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Offline showrooms develop rapidly to resolve consumers' uncertainty about whether products fit their needs when they purchase online. This paper considers a supply chain where an offline showroom provides experience service for an existing online retailer and intends to introduce a new competing online retailer to satisfy consumers' heterogeneous demand. The offline showroom has better knowledge of demand information due to closer to offline consumers. We examine the impact of competition and the offline showroom's optimal channel cooperation strategy under asymmetric information and analyse the equilibrium results under the optimal strategy to shed light on channel cooperation and information strategy for supply chain members. We find that under asymmetric information competition prompts the offline showroom to conceal information which generates signal cost (negative information effect) and to increase experience service level which creates value (positive service effect). The optimal channel cooperation strategy depends on the trade-off between these effects. We also find that competition increases the existing online retailer's profit in some conditions. Besides, in some conditions information asymmetry harms all supply chain members, which suggests the offline showroom to share information with the online retailers; in some conditions, information asymmetry harms the offline showroom but benefits the online retailers. [ABSTRACT FROM AUTHOR]

Background: Circular RNAs (circRNAs) play a significant role in some diseases by acting as transcription templates. Therefore, analyzing the interaction mechanism between circRNA and RNA-binding proteins (RBPs) has far-reaching implications for the prevention and treatment of diseases. Existing models for circRNA-RBP identification usually adopt convolution neural network (CNN), recurrent neural network (RNN), or their variants as feature extractors. Most of them have drawbacks such as poor parallelism, insufficient stability, and inability to capture long-term dependencies. Methods: In this paper, we propose a new method completely using the self-attention mechanism to capture deep semantic features of RNA sequences. On this basis, we construct a CircSSNN model for the cirRNA-RBP identification. The proposed model constructs a feature scheme by fusing circRNA sequence representations with statistical distributions, static local contexts, and dynamic global contexts. With a stable and efficient network architecture, the distance between any two positions in a sequence is reduced to a constant, so CircSSNN can quickly capture the long-term dependencies and extract the deep semantic features. Results: Experiments on 37 circRNA datasets show that the proposed model has overall advantages in stability, parallelism, and prediction performance. Keeping the network structure and hyperparameters unchanged, we directly apply the CircSSNN to linRNA datasets. The favorable results show that CircSSNN can be transformed simply and efficiently without task-oriented tuning. Conclusions: In conclusion, CircSSNN can serve as an appealing circRNA-RBP identification tool with good identification performance, excellent scalability, and wide application scope without the need for task-oriented fine-tuning of parameters, which is expected to reduce the professional threshold required for hyperparameter tuning in bioinformatics analysis. [ABSTRACT FROM AUTHOR]

In recent years, arginine deiminase (ADI, EC 3.5.3.6) has attracted much attention as a biocatalyst that produces the functional amino acid l‐citrulline from l‐arginine and also as an anticancer enzyme. Here, we identified and characterized a putative ADI from the thermophilic bacterium Halothermothrix orenii. The H. orenii ADI (H‐ADI) protein was expressed in Escherichia coli BL21(DE3) with a specific activity of 91.8 U/mg protein at 55°C and pH 6.5. The enzyme remained at 74% relative activity after incubation at 45°C for 180 min, only 25% at 50°C. The melting temperature was 56°C. H‐ADI is not a metal‐requiring enzyme; Ni2+ slightly improved the catalytic activity. The Km and Vmax for l‐arginine were 55.5 mM and 156.8 μmol/min/mg protein, respectively. Moreover, three residues (Arg183, Arg237, and His273) were key to the formation of l‐citrulline, as analyzed by alanine‐scanning mutagenesis. Finally, the enzymatic synthesis of l‐citrulline was carried out at 50°C with a conversion ratio reaching 99.03%. Together, these findings show that H‐ADI is a promising biocatalyst for the production of l‐citrulline. [ABSTRACT FROM AUTHOR]

A phospholipase D high producing strain with transphosphatidylation activity that is suitable for phosphatidylserine synthesis was screened by our laboratory and named as Streptomyces cinnamoneum SK43.003. The enzyme structural and biochemical properties were investigated using the molecular biology method. A 1521‐bp fragment of the phospholipase D gene from Streptomyces cinnamoneum SK43.003 was amplified by PCR and encoded for 506 amino acids. The primary structure contained two conserved HKD and GG/S motifs. The pld gene was cloned and expressed in Escherichia coli. The purified enzyme exhibited the highest activity at a pH value of 6.0 andtemperature of 60°C. The enzyme was stable within a pH range of 4–7 for 24 h or at temperatures below 50°C. In addition, Triton X‐100, Fe2+, and Al3+ were beneficial to the enzyme activity, whereas Zn2+ and Cu2+ dramatically inhibited its activity. In a two‐phase system, the enzyme could convert phosphatidylcholine to phosphatidylserine with a 92% transformation rate. [ABSTRACT FROM AUTHOR]

As a committed step in the urea cycle, arginase cleaves l-arginine to form l-ornithine and urea. l-Ornithine is essential to: cell proliferation, collagen formation and other physiological functions, while the urea cycle itself converts highly toxic ammonia to urea for excretion. Recently, arginase was exploited as an efficient catalyst for the environmentally friendly synthesis of l-ornithine, an abundant nonprotein amino acid that is widely employed as a food supplement and nutrition product. It was also proposed as an arginine-reducing agent in order to treat arginase deficiency and to be a means of depleting arginine to treat arginine auxotrophic tumors. Targeting arginase inhibitors of the arginase/ornithine pathway offers great promise as a therapy for: cardiovascular, central nervous system diseases and cancers with high arginase expression. In this review, recent advances in the characteristics, structure, catalytic mechanism and preparation of arginase were summarized, with a focus being placed on the biotechnical and medical applications of arginase. In particular, perspectives have been presented on the challenges and opportunities for the environmentally friendly utilization of arginase during l-ornithine production and in therapies. [ABSTRACT FROM AUTHOR]