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1.
Microascus was associated with Aspergillus repens in a left maxillary sinus. Tissue contained septale filaments of two types, conidia, ostiolate perithecia containing ascospores corresponding to Microascus cinereus which was identified by culture. The abundance of sexual fructifications in the tissue indicates that pathogenicity is due to Microascus cinereus. 相似文献
2.
Ursula Meindl Doris Wittmann-Pinegger Oswald Kiermayer 《Plant Systematics and Evolution》1989,164(1-4):197-208
Cells ofMicrasterias denticulata
Bréb. were kept in nutrient solution of high osmolality (salt stress) for four weeks. In a special cell multiplication test it was established that cell division is gradually inhibited at increasing salt concentrations and totally arrested at the highest concentration (26 mosm/kg). Recovery studies proved that even cells from the highest concentration range start dividing immediately after being placed in aqua bidest. thus indicating the full reversibility of the inhibiting effect. — Cells of the highest concentration range show marked ultrastructural changes. Besides an enormous accumulation of starch and oil bodies and a condensed appearance of the ground plasma, a reduction of mitochondria, ER and the Golgi-system is found. The most striking effect occurs on the vacuolar system which appears extremely reduced and condensed. The cell wall is thickened by the formation of an additional cell wall layer with a spongy electron microscopical appearance. Through the cell wall many droplets of a probably fat-like substance are excreted. — In summary, salt stress induces growth-inhibited akinete cells in the sense ofFritsch; these can be reactivated by decreasing the salt concentration. The salt-induced akinete state seems to be an ecological adaption to unfavourable conditions rather than a degeneration of the cells.Dedicated to Prof. DrLothar Geitler on the occasion of his 90th birthday.23. 12. 1988 相似文献
3.
Two divergent populations of T. repens cv. Haifa developed from two generations of recurrent selection for shoot chloride concentration, were grown in the greenhouse at 0 and 40 mol m–3 NaCl. Over two harvest cycles at 40 mol m–3 NaCl, the population selected for a low concentration of chloride in the shoot maintained a significantly lower chloride and sodium concentration compared with those plants selected for a high shoot chloride concentration. The distribution of chloride in the shoots was further examined in a subsample of plants from both populations. In all plants, concentrations of chloride were lower in the expanding and fully expanded leaves than in the older leaf tissue or petioles.While there were no significant differences in the photosynthetic rates between lines, shoot yields and relative leaf expansion rates were higher in the low chloride population. Plant death was greater in plants selected for high shoot chloride. These results suggest that selections based on measurements of low shoot chloride concentrations may be successful in developing a cultivar of T. repens with improved salt tolerance. 相似文献
4.
5.
Effects of polyethylene glycol (PEG)-induced water stress on the activities of total leaf superoxide dismutase (SOD) and chloroplast
SOD (including thylakoid-bound SOD and stroma SOD) are described in white clover (Trifolium repens L.) grown in solution culture from rooted cuttings. Both leaf SOD and chloroplast SOD activities were markedly enhanced with
increasing concentration of PEG stress, generating osmotic potentials around the roots 0, −0.5, −1.0, −1.5 MPa. The effects
increased with time up to 72 h. Chloroplast Fe-containing SOD represented about 30% of the total leaf SOD activity in the
control plants and a significant increase in chloroplast SOD activity was found during the stress period. This accounted for
about 35.5–71.1% of the total leaf SOD activity. The proportion of chloroplast SOD in total leaf SOD not only increased with
the decreasing of osmotic potential, but also increased with incubation time. Furthermore, the increase in thylakoid-bound
SOD activity was much higher than that of stroma SOD in chloroplast of plants under water stress. The enhanced chloroplastic
SOD activity, especially thylakoid-bound SOD activity, demonstrated in Trifolium repens suggests that Fe-SOD located in chloroplasts play a more important role than cytosolic Cu/Zn-containing SODs in scavenging
O2
−. 相似文献
6.
The Casparian strip in the endodermis of vascular plant roots appears to play an important role in preventing the influx of salts into the stele through the apoplast under salt stress. The effects of salinity on the development and morphology of the Casparian strip in primary roots of maize (Zea mays L.) were studied. Compared to the controls, the strip matured closer to the root tip with increase in the ambient concentration of NaCl. During growth in 200 mM NaCl, the number and the length of the endodermal cells in the region between the root tip and the lowest position of the endodermal strip decreased, as did the apparent rate of production of cells in single files of endodermal cells (the rate of cell formation being equal to the rate at which cells are lost from the meristem). The estimated time required for an individual cell to complete the formation of the strip after generation of the cell in the presence of 200 mM NaCl was not very different from that required in controls. Thus, salinity did not substantially affect the actual process of formation of the strip in individual cells. The radial width of the Casparian strip, a morphological parameter that should be related to the effectiveness of the strip as a barrier, increased in the presence of 200 mM NaCl. The mean width of the lignified region was 0.92 m in distilled water and 1.33 m in 200 mM NaCl at the lowest position of the strip. The mean width of the strip relative to that of the radial wall at this position was significantly greater after growth in the presence of 200 mM NaCl than in the controls, namely, 20.5% in distilled water and 33.9% in 200 mM NaCl. These observations suggest that the function of the strip is enhanced under salt stress. 相似文献
7.
A. R. Kayumov N. P. Balaban A. M. Mardanova S. V. Kostrov M. R. Sharipova 《Microbiology》2006,75(5):557-562
The biosynthesis of the subtilisin-like serine proteinase of Bacillus intermedius 3–19 by the recombinant strain Bacillus subtilis AJ73(pCS9) was found to be enhanced under salt stress conditions (growth in a medium containing 1 MNaCl and 0.25 M sodium citrate). In a recombinant strain of B. subtilis deficient in the regulatory proteins DegS and DegU, which control the synthesis of degradative enzymes, the expression of the proteinase gene was inhibited. In contrast, in the strain B. subtilis degU32(Hy), which provides for the overproduction of proteins positively regulated by the DegS-DegU system, the biosynthesis of the subtilisin-like proteinase of B. intermedius 3–19 increased by 6–10 fold. These data suggest that the DegS-DegU system is involved in the positive regulation of the expression of the subtilisin-like B. intermedius proteinase gene in recombinant B. subtilis strains. 相似文献
8.
Summary Humidity, at the young nodes of white clover stolones, varied by enclosing nodes in the atmosphere above a range of saturated solutions, inhibited root initiation at 85% RH or less. The threshold humidity for root initiation increased to about 93% on young nodes subject to moisture stress or old nodes on well watered plants in which root initiation had been previously suppressed by low humidity.Roots at old nodes and at the three youngest on stolons were either subject to moisture stress or adequately watered. Growth of young roots and N2-fixation were more adversely affected by the direct effects of drought than by subjecting old roots to drought. Although old roots under stress affected new root growth and N2-fixation, length of roots and lateral root number were little affected. By contrast stolon growth was affected more by stress to old roots than to young nodes, although after 6 weeks the contribution made by young roots to stolon growth was almost as high as old roots.The data suggest that deep roots at old nodes will allow clover stolons to grow during drought due to the high acropetal movement of water but initiation of roots and functioning of young roots at the soil surface will be adversely affected, with possible implications on the persistence of clover. 相似文献
9.
Differential accumulation of S-adenosylmethionine synthetase transcripts in response to salt stress 总被引:4,自引:0,他引:4
NaCl stress causes the accumulation of several mRNAs in tomato seedlings. An upregulated cDNA clone, SAM1, was found to encode a S-adenosyl-L-methionine synthetase enzyme (AdoMet synthetase). Expression of the cDNA SAM1 in a yeast mutant lacking functional SAM genes resulted in high AdoMet synthetase activity and AdoMet accumulation. We show that tomato plants contain at least four SAM isogenes. Clones corresponding to isogenes SAM2 and SAM3 have also been isolated and sequenced. they encode predicted polypeptides 95% and 92% identical, respectively, to the SAM1-encoded AdoMet Synthetase. RNA hybridization analysis showed a differential response of SAM genes to salt and other stress treatments. SAM1 and SAM3 mRNAs accumulated in the root in response to NaCl, mannitol or ABA treatments. SAM1 mRNA accumulated also in leaf tissue. These increases of mRNA level were apparent as soon as 8 h after the initiation of the salt treatment and were maintained for at least 3 days. A possible role for AdoMet synthetases in the adaptation to salt stress is discussed. 相似文献
10.
【背景】青海省特殊生境孕育了特殊微生物资源。【目的】探究适合生活于高原生境的芽胞杆菌菌源。【方法】采用平板对峙法、显色法对萎缩芽胞杆菌(Bacillus atrophaeus) CKL1的拮抗、产吲哚乙酸活性进行测定,并检测耐低温、耐盐性及菌株对盐胁迫下燕麦品种(Avena sativa)“青燕1号”种子萌发、幼苗生长效应及叶绿素、脯氨酸、丙二醛的含量变化,利用二代测序技术对菌株进行基因组测序并分析相关功能基因。【结果】菌株CKL1对禾谷镰孢菌(Fusarium graminearum)、锐顶镰孢菌(Fusarium acuminatum)表现出显著的拮抗活性(抑菌圈直径>15 mm);与Salkowski比色液反应变红,能在NaCl浓度为13%的LB培养基及4℃低温下生长,表现出一定的产吲哚乙酸、耐盐及耐低温活性;盐胁迫下,菌株CKL1对“青燕1号”种子萌发及幼苗生长具有显著促进作用,叶绿素及脯氨酸含量显著增加,丙二醛含量下降,增强了燕麦的抗盐性。菌株CKL1基因组全长为14 281 280 bp,与GO功能数据库比对注释到3 303个功能基因;基因组编码与脂肽类化合物itur... 相似文献
11.
Synechococcus PCC 6301 synthesized sucrose as a compatible solute following hyperosmotic shock induced by NaCl. Initial rates of photosynthetic 14C incorporation were reduced following salt shock. Photosynthetic rates were comparable in cells enriched for glycogen (by growth in NO
3
-
-deficient medium) and cells grown in NO
3
-
-sufficient medium in the absence of osmotic shock. Incorporation of 14C was predominantly into the NaOH fraction and the residual acidic fraction in cells grown in NO
3
-
-sufficient medium, whereas incorporation was predominantly into the residual acidic fraction in cells grown in NO
3
-
-deficient medium. Following salt stress, 14C incorporation was initially into the ethanol-soluble fraction and the majority of tracer was recovered in sucrose. Carbon-14 was detected in sucrose in cells which had been enriched for [14C]glycogen prior to salt stress, inferring that glycogen can act as a carbon source for sucrose synthesis following salt stress. Changes in the specific activity of sucrose are consistent with an initial synthesis of sucrose from glycogen followed by synthesis of sucrose using newly fixed carbon, in response to salt stress.This work was supported by the Agricultural and Food Research Council. 相似文献
12.
Myung Hoon Song Ju-young Nah Yeon Soo Han Dong Min Han Keon-Sang Chae 《Biotechnology letters》2001,23(9):689-691
Addition of KCl to medium at 0.1 M or higher promoted the formation of conidial heads in Aspergillus oryzae. When higher concentrations of KCl were added, a larger number of conidial heads were formed. NaCl and MgCl2 were slightly less effective than KCl. The effect of salt on the formation of conidial heads on a minimal medium was as high as on a potato/dextrose medium but slightly higher than that on a complex medium when 1 M KCl was added. 相似文献
13.
【背景】盐胁迫环境严重影响大豆幼苗生长,内生菌可提高作物的抗逆性。【目的】探究接种内生枯草芽孢杆菌127和解蛋白芽孢杆菌133对盐胁迫下大豆幼苗体内超氧化物歧化酶(superoxide dismutase,SOD)和过氧化物酶(peroxidase,POD)活性的影响。【方法】以“徐豆20”为实验材料,采用盆栽实验法,设置对照组、盐胁迫组和盐胁迫接菌组,在人工气候培养条件下,用不同NaCl浓度(50、100、150、200、250和300 mmol/L)处理大豆幼苗,并接种不同OD600值(OD0.33、OD0.50和OD0.75)的菌悬液。【结果】培养14 d,接种枯草芽孢杆菌127的菌悬液OD0.33和OD0.75分别在盐浓度300 mmol/L和100 mmol/L时,SOD活性均为1.04 U/g-FW;接种解蛋白芽孢杆菌133的菌悬液OD0.50在盐浓度300 mmol/L胁迫下POD活性最高为7 820 U/(g·min),对大豆幼苗修复效果较显著。培养28 d,接种枯草芽孢杆菌127的菌悬液OD0.50,在150 mmol/L时SOD活性最高(0.88 U/g-FW);接... 相似文献
14.
Scavenger Enzyme Activities in Subcellular Fractions of White Clover (Trifolium repens L.) under PEG-induced Water Stress 总被引:1,自引:0,他引:1
Scavenger enzyme activities in subcellular fractions under polyethylene glycol (PEG)-induced water stress in white clover
(Trifolium repens L.) were studied. Water stress decreased ascorbic acid (AA) content and catalase (CAT) activity and increased the contents
of hydrogen peroxide (H2O2), thiobarbituric acid reactive substances (TBARS) (measure of lipid peroxidation), and activities of superoxide dismutase
(SOD), its various isozymes, ascorbate peroxidase (APOX), and glutathione reductase (GR) in cellular cytosol, chloroplasts,
mitochondria, and peroxisomes of Trifolium repens leaves. In both the PEG-treated plants and the control, chloroplastic fractions showed the highest total SOD, APOX, and GR
activities, followed by mitochondrial fractions in the case of total SOD and GR activities, whereas cytosolic fractions had
the second greatest APOX activity. However, CAT activity was the highest in peroxisomes, followed by the cytosol, mitochondria,
and chloroplasts in decreasing order. Although Mn-SOD activity was highest in mitochondrial fractions, residual activity was
also observed in cytosolic fractions. Cu/Zn-SOD and Fe-SOD were observed in all subcellular fractions; however, the activities
were the highest in chloroplastic fractions for both isoforms. Total Cu/Zn-SOD activity, the sum of activities observed in
all fractions, was higher than other SOD isoforms. These results suggest that cytosolic and chloroplastic APOX, chloroplastic
and mitochondrial GR, mitochondrial Mn-SOD, cytosolic and chloroplastic Cu/Zn-SOD, and chloroplastic Fe-SOD are the major
scavenger enzymes, whereas cellular CAT may play a minor role in scavenging of O2− and H2O2 produced under PEG-induced water stress in Trifolium repens. 相似文献
15.
da Silva Bahia Maria Cleide F. Vieira Ricardo P. Mulloy Barbara Hartmann Rudolf Bergter Eliana Barreto 《Mycopathologia》1997,137(1):17-25
A study was made of polysaccharides and glycosphingolipids isolated from Aspergillus fumigatus grown in media supplemented with human serum from healthy donors. Fractionation of Cetavlon-precipitated polysaccharides on Sephacryl S-400 gave rise to an excluded fraction (Fraction I) with molecular weight of >400 kDa and an included peak (Fraction II) with an average molecular weight of 30–80 kDa. Fraction I comprises about 5% of total polysaccharide and was identified as a glycogen-like molecule. Its structure was deduced from methylation data, treatment with amyloglucosidase, a red-brown coloration produced with an iodine solution and by 1H and 13C-NMR spectroscopy. It was previously suggested that higher amounts of glycogen-like polysaccharide (20%) were present in A. fumigatus grown in serum-free medium. Fraction II was identified as a galactomannan and was the main polysaccharide of A. fumigatus grown in serum-supplemented medium. Its structure was elucidated mainly by 13C-NMR spectroscopy combined with partial acetolysis and methylation analysis. The 13C-NMR spectrum of the galactomannan showed a much greater complexity in the -d-galf and -d-manp C-1 regions, than was evident for galactomannan from serum-free cultures previously described, reflecting differences in the glycosylation pattern, stimulated in serum-supplemented medium.No differences in A. fumigatus glycosphingolipid could be detected between serum-containing and serum-free growth conditions.Our results demonstrate that the change in polysaccharide structure is a more specific response to the altered growth conditions and not merely a symptom of more general changes.This revised version was published online in October 2005 with corrections to the Cover Date. 相似文献
16.
Effect of salt stress on fatty acid alterations in some strains of Dipodascopsis and Dipodascus spp.
J. Šajbidor M. Lamačka E. Breirerová A. Chrastina P. Pokreisz M. Čertík 《World journal of microbiology & biotechnology》1994,10(2):184-186
The effect of salt stress (8% w/v NaCl) on fatty acid composition of eight strains of Dipodascus and Dipodascopsis spp. varied from being of slight influence only (Dipodascopsis uninucleata), to decreasing the content of 18:2 (D. reesii, D. tetrasperma and D. australiensis) and to decreasing both 18:1 and 18:2 (D. tothii and D. aggregatus) with a concomitant rise of 14:1 and 16:1. With the exception of D. aggregatus, NaCl inhibited lipid accumulation in all strains. Only trace amounts of fatty acids over C18 in chain length were found.J. ajbidor, M. Lamaka, A. Chrastina and P. Pokreisz are with the Department of Biochemical Technology, Slovak Technical University, Radlinskeho 9, 812 37, Bratislava, Slovak Republic; E. Breirerová is with the Institute of Chemistry, Slovak Academy of Science, Dúbravská cesta 9, Slovak Republic. M. Certík is with the Research Institute of Gerontology, Zámocká ul, P.O. Box 25, 901 01 Malacky, Slovak Republic. 相似文献
17.
Peroxidase mediated hydrogen peroxide production in barley roots grown under stress conditions 总被引:5,自引:0,他引:5
All applied metals (Co, Al, Cu, Cd) and NaCl inhibited barley root growth. No root growth inhibition was caused by drought exposure, in contrast to cold treatment. 0.01 mM H2O2 stimulated root growth and GA application did not affect root growth at all. Other activators and inhibitors of H2O2 production (SHAM, DTT, 10 mM H2O2, 2,4-D) inhibited root growth. Loss of cell viability was most significant after Al treatment, followed by Cd and Cu, but no cell death was induced by Co. Drought led to slight increase in Evans blue uptake, whereas neither NaCl nor cold influenced this parameter. DTT treatment caused slight increase in Evans blue uptake and significant increases were detected after 2,4-D and 10 mM H2O2 treatment, but were not induced by others stressors. Metal exposure increased guaiacol-POD activity, which was correlated with oxidation of NADH and production of H2O2. Exposure to drought caused a minor change in NADH oxidation, but neither H2O2 production nor guaiacol-POD activity was increased. Cold and NaCl application decreased all monitored activities. Increase in NADH oxidation and guaiacol-POD activity was caused by 10 mM H2O2 and 0.01 mM 2,4-D treatment, which also caused enhancement of H2O2 production. Slight inhibition of all activities was caused by 0.01 mM H2O2, GA, DTT; more pronounced inhibition was detected after SHAM treatment. The role of H2O2 production mediated by POD activity in relation to root growth and cell viability under exposure to some abiotic stress factors is discussed. 相似文献
18.
József Téren János Varga Zsuzsanna Hamari Edit Rinyu Ferenc Kevei 《Mycopathologia》1996,134(3):171-176
One hundred and fifty-seven strains belonging to Aspergillus section Nigri were tested for ochratoxin A production using three different methods: a relatively new immunochemical method based on an enzyme-linked immunosorbent assay (ELISA), thin-layer chromatography (TLC) and high-performance liquid chromatography (HPLC). The monoclonal antibody-based ELISA technique was successfully used to screen for low levels of ochratoxin A in the black Aspergilli without concentrating the culture filtrates. The results were confirmed by TLC and HPLC analysis and chemical derivatization. These latter methods required concentrated filtrates. Ochratoxin A was detected in the culture filtrates of five of the 12 A. carbonarius strains, none of the 45 A.japonicus strains and three of the 100 isolates in the A. niger aggregate (A. foetidus, A. awamori and A. niger).Abbreviations ELISA
enzyme-linked immunosorbent assay
- HPLC
high-performance liquid chromatography
- OA
ochratoxin A
- TLC
thin-layer chromatography 相似文献
19.
20.
Spermine accumulation under salt stress 总被引:11,自引:0,他引:11
Polyamines have long been recognized to be linked to stress situations, and it is generally accepted that they have protective characteristics. However, little is known about their physiological relevance in plants subjected to long-term salt stress. In order to precise their importance, two rice (Oryza sativa) cultivars differing in their salt tolerance were salinized for 7, 14 and 21 days. The activities of some of the enzymes involved in polyamine metabolism, free polyamines and proline contents were evaluated. Arginine decarboxylase and S-adenosyl-L-methionine decarboxylase activities were reduced in both cultivars as a consequence of salt treatment. However, spermidine synthase activity was reduced in the salt tolerant cultivar (var Giza) but not in the salt sensitive (var El Paso), while no polyamine oxidase activity was detected. During the salinization period, putrescine and spermidine levels decreased in both cultivars, although less dramatically in Giza. Simultaneously, spermine accumulations occur in both varieties, while proline accumulation was major in the sensitive one. However, spermine accumulation induced by treatment with spermidine synthase inhibitor cyclohexylamine, determined no reduction in leaf injury associated with salt stress in both cultivars. The data presented suggest that spermine accumulation is not a salt tolerance trait. 相似文献