Continuous purification of porcine lipase by rotating annular size-exclusion cnromatography

Crude porcine lipase (triacylglycerol lipase, EC 3.1.1.3) was purified in a single-stage Chromatographic process. The purification was accomplished in a batch, as well as in a continuous system. Two types of sizeexclusion packing materials (Sephadex and Sephacryl) were used. The average x-fold increase in purity, and the average recovered activity in the batch Sephadex and Sephacryl experiments were 13.6 and 89.7%, and 34.2 and 98.8%, respectively. The average x-fold increase in purity and the average activity recovered in the continuous Sephadex and Sephacryl experiments were 27.1 and 82.5% and 16.2 and 89%, respectively. Flow visualization experiments were carried out by tagging the protein to be separated with a fluorescent dye. The results from these experiments are also reported in this article.     

One-pot Multicomponent Synthesis of Highly Functionalized 1,4-Dihydropyridines Using Porcine Pancreatic Lipase

A series of highly timctionalized 1,4-dihydropyridines was synthesized via one-pot multicomponent reactions of aromatic aldehyde,malononitrile and N-methyl-1-(methylthio)-2-nitroethenamine using Porcine pancreatic lipase(PPL)as catalyst in DMSO.This protocol is featured by mild reaction conditions,simple operation and environmental acceptability.     

The use of ultrasound-stimulated acoustic emission in the monitoring of modulus changes with temperature

It has been previously shown that the amplitude of the ultrasound-stimulated acoustic emission (USAE) signal is sensitive to tissue temperature and, therefore, can help detect it. Its amplitude, however, is sensitive to both acoustical and mechanical parameters, that at most frequencies have opposite effects due to temperature. In this paper, we explore the feasibility of using a frequency shift of the resonant peaks of the USAE signal for monitoring the tissue stiffness variation with temperature. In a numerical simulation, the variation of the frequency shift at different temperatures is shown. Then, in a series of experiments involving a gel phantom and porcine muscle tissue, the frequency shift variation is shown to follow the known stiffness changes due to temperature. It is also shown that this shift indicates reversible changes as well as the onset of thermal coagulative necrosis. The necrosis is marked by a monotonically increasing positive frequency shift. It was thus shown that the USAE spectrum peaks undergo a negative shift (or, downshift) when the stiffness decreases and a positive shift (or, upshift) when the stiffness increases. The experimental frequency shifted around a peak at 22.1-22.5 kHz within a range of -250 to 80 Hz and -200 to 250 Hz for the gel and muscle tissue for the temperatures of 25-70 and 30-70 degrees C, respectively. Simulation and ex vivo experimental results indicate that the USAE frequency shift method can help decouple the mechanical from the acoustical parameter dependence as well as detect the onset of thermal coagulative necrosis.     

Cellular proteomic analysis of porcine circovirus type 2 and classical swine fever virus coinfection in porcine kidney‐15 cells using isobaric tags for relative and absolute quantitation‐coupled LC‐MS/MS

Viral coinfection or superinfection in host has caused public health concern and huge economic losses of farming industry. The influence of viral coinfection on cellular protein abundance is essential for viral pathogenesis. Based on a coinfection model for porcine circovirus type 2 (PCV2) and classical swine fever virus (CSFV) developed previously by our laboratory, isobaric tags for relative and absolute quantitation (iTRAQ)‐coupled LC‐MS/MS proteomic profiling was performed to explore the host cell responses to PCV2‐CSFV coinfection. Totally, 3932 proteins were identified in three independent mass spectrometry analyses. Compared with uninfected cells, 304 proteins increased (fold change >1.2) and 198 decreased (fold change <0.833) their abundance in PCV2‐infected cells (p < 0.05), 60 and 61 were more and less abundant in CSFV‐infected cells, and 196 and 158 were more and less abundant, respectively in cells coinfected with PCV2 and CSFV. Representative differentially abundant proteins were validated by quantitative real‐time PCR, Western blotting and confocal laser scanning microscopy. Bioinformatic analyses confirmed the dominant role of PCV2, and indicated that mitochondrial dysfunction, nuclear factor erythroid 2‐related factor 2 (Nrf2)‐mediated oxidative stress response and apoptosis signaling pathways might be the specifical targets during PCV2‐CSFV coinfection.     

Acyclic phenylalkanediols as substrates for the study of enzyme recognition: synthesis of substrates and enzymatic resolution via hydrolysis and transesterification

Different racemic or prochiral phenyl alkane (l,n)-diols were synthesized, and their resolution was carried out by two different strategies: enzymatic transesterification with vinyl acetate, or enzymatic hydrolysis of their corresponding diacetates, in both cases catalysed by porcine pancreatic lipase (PPL). The absolute configuration of the optically enriched reaction products was determined by formation of Mosher's esters or by the use of the Benzene Sector and Benzene Chirality Rules as obtained from the Circular Dichroism spectra.     

猪肝中克伦特罗和沙丁胺醇的毛细管电泳-质谱联用分析

盐酸克仑特罗和沙丁胺醇等均属激动剂类药物,人体的累计摄入量超过一定值或食用了高残留的内脏组织,易出现毒副作用[1],因此许多国家都将其列为违禁药物。近年来一些不法饲养业主受利益驱使,将沙丁胺醇(salbutamol)作为“瘦肉精”的替代品在生猪养殖中非法使用。关于克伦特罗和     

Efficacy of transgene expression in porcine skin as a function of electrode choice

Gene electrotransfer is a non-viral technique using electroporation for gene transfection. The method is widely used in the preclinical setting and results from the first clinical study in tumours have been published. However, the preclinical studies, which form the basis for the clinical trials, have mainly been performed in rodents and the body of evidence on electrode choice and optimal pulsing conditions is limited.We therefore tested plate and needle electrodes in vivo in porcine skin, which resembles human skin in structure. The luciferase (pCMV-Luc) gene was injected intradermally and subsequently electroporated. Simultaneously, studies with gene electrotransfer to porcine skin using plasmids coding for green fluorescent protein (GFP) and betagalactosidase were performed.Interestingly, we found needle electrodes to be more efficient than plate electrodes (p < 0.001) and electric field calculations showed that penetration of the stratum corneum led to much more homogenous field distribution at the DNA injection site. Furthermore, we have optimised the electric pulse regimens for both plate and needle electrodes using a range of high voltage and low voltage pulse combinations.In conclusion, our data support that needle electrodes should be used in human clinical studies of gene electrotransfer to skin for improved expression.     

Visualisation of liposomes prepared from skin and stratum corneum lipids by transmission electron microscopy

Transmission electron microscopy was used to visualize the liposomes prepared from total lipids extracted from mouse, human and porcine skin and stratum corneum. The total lipid composition was monitored by high precision thin layer chromatography coupled with a flame identification detector (HPTLC/FID, Iatroscan) and the fatty acid content of the samples was monitored by gas chromatography. The liposomes were prepared by the thin lipid film hydration method and they were visualized by transmission electron microscopy after negative staining using uranyl acetate. The structure of the vesicular structures present in the formulations largely depended on the lipid composition of the samples. The liposomes with high ceramide content were drop like vesicles with sharp tips, whereas the presence of excessive phospholipid content lead to bag like liposomes with two hemispheres divided by a membrane. Finally, the tendency of triacylglycerides to accumulate in the lipophylic region of the lipid bilayer, forms membranes with uneven thickness, resulting in structures with undulated membranes. A degree of fusion depending on the phospholipid content was also observed.     

Determination of β2-Agonists in Porcine Urine by Molecularly Imprinted Solid Phase Extraction Followed Ultra-Performance Liquid Chromatography–Tandem Mass Spectrometry Detection

A novel, sensitive, and robust method has been developed to detect 9 β₂-agonists in porcine urine to monitor illegal use of β₂-agonists in swine rearing. The method based on the molecular imprinted polymer (MIP) rapid extraction followed ultra-performance liquid chromatography coupled tandem mass spectrometry (UPLC-MS/MS) detection. The cleaning efficiency of MIP cartridges was demonstrated by comparing with common ion exchange solid phase extraction. The presented method was validated in accordance with the European Commission Decision 2002/657/EC. The linearity, decision limit (CCα), detection capability (CCβ), recovery, precision, robustness, and stability were studied in detail. CCα and CCβ values were from 0.006 ng/mL to 0.03 ng/mL and from 0.02 ng/mL to 0.08 ng/mL, respectively. The mean recoveries and repeatability varied from 68.8% to 94.2% and from 2.8% to 10.1%. The proposed method was applied to test 170 porcine urine samples from the Shaanxi province in China and two urine samples were confirmed as clenbuterol positive and the concentrations of clenbuterol in positive urine samples were about 0.08 ng/mL and 0.1 ng/mL, respectively. The developed method was demonstrated to be more sensitive and robust for the determination of 9 β₂-agonists in porcine urine. The method was proven to be simple and easy in operation with high selectivity and good reproducibility.