Search

Highlights • Membrane Contact Sites (MCS) as interfaces for interorganellar communication. • MCSs enable differential intracellular lipid distribution. • MCSs facilitate Ca2+ homeostasis, a conserved signaling agent. Cellular adaptive responses arise from an array of spatially and temporally distinct biochemical interactions that modulate biological processes and reorganize subcellular structures tailored to the nature of stimulus. As such, cells have evolved elegantly and tightly regulated mechanisms to enable interorganellar communication in part through the dynamic readjustment of physical distance enabling the tethering between two closely apposed membranous organelles and thus formation of Membrane Contact Sites (MCSs). MCSs are dynamic and ubiquitous interorganellar structures that serve as regulatory interfaces to facilitate transmission of signals and to integrate synthesis of metabolic pathways such as lipids required for upholding cellular homeostasis in response to environmental and developmental inputs. Endoplasmic reticulum (ER) is the most copious endomembrane system that extend throughout the cell, and functions in production, processing, and transport of proteins and lipids, as well as in intracellular signaling. Reminiscent of the ancient Silk Road, ER connection to other membranous organelles via MCSs alters cellular landscape and serves as nexus for coordinating exchange of metabolites such as lipids, ions such as Ca2+, and other small molecules involved in maintaining cellular integrity under prevailing conditions. Delineating the molecular organization of the tethering complexes, molecular action of exchanged molecules and hence the nature of information transmitted will afford insight into underlying basis of interorganellar communication and shed light on the evolutionarily conserved function of ER as the ancient trans-kingdom Silk Road trafficking vital metabolites via the non-vesicular pathway. [ABSTRACT FROM AUTHOR]

The pupae is one of the most valuable components of the silkworm, a by-product of silk reeling. Employing them as a raw material to create valued products will help to recycle and reuse silkworm pupae, as well as contribute to the food industry's long-term development. Silkworm pupae protein (SPP) and pupae oil (SPO) are high in nutritional and bioactive components that have a variety of applications in the food industry as well as health-promoting characteristics. In this review, we first elaborate on the modification, nutritional, and functional properties of silkworm pupae in terms of requirements for protein and lipids processing as well as current extraction technology. In the subsequent sections, we summarize the modification techniques including the science and technology involved in attaining fatty acid components of SPO. Finally, we focus on recent studies related to the utilization of SPP and SPO subject to their inclusion in foods for their health benefits. The key to silkworm pupae product design may be to fully exploit and utilize the inherent characteristics of the pupae to produce functional peptides and structural lipids with high nutritional content, which may necessitate further improvements in the bioactive and functional properties. Designing more ecologically friendly, low-cost, and efficient processes for producing protein and oil from silkworm pupae is also a trend in technology. This may further provide new insights into the mechanisms behind modifying silkworm pupae as food and its health advantages. [Display omitted] • Modifications and functions of silkworm pupae protein (SPP) and oil (SPO) were reviewed. • Modification of SPP and SPO reveal valuable nutritional properties. • Inclusion of SPP and SPO in food and feed applications were summarized. • Peptide composition in silkworm pupae aid in valuable biological activities. • Further research to compare SPP and SPO with standard proteins and oils is recommended. [ABSTRACT FROM AUTHOR]

• Mulberry anthocyanins were prepared by ATPS biotransformation and HPLC purification. • An ATPS was designed to enhance the conversion of mulberry red pigment from C 3 R to C 3 G. • Whole-cell catalysts containing α -rhamnosidase at the interface of ATPS for easy recovery. • Peak partition collection and post-processing of semi-preparative HPLC was established. • The final purities of C 3 G and C 3 R prepared by semi-preparative HPLC reached 99 %. As a nutritious fruit, mulberry is an ideal source of high-quality cyanidin-3- O -glucoside (C 3 G) with various biological activities. However, the difficult separation process of high-purity C 3 G leads to its high price. To rapidly prepare high-purity C 3 G, cyanidin-3- O -rutinoside is converted to C 3 G by direct hydrolysis of rhamnose bond using a whole-cell catalyst containing α -rhamnosidase. Combined with an aqueous two-phase system, a coupling reaction separation system was established. Two monomers were successfully separated by semi-preparative high performance liquid chromatography (semi-preparative HPLC). The conversion of C 3 G catalyzed by whole-cells in the PEG/Na 2 SO 4 system increased from 47.11 % to 66.56 %, compared with the EtOH/(NH 4) 2 SO 4 system, and the whole-cell activity remained above 50 % after five rounds of reuse. Meanwhile, the purity of C 3 G was increased to 99 % via the semi-preparative HPLC purification and identified by MS. Thus, an integrated process of whole-cell-catalyzed conversion and product peak cutting partition collection provides a novel strategy for efficient biomanufacturing of high-purity C 3 G. [ABSTRACT FROM AUTHOR]

Developing circular economy is the only way to improve the efficiency of resource utilization. Whole-cell catalysis is an effective method to recycle enzymes, improve catalytic efficiency, and reduce production costs. The enzyme, α -L-rhamnosidase has considerable application prospects in the field of biocatalysis as it can hydrolyze a variety of α -L rhamnoses. In the present study, the genes for α -L-rhamnosidase (rhaB1) and enhanced fluorescent protein (EGFP) were co-expressed using a bi-promoter expression vector pRSFDuet1 and their enzymatic properties were evaluated. To our knowledge, this study has established an effective rhamnosidase-fluorescent indicator and whole-cell catalytic system for the first time. Moreover, we analyzed the change in the activity of the crude rhaB1-EGFP as well as its whole-cell during the biocatalysis process using fluorescence intensity. Recombinant rhaB1-EGFP as a product which contains rhaB1 and EGFP showed higher thermal stability, pH stability, and conversion efficiency than rhaB1, and its optimum temperature for rutin catalysis was ideal for industrial applications. Moreover, under the optimal conditions of a rutin concentration of 0.05 g/L, pH of 6.0, temperature of 40 °C, a yield of 92.5% was obtained. Furthermore, we demonstrated the relationship between the fluorescence intensity and enzyme activity. This study established a highly efficient whole-cell catalytic system whose activity can be evaluated by fluorescence intensity, providing a reference for enzyme recycling. Unlabelled Image • Two genes of rhaB1 and EGFP were firstly co-expressed by a bi-promoter expression vector. • Crude rhaB1-EGFP possessed higher thermal and pH stabilities than those of crude rhaB1. • Expression vector activity could be quantitatively detected by measuring fluorescence intensity. • Affinity of rhaB1-EGFP to substrate was not significantly reduced confirmed by SPR assay. • A labeled and recycling whole-cell catalyst was developed for flavonoids transformation. [ABSTRACT FROM AUTHOR]