSNHL. Audiogram curve type was linked to the therapeutic effect of Si-BSSNHL, and the sloping type was an independent risk factor for a poor prognosis in the right ear of Si-SSNHL.

Mutation Rate and Spectrum of the Silkworm in Normal and Temperature Stress Conditions.

Mutation rate is a crucial parameter in evolutionary genetics. However, the mutation rate of most species as well as the extent to which the environment can alter the genome of multicellular organisms remain poorly understood. Here, we used parents-progeny sequencing to investigate the mutation rate and spectrum of the domestic silkworm (Bombyx mori) among normal and two temperature stress conditions (32 °C and 0 °C). The rate of single-nucleotide mutations in the normal temperature rearing condition was 0.41 × 10-8 (95% confidence interval, 0.33 × 10-8-0.49 × 10-8) per site per generation, which was up to 1.5-fold higher than in four previously studied insects. Moreover, the mutation rates of the silkworm under the stresses are significantly higher than in normal conditions. Furthermore, the mutation rate varies less in gene regions under normal and temperature stresses. Together, these findings expand the known diversity of the mutation rate among eukaryotes but also have implications for evolutionary analysis that assumes a constant mutation rate among species and environments.

Deciphering the Genetic Basis of Silkworm Cocoon Colors Provides New Insights into Biological Coloration and Phenotypic Diversification.

The genetic basis of phenotypic variation is a long-standing concern of evolutionary biology. Coloration has proven to be a visual, easily quantifiable, and highly tractable system for genetic analysis and is an ever-evolving focus of biological research. Compared with the homogenized brown-yellow cocoons of wild silkworms, the cocoons of domestic silkworms are spectacularly diverse in color, such as white, green, and yellow-red; this provides an outstanding model for exploring the phenotypic diversification and biological coloration. Herein, the molecular mechanism underlying silkworm green cocoon formation was investigated, which was not fully understood. We demonstrated that five of the seven members of a sugar transporter gene cluster were specifically duplicated in the Bombycidae and evolved new spatial expression patterns predominantly expressed in silk glands, accompanying complementary temporal expression; they synergistically facilitate the uptake of flavonoids, thus determining the green cocoon. Subsequently, polymorphic cocoon coloring landscape involving multiple loci and the evolution of cocoon color from wild to domestic silkworms were analyzed based on the pan-genome sequencing data. It was found that cocoon coloration involved epistatic interaction between loci; all the identified cocoon color-related loci existed in wild silkworms; the genetic segregation, recombination, and variation of these loci shaped the multicolored cocoons of domestic silkworms. This study revealed a new mechanism for flavonoids-based biological coloration that highlights the crucial role of gene duplication followed by functional diversification in acquiring new genetic functions; furthermore, the results in this work provide insight into phenotypic innovation during domestication.

The relationship between baseline axial length and axial elongation in myopic children undergoing orthokeratology.

PURPOSE: To investigate the correlation between the baseline axial length (AL) and axial elongation in myopes undergoing orthokeratology (ortho-k). METHODS: This was a retrospective study. During the 1-year follow-up, 1176 children (aged 8-14 years) were included and divided into an ortho-k group (n = 588) and a single-vision spectacle group (n = 588). The ortho-k group participants (8-11 years of age) who completed the 3-year follow-up (n = 150) were further divided into three subgroups stratified by their baseline AL: subgroup 1 (AL < 24.5 mm), subgroup 2 (24.5 ≤ AL < 26 mm) and subgroup 3 (AL ≥ 26 mm). AL was measured at baseline and during the annual visit. RESULTS: The ortho-k group exhibited slower 1-year axial elongation (39% reduction) than the spectacle group. The 1-year axial elongation was negatively correlated with initial age in both groups. A negative association between 1-year axial elongation and baseline AL was observed in the ortho-k group but not in the spectacle group. However, this relationship only existed in ortho-k participants 8-11 years of age. For the younger ortho-k participants who completed the 3-year follow-up, the annual axial elongation was significantly higher in subgroup 1 for the first and second years but not in the third year compared with subgroups 2 and 3. CONCLUSION: Axial elongation was negatively correlated with baseline AL in the ortho-k group. Children aged 8-11 years with longer baseline AL (≥24.5 mm) demonstrated slower annual axial elongation during the first 2 years of ortho-k treatment, which may provide insight into establishing individual guidelines for controlling myopia using ortho-k in children with different baseline characteristics.

Analysis of the relationship between axial length, optic disc morphology, and regional variations in retinal vessel density in young adults with healthy eyes.

Purpose: To investigate the relationship between optic disc morphology, axial length, and regional distribution of retinal vessels in healthy eyes of young adults. Methods: Nine hundred and two healthy eyes were enrolled in this university-based, cross-sectional study. Spectral-domain optical coherence tomography angiography was used to measure the parapapillary retinal vessel density. We automated the process of calculating optic disc tilt and rotation by using a program written in Python. Relationships between optic disc rotation, optic disc tilt, parapapillary vessel density, and other ocular parameters were analyzed using regression models. Results: As axial length increased, optic disc morphology became more tilted and rotated inferiorly. The superficial vessel density (SVD) and radial peripapillary capillary density (RPCD) gradually decreased in all regions except for the temporal quadrant. Increased temporal SVD (OR [95% CI] = 1.081 [1.039, 1.124], p < 0.001), reduced nasal SVD (OR [95% CI] = 0.898 [0.861, 0.937], p < 0.01), and short relative lens position (OR [95% CI] = 0.126 [0.032, 0.495], p = 0.003) were significantly associated with the presence of a tilted optic disc. Inferior disc rotation was associated with decreased superior deep vessel density (DVD) and increased inferior DVD and temporal DVD after adjusting for sex and axial length. Conclusion: The tilted and rotated optic discs were associated with the distribution of SVD and DVD, respectively. We should fully consider the influence of optic disc morphology on parapapillary vessel density in eyes with myopia.

High-resolution silkworm pan-genome provides genetic insights into artificial selection and ecological adaptation.

The silkworm Bombyx mori is an important economic insect for producing silk, the "queen of fabrics". The currently available genomes limit the understanding of its genetic diversity and the discovery of valuable alleles for breeding. Here, we deeply re-sequence 1,078 silkworms and assemble long-read genomes for 545 representatives. We construct a high-resolution pan-genome dataset representing almost the entire genomic content in the silkworm. We find that the silkworm population harbors a high density of genomic variants and identify 7308 new genes, 4260 (22%) core genes, and 3,432,266 non-redundant structure variations (SVs). We reveal hundreds of genes and SVs that may contribute to the artificial selection (domestication and breeding) of silkworm. Further, we focus on four genes responsible, respectively, for two economic (silk yield and silk fineness) and two ecologically adaptive traits (egg diapause and aposematic coloration). Taken together, our population-scale genomic resources will promote functional genomics studies and breeding improvement for silkworm.

A Blueprint of Microstructures and Stage-Specific Transcriptome Dynamics of Cuticle Formation in Bombyx mori.

Insect cuticle is critical for the environmental adaptability and insecticide resistance of insects. However, there is no clear understanding of the structure and protein components of the cuticle during each developmental stage of holometabolous insects, and knowledge about the protein components within each layer is vague. We conducted serial sectioning, cuticular structure analysis, and transcriptome sequencing of the larval, pupal, and adult cuticles of Bombyx mori. The deposition processes of epicuticle, exocuticle, and endocuticle during larval, pupal, and adult cuticle formation were similar. Transcriptome analysis showed that these cuticle formations share 74% of the expressed cuticular protein (CP) genes and 20 other structural protein genes, such as larval serum protein and prisilkin. There are seven, six, and eleven stage-specific expressed CP genes in larval, pupal, and adult cuticles, respectively. The types and levels of CP genes may be the key determinants of the properties of each cuticular layer. For example, the CPs of the RR-2 protein family with high contents of histidine (His) are more essential for the exocuticle. Functional analysis suggested that BmorCPAP1-H is involved in cuticle formation. This study not only offers an in-depth understanding of cuticle morphology and protein components but also facilitates the elucidation of molecular mechanisms underlying cuticle formation in future studies.

Idiopathic Sudden Sensorineural Hearing Loss in Different Ages: Prognosis of Patients With Initial Total Hearing Loss.

Objective: This study aimed to analyze the hearing improvement and prognosis factors of idiopathic sudden sensorineural hearing loss (ISSNHL) in different ages with initial total hearing loss. Methods: We reviewed the medical records of 5,711 hospitalized patients with ISSNHL from 2016 to 2021 in our center. All of the patients had been treated with uniform combination drug therapy. After excluding the patients with initial partial hearing loss and those diagnosed with clear etiology, 188 patients were enrolled in this study and divided into six age groups (18-30, 31-40, 41-50, 51-60, 61-70, ≥ 71 years). In all groups, decreases in pure-tone average (PTA) 1 month posttreatment, effective rate, and clinical characteristics (vertigo, tinnitus, hospital stay, comorbidity, and inner ear magnetic resonance imaging) were analyzed. Results: Among the 188 enrolled patients, 86% had vertigo. Complete recovery was seen in 0.5% of patients, and marked recovery was seen in 43% of patients. The mean 1 month posttreatment PTAs were as follows: 18-30 years: 80 ± 7.5 dB; 31-40 years: 100 ± 9.0 dB; 41-50 years: 99 ± 8.3 dB; 51-60 years: 101 ± 8.6 dB; 61-70 years: 96 ± 9.6 dB; and ≥ 71 years: 88 ± 13.0 dB. Compared with the other groups, the 18-30- years group showed better recovery of hearing threshold in five frequencies (0.25, 0.5, 1, 2, and 4 kHz, respectively, at octave or semioctave frequencies under air conduction), and the recovery of hearing threshold at 0.25 and 0.5 Hz was better than the recovery at 1, 2, and 4 kHz. According to the results of the chi-square test statistical analysis, vertigo and comorbidities were associated with a poor prognosis of ISSNHL. Conclusion: In summary, the treatment outcomes of patients with ISSNHL with initial total hearing loss were poor. There was a significant age-related difference with respect to marked recovery 1 month posttreatment, and the 18-30- years group showed better recovery than the other age groups.

The Role of Chitooligosaccharidolytic ß-N-Acetylglucosamindase in the Molting and Wing Development of the Silkworm Bombyx mori.

The insect glycoside hydrolase family 20 ß-N-acetylhexosaminidases (HEXs) are key enzymes involved in chitin degradation. In this study, nine HEX genes in Bombyx mori were identified by genome-wide analysis. Bioinformatic analysis based on the transcriptome database indicated that each gene had a distinct expression pattern. qRT-PCR was performed to detect the expression pattern of the chitooligosaccharidolytic ß-N-acetylglucosaminidase (BmChiNAG). BmChiNAG was highly expressed in chitin-rich tissues, such as the epidermis. In the wing disc and epidermis, BmChiNAG has the highest expression level during the wandering stage. CRISPR/Cas9-mediated BmChiNAG deletion was used to study the function. In the BmChiNAG-knockout line, 39.2% of female heterozygotes had small and curly wings. The ultrastructure of a cross-section showed that the lack of BmChiNAG affected the stratification of the wing membrane and the formation of the correct wing vein structure. The molting process of the homozygotes was severely hindered during the larva to pupa transition. Epidermal sections showed that the endocuticle of the pupa was not degraded in the mutant. These results indicate that BmChiNAG is involved in chitin catabolism and plays an important role in the molting and wing development of the silkworm, which highlights the potential of BmChiNAG as a pest control target.

The Landscapes of Full-Length Transcripts and Splice Isoforms as Well as Transposons Exonization in the Lepidopteran Model System, Bombyx mori.

The domesticated silkworm, Bombyx mori, is an important model system for the order Lepidoptera. Currently, based on third-generation sequencing, the chromosome-level genome of Bombyx mori has been released. However, its transcripts were mainly assembled by using short reads of second-generation sequencing and expressed sequence tags which cannot explain the transcript profile accurately. Here, we used PacBio Iso-Seq technology to investigate the transcripts from 45 developmental stages of Bombyx mori. We obtained 25,970 non-redundant high-quality consensus isoforms capturing ∼60% of previous reported RNAs, 15,431 (∼47%) novel transcripts, and identified 7,253 long non-coding RNA (lncRNA) with a large proportion of novel lncRNA (∼56%). In addition, we found that transposable elements (TEs) exonization account for 11,671 (∼45%) transcripts including 5,980 protein-coding transcripts (∼32%) and 5,691 lncRNAs (∼79%). Overall, our results expand the silkworm transcripts and have general implications to understand the interaction between TEs and their host genes. These transcripts resource will promote functional studies of genes and lncRNAs as well as TEs in the silkworm.

DIA-based proteome reveals the involvement of cuticular proteins and lipids in the wing structure construction in the silkworm.

Wing discs of Bombyx mori (B. mori) are transformed into wings during metamorphosis via dramatic morphological and structural changes. Mutations in genes related to the wings cause the adults to have altered wing shapes or abnormal wing colour. At present, there are more than 20 wing mutants recorded in the silkworm. However, the key factors that influence B. mori wing development are still unclear. Here, we used the strains +Wes/+Wes and Wes/+Wes that are typical for the normal wing and shriveled wing phenotypes, respectively, to identify differentially expressed proteins by label-free data-independent acquisition (DIA). Ten enriched GO terms and 9 KEGG pathways were identified based on the 3993 proteins in the wings. Among the identified and quantified proteins, 370 differentially expressed proteins (DEPs) were detected (P-value <0.01, |log2FC| > 0.58). Mapping of the DEPs to the reference canonical pathways in KEGG showed that the top 20% of the pathways were related to fatty acid, cutin, suberin and wax biosynthesis, protein processing in endoplasmic reticulum, protein export, etc. Of the 370 DEPs, 238 were down-regulated, and 132 were up-regulated of Wes/+Wes compared with +Wes/+Wes. Numerous cuticular proteins were down-regulated, and fatty metabolism enzymes were up-regulated, in Wes/+Wes compared with +Wes/+Wes. SIGNIFICANCE: The comparative analysis of proteomes suggested that cuticular proteins and fatty metabolism enzymes are the main abnormally expressed proteins in the pupal wings of Wes/+Wes, leading to curly and shrunken wings after moth transformation. Our results also identify the substances affecting the development of silkworm wings from the perspective of proteins. The information from this study is important for further research on the molecular mechanisms of wing development in lepidopteran insects, and these differentially expressed genes may be targets for Lepidoptera pest control.

Whole-genome resequencing reveals loci under selection during silkworm improvement.

Breeding or genetic improvement refers to the process of artificial selection following domestication; as such, it has had a major influence on modern agriculture and animal production. Improvement generally focuses on traits that greatly affect the economic performance. Therefore, understanding the genetic basis underlying improvement will contribute to the identification of genes controlling economic traits and will facilitate future crop and animal breeding. However, genome-wide study of the molecular basis underlying improvement remains rare. The silkworm is a unique, entirely domesticated economically important invertebrate; genetic improvement has had a huge effect on the silkworm regarding silk-related traits. Herein, we performed whole-genomic sequencing on local and genetically improved silkworm lines to identify the genomic regions under strong selection in silkworm breeding/improvement. By genomic-wide selective sweeping analysis, we identified 24 genomic regions with strong selection signals, eight of which contained 13 candidate genes underlying silkworm breeding. Interestingly, six of these genes were annotated with functions related to neural signal response. Among the six genes, BGIBMGA004050 encodes silkworm CREB-regulated_transcription_coactivator_1 (BmCRTC1), which was reported to be involved in energy-sensing pathways. These results suggested that improvement may have affected the nervous system of the silkworm. This research will provide new insights into the genetic basis underlying the genetic improvement of silkworms and possibly of other species.

Identification, expression, and artificial selection of silkworm epigenetic modification enzymes.

BACKGROUND: Understanding the genetic basis of phenotype variations during domestication and breeding is of great interest. Epigenetics and epigenetic modification enzymes (EMEs) may play a role in phenotypic variations; however, no comprehensive study has been performed to date. Domesticated silkworm (Bombyx mori) may be utilized as a model in determining how EMEs influence domestication traits. RESULTS: We identified 44 EMEs in the genome of silkworm (Bombyx mori) using homology searching. Phylogenetic analysis showed that genes in a subfamily among different animals were well clustered, and the expression pattern of EMEs is constant among Bombyx mori, Drosophila melanogaster, and Mus musculus. These are most highly expressed in brain, early embryo, and internal genitalia. By gene-related selective sweeping, we identified five BmEMEs under artificial selection during the domestication and breeding of silkworm. Among these selected genes, BmSuv4-20 and BmDNMT2 harbor selective mutations in their upstream regions that alter transcription factor-binding sites. Furthermore, these two genes are expressed higher in the testis and ovary of domesticated silkworm compared to wild silkworms, and correlations between their expression pattern and meiosis of the sperm and ova were observed. CONCLUSIONS: The domestication of silkworm has induced artificial selection on epigenetic modification markers that may have led to phenotypic changes during domestication. We present a novel perspective to understand the genetic basis underlying animal domestication and breeding.