Fumonisin B1 (FB1) is a carcinogenic mycotoxin found in commodities such as corn and corn-originated products. An aptamer-based method for detection of FB1 was developed using the fluorescent dye PicoGreen, which can recognize and bind double-stranded DNA. A peak fluorescence of PicoGreen was obtained in 15 min in the presence of FB1 aptamer, which formed a double-stranded hybridizer DNA with its complementary strand. The excitation and emission wavelengths for PicoGreen detection were 480 nm and 520 nm, respectively. The sensitivity of this aptamer/PicoGreen-based method was 0.1 μg/L. This method showed a good linearity for FB1 concentration ranging from 0.1 to 1 μg/L. The entire detection procedure for FB1 could be completed within 40 min. No cross reactions were observed with any other mycotoxins against aflatoxin B1, ochratoxin A, citrinin and zearalenone, demonstrating high specificity towards FB1 aptamer. Agreement between commercial, antibody-based enzyme-linked immunosorbent assay (ELISA) kit and aptamer method was excellent with a kappa value of 0.857. Taken together, this aptamer/PicoGreen-based method is more cost-effective, time-saving and useful than ELISA for detection of FB1.
Aflatoxin B1 ; Enzyme-Linked Immunosorbent Assay ; Fluorescence ; Fluorescent Dyes ; chemistry ; Fumonisins ; analysis ; Mycotoxins ; analysis ; Ochratoxins ; Organic Chemicals ; chemistry ; Staining and Labeling ; Zea mays

BACKGROUND: There have been many significant advances in the diagnosis and treatment of non-small cell lung cancer (NSCLC). However, the mechanism underlying the progression of NSCLC is still not clear. Plant homodomain finger-like domain-containing protein 5A (PHF5A) plays an important role in processes of chromatin remodeling, morphological development of tissues and organs and maintenance of stem cell pluripotency. This study aims to investigate the role of PHF5A in the proliferation and migration of NSCLC. METHODS: A549 and PC-9 PHF5A overexpression cell lines were constructed. PHF5A expression was decreased in H292 and H1299 cells by using siRNA. Flow cytometry was used to detect the cell cycle. MTT assay and clone formation assay were used to examine the proliferative ability of NSCLC, while migration assay and wound healing assay were performed to evaluate the ability of migration. Western blot analysis was used to measure the expressions of PI3K, p-AKT and the associated downstream factors. RESULTS: Up-regulation of PHF5A in A549 and PC-9 cells increased the proliferation rate, while down-regulation of PHF5A in H292 and H1299 cells inhibited the proliferation rate at 24 h, 48 h and 72 h (P<0.05). The metastatic ability was elevated in the PHF5A-overexpresion groups, while reduced in the PHF5A-down-regulation group (P<0.05). In addition, reduced expression of PHF5A induced cell cycle arrest at G1/S phase (P<0.05). Furthermore, decreased expression of PHF5A reduced the expression levels of PI3K, phosphorylation of AKT, c-Myc (P<0.05) and elevated the expression of p21 (P<0.05). CONCLUSIONS These results demonstrated that PHF5A may play an important role in progression of NSCLC by regulating the PI3K/AKT signaling pathway.
Humans ; Carcinoma, Non-Small-Cell Lung/pathology* ; Lung Neoplasms/pathology* ; Proto-Oncogene Proteins c-akt/metabolism* ; Phosphatidylinositol 3-Kinases/metabolism* ; Cell Line, Tumor ; Cell Proliferation/genetics* ; Cell Movement/genetics* ; Gene Expression Regulation, Neoplastic ; Trans-Activators/genetics* ; RNA-Binding Proteins/metabolism*

We aimed to obtain the recombinant aminopeptidase encoded by Listeria monocytogenes (L. monocytogenes) gene lmo1711, and characterized the enzyme. First, the amino acid sequences of Lmo1711 from L. monocytogenes EGD-e and its homologues in other microbial species were aligned and the putative active sites were analyzed. The putative model of Lmo1711 was constructed through the SWISS-MODEL Workspace. Then, the plasmid pET30a-Lmo1711 was constructed and transformed into E. coli for expression of the recombinant Lmo1711. The his-tagged soluble protein was purified using the nickel-chelated affinity column chromatography. With the amino acid-p-nitroaniline as the substrate, Lmo1711 hydrolyzed the substrate to free p-nitroaniline monomers, whose absorbance measured at 405 nm reflected the aminopeptidase activity. The specificity of Lmo1711 to substrates was then examined by changing various substrates, and the effect of metal ions on the catalytic efficiency of this enzyme was further determined. Based on the bioinformatics data, Lmo1711 is a member of the M29 family aminopeptidases, containing a highly conserved catalytic motif (Glu-Glu-His-Tyr-His-Asp) with typical structure arrangements of the peptidase family. The recombinant Lmo1711 with a size of about 49.3 kDa exhibited aminopeptidase activity and had a selectivity to the substrates, with the highest degree of affinity for leucine-p-nitroaniline. Interestingly, the enzymatic activity of Lmo1711 can be activated by Cd²⁺, Zn²⁺, and is strongly stimulated by Co²⁺. We here, for the first time demonstrate that L. monocytogenes lmo1711 encodes a cobalt-activated aminopeptidase of M29 family.