Polyacrylamide (PAM) is a water-soluble polymer that is widely used as a flocculant in sewage treatment. The accumulation of PAM affects the formation of dewatered sludge and potentially produces hazardous monomers. In the present study, the bacterial strain HI47 was isolated from dewatered sludge. This strain could metabolize PAM as its sole nutrient source and was subsequently identified as Pseudomonas putida. The efficiency of PAM degradation was 31.1% in 7 days and exceeded 45% under optimum culture condition (pH 7.2, 39 °C and 100 rpm). The addition of yeast extract and glucose improved the bacterial growth and PAM degradation. The degraded PAM samples were analyzed by gel-filtration chromatography, Fourier transform infrared and high-performance liquid chromatography. The results showed that high-molecular-weight PAM was partly cleaved to small molecular oligomer derivatives and part of the amide groups of PAM had been converted to carboxyl groups. The biodegradation did not accumulate acrylamide monomers. Based on the SDS-PAGE and N-terminal sequencing results, the PAM amide groups were converted into carboxyl groups by a PAM-induced extracellular enzyme from the aliphatic amidase family.

The presence of cancer stem cells (CSCs) is a major cause of therapeutic failure in a variety of cancer types, including colorectal cancer (CRC). However, the underlying mechanisms that regulate the self-renewal of colorectal cancer stem cells (CRCSCs) remain unclear. Our previous study utilized CRCSCs and their parent cells; through gene microarray screening and bioinformatics analysis, we hypothesized that microRNA (miR)-8063 may bind to, and regulate the expression of, heterogeneous nuclear ribonucleoprotein AB (hnRNPAB) to facilitate the regulation of CRCSC self-renewal. The aim of the present study was to confirm this conjecture through relevant experiments. The results indicated that compared with that in parent cells, miR-8063 expression was significantly downregulated in CRCSCs, while hnRNPAB expression was increased. Furthermore, hnRNPAB was identified as a direct target of miR-8063 using a dual-Luciferase assay. Overexpression of hnRNPAB promoted the acquisition of CSC characteristics in CRC cells (increased colony formation ability, enhanced tumorigenicity, and upregulated expression of CSC markers), as well as the upregulation of key proteins (Wnt3a, Wnt5a and β-catenin) in the Wnt/β-catenin signaling pathway. Similarly, after silencing miR-8063 in CRC cells, the characteristics of CSC were altered, and the expression of hnRNPAB protein was promoted. However, post overexpression of miR-8063 in CRCSCs, the self-renewal ability of CSCs was weakened with the downregulation of hnRNPAB protein, Wnt3a, Wnt5a and β-catenin. These results suggest that as a tumor suppressor, miR-8063 is involved in regulating the self-renewal of CRCSCs, where loss of miR-8063 expression weakens its inhibition on hnRNPAB, which leads to the activation of Wnt/β-catenin signaling to promote the self-renewal of CRCSCs.

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Corn ear rot has been the most important disease of the world. It is mainly caused by Fusarium moniliforme which produce a number of mycotoxins including Fumonisin B1 (FB1). Aiming at supplying a potentially effective biological control agent against F. moniliforme, Bacillus megaterium MHT6 isolated from China, was tested for its antagonistic activity against F. moniliforme. Moreover, both antifungal activity and the active compound of strain MHT6 were tested and identified. In order to improve its antifungal activity, a random mutagenesis generated using He-Ne laser irradiation was applied on B. megaterium MHT6. After the mutation, one hundred bacterial colonies were obtained and their effects against F. moniliforme were assessed in a plate assay. Eight colonies (8%) exhibited higher inhibition activity as compared to the wild type MHT6. Among them, the mutant MHT 88 which showed the strongest antagonistic ability was selected out. Through bacterial motility assays, the mutant MHT88 showed stronger swarming motility than wild type MHT6. According to FPLC and MALDI-TOF-MS, the production of two main antagonistic lipopeptides such as surfactin and fengycin increased in mutant MHT88. Especially the surfactin, which can't be detected in the wild strain MHT6, was obviously observed in mutant. Moreover, the cell-free supernatant of the mutant MHT88 showed stronger capability in degrading FB1 compared to MHT6. This study provided a promising biological agent to inhibit F. moniliforme and suppress corn ear rot disease.