Search Results (9)

To find a suitable medium for muscle satellite cells of Larimichthys crocea, herein, the effect of different basal media and coating materials on the proliferation of piscine satellite cells (PSCs) was explored. Firstly, two basal media, namely F10 and DMEM/F12, were selected as experimental materials, and high-sugar DMEM was the main basal culture medium used with fish muscle cells as a control. The results showed that the PSCs proliferated better in F10 than in DMEM/F12 or DMEM. Secondly, the effects of rat tail collagen, polylysine and matrix coatings, as compared with no coating, on the proliferation and later differentiation of PSCs were also investigated. Our results indicated that there was no significant difference between coating and no coating on the proliferation of PSCs in the F10-based medium. Meanwhile, it was found that the myotubes were washed out, and only those under matrix-coated conditions remained intact in the process of differentiation. The results also suggested that PSCs could still differentiate into myotubes without their stemness being affected after proliferation in the F10-based medium. Hence, this study identified an efficient proliferation medium based on F10 basal medium that could shorten the culture time and maintain the stemness of PSCs, thus providing a basis for large-scale cell expansion and cell-culture-based meat production in the future. Full article

Icariin is the most effective bioactive compound in Herba Epimedii. To enhance the content of icariin in the epimedium water extract, a novel strain, Papiliotrema laurentii ZJU-L07, producing an intracellular α-L-rhamnosidase was isolated from the soil and mutagenized. The specific activity of α-L-rhamnosidase was 29.89 U·mg⁻¹ through purification, and the molecular mass of the enzyme was 100 kDa, as assayed by SDS-PAGE. The characterization of the purified enzyme was determined. The optimal temperature and pH were 55 °C and 7.0, respectively. The enzyme was stable in the pH range 5.5–9.0 for 2 h over 80% and the temperature range 30–40 °C for 2 h more than 70%. The enzyme activity was inhibited by Ca²⁺, Fe²⁺, Cu²⁺, and Mg²⁺, especially Fe²⁺. The kinetic parameters of K_m and V_max were 1.38 mM and 24.64 μmol·mg⁻¹·min⁻¹ using pNPR as the substrate, respectively. When epimedin C was used as a nature substrate to determine the kinetic parameters of α-L-rhamnosidase, the values of K_m and V_max were 3.28 mM and 0.01 μmol·mg⁻¹·min⁻¹, respectively. The conditions of enzymatic hydrolysis were optimized through single factor experiments and response surface methodology. The icariin yield increased from 61% to over 83% after optimization. The enzymatic hydrolysis method could be used for the industrialized production of icariin. At the same time, this enzyme could also cleave the α-1,2 glycosidic linkage between glucoside and rhamnoside in naringin and neohesperidin, which could be applicable in other biotechnological processes. Full article

Betulinic acid, a pentacyclic triterpene, is distributed in a variety of plants, such as birch, eucalyptus and plane trees. It shows a wide spectrum of biological and pharmacological properties, such as anti-inflammatory, antibacterial, antiviral, antidiabetic, antimalarial, anti-HIV and antitumor effects. Among them, the antitumor activity of betulinic acid has been extensively studied. However, obtaining betulinic acid from natural resources can no longer meet the needs of medicine and nutrition, so methods such as chemical synthesis and microbial biotransformation have also been used to prepare betulinic acid. At the same time, with the development of synthetic biology and genetic engineering, and the elucidation of the biosynthetic pathways of terpenoid, the biosynthesis of betulinic acid has also been extensively researched. This article reviews the preparation of betulinic acid and its pharmacological activities, in order to provide a reference for the research and utilization of betulinic acid. Full article

Endophytic fungi infect plant tissues by evading the immune response, potentially stimulating stress-tolerant plant growth. The plant selectively allows microbial colonization to carve endophyte structures through phenotypic genes and metabolic signals. Correspondingly, fungi develop various adaptations through symbiotic signal transduction to thrive in mycorrhiza. Over the past decade, the regulatory mechanism of plant-endophyte interaction has been uncovered. Currently, great progress has been made on plant endosphere, especially in endophytic fungi. Here, we systematically summarize the current understanding of endophytic fungi colonization, molecular recognition signal pathways, and immune evasion mechanisms to clarify the transboundary communication that allows endophytic fungi colonization and homeostatic phytobiome. In this work, we focus on immune signaling and recognition mechanisms, summarizing current research progress in plant-endophyte communication that converge to improve our understanding of endophytic fungi. Full article

Flavonoids belong to a class of plant secondary metabolites that have a polyphenol structure. Flavonoids show extensive biological activity, such as antioxidative, anti-inflammatory, anti-mutagenic, anti-cancer, and antibacterial properties, so they are widely used in the food, pharmaceutical, and nutraceutical industries. However, traditional sources of flavonoids are no longer sufficient to meet current demands. In recent years, with the clarification of the biosynthetic pathway of flavonoids and the development of synthetic biology, it has become possible to use synthetic metabolic engineering methods with microorganisms as hosts to produce flavonoids. This article mainly reviews the biosynthetic pathways of flavonoids and the development of microbial expression systems for the production of flavonoids in order to provide a useful reference for further research on synthetic metabolic engineering of flavonoids. Meanwhile, the application of co-culture systems in the biosynthesis of flavonoids is emphasized in this review. Full article

To evaluate the novel strategy of oleic acid and fungal elicitor (made from Aspergillus niger) to elicit betulinic acid biosynthesis in medicinal mushroom Inonotus obliquus, we conduct the stimulatory effects investigation for synthesizing betulinic acid from betulin. HPLC results indicated oleic acid and fungal elicitor were effective stimulators. The supplementation of 1.0 g/L oleic acid led to the highest increase of betulinic acid either in dry mycelia or fermentation broth by 2-fold of the control. Fungal elicitor at 45 mg/L markedly increases mycelia growth by 146.0% and enhance intracellular betulinic acid accumulation by 429.5% as compared to the controls. Quantification of transcription levels determined that oleic acid, fungal elicitor and their combinations could induce the expressions of key genes involved in betulinic acid biosynthesis, such as HMG-CoA reductase and squalene synthase. These findings indicated that oleic acid and fungal elicitor could enhance betulinic acid metabolism by up-regulating key genes expression. Full article

Glycolipid biosurfactants are natural amphiphiles and have gained particular interest recently in their biodegradability, diversity, and bioactivity. Microbial infection has caused severe morbidity and mortality and threatened public health security worldwide. Glycolipids have played an important role in combating many diseases as therapeutic agents depending on the self-assembly property, the anticancer and anti-inflammatory properties, and the antimicrobial properties, including antibacterial, antifungal, and antiviral effects. Besides, their role has been highlighted as scavengers in impeding the biofilm formation and rupturing mature biofilm, indicating their utility as suitable anti-adhesive coating agents for medical insertional materials leading to a reduction in vast hospital infections. Notably, glycolipids have been widely applied to the synthesis of novel antimicrobial materials due to their excellent amphipathicity, such as nanoparticles and liposomes. Accordingly, this review will provide various antimicrobial applications of glycolipids as functional ingredients in medical therapy. Full article

Ethyl carbamate (EC) is a potential carcinogen that forms spontaneously during Chinese rice wine fermentation. The primary precursor for EC formation is urea, which originates from both external sources and arginine degradation. Urea degradation is suppressed by nitrogen catabolite repression (NCR) in Saccharomyces cerevisiae. The regulation of NCR is mediated by two positive regulators (Gln3p, Gat1p/Nil1p) and two negative regulators (Dal80p/Uga43p, Deh1p/Nil2p/GZF3p). DAL80 revealed higher transcriptional level when yeast cells were cultivated under nitrogen-limited conditions. In this study, when DAL80-deleted yeast cells were compared to wild-type BY4741 cells, less urea was accumulated, and genes involved in urea utilization were up-regulated. Furthermore, Chinese rice wine fermentation was conducted using dal80Δ cells; the concentrations of urea and EC were both reduced when compared to the BY4741 and traditional fermentation starter. The findings of this work indicated Dal80p is involved in EC formation possibly through regulating urea metabolism and may be used as the potential target for EC reduction. Full article

In this work, using Saccharomyces cerevisiae as a model, we showed that BetA could inhibit cell proliferation and lead to lethal cytotoxicity accompanying programmed cell death (PCD). Interestingly, it was found that vacuolar protease Pep4p played a pivotal role in BetA-induced S. cerevisiae PCD. The presence of Pep4p reduced the damage of BetA-induced cells. This work implied that BetA may induce cell death of S. cerevisiae through mitochondria-mediated PCD, and the deletion of Pep4 gene possibly accelerated the effect of PCD. The present investigation provided the preliminary research for the complicated mechanism of BetA-induced cell PCD regulated by vacular protease Pep4p and lay the foundation for understanding of the Pep4p protein in an animal model. Full article