The abundance of additional N-acetyllactosamine units in N-linked tetraantennary oligosaccharides of human Tamm-Horsfall glycoprotein is a donor-specific feature

Previously, treatment of Tamm-Horsfall glycoprotein (THp) from different donors with endo-beta-galactosidase has been shown to liberate a tetra- and a Sd(a)-active pentasaccharide, concluding the presence of N-linked carbohydrate chains containing additional N - acetyllactosamine units. These type of oligosaccharides were not found in a detailed structure elucidation of the carbohydrate moiety of THp of one male donor, suggesting a donor-specific feature for these type of structures. Therefore, THp was isolated from four healthy male donors and each subjected to endo-beta-galactosidase treatment in order to release these tetra- and Sd(a)-active pentasaccharide. Differences were observed in the total amount of released tetra- and Sda-active pentasaccharide of the used donors (42, 470, 478, 718 microg/100 mg THp), indicating that the presence of repeating N-acetyllactosamine units incorporated into the N-glycan moiety of THp is donor specific. Furthermore, a higher expression of the Sd(a) determinant on antennae which display N-acetyllactosamine elongation was observed, suggesting a better accessibility for the beta-N-acetylgalactosaminyltransferase. In order to characterize the N-glycans containing repeating N- acetyllactosamine units, carbohydrate chains were enzymatically released from THp and isolated. The tetraantennary fraction, which accounts for more than 33% of the total carbohydrate moiety of THp, was used to isolate oligosaccharides containing additional N - acetyllactosamine units. Five N-linked tetraantennary oligosaccharides containing a repeating N-acetyllactosamine unit were identified, varying from structures bearing four Sd(a) determinants to structures containing no Sd(a) determinant (see below). One compound was used in order to specify the branch location of the additional N- acetyllactosamine unit, and it appeared that only the Gal-6' and Gal-8' residues were occupied by a repeating N -acetyllactosamine unit.      

Ribosomal RNA sequence phylogeny is not congruent with ascospore morphology among species in Ceratocystis sensu stricto

The genus Ceratocystis sensu stricto includes important fungal pathogens of woody and herbaceous plants. This genus is distinguished from species in Ceratocystis sensu lato by the presence of Chalara anamorphs. Ascospore shape has been used extensively in delineating Ceratocystis taxa, which show a large variety of ascospore shapes. Sequence analysis of one region of he 18S ribosomal RNA subunit and two regions of the 28S ribosomal RNA subunit showed that there was a majority of multiple substitutions at nucleotide sites and that there was a low transition/transversion ratio, T = 0.72. Both of these results suggest that these are well established, old species. Ascospore morphology, for the most part, was not congruent with the molecular phylogeny, and the use of morphological characters may be misleading in the taxonomy of these species.      

Leishmania spp.: cellular levels and synthesis of polyamines during growth cycles

Polyamines were extracted from five different leishmanial strains (Leishmania sp., L. tropica major, L. mexicana, and two L. donovani isolates) and identified as pulrescine, spermidine, and spermine by thin-layer chromatography and mass spectrometry. These sensitive methods were also used to demonstrate the conversion of radioactive putrescine into spermidine and spermine. As in other types of cells, polyamine levels fluctuated during the growth cycle, maximal levels being attained during the logarithmic growth phase. In the five leishmanial strains, which were members of four different serotypes, the spermidine—putrescine ratios also varied, and in two strains of the same serotype, polyamine ratios were practically identical, suggesting that polyamine characteristics might serve as a further criterion for strain identification and classification.     

Membrane compartmentalized ATP and its preferential use by the Na, K-ATPase of human red cell ghosts

This paper describes work which begins to define the molecular organization in the region of the membrane that comprises the functional domain of the Na:K pump. The membrane-bound phosphoglycerate kinase (PGK) and Na, K-ATPase appear to be directly linked via a compartmentalized form of ATP. Evidence for the membrane pool of ATP is based on the labeling characteristics of the phosphoproteins by [γ-(32)P]ATP of ghosts incubated under various conditions. Preincubation of ghosts in the presence of ATP at 37 degrees C, but not at 0 degrees C, completely obscures the formation of the Na-phosphoprotein in ghosts washed and subsequently incubated in the presence of [gamma-(32)P]ATP. In contrast to the Na component, the Mg component of phosphorylation is only slightly altered by preincubation with ATP. ATPase activity measured as (32)P(i) liberated during the subsequent incubation at 0 degrees C, reflects completely the differential effects of preincubation with ATP on (32)P incorporation into phosphoprotein. ATP placed within the pool by preincubation can be removed by operating the Na, K-ATPase or the PGK reaction in the reverse direction by use of exogenous substrates. Alternatively, the membrane pool of ATP can be formed also from exogenous substrates by running the PGK reaction in the forward direction. These results, while providing direct support for a membrane compartment of ATP, also indicate the location of this compartment in relation to the PGK and the Na, K-ATPase. In addition, these results also imply that the Mg and Na components are different enzymatic entities since substrate ATP can be derived from separate sources.     

Selective inhibition of precursor incorporation into ribosomal RNA in gamma-irradiated Tetrahymena pyriformis.

Sublethal doses of gamma radiation are known to inhibit total RNA synthesis in the ciliate protozoan Tetrahymena. To determine if the synthesis of a particular class of RNA is preferentially inhibited, pulse-labeled RNA was isolated from normal exponentially growing cells, irradiated cells, and cells in which total RNA synthesis had recovered to the pre-irradiation level. The RNAs were analyzed by SDS-polyacrylamide gel electrophoresis and oligo(dT)-cellulose column chromatography. Inhibition of RNA synthesis primarily involves ribosomal RNA. However, radiation does not cause a delay in the processing of precursor rRNA or a preferential loss of either of the mature rRNAs. Following irradiation, poly(A)-containing RNA [poly(A+)RNA] is synthesized at a rate up to three times greater than the control rate. The elevated poly(A+)RNA synthesis occurs during the period of depressed rRNA synthesis and even after rRNA synthesis has recovered to its pre-irradiation rate. While the sizes of the total cellular ribonucleoside triphosphate pools are depressed in the irradiated cells, these pools probably do not represent the actual compartments containing the precursors for RNA synthesis, and the observed changes cannot explain the modifications in macromolecular synthesis in irradiated Tetrahymena.     

Co-infection of Mycobacterium tuberculosis and Mycobacterium leprae in human archaeological samples: a possible explanation for the historical decline of leprosy

Both leprosy and tuberculosis were prevalent in Europe during the first millennium but thereafter leprosy declined. It is not known why this occurred, but one suggestion is that cross-immunity protected tuberculosis patients from leprosy. To investigate any relationship between the two diseases, selected archaeological samples, dating from the Roman period to the thirteenth century, were examined for both Mycobacterium leprae and Mycobacterium tuberculosis DNA, using PCR. The work was carried out and verified in geographically separate and independent laboratories. Several specimens with palaeopathological signs of leprosy were found to contain DNA from both pathogens, indicating that these diseases coexisted in the past. We suggest that the immunological changes found in multi-bacillary leprosy, in association with the socio-economic impact on those suffering from the disease, led to increased mortality from tuberculosis and therefore to the historical decline in leprosy.