Investigation of non-classical secretion of oxalate decarboxylase in Bacillus mojavensis XH1 mediated by exopeptide YydF: Mechanism and application.

Non-classical secretory proteins are widely found in bacteria and have been extensively studied due to their important physiological roles. However, the relevant non-classical secretory mechanisms remain unclear. In this study, we found that oxalate decarboxylase (Bacm OxDC) from Bacillus mojavensis XH1 belongs to non-classical secretory proteins. Its N-terminus showed high hydrophilicity, which was different from the conventional signal peptide. The truncation test revealed that the deletion of the N-terminus affects the structure resulting in its inability to cross the cell membrane. Further studies verified that the exported peptide YydF played an important role in the secretion process of Bacm OxDC. Experimental results on the secretion mechanism indicated that Bacm OxDC bound to the exported peptide YydF and they are translocated to the cell membrane together, after which Bacm OxDC caused cell membrane relaxation for transmembrane secretion. Thereafter, three recombinant proteins were successfully secreted with certain enzymatic activity by fusing Bacm OxDC as a guide protein with various target proteins. To the best of our knowledge, this was the first time that non-classical secretion mechanism in bacteria has been analyzed. The novel discovery may provide a reference and broaden the horizons of the secretion pathway and expression regulation of proteins.

Dodecenylsuccinic anhydride-modified oxalate decarboxylase loaded with magnetic nano-Fe3O4@SiO2 for demulsification of oil-in-water emulsions.

The inability to demulsify oil-in-water emulsions via green and efficient processes is a challenging problem in many industrial processes. As a novel biodemulsifier, protein demulsifiers display excellent dispersibility and stability, but their demulsification mechanisms are not clear, which severely restricts their large-scale production and application. In this study, the demulsification mechanism of the high-efficiency protein biodemulsifier oxalate decarboxylase (Bacm OxdC), which is secreted by the Bacillus mojavensis XH1 strain, for an oil-in-water emulsion was analyzed. The results showed that Bacm OxdC was spontaneously adsorbed at the oil-water interface and turned its hydrophobic amino acids outward to increase its hydrophobicity and break the emulsified system. Furthermore, it effectively reduced the oil-water interfacial tension and interfacial film strength, thereby reducing the oil-water interfacial energy and finally enabling demulsification. To further improve the demulsification efficiency and reusability, Fe3O4@SiO2@OxdC-DDSA was prepared. This method provided a magnetic response for Bacm OxdC and enabled efficient demulsification. The demulsification rate of Fe3O4@SiO2@OxdC-DDSA reached 98.1% at 24 h, which was 30.7% higher than that of the original Bacm OxdC. After three cycles, the demulsification rate still reached 89.3%, proving it has excellent recyclability. This work is the first study on the demulsification mechanism of protein biodemulsifiers and provides useful insights into the demulsification mechanism of biodemulsifiers for oil-in-water emulsions. In addition, a promising high-efficiency modification technique for protein biodemulsifiers was proposed, which provided information for the development of biodemulsifiers for oil-water separation.

Enhancement of Adiponectin Ameliorates Nonalcoholic Fatty Liver Disease via Inhibition of FoxO1 in Type I Diabetic Rats.

Nonalcoholic fatty liver disease (NAFLD) is a common liver disease which has been previously shown to be associated with type 2 diabetes mellitus (T2DM). Recent research has indicated that type 1 diabetes mellitus (T1DM) is also involved in the development of nonalcoholic fatty liver disease, whereas the underlying mechanisms are largely unknown. Forkhead box O1 (FoxO1) and adiponectin (APN) have been proposed to play an important role in the processes in NAFLD in T1DM. We herein investigated the effects of FoxO1 and APN on the development of NAFLD and the underlying mechanism in streptozotocin-induced T1DM. Serum liver enzymes AST, ALT, and triglyceride (TG) were determined by commercially available kits. Blood glucose levels were measured by the OneTouch Ultra glucose meter. Relevant protein expression was tested by Western blot analysis. Results showed that serum AST, ALT, and TG were all significantly increased in T1DM rats, which was ameliorated by application of APN or selective inhibition of FoxO1 with AS1842856. Moreover, APN and AS1842856 both decreased the expression of liver nuclear FoxO1 which was significantly increased in diabetic rats. However, the inhibition of FoxO1 did not alter the expression of APN and its receptors. We also found that Akt1 expression was significantly declined in diabetic rat which was restored by APN and moderately and significantly increased by FoxO1 inhibition. It is concluded that APN ameliorates NAFLD via inhibition of FoxO1 through Akt1/FoxO1 signaling pathway.

Risk factors for osteoporosis in liver cirrhosis patients measured by transient elastography.

Osteoporosis or osteopenia is a common complication in patients with cirrhosis, but little is known about the risk factors for the occurrence of osteoporosis.Patients with liver cirrhosis due to chronic virus infection and alcoholic abuse were enrolled. Bone mineral density (BMD) was determined using dual-energy x-ray absorptiometry (DXA). Osteoporosis was diagnosed according to WHO criteria. The severity of liver stiffness was measured by Fibroscan. Demographic data, such as age, gender, weight, height, and body mass index (BMI), were collected. Logistic regression analysis was used to recognize the risk factors of osteoporosis in patients with cirrhosis.A total of 446 patients were included in this study: 217 had liver cirrhosis (male, 74.2%; mean age, 57.2 ±â€Š10.27) and 229 were matched controls (male, 69%, mean age, 56.69 ±â€Š9.37). Osteoporosis was found in 44 patients (44/217, 20.3%). The spine and hip BMD in cirrhotic patients were significantly lower than that in controls. When the cirrhotic and control subjects were stratified by age, gender, and BMI, the significant difference was also observed in women patients, patients older than 60, and patients with BMI < 18. Multivariate analysis showed that the older age [odds ratio (OR) = 1.78, P = .046], lower BMI (OR = 0.63, P = .049), greater fibroscan score (OR = 1.15, P = .009), and liver cirrhosis induced by alcohol liver disease (OR = 3.42, P < .001) were independently associated with osteoporosis in cirrhotic patients.Osteoporosis occurred in about one-fifth of patients with liver cirrhosis, which was associated with age, BMI, Fibroscan score, and alcohol liver disease related liver cirrhosis.

Upregulation of miR­598 promotes cell proliferation and cell cycle progression in human colorectal carcinoma by suppressing INPP5E expression.

Colorectal cancer (CRC) is one of the most common types of cancer worldwide. Recently, microRNAs (miRs) have been considered as novel therapeutic targets for the treatment of cancer. miR­598 is a poorly investigated miR. The underlying mechanism of miR­598 in CRC cells remains to be elucidated. In the present study, miR­598 was demonstrated to be significantly upregulated in CRC tissue by analyzing data from The Cancer Genome Atlas and the Gene Expression Omnibus. The results of a polymerase chain reaction demonstrated that miR­598 expression was significantly upregulated in CRC tissues and cells. Gain of function and loss of function assays demonstrated that miR­598 significantly promoted cell proliferation and cell cycle progression. miR­598 was demonstrated to modulate cell functions by regulating 72 kDa inositol polyphosphate­5­phosphatase (INPP5E). In addition, knockdown of INPP5E counteracted the growth arrest caused by an miR­598­inhibitor. In conclusion, the present study demonstrated that miR­598 contributed to cell proliferation and cell cycle progression in CRC by targeting INPP5E.

Long non-coding RNA SPRY4-IT1 pormotes colorectal cancer metastasis by regulate epithelial-mesenchymal transition.

Colorectal cancer (CRC) remains one of the most common cancers worldwide. Increasing evidence indicates that SPRY4 intronic transcript 1 (SPRY4-IT1) regulate cell growth, differentiation, apoptosis, and cancer progression. However, the expression and function of SPRY4-IT1 in the progression of CRC remains largely unknown. Here, we reported that SPRY4-IT1 was upregulated in CRC. Increased SPRY4-IT1 expression in CRC was associated with larger tumor size and higher clinical stage. In vitro experiments revealed that SPRY4-IT1 knockdown significantly inhibited CRC cell proliferation by causing G1 arrest and promoting apoptosis, whereas SPRY4-IT1 overexpression promoted cell proliferation. Further functional assays indicated that SPRY4-IT1 overexpression significantly promoted cell migration and invasion by regulate the epithelial-mesenchymal transition (EMT). Taken together, our study demonstrates that SPRY4-IT1 could act as a functional oncogene in CRC, as well as a potential therapeutic target to inhibit CRC metastasis.