Planta
The yeast trehalose-6-phosphate synthase gene (TPS1) was engineered under the control of the cauliflower mosaic virus regulatory sequences (CaMV35S) for expression in plants. Using Agrobacterium-mediated transfer, the gene was incorporated into the genomic DNA and constitutively expressed in Nicotiana tabacum L. plants. Trehalose was determined in the transformants, by anion-exchange chromatography...
Abstract. Four distinct integration/translocation routes into/across thylakoid membranes have recently been deduced for nuclear-encoded polypeptides of the photosynthetic membrane. Corresponding information for the plastid-encoded protein complement is lacking. We have investigated this aspect with in-organello assays employing chimeric constructs generated with codon-correct cassettes for genes of...
Abstract. Leaf tissues of barley (Hordeum vulgare L. cv. Salome) respond to methyl jasmonate (JaMe) treatment with a characteristic pattern of gene expression. Jasmonate-induced proteins (JIPs), such as leaf thionins (jip15 gene product) and ribosome-inactivating proteins (jip60 gene product), rapidly accumulate. Their genes are transiently transcriptionally activated, as shown here by the determination...
Cytokinins induce two specific morphological alterations in mosses: (i) the differentiation of a tipgrowing cell into a three-faced apical cell (the so-called bud), and (ii) the division of chloroplasts. In a developmental mutant of the moss Physcomitrella patens (Hedw.) B.S.G. (mutant PC22) impeded in both cellular differentiation (bud production) and chloroplast division, addition of cytokinin (N...
Four distinct integration/translocation routes into/across thylakoid membranes have recently been deduced for nuclear-encoded polypeptides of the photosynthetic membrane. Corresponding information for the plastid-encoded protein complement is lacking. We have investigated this aspect with in-organello assays employing chimeric constructs generated with codoncorrect cassettes for genes of plastid-encoded...
Distribution of post-translationally modified tubulins in cells of Nicotiana tabacum L. was analysed using a panel of specific antibodies. Polyglutamylated, tyrosinated, nontyrosinated, acetylated and Δ2-tubulin variants were detected on α-tubulin subunits; polyglutamylation was also found on β-tubulin subunits. Modified tubulins were detected by immunofluorescence microscopy in interphase microtubules,...
Abstract. A cDNA clone encoding a WD-40 repeat protein (BGB1) was characterized in Brassica napus L. The clone contained an open reading frame of 327 amino acid residues almost entirely composed of seven segments of WD-40 repeats. Among the WD-40 repeat proteins, BGB1 showed high similarity (63% identity) to a rat intracellular receptor for protein kinase C (RACK1) that functions in the translocation...
In order to determine why the activated methyl cycle is up-regulated in plants undergoing defence responses to fungal pathogens we have monitored the utilisation of methyl groups derived from methionine in cell-suspension cultures of alfalfa (Medicago sativa L.) treated for various times with fungal elicitor, by carrying out a parallel labelling study with [35S]methionine and [methyl-3H]methionine...
A comparison of carbon metabolism in the constitutive crassulacean acid metabolism (CAM) plant Kalanchoë daigremontiana Hamet et Perr. and the C3-CAM intermediate Clusia minor L. was undertaken under controlled environmental conditions where plants experience gradual changes in light intensity, temperature and humidity at the start and end of the photoperiod. The magnitude of CAM activity was manipulated...
Phototropism of rice (Oryza sativa L.) coleoptiles induced by unilateral blue light was characterized using red-light-grown seedlings. Phototropic fluence-response relationships, investigated mainly with submerged coleoptiles, revealed three response types previously identified in oat and maize coleoptiles: two pulse-induced positive phototropisms and a phototropism that depended on stimulation time...
Abstract. A recessive temperature dependent shooty mutant (tds) of Nicotiana tabacum L. (W38) is described. The mutant phenotype is expressed at low temperature (21C). Mutant characteristics include thick, narrow leaves with abnormal mesophyll cells, short internodes, and near absence of apical dominance. Most plants remain vegetative and the occasional flower has petaloid stamens. High temperature...
Abstract. The capacity for HCO3 use by Porphyra leucosticta Thur. in Le Jolis grown at different concentrations of inorganic carbon (Ci) was investigated. The use of HCO3 at alkaline pH by P. leucosticta wasdemonstrated by comparing the O2 evolution rates measured with the O2 evolution rates theoretically supported by the CO2 spontaneously formed from HCO3 . Both external and internal carbonic anhydrase...
Analysis of nectar from leek (Allium porrum) flowers by SDS-PAGE revealed the presence of two major polypeptide bands of 50 kDa and 13 kDa, respectively. Using a combination of agglutination tests, enzyme assays and N-terminal sequencing, the polypeptides have been identified as subunits of alliin lyase (alliinase, EC 4.4.1.4) and mannose-binding lectin, respectively. The latter protein is particularly...
Abstract. Phototropism of rice (Oryza sativa L.) coleoptiles induced by unilateral blue light was characterized using red-light-grown seedlings. Phototropic fluence-response relationships, investigated mainly with submerged coleoptiles, revealed three response types previously identified in oat and maize coleoptiles: two pulse-induced positive phototropisms and a phototropism that depended on stimulation...
Abstract. The chemical composition of ethanolic and aqueous extracts from leafy galls produced after infection of Nicotiana tabacum L. plants with Rhodococcus fascians was drastically changed compared to uninfected controls. Chlorogenic acid was abundant both in uninfected and infected plants, but caffeic acid and another cinnamoyl analogue were new in leafy galls. The most pronounced product induced...
A recessive temperature dependent shooty mutant (tds) of Nicotiana tabacum L. (W38) is described. The mutant phenotype is expressed at low temperature (21 °C). Mutant characteristics include thick, narrow leaves with abnormal mesophyll cells, short internodes, and near absence of apical dominance. Most plants remain vegetative and the occasional flower has petaloid stamens. High temperature (30 °C)...
Abstract. In a search for membrane docking proteins interacting with Zea mays auxin-binding protein (ABP1) the binding of purified ABP1 to maize coleoptile plasma-membrane vesicles was investigated. Concentration-dependent, saturable binding of ABP1 to the membrane vesicles was observed in binding assays using 108106M ABP1. Biotinylated ABP1 was displaced from the membrane binding sites by competition...
Abstract. The NADH-dependent nitrate reductase (NR, EC 1.6.6.1) in roots of hydroponically grown barley seedlings was extracted, desalted and the activity measured in buffer containing either Mg2+ (10mM) or EDTA (5mM). The former gives the actual NR activity (NRact) equivalent to dephospho-NR, whereas the latter gives the maximum NR capacity of the dephospho-form (NRmax). Both values together permit...
Abstract. The conducting elements of phloem in angiosperms are a complex of two cell types, sieve elements and companion cells, that form a single developmental and functional unit. During ontogeny of the sieve element/companion cell complex, specific proteins accumulate forming unique structures within sieve elements. Synthesis of these proteins coincides with vascular development and was studied...
Abstract.Kalancho pinnata (Lam.) Pers. (Crassulaceae), a succulent-leaved crassulacean-acid-metabolism plant, was grown in open-top chambers at ambient and elevated (two times ambient) CO2 concentrations under natural conditions at the Smithsonian Tropical Research Institute, Republic of Panama. Nocturnal increase in titratable acidity and nocturnal carbon gain were linearly related, increased with...