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1.
2.
After examining a large number of type and authoritative specimens of Schizophragma Siebold & Zucc., S. elliptifolium C. F. Wei and S. integrifolium var. glaucescens Rehder were reduced to synonyms of S. hypoglaucum Rehder and S. integrifolium f. cordatum S. Y. Wang was reduced to synonym of S. corylifolium Chun. Schizophragma crassum var. ellipticum J. Anthony was treated as the correct name of S. crassum var. hsitaoanum (Chun) C. F. Wei. The name S. integrifolium var. minus Rehder is reinstated. The taxonomic treatment is supported by leaf epidermal characters.  相似文献   

3.
The thylakoid membranes were isolated and purified from gametophyte of Porphyra yezoensis Ueda (P. yezoensis) by sucrose density gradient ultracentrifugation. After P. yezoensis gametophyte thylakoid membranes were solubilized with SDS, the photosystem Ⅱ (PSⅡ) particles were isolated and purified. The activity of PSⅡ  相似文献   

4.
As a group of intestinal hormones and neurotransmitters, cholecystokinins(CCKs) regulate and affect pancreatic enzyme secretion, gastrointestinal motility, pain hypersensitivity, digestion and satiety, and generally contain a DYMGWMDFG sequence at the C-terminus. Many CCKs have been reported in mammals. However, only a few have been reported in amphibians, such as Hyla nigrovittata, Xenopus laevis, and Rana catesbeiana, with none reported in urodele amphibians like newts and salamanders. Here, a CCK called CCK-TV was identified and characterized from the skin of the salamander Tylototriton verrucosus. This CCK contained an amino acid sequence of DYMGWMDF-NH2 as seen in other CCKs. A c DNA encoding the CCK precursor containing 129 amino acid residues was cloned from the c DNA library of T. verrucosus skin. The CCK-TV had the potential to induce the contraction of smooth muscle strips isolated from porcine gallbladder, eliciting contraction at a concentration of 5.0x10-11 mol/L and inducing maximal contraction at a concentration of 2.0x10-6 mol/L. The EC50 was 13.6 nmol/L. To the best of our knowledge, this is the first report to identify the presence of a CCK in an urodele amphibian.  相似文献   

5.
Abstract:Inthispaper,anon-hierarchicalagglomerativealgorithm,stepwiseclustering(SWC)analysisisintroducedinvegetationanalysisbyapplicationtotheE-laeagnusmolliscommunityofshanxi,NorthChina.ByusingSWCanalysis,classifica-tionisreachedbysuccessivelyadjustingthemembersofplotgroupssothatthesum-of-Squares,similartothecoefficientofdistance,isminimizedwithineachplotgroup.Thedesiredsignificantcharacteristicofmaximalhomogeneitywithineachplotgroup,butmaximalheterogeneityamongplotgroupsisthusachieved.TheresultsofanalysisbySWCiscomparedwiththoseoffuzzyc-meansalgorithmclustering(FCAC),andTWINSPAN.TheuseofSWCispreferabletoTWINSPANduetotherelaxationofthepreconditionofthe1atterofahierarchicalre1ationshipamongplotgroups.ComparingSWCwithFCAC,theformerissuperiorsincetheresultoftheanalysisismoreinaccordancewiththeactualvegetationdistribution,asshownbyx~2testofindependence.  相似文献   

6.
Floral morphogenesis and the development of Cercidiphyllumjaponicum Sieb. et Zucc. were observed by scanning electron microscopy (SEM). The results showed that the pistillate inflorescences were congested spikes with the flowers arranged opposite. Great differences between the so-called "bract" and the vegetative leaf were observed both in morphogenesis and morphology. In morphogenesis, the "bract" primordium is crescent-shaped, truncated at the apex and not conduplicate, has no stipule primordium at the base but does have some inconspicuous teeth in the margin that are not glandular. The leaf primordium is triangular, cycloidal at the apex, conduplicate, has two stipule primordia at the base, has one gland-tooth at the apex occurring at first and some gland-teeth in the margin that occur later. In morphology, the "bract" is also different to the vegetative leaf in some characteristics that were also illustrated in the present paper. Based on the hypothesis that the bract is more similar to the vegetative leaf than the tepal, we considered that the so-called "bract" of C.japonicum might be the tepal of the pistillate flower in morphological nature. Therefore, each pistillate flower contains a tepal and a carpel. We did not find any trace of other floral organs in the morphogenesis of the pistillate flower. Therefore we considered that the unicarpellate status of extant Cercidiphyllum might be to highly reduce and advance characteristics that make the extant Cercidiphyllum isolated from both fossil Cercidiphyllum-like plants and its extant affinities.  相似文献   

7.
Phytophthora infestans is a highly destructive plant path- ogen that causes late blight disease in plants such as potato and tomato (Fry and Goodwin, 1997). As a typical oomycete, the primary infective propagule of P. infestans is the sporangium, which can either germinate directly or release biflagellate zoospores that encyst and germinate on the host subsequently (Grenville-Briggs et al., 2005). Due to abundant formation of the sporangia and prolific sporulation, P. infestans can spread quickly in the host tissues and cause extensive necrosis of the infected plants (Kamoun and Smart, 2005).  相似文献   

8.
By laser scanning fluorescence microscopy for quantitative measurement of fluorescence intensity changes on egg surface stained with fluorescein isothiocyanate during cleavage furrow extending forward,it was found that in area of presumptive cleavage furrow the scanning curve became ∨ shape,indicating dark stripe appeared in that place.Then the fluorescence intensity increased at the place where the bottom of ∨ shape had located,and the scanning curve turned to ∧ shape,indicating single stripe was formed.While enhanced fluorescence appeared on the borders of ∧ shape,an M shape curve was found,showing double stripe occurred.During the distance between two borders of M shape incresing from 50μm to 100μm,a fluorescence peak came to sight in the middle of the M shape,which being the cleavge furrow bottom.The two lateral sides of furrow bottom with decreasing fluorescence were nascent membrane.At that time the curve became W shape.By the sides of cleavage furrow the the stress folds became conspicous after double stripe stage,showing the stretching of the egg surface being increased.With our[31,33]and others[32] reports that polylysine could induce the appearance of nascent membrane and phytohemagglutinins could decrease or prevent the appearance of nascent membrane,we believed the idea of Schroeder[25] that increasing mechanical stress could initiate nascent membrane formation and thought that the stresslay to the outsides of cleavage furrow.  相似文献   

9.
Morphological structure and optical properties of the wings of Morphidae   总被引:2,自引:0,他引:2  
The morphological structure and optical properties of the wings of 14 species of Morphidae have been investigated. Most of the scales of the iridescent species of Morphidae (Lepidoptera) present a very particular structure. The ground scales, responsible for the major part of the optical properties, are covered by a very regular set of longitudinal ridges. The ridges themselves are constituted by a superposition of lamellae that act locally as a multilayered structure. This very specific morphology leads to both interferences and diffraction effects. The first one is responsible of the brilliant blue coloration of the males, while the second one diffracts this colored light at a very large angle. These two phenomena give to the butterfly a very effective long-range communication system. The morphological characteristics of the scales of the various species are presented in detail. Two types of optical measurement were performed on the iridescent wings of 14 different species of Morphidae: spectroscopic measurements under various incidences and gonioscopic measurements for a given incidence angle and wavelength. The first allows a determination of the index of refraction of the cuticular material. The second leads to the drawing of spatial diffraction maps. It shows that most of the reflected light is diffracted laterally over a very large angle (90° 〈 0 〈 120°, according to the different species) and that this repartition depends of the polarization of incident light. As predicted by previous calculations, the dissymmetric structure of the ridge is responsible for the separation of the polarization modes in the various diffraction orders.  相似文献   

10.
Legionella pneumophila, the causative agent of Legionnaires' disease, has been recognized as a major health problem responsible for an estimated number of 15 000-30 000 cases of severe pneumonia per year in Germany alone. Despite of the high clinical relevance, many aspects of the intracellular life-cycle of Legionella, especially details on interactions with host cells, are not well understood. Structural information on virulence proteins helps unravel basal pathogenicity mechanisms and is a prerequisite for the rational development of effective drug molecules. Here we discuss structures of three important virulence proteins of Legionella that have been determined in our laboratory. The structure of the macrophage infectivity potentiator (Mip) protein of Legionella pneumophila is the first of a novel subgroup within the family of FK506-binding protein (FKBP) peptidyl-prolyl cis/trans isomerases. On the basis of the Mip structure, promising antibacterial agents are being designed. Recently, structures of two equally exciting Legionella proteins have been reported. The ferrous iron transport protein FeoB is a transmembrane protein responsible for Fe2+ aquisition after entry of the pathogen into the host cell. The structure of the cytoplasmic domain of ferrous iron transporter (FeoB) provides insights into the family of prokaryotic G proteins and allows a detailed comparison with structures of related FeoBs. Furthermore, the characterization of DegQ, a periplasmatic chaperone-protease involved in protein quality control represents an intriguing example of how enzymatic activity is regulated by oligomerization as well as by an intrinsic loop activation cascade, depending on subtle conformational rearrangements.  相似文献   

11.
Sequence alignment is a common method for finding protein structurally conserved/similar regions. However, sequence alignment is often not accurate if sequence identities between to-be-aligned se- quences are less than 30%. This is because that for these sequences, different residues may play similar structural roles and they are incorrectly aligned during the sequence alignment using substitu- tion matrix consisting of 20 types of residues. Based on the similarity of physicochemical features, residues can be clustered into a few groups. Using such simplified alphabets, the complexity of protein sequences is reduced and at the same time the key information encoded in the sequences remains. As a result, the accuracy of sequence alignment might be improved if the residues are properly clustered. Here, by using a database of aligned protein structures (DAPS), a new clustering method based on the substitution scores is proposed for the grouping of residues, and substitution matrices of residues at different levels of simplification are constructed. The validity of the reduced alphabets is confirmed by relative entropy analysis. The reduced alphabets are applied to recognition of protein structurally conserved/similar regions by sequence alignment. The results indicate that the accuracy or efficiency of sequence alignment can be improved with the optimal reduced alphabet with N around 9.  相似文献   

12.
Editor-in-ChiefREN Lu-quanProfessor, Key Laboratory of Terrain-Machine Bionics Engineering (Ministry of Education, China), Jilin University atNanling Campus,'5988 Renmin Street, Changchun 130022, P. R. ChinaAssociate Chief EditorsJulian F. V. Vincent TONG JinProfessor, Center for Biomimetics and Natural Technologies, Professor, Key Laboratory of Terrain-Machine Bionics EngineeringDepartment of Mechanical Engineering, (Ministry of Education, China), Jilin University at N…  相似文献   

13.
1942YaoT,SPai.HeteropycnosisandchromatindiminutioninCosmocercasp.Sci-enceRecord1(1-2)197-202.1944PaiS,TYao.DieChromosomenderundifferenzirtenSomazellenandKeimba-bnzellenvonCosmocercasp.TheChineseJExpBiol2(1)1-8.1945aYaoT.StudiesontheorgainzerprobleminPelmatohydraoligactis.Ⅰ.Theinductionpotencyoftheimplantsandthenatureoftheinducedhydranth.JExpBiol21(3-4)147-50.1945bYaoT.StudiesontheorganizerprobleminPelmatohydraoligactis.Ⅱ.Theeffectofsomerespiratoryinhibitorsandstimulantsandofoxyge…  相似文献   

14.
AIM To identify and characterize the effect of phosphorylation on the subcellular localization of Ankrd54.METHODS HEK293 T cells were treated with calyculin A, staurosporin or phorbol 12-myristate 13-acetate(PMA). Cells were transfected with eG FP-tagged Ankrd54 with or without Lyn tyrosine kinase(wild-type, Y397 F mutant, or Y508 F mutant). The subcellular localization was assessed by immunofluorescence imaging of cells, immunoblotting of subcellular fractionations. The phosphorylation of Ankrd54 was monitored using Phos-tagT M gel retardation. Phosphorylated peptides were analysed by multiplereaction-monitoring(MRM) proteomic analysis.RESULTS Activation of PKC kinases using PMA promoted nuclear export of Ankrd54 and correlated with increased Ankrd54 phosphorylation, assayed using Phos-tag TM gel retardation. Co-expression of an active form of the PKCδisoform specifically promoted both phosphorylation and cytoplasmic localization of Ankrd54, while PKCδ, Akt and PKA did not. Alanine mutation of several serine residues in the amino-terminal region of Ankrd54(Ser14, Ser17, Ser18, Ser19) reduced both PMA induced cytoplasmic localization and phosphorylation of Ankrd54. Using MRM proteomic analysis, phosphorylation of the Ser18 residue of Ankrd54 was readily detectable in response to PMA stimulation. PMA stimulation of cells co-expressing Ankrd54 and Lyn tyrosine kinase displayed increased coimmunoprecipitation and enhanced co-localization in the cytoplasm.CONCLUSION We identify phosphorylation by PKCδ as a major regulator of nuclear-cytoplasmic shuttling of Ankrd54, and its interaction with the tyrosine kinase Lyn.  相似文献   

15.
Actin cytoskeleton undergoes rapid reorganization in response to internal and external cues. How the dynamics of actin cytoskeleton are regulated, and how its dynamics relate to its function are fundamental questions in plant cell biology. The pollen tube is a well characterized actin-based cell morphogenesis in plants. One of the striking features of actin cytoskeleton characterized in the pollen tube is its surprisingly low level of actin polymer. This special phenomenon might relate to the function of actin cytoskeleton in pollen tubes. Understanding the molecular mechanism underlying this special phenomenon requires careful analysis of actin-binding proteins that modulate actin dynamics directly. Recent biochemical and biophysical analyses of several highly conserved plant actin-binding proteins reveal unusual and unexpected properties, which emphasizes the importance of carefully analyzing their action mechanism and cellular activity. In this review, we highlight an actin monomer sequestering protein, a barbed end capping protein and an F-actin severing and dynamizing protein in plant. We propose that these proteins function in harmony to regulate actin dynamics and maintain the low level of actin polymer in pollen tubes.  相似文献   

16.
Phenyl, p-tolyl, and p-tert-butylphenyl β-1-thio-N-acetylglucosaminides were synthesized by the treatment of thiophenols with peracetate of α-D-glucosaminyl chloride in the presence of triethylamine or under the conditions of phase-transfer catalysis with quaternary ammonium salts. The compounds synthesized were used for obtaining of glycosides of 4,6-O-isopropylidene-N-acetylmuramic acid, which were coupled with L-Ala-D-Glu(NH2)-OBzl and then deprotected to obtain the target aryl β-thioglycosides of N-acetylmuramyl-L-analyl-D-isoglutamine (MDP). The aryl β-thioglycosides of MDP were found to stimulate an antibacterial resistance toward Staphylococcus aureus in mice. The reliable induction of the spontaneous activity of natural killers in the population of blood mononuclear cells was observed only for phenyl β-thio-MDP at a dose of 200 μg/ml. Original Russian Text ? A.E. Zemlyakov, V.N. Tsikalova, L.R. Azizova, V.Ya. Chirva, E.L. Mulik, M.V. Shkalev, O.V. Kalyuzhin, M.V. Kiselevsky, 2008, published in Bioorganicheskaya Khimiya, 2008, Vol. 34, No. 2, pp. 245–251.  相似文献   

17.
《遗传学报》2008,35(1):I0003-I0006
Name Field of Research Interest Contact Address E-mail Address Advisor Shouyi Chen Plant molecular genetics Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China sychen@genetics.ac.cn Zhu Chen Medical genetics , Genomics Institute of Blood, Ruijin Hospital, Shanghai 200025 zchen@stn.sh.cn Jiayang Li Plant molecular genetics Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China jyli@geneti…  相似文献   

18.
1. The background is a maple leaf, whose vein is the transformation of the first letter of "Jiu", that is J. In the front, there is a waterfall, which is the transformati on of Z, the first letter of Zhai. This makes "Jiuzhai" obvious. The first letter of China, "C", is transformed into a globe, symbol-  相似文献   

19.
(Continued)The equipment and environment in the premises must conform to European legislation meeting quality standards as well as health and safely requirements. The following conditions must be met:Ⅰ. BRC laboratories are clean and well itⅡ. No source of excessive or unusual microbial contamination is introducedⅢ. Adequate bench and storage space is provided, consistent with the type and volume of work,Ⅳ. An appropriate containment facility is available to protect the work and worker from potential release of aerosols containing microorganisms or hazardous chemicals.  相似文献   

20.
The change of cholinergic transmission of p-amyloid protein (P-AP) treated rats was studied by intracerebral microdialysis sampling combined with HPLC analysis. β-AP1-40 was injected into nucleus basalis magnocellularis (NBM). Passive avoidance response test (step-down test) and delayed alternation task were used for memory testing. The impairment of memory after injection of β-AP1-40 into NBM exhibited mainly the deficiency of short-term working memory. One week after injection of β-AP1-40 the release of acetylcholine (ACh) from frontal cortex of freely-moving rats decreased significantly, and the response of cholinergic nerve ending to the action of high [K+] solution was rather weak. In control animals the percentage of increase of ACh-release during behavioral performance was 57%, while in β-AP1-40-treated rats it was 34%. The temporary increase of the ACh-release of the rat put into a new place was also significantly diminished in β-AP1-40 -treated rats. The results show that the injection of   相似文献   

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