Self-assembled Fe3O4-COOH @ hydrogen-bonded organic framework composites for magnetic solid-phase extraction of tetracycline in food samples coupled with HPLC determination.

Magnetic solid-phase extraction (MSPE) technology for tetracycline (TCC) was developed by employing the novel and pre-designed Fe3O4-COOH@hydrogen-bonded organic frameworks (HOFs) adsorbents in complex food samples. The HOF shell was grown onto the Fe3O4-COOH core by in-situ self-assembled method. The excellent MSPE performances with less solvent, less adsorbent and time consumption were derived from the hydrogen bonding, π-π and hydrophobic interactions between HOF shell and TCC. Combined with HPLC analysis, Fe3O4@ HOFs adsorbent reduced matrix effects and the established MSPE-HPLC method for TCC gave the linearity of 0.001-6 µg mL-1 with the limit of detection 0.0003 µg mL-1. The recoveries in pure milk, canned yellow peach and carrot were 82.4-103.7 %. The method provided a simple, efficient and dependable alternative to monitor trace TCC antibiotics in food or environmental samples.

Facile preparation of covalent-organic framework composites for magnetic solid-phase extraction of naphthaleneacetic acid in food prior to HPLC-UV analysis.

Novel magnetic covalent organic frameworks (COFs) were prepared by one-pot synthetic strategy and employed as an efficient adsorbent for magnetic solid-phase extraction (MSPE) of naphthaleneacetic acid (NAA) in food samples. Depending on the predesigned the hydrogen bonding, π-π and hydrophobic interactions of magnetic COFs, the efficient and selective extraction process for NAA was achieved within 15 min. The magnetic COFs adsorbent combined with HPLC-UV was devoted to develop a novel quantitative method for NAA in complex food. The method afforded good coefficient in range of 0.002-10.0 µg mL-1 and low limit of detection was 0.0006 µg mL-1. And the newly established method afforded less adsorbent consumption, wider linearity and lower LODs than the reported analytical methods. Ultimately, the method was successfully applied to determine NAA in fresh pear, tomato and peach juice. The magnetic COFs based MSPE coupled with HPLC-UV method provided a simple, efficient and dependable alternative to monitor trace NAA in food samples.

Retraction notice to "Endogenous production of C-C motif chemokine ligand 2 by nasopharyngeal carcinoma cells drives radioresistance-associated metastasis" [Canc. Lett. 468 (2020) 27-40].

This article has been retracted: please see Elsevier Policy on Article Withdrawal (https://www.elsevier.com/about/our-business/policies/article-withdrawal). .

Expanding the concept of patient-derived xenografts cohorts in head and neck cancer: current and future perspectives.

Head and neck cancer is the seventh common cancer in the world, and various existing treatment strategies provide modest benefit for most patients with head and neck cancer. Meanwhile, therapeutic strategies lacking molecular typing significantly hinder the development of individualized treatment for head and neck cancer. In recent years, connected by preclinical models, the novel ideal has gradually reached a consensus in terms of facilitating inter-transformation of clinical problems and basic achievements. As a bridge between basic research and clinical transformation, patient-derived xenografts (PDX) models precisely replicate genetic characteristics and tumor evolution, which are displaying great vitality in elucidating the mechanism of tumorigenesis and progression. Moreover, cohorts composed of several PDX models highlight the unique advantages of mice for drug screening and biomarker analysis for patients. This ideal preclinical model explores potential treatment strategies suited the ethical standards as much as possible for patients.

Endogenous production of C-C motif chemokine ligand 2 by nasopharyngeal carcinoma cells drives radioresistance-associated metastasis.

Patients with recurrent nasopharyngeal carcinoma (NPC) have more co-existing distant metastasis than those of no-recurrence and are more likely to suffer distant metastasis after re-irradiation than patients with newly diagnosed NPC. However, the relationship between radioresistance and distant metastasis and the mechanisms involved in radioresistance-associated metastasis are still unclear. In this study, we proved that C-C motif chemokine ligand 2 (CCL2) expression was significantly elevated in HONE1-IR cells and recurrent NPC tumour. Inhibition of CCL2 enhanced sensitivity to radiotherapy in NPC cells. Moreover, autocrine CCL2 promoted NPC cell adaptive radioresistance, metastasis and epithelial-mesenchymal transition. Additionally, p53 activated CCL2 transcription. High CCL2 expression was highly associated with poorer locoregional recurrence free survival, progression free survival and overall survival in patients with newly diagnosed NPC. Notably, high CCL2 expression was an independent prognostic factor for distant metastasis free survival in recurrent NPC patients. Our results provide insights into the autocrine signalling mechanisms of CCL2 and suggest that inhibition of autocrine CCL2 may be a candidate treatment strategy for management of radioresistant NPC.

The MYB/miR-130a/NDRG2 axis modulates tumor proliferation and metastatic potential in salivary adenoid cystic carcinoma.

Increasing evidence has emerged to suggest that N-myc downstream-regulated gene 2 (NDRG2) dysregulation participates in a number of tumor biological processes. However, the role of NDRG2 and miRNA-mediated NDRG2 regulation in salivary adenoid cystic carcinoma (SACC) progression remain unknown. Here, we determined that SACC tissues exhibited decreased level of NDRG2, which was associated with poorer rates of overall survival and distant metastasis-free survival. Silencing NDRG2 promoted SACC cell proliferation and metastasis both in vitro and in vivo. MiRNAs have been reported as vital regulators of NDRG2 expression. Based on micronome sequencing of three paired samples of SACC and normal salivary gland tissue and on an online database analysis, miR-130a was identified as a candidate miRNA that potentially regulates NDRG2. We demonstrated that the expression level of NDRG2 was dramatically reduced by exogenous miR-130a. Moreover, a luciferase assay further validated that miR-130a could degrade NDRG2 mRNA by targeting sites in the NDRG2 3'UTR. A rescue experiment suggested that NDRG2 expression could reverse the miR-130a-mediated promotion of cell proliferation and invasion. The expression of miR-130a has been reported to be regulated by certain transcription factors. In the preset study, we verified that the transcription factor MYB acted as the critical driver in SACC-upregulated miR-130a expression directly and induced NDRG2 downregulation in SACC tissues. Additionally, MYB/miR-130a activated the STAT3 and AKT pathways by downregulating NDRG2. These observations suggest that the MYB/miR-130a/NDRG2 axis, which modulates proliferation and metastasis in SACC, provides promising targets for the treatment of SACC.

Effect of cortex mori on pharmacokinetic profiles of main isoflavonoids from pueraria lobata in rat plasma.

ETHNOPHARMACOLOGICAL RELEVANCE: Radix pueraria (the root of pueraria lobata (Wild.) Ohwi.), which contains a class of isoflavonoids as the main active components, as well as cortex mori (the root bark of Morus alba L), which contains abundant active alkaloids, have been employed for the treatment of diabetes in traditional Chinese medicine for centuries. In previous studies, pharmacodynamic synergistic reactions have been observed in compatible application of pueraria lobata isoflavonoids extracts (PLF) and cortex mori alkaloids extracts (CME) for inhibiting α-glycosidase activity. It has also been demonstrated that PLF can effectively slow down the absorption of active alkaloid from CME, so as to produce a higher effective concentration in small intestine for depressing the elevation of postprandial blood glucose through inhibiting α-glycosidase activity. AIM OF THE STUDY: In this study, the hypoglycemic effect of PLF, CME or CME-PLF mixture (the mixture of CME and PLF at a ratio of 1:6.3) was further evaluated through in vivo glucose tolerance studies. And the effect of CME on pharmacokinetic profiles of main isoflavonoids from PLF in rat plasma was investigated to further underlie compatibility mechanism of the two herbs. MATERIALS AND METHODS: Four groups of rats received an oral dose of starch solution alone or simultaneously with drugs by gavage feeding. The blood samples were collected to determine glucose concentrations by glucose oxidase method. In addition, another two groups of rats were orally administered with PLF or CME-PLF. The plasma samples were collected and assayed using an LC/MS/MS method for comparatively pharmacokinetic studies of five main isoflavonoids. RESULTS: For starch loading, co-administration of CME-PLF resulted in more potent inhibition effects on glucose responses compared to those by CME or PLF in rat. The isoflavonoids from PLF were rapidly absorbed, presenting similarly low concentrations in plasma. When CME was added, the Cmax and AUC of all the five isoflavonoids were increased. A phenomenon of double peaks was found for all analysts. The elimination rates of all the detected isoflavonoids were also slowed down with extension of t1/2. CONCLUSIONS: CME has been found to increase the absorption and delay the elimination of main isoflavonoids from PLF, which might result in higher concentrations of circulating active compounds for anti diabetes.

Application and validation of autochthonous Lactobacillus plantarum starter cultures for controlled malolactic fermentation and its influence on the aromatic profile of cherry wines.

Lactic acid bacteria (LAB) used for malolactic fermentation (MLF) has a great effect on the production and quality of cherry wines. The present study used an autochthonous Lb. plantarum strain of SGJ-24 which was isolated from spontaneous MLF cherry wines and selected by its best MLF performance and tolerance, to investigate its effect on the kinetic of vinification and on chemical and volatile characteristics of Rainer and May Duck cherry wines, in comparison with a commercial Oenococcus oeni strain of 31 MBR. Monitoring of MLF was carried out by measuring cell viability and malic acid metabolism, and results showed that for both cherry varieties, SGJ-24 can significantly minimize MLF duration. After fermentation, wine samples were chemically characterized and analyzed for volatile profiles. Results demonstrated that no negative impact on the analytical parameters has been found, and a general increase of volatile esters and terpenes was observed when SGJ-24 was involved. Sensory analysis revealed that the global aromatic intensity was enhanced by the introduction of SGJ-24. All these data suggested that the application of Lb. plantarum strain of SGJ-24 as a worthwhile alternative LAB species for Rainer and May Duck cherry winemaking.

Sequential culture with Torulaspora delbrueckii and Saccharomyces cerevisiae and management of fermentation temperature to improve cherry wine quality.

BACKGROUND: There has been limited research on the use of non-Saccharomyces yeasts for the production of cherry wines. This work used an autochthonous Torulaspora delbrueckii strain 49 (TD49) in association with a commercial S. cerevisiae RC212 yeast, to investigate the effect of multi-starter culture (sequential inoculation and simultaneous inoculation) and fermentation temperature on the quality of cherry wines. RESULTS: Both TD49 and RC212 proliferated during alcoholic fermentation (AF) under sequential inoculation conditions, whereas in the case of simultaneous inoculation, TD49 increased slowly at first and then declined sharply near the fermentation end. The analytical profile showed that both mixed fermentations produced lower levels of volatile acidy and higher levels of aromatic compounds than those from RC212 mono-culture. During sensory analysis, wines from sequential fermentation obtained the highest score, mainly due to the higher intensity in 'fruity' and 'floral' characters. As for the influence of temperature, a low temperature (20 °C) enhanced TD49 persistence during AF, but the sensory quality decreased anyway; 30 °C resulted in decreases in most measured descriptors. Therefore, 25 °C was selected as the best culture temperature. CONCLUSION: TD49/RC212 sequential inoculation and fermentation at 25 °C significantly enhanced the cherry wine quality.

[Expression and localization of FGFR family in squamous cell carcinoma of head and neck].

PURPOSE: To investigate the expression and localization of FGFR family in squamous cell carcinoma of head and neck (SCCHN) cell lines. METHODS: Total protein was extracted from 10 SCCHN cell lines and the expression of FGFR was detected by Western blot. The localization of FGFR was further demonstrated by immunofluorescence staining in SCC25 and HN4 cell lines. Gray value was measured by Image J. GraphPad Prism 5.01 software package was used for data processing and analysis. RESULTS: FGFR1 expression was detected in 6/10 cell lines and FGFR2, 3, 4 was detectable in all cell lines. The expression of FGFR1, 2, 4 was mainly in the nucleus and cytoplasm while FGFR3 was predominantly localized in cytoplasm. CONCLUSIONS: FGFR shows co-expression in SCCHN cell lines, which may be associated with the tumorigenesis and development of SCCHN.

Selected non-Saccharomyces wine yeasts in controlled multistarter fermentations with Saccharomyces cerevisiae on alcoholic fermentation behaviour and wine aroma of cherry wines.

This study examined the effect of mixed fermentation of non-Saccharomyces (Torulaspora delbrueckii ZYMAFLORE Alpha(TD n. Sacch) and Metschnikowia pulcherrima JS22) and Saccharomyces cerevisiae yeasts (D254 and EC1118) on the production of cherry wines, in comparison with commonly used mono-culture. Results obtained during AF demonstrated that negligible inhibitory effect was observed in S. cerevisiae/Alpha pair, whereas a strong antagonistic effect was detected between MJS22 and S. cerevisiae strain, resulting in an early death of MJS22. For volatile components determined, S. cerevisiae/MJS22 couple was found to significantly boost the production of most detected compounds, more particularly in higher alcohols, esters, acids and terpenes; while the characteristic of S. cerevisiae/Alpha pair is an increase in fruity esters, higher alcohols and decrease in acid production. Sensory evaluation revealed that S. cerevisiae/MJS22 pair reinforced sweet, green and fatty notes to the cherry wines, and S. cerevisiae/Alpha trial enhanced the fruity odour and reduced green note.

Evaluation of sequential inoculation of Saccharomyces cerevisiae and Oenococcus oeni strains on the chemical and aromatic profiles of cherry wines.

The current study was carried out to elucidate the effect of sequential inoculation of Saccharomyces cerevisiae (RC212, D254) and Oenococcus oeni (SG26, Lalvin 31 and Uvaferm Alpha) on the production of cherry wines, especially on the chemical and aromatic characteristics. SI-D culture required the shortest period (23 d) to complete the fermentation, while other inoculations needed longer time. Analysis from chemical composition showed that titratable acidity and content of l-malic acid exhibited evident differences among the samples after MLF. For volatile compounds, 49 major components were identified, mostly comprising of alcohols, acids and esters. Cherry wines obtained from SI-B and SI-C showed higher contents of total volatile alcohols, and SI-D wines produced the greatest amount of volatile acids. According to the odour active value (OAV), 9 out of 49 studied volatile components had OAV >1 in all the analyzed wines, while six volatile components showed OAV >1 only for some of them. Furthermore, a sensory analysis was performed to compare the sensory profile of these cherry wines, and results evidenced that wines resulting from different inoculations presented diverse sensory profiles. These findings suggest that sequential inoculations posed a great potential in affecting and modulating the aromatic profile of cherry wines.

Evaluation of different Saccharomyces cerevisiae strains on the profile of volatile compounds and polyphenols in cherry wines.

Tart cherries of 'Early Richmond', widely grown in Shandong (China), were fermented with six different Saccharomyces cerevisiae strains (BM4×4, RA17, RC212, D254, D21 and GRE) to elucidate their influence on the production of volatiles and polyphenols. Acetic acid and 3-methylbutanol were found in the highest concentrations among all identified volatiles with all six yeast strains, followed by 2-methylpropanol and ethyl lactate. RA17 and GRE cherry wines were characterised by a higher amount of esters and acids. D254 wine contained a higher concentration of alcohols. With respect to polyphenols, five phenolic acids and four anthocyanins were identified among all tested samples, with chlorogenic and neochlorogenic acids, cyanidin 3-glucosylrutinoside and cyanidin 3-rutinoside being the major compounds. When using principal component analysis to classify the cherry wines according to the volatiles and polyphenols, they were divided into three groups: (1) RA17 and GRE, (2) RC212 and D254 and (3) BM4×4 and D21.

Cyclic stretching force induces apoptosis in human periodontal ligament cells via caspase-9.

The response of periodontal ligament (PDL) cells to mechanical stimulation is important in the periodontal tissue remodelling. Our previous study showed that cyclic stretching force on PDL cells induced early apoptosis. However, the mechanism of stretching force-induced cell death is unclear. In the present study, we examined whether PDL cells undergo apoptosis by stretching force using the terminal deoxynucleotidyl transferase (TdT)-mediated dUTP-biotin nick-end-labellling method (TUNEL) and investigated the mechanism by which cyclic stretching force initiated apoptosis. We found that PDL cells became aligned regularly and the number of apoptotic cells increased significantly in a time-and force-dependent manner after the application of cyclic stretching force. Caspase-3 activity increased in proportion to the magnitude of the stretching force, and this effect was reduced significantly by a caspase-9 inhibitor, whereas a caspase-8 inhibitor had no such effect. We therefore concluded that the in vitro application of cyclic stretching force can induce apoptosis in PDL cells by activating the caspase-3 via the caspase-9 signalling cascade. Our findings may provide a novel insight into the mechanism of apoptosis induced by stretching force in PDL cells.

Regulation of environmental factors on the expression of a solid-state specific lipase (Lip1) with Rhizopus chinensis by western blot and indirect Elisa.

To identify which solid-state typical environmental factors are involved in the induction of a solid-state special lipase (Lip1), western blot and Elisa based on Lip1 antibody were used. A low water activity played a significant role in the induction of Lip1, as evidenced by the increased expression level (20-46 microg/g dry cell) along with the decrease of water activity (0.927-0.969). Physical barrier against hyphal extension was found to be another required factor, since the expression of Lip1 was significantly enhanced by 3-fold using a membrane with smaller pore size (0.45 and 0.22 microm) covered on top of surface culture.

Novel minor lipase from Rhizopus chinensis during solid-state fermentation: biochemical characterization and its esterification potential for ester synthesis.

Rhizopus chinensis produces two lipases that catalyze ester synthesis when cultured under solid-state fermentation. The Lip2 was purified to homogeneity by ammonium sulphate precipitation, hydrophobic interaction chromatography and gel filtration chromatography. It has an apparent molecular weight of 33 kDa estimated from SDS-PAGE and 32 kDa calculated from analytical gel permeation, with synthetic activity and purification fold of 96.8 U/mg and 138.3, respectively. Maximum hydrolytic activity was obtained at pH 8.0-8.5 and 40 degrees C using pNPP as substrate. Slight activation of the enzyme was observed when Mn(2+) is present. The enzyme was most active on p-nitrophenyl laurate (C12). The purified lipase exhibited maximum synthetic activity at pH memory of 6.0 and 30 degrees C. Most of ethyl esters synthesized by lyophilized enzyme achieved good yields (>90%), and caprylic acid served as the best acyl donor. The enzyme presented a particular affinity for ethanol, n-propanol and n-hexanol, with conversion of 92%, 93% and 92%, respectively, after 20 h incubation.

Membrane-bound 'synthetic lipase' specifically cultured under solid-state fermentation and submerged fermentation by Rhizopus chinensis: a comparative investigation.

Rhizopus chinensis was able to produce synthetic lipases under both solid-state and submerged fermentations. These lipases were extracted from cell membrane using Triton X-100, and purified to homogeneity through ammonium sulfate precipitation, hydrophobic interaction chromatography and gel filtration chromatography. Judging from SDS-PAGE, the specific synthetic lipases associated with SSF (named as SSL) and SmF (named as SML) were different in the apparent molecular mass (62 and 40kDa). In term of hydrolytic activity, both enzymes exhibited maximum values at pH 8.0 and 40 degrees C; SSL appeared to be more pH tolerant and thermostable than SML. PMSF negligibly affected SSL but strongly reduced the activity of SML. Both enzymes showed clear preference for long-chained p-nitrophenyl esters, yielding maximum activity towards p-nitrophenyl palmitate (with SSL) and p-nitrophenyl laurate (with SML). In term of synthetic activity, lyophilized enzymes gave the highest values both at 30 degrees C, but at different pH memories (7.5 for SSL and 6.5 for SML). Most of ethyl esters synthesized by the two enzymes achieved good yields (>90%), and tetradecanoic acid and laurate acid separately served as the best acyl donors.

[Ectopic bone induction in vivo after transplantation of skeletal satellite cells from green fluorescence protein transgenic mouse transfected by adenoviral vectors encoding bone morphogenetic protein-2].

OBJECTIVE: To observe the ability of induced ectopic bone using skeletal muscles satellite cells (SMSCs) from newborn green fluorescence protein (GFP) transgenic mice mediated by Ad-BMP2. METHODS: Transplantation of SMSCs transduced with Ad-BMP2 into back lamb muscles of subfascia in wildtype 129sv mice with a complex of collagen scaffords, then the tissue histologic examination, X ray plain film, fluorescence microscopy were used. RESULTS: Transplantation of SMSCs transfected with Ad-BMP2 into back lamb muscles of subfascia generated ectopic bone formation involving GFP-positive osteoblasts and osteocytes 2 weeks and mature bone formation 4 weeks after transplantation. SMSCs non-transfected with Ad-BMP2 failed to induce ectopic bone formation. CONCLUSION: SMSCs retain differentiation potentitality into osteoblasts in response to Ad-BMP2. They are useful tools for analyzing the process of osteoblast differentiation in vivo after transplantation.

[Isolation, identification, culture and bionomics of skeletal muscles satellite cells from green fluorescent protein transgenic mouse in vitro].

OBJECTIVE: To investigate the green fluorescent protein (GFP) expression and the bionomics of skeletal muscles satellite cells (SMSCs) in vitro in GFP transgenic mouse. METHODS: The newborn transgenic mice were acquired to separate skeletal muscles satellite cells with enzyme digestion method. Cells were cultured and subcultured in vitro. Morphological observation, growth curve were investigated to evaluate the proliferation and differentiation characteristics of skeletal muscles satellite cells, fluorescence microscope was used to observe the GFP expression. The cells were identified by immunocytochemical stain. In the basis of identification of anti-sarcometric actin anti-body, the combination of anti-desmin antibody and DAPI (4, 6-diamidino-2-phenylindole) were used to detect the purification of skeletal muscles satellite cells. RESULTS: Immunocytofluorescence suggested the good retain of GFP fluorescence in skeletal muscles satellite cells. The cells showed strong proliferative ability and they were positive with immunocytochemical stain of anti-sarcometric actin antibody and anti-desmin antibody. The combination of anti-desmin and DAPI stain can be used to determine the purification of SMSCs. CONCLUSION: Skeletal muscles satellite cells cultured in vitro showed strong proliferation and differentiation ability. They are fit to construct the cell bank of tissure engineering and to be a useful tool to explore cells fate after transplantation since these cells retain the expression of GFP.

[Experimental studies of human adipose tissue-derived stromal cells transfected with ad-hBMP-2 gene].

OBJECTIVE: To investigate the possibility of adipose-derived stromal cells (ADSCs) transfeced by adenovirus containing human bone morphogenetic protein-2 (Ad-hBMP-2) gene and their osteogenic potential. METHODS: ADSCs were obtained from inguinal fat tissue of 4 weeks old SD rats. After exposure to adenovirus containing green fluorescent protein(Ad-GFP), fluorescent microscope was used to observe gene transfection effect once 12 hours. After transfected with Ad-hBMP-2, cytochemistry, immmucytochemistry and Western blot were used to examine the expression of alkaline phosphatase (ALP), osteocalcin (OC) and hBMP-2. RESULTS: After exposed to Ad-GFP 12 hours, 52% ADSCs were observed being transfected and 48 hours later reached 95%. The double number time belonged after transfecting with Ad-hBMP-2, and cytochemistry, immucytochemistry and Western blot examines indicated positive results of ALP, OC, hBMP-2 after 48 hours. CONCLUSION: Adipose tissue contains abundant ADSCs which could be transfected as gene vectors by adenovirus, ADSCs transfected with Ad-hBMP-2 can convert to ostoeblasts, and can act as a kind of seed cells for osteo-tissue engineering.