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G Erhardt

Publications and source records attributed to G Erhardt.

At least 73 records · Page 4Linked to original sources
PubMed1996

Isolation and rapid sequence characterization of two novel bovine beta-lactoglobulins I and J.

Two novel bovine beta-lactoglobulins I and J have been isolated from bovine milk and characterized by isoelectric focusing. Their primary structure was determined by a very rapid method consisting of a combination of Edman sequencing, mass analysis, and ladder sequencing by mass spectrometry. We found that both new beta-lactoglobulins are of the bovine beta-lactoglobulin B-variant type. beta-lactoglobulin I shows Gly instead of Glu at position 108, whereas beta-lactoglobulin J shows a Pro-to-Leu exchange at position 126.

Amino Acid Sequence↗
PubMed1996

Detection of a new kappa-casein variant in milk of Pinzgauer cattle.

A new kappa-casein variant (kappa-CN G) with a frequency of 0.003 was demonstrated in Pinzgauer cattle from Austria and Bavaria, Germany by isoelectric focusing in polyacrylamide gels and by alkaline polyacrylamide gel electrophoresis. Kappa-CN G was not present in milk samples of Limpurger, another endangered breed.

Animals↗
PubMed1996

Allele frequencies of the major milk proteins in the Finnish Ayrshire and detection of a new kappa-casein variant.

A total of 20990 Finnish Ayrshire cows were phenotyped for the major milk proteins by isoelectric focusing in polyacrylamide gels. The predominant alleles in the Finnish Ayrshire were alpha S1-casein B (0.999), alpha S2-casein A (0.991), beta-casein A1 (0.509) and alpha 2 (0.490), kappa-casein A (0.612) and beta-lactoglobulin B (0.716). The kappa-casein E allele (0.307) was also rather common in the Finnish Ayrshire. A new kappa-casein variant (kappa-casein F) was demonstrated in two Finnish Ayrshire cows, a dam and a daughter.

Alleles↗
PubMed1996

Molecular genetic characterization of new bovine kappa-casein alleles CSN3F and CSN3G and genotyping by PCR-RFLP.

In order to characterize the two new kappa-casein variants F and G (CSN3F and CSN3G) recently detected in Ayrshire and Pinzgauer cattle, exon IV of CSN3 from heterozygous animals was amplified by polymerase chain reaction (PCR), cloned and sequenced. The sequencing data revealed single point mutations at nucleotide positions 10530 (G-->A) for CSN3F and 10790 (C-->T) for CSN3G, corresponding to amino acid exchanges in positions 10 (Arg-->His) and 97 (Arg-->Cys) respectively. These mutations alter recognition sites for the restriction enzymes HhaI and MaeII, which were subsequently used to confirm these polymorphisms in cattle carrying CSN3F or CSN3G. A PCR-restriction fragment length polymorphism (RFLP) genotyping procedure for all currently known CSN3 alleles (CSN3A, CSN3B, CSN3C, CSN3E, CSN3F, CSN3G) was developed.

Alleles↗
PubMed1994

A single point mutation results in A allele-specific exon skipping in the bovine alpha s1-casein mRNA.

Bovine alpha s1-casein (alpha s1-CN) allele A is found in low allelic frequencies among different cattle breeds and is known to be characterized by the deletion of amino-acid residues 14 to 26 of the mature protein (as defined via the most common allele B), and a corresponding deletion of 39 bp from its cDNA. Based upon the genomic sequence of bovine alpha s1-CN [Koczan et al., Nucleic Acids Res. 19 (1991) 5591-5596], this allelic deviation can be interpreted as an absence of exon 4 from the A allele mRNA and protein product. We demonstrate that this allelic aberration is not caused by a genomic deletion across the exon-4 DNA, but is correlated with a single point mutation at position +6 in the splice donor sequence distal of exon 4, which results in upstream exon skipping during the serial splice reactions of the A allele alpha s1-CN pre-mRNA. The A-allele-specific mutation at position +6 is able to interrupt the perfect complementarity of the intron-4 splice donor signal (positions one to eight) with U1-snRNA, which may then no longer be able to compensate for a rather weak exon-4 upstream splice acceptor sequence in facilitating the initial binding of U2 auxiliary factor/65-kDa (U2AF65) to that polypyrimidine tract. This interpretation of the exon skipping mechanism in alpha s1-CN allele A is in agreement with similar results obtained [Hoffmann and Grabowski, Genes Dev. 6 (1992) 2554-2568] in an analysis of the rat preprotachykinin-encoding gene and in vitro experiments.

Alleles↗
PubMed1993

Linkage between the loci for serum albumin and vitamin D binding protein (GC) in sheep.

Evidence for close genetic linkage between the loci for serum albumin (ALB) and vitamin D binding protein (GC) in sheep is presented. No recombinants were found in 28 informative offspring of a single ram family. The recombination frequency between the two loci was estimated to be in the range of 0 to 10%. No sign of linkage was observed between the ALB-GC complex and transferrin.

Animals↗
PubMed1993

Biochemical characterization of the bovine genetic kappa-casein C and E variants.

Analysis of elution profiles of enzymatic and CNBr digests of kappa-caseins C and E, and sequencing of most relevant peptides allowed the chemical characterization of both genetic variants. They differ from their B and A allelic counterparts by a single substitution, His97/Arg and Gly155/Ser, respectively. Electrophoretic behaviour of the investigated C and E variants was in good agreement with the observed amino acid replacements.

Alleles↗
PubMed1993

A new alpha S1-casein allele in bovine milk and its occurrence in different breeds.

A new alpha S1-casein variant (alpha S1-CN F) with a frequency of 0.009 was demonstrated in a genetic resource of German Black and White Cattle by isoelectric focusing in polyacrylamide gels and by polyacrylamide gel electrophoresis under alkaline conditions. alpha S1-CN F was not present either in German Holstein Friesians, which originate from crossing Holstein Friesians with German Black and White Cattle, or in milk samples from eight other breeds in Germany.

Alleles↗
PubMed1991

Genotyping of bovine kappa-casein (kappa-CNA, kappa-CNB, kappa-CNC, kappa-CNE) following DNA sequence amplification and direct sequencing of kappa-CNE PCR product.

Genomic DNA isolated from blood and semen of dairy cattle with known kappa-casein (kappa-CN) genotypes was subjected to Southern blot hybridization and polymerase chain reaction (PCR) using up to 14 restriction endonucleases. kappa-casein genotypes AA, AB and BB were identified using Hin dIII and Hin fI while genotypes with kappa-CNC and kappa-CNE were misidentified. Direct sequencing of the PCR product (kappa-CN EE) showed a substitution of guanine (kappa-CNA,B) by adenine (kappa-CNE) which creates a HaeIII restriction site. Therefore using PCR followed by Hin dIII or HinfI and Hae III digest allows discrimination between kappa-casein A, B and E directly at the DNA level.

Animals↗
PubMed1990

[Effect of parenteral iron doses on the measurement of red blood parameters and on weight development in lambs of different breeds].

Conventionally reared male and female lambs of Merinoland- (n = 87) and Rhön sheep (n = 30) were injected at day 3 of age with 300 mg iron dextran. Body weight of the animals was determined and blood samples were taken at day 3, 10, 21 and 42 of age. Glutathione (GSH) and haemoglobin (Hb) concentrations in blood, haematocrit (PCV), mean corpuscular haemoglobin concentration (MCHC) as well as haemoglobin-type (Hb-type) and the occurrence of foetal and anaemic Hb-bands after electrophoretic separation were determined. Data were analysed by least squares procedures where the effects of breed, sex, number of lambs born, Hb-type, foetal and anaemic Hb-bands were considered as fixed factors. Independent of all fixed factors, the application of iron dextran increased daily gain from day 3 to 10 of age in all lambs treated. Mainly twins and male lambs showed higher daily gains in this period when compared with the control groups. In untreated lambs lower values for blood parameters were observed within the first week of life, but no negative influence was found in daily gain until day 42. Between Merinoland- and Rhön sheep, significant differences in GSH concentration of blood where found which were not influenced by the application of iron. Lambs with a detectable foetal band at day 42 of age showed significant lower daily gains, MCHC, and Hb-concentrations when compared with lambs lacking this band. Interactions between occurrence of anaemic band and erythrocyte measurements could not be shown.

Animals↗
PubMed1989

Evidence for a third allele at the beta-lactoglobulin (beta-Lg) locus of sheep milk and its occurrence in different breeds.

Milk samples from 189 Merinoland Sheep, 145 Black Faced Mutton Sheep, 89 East Friesian Milk Sheep, 36 Rhön, 36 Pleven, 23 Tsigaja, 25 Black Razka and 86 Hungarian Merino X Pleven (F1) sheep were analysed by polyacrylamide gel electrophoresis under acid conditions and isoelectric focusing in ultrathin layer polyacrylamide gels with carrier ampholytes. Six different beta-lactoglobulin (beta-Lg) phenotypes (A, AB, B, AC, BC and C) were observed by both methods. The occurrence of three codominant alleles (beta-LgA, beta-LgB, beta-LgC) at an autosomal locus (beta-Lg) was supported by family and population data on genetic equilibrium. Differences in gene frequencies between the breeds were observed.

Alleles↗
PubMed1989

Isolation and complete primary sequence of a new ovine wild-type beta-lactoglobulin C.

A new wild type of beta-lactoglobulin has been identified in the milk of sheep. It has been designated as ovine beta-lactoglobulin C. Its primary structure has been determined by direct protein microsequencing of intact protein and RP-HPLC-derived tryptic peptides. The new beta-lactoglobulin C is a subtype of ovine beta-lactoglobulin A with a single exchange Arg-Gln at position 148. This exchange may influence polymerisation of beta-lactoglobulin since in the crystal structure of orthorhombic bovine beta-lactoglobulin, residues 145-150 constitute a short beta-sheet region involved in dimer formation by pairing of dyad-related strands.

Amino Acid Sequence↗