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Biomedical subjects

T M Jacob

Publications and source records attributed to T M Jacob.

At least 19 recordsLinked to original sources
PubMed1986

Purification of antibodies specific to a dinucleotide using the hapten bound to DEAE cellulose as an affinity column.

The dinucleotide dpTpA held electrostatically on DEAE cellulose was used as an affinity column for the purification of dpTpA specific antibodies. Chromatography of the gamma-globulin fraction from dpTpA specific antisera on this column resulted in the retention of dpTpA specific antibodies which were later eluted along with the bound dpTpA using 1M NaCl. Dextran coated charcoal was the method of choice for the dissociation and removal of dpTpA bound to the antibodies. This method may extend itself to the purification of antibodies specific for other oligonucleotides.

Antibodies↗
PubMed1986

The RNA binding subset of adenosine antibodies.

Hapten specific antibodies were elicited against adenosine-BSA conjugate (Ado-BSA) in rats. By radiohapten assay, two major populations of hapten specific antibodies were identified. They were directed against either adenosine trialcohol (Aox-red) or morpholino-adenosine (Morph-Ade). The association constant (Ka) for the 3H-Aox-red binding population was determined to be 1.02 X 10(7) M-1. Majority of the Aox-red specific antibodies were cross-reactive with Morph-Ade, but they did not cross-react at all with adenosine(A) or deoxyadenosine (dA). 3H-A binding subsets were actually Morph-Ade specific and constitute less than 10% of the hapten specific antibodies. The Ka value for the 3H-A binding was determined to be 4.5 X 10(6) M-1. A very minor and highly cross-reactive subset of Morph-Ade specific antibodies participate in RNA binding. Though a larger proportion of Morph-Ade specific antibodies interact with 3H-A, only a fraction of them bind to RNA. The extreme cross-reactivity and hence, the highly adaptive nature of the binding sites of the antibodies interacting with RNA, might be a stringent requirement for recognising adenine residues of nucleic acids in solution.

Adenosine↗
PubMed1986

Sequence specific antibodies to a deoxyribodinucleotide.

Antibodies were elicited in rabbits to the dinucleotide, dpTpA, conjugated to a carrier protein. Among a few deoxyribomono- and oligonucleotides tested for binding to the antibodies by nitrocellulose tilter binding assay, only dpTpA and dpTpA containing oligonucleotides showed binding. The inhibition of the binding of 3H-dpTpA to the antibodies by various nonradioactive mono- and oligonucleotides showed that the antibodies were sequence specific and recognized the whole molecule of dpTpA. dpTpA specific antibodies were purified by a two step affinity chromatography. By competition studies, it was found that the purified antibodies bound denatured DNA at dpTpA sequences. The antibodies did not bind RNA.

Antibodies↗
PubMed1985

Antibodies directed against guanylic acid and guanosine are nucleolus specific probes.

Purified antibodies against guanylic acid and guanosine binding to RNA at guanosine residues were used to probe human lymphocyte preparations by indirect immunofluorescence. Neither antibody gave any banding pattern with metaphase chromosomes but both showed binding to specific sites in the interphase nuclei. Evidence presented indicates that these sites are guanosine residues on rDNA transcripts at the nucleolar organizer regions.

Antibodies↗
PubMed1985

New model systems to study DNA-protein recognition mechanisms.

dpG antibodies were fractionated on a cellulose-double-stranded DNA column. The flow-through fraction bound denatured DNA but not double-stranded DNA (dsDNA). The dpG-eluted fraction bound dsDNA preferentially. The results show that proteins can recognise dpG in DNA by different mechanisms, some involving DNA unwinding.

Animals↗
PubMed1985

Characterization of adenosine-bovine serum albumin immunogen and its antibodies.

Antibodies to adenosine were elicited in rabbits using a conjugate of adenosine (periodate oxidized) and bovine serum albumin as immunogen. The conjugate was found to be of a higher molecular size than the original protein, apparently due to the cross-linking of albumin molecules by the dialdehydes generated during the periodate oxidation of adenosine. It produced high titres of antibodies, which were 400-fold more reactive to adenosine-trialcohol than to adenosine, when measured by a nitrocellulose filter assay. In addition, a specific elution procedure for the isolation of hapten-specific antibodies is described.

Adenosine↗
PubMed1984

Antibodies to guanosine. Fractionation and specificities.

Bovine serum albumin conjugates of guanosine prepared by the periodate method was used as immunogen to elicit guanosine antibodies in rabbits. The specificities of the antibodies were studied by the inhibition of their binding to [3H]Gox-red, [32P]DNA and [3H]RNA by related non-radioactive compounds. A population of antibodies is specific to Gox-red with an average association constant of around 10(7) M-1 at 4 degrees C. There are a population of antibodies which bind to [32P]ssDNA and [3H]RNA specifically at guanosine residues. RNA binding antibodies were separated into two populations by affinity chromatography.

Animals↗
PubMed1984

Antibodies to guanylic acid: fractionation and specificities.

Guanylic-acid-specific antibodies were elicited in rabbits, using as immunogen pG linked through 5'-phosphate to thyroglobulin. Specificity and affinity of antibodies to nucleotides, nucleosides, DNA, and RNA were studied by their binding to radioactive ligands and competition experiments. Guanylic-acid-specific antibodies do not bind to deoxyguanylic acid and have an average association constant of 10(7) M-1 at 4 degrees C. Binding of the antibodies to 3H-RNA is G-specific. The antibodies do not bind to 32P-ssDNA or 32P-dsDNA. The pG-specific antibodies could be separated into different fractions by affinity chromatography. These fractions, though specific to pG, differ in their cross-reactivities to nucleosides and nucleotides.

Animals↗
PubMed1984

Isolation and specificity of antibodies to uridine.

Antibodies to uridine were produced in rabbits using a conjugate of uridine (periodate oxidized) and bovine serum albumin as immunogen. The specificity of the antibodies was studied by estimating the inhibition of the binding of 3H-uridine-trialcohol to the antibodies by various non-radioactive related compounds, using a nitrocellulose filter assay. The antibodies were 1500-fold more reactive to the uridine-trialcohol than the parent nucleoside. They bound 3H-RNA at homologous base residues. The hapten specific antibodies were purified by affinity chromatography on a uridine-AH-Sepharose column.

Animals↗
PubMed1984

Specificity and purification of antibodies to adenylic acid.

Anti-adenylate antibodies were elicited in rabbits using a conjugate of adenylic acid and bovine serum albumin as immunogen. The specificity of the antibodies was determined by monitoring the inhibition of the binding of [3H]AMP to the antibodies by various nonradioactive nucleic acid components, using a nitrocellulose filter assay. The antibodies were found to be directed against the whole molecule of AMP. They were reactive to polyadenylic acid, RNA, and denatured DNA. The hapten-specific antibodies were isolated by employing an AMP-AH-Sepharose affinity column.

Adenosine Monophosphate↗
PubMed1982

Base specific binding of deoxyguanylate and deoxycytidylate antibodies to double stranded DNA.

Antibodies raised in rabbits against deoxyguanylate and deoxycytidylate bind to 3H-lambda double stranded DNA and the binding is base specific. The concentrations of antibody populations that bind to double stranded DNA are much less than those binding to denatured DNA. Due to their low concentrations, these antibodies were not detected in earlier studies. These antibodies are expected to be useful to probe the conformational flexibilities of double stranded DNAs.

Antibodies↗
PubMed1982

Isolation and Estimation of Cytokinins and Cytokinin-Containing Transfer RNAs from Cucumis sativus L. var. Guntur Seedlings.

N(6)-(Delta(2)-Isopentenyl) adenosine antibodies were used for the isolation of free cytokinins and cytokinin-containing tRNAs from parts of Cucumis sativus L. var. Guntur seedlings and for the estimation of cytokinins in them. Immobilized N(6)-(Delta(2)-isopentenyl) adenosine antibodies retained tRNAs containing N(6)-(Delta(2)-isopentenyl) adenosine and N(6)-(4-hydroxy-3-methylbut-2-enyl) adenosine with equal efficiencies. There were at least five cytokinins in the free form in cucumber seedlings. N(6)-(4-Hydroxy-3-methylbut-2-enyl) adenosine, N(6)-(Delta(2)-isopentenyl) adenosine, and N(6)-(Delta(2)-isopentenyl) adenine were present at least to the extent of 80, 23, and 9 nanograms, respectively, in the cotyledons and 40, 6, and 3 nanograms, respectively, in the decotyledonated seedlings per gram of tissue. Only two cytokinins were found in the tRNAs of cucumber cotyledons, namely N(6)-(Delta(2)-isopentenyl) adenosine and N(6)-(4-hydroxy-3-methylbut-2-enyl) adenosine in amounts of 12 and 318 nanograms, respectively, per gram of tissue. Immunoaffinity chromatographic analysis of radiolabeled aminoacyl tRNAs from cucumber cotyledons showed that tRNA(Phe) and tRNA(Tyr) contained cytokinins whereas tRNA(Ala) did not.

Journal Article↗
PubMed1981

Specificity of deoxycytidylate antibodies.

Antibodies to deoxycytidylate (dpC) were elicited in rabbits using a thyroglobulin (Tg) conjugate of dpC. The specificity of the antibodies was determined by measuring the inhibition of the binding of [3H]dpC to the antibodies by various non-radioactive nucleotides or derivatives. The antibodies were found to distinguish dpC from pC and DNA from RNA, probably due to their specificity for the conformation of the deoxycytidylate.

Animals↗