In situ localization and characterization of different classes of chromosomal DNA: acridine orange and quinacrine mustard fluorescence

In situ denaturation of metaphase chromosomes with alkali results in a shift from green to yellow, orange, brown and red fluorescence with acridine orange, indicating increasing denaturation of chromosomal DNA. The kinetics and characteristics of denaturation are described. Mouse and Microtus agrestis chromosomes denature uniformly but human cells show sequential denaturation. With increasing concentrations of alkali, the secondary constrictions in chromosomes 1, 9 and 16 are the first, and the distal half of the Y chromosome the last, to become denatured. — Reassociation of chromosomal DNA occurs within seconds after the start of incubation in salt solution. Areas containing repetitious DNA, e.g. mouse centromeres, fluoresce much more strongly than other regions with acridine orange after prolonged reassociation. Since human and Microtus centromeric regions behave similarly, it is proposed that they, too, contain repetitious DNA. — Reassociation treatment leads to enhancement of bright quinacrine mustard fluorescence in regions already bright before treatment. Furthermore, regions containing repetitious DNA, e.g. the secondary constrictions in human chromosomes 1, 9 and 16, whose fluorescence is dull before treatment, turn bright after reassociation. — The methods of fluorescence analysis of mammalian chromosomes with acridine orange and quinacrine mustard permit the localization and study of different classes of chromosomal DNA.     

Bi-antennary oligo-(N-acetyllactosamino)glycans of I-type are galactosylated preferentially at the GlcNAcβ1-6Gal linked arms by α1,3-galactosyltransferase of bovine thymus

1,3-Galactosylation of radiolabelled bi-antennary acceptors Gal1-4GlcNAc1-3(Gal1-4GlcNAc1-6)Gal-R (R=1-OH, 1-4GlcNAc or 1-4Glc) with bovine thymus 1,3-galactosyltransferase was studied. At all stages of the reactions the three acceptors reacted faster at the 1 6 linked arm than at the 1 3 linked branch. Hence, in addition to the doubly 1,3-galactosylated products, practically pure Gal1-4GlcNAc1-3(Gal1-3Gal1-4GlcNAc1-6)Gal-R could be obtained from the three acceptors in reactions that had proceeded to near completion. The isomeric mono-1,3-galactosylated products were identified by using exoglycosidases to remove the branches unprotected by 1,3-galactoses and by subsequently identifying the resulting linear glycans chromatographically.Abbreviations Gal d-galactose - GlcNAc N-acetyl-d-glucosamine - Lac lactose - LacNAc Gal1-4GlcNAc - MH maltoheptaose - MP maltopentaose - MT maltotriose - MTet maltotetraose - WGA wheat germ agglutinin - 3 position 3 of the galactose unit of LacNAc or Lac - 6 position 6 of the galactose unit of LacNAc or Lac     

The relation between solution association and surface activity of the hydrophobin HFBI from Trichoderma reesei

Hydrophobins are small fungal surface active proteins that self-assemble at interfaces into films with nanoscale structures. The hydrophobin HFBI from Trichoderma reesei has been shown to associate in solution into tetramers but the role of this association on the function of HFBI has remained unclear. We produced two HFBI variants that showed a significant shift in solution association equilibrium towards the tetramer state. However, this enhanced solution association did not alter the surface properties of the variant HFBIs. The results show that there is not a strong relationship between HFBI solution association state and surface properties such as surface activity.     

A Genomewide Screen for Schizophrenia Genes in an Isolated Finnish Subpopulation, Suggesting Multiple Susceptibility Loci

Schizophrenia is a severe mental disorder affecting approximately 1% of the world's population. Here, we report the results from a three-stage genomewide screen performed in a study sample from an internal isolate of Finland. An effort was made to identify genes predisposing for schizophrenia that are potentially enriched in this isolate, which has an exceptionally high lifetime risk for this trait. Ancestors of the local families with schizophrenia were traced back to the foundation of the population in the 17th century. This genealogical information was used as the basis for the study strategy, which involved screening for alleles shared among affected individuals originating from common ancestors. We found four chromosomal regions with markers revealing pairwise LOD scores>1.0: 1q32.2-q41 (Z(max)=3.82, dominant affecteds-only model), 4q31 (Z(max)=2. 74, dominant 90%-penetrance model), 9q21 (Z(max)=1.95, dominant 90%-penetrance model), and Xp11.4-p11.3 (Z(max)=2.01, recessive 90%-penetrance model). This finding suggests that there are several putative loci predisposing to schizophrenia, even in this isolate.     

Cytosolic and nuclear aggregation of the amyloid beta-peptide following its expression in the endoplasmic reticulum

Misfolded secretory and membrane proteins are known to be exported from the endoplasmic reticulum (ER) to the cytosol where they are degraded by proteasomes. When the amount of exported misfolded proteins exceeds the capacity of this degradation mechanism the proteins accumulate in the form of pericentriolar aggregates called aggresomes. Here, we show that the amyloid beta-peptide (Abeta) forms cytosolic aggregates after its export from the ER. These aggregates share several constituents with aggresomes. However, Abeta aggregates are distinct from aggresomes in that they do not accumulate around the centrosome but are distributed randomly around the nucleus. In addition to these cytosolic aggregates, Abeta forms intranuclear aggregates which have as yet not been found for proteins exported from the ER. These findings show that proteins exported from the ER to the cytosol which escape degradation by the proteasome are not necessarily incorporated into aggresomes. We conclude that several distinct aggregation pathways may exist for proteins exported from the ER to the cytosol.     

Binding characteristics of Escherichia coli type 1 fimbriae in the human kidney

Binding of the Escherichia coli type 1 fimbriae to frozen sections of human kidney was examined by indirect immunofluorescence. The purified fimbriae bound specifically to the luminal and cytoplasmic aspects of proximal tubules and to the connective tissue layer of veins and arteries. Distal tubules, collecting ducts, glomeruli and vascular endothelium were not stained by the fimbriae. The results do not support a role for type 1 fimbriae in invasion of E. coli into the renal parenchyma.     

The elemental composition, the microfibril angle distribution and the shape of the cell cross-section in Norway spruce xylem

Relationships between the elemental composition, the microfibril angle (MFA) distribution and the average shape of the cell cross-section of irrigated-fertilised and untreated Norway spruce (Picea abies [L.] Karst.) earlywood were studied. Sample material was obtained from Flakaliden, Sweden. The elemental composition was studied by determining the relative mass fractions of the elements P, S, Cl, K, Ca and Mn by X-ray fluorescence and by determining the mass absorption coefficients for X-rays. X-ray diffraction was used to determine the MFA distribution and the average shape of the cell cross-section. The latter was also determined by light microscopy. In transition from juvenile wood to mature wood, a decrease of the mode of the MFA distribution from 13°–24° to 3°–6° was connected to a change in the shape of the cell cross-section from circular to rectangular. The irrigation-fertilisation treatment caused no change in the MFA distribution or in the shape of the cell cross-section, whereas the mass absorption coefficient was higher and the density was smaller in irrigated-fertilised wood. Larger proportion of the elements S, Cl and K, but smaller proportion of the element Mn, were observed due to the treatment. The results indicate that the shape of the cell cross-section or the MFA distribution are not directly linked to the growth rate of tracheids or to the nutrient-element content in the xylem and only show notable changes as a function of the cambial age.     

Towards all-european pollen reports

In the first European Pollenflight Symposium in Königswinter, BRD, March 20–21, in 1987 the outlines for an European data bank were published. By that time Vienna, Austria was already in state of readiness. Since that, countries in Europe have an opportunity to send their prevailing pollen data to the data bank in Vienna, where a software server is ready to accept new data and to send reports day and night. The software of the data bank has been customed to facilitate calculations on PC level. The developing data bank gives a possibility e.g., (1) to compare pollen seasons in various parts of Europe, (2) to make pollen forecasts in different parts of Europe more accurately, (3) to find pollenfree sites in Europe for allergic people, (4) to find out long-time changings in regional and overregional flora as well as in the allergen-content of the air and (5) even to make all-European pollen reports. These could be broadcasted by common satellite TV channels and seen in most European countries. The aim of this study was to compare pollen seasons of the most common allergic symptoms causing plants in Europe: Alnus, Corylus, Betula, Poaceae and Artemisia in 1988 and 1989 and their distribution in Europe. Olea and Parietaria, being widespread pollen allergens in the Mediterranean, have not been taken into consideration for this study in terms of missing data from Spain, southern France and Greece. Information on flowering has been received from Austria, Belgium, BRD, DDR, Denmark, Finland, Italy, The Netherlands, Norway, Poland, Sweden, Switzerland, United Kingdom and the newest site in Estonian SSR. As the number of participating countries is still increasing, (Hungary and France are preparing for joining in 1990), there is no doubt that the need and benefit of a common pollen data bank has been realized in whole Europe.     

Internal structure of chlorosomes from brown-colored chlorobium species and the role of carotenoids in their assembly

Chlorosomes are the main light harvesting complexes of green photosynthetic bacteria. Recently, a lamellar model was proposed for the arrangement of pigment aggregates in Chlorobium tepidum chlorosomes, which contain bacteriochlorophyll (BChl) c as the main pigment. Here we demonstrate that the lamellar organization is also found in chlorosomes from two brown-colored species (Chl. phaeovibrioides and Chl. phaeobacteroides) containing BChl e as the main pigment. This suggests that the lamellar model is universal among green sulfur bacteria. In contrast to green-colored Chl. tepidum, chlorosomes from the brown-colored species often contain domains of lamellar aggregates that may help them to survive in extremely low light conditions. We suggest that carotenoids are localized between the lamellar planes and drive lamellar assembly by augmenting hydrophobic interactions. A model for chlorosome assembly, which accounts for the role of carotenoids and secondary BChl homologs, is presented.