Biomedical subjects
Publications and source records attributed to G Erhardt.
In German Simmental cattle a new kappa-casein variant was detected by isoelectric focusing, which cannot be distinguished from kappa-casein A by polyacrylamide and starch gel electrophoresis. It was named kappa-casein D. The frequencies of kappa-casein alleles were kappa-Cn A 0.75, kappa-Cn B 0.24, kappa-Cn D 0.01.
Isoelectric focusing with carrier ampholytes in ultrathin polyacrylamide gels and polyacrylamide gel electrophoresis in a discontinuous buffer system were used for the separation of sheep transferrin variants. For identification of the different iron-binding sites of transferrin a stepwise urea gradient, different degrees of iron saturation and double one-dimensional electrophoresis were used. Isoelectric focusing results in an increased resolution of the Fe0-transferrin, Fe1-transferrin and Fe2-transferrin region. At the level of Fe0-transferrin and Fe1-transferrin the variants I, A, G, B, C, D, M, E, Q, P can be identified. The method is especially suitable for genetic studies. For screening purposes up to 108 samples can be separated within one run in an ultrathin gel.
A method is described which allows the simultaneous separation of all polymorphic protein fractions in cow's milk in one single run. The separation could be achieved by isoelectric focusing in ultrathin-layer polyacrylamide gels. The method is especially suitable for screening purposes because it combines low costs, high resolution and short separation time.
Because of conflicting reports on plasma levels of total immunoreactive glucagon (IRG) in obesity, we investigated, by gel filtration, the individual IRG fractions in grossly obese patients (N = 16; BMI 40 +/- 2) as compared with normal weight subjects (N = 18). Mean total IRG was 142 +/- 12 pg/ml in normal subjects and 190 +/- 15 pg/ml (P less than 0.02) in obese subjects. IRG3500 was 16 +/- 2 pg/ml in normal subjects and 34 +/- 5 pg/ml (P less than 0.005) in the obese subjects. Obese patients with normal glucose tolerance demonstrated 30 +/- 5 pg/ml IRG3500 (N = 11; P less than 0.01) as compared with those who were obese with impaired glucose tolerance (42 +/- 12 pg/ml, N = 5; P less than 0.0025), although the total IRG of the latter group (173 +/- 31 pg/ml) was not different from that of normal subjects. IRG90000 was of comparable magnitude in the entire groups of obese and normal subjects. A wide variability of big plasma glucagon levels was found in all three groups, mean levels not being significantly different. These data suggest that plasma IRG3500 levels are elevated in grossly obese patients, particularly in those patients with impaired glucose tolerance, a finding that may be masked by mere measurements of total plasma IRG.
Levels of lactoferrin, an Fe-binding protein with bacteriostatic properties, were determined in the colostrum and milk of Yorkshire sows during a 21-d lactation. Lactoferrin levels averaged 1,100 to 1,300 micrograms/ml near the time of farrowing, then declined sharply during the first week of lactation. Concentration of lactoferrin showed considerable variation among sows, but not among teat positions (anterior to posterior). A method for isolating high purity swine lactoferrin is described.
Explore the source record for details and available documents.
Ten Holstein-Friesian cows were distributed according to their lactoferrin and lysozyme concentrations in milk into groups with high and low concentrations. In each cow, a front and a rear mammary quarter was infected by inoculation of 10(8) colony forming units of Staphylococcus aureus while the other two quarters were infused with 2 ml of sterile milk. The reaction was observed during the following nine days. After 10 hours the cell count, the lactoferrin and lysozyme concentrations were increased in the infected and control quarters. In milk samples with a high initial lactoferrin concentration the colony forming units of S. aureus were higher than in those with a low concentration. In milk samples with a high lysozyme concentration with colony forming units of S. Aureus were significantly lower than in those with low concentrations. These results show, that the lysozyme concentration in milk of healthy udders could indicate the preparedness for defense against infectious diseases.
Explore the source record for details and available documents.
A rapid method for determination of the primary structures for beta-lactoglobulin (beta-LG) genetic variants is described. This included rapid microbore HPLC, amino acid analyses, and wherever necessary, direct peptide sequencing. Two novel variants of beta-LG have been identified, bovine beta-LG W and ovine beta-LG C. The proteins were oxidized, digested with trypsin and separated using RP-HPLC. All peptides were recovered in a single run. Peptides with amino acid exchanges were identified by retention time and subjected to amino acid and sequence analyses. Ovine beta-LG C differs from the ovine beta-LG A variant by a single amino acid exchange at position 148 where Arg is replaced by Gln. Bovine beta-LG W differs from bovine beta-LG B by having Leu at position 56 instead of Ile. The method described here is reliable and can be used for mapping of 20-1000 pmol of material.
The proportion of unpigmented coat on the trunk was determined from photographs of 38 German Simmental and 627 German Holstein bulls distributed over three generations. All 665 animals were members of 18 Holstein and 3 Simmental half-sib families. A Bayesian estimation of heritability yielded a posterior mean of 0.88 and a standard error of 0.08. A quantitative trait loci (QTL) scan over all chromosomes covered by 229 microsatellite marker loci (2926 cM) was performed by fitting a multiple marker regression model to 625 observations from the youngest generation in 18 families. On chromosome 6 a QTL for the proportion of white coat with large effects (experiment-wise error probability < .0001) was found and a less important one on chromosome 3 (chromosome-wise error probability < .009). Chromosome 6 is known to harbor the KIT locus (receptor tyrosinase kinase), which is associated with various depigmentation phenotypes in mice, humans, and pigs. Similarity of phenotypic KIT effects in other species and synteny with the reported QTL suggest that KIT is a serious candidate gene for the degree of spotting in cattle. The results are also discussed with respect to resistance to solar radiation, heat stress, and photosensitization.
Genome scans for quantitative trait loci (QTL) in farm animals have concentrated on primary production and health traits, and information on QTL for other important traits is rare. We performed a whole genome scan in a granddaughter design to detect QTL affecting body conformation and behavior in dairy cattle. The analysis included 16 paternal half-sib families of the Holstein breed with 872 sons and 264 genetic markers. The markers were distributed across all 29 autosomes and the pseudoautosomal region of the sex chromosomes with average intervals of 13.9 cM and covering an estimated 3155.5 cM. All families were analyzed jointly for 22 traits using multimarker regression and significance thresholds determined empirically by permutation. QTL that exceeded the experiment-wise significance threshold (5% level) were detected on chromosome 6 for foot angle, teat placement, and udder depth, and on chromosome 29 for temperament. QTL approaching experiment-wise significance (10% level) were located on chromosome 6 for general quality of feet and legs and general quality of udder, on chromosome 13 for teat length, on chromosome 23 for general quality of feet and legs, and on chromosome 29 for milking speed. An additional 51 QTL significant at the 5% chromosome-wise level were distributed over 21 chromosomes. This study provides the first evidence for QTL involved in behavior of dairy cattle and identifies QTL for udder conformation on chromosome 6 that could form the basis of recently reported QTL for clinical mastitis.