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1.
HAN-QI YANG HONG WANG DE-ZHU LI 《Botanical journal of the Linnean Society. Linnean Society of London》2008,156(3):411-423
The foliage leaf epidermis of 35 species representing 12 key genera of woody bamboos of the Asian tropics was investigated using light and scanning electron microscopy. The results indicated that papillae forms and distributional patterns around the stomatal apparatus of the abaxial foliage leaf epidermis were usually constant and were of great taxonomic significance at the specific and generic levels. However, papillae characters were not suitable for dividing subtribes within woody bamboos of the Asian tropics. On the basis of papillae characters, Schizostachyum s.s. and Cephalostachyum were confirmed, but their delimitations should be modified. The transfer of Leptocanna chinensis and Schizostachyum sanguineum into Cephalostachyum was supported, and Cephalostachyum virgatum and C . pergracile were confirmed to be members of Schizostachyum s.s. The subtribe Racemobambosinae did not obtain support and Racemobambos appeared to be better placed in subtribe Bambusinae. Neomicrocalamus was supported as a close relative and better treated as a synonym of Racemobambos . Gigantochloa was closely related to Dendrocalamus . © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society , 2008, 156 , 411–423. 相似文献
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Polypeptides of the Golgi Apparatus of Neurons from Rat Brain 总被引:4,自引:0,他引:4
An antiserum was raised against fractions of the Golgi apparatus of neurons from rat brain. Immunoblots of these fractions with the antiserum showed two principal bands of 185 and 150 kilodaltons (kd) in apparent molecular mass. The antiserum reacted with five or six bands of 200, 150, 130, 100-110, 64, and 40 kd in apparent molecular mass in immunoblots of several crude brain membrane fractions. Affinity-purified antibodies from the different gel bands transferred to nitrocellulose paper were used in immunoblot and immunocytochemical studies. Antibodies eluted from the 200-, 150-, 100-110-, and 64-kd bands reacted not only with the corresponding band but also with the other three bands. Antibodies eluted from the 40-kd band stained only the corresponding band. On light and/or electron microscopic immunocytochemistry, the antiserum stained the Golgi apparatus of rat neurons, glia, liver, and kidney tubule cells. Weaker, segmented, and less consistent staining was observed in nuclear envelopes, rough endoplasmic reticulum, and plasma membranes of neurons. Antibodies eluted from the bands at 200, 150, 100-110, and 64 kd stained intermediate cisterns of the Golgi apparatus of neurons. These findings suggest that a group of related polypeptides of brain membranes is preferentially expressed or enriched in the Golgi apparatus of neurons. Polypeptides with apparent molecular masses of 185 and 150 kd probably represent moieties endogenous to membranes of the neuronal Golgi apparatus. 相似文献
4.
Andreas Körte Vera Forsbach Thomas Gottenöf Gerhard Rödel 《Molecular & general genetics : MGG》1989,217(1):162-167
Summary Translation of mitochondrial cytochrome b mRNA in yeast is activated by the product of the nuclear gene CBS1. CBS1 encodes a 27 kDa precursor protein, which is cleaved to a 24 kDa mature protein during the import into isolated mitochondria. The sequences required for mitochondrial import reside in the amino-terminal end of the CBS1 precursor. Deletion of the 76 amino-terminal amino acids renders the protein incompetent for mitochondrial import in vitro and non-functional in vivo. When present on a high copy number plasmid and under the control of a strong yeast promoter, biological function can be restored by this truncated derivative. This observation indicates that the CBS1 protein devoid of mitochondrial targeting sequences can enter mitochondria in vivo, possibly due to a bypass of the mitochondrial import system. 相似文献
5.
The effect of excitation on the rate of respiration in the liverwort Conocephalum conicum 总被引:4,自引:0,他引:4
Simultaneous measurements were taken of the electrical activity and the rate of respiration of thalli of Conocephalum conicum L. stimulated electrically and mechanically (by cutting). The measurements of the rate of respiration employed a modified Warburg apparatus for O2 consumption and an infra-red gas analyzer with computer recording and data processing for CO2 evolution. The action potential, produced by either a cut (a damaging stimulus) or an electrical stimulus (a non-damaging stimulus), caused a transient rise in the rate of respiration. The course of changes in the rate of respiration depends on the character of the excitation and the area of the thallus covered by it. If stimulation does not produce excitation, the increase in the rate of respiration does not take place, regardless of the magnitude and type of the stimulus applied. 相似文献
6.
P A Coulombe M Bendayan 《Biology of the cell / under the auspices of the European Cell Biology Organization》1989,65(1):83-86
The membrane content in phospholipids along the secretory pathway in rat pancreatic B-cells was studied in situ by high-resolution cytochemistry, applying the recently introduced phospholipase A2-gold technique. The gold particles were mostly associated with cell membranes, and the various types of membranes were labeled to a different extent. Quantitation of the labeling over these membranes revealed a heterogeneous distribution of the labeling across the secretory pathway. This heretogeneity occurred mainly as a progressive, decreasing gradient in the first half of this pathway, between the rough endoplasmic reticulum and the mi-cisternae of the Golgi apparatus. The labeling density remained at a lower level in the trans-most Golgi cisternae and immature secretory granule membranes, to increase in the mature secretory granule membrane, where it reached the value found in the plasma membrane. These results provide evidence that the functional heterogeneity existing across the membrane forming the secretory pathway is parallelled by substantial changes in their phospholipid content. 相似文献
7.
A Rambourg Y Clermont M Chrétien 《Biology of the cell / under the auspices of the European Cell Biology Organization》1989,65(3):247-256
The tridimensional structure of the Golgi apparatus has been studied in the absorptive cells of the mouse colon by means of reduced osmium postfixation and phosphatase cytochemistry. In thick sections of tissue impregnated with osmium tetroxide or treated with a technique to demonstrate TPPase activity, the Golgi formed a continuous ribbon-like structure capping the upper pole of the nucleus. Along the longitudinal axis of this ribbon, compact zones made up of superposed flattened saccules alternated with less compact zones which consisted of highly perforated saccules or bridging anastomosed tubules. In the cis-trans axis, the following elements were observed: (1) a cis element consisting of a continuous osmiophilic tubular network; (2) two or three subjacent elements selectively perforated by wells; (3) a trans compartment made up of two or three TPPase-reactive sacculotubular elements, some showing a "peeling-off" configuration. In some regions, the first flattened saccule of this trans compartment displayed discrete ovoid dilatations, located in compact zones and containing a dense granulofibrillar material; in the subjacent elements this material was seen concentrated in nodular swellings, at the intersection of the meshes of anastomosed membranous tubules. 100-300 nm vesicles containing a similar dense granulofilamentous material were observed in the trans Golgi zone and interspersed in the supranuclear cytoplasm between the Golgi zone and the apical surface of the cell. Smaller vesicles 80-100 nm in diameter containing a fine dusty material were also seen in proximity. These morphological observations suggested that at least two kinds of material were segregated in the saccules of the trans compartment and packaged in vesicles of two class sizes that detached from the Golgi stack on its trans aspect. 相似文献
8.
Summary It is difficult to distinguish between Goormaghtigh cells (G-cells) and media cells of the glomerular arterioles at the border of the Goormaghtigh cell field. Consequently, it has been unclear whether renin-positive G-cells are normally present and also whether renin-producing cells are recruited from the pool of renin-negative G-cells upon stimulation of the renin-angiotensin system (RAS). In the present study, immunohistochemical and electron-microscopic experiments have been carried out on serially sectioned kidney biopsies from four patients with pseudo-Bartter syndrome. The results strongly suggest that with longlasting stimulation of the RAS all renin-negative (secretory resting) G-cells are ultimately converted into renin-producing granular cells.Synonymous with extraglomerular mesangial cells 相似文献
9.
The light-harvesting complex of photosystem II (LHC II) contains one major (LHC IIb) and at least three minor chlorophyll-protein components. The apoproteins of LHC IIb (LHCP) are encoded by nuclear genes and synthesized in the cytoplasm as a higher molecular weight precursor(s) (pLHCP). Several genes coding for pLHCP have been cloned from various higher plant species. The expression of these genes is dependent upon a variety of factors such as light, the developmental stage of the plastids and the plant. After its synthesis in the cytoplasm, pLHCP is imported into plastids, inserted into thylakoids, processed to its mature form, and assembled into LHC IIb. The pathway of assembly of LHC IIb in the thylakoid membranes is currently being investigated in several laboratories. We present a model that gives some details of the steps in the assembly process. Many of the steps involved in the synthesis and assembly are dependent on light and the stage of plastid development.Abbreviations PS
Photosystem
- LHC II
Light-harvesting complex of PS II
- LHCP
Apoproteins of LHC IIb
- pLHCP
Precursor of LHCP
- PAGE
Polyacrylamide gel electrophoresis 相似文献
10.
Formation of wheat protein bodies: Involvement of the Golgi apparatus in gliadin transport 总被引:1,自引:0,他引:1
Developing wheat (Triticum aestivum L.) endosperm was examined using ultrathin sections prepared from tissues harvested at 5, 9, 16 and 25 d after flowering. Protein bodies were evident by 9 d and displayed a variety of membranous structures and inclusions. The Golgi apparatus was a prominent organelle at all stages, and by 9 d was associated with small electron-dense inclusions. By immunocytochemical techniques, gliadin (wheat prolamine) was localized within these vesicles and in homogeneous regions of protein bodies, but not in the lumen of the rough endoplasmic reticulum. The protein bodies appear to enlarge by fusion of smaller protein bodies resulting in larger, irregular-shaped organelles. The affinity of the Golgi-derived vesicles for gliadin-specific probes during the period of maximal storage-protein synthesis and deposition indicates that this organelle includes the bulk, if not all, of the gliadin produced. The involvement of the Golgi apparatus in the packaging of gliadins into protein bodies indicates a pathway which differs from the mode of prolamine deposition in other cereals such as maize, rice and sorghum, and resembles the mechanism employed for the storage of rice glutelin and legume globulins.Abbreviations ER
endoplasmic reticulum
- IgG
immunoglobulin G
- DAF
days after flowering 相似文献