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11.
Meloidogyne californiensis n. sp. is described and illustrated from bulrush Scirpus robustus in California. LM and SEM studies revealed that this species differs from other known species in the genus Meloidogyne especially by the prominent posterior cuticular protuberances in the female, the distinct shape of the perineal pattern which is marked by one prominent stria in the perineum, indistinct lateral lines, many broken discontinuous striae on both sides of the arch, and the excretory pore being located posterior to stylet base. Second-stage juveniles 448-628 μm long, stylet length 11-13 μm, styler delicate, with small knobs sloping posteriorly, cephalic region with 2 or 3 annuli, and inflated rectum. Males vary greatly in size (712-1,952 μm), stylet length 18-28 μm (mean 22 μm), cephalic region slightly set off the body with two or three annuli, spear heavy with massive rounded knobs, lateral field marked by four areolated incisures as seen by SEM. 相似文献
12.
13.
Phorbol esters are known to alter microfilaments but it is not clear if the changes correspond to modulation of the phosphoinositide turnover/protein kinase C system. The novel technique of laser scanning confocal epifluorescence was used to study fiber orientation in phorbol ester treated cells. We treated endothelial cells with control agents and agents known to stimulate protein kinase C: 4 alpha-phorbol, phorbol 12-myristate 13-acetate (PMA), phorbol dibutyrate (PDB), or lipopolysaccharide. After incubation with the test agents, the endothelial cell microfilaments were stained with rhodamine pholloidin and viewed by conventional epifluorescence and by laser scanning confocal epifluorescence microscopy. The images obtained by the confocal microscopy corresponded to a thin optical section through the cells, 300 nm or more in thickness. The microfilaments extended predominantly in the plane of focus. After exposure of the cells to phorbol esters, the stress fibers became more nearly parallel in arrangement or were shortened, but remained in the plane of focus. The modification of microfilaments in response to phorbol esters was quantitated by a single blind analysis. In order to compare the morphological changes with a biochemical action of the phorbol esters, we measured phosphoinositide turnover. The dose-dependence of morphological changes was compared and contrasted to the dose-dependent effect of phorbol esters on bradykinin-stimulated phosphoinositide turnover. PMA had about the same EC50 (1-5 nM) for both biochemical and morphological processes. PDB was less potent in inducing the disruption of microfilament structure than in inhibiting phosphoinositide turnover. Lipopolysaccharide was ineffective in inducing a morphological change under these conditions. A simple activation of protein kinase C is insufficient to explain the dose-dependent effects of phorbol esters. Thus a morphometric analysis can help distinguish the potency of cytoskeleton modulators. 相似文献
14.
D E Olins A L Olins M Robert-Nicoud T M Jovin J Wehland K Weber 《Biology of the cell / under the auspices of the European Cell Biology Organization》1989,66(3):235-246
Detergent permeabilized Euplotes eurystomus (a fresh water hypotrichous ciliate) was reacted with monoclonal and polyclonal antibodies specific for either detyrosinated or tyrosinated alpha-tubulin (Glu- or Tyr-tubulin). The isolated cytoskeleton-nuclear complex was examined by Western immunoblotting and by immunofluorescent and electron microscopic methods. Both Glu- and Tyr-tubulins were detected by immunoblot analysis. Immunofluorescent microscopy indicated that the alpha-tubulin isotypes are concentrated in different regions of permeabilized cells: Glu-tubulin is located primarily in cirri, membranelles, and surrounding the macro- and micronuclei. Tyr-tubulin is principally at the bases of cirri and membranelles. This differential distribution of alpha-tubulin isotypes is discussed in terms of current concepts concerning the correlation of tubulin post-translational modifications to microtubule stability. Confocal immunofluorescent imaging was of critical importance in clearly differentiating the Glu-tubulin isotype surrounding the macro- and micronuclei from a brilliantly fluorescent environment originating from cytoskeletal structures. In conjunction with conventional and stereo-electron microscopy, confocal optical microscopy provided convincing evidence for a "basket" of microtubules surrounding both nuclei. 相似文献
15.
P. J. Skuce C. F. Johnston I. Fairweather D. W. Halton C. Shaw K. D. Buchanan 《Cell and tissue research》1990,261(3):573-581
Summary The presence and distribution of neuropeptides belonging to the pancreatic polypeptide family have been demonstrated by an indirect immunofluorescence technique in the nervous systems of adult male and female Schistosoma mansoni. Seven antisera of differing regional specificity to pancreatic polypeptide (PP), peptide YY (PYY) and neuropeptide Y (NPY) were employed on both whole-mount and cryostat-sectioned material. Positive immunoreactivity (IR) was obtained with all antisera except an N-terminally-directed antiserum to NPY. In the CNS, immunoreactivity was restricted to cell bodies and nerve fibres in the anterior ganglia, central commissure and dorsal and ventral nerve cords of both sexes, whereas, in the PNS, positive-IR was present in the plexuses innervating the subtegumental musculature and the oral and ventral suckers. Intense immunoreactivity was observed in a plexus of nerve fibres and cell bodies in the lining of the gynaecophoric canal and in fine nerve fibres innervating the dorsal tubercles of the male. In contrast, in the female, strong immunoreactivity was evident in nerve plexuses innervating the lining of the ovovitelline duct and in the wall of the ootype, but most notably in a cluster of cells in the region of Mehlis' gland. Results suggest that molecules with C-terminal homology to the PP-family are present in S. mansoni. These peptides would appear to be important regulatory molecules in the parasite's nervous system and may play a role in the control of egg production. 相似文献
16.
A technique is described for using standard squash preparations of mitotic and meiotic chromosomes for both light microscopy
and subsequent high-resolution scanning electron microscopy for investigation of the same specimen. Depending on the microscope
and conditions of preparation, a resolution of a few nanometers is routinely possible. Tilting of the specimen provides a
three-dimensional insight into chromosomal structures. Combination of material-dependent signals of backscattered electrons
with the secondary electron image allows an unambiguous localization of surface markers. 相似文献
17.
Meloidogyne mayaguensis n. sp. is described and illustrated from specimens obtained from galled roots of eggplant, Solanum melongena L., from Puerto Rico. The perineal pattern of females is round to ovoid with fine, widely spaced striae. It has occasional breaks of striation laterally and a circular tail tip area lacking striae. The stylet, 15.8 μm long, has reniform knobs that merge gradually with the stylet shaft. Males have a high, rectangular, smooth head region, not set off from the body contour. The labial disc is continuous with the medial lips which do not slope posteriorly. The styler, 22.9 μm long, has large rounded backward sloping knobs; the shaft is of uneven diameter. Mean body length of second-stage juveniles is 453.6 μm. The truncate head region is not annulated, and the rounded, slightly raised labial disc and the crescentic medial lips form dumbbell-shaped lip structures. The stylet, 11.6 μm long, has rounded, posteriorly sloping knobs. The slender tail, 54.4 μm long, gradually tapers to a bluntly pointed tip. Tomato, tobacco, pepper, and watermelon are good hosts; cotton and peanut are not hosts. M. mayaguensis n. sp. reproduces by mitotic parthenogenesis and has a somatic chromosome number of 2n = 44-45. The enzyme patterns are unique among Meloidogyne species. 相似文献
18.
Tylenchulus graminis n. sp. and T. palustris n. sp. are described and illustrated from broomsedge (Andropogon virginicus L.) and pop ash (Fraxinus caroliniana Mill.), respectively. T. graminis resembles T. furcus in having a distinct anus, but T. graminis second-stage juveniles (J2) do not have a bifid tail. T. semipenetrans does not have a perceptible anus. The mature female of T. graminis has a mucronate pointed terminus while T. semipenetrans has a smooth and round terminus. T. graminis males have wider stylet knobs and basal bulb and a longer tail than T. semipenetrans males. T. graminis J2 have a longer posterior body portion (without large fat globules) than T. semipenetrans J2. T. palustris resembles T. semipenetrans in having an undetectable anus but differs by the short and conoid mature female postvulval section. The male of T. palustris has larger stylet knobs and basal bulb than those of T. semipenetrans and a bluntly rounded tail terminus, which is tapered in T. semipenetrans. T. palustris differs from T. furcus and T. graminis in having an undetectable anus, by the conoid postvulval section of mature females, by the shorter and rounded tail of males, and the shorter J2 posterior body section without large fat globules. T. graminis and T. palustris are parasites of indigenous flora of Florida. 相似文献
19.
S. N. Kovalenko S. G. Stepanian V. P. Chuev M. M. Asimov V. M. Nikitchenko V. P. Chernykh 《Molecular Engineering》1992,2(2):153-163
In order to improve the generating and photochemical properties of coumarin laser dyes, the following active media were synthesized: inclusion complexes of -cyclodextrin (-CD) and 7-amino-4-methylcoumarins (COU1, COU102, COU120). Complex formation processes were studied, and the structure of the inclusion complexes was estimated using the method of MM2 molecular mechanics. The data obtained suggest the reasons underlying the complex structure effects on their spectral, luminescent and generating characteristics. 相似文献
20.