Investigation of the interactions between methylene blue and intramolecular G-quadruplexes: an explicit distinction in electrochemical behavior.

G-quadruplex sequences exist in eukaryotic organisms and prokaryotes, and the investigation of the interactions between G-quadruplexes and small molecule ligands is important for gene therapy, biosensor fabrication, fluorescence imaging and so on. Here, we investigated the behaviour of methylene blue (MB), an electroactive molecule, in the presence of different intramolecular G-quadruplexes by an electrochemical method using a miniaturized electrochemical device based on its intrinsic electrochemical properties. Although the effects of MB on different intramolecular G-quadruplex structures are not obvious by circular dichroism spectroscopy, distinct differences in the binding affinities of MB with different intramolecular G-quadruplexes were quickly and easily observed by an electrochemical technique.

Effect of Modified Roux-en-Y Gastric Bypass Surgery on GLP-1, GIP in Patients with Type 2 Diabetes Mellitus.

The type 2 diabetes mellitus (T2DM) is one of the most serious diseases that threaten public health. Modified gastric bypass surgery has been applied to the treatment of T2DM patients in the 1990s, but the therapeutic mechanism to this function is still unclear. The aim of this study was to further clarify the effect and the mechanism of modified gastric bypass surgery on glucose metabolism in patients with T2DM.

A smart tailor-made G-clip reporter for sensitive detection of G-triplet-containing sequences.

Taking advantage of the intrinsic characteristics of G-triplet-containing sequences, a pioneering tailor-made clip-like reporter containing three-fourths of a G-quadruplex is established. The reporter can clip the G triplet in the target sequence through a recognition process to form a complete G-quadruplex structure.

Comparison of different gastric bypass procedures in gastric carcinoma patients with type 2 diabetes mellitus.

Aim: To determine the effect of different Roux-en-Y gastric bypass procedures in gastric carcinoma patients with type 2 diabetes mellitus.

Methods: A retrospective analysis of the clinical data of 54 patients with gastric cancer and type 2 diabetes mellitus treated in the Department of General Surgery from January 2006 to June 2013 was conducted. The patients underwent gastrectomy using different Roux-en-Y gastric bypass procedures (traditional, n = 26; modified, n = 28).

A G-quadruplex based platform for label-free monitoring of DNA reaction kinetics.

Research on the kinetic characteristics and mechanisms of DNA reactions is crucial for bioengineering and biosensing. A G-quadruplex, which can form a peroxidase-mimicking DNAzyme with hemin, was for the first time used to establish a versatile platform for kinetic investigations on DNA reactions. G-quadruplex sequence EAD2 was incorporated into the corresponding nucleic acid reaction as product.

Methylene blue as a G-quadruplex binding probe for label-free homogeneous electrochemical biosensing.

Herein, G-quadruplex sequence was found to significantly decrease the diffusion current of methylene blue (MB) in homogeneous solution for the first time. Electrochemical methods combined with circular dichroism spectroscopy and UV-vis spectroscopy were utilized to systematically explore the interaction between MB and an artificial G-quadruplex sequence, EAD2. The interaction of MB and EAD2 (the binding constant, K ≈ 1.

Reporter-triggered isothermal exponential amplification strategy in ultrasensitive homogeneous label-free electrochemical nucleic acid biosensing.

A simple and novel reporter-triggered isothermal exponential amplification reaction (R-EXPAR) integrated with a miniaturized electrochemical device was developed, which achieved excellent improvement (five orders of magnitude) of sensitivity toward reporter, G-quadruplex. This R-EXPAR strategy has been successfully implemented to construct a homogeneous label-free electrochemical sensor for ultrasensitive DNA detection.

Novel homogeneous label-free electrochemical aptasensor based on functional DNA hairpin for target detection.

We first developed a label-free and immobilization-free homogeneous electrochemical aptasensor, which combined a smart functional DNA hairpin and a designed miniaturized electrochemical device. Cocaine was chosen as a model target. The anticocaine aptamer and peroxidase-mimicking DNAzyme were integrated into one single-stranded DNA hairpin.

Global transcriptional profiling in porcine mammary glands from late pregnancy to peak lactation.

Sow milk yield and quality is crucial for the survival and growth of piglets. To understand the molecular mechanisms of lactogenesis and lactation, mammary tissue samples were taken from six sows at -17(±2), 1 and 17(±2) days relative to parturition. Mammary tissues from two sows in the same stage were used to extract RNA, which were subsequently pooled in equal amounts.

A label-free aptasensor for the sensitive and specific detection of cocaine using supramolecular aptamer fragments/target complex by electrochemical impedance spectroscopy.

A simple and label-free aptasensor for sensitive and specific detection of cocaine was developed by measuring the change in electrochemical impedance spectra (EIS), based on the formation of a supramolecular aptamer fragments/substrate complex. An anticocaine aptamer was divided into two fragments, Cx and Cy. Three different sensing interfaces, called Au/Cx5S/MCE, Au/Cy3S/MCE and Au/Cy5S/MCE, were fabricated by immobilizing Cx or Cy on a gold electrode through modifying their 5' or 3' end with a thiolated group followed by the treatment with mercaptoethanol (MCE).

An electrochemical aptasensor based on enzyme linked aptamer assay.

An aptamer is an artificial functional oligonucleic acid, which can interact with its target molecule with high affinity and specificity. Enzyme linked aptamer assay (ELAA) is developed to detect cocaine using aptamer fragment/cocaine configuration based on the affinity interaction between aptamer fragments with cocaine. The aptasensor was constructed by cleaving anticocaine aptamer into two fragments: one was assembled on a gold electrode surface, while the other was modified with biotin at 3'-end, which could be further labelled with streptavidin-horseradish peroxidase (SA-HRP).

Identification of the VIL2 enhancer in human embryonic kidney cells.

We previously demonstrated that the VIL2 -87/+134 region exhibited promoter activity in some human cells, and a region further upstream of this promoter might contain an enhancer. However, the properties and location of this VIL2 enhancer remain unclear. In this study, we cloned the VIL2 -1541/-706 segment and investigated its transcriptional regulatory properties via luciferase assays in transiently transfected HEK-293 cells (human embryonic kidney cells).

Transplantation of microencapsulated umbilical-cord-blood-derived hepatic-like cells for treatment of hepatic failure.

Aim: To investigate intraperitoneal transplantation of microencapsulated hepatic-like cells from human umbilical cord blood for treatment of hepatic failure in rats.

Methods: CD34+ cells in umbilical cord blood cells were isolated by magnetic cell sorting. In the in vitro experiment, sorted CD34+ cells were amplified and induced into hepatic-like cells by culturing with a combination of fibroblast growth factor 4 and hepatocyte growth factor.

[Research progress in ectopic grafting of testicular tissues].

Since Nature published the first report in 2002 on using immunodeficient mice as recipients and allogeneous or heterogeneous testes as donor tissues to study the ectopic development of spermatogenic cells, the technique has been widely applied in various species (including human). In comparison with other in vitro maturation methods for male germ cells, testicular allografting or xenografting technique has such advantages as similar environment for the development of germ cells in physiological conditions, and better reproducibility. Up to now, sperm has been successfully produced by this technique from the testicular tisues of the immature mouse, hamster, cat, rabbit, pig, goat, bovine and rhesus monkey, and their offspring have even been generated by ICSI technique using the mouse and rabbit sperm derived from testis grafts.

Development of neonatal mouse and fetal human testicular tissue as ectopic grafts in immunodeficient mice.

Aim: To investigate the stepwise development and germ cell gene expression in allografted neonatal mouse testes and the differentiation of immature human testicular cells in xenografted human testes.

Methods: Immunodeficient nude mice were used as hosts for allografting of neonatal mouse testes and xenografting of human fetal testicular tissues. Stepwise development and stage-specific gene expression of germ cells in allografts were systematically evaluated and parallel compared with those in intact mice by periodically monitoring the graft status with measurement of graft weight, histological analysis and determination of five stage-specific genes.

[Conversion of human umbilical cord blood-derived cells into hepatocyte-like cells in a culture system mimicking hepatic injury].

Objective: To explore the effect of the microenvironment induced by damaged mouse hepatic cells on the conversion of human umbilical cord blood-derived cells into hepatocyte-like cells.

Methods: A hepatic injury-like microenvironment was mimicked using carbon tetrachloride damaged mouse hepatic cells, where mononuclear cells (MNC) from human umbilical cord blood were cultured in a compartment separated by trans-well membrane. Histochemical staining, reversed transcription-polymerase chain reaction (RT-PCR) and gene sequencing were performed for the information on the conversion of human umbilical cord blood MNC.

[Establishment of animal model for in vitro spermatogenesis by heterotopic grafting of neonatal mouse testis].

Objective: To establish an in vitro model for the development of mouse spermatogenic cells into sperm by using the immunodefective mouse as the incubator.

Methods: Tissue grafting was performed using testis from 1-2 days old Kun-ming mice as donor tissue and immunodefective mice as recipients; the expression of TESK1 mRNA in grafts was determined by RT-PCR and the spermatogenesis further observed with histological analysis of grafts.

Results: Molecular biological and histological analyses showed that grafts post-grafting not only expressed TESK1 mRNA as in normal mouse testis, but also exhibited similarities in the structure of seminiferous tubules and component of spermatogenic cells, including sperms.