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T Boller

Publications and source records attributed to T Boller.

At least 91 records · Page 5Linked to original sources
PubMed1991

Elicitor-induced ethylene biosynthesis in tomato cells: characterization and use as a bioassay for elicitor action.

The induction of ethylene biosynthesis by an elicitor partially purified from yeast extract was studied in suspension-cultured tomato (Lycopersicon esculentum Mill.) cells. Unstimulated cells produced little ethylene during exponential growth and even less in stationary phase. Treatment with elicitor stimulated ethylene biosynthesis 10-fold to 20-fold in the exponentially growing cells and more than 100-fold in stationary cells. Activities of both 1-aminocyclopropane-1-carboxylate (ACC) synthase, measured in vitro, and ethylene-forming enzyme (EFE), measured in vivo, increased strongly in response to elicitor treatments. During exponential growth, cells contained large pools of ACC, and the elicitor stimulated ethylene biosynthesis primarily through induction of EFE. In the stationary phase, cells contained almost no ACC, and the elicitor stimulated ethylene biosynthesis primarily through its effect on ACC synthase activity. Cordycepin did not affect the increase in activity of ACC synthase but blocked that of EFE, indicating that the former was posttranscriptionally regulated, the latter transcriptionally regulated. Removal of elicitor by washing or inactivation of a biotinylated derivative of the elicitor by complexation with avidin caused a rapid cessation of the increase in ACC synthase activity, suggesting that continuous presence of stimulus is necessary for the response. Using induction of ethylene production to measure amounts of elicitor, it was found that the elicitor disappeared from the incubation medium during the course of the treatment.

Journal Article↗
PubMed1991

Regulation of sucrose-sucrose-fructosyltransferase in barley leaves.

The activity of sucrose-sucrose-fructosyltransferase (SST), a vacuolar enzyme strongly induced by light in excised leaves of barley (Hordeum vulgare L.), rapidly declined even in continuous light upon feeding of cycloheximide (CHI). The rate of decline was similar to that observed in light-treated leaves that were placed into darkness, in the presence or absence of CHI. The protease inhibitor leupeptin totally stopped the decline in SST activity in the dark and caused a substantial increase in the rate of induction of SST activity by light. Feeding of sucrose prevented or even reversed the SST activity decay induced by darkness in the absence of CHI but did not stabilize SST activity in the presence of CHI. The results suggest that SST is continuously subjected to rapid, constant proteolytic degradation in the vacuole, and that the enhancement of SST activity in the light or upon feeding sucrose in the dark is due exclusively to de novo protein synthesis.

Journal Article↗
PubMed1990

K-252a inhibits the response of tomato cells to fungal elicitors in vivo and their microsomal protein kinase in vitro.

Two characteristic responses of plant cells to fungal elicitors, induction of phenylalanine ammonia-lyase activity and of ethylene biosynthesis, were studied in suspension-cultured tomato cells. Induction of both responses was completely blocked by 500 nM K-252a, a known inhibitor of mammalian protein kinases. About 100 nM K-252a caused half-maximal inhibition. In vitro, K-252a inhibited protein kinase activity in microsomal preparations from tomato cells. Inhibition was competitive with respect to ATP and had a Ki of about 15 nM. Thus, protein kinases sensitive to K-252a occur in plants and might be important for the plant's response to fungal elicitors.

Carbazoles↗
PubMed1990

Heat shock induces enzymes of trehalose metabolism, trehalose accumulation, and thermotolerance in Schizosaccharomyces pombe, even in the presence of cycloheximide.

Exponentially growing cells of the fission yeast, Schizosaccharomyces pombe, contained virtually no trehalose at 27 degrees C but rapidly accumulated large quantities during heat shock at 40 degrees C. Activities of trehalose-6-phosphate synthase and trehalase also increased upon heat shock. Thermotolerance of the cells, measured as survival at 52 degrees C, increased in parallel to trehalose accumulation and decreased in parallel to the trehalose levels when cells were shifted back to 27 degrees C. Trehalose levels, activities of enzymes of trehalose metabolism and thermotolerance strongly increased upon heat shock even in the presence of cycloheximide, indicating that none of these effects requires protein synthesis. The data support the hypothesis that trehalose acts as a thermoprotectant in Schizosaccharomyces pombe.

Cycloheximide↗
PubMed1990

Rapid protein purification using phenylbutylamine-Eupergit: a novel method for large-scale procedures.

Electrophoretic desorption was used to compare the protein binding capacities of some hydrophobic adsorbents [the phenylbutylamine (PBA) derivatives of Eupergit C and agarose and Phenyl-Sepharose] for low-pressure chromatography. The highest capacity was observed for the bifunctional adsorbent PBA-Eupergit. The hydrophobically adsorbed proteins can be selectively desorbed by decreasing the pH of the eluent due to electrostatic repulsion between positive charges on the adsorbed proteins and positively charged secondary amines on the adsorbent. This was used to purify 1500 U penicillin amidase from E. coli homogenates per gram wet weight of PBA-Eupergit in 50 adsorption-desorption cycles without organic solvents (greater than 90% yield, purification factor = 5.3).

Adsorption↗
PubMed1990

A method for the study of fungal growth inhibition by plant proteins.

A bioassay is described for the study of inhibitory activity of plant proteins on fungal growth. Fungal spores were germinated in liquid growth medium and pipetted into wells of a microtitre plate. Fungal growth was followed spectrophotometrically. The bioassay was tested using crude protein extracts from plant tissues known to have high activities of chitinase and beta-1,3-glucanase, and with purified enzymes. Crude protein preparations and combinations of the purified enzymes produced a temporary reduction of growth but no permanent growth inhibition.

Fungi↗
PubMed1990

Inactivation of stress induced 1-aminocyclopropane carboxylate synthase in vivo differs from substrate-dependent inactivation in vitro.

The activity of 1-aminocyclopropane carboxylate (ACC) synthase increased rapidly in tomato (Lycopersicon esculentum Mill.) leaf discs after vacuum infiltration, reached a maximum after about 30 minutes, and subsequently decayed with an apparent half-life of about 20 minutes. Aminoethoxyvinylglycine, a known inhibitor of ACC synthase, did not alter the apparent turnover of ACC synthase in vivo although it efficiently blocked inactivation of the enzyme by its substrate S-adenosylmethionine in vitro. Similar results were obtained, using a novel assay with permeabilized cells, for ACC synthase in tomato cell cultures treated with a fungal elicitor. The results indicate that inactivation of ACC synthase in vivo differs from substrate-dependent inactivation in vitro.

Journal Article↗
PubMed1989

Correlation of trehalose content and heat resistance in yeast mutants altered in the RAS/adenylate cyclase pathway: is trehalose a thermoprotectant?

Trehalose content and thermotolerance were closely correlated in wild type yeast (Saccharomyces cerevisiae) and in cyr1-2 and bcy1-1 mutants both during exponential growth at 27 degrees C and during heat shock at 40 degrees C. Trehalose levels were high when heat shock proteins (hsps) were expected to be induced and low when hsps were presumably absent. It was tried to uncouple trehalose biosynthesis and hsp-induction. Various non-heat stresses affected trehalose levels of wild type cells in a similar way as they would have affected hsps. However, no trehalose was accumulated when cells were treated with canavanine, a well-known inducer of hsps but not of the thermotolerant state.

Adenylyl Cyclases↗
PubMed1988

Chitinase cDNA cloning and mRNA induction by fungal elicitor, wounding, and infection.

Chitinase, which catalyzes the hydrolysis of beta-1,4 N-acetylglucosamine linkages of the fungal cell wall polymer chitin, is a component of the inducible defenses of plants. We show that chitinase synthesis is stimulated in bean (Phaseolus vulgaris L.) cell suspension cultures treated with fungal cell wall elicitors and in hypocotyls in response to infection with the fungus Colletotrichum lindemuthianum. Chitinase cDNA clones were isolated by antibody screening of a lambdagt11 cDNA library containing sequences complementary to poly A(+) RNA from elicited cells. The identity of these clones was confirmed by nucleotide sequence analysis and comparison of the deduced amino acid sequence with that determined for the amino-terminal sequence of bean chitinase. Elicitor causes a very rapid activation of chitinase transcription with a 10-fold stimulation after 5 minutes and 30-fold increase within 20 minutes. This leads to a marked, transient accumulation of chitinase transcripts with maximum levels 2 hours after elicitor treatment, concomitant with the phase of rapid enzyme synthesis. Chitinase transcripts also markedly accumulate in wounded and infected hypocotyls. Chitinase cDNA sequences hybridize to several genomic fragments suggesting there are several chitinase genes in the bean genome.

Journal Article↗
PubMed1988

Antifungal Hydrolases in Pea Tissue : I. Purification and Characterization of Two Chitinases and Two beta-1,3-Glucanases Differentially Regulated during Development and in Response to Fungal Infection.

Chitinase and beta-1,-3-glucanase activities increased coordinately in pea (Pisum sativum L. cv "Dot") pods during development and maturation and when immature pea pods were inoculated with compatible or incompatible strains of Fusarium solani or wounded or treated with chitosan or ethylene. Up to five major soluble, basic proteins accumulated in stressed immature pods and in maturing untreated pods. After separation of these proteins by chromatofocusing, an enzymic function could be assigned to four of them: two were chitinases and two were beta-1,3-glucanases. The different molecular forms of chitinase and beta-1,3-glucanase were differentially regulated. Chitinase Ch1 (mol wt 33,100) and beta-1,3-glucanase G2 (mol wt 34,300) were strongly induced in immature tissue in response to the various stresses, while chitinase Ch2 (mol wt 36,200) and beta-1,3-glucanase G1 (mol wt 33,500) accumulated during the course of maturation. With a simple, three-step procedure, both chitinases and both beta-1,3-glucanases were purified to homogeneity from the same extract. The two chitinases were endochitinases. They differed in their pH optimum, in specific activity, in the pattern of products formed from [(3)H]chitin, as well as in their relative lysozyme activity. Similarly, the two beta-1,3-glucanases were endoglucanases that showed differences in their pH optimum, specific activity, and pattern of products released from laminarin.

Journal Article↗
PubMed1988

Antifungal Hydrolases in Pea Tissue : II. Inhibition of Fungal Growth by Combinations of Chitinase and beta-1,3-Glucanase.

Chitinase and beta-1,3-glucanase purified from pea pods acted synergistically in the degradation of fungal cell walls. The antifungal potential of the two enzymes was studied directly by adding protein preparations to paper discs placed on agar plates containing germinated fungal spores. Protein extracts from pea pods infected with Fusarium solani f.sp. phaseoli, which contained high activities of chitinase and beta-1,3-glucanase, inhibited growth of 15 out of 18 fungi tested. Protein extracts from uninfected pea pods, which contained low activities of chitinase and beta-1,3-glucanase, did not inhibit fungal growth. Purified chitinase and beta-1,3-glucanase, tested individually, did not inhibit growth of most of the test fungi. Only Trichoderma viride was inhibited by chitinase alone, and only Fusarium solani f.sp. pisi was inhibited by beta-1,3-glucanase alone. However, combinations of purified chitinase and beta-1,3-glucanase inhibited all fungi tested as effectively as crude protein extracts containing the same enzyme activities. The pea pathogen, Fusarium solani f.sp. pisi, and the nonpathogen of peas, Fusarium solani f.sp. phaseoli, were similarly strongly inhibited by chitinase and beta-1,3-glucanase, indicating that the differential pathogenicity of the two fungi is not due to differential sensitivity to the pea enzymes. Inhibition of fungal growth was caused by the lysis of the hyphal tips.

Journal Article↗
PubMed1987

Rapid changes of heat and desiccation tolerance correlated with changes of trehalose content in Saccharomyces cerevisiae cells subjected to temperature shifts.

The trehalose content of exponentially growing Saccharomyces cerevisiae cells rapidly increased in response to a temperature shift from 27 to 40 degrees C and decreased again when the temperature was shifted back from 40 to 27 degrees C. These changes were closely correlated with increases and decreases in the thermotolerance and desiccation tolerance of the cells. Our results support the hypothesis that trehalose functions as a protectant against heat and desiccation.

Disaccharides↗
PubMed1984

Vacuolar localization of ethylene-induced chitinase in bean leaves.

The localization of ethylene-induced endochitinase was studied in bean (Phaseolus vulgaris L. cv Saxa) leaves. The specific activity of chitinase in mesophyll protoplasts isolated from the leaves was as high as in tissue homogenates, indicating that most of the enzyme was located intracellularly. Vacuoles isolated and purified from the protoplasts were found to contain most of the intracellular chitinase activity.

Journal Article↗
PubMed1984

Ethylene: Symptom, Not Signal for the Induction of Chitinase and beta-1,3-Glucanase in Pea Pods by Pathogens and Elicitors.

Infection of immature pea pods with Fusarium solani f.sp. phaseoli (a non-pathogen of peas) or f.sp. pisi (a pea pathogen) resulted in induction of chitinase and beta-1,3-glucanase. Within 30 hours, activities of the two enzymes increased 9-fold and 4-fold, respectively. Chitinase and beta-1,3-glucanase were also induced by autoclaved spores of the two F. solani strains and by the known elicitors of phytoalexins in pea pods, cadmium ions, actinomycin D, and chitosan. Furthermore, exogenously applied ethylene caused an increase of chitinase and beta-1,3-glucanase in uninfected pods. Fungal infection or treatment with elicitors strongly increased ethylene production by immature pea pods. Infected or elicitor-treated pea pods were incubated with aminoethoxyvinylglycine, a specific inhibitor of ethylene biosynthesis. This lowered stress ethylene production to or below the level of uninfected controls; however, chitinase and beta-1,3-glucanase were still strongly induced. It is concluded that ethylene and fungal infection or elicitors are separate, independent signals for the induction of chitinase and beta-1,3-glucanase.

Journal Article↗
PubMed1980

Effect of 1-Aminocyclopropane-1-Carboxylic Acid on the Production of Ethylene in Senescing Flowers of Ipomoea tricolor Cav.

Application of 1-aminocyclopropane-1-carboxylic acid (ACC) to rib segments excised from flowers of Ipomoea tricolor Cav. resulted in the formation of C(2)H(4) in greater quantities than produced under natural conditions. The ability of ACC to enhance C(2)H(4) production was independent of the physiological age of the tissue and its capacity to synthesize C(2)H(4) without applied ACC. When ACC was fed to rib segments that had been treated with [(14)C]methionine, incorporation of radioactivity into C(2)H(4) was reduced by 80%. Aminoethoxyvinylglycine and aminooxyacetic acid inhibited C(2)H(4) production in rib segments of I. tricolor but had no effect on ACC-enhanced C(2)H(4) production. Protoplasts obtained from flower tissue of I. tricolor did not form C(2)H(4), even when incubated with methionine or selenomethionine. They produced C(2)H(4) upon incubation with ACC, however. ACC-dependent C(2)H(4) production in protoplasts was inhibited by n-propyl gallate, AgCl, CoCl(2), KCN, Na(2)S, and NaN(3). ACC-dependent C(2)H(4) synthesis in rib segments and protoplasts was dependent on O(2), the K(m) for O(2) being 1.0 to 1.4% (v/v). These results confirm the following pathway for C(2)H(4) biosynthesis in I. tricolor. methionine [selenomethionine] --> S-adenosylmethionine [selenoadenosylmethionine] --> ACC --> C(2)H(4).

Journal Article↗
PubMed1979

Some properties of vacuoles isolated from Neurospora crassa slime variant.

A method for the isolation of vacuoles based on polybase induced lysis of protoplasts of the cell wall deficient Neurospora crassa slime variant is described. Isolated vacuoles are characterized by 12 to 50 times increased specific activities of several hydrolases as compared with the total homogenate of protoplasts. Total alpha-amino nitrogen, arginine, and polyphosphate are also greatly enriched in these vacuoles. Vacuoles are equipped with a permease for the transport of basic amino acids across the tonoplast.

Amino Acids↗