More potential uses of specific perforator flaps in the calf - A cadaveric study on the subdermal vascular structure of the lower leg.

BACKGROUND: The perforator flap has garnered significant interest since its inception due to its advantage of not needing a vascular network at the deep fascial level. Perforator flaps are commonly utilized in different flap transplant surgeries, and the thigh flap is presently the most widely used perforator flap. Is it possible for the calf to replace the thigh as a more suitable site for harvesting materials? Currently, there is a lack of relevant anatomical research. This study aims to address this question from an anatomical and imaging perspective. METHODS: This study used cadavers to observe the branches and courses of perforators on the calf and the distribution of skin branches using microdissection techniques, digital X-ray photography, and micro-computed tomography techniques. RESULTS: The perforators had three main branches: the vertical cutaneous branch, the oblique cutaneous branch, and the superficial fascial branch. The superficial fascial branch traveled in the superficial fascia and connected with the nearby perforators. The vertical and oblique cutaneous branches entered the subdermal layer and connected with each other to create the subdermal vascular network. CONCLUSIONS: We observed an intact calf cutaneous branch chain between the cutaneous nerve and the perforator of the infrapopliteal main artery at the superficial vein site. Utilizing this anatomical structure, the calfskin branch has the potential to serve as a substitute for thigh skin flap transplantation and may be applied to perforator flap transplantation in more locations.

Lipid and Amino Acid Pathway Metabolites Contribute to Cold Tolerance in Quercus wutaishanica.

Cold is an important environmental stress affecting the growth, productivity, and geographic distribution of tree species. Oaks are important for environmental conservation and wood supplies. Oak metabolites respond to low temperatures (LTs). In this study, the physiological and metabolic responses of two oak species to cold stress were investigated and compared. The field observations and physiological responses showed that Quercus wutaishanica was more cold-tolerant than Q. acutissima. After frost, the one-year-old twigs of Q. wutaishanica had higher survival rates, accumulated more soluble sugar and protein, and exhibited higher superoxide dismutase (SOD) activity than those of Q. acutissima. Untargeted metabolomics identified 102 and 78 differentially accumulated metabolites in Q. acutissima and Q. wutaishanica, respectively, when the leaves were subjected to LTs (4 °C for 24 h). The carbohydrate and flavonoid metabolites contributed to the cold tolerance of both oak species. Succinate, an intermediate in the citric acid cycle, was significantly inhibited by LTs, a potential energy conservation strategy. Unlike Q. acutissima, Q. wutaishanica underwent metabolic reprogramming that significantly increased the contents of phosphatidylcholine, gallic acid, oxidized glutathione, shikimate, and phenylpyruvate under LTs. Our data provide a reference for characterizing the mechanisms involved in the response of oak species to cold temperatures and enhancing the cold tolerance of forest trees.

Knowledge, attitudes, and practices regarding COVID-19 and mental health status among college students in China: a cross-sectional study.

Background: During the prevalence of coronavirus disease 2019 (COVID-19), little was known about the knowledge, attitudes, practices (KAP) about COVID-19 and psychological status of college students in minority areas. This study aimed to evaluate the KAP of college students in minority areas of China toward COVID-19 and to provide a scientific basis for health education and policy formulation. Methods: From October 28th to November 6th, 2021, a cross-sectional study was conducted with 5,272 college students to examine KAP and its effects on mental health. Results: Regarding COVID-19 knowledge, the overall awareness rate was 24.11% (1,271). Regarding health attitudes, most students had positive attitudes about COVID-19 prevention and control (94.95%), and females had higher positive attitudes than males (OR: 1.920; CI: 1.494-2.469). Regarding preventive behaviors, more than half of the students took preventive measures (53.48%), and freshmen had the highest health behavior scores. In terms of psychological status, there were fewer females with depression and stress than males. Conclusion: College students in minority areas have positive health attitudes; however, their knowledge of COVID-19 prevention and control is low. Moreover, their precautionary behaviors are insufficient, and they have many negative emotions.

Genome-Wide Identification of Detoxification Genes in Wild Silkworm Antheraea pernyi and Transcriptional Response to Coumaphos.

For a half-century, the commercial wild silkworm, Antheraea pernyi, has been protected by coumaphos, which is an internal organophosphorus insecticide used to kill the potential parasitic fly larvae inside. Knowledge about the detoxification genes of A. pernyi as well as the detoxification mechanism for this species remains severely limited. In this study, we identified 281 detoxification genes (32 GSTs, 48 ABCs, 104 CYPs, and 97 COEs) in the genome of this insect, which are unevenly distributed over 46 chromosomes. When compared to the domesticated silkworm, Bombyx mori, a lepidopteran model species, A. pernyi has a similar number of ABCs, but a greater number of GSTs, CYPs, and COEs. By transcriptome-based expression analysis, we found that coumaphos at a safe concentration level significantly changed the pathways related to ATPase complex function and the transporter complex in A. pernyi. KEGG functional enrichment analysis indicated that protein processing in the endoplasmic reticulum was the most affected pathway after coumaphos treatment. Finally, we identified four significantly up-regulated detoxification genes (ABCB1, ABCB3, ABCG11, and ae43) and one significantly down-regulated detoxification gene (CYP6AE9) in response to coumaphos treatment, suggesting that these five genes may contribute to detoxification of coumaphos in A. pernyi. Our study provides the first set of detoxification genes for wild silkworms from Saturniidae and highlights the importance of detoxification gene repertoire in insect pesticide tolerance.

Comprehensive Analysis of Codon Usage in Quercus Chloroplast Genome and Focus on psbA Gene.

Quercus (oak) is an important economic and ecological tree species in the world, and it is the necessary feed for oak silkworm feeding. Chloroplasts play an important role in green plants but the codon usage of oak chloroplast genomes is not fully studied. We examined the codon usage of the oak chloroplast genomes in detail to facilitate the understanding of their biology and evolution. We downloaded all the protein coding genes of 26 non-redundant chloroplast reference genomes, removed short ones and those containing internal stop codons, and finally retained 50 genes shared by all genomes for comparative analyses. The base composition, codon bias, and codon preference are not significantly different between genomes but are significantly different among genes within these genomes. Oak chloroplast genomes prefer T/A-ending codons and avoid C/G-ending codons, and the psbA gene has the same preference except for the codons encoding amino acid Phe. Complex factors such as context-dependent mutations are the major factors affecting codon usage in these genomes, while selection plays an important role on the psbA gene. Our study provided an important understanding of codon usage in the oak chloroplast genomes and found that the psbA gene has nearly the same codon usage preference as other genes in the oak chloroplasts.

Highly covalent molecular cage based porous organic polymer: pore size control and pore property enhancement.

It remains a great challenge to effectively control the pore size in porous organic polymers (POPs) because of the disordered linking modes. Herein, we used organic molecular cages (OMCs), possessing the properties of fixed intrinsic cavities, high numbers of reactive sites and dissolvable processability, as building blocks to construct a molecular cage-based POP (TPP-pOMC) with high valency through covalent cross coupling reaction. In the formed TPP-pOMC, the originating blocking pore channels of TPP-OMC were "turned on" and formed fixed pore channels (5.3 Å) corresponding to the connective intrinsic cavities of cages, and intermolecular pore channels (1.34 and 2.72 nm) between cages. Therefore, TPP-pOMC showed significant enhancement in Brunauer-Emmett-Teller (BET) surface area and CO2 adsorption capacity.

Mitochondrial Genome Architecture and Evolutionary Origin of the Yao Silkworm, a Living Fossil of the Domestic Silkworm Bombyx mori (Lepidoptera: Bombycidae).

The Yao silkworm is a unique silkworm resource producing yellow flat plate silk that has only been reared by the Baiku Yao ethnic group in Nandan County, Guangxi Province, China for a thousand years. Here, we report the mitochondrial genomes (mitogenomes) of five Yao silkworm strains and 10 local Guangxi strains of the domestic silkworm (Bombyx mori) L. (Lepidoptera: Bombycidae), and use the resulting mitogenomes and the available Bombyx mitogenomes to characterize their genome architecture and trace the evolutionary origin of the Yao silkworm. The five Yao silkworm mitogenomes exhibited genome architectures identical to typical set of 37 mitochondrial genes (13 protein-coding genes, 22 transfer RNAs, and two ribosomal RNAs) and a high level of genome sequence similarity with the domestic silkworm. Mitogenome-based phylogenetic reconstruction provided solid evidence that the Yao silkworm shares a common ancestor with the domestic silkworm. Sliding window analysis uncovered a distinct variation pattern in the mitogenome between the Yao silkworm and the other domestic silkworm strains. The phylogenetic analyses revealed a basal placement of the Yao silkworm among all available domestic silkworm strains, indicating that the Yao silkworm is an ancient population of the domestic silkworm. Our data indicated that the Yao silkworm (B. mori) is a lineage of the domestic silkworm, which for the first time provides insights into the origin of the Yao silkworm.

First complete mitochondrial genome of Rhodinia species (Lepidoptera: Saturniidae): genome description and phylogenetic implication.

To explore the characteristics of the mitochondrial genome (mitogenome) of the squeaking silkmoths Rhodinia, a genus of wild silkmoths in the family Saturniidae of Lepidoptera, and reveal phylogenetic relationships, the mitogenome of Rhodinia fugax Butler was determined. This wild silkmoth spins a green cocoon that has potential significance in sericulture, and exhibits a unique feature that its larvae can squeak loudly when touched. The mitogenome of R. fugax is a circular molecule of 15,334 bp long and comprises 13 protein-coding genes, two ribosomal RNA genes, 22 transfer RNA genes, and an A + T-rich region, consistent with previous observations of Saturniidae species. The 370-bp A + T-rich region of R. fugax contains no tandem repeat elements and harbors several features common to the Bombycidea insects, but microsatellite AT repeat sequence preceded by the ATTTA motif is not present. Mitogenome-based phylogenetic analysis shows that R. fugax belongs to Attacini, instead of Saturniini. This study presents the first mitogenome for Rhodinia genus.

Transcriptomic analysis of Bombyx mori corpora allata with comparison to prothoracic glands in the final instar larvae.

The corpus allatum (CA) is an endocrine organ of insects that synthesizes juvenile hormone (JH). Yet little is known regarding the global gene expression profile for the CA, although JH signaling pathway has been well-studied in insects. Here, we report the availability of the transcriptome resource of the isolated CA from the final (fifth) instar larvae of the silkworm, Bombyx mori when the JH titer is low. We also compare it with prothoracic gland (PG) that produces the precursor of 20-hydroxyecdysone (20E), to find some common features in the JH and 20E related genes between the two organs. A total of 17,262 genes were generated using a combination of genome-guided assembly and annotation, in which 10,878 unigenes were enriched in 58 Gene Ontology terms, representing almost all expressed genes in the CA of the 5th instar larvae of B. mori. Transcriptome analysis confirmed that gene for Torso, the receptor of prothoracicotropic hormone (PTTH), is present in the PG but not in the CA. Transcriptome comparison and quantitative real time-PCR indicated that 11 genes related to JH biosynthesis and regulation and six genes for 20E are expressed in both the CA and PG, suggesting that the two organs may cross talk with each other through these genes. The temporal expression profiles of the two genes for the multifunctional neurohormonal factor sericotropin precursor and the uncharacterized protein LOC114249572, the most abundant in the CA and PG transcriptomes respectively, suggested that they might play important roles in the JH and 20E biosynthesis. The present work provides new insights into the CA and PG.

First complete mitochondrial genome of Antheraea pernyi Guérin-Méneville 1855 (Lepidoptera: Saturniidae) from North Korea.

This study reports the first complete mitochondrial genome of Antheraea pernyi Guérin-Méneville 1855 (Lepidoptera: Saturniidae) strain Dingzhou_1, a silkworm resource serving silk production in North Korea. The mitochondrial genome is circular with 15,573 bp in length encoding 37 typical mitochondrial genes (13 protein-coding genes, two ribosomal RNA genes, and 22 transfer RNA genes). The 553-bp A + T-rich region harbors a repeat region composed of 6 ∼ 38 bp tandem repeat units, as found in other known inbred strains from Chinese populations. The phylogenetic analysis clustered Dingzhou_1 from North Korea together with Chinese Liaoning population, suggesting that oak silkworm in North Korea might be introduced from her neighbor China Liaoning.

Characterization of the complete mitochondrial genome of Antheraea pernyi strain Luhong.

The present study for the first time describes the complete mitochondrial (mt) genome of Antheraea pernyi Guérin-Méneville 1855 strain Luhong, a genetic lethal mutant exhibiting especially red skin color. The mt genome is 15,563 bp in length that is the smallest among the sequenced A. pernyi inbred strains. This genome displays an identical genomic component and gene order to other six known A. pernyi mt genomes. The mt genome-based phylogenetic analysis clustered Luhong with four strains exhibiting yellow skin color, consistent with the traditional view that all of them belonged to the yellow blood lineage.

The complete mitochondrial genome of the wild silkmoth Antheraea yamamai from Heilongjiang, China (Lepidoptera: Saturniidae).

Here, we reported the complete mitochondrial genome of Antheraea yamamai Guérin-Méneville (1861) collected in Heilongjiang Province, China. The mitochondrial genome is 15,341 bp and encodes 13 protein-coding genes, two ribosomal RNA genes, and 22 transfer RNA genes. Sequence comparison identified 22 SNVs in the A. yamamai mitochondrial genomes between Chinese and Korean populations, indicating a low intraspecific variation between the two populations . Phylogenetic analyses with maximum-likelihood and Bayesian inference methods revealed a close relationship between A. yamamai and Antheraea frithi and supported the relationship among Antheraea species (((A. yamamai + A. frithi) + A. pernyi) + A. assamensis).

Anatomical Study of the Accessory Tendon of the Extensor Hallucis Longus Muscle and Its Clinical Application.

BACKGROUD: The accessory tendon of the extensor hallucis longus (ATEHL) muscle is a common abnormal structure, and its clinical significance remains debatable. In this study, we provide the incidence of the ATEHL and characterize its morphological types in Asian cadavers and investigate its clinical applications. METHODS: The tendons from 50 adult cadaveric feet, fixed in 10% formalin, were analyzed. We measured the length and width of both the ATEHL and the extensor hallucis brevis (EHB). RESULTS: All dissected specimens had an ATEHL. The first metatarsophalangeal joint was surrounded by an accessory tendon that inserted onto the joint capsule and the dorsal base of the proximal phalanx. We classified the ATEHL into 3 types based on their directions. Differences in ATEHL type based on sex were not statistically significant. CONCLUSIONS: We found an ATEHL in all cadaveric specimens in this study. We surmise that the ATEHL acts as an antagonist with the EHB when the toe is extending, which might help prevent the occurrence of hallux valgus deformity.

Five metastasis-related mRNAs signature predicting the survival of patients with liver hepatocellular carcinoma.

BACKGROUNDS: Liver hepatocellular carcinoma (HCC) is one of the most malignant tumors, of which prognosis is unsatisfactory in most cases and metastatic of HCC often results in poor prognosis. In this study, we aimed to construct a metastasis- related mRNAs prognostic model to increase the accuracy of prediction of HCC prognosis. METHODS: Three hundred seventy-four HCC samples and 50 normal samples were downloaded from The Cancer Genome Atlas (TCGA) database, involving transcriptomic and clinical data. Metastatic-related genes were acquired from HCMBD website at the same time. Two hundred thirty-three samples were randomly divided into train dataset and test dataset with a proportion of 1:1 by using caret package in R. Kaplan-Meier method and univariate Cox regression analysis and lasso regression analysis were performed to obtain metastasis-related mRNAs which played significant roles in prognosis. Then, using multivariate Cox regression analysis, a prognostic prediction model was established. Transcriptome and clinical data were combined to construct a prognostic model and a nomogram for OS evaluation. Functional enrichment in high- and low-risk groups were also analyzed by GSEA. An entire set based on The International Cancer Genome Consortium(ICGC) database was also applied to verify the model. The expression levels of SLC2A1, CDCA8, ATG10 and HOXD9 are higher in tumor samples and lower in normal tissue samples. The expression of TPM1 in clinical sample tissues is just the opposite. RESULTS: One thousand eight hundred ninety-five metastasis-related mRNAs were screened and 6 mRNAs were associated with prognosis. The overall survival (OS)-related prognostic model based on 5 MRGs (TPM1,SLC2A1, CDCA8, ATG10 and HOXD9) was significantly stratified HCC patients into high- and low-risk groups. The AUC values of the 5-gene prognostic signature at 1 year, 2 years, and 3 years were 0.786,0.786 and 0.777. A risk score based on the signature was a significantly independent prognostic factor (HR = 1.434; 95%CI = 1.275-1.612; P < 0.001) for HCC patients. A nomogram which incorporated the 5-gene signature and clinical features was also built for prognostic prediction. GSEA results that low- and high-risk group had an obviously difference in part of pathways. The value of this model was validated in test dataset and ICGC database. CONCLUSION: Metastasis-related mRNAs prognostic model was verified that it had a predictable value on the prognosis of HCC, which could be helpful for gene targeted therapy.

Comparison of bacterial communities between midgut and midgut contents in two silkworms, Antheraea pernyi and Bombyx mori.

Bacterial communities living inside the midgut of insects have been attracting increasing interest. Previous studies have shown that both the midgut and midgut contents harbor bacterial communities. However, whether the bacterial communities of the insect midgut are similar to those of the insect midgut contents (including the peritrophic membrane, food particles, and digestive fluids secreted by the midgut in this study) remains unknown. In the present study, we analyzed two economically important silkworms, the Chinese oak silkworm Antheraea pernyi (Lepidoptera: Saturniidae) and the mulberry silkworm Bombyx mori (Lepidoptera: Bombycidae), through Illumina MiSeq technology to address this issue. In A. pernyi larvae, 17 phyla and 162 genera were found in the midgut, while 7 phyla and 36 genera were found in the midgut contents. For B. mori larvae, 30 phyla and 465 genera were found in the midgut, but 22 phyla and 344 genera were found in the midgut contents. This evidence from the two silkworms suggests that the bacterial composition and diversity in the midgut are more diverse than those in the midgut contents. Principal component analysis revealed a significant difference in the bacterial community structure between the midgut and midgut contents of B. mori. To our knowledge, this is the first study to compare the bacterial communities between the midgut and midgut contents in insects, and the results will provide useful information for probing the functional differentiation within the midgut in the future.

Identification of genes involved in sex pheromone biosynthesis and metabolic pathway in the Chinese oak silkworm, Antheraea pernyi.

The Chinese oak silkworm, Antheraea pernyi, has not only been semi-domesticated as an important economical insect but also used for genetic research. The female moths of A. pernyi employ a pheromone blend containing (E,Z)-6,11-hexadecadienal (E6,Z11-16:Ald), (E,Z)-6,11-hexadecadienyl acetate (E6,Z11-16:OAc), and (E,Z)-4,9-tetradecadienyl acetate (E4,Z9-14:OAc). While its biosynthesis pathway is largely unknown. By deep sequencing and de novo assembly of sex pheromone gland (PG) transcriptome, we identified 141 candidate genes that are putatively related to pheromone biosynthesis, degradation, and chemoreception in A. pernyi. Gene expression patterns and phylogenetic analysis revealed that two desaturases (AperDES1 and 2), two fatty acid reductase (AperFAR1 and 2), and three acetyltransferase genes (AperACT1, 2 and 3) showed PG-biased or specific expression and were phylogenetically related to genes known to be involved in pheromone synthesis in other species. Furthermore, two carboxylesterases (AperCOE6 and 11) and two chemosensory protein (AperCSP1 and 6) were also expressed specifically or predominantly in the PGs, which might be related to sex pheromone degradation and transportation, respectively. Based on these results, the sex pheromone biosynthesis and metabolic pathway was proposed in A. pernyi. This study provides some crucial candidates for further functional elucidation, and may be used for interfering sexual communication in other Saturniidae pests.

Characterization of an Ecdysteroid-Regulated 16 kDa Protein Gene in Chinese Oak Silkworm, Antheraea pernyi (Lepidoptera: Saturniidae).

A large number of ecdysteroid-regulated 16 kDa proteins (ESR16s) of insects have been isolated and annotated in GenBank; however, knowledge on insect ESR16s remain limited. In the present study, we characterized an ecdysteroid-regulated 16 kDa protein gene isolated in Chinese oak silkworm, Antheraea pernyi Guérin-Méneville ('ApESR16' in the following), an important silk-producing and edible insect. The obtained cDNA sequence of ApESR16 is 1,049 bp, harboring an open reading frame of 441 bp that encodes a polypeptide of 146 amino acids. CD-search revealed that ApESR16 contains the putative cholesterol/lipid binding sites on conserved domain Npc2_like (Niemann-Pick type C-2) belonging to the MD-2-related lipid-recognition superfamily. Sequence comparison revealed that ApESR16 exhibits 51-57% identity to ESR16s of lepidopteran insects, 36-41% identity to ESR16 or NPC2a of nonlepidopteran insects, and 28-32% identity to NPC2a of vertebrates, indicating a high sequence divergence during the evolution of animals. Phylogenetic analysis found that the used sequences were divided into two groups corresponding to vertebrates and invertebrates, and the used insect sequences were also well clustered according to their families. The A. pernyi ESR16 mRNA is expressed during all four developmental stages and in all tested tissues. Injection of 20-hydroxyecdysone (20-E) into A. pernyi diapausing pupae triggering diapause termination induced upregulation of ESR16 mRNA compared to the diapausing pupae, with the highest expression level at day 2 in the ovaries but day 12 in the fat body. Our results suggested that ApESR16 might be a diapause-related gene and plays a vital role in the pupal diapause of A. pernyi.

A high level of chloroplast genome sequence variability in the Sawtooth Oak Quercus acutissima.

The Sawtooth Oak, Quercus acutissima Carruth., is an economically and ecologically important tree species in the family Fagaceae with a wide distribution in China. Here, we examined its intraspecific chloroplast (cp) genome variability using available and a newly sequenced genome. The new cp genome comes from a Q. acutissima individual collected from Shenyang (Northeast China; "Q. acutissima Shenyang" in the following), and then is compared with two recently published cp genomes from Tongchuan (Northwest China) and Nanjing (East China). The cp genome of Q. acutissima Shenyang exhibits a slightly larger genome size than the other two individuals, although each encodes 86 protein-coding genes, 40 tRNA genes and eight rRNA genes. We also found the length difference for the IR/SC boundary region among the three cp genomes. Sequence comparison revealed a high intraspecific genetic divergence: the three cp genomes differ by 332 sequence patterns including 77 single nucleotide polymorphisms, and 255 indels (each gap considered) scattering across 67 regions. Phylogenetic analyses based on the cp genome recovered the split between the subgenus Cerris and the subgenus Quercus, but revealed that three Q. acutissima individuals did not cluster together, indicating that even complete cp genome data fail to reproduce species boundaries in Asian members of section Cerris. Our results show that more complete plastomes covering remote ranges needs to be sequenced to provide a solid backbone for future population-scale in-depth studies and phylogenetic analysis of section Cerris.

Effects of D-arginine on Porphyromonas gingivalis biofilm.

Porphyromonas gingivalis (P. gingivalis) is one of the major pathogenic bacteria of periodontitis or peri-implantitis. P. gingivalis tends to attach to the implant's neck with the formation of biofilm, leading to peri-implantitis. d-arginine has been shown to have a potential antimicrobial role. In this study, P. gingivalis was cultured in Brain Heart Infusion broth together with d-arginine. After 3 days (inhibition) or 6 days (dissociation), these were characterized using crystal violet (CV) staining for the biofilm, extracellular polysaccharide (EPS) production from the biofilm, and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay for biofilm activation. Furthermore, the P. gingivalis biofilm was observed by scanning electron microscopy (SEM). d-arginine effectively reduced biomass accumulation and promoted dissociation at concentrations of ≥50 mM and 100 mM, respectively. Through CV staining, d-arginine concentrations of EPS production from the biofilm for inhibition and dissociation effects was ≥50 mM and 100 mM, respectively. In addition, d-arginine affected biofilm activation for the corresponding concentrations: ≥60 mM for inhibition and ≥90 mM for dispersal. Under SEM observation, d-arginine changed the P. gingivalis biofilm structure in relatively high concentrations for inhibition or dissociation, respectively. The authors concluded that d-arginine could inhibit the formation of P. gingivalis biofilm and promote the dissociation of P. gingivalis biofilm.

The complete mitochondrial genome of antheraea pernyi strain qing_6 (lepidoptera: Saturniidae).

Here, we report the complete mitochondrial (mt) genome of Antheraea pernyi Qing_6, an improved strain serving silk production and edible insect resource for 50 years in Northeast China. The circular mt genome spans 15,572 bp in length and contains 37 typical coding genes (13 protein-coding genes, two ribosomal RNA genes, 22 transfer RNA genes). Its A + T-rich region is 552 bp in size exhibiting identical sequence with the first modern improved strain Qinghuang_1. Comparison analysis identified only 12 variable sites (5 substitutions and 7 indels) between Qing_6 and Qinghuang_1. The phylogenetic analysis also clustered Qing_6 and Qinghuang_1 together first, which was in line with the breeding history of the two strains.