A Surface Molecularly Imprinted Polymer for Selective Extraction and Liquid Chromatographic Determination of 4-Methylimidazole in Environmental Samples

A newly designed surface molecularly imprinted polymer (MIP) was developed using 4-methylimidazole as the template and ethylenediaminepoly (styrene-divinylbenzene) particles as the support material. The resulting MIP material was characterized with scanning electron microscopy, infrared spectrum, surface area, pore-size and thermal property measurements. Static adsorption, solid-phase extraction (SPE) and high-performance liquid chromatography were combined to study the adsorption characteristics and selective recognition performance of the polymer for 4-methylimidazole and its structural analogues. It was shown that the maximum binding capacities of 4-methylimidazole on the MIP and the non-imprinted polymer (NIP) were 416 and 227 µmol g −1 respectively. The binding process could be described by pseudo-second-order kinetics, and the adsorption equilibrium was achieved in 40 minutes. Compared with the corresponding NIP, the MIP exhibited much higher adsorption performance and selectivity for the template. After the separation of a mixture of 4-methylimidazole, benzimidazole and nitrophenol on the MIP–SPE and the NIP–SPE columns, the recoveries of 4-methylimidazole on the MIP–SPE and NIP–SPE columns were 96–102% and 34–39%, respectively, whereas those of benzimidazole and nitrophenol were below 19% on the two columns. In addition, more than 99% of 4-methylimidazole could be obtained on the MIP–SPE column from water and soil samples

Serious diarrhea with weight loss caused by <it>Capillaria philippinensis</it> acquired in China: a case report

Abstract Background Diarrhea caused by Capillaria philippinensis (C. philippinensis) has not been reported in any areas with the exception of Taiwan province in China. We herein report the misdiagnosis and subsequent management of a patient with diarrhea caused by C. philippinensis. Case presentation A 33-year-old woman from the outskirts of Danzhou city, Hainan province, China, had an 11-month history of chronic diarrhea with abdominal pain, edema, hypoalbuminemia, and severe weight loss. The patient was misdiagnosed at an outpatient clinic and one hospital. She was finally correctly diagnosed with C. philippinensis by stool examination. The patient was given a 30-days course of albendazole (400 mg/day) and had an uneventful and stable recovery. Conclusion Doctors cannot lose sight of patients’ dietary histories, must query stool examination results, and need to expand their knowledge of certain nonlocal and global diseases, especially those described in new case reports. Some diagnostic examinations must be performed repeatedly. Hainan province may be the epidemic focus of C. philippinensis.</p

Exosome cofactor hMTR4 competes with export adaptor ALYREF to ensure balanced nuclear RNA pools for degradation and export

The exosome is a key RNA machine that functions in the degradation of unwanted RNAs. Here, we found that significant fractions of precursors and mature forms of mRNAs and long noncoding RNAs are degraded by the nuclear exosome in normal human cells. Exosome-mediated degradation of these RNAs requires its cofactor hMTR4. Significantly, hMTR4 plays a key role in specifically recruiting the exosome to its targets. Furthermore, we provide several lines of evidence indicating that hMTR4 executes this role by directly competing with the mRNA export adaptor ALYREF for associating with ARS2, a component of the cap-binding complex (CBC), and this competition is critical for determining whether an RNA is degraded or exported to the cytoplasm. Together, our results indicate that the competition between hMTR4 and ALYREF determines exosome recruitment and functions in creating balanced nuclear RNA pools for degradation and export

NRDE2 negatively regulates exosome functions by inhibiting MTR4 recruitment and exosome interaction

The exosome functions in the degradation of diverse RNA species, yet how it is negatively regulated remains largely unknown. Here, we show that NRDE2 forms a 1:1 complex with MTR4, a nuclear exosome cofactor critical for exosome recruitment, via a conserved MTR4-interacting domain (MID). Unexpectedly, NRDE2 mainly localizes in nuclear speckles, where it inhibits MTR4 recruitment and RNA degradation, and thereby ensures efficient mRNA nuclear export. Structural and biochemical data revealed that NRDE2 interacts with MTR4's key residues, locks MTR4 in a closed conformation, and inhibits MTR4 interaction with the exosome as well as proteins important for MTR4 recruitment, such as the cap-binding complex (CBC) and ZFC3H1. Functionally, MID deletion results in the loss of self-renewal of mouse embryonic stem cells. Together, our data pinpoint NRDE2 as a nuclear exosome negative regulator that ensures mRNA stability and nuclear export