Ultrastructure of Nitrosospira sp. X101 with crystalline outer membrane protein (COMP)

Abstract The outer membrane (OM) structure of Nitrosospira sp. X101 was studied by different electron microscopic techniques and SDS-PAGE. A crystalline outer membrane protein was visible in freeze-etched cells, occasionally seen also in the thin sectioned cells, but was difficult to see in a negatively-stained preparation. The lattice probably consists of large globular protein subunits with a hexagonal arrangement. The molecular weights of the major proteins in the cell envelope are 35 kDa, 40 kDa and 42 kDa.     

Mineralization of carbon and nitrogen in soil samples taken from three fertilized pine stands: Long-term effects

Seven years after fertilization the rate of CO₂ production in the soil samples taken from the organic horizons of a poor pine forest site (Calluna vulgaris site type), treated with urea or ammonium nitrate with lime, was lower than that in the unfertilized soil. The same trend was also observed in samples of theEmpetrum-Calluna site type 14 years after fertilization. In the more fertileVaccinium myrtillus site type these rapidly-soluble N fertilizers had a long-term enhancing effect on the production of CO₂. Apatite and biotite eliminated the decreasing effect of urea on the production of CO₂. One reason for this might be the long-term increase in soil pH caused by apatite and biotite, or their constituents (Ca, Mg, K, P). Nitroform (a slow-releasing N fertilizer) had no statistically significant effect on the production of CO₂ in soil samples from any of the forest types. Despite the high N mineralization in the samples from nitroform fertilized soils there was no nitrification, and the high content of total N indicated that after nitroform fertilization the losses of N were low.The correlation between the net mineralization values for C (CO₂ production) and N was poor. However, multiple linear regression analysis, which also took into account the effect of nutrients and pH, indicated that there was a link between the mineralization of C and N.     

Confirmation of the chromosomal localization of human lamp genes and their exclusion as candidate genes for Salla disease

Summary Salla disease is an inherited lysosomal storage disorder caused by accumulation of free sialic acid in the lysosomes. Lamp genes, lamp A and lamp B (lysosome associated membrane proteins), are the first known genes encoding for human lysosomal membrane proteins. Absence of linkage in a large group of families shows that lamp genes are not involved in Salla disease. The lamp genes were localized, using Southern hybridization in hamster — human hybrid cell panels, to chromosomes 13 (lamp A) and X (lamp B).     

Chloroplast DNA variation inAnemone s. lato (Ranunculaceae)

Chloroplast DNA of seven species belonging toAnemone (sectt.Omalocarpus, Anemonidium, andAnemonanthea),Hepatica, andPulsatilla have been analyzed by restriction enzymes. According to the dendrogram constructed, the sections ofAnemone and the generaHepatica andPulsatilla seem to be evolutionary approximately equidistant to each others. This supports the concept that these groups should be treated on a similar taxonomic level, either as genera or subgenera.     

Spatial patterns and relationships between phytoplankton, zooplankton and water quality in the Saimaa lake system, Finland

The interactions between phytoplankton and zooplankton were studied in two large lakes in the Saimaa lake system, Finland. Both are subjected to substantial waste water loading, and exhibit a clear trophic gradient between the loaded and unloaded areas. The phytoplankton and zooplankton were compared in terms of composition, abundance and biomass at 34–39 stations located in different parts of the lakes. At least four mechanisms were thought to affect the composition of plankton communities: (1) the amount of nutrients (trophic gradient), (2) grazing of algae by herbivores, (3) the effect of the algal species composition on feeding by zooplankters (large, colonial algae in the more loaded parts of the lakes) and (4) the regeneration and reorganization of nutrients.     

Mismatch Repair Genes on Chromosomes 2p and 3p Account for a Major Share of Hereditary Nonpolyposis Colorectal Cancer Families Evaluable by Linkage

Two susceptibility loci for hereditary nonpolyposis colo-rectal cancer (HNPCC) have been identified, and each contains a mismatch repair gene: MSH2 on chromosome 2p and MLH1 on chromosome 3p. We studied the involvement of these loci in 13 large HNPCC kindreds originating from three different continents. Six families showed close linkage to the 2p locus, and a heritable mutation of the MSH2 gene was subsequently found in four. The 2p-linked kindreds included a family characterized by the lack of extracolonic manifestations (Lynch I syndrome), as well as two families with cutaneous manifestations typical of the Muir-Torre syndrome. Four families showed evidence for linkage to the 3p locus, and a heritable mutation of the MLH1 gene was later detected in three. One 3p-linked kindred was of Amerindian origin. Of the remaining three families studied for linkage, one showed lod scores compatible with exclusion of both MSH2 and MLH1, while lod scores obtained in the other two families suggested exclusion of one HNPCC locus (MSH2 or MLH1) but were uninformative for markers flanking the other locus. Our results suggest that mismatch repair genes on 2p and 3p account for a major share of HNPCC in kindreds that can be evaluated by linkage analysis.     

Genetic mapping of the erythropoietin receptor gene

We describe a novel, highly informative (polymorphism information content, PIC, = 0.86) simple sequence repeat polymorphism at the 5 end of the gene encoding the human erythropoietin receptor (EPOR) previously assigned to 19pl3.2 by in situ hybridization. Fourteen different allelic size variants were identified in 12 families of the CEPH (Centre d'Etude du Polymorphisme Humain) family panel of 40 families. In pairwise linkage 16 of the 65 chromosome 19 markers reported to the CEPH database gave a lod score exceeding 3.0 when tested against EPOR. The most likely location of EPOR within a framework of 10 markers including orientation and information on reported physical assignments was pter-[INSR-D1 9S177-D19S176]-D 19S24-LDLR-EPOR-cen-D-19S7-D19S49-D19S75-D19S47-APOC2-qter, placing EPOR as the most proximal of the tested loci on the short arm. On an 11-point map the position and order for all other loci except INSR were supported by the data with odds exceeding 1,000:1. The polymorphism at the 5 end of EPOR should provide a useful landmark marker for future mapping studies of this region.     

Distribution and disappearance of the radiolabeled carbon derived from L-arginine and taurine in the mouse

L-arginine and taurine are still in the center of physiological and pharmacological research. Although the fate of nitrogen of both compounds and of the ³⁵S-taurine is well-documented, the fate of the carbon skeleton has not been elucidated yet. We studied the organ distribution of ¹⁴C arginine and ¹⁴C taurine over time in the mouse using whole body autoradiography with densitometric image analysis. We describe different organ distribution patterns. Kidney, heart, lung, the Harderian gland, the central nervous system, intestine and testis showed a comparable pattern of arginine disappearance in contrast to rapid disappearance in the salivary gland and the accumulation pattern in bone and spleen. Data on ¹⁴C taurine of liver, kidneys, lung, testis and Harderian gland resembled the arginine pattern; Accumulation of taurine carbon was found in salivary gland, bone, intestine, heart and brain. Our studies challenge and demand further related studies to obtaining more information on the fate of the carbon skeleton of these amino acids.     

Processing of McCoy cell cultures infected with Chlamydia trachomatis: sequential isolation of chlamydial elementary bodies and lipopolysaccharide

Abstract Triton X-100 (TX100) enhances the liberation of chlamydial elementary bodies (EB) from host cells and dissolves the host cell membrane. In the presence of TX100 only differential centrifugation is needed to isolate reasonably pure EBs. The remaining high-speed supernatant still contains a large part of the chlamydial lipopolysaccharide (LPS), which can be isolated with the standard phenol-chloroform-petroleum ether extraction.