Jianyu Su

Unnoticed Spread of Class 1 Integrons in Gram‐Positive Clinical Strains Isolated in Guangzhou, China

A total of 46 gram‐positive bacteria isolated from clinical specimens collected in China were subjected to PCR analysis with the intI1‐specific primers, and the intI1‐positive strains were further analyzed for their resistance gene cassette. All isolates possessed the class 1 integron in their genomes and the array of gene cassettes was dhfrXII‐orfF‐aadA2, which is very similar to other organisms except in one isolate carrying an additional copy of the class 1 integron containing the aadA2 gene cassette. Altogether, the results indicate that the class 1 integron is widespread in gram‐positive clinical strains isolated in Guangzhou, China.

Investigation of the interaction of naringin palmitate with bovine serum albumin: spectroscopic analysis and molecular docking.

Background Bovine serum albumin (BSA) contains high affinity binding sites for several endogenous and exogenous compounds and has been used to replace human serum albumin (HSA), as these two compounds share a similar structure. Naringin palmitate is a modified product of naringin that is produced by an acylation reaction with palmitic acid, which is considered to be an effective substance for enhancing naringin lipophilicity. In this study, the interaction of naringin palmitate with BSA was characterised by spectroscopic and molecular docking techniques. Methodology/Principal Findings The goal of this study was to investigate the interactions between naringin palmitate and BSA under physiological conditions, and differences in naringin and naringin palmitate affinities for BSA were further compared and analysed. The formation of naringin palmitate-BSA was revealed by fluorescence quenching, and the Stern-Volmer quenching constant (KSV) was found to decrease with increasing temperature, suggesting that a static quenching mechanism was involved. The changes in enthalpy (ΔH) and entropy (ΔS) for the interaction were detected at −4.11±0.18 kJ·mol−1 and −76.59±0.32 J·mol−1·K−1, respectively, which indicated that the naringin palmitate-BSA interaction occurred mainly through van der Waals forces and hydrogen bond formation. The negative free energy change (ΔG) values of naringin palmitate at different temperatures suggested a spontaneous interaction. Circular dichroism studies revealed that the α-helical content of BSA decreased after interacting with naringin palmitate. Displacement studies suggested that naringin palmitate was partially bound to site I (subdomain IIA) of the BSA, which was also substantiated by the molecular docking studies. Conclusions/Significance In conclusion, naringin palmitate was transported by BSA and was easily removed afterwards. As a consequence, an extension of naringin applications for use in food, cosmetic and medicinal preparations may be clinically and practically significant, especially in the design of new naringin palmitate-inspired drugs.

Natural Borneol, a Monoterpenoid Compound, Potentiates Selenocystine-Induced Apoptosis in Human Hepatocellular Carcinoma Cells by Enhancement of Cellular Uptake and Activation of ROS-Mediated DNA Damage

Selenocystine (SeC) has been identified as a novel compound with broad-spectrum anticancer activities. Natural borneol (NB) is a monoterpenoid compound that has been used as a promoter of drug absorption. In the present study, we demonstrated that NB significantly enhanced the cellular uptake of SeC and potentiated its antiproliferative activity on HepG2 cells by induction of apoptosis. NB effectively synergized with SeC to reduce cancer cell growth through the triggering apoptotic cell death. Further mechanistic studies by Western blotting showed that treatment of the cells with NB and SeC activated the intrinsic apoptotic pathway by regulation of pro-survival and pro-apoptotic Bcl-2 family proteins. Treatment of the cells with NB and SeC induced the activation of p38MAPK and inactivation of Akt and ERK. NB also potentiated SeC to trigger intracellular ROS generation and DNA strand breaks as examined by Comet assay. Moreover, the thiol-reducing antioxidants effectively blocked the occurrence of cell apoptosis, which confirmed the important role of ROS in cell apoptosis. Taken together, these results reveal that NB strongly potentiates SeC-induced apoptosis in cancer cells by enhancement of cellular uptake and activation of ROS-mediated DNA damage. NB could be further developed as a chemosensitizer of SeC in treatment of human cancers.

Development and application of a novel multiplex polymerase chain reaction (PCR) assay for rapid detection of various types of staphylococci strains

In this study, a novel multiplex- polymerase chain reaction (PCR) for rapid detection of various staphylococci strains, including methicillin-resistant Staphylococcus aureus (MRSA), methicillin-sensitive Staphylococcus aureus, (MSSA) methicillin-resistant coagulase-negative staphylococci (MRCNS), methicillin-sensitive coagulase-negative staphylococci (MSCNS) and non-staphylococci strains, had been developed and applied. Six primers were specially designed on three target genes, which were mecA, 16S Ribosomal ribonucleic acid (rRNA) and femA. The specific amplification generated 3 bands on agarose gel, with sizes 374 bp for mecA, 542 bp for 16S rRNA and 823 bp for femA, respectively. The PCR product showed highest levels of resolution of DNA when 250 �M of dNTP, primer concentration of mecA, 16S rRNA and femA reaching 1, 1 and 3 �M respectively. No false positive amplification was observed, indicating the high specificity of the established multiplex PCR assay. Application of this multiplex-PCR had been further performed on detection for 262 MRSA and MRCNS strains with primers pairs M1 with M2 and F1 and F2. According to the results, multiplex-PCR results showed expected products for either MRSA or MRCNS strains, demonstrating the multiplex-PCR assays established in this study to be useful and powerful methods for differentiation of MRSA, MSSA, MRCNS, MSCNS and non-staphylococci strains.

Mechanical, Rheological and Release Behaviors of a Poloxamer 407/ Poloxamer 188/Carbopol 940 Thermosensitive Composite Hydrogel

The aims of this study were to prepare a thermosensitive composite hydrogel (TCH) by mixing 24% (w/v) poloxamer 407 (P407), 16% (w/v) poloxamer 188 (P188) and 0.1% (w/v) carbopol 940 (C940), and to determine the effect of natural borneol/ (2-hydroxypropyl)-β-cyclodextrin (NB/HP-β-CD) inclusion complex on the phase transition temperature, mechanical, rheological properties, and release behaviors of the TCH using the tube inversion method, a texture analyzer, a rheometer, and in vitro release , respectively. The results showed that as the concentration of NB/HP-β-CD increased, the phase transition temperature of the TCH was increased from 37.26 to 38.34 °C and the mechanical properties of the TCH showed that the hardness, cohesiveness, strength, and adhesiveness were increased from 0.025 to 0.064 kg, 0.022 to 0.064 kg, 0.110 to 0.307 kg and 0.036 to 0.105 kg, respectively, but the rheological properties of the TCH showed that G′, G′′ and η were decreased from 7,760 to 157.50 Pa, 1,274 to 36.28 Pa and 1,252 to 25.37 Pas, respectively. The in vitro release showed that an increasing NB/HP-β-CD concentration decreased the release rate of NB from the TCH, but the amount of NB released was more than 96% at 60 min, which showed the TCH had good release behavior.

Synergistic apoptosis-inducing effects on A375 human melanoma cells of natural borneol and curcumin.

This study was to investigate the synergistic effect of NB/Cur on growth and apoptosis in A375 human melanoma cell line by MTT assay, flow cytometry and Western blotting. Our results demonstrated that NB effectively synergized with Cur to enhance its antiproliferative activity on A375 human melanoma cells by induction of apoptosis, as evidenced by an increase in sub-G1 cell population, DNA fragmentation, PARP cleavage and caspase activation. Further mechanistic studies by Western blotting showed that after treatment of the cells with NB/Cur, up-regulation of the expression level of phosphorylated JNK and down-regulation of the expression level of phosphorylated ERK and Akt contributed to A375 cells apoptosis. Moreover, NB also potentiated Cur to trigger intracellular ROS overproduction and the DNA damage with up-regulation of the expression level of phosphorylated ATM, phosphorylated Brca1 and phosphorylated p53. The results indicate the combinational application potential of NB and Cur in treatments of cancers.

Comparative Analysis of Thermal Behavior, Isothermal Crystallization Kinetics and Polymorphism of Palm Oil Fractions

Thermal behavior of palm stearin (PS) and palm olein (PO) was explored by monitoring peak temperature transitions by differential scanning calorimetry (DSC). The fatty acid composition (FAC), isothermal crystallization kinetics studied by pulsed Nuclear Magnetic Resonance (pNMR) and isothermal microstructure were also compared. The results indicated that the fatty acid composition had an important influence on the crystallization process. PS and PO both exhibited more multiple endotherms than exotherms which showed irregular peak shapes. An increasing in cooling rate, generally, was associated with an increase in peak size. Application of the Avaimi equation to isothermal crystallization of PS and PO revealed different nucleation and growth mechanisms based on the Avrami exponents. PS quickly reached the end of crystallization because of more saturated triacylglycerol (TAG). The Avrami index of PS were the same as PO under the same isothermal condition at lower temperatrue, indicating that the crystallization mechanism of the two samples based on super-cooling state were the same. According to the polarized light microscope (PLM) images, crystal morphology of PS and PO was different. With the temperature increased, the structure of crystal network of both PS and PO gradually loosened.

Expression and purification of gp41-gp36 fusion protein and application in serological screening assay of HIV-1 and HIV-2

Recombinant fusion protein gp41-gp36 recognized by specific antibodies against HIV-1 and HIV-2, had been expressed and purified for the development of a serological screening kit in this study. Serological screening method by enzyme-linked immunosorbent assay (ELISA) with the purified gp41-gp36 was carried out to test the sensitivity and specificity of the protein by serum samples and reference panels from National Institute for the Control of Pharmaceutical and Biological Products (NICPBP), with the sensitivity and specificity found to be 100 and 99.0%, respectively. As the application was concerned, 42 HIV-1 positive,5 HIV-2 positive, and 300 negative human sera had been used, and reliable results had been obtained in comparison with other reference human immunodeficiency virus (HIV) ELISA kits in panels.

Proteomic Analysis of G2/M Arrest Triggered by Natural Borneol/Curcumin in HepG2 Cells, the Importance of the Reactive Oxygen Species-p53 Pathway.

Curcumin (Cur), an active ingredient from the rhizome of the plant Curcuma longa, has wide anticancer activities. However, due to its poor solubility and hence poor absorption, Cur has limited clinical applications. It is therefore important to develop an effective method to improve its absorption. Natural borneol (NB), a terpene and bicyclic organic compound, has been extensively used as a food additive, and our previous studies show that it can improve the uptake of Cur in cancer cells. However, the anticancer mechanism of NB/Cur remains unclear. In this study, the effects of NB/Cur on HepG2 cells were investigated by proteomic analysis. The results showed that 32 differentially expressed proteins identified by matrix assisted laser desorption ionization time-of-flight mass spectrometry were significantly changed after NB/Cur treated HepG2 cells for 24 h. Moreover, 17 proteins increased and 12 proteins decreased significantly. Biological progress categorization demonstrated that the identified proteins were mainly associated with cell cycle and apoptosis (28.1%). Subcellular location categorization exhibited that the identified proteins were mainly located in nucleus (28.1%) and mitochondrion (21.9%). Among of all proteins, we selected three differential proteins (hnRNPC1/C2, NPM, and PSMA5), which were associated with the p53 pathway. Down-regulation of hnRNPC1/C2 and NPM contributed to the enhancement of phosphorylated p53. Activated p53 and down-regulation of PSMA5 resulted in an increase in p21 protein. Further studies showed that NB/Cur induced reactive oxygen species (ROS) generation, indicating that ROS might be upstream of the G2/M arrest signaling pathway. In summary, the results exhibited the whole proteomic response of HepG2 cells to NB/Cur, which might lead to a better understanding of its underlying anticancer mechanisms.

Formation of β-cyclodextrin inclusion enhances the stability and aqueous solubility of natural borneol.

UNLABELLED The aims of this study were to optimize the preparation conditions of natural borneol/β-cyclodextrin (NB/β-CD) inclusion complex by ultrasound method, and to investigate its improvement of stability and solubility. The complex was characterized by different various spectroscopic techniques including Fourier transform infrared spectroscopy, X-ray diffractometry, and differential scanning calorimetry. The results demonstrate that NB could be efficiently loaded into β-CD to form an inclusion complex by ultrasound method at a molar ratio of 1: 1and mass ratio of 1: 6. The complex exhibited different physicochemical characteristics from that of free NB. Typically, formation of β-CD inclusion significantly enhanced the stability and aqueous solubility of NB. PRACTICAL APPLICATION Natural borneol (NB) has the potential to be widely used in the fields of medical and functional food, due to its specificity. However, the disadvantages of unstability in the preparation and storage process due to its easy sublimation and the low water solubility limit its application. This research provides an effective way to improve the solubility and stability of NB by preparing NB/β-CD inclusion complex. Furthermore, theoretical basis is also provided for the application development of NB.