Evaluation of a dye-decolorizing peroxidase from Comamonas serinivorans for lignin valorization potentials

Although dye-decolourising peroxidases (DyPs) are well-known for lignin degradation, a comprehensive understanding of their mechanism remains unclear. Therefore, studying the mechanism of lignin degradation by DyPs is necessary for industrial applications and enzyme engineering. In this study, a dye-decolourising peroxidase (CsDyP) gene from C. serinivorans was heterologously expressed and studied for its lignin degradation potential. Molecular docking analysis predicted the binding of 2, 2-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), veratryl alcohol (VA), 2, 6-dimethylphenol (2, 6- DMP), guaiacol (GUA), and lignin to the substrate-binding pocket of CsDyP. Evaluation of the enzymatic properties showed that CsDyP requires pH 4.0 and 30 °C for optimal activity and has a high affinity for ABTS. In addition, CsDyP is stable over a wide range of temperatures and pH and can tolerate 5.0 mM organic solvents. Low NaCl concentrations promoted CsDyP activity. Further, CsDyP significantly reduced the chemical oxygen demand decolourised alkali lignin (AL) and milled wood lignin (MWL). CsDyP targets the β-O-4, CO, and CC bonds linking lignin's G, S, and H units to depolymerize and produce aromatic compounds. Overall, this study delivers valuable insights into the lignin degradation mechanism of CsDyP, which can benefit its industrial applications and lignin valorization.

High expression of LINC0163 promotes progression of papillary thyroid cancer by regulating epithelial-mesenchymal transition MITF

OBJECTIVE

The purpose of this study was to detect the expression of long non-coding ribonucleic acid 00163 (LINC00163) in human papillary thyroid cancer (PTC), and to observe the influence of downregulated LINC00163 on the proliferative and metastatic capacities of human PTC cells.

PATIENTS AND METHODS

Quantitative Reverse Transcription-Polymerase Chain Reaction (qRT-PCR) assay was applied to measure the expression level of LINC00163 in PTC tissues and para-carcinoma tissues, as well as that in normal human thyroid cells (Nthy-ori3-1) and PTC cells. After the expression of LINC00163 in PTC cells was interfered, qRT-PCR assay was performed to determine the interference efficiency, and colony formation and Cell Counting Kit-8 (CCK-8) assays were conducted to study the impacts of small interfering (si)-LINC00163 on the proliferative capacity of PTC cells. Moreover, wound healing and transwell assays were adopted to investigate the changes in the migratory and invasive abilities of PTC cells after the interference in the expression of LINC00163 in PTC cells. Finally, the changes in expressions of molecular markers in downstream signaling pathways after interference in LINC00163 expression were examined via Western blotting assay.

RESULTS

In 51 cases of PTC tissues and corresponding para-carcinoma tissues, 41 cases exhibited an up-regulated expression of LINC00163, and qRT-PCR results indicated that PTC cells also had an up-regulated expression of LINC00163 compared with normal human thyroid cells. After the expression of LINC00163 in PTC cells was interfered, the results of colony formation and CCK-8 assays manifested that the proliferative capacity of the cells declined. It was also shown in wound-healing and transwell assay results that the migratory and invasive abilities of the cells were weakened. In addition, the results of Western blotting assay revealed expression changes in the molecular markers of epithelial-mesenchymal transition (EMT).

CONCLUSIONS

The expression of LINC00163 in NSCLC tissues and cells is upregulated, and highly expressed LINC00163 can promote PTC cell proliferation and metastasis by regulating the EMT.

LncRNA MIF-AS1 aggravates the progression of ovarian cancer by sponging miRNA-31-5p

OBJECTIVE

The aim of this study was to uncover the role of lncRNA MIF-AS1 in influencing the biological phenotypes of ovarian cancer (OC) and the underlying mechanism.

PATIENTS AND METHODS

OC tissues and adjacent normal tissues were collected from 50 OC patients. The expression level of lncRNA MIF-AS1 in OC tissues and cells was determined by quantitative Real-Time Polymerase Chain Reaction (qRT-PCR). The prognostic potential of MIF-AS1 in OC patients was assessed by the Kaplan-Meier method. Subsequently, the regulatory effects of MIF-AS1 on proliferative, migratory, and invasive abilities of ES-2 and HO-8910 cells were evaluated by a series of functional experiments. Dual-Luciferase reporter gene assay, qRT-PCR, and Western blot were further conducted to verify the interaction in the regulatory loop MIF-AS1/miRNA-31-5p/PLCB1.

RESULTS

MIF-AS1 was significantly upregulated in OC tissues and cell lines (p<0.05). Higher level of MIF-AS1 predicted significantly worse prognosis of OC patients (p<0.05). The knockdown of MIF-AS1 markedly attenuated the proliferative, migratory, and invasive abilities of ES-2 and HO-8910 cells (p<0.05). Dual-Luciferase reporter gene assay verified that MIF-AS1 competed with PLCB1 to bind miRNA-31-5p. In addition, MIF-AS1 negatively regulated miRNA-31-5p expression cells, and miRNA-31-5p negatively regulated PLCB1 expression in OC.

CONCLUSIONS

MIF-AS1 was significantly upregulated in OC, which accelerated the proliferative, migratory, and invasive abilities of OC cells. Furthermore, the regulatory loop MIF-AS1/miRNA-31-5p/PLCB1 could be utilized as a therapeutic target for OC.

Colonic structural and ion transport abnormalities in suckling rabbits infected with Escherichia coli K12

BACKGROUND

Escherichia coli K12 is a laboratory strain considered nonpathogenic. The purpose of this study was to examine the effect of E. coli K12 infection on colonic structure and function.

METHODS

Suckling rabbits were infected at 10 days of age with 6 x 10(9) CFU E. coli by intragastric inoculation and were examined 4 to 5 days later. Segments of ileum and proximal and distal colon were removed for light and electron microscopy, and NaCl transport was examined in vitro under short-circuited conditions in Ussing chambers.

RESULTS

Infection did not cause weight loss or diarrhea. Colonic mucosa was inflamed with infiltration by polymorphonuclear neutrophils mainly in the lamina propria. The proximal and distal colon exhibited reduced Na+ absorption. The proximal colon also showed increased Cl- secretion; the ileum was unaffected.

CONCLUSIONS

Infection with E. coli K12 disrupts the epithelium and alters ion transport in the colon, probably as a result of mucosal inflammation. The changes indicate that nonpathogenic E. coli have the potential to cause intestinal disease.

Prevalence of verocytotoxigenic Escherichia coli serotype O157:H7 in children with diarrhoea attending a Sydney hospital

Verotoxin producing Escherichia coli, in particular serotype O157:H7, have been implicated as an important cause of acute gastroenteritis in children. This study was undertaken to determine if E. coli O157:H7 is an important cause of acute gastroenteritis in children in metropolitan Sydney. During the period from October 1990 to September 1991, stools from patients presenting with acute diarrhoea to The Children's Hospital, Camperdown, were examined for the presence of common bacterial pathogens. In addition, stools were grown on sorbitol McConkey agar and sorbitol non-fermenting organisms were serotyped with O157 antiserum by slide agglutination. The isolates were then tested with H7 antisera and investigated for the production of verocytotoxin and other pathogenic markers including plasmid-associated EHEC adhesin and chromosomally encoded attachment-effacement gene. Only two strains (isolated from two different patients, 0.1% of specimens tested) were agglutinated by O157 antiserum and both were non-motile (H-). However, both strains produced verotoxin and expressed other virulence markers, suggesting that they were responsible for the diarrhoea. Both patients experienced mild, self limited gastroenteritis. We conclude that E. coli O157:H7 is an uncommon cause of acute gastroenteritis in Sydney children presenting to a children's hospital.

Heat-shock gene expression and cell cycle changes during mammalian embryonic development

Synchronized regulation of cell division during gastrulation is essential for the regional proliferation of cells and pattern formation of the early CNS. The neural plate and neuroectoderm cells are a rapidly dividing and differentiating population of cells with a unique and rapid heat-shock response. Heat shock and the heat-shock genes were studied during neural plate development in a whole rat embryo culture system at 9.5-11.5 days. A lethal shock can cause cell death and severe developmental defects to the forebrain and eye during organogenesis. Heat shock can also result in acquired thermotolerance whereby cell progression is delayed at the G1/S and S/G2 boundaries of the cell cycle. This delay in cell cycle progression caused an overall lengthening of the cell cycle time of at least 2 hr. The heat shock genes may therefore function as cell cycle regulators in neuroectoderm induction and differentiation. The kinetics and expression of the hsp genes were examined in neuroectodermal cells by flow cytometry and Northern analysis. The levels of hsp mRNA 27, 71, 73, and 88 were identified following exposure at 42 degrees C (nonlethal), 43 degrees C (lethal) and 42 degrees/43 degrees C (thermotolerant) heat shock. Examination of hsp gene expression in the neural plate showed tight regulation in the cell cycle phases. Hsp 88 expression was enhanced at Go and hsp71 induction at G2 + M of the cell cycle. Cells exposed to a thermotolerant heat shock of 42 degrees C induced hsp71 mRNA expression in all phases of the cell cycle with the mRNA levels of hsp27, 73, and 88 increased but relatively constant. Following a lethal heat shock, dramatic changes in hsp expression were seen especially enhanced hsp71 induction in late S phase. The regulated expression of hsps during the cell cycle at various phases could play a unique and important role in the fate and recovery of neuroectoderm cells during early mammalian embryo development.

The effectiveness of a training programme upon maximum aerobic power

Forty-two trained and untrained young Chinese subjects of both sexes were employed for this study. Maximal oxygen uptake and anaerobic threshold were measured with the Beckman Metabolic Measurement Cart (MMC) during incremental work test. Skinfold thickness was measured using a skinfold caliper. Body density was calculated with skinfold thickness according to the formula of Suzuki et al (1975). % fat was calculated with the equation given by Brozek et al (1963). % fat of trained subjects was significantly lower than untrained subjects in both sexes. Maximal aerobic power of trained subjects was greater than untrained subjects in both sexes. VO2 at "AT" in trained subjects was greater than untrained subjects in both sexes. Anaerobic threshold might be a valid and useful physiological index for evaluation of physical fitness in various subjects.