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1.
Five different species of known ecto-mycorrhizal fungi: Cenococcum geophilum, Amanita muscaria, Tricholoma aurantium, Rhizopogon luteolus and Rhizopogon roseolus were studied for their ability to metabolize the major components of plant cell walls. All strains were able to decompose 14C-labelled plant lignin, 14C-lignocellulose and 14C-DHP-lignin at a rate which was lower than the one observed for the known white rot fungi Heterobasidion annosum and Sporotrichum pulverulentum. Also 14C-(U)-holocellulose was relatively less degradable for the mycorrhizal fungi than for the white rotters. On the other hand, aromatic monomers like 14C-vanillic acid were decomposed to a much higher extent by two species of mycorrhizal fungi compared to the activity observed for Heterobasidion annosum. The results of the experiments reveal that these stains of mycorrhizal fungi are well able to utilize the major components of plant material and thus can contribute to litter decomposition in the forest floor. 相似文献
2.
Effects of shoot bending of apple trees on accumulation and translocation of14C-labelled assimilates
A. Mika 《Biologia Plantarum》1969,11(2):175-182
The translocation of14C-labelled assimilates from a single leaf in bent and intact apple shoots was studied in varying stages of shoot development. In actively growing shoots14C-labelled assimilates translocated from the treated leaf and accumulated mainly in the shoot apex. In moderately growing apple shoots radioactive assimilates were translocated from the treated leaf in both directions towards and down the shoot. In apple shoots showing only slight growth activity the14C-labelled assimilates were transported from the treated leaf mainly to the base of the shoot, stem and roots. Bending shoots changed the pattern of distribution of radioactive assimilates. Bending actively and moderately growing shoots resulted in higher concentration of 14-carbon in the shoot apex than in controls. In slowly growing and non-growing apple shoots bending caused a higher accumulation of radioactive assimilates in the bent section than in an equal section of control shoots. 相似文献
3.
Uptake and binding of dodine acetate by fungal spores 总被引:1,自引:0,他引:1
Uptake of the dodine cation from acetate solutions by conidia of Alternaria tenuis and Neurospora crassa was characterized by a rapid rate of sorption, a ‘Langmuir type’ adsorption isotherm, and independence of temperature: all of which suggests an ionic bonding mechanism. Metal cations competed with dodine for the anionic binding sites of the cell—regarded as carboxyl and phosphate groups—and dodine uptake also decreased as ionization of the carboxyl group was suppressed. Cell walls of A. tenuis had a greater capacity to bind dodine than did those of N. crassa. Binding at the cell wall may detoxify some of the large amount of dodine that must be accumulated by the spores to achieve toxicity. The dodine retained by N. crassa cell walls could not be exchanged or desorbed by washing and is probably bound covalently rather than by weaker ionic bonds. At sub-lethal concentrations there was no evidence that dodine disorganized cell wall structure. Disruption of spores which had been incubated with 14C-labelled dodine showed the fungicide to be associated with intra-cytoplasmic organelles. It is suggested that dodine reacts with the protoplast membrane so as to alter its permeability and allow more dodine to penetrate into the cytoplasm where it may destroy intracellular membrane structure. 相似文献
4.
Incorporation of organic compounds into cell protein by the obligate chemolithotrophs Nitrosomonas spec., Nitrosococcus oceanus, Nitrosococcus mobilis, Nitrosovibrio tenuis, Nitrosolobus spec., and Nitrosopira spec. was studied. In the presence of ammonia as energy source organic substrates were supplied. Distribution of 14C into cell amino acids arising from 14C-labelled glucose, Na-pyruvate, and Na-acetate was investigated. While carbon from glucose was distributed unrestricted, carbon from pyruvate preferably entered into the amino acids of the pyruvate and glutamate family and from acetate mainly into leucine and the glutamate family. Among the strains examined, slight differences were observed, but all should be included under group A of the scheme of Smith and Hoare (1977). 相似文献
5.
《Biochimica et Biophysica Acta (BBA)/Lipids and Lipid Metabolism》1988,958(1):81-92
Human HDL (1.070-1.210), doubly labelled with 3H/14C-labelled unesterified cholesterol and 3H-labelled esterified cholesterol were incubated for 1–5 h with monolayer cultures of human endothelial cells. HDL were preincubated for 60–120 min the presence of albumin and with/without purified phospholipase A2 (control HDL, phospholipase A2 HDL) before dilution in the cell culture medium. Average phosphatidyl-choline (PC) degradation was 62.10% ± 2.57% (range 45–80%). A purified lipase /phospholipase A1 from guinea pig pancreas was used in some experiments (range of PC hydrolysis: 16–70%). (1) 3H/14C-labelled unesterified cholesterol and 3H-labelled esterified cholesterol appeared in cells during 0–5 h incubations. Trypsin treatment allowed a simple adsorption of HDL onto the cell surface to be avoided, and most of the 3H-labelled esterified cholesterol transferred to cells was hydrolysed. Cell uptake of radioactive cholesterol increased as a function of HDL concentration but no saturation was achieved at the highest lipoprotein concentration used (200 μg cholesterol/ml). Flux of 3H/14C-labelled unesterified cholesterol was related to the cell cholesterol content, suggesting that it might partly represent an exchange process. The cell cholesterol content was slightly increased after 5 h incubation with HDL (+16%). (2) Pretreatment of HDL with purified phospholipase A2 doubled on average the amount of cell recovered 3H-labelled esterified cholesterol, while the flux of 3H/14C-labelled unesterified cholesterol was enhanced by 15–25%. Both transfer and cell hydrolysis of 3H-labelled esterified cholesterol were increased. A stimulation was also observed using purified lipase/phospholipase A1, provided that a threshold phospholipid degradation was achieved (between 27 and 45%). (3) Endothelial cells were conditioned in different media so as to modulate their charge in cholesterol. The uptake of 3H-labelled esterified cholesterol was found to be significantly higher in cholesterol-enriched cells compared to the sterol-depleted state. Finally, movements of 3H-labelled esterified cholesterol from HDL to endothelial cells were essentially unaffected by cell density or by the presence of partially purified cholesterol ester transfer protein. The possible roles of the transfer of HDL esterified cholesterol to endothelial cells and its modulation by phospholipases are discussed. 相似文献
6.
Production of polygalacturonases and pectinases from Sclerotinia sclerotiorum was induced in vitro by galacturonic acid. The inductive effect of galacturonic acid was abolished by the presence of glucose, leading to a basal
enzyme production. Zymograms of extracellular enzymes showed that galacturonic acid induced the synthesis of six polygalacturonase
and one pectin-methylesterase isoforms. Immunoblotting revealed that an exo-polygalacturonase and an exo-polymethylgalacturonase
were secreted in all conditions. They are not glucose repressed and not regulated by galacturonic acid. These constitutive
enzymes provide the pathogen with the inherent ability to release galacturonic acid from plant cell walls and to trigger inducible
enzyme synthesis.
Received: 1 December 1995 / Accepted: 3 January 1996 相似文献
7.
Summary Various benzoic acids 14C-labelled in para and meta methoxyl groups as well as (O-methyl-14C) p-methoxy cinnamic acid were tested for O-demethylation in cell suspension cultures of Phaseolus aureus Roxb. and Glycine max Merr. On the basis of 14CO2-formation and product analyses the O-demethylation reactions were shown to be specific for para methoxyl groups. A vanillate-O-demethylase known from microbial sources seemed to be absent in the plant cell cultures.In this and in an earlier publication (Berlin et al., 1971) some twenty 14C-labelled aromatic compounds were tested for catabolic reactions in the cell cultures, and here we report on the product analyses and the general pattern of distribution of radioactivity. Finally, some indications for compartmentalisation in connection with catabolic studies of aromatic compounds in plant cell cultures are discussed.Decarboxylation of substituted benzoic acids in the cell cultures is restricted to aromatic acids possessing a hydroxyl group in the para position. Only trace amounts of labelled CO2 were released from (carboxyl-14C)-anisic acid. This acid, however, was nearly quantitatively demethylated to p-hydroxybenzoic acid, which itself was decarboxylated to a considerable extent after being fed to cell suspension cultures. Similar differences in respect to decarboxylation were observed with syringic acid produced by demethylation of trimethoxybenzoic acid and syringic acid applied directly to the cell cultures. 相似文献
8.
A Gram-positive bacterium which was isolated from a Finnish soil and identified as a Nocardia sp., was able to decompose lignin and to assimilate lignin degradation products as a carbon source. It could release 14CO2 from 14C-labelled methoxyl groups, side chains or ring carbons of coniferyl alcohol dehydropolymers (DHP) and from specifically 14C-labelled lignin of plant material. Furthermore, it could release 14CO2 from phenolcarboxylic and cinnamic acids and alcohols labelled in the OCH3, COOH groups, side chain or aromatic ring carbons.Non-Common Abbreviations Used DHP
dehydropolymers of coniferyl alcohol 相似文献
9.
Jerzy Trojanowski Aloys Hüttermann Konrad Haider Joseph G. H. Wessels 《Archives of microbiology》1985,140(4):326-330
Protoplasts from a lignolytic fungus Fomes annosus were prepared through enzymatic hydrolysis of mycelium utilizing Novozym, a wall lytic enzyme preparation. Isolated protoplasts and living mycelium were compared in their ability to degrade 14C-labelled lignin related phenols and dehydropolymers of labelled coniferyl alcohol (synthetic lignin). The amounts of 14CO2 released from O14CH3-groups, 14C-2-side chains and 14C-rings by protoplasts was in the same range as those for intact mycelium. The methoxyl groups of synthetic lignin were more rapidly metabolized by protoplasts than by mycelium. When calculated in dpm of released 14CO2 per mg protein the decomposition of 14C-labelled synthetic lignin and lignin-related monomers in a hyphae-free system of protoplasts was considerable higher than that obtained by the intact mycelium. The presence of intact hyphae is thus not necessary for lignin degradation to occur.Non-common-abbreviations used DHP
Dehydropolymer of coniferyl alcohol
- LS
lignosulfonates prepared from DHP 相似文献
10.
The shoot apex or fruitlets of Jonathan apple trees grafted on M IX rootstock and grown in pots in a greenhouse were exposed to14CO2 in an assimilation chamber. The translocation of14C-labelled assimilates from treated organs to other parts of the plant was studied. It was found that a very small amount of14C-labelled compounds was translocated from the shoot apex and very young fruitlets to the shoot stem. Preliminary chromatographic studies show that the chemical composition of the labelled substances detected below assimilation chamber differs profoundly from that of those remaining in the supplied leaves. The results support the view that there exists a translocation of some substances, possibly regulators from the sink to the donor. 相似文献
11.
Masahiko Ishida Hideo Nagayama Kensuke Shimura 《Bioscience, biotechnology, and biochemistry》2013,77(6):1277-1283
Incorporation of 14C from various 14C-labelled compounds into vitamin B6 (abbreviate as B6) in a cell-suspension of B6-producing bacteria, Achromobacter cycloclastes A.M.S. 6021, was studied by using a newly designed purification procedure of the radioactive B6. The procedure consisted of Sephadex G–25 gel filtration, Dowex 50W–X8 column chromatography, Amberlite CG–50 column adsorption, powdered cellulose partition column chromatography, crystallization and sublimatography. It was observed that the labels both from 1,3- and from 2-labelled glycerol were clearly incorporated into B6 and the label of 14C-labelled γ-aminobutyric acid was also incorporated. The incorporation of 14C from 14C-labelled glycerol or γ-aminobutyric acid was affected by the addition of cold γ-aminobutyric acid or glycerol. The implication of these compounds as precursors of B6 was discussed. 相似文献
12.
Cell component fractions (14C-labeled) were prepared from bacterial and fungal cultures isolated from the Pawnee National Grassland in northeastern Colorado and tested for seasonal changes in degradability. The decomposition of cell component fractions was monitored from May to December of 1977 and during March of 1978, using soil samples taken at 2- to 3-week intervals. The release of 14CO2 from bacterial and fungal cell walls was inversely related (P < 0.01) to the soil moisture content. Except for cytoplasm isolated from an Aspergillus sp., all other cytoplasmic and polysaccharide fractions did not demonstrate a significant relationship between soil moisture and decomposability. In general, bacterial cell walls and polysaccharides were more susceptible to decomposition than fungal cell walls, although the seasonal changes in decomposability for both fractions were similar. These patterns of cell component utilization indicate that the decomposition of cell wall material may be more closely linked, on an inverse basis, to the availability of soil moisture and release of soluble, low-molecular-weight organics resulting from primary production events. 相似文献
13.
P. E. Kriedemann 《Planta》1969,85(2):111-117
Summary
3H-glucose was fed to excised Sultana grape berries via their pedicels for up to 5 hours. Autoradigraphy showed that the label was distributed throughout the fruit within 1 hour. Microautoradiography of tissue sections taken at a number of points showed that within the pedicel the walls of cortical cells had become heavily labelled, suggesting that the cortical cell walls offered a diffusion pathway for the solutes entering the vascular system from the external aqueous solution. Transport along the pedicel was confined to the central vascular tissue with little radioactivity occurring in the cortical cells. Within the pericarp, the vascular bundles and walls of nearby parenchyma cells had become heavily labelled, indicating that the labelled solute was present within the vicinity of cell walls. The general pattern of 3H-glucose accumulation by excised berries was similar to the deposition pattern of 24C-labelled photosynthate within attached fruit. 相似文献
14.
It was shown that Botrytis cinerea, an isolate infecting apples, secreted in vivo and in culture a variety of glycosidic hydrolases with substrate specificity towards the polysaccharides of cell walls. The following enzymes were partially separated by column chromatography on DEAE-Sepharose CL-6B: two cellulases, three xylanases, one arabinanase, polygalacturonase, β-glucosidase, β-xylosidase, β-galactosidase, β-mannosidase and α-galactosidase. The activity of glycosidic hydrolases tested was strongly inactivated by NBS and weaker by PCMB, tetranitromethan, dibromoacetophenon and Fe3+, The results indicate synergistic action of the obtained cellulase, xylanase, polygalacturonase and arabinanase in apple cell wall degradation. 相似文献
15.
Richard G. Buggeln 《Journal of phycology》1981,17(1):102-104
The translocation of 14C-labelled photoassimilate was studied in blades of the kelp, Alaria esculenta (L.) Grev., which had been surgically modified to produce source and sink regions of various sizes. Thirty cm above the blade base a 2.5 cm dia. section of the blade received a 1 h pulse of H14CO3?. Efflux of 14C-labelled photoassimilate from this “source disc” was monitored over the next 8 days using a Geiger-Müller detector probe. Accumulation of 14C-labelled solutes by a “sink disc” of similar diameter, 20 cm below the source disc, was also monitored. Rate of l4C efflux from the source disc was governed by two factors: (1) total sink size and (2) feed-back from competing sources. In the latter case, source export was depressed if the portion of the blade, just distal to the source disc, was present. While the initial 14C influx rate into the sink disc was greater when competing sinks were present, the total accumulation of 14C-photoassimilates was 2–3 times higher in the sink disc when competing sources were not present. Basipetal translocation velocity (1.3–1.7 cm h?1) was unaffected by competing sources and sinks. 相似文献
16.
Cappenberg Thom E. Hordijk Kees A. Jonkheer Gert J. Lauwen Jos P. M. 《Hydrobiologia》1982,91(1):161-168
The turnover and exchange rates, as well as the diffusion processes, concerning the input and output of carbon compounds at
the mud-water interface, were studied. The carbon input rates were derived from the annual sedimentation rates of particulate
organic matter (about 1 100 kg C · yr−1). The nature of the sedimented POC, and its breakdown pathways and turnover rates towards important metabolic intermediates
in methanogenesis, were examined. The breakdown kinetics ofChlorella cell walls, a dominant green alga in Lake Vechten, was studied using U-14C-labelled cell walls. The breakdown of the cell walls appears to the rate-limiting step in anaerobic mineralization.
Using first order kinetic equations, and HPLC and GLC and radio-chemical methods, turnover rate constants (k-values) of between
0.18 and 0.32 day−1 and pool sizes of algal cell walls of 37 to 80 μg · g−1 wet mud were found, giving turnover rates of 7.7 to 25.6 μg · g−1 · day−1 of cell wall material. The turnover rates (k-values between 0.07 and 0.31 h−1) of acetate, the most important breakdown product, and its concentration gradients (between 5 and 30 μmol) and diffusion
coefficient (Ds = 2.2 × 10−6 cm2 · s−1) just in and above mud-water interface, was quantified. The diffusion of acetate, within the sediments, could not account
for the turnover rates observed.
Finally, from acetate flux data and from those on the rates of formation of carbon dioxide and methane, the output of carbon
and its cycling in Lake Vechten are discussed. 相似文献
17.
D. P. Kelly 《Archives of microbiology》1967,58(2):99-116
Summary Cultures of Thiobacillus neapolitanus strain C assimilate 14C-labelled acetate and aspartate. Both carbon atoms of acetate are incorporated, and 25% of the cell carbon can arise from acetate. Aspartate-14C contributes 4–5% of the cell carbon, and is found in pyrimidines and in protein as aspartate and its related amino acids. Acetate-14C contributes to lipid, glutamate, arginine, proline and leucine, but not to aspartate. Acetate assimilation by washed organisms requires carbon dioxide and energy from thiosulphate oxidation. Degradation of 14C-glutamic acid from acetate-14C-labelled bacteria; the accumulation of 14C-citrate in the presence of fluoroacetate and [14C] acetate; short-term kinetic experiments on acetate-14C turnover; and the demonstration of citrate synthesis by cell-free extracts all indicate glutamate synthesis from -ketoglutarate formed by reactions of the tricarboxylic acid cycle. The cycle is believed to be incomplete, probably not proceeding further than -ketoglutarate, and functions as a glutamate-synthesising system, using oxaloacetate derived solely from carbon dioxide fixation. Malate synthase (and the glyoxylate cycle) appear to be insignificant in the metabolism, but extracts did form citramalate from acetate and pyruvate. 相似文献
18.
Biosynthesis of glycosoaminoglycans by microsomal preparations from cultured mastocytoma cells 总被引:3,自引:2,他引:1
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Neoplastic mast cells of mice (including long-established and newly derived lines) were grown in large-volume suspension cultures to provide enough cells for preparation of microsomal fractions. Microsomal preparations from P815Y and P815S cells synthesized 14C-labelled glycosaminoglycan when incubated with UDP-[14C]glucuronic acid and UDP-N-acetylgalactosamine. No significant amount of 14C-labelled glycosaminoglycan was formed when UDP-N-acetylglucosamine was substituted for the UDP-N-acetylgalactosamine. Microsomal preparations from X163 cells synthesized 14C-labelled glycosaminoglycan when incubated with UDP-[14C]glucuronic acid and either UDP-N-acetylgalactosamine or UDP-N-acetylglucosamine. The 14C-labelled glycosaminoglycan formed in the presence of UDP-N-acetylgalactosamine was degradable by testicular hyaluronidase, indicating that it was chondroitin-like. The 14C-labelled glycosaminoglycan formed in the presence of UDP-N-acetylglucosamine was not degradable by testicular hyaluronidase. Microsomal preparations from P815S cells were tested for sulphating activity by incubation with adenosine 3′-phosphate 5′-sulphatophosphate, as well as UDP-[14C]glucuronic acid, and UDP-N-acetylgalactosamine. The resulting newly synthesized polysaccharide was shown by chondroitinase ABC digestion to be 70% chondroitin 4-sulphate and 30% chondroitin. The molecular size of this newly synthesized glycosaminoglycan was determined by gel filtration to be larger than 40000 mol.wt. In general, the glycosaminoglycan-synthesizing ability of the microsomal preparations appeared to reflect glycosaminoglycan synthesis by the intact cells. 相似文献
19.
Aims: In this article, a quantitative real‐time PCR assay for detection and enumeration of the spoilage yeast Dekkera anomala in beer, cola, apple cider, and brewing wort is presented as an improvement upon existing detection methods, which are very time‐consuming and not always accurate. Methods and Results: Primers were designed to exclude other organisms common in these beverages, and the assay was linear over 6 log units of cell concentrations. The addition of large amounts of non‐target yeast DNA did not affect the efficiency of this assay. A standard curve of known DNA was established by plotting the Ct values obtained from the QPCR against the log of plate counts on yeast peptone dextrose medium and unknowns showed exceptional correlation when tested against this standard curve. The assay was found to detect D. anomala at levels of 10–14 CFU ml?1 in either cola or beer and at levels of 9·4–25·0 CFU ml?1 in apple cider. The assay was also used to follow the growth of D. anomala in brewing wort. Conclusions: The results indicate that real‐time PCR is an effective tool for rapid, accurate detection and quantitation of D. anomala in beer, cola and apple cider. Significance and Impact of the Study: This method gives a faster and more efficient technique to screen beer, cola, and cider samples and reduce spoilage by D. anomala. Faster screening may allow for significant reduction in economic loss because of reduced spoilage. 相似文献
20.
Uptake, translocation and metabolism of 14C-labelled 4-amino-3,5,6-trichloropicolinic acid (picloram) and 2,4-dichlorophenoxyacetic acid (2,4-D) in seedlings of wheat (Triticum aestivum L.) were studied. The uptake of the herbicides through the upper surface of the first leaf was slow but was almost complete after nine days. Picloram was absorbed faster than 2,4-D. Picloram was also translocated into the stem and the untreated leaves to a greater extent than 2,4-D. Only small fractions of the activity were recovered from the roots and from the nutrient solution. Picloram and 2,4-D formed water-soluble conjugates in the tissues. These conjugates were very labile and hydrolyzed under release of the unchanged herbicides. The isotope from 2,4-D was also incorporated in an insoluble fraction, containing cell walls and proteins. Also from this fraction biologically active 2,4-D could be released by hydrolysis. The formation of the complexes was partly prevented by cycloheximide. It is suggested that herbicide detoxification through complex formation is of importance for the relatively low sensitivity of wheat to auxin herbicides. 相似文献