Tsong-Rong Yan

Characterization of a partially purified bacteriocin, Fermentcin B, from Lactobacillus fermentum

A bacteriocin, Fermentcin B produced by Lactobacillus fermentum, was identified from the inhibitory products of twenty-nine mesophilic lactic acid bacteria. It has a bactericidal activity with a narrow inhibitory spectrum. The bacte-riocin is heat stable at 100° 30 min and stable in pH range of 3.0 to 8.0. Fermentcin B lost its activity after treatment with a-chymotrypsin, proteinase-K, and amyloglucosidase.

Synthesis of alkyl β-glucosides from cellobiose with Aspergillus niger β-glucosidase II

An extracellular β-glucosidase II of Aspergillus niger catalyzed the synthesis of methyl β-glucoside and ethyl β-glucoside with 5.0% (v/v) cellobiose as glucosyl donor in a biphasic media containing 20% (v/v) methanol and 30% (v/v) ethanol, respectively. The maximum yield of methyl β-glucoside and ethyl β-glucoside was 83% (mol/mol; 12 mg/ ml) and 53% (mol/mol; 5.5 mg/ml), based on cellobiose consumed.

Synthesis of cello-oligosaccharides from cellobiose with β-glucosidase II from Aspergillus niger

An extracellular β-glucosidase II of Aspergillus niger catalysed the synthesis of cello-oligosaccharides from cellobiose (15%, w/v). The enzyme was stable at and below 4°C for at least 230 days and also stable at 30°C with the presence of 2.0% (w/v) cellobiose. The maximum yield of cello-oligosaccharides was about 30% (mol/mol), based on cellobiose (130 mg/mL) consumed.

APPLYING THE QUARTZ CRYSTAL MICROBALANCE TECHNIQUE TO DETECT THE EPITHELIAL CELL TIGHT JUNCTION INTEGRALITY OF Caco-2 CELLS

This paper describes a method that utilizes the quartz crystal microbalance (QCM) technique to measure the tight junction of the Caco-2 cell. The Caco-2 cells are placed on the QCM surface for cell growth and tight junction measurements. We found that the QCM resonance frequency changes less when a better tight cell junction is formed. The quantity of QCM frequency change is less than 100 Hz as the tight junction cell integrality is completed up to 15 days. The QCM and traditional detection system transepithelial electrical resistance were similar as the cell growth affects the two systems over time.

Detecting cells on the surface of a silver electrode quartz crystal microbalance using plasma treatment and graft polymerization

This paper utilizes a silver electrode quartz crystal microbalance (QCM) mass sensor to detect the physiology of cells. This study also investigates the plasma surface modification of silver electrode QCMs through deposition of hexamethyldisilazane (HMDSZ) films as a protection film. To improve the cell growth, this paper also performs post-treatments by surface-grafting acrylic acid (AAc), acrylamide (AAm), and oxygen plasma treatment onto the QCM electrodes. Experimental results indicate that plasma deposition is a useful technique to protect the surface of silver electrodes. This technique extends the unpeeling time of silver electrodes from 1 to 7 days. The hydrophilic silver electrode QCM surface modified by AAm exhibited a better storage time effect than other post-treatments.

MATTERS NEEDING ATTENTION FOR APPLYING THE QUARTZ CRYSTAL MICROBALANCE TECHNIQUE TO DETECT THE CELL MORPHOLOGY

Using quartz crystal microbalance (QCM) to design a cell detection platform is an important application of QCM. In the process of system design and application, there still have some points, which are easily overlooked or are not understood by researchers. Most of the problems can be separated into three types. One is the cell culture environment conditions that affect the system signals, another is the system unification or lack of communication over regulations, and the other is the over-analysis of the experimental data.

IMPROVE THE DATA ACQUISITION SYSTEM OF A QCM SENSOR BY INCREASING THE SAMPLING RATE OF FREQUENCY AND AMPLITUDE

Quartz crystal microbalance (QCM) has been constructed and used for chemical sensing and biochemical detecting. Frequency shift has a relation with mass changed in the gaseous condition. However, the velocity, density, and viscosity also cause frequency changed in liquid solution. We develop a new method and system to investigate the variable value of amplitude and frequency from the oscillator of quartz. In this system, piezoelectric quartz crystal (10 MHz, AT-cut) with gold electrodes was mounted under liquid solution. Crystal was exposed to the different concentrations of glucose and sodium chloride solution. The results show that the ramp-up speed of amplitude was faster as frequency in the alternative state. We figure out the largest skew through the differential curve of amplitude in different solutions. The dramatic results give a QCM more meanings to be a biochemistry detecting utility.

Catalytic properties of a transglucosidase from Aspergillus niger CCRC 31494

SummaryA transglucosidase of Aspergillus niger had hydrolysis and transglucosylation activities toward several types of malto- and isomalto-oligosaccharides. The activity was competitively inhibited by glucose and mannose but was not inhibited by galactose and fructose. The Kis of glucose and mannose were 12.9 mM and 75.9 mM, respectively. The enzyme was stable in storage at -20 °C with 60% (v/v) glycerol and 4 °C for at least 40 days.

A Quartz Crystal Microbalance Cell-Culture Incubator System

A biosensor consists of the immobilized biological recognition element (e.g. antibody, DNA, enzyme, receptor, microorganism, or cell) in intimate contact with a signal transducer (electrochemical, optical, thermal, or acoustic signal) that together permit analysis of chemical properties or quantities. The quartz crystal microbalance (QCM) technique has traditionally been used to monitor mass or thickness of thin films deposited on surfaces either in a gaseous or in a liquid environment. More recently this method has been extended to investigate the process of attachment and spreading of mammalian cells onto the solid electrode of the quartz sensor. Real-time measurements of the shift in resonance frequency and energy dissipation due to changes in mass and viscoelastic properties give quantitative information about the state of the cell adhesion process. We show that the QCM technique is a sensitive method not only to measure quasi-static cell adhesion processes but also dynamic changes of mechanical cell properties. In this innovation, a new cell-based QCM biosensor system which can real-time monitor the adhesion and growth of animal cells will be developed. A cell culture unit for cell to adhesion, spreading and growth will be designed and fabricated. A QCM chip sensor can measure the frequency, amplitude, trans-epithelial resistance, and A/C impedance. These materials were all fabricated under the cell unit to monitor cell growth conditions. An environment control system can offer a constant temperature, a permanent CO2 concentration and a nutrition feed fluid system. Finally, a quartz crystal microbalance cell-culture incubator system can provide the recognizing cell-substrate adhesion and established as a tool for drug discovery and even drug evaluation.