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Biomedical subjects

F Fábián

Publications and source records attributed to F Fábián.

At least 19 recordsLinked to original sources
PubMed1993

Is an amphiphilic region responsible for the haemolytic activity of Bacillus thuringiensis toxin?

The amino acid sequence of the 27 kDa protein responsible for the haemolytic activity of Bacillus thuringiensis subsp. israelensis toxin has been analysed by secondary structure prediction, helical wheel/net diagrams and molecular mechanics calculations. We found that segment 116-126 presumably forms a strongly amphiphilic alpha-helix. This is supported by the findings that the synthesized segment 116-126 (a) has a significant alpha-helical content in water, and (b) displays an in vitro haemolytic activity comparable to that of bee venom peptide melittin. As segment 116-126 is present in the haemolyzing, but not present in the non-haemolyzing proteins from B. thuringiensis toxins, we suggest that this segment is responsible for the lytic potential of the B. thuringiensis subsp. israelensis protein.

Amino Acid Sequence↗
PubMed1993

Responses to continuous and discontinuous NaCl stress of long-term cultured rice (Oryza sativa L.) cells.

Rice (Oryza sativa L.) cells, grown under a continuous stress of 1.5% NaCl, produced a homogeneous mass of dry, compact, nodular callus with high regeneration potential, typical of embryogenic cultures. When transferred and subcultured in conditions without salt, the pre-adapted cells underwent several changes, leading to the formation of heterogeneous populations that comprised different cell types. This newly formed callus, in the 6-month period without salt stress, resembled cell populations of the untreated cultures. These cells are characterized by fast growth, high water content, friable texture, high salt sensitivity and low culture response. They also produce a protein pattern in the SDS-PAGE analysis, that differs from that of cells cultured under the continuous salt stress. This observation indicates that different salt stress regimes induced different responses in the cultured cells in rice.

Adaptation, Physiological↗
PubMed1981

Beta2-microglobulin-containing IgG complexes in sera and synovial fluids of rheumatoid arthritis and systemic lupus erythematosus patients.

The occurrence and composition of complexed beta2-microglobulin (beta2m) in sera and synovial fluids of rheumatoid arthritis and systemic lupus erythematosus patients and control persons was investigated. Beta2m-containing complexes were detected in immune complex (IC)-enriched fractions isolated by precipitation with 3% polyethylene glycol 6000, in the macromolecular peaks after Sephadex G-200 gel filtration, and in IC desorbed from solid-phase Clq. Beta2m complexes were demonstrated also after precipitation of redissolved PEG-insoluble material by anti-human beta2m serum or isolation of the complexes by use of Sephadex-anti-beta2m. IgG was co-isolated with beta2m on Sephadex-anti-beta2m and free beta2m inhibited the binding of IgG to Sephadex anti-beta2m, indicating that IgG was present in the complexed beta2m. Analysis by SDS-polyacrylamide gradient electrophoresis under reducing conditions indicated that the purified beta2m complexes contained IgG and beta2m.

Antigen-Antibody Complex↗
PubMed1978

Isolation of the C-terminal peptides of rabbit skeletal myosin.

Purified LMM and its tryptic fragments (LF-1, LF-2 and LF-3) were treated with carboxypeptidase-A and the liberated amino acids were identified by thin layer ion-exchange charomatography. In each protein the only detectable amino acid was leucine. From the total tryptic digest of LMM the C-terminal leucine containing peptides were isolated. Two peptides were found with the following amino acid composition: asx1, g1x6, ala1, leu3, and g1n2-3, leu1, respectively. We obtained the same two peptides from the total tryptic digest of LF-3. We conclude that the C-terminal amino acid of the myosin heavy chain is leucine rather than isoleucine as suggested earlier. Heterogeneity of isolated C-terminal peptides might indicate a heterogeneity in the myosin heavy chains.

Amino Acid Sequence↗
PubMed1977

18O-exchange catalyzed by myosin, heavy meromyosin, heavy meromyosin subfragment 1 and their complexes with actin.

Myosin, HMM and HMM S1 catalyze 18O-exchange between P1 and H218O of the medium at an intermediate stage of ATP hydrolysis ("intermediate 18O-exchange") in the presence of Mg2+. Natural complexes of actomyosin and acto-HMM S1 do not catalyze intermediate 18O-exchange but facilitate "direct" or "medium" 18O-exchange (KH2P18O4 in equilibrium H2O) even without ATP. Reconstituted complexes of actomyosin, acto-HMM, acto-HMM S1, PABC-HMM S1, congo-myosin and TNP-myosin do not catalyze direct 18O-exchange in the presence of Mg2+ and absence of ATP. From the data obtained a hypothetical sequence of phosphorylation and 18O-exchange reactions in myofibril action has been suggested.

Actins↗
PubMed1977

Investigation of peptides containing half-cystine in pig pancreas amylase.

Sequence analysis of the carboxymethyl-cystein-containing tryptic peptides isolated after the total reduction and carboxymethylation of pig pancreas amylase has shown that the half-cystine-containing tryptic peptides of the isozymes have identical sequences. The fact that 10 tryptic peptides containing carboxymethyl-cystein could be isolated, supports the generally accepted view that pig pancreas amylase contains single polypeptide chain.

Amino Acid Sequence↗