Liver organoid culture methods

Organoids, three-dimensional structures cultured in vitro, can recapitulate the microenvironment, complex architecture, and cellular functions of in vivo organs or tissues. In recent decades, liver organoids have been developed rapidly, and their applications in biomedicine, such as drug screening, disease modeling, and regenerative medicine, have been widely recognized. However, the lack of repeatability and consistency, including the lack of standardized culture conditions, has been a major obstacle to the development and clinical application of liver organoids. It is time-consuming for researchers to identify an appropriate medium component scheme, and the usage of some ingredients remains controversial. In this review, we summarized and compared different methods for liver organoid cultivation that have been published in recent years, focusing on controversial medium components and discussing their advantages and drawbacks. We aimed to provide an effective reference for the development and standardization of liver organoid cultivation.

Optimization of the fermentation conditions for the mutant strain of β-cyclodextrin glycosyltransferase H167C to produce cyclodextrins

The cyclodextrin glycosyltransferase (CGTase) was used to catalyze the conversion of starch into cyclodextrins (CD) in industry. Improving the activity of CGTase to produce more CD with relative low cost is intensely interesting and has drawn wide attention. Amino acid mutation of His167 into Cys significantly enhanced β-CGTase activity; however, optimization of culture conditions for β-CGTase-H167C remains unclear. To determine this, the medium and culture conditions for β-CGTase-H167C were optimized with response surface methodology. Maximum activity of β-CGTase-H167C was obtained with the medium containing 1.1% corn starch, 4.4% corn steep liquor, 1.1% peptone, 0.02% MgSO₄·7H₂O and 0.1% K₂HPO₄·3H₂O that were cultured with the initial pH 8.4, incubation temperature at 37.4 °C, with 5% inoculation size and shaking speed at 202 r/min. Under the optimal conditions, the activity of β-CGTase-H167C was up to 4355 U/mL, which is 1.93-fold in comparison with the initial activity. Our results established the promising culture strategy for the production of cyclodextrins by β-CGTase-H167C.

The influence of medium components on secondary embryogenesis of winter oilseed rape, Brassica napus L. ssp. oleifera (Metzg.) Sink

The secondary embryogenic potential of Brassica napus L. ssp. oleifera (Metzg.) Sink. ev. Primor could be maintained for many years on complete Murashige and Skoog's medium without diminution. Experiments were conducted to investigate the effects of reducing or deleting certain components of the medium on secondary embryogenesis. Secondary embryogenesis was found to be significantly suppressed when strength of iron in the medium was reduced. Secondary embryogenesis, completely suppressed in 'iron-free' medium, could be regained when iron was incorporated into the medium. Micronutrients and organic nutrients in the medium had no effect on secondary embryogenesis. A reduction in the strength of the medium or its macronutrients decreased secondary embryogenesis significantly.