Rational design for thermostability improvement of a novel PL-31 family alginate lyase from Paenibacillus sp. YN15.

Currently, alginate oligosaccharides (AOS) become attractive due to their excellent physiological effects. AOS has been widely used in food, pharmaceutical, and cosmetic industries. Generally, AOS can be produced from alginate using alginate lyase (ALyase) as the biocatalyst. However, most ALyase display poor thermostability. In this study, a thermostable ALyase from Paenibacillus sp. YN15 (Payn ALyase) was characterized. It belonged to the polysaccharide lyase (PL) 31 family and displayed poly ß-D-mannuronate (Poly M) preference. Under the optimum condition (pH 8.0, 55 °C, 50 mM NaCl), it exhibited maximum activity of 90.3 U/mg and efficiently degraded alginate into monosaccharides and AOS with polymerization (DP) of 2-4. Payn ALyase was relatively stable at 55 °C, but the thermostability dropped rapidly at higher temperatures. To further improve its thermostability, rational design mutagenesis was carried out based on a combination of FireProt, Consensus Finder, and PROSS analysis. Finally, a triple-point mutant K71P/Y129G/S213G was constructed. The optimum temperature was increased from 55 to 70 °C, and the Tm was increased from 62.7 to 64.1 °C. The residual activity after 30 min incubation at 65 °C was enhanced from 36.0 % to 83.3 %. This study provided a promising ALyase mutant for AOS industrial production.

Studying financial aspect of green credit and regional heterogeneity on technology innovation in China.

This study examines the impact of green credit on digital technology innovation in China, focusing on the influence of financialization and regional heterogeneity. Existing research primarily explores factors like government subsidies, economic growth, and environmental regulations, and there is a lack of critical analysis on the influence of green credit on digital technology innovations. To examine the internal mechanisms linking green credit to digital technology innovation, this study uses panel data from 271 Chinese prefecture-level cities from 2000 to 2020. Our findings suggest that the availability of green credit and the level of financialization have a significant positive effect on technology innovation, particularly in regions with higher economic development. However, we also find that the impact of green credit and financialization on technology innovation varies across different regions of China. Study findings reveal that green credit bolsters both the quantity and quality of digital technology innovation, emerging as a significant driver for green innovations in China. This conclusion holds even after endogeneity tests. The heterogeneous analysis highlights that various aspects of green credit, such as coverage scope, usage intensity, and digitization level, can enhance digital technology innovations. Western cities demonstrate the most considerable positive effects, followed by central cities, while the weakest impact occurs in eastern cities. Green credit primarily promotes digital technology innovation indirectly by alleviating financing constraints. These empirical findings provide valuable policy insights for fostering a harmonious relationship between China's urban green credit facilities and green financial growth, thereby addressing the funding limitations green credit enterprises face.

RBBP4 is an epigenetic barrier for the induced transition of pluripotent stem cells into totipotent 2C-like cells.

Cellular totipotency is critical for whole-organism generation, yet how totipotency is established remains poorly illustrated. Abundant transposable elements (TEs) are activated in totipotent cells, which is critical for embryonic totipotency. Here, we show that the histone chaperone RBBP4, but not its homolog RBBP7, is indispensable for maintaining the identity of mouse embryonic stem cells (mESCs). Auxin-induced degradation of RBBP4, but not RBBP7, reprograms mESCs to the totipotent 2C-like cells. Also, loss of RBBP4 enhances transition from mESCs to trophoblast cells. Mechanistically, RBBP4 binds to the endogenous retroviruses (ERVs) and functions as an upstream regulator by recruiting G9a to deposit H3K9me2 on ERVL elements, and recruiting KAP1 to deposit H3K9me3 on ERV1/ERVK elements, respectively. Moreover, RBBP4 facilitates the maintenance of nucleosome occupancy at the ERVK and ERVL sites within heterochromatin regions through the chromatin remodeler CHD4. RBBP4 depletion leads to the loss of the heterochromatin marks and activation of TEs and 2C genes. Together, our findings illustrate that RBBP4 is required for heterochromatin assembly and is a critical barrier for inducing cell fate transition from pluripotency to totipotency.

Characterization of a thermostable PL-31 family alginate lyase from Paenibacillus ehimensis and its application for alginate oligosaccharides bioproduction.

Currently, people pay more attention to marine sugars, because of their unique physiological effects. Alginate oligosaccharides (AOS) are the degradation products of alginate and have been used in food, cosmetic, and medicine fields. AOS display good physical characteristics (low relative molecular weight, good solubility, high safety, and high stability) and excellent physiological functions (immunomodulatory, antioxidant, antidiabetic, and prebiotic activities). Alginate lyase plays a key role in the AOS bioproduction. In this study, a novel PL-31 family alginate lyase from Paenibacillus ehimensis (paeh-aly) was identified and characterized. It was extracellularly secreted in E. coli and exhibited a preference for the substrate poly ß-D-mannuronate. Using sodium alginate as the substrate, it showed the maximum catalytic activity (125.7 U/mg) at pH 7.5 and 55 °C with 50 mM NaCl. Compared with other alginate lyases, paeh-aly exhibited good stability. About 86.6% and 61.0% residual activity could be maintained after 5 h incubation at 50 and 55 °C respectively, and its Tm value was 61.5 °C. The degradation products were AOS with DP 2-4. Paeh-aly demonstrated strong promise for AOS industrial production because of its excellent thermostability and efficiency.

Collective Total Syntheses of Benzo[c]phenanthridine Alkaloids via a Sequential Transition Metal-Catalyzed Pot-Economic Approach.

Collective total syntheses of 10 benzo[c]phenanthridines were achieved on the basis of the construction of rings C and B through sequential transition metal-catalyzed reactions and flexible condition-controlled Mannich reaction via three pots in 25-34% yields, which provided an efficient route to benzo[c]phenanthridines via a pot-economic approach.

R-loops coordinate with SOX2 in regulating reprogramming to pluripotency.

R-loops modulate genome stability and regulate gene expression, but the functions and the regulatory mechanisms of R-loops in stem cell biology are still unclear. Here, we profiled R-loops during somatic cell reprogramming and found that dynamic changes in R-loops are essential for reprogramming and occurred before changes in gene expression. Disrupting the homeostasis of R-loops by depleting RNaseH1 or catalytic inactivation of RNaseH1 at D209 (RNaseH1D209N) blocks reprogramming. Sox2, but not any other factor in the Yamanaka cocktail, overcomes the inhibitory effects of RNaseH1 activity loss on reprogramming. Sox2 interacts with the reprogramming barrier factor Ddx5 and inhibits the resolvase activity of Ddx5 on R-loops and thus facilitates reprogramming. Furthermore, reprogramming efficiency can be modulated by dCas9-mediated RNaseH1/RNaseH1D209N targeting the specific R-loop regions. Together, these results show that R-loops play important roles in reprogramming and shed light on the regulatory module of Sox2/Ddx5 on R-loops during reprogramming.

Neo-adjuvant chemotherapy plus surgery versus surgery alone for cervical cancer: Meta-analysis of randomized controlled trials.

The aim of this study was to evaluate the efficacy and safety of neo-adjuvant chemotherapy (NACT) versus radical surgery (RS) for patients with cervical cancer. A meta-analysis of randomized controlled trials (RCT) of NACT + RS versus RS alone for patients with cervical cancer was performed according to the guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) statement. The following electronic databases were searched from their inception to April 2015: PUBMED, EMBASE and Cochrane Library. Statistical analysis was done using REVIEW MANAGER 5.3. Five RCT involving 739 patients were studied. There were significant differences between the NACT + RS and the RS-alone groups for positive lymph nodes (OR, 0.45; 95%CI: 0.29-0.70) and parametrial infiltration (OR, 0.48; 95% CI: 0.25-0.92), while treatment efficacy did not differ significantly for 5-year overall survival rate (OR, 1.17; 95% CI: 0.85-1.61), 5-year disease-free survival rate (OR, 1.09; 95% CI: 0.77-1.56) or recurrence rate (OR, 1.17; 95% CI: 0.85-1.61). The results also indicated that chemotherapy-related toxicity was well tolerated. For patients with cervical cancer, NACT could significantly reduce the number of positive lymph nodes and the level of parametrial infiltration compared with RS alone, and be well tolerated.

A low level of GPR37 is associated with human hepatocellular carcinoma progression and poor patient survival.

GPR37, also known as parkin-associated endothelin-like receptor (Pael-R), is an orphan G protein-coupled receptor (GPCR). It has been reported that GPCRs play vital roles in the development and progression of cancer. To investigate the potential roles of GPR37 in hepatocellular carcinoma (HCC), expression of GPR37 was examined in human HCC samples. Immunohistochemistry and Western blot analyses were performed for GPR37 in 57 hepatocellular carcinoma samples. GPR37 expression was low in hepatocellular carcinoma as compared with the adjacent non-tumorous tissues. Clinicopathological analysis showed that GPR37 expression was significantly correlated with histological grade and the level of alpha fetal protein (AFP) (P = 0.000 and 0.002, respectively). The Kaplan-Meier survival curves revealed that decreasing GPR37 expression was associated with poor prognosis in HCC patients, while in vitro, following the release from serum starvation of HuH7 HCC cell, the expression of GPR37 was downregulated. In addition, the transient GPR37 knockdown by siRNA in HuH7 cells significantly decreased the apoptosis of hepatoma cells with activation of the phosphatidylinositol 3-kinase-Akt signaling pathway. Our data suggest that GPR37 may play an important role in the pathogenesis of hepatocellular carcinoma by affecting the proliferation of H CC cells, and it could be a novel potential molecular therapy target for HCC.

Glycinamide ribonucleotide formyl transferase is frequently overexpressed in glioma and critically regulates the proliferation of glioma cells.

AIMS: Current treatments for the most common form of brain tumor, glioma, are disappointing in their effectiveness. Low expression levels of GART, an enzyme in the core nucleotide metabolism, significantly correlate with chemosensitivity, conferring a survival advantage to tumor cells. Our study aimed to explore the expression and function of GART in glioma. METHODS: Immunohistochemical and Western blot analysis were performed in 70 cases of human gliomas and normal brain tissues. We mainly used cell growth assay and multicellular tumor spheroid formation assay to evaluate the proliferation and chemosensitivity of glioma cells. RESULTS: High GART expression (most cancer cells cytoplasm stained) was observed in 70 specimens and was related to the grade of malignancy. We also reviewed each grade of tumors separately and investigated whether GART expression predicted patient survival within each subgroup. In brief, GART overexpression was significantly associated with overall survival (P=0.03). Interestingly, transfecting cells with GART-siRNA suppressed proliferation and enhanced temozolomide (TMZ)-induced apoptosis in glioma cells. CONCLUSION: The current results showed that GART expression was associated with glioma grade and that high GART protein expression might be related to poor outcome.

The role of the orphan G protein-coupled receptor 37 (GPR37) in multiple myeloma cells.

The orphan G protein-coupled receptor 37 (GPR37) is homologous to endothelin (ETB-R) and bombesin (GRP-R, NMB-R) receptors. The present study was undertaken to determine the expression and functional significance of GPR37 in human multiple myeloma (MM). We found that GPR37 was lowly expressed in MM cell adhesion model and highly expressed in proliferating cells. In vitro, meddling with the expression of GPR37 affected the CAM-DR by regulating the ability of cell adhesion and the activity of Akt and ERK in MM cells. Further studies indicated the positive role of GPR37 in the proliferation of MM cells.

FBP1 and p27kip1 expression after sciatic nerve injury: implications for Schwann cells proliferation and differentiation.

Far Upstream Element (FUSE) Binding Protein 1 (FBP1), first identified as a single-stranded DNA (ssDNA) binding protein that binds to the FUSE, could modulate c-myc mRNA levels and also has been shown to regulate tumor cell proliferation and replication of virus. Typically, FBP1 could active the translation of p27kip1 (p27) and participate in tumor growth. However, the expression and roles of FBP1 in peripheral system lesions and repair are still unknown. In our study, we found that FBP1 protein levels was relatively higher in the normal sciatic nerves, significantly decreased and reached a minimal level at Day 3, and then returned to the normal level at 4 weeks. Spatially, we observed that FBP1 had a major colocation in Schwann cells and FBP1 was connected with Ki-67 and Oct-6. In vitro, we detected the decreased level of FBP1 and p27 in the TNF-α-induced Schwann cells proliferation model, while increased expression in cAMP-induced Schwann cells differentiation system. Specially, FBP1-specific siRNA-transfected SCs did not show fine and longer morphological change after cAMP treatment and had a decreased motility compared with normal. At 3 days after cAMP treatment and SC/neuron co-cultures, p27 was transported to cytoplasm to form CDK4/6-p27 to participate in SCs differentiation. In conclusion, we speculated that FBP1 and p27 were involved in SCs proliferation and the following differentiation in the sciatic nerve after crush by transporting p27 from nucleus to cytoplasm.

Suppression of KIF3B expression inhibits human hepatocellular carcinoma proliferation.

BACKGROUND: Human hepatocellular carcinoma (HCC) is one of the most common fatal cancers and an important health problem worldwide, but its mechanism is still unclear. Microtubule (MT) kinesin motor proteins orchestrate a variety of cellular processes (e.g. mitosis, motility and organelle transportation) and have been involved in human carcinogenesis. KIF3B, the kinesin superfamily of proteins (KIFs), plays an important role in the regulation of mitotic progression. AIM: The expression of KIF3B and its involvement in HCC was investigated. METHODS: Western blot and immunohistochemistry were used to measure the expression of KIF3B protein in HCC and adjacent non-tumorous tissues in 57 patients and Cell Counting Kit-8 to analyze the effects of growth and interference of KIF3B in the cell cycle process. RESULTS: KIF3B protein level was increased in HCC tissues compared with the adjacent non-tumorous tissues. It was significantly associated with histological differentiation, tumor size, the level of alpha fetal protein (AFP) and proliferation marker Ki-67. Over-expression of KIF3B was correlated with poor survival. Following release of HepG2 cells from serum starvation, the expression of KIF3B was up-regulated. Furthermore, suppression of KIF3B not only decreased cancer cell growth but also induced apoptosis of cells. CONCLUSIONS: Our results suggested that KIF3B expression was upregulated in HCC tumor tissues and proliferating HCC cells, and an increased KIF3B expression was associated with poor overall survival. KIF3B over-expression is involved in the pathogenesis of hepatocellular carcinoma and may serve as a potential therapeutic target for human HCC.

Low expression of cyclic AMP response element modulator-1 can increase the migration and invasion of esophageal squamous cell carcinoma.

Cyclic AMP response element-binding protein (CREB) family can regulate biological functions of various types of cells and has relation with esophageal cancer cell migration and invasion. Cyclic AMP response element modulator-1 (CREM-1) is one member of the family with limited acquaintance. This study was conducted to investigate the effect of CREM-1 on migration and invasion in human esophageal squamous cell carcinoma (ESCC). The expression of CREM-1 protein in ESCC tissues with or without lymph nodes metastasis was determined by western blot. Immunohistochemical analysis of CREM-1 expression were carried out in paraffin-embedded sections of ESCC and correlated with clinical features. The roles of CREM-1 in migration and invasion were studied in TE1 cells through knocking CREM-1 down with siRNA or overexpression of CREM-1 in ECA109 cells. The regulations of CREM-1 on invasion and migration were determined by transwell and wounding healing assay. The effect of CREM-1 on chemotherapy drug was analyzed by Cell counting kit-8 assay. We found that the expression of CREM-1 was significantly downregulated in ESCC tissues with lymph nodes metastasis compared with the tissues without lymph nodes metastasis and was correlated with the clinical features of pathological grade, tumor stage and lymph node metastasis. Moreover, knocking CREM-1 down with siRNA increased cell migration and invasion in human ESCC cell lines TE1 while upregulation of CREM-1 inhibited the motility. Our data suggested that CREM-1 might play an important role in the regulation of tumor metastasis and invasion and serve as a tumor suppressor in human ESCC. We proposed that CREM-1 might be used as a potential therapeutic agent for human ESCC.