The study investigated the glycolysis pathway mediated by hypoxia-inducible factor-1α (HIF-1α) and the mechanism of its regulation. The results indicated that HIF-1α expression initially increased before subsequently decreasing with aging time during postmortem (p < .01). Glucose transporter-1 (GLUT-1), lactate dehydrogenase (LDH), and hexokinase (HK) displayed a similar trend with aging time (p < .01) while pyruvate dehydrogenase kinase 1 (PDK-1) increased gradually within the first 12 hr before decreasing at 24-120 hr. However, after treatment with a HIF-1α inhibitor, no significant differences were observed in the mitochondrial morphology. Furthermore, lactate content decreased, along with LDH, HK, and F0F1-ATP activities as well as GLUT-1 and PDK-1 expression (p < .01). The shear force for all groups also increased during postmortem aging (p < .01), with that of the controls being significantly higher compared with the treatment groups (p < .01). These findings confirmed that, after slaughter, the hypoxic environment within the muscles provided essential conditions for HIF-1α expression, which, in turn, activated the glycolysis pathway by mediating changes in the activities of glycolytic enzymes and mitochondrial function. Moreover, in accelerating glycolysis rate, the expression of HIF-1α further played a negative role in meat tenderization during postmortem aging. This, it was concluded that HIF-1α expression plays a significant role in postmortem yak meat tenderization by regulating the glycolysis pathway.Pratical applications: While converting muscle into meat through hypoxic glycolysis during postmortem aging is undeniable, the biochemical mechanism of this process mediated remains quite obscure. However, the meat quality difference which impact muscle regulation mechanism during postmortem aging has not been reported. The study investigated the HIF-1α played a major role in both the glycolytic pathway and as well as meat tenderness during the postmortem aging of yak meat. The glycolysis pathway is mediated by hypoxia-inducible factor-1α (HIF-1α), the mechanism of its regulation, and meat tenderness during the postmortem aging of yak meat.

Gut microbiome and heredity are two important factors affecting the intramuscular fat (IMF) of cattle, excluding age, sex, and nutrition. This study aimed at deciphering these two differences by analyzing the gut microbiome and intramuscular differentially expressed genes (DEGs) in the Angus and Chinese Simmental cattle. Feces and longissimus dorsi were collected from the two groups of animals (n = 20/group) for multiomics analysis. Angus holds a significantly higher diversity than Chinese Simmental, and the relative abundance of Roseburia, Prevotella, Coprococcus, etc., was obviously higher in Angus. Chinese Simmental had higher levels of isobutyrate, isovalerate, and valerate, although similar levels of acetate, propionate, and butyrate were observed for the two groups. The DEGs upregulated in Chinese Simmental were mainly involved in immune and inflammatory responses, while those in Angus were associated with the regulation of muscle system and myofibril. We finally identified 17 species, including Eubacterium rectale, etc., which were positively correlated to muscle and fat metabolism genes (MSTN, MYLPF, TNNT3, and FABP3/4) and illustrate the associations between them. Our study unveils the gut microbial differences and significant DEGs as well as their associations between the two breeds, providing valuable guidance for future mechanism research and development of intervention strategies to improve meat quality.

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This study investigated the differences in meat quality during postmortem aging of yak meat from different altitudes as well as the relationship between the release of hypoxic factor HIF‐1α and meat quality. The results showed that the HIF‐1α increased with altitude but during aging process, there was an initial increase before a subsequent decrease (p < .05). Moreover, significant increases were showed in glycolytic potential, a* value, pH, HIF‐1α mRNA expression, HIF‐1α protein expression and shear force with altitude (p < .05). Additionally, the b* value, L* value, water holding power and MFI decreased significantly (p < .05). HIF‐1α was shown, by PLS‐DA method analysis, to be the main protein marker for differences in the quality during aging time of meat from three altitude groups. HIF‐1α protein expression was high correlated with glycolytic potential, pH value, meat color, tenderness and water holding capacity during postmortem aging. The results demonstrated that HIF‐1α is a novel marker protein that influences meat quality in yak from different altitudes and that HIF‐1α‐mediated glycolytic pathway was key to the meat quality during postmortem aging. Practical applications Yak meat has the advantages of high protein, low fat, good amino acid and fatty acid composition, so the nutritional value of yak meat is in line with the current best‐selling beef with less fat in domestic and foreign markets. But consumers often think that the meat tenderness of yak meat is worse than that of beef and improving the quality of yak meat was worthy of attention specifically. This study investigated the differences in meat quality during postmortem aging of yak meat at different altitudes and the relationship between hypoxic factor HIF‐1α release and meat quality.

Metabolic status and gut microecology are implicated in psoriasis. Methotrexate (MTX) is usually the first-line treatment for this disease. However, the relationship between MTX and host metabolic status and the gut microbiota is unclear. This study aimed to characterize the features of blood metabolome and gut microbiome in patients with psoriasis after treatment with MTX. Serum and stool samples were collected from 15 patients with psoriasis. Untargeted liquid chromatography–mass spectrometry and metagenomics sequencing were applied to profile the blood metabolome and gut microbiome, respectively. We found that the response to MTX varied according to metabolomic and metagenomic features at baseline; for example, patients who had high levels of serum nutrient molecular and more enriched gut microbiota had a poor response. After 16 weeks of MTX, we observed a reduction in microbial activity pathways, and patients with a good response showed more microbial activity and less biosynthesis of serum fatty acid. We also found an association between the serum metabolome and the gut microbiome before intervention with MTX. Carbohydrate metabolism, transporter systems, and protein synthesis within microbes were associated with host metabolic clusters of lipids, benzenoids, and organic acids. These findings suggest that the metabolic status of the blood and the gut microbiome is involved in the effectiveness of MTX in psoriasis, and that inhibition of symbiotic intestinal microbiota may be one of the mechanisms of action of MTX. Prospective studies in larger sample sizes are needed to confirm these findings.