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The assembly line biosynthesis of the powerful anticancer-antiviral didemnin cyclic peptides is proposed to follow a prodrug release mechanism in Tristella bacteria. This strategy commences with the formation of N-terminal prodrug scaffolds and culminates in their cleavage during the cellular export of the mature products. In this study, a comprehensive exploration of the genetic and biochemical aspects of the enzymes responsible for both the assembly and cleavage of the acylated peptide prodrug scaffolds is provided. This process involves the assembly of N-acyl-polyglutamine moieties orchestrated by the nonribosomal peptide synthetase DidA and the cleavage of these components at the post-assembly stage by DidK, a transmembrane CAAX hydrolase homolog. The findings not only shed light on the complex prodrug mechanism that underlies the synthesis and secretion of didemnin compounds but also offer novel insights into the expanded role of CAAX hydrolases in microbes. Furthermore, this knowledge can be leveraged for the strategic design of genome mining approaches aimed at discovering new bioactive natural products that employ similar prodrug biochemical strategies.

The rapid growth of fluctuating power sources, mainly wind and solar energy, has led to severe power imbalances and urgent need for developing the energy storage technology. Pumped storage is the largest and most mature energy storage mode by now and has become the energy storage mainstay in the power grid. Gravity energy storage can also realize similar function, by replacing the storage material "water" in pumped storage with other solid heavy objects. There are relevant reports about gravity energy storage abroad, while still lacking in China so far. In this paper, the present situation of gravity energy storage was analyzed, and a conceptual scheme, which includes the gravity turbine and the up and down storehouses, was proposed by analogy with pumped storage. Meanwhile, the working processes, principles of energy storage and power generation of gravity energy storage were clarified, and the power output formula was derived theoretically. According to scientific conception and comparative analysis, it is preliminarily estimated that the net height of gravity energy storage is about 100 m and the corresponding maximum single unit capacity can reach 10 MW. In addition, distributed planning can be adopted to realize flexible large-scale energy storage. Based on the exploratory analysis, four technology conceptualizations and key problems of gravity energy storage are proposed as follows: 1) The gravity turbine for converting the potential energy of heavy objects into rotating mechanical energy. The gravity turbine is developed which works similarly to the hydraulic turbine, the maximum transport capacity is more than ten tons per second and the target efficiency is 80%. Since the gravity turbine is the critical core component of gravity energy storage, more needs to be studied in the mechanical engineering applications. 2) The suitable layout of up and down storehouses. Combined with the actual geographical conditions, flexibly arrange the up and down storehouses. Using the space between up and down storehouses to store heavy objects can reduce the land occupation. The up and down storehouses layout, gravity turbine and conveying system should be discussed and demonstrated as a whole system since the former can affect the development and research of the others. 3) High efficiency conveying system for heavy objects, including lifting heavy objects from the down storehouse to the up storehouse and transporting them in the same storehouse. Because the commercial value of gravity energy storage is directly related to the conveyance energy consumption and system efficiency, extensive research is needed to find a safe, efficient, and feasible conveying system. 4) Reasonable selection of heavy objects. Concrete as the main material of heavy objects is more appropriate. The construction waste and local material are used as much as possible to reduce the impact on the environment. In addition, heavy objects should be standardization with the same specification and durability for long recycling. All in all, gravity energy storage has the significant advantages of environmental friendliness, flexible layout, high safety, long life, no self-discharge, etc., with outstanding research and development value and broad application prospects. However, gravity energy storage technology is still in the exploration stage. Further investigations of gravity energy storage are needed to promote the pre-study, program planning and technology development, which would provide backup support for the long-term development of new energy. [ABSTRACT FROM AUTHOR]

CO2 supercritical fluid technique with an ethanol modifier was used to extract bamboo (Phyllostachys heterocycla) leave’s polysaccharide (BLPs) regarding various operating conditions. Pressure (30, 40 and 50 MPa), extraction temperature (40, 45 and 50 °C), extraction time (2, 3 and 4 h) and modifier dosage (20, 25 and 30 mL) were important operating factors affecting the yield and total antioxidant activity of each BLPs extraction. The optimal parameters for harvesting the BLPs were an extracting time of 2 h plus 40 MPa pressure with 30 mL of ethanol modifier at 50 °C. In this case, 2.47% BLPs (in wt) was extracted. The BLPs, after purified by D101 macroporous resin and DEAE-cellulose column, with the average molecular weight of 5.05 × 104 Da are composed of rhamnose, fucose, arabinose, xylose, mannose, glucose, and galactose in the molar ratio of 1.318:2.100:1.189:1.016:1:4.776:1.318, respectively. It showed the best antioxidant activity, and its total antioxidant activity of the BLPs extracted was equivalent to 20.70 mg ascorbic acid [(VcE)/g]. In a word, our technique should be potential for producing the best yield and activity of bamboo (Phyllostachys heterocycla) leave’s polysaccharide. [ABSTRACT FROM AUTHOR]