Does the depth of the Financial Markets matter for establishing Green Growth? Assessing Financial sector's potency in decoupling Economic Growth and Environmental Pollution.

China's 2060 carbon neutrality agenda requires implementation of policies that can decouple its economic growth from environmental pollution. Consequently, establishing green growth in the Chinese economy is of utmost significance. Against this milieu, this study questions whether the depth of Chinese financial markets matters for establishing green growth in China. Besides, the green growth effects of renewable energy use, technological innovation, and urbanization are also examined. Accordingly, quarterly frequency data from 1990Q1 to 2020Q4 are utilized to perform econometric tests that accommodate structural break concerns in data. Overall, the findings reveal that the depth of the Chinese financial markets facilitates the prospects of greening the Chinese economy. Notably, deepening of financial markets is seen to initially inhibit green growth while stimulating it later on; thus, the financial markets' depth-green growth nexus is evidenced to depict a U-shape. On the other hand, green growth in China is also found to be catalyzed by the renewable transformation of the Chinese energy sector and through technological innovation in the long-run. Conversely, urbanization is witnessed to inflict anti-green growth impacts. Furthermore, the causality analysis verifies bi-directional causal associations between renewable energy use and green growth while unidirectional causalities running from financial markets' deepening, technological innovation, and urbanization to green growth are also discovered. Therefore, it is recommended that China should try to persistently develop its stock and debt markets so that clean investment can be boosted to decouple economic growth and environmental pollution. Besides, it is also important to undergo renewable energy transition, develop clean technologies, and design low-energy urbanization strategies.

High molecular weight chitosan oligosaccharide exhibited antifungal activity by misleading cell wall organization via targeting PHR transglucosidases.

The fungal cell wall is an ideal target for the design of antifungal drugs. In this study we used an analog of cell wall polymer, a highly deacetylated high molecular-weight chitosan oligosaccharide (HCOS), to test its effect against pathogenic Candida strains. Results showed that HCOS was successfully incorporated into the dynamic cell wall organization process and exhibited an apparent antifungal activity against both plankton and mature fungal biofilm, by impairing the cell wall integrity. Unexpectedly, mechanistic studies suggested that HCOS exerts its activity by interfering with family members of PHR ß-(1,3)-glucanosyl transferases and affecting the connection and assembly of cell wall polysaccharides. Furthermore, HCOS showed great synergistic activity with different fungicides against Candida cells, especially those in biofilm. These findings indicated HCOS has a great potential as an antifungal drug or drug synergist and proposed a novel antifungal strategy with structure-specific oligosaccharides mimicking cell wall polysaccharide fragments.

Chitosan Oligosaccharides Coupling Inhibits Bacterial Biofilm-Related Antibiotic Resistance against Florfenicol.

The formation of bacterial biofilms has increased the resistance of bacteria to various environmental factors and is tightly associated with many persistent and chronic bacterial infections. Herein we design a strategy conjugating florfenicol, an antibiotic commonly used in the treatment of streptococcus, with the antimicrobial biomaterial, chitosan oligosaccharides. The results demonstrated that the florfenicol-COS conjugate (F-COS) efficiently eradicated the mature Streptococcus hyovaginalis biofilm, apparently inhibiting drug resistance to florfenicol. A quantity of 250 µg/mL F-COS showed effective inhibitory activity against planktonic cells and biofilm of the bacteria, and a 4-fold improvement of the F-COS compared to unmodified florfenicol was observed. Furthermore, the conjugate showed a broad-spectrum activity against both Gram-positive and Gram-negative bacteria. It suggested that F-COS might have a potential for application in the treatment of biofilm-related infections.

Synthesis and Evaluation of a Chitosan Oligosaccharide-Streptomycin Conjugate against Pseudomonas aeruginosa Biofilms.

Microbial biofilms are considerably more resistant to antibiotics than planktonic cells. It has been reported that chitosan coupling with the aminoglycoside antibiotic streptomycin dramatically disrupted biofilms of several Gram-positive bacteria. This finding suggested the application of the covalent conjugate of antimicrobial natural polysaccharides and antibiotics on anti-infection therapy. However, the underlying molecular mechanism of the chitosan-streptomycin conjugate (CS-Strep) remains unclear and the poor water-solubility of the conjugate might restrict its applications for anti-infection therapy. In this study, we conjugated streptomycin with water-soluble chitosan oligosaccharides (COS). Unlike CS-Strep, the COS-streptomycin conjugate (COS-Strep) barely affected biofilms of tested Gram-positive bacteria. However, COS-Strep efficiently eradicated established biofilms of the Gram-negative pathogen Pseudomonas aeruginosa. This activity of COS-Strep was influenced by the degree of polymerization of chitosan oligosaccharide. The increased susceptibility of P. aeruginosa biofilms to antibiotics after conjugating might be related to the following: Suppression of the activation of MexX-MexY drug efflux pump system induced by streptomycin treatment; and down-regulation of the biosynthesis of biofilm exopolysaccharides. Thus, this work indicated that covalently linking antibiotics to chitosan oligosaccharides was a possible approach for the development of antimicrobial drugs against biofilm-related infections.

Heterologous expression and biochemical characterization of a GHF9 endoglucanase from the termite Reticulitermes speratus in Pichia pastoris.

BACKGROUND: Cellulases are of great significance for full utilization of lignocellulosic biomass. Termites have an efficient ability to degrade cellulose. Heterologous production of the termite-origin cellulases is the first step to realize their industrial applications. The use of P. pastoris for the expression of recombinant proteins has become popular. The endoglucanase from Reticulitermes speratus (RsEG), belonging to glycoside hydrolase family 9 (GHF9), has not been produced in P. pastoris yet. RESULTS: A mutant RsEGm (G91A/Y97W/K429A) was successfully overexpressed in P. pastoris. RsEGm, with optimum pH 5.0, was active over the pH range of 4.0 to 9.0, and exhibited superior pH stability over between pH 4.0 and pH 11.0. It displayed the highest activity and good stability at 40 °C, but lost activity quickly at 50 °C. The apparent kinetic parameters of RsEGm against Carboxymethyl Cellulose (CMC) were determined, with K m and V max of 7.6 mg/ml and 5.4 µmol/min•mg respectively. Co2+, Mn2+ and Fe2+ enhanced the activity of RsEGm by 32.0, 19.5 and 11.2% respectively, while Pb2+ and Cu2+ decreased its activity by 19.6 and 12.7% separately. CONCLUSIONS: RsEGm could be overexpressed in P. pastoris. It was stable between pH 4.0 and pH 11.0, and exhibited higher stability at temperatures ≤ 40 °C. This endoglucanase may have potential to be used in the field of laundry, textile and lignocellulose-based biofuels and chemicals.

Overexpression and biochemical characterization of a recombinant psychrophilic endocellulase from Pseudoalteromonas sp. DY3.

Cold-active cellulases have received great attention for both industrial applications and fundamental research because of their high activity at low temperatures and their unique structural characters. In this study, the cold-active endoglucanase CelX from psychrotrophic Pseudoalteromonas sp. DY3 was successfully overexpressed in E. coli, partly purified and characterized in detail. CelX showed the highest activity at pH 5.5, and exhibited moderate activity and superior pH stability over a wide pH range (pH 5.0-pH 9.0). It displayed the highest activity at 45 °C, and kept 34.7% residual activity even at 5 °C. It was stable below 35 °C and lost activity very quickly above 45 °C, which is consistent with its cold adaptability. The apparent kinetic parameters CelX against CMC (carboxymethyl cellulose) were determined, with the Km and kcat values of 6.4 mg/ml and 4.2 s-1 respectively. Mn2+ and Co2+ enhanced the cellulolytic activity of CelX by 28.8% and 20.6% respectively, whereas Pb2+ and Cu2+ inhibited its activity by 14.9% and 6.5% separately. The cold adaptation of CelX is possibly due to the presence of the unusually long linker between the catalytic module and the cellulose-binding domain.

Isolation and Abiotic Stress Resistance Analyses of a Catalase Gene from Ipomoea batatas (L.) Lam.

As an indicator of the antioxidant capability of plants, catalase can detoxify reactive oxygen species (ROS) generated by environmental stresses. Sweet potato is one of the top six most important crops in the world. However, its catalases remain largely unknown. In this study, a catalase encoding gene, IbCAT2 (accession number: KY615708), was identified and cloned from sweet potato cv. Xushu 18. It contained a 1479 nucleotides' open reading frame (ORF). S-R-L, Q-K-L, and a putative calmodulin binding domain were located at the C-terminus of IbCAT2, which suggests that IbCAT2 could be a peroxisomal catalase. Next-generation sequencing (NGS) based quantitative analyses showed that IbCAT2 was mainly expressed in young leaves and expanding tuberous roots under normal conditions. When exposed to 10% PEG6000 or 200 mmol/L NaCl solutions, IbCAT2 was upregulated rapidly in the first 11 days and then downregulated, although different tissues showed different degree of change. Overexpression of IbCAT2 conferred salt and drought tolerance in Escherichia coli and Saccharomyces cerevisiae. The positive response of IbCAT2 to abiotic stresses suggested that IbCAT2 might play an important role in stress responses.