摘要:

AbstractUsing electrofusion of protoplasts from different dihaploid potato breeding clones, 308 somatic hybrids, i.e. 16.7% of the totally regenerated plants, were obtained. The results indicate that factors such as ‘combining ability’ strongly influence hybrid formation in these intraspecific fusion experiments. Hybrid identification was predominantly carried out by isoenzyme analysis of the peroxidases and/or esterases in polyacrylamide‐gradient gel electrophoresis. Further confirmation of the hybrid character was obtained by scoring phenotypic markers (petal colour, stem anthocyanin production, tuber characteristics, etc.) and, in some combinations, by evaluating tolerance against the herbicide metribuzin and nematode resistance againstGlobodera rostochiensis(Ro 1). The successful inheritance of metribuzin tolerance and nematode resistance confirm that monogenic dominant inherited traits are combined in the hy

ISSN:0932-8629    

DOI:10.1111/j.1438-8677.1992.tb00278.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractAnther‐derived suspension cultures ofHordeun vulgareL. were cryopreserved by slow cooling and storage in liquid nitrogen for up to 55 days. Cells were pre‐cultivated in L3 suspension medium supplemented with sorbitol. For freeze preservation the cells were treated with different combinations of cryoprotectant agents such as DMSO, proline, glycerol and sucrose. After rapid thawing high viabilities of up to 77% could be achieved. Cell growth commenced 2‐ 3 weeks later. The frequency of plantlet regeneration w

ISSN:0932-8629    

DOI:10.1111/j.1438-8677.1992.tb00279.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractAn acyltransferase from cell cultures ofChenopodium rubrumwas purified 515‐fold with a 2.5 % recovery. This enzyme catalyzes the transfer of hydroxycinnamic acids from 1–0‐hydroxycinnamoyl‐/β‐glucose to the C‐2 hydroxy group of glucuronic acid of amaranthin (betanidin 5‐O‐glucuronosylglucose). Theinvivoproducts formed are celosianin I (4‐coumaroylama‐ranthin) and celosianin II (feruloylamaranthin). The enzyme can be classified as l‐0‐hydroxycinnamoyl‐β‐glucose: amaranthin O‐hydroxycinnamoyl‐transferase (EC 2.3.1.‐). Its molecular weight was determined by gel filtration column chromatography to be ca. 69.5 kDa. Maximal rate of product formation was found to be at pH 5.6. The isoelectric point of the enzyme was at pH 4.7. The reaction temperature maximum was at 37 °C and the apparent energy of activation was calculated to be 44.5kJ mor−1. The enzyme showed a Vmaxof 910pkat (mg protein)−1with amaranthin as acceptor and feruloylglucose as acyl donor. The ratios ofVmax/Kmvalues for sinapoyl‐, feruloyl, caffeoyl‐ and 4‐coumaroylglucoses were found to be 100:56:56:40. Donor competition experiments support the conclusion that one single enzyme is responsible for the ester formation with the different hydroxycinnamic acids. From the possible acceptors tested, only amaranthin (15S configuration) and isoamaranthin (15R) were esterified withKmvalues of 280 and 800 μM, respectively. Catalytic effectivity (Vmix/Km) was found at a relative ratio 15S:15Rof 100:42. Betanin (betanidin 5‐O‐glucoside) and gomphrenin I (betanidin 6‐O‐glucoside) were not accepted. Some other acylated betacyanin‐containing members of four families of the Caryophyllales were investigated and showed the same type of hydroxycinnamoyltransferase activity with 1‐O‐hydroxycinnamoylglucose as a

ISSN:0932-8629    

DOI:10.1111/j.1438-8677.1992.tb00280.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractCell suspension cultures ofLycopersicon peruvianum(Solanaceae) were established as well‐growing photoautotrophic, photomixotrophic and heterotrophic cultures and their growth parameters were characterized. Elicitor‐induced responses of these cultures to the tomato pathogenFusarium oxysporumf. sp.lycopersiciwere investigated after treatment of cells with autoclaved mycelium and culture filtrate of this fungus. The dominant reaction was an enhanced incorporation of phenolic constituents in the plant cell wall. Among the nine phenolics released by alkaline hydrolysis the most prominent compounds were p‐hydroxybenzaldchyde, vanillin, p‐coumaroyltryamine, feruloyltyramine, p‐coumaric acid and ferulic acid. Phenolic incorporation in cell walls resulted in increased stability of cells against protoplasting with microbial enzymes. Chlorogenic acid, as the main soluble phenolic compound, showed differential accumulation in the three cell cultures lines as well as an elicitor‐induced transient decrease. In heterotrophic cells decrease of chlorogenate occurred concomitant with accumulation of caffeoyl‐ and p‐coumaroylshikimate as well as increased activities of p‐coumaroyleoenzyme A: shikimic acid p‐coumaroyltransferase. Upon elicitation increased activities of phenylalanine ammonia lyase and changes in peroxidase activities wore also detected. Sesquiterpenoid phytoalexines were not produced by either one of the cell culture lines and levels of tomatine were not significantly affe

ISSN:0932-8629    

DOI:10.1111/j.1438-8677.1992.tb00281.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractFour types of unicellular cyanobacteria were classified by pigment composition and cell size. These originated from the picoplankton fraction of Lake Constance, Germany. β‐Carotene and zeaxanthin were found to be the main carotenoids of threeSynechococcusisolates. In this group, coccoid forms with phycocyanin‐rich phycobilisomes also produce caloxanthin and nostoxanthin, which are xanthophylls with 3 and 4 hydroxy groups, respectively. In addition, these rare carotenoids are observed in rod‐formingSynechococcusisolates which contain phycoerythrin‐rich phycobilisomes, but they are very low or absent in the coccoid phycoerythrin‐rich isolates. Due to size and pigment content the coccoid forms are similar toSynechococcus leopoliensis(SAUG B 1402‐1, formerlyAnacystis nidulans) andS. rubescens(SAUG B 3.81) while the rod‐forming isolates differ fromS. elongatus(PCC 6716) in phycobilisome composition.The isolate BO 8402 was tentatively assigned toSynechocystisbut differs in pigment composition from all strains described as yet. The green cultures exhibited a faint red glow due to an unusual highin vivoautofluorescence from phycocyanin. Neither were phycobilisomes found in a standard preparation nor was allophycocyanin present. The most abundant carotenoids are β‐carotene and caloxanthin, while zeaxanthin, with 12 % of all colored carotenoids, is low.All forms described in this paper lack complementary chromatic adaptation, indicating that the pigment composition is a reliable parameter to identify these fr

ISSN:0932-8629    

DOI:10.1111/j.1438-8677.1992.tb00282.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractIn white light of 33.2 μmol . m−2. s−1oxygen evolution ofChlorella kessleriis about 30 % higher after growth in blue light than after growth in red light of the same quantum fluence rate. When determined by the light‐induced absorbance change at γ 820 nm, blue light‐adapted cells possess about 60% more reaction centres per total chlorophyll in photosystem II. Correspondingly, the cells exhibit about 30% more Hill activity of PS II. Conversely, red light‐adapted cells contain relatively more reaction centres and higher electron flow capacities of photosystem I. The distribution of total chlorophyll among the pigment‐protein complexes, CPI, CPIa, CPa, and LHC II, corresponds to these data. There is more chlorophyll associated with the light‐harvesting complex of PS II, LHC II, in cells under blue light conditions, but more chlorophyll bound to both complexes of PS I, CPI and CPIa, in cells under red light conditions. The respective ratios of chlorophyll a/chlorophyll b of all complexes are identical for blue and red light‐adapted cells. This results in a higher relative amount of chlorophyll b in blue light‐adapted cells.Total carotenoids per total chlorophyll are increased by 20% in red light‐adapted cells. Their distribution among the pigment‐protein complexes is unknown, however the ratios of lutein, neoxanthin and violaxanthin extractable from LHC II are different in blue (32.1:35.9:32.0) and in red (51.4:26.7:21

ISSN:0932-8629    

DOI:10.1111/j.1438-8677.1992.tb00283.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractIn addition to glutathione (γ‐GluCysGly), many species of the family Poaceae have another tripeptide which has the amino acid sequence γ‐GluCysSer. This thiol was isolated from etiolated leaves of wheat (Triticum aestivumL. cv. Star). Its structure was elucidated by quantitative amino acid analysis after total hydrolysis and by partial hydrolysis with carboxypeptidase A and γ‐glutamyltranspeptidase. The content of γ‐GluCysSer in the leaves ofT. aestivumis increased by incubation with sulfate and is severely diminished by incubation with buthionine sulfoximine, a specific inhibitor of γ‐glutamylcysteine synthetase. Oxidized γ‐GluCysSer is reduced by yeast glutathione reductase with a rate somewhat lower than for glutathione, but the new tripeptide is not a substrate of glutathione‐S‐transferase from equine liver.Besides homoglutathione (γ‐GluCysßAla), a tripeptide found in plants of the order Fabales, the tripeptide γ‐GluCysSer is the second homologue of gl

ISSN:0932-8629    

DOI:10.1111/j.1438-8677.1992.tb00284.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractIn a field‐study with approx. 150‐year‐old spruce trees, seasonal changes in thiol composition and content, sulfate content, and oxtractable activities of enzymes of sulfate reduction and assimilation were analyzed in needles and buds and were related to developmental processes during flushing. GSH was the predominant thiol in spruce needles throughout the year, with maximum contents of more than 400nmol g FW−1during winter and minimum contents of less than 200 nmol g FW−1during summer. Negative correlation of changes in GSI1 contents during winter and spring with air temperature showed a low correlation coefficient (r =– 0.55), suggesting minor significance of GSH in frost protection. Drastic changes in thiol contents during flushing suggested that GSH accumulated in the previous year's needles during winter supports the growing needles with reduced sulfur. Sulfate and other substrates for sulfate assimilation appeared to be available in buds and the new needles. An external supply with reduced sulfur may still be required because of insufficient activities of enzymes of sulfate reduction and assimilation, esp. ATP‐sulfurylase and APS‐s

ISSN:0932-8629    

DOI:10.1111/j.1438-8677.1992.tb00285.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractBiochemical and physiological properties of adenosine 5′‐phosphosulfate sulfotransferase, a key enzyme of assimilatory sulfate reduction, from spruce trees growing under field conditions were studied. The apparent Kmfor adenosine 5′‐phosphosulfate (APS) was 29 ± 5.5μM, its apparent Mrwas 115,000. 5′‐AMP inhibited the enzyme competitively with a Kiof 1 mM, but also stabilized it. MgS04at 800 mM increased adenosine 5′‐phosphosulfate sulfotransferase activity by a factor of 3, concentrations higher than lOOOmM were inhibitory. Treatment of isolated shoots with nutrient solution containing 1 or 2 mM sulfate, and 3 or 10 mM glutathione, respectively, induced a significant decrease in extractable adenosine 5′‐phosphosulfate sulfotransferase activity over 24h, whereas GSH as well as S2‐up to 5mM cysteine and up to 200 mM SO32‐had no effect on thein vitroactivity of the enzyme. As with other enzymes involved in assimilatory sulfate reduction, namely ATP sulfurylase (EC 2.7.7.4), sulfite reductase (EC 1.8.7.1) and O‐acetyl‐L.‐serine sulfhydrylase (EC 4.2.99.8), adenosine 5′‐phosphosulfate sulfotransferase was still detected at appreciable activities in 2‐ and 3‐year‐old needles. Adenosine 5′‐phosphosulfate sulfotransferase activity was low in buds and increased during shoot development, parallel to the chlorophyll content. The enzyme activity was characterized by an annual cycle of seasonal chang

ISSN:0932-8629    

DOI:10.1111/j.1438-8677.1992.tb00286.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractEnvelope membranes from chloroplasts contain UDP‐sulfoquinovose: diacylglycerol sulfoquinovosyltransferase which catalyses the final step in sulfolipid assembly.In situproduced diacylglycerol served as radioactive acceptor to measure enzymatic activity. With this assay, several enzymatic parameters were investigated. The enzyme, which has maximal activity at pH 7.5, was stimulated by magnesium ions due to a decrease of the Kmfor uridine 5′‐diphospho‐sulfoquinovose from 80pM(no magnesium) to 10 μM (5 mM magnesium). This stimulation had a Kmof 0.7 mM magnesium and may be relevant in light/dark modulation of the enzymatic activity. The lower efficiency of guanosine 5′‐diphospho‐sulfoquinovose observed before can be ascribed to a higher Kmof this sugar nucleotide (400 μM). Under optimized and linearized conditions the sulfoquinovosyltransferase displayed about 10% of the activity of the UDP‐galactose: diacylglycerol galactosyltransferase which competes in the same membrane system for diacylglycerols. Addition of acidic lipids, such as sulfolipid and phosphatidylglycerol, to envelope membranes resulted in an inhibition of the sulfoquinovosyltransferase, whereas the galactosyltransferase was not affected.In vivothis may contribute to an adjustment of the sulfolipid proportion in plastid membranes. In contrast to the galactosyltransferase the sulfoquinovosyltransferase did not discriminate against the dipalmitoyl molecular species of diacylglycerol when offered together with the oleoyl‐palmitoyl species. Under conditions when oleoyl‐palmitoyl‐and dipalmitoyl‐diacylglycerols were synthesized with concurrent conversion to monogalactosyl and sulfoquinovosyl diacylglycerol, the sulfolipid was highly enriched in the fully saturated species. This may explain the occurrence of dipalmitoyl species in sulfolipids

ISSN:0932-8629    

DOI:10.1111/j.1438-8677.1992.tb00287.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY