The locus controlling liver GM1(NeuGc) expression is mapped 1 cM centromeric to H-2K

The polymorphic variation of liver GM1 (NeuGc) ganglioside was found in inbred strains of the mouse. The genetic analysis using C57BL/10 (GM1-negative) and SWR (GM1-positive) mice revealed that a single autosomal gene (Ggm-1) was involved in the expression of liver GM1(NeuGc) and that C57BL/10 mice lacking GM1(NeuGc) expression carried a defective gene on Ggm-1. Since our previous study on H-2 congenic mice indicated that Ggm-1 was linked to the H-2 complex, in this study we measured recombination frequencies among Ggm-1, Go-1 and H-2K in the backcross progeny between (C57BL/10 × SWR)F₁ and C57BL/10. Ggm-1 was mapped 1 cM centromeric to H-2K on chromosome 17.Abbreviations used in this paper GM1(NeuGc) Gal1-3GalNAc1-4 (NeuGc2-3)Gal1-4Glc1-ceramide - GM2(NeuGc) Gal1-4(Neu Gc2-3)Gal1-4Glc1-ceramide - GM3(NeuGc) NeuGc2-3Gal1-4 Glc1-ceramide - GD1a(NeuGc) NeuGc2-3Gal1-3GalNAc1-4 (NeuGc2-3)Gal1-4Glc1-ceramide     

Biochemical and genetic heterogeneity of staphylococcal protein A

Abstract We investigated the biochemical and genetic heterogeneity of protein A from Staphylococcus aureus . SpA genes ( spas ) of various strains were heterogeneous when detected as Dra I and Eco RV fragments of chromosomal DNA. Polymerase chain reaction using primers to detect DNA encoding the IgG-binding domains in spa revealed that they numbered between 2 and 5. Protein A from several S. aureus strains showed two types of reactivities to immunoglobulins in normal canine serum according to the number of active domains.     

Identification of Genes Associated with Chlorophyll Accumulation in Flower Petals

Plants have an ability to prevent chlorophyll accumulation, which would mask the bright flower color, in their petals. In contrast, leaves contain substantial amounts of chlorophyll, as it is essential for photosynthesis. The mechanisms of organ-specific chlorophyll accumulation are unknown. To identify factors that determine the chlorophyll content in petals, we compared the expression of genes related to chlorophyll metabolism in different stages of non-green (red and white) petals (very low chlorophyll content), pale-green petals (low chlorophyll content), and leaves (high chlorophyll content) of carnation (Dianthus caryophyllus L.). The expression of many genes encoding chlorophyll biosynthesis enzymes, in particular Mg-chelatase, was lower in non-green petals than in leaves. Non-green petals also showed higher expression of genes involved in chlorophyll degradation, including STAY-GREEN gene and pheophytinase. These data suggest that the absence of chlorophylls in carnation petals may be caused by the low rate of chlorophyll biosynthesis and high rate of degradation. Similar results were obtained by the analysis of Arabidopsis microarray data. In carnation, most genes related to chlorophyll biosynthesis were expressed at similar levels in pale-green petals and leaves, whereas the expression of chlorophyll catabolic genes was higher in pale-green petals than in leaves. Therefore, we hypothesize that the difference in chlorophyll content between non-green and pale-green petals is due to different levels of chlorophyll biosynthesis. Our study provides a basis for future molecular and genetic studies on organ-specific chlorophyll accumulation.     

Release of the Outer Membrane Vesicles from Vibrio cholerae and Vibrio parahaemolyticus

We found numerous small vesicles released from the cell by thin sectioning of the plate culture of Vibrio cholerae and V. parahaemolyticus fixed with the freeze-substitution technique. From the broth media of exponentially growing bacteria we could collect the vesicles by the centrifugation but not enough without fixation. The vesicles are encompassed with a membrane structure similar to the outer membrane of these bacteria. The anti-O (Inaba) serum reacted with the surface of the vesicles and the inside of the vesicle are generally filled with an electron-dense mass.     

Synthesis of 19-hydroxy-[7-2H2]androstenedione for human metabolism studies

19-Hydroxyandrostenedione (19-OHA), highly labeled with deuterium at position 7, was synthesized from unlabeled androstenediol diacetate. The deuterium labels were introduced into the 7-keto compound with dichloroaluminum deuteride to obtain [7-2H2]androstenediol. The labeled androstenediol diacetate was converted to the labeled 19-OHA by a five-step sequence without appreciable loss of deuterium. The labeled 19-OHA is useful as an internal standard for gas chromatography-mass spectroscopy analysis of the endogenous levels and as a tracer for in vivo metabolic studies.     

A locus controlling the activity of UDP-galactose:GM2(NeuGc) galactosyltransferase in mouse liver is linked to the H-2 complex

Genetic polymorphism in the expression of the G_M1(NeuGc) ganglioside has been shown in the liver of inbred strains of mice. Through analysis of the gangliosides of H-2 congenic and recombinant strains, this polymorphism was demonstrated to be controlled by a locus mapped left outside of the H-2 complex on chromosome 17, and the locus was assumed to control the level of the activity of G_M1(NeuGc) synthetase, UDP-galactose:G_M2(NeuGc) galactosyltransferase (E.C.2.4.1.62) [Hashimotoet al., J Biochem (1983) 94:2049-54].In the present study we analyzed the genetic linkage between the activity of the galactosyltransferase and the H-2 haplotype. For this purpose, we selected two inbred strains of mice, WHT/Ht and BALB/c, because they have different levels of the transferase activity and show different H-2 haplotypes; the specific activity of the transferase obtained with BALB/c was one-eighth of that with WHT/Ht, and BALB/c expressed the la.7 antigen as one of the products encoded in their H-2^d complex, whereas WHT/Ht did not. To analyze the linkage between these two phenotypes, WHT/Ht were mated with BALB/c to obtain the F₁ mice, and the female F₁ mice were then backcrossed to WHT/Ht. It was found that one half of the backcross generation expressed the la.7 antigen derived from BALB/c and had a significantly lower specific activity of the transferase than that of WHT/Ht, while the other half did not express the la.7 antigen but had the same specific activity of the transferase as that obtained with WHT/Ht.These results suggest that the locus controlling the level of the transferase activity in mouse liver is linked to the H-2 complex on chromosome 17.Abbreviations NeuGc N-glycolylneuraminic acid The ganglioside nomenclature is based on the system of Svennerholm, J Neurochem (1963) 10:613-23. The sialic acid species present is shown in parentheses after the ganglioside abbreviation.     

Effects of inorganic nitrogen application on the dynamics of the soil solution composition in the root zone of maize

The effect of inorganic nitrogen (N) fertilizer on the ionic composition of the soil solution under maize (Zea mays L.) was studied. A pot experiment was carried out with two treatments combined factorially, with or without N application (Ca(NO₃)₂; +N and –N treatments, respectively), and with or without plants. Three looped hollow fiber samplers were installed in each pot to sample soil solutions nondestructively from the root zone, seven times during the 50-day growth period. Plants were harvested on the 50th day, and their nutrient contents determined.Effects of N fertilizer on the soil solutions were observed by the first sampling, 2 days after sowing. The concentrations of Ca and NO₃ ^– and electrical conductivity (EC) increased significantly in the +N treatments as direct effects of fertilizer application. In addition, the concentrations of Mg, K, Na and H⁺ also increased and that of P decreased significantly as indirect effects caused by the re-establishment of chemical equilibria. This suggested the greater supply as well as the greater possibility of leaching loss not only of NO₃ ^– but also of Ca, Mg and K. In the treatments with plants, the concentrations of NO₃ ^–, Ca, Mg and K decreased with time and pH increased significantly compared with the unplanted soil. The depletion of N in the soil solution roughly agreed with the amount of N taken up by the plant. The depletions of K from the soil solution amounted to less than 10% of the amount of the K taken up, suggesting intensive replenishment of K from exchange sites in the soil. Depletions of Ca and Mg were several times higher than the amounts taken up, indicating that the depletions resulted from the adsorption of the divalent cations by the soil rather than uptake by plants. Because NO₃ ^– is hardly absorbed by exchange sites in soil and was the dominant anion in solution, it was concluded that NO₃ ^– had a major role in controlling cation concentrations in the soil solution and, consequently, on their availability for uptake by plants as well as their possible leaching loss. ei]H Marschner     

Differential distribution of ganglioside GM1 and sulfatide during the development of Xenopus embryos

A frozen section technique for frog oocytes was developed without using any organic solvent. It was applied to examine the distribution of acidic glycosphingolipids (ganglioside GM1 and sulfatide) in Xenopus oocytes, eggs and embryos by indirect immunofluorescence microscopy with specific monoclonal antibodies against the acidic glycolipids. Although glycolipids are generally present on the cell surface, GM1 and sulfatide were distributed in the cytoplasm of animal and vegetal hemispheres, respectively, of the fully grown oocytes and oviposited and fertilized eggs. In blastula, GM1 was present on the cell boundaries and in the Golgi of the blastomeres of animal hemisphere and marginal zone, whereas the staining of the outermost layer of animal blastomeres became faint or negligible at stage 9. Sulfatide in blastula was still observed in vegetal blastomeres. In gastrula, GM1 was distributed in the inner layer of ectoderm and the involuting mesoderm. In neurula, GM1 was concentrated in the dorsal midline including the closing neural tube, notochord and somites, while sulfatide was present in endoderm. The unique distribution of GM1 and sulfatide in oocytes, eggs and early embryos may help to elucidate one aspect of the biochemical bases laid on the animal–vegetal polarity.     

Mapping of the Gene for Machado-Joseph Disease within a 3.6-cM Interval Flanked by D14S291/D14S280 and D14S81, on the Basis of Studies of Linkage and Linkage Disequilibrium in 24 Japanese Families

The gene locus of Machado-Joseph disease (MJD) has recently been mapped within a 29-cM subregion of 14q chromosome. We did a linkage study of 24 multigenerational MJD Japanese pedigrees, in an attempt to narrow the candidate region of this gene. Pairwise and multipoint linkage analysis, together with haplotype segregation analysis, led to the conclusion that the MJD gene is located at the 6.8-cM interval between D14S256 and D14S81 (Z_max = 24.78, multipoint linkage analysis). D14S291 and D14S280, located at the center of this interval, showed no obligate recombination with the MJD gene (Z_max = 5.93 for D14S291 and 9.99 for D14S280). A weak, but significant, linkage disequilibrium of MJD gene was noted with D14S81 (P < .05) but not with D14S291 or D14S280. These results suggest that a 3.6-cM interval flanked by D14S291/D14S280 and D14S81 is the most likely location of the MJD gene and that it is closest to D14S81.