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B Senft

Publications and source records attributed to B Senft.

At least 19 recordsLinked to original sources
PubMed1996

Structural deviations in a bovine low expression lysozyme-encoding gene active in tissues other than stomach.

Lysozyme-encoding genes (Lys) constitute a gene-family in ruminants. While several of these genes are highly expressed in stomach (sLys), few other copies are weakly expressed in other tissues, notably in polymorphnuclear granulocytes and macrophages (mLys). Searching an understanding for these grossly different levels of expression, we isolated the bovine variant of the gene being expressed in granulocytes and characterized it by sequencing, together with its promoter. Spanning about 9 kb of genomic DNA, the gene is found to be segmented into four exons, in common with all other Lys, as known from vertebrates. Sequence homologies between all bovine sLys-variants exceeds 70% over much of the entire coding sequence and promoter region. This indicates (i) that bovine lysozymes expressed either in stomach or granulocyte originate from a common ancestral gene and (ii) also excludes the possibility that the observed weak expression of the mLys gene is due to major structural rearrangements within the promoter segment. However, primer extension analysis based on RNA isolated from kidney locates the transcription startpoint (tsp of that gene) 44 nt further upstream than observed in both, bovine stomach lysozyme RNA or any of the homologous genes in mice and man. The observed weak expression of this bovine mLys gene appears to be a consequence of both the presence of an extra ATG codon in the extended 5'-UTR, and a severe down mutation of the ancestral TATA-box which is only partially compensated for by the presence of another mutation further upstream resulting in a weak substitute promoter sequence.

Animals↗
PubMed1994

Lysozyme-encoding bovine cDNAs from neutrophile granulocytes and mammary gland are derived from a different gene than stomach lysozymes.

cDNA copies of a bovine lysozyme (bLys)-encoding gene (Lys) were isolated from libraries specific for granulocytes, as well as the lactating mammary gland. Analysis of each of the longest Lys-specific cDNA inserts revealed nucleotide sequence identity over the entire overlap of 1418 bp. Incomplete at the 5' end, the combined sequence codes for 11 of the 18-amino-acid (aa) Lys leader peptide and 130 aa residues of the mature Lys. Similar to mouse and human Lys from blood cells, the encoded protein contains one aa residue more (Pro103) than any of the bLys derived from stomach. Furthermore, unlike any of the known bLys genes, our sequence reveals the copy of a bovine retroposon element in the 3' untranslated region (UTR) of the mRNA approximately at the same position where an Alu-retroposon element resides within the human copy of the gene. As a further distinction from bLys expressed in stomach, we identified a segment within the 3'UTR of the mRNA which is conserved between the bovine and human blood cell variants of the Lys, but does not have significant sequence homology to any of the bovine lysozyme genes known so far. By sequence comparisons, we present evidence that this segment has been deleted during evolutionary divergence of the stomach Lys. Hence, we describe the sequence of a heretofore unknown bLys, being expressed in granulocytes. Bearings of our observations on the understanding of Lys evolution are discussed, as well as the possibility that the product of this gene may be responsible for the functional Lys activity in bovine milk.

Amino Acid Sequence↗
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↗
PubMed1991

[Defense mechanisms of the bovine mammary gland].

In the mammary gland of cattle there is a complex defense system of non-specific and specific reactions available preventing the invasion of pathogenic bacteria. Most infections occur via the teat canal, so teat canal keratin (SKK) is of particular importance in non-specific defense of the gland. The SKK serves as a physical barrier, and bacteriostatic and/or bactericidal effects of SKK lipids and proteins against certain mastitis bacteria could be demonstrated. By increasing the concentrations of lactoferrin and lysozyme in milk a reduction of mastitis frequencies could be observed. However, those high concentrations in the proteins occur only during the dry period of the cow. An improvement of the mastitis situation would also appear possible by increasing phagocytosis. The numerous trials intended to reduce mastitis by improving specific protection showed no significant success. Therefore, the most successful and cheapest means to achieve udder health remains the strict and consistent hygiene of housing, animals and mammary glands.

Animals↗
PubMed1987

Detection of a new kappa-casein variant in cow's milk.

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.

Alleles↗
PubMed1984

Isolation of lactoferrin and its concentration in sows' colostrum and milk during a 21-day lactation.

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.

Animals↗
PubMed1981

Growth inhibition of Staphylococcus aureus after experimental infection of the udder by high and low concentration of lactoferrin and lysozyme in milk.

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.

Animals↗