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1.
Thirty one strains of Rhizobium leguminosarum biovar trifolii isolated from the North and South American continents, New Guinea, USSR, Turkey and Australia, nodulated P. andersonii ineffectively when grown in plant growth tubes and in Leonard jars. Nodules were slow to form, sometimes taking over 100 days. Reisolates of R. leguminosarum biovar trifolii from P. andersonii nodulated Trifolium repens and their identity was confirmed using serological techniques. Dual occupation of nodules by Rhizobium and Bradyrhizobium in P. andersonii is reported. The reduced effectiveness of the Bradyrhizobium symbiosis depended on the relative numbers of Rhizobium occupants in this dual system. R. leguminosarum biovar trifolii and Bradyrhizobium strains from Parasponia were able to co-exist in nodules on P. andersonii and maintain similar populations in the rhizosphere and on culture media. Bradyrhizobium strains, separated from R. leguminosarum biovar trifolii, were able to initiate and form nodule-like structures on T. repens. Bradyrhizobium bacteria were identified as the sole occupants of the cells of the nodule-like structures on Trifolium repens using an immunogold labelling technique applied to ultrathin sectins. The re-isolates of Bradyrhizobium obtained from these nodule-like structures on T. repens were able to effectively nodulate P. andersonii.  相似文献   

2.
The effect of the placement of inoculum of Fusarium oxysporum at two soil depths, and the sequences of inoculations with Meloidogyne arenaria and Fusarium oxysporum on root growth and development of root disease in Trifolium subterraneum L. (subterranean clover) were investigated. The timing of infection and the proximity of root tips of the host root system to infection by M. arenaria and F. oxysporum appeared to be the major determining factors of root growth and of disease development in plants exposed to the pathogens. Immediate contact of roots with F. oxysporum (where the fungus was placed at seed level of 10 mm depth) appeared to result in more severe effects on roots in the presence of the nematode than later infection by the fungus placed at 30 mm depth. The production of galls by the nematode and early infection by F. oxysporum at 10 mm depth resulted in a severe inhibition of root growth, particularly of the lateral roots. But no such growth inhibition was evident when F. oxysporum and M. arenaria were introduced together at the lower depth of 30 mm. The lowest density of M. arenaria inoculum was sufficient to cause severe root rot if F. oxysporum was present at the host seed level. With the fungus at 30 mm depth, however, the expression of root rot appeared to be influenced by the inoculum level of the nematode. In sequential inoculation with F. oxysporum or M. arenaria, the organism added 2 weeks later had little or no effect on root development. The first organism (M. arenaria or F. oxysporum) to infect the germinated seedlings was the main cause of root growth inhibition. The organism that came into contact with the roots 2 weeks later had little or no effect on the roots. Concurrent infection by F. oxysporum and M. arenaria resulted in less M. arenaria gall production on the tap root system than those added with the nematode alone or in advance of the fungus.  相似文献   

3.
The correlations between nitric oxide products (NO x ) and the angiotensin-converting enzyme (ACE) activity and malondialdehyde (MDA) were studied in the blood serum of patients with thoracic wounds (the test group) 1, 3, 7, and 14 days after the injury. The severity of a patient's state scored from 8 to 15 on the APACHE II scale. The control group comprised 20 blood donors. One day after wounding, NO x , MDA, and ACE activity significantly increased. Subsequently, NO x and ACE activity decreased, whereas MDA increased. A significant negative correlation was found between NO x and MDA, and a significant positive correlation, between NO x and ACE activity. The correlations observed in the control group were undetectable in the patients one day after wounding but were restored on the third day. Thus, thoracic injury was accompanied by an increase in NO x and MDA, which determine the severity of oxidative stress. The positive correlation between NO x and ACE activity in the control and test groups reflects their concerted action in regulating the physiological functions and metabolism.  相似文献   

4.
The white-rot fungi Trametes versicolor PRL 572, Trametes versicolor MUCL 28407, Pleurotus ostreatus MUCL 29527, Pleurotus sajor-caju MUCL 29757 and Phanerochaete chrysosporium DSM 1556 were investigated for their ability to degrade the polycyclic aromatic hydrocarbons (PAH) anthracene, benz[a]anthracene and dibenz[a,h]anthracene in soil. The fungi were grown on wheat straw and mixed with artificially contaminated soil. The results of this study show that, in a heterogeneous soil environment, the fungi have different abilities to degrade PAH, with Trametes showing little or no accumulation of dead-end metabolites and Phanerochaete and Pleurotus showing almost complete conversion of anthracene to 9,10-anthracenedione. In contrast to earlier studies, Phanerochaete showed the ability to degrade the accumulated 9,10-anthracenedione while Pleurotus did not. This proves that, in a heterogeneous soil system, the PAH degradation pattern for white-rot fungi can be quite different from that in a controlled liquid system. Received: 20 March 1996 / Received revision: 2 July 1996 / Accepted: 8 July 1996  相似文献   

5.
By the example of fetuin and a blood-group-specific mucin from porcine stomach, we showed that, under conditions of reductive degradation of glycoproteins with LiBH4-LiOH in 70% aqueoustert-butyl alcohol, the reduction and cleavage of amide bonds occur much faster than the simultaneous β-elimination of carbohydrate chainsO-linked with Ser and Thr residues of the peptide chain. The major degradation products containing theO-linked glycans are theO-glycosylated derivatives of 2-aminopropane-1,3-diol and 2-aminobutane-1,3-diol (the products of reduction of glycosylated Ser and Thr) and the glycopeptides containing 2–4 amino acid residues with reducedC-terminal amino acid. Seventeen homogeneousO-glycopeptides were isolated from the fetuin degradation products by ion-exchange and reversed-phase HPLC. Their structures were determined by MALDI-TOF mass spectrometry and by analyses for amino acids, amino alcohols, and carbohydrates. The application of the reaction for characterization ofO-glycans and localization ofO-glycosylation sites inO- andN,O-glycoproteins is discussed. Deceased.  相似文献   

6.

Background  

Spinal muscular atrophy (SMA) is an autosomal recessive disorder that affects the motoneurons of the spinal anterior horn, resulting in hypotonia and muscle weakness. The disease is caused by deletion or mutation in the telomeric copy of SMN gene (SMN1) and clinical severity is in part determined by the copy number of the centromeric copy of the SMN gene (SMN2). The SMN2 mRNA lacks exon 7, resulting in a production of lower amounts of the full-length SMN protein. Knowledge of the molecular mechanism of diseases has led to the discovery of drugs capable of increasing SMN protein level through activation of SMN2 gene. One of these drugs is the valproic acid (VPA), a histone deacetylase inhibitor.  相似文献   

7.
Following UV mutagenesis of protonemal tissue of the moss Ceratodon purpureus we have isolated different aphototropic mutant lines that can be divided into two distinct classes. One class, represented by the line ptr1, shows characteristic features of phytochrome chromophore deficiency. ptrl shows negligible photoreversibility (<5% of wild type), whereas immunoblots show normal apoprotein levels. The aphototropic phenotype could be partially restored with biliverdin, a precursor of the phytochrome chromophore. It was found that, whereas in wild type formation of Pfr leads to suppression of gravitropism, there is no such suppression ptrl. In addition, ptr1 shows lower chlorophyll levels than the wild type. These findings indicate that, as expected for a chromophore-deficient mutant, multiple phytochrome effects are lost. The other class of mutants, represented by the line ptr103, shows more specific effects. In this mutant, only phototropism is affected. Suppression of gravitropism, the content of chlorophyll and photoreversibility of phytochrome were similar to those of the wild type.  相似文献   

8.
Summary Aspergillus niger and Trichoderma viride strains were used together as a fungal activator in the presence or absence of farmyard manure (FM) for composting of bagasse enriched with rock phosphate. Quality of the composts produced was compared with that obtained from non-inoculated bagasse. The composts were evaluated as organic phosphatic fertilizers, for broad bean plants. The results showed that composting of bagasse without microbial inoculation or FM addition was not complete after 105 days of fermentation. An excellent decomposition in a relatively short time however was obtained with the use of A. niger and T. viride as inoculant agents with or without FM. The inoculation with A. niger + T. viridewith or without FM, also represented the most suitable conditions for phosphate solubilization. Acidic conditions (pH 4–5) at the end of the experiment were obtained in all piles receiving Aspergillus niger and there was a correlation between the amounts of soluble phosphorus and the reduction in pH values in the compost piles. There were no phosphate-dissolving fungi present in any composted piles except those treated with Aspergillus niger and Trichoderma viride. The number of phosphate-dissolving bacteria increased only in the treatments that were treated with FM. The non-fertilized sandy soil and the non-inoculated bagasse compost did not provide broad bean plants with phosphorus while the composts produced by inoculation with A. niger + T. viride provided the plants with the highest amounts of phosphorus.  相似文献   

9.
Experimental infection of white mouse with chrysosporium and paecilomyces   总被引:1,自引:0,他引:1  
SPF white mice were inoculated intraperitoneally with 5 strains of saprophytic fungi of the mycelial genera Chrysosporium (C. keratinophilum, C. tropicutn) and Paecilomyces (P. lilacinus, P. marquandii, P. victoriae). The fungi caused granulomatous lesions in the peritoneal cavity and they were recultured (except P. lilacinus and P. marquandii) two months after inoculation. Spores, short hyphae and budding cells of all the fungi were observed in the granulomas stained by periodic-acid Schiff (PAS) and methenamine-silver nitrate (Grocott) techniques.  相似文献   

10.
Summary The gametic algebraG is constructed for a random mating population of 2r-ploid individuals which differ in a single locus with the allelesA anda. It is assumed that every kind of segregation between chromosome- and chromatid segregation occurs with a given probability. This algebraG is a convex combination of 2r+1 genetic algebras which have a common canonical basis. The train roots of these algebras are calculated and shown to be monotonically descending. The algebraG possesses a one-dimensional manifold of idempotents. With a generalization of Gonshor's theorem on the convergence of the sequence of plenary powers of an element of unit weight it is shown that for every initial gametic distribution the distribution in the following generations converges towards an equilibrium state whose coordinates are polynomials in the frequency of the alleleA in the initial generation.  相似文献   

11.
For this study, 21 isolates of fungi belonging to Rhizoctonia and Fusarium genera were isolated from the diseased faba bean plants, obtained from the different localities in Assiut governorate, showing root rot and wilt symptoms. The isolates proved to be pathogenic on Masr 1 faba bean cultivar under greenhouse conditions. F. oxysporum isolates caused wilt disease; however, the isolates of R. solani and other Fusarium species caused root rot. The virulence of isolates on the tested faba bean cultivar was different. The highly pathogenic isolates of these fungi were employed in this study. The effect of soil amendment with Planta Rich and Rich Composts (CMs) alone or in combination with seed coating by the antagonistic yeast Pichia guilliermondi before sowing on the severity of Rhizoctonia and Fusarium root rot and Fusarium wilt of faba bean was tested under greenhouse and field conditions. The tested isolates of yeast proved to be highly antagonistic to the pathogen in vitro. The test rates of CMs were equivalent to 2, 7, 10 and 14 ton/feddan in the greenhouse and 7 and 10 t/feddan in the field conditions. Uncomposted soil was used as a control. The results showed that the tested CMs have a suppressive effect on the severity of root rot and wilt diseases of faba bean under greenhouse and field conditions. The application of CMs (Planta Rich and Rich) alone at the rates equivalent to 2, 7, 10 and 14 t/feddan in greenhouse and 7 and 10 t/feddan in the field conditions to the soil infested with the tested pathogens reduced percentage of the tested diseases compared with uncomposted soil. Combined CMs treatments with yeast seed treatment increased the suppressive effect of CMs on the disease severity.  相似文献   

12.
The effect of copper sulphate on morphology and physiology of Lyngbya nigra has been studied. The growth was inhibited in all treatments (0.4 to 80.0 μM) of copper sulphate. There were no apparent morphological changes up to 0.8 μM and during the first two days of treatment even in the higher concentrations of copper sulphate. In concentrations above 0.8 μM the first symptom of toxicity was the formation of separation discs in large numbers. The trichomes contracted longitudinally and the cells became swollen and constricted at the cross walls. The cells also became yellowish due to loss of photosynthetic pigments. Finally, in 4 μM and above, vacuoles appeared in large number indicating the moribund state of the cells. Copper sulphate increased respiration at 2 μM, and optimum effect was observed in 8 μM after 96 h. Inhibition of photosynthesis was detectable in 0.8 μM, and 100% inhibition took place in 8 μM after 96 h. In higher concentrations the effect was immediate, and a conspicuous inhibition of photosynthesis could be observed within 10 min. The copper content of the alga increased with increased concentration of copper sulphate while potassium content decreased. With rise in outside concentrations of copper, there was a comparatively great increase of absorption in 2 and 4 μM, while further increases were gradually less. The observations indicate that changes in the physiological activity of the alga under treatment are closely interlinked with marked changes in morphology.  相似文献   

13.
Spectrophotometric titrations of slightly substituted carboxymethylamylose (CM-Amy) and diethylaminoethylamylose (DEAE-Amy) with iodine in the presence of iodide (I2/I?) were carried out as a function of iodide concentration, temperature, and polymeric charge. Binding isotherms for the polymer-I2/I? complex are reported in terms of an apparent binding constant (Ka) plotted versus degree of saturation of the complex (θ). The dependence of Ka upon polymeric charge is interpreted as evidence for the negatively charged character of the bound species. The cooperative nature of the binding process is evident in the positive slope of Ka vs (θ). Whereas the apparent binding constants and binding cooperativities for the derivatives are smaller than for the amylose-I2/I? complex, the binding enthalpies deduced from the temperature dependence of Ka at θ = 0.5 appear to be the same for amylose and CM-Amy. A viscometric titration of fully charged CM-Amy with I2/I?, conducted at dialysis equilibrium between the CM-Amy-I2/I? solution and the polymer-free solvent phase, disclosed a maximum in the plot of intrinsic viscosity ([η]) vs θ. The increase in [η] at small θ was interpreted as a reflection of polyelectrolyte expansion provoked by absorption of the negatively charged bound species; the subsequent decline in [η] is attributed to stabilization by I2/I? of compact helical sequences or to the formation at higher θ of intermolecular aggregates.  相似文献   

14.
Woodborers in the Agrilus genus (Coleoptera: Buprestidae) pose high invasiveness risk as indicated by the recent invasion and continental spread of emerald ash borer, and the associated threat to ash resources in North America. In that context, development of detection tools for potentially invasive Agrilus spp. is a research priority. Experiments carried out in 2013 in Slovakian beech and poplar forests evaluated the attraction of multiple Agrilus species to green and purple sticky prism traps baited with various lures [blank, cubeb oil, (Z)‐3‐hexenol]. The two most abundant species were Agrilus viridis L. in beech (Fagus spp.) forest (146 adults, >95% of which were females) and Agrilus convexicollis Redtenbacher in poplar (Populus spp.) forest (158 adults, two‐thirds of them males). The two species exhibited opposite responses to color: purple traps attracted 2–3× more adult A. viridis than green traps, whereas most (>95%) specimens of A. convexicollis were captured on green traps. Volatile baits did not influence captures of adults for either species. The introduction and establishment of A. viridis in North America is of particular concern owing to its feeding niche (primary pest that can attack healthy trees), large body size, and high level of polyphagy (>10 genera of host trees). Additional experiments conducted in beech forests in 2014 found purple prism traps more attractive to female A. viridis than green prism traps, especially those baited with cubeb oil. No analysis was conducted for males because of their low abundance. Female A. viridis flew earlier in 2013 than in 2014, but neither their body size nor fecundity varied between years. In both years, large females had more eggs in their abdomen than small females, and the number of eggs steadily declined over time, which suggests that female A. viridis are reproductively mature at emergence.  相似文献   

15.
The cross-reactions of rat kidney with P. mirabilis and E. coli, and of rat urinary bladder with P. mirabilis were established by precipitation, agglutination and immunofluorescence methods. One of the cross-reactive bacterial components was the lipopolysaccharide. Human erythrocytes of Blood-groups A, O and AB were agglutinated by antisera to P. mirabilis and E. coli. The role of antigenic relatedness in urinary tract infections is discussed.  相似文献   

16.
Summary The previously reported nucleotide sequence of the spoOA coding region of Bacillus subtilis suggested that the protein is initiated with either of two possible initiation codons, ATG and GTG, 84 base pairs apart. To determine which codon is utilized as an initiator in B. subtilis, we constructed a fusion gene in which the promoter and NH2-terminal region of the spoOA gene was connected to the chloramphenicol acetyltransferase gene (cat gene). After introduction of the plasmid carrying the spoOA-cat fusion gene into B. subtilis cells, the fusion protein was purified by affinity chromatography. The sequence of NH2-terminal amino acids of the fusion protein was determined and the result established that the GTG codon is utilized as an initiator in B. subtilis.Comparison of the amino acid sequences revealed a marked homology between the spoOA (NH2-terminal half) and spoOF proteins. A less striking but significant homology was also found between the spoOA (COOH-terminal half) and spoOB proteins. This suggests the presence of a common functional domain structure for these proteins that are supposed to play key regulatory roles in sporulation.  相似文献   

17.
The effect of inoculating seedlings of Eucalyptus grandis, Allocasuarina littoralis and Casuarina equisetifolia with two isolates of Pisolithus and two isolates of Scleroderma from under eucalypts was examined in a glasshouse trial. Ectomycorrhizas formed extensively on Eucalyptus (23–46% fine roots ectomycorrhizal) and Allocasuarina (18–51% fine roots ectomycorrhizal). On Casuarina, the fungi were either unable to colonize the rhizosphere (one isolate of Pisolithus), or sheathed roots, resembling ectomycorrhizas, formed on 1–2% of the fine roots. Colonization of roots by one isolate of Scleroderma resulted in the death of Casuarina seedlings. Inoculation with fungi increased shoot dry weight by up to a factor of 32 (Eucalyptus), 4 (Allocasuarina) and 3 (Casuarina). Ectomycorrhizas formed in associations with Eucalyptus and Allocasuarina had fully differentiated mantles and Hartig nets in which the host and fungal cells were linked by an extensive fibrillar matrix. Sheathed roots in Casuarina lacked a Hartig net, and the epidermis showed a hypersensitive reaction resulting in wall thickening and cell death. The sheaths are described as mantles since the density and arrangement of the hyphae in the sheaths was similar to that in mantles of the eucalypt ectomycorrhizas. The intercellular carbohydrate matrix was not produced in the Casuarina mantle in association with Pisolithus, hence the mantle was not cemented to the root. These structures differ from poorly compatible associations described previously for Pisolithus and Eucalyptus. The anatomical data indicate that ectomycorrhizal assessment based on surface morphological features may be misleading in ecological studies because compatible and incompatible associations may not be distinguishable.  相似文献   

18.
Summary Brassica napus and Brassica juncea were infected with a number of Agrobacterium tumefaciens strains. Tumourigenesis was very rapid and extremely efficient on B. juncea with all but one of the strains. Tumourigenesis on B. napus varied widely. It was very efficient with the nopaline strains, was reduced with the succinamopine strain A281 and was very weak with the octopine strains. The latter observation was confirmed with six different B. napus rapeseed cultivars. The selectivity was due to differences in the virulence of Ti plasmids with B. napus, rather than the tumourigenicity of the T-DNA or virulence of the chromosomal genes associated with the strains. An exception was strain LBA4404. The virulence of the octopine strains was increased by coinfection with more virulent disarmed strains and by induction with acetosyringone.  相似文献   

19.
Summary Purkinje fibers of the sheep heart were exposed to (a) 0.1mm dihydro-ouabain (DHO), followed by (b) 0.1mm DHO in Na-free solution or to (c) 1mm dinitrophenol (DNP). The degree of electrical decoupling was characterized in terms of the inside longitudinal resistancer i as measured with a 3-microelectrode voltage-clamp technique. Procedurea increasedr i by a factor of 3.7±1.1 (mean±sd),b by a factor of 9.8±2.2, whereas inc incomplete voltage control indicated nearly complete uncoupling. Intracellular calcium activity (aCa i ) was monitored with a microelectrode system. At control conditionsaCa i was below 0.1 m. The procedures listed above increasedaCa i to (a) 4±1.5 m, (b) 8±2 m, and (c) 36±12 m. The increase ofaCa i was in good correlation with the changes in core resistance. Effects on nexus ultrastructure, investigated with freeze-fracture techniques, are shown in histograms. At control conditions, the particle diameter distributed around a single peak (8.3±0.5 nm). Proceduresb andc induced a second population at 10.8 nm; increased decoupling reduced the control population in favor of the 10.8 nm population. Decoupling enlarged the width of the nexus gap by a factor of 1.6; again, the control population decreased in favor of a new population. In the decoupled state the height of the particle was smaller. Pits on the E-face displayed a more regular array and a nearly unchanged center-to-center spacing. Separation into several peaks was not possible due to scatter of the data.We interpret the findings to mean that elevatedaCa i induces a conformational change of the nexus subunits which corresponds to a transition from an open to a closed state. The conformational change can be formally described by a particle contraction which disrupts the continuity with the particle of the adjacent membrane. Purkinje fibers exposed to DNP for 1 hr showed thinned (7.7±0.5 mm) and elongated particles. We suggest that this is a secondary event and not a precursor of functional uncoupling.  相似文献   

20.
Conventional cross-linking of proteins involves the use of toxic chemicals. Here, cross-linking of gelatine and gelatine hydrolysates with tyrosinases from Botryosphaeria obtusa (BoT1 and BoT2), Agaricus bisporus (AbT) and from Verrucomicrobium spinosum (VsT) and with laccases from Trametes hirsuta (ThL) and T. versicolor (TvL) was demonstrated. Enzymatic oxidation of tyrosine residues was indicated by UV/VIS and fluorescence spectroscopy and further confirmed by oxygen consumption measurements. Using a model substrate (Tyr-Ala) dimerization was demonstrated by using RP-HPLC and LC-MS. Enzymatic cross-linking significantly increased the molecular weight of the soluble material up to the point of precipitation as demonstrated by both SDS-PAGE and size exclusion chromatography. The effect of cross-linking was further enhanced in the presence of phenolic molecules such as catechin.  相似文献   

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