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R Grumet

Publications and source records attributed to R Grumet.

11 recordsLinked to original sources
PubMed2000

Interaction between zucchini yellow mosaic potyvirus RNA-dependent RNA polymerase and host poly-(A) binding protein.

Viral replication depends on compatible interactions between a virus and its host. For RNA viruses, the viral replicases (RNA-dependent RNA polymerases; RdRps) often associate with components of the host translational apparatus. To date, host factors interacting with potyvirus replicases have not been identified. The Potyviridae, which form the largest and most economically important plant virus family, have numerous similarities with the animal virus family, the Picornaviridae. Potyviruses have a single-stranded, plus sense genome; replication initiates at the viral-encoded, 3' poly-(A) terminus. The yeast two-hybrid system was used to identify host plant proteins associating with the RdRp of zucchini yellow mosaic potyvirus (ZYMV). Several cDNA clones representing a single copy of a poly-(A) binding protein (PABP) gene were isolated from a cucumber (Cucumis sativus L.) leaf cDNA library. Deletion analysis indicated that the C-terminus of the PABP is necessary and sufficient for interaction with the RdRp. Full-length cucumber PABP cDNA was obtained using 5' RACE; in vitro and Escherichia coli-expressed PABP bound to poly-(A)-Sepharose and ZYMY RdRp with or without the presence of poly-(A). This is the first report of an interaction between a viral replicase and PABP and may implicate a role for host PABP in the potyviral infection process.

Amino Acid Sequence↗
PubMed1997

Molecular cloning of mannose-6-phosphate reductase and its developmental expression in celery.

Compared with other primary photosynthetic products (e.g. sucrose and starch), little is known about sugar alcohol metabolism, its regulation, and the manner in which it is integrated with other pathways. Mannose-6-phosphate reductase (M6PR) is a key enzyme that is involved in mannitol biosynthesis in celery (Apium graveolens L.). The M6PR gene was cloned from a leaf cDNA library, and clonal authenticity was established by assays of M6PR activity, western blots, and comparisons of the deduced amino acid sequence with a celery M6PR tryptic digestion product. Recombinant M6PR, purified from Escherichia coli, had specific activity, molecular mass, and kinetic characteristics indistinguishable from those of authentic celery M6PR. Sequence analyses showed M6PR to be a member of the aldo-keto reductase superfamily, which includes both animal and plant enzymes. The greatest sequence similarity was with aldose-6-phosphate reductase (EC 1.1.1.200), a key enzyme in sorbitol synthesis in Rosaceae. Developmental studies showed M6PR to be limited to green tissues and to be under tight transcriptional regulation during leaf initiation, expansion, and maturation. These data confirmed a close relationship between the development of photosynthetic capacity, mannitol synthesis, and M6PR activity.

Amino Acid Sequence↗
PubMed1992

A quick and inexpensive method for removing polysaccharides from plant genomic DNA.

A quick and inexpensive method has been demonstrated to remove polysaccharide contamination from plant DNA. Isolated plant genomic DNA with polysaccharide contaminants was dissolved in TE (10 mM Tris-HCl, pH 7.4, 1 mM EDTA) with NaCl ranging from 0.5-3.0 M, then precipitated with two volumes of ethanol. Most of the polysaccharides were removed effectively in a single high-salt precipitation at 1.0-2.5 M NaCl. At 3.0 M NaCl, the salt precipitated out of solution. Purified DNA was easily digested by either HindIII or EcoRI and was satisfactory as a template for PCR. The results show that high-salt precipitation effectively removed polysaccharides and their inhibitory effects on restriction enzyme and Taq polymerase activity.

DNA↗
PubMed1990

cDNA cloning and sequence analysis of the 3'-terminal region of zucchini yellow mosaic virus RNA.

The 3' half of the RNA of the cucurbit potyvirus zucchini yellow mosaic virus (ZYMV) was genetically cloned and the cDNA sequence of a portion of the putative RNA polymerase gene, the complete coat protein gene and the 3' untranslated region was determined. The coat protein and putative polymerase genes are both part of a continuous open reading frame as is the case for other potyviruses whose genomes are expressed as polyproteins. The Q/S protease cleavage site for the N terminus of the coat protein was deduced by alignment of the coat protein and polymerase genes with other potyviral sequences. The resulting protein has 279 amino acids and a calculated Mr of 31,214. The predicted amino acid sequence indicates a ZYMV-unique N-terminal region and potyvirus-characteristic central and C-terminal regions. These data also verify that ZYMV is distinct from the cucurbit potyvirus watermelon mosaic virus 2.

Amino Acid Sequence↗
PubMed1987

Pathogen-derived resistance to viral infection using a negative regulatory molecule.

The principle of pathogen-derived resistance (the use of pathogen-derived genes to interfere with the pathogenic process and thereby confer disease resistance to the host) has been put forward as a broadly applicable conceptual tool for use in the genetic engineering of resistance to pathogens and parasites. It was previously predicted that four mechanisms of pathogen-derived resistance could be established using the bacteriophage QB and its host, Escherichia coli, as a model system. This paper demonstrates and helps ellucidate the first of these mechanisms by using a viral regulatory protein, the QB coat protein, to block viral replication. The QB coat protein gene was transferred to susceptible E. coli. Expression of this gene had no obvious detrimental effect on the host. Low-level, constitutive expression of the coat protein conditions very high levels of resistance to QB infection. The resulting resistance is not associated with RNA interference or loss of pili as attachment sites, and does not appear to be associated with premature encapsidation. This low-level expression of the QB coat protein also produces an intermediate level of resistance to the closely related phage SP, but fails to protect against the unrelated phage f2. Thus the resistance does not result from a generalized antiviral host response induced by the presence of the coat protein. We conclude that the QB coat protein blocks viral infection, as was predicted, due to its action as a negative regulatory molecule. The use of negative regulatory molecules may provide an effective mechanism for use in the genetic engineering of pathogen-derived resistance.

Capsid↗
PubMed1985

Betaine synthesis in chenopods: Localization in chloroplasts.

PLANTS FROM SEVERAL FAMILIES (CHENOPODIACEAE, GRAMINEAE, COMPOSITAE) ACCUMULATE BETAINE (GLYCINE BETAINE) IN RESPONSE TO SALT OR WATER STRESS VIA THE PATHWAY: choline --> betainal (betaine aldehyde) --> betaine. Betaine accumulation is probably a metabolic adaptation to stress. Intact protoplasts from leaves of spinach (Spinacia oleracea) oxidized [(14)C]choline to betainal and betaine, as did protoplast lysates. Upon differential centrifugation, the [(14)C]choline-oxidizing activity of lysates sedimented with chloroplasts. Chloroplasts purified from protoplast lysates by a Percoll cushion procedure retained strong [(14)C]choline-oxidizing activity (1-3 nmol/mg of chlorophyll per hr), although the proportion of the intermediate, [(14)C]betainal, in the reaction products was usually higher than for protoplasts. Isolated chloroplasts also readily oxidized [(14)C]betainal to betaine (20-100 nmol/mg of chlorophyll per hr). Light increased the oxidation of both [(14)C]choline and [(14)C]betainal by isolated chloroplasts approximately 3-fold; this light-stimulation was abolished by 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU). Similar results were obtained with another chenopod (Beta vulgaris) but not with pea (Pisum sativum), a species that accumulates no betaine. The chloroplast site for betaine synthesis in chenopods contrasts with the mitochondrial site in mammals.

Journal Article↗
PubMed1981

Ripening behavior of wild tomato species.

Nine wild tomato species were surveyed for variability in ripening characteristics. External signs of ripening, age of fruit at ripening, and ethylene production patterns were compared. Ethylene production was monitored using an ethylene-free air stream system and gas chromatography. Based on these ripening characteristics, the fruits fell into three general categories: those that change color when they ripen, green-fruited species that abscise prior to ripening, and green-fruited species that ripen on the vine.The fruits that change color, Lycopersicon esculentum var. cerasiforme, Lycopersicon pimpinellifolium and Lycopersicon cheesmanii, exhibited a peak of ethylene production similar to the cultivated tomato; there were differences, however, in the timing and magnitude of the ethylene production. Peak levels of ethylene production are correlated with age at maturity. For the two species that abscise prior to ripening, Lycopersicon chilense and Lycopersicon peruvianum, ability to produce ethylene varied with stage of maturity. The two species differed from each other in time of endogenous ethylene production relative to abscission, suggesting differences in the control mechanisms regulating their ripening. For two of the green-fruited species that ripen on the vine, Lycopersicon chmielewskii and Lycopersicon parviflorum, ethylene production was correlated to fruit softening. For Lycopersicon hirsutum and Solanum pennellii, however, ethylene production was not correlated with external ripening changes, making questionable the role of ethylene as the ripening hormone in these fruits.

Journal Article↗
PubMed1979

Ribosome-thylakoid association in peas: influence of anoxia.

Isolated pea chloroplast thylakoids ordinarily have ribosomes attached which survive sequential washes. Extensive in vivo loss of these thylakoidbound ribosomes occurred if the pea plants were placed in the dark without O(2) for 2 or more hours. This loss was indicated from measurements of both the total thylakoid-bound RNA levels, and the capacity for amino acid incorporation into proteins on the addition of soluble enzymes for protein synthesis. Stroma ribosome profiles lost any indication of polysome structure due to the same anoxic treatment in vivo. The return of ribosomes to the thylakoids when plants were placed in the light in air occurred over an 8-hour time course. This return was prevented by lincomycin, spectinomycin, and chloramphenicol, indicating a requirement for protein synthesis steps in the stroma at some point in the reassociation process.

Journal Article↗
PubMed1972

Morita therapy.

Explore the source record for details and available documents.

Behavior Therapy↗
PubMedDate not supplied

Genetic engineering of potyvirus resistance using constructs derived from the zucchini yellow mosaic virus coat protein gene.

Three versions of the zucchini yellow mosaic virus (ZYMV) coat protein gene were engineered for expression in plants: the full-length coat protein sequence, the conserved core portion of the gene, and an antisense version. These constructs were introduced into muskmelon (Cucumis melo) and tobacco plants (Nicotiana tabacum) via Agrobacterium tumefaciens-mediated transformation; gene expression was verified by Northern and Western analysis. Transgenic R0 and R1 muskmelon plants expressing the full-length coat protein gene exhibited apparent immunity to ZYMV infection: There was a lack of symptom development during a 3-mo observation period and no measurable virus accumulation as determined by ELISA. Melon plants expressing the core or antisense constructs showed a several-day delay of systemic symptom development and reduction in virus titer. Furthermore, transgenic R1 tobacco plants expressing the full-length coat protein, core, or antisense constructs of ZYMV, a nonpathogen of tobacco, showed a short delay in symptom development and reduced virus titer when inoculated with the heterologous potyviruses, potato virus Y, and tobacco etch virus. The transgenic tobacco plants were not protected against the non-potyvirus, tobacco mosaic virus.

Base Sequence↗