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Query: UNIPROT:P06889 (Mol)
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Polyphenol oxidases (PPOs) of plants are copper metalloproteins which catalyze the oxidation of mono- and o-diphenols to o-diquinones. Although PPOs are believed to be primarily responsible for the deleterious browning of many fruit and vegetable crops and are thought to be involved in plant-pest interactions, direct evidence for these roles is lacking. We report the cloning of two PPO cDNAs from Solanum tuberosum leaves. These cDNAs exhibit 97% and 98% sequence similarity at the DNA and deduced amino acid levels, respectively. Putative copper-binding regions of both cDNAs are very similar to those of mammalian, bacterial and Neurospora tyrosinases. Both leaf PPO cDNAs appear to encode polypeptides which are processed to a mature molecular weight of 57,000. In potato leaves, petioles, roots, and flowers, PPO is encoded by ca. 2 kb transcripts. Leaf PPO mRNA is developmentally regulated and only detectable in young foliage. In contrast, the protein profile of immunologically detectable PPO remains constant from the apical node through the eleventh leaf node.
Plant Mol Biol 1993 Jan
PMID:cDNA cloning and expression of potato polyphenol oxidase. 767 63

Forty sea from French patients allergic to Cupressus sempervirens pollen were tested for cross-reactivities against Cry j I, Cry j II (major allergens of Cryptomeria japonica pollen) and other pollen allergens from botanically related plants. Seventy-three per cent of the sera reacted with either Cry j I or Cry j II, or with both of them. These IgE cross-reactions were blocked effectively by mAb 046 (anti-Cry j I) or N26, T27 (anti-Cry j II), and weakly by mAbs 052, 027 and 026 (anti-Cry j I). Furthermore, the IgE antibodies in two sera, #40 and #11, bound to peptide fractions obtained from enzyme-digested Cry j I, and mAb 027 could also bind to the fractions. Analyses of the amino acid sequences of the peptides revealed that reactive peptides contained "NGNATPQLTKNAGVLTCSLSKR" sequence and the third residue N3 was glycosylated, however, when the N3 was not glycosylated, the IgE antibodies did not react, but mAb 027 could. The glycosylation of the N3 might be required for IgE-binding to the peptides. Sugar component on the N3 residue was found to be 0.4 mol galactose, 1.3 mol mannose, 0.8 mol fucose and 2.0 mol N-acetyl-glucosamine. Cross-reactivities against other pollen allergens from botanically related plants were found in most of the sera. However, many of these reactivities were detected by sandwich ELISA but not by an ELISA using allergen-coated plates, indicating that it is important to select an appropriate ELISA procedure in order to detect an allergen or an IgE antibody to an allergen.
Mol Immunol 1993 Feb
PMID:Epitopes on Cry j I and Cry j II for the human IgE antibodies cross-reactive between Cupressus sempervirens and Cryptomeria japonica pollen. 767 86

The parallel fiber "en passant" synaptic endings of mouse cerebellar molecular layer have shown by means of transmission electron microscopy, the presence of an electron dense extravesicular material in samples perfused with Alcian blue. This alcianophilic material was digested in cerebellar tissue previously treated with testicular hyaluronidase, suggesting the presence of hyaluronic acid or chondroitin 4- or 6-sulphate. Freeze-fractured Rhesus monkey cerebellar cortex prepared for conventional scanning electron microscopy also revealed the presence in fractured synaptic varicosities of parallel fibers of a high mass density material, in which the synaptic vesicles are embedded. Examination of cryofractured primate cerebellar cortex coated with thin chromium films, 1-2 nm thick, in the high resolution field emission scanning electron microscope showed the SE-I topographic contrast of an extravesicular material deposited in axoplasmic matrix of fractured parallel synaptic endings. The precise localization of this material corresponds to that observed in transmission electron microscopy and conventional freeze-fracture scanning electron microscopy. These electron microscopic findings tend to agree with the omnipresence in several vertebrates of a presynaptic axoplasmic material, which seems to be proteoglycan in nature.
Cell Mol Biol (Noisy-le-grand) 1994 Sep
PMID:Proteoglycan ultracytochemistry and conventional and high resolution scanning electron microscopy of vertebrate cerebellar parallel fiber presynaptic endings. 781 87

Germline chimeric chickens were produced by transfer of primordial germ cells from White Leghorn to Barred Plymouth Rock, and vice versa. Blood was collected from stage 13-15 embryos and primordial germ cells were concentrated by Ficoll density gradient centrifugation. Approximately 200 primordial germ cells were injected into the bloodstream through the dorsal aorta of stage 14-15 recipient embryos from which blood had been drawn via the dorsal aorta prior to the injection. Intact embryos were also prepared as recipients for White Leghorns only. The manipulated embryos were cultured in recipient eggshells until hatching. Germline chimerism of the chickens reaching maturity was examined by mating them with Barred Plymouth Rocks and donor-derived offspring were identified based on their feather color. The efficiency of production of germline chimeras was 95% (19/20). When primordial germ cells were transferred from White Leghorn to Barred Plymouth Rock, the average frequency of donor-derived offspring was 81% for three male chimeras (96% for one female chimera), and it was approximately 3.5 times higher for transfer in the opposite direction (23% for 6 male chimeras). Removing blood from recipient embryos prior to primordial germ cell injection enhanced the frequency of donor-derived offspring by 10% in resulting male chimeras. Male chimeras produced donor-derived offspring more frequently (approximately 3.8 times) than female chimeras. Increases, decreases, or no changes were observed in the frequency of donor-derived offspring from the germline chimeras with increasing age.(ABSTRACT TRUNCATED AT 250 WORDS)
Mol Reprod Dev 1994 Oct
PMID:Production of germline chimeric chickens, with high transmission rate of donor-derived gametes, produced by transfer of primordial germ cells. 782 16

Sugar-binding proteins obtained from the peri-implantation uterine tissue have been thought in recent years to have significant roles in embryo implantation, where carbohydrate moieties of the protein are actively involved. Based on this rationale a mannose-containing glycoprotein/lectin (named uterine agglutinin or UA) was purified by Concanavalin A (Con A) affinity chromatography in a previous study. A modification of the original purification procedure to include a 33% ammonium sulfate fractionation improves the yield of the protein significantly. An alternative purification procedure by Mannan affinity matrix, indicates that apart from containing mannose, UA possesses mannose-binding properties as well. In this paper, we report some of the biochemical and more specifically, the carbohydrate-binding characteristics of UA. The protein is seen to contain mannose-6-phosphate (M-6-P)-binding sites, which is of importance since M-6-P receptors have a large number of biologically significant roles, including that of binding to growth factors. SDS-PAGE, gel filtration chromatography and alkaline PAGE indicate the homogenous nature of the protein with subunit molecular weights of 36 kDa and 19 kDa, and a native size of 64 kDa. Amino acid analysis shows glycine, glutamic acid and aspartic acid to be the major constituents. UA is a glycoprotein and shows presence of N-acetyl glucosamine and galactose, apart from mannose. De nove synthesis studies in the presence of tunicamycin show that the carbohydrate moiety of the glycoprotein is attached by N-linkage to the protein. Binding characteristics of the protein is studied quantitatively in which (125I)-labelled lectin is bound to Mannan-Sepharose affinity matrix.(ABSTRACT TRUNCATED AT 250 WORDS)
Mol Cell Biochem 1994 Aug 31
PMID:Carbohydrate-binding profile of a pregnancy-associated rat uterine glycoprotein. 784 92

Homeodomains (HDs) are DNA-binding domains that have been well characterized in animals, and HD proteins are thought to be regulators of transcription. To investigate the regulation of gene expression during somatic embryogenesis in carrot, an attempt was made to isolate cDNA clones that encode HD proteins. A cDNA library from carrot somatic embryos was screened with a degenerate oligonucleotide probe that corresponded to a conserved amino acid sequence of HDs, and one cDNA clone (CHB1) encoding an HD protein was isolated. The amino acid sequence deduced from the nucleotide sequence of this clone contained a putative leucine zipper motif adjacent to the anticipated HD. The homeodomain/leucine zipper (HD-Zip) sequence of this cDNA was used for further screening, and five additional independent clones (CHB2 through CHB6) were isolated. Although the HD-Zip sequences encoded by these clones were similar to each other, the sequences beyond the HD-Zip regions varied greatly. Transcripts corresponding to CHB1 through CHB6 were expressed at different times during somatic embryogenesis. In particular, transcripts corresponding to CHB2 were expressed in close association with the early development of embryos.
Plant Mol Biol 1995 Jan
PMID:Isolation and characterization of homeobox-containing genes of carrot. 786 85

The larval stage of the intestinal nematode, Trichinella spiralis, secretes and displays on its cuticle a number of antigenically cross-reactive glycoproteins. These so-called TSL-1 antigens induce a powerful antibody response in parasitized animals. In rats, anti-TSL-1 antibodies mediate a protective immunity that expels invading larvae from the intestine. The vast majority of anti-TSL-1 antibodies are specific for glycans. Although the biological functions of TSL-1 antigens are not known, the powerful effect of glycan-specific antibodies on the intestinal survival of T. spiralis suggests that they play an important role in parasite establishment. Little is known about the structures of the glycans present on the TSL-1 glycoproteins. Recent studies have suggested, however, that the antigens contain very unusual glycans (Wisnewski, N., McNeil, M., Grieve, R.B. and Wassom, D.L., Mol. Biochem. Parasitol., 61, 25-36, 1993). Sugar and linkage analysis of the combined secreted products unexpectedly showed that a major terminal sugar is tyvelose (3,6-dideoxy-D-arabino-hexose; Tyv) which has previously been found only in certain gram-negative bacterial lipopolysaccharides. In this paper, we report the first rigorous structural study of oligosaccharides released from TSL-1 antigens by peptide N-glycosidase F digestion. Using strategies based on fast atom bombardment mass spectrometry (FAB-MS), we have discovered a novel family of tri- and tetra-antennary N-glycans whose antennae are comprised of the tyvelose-capped structure: Tyv1,3GalNAc beta 1,4(Fuc alpha 1,3)GlcNAc beta 1-. Thus a major population of TSL-1 glycans contains clusters of hydrophobic terminal structures which are likely to be highly immunogenic.
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PMID:Novel tyvelose-containing tri- and tetra-antennary N-glycans in the immunodominant antigens of the intracellular parasite Trichinella spiralis. 788 Nov 73

Infection of an SV40 large-T antigen-"immortalized" human bronchial epithelial cell line with a Zip-v-Ha-ras retroviral vector resulted in a mass culture that was tumorigenic in athymic nude mice. A tumor cell line derived from passage of the mass culture in vivo, however, exhibited increased tumorigenicity and v-Ha-ras expression. To examine and compare the molecular events involving the ras oncogene during cell transformation in vitro and subsequent tumor formation in vivo, clonal cell populations were isolated from the v-Ha-ras-transformed mass culture. While the clonal cell lines exhibited diverse tumorigenic profiles, these differences did not correlate with v-Ha-ras expression. However, the expression of the activated ras gene, while not necessary for growth in vitro, did appear to be associated with a selective growth advantage in vivo. In addition, the modulation of gene amplification ability in these cells was not associated with the induction of tumorigenicity or v-Ha-ras expression.
Mol Carcinog 1994 Sep
PMID:Clonal variation of tumorigenic potential in v-Ha-ras-transformed human bronchial epithelial cells: relationship to ras oncogene expression and CAD gene amplification. 791 88

The lumazine synthase/riboflavin synthase complex of Bacillus subtilis consists of an icosahedral capsid of 60 beta subunits enclosing a triplet of alpha subunits. An X-ray structure of 0.32 nm resolution has been obtained for the icosahedral capsid of the native alpha 3 beta 60 complex [Ladenstein, R., Schneider, M., Huber, R., Bartunik, H. D., Wilson, K., Schott, K. & Bacher, A. (1988) J. Mol. Biol. 203, 1045-1070]. beta subunits were isolated after denaturation of the alpha 3 beta 60 complex and were subsequently reconstituted in a ligand-driven reaction yielding artifactual, hollow beta 60 capsids with icosahedral symmetry. Hexagonal crystals (space group P6(3)22) of the reconstituted capsids diffracted X-rays to a resolution of 0.32 nm. Crystallographic intensity data were obtained using synchrotron radiation. Freeze-etched electron-microscopic images and rotation function calculations showed that the hexagonal crystal forms of the artifactual beta 60 capsids and the native alpha 3 beta 60 complex are isomorphous. Orientation and translation parameters of the beta-subunit model were refined by XPLOR rigid-body refinement. The electron-density map was improved by cyclic icosahedral averaging and phase extension from 0.5-0.32 nm resolution. The beta-subunit structure was partially refined by energy minimization and crystallographic refinement (XPLOR) assuming strict icosahedral symmetry (final R factor 30.9% for data at 0.8-0.32 nm resolution). The topology and chain folding of the beta subunits in the artifactual beta 60 capsid are similar to the native alpha 3 beta 60 enzyme. Structural features of the substrate-binding site and the binding of the substrate-analogous ligand 5-nitro-6-ribitylamino-2,4(1H,3H)-pyrimidinedione are discussed. Ligand binding occurs at the pentamer interfaces and includes van der Waals' interactions and hydrogen bonding. The binding pocket shows a hydrophobic region which accomodates the pyrimidinedione ring and a hydrophilic region to which the ribityl side chain binds. Most amino acid residues involved in the active site are conserved as shown by sequence comparisons with the putative lumazine-synthase genes of Escherichia coli and Photobacterium leiognathi. In the final electron-density map, a residual density feature was tentatively assigned to a bound phosphate ion which mimics the binding of the second substrate, 3,4-dihydroxy-2-butanone 4-phosphate. This putative phosphate-binding site involves a highly conserved amino acid sequence containing three basic residues.
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PMID:The lumazine synthase/riboflavin synthase complex of Bacillus subtilis. X-ray structure analysis of hollow reconstituted beta-subunit capsids. 805 41

Quantitation of UV-induced DNA damages in nanogram quantities of non-radioactive DNA from irradiated plants by gel electrophoresis requires a prompt, efficient, high-yield method of isolating DNA yielding high-molecular-weight, enzymatically digestible DNA. To meet these criteria we devised a high-yield method for isolating from plant tissue, DNA whose single-strand molecular length is greater than about 170 kb. Leaf tissue is embedded in agarose plugs, digested with Proteinase K in the presence of detergent, and treated with phenylmethylsulfonyl fluoride (PMSF). The agarose plugs are then soaked with buffer appropriate to the desired enzyme treatment. Evaluation of the DNA on neutral and alkaline gels indicates its high molecular length and low frequency of single-strand breaks. The DNA can be digested with damage-specific and other endonucleases. The method is especially suitable for DNA damage quantitation, as tissue processing is carried out immediately after harvesting (allowing DNA lesion measurement at precisely known times after irradiation), and many samples can be easily handled at once. It should also be useful for molecular analysis of large numbers of plant samples available only in small quantities. We here use this method to quantitate DNA damage induced by 297 and 365 nm radiation, and calculate the relative damaging effects of these wavebands in today's solar spectrum.
Plant Mol Biol 1994 Feb
PMID:Isolation of high-molecular-weight plant DNA for DNA damage quantitation: relative effects of solar 297 nm UVB and 365 nm radiation. 812 89


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