Proliferation, migration, and resistance to oxidative and thermal stresses of HT1080 cells with knocked out genes encoding Hsp90α and Hsp90β.

Heat shock protein 90 (Hsp90) fulfils essential housekeeping functions in the cell associated with the folding, stabilization, and turnover of various proteins. In mammals, there exist two Hsp90 isoforms, stress-inducible Hsp90α and constitutively expressed Hsp90β. In an attempt to identify cellular processes dependent on Hsp90α and Hsp90β, we generated a panel of clones of human fibrosarcoma HT1080 cells with the knocked out HSP90AA1 or HSP90AB1 genes encoding, respectively, Hsp90α and Hsp90β.

The effect of apolipoprotein A-I and perfluorocarbon emulsion on the production of specific antibodies in mice.

Adjuvants are often required to improve the potentially low immunogenicity of vaccines. In this study, it is proposed to use an emulsion based on fluorocarbons as an adjuvant. Since this emulsion adsorbs only a small range of proteins, apolipoprotein A-I (ApoAI) was used as an anchor.

Predominant synthesis of giant myofibrillar proteins in striated muscles of the long-tailed ground squirrel Urocitellus undulatus during interbout arousal.

Molecular mechanisms underlying muscle-mass retention during hibernation have been extensively discussed in recent years. This work tested the assumption that protein synthesis hyperactivation during interbout arousal of the long-tailed ground squirrel Urocitellus undulatus should be accompanied by increased calpain-1 activity in striated muscles. Calpain-1 is known to be autolysed and activated in parallel.

A 2,5-Dihydroxybenzoic Acid-Gelatin Conjugate Inhibits the Basal and Hsp90-Stimulated Migration and Invasion of Tumor Cells.

The extracellular cell surface-associated and soluble heat shock protein 90 (Hsp90) is known to participate in the migration and invasion of tumor cells. Earlier, we demonstrated that plasma membrane-associated heparan sulfate proteoglycans (HSPGs) bind the extracellular Hsp90 and thereby promote the Hsp90-mediated motility of tumor cells. Here, we showed that a conjugate of 2,5-dihydroxybenzoic acid with gelatin (2,5-DHBA-gelatin), a synthetic polymer with heparin-like properties, suppressed the basal (unstimulated) migration and invasion of human glioblastoma A-172 and fibrosarcoma HT1080 cells, which was accompanied by the detachment of a fraction of Hsp90 from cell surface HSPGs.

Cell surface heparan sulfate proteoglycans are involved in the extracellular Hsp90-stimulated migration and invasion of cancer cells.

The extracellular heat shock protein 90 (Hsp90) is known to participate in cell migration and invasion. Recently, we have shown that cell surface heparan sulfate proteoglycans (HSPGs) are involved in the binding and anchoring of extracellular Hsp90 to the plasma membrane, but the biological relevance of this finding was unclear. Here, we demonstrated that the digestion of heparan sulfate (HS) moieties of HSPGs with a heparinase I/III blend and the metabolic inhibition of the sulfation of HS chains by sodium chlorate considerably impair the migration and invasion of human glioblastoma A-172 and fibrosarcoma HT1080 cells stimulated by extracellular native Hsp90.

Protealysin is not Secreted Constitutively.

Background: Protealysin, a zinc metalloprotease of Serratia proteamaculans, is the prototype of a new group within the peptidase family M4. Protealysin-like proteases (PLPs) are widely spread in bacteria but are also found in fungi and archaea. The biological functions of PLPs have not been well studied, but published data showed the involvement of enzymes of this group in the interaction of bacteria with higher organisms, and most likely in the pathogenesis.

A sensitive and specific lateral flow assay for rapid detection of antibodies against glycoprotein B of Aujeszky's disease virus.

A direct double antibody lateral flow assay (DDA-gB-LFA) for the detection of antibodies against the glycoprotein B (gB) of Aujeszky's disease virus (ADV) in swine sera was developed. A native ADV gB was used for the preparation of a conjugate with colloidal gold particles and the immobilization on the strip membrane. The gB purified from ADV virions by immunoaffinity chromatography retained its native epitope structure after adsorption on the nitrocellulose membrane and the surface of colloidal gold particles.

Cell surface heparan sulfate proteoglycans are involved in the binding of Hsp90α and Hsp90β to the cell plasma membrane.

Extracellular membrane-bound and secreted heat shock protein 90 (Hsp90) is known to be involved in cell motility and invasion. The mechanism of Hsp90 anchoring to the plasma membrane remains obscure. We showed that treatment of human glioblastoma A-172 and fibrosarcoma HT1080 cells with sodium chlorate, heparinase, and heparin causes a prominent loss of 2 Hsp90 cytosolic isoforms, Hsp90α and Hsp90β, from the cell surface and strongly inhibits the binding of exogenous Hsp90 to cells.

A 2,5-Dihydroxybenzoic Acid-Gelatin Conjugate: The Synthesis, Antiviral Activity and Mechanism of Antiviral Action Against Two Alphaherpesviruses.

Various natural and synthetic polyanionic polymers with different chemical structures are known to exhibit potent antiviral activity in vitro toward a variety of enveloped viruses and may be considered as promising therapeutic agents. A water-soluble conjugate of 2,5-dihydroxybezoic acid (2,5-DHBA) with gelatin was synthesized by laccase-catalyzed oxidation of 2,5-DHBA in the presence of gelatin, and its antiviral activity against pseudorabies virus (PRV) and bovine herpesvirus type 1 (BoHV-1), two members of the Alphaherpesvirinae subfamily, was studied. The conjugate produced no direct cytotoxic effect on cells, and did not inhibit cell growth at concentrations up to 1000 µg/mL.

Bacterial community structure and dissolved organic matter in repeatedly flooded subsurface karst water pools.

Bacterial diversity, community assembly, and the composition of the dissolved organic matter (DOM) were studied in three temporary subsurface karst pools with different flooding regimes. We tested the hypothesis that microorganisms introduced to the pools during floods faced environmental filtering toward a 'typical' karst water community, and we investigated whether DOM composition was related to floodings and the residence time of water in stagnant pools. As predicted, longer water residence consistently led to a decline of bacterial diversity.

Release of the glucose-regulated protein 94 by baby hamster kidney cells.

Glucose-regulated protein 94 (grp94) is a major component of the endoplasmic reticulum (ER) lumen of eukaryotic cells. We showed that grp94 is released from baby hamster kidney (BHK-21) cells into a serum-free medium. The exit of grp94 into the medium was not related to the protein discharge due to cell death and was independent of de novo protein synthesis.

Secretion of the heat shock proteins HSP70 and HSC70 by baby hamster kidney (BHK-21) cells.

The HSPs (heat-shock proteins) of the 70-kDa family, the constitutively expressed HSC70 (cognate 70-kDa heat-shock protein) and the stress-inducible HSP70 (stress-inducible 70-kDa heat-shock protein), have been reported to be actively secreted by various cell types. The mechanisms of the release of these HSPs are obscure, since they possess no consensus secretory signal sequence. We showed that baby hamster kidney (BHK-21) cells released HSP70 and HSC70 in a serum-free medium and that this process was the result of an active secretion of HSPs rather than the non-specific release of the proteins due to cell death.

Purification of the 90 kDa heat shock protein (hsp90) and simultaneous purification of hsp70/hsc70, hsp90 and hsp96 from mammalian tissues and cells using thiophilic interaction chromatography.

Heat shock proteins (HSPs) hsp70/hsc70, hsp90 and hsp96 were separated from mammalian cells and tissues on a gel obtained by the reaction of beta-mercaptoethanol with divinyl sulfone-activated Sepharose CL-6B (thiophilic gel or T-gel). Hsp90 revealed a much higher affinity towards the T-gel than the other HSPs. One-step thiophilic interaction chromatography of proteins resulted in a more than 80% purity and 85% yield of hsp90.

Barnase-barstar high affinity interaction phenomenon as the base for the heterogenous bioluminescence pseudorabies virus' immunoassay.

The effective new variant of "sandwich" bioluminescent enzyme immunoassay (BEIA) for the sensitive detection of glycoprotein B (gB) of pseudorabies virus (PrV) was presently developed. The high affinity interaction of barnase-barstar protein pair and photoprotein obelin as bioluminescent marker were for the first time successfully applied to BEIA development. Preliminary the two monoclonal antibodies, 11/5 and 34/2, were raised against gB for ELISA PrV detection.

Cell-binding properties of glycoprotein B of Aujeszky's disease virus.

The glycoprotein B (gB) of Aujeszky's disease virus (ADV) has a role in virus entry and cell-to-cell spread. In this report we examined the cell-binding properties of native ADV gB purified from the virus envelope by affinity chromatography. The binding of gB to the surface of susceptible cells BHK-21 and MDBK was specific, dose-dependent, and nearly saturable, which is characteristic of conventional receptor-ligand interactions.

Correct GPI-anchor synthesis is required for the incorporation of endoglucanase/glucanosyltransferase Bgl2p into the Saccharomyces cerevisiae cell wall.

The SSU21/MCD4 gene encodes an essential component of the glycosylphosphatidylinositol (GPI)-anchor synthesis pathway in Saccharomyces cerevisiae. Here we demonstrate that the ssu21 mutation affected the transport and the incorporation into the cell wall of the major non-GPI yeast cross-linker - endoglucanase/glucanosyltransferase Bgl2p. This mutation also led to a decrease in the levels of both known types of cell wall mannoproteins, those covalently linked with glucan and SDS-extractable proteins.