Reactions and resistance ofChenopodium species to tobacco mosaic virus

Chenopodium species react on infection with tobacco mosaic virus by the formation of chlorotic or necrotic lesions and later by the abscission of infected leaves. A transition of local infection into the stem has been observed exceptionally inChenopodium quinoa, C. hybridum, andC. rubrum, but no systemic infection of the leaves followed. Systemic infection was demonstrated only inC. polyspermum andC. murale. The recovery of new sprouts was demonstrated in C.murale in the late chronic phase of infection.     

Étude de quelques bacilles homolactiques isolés de vins

Résumé Les auteurs ont étudié 750 bactéries lactiques isolées de vins, en utilisant les tests et le système de classification de Rogosa et Sharpe. Parmi ce grand nombre de souches vingt-trois appartiennent au groupe des bacilles homolactiques et font l'objet du présent travail. Elles se répartissent de la façon suivante: 9 souches de Lactobacillus plantarum, 2 souches de Lactobacillus casei var. casei, 4 souches de Lactobacillus casei var. alactosus et 8 souches de Streptobacterium non classées, différentes des espèces précédentes.Les auteurs discutent la valcur de cette classification, lorsqu'on se place au point de vue technologique. Ils montrent qu'elle s'applique mal aux bactéries lactiques isolées de milieux fermentés acides comme le vin. Elle a peu d'intérêt pratique, car elle ne permet pas de repérer une souche et de prévoir par sa position systématique les constituants du vin que cette souche est susceptible de métaboliser.

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A study of some homofermentative lactic acid bacteria isolated from wines

Summary The authors have studied 750 strains of lactic acid bacteria isolated from wines. In this study the test and classification of Rogosa and Sharpe were used. Of the strains mentioned 23 belonged to the homolactie bacteria, including 9 strains of Lactobacillus plantarum, 2 strains of Lactobacillus casei var. casei, 4 strains of Lactobacillus casei var. alactosus, and 8 strains of a non-identified Streptobacterium species.The authors discuss the value of the classification mentioned from the point of view of wine technology. They conclude that it cannot be applied in the case of lactic acid bacteria isolated from acid fermentation products such as wine. It is only of little practical interest because it does not render the identification of the strains possible, nor does it permit a prediction of the wine constituents which the strains concerned are able to metabolize.

     

Neural cell recognition molecule F11: homology with fibronectin type III and immunoglobulin type C domains

We report here the complete cDNA sequence of F11 130 kd polypeptide, a chick neural cell surface-associated glycoprotein implicated in neurite fasciculation and elongation. The predicted protein sequence of 1010 amino acids includes an amino-terminal signal peptide and a carboxy-terminal hydrophobic stretch, which is compatible with the consensus motif for covalent attachment of glycosyl-phosphatidylinositol. Accordingly, F11 lacks an intracellular domain, which is consistent with evidence obtained from protease protection experiments on isolated microsomes. In addition, the molecule comprises six domains related to the immunoglobulin domain type C and four resembling fibronectin repeat type III. Both types of repeats resemble those present in neural cell adhesion molecules L1 and N-CAM. The possible identity of F11 with the chick neural glycoprotein contactin is discussed.     

Surface distribution of the mannose 6-phosphate receptors in epithelial Madin-Darby canine kidney cells

We have analyzed the surface polarity of both the cation-independent (CI-MPR) and the cation-dependent (CD-MPR) mannose 6-phosphate receptors in the epithelial Madin-Darby canine kidney (MDCK) cell line grown on polycarbonate filters. The surface localization was studied by plasma membrane domain-specific surface labeling methods and by confocal microscopy using MPR-specific antibodies. The CI-MPR was shown to be exclusively present on the basolateral cell surface. In contrast, the CD-MPR was expressed neither apically nor basolaterally. However, an intracellular pool of CD-MPR could be detected. In MDCKII-RCAr cells, cell surface CI-MPR was shown to recycle between the basolateral plasma membrane and the trans-Golgi network. After exogalactosylation, cell surface CI-MPR acquired sialic acid residues in a time-dependent manner. Furthermore, the basolateral CI-MPR was shown to be functional. Lysosomal enzymes, bearing the mannose 6-phosphate recognition marker, were taken up from the basolateral medium and endocytosed into the cells. Uptake of lysosomal enzymes from the apical side was insignificant and not MPR mediated. These results extend previous immunoelectron microscopic studies on the intracellular polarity of the CI-MPR (Parton, R. G., Prydz, K., Bomsel, M., Simons, K., and Griffiths, G. (1989) J. Cell Biol. 109, 3259-3272) which showed that the CI-MPR was present in basolateral early endosomes and in late endosomes but absent from apical early endosomes.     

Hypohidrotic ectodermal dysplasia

Summary A family carrying the X-linked gene for hypohidrotic ectodermal dysplasia (hereditary ectodermal polydysplasia or Christ-Siemens-Touraine syndrome) over three generations was monitored for more than 15 years. Two prenatal diagnoses were carried out by fetoscopy on skin biopsies. Polymorphic probes were used in the segregation analysis of the Xq11–21 region carried out on 30 members of the family. Current screening possiblitities for the carriers and prenatal diagnosis are discussed.     

Correlation between secreted and membrane-bound IgG in mouse myeloma cells transfected with chimeric immunoglobulin heavy and light chain genes

Mouse myeloma cells were transfected with pSV2-gpt and pSV2-neo based immunoglobulin expression vectors. Double transfectants were selected using the xanthine-guanine phosphoribosyl transferase (gpt) and the neomycin (neo) selection marker genes. A broad distribution in the level of mouse-human chimeric IgG expression was observed with series of independently isolated transfectoma clones. The relative amounts of secreted to membrane-bound antibodies correlated closely, which suggested, that fluorescence-activated cell sorting could be a valuable tool for the selection of high-yielding production cell lines. However, a single cycle of cell sorting did not steer the cloning process significantly toward cells that produce enhanced amounts of recombinant IgG. Only in cases in which the polyclonal transfectoma population contained a large percentage of nonproducing cells, these were successfully separated from the IgG-producing cell population. (c) 1996 John Wiley & Sons, Inc.     

A new missense mutation (Cys297→Phe) of the low density lipoprotein receptor in Italian patients with familial hypercholesterolemia (FHTrieste)

During a survey of the mutations of the low density lipoprotein receptor (LDL-R) gene in Italian patients with familial hypercholesterolemia (FH), we identified a novel point mutation, that creates a new EcoRI site at the 5 end of exon 7, in a heterozygous FH subject (FH-100). The sequence of a cDNA fragment encompassing exon 7 showed the presence of a GT transversion in codon 297; this created a new EcoRI site and produced a missense mutation, leading to a Cys₂₉₇Phe substitution in repeat A of the epidermal growth factor (EGF) precursor homology domain of LDL-R. Since the substitution of Cys₂₉₇ disrupts the intracellular transport of the LDL-R protein, as previously demonstrated by site-directed mutagenesis, we suggest that this mutation is the cause of FH in the FH-100 proband. We screened the DNA of 303 Italian FH patients by amplification of exon 7 from genomic DNA followed by digestion with EcoRI or by Southern blotting. Two individuals (FH-64 and FH-127) were found to be carriers of the Cys₂₉₇Phe mutation. Restriction fragment length polymorphism analysis demonstrated that, in two kindreds (FH-64 and FH-100), the haplotype in linkage with the Cys₂₉₇Phe mutation was the same, suggesting the presence of a common ancestor. The Cys₂₉₇Phe mutation has been designated FH_Trieste after the name of the city in Northern Italy from which probands FH-100 and FH-127 originate.