Tom70 mediates Sendai virus-induced apoptosis on mitochondria.

Unlabelled: Virus infection triggers immediate innate immune responses. Apoptosis represents another effective means to restrict virus invasion, besides robust expression of host cytokines and chemokines. IRF3 was recently demonstrated to be indispensable for Sendai virus (SeV)-induced apoptosis, but the underlying mechanism is not fully understood.

Studies on the temperature effect on bacteriorhodopsin of purple and blue membrane by fluorescence and absorption spectroscopy.

Fluorescence and absorption spectra were used to study the temperature effect on the conformation of bacteriorhodopsin (bR) in the blue and purple membranes (termed as bRb and bRp respectively). The maximum emission wavelengths of tryptophan fluorescence in both proteins at room temperature are 340 nm, and the fluorescence quantum yield of bRb is about 1.4 fold higher than that of bRp.

Six specific lysine residues are crucial in maintaining the structure and function of soluble manganese stabilizing protein.

When manganese stabilizing protein (MSP) was treated with 0.5 mM N-succinimidyl propionate (NSP), the rebinding ability and oxygen-releasing capabilities of the modified MSP were not altered, in spite of changes of MSP surface Lys residues. Furthermore, far-ultraviolet circular dichroism and intrinsic fluorescence spectra analysis revealed that 0.

Folding studies of two hydrostatic pressure sensitive proteins.

High hydrostatic pressure combined with various spectroscopies is a powerful technique to study protein folding. An ideal model system for protein folding studies should have the following characteristics. (1) The protein should be sensitive to pressure, so that the protein can be unfolded under mild pressure.

Positive charges on lysine residues of the extrinsic 18 kDa protein are important to its electrostatic interaction with spinach photosystem II membranes.

To determine the contribution of charged amino acids to binding with the photosystem II complex (PSII), the amino or carboxyl groups of the extrinsic 18 kDa protein were modified with N-succinimidyl propionate (NSP) or glycine methyl ester (GME) in the presence of a water-soluble carbodiimide, respectively. Based on isoelectric point shift, 4-10 and 10-14 amino groups were modified in the presence of 2 and 4 mM NSP, respectively. Similarly, 3-4 carboxyl groups were modified by reaction with 100 mM GME.

An oligonucleotide microarray for microRNA expression analysis based on labeling RNA with quantum dot and nanogold probe.

MicroRNAs (miRNAs) play important regulatory roles in animals and plants by targeting mRNAs for cleavage or translational repression. They have diverse expression patterns and might regulate various developmental and physiological processes. Profiling miRNA expression is very helpful for studying biological functions of miRNAs.

Pressure equilibrium and jump study on unfolding of 23-kDa protein from spinach photosystem II.

Pressure-induced unfolding of 23-kDa protein from spinach photosystem II has been systematically investigated at various experimental conditions. Thermodynamic equilibrium studies indicate that the protein is very sensitive to pressure. At 20 degrees C and pH 5.

Detection of tumor marker CA125 in ovarian carcinoma using quantum dots.

Semiconductor quantum dots (QDs) offer several advantages over organic dyes in fluorescence-imaging applications, such as higher quantum yield, exceptional photostability, and a narrow, tunable, and symmetric emission spectrum. To explore whether QDs could specifically and effectively label tumor markers and be used in immunohistochemistry as a novel type of fluorescent probe, we used quantum dots with maximum emission wavelength 605 nm (QD605) to detect the ovarian carcinoma marker CA125 in specimens of different types (fixed cells, tissue sections, and xenograft piece). Additionally, we compared the photostability of QD signals with that of a conventional organic dye, FITC.

Colorimetric detection of protein microarrays based on nanogold probe coupled with silver enhancement.

This work presents a method for analyzing protein microarrays using a colorimetric nanogold probe coupled with silver enhancement (gold-silver detection). In this method, the gold nanoparticles were introduced to the microarray by the specific binding of the gold-conjugated antibodies or streptavidins and then coupled with silver enhancement to produce black image of microarray spots, which can be easily detected with a commercial CCD camera. The method showed high detection sensitivity (1 pg of IgG immobilized on slides or 2.

[Thermodynamic and kinetic analysis of unfolding of P23k protein isolated from spinach photosystem II].

The unfolding of 23kD (P23k) protein isolated from spinach photosystem II particle was studied by high pressure and fluorescence spectroscopy. The thermal equilibrium study indicated that the protein could be totally unfolded by 180 or 160 MPa at 20 degrees C and 3 degrees C, respectively. The standard free energy and standard volume change of the protein for unfolding at 20 degrees C is 23.

The assignment of the reactive sites of the double-headed arrowhead proteinase inhibitor A and B.

The arrowhead proteinase inhibitor A and B (APIA and APIB) are double-headed and multifunctional. Both their primary structure and cDNA sequence have been elucidated. To locate the possible reactive site residues Lys(44), Arg(76) and Arg(87) of APIB predicted according to the sequence comparison with other proteinase inhibitors, the above residues were substituted with Pro by site-directed mutagenesis respectively, and the mutated genes were expressed in the yeast secretion system.

Participation of Water in the Binding of Estrogen Receptor with Estrogen Responsive Element in vitro.

Many reports have showed that bound water was involved in the interaction between/among the macromolecules. However, it has not been reported whether bound water is also involved in the binding of trans-factors and cis-elements in the regulation of the eukaryotic gene trans-cription or not. Preliminary studies have been made on the effect of bound water on the binding of estrogen receptor with estrogen responsive element in vitro.

Effect of Calcium Ion on Conformation of Horseradish Peroxidase Isoenzyme C.

Horseradish peroxidase isoenzyme C without ligand [apo-HRP(C)] was studied by fluorescence spectroscopy in this paper. It was observed: 1. there was a distinct Tyr fluorescence in the intrinsic fluorescence of apo-HRP(C), which was seldom observed in other "B" proteins; 2.

High Immunogenicity of the Pressure-inactivated Virus.

Effects of high hydrostatic pressure on the activity of infectious bursal disease virus (IBDV) was described. The infectivity of IBDV decreased with the increasing of pressure and pressurizing time and may be completely lost, indicated by the tests with chicken embryo fibrablast cell and young chicken as models. How-ever, pressure-inactivated IBDV still remained high immunogenicity and might induce high levels of protecting serum antibody.

Effect of High Hydrostatic Pressure on Activity of Restriction Endonucleases.

The effect of high hydrostatic pressure on the activities of type II restriction enzymes HindIII and XbaI in digesting plasmid pSPORT1 was studied. The endonuclease activity of HindIII and XbaI at 37 degrees were gradually inhibited by increasing pressure and completely inhibited at 200 and 180 MPa, respectively. No obvious irreversible effect was observed for HindIII after suffering high pressure, while a considerable irreversible inactivation was observed for XbaI.

An Emerging Field in Bioscience High Hydrostatic Pressure Study.

The goal of this mini review is to explain how hydrostatic pressure acts on bio-macromolecules(mainly on protein), giving some basic knowledge. Moreover, it will be shown that high pressure is a powerful tool both for the study of bio-macromolecules such as protein conformation, protein-protein (or protein-nucleic acid, or protein-ligands) interactions and the modulation of enzymatic activity etc. and for study of biotechnological application.

Conformation nearby Trp residues of APIA and APIB modulates the inhibitory specificity of the protease.

The relationship between the micro-environment of the two tryptophan residues and the inhibitory specificity of arrowhead protease inhibitors A and B (APIA and APIB) was studied by mutagenesis and fluorescence spectroscopy. The environment of the two Trp residues at positions 93 and 122 in APIB is more hydrophobic than in APIA. Study after substitution of Trp with Ala revealed that the environment of Trp(122) is more hydrophobic than that of Trp(93).

Comparison of the Catalytic Domains of Collagenase-1 and Stromelysin-1.

The catalytic domains of two matrix metalloproteinases--collagenase-1 and stromelysin-1 have been studied by means of fluorescence spectroscopy and high hydrostatic pressure. The hydrophobic fluorescence probe ANS could bind to stromelysin-1, with a dissociation constant of 26.3 &mgr;mol/L, but could not bind to collagenase-1, indicating that there exists a hydrophobic site on the surface of stromelysin-1.

A Vaccine to Coxsackievirus Prepared by High Pressure.

Effects of high hydrostatic pressure on infectious and immune activity of coxsackievirus group B (CVB) was described. CVB was completely inactivated at 230 MPa pressure and -16 degrees. The inactivated viruses remained highly immunogenic and induced CVB-specific serum antibody at a concentration as low as 1:1 500.

Barotolerant E.coli Induced by High Hydrostatic Pressure.

The barotolerant E.coli TG1P, DH5alphaP, HB101P were obtained from TG1,DH5alpha, HB101 after treatment with high hydrostatic pressure, and the survival rates of the formers raised 2--3 magnitude, from 1.06x10(-6), 2.

[Application of quantum dot to life science].

As an eminent representation of nanotechnology, quantum dot (semiconductor nanocrystal) has caught great interests of scientists in physics, chemistry, material science, and biology extensively. Although its application to life science has just been explored, valuable progresses have been achieved in both biomacromolecule labeling and coding recently. The progress in quantum dot synthesis, its spectroscopic and photoelectronic properties, and its potential application to life science are reviewed.