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  • 1
    Publication Date: 1983-12-12
    Print ISSN: 0014-5793
    Electronic ISSN: 1873-3468
    Topics: Biology , Chemistry and Pharmacology
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  • 2
    ISSN: 1744-313X
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Medicine
    Notes: A family with examples of the rare condition known as ‘inherited mosaicism affecting the ABO blood groups’ has been studied. In this family there were five examples of Bmos:O mosaicism. Blood group gene-specified transferase estimations were studied in this condition for the first time. In ‘affected' members, levels of B gene-specified transferease were low, and amounted to only 7-10% of the activity of a normal control. It is proposed that Bmos is correctly classified as a new form of weak B.
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  • 3
    ISSN: 1744-313X
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Medicine
    Notes: The red cells of a normal male blood donor, K.S., were first grouped as B but he was found to lack anti-A in his serum. Closer investigation revealed that his red cells had very weak A activity, demonstrable only by absorption and elution of anti-A. He is a non-secretor of ABH and a secretor of Lea. Blood group A-, B and H-gene specified glycosyltransferases were detected in his serum. In contrast to the finding of a B antigen of normal strength on his red cells, the B transferase in his serum was only about 30% of the normal level and, despite the very weak A activity of K.S.'s red cells, the A transferase level was about 50% of that found in the serum of group A individuals with normal strength of A antigen. Moreover, the A transferase on the basis of its pH optimum, Km values for donor and acceptor substrates, activation by divalent cations, isoelectric focusing profile and capacity to convert O to A-active cells, was characterized as the product of an A1 gene. A family study showed that K.S.'s wife is group A2 and that they have two sons, one group A2 and the other group B. The group B son is assumed to have inherited a B gene from the propositus but the level of B transferase in the son's serum is three times as high as that in his father's serum. The wife of the propositus and his group A2 son have normal A2 transferases in keeping with their A2 red cell status. The A2 son therefore appears to have inherited an A2 gene from his mother but neither the A1 nor the B gene shown to be carried by his father. The distribution of transferase activities in K.S.'s red cells differs from that in his serum. A level of B transferase within the normal range was found in his red cell membranes but a very low level of A transferase was detected. The discrepancies between the serum transferases and ABO-red cell group, together with the pattern of inheritance within the family, led to a suspicion of chimaerism. This was confirmed by the finding of fibroblasts with the female 46XX karyotype in cultures of the propositus' skin. These results suggest that K.S. is a dispermic chimaera with two different cell lines of the genotypes BO and A1O or A1A1. The group A2 son is assumed to have inherited an O gene from his father. It seems probable that K.S.'s bone marrow and reproductive organs are comprised predominantly of the XY cell line which carries the blood group BO genotype whereas his skin and other tissues which contribute the A1 transferase to his plasma, are partly made up of the XX cell line which carries the blood group A1O or A1A1 genotype.
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  • 4
    ISSN: 1573-4986
    Keywords: β-galactosidase ; Tritrichomonas foetus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The work presented in this paper describes the purification and properties of a β-galactosidase from the protozoan Tritrichomonas foetus. An inexpensive and straightforward method for extraction of the enzyme involving ammonium sulphate precipitation, ion exchange and affinity chromatography resulted in a high level of purification. After purification β-N-acetylglucosaminidase was the only enzyme present as a contaminant at a significant level. The β-galactosidase isolated had a pH optimum of 5.8. The Km determined at pH 5.8 was found to be 2.2 mM. Interesting results were obtained when studies were carried out to determine the effect of various metal ions on enzyme activity. Of the metal ions used in this study only manganese ions were found to activate the enzyme. This seems to be a characteristic of trichomonad enzymes, as N-acetyl-β-glucosaminidase, α-galactosidase and N-acetyl-α-galactosaminidase are also activated by manganese ions. The strongest inhibition was recorded with lead and to a lesser extent by zinc. The result with lead is not unexpected as the heavy metal is known to cause irreversible inhibition by binding to the amino-acid backbone of the enzyme. The result with zinc is interesting as high levels of zinc are present and trichomonads are known to be apathogenic in semen. The purified β-galactosidase was found to have the capacity to hydrolyse lactose (Gal β1-4 Glc), lacto-N-biose 1 (Gal β1-3 GlcNAc) and N-acetyllactosamine (Gal β1-4 GlcNAc). When the enzyme was applied to a non-denaturing polyacrylamide gel a single band was observed when stained with Coomassie brilliant blue. This band coincided with that obtained when the gel was stained with p-nitrophenyl β-galactopyranoside. When the same gel was incubated with p-nitrophenyl N-acetyl β-glucopyranoside a band was detected which did not coincide with that of β-galactosidase. Since the β-N-acetylglucosaminidase enzyme does not move to the same position on a non-denaturing gel as the β-galactosidase, we will use this technique to isolate the latter enzyme and determine the N-terminal sequence as a prelude to cloning and further study of the gene.
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Glycoconjugate journal 14 (1997), S. 879-882 
    ISSN: 1573-4986
    Keywords: protozoans ; glycosidases ; mucins
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract A range of protozoans were tested for the presence of glycosidases using p-nitrophenyl sugars as substrates. Some of the organisms were mucin dwellers whereas others were blood borne parasites. It had been hypothesized that glycosidase production would be significantly higher in the mucin dwellers. The results obtained demonstrated that the urogenital protozoans Tritrichomonas foetus and Trichomonas vaginalis produced a vast range of glycosidases which included those required for mucin breakdown. The gut dwelling protozoans Giardia lamblia and Entamoeba histolytica both produced β-N-acetylglucosaminidase. G.lamblia also had detectable β N-acetylgalactosaminidase activity, and small amounts of β mannosidase were found in the extracts from E. histolytica. In contrast, little or no glycosidase activity was detected under the same experimental conditions in Leishmania donovani, Trypanosoma brucei or T. cruzi. The mucin dwelling protozoans all produce β-N-acetylglucosaminidase but only the Trichomonads produced the range of enzymes required for complete breakdown of mucin. This seems to suggest that mucin breakdown is not a characteristic of all mucin dwelling protozoans.
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Glycoconjugate journal 14 (1997), S. 159-173 
    ISSN: 1573-4986
    Keywords: blood group antigens ; glycoproteins ; carbohydrates
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The blood group antigens have been dismissed by some researchers as merely 'icing on the cake' of glycoprotein structures. The fact that there are no lethal mutations and individuals have been described lacking ABO, H and Lewis antigens seems to lend weight to the argument. This paper reviews the research which suggests that these antigens do indeed have function and argues that blood group antigens play important roles in modulation of protein activity, infection and cancer. It explores the evidence and poses questions as to the relevance and implications of the results.
    Type of Medium: Electronic Resource
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