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1.
Morphology, ultrastructure, and bacteriophage infection of the helical mycoplasma-like organism (Spiroplasma citri gen. nov., sp. nov.) cultured from "stubborn" disease of citrus 总被引:18,自引:15,他引:3
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The mycoplasma-like organism Spiroplasma citri gen. nov., sp. nov., isolated from citrus infected with "Stubborn" disease and carried in serial cultures in several media, was examined by dark-field microscopy and electron microscopy of negatively-stained and shadowed preparations and of sections. It grows as motile, helical filaments in liquid, but as nonmotile, nonhelical filaments and round bodies in agar cultures. Helicity and motility are lost in old broth cultures and upon addition of a variety of negative stains, fixatives, and other solutions. No organelles accounting for motility are present, but a layer of surface projections is present on the surface of the single, bounding membrane. The mycoplasma produces a tailed, type B bacteriophage which appear to attach to the outer layer. Helical filaments are preserved in ammonium molybdate, but not in sodium phosphotungstate, and by fixation in Formalin or glutaraldehyde made up in medium, but not by osmium nor by glutaraldehyde in cacodylate buffer. This mycoplasma appears similar to the noncultured helical microorganism in corn stunt-diseased tissues and is probably a representative of a new group of mycoplasmas which are in possession of surface projections, rotary motility, and bacteriophage infection. 相似文献
2.
Summary Electron microscopic examination ofCuscuta odorata, used for transmission trials, revealed mycoplasma-like organisms (MLO) as well as rhabdovirus-like particles, unknown toCuscuta. The virus infection is confined to certain phloem-parenchyma cells and a 1–2 cell thick layer of parenchyma cells with thickened walls surrounding the central cylinder. Virus particles, mostly bacilliform, could be detected mainly in the nucleus but also in the cytoplasm. They reach a length of 350–400 nm and a diameter of approximately 75 nm. Virus assembly takes place exclusively in the nucleus. Virus maturation occurs in membrane bound areas within the nucleus, which have no connection with the perinuclear space. Formation of nucleocapsids is always associated with a nuclear viroplasm. Envelopment of virus particles occurs in these membrane bound areas. Budding into the perinuclear space does not occur. Virus infection leads to degeneration and finally to death of the protoplast.Abbreviations cy
cytoplasm
- m
membrane stacks
- mt
mitochondria
- my
mycoplasma-like organisms
- nc
nucleocapsid
- ncp
nucleocapsid particles
- nf
nuclear filaments
- np
nucleoplasm
- nu
nucleus
- nvp
nuclear viroplasm
- oc
obliterated cells
- p
plastid
- pc
passage cells
- ph
phloem
- ps
perinuclear space
- spc
strand of parenchymatous cells
- v
virus particle
- x
xylem 相似文献
3.
Summary The presence of mycoplasma has been demonstrated in the phloem of leaves of white clover (Trifolium repens L.) affected by clover dwarf. Mycoplasma-like bodies were found both in parenchyma and companion cells and in sieve elements.In young parenchyma and companion cells mycoplasma-like bodies appeared as round or oval particles with high ribosomal content, delimited by a ribosome-bearing membrane. Their diameter ranged between 50 and 400 nm. In mature sieve elements they were larger, more pleomorphic, and showed a central clear area containing presumed DNA filaments. Budding and dividing forms were sometimes seen among them.The main alterations found in the infected cells were: increased ribosome content, dilation of the perinuclear space, degeneration of mitochondria and chloroplasts, and cytoplasmic vacuolation. Many cells appeared completely disrupted and their content was replaced by a great number of pleomorphic mycoplasma.This investigation was supported by a grant of Consiglio Nazionale delle Ricerche, Rome. 相似文献
4.
Morphology, Ultrastructure, and Bacteriophage Infection of the Helical Mycoplasma-Like Organism (Spiroplasma citri gen. nov., sp. nov.) Cultured from “Stubborn” Disease of Citrus
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Roger M. Cole Joseph G. Tully Terry J. Popkin Joseph M. Bov 《Journal of bacteriology》1973,115(1):367-386
The mycoplasma-like organism Spiroplasma citri gen. nov., sp. nov., isolated from citrus infected with “Stubborn” disease and carried in serial cultures in several media, was examined by dark-field microscopy and electron microscopy of negatively-stained and shadowed preparations and of sections. It grows as motile, helical filaments in liquid, but as nonmotile, nonhelical filaments and round bodies in agar cultures. Helicity and motility are lost in old broth cultures and upon addition of a variety of negative stains, fixatives, and other solutions. No organelles accounting for motility are present, but a layer of surface projections is present on the surface of the single, bounding membrane. The mycoplasma produces a tailed, type B bacteriophage which appear to attach to the outer layer. Helical filaments are preserved in ammonium molybdate, but not in sodium phosphotungstate, and by fixation in Formalin or glutaraldehyde made up in medium, but not by osmium nor by glutaraldehyde in cacodylate buffer. This mycoplasma appears similar to the noncultured helical microorganism in corn stunt-diseased tissues and is probably a representative of a new group of mycoplasmas which are in possession of surface projections, rotary motility, and bacteriophage infection. 相似文献
5.
桑萎缩病的类菌原体病原物及其超微病变特征 总被引:4,自引:0,他引:4
对感染桑萎缩病的桑叶及嫩梢进行超薄切片的电镜观察发现,其韧皮部组织,筛管及伴胞内有多型性类菌原体。菌体为圆形及椭圆形,大小约为50~160nm,双层膜,厚度约为8~10nm,内含物中具有核质样的纤维状物质,而在健株叶梢中未观察到任何病原体.随着病害的发展,可观察到细胞成份的降解。第一,在感病植株叶肉细胞内存在部分细胞核的降解、核膜破裂或核质流失甚至核仁分散消失。第二,叶绿体内有不同程度的淀粉粒和嗜锇颗粒累积,部分叶绿体外膜破裂,基质流失,基粒降解。第三,线粒体及粗面内质网在数量上有所增加,部分线粒体嵴已降解。 相似文献
6.
Histopathological and cytopathological abberations detected by anatomy and staining reactions indicated the association of mycoplasma-like organisms with the little leaf disease of eucalypt in Kerala. These light and fluorescent microscopic techniques, specially dienes ’reaction, can be used routinely to distinguish between little leaf disease caused by mycoplasma-like organisms and little leaf induced by some other factor. 相似文献
7.
By using electron microscopy pleomorphic mycoplasma-like bodies were observed only in the phloem cells of the field infected potato plants showing purple top roll symptoms. The bodies surrounded by unit membranes were 50–300 nm in diameter. 相似文献
8.
Mycoplasma-like Organisms in Narcissus sp. 总被引:1,自引:0,他引:1
Abstract The use of electron and optical fluorescent microscope confirmed the presence of mycoplasma-like organisms (MLO) in Narcissus sp. plants showing leaf chlorosis, phyllody and degenerated flowers. Unidentified multivesicular membrane bounded bodies were also found in some sieve tubes of the diseased plants. 相似文献
9.
Mycoplasma-like organisms were seen in eight of twenty trees affected by sudden death disease from the islands of Zanzibar and Pemba. Vesicular bodies were also seen in the phloem of a further six affected trees but did not possess all the characteristics of mycoplasma-like organisms. No virus-like particles were found in any of the twenty sudden death trees examined. 相似文献
10.
Mycoplasma-like bodies were found by electron microscopy in the sieve tubes of blackberry, loganberry and raspberry plants showing symptoms of Rubus stunt disease, but not in those of normal plants. Watering diseased blackberry plants with aureomycin caused remission of the symptoms and greatly decreased the number of mycoplasma-like bodies. 相似文献
11.
Phyllody and apostasis of cassava plants were frequently observed during recent disease surveys in the Cauca Valley of Colombia. Many valuable cassava clones have been affected rendering them unsuitable for hybridization. Light and electron microscopic observations have revealed the presence of mycoplasma-like organisms in the diseased phloem tissues. The causal agent is sensitive to tetracycline and streptomycin at 1000 ppm a. i., but not to penicillin. 相似文献
12.
A previously undescribed disease onLupinus hybrids manifesting typical witches broom symptoms occurred spontaneously in a locality in North Bohemia. Broomed shoots appeared only in late summer and resulted from the abnormal proliferation of dormant axillary buds in leaf and fruit axils. The shoots were bushy and their leaves were dark green and not reduced in size. Electron micrographs of ultrathin sections showed the presence of numerous mycoplasma-like organisms (MLO) in diseased but not healthy phloem tissues. 相似文献
13.
Renate Eberl 《Symbiosis (Philadelphia, Pa.)》2010,51(1):107-116
Studies of microbial associations of intertidal isopods in the primitive genus Ligia (Oniscidea, Isopoda) can help our understanding of the formation of symbioses during sea-land transitions, as terrestrial
Oniscidean isopods have previously been found to house symbionts in their hepatopancreas. Ligia pallasii and Ligia occidentalis co-occur in the high intertidal zone along the Eastern Pacific with a large zone of range overlap and both species showing
patchy distributions. In 16S rRNA clone libraries mycoplasma-like bacteria (Firmicutes), related to symbionts described from
terrestrial isopods, were the most common bacteria present in both host species. There was greater overall microbial diversity
in Ligia pallasii compared with L. occidentalis. Populations of both Ligia species along an extensive area of the eastern Pacific coastline were screened for the presence of mycoplasma-like symbionts
with symbiont-specific primers. Symbionts were present in all host populations from both species but not in all individuals.
Phylogenetically, symbionts of intertidal isopods cluster together. Host habitat, in addition to host phylogeny appears to
influence the phylogenetic relation of symbionts. 相似文献
14.
Plasma membranes were isolated from Thermoplasma acidophila, a mycoplasma-like organism which grows optimally at pH 2 and 59 degrees. Cells in concentrated suspensions were lysed by titrating to pH 9.3. The membranes were purified by washing at pH 10 and centrifuging in a discontinuous sucrose gradient. Membrane purity was assessed by electron microscopy, determination of deoxyribonucleic acid content, polyacrylamide gel electrophoretic behavior. Gel patterns and amino acid composition of cells and membranes were found to differ significantly. The lipid contained small amounts of fatty acid esters and larger amounts of branched long-chain alkyl ethers. 相似文献
15.
A mycoplasma-like microorganism was identified on electron micrographs of ultrathin sections of roots and abnormal underground sprouts growing from roots of young apple trees artificially infected with the proliferation disease. Specimens taken in November, contained mycoplasmas at various stages of reproduction in sieve tubes of the host. Mycoplasma-like bodies occurred especially in abnormal underground sprouts, and rarely also in lateral roots. 相似文献
16.
In juvenile wild rats, bronchus-associated lymphoid tissue (BALT) development was similar to that seen in adult specified-pathogen-free rats. In adult wild rats the BALT was widespread. In one animal infected with a mycoplasma-like organism, a region of bronchoepithelium overlying a large BALT nodule was seen, through which lymphocytes appeared able to pass to make direct contact with the bronchial lumen: the significance of this observation is discussed. There was no evidence of infection in lungs from any of the specified-pathogen-free animals, where small foci of BALT were seen. 相似文献
17.
Rapid preparation of DNA from phytopathogenic mycoplasma-like organisms for polymerase chain reaction analysis 总被引:1,自引:0,他引:1
A simple procedure for the processing of MLO (mycoplasma-like organisms)-infected plant samples for PCR analysis is described. It is based on differential centrifugation and removal of enzyme inhibiting agents with the aid of a resin. Results of the amplifications are comparable with those achieved with more complex DNA extraction procedures. The method does not require any extraction with organic solvents or alcoholic precipitation of nucleic acids. 相似文献
18.
Alfalfa witches’ broom manifested by an expressive increase in the number of stems and dwarfing of the affected plants was found in Czechoslovakia. The disease is not saptransmissible and was transmitted by grafting to healthy alfalfa plants. The disease occurrence is sporadic. The symptoms observed in comparison with those described in Australia and USA are mild and inconspicuous. Electron micrographs of ultrathin sections showed the presence of numerous mycoplasma-like organisms (MLO) in diseased but not in healthy phloem tissues. 相似文献
19.
The mycoplasma-like disorders associated with the aster yellowsand peach X-disease decreases the chorophyll and protein constituentsof Vinca rosea L. The reduction in total chlorophyll and proteinsare quantitative for both disorders but there is a preferentialreduction of chlorophyll a with respect to chlorophyll b inthe peach X-disease.
1 Contribution from the Missouri Agricultural Experiment Station.Journal Series No. 7750, approved by the Director. (Received August 9, 1977; ) 相似文献
20.
R. Credi 《Journal of Phytopathology》1994,142(4):310-316
Pathological changes in Vitis vinifera cv. Caveccia phloem from leaves showing symptoms of a flavescence doreé-like disease consisted of obliteration, necrosis and collapse of the sieve elements and associated companion cells, and excessive callose accumulation in lateral sieve areas and sieve plates of apparently normal mature sieve elements. Unusual structures, also found in degenerate sieve elements of diseased leaf vein specimens, were strongly electron-dense and bounded by a unit membrane or an electron-transparent border, and considered to be senescent forms of mycoplasma-like organisms. The significance of these findings in relation to possible host responses to the yellows pathogen is discussed. 相似文献