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Biomedical subjects

R Krishnamoorthy

Publications and source records attributed to R Krishnamoorthy.

At least 181 records · Page 10Linked to original sources
PubMed1977

Hemoglobin Djelfa beta98 (FG 5) Val leads to Ala: isolation and functional properties of the heme saturated form.

Hemoglobin Djelfa beta98 (FG 5) Val leads to Ala is a neutrally substituted unstable hemoglobin, exhibiting the same gross features as hemoglobin Köln beta98 (FG 5) Val leads to Met. In addition to the presence of a deheminized fraction, a heme saturated abnormal hemoglobin was visualized and isolated by high resolution electrofocusing. By functional studies of the fully heminized form, a slightly increased oxygen affinity, an impairment of heme-heme interaction and a decreased response to organic phosphates were demonstrated. These functional perturbations point out the importance of the beta98 invariant valyl residue, in the quaternary contacts. They can account for the poor oxygen delivery of erythrocytes.

Alanine↗
PubMed1977

[A new case of hemoglobin J Capetown alpha 92 (FG 4) Arg replaced by gln].

Hemoglobin J Capetown was found incidentally in a patient of french origin suffering from urticaria with delayed pressure oedema. Using a preparative finger-print technique, the structural determination was easy. A functional study of the purified component confirmed the high oxygen affinity of hemoglobin J Capetown and demonstrated a low reactivity for organic phosphates. These results may explain the perturbations observed in the whole blood.

Amino Acids↗
PubMed1976

Isoelectrofocusing: a method of multiple applications for hemoglobin studies.

A microanalytical screening of hemoglobins by isoelectric focusing on acryl-amide gel columns is described. Addition of this technique to our regular analytical procedures revealed many mutants, praticularly some neutral ones which were not resolved by other conventional procedures. Extension of this technique to a quantitative scale permitted rapid isolation of some unstable mutants in an almost pure form ready for functional studies. The natural color of the separated components is often indicative of their nature and in cases like the sulfhemoglobin, Hbs M, they are of diagnostic value. The heme-losing, abnormal, unstable mutants, on the addition of external cyanhemin, take them up and change their isoelectric pH. This is an attractive visible procedure for their diagnosis. From all these results, it appears that isoelectric focusing as a single method brings more information than the other conventional procedures and hence can be considered as a semi-routine investigation for hemoglobin studies before deciding on a much longer procedure.

Fetal Hemoglobin↗
PubMed1976

Congenital enzymopenic methaemoglobinaemia. Clinical and biochemical study of a family with three homozygotes.

Three brothers with congenital recessive methaemoglobinaemia without mental retardation were found to be homozygous for NADH diaphorase deficiency. Twelve family members were heterozygous. One of the probands had marked digital clubbing, an unusual feature in this disease. In the probands, the red-cell NADH diaphorase was very low and unstable, whereas in the leucocytes this enzyme was present at a normal level. Isoelectric focusing of haemoglobin in the three probands showed that the alpha-chain was preferentially oxidized spontaneously. This confirms the greater oxidizability of this chain, as already described on isolated chains.

Adolescent↗
PubMed1976

A case of hemoglobin M Boston. New data about valency hybrids brought by isoelectrofocusing study.

In Hemoglobins M, as the result of a mutation theheme iron of the abnormal chain is atabilized in an oxidized form unable to carry oxygen. In this paper, we discuss the case of hemoglobin M Boston characterizing this abnormal hemoglobin as valency hybrid by spectral studies and utilising this mutant as a marker, in isoelectricfocusing, we bring the arguments that the two intermediary bands of oxidation correspond to alpha2+beta2+2 and alpha2+2beta2+3 We also indicate that the abnormal spectrum of Hb M interferes with the estimation of methemoglobin, giving erroneous values. We have shown that isoelectric focusing and subsequent scanning give a definite idea about the amount of abnormal chain present.

Densitometry↗
PubMedDate not supplied

An evaluation of allozyme amino acid substitutions for the study of molecular relationships in Providencia strains.

Through analysis of molecular relationships in terms of amino acid substitutions, intra- and interspecies differentiations in Providencia alcalifaciens, P. stuartii and P. rustigianii were evaluated among the electrophoretic variants of three enzymes, L-malate dehydrogenase, acid phosphatase and esterase-beta a, chosen for their distinct pattern of polymorphism. For each enzyme, molecular relatedness among variants defined by two-dimensional electrophoretic profiles was examined through protein titration curves. P. stuartii strains appeared identical to each other and P. rustigianii strains were closely related, whereas the division of P. alcalifaciens strains into previously described zymotypes A1 and A2 was refined in molecular terms. A gradient of molecular interrelatedness between the species was observed for the three enzyme loci: with L-malate dehydrogenase, the three species appeared very closely related; with acid phosphatase, P. stuartii and P. alcalifaciens were more closely related to each other than to P. rustigianii; with esterase-beta a, P. alcalifaciens and P. stuartii appeared partially related, whereas no such relatedness was observed between these two species and P. rustigianii.

Acid Phosphatase↗
PubMedDate not supplied

Correlation between DNA polymorphism and enzyme polymorphism argues in favour of the delineation of two species within Providencia alcalifaciens.

Ribosomal DNA (rDNA) polymorphism was compared to enzyme polymorphism and DNA/DNA hybridization data for the intraspecies differentiation of Providencia alcalifaciens. DNA from 27 strains previously classified into two zymotypes A1 and A2 and discriminated by two levels of DNA/DNA hybridization (delta Tm values of 0 to 1 degree C and 6 to 10 degrees C, respectively) were analysed by Southern blotting for rDNA polymorphism. The ribotypes fell into two ribogroups A1 and A2, which correlated with the corresponding zymotypes. This correlation argues for the proposed creation of two species within P. alcalifaciens.

Blotting, Southern↗
PubMedDate not supplied

Characterization of Escherichia hermannii by ribosomal DNA restriction fragment length polymorphism.

Ribosomal DNA polymorphism was used to characterize strains of Escherichia hermannii and to differentiate them from E. coli. DNA from 11 E. hermannii strains previously separated into three zymotypes by enzyme electrophoretic polymorphism was digested with HindIII and EcoRI restriction enzymes and analyzed by Southern blotting. The 10 ribotypes obtained with EcoRI fell into 3 groups which correlated with the corresponding zymotypes, and the 5 ribotypes obtained with HindIII were clearly distinct from those of E. coli strains.

Blotting, Southern↗