Wei Yang

The purpose of this study is to investigate the effects of sex on the nutritional metabolism of domestic cats. Twelve healthy 1-year-old Chinese domestic cats (equal numbers of males and females) were randomly assigned to a female group (F group) and a male group (M group). They were fed the same diet for a 30-day experimental period. This study involved measuring growth performance, apparent total tract digestibility of nutrients, and Serum biochemical indices, combined with a comprehensive analysis using high-throughput 16S rRNA sequencing of feces and untargeted metabolomics in serum (LC-MS). The results showed that the average daily feed intake and apparent digestibility of crude fiber in Group M were significantly higher than those in Group F (p < 0.05), whereas serum alanine aminotransferase activity in Group F was significantly higher than that in Group M (p < 0.05). Regarding gut microbiota, the Alpha diversity indices (Chao1, Faith, Shannon, Simpson) in Group F were all significantly higher than those in Group M, and Beta diversity showed a highly significant separation (p < 0.01). LEfSe analysis revealed that Group F was characterized by the bacterial genera Blautia A and Faecalimonas, while Group M was characterized by Bifidobacterium. Serum metabolomics identified a total of 125 candidate metabolites meeting exploratory screening criteria (VIP > 1, p < 0.05); L-histidine was significantly upregulated in Group F compared to Group M; while L-cysteine, -tocopherol, γ-glutamylfelinylglycine and 6-phosphogluconate were significantly upregulated in Group M compared to Group F. These metabolites were primarily enriched in pathways related to linoleic acid metabolism, arachidonic acid metabolism, taurine and hypotaurine metabolism, and histidine metabolism. Combined analysis indicated that the genus Bifidobacterium showed significant positive correlations with L-cysteine, gamma-glutamylfelinylglycine, α-tocopherol, 6-phosphogluconate, and felinine; and significant negative correlations with L-histidine. In summary, Nutritional metabolic efficiency in cats is related to sex-regulated gut microbiota and metabolic pathways, The findings of this study provide preliminary evidence for the development of precision nutritional formulations tailored to cats of different sex.

Background: Plant essential oils are extensively utilized for their antimicrobial properties; however, the specific antifungal mechanisms of certain compounds are not well characterized. Geraniol, a naturally occurring monoterpene alcohol approved for use in foods, demonstrates potential efficacy against spoilage fungi, yet detailed mechanistic insights are lacking. Methods: In this study, we determined the minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) of geraniol against P. polonicum. We assessed the underlying mechanisms by evaluating membrane integrity, intracellular leakage, reactive oxygen species (ROS), antioxidant enzymes (superoxide dismutase [SOD], peroxidase [POD], catalase [CAT]), malondialdehyde (MDA) levels, ATP content, and ATPase activity. Inoculated yam slices were exposed to geraniol vapor, and we monitored sensory, physicochemical, enzymatic, and microbial parameters. Results: Geraniol exhibited a minimum inhibitory concentration/minimum fungicidal concentration (MIC/MFC) of 0.3 mL/L. It disrupted cellular membranes, induced leakage, generated ROS, and caused lipid peroxidation, leading to elevated levels of malondialdehyde (MDA). Additionally, geraniol activated antioxidant enzymes and impaired energy metabolism. Fumigation with geraniol dose-dependently delayed the deterioration of yam, reduced weight loss, preserved texture and color, inhibited polyphenol oxidase (PPO) and POD activities, enhanced CAT and SOD activities, lowered MDA levels, and suppressed bacterial growth. Conclusions: Geraniol inhibits P. polonicum through multiple mechanisms, including membrane disruption, oxidative stress, and interference with energy metabolism, thereby effectively preserving the quality of fresh-cut yam and demonstrating potential as a natural preservative.

The safety and health of food have been persistent concerns, particularly about meat products. Low-temperature meat products refer to those that are processed at lower temperatures. Meat, rich in proteins and other nutrients, is highly susceptible to microbial contamination, leading to spoilage, particularly when processed at lower temperatures that increase storage and transportation requirements. In response to the limitations of conventional preservation methods, such as heat treatment and chemical bacteriostats, emerging preservation technologies are increasingly being adopted. These technologies aim to mitigate the negative effects of microorganisms on meat products. Non-thermal technologies and biotechnological approaches, which are low in energy consumption and energy efficiency, are becoming more prevalent. Non-thermal sterilization technology is widely applied in various food products. It maintains the original quality of food, enhances food safety, reduces energy consumption, and improves production efficiency. Biocides are extensively used in the antibacterial field owing to their high efficiency, low toxicity, and long-lasting properties. Both non-thermal sterilization technology and biocides can ensure food safety, extend the shelf life of food products, improve food quality, meet consumers’ demand for natural and healthy food, enhance market competitiveness, and play a positive role in promoting the sustainable development of the food industry. This paper provides a comprehensive review of the specific applications of biocides and non-thermal sterilization methods in food, highlighting the control parameters and their effects on microbes during low-temperature meat processing, to supply pertinent researchers with theoretical references.

Oxidative stress has been identified as a major cause of cellular injury in a variety of neurodegenerative disorders. This study aimed to investigate the cytoprotective effects of piceatannol on hydrogen peroxide (H₂O₂)-induced pheochromocytoma-12 (PC-12) cell damage and explore the underlying mechanisms. Our findings indicated that piceatannol pre-treatment significantly attenuated H₂O₂-induced PC-12 cell death. Furthermore, piceatannol effectively improved mitochondrial content and mitochondrial function, including enhancing mitochondrial reactive oxygen species (ROS) elimination capacity and increasing mitochondrial transcription factor (TFAM), peroxisome-proliferator-activated receptor-γ coactivator-1α (PGC-1α) and mitochondria Complex IV expression. Meanwhile, piceatannol treatment inhibited mitochondria-mediated autophagy as demonstrated by restoring mitochondrial membrane potential, reducing autophagosome formation and light chain 3B II/I (LC3B II/I) and autophagy-related protein 5 (ATG5) expression level. The protein expression level of SIRT3 was significantly increased by piceatannol in a concentration-dependent manner. However, the cytoprotective effect of piceatannol was dramatically abolished by sirtuin 3 (SIRT3) inhibitor, 3-(1H-1,2,3-Triazol-4-yl) pyridine (3-TYP), which led to an exacerbated mitochondrial dysfunction and autophagy in PC-12 cells under oxidative stress. In addition, the autophagy activator (rapamycin) abrogated the protective effects of piceatannol on PC-12 cell death. These findings demonstrated that piceatannol could alleviate PC-12 cell oxidative damage and mitochondrial dysfunction by inhibiting autophagy via the SIRT3 pathway.

Staphylococcus saprophyticus, the food-borne bacteria present in dairy products, ready-to-eat food and environmental sources, has been reported with antibiotic resistance, raising concerns about food microbial safety. The antimicrobial resistance of S. saprophyticus requires the development of new strategies. Light- and photosensitizer-based antimicrobial photodynamic inactivation (PDI) is a promising approach to control microbial contamination, whereas there is limited information regarding the effectiveness of PDI on S. saprophyticus biofilm control. In this study, PDI mediated by natural bioactive compound (curcumin) associated with LED was evaluated for its potential to prevent and disrupt S. saprophyticus biofilms. Biofilms were treated with curcumin (50, 100, 200 µM) and LED fluence (4.32 J/cm², 8.64 J/cm², 17.28 J/cm²). Control groups included samples treated only with curcumin or light, and samples received neither curcumin nor light. The action was examined on biofilm mass, viability, cellular metabolic activity and cytoplasmic membrane integrity. PDI using curcumin associated with LED exhibited significant antibiofilm activities, inducing biofilm prevention and removal, metabolic inactivation, intracellular membrane damage and cell death. Likewise, scanning electronic microscopy observations demonstrated obvious structural injury and morphological alteration of S. saprophyticus biofilm after PDI application. In conclusion, curcumin is an effective photosensitizer for the photodynamic control of S. saprophyticus biofilm.

Hirudin and its variants, as strong inhibitors against thrombin, are present in the saliva of leeches and are recognized as potent anticoagulants. However, their yield is far from the clinical requirement up to now. In this study, the production of hirudin variant 3 (HV3) was successfully realized by cultivating the recombinant Pichia pastoris GS115/pPIC9K-hv3 under the regulation of the promoter of AOX1 encoding alcohol oxidase (AOX). The antithrombin activity in the fermentation broth reached the maximum value of 5000 ATU/mL. To explore an effective strategy for improving HV3 production in the future, we investigated the influence of methanol assimilation on the general gene expression in this recombinant by transcriptomic study. The results showed that methanol was partially oxidized into CO₂, and the rest was converted into glycerone-P which subsequently entered into central carbon metabolism, energy metabolism, and amino acid biosynthesis. However, the later metabolic processes were almost all down-regulated. Therefore, we propose that the up-regulated central carbon metabolism, energy, and amino acid metabolism should be beneficial for methanol assimilation, which would accordingly improve the production of HV3.