摘要:

AbstractThe thallus, pycnidia, and the structure and ontogeny of the ascocarp inAuriculora byssomorphaare described and illustrated. The ontogeny of the apothecia is characterized by the repeated formation of new hymenia within the subhymenial layer. The development of the first hymenium is gymnocarpous but thede novodifferentiation of new hymenia, each beneath the next older disintegrating one, gives rise to a peculiar type of secondary hemiangiocarpy. Portions of the decaying hymenia and adjacent subhymenial tissue frequently remain fastened to the apothecial margin and disc in the shape of ear‐like appendages or as superimposed layers. In aged apothecia such decaying tissue may form a sheath around the apothecial margin and on the disc. The systematic position of the genus is briefly discusse

ISSN:0932-8629    

DOI:10.1111/j.1438-8677.1990.tb00138.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

AbstractBiochemical and physiological characters of 5 symbioticChlorellastrains, 4 of them fromParamecium (Ciliata)and one fromAcanthocystis (Rhizopoda, Heliozoa), were studied. Four strains (3 fromParameciumand one fromAcanthocystis) belong to the same species. This is characterized by the presence of hydrogenase, no formation of secondary carotenoids, no growth on mannitol, requirements for thiamine and vitamin B12, and a G + C content of the DNA of 66.4–68.4 mol%; the limits of growth are at pH 5.5, at up to 1% NaCl, and at 26–30°C. The strains are somewhat heterogeneous in their utilization of inorganic nitrogen sources: only two of them are able to use nitrate, whereas all can grow with nitrite and ammonium. Thus, in two strains the nitrate‐reducing system — in contrast to nitrite reductase — seems to be defective. Another strain, which has been claimed to be fromParamecium, belongs toC. prot

ISSN:0932-8629    

DOI:10.1111/j.1438-8677.1990.tb00139.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

AbstractThreeGlycinegenotypes,G. maxcv. Williams,G. sojaPI 468397, andG. sojaPI 342434 in combination with the two rhizobial strainsBradyrhizobium japonicumUSDA 123 andRhizobium frediiUSDA 193 were analysed for phytoalexin concentration in the nodules. In the nodules of PI 468397/B. japonicumUSDA 123 a very strong glyceollin I accumulation occurred around 30 d.p.i. Ultrastructural analysis of these nodules revealed several symptoms of a severe plant defense response associated with plant cell death (hypersensitive reaction): The cytoplasm of the infected cells was degraded and organelles had vanished. The cell walls of the infected cells showed remarkable thickening. This plant defense response could only be observed in this strain/genotype interaction. The same strain did not elicit a phytoalexin accumulation in the other plant genotypes tested, indicating that this response occurs at the genotype‐specific level. This special character ofG. sojaPI 468397 is heritable as indicated by glyceollin I analysis of the nodules formed by F1 hybrids of PI 468397xWilliams inoculated withB. japonicumUSDA 123. The genotype/strain specific occurrence of the hypersensitive response in root nodules resembles the race/cultivar specific incompatibility of several plant‐pathogen interactions. This specificity, together with the phenomenon of the HR itself, points out the close physiological relationship between the late stages of the root nodule symbiosis and a plant/pathogen interact

ISSN:0932-8629    

DOI:10.1111/j.1438-8677.1990.tb00140.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

AbstractActivities of photosystems I and II were compared at a saturating irradiance in air‐ and 5% CO2‐adapted and adaptingChlamydomonas segnisat the active phase of photosynthesis during the cell cycle. PSII activity was 200% greater in air‐ than in 5% CO2‐adapted cells, while PSI activity was similar in both types of cells and matched the level of PSII activity in air‐adapted cells. As a result, air‐ and 5% CO2‐adapted cells were characterized by low and high PSI/PSII ratios, respectively. In air‐adapted cells, the greater PSII activity (rate of O2evolved) exceeded that of photosynthetic (Ps) O2evolution, resulting in a Ps/PSII ratio below unity. This was associated with higher levels of catalase activity, lowerl‐ascorbate content, and higher dehydro‐l‐ascorbate content than in 5% CO2‐adapted cells. During adaptation to air or 5% CO2for 6 h in light, PSI rather than PSII was sensitive to changes in the concentration of CO2, and the adapting cells acquired the characteristics of air‐ and 5% CO2‐adapted cells as indicated by PSI/PSII, Ps/PSII, catalase activity,l‐ascorbate and dehydro‐l‐ascorbate contents. The results are discussed in the light of changes in the molecular organization of the thylakoid membranes and enhanced non‐cyclic electron transport coupled with O2‐uptake (Mehler reaction) for the generation of the ATP required for CO2/HCO−3‐tr

ISSN:0932-8629    

DOI:10.1111/j.1438-8677.1990.tb00141.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

AbstractCells of pigment mutant C‐6D of the green algaScenedesmus obliquussynthesize only Chl a and precursors of carotenoids during heterotrophic growth in the dark. These cells exhibit high PSI‐activity per Chl and a low Chl/P700‐ratio. After transfer to light, Chl a, Chl b and carotenoids are formed with different kinetics.Analysis of chlorophyll fluorescence emission and excitation spectra revealed a sevenfold increase in the amount of the long wavelength antenna of PSI (720 nm) resulting in an increase in the absorption cross section of PSI during illumination. The underlying changes in molecular organization of PSI were investigated by sucrose density centrifugation of solubilized thylakoids after digitonin treatment and subsequent identification of the components by gel electrophoresis, HPLC and fluorescence. In dark grown cells one blue‐green band (0‐II) could be resolved. This band contained only Chl a and the reaction center complex of PSI, CPI.After 24 hours of illumination three pigmented zones and a small amount of free pigment were observed. One of the zones (24‐I) was identified as a light‐harvesting fraction containing the pigment‐protein complexes LHCP1and LHCP3. In the second fraction (24‐II) the reaction center complexes of PSI and PSII were found. The highest molecular weight fraction (24‐III) was enriched in PSI‐complexes of higher molecular weight and contained a high amount of long wavelength fluorescence antenna (720 nm) attributed to PSI. In contrast to band 24‐II which contained a high percentage of β‐carotene and a high Chl a/b‐ratio, the Chl a/b‐ratio of fraction 24‐III was lower and the xanthophyll content increased.Our data demonstrate an increase in the PSI‐unit size during chloroplast development in mutant C‐6D ofScenedesmus obliquus. Dark‐grown cultures have small functional PSI‐units composed of the chlorophylls involved in charge separation and the core antenna. This unit contains only Chl a and no carotenoids. After transfer to light Chl b and carotenoids are formed. Simultaneously with the appearance of carotenoids and Chl b, PSI‐complexes of higher molecular weight are synthesized indicating the addition of a

ISSN:0932-8629    

DOI:10.1111/j.1438-8677.1990.tb00142.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

AbstractThe light‐harvesting chlorophyll‐protein system of the phototrophic algaChlamydobotrys stellataconsists of the common photosystem II‐related chlorophyll a/b‐protein complex LHCII and a special photosystem I‐connected chlorophyll protein complex, called LHCa (Brandt et al. 1982, 1983) which is present after cultivation of the algae with acetate as carbon source and in absence of carbon dioxide. LHCII consists of three polypeptides (Mr.10327, 25.5 and 25), whereas only one polypeptide (Mr.10324) was obtained after polyacrylamide gel electrophoresis of LHCa. The specific LHCII‐precursor‐polypeptides (Mr.10338, 32, 26) were among the translation products of poly(A+)mRNA from autotrophic or photoheterotrophic algae. The LHCa‐precursor‐polypeptide (Mr30 000) was found when the alga had been cultivated in the presence of acetate. The data support the assumption that LHCa‐biosynthesis is controlled by the actual growth conditions at or close to the tr

ISSN:0932-8629    

DOI:10.1111/j.1438-8677.1990.tb00143.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

AbstractA DNA‐protein complex capable of RNA synthesis (transcriptionally active chromosome, TAC) was isolated from plastids of dark‐grown and blue light irradiated cell cultures ofChenopodium rubrum. The transcriptional activity of TAC increased rapidly upon irradiation of dark‐grown cells with blue light. Analysis of the RNA synthesized showed that plastid rRNA genes as well as genes coding for membrane and stroma proteins were specifically transcribed; their quantities depended on the developmental stage of the plastids produced by blue light exposure. Thein vitrotranscription rate seems to reflect fairly well thein vivosituation insofar as its enhancement in blue light irradiated cells is in good accordance with the observed steady‐state level of plastid mRNAs. The results obtained support the notion that the blue light‐dependent accumulation of plastid mRNAsin vivois caused by an increase in the transcription rate of the corresponding genes. Thus an alternative exists to the light‐induced transformation of etioplasts to chloroplasts in seedlings where primarily posttranscriptional and translational controls ar

ISSN:0932-8629    

DOI:10.1111/j.1438-8677.1990.tb00144.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

AbstractThe proteolytic degradation of unassembled small subunit polypeptides of ribulose‐1,5‐bisphosphate carboxylase and of the δ‐subunit of the coupling factor of photophosphorylation CF1were analyzed and comparedin vitroin the presence of stroma or membrane preparations from ribosome‐deficient plastids isolated from 32°C‐grown rye leaves (Secale cerealeL.). Extracts obtained from 70S ribosome‐deficient rye leaves after radioactive labeling were used as substrate source for the unassembled polypeptides. Soluble stroma as well as membrane preparations from isolated plastids contained proteolytic activities catalyzing the degradation of both the small subunits of ribulose‐1,5‐bisphosphate carboxylase and CF1‐δin vitro. Maximalin vitrodegradation was observed at pH 2–3 for the unassembled small subunits, but at pH 6–7 for the purified holoprotein of ribulose‐1,5‐bisphosphate carboxylase, and at pH 6.0 for unassembled CF1‐δ. Degradation of unassembled small subunits of ribulose‐1,5‐bisphosphate carboxylase at pH 3.0 was stimulated by Cu2+but not by Ca2+, Mg2+or ATP. At pH 3.0 the degradation of unassembled small subunits of ribulose‐1,5‐bisphosphate carboxylase was not inhibited by various protease inhibitors but was even stimulated. At pH 7.0 its degradation was inhibited by HgCl2and diazoacetyl nor‐leucine methyl ester + Cu‐acetate. The degradation of CF1‐δ was markedly inhibited by phenylmethylsulphonyl fluoride (PMSF) and to a lesser extent by 1,10‐phenanthroline. According to present results different proteolytic systems appear to be involved in the degradation of unassembled small subunits of ribulose‐1,5

ISSN:0932-8629    

DOI:10.1111/j.1438-8677.1990.tb00145.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

AbstractThe nitrogen‐fixing cyanobacteriumAnabaena variabilis(ATCC 29413) was cultivated as continuous culture under a 12 h: 12 h light‐dark cycle. In the light, photosynthetic activity resulted in a continuous increase in cellular glycogen content, followed by an almost complete dissimilation of the polysaccharide during the dark period. Nitrogenase activity, assayed by the acetylene reduction technique, was low at the end of the dark period and increased quickly upon illumination to reach a maximum after 4 to 6 h of light. The activity rapidly declined after darkening the culture. Increase and decrease of activity were accompanied by a change in the electrophoretic mobility of the Fe‐protein of nitrogenase (dinitrogenase reductase) indicative of enzyme modification being involved in the diurnal control of nitrogenase activity. Modification and demodification of the Fe‐protein were not coupled to the cell cycle since they followed darkening and illumination when the light or dark periods were changed. Addition of fructose increased nitrogenase activity even in darkness and caused demodification of the Fe‐protein. Ammonium chloride supplied at the onset of illumination slowed down the increase of nitrogenase activity. A delayed inhibition of the enzyme was accompanied by partial Feprotein modification only. The reaction was completed after transfer to darkness. The function of enzyme modification in maintaining a constant C: N ratio is discussed and a dominating role of carbohydrate supply in this regulation is indicated by the reported

ISSN:0932-8629    

DOI:10.1111/j.1438-8677.1990.tb00146.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

AbstractMicrobodies were isolated from the freshwater algaVaucheria sessilisas well as from a marineVaucheria. The organelles equilibrated on sucrose gradients at densities 1.23 g . cm−3and 1.24g . cm−3, respectively. On electron micrographs they showed an ovoid or spheroid shape with a diameter of 0.5 to 0.8 μm.Besides catalase, the peroxisomes of both algae possess glycolate oxidase and glutamate‐glyoxylate aminotransferase, but no other leaf‐peroxisomal enzymes. Instead, the enzymes malate synthase and isocitrate lyase, which are markers of glyoxysomes in higher plants, are constituents of the peroxisomes in the marine as well as in the freshwater alga.Citrate synthase, aconitase, malate dehydrogenase and enzymes of the fatty acid β‐oxidation pathway are located exclusively in the mitochondria. Therefore, the peroxisomes fromVaucheriado not belong to either the type of leaf peroxisomes or to the type of

ISSN:0932-8629    

DOI:10.1111/j.1438-8677.1990.tb00147.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY