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1.
The RNA binding capacity of 50S proteins from E. coli ribosomes has been tested under improved conditions; purified proteins active in reconstitution assays were used, and the binding was studied under the conditions of the total reconstitution procedure for the 50S subunit. The results are: 1) Interaction of 23S RNA was found with 17 proteins, namely L1, L2, L3, L4, L7/L12, L9, L10, L11, L15, L16, L17, L18, L20, L22, L23, L24 and L29. 2) The proteins L1, L2, L3, L4, L9, L23 and L24 bound to 23S RNA at a level of about one copy per RNA molecule, whereas L20 could bind more than one copy (no saturation was observed at 1.8 copies per 23S RNA), and the other proteins bound 0.2--0.6 copies per RNA. 3) L1, L3, L7/L12 showed a slight binding to 16S RNA, L26 (identical with S20) strong binding to 16S RNA. 4) The binding of L2, L7/L12, L10, L11, L15, L16 and L18 was preparation sensitive, i.e. the binding ability changed notably from preparation to preparation. 5) All proteins bound equally well to 23S RNA in presence of 4 and 20 mM Mg2+, respectively, except L2, L3, L4, L7/L12, L9, L10, L15, L16 and L18, which bound less strongly at 20 mM than at 4 mM Mg2+.  相似文献   

2.
Leptus larvae (Acarina:Erythraeidae) of Australia and New Guinea, collected either free-living or ectoparasitic on Arachnida or lower Insecta, are comprehensively reviewed. For Australia the following new species are described. From Scorpionida: L. barmeedius, L. baudini, L. carduus, L. hitchcocki, L. korematus, L. pistoris, L. stnithi and L. urodaci; from Araneae: L. minno; from Insecta: L. norrisi (Archaeognatha); L.flindersi (Blattodea); L. cheesmanae (Phasmatodea); L. bankensis, L. calcar, L. cultellus, L. foliatus, L. lighti, L. pincheni and L. tindalei (Orthoptera, Acridoidea); L. batjallus, L. clavatus, L. clelandi. L. elderi, L.fisheri (Hemiptera); L. grossi and L. puniceus (free-living only); some of the preceding species were also captured free-living. From Papua New Guinea the following new species are described: L. calcar (Acridoidea); L. cheesmanae (Orthoptera:'cricket') (both of these species also from Australia); L. lorarius, L. scutellatus and L. triacanthus (free-living). Additional host and other records are given for previously described species, originally described as ectoparasites of Insecta:from Australia: L. bathypogonus Womersley (Acridoidea); L. cerambycius Southcott (free-living); L. charon Southcott (Araneae, Scorpionida); L.faini Southcott (Araneae); L. orthrius Southcott (Hemiptera); from Papua New Guinea: L. draco Southcott (Odonata, Acridoidea, Tettiginioidea, Phasmatodea, Hemiptera). Protonymphs are described of L. barmeedius, L. baudini, L. calcar, L. charon, L.flindersi, L. orthrius and L. smithi. Deutonymphs are described of L. calcar, L. charon, L. flindersi and L. smithi. A key is provided for the known larvae, protonymphs and deutonymphs of Leptus of Australia and Papua New Guinea. Teratological abnormalities are recorded for L. cultellus, L. fisheri, L, minno and L. urodaci.  相似文献   

3.
The 60S ribosomal proteins were isolated from ribosomes of human placenta and separated by reversed phase HPLC. The fractions obtained were subjected to trypsin and Glu-C digestion and analyzed by mass fingerprinting (MALDI-TOF), MS/MS (ESI), and Edman sequencing. Forty-six large subunit proteins were found, 22 of which showed masses in accordance with the SwissProt database (June 2002) masses (proteins L6, L7, L9, L13, L15, L17, L18, L21, L22, L24, L26, L27, L30, L32, L34, L35, L36, L37, L37A, L38, L39, L41). Eleven (proteins L7, L10A, L11, L12, L13A, L23, L23A, L27A, L28, L29, and P0) resulted in mass changes that are consistent with N-terminal loss of methionine, acetylation, internal methylation, or hydroxylation. A loss of methionine without acetylation was found for protein L8 and L17. For nine proteins (L3, L4, L5, L7A, L10, L14, L19, L31, and L40), the molecular masses could not be determined. Proteins P1 and protein L3-like were not identified by the methods applied.  相似文献   

4.
目的鉴定女性生殖道乳杆菌种类及各种乳杆菌在阴道中的分布差异。方法通过扩增和测序乳酸杆菌16S rRNA序列中特异性区段(8f926r),并利用Vector NTI 8.0序列分析软件对各菌株的基因序列与标准菌株比对进行。结果 26株乳酸菌,L1株、L25株和L46株为乳酸杆菌属中的格氏乳酸杆菌(Lactobacillus gasseri);L2株、L5株、L6株、L7株、L8株、L11株、L13株、L15株、L19株、L20株、L24株、L26株、L28株、L29株、L31株、L32株、L33株、L34株、L35株、L36株、L40株与L45株均为乳酸杆菌属中的卷曲乳酸杆菌(Lactobacillus crispatus),而L21株未鉴定为乳酸球菌。结论女性阴道乳酸杆菌的优势菌种是卷曲乳杆菌、格氏乳杆菌。  相似文献   

5.
The proteins of the large subunit of rat liver ribosomes were separated into seven groups by stepwise elution from carboxymethylcellulose with LiCl at pH 6.5. Seventeen proteins (L4, L5, L7, L9, L11, L12, L13, L21, L22, L23, L26, L27, L30, L33, L35', L37, and L39) were isolated from three of the groups (B60, D60, G60) by ion exchange chromatography on carboxymethylcellulose and by filtration through Sephadex. The amount of protein obtained varied from 0.5 to 15 mg. Eight of the proteins (L9, L11, L13, L21, L22, L35', L37 and L39) had no detectable contamination; the impurities in the others were no greater than 9%. The molecular weight of the proteins was estimated by polyacrylamide gel electrophoresis in sodium dodecyl sulfate; the amino acid composition was determined.  相似文献   

6.
Escherichia coli and Saccharomyces cerevisiae ribosomal proteins were chemically iodinated with 125I by chloramine T under conditions in which the proteins were denatured. The labelled proteins were subsequently separated by two-dimensional gel electrophoresis with an excess of untreated ribosomal proteins from the same species. The iodination did not change the electrophoretic mobility of the proteins as shown by the pattern of spots in the stained gel slabs and their autoradiography. The 125I radioactivity incorporated in the proteins was estimated by cutting out the gel spots from the two-dimensional electrophoresis gel slabs. The highest content of 125I was found in the ribosomal proteins L2, L11, L13, L20/S12, S4 and S9 from E. coli, and L2/L3, L4/L6/S7, L5, L19/L20, L22/S17, L29/S27, L35/L37 and S14/S15 from S. cerevisiae. Comparisons between the electrophoretic patterns of E. coli and S. cerevisiae ribosomal proteins were carried out by coelectrophoresis of labelled and unlabelled proteins from both species. E. coli ribosomal proteins L5, L11, L20, S2, S3 and S15/S16 were found to overlap with L15, L11/L16, L36/L37, S3, S10 and S33 from S. cerevisiae, respectively. Similar coelectrophoresis of E. coli 125I-labelled proteins with unlabelled rat liver and wheat germ ribosomal proteins showed the former to overlap with proteins L1, L11, L14, L16, L19, L20 and the latter with L2, L5, L6, L15, L17 from E. coli.  相似文献   

7.
对丽盲蝽属 (丽盲蝽亚属 )Lygocoris (subg .Lygocoris)的中国种类作了修订。文中共包括 19个种 ,其中有 12新种 ,1个中国新纪录种 ,并包括 1项新等级的认定。即暗胝丽盲蝽L .(L .)calligersp .nov .(正模 :四川峨眉山九老洞 ) ,程氏丽盲蝽L .(L .)chengisp .nov .(正模 :四川峨眉山大乘寺 ) ,晕斑丽盲蝽L .(L .)diffusomaculatussp .nov .(正模 :甘肃榆中兴隆山 ) ,淡色丽盲蝽L .(L .)dilutussp .nov .(正模 :甘肃夏河县合作 ) ,锈褐丽盲蝽L .(L .) ferrugineussp .nov .(正模 :云南哀牢山 ) ,褐盾丽盲蝽L .(L .) fuscoscutel latus (Reuter ,190 6 )stat .nov .[由L .(L .)striicornisvar.fuscoscutellatus升为种级阶元 ],广西丽盲蝽L .(L .) guangxiensissp .nov .(正模 :广西龙胜 ) ,东亚丽盲蝽L .(L .)idoneus(Linnavuori,196 3) (中国新纪录种 ) ,完脊丽盲蝽L .(L .)integricarinatussp .nov .(甘肃榆中麻家寺 ) ,林氏丽盲蝽L .(L .)linnavuoriisp .nov .(云南哀牢山簸箕坝 ) ,长翅丽盲蝽L .(L .)longipennis (Reuter ,190 6 ) ,斑盾丽盲蝽L .(L .)maculis cutellatussp .nov .(四川理县刷经寺 ) ,原丽盲蝽L .(L .) pabulinus (Linnaeus ,176 1) ,红盾丽盲蝽L .(L .)rufiscutellatussp .nov .(甘  相似文献   

8.
Summary Ribosomal proteins L4, L5, L20 and L25 have been localized on the surface of the 50S ribosomal subunit of Escherichia coli by immuno-electron microscopy. The two 5S RNA binding proteins L5 and L25 were both located at the central protuberance extending towards its base, at the interface side of the 50S particle. L5 was localized on the side of the central protuberance that faces the L1 protuberance, whereas L25 was localized on the side that faces the L7/L12 stalk. Proteins L4 and L20 were both located at the back of the 50S subunit; L4 was located in the vicinity of proteins L23 and L29, and protein L20 was localized between proteins L17 and L10 and is thus located below the origin of the L7/L12 stalk.  相似文献   

9.
Summary The accessibility of each of the proteins on the 50S ribosomal subunit of Escherichia coli was investigated by establishing whether immunoglobulins (IgG), specific for each of the 34 proteins from the 50S subunit, were able to bind to the 50S subunit. The main criterion for accessibility was the formation of specific antibody-50S subunit complexes that could be detected by means of analytical ultracentrifugation.The proteins fell into two main groups. Immunoglobulins against proteins L1, L2, L3, L4, L5, L6, L7/L12, L8, L9, L10, L11, L14, L15, L16, L17, L18, L19, L20, L21, L22, L23, L25, L26, L27 and L30 gave large amounts of complex (20–100%) and, therefore, these proteins were considered to be accessible sible on the surface of the 50S ribosomal subunit. The antibodies against the remaining proteins L13, L24, L28, L29 and L31 to L34 produced small amounts of complexes (10–20%). Since their effects were unequivocably stronger than those obtained with IgG's from sera of non-immunized animals, the results indicate that these proteins are probably also accessible. Nonetheless, from the ultracentrifugation studies alone definite conclusions about the exposure of the latter group of proteins could not be drawn.  相似文献   

10.
Identification of all the protein components of the large subunit (39 S) of the mammalian mitochondrial ribosome has been achieved by carrying out proteolytic digestions of whole 39 S subunits followed by analysis of the resultant peptides by liquid chromatography and mass spectrometry. Peptide sequence information was used to search the human EST data bases and complete coding sequences were assembled. The human mitochondrial 39 S subunit has 48 distinct proteins. Twenty eight of these are homologs of the Escherichia coli 50 S ribosomal proteins L1, L2, L3, L4, L7/L12, L9, L10, L11, L13, L14, L15, L16, L17, L18, L19, L20, L21, L22, L23, L24, L27, L28, L30, L32, L33, L34, L35, and L36. Almost all of these proteins have homologs in Drosophila melanogaster, Caenorhabditis elegans, and Saccharomyces cerevisiae mitochondrial ribosomes. No mitochondrial homologs to prokaryotic ribosomal proteins L5, L6, L25, L29, and L31 could be found either in the peptides obtained or by analysis of the available data bases. The remaining 20 proteins present in the 39 S subunits are specific to mitochondrial ribosomes. Proteins in this group have no apparent homologs in bacterial, chloroplast, archaebacterial, or cytosolic ribosomes. All but two of the proteins has a clear homolog in D. melanogaster while all can be found in the genome of C. elegans. Ten of the 20 mitochondrial specific 39 S proteins have homologs in S. cerevisiae. Homologs of 2 of these new classes of ribosomal proteins could be identified in the Arabidopsis thaliana genome.  相似文献   

11.
The 50 S ribosomal subunits from Escherichia coli were modified by reaction with 2-iminothiolane under conditions in which 65 sulfhydryl groups, about 2/protein, were added per subunit. Earlier work showed that protein L7/L12 was modified more extensively than the average but that nearly all 50 S proteins contained sulfhydryl groups. Mild oxidation led to the formation of disulfide protein-protein cross-links. These were fractionated by urea gel electrophoresis and then analyzed by diagonal gel electrophoresis. Cross-linked complexes containing two, three, and possibly four copies of L7/L12 were evident. Cross-links between L7/L12 and other ribosomal proteins were also formed. These proteins were identified as L5, L6, L10, L11, and, in lower yield, L9, L14, and L17. The yields of cross-links to L5, L6, L10, and L11 were comparable to the most abundant cross-links formed. Similar experiments were performed with 70 S ribosomes. Protein L7/L12 in 70 S ribosomes was cross-linked to proteins L6, L10, and L11. The strong L7/L12-L5 cross-link found in 50 S subunits was absent in 70 S ribosomes. No cross-links between 30 S proteins and L7/L12 were observed.  相似文献   

12.
Karyotypes of 27 species in Leucadendron are analysed for the first time. New chromosome counts are reported for 15 species, with 2 n  = 26 occurring in all of them. Karyotype analysis indicated that chromosomes of Leucadendron taxa are small in size and have predominantly median to submedian centromeres. The mean sizes of somatic metaphase chromosomes ranged from 1.05 to 2.65 µm. Based on Stebbins' karyotype classification, 1A type was found in L. galpinii , L. muirii , L. orientale , L. platyspermum , L. rubrum , and L. salignum ; 2A type in L. conicum , L. flexuosum , L. laureolum , L. meridianum , L. salicifolium , L. stelligerum , and L. teretifolium ; and 2B type in L. argenteum , L. chamelaea , L. discolor , L. elimense , L. eucalyptifolium , L. floridum , L. gandogeri , L. linifolium , L. loeriense , L. macowanii , L. procerum , L. spissifolium , L. strobilinum , and L. tinctum . These types are the three most symmetrical karyotypes and are considered to be primitive.  © 2006 The Linnean Society of London, Botanical Journal of the Linnean Society , 2006, 151 , 387–394.  相似文献   

13.
Interactions between papillomavirus L1 and L2 capsid proteins   总被引:4,自引:0,他引:4       下载免费PDF全文
The human papillomavirus (HPV) capsid consists of 360 copies of the major capsid protein, L1, arranged as 72 pentamers on a T=7 icosahedral lattice, with substoichiometric amounts of the minor capsid protein, L2. In order to understand the arrangement of L2 within the HPV virion, we have defined and biochemically characterized a domain of L2 that interacts with L1 pentamers. We utilized an in vivo binding assay involving the coexpression of recombinant HPV type 11 (HPV11) L1 and HPV11 glutathione S-transferase (GST) L2 fusion proteins in Escherichia coli. In this system, L1 forms pentamers, GST=L2 associates with these pentamers, and L1+L2 complexes are subsequently isolated by using the GST tag on L2. The stoichiometry of L1:L2 in purified L1+L2 complexes was 5:1, indicating that a single molecule of L2 interacts with an L1 pentamer. Coexpression of HPV11 L1 with deletion mutants of HPV11 L2 defined an L1-binding domain contained within amino acids 396 to 439 near the carboxy terminus of L2. L2 proteins from eight different human and animal papillomavirus serotypes were tested for their ability to interact with HPV11 L1. This analysis targeted a hydrophobic region within the L1-binding domain of L2 as critical for L1 binding. Introduction of negative charges into this hydrophobic region by site-directed mutagenesis disrupted L1 binding. L1-L2 interactions were not significantly disrupted by treatment with high salt concentrations (2 M NaCl), weak detergents, and urea concentrations of up to 2 M, further indicating that L1 binding by this domain is mediated by strong hydrophobic interactions. L1+L2 protein complexes were able to form virus-like particles in vitro at pH 5.2 and also at pH 6.8, a pH that is nonpermissive for assembly of L1 protein alone. Thus, L1/L2 interactions are primarily hydrophobic, encompass a relatively short stretch of amino acids, and have significant effects upon in vitro assembly.  相似文献   

14.
Experiments were performed in order to determine the minimal requirement for the proteins L7/L12 in polyphenylalanine synthesis and elongation factor EF-G-dependent GTP hydrolysis. Via reconstitution, ribosomal particles were prepared containing variable amounts of L7/L12. The L7/L12 content of these particles was carefully determined by the use of 3H-labelled L7/L12 and by radioimmunoassay. The activity of the particles was determined as a function of the L7/L12 content. Our results show that only one dimer of L7/L12 is required for full activity in EF-G-dependent GTP hydrolysis. On the other hand, two L7/L12 dimers are required for polyphenylalanine synthesis. In addition, we have determined the relation between the number of L7/L12 stalks, as observed by electron microscopy, and the L7/L12 content of the 50 S particles. Our interpretation of these results is that each ribosomal particle possesses two L7/L12 binding sites, each site being involved in binding one dimer. Binding of L7/L12 dimer in one site gives rise to formation of the L7/L12 stalk, whereas binding in the other site has no effect on the number of visible stalks.  相似文献   

15.
We previously showed that an envelope A27L protein of intracellular mature virions (IMV) of vaccinia virus binds to cell surface heparan sulfate during virus infection. In the present study we identified another viral envelope protein, D8L, that binds to chondroitin sulfate on cells. Soluble D8L protein interferes with the adsorption of wild-type vaccinia virions to cells, indicating a role in virus entry. To explore the interaction of cell surface glycosaminoglycans and vaccinia virus, we generated mutant viruses from a control virus, WR32-7/Ind14K (A27L(+) D8L(+)) to be defective in expression of either the A27L or the D8L gene (A27L(+) D8L(-) or A27L(-) D8L(+)) or both (A27L(-) D8L(-)). The A27L(+) D8L(+) and A27L(-) D8L(+) mutants grew well in BSC40 cells, consistent with previous observations. However, the IMV titers of A27L(+) D8L(-) and A27L(-) D8L(-) viruses in BSC40 cells were reduced, reaching only 10% of the level for the control virus. The data suggested an important role for D8L protein in WR32-7/Ind14K virus growth in cell cultures. A27L protein, on the other hand, could not complement the functions of D8L protein. The low titers of the A27L(+) D8L(-) and A27L(-) D8L(-) mutant viruses were not due to defects in the morphogenesis of IMV, and the mutant virions demonstrated a brick shape similar to that of the control virions. Furthermore, the infectivities of the A27L(+) D8L(-) and A27L(-) D8L(-) mutant virions were 6 to 10% of that of the A27L(+) D8L(+) control virus. Virion binding assays revealed that A27L(+) D8L(-) and A27L(-) D8L(-) mutant virions bound less well to BSC40 cells, indicating that binding of viral D8L protein to cell surface chondroitin sulfate could be important for vaccinia virus entry.  相似文献   

16.
Summary Using p-nitrophenylcarbamyl-phenylananyl-tRNA (PNPC-Phe-tRNA) and N-Iodoacetyl-phenylalanyl-tRNA as affinity labels we have attempted to identify the components of the aminoacyl-tRNA binding sites located in the vicinity of the peptidyl transferase centre of the yeast ribosome. Both Phe-tRNA derivatives bind to the ribosomal A-site in the presence of 20 mM Mg++ ion concentration and can be translocated to the ribosomal P-site in the presence of elongation factor. After the labels have been allowed to react covalently with ribosomes they were found associated with the large ribosomal subunit. Proteins L36, L43, L42, L29, L2, L17/18, L19/20 and proteins L26, L38, L22/23, L7/9, L4/6, L36, L11, L43, L39 were labelled in samples treated with PNPC-Phe-tRNA and N-Iodoacetyl-Phe-tRNA respectively. In contrast, when only the components of the ribosomal P-site were analysed by reacting the treated particles with puromycin fewer spots were labelled, corresponding to proteins L36 and L19/20 using PNPC-Phe-tRNA and proteins L4/6, L36, and L43 using N-Iodoacetyl-Phe-tRNA.  相似文献   

17.
Abstract: Genome size determinations using propidium iodide flow cytometry were conducted in Lupinus anatolicus, L. pilosus, L. luteus, L. hispanicus ssp. hispanicus and L. hispanicus ssp. hispa-nicus × L. luteus (a complex hybridization product ofL. hispanicus ssp. hispanicus and L. luteus ). Using Glycine max "Ceresia" (1C = 1.134pg) and an accession of L. pilosus (1C = 0.649pg) as internal standards the following 1C values were obtained: L. anatolicus: 0.606 pg; L. pilosus: 0.620–0.678 pg; L. luteus: 1.173 pg; L. hispanicus: 1.043 pg; L. hispanicus ssp. hispanicus × L luteus: 1.036 pg. Lupinus anatolicus is a newly described taxon with smooth seeds whose genome is approximately as small as the smallest genomes measured in the related L. pilosus , a taxon with rough seeds. The genomes in the related smooth-seeded taxa L. luteus, L. hispanicus and L. hispanicus ssp. hispanicus × L. luteus are considerably larger. There is a 1.13-fold difference between L. luteus (crop) and L. hispanicus (wild). The genome size of L. hispanicus ssp. hispanicus × L. luteus , however, is not intermediate, it is close to L. hispanicus .  相似文献   

18.
The biogenesis of 30 S and 50 S ribosomal subunits in exponentially growing Escherichia coli has been studied by following the rate of appearance of pulse-labelled ribosomal proteins on mature subunits. Cells were pulse-labelled for two minutes and for three and a half minutes with radioactive leucine. Ribosomal proteins were extracted and purified by chromatography on carboxymethyl cellulose and analysed by bidimensional gel electrophoresis. All 30 S proteins and most of the 50 S proteins were thus prepared and their radioactivity counted: unequal labelling was obtained. 30 S and 50 S proteins were ordered according to increasing specific radioactivity at both time pulses. The incorporation was greater at three and a half minutes than at two minutes. No major difference in the order at the two labelling times was observed.Only two classes of proteins can be defined in the 30 S and the 50 S subunits, namely early and late proteins. In each class a gradual increase in the radioactivity is apparent from the poorly labelled to the highly labelled proteins. This suggests a definite order of addition.Early 30 S proteins: S17, S16, S15, S19, S18, S8, S4, S20, S10, S6, S9, S12, S7.Late 30 S proteins: S5, S3, S2, S14, S11, S13, S1, S21.Early 50 S proteins: L22, L20, L21, L4, L13, L16, L3, L23, L18, L24, L28, L17, L19, L29, L32, L5, L15, L2, L30, L27.Late 50 S proteins: L25, L11, L7, L12, L1, L9, L8, L10, L33, L14, L6.This order is discussed taking into account the pool size of the proteins measured in the same conditions of cell culture.  相似文献   

19.
石蒜属植物分支系统学分析   总被引:10,自引:0,他引:10  
邓传良  周坚 《植物研究》2005,25(4):393-399
基于37个形态学、解剖学、孢粉学和细胞学性状及解剖学性状之外的28个形态学、孢粉学和细胞学性状,分别对石蒜属进行分支系统学分析,试图建立石蒜属种间的系统发育关系。利用PAUP*软件分别构建了最大简约树(MP),所得树的拓扑结构是一致的。同时,基于解剖学9个性状,对石蒜、换锦花、忽地笑、江苏石蒜、长筒石蒜、乳白石蒜、夏水仙、红兰石蒜、安徽石蒜、短蕊石蒜、中国石蒜11个种进行系统发育树构建,其结果也是支持上述系统发育树的。系统发育树结构结果表明,石蒜属16种明显聚为两大类:石蒜、玫瑰石蒜、稻草石蒜和江苏石蒜;广西石蒜、红兰石蒜、换锦花、香石蒜、夏水仙、长筒石蒜、安徽石蒜、中国石蒜、忽地笑、乳白石蒜、短蕊石蒜和陕西石蒜。除换锦花、红兰石蒜及江苏石蒜系统发育位置不同之外,大类群的划分与RAPD指纹图谱基本一致。类群一均属于石蒜亚属(Lycoris亚属)。类群二又可以聚为两小类:广西石蒜、红兰石蒜、换锦花、香石蒜、夏水仙归为一类;长筒石蒜、安徽石蒜、中国石蒜、忽地笑、乳白石蒜、短蕊石蒜和陕西石蒜归为一类。前一子类群除广西石蒜外,都属于整齐花亚属(Symman thus亚属)。后一子类群除长筒石蒜与安徽石蒜外,均属于石蒜亚属(Lycoris亚属)。因此,花冠整齐与否是一个重要的分类特征,但作为石蒜属植物亚属的划分依据,没有得到本研究支持。而在本文中,雄蕊与花被片的位置关系可以作为大分类群划分依据,能否依此来对石蒜属植物亚属进行划分,仍需探讨。另外研究表明叶微形态特征在研究种间亲缘关系时,具有一定的作用。而在种间亲缘关系鉴定时,出叶期不应成为重要的依据。同时研究还表明中国石蒜与忽地笑具有非常近的亲缘关系,与形态学研究一致。  相似文献   

20.
The aim of this study was to evaluate the anesthesia induction and recovery times of sub-adult and post-larvae white shrimp (Litopenaeus vannamei) that were treated with eugenol and the essential oils (EOs) from Lippia alba and Aloysia triphylla. Oxidative stress parameters in the hemolymph of this species were also analyzed. The concentrations of eugenol, A. triphylla EO and L. alba EO recommended for anesthesia were 200, 300 and 750 μL L(-1) for sub-adults and 175, 300 and 500 μL L(-1) for post-larvae, respectively. The concentrations studied during the transport of sub-adults were between 20 and 50 μL L(-1) eugenol, 20-30 μL L(-1)A. triphylla EO and 50 μL L(-1)L. alba EO. For post-larvae, the optimal concentrations for transport were 20 μL L(-1) eugenol and between 20 and 50 μL L(-1)A. triphylla EO. The white shrimp sub-adults that were exposed to A. triphylla EO (20 μL L(-1)) showed increases in their total antioxidant capacities (150%), catalase (70%) and glutathione-S-transferase (615%) activity after 6 h. L. alba EO (50 μL L(-1)) and eugenol (20 μL L(-1)) also increased GST activity (1292 and 1315%) after 6 h, and eugenol (20 μL L(-1)) decreased the total antioxidant capacity (100%). Moreover, concentrations above 30 μL L(-1) for the EOs of A. triphylla and L. alba and 20 μL L(-1) eugenol were effective at inducing anesthesia and improving the antioxidant system against reactive oxygen species (ROS) after 6 h.  相似文献   

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