Characterization of Flavor Compounds in Chinese Indigenous Sheep Breeds Using Gas Chromatography-Ion Mobility Spectrometry and Chemometrics.

This study analyzed the flavor compounds in the meat of four indigenous breeds of Chinese sheep through the use of gas chromatography-ion mobility spectrometry (GC-IMS). GC-IMS provided information on the characteristics and strength of 71 volatile flavor compounds (monomers and dimers), with aldehydes, alcohols and ketones being the most abundant in all types of sheep meat. The compounds with higher intensity peaks in the sheep meat were aldehydes (n-nonanal, octanal, heptanal, 3-methylbutanal, and hexanal), alcohols (1-octen-3-ol, hexanol, and pentanol), ketones (3-hydroxy-2-butanon, 2-butanone, and 2-propanone), esters (methyl benzoate), and thiazole (trimethylthiazole). The volatile flavor components in the meat of the different breeds of sheep obtained via GC-IMS were further differentiated using principal component analysis. In addition, orthogonal partial least squares discriminant analysis (OPLS-DA) and variable importance on projection (VIP) were used to determine the characteristic flavor compounds in the meats of different breeds of sheep, and 21 differentially volatile components were screened out based on having a VIP above 1. These results indicate that GC-IMS combined with multivariate analysis is a convenient and powerful method for characterizing and discriminating sheep meat.

Inhibitor of Myom3 inhibits proliferation and promotes differentiation of sheep myoblasts.

Skeletal muscle quality and yield are important production traits in livestock, and improving skeletal muscle quality while increasing its yield is an important goal of economic breeding. The proliferation and differentiation process of sheep myoblasts directly affects the growth and development of their muscles, thereby affecting the yield of mutton. Myomesin 3 (Myom3), as a functional gene related to muscle growth, currently lacks research on its function in myoblasts. This study aims to investigate the effect of the Myom3 gene on the proliferation and differentiation of sheep myoblasts and its potential molecular mechanisms. The results showed that inhibitor of Myom3 in the proliferation phase of myoblasts resulted in significant downregulation of the proliferation marker gene paired box 7 (Pax7) and myogenic regulatory factors (MRFs; Myf5, Myod1, Myog, P < 0.01), a significant decrease in the EdU-positive cell rate (P < 0.05), and a significant increase in the cell apoptosis rate (P < 0.01), which inhibited the proliferation of myoblasts and promoted their apoptosis. During the differentiation phase of myoblasts, the inhibitor of Myom3 resulted in significant downregulation of the Pax7 gene, upregulation of MRFs (Myod1, Myog, P < 0.05), and a significant increase in fusion index (P < 0.05), promoting the differentiation of myoblasts. Further transcriptome sequencing revealed that differentially expressed genes in the Myom3 interference group were mainly enriched in the MAPK signaling pathway, TNF signaling pathway, and IL-17 signaling pathway. In summary, the inhibitor of Myom3 inhibits myoblast proliferation and promotes myoblast differentiation. Therefore, Myom3 has a potential regulatory effect on the growth and development of sheep muscles, and in-depth functional research can be used for molecular breeding practices in sheep.

A novel MOF-808 derived material for oxidative desulfurization: the synergistic effect of hydrophobicity and electron transfer.

A functionalized modified metal-organic framework material, T-MOF-808, was synthesized through hydrophobic modification with tetraethyl orthosilicate (TEOS) and chlorotrimethylsilane (TMCS). Then a supported oxidative desulfurization catalyst, [C12Py]3(NH4)3Mo7O24/T-MOF-808(s), was prepared by using a heteropoly acid ionic liquid as the active component. The prepared samples were characterized using FT-IR, XRD, SEM, TEM, XPS, etc. [C12Py]3(NH4)3Mo7O24/T-MOF-808(s) was used in the oxidative desulfurization of dibenzothiophene (DBT). At the same time, the effects of different loadings of the active component, oxygen sulfur ratios, reaction temperatures, and reaction time were also investigated. [C12Py]3(NH4)3Mo7O24/T-MOF-808-15%(s) could oxidize 100% of DBT in 40 min at 60 °C. Significantly, the catalyst exhibited no discernible decline in catalytic activity after 14 runs. In addition, the efficiency of sulfur removal was 85.76% in actual diesel oil. It was found that the cooperative impact of hydrophobic modification and electron transfer makes an important contribution to the high activity. The hydrophobic modification provides a novel approach for using MOF materials in the oxidative desulfurization process.

Chromosome-level genome assembly of Guide Black-Fur sheep (Ovis aries).

Guide Black-Fur sheep (GD) is a breed of Tibetan sheep (Ovis aries) that lives in the Qinghai-Tibetan plateau region at an altitude of over 4,000 m. However, a lack of genomic information has made it difficult to understand the high-altitude adaptation of these sheep. We sequenced and assembled the GD reference genome using PacBio, Hi-C, and Illumina sequencing technologies. The final assembled genome size was 2.73 Gb, with a contig N50 of 20.30 Mb and a scaffold N50 of 107.63 Mb. The genome is predicted to contain 20,759 protein-coding genes, of which 98.42 have functional annotations. Repeat elements account for approximately 52.2% of the genomic landscape. The completeness of the GD genome assembly is highlighted by a BUSCO score of 93.1%. This high-quality genome assembly provides a critical resource for future molecular breeding and genetic improvement of Tibetan sheep.

Delta-like noncanonical notch ligand 2 regulates the proliferation and differentiation of sheep myoblasts through the Wnt/ß-catenin signaling pathway.

This study delved into the role of delta-like noncanonical notch ligand 2 (DLK2) in the cell cycle, proliferation, apoptosis, and differentiation of myoblasts, as well as its interaction with the classical Wnt/ß-catenin signaling pathway in regulating myoblast function. The research revealed that upregulation of DLK2 in myoblasts during the proliferation phase enhanced myoblast proliferation, facilitated cell cycle progression, and reduced apoptosis. Conversely, downregulation of DLK2 expression using siRNA during the differentiation phase promoted myoblast hypertrophy and fusion, suppressed the expression of muscle fiber degradation factors, and expedited the differentiation process. DLK2 regulates myoblasts function by influencing the expression of various factors associated with the Wnt/ß-catenin signaling pathway, including CTNNB1, FZD1, FZD6, RSPO1, RSPO4, WNT4, WNT5A, and adenomatous polyposis coli. In essence, DLK2, with the involvement of the Wnt/ß-catenin signaling pathway, plays a crucial regulatory role in the cell cycle, proliferation, apoptosis, and differentiation of myoblasts.

Construction of a high-density genetic map and QTL localization of body weight and wool production related traits in Alpine Merino sheep based on WGR.

BACKGROUND: The Alpine Merino is a new breed of fine-wool sheep adapted to the cold and arid climate of the plateau in the world. It has been popularized in Northwest China due to its superior adaptability as well as excellent production performance. Those traits related to body weight, wool yield, and wool fiber characteristics, which are economically essential traits in Alpine Merino sheep, are controlled by QTL (Quantitative Trait Loci). Therefore, the identification of QTL and genetic markers for these key economic traits is a critical step in establishing a MAS (Marker-Assisted Selection) breeding program. RESULTS: In this study, we constructed the high-density genetic linkage map of Alpine Merino sheep by sequencing 110 F1 generation individuals using WGR (Whole Genome Resequencing) technology. 14,942 SNPs (Single Nucleotide Polymorphism) were identified and genotyped. The map spanned 2,697.86 cM, with an average genetic marker interval of 1.44 cM. A total of 1,871 high-quality SNP markers were distributed across 27 linkage groups, with an average of 69 markers per LG (Linkage Group). Among them, the smallest genetic distance is 19.62 cM for LG2, while the largest is 237.19 cM for LG19. The average genetic distance between markers in LGs ranged from 0.24 cM (LG2) to 3.57 cM (LG17). The marker density in the LGs ranged from LG14 (39 markers) to LG1 (150 markers). CONCLUSIONS: The first genetic map of Alpine Merino sheep we constructed included 14,942 SNPs, while 46 QTLs associated with body weight, wool yield and wool fiber traits were identified, laying the foundation for genetic studies and molecular marker-assisted breeding. Notably, there were QTL intervals for overlapping traits on LG4 and LG8, providing potential opportunities for multi-trait co-breeding and further theoretical support for selection and breeding of ultra-fine and meaty Alpine Merino sheep.

Key genes and metabolites that regulate wool fibre diameter identified by combined transcriptome and metabolome analysis.

BACKGROUND: Fibre diameter is an important economic trait of wool fibre. As the fibre diameter decreases, the economic value of wool increases. Therefore, understanding the mechanism of wool fibre diameter regulation is important in improving the value of wool. RESULTS: In this study, we used non-targeted metabolome and reference transcriptome data to detect differences in metabolites and genes in groups of Alpine Merino sheep with different wool fibre diameter gradients, and integrated metabolome and transcriptome data to identify key genes and metabolites that regulate wool fibre diameter. We found 464 differentially abundant metabolites (DAMs) and 901 differentially expressed genes (DEGs) in four comparisons of groups with different wool fibre diameters. Approximately 25% of the differentially abundant metabolites were lipid and lipid-like molecules. These molecules were predicted to be associated with skin development and keratin filament by gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) functional enrichment analyses. Key genes, including COL5A2, COL5A3, CREB3L4, COL1A1, and SFRP4, were identified by gene set enrichment analysis. CONCLUSIONS: Key genes regulating wool fibre diameter were identified, the effects of lipid molecules on wool performance were investigated, and potential synergies between genes and metabolites were postulated, providing a theoretical framework for fine wool sheep breeding.

Selection signatures of wool color in Gangba sheep revealed by genome-wide SNP discovery.

BACKGROUND: Gangba sheep as a famous breed of Tibetan sheep, its wool color is mainly white and black. Gangba wool is economically important as a high-quality raw material for Tibetan blankets and Tibetan serge. However, relatively few studies have been conducted on the wool color of Tibetan sheep. RESULTS: To fill this research gap, this study conducted an in-depth analysis of two populations of Gangba sheep (black and white wool color) using whole genome resequencing to identify genetic variation associated with wool color. Utilizing PCA, Genetic Admixture, and N-J Tree analyses, the present study revealed a consistent genetic relationship and structure between black and white wool colored Gangba sheep populations, which is consistent with their breed history. Analysis of selection signatures using multiple methods (FST, π ratio, Tajima's D), 370 candidate genes were screened in the black wool group (GBB vs GBW); among them, MC1R, MLPH, SPIRE2, RAB17, SMARCA4, IRF4, CAV1, USP7, TP53, MYO6, MITF, MC2R, TET2, NF1, JAK1, GABRR1 genes are mainly associated with melanin synthesis, melanin delivery, and distribution. The enrichment results of the candidate genes identified 35 GO entries and 19 KEGG pathways associated with the formation of the black phenotype. 311 candidate genes were screened in the white wool group (GBW vs GBB); among them, REST, POU2F1, ADCY10, CCNB1, EP300, BRD4, GLI3, and SDHA genes were mainly associated with interfering with the differentiation of neural crest cells into melanocytes, affecting the proliferation of melanocytes, and inhibiting melanin synthesis. 31 GO entries and 22 KEGG pathways were associated with the formation of the white phenotype. CONCLUSIONS: This study provides important information for understanding the genetic mechanism of wool color in Gangba, and provides genetic knowledge for improving and optimizing the wool color of Tibetan sheep. Genetic improvement and selective breeding to produce wool of specific colors can meet the demand for a diversity of wool products in the Tibetan wool textile market.

Motion measurements of explosive shock waves based on an event camera.

Shock wave measurement is vital in assessing explosive power and designing warheads. To obtain satisfactory observation data of explosive shock waves, it is preferable for optical sensors to possess high-dynamic range and high-time resolution capabilities. In this paper, the event camera is first employed to observe explosive shock waves, leveraging its high dynamic range and low latency. A comprehensive procedure is devised to measure the motion parameters of shock waves accurately. Firstly, the plane lines-based calibration method is proposed to compute the calibration parameters of the event camera, which utilizes the edge-sensitive characteristic of the event camera. Then, the fitted ellipse parameters of the shock wave are estimated based on the concise event data, which are gained by utilizing the characteristics of the event triggering and shock waves' morphology. Finally, the geometric relationship between the ellipse parameters and the radius of the shock wave is derived, and the motion parameters of the shock wave are estimated. To verify the performance of our method, we compare our measurement results in the TNT explosion test with the pressure sensor results and empirical formula prediction. The relative measurement error compared to pressure sensors is the lowest at 0.33% and the highest at 7.58%. The experimental results verify the rationality and effectiveness of our methods.

Widespread reductions in cortical thickness following ketamine abuse.

BACKGROUND: Esketamine is a version of ketamine that has been approved for treatment-resistant depression, but our previous studies showed a link between non-medical use of ketamine and brain structural and functional alterations, including dorsal prefrontal grey matter reduction among chronic ketamine users. In this study, we sought to determine cortical thickness abnormalities following long-term, non-medical use of ketamine. METHODS: We acquired structural brain images for patients with ketamine use disorder and drug-free healthy controls. We used FreeSurfer software to measure cortical thickness for 68 brain regions. We compared cortical thickness between the 2 groups using analysis of covariance with covariates of age, gender, educational level, smoking, drinking, and whole-brain mean cortical thickness. RESULTS: We included images from 95 patients with ketamine use disorder and 169 controls. Compared with healthy controls, patients with ketamine use disorder had widespread decreased cortical thickness, with the most extensive reductions in the frontal (including the dorsolateral prefrontal cortex) and parietal (including the precuneus) lobes. Increased cortical thickness was not observed among ketamine users relative to comparison participants. Estimated total lifetime ketamine consumption was correlated with reductions in the right inferior parietal and the right rostral middle frontal cortical thickness. LIMITATIONS: We conducted a retrospective cross-sectional study, but longitudinal studies are needed to further validate decreased cortical thickness after nonmedical use of ketamine. CONCLUSION: This study provided evidence that, compared with healthy controls, chronic ketamine users have widespread reductions in cortical thickness. Our study underscores the importance of the long-term effects of ketamine on brain structure and serves as a reference for the antidepressant use of ketamine.

DIA-Based Proteomic Analysis Reveals MYOZ2 as a Key Protein Affecting Muscle Growth and Development in Hybrid Sheep.

Hybridization of livestock can be used to improve varieties, and different hybrid combinations produce unique breeding effects. In this study, male Southdown and Suffolk sheep were selected to hybridize with female Hu sheep to explore the effects of male parentage on muscle growth and the development of offspring. Using data-independent acquisition technology, we identified 119, 187, and 26 differentially abundant proteins (DAPs) between Hu × Hu (HH) versus Southdown × Hu (NH), HH versus Suffolk × Hu (SH), and NH versus SH crosses. Two DAPs, MYOZ2 and MYOM3, were common to the three hybrid groups and were mainly enriched in muscle growth and development-related pathways. At the myoblast proliferation stage, MYOZ2 expression decreased cell viability and inhibited proliferation. At the myoblast differentiation stage, MYOZ2 expression promoted myoblast fusion and enhanced the level of cell fusion. These findings provide new insights into the key proteins and metabolic pathways involved in the effect of male parentage on muscle growth and the development of hybrid offspring in sheep.

Incremental diagnostic value of virtual non-contrast dual-energy CT for the diagnosis of choledocholithiasis over conventional unenhanced CT.

PURPOSE: The purpose of this study was to evaluate the incremental diagnostic value of virtual non-contrast (VNC) images derived from unenhanced dual-energy computed tomography (CT) for the diagnosis of choledocholithiasis by comparison with conventional unenhanced CT. MATERIALS AND METHODS: Eighty-nine patients with gallbladder stones who had undergone both abdominal unenhanced dual-energy CT and magnetic resonance cholangiopancreatography (MRCP) were retrospectively included. There were 53 men and 36 women, with a mean age of 54 ± 13 (standard deviation) years (age range: 41-67 years). VNC and conventional CT images were generated. Two independent radiologists evaluated the presence of choledocholithiasis in three reading sessions (session 1, conventional unenhanced CT images; session 2, VNC images; session 3, conventional unenhanced CT plus VNC images). The reading time to identify choledocholithiasis was recorded. Inter-reader agreement was measured by using the Cohen kappa (κ) test. Incremental diagnostic value of VNC imaging when combined with conventional unenhanced CT was assessed based on discrimination (area under the curve [AUC]) and clinical utility (decision curve analysis). The diagnostic performance of dual-energy CT and that of MRCP were compared using DeLong test. RESULTS: Using the standard of reference, 39 patients (39/89; 44%) had choledocholithiasis. The diagnosis of choledocholithiasis was improved using VNC images in combination with conventional unenhanced CT (AUC, 0.877; 95% confidence interval [CI]: 0.808, 0.947) by comparison with conventional unenhanced CT alone (AUC, 0.789; 95% CI: 0.718, 0.877) (P = 0.033) and achieved almost perfect inter-reader agreement (κ = 0.88; 95% CI: 0.72, 1.00) for the diagnosis of choledocholithiasis, without lengthening the median reading time (16.2 s for the combination of conventional CT and VNC images vs. 14.7 s for conventional CT alone; P= 0.325). Based on decision curve analysis, adding VNC imaging to conventional unenhanced CT resulted in a higher net benefit among most of decision thresholds. No differences in diagnostic performance were found between the combination of conventional unenhanced CT and VNC imaging (AUC, 0.877; 95% CI: 0.808, 0.947) and MRCP (AUC, 0.913; 95% CI: 0.852, 0.974) (P= 0.458). CONCLUSIONS: VNC images derived from dual-energy unenhanced CT have incremental diagnostic value for the diagnosis of choledocholithiasis. Unenhanced CT in a dual-energy mode may be a useful tool for the diagnosis of choledocholithiasis.

Alterations and Significance of Computed Tomography Pulmonary Angiography-Derived Parameters in Older Patients With Acute Pulmonary Embolism.

OBJECTIVE: This study aimed to investigate changes of computed tomography pulmonary angiography (CTPA)-derived parameters in older adults with acute pulmonary embolism (APE). METHODS: According to the pulmonary artery obstruction index (PAOI), patients with APE were divided into the A1 (PAOI ≥30%, n = 57) and A2 (PAOI <30%, n = 40) groups. Participants without APE were placed in group B (n = 170). The left atrial (LA) and left ventricular (LV) parameters among the three groups were compared, and the parameter changes in the 44 patients with APE were analyzed before and after treatment. The correlation between APE severity and the parameters was analyzed using correlation analysis. RESULTS: The left-to-right diameters (LR) of LA, and LR × anteroposterior diameters (AP) of LA and LV: A1 < A2 < B; LR of LV: A1 < A2, B; AP of LA and LV: A1, A2 < B. After treatment, LR and LR × AP of the LA and LV were significantly increased in the group A1 and LR of the LV and LR × AP of the LA and LV were elevated in the group A2. Acute pulmonary embolism severity was closely associated with LR × AP ( r = -0.557) and LR ( r = -0.477) of LA. CONCLUSIONS: With an increase in the degree of obstruction, older adults had a smaller LA and LV. Furthermore, the LR and LR × AP values of the LA were significantly decreased. These results contribute to in-time risk stratification.

Multimodal steerable earthworm-inspired soft robot based on vacuum and positive pressure powered pneumatic actuators.

This article presents a multimodal steerable earthworm-inspired soft robot based on vacuum and positive pressure powered pneumatic actuators capable of crawling both inside pipelines and on planar surfaces. The optimized modular vacuum pressure-driven actuator can generate deformation and anchoring motion through a unified structure under low vacuum pressure, giving it significant speed advantages and multi-modal locomotion capabilities. Meanwhile, the positive pressure powered actuator (PPPA) enables the robot to achieve controlled multi-directional and multi-degrees-of-freedom steering, moreover, enhances the consistency of the driving mechanism. The incorporation of front-end pressure sensing enables the robot to autonomously detect and evaluate pressure, facilitating automatic obstacle avoidance through the activation of corresponding turning units of PPPA. In the process of optimizing motion parameters, the overall motion efficiency has been improved by 16.7% by improving the control law. Through adjustments and optimizations of the interval time (cycle time), the robot is able to achieve a speed of 7.16 mm s-1during planar locomotion and 1.94 mm s-1during in-pipe locomotion. Using the developed robot, we conducted a series of turning experiments, including surface obstacle avoidance and cross-plane crawling, which demonstrated its enhanced capability in cross-plane steering and locomotion. Its related speed indicators showcase superior overall performance compared to other developed robots of the same type.

Association of SLIT3 and ZNF280B Gene Polymorphisms with Wool Fiber Diameter.

The SLIT3 gene encodes a secreted protein, and the ZNF280B gene is a member of the transcription factor family. Both genes have multiple biological functions. This study was conducted to investigate the association between SLIT3 and ZNF280B gene polymorphisms and wool fiber diameter and to determine potential molecular marker sites for breeding sheep with fine wool. We used Kompetitive Allele-Specific PCR to type the single nucleotide polymorphism (SNP) loci in the SLIT3 and ZNF280B genes within 1081 Alpine Merino sheep and associated these SNPs with wool fiber diameter. The results revealed one SNP in SLIT3 and ZNF280B, which were each related to sheep fiber diameter. The wool fiber diameters of sheep with the CC genotype in SLIT3 g.478807C>G and AA genotype in ZNF280B g.677G>A were the smallest and differed significantly from the diameters of other genotypes (p < 0.05). These results suggest potential molecular marker sites for fine-wool sheep breeding.

Insights from colony formation: The necessity to consider morphotype when assessing the effect of antibiotics on cyanobacteria.

Colonial cyanobacteria have been identified as the primary contributor to the global occurrence of cyanobacterial harmful algal blooms (cyanoHABs), which are further intensified by the presence of "pseudo-persistent" antibiotics. Nevertheless, the impact of antibiotics on the growth and size of colonial cyanobacteria remains unclear. In this study, the response of cyanobacterium Microcystis to varying doses of antibiotics was assessed (0, 0.1, 0.5, 1, 10, and 50 µg L-1) by comparing the unicellular and colonial morphotypes. Interestingly, the morphological structure of cyanobacteria plays a significant role in their reaction to antibiotics. In comparison to the unicellular morphotype, the colonial morphotype exhibited a greater promotion in growth rate (11 %-22 %) to low doses of antibiotics and was less inhibited (-121 %--62 %) under high doses. Furthermore, antibiotics may affect the size of cyanobacterial colonies by disrupting the secretion of algal organic matter, which also exhibited a two-phase pattern. This work sheds light on the significance of methodology research involving both unicellular and colonial cyanobacteria. Future research and lake management should prioritize studying the morphological traits of cyanobacteria under different levels of antibiotic exposure. This approach may lead to novel strategies for predicting cyanoHABs under antibiotic pollution more effectively.

Investigation of Polymer-Assisted CO2 Flooding to Enhance Oil Recovery in Low-Permeability Reservoirs.

CO2 flooding is a favorable technical means for the efficient development of low-permeability reservoirs, and it can also contribute to the realization of net-zero CO2 emissions. However, due to the unfavorable viscosity ratio and gravity overriding effect, CO2 channeling will inevitably occur, seriously affecting its storage and displacement effects. This paper conducts a systematic study on the application of polymer-assisted CO2 flooding in low-permeability reservoirs. Firstly, the polymer agent suitable for low-permeability reservoirs is optimized through the viscosity-increasing, rheological, and temperature- and salt-resistant properties of the solution. Then, the injectivity performance, resistance-increasing ability, and profile-improving effect of the polymer solution were evaluated through core experiments, and the optimum concentration was optimized. Finally, the enhanced oil recovery (EOR) effects of polymer-assisted and water-assisted CO2 flooding were compared. The results show that the temperature-resistant polymer surfactant (TRPS) has a certain viscosity-increasing performance, good temperature resistance performance, and can react with CO2 to increase the solution viscosity significantly. Meanwhile, TRPS has good injection performance and resistance-increasing effect. The resistance increasing factor (η and η') of TRPS-assisted CO2 flooding increases with increased permeability, the concentration of TRPS solution, and injection rounds. Considering η' and the profile improvement effect comprehensively, the application concentration of TRPS should be 1000 mg/L. The EOR effect of TRPS-assisted CO2 flooding is 8.21% higher than that of water-assisted CO2 flooding. The main effective period is in the first and second rounds, and the best injection round is three. The research content of this paper can provide data support for the field application of polymer-assisted CO2 flooding in low-permeability reservoirs.

Proteome Analysis of Alpine Merino Sheep Skin Reveals New Insights into the Mechanisms Involved in Regulating Wool Fiber Diameter.

Wool fiber is a textile material that is highly valued based on its diameter, which is crucial in determining its economic value. To analyze the molecular mechanisms regulating wool fiber diameter, we used a Data-independent acquisition-based quantitative proteomics approach to analyze the skin proteome of Alpine Merino sheep with four fiber diameter ranges. From three contrasts of defined groups, we identified 275, 229, and 190 differentially expressed proteins (DEPs). Further analysis using Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways revealed that pathways associated with cyclic adenosine monophosphate and peroxisome proliferator-activated receptor signaling are relevant to wool fiber diameter. Using the K-means method, we investigated the DEP expression patterns across wool diameter ranges. Using weighted gene co-expression network analysis, we identified seven key proteins (CIDEA, CRYM, MLX, TPST2, GPD1, GOPC, and CAMK2G) that may be involved in regulating wool fiber diameter. Our findings provide a theoretical foundation for identifying DEPs and pathways associated with wool fiber diameter in Alpine Merino sheep to enable a better understanding of the molecular mechanisms underlying the genetic regulation of wool fiber quality.

Epigenetic mechanism of Gtl2-miRNAs causes the primitive sheep characteristics found in purebred Merino sheep.

BACKGROUND: It is not uncommon for some individuals to retain certain primitive characteristics even after domestication or long-term intensive selection. Wild ancestors or original varieties of animals typically possess strong adaptability to environmental preservation, a trait that is often lacking in highly artificially selected populations. In the case of the Merino population, a world-renowned fine wool sheep breed, a phenotype with primitive coarse wool characteristic has re-emerged. It is currently unclear whether this characteristic is detrimental to the production of fine wool or whether it is linked to the adaptability of sheep. The underlying genetic/epigenetic mechanisms behind this trait are also poorly understood. RESULTS: This study identified lambs with an ancestral-like coarse (ALC) wool type that emerged during the purebred breeding of Merino fine wool sheep. The presence of this primitive sheep characteristic resulted in better environmental adaptability in lambs, as well as improved fine wool yield in adulthood. Reciprocal cross experiments revealed that the ALC phenotype exhibited maternal genetic characteristics. Transcriptomic SNP analysis indicated that the ALC phenotype was localized to the imprinted Gtl2-miRNAs locus, and a significant correlation was found between the ALC wool type and a newly identified short Interstitial Telomeric Sequences (s-ITSs) at this locus. We further confirmed that a novel 38-nt small RNA transcribed from these s-ITSs, in combination with the previously reported 22-nt small RNAs cluster from the Gtl2-miRNAs locus, synergistically inhibited PI3K/AKT/Metabolic/Oxidative stress and subsequent apoptotic pathways in wool follicle stem cells, resulting in the ALC wool type. The necessity of Gtl2-miRNAs in controlling primary hair follicle morphogenesis, as well as the wool follicle type for ALC wool lambs, was verified using intergenic differentially methylated region-knockout mice. CONCLUSION: The ALC wool type of Merino sheep, which does not reduce wool quality but increases yield and adaptability, is regulated by epigenetic mechanisms in the imprinted Gtl2-miRNAs region on sheep chromosome 18, with the maternally expressed imprinted gene responsible for the ALC phenotype. This study highlights the significance of epigenetic regulation during embryonic and juvenile stages and emphasizes the advantages of early adaptation breeding for maternal parents in enhancing the overall performance of their offspring.

Global DNA Methylation, miRNA, and mRNA Profiles in Sheep Skeletal Muscle Promoted by Hybridization.

With the development of high-throughput sequencing technology, several nongenetic variations, including noncoding RNAs such as miRNAs, and DNA methylation, have been found to play an important role in animal muscle development and fat metabolism. In this study, Southdown and Suffolk were selected as male parents for hybridization with Hu sheep (Southdown × Hu (NH), Suffolk × Hu (SH), and Hu × Hu (HH)). RNA sequencing, bisulfite sequencing, and small-RNA sequencing were used to study the methylation patterns and differences in miRNA and mRNA expression in the F1 sheep longissimus dorsi muscle tissue. We identified 765 differentially expressed genes (DEGs), 10,161 differentially methylated regions (DMRs), and 164 differentially expressed miRNAs, which were significantly enriched in AMPK signaling, fatty acid degradation, metabolism, and other related pathways (P < 0.05). In addition, we constructed a DNA methylation-mRNA and miRNA-mRNA coexpression network. A total of 42 common genes were identified from DMRs and DEGs. Importantly, we predicted that 33 differentially expressed miRNAs directly or indirectly targeted the SLC27A6. The data obtained in this study provide useful information and evidence to support further understanding of the miRNA and DNA methylation of key genes regulating muscle growth and fat metabolism in hybrid sheep populations.