Lycopene β-cyclase (LCYB) is a key enzyme that catalyzed lycopene in carotenoid biosynthesis pathway. Osmanthus fragrans is mainly distributed in the south of China. O. fragrans, which bloom in late autumn and winter will show a phenomenon of deepening color when faced with low temperatures. In this study, it was found that the petal color of O. fragrans became darker, the carotenoid content increased significantly, and the expression of key synthetic gene OfLCYB was up-regulated by relatively low temperature treatment. To study the mechanism of OfLCYB accumulation and response to carotenoids, in this study, OfLCYB gene (GenBank No. PP438593) was cloned from O. fragrans petals, and overexpression vector was constructed to transform tobacco (Nicotiana tabacum). The results showed that, overexpression of OfLCYB could promote the accumulation of carotenoids in the leaves of transgenic tobacco, and promote the expression of related genes involved in carotenoid biosynthesis pathway. After low temperature treatment (4 ℃), tobacco leaves with OfLCYB overexpression showed better low temperature tolerance compared with control plants.Under low temperature treatment, relative electrolyte leakage (REL) and malondialdehyde (MDA) contents in leaves of transgenic plants were significantly lower than those of control plants. The activity of Superoxide dismutase (SOD), peroxidase (POD), catalase (CAT) and proline content were significantly increased. In addition, compared with control plants, the expression levels of 2 cold response transcription factors NtDREB1 (dehydration responsive element binding 1) and NtDREB3, and 2 cold induction genes NtERD10A (early responsive to dehydration 10A) and NtERD10B in transgenic tobacco leaves were up-regulated. According to the results, it was speculated that OfLCYB might enhance plant low temperature tolerance by promoting carotenoid synthesis. This study provides an reference for improving cold tolerance of O. fragrans and expanding its cultivation area.

The adenosine 5'-phosphosulfate reductase (APR) is a critical enzyme in the plant sulfate assimilation pathway, playing a vital role in sulfate metabolism and sulfur cycling. This protein comprises 2 conserved domains: PAPS_reductase and Thioredoxin, primarily exerting its catalytic function in the plastids, significantly impacting plant growth, development, and stress responses. To systematically investigate the structural and functional characteristics of the APR gene family in Brassica napus (oilseed rape), this study used 3 APR protein sequences from Arabidopsis thaliana as templates to perform homology analysis across the entire genome of B. napus. A total of 10 APR family genes were identified, distributed across 9 chromosomes. Further identification and analysis of the gene family were carried out and preliminary exploration of the expression response patterns of APR genes in B. napus under abiotic stress conditions was also initiated. The results revealed that the amino acid sequence lengths of B. napus APR proteins ranged from 219 to 468 residues, with molecular weights spanning from 24.29 to 51.69 kD, and isoelectric points varying between 5.43 and 8.84. Phylogenetic analysis classified the B. napus APR genes into 3 subclades, each containing members with similar exon-intron structures. All APR proteins were confirmed to possess the conserved PAPS_reductase and Thioredoxin domains. Collinearity analysis indicated that segmental duplication played a predominant role in the expansion of the B. napus APR gene family. Expression profiling showed that APR genes exhibited spatiotemporal expression specificity in various tissues at different developmental stages, with notably higher expression levels in cotyledons, rosette leaves, and silique pericarps. Analysis of cis-regulatory elements in promoters and expression patterns under abiotic stress conditions revealed that the promoter regions of B. napus APR genes were enriched with cis-elements associated with hormone response and stress adaptation. Furthermore, the expression of these genes was induced by heavy metal cadmium and lead stress, as well as sulfur deficiency stress. These findings suggest that APR genes in B. napus play significant roles in responding to cadmium and lead heavy metal stresses, providing reference for further investigation into the molecular functions of the APR gene family in B. napus.

As the planting years of pitaya (Hylocereus undatus) increase, phenolic acid metabolites gradually accumulate in the soil, promoting the colonization of pathogenic bacteria, fungi, and nematodes, eventually causing continuous cropping obstacles. In this study, culturable bacteria were isolated from the rhizosphere soil of pitaya continuously cultivated for 6 years and 3 years using pure culture technique, and species identification was conducted through 16S rRNA gene sequencing. At the same time, soil enzyme activity assays were conducted to investigate changes in enzyme activity in pitaya soil over different planting durations, high performance liquid chromatography (HPLC) was utilized to identify and quantify the types and contents of phenolic acid metabolites in the soil, and the response characteristics of soil bacteria and enzyme activity to phenolic acid metabolites were analyzed. The results indicated that continuous cropping increased the diversity of bacterial communities in pitaya soil, a total of 112 strains, including 4 phyla, 5 classes, 10 orders, 16 families, 21 genera, 56 species, were isolated from the rhizosphere soil, among which the relative abundance of biocontrol bacteria such as Pseudomonas, Burkholderia, and Bacillus decreased by 23.36%. In continuous cropping pitaya soil, catalase and cellulase activities decreased, whereas urease and sucrase activities increased, and the levels of gallic acid, ferulic acid, salicylic acid, and benzoic acid increased by 163.80%, 194.92%, 341.57% and 175.93%, respectively. Response relationship analysis showed that there was a certain correlation between phenolic acids and microbial community structure. The above results demonstrated that continuous cropping led to the accumulation of phenolic acids, including gallic acid, ferulic acid, salicylic acid, and benzoic acid, then caused an imbalance in the soil microbial community structure, a reduction in beneficial microorganisms, changes in soil enzyme activity, impaired nutrient absorption by plants, and ultimately resulted in continuous cropping obstacles. This study provides basic data for the subsequent development of microbial agents with phenolic acid degradation function and field management techniques for pitaya.

Alternative splicing (AS) is a post transcriptional modificaption process, and plays important roles in various physiological processes of living organisms. TCP family is a kind of plant specific transcription factor that participates in various growth and development regulatory processes. In order to further explore the expression characteristics and biological function of 2 alternative splice variants of TCP19b gene in moso bamboo (Phyllostachys edulis), RT-PCR was used to clone the full-length CDS of TCP19b from moso bamboo, qRT-PCR and GUS tissue staining were used to analyze the expression level and expression site of the alternative splice variants. The localization and function of alternative splice variants were analyzed by subcellular localization and genetic transformation. The results showed that PheTCP19b gene generated 2 alternative splice variants, PheTCP19bα and PheTCP19bβ, encoding 346 and 382 amino acid, respectively, which contained conserved bHLH domains. The PheTCP19b gene was closely related to rice (Oryza sativa) OsTCP19. There were some differences in tissue-specific expression patterns between the 2 alternative splice variants. The PheTCP19bα had obvious tissue specificity, while PheTCP19bβ showed constitutive expression pattern. Brassinolide (BR) could induce the expression of 2 alternative splice variants. The 2 alternative splice variants proteins were enriched in the nucleus. Both PheTCP19bα and PheTCP19bβ could complement the multi-branching phenotype of Arabidopsis thaliana brc1 mutant to wild type phenotype. The study provides foundation for further study on the mechanism of PheTCP19b alternative splice variants in bud development.

1-aminocyclopropane-1-carboxylate oxidase (ACO) is one of the key rate limiting enzymes in the ethylene synthesis process. In this study, genome-wide identification and expression analysis of the PeACO gene family were performed in order to investigate the effects of PeACOs on the lignification process of moso bamboo (Phyllostachys edulis) stalks. In this study, 11 sequences of PeACOs with complete 2OG-FeII_Oxy structural domains were identified in the moso bamboo genome by sequence comparison with ACO genes in rice (Oryza sativa); Physicochemical analysis of the proteins showed that these genes encoded 304~445 amino acids, and the molecular weights of the proteins ranged from 34 105.83 to 49 417.78 D, evolutionary relationship and gene structure analyses showed that pairs of genes in the same branch were highly conserved at the gene structure and protein levels. The collinearity analysis showed that ACO gene family had 6 co-linear gene pairs in moso bamboo, and suggested that genome replication events had an important effect on the expansion of the number of PeACOs genes. PeACOs were expressed in all tissues of moso bamboo, and the highest abundance was especially found in shoots during the rapid growth period. The removal of bamboo clum sheath during the rapid growth period led to the deepening of lignification of the culm. And the expression analysis showed that most PeACOs genes were significantly upregulated by the removal of bamboo sheaths, and indicated that these genes played an important role in this process, and the gene pairs with similar structures have similar expression patterns. This study provides theoretical basis for further study on the function of ACO gene family of bamboo.

Camellia taliensis is an important wild relative species of tea and an important part of tea resources. It is very important to study the genetic diversity and genetic relationship of Camellia taliensis population for better scientific protection and rational utilization of Camellia taliensis germplasm resources. Using the SSR marker technology, the genetic diversity and genetic relation-ships of 45 Camellia taliensis variations and 5 Camellia sinensis var. assamica varieties in 5 cities in the Lancang River Basin were determined and evaluated. The results showed that a total of 55 polymorphic sites were detected by 15 pairs of effective primers, with an average of 3.67 sites amplified by each pair of primers. The average expected heterozygosity (He) of Camellia taliensis resources was 0.346. The polymorphism information content (PIC) ranged from 0.024~0.661, with an average of 0.381. Shannon index ranged from 0.067~1.321, with an average of 0.669. The proportion of polymorphic primers was 60.0%, and the proportion of polymorphic primers to effective primers was 75.0%. The results of cluster analysis showed that the classification of C. taliensis germplasm in the Lancang River Basin was correlated with geographical regions. The genetic distance between C. taliensis populations with distant geographical locations was far, but the genetic distance within populations was close.The findings demonstrated the C. taliensis resources in the Lancang River Basin have moderate genetic diversity with moderate richness. This study offers a theoretical foundation for the establishment and preservation of C. taliensis germplasm resources as well as the creation of a genetic map.

The quality of Coffea arabica beans is the primary objective of breeding new varieties of C. arabica with high quality, among these, the aroma of coffee bean is the key factor to evaluate the quality of C. arabica bean, and fatty acid is one of the precursors to form volatile aroma components of C. arabica bean. Stearoyl-ACP desaturase (FAB) is an essential enzyme involved in unsaturated fatty acid synthesis in plants, and its desaturation function significantly influences the proportion and unsaturation level of fatty acids. Through Blast comparison analysis, 4 members of the CaFAB2 gene family within the C. arabica genome were identified in this study. Further investigation illuminated that these 4 CaFAB2 genes consisted of 381~415 amino acids with molecular weights ranging from 43 936.6 to 47 693.4 D. Besides, these 4 genes also had isoelectric points greater than 7 and exhibited hydrophilic characteristics with instability indices from 29.55 to 42.67 but less than 100 fat index values. And the total average coefficients were all negative, so they were hydrophilic proteins. The proteins of 4 CaFAB2 genes were localized in chloroplasts. Through gene family analysis, it was found that the conserved motif of the CaFAB2 gene family was identical to that of the FAB2 gene family of Arabidopsis thaliana, and the distribution position was highly similar, with the domain PLN00179. Additionally, it was observed that 2 offspring genes corresponded to 1 parental gene between C. eugenoedes and Coffea canephora regarding the presence of CaFAB2 genes in the genome structure of C. arabica. Furthermore, the fatty acid contents were mainly composed of linoleic acid, palmitic acid, oleic acid, and stearic acid during 4 developmental stages of C. arabica seeds, and these 4 compounds indicated the same trend characterized by initial decrease followed by gradual increase. The transcriptome sequencing and real-time fluorescence quantitative PCR analyse revealed a positive correlation between CaFAB2.3 and oleic acid synthesis, while the CaFAB2.1 and CaFAB2.3 primarily participated in early palmitic acid synthesis in the 4 developmental stages of C. arabica seeds. This study provides a theoretical foundation for further investigation on variation tendency and biosynthesis of fatty acids in C. arabica, and offered novel insights into the identification and regulatory mechanisms of CaFAB2 genes in C. arabica.

As one of the most important domestic animals, the origin and spread pattern of taurine cattle (Bos taurus) in China has received widespread attention. In this study, 9 cattle remains from 3 archaeological sites in the middle reaches of the Yellow River were collected for extraction of ancient DNA for PCR sequencing and phylogenetic analysis to explore the origin and spread of taurine cattle in China. Through multiple rounds of PCR experiments, 527 bp endogenous mitochondrial DNA (mtDNA) sequences were obtained from 4 cattle remains from Taosi site (4300~4100 before the present). The results of haplotype classification clearly showed that all samples from the Taosi site were divided into 4 haplotypes, all of which belonged to domesticated taurine cattle T3 and T4 haplogroups which supported that Taosi domestic cattle originated from the Near East and were already utilized by people living in North China 4 100 years ago. Additionally, the abundant number of haplotypes at the Taosi site suggested that the ancient cattle population at the Taosi site had high maternal genetic diversity. Population pairwise F_ST distance analysis and the Median-Joining network analysis indicated that the ancient cattle had a close genetic relationship with the modern East Asian taurine cattle (F_ST=0.0164) and Chinese taurine cattle (F_ST=0.0066), suggesting that the ancient cattle population at Taosi site might be one of the maternal origin for the modern East Asian and Chinese taurine cattle. This study provides more molecular genetic evidence for resolving the origin and spread of cattle in China.

Proline hydroxylase 2 (PHD2) and angiopoietin 1 (Ang-1) play an important role in animal adaptation to hypoxia and angiogenesis. In order to study the expression and distribution of PHD2 and Ang-1 in the lungs of yaks (Bos mutus) of different ages, and to explore its role in the formation of hypoxic adaptive structure in the lungs of yaks. In this study, 3-day-old, 6-month-old, 3-year-old and 6-year-old yaks were used as research objects, and adult cattle (B. taurus) were selected as normoxic control. Immunohistochemical (IHC) staining, tissue immuno-fluorescence (IF) staining, qRT-PCR and Western blot were used to study the expression of PHD2 and Ang-1 in lung tissues of yaks and cattle of different ages. The results of IHC and IF showed that the expression sites of PHD2 and Ang-1 in yak and cattle were basically the same, mainly distributed in tracheal epithelial cells, tracheal glands, pulm-onary artery endothelial cells and alveolar epithelial cells. The results of qRT-PCR showed that the relative expression of PHD2 in yak group was significantly higher than that in cattle group, and that in 3-day-old yak group was significantly higher than that in other age groups (P<0.01). The relative expression of Ang-1 in yak group was significantly higher than that in cattle group, and that in 6-year-old yak group was significantly higher than that in other age groups (P<0.01). Western blot results showed that the relative expression of PHD2 protein in yak group was significantly higher than that in cattle group. With the increase of yak age, the relative expression of PHD2 protein decreased gradually. The relative expression of Ang-1 protein in the yak group was significantly higher than that in the cattle group, and the relative expression of Ang-1 protein gradually increased with the increase of yak age. In summary, PHD2 and Ang-1 play an important role in the adaptation of yak lungs to high altitude hypoxic environment. Both of them mainly act on lung epithelial cells and vascular endothelial cells, thereby maintaining the stability of normal breathing and pulmonary vascular function of yak lungs under hypoxic conditions. This study provides some basic data for further exploring the mechanism of hypoxia adaptability of yak lung in plateau environment.

As a key element of trace elements, iron is of great significance to the growth of animals, and iron deficiency will lead to a variety of negative effects such as developmental disorders, poor reproductive performance, anemia and diarrhea. In this study, lactating sows (Sus scrofa domestica) from 7 d before farrowing to 21 d after farrowing were taken as the research object to investigate the effect of Iron preparations for blood added to feed on the production performance, physiological and biochemical indexes of lactating sows and piglet-related indicators. The results showed that compared with the blank control group, continuous feeding for 28 d after adding Iron preparations for blood at a dose of 1 kg/t of feed could effectively reduce the farrowing rate of sows, increase the mating rate, improve the labor process of sows, increase the litter weight of piglets, the average weight of piglets, the weight of the weaning litter, reduce the diarrhea rate, malformation rate and stillbirth rate of piglets, thereby improving the production performance of sows and growth performance of piglets. This study provides a reference and basis for the clinical application of Iron preparations for blood in veterinary medicine to improve the production performance of sows.

Acyl-CoA synthetase long chain family member 6 (ACSL6), a key enzyme in the uptake and transport of free fatty acids, is involved in the regulation of fatty acid metabolism during lactation in dairy animals. This study aimed to preliminarily investigate the transcriptional regulation mechanism of ACSL6 gene (Gene ID: XM_018050725.1) through promoter cloning, bioinformatics analysis and diluciferase activity detection in dairy goats (Capra hircus). The full-length sequence of the ACSL6 promoter was obtained by PCR amplification using the blood genomic DNA of Xinong Saanen dairy goats as a template. The sequence features of the binding sites and promoter regions with high prediction scores were screened using bioinformatics analysis software. The promoter deletion fragment vectors were cloned and constructed, which were co-transfected with the internal reference vectors into the mammary epithelial cells of dairy goats, and the promoter active regions were identified by dual luciferase activity assay. The results showed that the full-length sequence of the ACSL6 promoter was 2 108 bp. The multiple transcription factor binding sites were existed in the ACSL6 promoter. The two CpG islands with lengths of 101 and 460 bp were identified in the promoter sequences of -907~-807 bp and -513~-54 bp, respectively. The nine deletions obtained from the cloning were analysed by dual-luciferase activity, and it was found that the core region of the ACSL6 promoter was located at -170~-33 bp, and there might be negative regulatory elements upstream of the transcriptional start site at -2 004~-1 707 bp, -1 334~-957 bp, and -584~-271 bp. This study provides basic information to reveal the molecular mechanism of ACSL6 regulating milk fat metabolism in dairy goats, and provides a reference to improve the quality of goat milk at the molecular level.

Highly intensive breeding of mutton sheep (Ovis aries) can easily lead to oxidative stress, reduce body resistance, disturb gastrointestinal flora, and affect growth performance. Dietary bacterial enzyme compound preparation can improve intestinal flora structure, nutrient digestibility and animal growth performance. This study aimed to investigate the effects of bacterial enzyme compound preparation on growth performance, serum indexes and fecal microorganisms of Hu sheep. A total of 48 male Hu lambs ((18.00±2.00) kg) aged 2 months were randomly assigned into 4 groups. Lambs in Group C (control) were fed a basal diet, and the other 3 groups were fed a basal diet with 0.1% (Group 1), 0.2% (Group 2) and 0.3% (Group 3) bacterial enzyme preparation, respectively. The feeding included a pre-experiment for 7 d and a formal experiment for 60 d. Results showed that, compared with Group C, average daily gain (ADG) in Group 1 and Group 2 increased significantly (P<0.05), and the feed to gain ratio (F/G) significantly decreased in all groups (P<0.05) during 31~60 d and 1~60 d; serum albumin ( ALB) and glucose (GLU) content in all groups and high density lipoprotein in Group 1 increased significantly (P<0.05); serum activity of superoxidized dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) increased significantly in all groups (P<0.05); serum immunoglobulin (Ig) IgA and IgG increased significantly in all groups (P<0.05), and serum IgM increased significantly in Group 3 (P<0.05); the apparent digestibility of neutral detergent fibre (NDF) and acid detergent fibre (ADF) in Group 2 significantly increased (P<0.05). At phylum level, the abundance of Verrucomicrobiota increased significantly (P<0.05), while Cyanobacteria and Campylobacterota decreased significantly (P<0.05). At genus level, the abundances of Alistipes and Prevotellaceae_UCG-001 significantly increased (P<0.05), while Candidatus_Saccharimonas significantly decreased (P<0.05). In conclusion, the bacterial enzyme compound preparation could improve the growth performance, antioxidant and immune capacity, improve nutrient apparent digestibility, promote the colonization of beneficial bacteria, inhibit the colonization of harmful bacteria. The addition effect of 0.2% bacterial enzyme compound preparation was the best. This study provides a scientific basis for the application of bacterial enzyme compound preparation in the production of Hu sheep.

Diquat, a bipyridine herbicide commonly utilized in modern agricultural production, can easily induce oxidative stress in poultry, in order to investigated the effects of oxidative stress induced by Diquat on hens' oviduct magnum, in this study, 45 healthy 180-day-old Kangle yellow hens (Gallus gallus) with similar body weight were randomly divided into 3 groups, with 15 hens in each group. The hens in each group were fed a basal diet and had free access to water. After 1 week of adaptive feeding, the experimental groups were injected with 10 and 20 mg/kg BW (body weight) dose of Diquat intraperitoneally, while those in control group were injected with an equal dose of normal saline intraperitoneally. After 21 d, the oviduct magnum tissues were collected. The antioxidant indicators were detected using Antioxidant Function Assay Kit. The pathological injury was observed using hematoxylin-eosin (HE) staining technology, and the relevant protein distribution were detected by immunohistochemistry (IHC) technology. The expressions of apoptosis and reproductive performance-related genes and proteins were detected using qPCR and Western blot technology. The results showed that the activities of catalase (CAT) and total superoxide dismutase (T-SOD) in the oviduct magnum of Diquat groups were significantly decreased (P<0.05), and the concentration of malondialdehyde (MDA) was significantly increased (P<0.05). HE staining results showed that the tube diameter of oviduct magnum in Diquat groups were reduced, cells of lamina propria were sparsely-distributed, cilia in the free surface of epithelium mucosae were damaged, and mucosal epithelial cells were vacuolated in Diquat 20 mg/kg group. IHC results showed that the staining intensity of proliferating cell nuclear antigen (PCNA) in the epithelium mucosae and lamina propria of oviduct magnum in Diquat groups were decreased. The staining intensity of Wingless-related murine mammary tumor virus integration site 4 (Wnt4) in the free surface of mucosal epithelium was also decreased. qPCR results showed that the gene expression level of anti-apoptosis-related gene B-cell lymphoma-2 (Bcl-2) in oviduct magnum tissues of Diquat 20 mg/kg group was significantly decreased (P<0.05). The gene expression levels of Bcl-2 associated X protein (Bax) and cysteinyl aspartate specific proteinases 3 (Caspase3) and the ratio of Bax/Bcl-2 in Diquat groups were significantly up-regulated (P<0.05). The gene expression levels of reproductive performance-related genes zona pellucida sperm-binding protein 2 (ZP2) and Wnt4 were significantly down-regulated (P<0.05). Western blot results showed that the protein expression levels of Bcl-2, Bax, Caspase3, ZP2 and Wnt4 were basically consistent with the gene expression changes. The above results indicated that Diquat can induce oxidative stress and apoptosis in the oviduct magnum of hens, thereby damaging the tissue structure of the enlarged part and inhibiting the expression of genes related to reproductive performance of the oviduct magnum. This study provides a theoretical basis for alleviating the damage to the oviduct of poultry caused by the bipyridine pesticides and protecting the reproductive performance.

The functional studies of miR-1306-5p are mostly found to affect the proliferation of smooth muscle cells and various tumor cells. In the early stage, the research group collected the pectoral muscles of rose-crowned chickens (Gallus gallus) and Kebao chickens on the 8th day of embryonic stage for high-throughput sequencing. In this study, differentially expressed miR-1306-5p was selected from the previous sequencing data. The aim was to investigate the function of miR-1306-5p in the proliferation and differentiation of chicken preadipocytes. Using Targetscan and miRanda software predicted target genes of miR-1306-5p. Select the target gene related to fat, bone morphogenetic protein 2 (BMP2), and design the wild type and mutant vector of the target gene BMP2. The vector and miR-1306-5p mimics were constructed to co-transfect chicken fibroblasts, and the target relationship between them was verified by luciferase reporter gene detection system. miR-1306-5p mimics and inhibitors were transfected into chicken preadipocytes, respectively. Cell proliferation capacity was detected by Cell Counting Kit-8 (CCK-8) kits. The differentiation induced by oleic acid was detected by oil red O staining. The results showed that the luciferase activity in the BMP2 wild type co-transfected with miR-1306-5p mimics group was extremely significantly decreased compared with the negative control group (P<0.01), while the mutant type had no significant change. After transfection with miR-1306-5p mimics for 48, 72 and 96 h, the proliferation capacity of chicken preadipocytes was extremely significantly lower than that of the negative control group (P<0.01). The gene expression of fatty acid binding protein 4 (FABP4) was extremely significantly increased during oleic acid-induced differentiation of chicken preadipocytes (P<0.01). The gene expressions of endogenous miR-1306-5p and BMP2 were extremely significantly decreased at 48 and 72 h after induction of differentiation (P<0.01). Lipid droplets were smaller after transfection of miR-1306-5p mimics and increased after transfection of miR-1306-5p inhibitor in chicken preadipocytes. Therefore, miR-1306-5p may inhibit the proliferation and differentiation of chicken preadipocytes by targeting BMP2. This study provides basic data for further exploring the mechanism of miR-1306-5p in chicken preadipocyte differentiation.

Rainbow trout (Oncorhynchus mykiss) is extremely sensitive to hypoxia, and its antioxidant capacity and apoptosis are affected by hypoxia environments. To understand the effects of hypoxia stress on the heart of rainbow trout, antioxidant and apoptotic gene expression were measured using enzyme activity assay and qRT-PCR during moderate hypoxia (4.5±0.1 mg/L) and severe hypoxia (3.0±0.1 mg/L) stress for 4, 8, 12, 24 h, 1 month, and reoxygenation (8.5±0.1 mg/L) for 12 and 24 h. The results showed that total superoxide dismutase (T-SOD) and catalases (CAT) activities were significantly reduced at 24 h and 1 month, malondialdehyde (MDA) content was significantly increased at 12 h (P<0.05) under severe hypoxia stress; T-SOD, CAT and total antioxidant capacity (T-AOC) activities were gradually increased under moderate hypoxia stress. Compared with the control group, total protein (TP) content was significantly decreased after 1 month of hypoxia stress (P<0.05). The expression of antioxidant-related genes Cu/Zn-SOD (cu/zn-sod) and Mn-SOD (mn-sod) were significantly decreased under severe hypoxia and moderate hypoxia stress compared with the control group (P<0.05); the expression of cat was significantly decreased at 4, 8 and 12 h under severe hypoxia (P<0.05). After severe hypoxia stress, the expression of apoptosis-related gene B-cell lymphoma-2 (Bcl-2) increased significantly under short-term hypoxia stress compared with the control group, while the expression of Bcl-2-associated X (Bax) showed no significant difference, and the expression of caspase-3 (casp3) and tumor suppressor gene 53 (p53) decreased significantly at 12 h (P<0.05). Acid phosphatase (ACP) and alkaline phosphatase (AKP) were significantly higher than those of the control group at 12 h under severe hypoxia stress and moderate hypoxia stress (P<0.05). The above results suggested that rainbow trout heart could reduce oxidative damage by regulating the activities of antioxidant enzymes and the expression of apoptosis-related genes under different concentrations of hypoxia. This study provides a theoretical basis for further elucidating the oxidative stress mechanism in rainbow trout heart under hypoxia stress.

Butenyl-spinosyn, a secondary metabolite produced by fermentation of Saccharopolyspora pogona, is a green bio-insecticide. However, due to the low yield of fermentation and can not meet the needs of industrial production, the breeding of strains with high production performance of butenyl-spinosyn is the key to realize industrial production. In this study, ribosomal protein S12 (RpsL) and RpsL mutant gene overexpression engineering strains Q8 (rpsl)、W43 (rpsl^K88R)、W44 (rpsl^R86P)、W45 (rpsl^K88E)和W46 (rpsl^K43N) were constructed were constructed using Saccharopolyspora pogona as the base cells. The effect of RpsL on the synthesis of butenyl-spinosyn was studied by shaking flask fermentation and comparison of RpsL protein structure. The results showed that the engineered strains Q8, W43, W44, W45, W46 increased the yield of butenyl-spinosyn to 275%, 146%, 111%, 122% and reduced to 75%, respectively. The overexpression of rpsl and rpsl^K88R genes increased the transcription level of the synthetic pathway genes, and thus significantly increased the yield of butenyl-spinosyn. At the same time, homologous modeling of the two was conducted, and it was found that RpsL^K88R mutant structure had a larger deflection of the side chain compared with RpsL, which affected the binding effect to mRNA and thus reduced the ribosome translation efficiency, so its yield extraction effect was slightly lower than RpsL. This study provides a reference for protein engineering RpsL to improve the yield of butenyl-spinosyn.

Bovine viral diarrhea virus (BVDV) is one of the main pathogens causing viral diarrhea of calves(Bos sp.), which leads to decreased immunity and increase of morbidity and mortality. At present, the commonly used detection methods for BVDV have low sensitivity and are prone to false positives, This research is based on droplet digital PCR (ddPCR) technology to establish the accurate detection technology of BVDV. Firstly, primers and probes were designed for the BVDV 5' UTR gene conserved sequence region, and the BVDV 5' UTR gene was synthesized and the plasmid standard was constructed. Real-time quantitative PCR (qPCR) and ddPCR methods were established using BVDV plasmid standards, and the reaction parameters and conditions were optimized to analyze their sensitivity, specificity and repeatability, and the clinical application was carried out. The results showed that the optimal primers and probe concentrations were 300 and 500 nmol/L, respectively. The standard curve showed a good linear relationship, and the minimum detection limit was 1 × 10⁴ copies/μL, with good specificity and repeatability. The minimum detection limit of ddPCR was 0.64 copies/μL, and the sensitivity of ddPCR was 15 625 times higher than that of qPCR. The method had good specificity and repeatability. The detection rate of ddPCR and qPCR was 15.58% and 14.63% respectively in 82 samples. The ddPCR method established in this study was more sensitive, efficient, specific and reproducible than the qPCR method, which provides technical support for the differential diagnosis of BVDV.

In teleosts fish, some species have significant differences in breeding benefits due to male and female dimorphism. In order to improve the efficiency of aquaculture, monoculture is one of the goals of these fish breeding. Sex reversal, as one of the effective means to achieve unisexual breeding through sex-controlled breeding, has always been a hot topic in teleosts fish reproduction and breeding research. In this paper, the known teleosts fish natural sex reversal phenomenon, sex reversal method, sex reversal mechanism and current application in teleosts fish breeding are described, which provides a theoretical reference for molecular breeding for new varieties of high quality and accelerating the improvement of fish breeding efficiency.

Myostatin (MSTN) is a negative regulator of skeletal muscle growth and development, and mutations in the MSTN gene can promote muscle development in animals. Currently, Sanger sequencing technology is the classic method for detecting MSTN gene mutations, but this method has the disadvantages of low detection throughput, low visualisation of mutation information and high detection cost. In this study, MSTN gene mutations in 96 cattle (Bos taurus) could be detected at one time by using next-generation sequencing technology with a specific Barcode sequence designed. In addition, based on the Barcode sequences in the sequencing Fastq result files, the related data analysis DAVID (detect and visualize insertion-deletion) software was developed using asynchronous threading and concurrent algorithms. Using DAVID software, the sequencing data of 96 mixed samples were split one by one and compared with amplicon sequence, and finally the graphical and statistical information of MSTN gene mutation was obtained. Using DAVID technology, 96 Mongolian cattle were examined, and found that 1 head of cattle was heterozygous for 11 bp deletion of the MSTN gene, and the remaining 95 head of cattle were wild-type, and the 11 bp heterozygous deletion was further verified by Sanger sequencing. This study constructed a high-throughput technical system for detecting bovine MSTN gene mutations, and provides technical support for genetic improvement and breeding of cattle.

Trypanosomosis (Surra) by Trypanosoma evansi, which resides in the blood, is a protozoan disease in animals such as horses (Equus) and camels (Camelus). Accurate diagnosis is a crucial step in the effective prevention and control of Surra, but the existing diagnostic techniques have many drawbacks such as high false negative rates and high prices. Based on recombinant expression of nucleoside triphosphate diphosphate hydrolase (TeNTPDase) from T. evansi, in this study, an ELISA method was established for Surra by optimizing various reaction parameters, including antigen coating concentration and conditions, serum dilution and incubation conditions, conjugated second antibody dilution and incubation conditions, and evaluated its diagnostic efficacy. The results showed that the recombinant TeNTPDase was mainly expressed in the form of inclusion bodies, with a size of approximately 60 kD. The coefficient of variation of the established ELISA method in different batches of coating antigens were 3.50%~7.32% being less than 10%, and the coefficient of variation at different incubation time points at 37 ℃ were 3.89%~14.45% being less than 15%, indicating good repeatability and stability. Moreover, when using the established ELISA method to detect clinical serum samples of horses, it was found that the positive rate of Surra was 5.83% (7/120), slightly higher than that of the commercial test kit (3.33%), but the difference was not significant, with a coincidence rate of 92.5% (111/120). This study provides technical support for the effective prevention and control of Surra in horses.

Ferritin nanoparticles are widely used in vaccine research due to their surface that can display multiple antigens, which can better promote cell uptake and antigen presentation, and thereby enhance immune efficacy. This study developed ferritin-based nanoparticles carrying the African swine fever virus (ASFV) p34 protein and evaluated its immunogenicity, aiming to provide an reference for the research on nanoparticle vaccines against ASFV. Initially, the gene sequences encoding the p34 protein and Spytag (ST) were cascaded and inserted into the pET-28a(+) vector to create the pET-p34-ST recombinant plasmid. The gene sequences encoding Spycatcher (SC) and ferritin (F) were cascaded and then inserted into the pET-28a(+) vector to produce the pET-SC-F recombinant plasmid. Both plasmids were expressed in Escherichia coli upon induction. Subsequently, after purifying the 2 recombinant proteins p34-ST and SC-F by affinity chromatography, they were conjugated in vitro to obtain the recombinant nanoparticle F-p34. The F-p34 was identified and morphologically characterized by SDS-PAGE, Western blot, dynamic light scattering (DLS) and transmission electron microscopy (TEM), and finally, the immunogenicity was evaluated by immunizing BALB/c mice (Mus musculus). The results showed that in this study, the prokaryotic expression vectors pET-28a-p34-ST and pET-28a-SC-F were successfully designed and constructed. Through expression, purification and coupling in vitro, recombinant nanoparticle F-p34, which was conjugated with ASFV p34 protein, was successfully prepared, and it could specifically react with ASFV positive serum. In vitro the characterization by DLS and TEM showed that the particle size of F-p34 was approximately 21 nm, and it had a uniform nanoparticle structure. After immunizing mice with F-p34, a specific immune response could be elicited in the body within 7 d. The antibody titer reached the highest level at 42 d and was significantly higher than that of the p34 immunization group (P<0.05). The proliferation level of spleen lymphocytes in the F-p34 immunization group and the secretion levels of cytokines interleukin 4 (IL-4), IL-10, IL-2 and interferon (IFN-γ) in serum were significantly higher than those in the p34 immunization group (P<0.05). In conclusion, this research successfully prepared nanoparticle antigen carrying the ASFV p34 protein with good immunogenicity, expanding the research perspectives of subunit vaccines for African swine fever.