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Sample records for cycad cycas revoluta

  1. A plant class V chitinase from a cycad (Cycas revoluta): biochemical characterization, cDNA isolation, and posttranslational modification.

    Science.gov (United States)

    Taira, Toki; Hayashi, Hiroko; Tajiri, Yoshiko; Onaga, Shoko; Uechi, Gen-ichiro; Iwasaki, Hironori; Ohnuma, Takayuki; Fukamizo, Tamo

    2009-12-01

    Chitinase-A (CrChi-A) was purified from leaf rachises of Cycas revoluta by several steps of column chromatography. It was found to be a glycoprotein with a molecular mass of 40 kDa and an isoelectric point of 5.6. CrChi-A produced mainly (GlcNAc)(3) from the substrate (GlcNAc)(6) through a retaining mechanism. More interestingly, CrChi-A exhibited transglycosylation activity, which has not been observed in plant chitinases investigated so far. A cDNA encoding CrChi-A was cloned by rapid amplification of cDNA ends and polymerase chain reaction procedures. It consisted of 1399 nucleotides and encoded an open reading frame of 387-amino-acid residues. Sequence analysis indicated that CrChi-A belongs to the group of plant class V chitinases. From peptide mapping and mass spectrometry of the native and recombinant enzyme, we found that an N-terminal signal peptide and a C-terminal extension were removed from the precursor (M1-A387) to produce a mature N-glycosylated protein (Q24-G370). This is the first report on a plant chitinase with transglycosylation activity and posttranslational modification of a plant class V chitinase.

  2. Purification, characterization, and sequencing of antimicrobial peptides, Cy-AMP1, Cy-AMP2, and Cy-AMP3, from the Cycad (Cycas revoluta) seeds.

    Science.gov (United States)

    Yokoyama, Seiya; Kato, Kouji; Koba, Atsuko; Minami, Yuji; Watanabe, Keiichi; Yagi, Fumio

    2008-12-01

    Novel antimicrobial peptides (AMP), designated Cy-AMP1, Cy-AMP2, and Cy-AMP3, were purified from seeds of the cycad (Cycas revoluta) by a CM cellulofine column, ion-exchange HPLC on SP COSMOGEL, and reverse-phase HPLC. They had molecular masses of 4583.2 Da, 4568.9 Da and 9275.8 Da, respectively, by MALDI-TOF MS analysis. Half of the amino acid residues of Cy-AMP1 and Cy-AMP2 were cysteine, glycine and proline, and their sequences were similar. The sequence of Cy-AMP3 showed high homology to various lipid transfer proteins. For Cy-AMP1 and Cy-AMP2, the concentrations of peptides required for 50% inhibition (IC(50)) of the growth of plant pathogenic fungi, Gram-positive and Gram-negative bacteria were 7.0-8.9 microg/ml. The Cy-AMP3 had weak antimicrobial activity. The structural and antimicrobial characteristics of Cy-AMP1 and Cy-AMP2 indicated that they are a novel type of antimicrobial peptide belonging to a plant defensin family.

  3. Transglycosylation reaction catalyzed by a class V chitinase from cycad, Cycas revoluta: a study involving site-directed mutagenesis, HPLC, and real-time ESI-MS.

    Science.gov (United States)

    Taira, Toki; Fujiwara, Maho; Dennhart, Nicole; Hayashi, Hiroko; Onaga, Shoko; Ohnuma, Takayuki; Letzel, Thomas; Sakuda, Shohei; Fukamizo, Tamo

    2010-04-01

    Class V chitinase from cycad, Cycas revoluta, (CrChi-A) is the first plant chitinase that has been found to possess transglycosylation activity. To identify the structural determinants that bring about transglycosylation activity, we mutated two aromatic residues, Phe166 and Trp197, which are likely located in the acceptor binding site, and the mutated enzymes (F166A, W197A) were characterized. When the time-courses of the enzymatic reaction toward chitin oligosaccharides were monitored by HPLC, the specific activity was decreased to about 5-10% of that of the wild type and the amounts of transglycosylation products were significantly reduced by the individual mutations. From comparison between the reaction time-courses obtained by HPLC and real-time ESI-MS, we found that the transglycosylation reaction takes place under the conditions used for HPLC but not under the ESI-MS conditions. The higher substrate concentration (5 mM) used for the HPLC determination is likely to bring about chitinase-catalyzed transglycosylation. Kinetic analysis of the time-courses obtained by HPLC indicated that the sugar residue affinity of +1 subsite was strongly reduced in both mutated enzymes, as compared with that of the wild type. The IC(50) value for the inhibitor allosamidin determined by real-time ESI-MS was not significantly affected by the individual mutations, indicating that the state of the allosamidin binding site (from -3 to -1 subsites) was not changed in the mutated enzymes. We concluded that the aromatic side chains of Phe166 and Trp197 in CrChi-A participate in the transglycosylation acceptor binding, thus controlling the transglycosylation activity of the enzyme.

  4. Cloning and expression of a mannose-binding jacalin-related lectin from leaves of Japanese cycad (Cycas revoluta Thunb.).

    Science.gov (United States)

    Haraguchi, Tomokazu; Nomura, Keiichi; Yagi, Fumio

    2006-09-01

    Cycad leaf lectin (CRLL), a mannose-recognizing jacalin-related lectin (mJRL), was first cloned as a gymnosperm lectin and expressed. The cDNA sequence of CRLL (DDBJ, accession no. AB198328), coding 291 amino acid residues, has a tandem repeat of about 150 amino acids divided into N- and C-terminal domains as Japanese chestnut mJRL. Sequence alignment showed deletion and insertion of the sequence, and its putative carbohydrate-binding sites showed some differences from other JRLs. PCR analysis showed that this lectin was expressed in the cycad leaf but not in the root or seed. Recombinant CRLL (rCRLL) was expressed in Escherichia coli and purified by affinity chromatography after refolding procedures. Properties of active rCRLL appeared to be almost the same as those of native CRLL.

  5. 苏铁珊瑚状根及根周围土壤中蓝细菌的PCR指纹图谱%PCR fingerprintings of cyanobacteria isolated from coralloid roots of Cycads(Cycas revoluta)and their surrounding soil

    Institute of Scientific and Technical Information of China (English)

    陈彬; 宋铁英; 郑伟文

    2004-01-01

    以福建苏铁(Cycas revoluta)珊瑚状根及根周围土壤的蓝细菌分离物的悬浮液作为PCR反应的模板,用引物STRRmod、STRRspecial和Hip TG对分离物进行PCR扩增,比较其指纹图谱.结果表明,苏铁珊瑚状根内蓝细菌的指纹图谱不同于其周围土壤中蓝细菌的指纹图谱;也证实了同一地方不同株苏铁根周围的土壤蓝细菌具有多态性,苏铁珊瑚状根的不同分支的蓝细菌也具有多态性.

  6. Simplified Regeneration Protocol for Cycas revoluta Thunb. Mature Zygotic Embryos

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    Rohangiz NADERI

    2015-03-01

    Full Text Available Mature zygotic embryos of Cycas revoluta Thunb. were used as explants to investigate direct and indirect organogenesis. Explants were incubated on half-strength Murashige and Skoog (½ MS basal medium supplemented with various plant growth regulators, singly or in combination (all at 0.5 mg l-1: 6-benzyladenine (BA, kinetin (Kin, 2,4-dichlorophenoxyacetic acid (2,4-D, Kin×2,4-D, BA×Kin and BA×2,4-D. Cultures were placed at a low light intensity (4 µmol m-2 s-1 PPFD. Adventitious shoot regeneration was observed in the presence of 0.5 mg l-1BA after 35 days. The highest number of direct and indirect shoots per zygotic embryo was 3.67 and 29.67, respectively. Roots were induced on indirect shoots by continuous culture on rooting medium (½ MS,‏ 0.1 mg l-1 1-naphthaleneacetic acid and hardened successfully in perlite. Each rooted plantlet with pinnate leaves and a primary tap root was individually isolated and acclimatized 185 days after the beginning of culture, with a 10% success rate.

  7. Preliminary Study on Abnormal Morphological Characters ofCycas revoluta%苏铁Cycas revoluta两种特异形态特征

    Institute of Scientific and Technical Information of China (English)

    潘爱芳

    2016-01-01

    Two kinds of morphological anomalies inCycas revoluta were observed in Fuzhou, Fujian Province. The first was that a sucking bud seedling had grown 5 pieces of abnormal leaflets, one piece with a bifurcated midrib was longer than normal leaflets, and another had a double-pieced base. And the second was that a male cone had a rosette tip, as if there were a female cone on its top. These kinds of anomaly would provide some new basic data for cycad systematics and evolution.%在开展苏铁Cycas revoluta形态特征观测中,发现一株苏铁根蘖苗有5片羽片生长异常,其中一片比其他正常羽片长且中脉出现分叉(即一羽多脉现象),另外4片基部两两贴生。另一株苏铁的小孢子叶球生长奇特,其顶部为莲座状,形似大孢子叶球。这两种异常现象为苏铁类植物的系统分类与演化研究提供了新资料。

  8. Relative seed and fruit toxicity of the Australian cycads Macrozamia miquelii and Cycas ophiolitica: further evidence for a megafaunal seed dispersal syndrome in cycads, and its possible antiquity.

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    Hall, J A; Walter, G H

    2014-08-01

    An apparent contradiction in the ecology of cycad plants is that their seeds are known to be highly poisonous, and yet they seem well adapted for seed dispersal by animals, as shown by their visually conspicuous seed cones and large seeds presented within a brightly colored fleshy "fruit" of sarcotesta. We tested if this sarcotesta could function as a reward for cycad seed dispersal fauna, by establishing if the toxic compound cycasin, known from the seeds, is absent from the sarcotesta. The Australian cycads Macrozamia miquelii and Cycas ophiolitica were tested (N = 10 individuals per species) using gas chromatography / mass spectrometry. Cycasin was detected at 0.34 % (fresh weight) in seed endosperm of M. miquelii and 0.28 % (fresh weight) in seed endosperm of C. ophiolitica. Cycasin was absent from the sarcotesta of the same propagules (none detected in the case of M. miquelii, and trace quantities detected in sarcotesta of only four of the ten C. ophiolitica propagules). This laboratory finding was supported by field observations of native animals eating the sarcotesta of these cycads but discarding the toxic seed intact. These results suggest cycads are adapted for dispersal fauna capable of swallowing the large, heavy propagules whole, digesting the non-toxic sarcotesta flesh internally, and then voiding the toxic seed intact. Megafauna species such as extant emus or cassowaries, or extinct Pleistocene megafauna such as Genyornis, are plausible candidates for such dispersal. Cycads are an ancient lineage, and the possible antiquity of their megafaunal seed dispersal adaptations are discussed.

  9. Nuclear ribosomal ITS functional paralogs resolve the phylogenetic relationships of a late-Miocene radiation cycad Cycas (Cycadaceae.

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    Long-Qian Xiao

    Full Text Available Cycas is the most widespread and diverse genus among the ancient cycads, but the extant species could be the product of late Miocene rapid radiations. Taxonomic treatments to date for this genus are quite controversial, which makes it difficult to elucidate its evolutionary history. We cloned 161 genomic ITS sequences from 31 species representing all sections of Cycas. The divergent ITS paralogs were examined within each species and identified as putative pseudogenes, recombinants and functional paralogs. Functional paralogs were used to reconstruct phylogenetic relationships with pseudogene sequences as molecular outgroups, since an unambiguous ITS sequence alignment with their closest relatives, the Zamiaceae, is unachievable. A fully resolved and highly supported tree topology was obtained at the section level, with two major clades including six minor clades. The results fully supported the classification scheme proposed by Hill (2004 at the section level, with the minor clades representing his six sections. The two major clades could be recognised as two subgenera. The obtained pattern of phylogenetic relationships, combined with the different seed dispersal capabilities and paleogeography, allowed us to propose a late Miocene rapid radiation of Cycas that might have been promoted by vicariant events associated with the complex topography and orogeny of South China and adjacent regions. In contrast, transoceanic dispersals might have played an important role in the rapid diversification of sect. Cycas, whose members have evolved a spongy layer in their seeds aiding water dispersals.

  10. Nuclear ribosomal ITS functional paralogs resolve the phylogenetic relationships of a late-Miocene radiation cycad Cycas (Cycadaceae).

    Science.gov (United States)

    Xiao, Long-Qian; Möller, Michael

    2015-01-01

    Cycas is the most widespread and diverse genus among the ancient cycads, but the extant species could be the product of late Miocene rapid radiations. Taxonomic treatments to date for this genus are quite controversial, which makes it difficult to elucidate its evolutionary history. We cloned 161 genomic ITS sequences from 31 species representing all sections of Cycas. The divergent ITS paralogs were examined within each species and identified as putative pseudogenes, recombinants and functional paralogs. Functional paralogs were used to reconstruct phylogenetic relationships with pseudogene sequences as molecular outgroups, since an unambiguous ITS sequence alignment with their closest relatives, the Zamiaceae, is unachievable. A fully resolved and highly supported tree topology was obtained at the section level, with two major clades including six minor clades. The results fully supported the classification scheme proposed by Hill (2004) at the section level, with the minor clades representing his six sections. The two major clades could be recognised as two subgenera. The obtained pattern of phylogenetic relationships, combined with the different seed dispersal capabilities and paleogeography, allowed us to propose a late Miocene rapid radiation of Cycas that might have been promoted by vicariant events associated with the complex topography and orogeny of South China and adjacent regions. In contrast, transoceanic dispersals might have played an important role in the rapid diversification of sect. Cycas, whose members have evolved a spongy layer in their seeds aiding water dispersals.

  11. 蓝细菌与福建苏铁(Cycad revoluta)的侵染性重组的研究%Infection association study by reconstituting Cycad revolute and cyanobacteria

    Institute of Scientific and Technical Information of China (English)

    陈彬; 郑斯平; 郑伟文

    2007-01-01

    将苏铁珊瑚状根及根周围的土壤中分离的蓝细菌分离物与福建苏铁(Cycas revoluta)在实验室条件下进行重组.通过比较重组前后蓝细菌分离物的STRR指纹图谱和16S rRNA的序列得蓝细菌分离物RZHA4能重新侵染苏铁的珊瑚状根.通过NCBI比对,蓝细菌分离物RZHA4的16S rRNA序列与蓝细菌Nostocaceae IL13-1的相似性为99%.

  12. When North and South don't mix: genetic connectivity of a recently endangered oceanic cycad, Cycas micronesica, in Guam using EST-microsatellites.

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    Cibrián-Jaramillo, Angélica; Daly, A C; Brenner, E; Desalle, R; Marler, T E

    2010-06-01

    Subject to environmental changes and recurrent isolation in the last ca. 250 Ma, cycads are often described as relicts of a previously common lineage, with populations characterized by low genetic variation and restricted gene flow. We found that on the island of Guam, the endemic Cycas micronesica has most of the genetic variation of 14 EST-microsatellites distributed within each of 18 genetic populations, from 24 original sampling sites. There were high levels of genetic variation in terms of total number of alleles and private alleles, and moderate levels of inbreeding. Restricted but ongoing gene flow among populations within Guam reveals a genetic mosaic, probably more typical of cycads than previously assumed. Contiguous cycad populations in the north of Guam had higher self-recruitment rates compared to fragmented populations in the south, with no substantial connection between them except for one population. Guam's genetic mosaic may be explained by the influence of forest continuity, seed size, edaphic differences, and human transport of cycads. Also important are the extent of synchrony among flushes of reproductive female seed-bearing sporophylls and restricted pollen movement by an obligate mutualist and generalist insects. An NADH EST-locus under positive selection may reflect pressure from edaphic differences across Guam. This and three other loci are ideal candidates for ecological genomic studies. Given this species' vulnerability due to the recent introduction of the cycad aulacaspis scale, we also identify priority populations for ex situ conservation, and provide a genetic baseline for understanding the effects of invasive species on cycads in the Western Pacific, and islands in general.

  13. "云南苏铁"考%Notes on Yunnan Cycad (Cycas siamensis Miquel)

    Institute of Scientific and Technical Information of China (English)

    王定跃

    2000-01-01

    "云南苏铁"(Cycas siamensis Mi quel)长期被认为产于云南西部,并被广泛引用.有些学者把产自云南东南部,甚至广西西部与四川攀枝花地区的苏铁也归于该种.笔者研究表明,C.siamensis Miquel在我国并无分布,应恢复其中文名暹罗苏铁,而"云南苏铁"实际上是一个长期误定,又广泛引用而应予以废弃的苏铁名称.

  14. Asymmetric Introgression in the Horticultural Living Fossil Cycas Sect. Asiorientales Using a Genome-Wide Scanning Approach

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    Shong Huang

    2013-04-01

    Full Text Available The Asian cycads are mostly allopatric, distributed in small population sizes. Hybridization between allopatric species provides clues in determining the mechanism of species divergence. Horticultural introduction provides the chance of interspecific gene flow between allopatric species. Two allopatrically eastern Asian Cycas sect. Asiorientales species, C. revoluta and C. taitungensis, which are widely distributed in Ryukyus and Fujian Province and endemic to Taiwan, respectively, were planted in eastern Taiwan for horticultural reason. Higher degrees of genetic admixture in cultivated samples than wild populations in both cycad species were detected based on multilocus scans by neutral AFLP markers. Furthermore, bidirectional but asymmetric introgression by horticultural introduction of C. revoluta is evidenced by the reanalyses of species associated loci, which are assumed to be diverged after species divergence. Partial loci introgressed from native cycad to the invaders were also detected at the loci of strong species association. Consistent results tested by all neutral loci, and the species-associated loci, specify the recent introgression from the paradox of sharing of ancestral polymorphisms. Phenomenon of introgression of cultivated cycads implies niche conservation among two geographic-isolated cycads, even though the habitats of the extant wild populations of two species are distinct.

  15. Paraphyly of organelle DNAs in Cycas Sect. Asiorientales due to ancient ancestral polymorphisms

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    Hsu Tsai-Wen

    2009-07-01

    Full Text Available Abstract Background This study addresses the apportionment of genetic diversity between Cycas revoluta and C. taitungensis, species that constitute the section Asiorientales and represent a unique, basal lineage of the Laurasian genus Cycas. Fossil evidence indicates divergence of the section from the rest of Cycas at least 30 million years ago. Geographically, C. taitungensis is limited to Taiwan whereas C. revoluta is found in the Ryukyu Archipelago and on mainland China. Results The phylogenies of ribosomal ITS region of mtDNA and the intergenic spacer between atpB and rbcL genes of cpDNA were reconstructed. Phylogenetic analyses revealed paraphyly of both loci in the two species and also in the section Asiorientales. The lack of reciprocal monophyly between these long isolated sections is likely due to persistent shared ancestral polymorphisms. Molecular dating estimated that mt- and cp DNA lineages coalesced to the most recent common ancestors (TMRCA about 327 (mt and 204 MYA (cp, corresponding with the divergence of cycad sections in the Mesozoic. Conclusion Fates of newly derived mutations of cycads follow Klopfstein et al.'s surfing model where the majority of new mutations do not spread geographically and remain at low frequencies or are eventually lost by genetic drift. Only successful 'surfing mutations' reach very high frequencies and occupy a large portion of a species range. These mutations exist as dominant cytotypes across populations and species. Geographical subdivision is lacking in both species, even though recurrent gene flow by both pollen and seed is severely limited. In total, the contrasting levels between historical and ongoing gene flow, large population sizes, a long lifespan, and slow mutation rates in both organelle DNAs have all likely contributed to the unusually long duration of paraphyly in cycads.

  16. Stable oil bodies sheltered by a unique caleosin in cycad megagametophytes.

    Science.gov (United States)

    Jiang, Pei-Luen; Chen, Jeff C F; Chiu, Shau-Ting; Tzen, Jason T C

    2009-01-01

    Stable oil bodies of smaller sizes and higher thermostability were isolated from mature cycad (Cycas revoluta) megagametophytes compared with those isolated from sesame seeds. Immunological cross-recognition revealed that cycad oil bodies contained a major protein of 27 kDa, tentatively identified as caleosin, while oleosin, the well-known structural protein, was apparently absent. Mass spectrometric analysis showed that the putative cycad caleosin possessed a tryptic fragment of 15 residues matching to that of a theoretical moss caleosin. A complete cDNA fragment encoding this putative caleosin was obtained by PCR cloning using a primer designed according to the tryptic peptide and another one designed according to a highly conservative region among diverse caleosins. The identification of this clone was subsequently confirmed by immunodetection and MALDI-MS analyses of its recombinant fusion protein over-expressed in Escherichia coli and the native form from cycad oil bodies. Stable artificial oil bodies were successfully constituted with triacylglycerol, phospholipid and the recombinant fusion protein containing the cycad caleosin. These results suggest that stable oil bodies in cycad megagametophytes are mainly sheltered by a unique structural protein caleosin.

  17. Azoxyglycoside content and beta-glycosidase activities in leaves of various cycads.

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    Yagi, Fumio

    2004-12-01

    Azoxyglycoside contents in leaves of 32 cycad species belonging to 10 cycad genera and the seeds of 4 Encephalartos species were analyzed by HPLC with a YMC-PA03 amide column. Azoxyglycosides were detected in mature leaves of 14 cycad species including 2 Bowenia, 2 Lepidozamia, 1 Microcycas, and 1 Stangeria species, but not in mature leaves of 18 other cycad species; 2 of 3 Ceratozamia, 1 of 3 Cycas, 3 of 3 Dioon, 10 of 11 Encephalartos, 1 of 3 Macrozamia and 1 of 3 Zamia species analyzed. The ratios of beta-glycosidase activity toward cycasin and macrozamin in extracts from the leaves of 9 species belonging to 9 genera were measured. The hydrolysis of cycasin was higher in the leaf extracts of Cycas revoluta, Bowenia spectabilis, Stangeria eriopus and Ceratozamia mexicana, whereas in Lepidozamia hopei, the hydrolysis levels of cycasin and macrozamin were similar. On the other hand, activity toward macrozamin was higher in Dioon edule, Encephalartos villosus, Macrozamia miquelii and Zamia fischeri. The hydrolytic activities in most species were estimated to be sufficient for the release of methylazoxymethanol in leaves analogous to the cyanogenesis of cyanogenic plants. Therefore, hydrolysis of azoxyglycosides by endogenous glycosidase in leaves seems to occur by accidental injury of leaves. However, in M. miquelii leaf extract, hydrolytic activity toward macrozamin was high and the activity toward cycasin was very low, though only cycasin was found in the leaves of this species.

  18. LC-MS/MS determination of the isomeric neurotoxins BMAA (beta-N-methylamino-L-alanine) and DAB (2,4-diaminobutyric acid) in cyanobacteria and seeds of Cycas revoluta and Lathyrus latifolius.

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    Krüger, Thomas; Mönch, Bettina; Oppenhäuser, Steven; Luckas, Bernd

    2010-01-01

    Since diverse taxa of cyanobacteria has been linked to biosynthesis of BMAA, a controversy has arisen about the detection of neurotoxic amino acids in cyanobacteria. In this context, a novel LC-MS/MS method was developed for the unambiguous determination of beta-N-methylamino-L-alanine (BMAA) and 2,4-diaminobutyric acid (DAB) in cyanobacteria and selected plant seeds. Both neurotoxic and non-proteinogenic amino acids were analyzed without derivatization considering the total concentration of the free and protein-bound form. The investigation of overall 62 cyanobacterial samples of worldwide origin by application of this method revealed the absence of BMAA, whereas seeds of Cycas revoluta contained 6.96 microg g(-1) of free BMAA. In contrast, the isomer DAB was confirmed in 16 cyanobacterial samples in concentrations of 0.07-0.83 microg g(-1),whereof one sample is distributed as nutritional supplement. In addition, seeds of Lathyrus latifolius contained 4.21 microg g(-1) of free DAB. Limits of detection were for BMAAdisadvantages of derivatization-based methods to be discussed.

  19. 苏铁(Cycasrevoluta)种子核仁中氨基酸成分分析%Analysis on nucleolus amino acid composition of Cycas revoluta seeds

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    黄超群; 莫昭展

    2013-01-01

    In this paper, the amino acids in nucleolus of Cycas revolute were analyzed. There were 17 types of amino acids in nucleolus. According to the analysis results, proportions of Total Amino Acid(TAA) and Essential Amino Acid(EAA) were respectively 8.16% and 2.91%, which was smaller than proportion of standard protein. However, Amino acids for medical purposes and flavor amino acid accounted separately for 68% and 27.7% of TAA, which had important significance for development and utilization of Cycas revolute seeds.%对苏铁种子核仁中氨基酸成分进行分析,苏铁种子中含有17种氨基酸,其中总氨基酸(TAA)和必需氨基酸(EAA)含量分别为8.16和2.91.其两种氨基酸的比例与标准蛋白质存在一定的差距,但是苏铁种子药用氨基酸和鲜味氨基酸的含量分别为68%和27.7%,对苏铁种子的开发利用具有重要意义.

  20. 苏铁播种育苗技术研究%Research on technology of sowing and cultivating seedling of cycad ( Cycas revoluta )

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    傅瑞树

    2002-01-01

    通过研究不同浓度ABT3号生根粉、不同浸种时间、不同播种时间和地膜覆盖对苏铁种子发芽、成苗及幼苗生长的影响,不同透光度和叶面肥对出苗速度、发芽率、叶绿素含量的影响结果表明,0.02μg/kg浓度生根粉处理最为有效,使发芽率和成苗率达60%以上,与其他处理相比差异明显;而浸种时间效应较弱,播种时间效应明显,4月1 3日播种最佳,出土所需时间最短,与其他处理相比差异显著.覆盖地膜能显著提高苏铁种子的发芽率和成苗率,并使出土时间明显缩短;透光度对叶片的生长和叶绿素含量影响明显,60%的透光度最佳,喷施叶面肥能显著促进苏铁叶片生长,提高叶绿素含量.

  1. Cycad Aulacaspis Scale, a Newly Introduced Insect Pest in Indonesia

    OpenAIRE

    2012-01-01

    Cycad aulacaspis scale (Aulacaspis yasumatsui Takagi (Hemiptera: Diaspididae)) is native to Thailand and Vietnam. Since the early 1990s it has been spreading around the world due to the trade in cycad plants for ornamental use. Infestation by this scale can kill cycads in only a few months. Its accidental introduction to Florida endangered the ornamental cycad-growing industry; and in Guam and Taiwan, endemic cycads (Cycas micronesica and C. taitungensis, respectively) are currently threatene...

  2. Taxonomy and conservation of Philippine Cycads

    NARCIS (Netherlands)

    Madulid, D.A.; Agoo, E.M.G.

    2009-01-01

    Six species of cycads are recorded in the Philippines, three of which are endemic. The different species of cycads can be recognized by the characters of the microsporophylls, megasporophylls, and seeds. The current conservation status of the different species of Cycas is assessed and categorized us

  3. Evolutionary developmental biology in cycad phenology.

    Science.gov (United States)

    Gorelick, Root; Marler, Thomas E

    2012-05-01

    We recently described lack of phenotypic plasticity in reproductive organ development and substantial plasticity in vegetative organ development for the cycad Cycas micronesica. Is there an evo-devo explanation for the disparity in phenotypic plasticity of vegetative vs. reproductive organs? Despite modularity, might evolution of cycad phenology be controlled more by drift than selection?

  4. Evolutionary developmental biology in cycad phenology

    OpenAIRE

    2012-01-01

    We recently described lack of phenotypic plasticity in reproductive organ development and substantial plasticity in vegetative organ development for the cycad Cycas micronesica. Is there an evo-devo explanation for the disparity in phenotypic plasticity of vegetative vs. reproductive organs? Despite modularity, might evolution of cycad phenology be controlled more by drift than selection?

  5. The chitin-binding capability of Cy-AMP1 from cycad is essential to antifungal activity.

    Science.gov (United States)

    Yokoyama, Seiya; Iida, Yuto; Kawasaki, Yousuke; Minami, Yuji; Watanabe, Keiichi; Yagi, Fumio

    2009-07-01

    Antimicrobial peptides are important components of the host innate immune responses by exerting broad-spectrum microbicidal activity against pathogenic microbes. Cy-AMP1 found in the cycad (Cycas revoluta) seeds has chitin-binding ability, and the chitin-binding domain was conserved in knottin-type and hevein-type antimicrobial peptides. The recombinant Cy-AMP1 was expressed in Escherichia coli and purified to study the role of chitin-binding domain. The mutants of Cy-AMP1 lost chitin-binding ability completely, and its antifungal activity was markedly decreased in comparison with native Cy-AMP1. However, the antimicrobial activities of the mutant peptides are nearly identical to that of native one. It was suggested that the chitin-binding domain plays an essential role in antifungal, but not antimicrobial, activity of Cy-AMP1.

  6. The distribution, diversity, and conservation status of Cycas in China.

    Science.gov (United States)

    Zheng, Ying; Liu, Jian; Feng, Xiuyan; Gong, Xun

    2017-05-01

    As ancient gymnosperm and woody plants, cycads have survived through dramatic tectonic activities, climate fluctuation, and environmental variations making them of great significance in studying the origin and evolution of flora biodiversity. However, they are among the most threatened plant groups in the world. The principal aim of this review is to outline the distribution, diversity, and conservation status of Cycas in China and provide suggestions for conservation practices. In this review, we describe the taxonomy, distribution, and conservation status of Cycas in China. By comparing Chinese Cycas species with its relatives worldwide, we then discuss the current genetic diversity, genetic differentiation of Cycas, and try to disentangle the potential effects of Quaternary climate changes and topographical events on Cycas. We review conservation practices from both researchers and practitioners for these rare and endangered species. High genetic diversity at the species level and strong genetic differentiation within Cycas have been observed. Most Cycas species in southwest China have experienced population retreats in contrast to the coastal Cycas's expansion during the Quaternary glaciation. Additionally, human activities and habitat fragmentation have pushed these endangered taxa to the brink of extinction. Although numerous efforts have been made to mitigate threats to Cycas survival, implementation and compliance monitoring in protection zones are currently inadequate. We outline six proposals to strengthen conservation measures for Cycas in China and anticipate that these measures will provide guidelines for further research on population genetics as well as conservation biology of not only cycads but also other endangered species worldwide.

  7. Evidence for long isolation among populations of a pacific cycad: genetic diversity and differentiation in Cycas seemannii A.Br. (Cycadaceae).

    Science.gov (United States)

    Keppel, G; Lee, S-W; Hodgskiss, P D

    2002-01-01

    The genetic structure of Cycas seemannii A.Br. (Cycadaceae), sampled throughout its range in Vanuatu, New Caledonia, Fiji, and Tonga, was studied using starch-gel electrophoresis. Twenty enzyme loci in 13 enzyme systems were examined. Low genetic diversity within populations (A = 1.2, P = 21.3, Ho = 0.047, and He = 0.057) and a high degree of differentiation among populations (F(ST) = 0.594) were found. This, together with low gene flow estimates, suggests genetic drift by isolation to have been most critical to the current genetic structure of the species. Inbreeding may occur to some extent (F(IS) = 0.165). The decline in abundance of C. seemannii, coupled with the low level of genetic diversity, suggest that conservation strategies are urgently needed.

  8. Rethinking cycad metabolite research.

    Science.gov (United States)

    Snyder, Laura R; Marler, Thomas E

    2011-01-01

    Cycads are among the most ancient of extant Spermatophytes, and are known for their numerous pharmacologically active compounds. One compound in particular, β-methylamino-L-alanine (BMAA), has been implicated as the cause of amyotrophic lateral sclerosis/Parkinson dementia complex (ALS/PDC) on Guam. Previous studies allege that BMAA is produced exclusively by cyanobacteria, and is transferred to cycads through the symbiotic relationship between these cyanobacteria and the roots of cycads. We recently published data showing that Cycas micronesica seedlings grown without endophytic cyanobacteria do in fact increase in BMAA, invalidating the foundation of the BMAA hypothesis. We use this example to suggest that the frenzy centered on BMAA and other single putative toxins has hindered progress. The long list of cycad-specific compounds may have important roles in signaling or communication, but these possibilities have been neglected during decades of attempts to force single metabolites into a supposed anti-herbivory function. We propose that an unbiased, comprehensive approach may be a more appropriate means of proceeding with cycad biochemistry research.

  9. Preservation of cycad and Ginkgo pollen

    Science.gov (United States)

    Frederiksen, N.O.

    1978-01-01

    Pollen grains of Ginkgo, Cycas, and Encephalartos were chemically treated together with pollen of Quercus, Alnus, and Pinus, the latter three genera being used as standards. The experiments showed that: (1) boiling the pollen for 8-10 hours in 10% KOH had little if any effect on any of the grains; (2) lengthy acetolysis treatment produced some degradation or corrosion, particularly in Ginkgo and Cycas, but the grains of even these genera remained easily recognizable; (3) oxidation with KMnO4 followed by H2O2 showed that pollen of Ginkgo, Cycas, and Encephalartos remains better preserved than that of Quercus and Alnus, and although Ginkgo and Encephalartos probably are slightly less resistant to oxidation than Pinus, no great differences exists between these monosulcate types and Pinus. Thus the experiments show that, at least for sediments low in bacteria, cycad and Ginkgo pollen should be well represented in the fossil record as far as their preservational capabilities are concerned. ?? 1978.

  10. Cycad Aulacaspis Scale, a Newly Introduced Insect Pest in Indonesia

    Directory of Open Access Journals (Sweden)

    NATALIA VON ELLENRIEDER

    2012-09-01

    Full Text Available Cycad aulacaspis scale (Aulacaspis yasumatsui Takagi (Hemiptera: Diaspididae is native to Thailand and Vietnam. Since the early 1990s it has been spreading around the world due to the trade in cycad plants for ornamental use. Infestation by this scale can kill cycads in only a few months. Its accidental introduction to Florida endangered the ornamental cycad-growing industry; and in Guam and Taiwan, endemic cycads (Cycas micronesica and C. taitungensis, respectively are currently threatened with extinction by cycad aulacaspis scale. In November 2011, an introduced scale was discovered damaging cycads in the Bogor Botanic Garden. Samples from Bogor were taken for identification of the scale, and the material was kept for some time to rear out any insect parasitoids that were present. Both the scale insects and parasitoids were prepared on microscope slides and studied microscopically for authoritative identification. The scale was confirmed as A. yasumatsui. The parasitoid Arrhenophagus chionaspidis Aurivillius (Hymenoptera: Encyrtidae and the hyperparasitoid Signiphora bifasciata Ashmead (Hymenoptera: Signiphoridae were identified from the samples. Unless immediate remedial measures are taken, several endemic species of cycad in Indonesia may be endangered by infestation by cycad aulacaspis scale.

  11. 谭清苏铁性别连锁的RAPD和SCAR分子标记%RAPD and SCAR Molecular Markers Linked to the Sexuality of Cycads(Cycas tanqingii D.Y.Wang)

    Institute of Scientific and Technical Information of China (English)

    景建洲; 金红; 李东亮; 陈小科; 张勇

    2007-01-01

    利用RAPD(Random amplified polymorphic DNA)分子标记技术,寻找谭清苏铁(Cycas tanqingii)中与性别相关的分子标记,筛选了160个10bp的随机引物,产生了2500多个RAPD条带.只有引物S0465(CCCCGGTAAC)产生了一条大约500bp的雌性特异RAPD标记,该分子标记出现在所有的供试雌性植株中,而所有的供试雄性植株都不具有该标记.对该特异片段进行了克隆和序列测定,并根据序列分析结果将RAPD标记转化为重复性和特异性更好的特异特征序列扩增区域(SCAR)分子标记,并命名为STQC-S465-483.分子标记的建立可用于谭清苏铁幼苗性别的早期鉴定,为谭清苏铁就地保护和迁地保护提供技术支持.

  12. Carbohydrates, pollinators, and cycads

    OpenAIRE

    2015-01-01

    Cycad biology, ecology, and horticulture decisions are not supported by adequate research, and experiments in cycad physiology in particular have been deficient. Our recent report on free sugar content in a range of cycad taxa and tissues sets the stage for developing continued carbohydrate research. Growth and development of cycad pollen, mediation of the herbivory traits of specialist pollinators, and support of expensive strobilus behavioral traits are areas of cycad pollination biology th...

  13. Does cycad aulacaspis scale (Aulacaspis yasumatsui, Hemiptera: Diaspididae) play a direct role in causing soil phytotoxicity?

    Science.gov (United States)

    Watson, Gillian; Marler, Thomas E

    2014-01-01

    Cycad aulacaspis scale (CAS, Aulacaspis yasumatsui, Hemiptera: Diaspididae) was accidentally introduced to Guam in 2003, and has caused acute mortality of the dominant, endemic forest tree Cycas micronesica. A phytotoxic legacy in the soils beneath cycad trees killed by CAS over a period of about three years has been demonstrated. The origin of the toxicity may be large quantities of CAS-encrusted cycad leaf litter. We explore the possibility that a major contribution to this toxic legacy may come from the scale insects, not just from the plant material.

  14. Crystal structures and inhibitor binding properties of plant class V chitinases: the cycad enzyme exhibits unique structural and functional features.

    Science.gov (United States)

    Umemoto, Naoyuki; Kanda, Yuka; Ohnuma, Takayuki; Osawa, Takuo; Numata, Tomoyuki; Sakuda, Shohei; Taira, Toki; Fukamizo, Tamo

    2015-04-01

    A class V (glycoside hydrolase family 18) chitinase from the cycad Cycas revoluta (CrChiA) is a plant chitinase that has been reported to possess efficient transglycosylation (TG) activity. We solved the crystal structure of CrChiA, and compared it with those of class V chitinases from Nicotiana tabacum (NtChiV) and Arabidopsis thaliana (AtChiC), which do not efficiently catalyze the TG reaction. All three chitinases had a similar (α/β)8 barrel fold with an (α + β) insertion domain. In the acceptor binding site (+1, +2 and +3) of CrChiA, the Trp168 side chain was found to stack face-to-face with the +3 sugar. However, this interaction was not found in the identical regions of NtChiV and AtChiC. In the DxDxE motif, which is essential for catalysis, the carboxyl group of the middle Asp (Asp117) was always oriented toward the catalytic acid Glu119 in CrChiA, whereas the corresponding Asp in NtChiV and AtChiC was oriented toward the first Asp. These structural features of CrChiA appear to be responsible for the efficient TG activity. When binding of the inhibitor allosamidin was evaluated using isothermal titration calorimetry, the changes in binding free energy of the three chitinases were found to be similar to each other, i.e. between -9.5 and -9.8 kcal mol(-1) . However, solvation and conformational entropy changes in CrChiA were markedly different from those in NtChiV and AtChiC, but similar to those of chitinase A from Serratia marcescens (SmChiA), which also exhibits significant TG activity. These results provide insight into the molecular mechanism underlying the TG reaction and the molecular evolution from bacterial chitinases to plant class V chitinases.

  15. Boomeranging in structural defense: phytophagous insect uses cycad trichomes to defend against entomophagy.

    Science.gov (United States)

    Marler, Thomas E

    2012-11-01

    Plant defensive behaviors that resist arthropod herbivory include trichome-mediated defenses, and variation in plant trichome morphology and abundance provides examples of the mechanistic complexities of insect-plant interactions. Trichomes were removed from Cycas revoluta cataphylls on the island of Guam to reveal Aulacaspis yasumatsui scale infestation, and predation of the newly exposed insects by pre-existing Rhyzobius lophanthae beetles commenced within one day. The quotient of predated/total scale insects was 0.5 by day 4 and stabilized at that found on adjacent glabrous leaves in about one week. The trichome phenotype covering the C. revoluta cataphyll complex offers the invasive A. yasumatsui armored scale effectual enemy-free space in this system. This pest and predator share no known evolutionary history with C. revoluta, therefore, the adaptive significance of this plant behavior in natural habitat is not yet known.

  16. Evolutionary Stasis in Cycad Plastomes and the First Case of Plastome GC-Biased Gene Conversion.

    Science.gov (United States)

    Wu, Chung-Shien; Chaw, Shu-Miaw

    2015-06-27

    In angiosperms, gene conversion has been known to reduce the mutational load of plastid genomes (the plastomes). Particularly, more frequent gene conversions in inverted repeat (IR) than in single copy (SC) regions result in contrasting substitution rates between these two regions. However, little has been known about the effect of gene conversion in the evolution of gymnosperm plastomes. Cycads (Cycadophyta) are the second largest gymnosperm group. Evolutionary study of their plastomes is limited to the basal cycad genus, Cycas. In this study, we addressed three questions. 1) Do the plastomes of other cycad genera evolve slowly as previously observed in the plastome of Cycas taitungensis? 2) Do substitution rates differ between their SC and IR regions? And 3) Does gene conversion occur in the cycad plastomes? If yes, is it AT-biased or GC-biased? Plastomes of eight species from other eight genera of cycads were sequenced. These plastomes are highly conserved in genome organization. Excluding ginkgo, cycad plastomes have significantly lower synonymous and nonsynonymous substitution rates than other gymnosperms, reflecting their evolutionary stasis in nucleotide mutations. In the IRs of cycad plastomes, the reduced substitution rates and GC-biased mutations are associated with a GC-biased gene conversion (gBGC) mechanism. Further investigations suggest that in cycads, gBGC is able to rectify plastome-wide mutations. Therefore, this study is the first to uncover the plastomic gBGC in seed plants. We also propose a gBGC model to interpret the dissimilar evolutionary patterns as well as the compositionally biased mutations in the SC and IR regions of cycad plastomes.

  17. Carbohydrates, pollinators, and cycads

    Science.gov (United States)

    Marler, Thomas E; Lindström, Anders J

    2015-01-01

    Cycad biology, ecology, and horticulture decisions are not supported by adequate research, and experiments in cycad physiology in particular have been deficient. Our recent report on free sugar content in a range of cycad taxa and tissues sets the stage for developing continued carbohydrate research. Growth and development of cycad pollen, mediation of the herbivory traits of specialist pollinators, and support of expensive strobilus behavioral traits are areas of cycad pollination biology that would benefit from a greater understanding of the role of carbohydrate relations. PMID:26479502

  18. Information-based or resource-based systems may mediate Cycas-herbivore interactions

    OpenAIRE

    Marler, Thomas E; Lindström, Anders; Terry, L. Irene

    2012-01-01

    Invasive arthropod herbivores comprise one of the greatest threats to cycad conservation both in situ and ex situ. We discuss two mechanisms, not necessarily mutually exclusive, that may underlie the disparity in Chilades pandava damage among Cycas species. In an information-based system, plant infochemicals may differentially influence oviposition behavior of Ch. pandava adults or host finding behavior of this butterfly’s natural enemies. Alternatively, heterogeneity in damage may be mediate...

  19. Comparison of intraspecific, interspecific and intergeneric chloroplast diversity in Cycads

    Science.gov (United States)

    Jiang, Guo-Feng; Hinsinger, Damien Daniel; Strijk, Joeri Sergej

    2016-01-01

    Cycads are among the most threatened plant species. Increasing the availability of genomic information by adding whole chloroplast data is a fundamental step in supporting phylogenetic studies and conservation efforts. Here, we assemble a dataset encompassing three taxonomic levels in cycads, including ten genera, three species in the genus Cycas and two individuals of C. debaoensis. Repeated sequences, SSRs and variations of the chloroplast were analyzed at the intraspecific, interspecific and intergeneric scale, and using our sequence data, we reconstruct a phylogenomic tree for cycads. The chloroplast was 162,094 bp in length, with 133 genes annotated, including 87 protein-coding, 37 tRNA and 8 rRNA genes. We found 7 repeated sequences and 39 SSRs. Seven loci showed promising levels of variations for application in DNA-barcoding. The chloroplast phylogeny confirmed the division of Cycadales in two suborders, each of them being monophyletic, revealing a contradiction with the current family circumscription and its evolution. Finally, 10 intraspecific SNPs were found. Our results showed that despite the extremely restricted distribution range of C. debaoensis, using complete chloroplast data is useful not only in intraspecific studies, but also to improve our understanding of cycad evolution and in defining conservation strategies for this emblematic group. PMID:27558458

  20. Cycad mutualist offers more than pollen transport.

    Science.gov (United States)

    Marler, Thomas E

    2010-05-01

    Specialist insects share obligate mutualisms with some contemporary cycad species whereby the insect's pollination services are rewarded with a nursery in which the insect's larvae consume the postdispersal male cone. I prevented visits of the pollinator moth Anatrachyntis sp. to male Cycas micronesica (Cycadaceae) cones to show that consumption of the cone tissue by the mutualist hastened initiation of the plant's subsequent reproductive event. This is the first documented case where removal of a postdispersal cycad pollination organ speeds up subsequent reproductive events, and the current paradigm that the offering of cone tissue as a nursery is a sacrifice by the plant in return for the pollination services is therefore inaccurate. In C. micronesica, the herbivory stage of pollination mutualism confers a cryptic benefit of cone tissue disposal, which translates into an increase in ultimate lifetime reproductive effort. The plant population relies on the pollinator for moving gametes, as well as for increasing the number of male coning events. The dual benefits afforded to the plant by associating with this pollinator shows that mutualism can operate simultaneously on very different traits.

  1. Behavioral and neurological correlates of ALS-parkinsonism dementia complex in adult mice fed washed cycad flour.

    Science.gov (United States)

    Wilson, Jason M B; Khabazian, Iraj; Wong, Margaret C; Seyedalikhani, Arash; Bains, Jaswinder S; Pasqualotto, Bryce A; Williams, David E; Andersen, Raymond J; Simpson, Rebecca J; Smith, Richard; Craig, Ulla-Kate; Kurland, Leonard T; Shaw, Christopher A

    2002-01-01

    Consumption of cycad seed products (Cycas circinalis) is one of the strongest epidemiological links to the Guamian neurological disorder amyotrophic lateral sclerosis-parkinsonism-dementia complex (ALS-PDC), however, the putative toxin which causes neurodegeneration has never been identified definitively. To reexamine this issue, 6-7-mo-old, male CD-1 mice were assessed for motor and cognitive behaviours during and following feeding with pellets made from washed cycad flour. Cycad-fed animals showed early evidence of progressive motor and cognitive dysfunctions. Neurodegeneration measured using TUNEL and caspase-3 labeling was found in neocortex, various hippocampal fields, substantia nigra, olfactory bulb, and spinal cord. In vitro studies using rat neocortex have identified toxic compounds in washed cycad flour that induce depolarizing field potentials and lead to release of lactate dehydrogenase (LDH), both blocked by AP5. High-performance liquid chromatography (HPLC)/mass spectrometry of cycad flour samples failed to show appreciable amounts of other known cycad toxins, cycasin, MAM, or BMAA; only trace amounts of BOAA were present. Isolation procedures employing these techniques identified the most toxic component as beta-sitosterol beta-D-glucoside (BSSG). The present data suggest that a neurotoxin, or a toxic metabolite, not previously identified in cycad, is able to gain access to central nervous system (CNS) resulting in neurodegeneration of specific neural populations and in motor and cognitive dysfunctions. These data are consistent with a number of major features of ALS-PDC in humans.

  2. Distribution of free and glycosylated sterols within Cycas micronesica plants

    Science.gov (United States)

    Marler, Thomas E.; Shaw, Christopher A.

    2010-01-01

    Flour derived from Cycas micronesica seeds was once the dominant source of starch for Guam's residents. Cycad consumption has been linked to high incidence of human neurodegenerative diseases. We determined the distribution of the sterols stigmasterol and β-sitosterol and their derived glucosides stigmasterol β-d-glucoside and β-sitosterol β-d-glucoside among various plant parts because they have been identified in cycad flour and have been shown to elicit neurodegenerative outcomes. All four compounds were common in seeds, sporophylls, pollen, leaves, stems, and roots. Roots contained the greatest concentration of both free sterols, and photosynthetic leaflet tissue contained the greatest concentration of both steryl glucosides. Concentration within the three stem tissue categories was low compared to other organs. Reproductive sporophyll tissue contained free sterols similar to seeds, but greater concentration of steryl glucosides than seeds. One of the glucosides was absent from pollen. Concentration in young seeds was higher than old seeds as reported earlier, but concentration did not differ among age categories of leaf, sporophyll, or vascular tissue. The profile differences among the various tissues within these organs may help clarify the physiological role of these compounds. PMID:20157629

  3. Cycad toxins, Helicobacter pylori and parkinsonism: cholesterol glucosides as the common denomenator.

    Science.gov (United States)

    Schulz, J D; Hawkes, E L; Shaw, C A

    2006-01-01

    Understanding sporadic cases of age-dependent neurodegenerative diseases such as parkinsonism requires the evaluation of potential environmental factors. Amyotrophic lateral sclerosis-parkinsonism dementia complex (ALS-PDC), a neurological disorder in which features of parkinsonism are present and for which no consistent genetic explanation has been found, has been linked to the consumption of cycad (Cycas micronesica). Similarly, epidemiological evidence suggests an association between parkinsonism and gastric ulcer caused by Helicobacter pylori infection. While common immunological and inflammatory changes have been proposed to account for the link between parkinsonism and H. pylori infection, we propose an alternate explanation based on our work on the "cycad theory" of ALS-PDC. Recent experiments in our laboratory have identified several sterol glucosides in cycad that have neurotoxic properties in vitro and that appear to be linked to the development of neurodegenerative disease in vivo. Specifically, mice fed cycad display behavioural symptoms of parkinsonism such as reduced gait length, as well as neuropathological signs such as a loss of striatal dopaminergic (DAergic) terminals and an upregulation of the dopamine D2 receptor. These cycad-derived sterol glucosides are structurally similar to cholesterol glucosides that account for a significant part pf the lipid profile of H. pylori. We hypothesize that cholesterol glucosides arising from H. pylori infection may act as neurotoxins, promoting the degeneration of the DAergic neurons affected in parkinsonism, in a similar reaction to that which is thought to link cycad consumption and ALS-PDC. This hypothesis will be tested in future studies that will include exposing mice to purified sterol or cholestorol glucosides derived from cycad and comparing these mice behaviourally and neuropathologically to ones chronically infected with H. pylori.

  4. Cycas micronesica (Cycadales) plants devoid of endophytic cyanobacteria increase in beta-methylamino-L-alanine.

    Science.gov (United States)

    Marler, Thomas E; Snyder, Laura R; Shaw, Christopher A

    2010-09-15

    Cycads are among the most ancient of extant Spermatophytes, and are known for their pharmacologically active compounds. beta-methylamino-l-alanine (BMAA) is one metabolite that been implicated as causal of human neurodegenerative diseases in Guam. We grew Cycas micronesica seedlings without endophytic cyanobacteria symbiosis, and quantified initial and ending BMAA in various plant tissues. BMAA increased 79% during nine months of seedling growth, and root tissue contained 75% of the ultimate BMAA pool. Endophytic cyanobacteria symbionts were not the source of BMAA increase in these seedlings, which contradicts previously reported claims that biosynthesis of this toxin by cyanobacteria initiates its accumulation in the Guam environment. The preferential loading of root tissue with BMAA does not support earlier reports that this toxin serves a defensive role against herbivory of leaf or seed tissues. The long history of conflicting results in Guam's cycad toxin research continues, and recent developments underscore the sense of urgency in continued research as this endangered cycad population approaches extirpation from the island.

  5. Free sugar profile in cycads.

    Science.gov (United States)

    Marler, Thomas E; Lindström, Anders J

    2014-01-01

    The sugars fructose, glucose, maltose, and sucrose were quantified in seven tissues of Zamia muricata Willd. to determine their distribution throughout various organs of a model cycad species, and in lateral structural roots of 18 cycad species to determine the variation in sugar concentration and composition among species representing every cycad genus. Taproot and lateral structural roots contained more sugars than leaf, stem, female strobilus, or coralloid roots. For example, taproot sugar concentration was 6.4-fold greater than stem sugar concentration. The dominant root sugars were glucose and fructose, and the only detected stem sugar was sucrose. Sucrose also dominated the sugar profile for leaflet and coralloid root tissue, and fructose was the dominant sugar in female strobilus tissue. Maltose was a minor constituent of taproot, leaflet, and female strobilus tissue, but absent in other tissues. The concentration of total free sugars and each of the four sugars did not differ among genera or families. Stoichiometric relationships among the sugars, such as the quotient hexoses/disaccharides, differed among organs and families. Although anecdotal reports on cycad starch have been abundant due to its historical use as human food and the voluminous medical research invested into cycad neurotoxins, this is the first report on the sugar component of the non-structural carbohydrate profile of cycads. Fructose, glucose, and sucrose are abundant in cycad tissues, with their relative abundance highly contrasting among organs. Their importance as forms of carbon storage, messengers of information, or regulators of cycad metabolism have not been determined to date.

  6. Beetle pollination of the fruit-scented cones of the South African cycad Stangeria eriopus.

    Science.gov (United States)

    Proches, Serban; Johnson, Steven D

    2009-09-01

    There has been considerable uncertainty about the importance of wind vs. insects in cycad pollination, but recent studies in several cycad genera have indicated that these are pollinated primarily, if not exclusively, by insects. Stangeria represents an isolated southern African cycad lineage previously thought to be wind-pollinated. Unlike in most other cycads, there is no evidence of cone thermogenesis in Stangeria. We found that the scent of both male and female Stangeria cones mimics that of fermented fruit, the main volatiles being esters of acetic acid, ketones, and aldehydes. We found a large variety of insect visitors on the cones, the most common ones being sap and rove beetles (Coleoptera: Nitidulidae, Staphylinidae) and fruit flies (Diptera: Drosophilidae). Of these, only sap beetles (Nitidulidae) were able to effect pollination under experimental conditions. Because sap beetles are also pollinators of Cycas and members of several ancient angiosperm families, their role in the pollination of Stangeria adds interesting details to the role this group of insects has played in the history of plant-pollinator interactions.

  7. Comparative analysis of cyanobacteria in the rhizosphere and as endosymbionts of cycads in drought-affected soils.

    Science.gov (United States)

    Cuddy, William S; Neilan, Brett A; Gehringer, Michelle M

    2012-04-01

    Does the diversity of cyanobacteria in the cycad rhizosphere relate to the cyanobiont species found in the coralloid roots of these ancient plants? The aim of this study was to identify the diversity of soil cyanobacteria occurring in the immediate vicinity of 22 colonized coralloid roots belonging to members of the cycad genera: Macrozamia, Lepidozamia, Bowenia and Cycas. The majority of coralloid roots were sampled at depths > 10 cm below the soil surface. A total of 32 cyanobacterial isolates were cultured and their 16S rRNA gene partially sequenced. Phylogenetic analysis revealed nine operational taxonomic units of soil cyanobacteria comprising 30 Nostoc spp., a Tolypothrix sp. and a Leptolyngbya sp. Microscopy indicated that all isolates were unialgal and confirmed their genus identity. Rhizospheric diversity was compared to existing data on cyanobionts isolated at the same time from the cycad coralloid root. The same isolate was present in both the cycad coralloid root and rhizosphere at only six sites. Phylogenetic evidence indicates that most rhizosphere isolates were distinct from root cyanobionts. This weak relationship between the soil cyanobacteria and cycad cyanobionts might indicate that changes in the soil community composition are due to environmental factors.

  8. 福建省的台湾苏铁%Taiwan's cycad revoluta in Fujian

    Institute of Scientific and Technical Information of China (English)

    郑芳勤; 陈家瑞

    2002-01-01

    台湾苏铁是1867年有人在淡水井边采到后送给英国人Swinhoe并被寄回英国,于1893年被Carruthers定名为台湾苏铁.近来注意到台湾产的苏铁和台湾苏铁的模式标本有较大差异.台东产的苏铁应是苏铁属中的一个新种,经沈中桴等定名为台东苏铁.现在大家都认为台湾苏铁的产地不在台湾岛,应是广东、广西等地,福建只有栽培.福建省到底有没有台湾苏铁生长?我们对其进行了必要的调查研究,结论是福建南部的漳州地区台湾苏铁不仅栽培普遍,历史悠久,而且至少是该种苏铁的原产地之一.

  9. Free Sugar Profile in Cycads

    Directory of Open Access Journals (Sweden)

    Thomas Edward Marler

    2014-10-01

    Full Text Available The sugars fructose, glucose, maltose, and sucrose were quantified in seven tissues of Zamia muricata Willd. to determine their distribution throughout various organs of a model cycad species, and in lateral structural roots of 18 cycad species to determine the variation in sugar concentration and composition among species representing every cycad genus. Taproot and lateral structural roots contained more sugars than leaf, stem, female strobilus, or coralloid roots. For example, taproot sugar concentration was 6.4-fold greater than stem sugar concentration. The dominant root sugars were glucose and fructose, and the only detected stem sugar was sucrose. Sucrose also dominated the sugar profile for leaflet and coralloid root tissue, and fructose was the dominant sugar in female strobilus tissue. Maltose was a minor constituent of taproot, leaflet, and female strobilus tissue, but absent in other tissues. The concentration of total free sugars and each of the four sugars did not differ among genera or families. Stoichiometric relationships among the sugars, such as the quotient hexoses/disaccharides, differed among organs and families. Although anecdotal reports on cycad starch have been abundant due to its historical use as human food and the voluminous medical research invested into cycad neurotoxins, this is the first report on the sugar component of the non-structural carbohydrate profile of cycads. Fructose, glucose, and sucrose are abundant in cycad tissues, with their relative abundance highly contrasting among organs. Their importance as forms of carbon storage, messengers of information, or regulators of cycad metabolism have not been determined to date.

  10. Chemical constituents of Cycas vespertilio

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    Consolacion Yasaña Ragasa

    2015-10-01

    Full Text Available ABSTRACTChemical investigation of Cycas vespertilio A. Lindstr. & K.D. Hill, Cycadaceae, a plant endemic to the Philippines, yielded pinoresinol (1, sesamin (2, paulownin (3, a mixture of β-sitosterol and stigmasterol, and triacylglycerols from the cone base; 1, 3, β-sitosterol, stigmasterol, triacylglycerols, and lariciresinol (4 from the cataphylls; β-sitosterol from the megasporophyll lamina; β-sitosterol and a mixture of trans-4-hydroxycinnamate fatty acid esters (5 and cis-4-hydroxycinnamate fatty acid esters (6 from the unripe sarcotesta; and β-sitosterol and triacylglycerols from the ripe sarcotesta. The structures 1–6 were elucidated by extensive 1D and 2D NMR spectroscopy.

  11. Variation in the chemical composition of cone volatiles within the African cycad genus Encephalartos.

    Science.gov (United States)

    Suinyuy, Terence N; Donaldson, John S; Johnson, Steven D

    2013-01-01

    Volatiles play a key role in attraction of pollinators to cycad cones, but the extent to which volatile chemistry varies among cycad species is still poorly documented. Volatile composition of male and female cones of nineteen African cycad species (Encephalartos; Zamiaceae) was analysed using headspace technique and gas chromatography-mass spectrometry (GC-MS). A total of 152 compounds were identified among the species included in this study, the most common of which were monoterpenes, nitrogen-containing compounds and unsaturated hydrocarbons. Male and female cones emitted similar volatile compounds which varied in relative amounts with two unsaturated hydrocarbons (3E)-1,3-octadiene and (3E,5Z)-1,3,5-octatriene present in the volatile profile of most species. In a multivariate analysis of volatile profiles using non-metric multidimensional scaling (NMDS), a number of species clusters were identified according to shared emission of unsaturated hydrocarbons, pyrazines, benzenoids, aldehydes, alkanes and terpenoids. In comparison, terpenoids are common in Zamia and dominant in Macrozamia species (both in the family Zamiaceae) while benzenoids, esters, and alcohols are dominant in Cycas (Cycadaceae) and in Stangeria (Stangeriaceae). It is likely that volatile variation among Encephalartos species reflects both phylogeny and adaptations to specific beetle pollinators.

  12. Microsporogenesis of Cycas and its systematic implications

    Institute of Scientific and Technical Information of China (English)

    Hua-Fen ZHANG; Hai-Bo OUYANG; Jin-Yan DU; Shou-Zhou ZHANG; Yong LI; Hong WU

    2012-01-01

    Taxonomists are divided over the infrageneric classification and species delimitation within the genus Cycas.The division is largely determined by whether a broad or narrow species concept is adopted,the latter approach being based on apparently minor morphological differences.It is well known that cytokinesis in the cells of pollen provides important evidence for plant taxonomy,particularly at the higher taxonomic level.Here we present the first broad comparison of the cytokinesis of male meiosis in five species of Cycas.A comparative analysis of microsporogenesis in Cycas was carried out using conventional microscopy,semi-thin sectioning,histochemistry,and fluorescence microscopy with a focus on the cytokinesis of meiosis in the pollen of dividing cells.Our observations confirmed that,contrary to previous reports,the cytokinesis in male meiosis of five species in Cycas is simultaneous at the end of second meiosis.The basic model of microsporogenesis and its systematic implications in Cycas is discussed based both on previous reports and our new results.

  13. A phylogeny of cycads (Cycadales) inferred from chloroplast matK gene, trnK intron, and nuclear rDNA ITS region.

    Science.gov (United States)

    Chaw, Shu-Miaw; Walters, Terrence W; Chang, Chien-Chang; Hu, Shu-Hsuan; Chen, Shin-Hsiao

    2005-10-01

    Phylogenetic relationships among the three families and 12 living genera of cycads were reconstructed by distance and parsimony criteria using three markers: the chloroplast matK gene, the chloroplast trnK intron and the nuclear ITS/5.8S rDNA sequence. All datasets indicate that Cycadaceae (including only the genus Cycas) is remotely related to other cycads, in which Dioon was resolved as the basal-most clade, followed by Bowenia and a clade containing the remaining nine genera. Encephalartos and Lepidozamia are closer to each other than to Macrozamia. The African genus Stangeria is embedded within the New World subfamily Zamiodeae. Therefore, Bowenia is an unlikely sister to Stangeria, contrary to the view that they form the Stangeriaceae. The generic status of Dyerocycas and Chigua is unsupportable as they are paraphyletic with Cycas and the Zamia, respectively. Nonsense mutations in the matK gene and indels in the other two datasets lend evidence to reinforce the above conclusions. According to the phylogenies, the past geography of the genera of cycads and the evolution of character states are hypothesized and discussed. Within the suborder Zamiieae, Stangeria, and the tribe Zamieae evolved significantly faster than other genera. The matK gene and ITS/5.8S region contain more useful information than the trnK intron in addressing phylogeny. Redelimitations of Zamiaceae, Stangeriaceae, subfamily Encephalartoideae and subtribe Macrozamiineae are necessary.

  14. Florogeographical Analysis of Spermatophytes in Cycas panzhihuaensis Assemblage%攀枝花苏铁类群的种子植物区系地理研究

    Institute of Scientific and Technical Information of China (English)

    郝云庆; 莫旭; 余志祥; 杨永琼

    2011-01-01

    苏铁是一类起源古老而孑遗的裸子植物,攀枝花苏铁国家级自然保护区内所保护的攀枝花苏铁Cycas pan-zhihuaensis,是迄今为止世界上发现的纬度最高,面积最大,数量最多的野生苏铁种群。攀枝花苏铁群落共有物种82科253属318种;珍稀濒危植物除攀枝花苏铁外,还有云南梧桐Firmiana major、栌菊木Nouelia insignis和龙棕Trachycarpus nana。区系组成以热带性质为主,尤以泛热带为多。单种科、单种属和寡种属占绝对优势,表现出区系明显的古老性和残遗性现象。干热河谷区系特征明显,金沙江干热河谷特有种和标志种占到总种数的近1/3。一些残遗种或其后裔的起源和发生背景与古地中海有密切关系。结合当地的丰富的苏铁类植物和种子蕨化石植物群的发现,可以初步推断攀枝花苏铁群落是这些古生代类型的延续,其植物区系起源古老。该地区应是中国植物区系的分化中心,也很可能就是世界苏铁植物重要的起源与发展中心。%Cycads are a class of ancient relict gymnosperm.Cycas panzhihuaensis protected in Panzhihua Cycad National Nature Reserve,is wild cycad populations with the largest area and the largest number,and is found in the world's most northern latitudes.In cycad assemblage,there are about 318 wild spermatophyte species found,belonging to 253 genera of 82 families.In addition to Cycas panzhihuaensis,the rare and endangered plants are Firmiana major,Nouelia insignis and Trachycarpus nana.Tropical elements of cycad floristic composition are the richest,and in particular pan-tropical elements are plentiful.The overwhelming of single species families,monotypic genera and minor genera clearly exhibit the ancient flora and relict phenomenon.The total number of endemic species and characteristic species of dry-hot valleys in the Jinsha River account for nearly 1/3 of total species,indicating that the attributes of dry-hot valley flora are

  15. 14种中国苏铁属优良园林植物介绍%14 Species of Excellent Cycas Landscape Plants of China

    Institute of Scientific and Technical Information of China (English)

    吴榕杰; 郭东; 刘念

    2012-01-01

    Cycads are the oldest and the most primitive exsiting seed plants on the earth, which are listed as the world l-class key protected endangered plants and the national first-grade key protected wild plants. Most of the plants in Cycas have good tolerance to sun and shade. They are easy for planting, managing and breeding, and have good potential in landscape greening. In this paper, we introduce the morphology, geographical distribution, habitat, and utilization value in landscape greening of 14 Cycas species native to China, aiming to provide references for exploitation and utilization of Chinese Cycas plant resources.%苏铁植物是我国一级重点保护野生植物,该属多数种类既耐阳又耐阴,易栽培管理和繁殖,有很好的园林应用前景。文章分别从形态特征、地理分布、生境、生存现状及园林应用价值等方面对原产中国且具有较高观赏价值的14种苏铁植物进行介绍,以此促进中国苏铁属植物资源的开发利用。

  16. [Atypical cell forms overproducing extracellular substances in population of cycad cyanobionts].

    Science.gov (United States)

    Baulina, O I; Lobakova, E S

    2003-01-01

    The ultrastructure of the cyanobionts of the greenhouse-grown cycads Cycas circinalis, Ceratozamia mexicana, and Encephalartos villosus was studied. The cyanobiont microcolonies grown in the intercellular space of the cyanobacterial zone of cortical parenchyma in the cycad coralloid roots contained two specific forms of vegetative cells with a reduced cell wall, namely, protoplasts and spheroplasts. The protoplasts and spheroplasts exhibited ultrastructural changes indicating the overproduction of two extracellular substances, one of which resembled the mucilage polysaccharides and the other was proteinous. The substances were likely to be synthesized intracellularly and then be excreted with the aid of surface vesicles or by channels in the cytoplasmic membrane to form, respectively, a slimy extracellular matrix and an additional electron-opaque envelope around the cell. At the late developmental stages, the excretion of these substances was accompanied by degradative changes in the cells, leading eventually to cell death. The physiological role of these specific cell forms and the factors that induce their development and death in the cell populations of cyanobionts are discussed.

  17. Cross Breeding Test ofCycas sexseminifera andC. panzhihuaensis%石山苏铁和攀枝花苏铁杂交育种试验(简报)

    Institute of Scientific and Technical Information of China (English)

    潘爱芳

    2014-01-01

    Artificial pollination betweenCycas sexseminifera(the male) andC. panzhihuaensis(the female) was carried out.The results showed that these two species of cycads can interspecific hybridization, but the pollination need pollinators.%以石山苏铁Cycas sexseminifera为父本,攀枝花苏铁C. panzhihuaensis为母本开展人工授粉,成功获得杂交种子并繁育成苗。结果表明,石山苏铁与攀枝花苏铁可以进行种间杂交,但传粉过程需要传粉者。

  18. 一种从苏铁叶片中有效提取RNA的方法%An Effective Protocol for the Isolation of RNA from Cycad Leaves

    Institute of Scientific and Technical Information of China (English)

    李璐; 付乾堂; 余迪求

    2008-01-01

    Conventional RNA extraction methods have been shown to produce poor-quality RNA when applied to Cycas rev-oluta because of abundant secondary metabolites included. With modification of the standard cetyltrimethylammonium bro-mide(CTAB)method by adding boras(disodium tetraborate decahydrate) andβ-mercaptoethanol to eliminate the interfer-ence of polyphenol and polysaccharides, an effective protocol was developed. This modified protocol could extract high quantities of RNA is of high quality. The RNA quality was confirmed by Northern blotting analysis and reverse tran-scription polymerase chain reaction(RT-PCR).The modified protocol could be successfully extended to other plants con-taining secondary metabolites.%由于苏铁(Cycas revoluta)叶片中含有大量的多糖多酚等次生代谢物,常规RNt提取方法很难获得优质的RNA.在常规的CTAB法中加入了硼砂和β-巯基乙醇来消除多酚和多糖的干扰,得到了一个从苏铁叶片中有效提取RNA的方法,每克鲜叶片可获得约930 ug RNA.A260/280和A260/230的纳米波长的吸收比值都约为2,表明RNA的质量较好.获得的RNA可用于Northern blot和反转录PCR等分析,也说明RNA的质量比较好.此外,改进的提取方法也适合于含有次生代谢产物的其它植物,同样可以获得优质RNA.

  19. β-Orcinol Metabolites from the Lichen Hypotrachyna revoluta

    Directory of Open Access Journals (Sweden)

    Panagiota Papadopoulou

    2007-05-01

    Full Text Available Four new β-orcinol metabolites, hypotrachynic acid (1, deoxystictic acid (2, cryptostictinolide (3 and 8 ́-methylconstictic acid (4 along with the metabolites 8 ́-methylstictic acid (5, 8 ́-methylmenegazziaic acid (6, stictic acid (7, 8 ́-ethylstictic acid (8 and atranorin (9, that have been previously described, were isolated for the first time from the tissue extracts of the lichen Hypotrachyna revoluta (Flörke Hale. The structures of the new metabolites were elucidated on the basis of extensive spectroscopic analyses. Radical scavenging activity (RSA of the metabolites isolated in adequate amounts, was evaluated using luminol chemiluminescence and comparison with Trolox®.

  20. New insights into Mesozoic cycad evolution: an exploration of anatomically preserved Cycadaceae seeds from the Jurassic Oxford Clay biota

    Science.gov (United States)

    Rees, Andrew R.; Raine, Robert J.; Rothwell, Gar W.; Hollingworth, Neville T.J.

    2017-01-01

    Most knowledge concerning Mesozoic Era floras has come from compression fossils. This has been augmented in the last 20 years by rarer permineralized material showing cellular preservation. Here, we describe a new genus of anatomically preserved gymnosperm seed from the Callovian–Oxfordian (Jurassic) Oxford Clay Formation (UK), using a combination of traditional sectioning and synchrotron radiation X-ray micro-tomography (SRXMT). Oxfordiana motturii gen. et sp. nov. is large and bilaterally symmetrical. It has prominent external ribs, and has a three-layered integument comprising: a narrow outer layer of thick walled cells; a thick middle parenchymatous layer; and innermost a thin fleshy layer. The integument has a longitudinal interior groove and micropyle, enveloping a nucellus with a small pollen chamber. The large size, bilateral symmetry and integumentary groove demonstrate an affinity for the new species within the cycads. Moreover, the internal groove in extant taxa is an autapomorphy of the genus Cycas, where it facilitates seed germination. Based upon the unique seed germination mechanism shared with living species of the Cycadaceae, we conclude that O. motturii is a member of the stem-group lineage leading to Cycas after the Jurassic divergence of the Cycadaceae from other extant cycads. SRXMT—for the first time successfully applied to fossils already prepared as slides—reveals the distribution of different mineral phases within the fossil, and allows us to evaluate the taphonomy of Oxfordiana. An early pyrite phase replicates the external surfaces of individual cells, a later carbonate component infilling void spaces. The resulting taphonomic model suggests that the relatively small size of the fossils was key to their exceptional preservation, concentrating sulfate-reducing bacteria in a locally closed microenvironment and thus facilitating soft-tissue permineralization. PMID:28875075

  1. New insights into Mesozoic cycad evolution: an exploration of anatomically preserved Cycadaceae seeds from the Jurassic Oxford Clay biota

    Directory of Open Access Journals (Sweden)

    Alan R.T. Spencer

    2017-08-01

    Full Text Available Most knowledge concerning Mesozoic Era floras has come from compression fossils. This has been augmented in the last 20 years by rarer permineralized material showing cellular preservation. Here, we describe a new genus of anatomically preserved gymnosperm seed from the Callovian–Oxfordian (Jurassic Oxford Clay Formation (UK, using a combination of traditional sectioning and synchrotron radiation X-ray micro-tomography (SRXMT. Oxfordiana motturii gen. et sp. nov. is large and bilaterally symmetrical. It has prominent external ribs, and has a three-layered integument comprising: a narrow outer layer of thick walled cells; a thick middle parenchymatous layer; and innermost a thin fleshy layer. The integument has a longitudinal interior groove and micropyle, enveloping a nucellus with a small pollen chamber. The large size, bilateral symmetry and integumentary groove demonstrate an affinity for the new species within the cycads. Moreover, the internal groove in extant taxa is an autapomorphy of the genus Cycas, where it facilitates seed germination. Based upon the unique seed germination mechanism shared with living species of the Cycadaceae, we conclude that O. motturii is a member of the stem-group lineage leading to Cycas after the Jurassic divergence of the Cycadaceae from other extant cycads. SRXMT—for the first time successfully applied to fossils already prepared as slides—reveals the distribution of different mineral phases within the fossil, and allows us to evaluate the taphonomy of Oxfordiana. An early pyrite phase replicates the external surfaces of individual cells, a later carbonate component infilling void spaces. The resulting taphonomic model suggests that the relatively small size of the fossils was key to their exceptional preservation, concentrating sulfate-reducing bacteria in a locally closed microenvironment and thus facilitating soft-tissue permineralization.

  2. Advances in the Study on Pollination Biology of Cycads%苏铁类植物传粉生物学研究进展(综述)

    Institute of Scientific and Technical Information of China (English)

    杨泉光; 宋洪涛; 杨海娟; 张洪

    2012-01-01

      苏铁类植物是现存最古老的种子植物,研究其传粉特点,对于研究种子植物的起源与演化、植物与动物的协同进化以及苏铁类植物的繁殖机制、濒危机制有重要意义。本文从苏铁雌雄株开花物候学、传粉媒介及传粉机制等方面,对苏铁类植物传粉生物学相关研究进行综述,并提出今后该类植物传粉生物学研究的建议:对更多苏铁属种类未知的传粉机制进行研究;更广泛地应用排除法研究苏铁类特别是苏铁属植物的传粉媒介,进一步探讨传粉昆虫与苏铁类的共生关系问题%  Cycads are the most primitive living seed-plants. Studying on the pollination biology of cycads has significant value for researching into the origin, phylogeny of seed plants, the evolution of dependent mutualism between the insects and cycads, as well as the mechanism of reproduction and the mechanism of endanger. In this review, we summarize the information available concerning the pollination biology of cycad, including morphology and structure of male and female cone, floral phenology of male and female plants, the medium of pollination and the mechanism of pollination. For future research, we suggested that more studies should be carried out on the pollination of cycad (especially for the Cycas) in a wider range, and the exclusion method should be conducted to determine the medium of pollination of cycad more widely, and more detailed studies should be done about the problem of that insect is in highly specialized dependent mutualisms with cycads.

  3. Maternal inheritance of plastids and mitochondria in Cycas L. (Cycadaceae).

    Science.gov (United States)

    Zhong, Zhi-Rong; Li, Nan; Qian, Dan; Jin, Jian-Hua; Chen, Tao

    2011-12-01

    Cycas is often considered a living fossil, thereby providing a unique model for revealing the evolution of spermatophytes. To date, the genetic inheritance of these archaic plants is not fully understood. The present study seeks to document the process of organelle inheritance in an interspecific cross of Cycas species. Extranuclear organelle DNA from chloroplasts and mitochondria was analyzed using both polymerase chain reaction-restriction fragment length polymorphism analysis and microscopy. Here, we show that the chloroplasts and mitochondria in the progeny of interspecific crosses between Cycas taitungensis and Cycas ferruginea were exclusively inherited from the female parent. Epifluorescence microscopic analyses of the pollen cells from Cycas elongata indicated that there was a significant degradation of organelle DNA in male reproductive cells following maturation; the DNA fluorescent signals were only seen after pollen mitosis two, but not detectable at mature stage. Lack of organelle DNA fluorescent signal in prothallial cells was confirmed by the absence of plastids and mitochondria in electronic microscopic images. In conclusion, these data suggest that the maternal plastid and mitochondrial inheritance in Cycas, native to the old world, are the same as seen in seed plants.

  4. Conserved genetic regions across angiosperms as tools to develop single-copy nuclear markers in gymnosperms: an example using cycads.

    Science.gov (United States)

    Salas-Leiva, Dayana E; Meerow, Alan W; Francisco-Ortega, Javier; Calonje, Michael; Griffith, M Patrick; Stevenson, Dennis W; Nakamura, Kyoko

    2014-07-01

    Several individuals of the Caribbean Zamia clade and other cycad genera were used to identify single-copy nuclear genes for phylogeographic and phylogenetic studies in Cycadales. Two strategies were employed to select target loci: (i) a tblastX search of Arabidopsis conserved ortholog sequence (COS) set and (ii) a tblastX search of Arabidopsis-Populus-Vitis-Oryza Shared Single-Copy genes (APVO SSC) against the EST Zamia databases in GenBank. From the first strategy, 30 loci were selected, and from the second, 16 loci. In both cases, the matching GenBank accessions of Zamia were used as a query for retrieving highly similar sequences from Cycas, Picea, Pinus species or Ginkgo biloba. After retrieving and aligning all the sequences in each locus, intron predictions were completed to assist in primer design. PCR was carried out in three rounds to detect paralogous loci. A total of 29 loci were successfully amplified as a single band of which 20 were likely single-copy loci. These loci showed different diversity and divergence levels. A preliminary screening allowed us to select 8 promising loci (40S, ATG2, BG, GroES, GTP, LiSH, PEX4 and TR) for the Zamia pumila complex and 4 loci (COS26, GroES, GTP and HTS) for all other cycad genera.

  5. Extensive functional pleiotropy of REVOLUTA substantiated through forward genetics.

    Science.gov (United States)

    Porth, Ilga; Klápste, Jaroslav; McKown, Athena D; La Mantia, Jonathan; Hamelin, Richard C; Skyba, Oleksandr; Unda, Faride; Friedmann, Michael C; Cronk, Quentin C B; Ehlting, Jürgen; Guy, Robert D; Mansfield, Shawn D; El-Kassaby, Yousry A; Douglas, Carl J

    2014-02-01

    In plants, genes may sustain extensive pleiotropic functional properties by individually affecting multiple, distinct traits. We discuss results from three genome-wide association studies of approximately 400 natural poplar (Populus trichocarpa) accessions phenotyped for 60 ecological/biomass, wood quality, and rust fungus resistance traits. Single-nucleotide polymorphisms (SNPs) in the poplar ortholog of the class III homeodomain-leucine zipper transcription factor gene REVOLUTA (PtREV) were significantly associated with three specific traits. Based on SNP associations with fungal resistance, leaf drop, and cellulose content, the PtREV gene contains three potential regulatory sites within noncoding regions at the gene's 3' end, where alternative splicing and messenger RNA processing actively occur. The polymorphisms in this region associated with leaf abscission and cellulose content are suggested to represent more recent variants, whereas the SNP associated with leaf rust resistance may be more ancient, consistent with REV's primary role in auxin signaling and its functional evolution in supporting fundamental processes of vascular plant development.

  6. Cycads: Fossil evidence of late paleozoic origin

    Science.gov (United States)

    Mamay, S.H.

    1969-01-01

    Plant fossils from Lower Permian strata of the southwestern United States have been interpreted as cycadalean megasporophylls. They are evidently descended from spermopterid elements of the Pennsylvanian Taeniopteris complex; thus the known fossil history of the cycads is extended from the Late Triassic into the late Paleozoic. Possible implications of the Permian fossils toward evolution of the angiosperm carpel are considered.

  7. Arundina graminifolia var. revoluta (Arethuseae, Orchidaceae) has fern-type rheophyte characteristics in the leaves.

    Science.gov (United States)

    Yorifuji, Eri; Ishikawa, Naoko; Okada, Hiroshi; Tsukaya, Hirokazu

    2015-03-01

    Morphological and molecular variation between Arundina graminifolia var. graminifolia and the dwarf variety, A. graminifolia var. revoluta, was examined to assess the validity of their taxonomic characteristics and genetic background for identification. Morphological analysis in combination with field observations indicated that A. graminifolia var. revoluta is a rheophyte form of A. graminifolia characterized by narrow leaves, whereas the other morphological characteristics described for A. graminifolia var. revoluta, such as smaller flowers and short stems, were not always accompanied by the narrower leaf phenotype. Molecular analysis based on matK sequences indicated that only partial differentiation has occurred between A. graminifolia var. graminifolia and A. graminifolia var. revoluta. Therefore, we should consider the rheophyte form an ecotype rather than a variety. Anatomical observations of the leaves revealed that the rheophyte form of A. graminifolia possessed characteristics of the rheophytes of both ferns and angiosperms, such as narrower palisade tissue cells and thinner spongy tissue cells, as well as fewer cells in the leaf-width direction and fewer mesophyll cell layers.

  8. Phylogeny of the cycads based on multiple single-copy nuclear genes: congruence of concatenated parsimony, likelihood and species tree inference methods.

    Science.gov (United States)

    Salas-Leiva, Dayana E; Meerow, Alan W; Calonje, Michael; Griffith, M Patrick; Francisco-Ortega, Javier; Nakamura, Kyoko; Stevenson, Dennis W; Lewis, Carl E; Namoff, Sandra

    2013-11-01

    Despite a recent new classification, a stable phylogeny for the cycads has been elusive, particularly regarding resolution of Bowenia, Stangeria and Dioon. In this study, five single-copy nuclear genes (SCNGs) are applied to the phylogeny of the order Cycadales. The specific aim is to evaluate several gene tree-species tree reconciliation approaches for developing an accurate phylogeny of the order, to contrast them with concatenated parsimony analysis and to resolve the erstwhile problematic phylogenetic position of these three genera. DNA sequences of five SCNGs were obtained for 20 cycad species representing all ten genera of Cycadales. These were analysed with parsimony, maximum likelihood (ML) and three Bayesian methods of gene tree-species tree reconciliation, using Cycas as the outgroup. A calibrated date estimation was developed with Bayesian methods, and biogeographic analysis was also conducted. Concatenated parsimony, ML and three species tree inference methods resolve exactly the same tree topology with high support at most nodes. Dioon and Bowenia are the first and second branches of Cycadales after Cycas, respectively, followed by an encephalartoid clade (Macrozamia-Lepidozamia-Encephalartos), which is sister to a zamioid clade, of which Ceratozamia is the first branch, and in which Stangeria is sister to Microcycas and Zamia. A single, well-supported phylogenetic hypothesis of the generic relationships of the Cycadales is presented. However, massive extinction events inferred from the fossil record that eliminated broader ancestral distributions within Zamiaceae compromise accurate optimization of ancestral biogeographical areas for that hypothesis. While major lineages of Cycadales are ancient, crown ages of all modern genera are no older than 12 million years, supporting a recent hypothesis of mostly Miocene radiations. This phylogeny can contribute to an accurate infrafamilial classification of Zamiaceae.

  9. 394 Les fruits de Cycas (Cycadacea) des Comores : utilisation ...

    African Journals Online (AJOL)

    ibrahim

    Cycas des Comores n'ont jamais fait l'objet d'étude scientifique approfondie. ..... Après 25 min environ, la fin de la cuisson donne de petits pains appelés ..... projet PER (Pôle d'Excellence Régionale) pour leur soutien financier dans cette ...

  10. Previous studies underestimate BMAA concentrations in cycad flour.

    Science.gov (United States)

    Cheng, Ran; Banack, Sandra Anne

    2009-01-01

    The traditional diet of the Chamorro people of Guam has high concentrations of the neurotoxin BMAA, beta-methyl-amino-L-alanine, in cycad tortillas and from animals that feed on cycad seeds. We measured BMAA concentration in washed cycad flour and compared different extraction methods used by previous researchers in order to determine how much BMAA may have been unaccounted for in prior research. Samples were analyzed with AQC precolumn derivatization using HPLC-FD detection and verified with UPLC-UV, UPLC-MS, and triple quadrupole LC/MS/MS. Although previous workers had studied only the free amino acid component of BMAA in washed cycad flour, we detected significant levels of protein-associated BMAA in washed cycad flour. These data support a link between ALS/PDC and exposure to BMAA.

  11. The cycad neurotoxic amino acid, beta-N-methylamino-L-alanine (BMAA), elevates intracellular calcium levels in dissociated rat brain cells.

    Science.gov (United States)

    Brownson, Delia M; Mabry, Tom J; Leslie, Steven W

    2002-10-01

    Seeds of the Guam cycad Cycas micronesica K.D. Hill (Cycadaceae), which contain ss-methylamino-L-alanine (BMAA), have been implicated in the etiology of the devastating neurodisease ALS-PDC that is found among the native Chamorros on Guam. The disease also occurs in the native populations on Irian Jaya and the Kii Peninsula of Japan, and in all three areas the cycad seeds are used either dietarily or medically. ALS-PDC is a complex of amyotrophic lateral sclerosis and parkinsonism dementia complex with additional symptoms of Alzheimer's. It is well known that Ca(2+) elevations in brain cells can lead to cell death and neurodiseases. Therefore, we evaluated the ability of the cycad toxin BMAA to elevate the intracellular calcium concentration ([Ca(2+)](i)) in dissociated newborn rat brain cells loaded with fura-2 dye. BMAA produced an increase in intracellular calcium levels in a concentration-dependent manner. The increases were dependent not only on extracellular calcium concentrations, but also significantly on the presence of bicarbonate ion. Increasing concentrations of sodium bicarbonate resulted in a potentiation of the BMAA-induced [Ca(2+)](i) elevation. The bicarbonate dependence did not result from the increased sodium concentration or alkalinization of the buffer. Our results support the hypothesis that the neurotoxicity of BMAA is due to an excitotoxic mechanism, involving elevated intracellular calcium levels and bicarbonate. Furthermore, since BMAA alone produced no increase in Ca(2+) levels, these results suggest the involvement of a product of BMAA and CO(2), namely a beta-carbamate, which has a structure similar to other excitatory amino acids (EAA) such as glutamate; thus, the causative agent for ALS-PDC on Guam and elsewhere may be the beta-carbamate of BMAA. These findings support the theory that some forms of other neurodiseases may also involve environmental toxins.

  12. A molecular systematic study of the African endemic cycads

    OpenAIRE

    2012-01-01

    M.Sc. Africa's cycads (66 species and 2 subspecies in two endemic genera: Encephalartos and Stangeria) are extremely endangered with four species extinct in the wild and 80% threatened (CR, EN, or VU) with all included in CITES Appendix 1. Although South Africa has some of the world’s strictest cycad legislation, these plants are still under threat from illegal collection for horticulture and medicine especially where they are seized in an unidentifiable condition. Currently developed legi...

  13. Cataphylls of the Middle Triassic cycad Antarcticycas schopfii and new insights into cycad evolution.

    Science.gov (United States)

    Hermsen, Elizabeth J; Taylor, Thomas N; Taylor, Edith L; Stevenson, Dennis Wm

    2006-05-01

    Cataphylls associated with the Middle Triassic stem genus Antarcticycas are described, and their impact on understanding cycad evolution is discussed. The cataphylls of Antarcticycas are triangular in outline and flattened adaxially with lateral flanges. The outer surfaces are covered with a ramentum of filamentous hairs, the epidermis is a single cell layer thick, and the ground tissue is parenchymatous with mucilage canals and sclereids. Vascular bundles form a distinct inverted omega-shaped pattern characteristic of the Cycadales observed in petioles of extant species. The structures in Antarcticycas are interpreted as cataphylls based on overall morphology, presence of straight vascular strands in the cortex of the associated stem, and lack of fascicular cambia in the vascular bundles. Because much of the overall diversity of Cycadales is represented by fossils, integrating fossil taxa into explicit phylogenetic hypotheses is important for understanding cycad evolution. Therefore, character and minimum age mapping were performed on a phylogeny of extant and fossil taxa including Antarcticycas. The results suggest that major extant lineages of Cycadales had diverged by the Permian to Triassic and that certain synapomorphies for Cycadales had evolved by the Permian. Evidence of insect feeding on Antarcticycas suggests that associations between cycads and insects are ancient.

  14. Cycads: their evolution, toxins, herbivores and insect pollinators

    Science.gov (United States)

    Schneider, Dietrich; Wink, Michael; Sporer, Frank; Lounibos, Philip

    2002-06-01

    Palaeobiological evidence indicates that gymnosperms were wind-pollinated and that insect pollination began in angiosperms in the Lower Cretaceous (ca. 135 mya) leading to close associations between higher plants and their pollinators. Cycads, which were widespread and pervasive throughout the Mesozoic (250-65 mya) are among the most primitive living seed-plants found today. Because pollination by beetles and by thrips has now been detected in several modern cycads, it is attractive to speculate that some insects and cycads had already developed similar mutualistic interactions in the Triassic (250-205 mya), long before the advent of angiosperms. We also draw attention to another key factor in this insect-plant relationship, namely secondary, defensive plant substances which must always have controlled interspecific interactions. Cycads mainly produce toxic azoglucosides and neurotoxic non-protein amino acids (e.g. BMAA), which apparently are crucial elements in the development and maintenance of mutualism (pollination) and parasitism (herbivory) by cycad-linked herbivores. We now add new results on the uptake and storage of the main toxin, cycasin, of the Mexican cycad Zamia furfuracea by its pollinator, the weevil Rhopalotria mollis, and by a specialist herbivore of Zamia integrifolia, the aposematic Atala butterfly Eumaeus atala.

  15. Cycas sancti-lasallei (Cycadaceae), a new species from the Philippines

    NARCIS (Netherlands)

    Agoo, E.M.G.; Madulid, D.A.

    2012-01-01

    Cycas sancti-lasallei, a new species from Mindanao Island, the Philippines is described and illustrated. It can be distinguished from other Cycas species in the Philippines in having long leaves, undulating leaflets, and megasporophyll lamina with a semi-orbicular to orbicular base and triangular to

  16. Phytochemical Screening and In vitro Evaluation of Free Radical Scavenging Activity of Dionysia revoluta L.

    Directory of Open Access Journals (Sweden)

    Mohammad Ali Farboodniay Jahromi

    2015-03-01

    Full Text Available Dionysia revoluta L., a plant of Primulaceae family is used for treating ulcers and relieving pain in Iranian traditional system of medicine. The present study was aimed at preliminary phytochemical investigation and evaluation of antioxidant characteristics of D. revolute L. ethanol extract and its various fractions. Total phenolic content was determined by Folin–Ciocalteu method. Evaluation of total flavonoid was carried out by the use of an aluminium chloride/sodium carbonate colorimetric procedure. Lipid peroxidation inhibitory effect of ethanol extract was studied and compared with that of butylated hydroxytoluene (BHT. Radical scavenging properties of ethanolic extract and various fractions were determined by 2,2-diphenyl-l-picrylhydrazyl (DPPH and nitric oxide methods. High phenolic and flavonoid contents and significant radical scavenging properties were detected for the ethyl, acetate and n-butanol fractions. Comparisons were made with known reference antioxidant compounds ascorbic acid, quercetin, and gallic acid. The radical scavenging effect of n-butanol fraction was the highest among all fractions. Acid hydrolysis of n-butanol fraction led to a significant enhancement in its phenolic and flavonoid contents and DPPH scavenging efficacy. The total phenolic content showed a good correlation with radical scavenging activity. The antioxidant activity found in the ethyl acetate and n-butanol fractions of D. revoluta L. may be attributed to the presence of flavonoids and other phenolic compounds. Among various chemical constituents of this plant, the concentration of flavonoids seems to prevail remarkably as indicated by thin layer chromatography of various fractions and diagnostic colour reactions. The results suggest that D. revoluta bears a remarkable radical scavenging and antioxidant activity and is worthy of further detailed phytochemical and antioxidant studies.

  17. REVOLUTA and WRKY53 connect early and late leaf development in Arabidopsis

    DEFF Research Database (Denmark)

    Xie, Yakun; Huhn, Kerstin; Brandt, Ronny;

    2014-01-01

    that class III homeodomain leucine zipper (HD-ZIPIII) transcription factors, which are known to be involved in basic pattern formation, have an additional role in controlling the onset of leaf senescence in Arabidopsis. Several potential direct downstream genes of the HD-ZIPIII protein REVOLUTA (REV) have...... of WRKY53 in response to oxidative stress, and mutations in HD-ZIPIII genes strongly delay the onset of senescence. Thus, a crosstalk between early and late stages of leaf development appears to contribute to reproductive success....

  18. Morphological and genetic diversity of symbiotic cyanobacteria from cycads.

    Science.gov (United States)

    Thajuddin, Nooruddin; Muralitharan, Gangatharan; Sundaramoorthy, Mariappan; Ramamoorthy, Rengasamy; Ramachandran, Srinivasan; Akbarsha, Mohamed Abdulkadar; Gunasekaran, Muthukumaran

    2010-06-01

    The morphological and genetic diversity of cyanobacteria associated with cycads was examined using PCR amplification techniques and 16S rRNA gene sequence analysis. Eighteen symbiotic cyanobacteria were isolated from different cycad species. One of the symbiotic isolates was a species of Calothrix, a genus not previously reported to form symbioses with Cycadaceae family, and the remainder were Nostoc spp. Axenic cyanobacterial strains were compared by DNA amplification using PCR with either short arbitrary primers or primers specific for the repetitive sequences. Based on fingerprint patterns and phenograms, it was revealed that cyanobacterial symbionts exhibit important genetic diversity among host plants, both within and between cycad populations. A phylogenetic analysis based on 16S rRNA gene sequence analysis revealed that most of the symbiotic cyanobacterial isolates fell into well-separated clades.

  19. Cycads and their association with certain neurodegenerative diseases.

    Science.gov (United States)

    Rivadeneyra-Domínguez, E; Rodríguez-Landa, J F

    2014-01-01

    Cycads are ornamental plants that in some parts of the world are used as fresh food or raw material for producing flour with a high nutritional value. However, they also contain active compounds, including methylazoxymethanol, β-methylamino-L-alanine, β-alanine-L-oxalylamino and cycasin, which may produce neurotoxic effects. Some studies have associated consuming cycads and their derivatives with neurodegenerative diseases such as amyotrophic lateral sclerosis/Parkinsonism dementia complex, and other diseases characterised by motor impairment. Therefore, we must not forget that any product, no matter how natural, may present health risks or benefits depending on the chemical compounds it contains and the susceptibility of those who consume it. We completed a literature analysis to evaluate the neurotoxic properties of cycads and their association with neurological diseases in order to provide structured scientific information that may contribute to preventing health problems in people who use these plants. Cycads contain neurotoxic compounds that may contribute to the development of neurological diseases when ingested improperly. We must be mindful of the fact that while some plants have a high nutritional value and may fill the food gap for vulnerable populations, they can also be toxic and have a negative impact on health. Copyright © 2013 Sociedad Española de Neurología. Published by Elsevier Espana. All rights reserved.

  20. Biomagnification of cycad neurotoxins in flying foxes: implications for ALS-PDC in Guam.

    Science.gov (United States)

    Banack, Sandra Anne; Cox, Paul Alan

    2003-08-12

    Beta-methylamino-L-alanine (BMAA) occurs in higher levels in museum specimens of the Guamanian flying fox than in the cycad seeds the flying foxes feed on, confirming the hypothesis that cycad neurotoxins are biomagnified within the Guam ecosystem. Consumption of a single flying fox may have resulted in an equivalent BMAA dose obtained from eating 174 to 1,014 kg of processed cycad flour. Traditional feasting on flying foxes may be related to the prevalence of neuropathologic disease in Guam.

  1. The historical demography and genetic variation of the endangered Cycas multipinnata (Cycadaceae in the red river region, examined by chloroplast DNA sequences and microsatellite markers.

    Directory of Open Access Journals (Sweden)

    Yi-Qing Gong

    Full Text Available Cycas multipinnata C.J. Chen & S.Y. Yang is a cycad endemic to the Red River drainage region that occurs under evergreen forest on steep limestone slopes in Southwest China and northern Vietnam. It is listed as endangered due to habitat loss and over-collecting for the ornamental plant trade, and only several populations remain. In this study, we assess the genetic variation, population structure, and phylogeography of C. multipinnata populations to help develop strategies for the conservation of the species. 60 individuals from six populations were used for chloroplast DNA (cpDNA sequencing and 100 individuals from five populations were genotyped using 17 nuclear microsatellites. High genetic differentiation among populations was detected, suggesting that pollen or seed dispersal was restricted within populations. Two main genetic clusters were observed in both the cpDNA and microsatellite loci, corresponding to Yunnan China and northern Vietnam. These clusters indicated low levels of gene flow between the regions since their divergence in the late Pleistocene, which was inferred from both Bayesian and coalescent analysis. In addition, the result of a Bayesian skyline plot based on cpDNA portrayed a long history of constant population size followed by a decline in the last 50,000 years of C. multipinnata that was perhaps affected by the Quaternary glaciations, a finding that was also supported by the Garza-Williamson index calculated from the microsatellite data. The genetic consequences produced by climatic oscillations and anthropogenic disturbances are considered key pressures on C. multipinnata. To establish a conservation management plan, each population of C. multipinnata should be recognized as a Management Unit (MU. In situ and ex situ actions, such as controlling overexploitation and creating a germplasm bank with high genetic diversity, should be urgently implemented to preserve this species.

  2. The Historical Demography and Genetic Variation of the Endangered Cycas multipinnata (Cycadaceae) in the Red River Region, Examined by Chloroplast DNA Sequences and Microsatellite Markers

    Science.gov (United States)

    Gong, Yi-Qing; Zhan, Qing-Qing; Nguyen, Khang Sinh; Nguyen, Hiep Tien; Wang, Yue-Hua; Gong, Xun

    2015-01-01

    Cycas multipinnata C.J. Chen & S.Y. Yang is a cycad endemic to the Red River drainage region that occurs under evergreen forest on steep limestone slopes in Southwest China and northern Vietnam. It is listed as endangered due to habitat loss and over-collecting for the ornamental plant trade, and only several populations remain. In this study, we assess the genetic variation, population structure, and phylogeography of C. multipinnata populations to help develop strategies for the conservation of the species. 60 individuals from six populations were used for chloroplast DNA (cpDNA) sequencing and 100 individuals from five populations were genotyped using 17 nuclear microsatellites. High genetic differentiation among populations was detected, suggesting that pollen or seed dispersal was restricted within populations. Two main genetic clusters were observed in both the cpDNA and microsatellite loci, corresponding to Yunnan China and northern Vietnam. These clusters indicated low levels of gene flow between the regions since their divergence in the late Pleistocene, which was inferred from both Bayesian and coalescent analysis. In addition, the result of a Bayesian skyline plot based on cpDNA portrayed a long history of constant population size followed by a decline in the last 50,000 years of C. multipinnata that was perhaps affected by the Quaternary glaciations, a finding that was also supported by the Garza-Williamson index calculated from the microsatellite data. The genetic consequences produced by climatic oscillations and anthropogenic disturbances are considered key pressures on C. multipinnata. To establish a conservation management plan, each population of C. multipinnata should be recognized as a Management Unit (MU). In situ and ex situ actions, such as controlling overexploitation and creating a germplasm bank with high genetic diversity, should be urgently implemented to preserve this species. PMID:25689828

  3. [Microbial complexes from apogeotropic roots and from rhizosphere of cycad plants].

    Science.gov (United States)

    Lobakova, E S; Orazova, M Kh; Dobrovol'skaia, T G

    2003-01-01

    The microbial complexes of soil, the rhizosphere, and the rhizoplane of the apogeotropic (coralloid) roots of cycad plants were comparatively studied. The aseptically prepared homogenates of the surface-sterilized coralloid roots did not contain bacterial microsymbiont, indicating that it was absent in the root tissues. At the same time, associated bacteria belonging to different taxonomic groups were detected in increasing amounts in the cycad rhizoplane, rhizosphere, and the surrounding soil. The bacterial communities found in the cycad rhizoplane and the surrounding soil were dominated by bacteria from the genus Bacillus. The saprotrophic bacteria and fungi colonizing the cycad rhizosphere and rhizoplane were dominated by microorganisms capable of degrading the plant cell walls. The local degradation of the cell wall was actually observed on the micrographs of the thin sections of cycad roots in the form of channels, through which symbiotic cyanobacterial filaments can penetrate into the cortical parenchyma.

  4. Extensive Functional Pleiotropy of REVOLUTA Substantiated through Forward Genetics1[W][OPEN

    Science.gov (United States)

    Porth, Ilga; Klápště, Jaroslav; McKown, Athena D.; La Mantia, Jonathan; Hamelin, Richard C.; Skyba, Oleksandr; Unda, Faride; Friedmann, Michael C.; Cronk, Quentin C.B.; Ehlting, Jürgen; Guy, Robert D.; Mansfield, Shawn D.; El-Kassaby, Yousry A.; Douglas, Carl J.

    2014-01-01

    In plants, genes may sustain extensive pleiotropic functional properties by individually affecting multiple, distinct traits. We discuss results from three genome-wide association studies of approximately 400 natural poplar (Populus trichocarpa) accessions phenotyped for 60 ecological/biomass, wood quality, and rust fungus resistance traits. Single-nucleotide polymorphisms (SNPs) in the poplar ortholog of the class III homeodomain-leucine zipper transcription factor gene REVOLUTA (PtREV) were significantly associated with three specific traits. Based on SNP associations with fungal resistance, leaf drop, and cellulose content, the PtREV gene contains three potential regulatory sites within noncoding regions at the gene’s 3′ end, where alternative splicing and messenger RNA processing actively occur. The polymorphisms in this region associated with leaf abscission and cellulose content are suggested to represent more recent variants, whereas the SNP associated with leaf rust resistance may be more ancient, consistent with REV’s primary role in auxin signaling and its functional evolution in supporting fundamental processes of vascular plant development. PMID:24309192

  5. [Heterocysts with reduced cell walls in populations of cycad cyanobionts].

    Science.gov (United States)

    Baulina, O I; Lobakova, E S

    2003-01-01

    The ultrastructure of the cyanobionts of the greenhouse-grown cycads Cycads circinalis, Ceratozamia mexicana, and Encephalartos villosus was studied. In addition to heterocysts with the typical ultrastructure, the cyanobiont microcolonies also contained altered heterocysts with reduced cell walls, which might dominate in all regions of the coralloid roots. The altered heterocysts represented a protoplast enclosed in a heterocyst-specific envelope with additional layers. Some heterocysts contained an additional reticular protoplast-enclosing sheath below the heterocyst-specific envelope, whereas the other heterocysts contained an additional electron-opaque outer layer. The substance of the inner sheath of the former heterocysts resembled the polysaccharides of mucilage, which fills the intercellular space of plant tissues, whereas the electron-opaque outer layer of the latter heterocysts probably had a protein nature. The substances that constitute the sheath and the outer layer are likely to be synthesized intracellularly and then released with the aid of membrane-bounded vesicles or by channels in the cytoplasmic membrane.

  6. Chloroplast phylogenomics indicates that Ginkgo biloba is sister to cycads.

    Science.gov (United States)

    Wu, Chung-Shien; Chaw, Shu-Miaw; Huang, Ya-Yi

    2013-01-01

    Molecular phylogenetic studies have not yet reached a consensus on the placement of Ginkgoales, which is represented by the only living species, Ginkgo biloba (common name: ginkgo). At least six discrepant placements of ginkgo have been proposed. This study aimed to use the chloroplast phylogenomic approach to examine possible factors that lead to such disagreeing placements. We found the sequence types used in the analyses as the most critical factor in the conflicting placements of ginkgo. In addition, the placement of ginkgo varied in the trees inferred from nucleotide (NU) sequences, which notably depended on breadth of taxon sampling, tree-building methods, codon positions, positions of Gnetopsida (common name: gnetophytes), and including or excluding gnetophytes in data sets. In contrast, the trees inferred from amino acid (AA) sequences congruently supported the monophyly of a ginkgo and Cycadales (common name: cycads) clade, regardless of which factors were examined. Our site-stripping analysis further revealed that the high substitution saturation of NU sequences mainly derived from the third codon positions and contributed to the variable placements of ginkgo. In summary, the factors we surveyed did not affect results inferred from analyses of AA sequences. Congruent topologies in our AA trees give more confidence in supporting the ginkgo-cycad sister-group hypothesis.

  7. Extending the generality of leaf economic design principles in the cycads, an ancient lineage.

    Science.gov (United States)

    Zhang, Yong-Jiang; Cao, Kun-Fang; Sack, Lawren; Li, Nan; Wei, Xue-Mei; Goldstein, Guillermo

    2015-04-01

    Cycads are the most ancient lineage of living seed plants, but the design of their leaves has received little study. We tested whether cycad leaves are governed by the same fundamental design principles previously established for ferns, conifers and angiosperms, and characterized the uniqueness of this relict lineage in foliar trait relationships. Leaf structure, photosynthesis, hydraulics and nutrient composition were studied in 33 cycad species from nine genera and three families growing in two botanical gardens. Cycads varied greatly in leaf structure and physiology. Similarly to other lineages, light-saturated photosynthetic rate per mass (Am ) was related negatively to leaf mass per area and positively to foliar concentrations of chlorophyll, nitrogen (N), phosphorus and iron, but unlike angiosperms, leaf photosynthetic rate was not associated with leaf hydraulic conductance. Cycads had lower photosynthetic N use efficiency and higher photosynthetic performance relative to hydraulic capacity compared with other lineages. These findings extend the relationships shown for foliar traits in angiosperms to the cycads. This functional convergence supports the modern synthetic understanding of leaf design, with common constraints operating across lineages, even as they highlight exceptional aspects of the biology of this key relict lineage.

  8. Developmental regulation of CYCA2s contributes to tissue-specific proliferation in Arabidopsis.

    Science.gov (United States)

    Vanneste, Steffen; Coppens, Frederik; Lee, Eunkyoung; Donner, Tyler J; Xie, Zidian; Van Isterdael, Gert; Dhondt, Stijn; De Winter, Freya; De Rybel, Bert; Vuylsteke, Marnik; De Veylder, Lieven; Friml, Jiří; Inzé, Dirk; Grotewold, Erich; Scarpella, Enrico; Sack, Fred; Beemster, Gerrit T S; Beeckman, Tom

    2011-07-19

    In multicellular organisms, morphogenesis relies on a strict coordination in time and space of cell proliferation and differentiation. In contrast to animals, plant development displays continuous organ formation and adaptive growth responses during their lifespan relying on a tight coordination of cell proliferation. How developmental signals interact with the plant cell-cycle machinery is largely unknown. Here, we characterize plant A2-type cyclins, a small gene family of mitotic cyclins, and show how they contribute to the fine-tuning of local proliferation during plant development. Moreover, the timely repression of CYCA2;3 expression in newly formed guard cells is shown to require the stomatal transcription factors FOUR LIPS/MYB124 and MYB88, providing a direct link between developmental programming and cell-cycle exit in plants. Thus, transcriptional downregulation of CYCA2s represents a critical mechanism to coordinate proliferation during plant development.

  9. 苏铁类植物4个属的导管与被子植物导管结构特征的比较研究%Comparative Studies on Structural Feature of Vessels of Four Genera of Cycads with Angiosperm

    Institute of Scientific and Technical Information of China (English)

    黄玉源; 廖文波; 张宏达; 王佳卓; 伍映辉

    2008-01-01

    The tissues of leaf of Cycas taiwaniana,Bowenia serrulata and Dioon edule and tissue of root of Macrozamia longispina of cycads, and leaves of Michelia alba and Amygdalus persica of angiosperm were observed by scanning electron microscope. The results showed that there are many types of vessels in four genera of two families of cycads,the manner and process of development and constitution in structural characteristics of vessel of cycads and angiosperm are identical,some characters of vessel such as inclined extent of perforation plate of end wall etc. showed that some angiosperm are more primitive then that of cycads. In vessels of species of angiosperm, many are band shape, and without end wall, only have two lateral walls and another two narrow margins, the top is acute or with an arc margin, many perforations located in lateral wall. Cognized to vessel of cycads, help us to understand the mechanism which these most primitive seed plants extant how to adapted to harsh environments and their evolutionary level, and has significance to use efficiency measure protect these rarity plants and has significance to plant anatomy, plant systematics and plant evolution.%对苏铁属的台湾苏铁(Cycas taiwaniana)、波温铁属的细齿波温铁(Bowenia serrulata)、双子铁属的双子铁(Dioon edule)叶的羽片,大泽米铁属长刺大泽米铁(Macrozamia longispina)的根,以及被子植物的白兰(Michelia alba)和桃(Amygdalus persica)的叶组织进行了电子扫描显微镜的观察研究,结果表明,2个科4个属苏铁植物的导管类型是丰富的,导管的结构组成方式、发育过程与被子植物是一致的;例如导管端壁倾斜度等结构特征显示,一些被子植物导管的结构比苏铁类植物的要原始.在被子植物的导管中有许多为端部呈扁平的带状,而且还带有扭曲状,没有端壁,只有两面的侧壁及另两侧的很窄的边,在带状的侧壁上具有许多的穿孔.这在过去未见有报道.对苏

  10. Unstable, self-limiting thermochemical temperature oscillations in Macrozamia cycads.

    Science.gov (United States)

    Roemer, Robert B; Terry, L Irene; Walter, Gimme H

    2008-06-01

    Field measurements and laboratory experiments on the Australian cycads Macrozamia lucida and Macrozamia macleayi demonstrate that their cones' diel peak thermogenic temperature increase varies systematically with cone stage, with single thermogenic temperature peaks occurring daily for up to 2 weeks and reaching 12 degrees C above ambient at midstage. The initiation, magnitude and timing of those peaks are strongly modulated by ambient temperature; the period between successive thermogenic temperature peaks is not circadian, and light is neither necessary nor sufficient to initiate a thermogenic event. A mathematical analysis is developed that provides a unified explanation of the experimental results. It describes these unstable, self-limiting thermogenic events in terms of conservation of energy and a first-order chemical reaction rate model that includes an Arrhenius equation dependence of the cone's metabolic heating rate on the cone temperature.

  11. Ontogenetic shifts in plant-plant interactions in a rare cycad within angiosperm communities.

    Science.gov (United States)

    Álvarez-Yépiz, Juan C; Búrquez, Alberto; Dovčiak, Martin

    2014-06-01

    Gymnosperms and angiosperms can co-occur within the same habitats but key plant traits are thought to give angiosperms an evolutionary competitive advantage in many ecological settings. We studied ontogenetic changes in competitive and facilitative interactions between a rare gymnosperm (Dioon sonorense, our target species) and different plant and abiotic neighbours (conspecific-cycads, heterospecific-angiosperms, or abiotic-rocks) from 2007 to 2010 in an arid environment of northwestern Mexico. We monitored survival and growth of seedlings, juveniles, and adults of the cycad Dioon sonorense to evaluate how cycad survival and relative height growth rate (RHGR) responded to intra- and interspecific competition, canopy openness, and nearest neighbour. We tested spatial associations among D. sonorense life stages and angiosperm species and measured ontogenetic shifts in cycad shade tolerance. Canopy openness decreased cycad survival while intraspecific competition decreased survival and RHGR during early ontogeny. Seedling survival was higher in association with rocks and heterospecific neighbours where intraspecific competition was lower. Shade tolerance decreased with cycad ontogeny reflecting the spatial association of advanced stages with more open canopies. Interspecific facilitation during early ontogeny of our target species may promote its persistence in spite of increasing interspecific competition in later stages. We provide empirical support to the long-standing assumption that marginal rocky habitats serve as refugia from angiosperm competition for slow-growing gymnosperms such as cycads. The lack of knowledge of plant-plant interactions in rare or endangered species may hinder developing efficient conservation strategies (e.g. managing for sustained canopy cover), especially under the ongoing land use and climatic changes.

  12. Seed dispersal of the Australian cycad Macrozamia miquelii (Zamiaceae): are cycads megafauna-dispersed "grove forming" plants?

    Science.gov (United States)

    Hall, John A; Walter, Gimme H

    2013-06-01

    Plants that invest in large, heavy seeds and colorful, fleshy fruits or analogous structures seem adapted for dispersal by large vertebrates. Some such plants, like Australian cycads in the genus Macrozamia, do not disperse well, which could be explained by seed-dispersal relationships with megafauna that are rare or extinct in contemporary ecosystems. Such plants provide an opportunity to investigate the ecological consequences of low seed-dispersal distances. • We investigated seed dispersal of Macrozamia miquelii in Central Queensland by tracking the fate of marked seeds, identifying the dispersal fauna and quantifying population demography and spatial structure. • We found that 70-100% of marked seeds remained within 1 m of maternal females (cycads are dioecious). Of the 812 seeds recovered (from 840 originally marked) only 24 dispersed >1 m from maternal females, the greatest observed dispersal being 5 m. We found an average of 2.2 seedlings and 0.7 juveniles within 1.5 m of mature females, which suggests that most seeds that remain in the vicinity of maternal females perish. Within-stand densities ranged between 1000 and 5000 plants/ha. The brushtail possum Trichosurus vulpecula was the only animal observed to move the seeds. • Macrozamia are adapted for dispersal by megafauna that are rare or absent in contemporary ecosystems. We argue that Macrozamia are "grove forming" plants that derive ecological benefit from existing as high-density, spatially discrete populations, the function of megafaunal dispersal adaptations being the infrequent dispersal of seeds en masse to establish new such groves in the landscape.

  13. [State strategy for Cycad (Zamiaceae) conservation: a proposal for the State of Hidalgo, Mexico].

    Science.gov (United States)

    Vite, Aurelia; Pulido, María T; Flores-Vázquez, Juan C

    2013-09-01

    Mexico has the second largest cycad diversity in the world, and the Sierra Madre Oriental (SMO) is one of the richest biogeographic regions for these plants. Despite there is a general Cycad National Program in the country, there are no state-level cycad conservation strategies or programs. Thus the aim of this study was to propose a cycad conservation strategy for the state of Hidalgo, which is located in the Southern part of the SMO. For this, a cycad species inventory was made in the state, for which three methods were used: review of published literature; consultation in the main Mexican herbaria to verify botanical specimens; and exhaustive field research to compare findings with previously reported species and to recognize new records at the county and state level. The proposed research work strategy combined the following elements: prioritize the county and local areas with greatest cycad species richness; prioritize the species least resistant to environmental change and/or having restricted geographic distribution; and to consider the main uses of these plants by local residents. The results showed that Hidalgo has three genera and eight species ofcycads: Ceratozamia fuscoviridis, C. latifolia, C. mexicana, C. sabatoi, Dioon edule, Zamia fischeri, Z. loddigesii and Z. vazquezii, all of which are considered by the International Union for Conservation of Nature (IUCN). This study added two new species records for Hidalgo and 21 at the county level. The species are distributed in 26 counties, of which Chapulhuacán and Pisaflores are notable for their high species richness. Hidalgo has the fourth-greatest cycad species richness among Mexican states, although its area accounts for only 1.07% of the country. The state's diversity is greater than in other states with larger area, and even than in some other entire countries in Mesoamerica. The presented state cycad conservation strategy proposes that a total of some 11,325 ha to be conserved in nine zones

  14. Animal models of brain maldevelopment induced by cycad plant genotoxins.

    Science.gov (United States)

    Kisby, Glen E; Moore, Holly; Spencer, Peter S

    2013-12-01

    Cycads are long-lived tropical and subtropical plants that contain azoxyglycosides (e.g., cycasin, macrozamin) and neurotoxic amino acids (notably β-N-methylamino-l-alanine l-BMAA), toxins that have been implicated in the etiology of a disappearing neurodegenerative disease, amyotrophic lateral sclerosis and parkinsonism-dementia complex that has been present in high incidence among three genetically distinct populations in the western Pacific. The neuropathology of amyotrophic lateral sclerosis/parkinsonism-dementia complex includes features suggestive of brain maldevelopment, an experimentally proven property of cycasin attributable to the genotoxic action of its aglycone methylazoxymethanol (MAM). This property of MAM has been exploited by neurobiologists as a tool to study perturbations of brain development. Depending on the neurodevelopmental stage, MAM can induce features in laboratory animals that model certain characteristics of epilepsy, schizophrenia, or ataxia. Studies in DNA repair-deficient mice show that MAM perturbs brain development through a DNA damage-mediated mechanism. The brain DNA lesions produced by systemic MAM appear to modulate the expression of genes that regulate neurodevelopment and contribute to neurodegeneration. Epigenetic changes (histone lysine methylation) have also been detected in the underdeveloped brain after MAM administration. The DNA damage and epigenetic changes produced by MAM and, perhaps by chemically related substances (e.g., nitrosamines, nitrosoureas, hydrazines), might be an important mechanism by which early-life exposure to genotoxicants can induce long-term brain dysfunction.

  15. Serine proteinase inhibitors in seeds of Cycas siamensis and other gymnosperms.

    Science.gov (United States)

    Konarev, Alexander V; Lovegrove, Alison; Shewry, Peter R

    2008-10-01

    Seeds of 32 species selected from two of the four major groups of gymnosperms, the ancient Cycadales and the economically important Coniferales, were analysed for inhibitors (I) of the serine proteinases trypsin (T), chymotrypsin (C), subtilisin (S) and elastase (E) using isoelectric focusing (IEF) combined with gelatin replicas. Subtilisin inhibitors were detected in 17 species, being particularly active in the Cycadales. Several species of the genera Cephalotaxus, Pseudotsuga and Cycas contained inhibitors active against elastase while strong CSTIs and CSIs were also present in Cycas pectinata and C. siamensis. No inhibitors were detected in seeds of Chamaecyparis, Thuja, Abies, Larix, Picea and Pinus spp. Serine proteinase inhibitors were purified from seeds of C. siamensis by affinity chromatography using trypsin and chymotrypsin, IEF and SDS-PAGE. Several CSTI components with M(r) ranging from 4000 to 18,000 were partially sequenced using Edman degradation and mass spectrometry. Most of the sequences were similar to a hypothetical protein encoded by an mRNA from sporophylls of C. rumphii which in turn was similar to Kunitz-type proteinase inhibitors from flowering plants. Analysis of expressed sequence tag (EST) databases confirmed the presence of mRNAs encoding Kunitz-type inhibitors in the Cycadales and Coniferales and also demonstrated their presence in a third major group of gymnosperms, the Ginkgoales. This is the first report of Kunitz-type serine proteinase inhibitors from plants other than Angiosperms.

  16. RNA Editing Sites Exist in Protein-coding Genes in the Chloroplast Genome of Cycas taitungensis

    Institute of Scientific and Technical Information of China (English)

    Haiyan Chen; Likun Deng; Yuan Jiang; Ping Lu; Jianing Yu

    2011-01-01

    RNA editing is a post-transcriptional process that results in modifications of ribonucleotides at specific locations.In land plants editing can occur in both mitochondria and chloroplasts and most commonly involves C-to-U changes,especially in seed plants.Using prediction and experimental determination,we investigated RNA editing in 40 protein-coding genes from the chloroplast genome of Cycas taitungensis.A total of 85 editing sites were identified in 25 transcripts.Comparison analysis of the published editotypes of these 25 transcripts in eight species showed that RNA editing events gradually disappear during plant evolution.The editing in the first and third codon position disappeared quicker than that in the second codon position,ndh genes have the highest editing frequency while serine and proline codons were more frequently edited than the codons of other amino acids.These results imply that retained RNA editing sites have imbalanced distribution in genes and most of them may function by changing protein structure or interaction.Mitochondrion protein-coding genes have three times the editing sites compared with chloroplast genes of Cycas,most likely due to slower evolution speed.

  17. Species delimitation of the Cycas segmentifida complex (Cycadaceae resolved by phylogenetic and distance analyses of molecular data

    Directory of Open Access Journals (Sweden)

    Xiuyan eFeng

    2016-02-01

    Full Text Available The Cycas segmentifida complex consists of eight species whose distributions overlap in a narrow region in Southwest China. These eight taxa are also morphologically similar and are difficult to be distinguished. Consequently, their taxonomic status has been a matter of discussion in recent years. To study this species complex, we sequenced four plastid intergenic spacers (cpDNA, three nuclear genes and genotyped 12 microsatellites for the eight taxa from 19 different localities. DNA sequences were analyzed using Maximum Likelihood (ML method and Bayesian Inference (BI, and microsatellites were analyzed using the Neighbor-joining (NJ and structure inference methods. Results of cpDNA, nuclear gene GTP and microsatellites all rejected the hypotheses that this complex consisted of eight taxa or one distinct lineages (species but two previously described species were adopted: Cycas guizhouensis K. M. Lan et R. F. Zou and Cycas segmentifida D. Y. Wang et C. Y. Deng. Cycas longlinensis H. T. Chang et Y. C. Zhong was included in C. guizhouensis and the other five taxa were included in C. segmentifida. Our species delimitation inferred from molecular data largely corresponds to morphological differentiation. However, the other two nuclear genes were unable to resolve species boundaries for this complex independently. This study offered evidences from different genomes for dealing with the species boundaries and taxonomical treatment of the C. segmentifida complex in an integrated perspective.

  18. Phyto-Chemical Evaluation and Anti-oxidant potentiality of Cycas beddomei Dyer Male cone aqueous Extract

    Directory of Open Access Journals (Sweden)

    Mahendra Nath Mitta

    2014-06-01

    Full Text Available Cycas beddomei Dyer, an endemic and critically endangered, tropical, dry deciduous, dioecious gymnosperm present in varied region of adjunct areas of Tirumala Hillocks, Seshachalam Biosphere Reserve, Eastern ghats, India. The objective of the study was to investigate antioxidant capacity of aqueous extracts of microsporophylls of male cones of Cycas beddomei. This study deals with the quantitative estimation of phytoconstituents viz., Total Phenolic Content (TPC, Total Flavonoid Content (TFC, Total Flavonols (TF, Total Proanthocyanidins (TPA, Extraction Yield (EY , Quantitative analysis soluble carbohydrates, Starch, Crude fibre, Proteins, Moisture, Ash and Mineral composition of aqueous extract of male cone of cycas beddomei has been carried out. Moreover, the assessment of antioxidant capacity by standard established calorimetric methods viz., DPPH assay, TAC and ABTS assay. Entire data has evaluated statistically. Results depicted High contents of TPC, TFC, TF and TPA and exerted anti-radical aptitude. Significant correlation has been found between quantities of phyto-constituents and anti-oxidant assays. With the results, it is confirmed that the logistics of aqueous cone extract of Cycas beddomei as potential anti-oxidant by evaluating the bioavailability of phytoconstituents and provided scientific base as a valuable natural antioxidant and therapeutic agent.

  19. Can a botanic garden cycad collection capture the genetic diversity in a wild population?

    Science.gov (United States)

    Conservation of plant species often requires ex situ (off-site) cultivation of living collections. Cycads constitute the most imperiled major group of plants, and ex situ collections are an important part of conservation planning for this group, given seed recalcitrance, difficulties with tissue cul...

  20. Cycad biodiversity in the Bahama Archipelago and conservation genetics of the Critically Endangered Zamia lucayana (Zamiaceae)

    Science.gov (United States)

    A conservation assessment for the three species of cycads native to the Bahamas Islands is presented. Results are based on extensive field surveys in all the islands where these species are found [Zamia angustifolia (native in Eleuthera), Z. integrifolia (native in Abaco, Andros, Eleuthera, Grand Ba...

  1. Host selection of symbiotic cyanobacteria in 31 species of the Australian cycad genus: Macrozamia (Zamiaceae).

    Science.gov (United States)

    Gehringer, Michelle M; Pengelly, Jasper J L; Cuddy, William S; Fieker, Claus; Forster, Paul I; Neilan, Brett A

    2010-06-01

    The nitrogen-fixing cyanobacterium Nostoc is a commonly occurring terrestrial and aquatic cyanobacterium often found in symbiosis with a wide range of plant, algal, and fungal species. We investigated the diversity of cyanobacterial species occurring within the coralloid roots of different Macrozamia cycad species at diverse locations throughout Australia. In all, 74 coralloid root samples were processed and 56 endosymbiotic cyanobacteria were cultured. DNA was isolated from unialgal cultures and a segment of the 16S rRNA gene was amplified and sequenced. Microscopic analysis was performed on representative isolates. Twenty-two cyanobacterial species were identified, comprising mostly Nostoc spp. and a Calothrix sp. No correlation was observed between a cycad species and its resident cyanobiont species. The predominant cyanobacterium isolated from 18 root samples occurred over a diverse range of environmental conditions and within 14 different Macrozamia spp. Phylogenetic analysis indicated that endosymbionts were not restricted to previously described terrestrial species. An isolate clustering with Nostoc PCC7120, an aquatic strain, was identified. This is the first comprehensive study to identify the endosymbionts within a cycad genus using samples obtained from their natural habitats. These results indicate that there is negligible host specialization of cyanobacterial endosymbionts within the cycad genus Macrozamia in the wild.

  2. New discovery of fossil cycad-like plants from the Middle Jurassic of West Liaoning, China

    Institute of Scientific and Technical Information of China (English)

    WANG Yongdong; ZHANG Wu; ZHENG Shaolin; SAIKI Keni'chi; LI Nan

    2005-01-01

    @@ The Cycadales are one of the most ancient lineages ofseed plants, with a fossil record that extends over 250 mil-lion years. Cycads are believed to have originated fromthe Late Palaeozoic, and reached its maximum diversityand distribution during the Mesozoic; however, their evo-lutionary history has remained relatively poorly under-stood[1―4].

  3. A New Genus of Fossil Cycads Yixianophyllum gen. nov. from the Late Jurassic Yixian Formation, Western Liaoning, China

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    A new genus of fossil Cycads, Yixianophyllum gen. nov., is reported here. The specimens were collected from the southern hill of Jinjiagou village, Toudaohezi Town, Yixian County, western Liaoning Province, China. The fossil plant-bearing bed belongs to the lower part, the Zhuanchengzi bed, of the Upper Jurassic Yixian Formation (Yixianian). The new genus in leaf shape, venation and epidermal structure shows a transitional form between Mesozoic Cycads (Ctenis, Nilssonia) and modern Cycads (Stangeria and Encephalartos). Since the features of these specimens differ from any known genera of Cycads, a new genetic name Yixianophyllum is proposed for these leaves. Typical species, Yixianophyllum jinjiagouense gen. et sp. nov. is described here. A supposed evolutionary tendency of Cycadean leaf-forms with Taeniopteris-type is discussed.

  4. Testing co-evolutionary hypotheses over geological timescales: interactions between Mesozoic non-avian dinosaurs and cycads.

    Science.gov (United States)

    Butler, Richard J; Barrett, Paul M; Kenrick, Paul; Penn, Malcolm G

    2009-02-01

    The significance of co-evolution over ecological timescales is well established, yet it remains unclear to what extent co-evolutionary processes contribute to driving large-scale evolutionary and ecological changes over geological timescales. Some of the most intriguing and pervasive long-term co-evolutionary hypotheses relate to proposed interactions between herbivorous non-avian dinosaurs and Mesozoic plants, including cycads. Dinosaurs have been proposed as key dispersers of cycad seeds during the Mesozoic, and temporal variation in cycad diversity and abundance has been linked to dinosaur faunal changes. Here we assess the evidence for proposed hypotheses of trophic and evolutionary interactions between these two groups using diversity analyses, a new database of Cretaceous dinosaur and plant co-occurrence data, and a geographical information system (GIS) as a visualisation tool. Phylogenetic evidence suggests that the origins of several key biological properties of cycads (e.g. toxins, bright-coloured seeds) likely predated the origin of dinosaurs. Direct evidence of dinosaur-cycad interactions is lacking, but evidence from extant ecosystems suggests that dinosaurs may plausibly have acted as seed dispersers for cycads, although it is likely that other vertebrate groups (e.g. birds, early mammals) also played a role. Although the Late Triassic radiations of dinosaurs and cycads appear to have been approximately contemporaneous, few significant changes in dinosaur faunas coincide with the late Early Cretaceous cycad decline. No significant spatiotemporal associations between particular dinosaur groups and cycads can be identified - GIS visualisation reveals disparities between the spatiotemporal distributions of some dinosaur groups (e.g. sauropodomorphs) and cycads that are inconsistent with co-evolutionary hypotheses. The available data provide no unequivocal support for any of the proposed co-evolutionary interactions between cycads and herbivorous dinosaurs

  5. N sub 2 -fixation by freshly isolated Nostoc from coralloid roots of the cycad Macrozamia riedlei (Fisch. ex Gaud. ) Gardn

    Energy Technology Data Exchange (ETDEWEB)

    Lindblad, P.; Atkins, C.A.; Pate, J.S. (Univ. of Uppsala (Sweden) Univ. of Western Australia, Nedlands (Australia))

    1991-03-01

    Nitrogenase (EC 1.7.99.2) activity (acetylene reduction) and nitrogen fixation ({sup 15}N{sub 2} fixation) were measured in cyanobacteria freshly isolated from the coralloid roots of Macrozamia riedlei (Fisch. ex Gaud.) Gardn. The data indicate that cyanobacteria within cycad coralloid roots are differentiated specifically for symbiotic functioning in a microaerobic environment. Specializations include a high heterocyst frequency, enhanced permeability to O{sub 2}, and a direct dependence on the cycad for substrates to support nitrogenase activity.

  6. Evolutionary dynamics of a cycad obligate pollination mutualism - Pattern and process in extant Macrozamia cycads and their specialist thrips pollinators.

    Science.gov (United States)

    Brookes, D R; Hereward, J P; Terry, L I; Walter, G H

    2015-12-01

    Obligate pollination mutualisms are rare and few have been investigated deeply. This paper focuses on one such mutualism involving thrips in the genus Cycadothrips that pollinate cycads in the genus Macrozamia. Both represent old lineages relative to insects and plants generally, are endemic to Australia, and are mutually co-dependent. The phylogenetic analyses presented here demonstrate that the pollinator is much more diverse than previously considered, with each pollinator lineage being extremely specific to between one and three host species where these latter share part of their distribution. The new species diversity we demonstrate in Cycadothrips all presently falls under the species name C. chadwicki, and these different lineages diversified during two periods. An older divergence, beginning 7.3Mya (4.4-11.1, 95% HPD), resulted in three major lineages, and then further diversification within each of these three lineages took place at most 1.1Mya (0.6-1.8, 95% HPD). These divergence estimates correspond to times when aridification was increasing in Australia, suggesting that population fragmentation following climatic change has played a significant role in the evolutionary history of Cycadothrips and Macrozamia. This means that co-diversification of the host and pollinator in allopatry appears to be the dominant process affecting species diversity. Host switching is also clearly evident in the discrepancy between the divergence times of the C. chadwicki lineage and C. albrechti, about 10.8Mya (6.0-17.1, 95% HPD), and their hosts, at about 1.1Mya (0.2-3.4Mya, 95% HPD), in that the pollinator split pre-dates the origin of the associated host species of each. These results add to the body of evidence that the evolutionary processes important in obligate pollinator mutualisms are more varied than previously assumed.

  7. Biological characteristics of wild Cycas fairylakea population in Guangdong Province,China

    Institute of Scientific and Technical Information of China (English)

    JIAN Shuguang; LIU Nian; GAO Zezheng; WEI Qiang; XIE Zhenhua; WU Mei; REN Hai

    2006-01-01

    There are five wild populations of Cycas fairylakea in Guangdong Province,China,three of which are newly found.A study of the biological characteristics of C.fairylakea populations showed that this species had a narrow colonization area within 300 hm2,and an island pattern of distribution.Because of the overexploitation,urbanization,environment pollution,plant diseases,and insect pests,the wild populations and individuals of C.fairylakea decreased markedly in the past decades.All five populations have an opposite pyramid age structure,few coning plants,few seed production,and low level of seed germination rate or sterility.In conclusion,C.fairylakea in Guangdong Province was threatened seriously and an urgent need to take effective efforts to protect the plants and habitats in its location sites was required.

  8. Review of the lady beetle genus Phaenochilus Weise (Coleoptera: Coccinellidae: Chilocorini), with description of a new species from Thailand and that preys on cycad auacaspis scale, Aulacaspis yasumatsui Takagi (Diaspididae)

    Science.gov (United States)

    Species of the genus Phaenochilus are reviewed, keyed, and illustrated, and an annotated checklist provided. A new species, Phaenochilus kashaya, that feeds on an invasive pest of cycads, cycad aulacaspis scale, Aulacaspis yasumatsui Takagi (Hemiptera: Sternorrhyncha: Diaspididae), is described fro...

  9. The value of research to selling the conservation of threatened species: the case of Cycas micronesica (Cycadopsida: Cycadales: Cycadaceae

    Directory of Open Access Journals (Sweden)

    Thomas E. Marler

    2014-11-01

    Full Text Available A case study is described wherein strong focus on research during the developing threats that caused the elevation of Cycas micronesica from Near Threatened to Endangered status illustrates how targeted research results may be used to aid in conservation education. We argue that the devotion of a portion of conservation funds to research in addition to mitigation efforts may improve ultimate conservation success.

  10. The mitochondrial genome of the gymnosperm Cycas taitungensis contains a novel family of short interspersed elements, Bpu sequences, and abundant RNA editing sites.

    Science.gov (United States)

    Chaw, Shu-Miaw; Shih, Arthur Chun-Chieh; Wang, Daryi; Wu, Yu-Wei; Liu, Shu-Mei; Chou, The-Yuan

    2008-03-01

    The mtDNA of Cycas taitungensis is a circular molecule of 414,903 bp, making it 2- to 6-fold larger than the known mtDNAs of charophytes and bryophytes, but similar to the average of 7 elucidated angiosperm mtDNAs. It is characterized by abundant RNA editing sites (1,084), more than twice the number found in the angiosperm mtDNAs. The A + T content of Cycas mtDNA is 53.1%, the lowest among known land plants. About 5% of the Cycas mtDNA is composed of a novel family of mobile elements, which we designated as "Bpu sequences." They share a consensus sequence of 36 bp with 2 terminal direct repeats (AAGG) and a recognition site for the Bpu 10I restriction endonuclease (CCTGAAGC). Comparison of the Cycas mtDNA with other plant mtDNAs revealed many new insights into the biology and evolution of land plant mtDNAs. For example, the noncoding sequences in mtDNAs have drastically expanded as land plants have evolved, with abrupt increases appearing in the bryophytes, and then in the seed plants. As a result, the genomic organizations of seed plant mtDNAs are much less compact than in other plants. Also, the Cycas mtDNA appears to have been exempted from the frequent gene loss observed in angiosperm mtDNAs. Similar to the angiosperms, the 3 Cycas genes nad1, nad2, and nad5 are disrupted by 5 group II intron squences, which have brought the genes into trans-splicing arrangements. The evolutionary origin and invasion/duplication mechanism of the Bpu sequences in Cycas mtDNA are hypothesized and discussed.

  11. Cycad neurotoxins, consumption of flying foxes, and ALS-PDC disease in Guam.

    Science.gov (United States)

    Cox, Paul Alan; Sacks, Oliver W

    2002-03-26

    The Chamorro people of Guam have been afflicted with a complex of neurodegenerative diseases (now known as ALS-PDC) with similarities to ALS, AD, and PD at a far higher rate than other populations throughout the world. Chamorro consumption of flying foxes may have generated sufficiently high cumulative doses of plant neurotoxins to result in ALS-PDC neuropathologies, since the flying foxes forage on neurotoxic cycad seeds.

  12. Two genera of Aulacoscelinae beetles reflexively bleed azoxyglycosides found in their host cycads.

    Science.gov (United States)

    Prado, Alberto; Ledezma, Julieta; Cubilla-Rios, Luis; Bede, Jacqueline C; Windsor, Donald M

    2011-07-01

    Aulacoscelinae beetles have an ancient relationship with cycads (Cycadophyta: Zamiaceae), which contain highly toxic azoxyglycoside (AZG) compounds. How these "primitive" leaf beetles deal with such host-derived compounds remains largely unknown. Collections were made of adult Aulacoscelis appendiculata from Zamia cf. elegantissima in Panama, A. vogti from Dioon edule in Mexico, and Janbechynea paradoxa from Zamia boliviana in Bolivia. Total AZG levels were quantified in both cycad leaves and adult beetles by high performance liquid chromatography (HPLC). On average, cycad leaves contained between 0.5-0.8% AZG (frozen weight, FW), while adult beetles feeding on the same leaves contained even higher levels of the compounds (average 0.9-1.5% FW). High AZG levels were isolated from reflex bleeding secreted at the leg joints when beetles were disturbed. Nuclear magnetic resonance and mass spectroscopy identified two AZGs, cycasin and macrozamin, in the reflex bleeding; this is the first account of potentially plant-derived compounds in secretions of the Aulacoscelinae. These data as well as the basal phylogenetic position of the Aulacoscelinae suggest that sequestration of plant secondary metabolites appeared early in leaf beetle evolution.

  13. Geographical matching of volatile signals and pollinator olfactory responses in a cycad brood-site mutualism.

    Science.gov (United States)

    Suinyuy, Terence N; Donaldson, John S; Johnson, Steven D

    2015-10-07

    Brood-site mutualisms represent extreme levels of reciprocal specialization between plants and insect pollinators, raising questions about whether these mutualisms are mediated by volatile signals and whether these signals and insect responses to them covary geographically in a manner expected from coevolution. Cycads are an ancient plant lineage in which almost all extant species are pollinated through brood-site mutualisms with insects. We investigated whether volatile emissions and insect olfactory responses are matched across the distribution range of the African cycad Encephalartos villosus. This cycad species is pollinated by the same beetle species across its distribution, but cone volatile emissions are dominated by alkenes in northern populations, and by monoterpenes and a pyrazine compound in southern populations. In reciprocal choice experiments, insects chose the scent of cones from the local region over that of cones from the other region. Antennae of beetles from northern populations responded mainly to alkenes, while those of beetles from southern populations responded mainly to pyrazine. In bioassay experiments, beetles were most strongly attracted to alkenes in northern populations and to the pyrazine compound in southern populations. Geographical matching of cone volatiles and pollinator olfactory preference is consistent with coevolution in this specialized mutualism.

  14. Taxonomic aspects and coning ecology of Cycas circinalis L. (Cycadales: Cycadaceae, a threatened species of India

    Directory of Open Access Journals (Sweden)

    A.J.S. Raju

    2011-01-01

    Full Text Available Cycas circinalis is Red Listed Endangered species. It is a tropical dry deciduous dioecious shrub confined to the Western Ghats and its adjacent regions. It reproduces asexually and sexually. Asexual mode exists in male plants only but further studies are suggested for confirmation. In the asexual mode, bulbils arise as offshoots of the stem; they germinate either on the same plant to produce additional shoots or fall off to germinate and produce new plants. Sexual reproduction involves cone and seed production. The sex of the plant is identifiable only during the coning phase. The plant is typically anemophilous and it is highly effective for optimal seed set. The cones of both sexes show weak thermogenesis and odour production during maturation process and these two processes have absolutely no role in pollination. Coning and leaf flushing events occur in quick succession in both sexes. Seed set is optimal and the seed coat is four-layered consisting of sarcotesta, sclerotesta, a thick layer of spongy tissue and a thin membranous jacket enclosing the female gametophyte tissue; the spongy layer is important to cause floatation in water for seed dispersal which occurs during the rainy season.

  15. A Cycad Name Which Should be Misidentified-South China Cycad%一个被错误鉴定的苏铁名称--华南苏铁

    Institute of Scientific and Technical Information of China (English)

    王定跃

    2000-01-01

    Cycas rumphii长期被误认为是中国华南地区常见分布或广泛培栽的苏铁种类,中名称之"华南苏铁".作者研究表明,C.rumphii在我国大陆并不分布,而且栽培稀少,而所谓的"华南苏铁"属错误鉴定,实际是指台湾苏铁(C.taiwaniana)、仙湖苏铁(C.fairylakea)与四川苏铁(C.szechuanensis)等一类苏铁."华南苏铁"一名应予以废弃,而恢复C.rumphii的中文名刺叶苏铁.

  16. Exposing the illegal trade in cycad species (Cycadophyta: Encephalartos) at two traditional medicine markets in South Africa using DNA barcoding.

    Science.gov (United States)

    Williamson, J; Maurin, O; Shiba, S N S; van der Bank, H; Pfab, M; Pilusa, M; Kabongo, R M; van der Bank, M

    2016-09-01

    Species in the cycad genus Encephalartos are listed in CITES Appendix I and as Threatened or Protected Species in terms of South Africa's National Environmental Management: Biodiversity Act (NEM:BA) of 2004. Despite regulations, illegal plant harvesting for medicinal trade has continued in South Africa and resulted in declines in cycad populations and even complete loss of sub-populations. Encephalartos is traded at traditional medicine markets in South Africa in the form of bark strips and stem sections; thus, determining the species traded presents a major challenge due to a lack of characteristic plant parts. Here, a case study is presented on the use of DNA barcoding to identify cycads sold at the Faraday and Warwick traditional medicine markets in Johannesburg and Durban, respectively. Market samples were sequenced for the core DNA barcodes (rbcLa and matK) as well as two additional regions: nrITS and trnH-psbA. The barcoding database for cycads at the University of Johannesburg was utilized to assign query samples to known species. Three approaches were followed: tree-based, similarity-based, and character-based (BRONX) methods. Market samples identified were Encephalartos ferox (Near Threatened), Encephalartos lebomboensis (Endangered), Encephalartos natalensis (Near Threatened), Encephalartos senticosus (Vulnerable), and Encephalartos villosus (Least Concern). Results from this study are crucial for making appropriate assessments and decisions on how to manage these markets.

  17. Conserved genetic regions across angiosperms as tools to develop single-copy nuclear markers in gymnosperms: an example using cycads

    Science.gov (United States)

    Several individuals of the Caribbean Zamia clade (Zamia pumila complex) and other cycads were used to identify potential low copy nuclear genes for further studies of the phylogeographic relationships within the Caribbean Z. pumila complex and also among genera of Cycadales. Two strategies were used...

  18. Cutting propagation technology of cycad plants%苏铁植物扦插繁殖育苗技术

    Institute of Scientific and Technical Information of China (English)

    伍群玉; 马书云; 杜万平

    2013-01-01

    从幼苗繁殖、移栽、管理等过程介绍了苏铁植物扦插繁殖育苗技术。%From seedling propagation, transplantation, management etc to introduce Cutting Propagation Technology of Cycad Plants.

  19. Phylogeny of the cycads based on multiple single copy nuclear genes: congruence of concatenation and species tree inference methods

    Science.gov (United States)

    Despite a recent new classification, a stable tree of life for the cycads has been elusive, particularly regarding resolution of Bowenia, Stangeria and Dioon. In this study we apply five single copy nuclear genes (SCNGs) to the phylogeny of the order Cycadales. We specifically aim to evaluate seve...

  20. Molecular systematics and evolution in an African cycad-weevil interaction: Amorphocerini (Coleoptera: Curculionidae: Molytinae) weevils on Encephalartos.

    Science.gov (United States)

    Downie, D A; Donaldson, J S; Oberprieler, R G

    2008-04-01

    Weevils in the tribe Amorphocerini have been implicated in pollination of Encephalartos species in southern Africa. The services they render these plants and the unique attributes of the cycad-weevil interaction make them important from both conservation and evolutionary standpoints. Oberprieler [Oberprieler, R.G., 1996. Systematics and evolution of the tribe Amorphocerini, with a review of the cycad weevils of the world. Ph.D. dissertation, University of the Free State, Bloemfontein, South Africa], using morphological characters, proposed a tentative hypothesis of relationships among the Amorphocerini which is tested here using DNA sequence data. Sequences from one mitochondrial and three nuclear genes were used to infer phylogenetic relationships, levels of sequence divergence, evolution of host associations, and patterns of speciation in this tribe. The results are reasonably consistent with the morphological hypothesis of relationships and species concepts, though important differences are observed, particularly in relationships among a Porthetes hispidus Boheman species group, which is indicated to have experienced recent divergences. In general, low levels of sequence divergence among species within two of the three genera indicate a recent radiation of this tribe onto African cycads, thus while cycad-insect interactions have often been considered ancient this may not be the case for some extant interactions. A complex pattern of host shifts onto both closely related and more distantly related hosts is suggested.

  1. Caterpillars of Eumaeus childrenae (Lepidoptera: Lycaenidae) feeding on two species of cycads (Zamiaceae) in the Huasteca region, Mexico.

    Science.gov (United States)

    Contreras-Medina, Raúl; Ruiz-Jiménez, Carlos A; Luna Vega, Isolda

    2003-03-01

    There are few genera of butterflies that feed on cycads. Among them the genus Eumaeus (Lycaenidae) presents aposematic coloration in all its life stages. In this work we report for the first time the herbivory of young leaflets of Ceratozamia mexicana and Zamia fischeri (Zamiaceae) by caterpillars of E. childrenae in their natural habitat in the Huasteca region, Mexico.

  2. CycADS: an annotation database system to ease the development and update of BioCyc databases.

    Science.gov (United States)

    Vellozo, Augusto F; Véron, Amélie S; Baa-Puyoulet, Patrice; Huerta-Cepas, Jaime; Cottret, Ludovic; Febvay, Gérard; Calevro, Federica; Rahbé, Yvan; Douglas, Angela E; Gabaldón, Toni; Sagot, Marie-France; Charles, Hubert; Colella, Stefano

    2011-01-01

    In recent years, genomes from an increasing number of organisms have been sequenced, but their annotation remains a time-consuming process. The BioCyc databases offer a framework for the integrated analysis of metabolic networks. The Pathway tool software suite allows the automated construction of a database starting from an annotated genome, but it requires prior integration of all annotations into a specific summary file or into a GenBank file. To allow the easy creation and update of a BioCyc database starting from the multiple genome annotation resources available over time, we have developed an ad hoc data management system that we called Cyc Annotation Database System (CycADS). CycADS is centred on a specific database model and on a set of Java programs to import, filter and export relevant information. Data from GenBank and other annotation sources (including for example: KAAS, PRIAM, Blast2GO and PhylomeDB) are collected into a database to be subsequently filtered and extracted to generate a complete annotation file. This file is then used to build an enriched BioCyc database using the PathoLogic program of Pathway Tools. The CycADS pipeline for annotation management was used to build the AcypiCyc database for the pea aphid (Acyrthosiphon pisum) whose genome was recently sequenced. The AcypiCyc database webpage includes also, for comparative analyses, two other metabolic reconstruction BioCyc databases generated using CycADS: TricaCyc for Tribolium castaneum and DromeCyc for Drosophila melanogaster. Linked to its flexible design, CycADS offers a powerful software tool for the generation and regular updating of enriched BioCyc databases. The CycADS system is particularly suited for metabolic gene annotation and network reconstruction in newly sequenced genomes. Because of the uniform annotation used for metabolic network reconstruction, CycADS is particularly useful for comparative analysis of the metabolism of different organisms. Database URL: http://www.cycadsys.org.

  3. Ontogenetic resource-use strategies in a rare long-lived cycad along environmental gradients.

    Science.gov (United States)

    Álvarez-Yépiz, Juan C; Cueva, Alejandro; Dovčiak, Martin; Teece, Mark; Yepez, Enrico A

    2014-01-01

    Functional traits can drive plant responses to short- and long-term stressful conditions, with potential effects on species persistence in local habitats, changes in population size and structure, and potential species range shifts in changing environments. We investigated whether ecophysiological traits in a rare cycad vary along environmental gradients and with ontogeny to understand intra-specific resource-use variation (e.g. symbiotic nitrogen fixation, nitrogen- and water-use efficiency) and possible species adaptations for different environments. Environmental gradients were characterized with 14 soil and topographic variables. Nitrogen- and water-use efficiency improved with ontogeny (from seedling to juvenile and adult stages) but declined as soil fertility decreased with increasing elevation. Conversely, reliance on symbiotic nitrogen fixation increased with elevation and varied slightly with ontogeny. Improved water-use efficiency at lower elevation and nitrogen fixation at higher elevation may represent key functional strategies for maintaining the lower and upper altitudinal species range limits, especially in arid environments where stressful conditions are intensifying due to climatic and land-use changes. In addition to facilitation linked to the regeneration niche, improved resource-use efficiency linked to the adult niche may strongly influence cycad distribution and persistence in contemporary environments. A functional approach to conservation of rare or endangered plant species may be needed in order to target the most sensitive stages to changing environmental conditions and to better understand potential range shifts and adaptive responses to global land-use and climate changes.

  4. Transcriptome-derived microsatellite markers for Dioon (Zamiaceae) cycad species1

    Science.gov (United States)

    Prado, Alberto; Cervantes-Díaz, Fret; Perez-Zavala, Francisco G.; González-Astorga, Jorge; Bede, Jacqueline C.; Cibrián-Jaramillo, Angélica

    2016-01-01

    Premise of the study: Dioon (Zamiaceae) is an endangered North American cycad genus of evolutionary and ornamental value. We designed and validated a set of microsatellite markers from D. edule that can be used for population-level and conservation studies, and that transferred successfully to D. angustifolium, D. spinulosum, and D. holmgrenii. Methods and Results: We tested 50 primers from 80 microsatellite candidate loci in the OneKP D. edule transcriptome. Genotypes from 21 loci in 20 D. edule individuals revealed up to 14 alleles per locus and observed heterozygosity from 0.15 to 0.92; one locus was monomorphic. Seven of those 21 loci were polymorphic in D. angustifolium, D. spinulosum, and D. holmgrenii, with up to seven alleles, and an observed heterozygosity up to 0.89. Conclusions: The transcriptome-derived microsatellites generated here will serve as tools to advance population genetic studies and inform conservation strategies of Dioon, including the identification and origin of illegal plants in the cycad trade. PMID:26949574

  5. Experimental evaluation and thermo-physical analysis of thermogenesis in male and female cycad cones.

    Science.gov (United States)

    Roemer, Robert; Terry, Irene; Chockley, Christina; Jacobsen, Jennifer

    2005-06-01

    Thermogenically elevated cone temperatures were measured in two Macrozamia cycad species that differ in their daily heating time. Mathematical models of the cones' thermo-physics were tested for their accuracy in predicting these cone temperatures and for comparison of the energetics of both species and the sexes within species. These models accurately predicted temperatures over approximately 8-h periods with average errors of: 0.46 degrees C for Macrozamia lucida, pollinated by the thrips, Cycadothrips chadwicki, that moves during mid-day concurrent with cone heating; and 0.38 degrees C for Macrozamia machinii, pollinated by the weevil, Tranes sp., that moves after sunset during cone heating. The combination of models and experiments revealed a thermogenic sexual dimorphism in both species. For M. lucida, the estimated female mass specific metabolisms, and their theoretically possible and actual temperature increases due to thermogenic metabolism were only 57, 67, and 76% of males. In addition, female thermogenic metabolisms began and peaked much earlier and lasted significantly longer than males (all differences >1 h), and female metabolic peaks preceded their temperature peaks by 65 vs. 46 min for males. The timing of almost all male cone metabolic peaks was optimized with respect to the diurnal ambient heating cycle so that cone temperatures achieved a maximum temperature gain, whereas most female metabolic peaks occurred much earlier than optimal. In M. machinii, thermogenic sexual dimorphism is much larger since its male peak metabolisms are larger, and its females' peaks are much smaller compared to those of M. lucida. This study provides new information regarding the energetics of cycad cones that is relevant to understanding the interactions of the plant traits with their obligate pollinators' behavior.

  6. Host Response of Ornamental Palms to Rotylenchulus reniformis.

    Science.gov (United States)

    Inserra, R N; Dunn, R A; Vovlas, N

    1994-12-01

    The responses of 20 species of ornamental palms and one cycad (Cycas revoluta) to two populations of the reniform nematode, Rotylenchulus reniformis, from southern Florida were studied in two greenhouse experiments conducted in 1989-1991 and 1991-92. Ornamental palms in pots were exposed to initial population densities of 400 and 1,500 R. reniformis/l00 cm(3) soil for 16 and 15 months, respectively. Nematode reproduction occurred on Acoelorrhaphe wrightii and Washingtonia robusta, but not on the other palms or the cycad. In both experiments, nematode numbers on A. wrightii and W. robusta were significantly smaller than those on cowpea (Vigna unguiculata), a susceptible host of the nematode used as a control in these experiments. Nematodes surviving in pots containing nonhost palms for 16 months retained infectivity and were able to reproduce on susceptible cowpea in a bioassay. Sections from Washingtonia robusta roots infected by R. reniformis females showed the nematode feeding on syncytia formed by endodermal, pericyclic, and vascular parenchyma cells in a manner similar to that reported for other monocot hosts of the reniform nematode.

  7. OSD1 promotes meiotic progression via APC/C inhibition and forms a regulatory network with TDM and CYCA1;2/TAM.

    Directory of Open Access Journals (Sweden)

    Laurence Cromer

    Full Text Available Cell cycle control is modified at meiosis compared to mitosis, because two divisions follow a single DNA replication event. Cyclin-dependent kinases (CDKs promote progression through both meiosis and mitosis, and a central regulator of their activity is the APC/C (Anaphase Promoting Complex/Cyclosome that is especially required for exit from mitosis. We have shown previously that OSD1 is involved in entry into both meiosis I and meiosis II in Arabidopsis thaliana; however, the molecular mechanism by which OSD1 controls these transitions has remained unclear. Here we show that OSD1 promotes meiotic progression through APC/C inhibition. Next, we explored the functional relationships between OSD1 and the genes known to control meiotic cell cycle transitions in Arabidopsis. Like osd1, cyca1;2/tam mutation leads to a premature exit from meiosis after the first division, while tdm mutants perform an aberrant third meiotic division after normal meiosis I and II. Remarkably, while tdm is epistatic to tam, osd1 is epistatic to tdm. We further show that the expression of a non-destructible CYCA1;2/TAM provokes, like tdm, the entry into a third meiotic division. Finally, we show that CYCA1;2/TAM forms an active complex with CDKA;1 that can phosphorylate OSD1 in vitro. We thus propose that a functional network composed of OSD1, CYCA1;2/TAM, and TDM controls three key steps of meiotic progression, in which OSD1 is a meiotic APC/C inhibitor.

  8. 堆芯核设计程序CYCAS动力学模型开发%Development of Kinetics Model in Core Nuclear Design Code CYCAS

    Institute of Scientific and Technical Information of China (English)

    毕光文; 汤春桃; 杨波

    2016-01-01

    The kinetics model and its numerical verification were studied for core nuclear design code CYCAS .The kinetics model employed by CYCAS code was introduced in detail .In order to verify the effectiveness of the kinetics model , the L M W transient benchmark and the dynamic insertion issue of control rod in AP1000 core were simulated and analyzed .The calculation results show that the kinetics model of CYCAS code could obtain reliable results .%对堆芯核设计程序CYCAS的动力学模型及其数值验证进行了研究.详细介绍了CYCAS程序采用的动力学模型.为验证模型的有效性,对L M W瞬态基准题和基于AP1000堆芯动态插棒问题进行了数值模拟和分析.结果表明,CYCAS程序的动力学模型可获得可靠的计算结果.

  9. Origin and diversification of living cycads: a cautionary tale on the impact of the branching process prior in Bayesian molecular dating.

    Science.gov (United States)

    Condamine, Fabien L; Nagalingum, Nathalie S; Marshall, Charles R; Morlon, Hélène

    2015-04-17

    Bayesian relaxed-clock dating has significantly influenced our understanding of the timeline of biotic evolution. This approach requires the use of priors on the branching process, yet little is known about their impact on divergence time estimates. We investigated the effect of branching priors using the iconic cycads. We conducted phylogenetic estimations for 237 cycad species using three genes and two calibration strategies incorporating up to six fossil constraints to (i) test the impact of two different branching process priors on age estimates, (ii) assess which branching prior better fits the data, (iii) investigate branching prior impacts on diversification analyses, and (iv) provide insights into the diversification history of cycads. Using Bayes factors, we compared divergence time estimates and the inferred dynamics of diversification when using Yule versus birth-death priors. Bayes factors were calculated with marginal likelihood estimated with stepping-stone sampling. We found striking differences in age estimates and diversification dynamics depending on prior choice. Dating with the Yule prior suggested that extant cycad genera diversified in the Paleogene and with two diversification rate shifts. In contrast, dating with the birth-death prior yielded Neogene diversifications, and four rate shifts, one for each of the four richest genera. Nonetheless, dating with the two priors provided similar age estimates for the divergence of cycads from Ginkgo (Carboniferous) and their crown age (Permian). Of these, Bayes factors clearly supported the birth-death prior. These results suggest the choice of the branching process prior can have a drastic influence on our understanding of evolutionary radiations. Therefore, all dating analyses must involve a model selection process using Bayes factors to select between a Yule or birth-death prior, in particular on ancient clades with a potential pattern of high extinction. We also provide new insights into the

  10. Green synthesis and characterization of silver nanoparticles by leaf extracts of Cycas circinalis, Ficus amplissima, Commelina benghalensis and Lippia nodiflora

    Science.gov (United States)

    Johnson, I.; Prabu, H. Joy

    2015-01-01

    Biosynthesis of nanoparticles is a kind of bottom-up approach where the main reaction occurring is reduction. Since silver nanoparticles (AgNPs) have been used for infection prevention in medical field, it is more relevant to reduce their size using ancient Indian herbal plants. This method is good in anti-microbial efficiency against bacteria, viruses and other microorganisms and hence clearly enhances the medicinal usage of AgNPs. This type of green biosynthesis of nanoparticles has received increasing attention due to the growing need to develop safe, cost-effective and environmental-friendly technologies for nano-materials synthesis. In the process of synthesizing AgNPs, we observed a rapid reduction of silver ions leading to the formation of stable crystalline AgNPs in the solution. Plant extracts from Cycas circinalis, Ficus amplissima, Commelina benghalensis and Lippia nodiflora were used for the synthesis of AgNPs from silver nitrate solution. AgNPs were characterized by different techniques.

  11. Mathematical model of cycad cones' thermogenic temperature responses: inverse calorimetry to estimate metabolic heating rates.

    Science.gov (United States)

    Roemer, R B; Booth, D; Bhavsar, A A; Walter, G H; Terry, L I

    2012-12-21

    A mathematical model based on conservation of energy has been developed and used to simulate the temperature responses of cones of the Australian cycads Macrozamia lucida and Macrozamia. macleayi during their daily thermogenic cycle. These cones generate diel midday thermogenic temperature increases as large as 12 °C above ambient during their approximately two week pollination period. The cone temperature response model is shown to accurately predict the cones' temperatures over multiple days as based on simulations of experimental results from 28 thermogenic events from 3 different cones, each simulated for either 9 or 10 sequential days. The verified model is then used as the foundation of a new, parameter estimation based technique (termed inverse calorimetry) that estimates the cones' daily metabolic heating rates from temperature measurements alone. The inverse calorimetry technique's predictions of the major features of the cones' thermogenic metabolism compare favorably with the estimates from conventional respirometry (indirect calorimetry). Because the new technique uses only temperature measurements, and does not require measurements of oxygen consumption, it provides a simple, inexpensive and portable complement to conventional respirometry for estimating metabolic heating rates. It thus provides an additional tool to facilitate field and laboratory investigations of the bio-physics of thermogenic plants. Copyright © 2012 Elsevier Ltd. All rights reserved.

  12. Carotenoid composition and its chemotaxonomic significance in leaves of ten species of the genus Ceratozamia (Cycads).

    Science.gov (United States)

    Cardinif, Franco; Bonzi, Laura Morassi

    2005-05-01

    The qualitative composition and localization of carotenoids in leaflets of ten species of the genus Ceratozamia (Cycads) was investigated, and the distributions of 16 of these carotenoids, which were isolated and differently located in the chloroplast, are discussed. Eight classic carotenoids are located in the thylakoidal membranes of the chloroplasts of all ten of the species examined. In contrast, eight red keto-carotenoids are unusually located in several plastoglobules present in the stroma of nine species Ceratozamia mexicana Brongn. excluded. The characteristic red-brown transitory coloration shown by the newly formed leaflets during the first stages of development is due to this latter keto mixture. It is constituted of three very rare keto-carotenoids, which were, in our case, identified for the first time from the photosynthetic tissues (semi-beta-carotenone, triphasiaxanthin, and beta-carotenone). It is also constituted of four others, which are completely novel (ceratoxanthin, ceratozamiaxanthin, kuesteriaxanthin, and ceratoxanthone). Some hypotheses about their presence and function are presented.

  13. Thermogenic respiratory processes drive the exponential increase of volatile organic compound emissions in Macrozamia cycad cones.

    Science.gov (United States)

    Terry, L Irene; Roemer, Robert B; Booth, David T; Moore, Chris J; Walter, Gimme H

    2016-07-01

    An important outcome of plant thermogenesis is increased emissions of volatiles that mediate pollinator behaviour. We investigated whether the large increase in emissions, mainly the monoterpene ß-myrcene (>90%), during daily thermogenic events of Macrozamia macleayi and lucida cycad cones are due solely to the influence of high cone temperatures or are, instead, a result of increased respiratory rates during thermogenesis. We concurrently measured temperature, oxygen consumption and ß-myrcene emission profiles during thermogenesis of pollen cones under typical environmental temperatures and during experimental manipulations of cone temperatures and aerobic conditions, all in the dark. The exponential rise in ß-myrcene emissions never occurred without a prior, large increase in respiration, whereas an increase in cone temperature alone did not increase emissions. When respiration during thermogenesis was interrupted by anoxic conditions, ß-myrcene emissions decreased. The increased emission rates are not a result of increased cone temperature per se (through increased enzyme activity or volatilization of stored volatiles) but are dependent on biosynthetic pathways associated with increased respiration during thermogenesis that provide the carbon, energy (ATP) and reducing compounds (NADPH) required for ß-myrcene production through the methylerythritol phosphate (MEP) pathway. These findings establish the significant contribution of respiration to volatile production during thermogenesis.

  14. Unraveling 50-Year-Old Clues Linking Neurodegeneration and Cancer to Cycad Toxins: Are microRNAs Common Mediators?

    Science.gov (United States)

    Spencer, Peter; Fry, Rebecca C; Kisby, Glen E

    2012-01-01

    Recognition of overlapping molecular signaling activated by a chemical trigger of cancer and neurodegeneration is new, but the path to this discovery has been long and potholed. Six conferences (1962-1972) examined the puzzling neurotoxic and carcinogenic properties of a then-novel toxin [cycasin: methylazoxymethanol (MAM)-β-d-glucoside] in cycad plants used traditionally for food and medicine on Guam where a complex neurodegenerative disease plagued the indigenous population. Affected families showed combinations of amyotrophic lateral sclerosis (ALS), parkinsonism (P), and/or a dementia (D) akin to Alzheimer's disease (AD). Modernization saw declining disease rates on Guam and remarkable changes in clinical phenotype (ALS was replaced by P-D and then by D) and in two genetically distinct ALS-PDC-affected populations (Kii-Japan, West Papua-Indonesia) that used cycad seed medicinally. MAM forms DNA lesions - repaired by O(6)-methylguanine methyltransferase (MGMT) - that perturb mouse brain development and induce malignant tumors in peripheral organs. The brains of young adult MGMT-deficient mice given a single dose of MAM show DNA lesion-linked changes in cell-signaling pathways associated with miRNA-1, which is implicated in colon, liver, and prostate cancers, and in neurological disease, notably AD. MAM is metabolized to formaldehyde, a human carcinogen. Formaldehyde-responsive miRNAs predicted to modulate MAM-associated genes in the brains of MGMT-deficient mice include miR-17-5p and miR-18d, which regulate genes involved in tumor suppression, DNA repair, amyloid deposition, and neurotransmission. These findings marry cycad-associated ALS-PDC with colon, liver, and prostate cancer; they also add to evidence linking changes in microRNA status both to ALS, AD, and parkinsonism, and to cancer initiation and progression.

  15. Unraveling 50-year-old clues linking neurodegeneration and cancer to cycad toxins: are microRNAs a common mediator?

    Directory of Open Access Journals (Sweden)

    Peter eSpencer

    2012-09-01

    Full Text Available Recognition of overlapping molecular signaling activated by a chemical trigger of cancer and neurodegeneration is new, but the path to this discovery has been long and potholed. Six conferences (1962-1972 examined the puzzling neurotoxic and carcinogenic properties of a then-novel toxin [cycasin: methylazoxymethanol (MAM-β-D-glucoside] in cycad plants used traditionally for food and medicine on Guam where a complex neurodegenerative disease plagued the indigenous population. Affected families showed combinations of amyotrophic lateral sclerosis (ALS, parkinsonism (P and/or a dementia (D akin to Alzheimer’s disease (AD. Modernization saw declining disease rates on Guam and remarkable changes in clinical phenotype (ALS was replaced by P-D and then by D and in two genetically distinct ALS-PDC-affected populations (Kii-Japan, West Papua-Indonesia that used cycad seed medicinally. MAM forms DNA lesions -- repaired by O6-methylguanine methyltransferase (MGMT -- that perturb mouse brain development and induce malignant tumors in peripheral organs. The brains of young adult MGMT-deficient mice given a single dose of MAM show DNA lesion-linked changes in cell signaling pathways associated with miRNA-1, which is implicated in colon, liver and prostate cancers, and in neurological disease, notably AD. MAM is metabolized to formaldehyde, a human carcinogen. Formaldehyde-responsive miRNAs predicted to modulate MAM-associated genes in the brains of MGMT-deficient mice include miR-17-5p and miR-18d, which regulate genes involved in tumor suppression, DNA repair, amyloid deposition, and neurotransmission. These findings marry cycad-associated ALS-PDC with colon, liver and prostate cancer; they also add to evidence linking changes in microRNA status both to ALS, AD, and parkinsonism, and to cancer initiation and progression.

  16. Caterpillars of Eumaeus childrenae (Lepidoptera: Lycaenidae) feeding on two species of cycads (Zamiaceae) in the Huasteca region, Mexico

    OpenAIRE

    Raúl Contreras-Medina; Ruiz-Jiménez, Carlos A; Isolda Luna Vega

    2003-01-01

    There are few genera of butterflies that feed on cycads. Among them the genus Eumaeus (Lycaenidae) presents aposematic coloration in all its life stages. In this work we report for the first time the herbivory of young leaflets of Ceratozamia mexicana and Zamia fischeri (Zamiaceae) by caterpillars of E. childrenae in their natural habitat in the Huasteca region, Mexico.Muy pocos géneros de mariposas se alimentan de cícadas. Entre ellos, el género Fumaeus (Lycaenidae) presenta coloración apose...

  17. Caterpillars of Eumaeus childrenae (Lepidoptera: Lycaenidae) feeding on two species of cycads (Zamiaceae) in the Huasteca region, Mexico

    OpenAIRE

    Contreras-Medina, Raúl; Ruiz-Jiménez, Carlos A; Luna Vega, Isolda

    2014-01-01

    There are few genera of butterflies that feed on cycads. Among them the genus Eumaeus (Lycaenidae) presents aposematic coloration in all its life stages. In this work we report for the first time the herbivory of young leaflets of Ceratozamia mexicana and Zamia fischeri (Zamiaceae) by caterpillars of E. childrenae in their natural habitat in the Huasteca region, Mexico. Muy pocos géneros de mariposas se alimentan de cícadas. Entre ellos, el género Fumaeus (Lycaenidae) presenta coloración a...

  18. IDENTIFICATION OF MAJALAYA COMMON CARP STRAINS RESISTANT TO KHV INFECTION USING CYCA-DAB1*05 ALLELE AS THE MARKER

    Directory of Open Access Journals (Sweden)

    Alimuddin Alimuddin

    2011-12-01

    Full Text Available The Cyca-DAB1*05 allele of major histocompatibility complex class II genes is recently suggested to have a link with the European common carp strain resistant to koi herpesvirus (KHV. In this study, a set of specific primers for Cyca-DAB1*05 was designed and applied as a marker to identify broodstocks of majalaya common carp strain subsequently used as a candidate resistant to KHV infection. From a total of 23 broodstock subjected to PCR analysis, two female and male fish, both having (P and no Cyca-DAB1*05 (N, were selected and then diallelly mated. Disease resistance of progenies from 10 crosses was determined by a survival analysis in pond rearing and a laboratory challenge-test using cohabitation method. The results have revealed that the average survivals of PxP progenies for pond rearing and KHV challenge test were 86% and 100% higher (P < 0.05 respectively compared to that of NxN fish. Survival rate of PxN/NxP progenies was significantly lower (P < 0.05 than that of PxP fish. Furthermore, PCR analysis showed that almost 91% progenies of PxP crosses seemed to have a KHV resistant gene marker. Thus, this study suggests that the marker is associated with the KHV resistance in majalaya common carp strain, and farming of PxP progenies can be useful to increase common carp production.

  19. Discovery of a new sub-population, mapping and updated Red List assessment of the Endangered Cycas beddomei Dyer (Cycadales: Cycadaceae

    Directory of Open Access Journals (Sweden)

    B. Ravi Prasad Rao

    2015-10-01

    Full Text Available A new sub-population of Cycas beddomei Dyer (Cycadaceae, hitherto believed to be endemic to the Seshachalam Hills (Tirupati-Kadapa Hills of Andhra Pradesh is discovered from Velikonda Hills (Nellore-Kadapa districts of Andhra Pradesh.  Hence its global distribution status is hereby revised endemic to Seshachalam and Velikonda hills  of Eastern Ghats of Andhra Pradesh.  Combined datasets of our earlier studies with the latest indicated no change in its ‘Endangered’ status.  

  20. 攀枝花苏铁人工繁育初探%Discuss Breed Cycad Artificially

    Institute of Scientific and Technical Information of China (English)

    余志祥; 杨永琼

    2004-01-01

    苏铁植物(Cycas)是与恐龙同时代的植物,素有植物活化石之称,是地球上现存最为古老的孑遗植物之一,为国家Ⅰ级重点保护植物、(CITES)附录Ⅱ保护物种.苏铁植物对研究古地理的变迁、生物的演化有着重要的意义,作为珍稀古老特种基因包含了丰富的遗传信息,现代广泛应用于地质勘探和园林珍贵花卉,并显示出巨大的潜在药物开发价值.受自然条件约束及不法分子危害等原因,苏铁植物自然资源正逐渐减少.攀枝花苏铁自然保护区管理处工作人员在不断观察、研究的基础上,对攀枝花苏铁进行了人工授粉、采种、种子储藏、育苗等工作,培育了攀枝花苏铁幼苗5万余株,在攀枝花苏铁人工繁育方面取得了一定经验.

  1. Nesting behaviour of the Baya Weaver bird, Ploceus philippinus (Ploceidae and the life-cycle of the Plains Cupid butterfly, Chilades pandava (Lycaenidae with the red-listed Cycas spheric and C. beddomei (Cycadaceae

    Directory of Open Access Journals (Sweden)

    A.J.S. Raju

    2009-08-01

    Full Text Available The Baya Weaver bird, Ploceus philippinus utilizes the well developed leaves of Cycas sphaerica for nest construction and offspring production. It constructs nest on the leaf tips of this species; the nest material used is exclusively Dendrocalamus strictus. This bird species does not utilize Cycas beddomei for nest construction and offspring production. The Plains Cupid butterfly, Chilades pandava utilizes the newly emerging leaves of both C. sphaerica and C. beddomei for raising its offspring. In both the Cycas species, the new leaves emerge as a crown at the top of the plant; the larvae of C. pandava feed on these leaves and make the plant as leafless until the next leaf flushing season. New leaf production occurs after coning event in Cycas species; coning is not annual event. In consequence, the plants utilized by C. pandava for the production of its offspring remain leafless until the next coning season and their survival during this period depends on the nutrient status within the shoot system and in the soil system. The study suggests that there is no direct or indirect interaction between C. pandava and P. philippinus. C. sphaerica serves as a host plant for these two animal species at different times; but the interaction of these animal species is dependent on the leaves only; C. pandava on newly emerging leaves while P. philippinus on well developed leaves.

  2. 在苏铁类植物中再次发现导管%Discovered Vessel in Cycads Again

    Institute of Scientific and Technical Information of China (English)

    林鉴钊; 黄玉源

    1999-01-01

    本研究对越南蓖齿苏铁(Cycas elonga) 的根进行了观察,发现其次生木质部中具有导管,导管分子横切面观为近圆形,侧壁为孔纹纹饰,具缘纹孔,端壁具一较大的穿孔,为单穿孔板,两相邻导管分子在穿孔处较水平地相连接.端壁常具尾尖;每个导管分子长度较大.这是继鳞秕泽米铁中发现导管之后再次在苏铁类植物中发现导管.这对于系统与演化植物学和结构植物学等方面具有着重大的意义.

  3. Caterpillars of Eumaeus childrenae (Lepidoptera: Lycaenidae feeding on two species of cycads (Zamiaceae in the Huasteca region, Mexico

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    Raúl Contreras-Medina

    2003-03-01

    Full Text Available There are few genera of butterflies that feed on cycads. Among them the genus Eumaeus (Lycaenidae presents aposematic coloration in all its life stages. In this work we report for the first time the herbivory of young leaflets of Ceratozamia mexicana and Zamia fischeri (Zamiaceae by caterpillars of E. childrenae in their natural habitat in the Huasteca region, Mexico.Muy pocos géneros de mariposas se alimentan de cícadas. Entre ellos, el género Fumaeus (Lycaenidae presenta coloración aposemática en todos sus estadíos de vida. En este trabajo informamos por primera vez la herbivoría de folíolos jóvenes de Ceratozamia mexicana y Zamia fischeri (Zamiacecae por orugas de E. childrenae en su hábitat natural en la región Huasteca, México.

  4. Development of cycad ovules and seeds. 2. Histological and ultrastructural aspects of ontogeny of the embryo in Encephalartos natalensis (Zamiaceae).

    Science.gov (United States)

    Woodenberg, Wynston Ray; Berjak, Patricia; Pammenter, N W; Farrant, Jill M

    2014-07-01

    Development of the embryo of Encephalartos natalensis from a rudimentary meristematic structure approximately 700 μm in length extends over 6 months after the seed is shed from the strobilus. Throughout its development, the embryo remains attached to a long suspensor. Differentiation of the shoot meristem flanked by two cotyledonary protuberances occurs over the first 2 months, during which peripheral tannin channels become apparent. Tannins, apparently elaborated by the endoplasmic reticulum, first accumulate in the large central vacuole and ultimately fill the channel. By the fourth month of development, the root meristem is apparent and procambial tissue forming discrete vascular bundles can be discerned in the elongating cotyledons. Between 4 and 6 months, mucilage ducts differentiate; after 6 months, when the seed becomes germinable, the embryo is characterised by cotyledons far longer than the axis. Shoot and root meristem cells remain ultrastructurally similar throughout embryo ontogeny, containing small vacuoles, many well-differentiated mitochondria and endoplasmic reticulum (ER) profiles, abundant polysomes, plastids containing small starch deposits and Golgi bodies. Unusually, however, Golgi bodies are infrequent in other cells including those elaborating mucilage which is accumulated in distended ER and apparently secreted into the duct lumen directly by ER-derived vesicles. The non-meristematic cells accumulate massive starch deposits to the exclusion of any protein bodies and only very sparse lipid, features which are considered in terms of the prolonged period of embryo development and the high atmospheric oxygen content of the Carboniferous Period, when cycads are suggested to have originated.

  5. In vitro effects of cholesterol β-D-glucoside, cholesterol and cycad phytosterol glucosides on respiration and reactive oxygen species generation in brain mitochondria.

    Science.gov (United States)

    Panov, Alexander; Kubalik, Nataliya; Brooks, Benjamin R; Shaw, Christopher A

    2010-10-01

    The cluster of neurodegenerative disorders in the western Pacific termed amyotrophic lateral sclerosis-parkinsonism dementia complex (ALS-PDC) has been repeatedly linked to the use of seeds of various species of cycad. Identification and chemical synthesis of the most toxic compounds in the washed cycad seeds, a variant phytosteryl glucosides, and even more toxic cholesterol β-D-glucoside (CG), which is produced by the human parasite Helicobacter pylori, provide a possibility to study in vitro the mechanisms of toxicity of these compounds. We studied in detail the effects of CG on the respiratory activities and generation of reactive oxygen species (ROS) by nonsynaptic brain and heart mitochondria oxidizing various substrates. The stimulatory effects of CG on respiration and ROS generation showed strong substrate dependence, suggesting involvement of succinate dehydrogenase (complex II). Maximal effects on ROS production were observed with 1 μmol CG/1 mg mitochondria. At this concentration the cycad toxins β-sitosterol-β-D-glucoside and stigmasterol-β-D-glucoside had effects on respiration and ROS production similar to CG. However, poor solubility precluded full concentration analysis of these toxins. Cholesterol, stigmasterol and β-sitosterol had no effect on mitochondrial functions studied at concentrations up to 100 μmol/mg protein. Our results suggest that CG may influence mitochondrial functions through changes in the packing of the bulk membrane lipids, as was shown earlier by Deliconstantinos et al. (Biochem Cell Biol 67:16-24, 1989). The neurotoxic effects of phytosteryl glucosides and CG may be associated with increased oxidative damage of neurons. Unlike heart mitochondria, in activated neurons mitochondria specifically increase ROS production associated with succinate oxidation (Panov et al., J Biol Chem 284:14448-14456, 2009).

  6. Return of the cycad hypothesis - does the amyotrophic lateral sclerosis/parkinsonism dementia complex (ALS/PDC) of Guam have new implications for global health?

    Science.gov (United States)

    Ince, P G; Codd, G A

    2005-08-01

    Recently published work provides evidence in support of the cycad hypothesis for Lytico--Bodig, the Guamanian amyotrophic lateral sclerosis/parkinsonism dementia complex (ALS/PDC), based on a new understanding of Chamorro food practices, a cyanobacterial origin of beta-methylaminoalanine (BMAA) in cycad tissue, and a possible mechanism of biomagnification of this neurotoxic amino acid in the food chain. BMAA is one of two cycad chemicals with known neurotoxic properties (the other is cycasin, a proven developmental neurotoxin) among the many substances that exist in these highly poisonous plants, the seeds of which are used by Chamorros for food and medicine. The traditional diet includes the fruit bat, a species that feeds on cycad seed components and reportedly bioaccumulates BMAA. Plant and animal proteins provide a previously unrecognized reservoir for the slow release of this toxin. BMAA is reported in the brain tissue of Guam patients and early data suggest that some Northern American patients dying of Alzheimer's disease (AD) have detectable brain levels of BMAA. The possible role of cyanobacterial toxicity in sporadic neurodegenerative disease is therefore worthy of consideration. Recent neuropathology studies of ALS/PDC confirm understanding of this disorder as a 'tangle' disease, based on variable anatomical burden, and showing biochemical characteristics of 'AD-like' combined 3R and 4R tau species. This model mirrors the emerging view that other neurodegenerative disease spectra comprise clusters of related syndromes, owing to common molecular pathology, with variable anatomical distribution in the nervous system giving rise to different clinical phenotypes. Evidence for 'ubiquitin-only' inclusions in ALS/PDC is weak. Similarly, although there is evidence for alpha-synucleinopathy in ALS/PDC, the parkinsonian component of the disease is not caused by Lewy body disease. The spectrum of sporadic AD includes involvement of the substantia nigra and a high

  7. The cycad genotoxin MAM modulates brain cellular pathways involved in neurodegenerative disease and cancer in a DNA damage-linked manner.

    Directory of Open Access Journals (Sweden)

    Glen E Kisby

    Full Text Available Methylazoxymethanol (MAM, the genotoxic metabolite of the cycad azoxyglucoside cycasin, induces genetic alterations in bacteria, yeast, plants, insects and mammalian cells, but adult nerve cells are thought to be unaffected. We show that the brains of adult C57BL6 wild-type mice treated with a single systemic dose of MAM acetate display DNA damage (O⁶-methyldeoxyguanosine lesions, O⁶-mG that remains constant up to 7 days post-treatment. By contrast, MAM-treated mice lacking a functional gene encoding the DNA repair enzyme O⁶-mG DNA methyltransferase (MGMT showed elevated O⁶-mG DNA damage starting at 48 hours post-treatment. The DNA damage was linked to changes in the expression of genes in cell-signaling pathways associated with cancer, human neurodegenerative disease, and neurodevelopmental disorders. These data are consistent with the established developmental neurotoxic and carcinogenic properties of MAM in rodents. They also support the hypothesis that early-life exposure to MAM-glucoside (cycasin has an etiological association with a declining, prototypical neurodegenerative disease seen in Guam, Japan, and New Guinea populations that formerly used the neurotoxic cycad plant for food or medicine, or both. These findings suggest environmental genotoxins, specifically MAM, target common pathways involved in neurodegeneration and cancer, the outcome depending on whether the cell can divide (cancer or not (neurodegeneration. Exposure to MAM-related environmental genotoxins may have relevance to the etiology of related tauopathies, notably, Alzheimer's disease.

  8. The cycad genotoxin MAM modulates brain cellular pathways involved in neurodegenerative disease and cancer in a DNA damage-linked manner.

    Science.gov (United States)

    Kisby, Glen E; Fry, Rebecca C; Lasarev, Michael R; Bammler, Theodor K; Beyer, Richard P; Churchwell, Mona; Doerge, Daniel R; Meira, Lisiane B; Palmer, Valerie S; Ramos-Crawford, Ana-Luiza; Ren, Xuefeng; Sullivan, Robert C; Kavanagh, Terrance J; Samson, Leona D; Zarbl, Helmut; Spencer, Peter S

    2011-01-01

    Methylazoxymethanol (MAM), the genotoxic metabolite of the cycad azoxyglucoside cycasin, induces genetic alterations in bacteria, yeast, plants, insects and mammalian cells, but adult nerve cells are thought to be unaffected. We show that the brains of adult C57BL6 wild-type mice treated with a single systemic dose of MAM acetate display DNA damage (O⁶-methyldeoxyguanosine lesions, O⁶-mG) that remains constant up to 7 days post-treatment. By contrast, MAM-treated mice lacking a functional gene encoding the DNA repair enzyme O⁶-mG DNA methyltransferase (MGMT) showed elevated O⁶-mG DNA damage starting at 48 hours post-treatment. The DNA damage was linked to changes in the expression of genes in cell-signaling pathways associated with cancer, human neurodegenerative disease, and neurodevelopmental disorders. These data are consistent with the established developmental neurotoxic and carcinogenic properties of MAM in rodents. They also support the hypothesis that early-life exposure to MAM-glucoside (cycasin) has an etiological association with a declining, prototypical neurodegenerative disease seen in Guam, Japan, and New Guinea populations that formerly used the neurotoxic cycad plant for food or medicine, or both. These findings suggest environmental genotoxins, specifically MAM, target common pathways involved in neurodegeneration and cancer, the outcome depending on whether the cell can divide (cancer) or not (neurodegeneration). Exposure to MAM-related environmental genotoxins may have relevance to the etiology of related tauopathies, notably, Alzheimer's disease.

  9. Determination of the neurotoxin BMAA (beta-N-methylamino-L-alanine) in cycad seed and cyanobacteria by LC-MS/MS (liquid chromatography tandem mass spectrometry).

    Science.gov (United States)

    Rosén, Johan; Hellenäs, Karl-Erik

    2008-12-01

    A highly specific method for the analysis of beta-N-methylamino-L-alanine (BMAA) by LC-MS/MS (liquid chromatography tandem mass spectrometry) has been developed and applied for cycad seeds and cyanobacteria. BMAA was analysed as a free fraction or as total BMAA after acidic hydrolysis to release any protein-bound BMAA. Deuterium labelled BMAA was synthesised and used as internal standard. The method comprises HILIC (hydrophilic interaction chromatography) and positive electrospray ionisation of the native compound, i.e. no derivatisation was used. For safe identification five specific product ions (m/z 102, 88, 76, 73 and 44), all derived from a precursor ion of m/z 119 and originating from different parts of the molecule, were detected (typical relative abundance 100%, 16%, 14%, 12% and 22% respectively). Cyanobacteria or muscle tissue was spiked with BMAA (10 to 1000 microg g(-1)) to validate the method (accuracy 95% to 109%, relative standard deviation 1% to 6%). The detection limit for free and total BMAA in tissue was cycad seeds, whereas previously reported findings of BMAA in samples of cyanobacteria could not be confirmed. Instead, the presence of alpha-,gamma-diamino butyric acid (DAB), an isomer of BMAA, was confirmed in one sample. The possible implications of this finding are discussed.

  10. Does the cycad genotoxin MAM implicated in Guam ALS-PDC induce disease-relevant changes in mouse brain that includes olfaction?

    Science.gov (United States)

    Kisby, Glen; Palmer, Valerie; Lasarev, Mike; Fry, Rebecca; Iordanov, Mihail; Magun, Eli; Samson, Leona; Spencer, Peter

    2011-11-01

    Western Pacific amyotrophic lateral sclerosis (ALS) and parkinsonism-dementia complex (PDC), a prototypical neurodegenerative disease (tauopathy) affecting distinct genetic groups with common exposure to neurotoxic chemicals in cycad seed, has many features of Parkinson's and Alzheimer's diseases (AD), including early olfactory dysfunction. Guam ALS-PDC incidence correlates with cycad flour content of cycasin and its aglycone methylazoxymethanol (MAM), which produces persistent DNA damage (O(6)-methylguanine) in the brains of mice lacking O(6)-methylguanine methyltransferase (Mgmt(-/-)). We described in Mgmt(-/-)mice up to 7 days post-MAM treatment that brain DNA damage was linked to brain gene expression changes found in human neurological disease, cancer, and skin and hair development. This addendum reports 6 months post-MAM treatment- related brain transcriptional changes as well as elevated mitogen activated protein kinases and increased caspase-3 activity, both of which are involved in tau aggregation and neurofibrillary tangle formation typical of ALS-PDC and AD, plus transcriptional changes in olfactory receptors. Does cycasin act as a "slow (geno)toxin" in ALS-PDC?

  11. Development of Few Group Cross Section Calculation Model for Core Nuclear Design Code CYCAS%堆芯核设计程序CYCAS少群截面模型开发

    Institute of Scientific and Technical Information of China (English)

    杨伟焱; 汤春桃; 毕光文; 杨波

    2016-01-01

    少群截面模型为堆芯三维扩散计算提供实时的节块均匀少群截面,是堆芯计算程序的关键模型之一.CYCAS程序是上海核工程研究设计院最新开发的堆芯三维核设计程序.本文在详细解析影响节块截面的各种因素的基础上,提出应用于CYCAS程序的少群截面的模型.该模型采用能谱修正方法处理由于能谱变化所引入的二次效应,采用微观燃耗修正方法处理燃耗历史效应.单组件和A P1000核电厂的数值验证计算表明,该模型具有很高的计算精度.%The few group cross section calculation model generates node homogeneous few group cross section for core 3D diffusion calculation ,w hich is one of the key models of core calculation code .CYCAS is the new core 3D nuclear design code developed by Shanghai Nuclear Engineering Research & Design Institute (SNERDI) .A new model based on detail analysis of the factors affecting node cross section was developed for CYCAS .In the model ,the energy spectrum correction method was used to process the second order effect introduced by energy spectrum change , and the micro-depletion correction method was utilized to treat depletion history effect .The numerical results of unit assembly and AP1000 core validate the high accuracy of the new model within CYCAS .

  12. Structural observations of Cycas revolute coralloid root and disassociation of endophytic actinomycetes%苏铁珊瑚根结构观察及其内生放线菌分离

    Institute of Scientific and Technical Information of China (English)

    曹妍; 伍建榕

    2012-01-01

    Cycad is the most primitive extant gymnosperms, which is considered to be living fossil. In order to explore the structure and the endophytes actinomycetes of cycad coralloid root, the paraffin section was used to do the observation on microstructure; TWYECM1), Gao one (M2) and Glycerin - asparagine mediums were used to seprate the endophytic actinomycetes in the coralloid roots and through 16S rRNA sequence analysis, the Actinomycetes were identified. The results indicate that the periderm, outer cortex, cyanobacterial zone, internal cortex and vascular cylinder consisted of the cycad coralloid root; the cells of the external and internal cortex presented to be a circular form on the cross section, and pelotons that were stained to be red existed in some cells of them. 13 strains of actionmycetes were separated from the cycad coralloid root through the above three mediums, and they belong to streptomyces and nocardiopsis.%苏铁类是现存最原始的裸子植物类群,被认为是活化石.为了探究清苏铁珊瑚根的结构和内生放线菌的多样性,本研究采用石蜡切片法对苏铁珊瑚根进行显微结构观察,用改良的TWYE (M1)、高氏1号(M2)和甘油—天冬酰胺(M3)培养基对珊瑚根的内生放线菌进行分离,并通过16S rRNA系列分析鉴定其种属.结果表明:苏铁珊瑚根由周皮、外部皮层、藻胞层、内部皮层和维管柱组成;外部皮层和内部皮层细胞在横切面上呈圆形,而且在有的细胞中能看到被染成暗红色的菌丝团的存在;利用以上三种培养基从苏铁珊瑚根中共分离到了13株放线菌,隶属于链霉菌属和拟诺卡氏菌属.

  13. Revision of the New World cycad weevils of the subtribe Allocorynina, with description of two new genera and three new subgenera (Coleoptera: Belidae: Oxycoryninae).

    Science.gov (United States)

    O'brien, Charles W; Tang, William

    2015-06-09

    The taxonomy of the weevils inhabiting male cycad cones in the New World is reviewed. All species belong in a single subtribe, Allocorynina, of the family Belidae, subfamily Oxycoryninae and tribe Oxycorynini and are known to develop only in cones of the cycad genera Dioon and Zamia. Most species of Rhopalotria Chevrolat develop in male cones of Zamia ranging from Mexico, Belize, the Caribbean (Cuba, Isle of Youth, Cayman Islands, Jamaica and the Bahamas) to southern Florida, and one species in those of Dioon spinulosum in Mexico. Rhopalotria consists of three previously described species, two previously described genus-group names (treated herein as subgenera) and four new species described herein: subgenus Allocorynus Sharp with R. calonjei n. sp., R. furfuracea n. sp., R. mollis (Sharp) and R. vovidesi n. sp., and the nominate subgenus Rhopalotria with R. dimidiata Chevrolat, R. meerowi n. sp. and R. slossoni (Schaeffer). The species of Parallocorynus Voss develop only in cones of Dioon in Mexico, and the genus consists of one previously described species, the nominate subgenus and three new subgenera and 11 new species described herein: subgenus Dysicorynus n. subg. with P. andrewsi n. sp. and P. sonorensis n. sp., subgenus Eocorynus n. subg. with P. chemnicki n. sp. and P. schiblii n. sp., subgenus Neocorynus n. subg. with P. iglesiasi n. sp. and P. inexpectatus n. sp., and the nominate subgenus Parallocorynus with P. bicolor (Voss), P. gregoryi n. sp., P. jonesi n. sp., P. norstogi n. sp., P. perezfarrerai n. sp. and P. salasae n. sp. Two new genera are described, Protocorynus with one new species in Honduras, P. bontai, and Notorhopalotria with four new species ranging from Costa Rica to Colombia, N. montgomeryensis, N. panamensis, N. platysoma and N. taylori. Keys to genera, subgenera and species are provided. All of these weevils are believed to be involved in pollination of their host cycads.

  14. The cyclin-A CYCA1;2/TAM is required for the meiosis I to meiosis II transition and cooperates with OSD1 for the prophase to first meiotic division transition.

    Directory of Open Access Journals (Sweden)

    Isabelle d'Erfurth

    2010-06-01

    Full Text Available Meiosis halves the chromosome number because its two divisions follow a single round of DNA replication. This process involves two cell transitions, the transition from prophase to the first meiotic division (meiosis I and the unique meiosis I to meiosis II transition. We show here that the A-type cyclin CYCA1;2/TAM plays a major role in both transitions in Arabidopsis. A series of tam mutants failed to enter meiosis II and thus produced diploid spores and functional diploid gametes. These diploid gametes had a recombined genotype produced through the single meiosis I division. In addition, by combining the tam-2 mutation with AtSpo11-1 and Atrec8, we obtained plants producing diploid gametes through a mitotic-like division that were genetically identical to their parents. Thus tam alleles displayed phenotypes very similar to that of the previously described osd1 mutant. Combining tam and osd1 mutations leads to a failure in the prophase to meiosis I transition during male meiosis and to the production of tetraploid spores and gametes. This suggests that TAM and OSD1 are involved in the control of both meiotic transitions.

  15. The CYCLIN-A CYCA1;2/TAM Is Required for the Meiosis I to Meiosis II Transition and Cooperates with OSD1 for the Prophase to First Meiotic Division Transition

    Science.gov (United States)

    Jolivet, Sylvie; Girard, Chloé; Horlow, Christine; Sun, Yujin; To, Jennifer P. C.; Berchowitz, Luke E.; Copenhaver, Gregory P.; Mercier, Raphael

    2010-01-01

    Meiosis halves the chromosome number because its two divisions follow a single round of DNA replication. This process involves two cell transitions, the transition from prophase to the first meiotic division (meiosis I) and the unique meiosis I to meiosis II transition. We show here that the A-type cyclin CYCA1;2/TAM plays a major role in both transitions in Arabidopsis. A series of tam mutants failed to enter meiosis II and thus produced diploid spores and functional diploid gametes. These diploid gametes had a recombined genotype produced through the single meiosis I division. In addition, by combining the tam-2 mutation with AtSpo11-1 and Atrec8, we obtained plants producing diploid gametes through a mitotic-like division that were genetically identical to their parents. Thus tam alleles displayed phenotypes very similar to that of the previously described osd1 mutant. Combining tam and osd1 mutations leads to a failure in the prophase to meiosis I transition during male meiosis and to the production of tetraploid spores and gametes. This suggests that TAM and OSD1 are involved in the control of both meiotic transitions. PMID:20585549

  16. 模拟酸雨对德保苏铁叶片光合作用及根系分泌有机酸的影响%Effects of simulated acid rain on photosynthesis of leaves and organic acid secreted by roots of Cycas debaoensis Y.C.Zhong et C.J.Chen

    Institute of Scientific and Technical Information of China (English)

    周明昆; 李正文; 李志刚; 李素丽; 李楠; 刘鹏

    2012-01-01

    [Objective]Effects of acid rain on photosynthesis changes of leaves and organic acid secreted by roots of Cycas debaoensis were studied to better protect Cycas debaoensis. [Method]According to the rainfall characteristics in Guangxi, simulated acid rain spraying was adopted to investigate changes in organic acirl secreted by roots and photosyn-thetic physiology. [Result]Under pH 2.1 acid rain stress, soil pH decreased, the plant leaves showed necrotic lesion, and net photosynthetic rate, stomalal conductance, transpiration rate and the plant intercellular C02 concentration in leaves were all seriously impacted. Oxalic acid was the main organic acid detected from the roots of Cycas debaoensis. The oxalic acid secreted by the roots of Cycas debaoensis showed no change under moderate acid rain stress (pH 4.2 and pH 3.1), but obviously increased under strong acid rain stress(pH 2.1). [Conclusion ]Simulaled acid rain with pH 2.1 severely damaged the leaves of Cycas debaoensis, and weakened their photosynthesis. In response, Cycas debaoensis roots had to secrete more organic acid to adapt and resist overwhelming acid rain stress.%[目的]研究酸雨胁迫下德保苏铁根系分泌有机酸及叶片光合生理变化特征,为德保苏铁的保护提供参考.[方法]针对德保苏铁分布地(广西德保)的降雨特点,采用喷淋模拟酸雨的方法研究土培德保苏铁的根系分泌有机酸和光合生理的变化特征.[结果]在pH 2.1的模拟酸雨胁迫下,土壤pH值降低,德保苏铁叶片出现枯斑,叶片净光合速率、气孔导度、蒸腾速率、胞间CO2浓度均受到严重影响;在德保苏铁根系分泌的有机酸中主要检测出草酸,中强度酸雨(pH 4.2和pH 3.1)对德保苏铁根系分泌草酸的影响不大,而强酸雨(pH 2.1)处理可引起根系分泌草酸含量显著增加.[结论]人工模拟酸雨强度达pH 2.1时对德保苏铁叶片造成严重伤害,其光合作用也随之减弱;德保苏铁根系通过分

  17. Loss-of-function mutants and overexpression lines of the Arabidopsis cyclin CYCA1;2/Tardy Asynchronous Meiosis exhibit different defects in prophase-i meiocytes but produce the same meiotic products.

    Directory of Open Access Journals (Sweden)

    Yixing Wang

    Full Text Available In Arabidopsis, loss-of-function mutations in the A-type cyclin CYCA1;2/Tardy Asynchronous Meiosis (TAM gene lead to the production of abnormal meiotic products including triads and dyads. Here we report that overexpression of TAM by the ASK1:TAM transgene also led to the production of triads and dyads in meiosis, as well as shriveled seeds, in a dominant fashion. However, the partial loss-of-function mutant tam-1, an ASK1:TAM line, and the wild type differed in dynamic changes in chromosome thread thickness from zygotene to diplotene. We also found that the pericentromeric heterochromatin regions in male meiocytes in tam-1 and tam-2 (a null allele frequently formed a tight cluster at the pachytene and diplotene stages, in contrast to the infrequent occurrences of such clusters in the wild type and the ASK1:TAM line. Immunolocalization studies of the chromosome axial component ASY1 revealed that ASY1 was highly expressed at the appropriate male meiotic stages but not localized to the chromosomes in tam-2. The level of ASY1, however, was greatly reduced in another ASK1:TAM line with much overexpressed TAM. Our results indicate that the reduction and increase in the activity of TAM differentially affect chromosomal morphology and the action of ASY1 in prophase I. Based on these results, we propose that either the different meiotic defects or a common defect such as missing ASY1 on the chromosomal axes triggers a hitherto uncharacterized cell cycle checkpoint in the male meiocytes in the tam mutants and ASK1:TAM lines, leading to the production of the same abnormal meiotic products.

  18. Comparative Anatomic Studies on Rachis of Eight Species of Cycads%八种苏铁植物叶轴的比较解剖研究

    Institute of Scientific and Technical Information of China (English)

    伍映辉; 黄玉源; 艾素云; 韦丽君

    2007-01-01

    对苏铁科和泽米铁科8种苏铁植物,即台湾苏铁(Cycas taiwaniana)、海南苏铁(C.hainanensis)、元江苏铁(C.parvulus)、单羽苏铁(C.simplicipinna)、滇南苏铁(C.diannanensis)、越南篦齿苏铁(C.elongata)、长刺大泽米铁(Macrozamia longispina)、双子铁(Dioon edule)的叶轴横切面结构进行了比较研究,以期为苏铁植物的系统演化和分类进一步提供解剖学依据,并探讨其解剖结构与生态的适应机制.结果表明,较原始的苏铁科和较进化的泽米铁科叶轴的横切面结构无论在表皮、机械组织、基本组织和维管组织,还是在后含物方面都存在着明显的不同;泽米铁科的大泽米铁属与双子铁属差异也较大; 苏铁科科内的6个种则相似性稍大,表明它们是亲缘关系较密切的类群,但每个种都有各自的结构特点.越南篦齿苏铁的维管束排列方式和数目的增加方式与泽米铁科两个种的相似,因此推断它处于较进化的地位.研究还发现苏铁科种类的叶轴的近轴面均像叶片那样具有栅栏组织状同化组织存在.苏铁类植物叶轴具有旱生植物的解剖结构特征:角质层较厚、表皮细胞壁厚、机械组织发达、晶体较多、分泌道和维管束数目较多等结构特征.这些对研究苏铁纲各科及种类之间的进化与亲缘关系提供了佐证,同时揭示了苏铁纲这类古老的植物类群其多个属的种类能够经历如此漫长的地质年代而幸存下来,是由于其在长期演化过程中均形成了这些独特的结构特征,因而具备了相对应的生理功能,能够在恶劣的自然环境下,具备耐干旱、贫瘠、高温及耐盐碱等逆境的结果.

  19. Cycad diversification and tropical biodiversity

    Directory of Open Access Journals (Sweden)

    Rull, V.

    2012-12-01

    Full Text Available The recent unexpected discovery that living Cycadales are not Jurassic-Cretaceous (200– 65 Mya relicts, as all their extant genera began to diversify during the Late Miocene (12 Mya, has challenged a classical evolutionary myth. This brief note shows how this finding may also provide new clues on the shaping of the high tropical biodiversity

    El reciente e inesperado descubrimiento de que las Cycadales actuales no son relictos Jurásico-Cretácicos (200-65 Mya, ya que todos sus géneros iniciaron su diversificación durante el Mioceno Tardío (12 Mya, ha puesto en entredicho un mito evolutivo clásico. En esta nota se expone como este hallazgo puede, además, proporcionar nuevas pistas sobre el origen de la elevada biodiversidad tropical.

  20. Neurotoxic flying foxes as dietary items for the Chamorro people, Marianas Islands.

    Science.gov (United States)

    Banack, Sandra Anne; Murch, Susan J; Cox, Paul Alan

    2006-06-15

    Fanihi -- flying foxes (Pteropus mariannus mariannus, Pteropodidae) -- are a highly salient component of the traditional Chamorro diet. A neurotoxic, non-protein amino acid, beta-methylamino-l-alanine (BMAA) accumulates in flying foxes, which forage on the seeds of Cycas micronesica (Cycadaceae) in Guam's forests. BMAA occurs throughout flying fox tissues both as a free amino acid and in a protein-bound form. It is not destroyed by cooking. Protein-bound BMAA also remains in cycad flour which has been washed and prepared by the Chamorro people as tortillas, dumplings, and thickened soups. Other animals that forage on cycad seeds may also provide BMAA inputs into the traditional Chamorro diet.

  1. SWOT Analysis of Eco-tourism Development in Cycas Panzhihuaensis National Nature Reserves and Development Strategy%攀枝花苏铁国家级自然保护区生态旅游开发SWOT分析及开发策略

    Institute of Scientific and Technical Information of China (English)

    赖启航

    2011-01-01

    The SWOT analysis was applied to the eco-tourism development conditions in Cycas Panzhihuaensis national natural reserves by combinations of quantitative and qualitative. It was concluded that Panzhihua ecological tourism development should take opportunity and advantage strategies and exert their advantages. Some development strategies were proposed, such as following government, reconstructing image, assembling resources, cultivating market, and improving competence so as to build fine, perfect image and overcome disadvantages, balance work and tourism and realize win-win situation%运用定性与定量相结合的方法,对攀枝花苏铁国家级自然保护区生态旅游开发进行了SWOT分析,得出该区生态旅游开发应采取"抓住机遇,乘势发展"的战略,并提出发挥优势、打造精品,完善自身、克服劣势,工旅协调、互促共赢,政府主导、重塑形象,整合资源、培育市场,多方着手、提升竞争力等开发策略.

  2. Induction and multiplication of callus from endosperm of Cycas ...

    African Journals Online (AJOL)

    STORAGESEVER

    2008-12-03

    Dec 3, 2008 ... In the induction studies, 20 µM picloram was the most efficient formulation for .... three treatments, maximum percentage of callus forma- .... Ser. Bot. 45(2): 79-86. Bordallo PN, Silva DH, Maria J, Cruz CD, Fontes EP (2004).

  3. New mite species associated with certain plant species from Guam

    Directory of Open Access Journals (Sweden)

    Gadi V.P. Reddy

    2011-04-01

    Full Text Available Several new mite species have been reported from certain plants from Guam. Most remarkably, the spider mite, Tetranychus marianae (Prostigmata: Tetranychidae and the predatory mite Phytoseius horridus (Mesostigmata: Phytoseiidae (Solanum melongena have been found on eggplant. The noneconomically important species of Brevipalpus californicus(Banks Prostigmata: Tenuipalpidae,Eupodes sp. (Acarina: Eupodidae and predator Cunaxa sp. (Prostigmata: Cunaxidae have been reported on guava (Psidium guajava L.. Also, the non-economically important species Brevipalpus californicus Prostigmata: Tenuipalpidae, Lepidoglyphus destructor (Astigmata: Glycyphagidae and a predator Amblyseius obtusus, species group Amblyseius near lentiginosus (Mesostigmata: Phytoseiidae, have been recorded on cycad (Cycas micronesica.

  4. 攀枝花苏铁自然保护区夏季PM2.5中二次有机物的研究%Secondary organic tracers in summer PM2.5 aerosols from Sichuan Panzhihua Cycad National Nature Reserve

    Institute of Scientific and Technical Information of China (English)

    赖玮; 杨永琼; 李黎; 代东决; 余志祥; 莫恒勤; 蒲金国; 邓仕槐

    2014-01-01

    采用混合溶剂提取、N,O-双(三甲硅醚)-三氟乙酰胺(BSTFA)衍生化预处理和 GC/MS 分析技术,对四川攀枝花苏铁国家自然保护区PM2.5中的大气二次有机气溶胶进行了定量检测,探讨了研究区域内气溶胶中异戊二烯、α-/β-蒎烯光氧化产物、β-石竹酸及小分子羧酸和的浓度水平与变化规律,并讨论了有机物占有机碳(OC)的比值。结果表明,24 h PM2.5中,异戊二烯光氧化产物、α-/β-蒎烯光氧化产物和β-石竹酸的平均浓度分别为51.2、16.1和1.7 ng/m3;苹果酸和2-羟基戊二酸的平均浓度分别为12.4 ng/m3和4.9 ng/m3。OC和元素碳(EC)的平均浓度分别为20.3μg/m3和5.9μg/m3。异戊二烯氧化产物、α-/β-蒎烯氧化产物及β-石竹烯氧化产物对OC的贡献率分别为1.63%、0.34%和0.36%。%PM2.5 aerosol samples, collected during the summer of 2011 in Sichuan Panzhihua Cycad National Nature Reserve, were extracted with mixed solution, derivatized with N,O-bis-(trimethylsilyl) trifluoroacetamide (BSTFA) and analyzed by gas chromatography/mass spectrometry (GC/MS). The objectives of this study were to examine the time series of photooxidation products of isoprene, α-/β-pinene and β-caryophyllene and of some small molecular carboxylic acids, to determine their concentrations and estimate their contributions to aerosol organic carbon (OC). The results showed that average concentrations of total isoprene and α-/β-pinene oxidation products and β-caryophyllinic acid in 24 h PM2.5 aerosol samples were 51.2, 16.1 and 1.7 ng/m3, respectively. Average levels of malic acid and 2-hydroxyglutaric acid were 12.4 ng/m3 and 4.9 ng/m3, and the mean concentrations of OC and elemental carbon (EC) were 20.3 μg/m3 and 5.9 μg/m3, respectively. Contributions of isoprene, α-/β-pinene and β-caryophyllene oxidation products to OC were 1.63%, 0.34% and 0.36% during sampling campaign, respectively.

  5. The DOF transcription factor Dof5.1 influences leaf axial patterning by promoting Revoluta transcription in Arabidopsis

    KAUST Repository

    Kim, Hyungsae

    2010-10-05

    Dof proteins are transcription factors that have a conserved single zinc finger DNA-binding domain. In this study, we isolated an activation tagging mutant Dof5.1-D exhibiting an upward-curling leaf phenotype due to enhanced expression of the REV gene that is required for establishing adaxialabaxial polarity. Dof5.1-D plants also had reduced transcript levels for IAA6 and IAA19 genes, indicating an altered auxin biosynthesis in Dof5.1-D. An electrophoretic mobility shift assay using the Dof5.1 DNA-binding motif and the REV promoter region indicated that the DNA-binding domain of Dof5.1 binds to a TAAAGT motif located in the 5′-distal promoter region of the REV promoter. Further, transient and chromatin immunoprecipitation assays verified binding activity of the Dof5.1 DNA-binding motif with the REV promoter. Consistent with binding assays, constitutive over-expression of the Dof5.1 DNA-binding domain in wild-type plants caused a downward-curling phenotype, whereas crossing Dof5.1-D to a rev mutant reverted the upward-curling phenotype of the Dof5.1-D mutant leaf to the wild-type. These results suggest that the Dof5.1 protein directly binds to the REV promoter and thereby regulates adaxialabaxial polarity. © 2010 Blackwell Publishing Ltd.

  6. Genome sizes for all genera of Cycadales.

    Science.gov (United States)

    Zonneveld, B J M

    2012-01-01

    Nuclear DNA content (2C) is reported for all genera of the Cycadales, using flow cytometry with propidium iodide. Nuclear DNA content ranges from 24 to 64 pg in cycads. This implies that the largest genome contains roughly 40 × 10(9) more base pairs than the smallest genome. The narrow range in nuclear DNA content within a genus is remarkable for such an old group. Furthermore, 42 of the 58 plants measured, covering five genera, have 18 chromosomes. They vary from 36.1 to 64.7 pg, covering the whole range of genome sizes (excluding the genome of Cycas). Hence, their does not seem to be a correlation between genome size and the number of chromosomes.

  7. Analysis of the soluble cell wall proteome of gymnosperms.

    Science.gov (United States)

    Uzal, Esther Novo; Gómez-Ros, Laura V; Hernández, Jose A; Pedreño, María A; Cuello, Juan; Ros Barceló, Alfonso

    2009-05-15

    We analyzed the cell wall proteome of lignifying suspension cell cultures (SCCs) from four gymnosperms that differ in evolution degree. This analysis showed the presence of "peptide sequence tags" (PSTs) corresponding to glucan endo-1,3-beta-D-glucosidase, xyloglucan-endotrans-glucosylase/hydrolase, chitinases, thaumatin-like proteins and proteins involved in lignin/lignan biosynthesis, such as dirigent-like proteins and peroxidases. Surprisingly, and given the abundance of peroxidases in the cell wall proteome of these gymnosperms, PSTs corresponding to peroxidases were only detected in tryptic fragments of the cell wall proteome of Cycas revoluta. The current lack of knowledge regarding C. revoluta peroxidases led us to purify, characterize and partially sequence the peroxidases responsible for lignin biosynthesis in this species. This yielded three peroxidase-enriched fractions: CrPrx 1, CrPrx 2 and CrPrx 3. Analyses of tryptic peptides of CrPrx 2 (32kDa) and CrPrx 3 (26kDa) suggest that CrPrx 3 arises from CrPrx 2 by protein truncation, and that CrPrx 3 apparently constitutes a post-translational modification of CrPrx 2. That CrPrx 2 and CrPrx 3 are apparently the same enzyme was also deduced from the similarity between the k(cat) shown by both peroxidases for the three monolignols. These results emphasize the analogies between the cell wall proteome of gymnosperms and angiosperms, the complexity of the peroxidase proteome, and the difficulties involved in establishing fine structure-function relationships.

  8. Analysis of the sugar-binding specificity of mannose-binding-type Jacalin-related lectins by frontal affinity chromatography--an approach to functional classification.

    Science.gov (United States)

    Nakamura-Tsuruta, Sachiko; Uchiyama, Noboru; Peumans, Willy J; Van Damme, Els J M; Totani, Kiichiro; Ito, Yukishige; Hirabayashi, Jun

    2008-03-01

    The Jacalin-related lectin (JRL) family comprises galactose-binding-type (gJRLs) and mannose-binding-type (mJRLs) lectins. Although the documented occurrence of gJRLs is confined to the family Moraceae, mJRLs are widespread in the plant kingdom. A detailed comparison of sugar-binding specificity was made by frontal affinity chromatography to corroborate the structure-function relationships of the extended mJRL subfamily. Eight mJRLs covering a broad taxonomic range were used: Artocarpin from Artocarpus integrifolia (jackfruit, Moraceae), BanLec from Musa acuminata (banana, Musaceae), Calsepa from Calystegia sepium (hedge bindweed, Convolvulaceae), CCA from Castanea crenata (Japanese chestnut, Fagaceae), Conarva from Convolvulus arvensis (bindweed, Convolvulaceae), CRLL from Cycas revoluta (King Sago palm tree, Cycadaceae), Heltuba from Helianthus tuberosus (Jerusalem artichoke, Asteraceae) and MornigaM from Morus nigra (black mulberry, Moraceae). The result using 103 pyridylaminated glycans clearly divided the mJRLs into two major groups, each of which was further divided into two subgroups based on the preference for high-mannose-type N-glycans. This criterion also applied to the binding preference for complex-type N-glycans. Notably, the result of cluster analysis of the amino acid sequences clearly corresponded to the above specificity classification. Thus, marked correlation between the sugar-binding specificity of mJRLs and their phylogeny should shed light on the functional significance of JRLs.

  9. 苏铁与蓝细菌的共生%CYANOBACTERIA-CYCADS SYMBIOSES

    Institute of Scientific and Technical Information of China (English)

    陈彬; 郑斯平; 郑伟文

    2007-01-01

    蓝细菌能与不同进化阶段的植物代表种共生,苏铁是能与蓝细菌共生的唯一的裸子植物.本文从蓝细菌与苏铁超显微结构、共生蓝细菌的多态性、蓝细菌对苏铁珊瑚状根的侵染和研究展望等几个方面阐述了苏铁与蓝细菌的共生关系,认为从分子水平上揭示蓝细菌与苏铁形成共生固氮体系的系统性和共生双方的遗传多样性,不仅具有重要的意义,而且也具有广阔的应用前景.

  10. Cycad Forest Artificially%攀枝花苏铁人工还林

    Institute of Scientific and Technical Information of China (English)

    杨永琼; 余志祥

    2004-01-01

    位于攀枝花市西区、仁和区的攀枝花苏铁林,是现今我国及至亚洲天然分布面积最大、株数最多、纬度最北的原始苏铁林。因其珍贵、稀有、古老等特点,与恐龙化石、大熊猫合称“巴蜀三宝”,引起了专家学者的极大兴趣。攀枝花是我国六十年代三线建设时开始建设的一座新兴的钢铁城市,在建设之初,由于没有足够的的认识,

  11. General Outline of study on Cycads%苏铁植物研究概况

    Institute of Scientific and Technical Information of China (English)

    周燕; 张晓; 彭树林; 丁立生

    2001-01-01

    苏铁植物分11属共200余种,其中许多种的化学成分和药理作用已陆续有报道.本文综述了历年来国内外对苏铁植物的化学成分和毒理、药理方面的研究情况.

  12. Sphenophytes, pteridosperms and possible cycads from the Wuchiapingian (Lopingian, Permian) of Bletterbach (Dolomites, Northern Italy)

    NARCIS (Netherlands)

    Kustatscher, E.; Bauer, K.; Butzmann, R.; Fischer, T.C.; Meller, B.; van Konijnenburg-van Cittert, J.H.A.; Kerp, H.

    2014-01-01

    The Bletterbach flora is the most important late Permian (Lopingian) flora of the Southern Alps. The study of a new fossiliferous bed stratigraphically below the cephalopod bed yielded almost 500 plant fossils, 28 of which belong to rare Lopingian plant groups: horsetails, seed ferns and possible cy

  13. Scale insects and their natural enemies of Cycas revolute%苏铁蚧虫及其天敌

    Institute of Scientific and Technical Information of China (English)

    蔡子坚; 罗佳

    2004-01-01

    通过对我省10县市的调查、采集和鉴定,苏铁蚧虫计有15种,隶属4科、10属.发生最普遍、最严重的是咖啡盔蚧和酱褐圆蚧.天敌有寄生性天敌15种、捕食性天敌6种和寄生菌1种.

  14. Priorities for genetic resource collection and preservation of wild gymnosperms in Yunnan: an analysis based on the "3E" principle%用3E原则评价云南野生裸子植物遗传资源收集保存的优先性

    Institute of Scientific and Technical Information of China (English)

    黄天才; 龙春林

    2011-01-01

    为了探讨局部地区遗传资源优先性评价的方法和管理问题,我们采用"3E"原则对云南裸子植物进行了评价."3E"分别指珍稀濒危的(Endangered)、特有的(Endemic)和具有经济价值的(Economic)三个方面.我们首先介绍了"3E"原则的由来、内涵和价值,并应用"3E"原则,以种(变种)为分析单元,对分布于云南的10科29属107种(变种)野生裸子植物遗传资源的状况进行了分析,确定了需要优先保护的遗传资源类群.结果表明,云南省野生裸子植物资源兼有受威胁严重、特有率高、经济价值高等多种特征,如南方红豆杉(Taxus chinensis var.mairei)、灰干苏铁(Cycas hongheensis)、油麦吊云杉(Picea brachytyla var.complanata)等58种不仅受威胁严重,而且具有重要的经济价值和潜在的开发利用价值.具有"3E"特性的裸子植物遗传资源有72种,其中贡山三尖杉(Cephalotaxus lanceolata)、苏铁(Cycas revoluta)、大理罗汉松(Podocarpus forrestii)、德保苏铁(C.debaoensis)、德钦柏(Juniperus baimashanensis)、巧家五针松(Pinus squamata)、灰干苏铁、万钧柏(J.chengii)、毛枝五针松(P.wangii)等9种亟待进行抢救性保存,中甸冷杉(Abies ferreana)、绿春苏铁(C.tangingii)、麦吊杉(Picea brachytyla)、怒江冷杉(A.nukiangensis)、河内苏铁(C.tonkinensis)等40种需要优先收集和保存.保存的方式包括原地保存、异地保存、设施保存和栽培利用等综合措施.将"3E"原则应用于云南裸子植物遗传资源的管理,具有科学合理性和可操作性,对遗传资源的保护和可持续利用具有一定的参考价值.%The “3E" principle has been used to determine priorities for preservation of genetic resources in conservation and research projects. The three “E"s refer to Endangered, Endemic, and Economic. Here, we applied this principle to explore wild gymnosperm genetic resources (or germplasm resources) at the species (varieties) level occurring in

  15. The mechanism of pollination drop withdrawal in Ginkgo biloba L.

    Directory of Open Access Journals (Sweden)

    Jin Biao

    2012-05-01

    Full Text Available Abstract Background The pollination drop (PD is a characteristic feature of many wind-pollinated gymnosperms. Although accumulating evidence shows that the PD plays a critical role in the pollination process, the mechanism of PD withdrawal is still unclear. Here, we carefully observed the PD withdrawal process and investigated the underlying mechanism of PD withdrawal, which will aid the understanding of wind-pollination efficiency in gymnosperms. Results In Ginkgo biloba, PDs were secreted on the micropyle during the pollination period and persisted for about 240 h when not pollinated under laboratory conditions. The withdrawal of an isolated PD required only 1 h for evaporation, much less than a PD on the living ovule, which required 100 h. When pollinated with viable pollen, PDs withdrew rapidly within 4 h. In contrast, nonviable pollen and acetone-treated pollen did not cause PD withdrawal. Although 100% relative humidity significantly inhibited PD withdrawal, pollinated PDs still could withdraw completely within 48 h. Pollen grains of Cycas revoluta, which are similar to those of G. biloba, could induce PD withdrawal more rapidly than those of two distantly related gymnosperms (Pinus thunbergii and Abies firma or two angiosperms (Paeonia suffruticosa and Orychophragmus violaceus. Furthermore, pollen of G. biloba and C. revoluta submerged immediately when encountering the PD, then sank to the bottom and entered the micropyle. The saccate pollen of P. thunbergii and A. firma submerged into the PD, but remained floating at the top and finally accumulated on the micropyle after PD withdrawal. In contrast, pollen of the angiosperms P. suffruticosa, Salix babylonica, and O. violaceus did not submerge, instead remaining clustered at the edge without entering the PD. Conclusions We conclude that PD withdrawal is primarily determined by the dynamic balance between evaporation and ovule secretion, of which pollen is a critical stimulator

  16. Taxonomy Icon Data: [Taxonomy Icon

    Lifescience Database Archive (English)

    Full Text Available mphii_NS.png http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Cycas+rumphii&t=L http://biosciencedbc.jp/taxonomy..._icon/icon.cgi?i=Cycas+rumphii&t=NL http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Cycas+rumphii&t=S http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Cycas+rumphii&t=NS ...

  17. DNA barcoding in the cycadales: testing the potential of proposed barcoding markers for species identification of cycads.

    Directory of Open Access Journals (Sweden)

    Chodon Sass

    Full Text Available Barcodes are short segments of DNA that can be used to uniquely identify an unknown specimen to species, particularly when diagnostic morphological features are absent. These sequences could offer a new forensic tool in plant and animal conservation-especially for endangered species such as members of the Cycadales. Ideally, barcodes could be used to positively identify illegally obtained material even in cases where diagnostic features have been purposefully removed or to release confiscated organisms into the proper breeding population. In order to be useful, a DNA barcode sequence must not only easily PCR amplify with universal or near-universal reaction conditions and primers, but also contain enough variation to generate unique identifiers at either the species or population levels. Chloroplast regions suggested by the Plant Working Group of the Consortium for the Barcode of Life (CBoL, and two alternatives, the chloroplast psbA-trnH intergenic spacer and the nuclear ribosomal internal transcribed spacer (nrITS, were tested for their utility in generating unique identifiers for members of the Cycadales. Ease of amplification and sequence generation with universal primers and reaction conditions was determined for each of the seven proposed markers. While none of the proposed markers provided unique identifiers for all species tested, nrITS showed the most promise in terms of variability, although sequencing difficulties remain a drawback. We suggest a workflow for DNA barcoding, including database generation and management, which will ultimately be necessary if we are to succeed in establishing a universal DNA barcode for plants.

  18. 园林艺术之植物珍品——苏铁%Garden art treasures of plants - cycads

    Institute of Scientific and Technical Information of China (English)

    周卫

    2011-01-01

    苏铁树形古雅,主干粗壮,坚硬如铁;羽叶洁滑光亮,四季常青,为珍贵观赏树种.南方多植于庭前阶旁及草坪内;北方宜作大型盆栽,布置庭院屋廊及厅室,殊为美观.

  19. DNA barcoding in the cycadales: testing the potential of proposed barcoding markers for species identification of cycads.

    Science.gov (United States)

    Sass, Chodon; Little, Damon P; Stevenson, Dennis Wm; Specht, Chelsea D

    2007-11-07

    Barcodes are short segments of DNA that can be used to uniquely identify an unknown specimen to species, particularly when diagnostic morphological features are absent. These sequences could offer a new forensic tool in plant and animal conservation-especially for endangered species such as members of the Cycadales. Ideally, barcodes could be used to positively identify illegally obtained material even in cases where diagnostic features have been purposefully removed or to release confiscated organisms into the proper breeding population. In order to be useful, a DNA barcode sequence must not only easily PCR amplify with universal or near-universal reaction conditions and primers, but also contain enough variation to generate unique identifiers at either the species or population levels. Chloroplast regions suggested by the Plant Working Group of the Consortium for the Barcode of Life (CBoL), and two alternatives, the chloroplast psbA-trnH intergenic spacer and the nuclear ribosomal internal transcribed spacer (nrITS), were tested for their utility in generating unique identifiers for members of the Cycadales. Ease of amplification and sequence generation with universal primers and reaction conditions was determined for each of the seven proposed markers. While none of the proposed markers provided unique identifiers for all species tested, nrITS showed the most promise in terms of variability, although sequencing difficulties remain a drawback. We suggest a workflow for DNA barcoding, including database generation and management, which will ultimately be necessary if we are to succeed in establishing a universal DNA barcode for plants.

  20. 苏铁植物无性繁殖技术研究%Study on Vegetative Propagation of Cycad Plants

    Institute of Scientific and Technical Information of China (English)

    伍群玉; 黄中强; 马书云; 顾祖扬; 邓国永

    2007-01-01

    采用分蘖繁殖和切干繁殖两种方法,对苏铁、台湾苏铁、红河苏铁、鳞秕苏铁、攀枝花苏铁、叉叶苏铁、石山苏铁、云南苏铁等2科8种苏铁进行无性繁殖试验,通过对比分析,找出了苏铁植物无性繁殖的有效方法,并总结出相应的繁殖技术要点.

  1. Non-functional plastid ndh gene fragments are present in the nuclear genome of Norway spruce (Picea abies L. Karsch): insights from in silico analysis of nuclear and organellar genomes.

    Science.gov (United States)

    Ranade, Sonali Sachin; García-Gil, María Rosario; Rosselló, Josep A

    2016-04-01

    Many genes have been lost from the prokaryote plastidial genome during the early events of endosymbiosis in eukaryotes. Some of them were definitively lost, but others were relocated and functionally integrated to the host nuclear genomes through serial events of gene transfer during plant evolution. In gymnosperms, plastid genome sequencing has revealed the loss of ndh genes from several species of Gnetales and Pinaceae, including Norway spruce (Picea abies). This study aims to trace the ndh genes in the nuclear and organellar Norway spruce genomes. The plastid genomes of higher plants contain 11 ndh genes which are homologues of mitochondrial genes encoding subunits of the proton-pumping NADH-dehydrogenase (nicotinamide adenine dinucleotide dehydrogenase) or complex I (electron transport chain). Ndh genes encode 11 NDH polypeptides forming the Ndh complex (analogous to complex I) which seems to be primarily involved in chloro-respiration processes. We considered ndh genes from the plastidial genome of four gymnosperms (Cryptomeria japonica, Cycas revoluta, Ginkgo biloba, Podocarpus totara) and a single angiosperm species (Arabidopsis thaliana) to trace putative homologs in the nuclear and organellar Norway spruce genomes using tBLASTn to assess the evolutionary fate of ndh genes in Norway spruce and to address their genomic location(s), structure, integrity and functionality. The results obtained from tBLASTn were subsequently analyzed by performing homology search for finding ndh specific conserved domains using conserved domain search. We report the presence of non-functional plastid ndh gene fragments, excepting ndhE and ndhG genes, in the nuclear genome of Norway spruce. Regulatory transcriptional elements like promoters, TATA boxes and enhancers were detected in the upstream regions of some ndh fragments. We also found transposable elements in the flanking regions of few ndh fragments suggesting nuclear rearrangements in those regions. These evidences

  2. Phylogeny of the cycads based on multiple single-copy nuclear genes: congruence of concatenated parsimony, likelihood and species tree inference methods

    National Research Council Canada - National Science Library

    Salas-Leiva, Dayana E; Meerow, Alan W; Calonje, Michael; Griffith, M Patrick; Francisco-Ortega, Javier; Nakamura, Kyoko; Stevenson, Dennis W; Lewis, Carl E; Namoff, Sandra

    2013-01-01

    .... The specific aim is to evaluate several gene tree-species tree reconciliation approaches for developing an accurate phylogeny of the order, to contrast them with concatenated parsimony analysis...

  3. 攀枝花市苏铁植物保护与利用初探%Prevention & Uitalization of Cycad in Panzhihua

    Institute of Scientific and Technical Information of China (English)

    黄中强; 黄秀芳; 朱永玲; 杨永琼

    2003-01-01

    攀枝花市有亚洲最大,株数最多,分布最集中的苏铁原生林,被列为国家级自然保护区,城区建有苏铁植物园.本文在总结攀枝花市二十多年来对苏铁保护工作的基础上,对苏铁植物就地、迁地保护与开发利用提出了研究对策及意见.

  4. Metabotropic glutamate receptor 1 mediates the electrophysiological and toxic actions of the cycad derivative beta-N-Methylamino-L-alanine on substantia nigra pars compacta DAergic neurons.

    Science.gov (United States)

    Cucchiaroni, Maria Letizia; Viscomi, Maria Teresa; Bernardi, Giorgio; Molinari, Marco; Guatteo, Ezia; Mercuri, Nicola B

    2010-04-14

    Amyotrophic lateral sclerosis-Parkinson dementia complex (ALS-PDC) is a neurodegenerative disease with ALS, parkinsonism, and Alzheimer's symptoms that is prevalent in the Guam population. beta-N-Methylamino alanine (BMAA) has been proposed as the toxic agent damaging several neuronal types in ALS-PDC, including substantia nigra pars compacta dopaminergic (SNpc DAergic) neurons. BMAA is a mixed glutamate receptor agonist, but the specific pathways activated in DAergic neurons are not yet known. We combined electrophysiology, microfluorometry, and confocal microscopy analysis to monitor membrane potential/current, cytosolic calcium concentration ([Ca(2+)](i)) changes, cytochrome-c (cyt-c) immunoreactivity, and reactive oxygen species (ROS) production induced by BMAA. Rapid toxin applications caused reversible membrane depolarization/inward current and increase of firing rate and [Ca(2+)](i) in DAergic neurons. The inward current (I(BMAA)) was mainly mediated by activation of metabotropic glutamate receptor 1 (mGluR1), coupled to transient receptor potential (TRP) channels, and to a lesser extent, AMPA receptors. Indeed, mGluR1 (CPCCOEt) and TRP channels (SKF 96365; Ruthenium Red) antagonists reduced I(BMAA), and a small component of I(BMAA) was reduced by the AMPA receptor antagonist CNQX. Calcium accumulation was mediated by mGluR1 but not by AMPA receptors. Application of a low concentration of NMDA potentiated the BMAA-mediated calcium increase. Prolonged exposure to BMAA caused significant modifications of membrane properties, calcium overload, cell shrinkage, massive cyt-c release into the cytosol and ROS production. In SNpc GABAergic neurons, BMAA activated only AMPA receptors. Our study identifies the mGluR1-activated mechanism induced by BMAA that may cause the neuronal degeneration and parkinsonian symptoms seen in ALS-PDC. Moreover, environmental exposure to BMAA might possibly also contribute to idiopathic PD.

  5. Preventing Chilades pandava from damaging cycad during leaf emergence period%苏铁出叶期严防曲纹紫灰蝶危害

    Institute of Scientific and Technical Information of China (English)

    丘年华; 洪春莉

    2006-01-01

    苏铁是优良的观叶植物。但在苏铁生长的春、秋出叶期必须严防曲纹紫灰蝶危害其幼嫩的羽状叶片、雌雄蕊花序,才能使其绿叶婆娑、青翠欲滴。保持良好的观赏价值与经济价值。

  6. CTAB法提取苏铁基因组DNA的条件优化%Research of optimizing CTAB method in DNA extraction of cycad using orthogonal experiment design

    Institute of Scientific and Technical Information of China (English)

    李东亮; 金红; 张勇; 翟伟博; 景建洲

    2007-01-01

    采用单因素梯度试验结合正交实验的方法(CTAB法),优化了苏铁类植物全基因组DNA提取工艺.研究表明:材料量对提取DNA的浓度、提取率和纯度的影响最为明显,但还没有达到显著水平;最佳工艺参数为:20 mg苏铁羽片,65℃水浴处理30 min,抽提后,加入800 μL无水乙醇和5μL饱和NaCl溶液,6 000 r/min离心4 min沉淀DNA;溶解再沉淀后的DNA,质量浓度可达0.241 3 g/L,提取率可达0.483%,|OD260/OD280-1.8|<0.01,可以满足RAPD-PCR分子标记技术应用.

  7. 银杏和苏铁类植物的生殖特征比较%Review of Reproductive Characters in Ginkgo and Cycads

    Institute of Scientific and Technical Information of China (English)

    安丽华; 王宝娟; 吉成均

    2007-01-01

    银杏和苏铁类植物是现存种子植物中仅有的2个具多鞭毛游动精子的类群.自1896年Hirase和Ikeno分别发现银杏和苏铁类植物的游动精子以来,研究人员对它们的生活史、胚胎发育、系统演化等已进行了大量研究.本文综述了近年来银杏和苏铁类植物在生殖生物学方面的研究进展,比较了它们生殖特征的异同,并对它们间的亲缘关系进行了初步探讨.通过对一些演化上有重大意义的特征的比较,显示在雄配子体发育及种子发育方面苏铁类植物较银杏保留了更为原始的特征,而在雌配子体发育方面则较银杏更为特化;银杏和苏铁类植物均具有许多特有的结构特征,表明两者在进化过程中是平行发展的,在种系发生上不相关.

  8. The Brief Report on First Discovery of Vessel in Cycads%首次在苏铁类植物中发现导管

    Institute of Scientific and Technical Information of China (English)

    黄玉源; 张宏达

    1999-01-01

    本研究通过对鳞秕泽米铁(Zamia furfuracea)的羽片进行离析观察和电镜观察,发现其木质部中具有导管,导管类型有6种,其中环纹、螺纹导管为单穿孔板,梯纹、孔纹、网纹等导管为复穿孔板.这是首次在苏铁类植物中发现导管,对于植物学多门学科领域具有极为重要的意义.

  9. Optimization of PCR Conditions for Symbiosis of Cyanobacteria in Cycads%苏铁共生蓝细菌PCR条件的优化

    Institute of Scientific and Technical Information of China (English)

    包晓东; 宋铁英; 郑伟文

    2002-01-01

    在研究苏铁共生蓝细菌的种群多态性过程中,为了直接以极少量的新鲜蓝细菌为PCR反应模板,对5种抗抑制剂进行了一系列优化组合方案的试验,并对比了3种循环参数,发现在25μL标准反应液基础上加有3.75μL 10% BSA和2μL 10% DMSO,退火温度为56℃时效果最佳.

  10. La flora cretácica de Cuenca Neuquina, su significadopaleoambiental y paleoclimático The Cretaceous flora of the Neuquén Basin,its paleoenvironmental and paleoclimatic significance

    Directory of Open Access Journals (Sweden)

    Eduardo G. Ottone

    2009-10-01

    Full Text Available Se sumariza el significadopaleoambiental y paleoclimático de la flora cretácica de cuenca Neuquina. Lasasociaciones palinológicas del Berriasiano-Barremiano están dominadas por Araucariaceaey Cheirolepidiaceae, con Podocarpaceae, helechos, licópsidas y briofitassubordinadas que habrían progresado en un clima templado y húmedo. Losdinoflagelados del Tithoniano- Barremiano temprano mayormente poseen afinidadesmediterráneas. Los niveles evaporíticos del Barremiano superior representan lafinalización del ciclo marino de depositación relacionado con el océanoPacífico en la cuenca. En el Aptiano aparece el primer grano de polen deangiosperma. Las asociaciones palinológicas continentales delAptiano-Cenomaniano se caracterizan por presentar elementos del Gondwanaseptentrional tales como Afropollis y los granos de polen elaterados.Tempskyaceae y Ginkgoales están también presentes en el Cretácico Tempranotardío. Los estratos continentales del Turoniano- Campaniano inferior incluyenprincipalmente madera petrificada y carofitas. Los estratos del Campanianosuperior- Maastrichtiano preservan una rica asociación palinológica de origencontinental compuesta por Nothofagaceae, Podocarpaceae, Cheirolepidiaceae,Araucariaceae, Salviniales y angiospermas, aunque también hay dinoflageladosque reflejan el comienzo de una transgresión marina relacionada con el océanoAtlántico. La presencia y abundancia local de cycas y palmeras sugiere el desarrollode un clima templado cálido y relativamente húmedo hacia fines del Cretácico.The paleoenvironmental and paleoclimaticsignificance of Cretaceous flora in the Neuquén Basin is summarized. Berriasian-Barremianterrestrial palynological assemblages are dominated by Araucariaceae andCheirolepidiaceae, with subordinated podopcarps, ferns, lycopsids andbryophytes that progressed in a mild and humid climate. Tithonian-Barremiandinoflagellates mostly possess Mediterranean affinities. Upper

  11. The primary locus of motor neuron death in an ALS–PDC mouse model

    OpenAIRE

    2009-01-01

    A mouse model of amyotrophic lateral sclerosis–parkinsonism–dementia complex based on the consumption of cycad seed flour was used to determine whether the observed pathology of motor neuron loss begins in the distal axons or the spinal cord. Assessments of neuromuscular junction integrity and motor neurons were performed at multiple time points. Mice fed cycad pellets performed worse on the wire hang than controls. Microglial activation in cycad-fed mice was observed with motor neuron degene...

  12. Publishing trends for the Cycadales, the most threatened plant group

    Directory of Open Access Journals (Sweden)

    April N. Cascasan

    2016-03-01

    Full Text Available Trends in published cycad research within various fields of study were determined using proceedings from international conferences on cycad biology and Google Scholar to access the primary literature.  Both search methods indicated that phylogeny, systematics and ecology are strongly represented in recent cycad literature, while there is a need for more research in horticulture and pathology, reviews and clarification of correspondence between current and discontinued species designations.  

  13. ChrR positively regulates transcription of the Rhodobacter sphaeroides cytochrome c2 gene.

    Science.gov (United States)

    Schilke, B A; Donohue, T J

    1995-04-01

    Transcription of the Rhodobacter sphaeroides cytochrome c2 gene (cycA) is negatively regulated by both the presence of oxygen and intermediates in tetrapyrrole biosynthesis. A mutation responsible for uncoupling cycA transcription from tetrapyrrole availability was localized to a gene (chrR) that encodes a 357-amino-acid protein. Analysis of a defined chrR null mutation indicated that this protein positively regulated cycA transcription. From this and other results, it appeared that the positive action of ChrR on cycA transcription is blocked by altering the availability of either heme or some intermediate in tetrapyrrole biosynthesis. A single missense mutation which substitutes an Arg for a Cys at residue 182 of ChrR (C182R) was shown to be necessary and sufficient for the increased cycA transcription seen in the mutant strain Chr4. Thus, it appears that this C182R substitution generated an altered-function form of ChrR. In addition, by analyzing cycA transcription in delta ChrR strains, we showed that ChrR was not required for increased cycA transcription under anaerobic conditions. Instead, our results indicated that ChrR and the response regulator PrrA (J. M. Eraso and S. Kaplan, J. Bacteriol. 176:32-43, 1994) functioned independently at the upstream cycA promoter that is activated under anaerobic conditions.

  14. Recent synchronous radiation of a living fossil.

    Science.gov (United States)

    Nagalingum, N S; Marshall, C R; Quental, T B; Rai, H S; Little, D P; Mathews, S

    2011-11-11

    Modern survivors of previously more diverse lineages are regarded as living fossils, particularly when characterized by morphological stasis. Cycads are often cited as a classic example, reaching their greatest diversity during the Jurassic-Cretaceous (199.6 to 65.5 million years ago) then dwindling to their present diversity of ~300 species as flowering plants rose to dominance. Using fossil-calibrated molecular phylogenies, we show that cycads underwent a near synchronous global rediversification beginning in the late Miocene, followed by a slowdown toward the Recent. Although the cycad lineage is ancient, our timetrees indicate that living cycad species are not much older than ~12 million years. These data reject the hypothesized role of dinosaurs in generating extant diversity and the designation of today's cycad species as living fossils.

  15. 苏铁种子不同处理方式播种育苗试验%Sowing trial for seedlings breeding by using different seed-treating methods of sago cycad

    Institute of Scientific and Technical Information of China (English)

    邓元德; 张秀华

    2016-01-01

    采用低温和化学药剂对苏铁种子进行处理,结果表明:低温沙藏处理和98%浓硫酸处理均能使苏铁种子发芽提早和发芽率提高.其中:低温沙藏的苏铁种子最早发芽,比冷水浸种(对照)提前104 d,且发芽率提高58.89个百分点;98%浓硫酸处理的苏铁种子发芽率最高,达71.11%,比冷水浸种的发芽率提高68.33个百分点,提前99 d发芽.

  16. The Study on Multicopy of ITS Sequences of Nostoc in Cycads Revolute%苏铁珊瑚根共生念珠藻ITS序列多拷贝研究

    Institute of Scientific and Technical Information of China (English)

    粟绒; 焦淑静; 黄现恩; 张青; 史全良

    2014-01-01

    目的:研究苏铁珊瑚根共生念珠藻16SrDNA-23SrDNA基因间隔序列(ITS)拷贝数.方法:提取苏铁珊瑚根共生念珠藻全DNA,PCR扩增其16SrDNA-23SrDNA基因间隔序列(ITS)克隆并测序;采用Cluster X 1.83对所得序列进行比对,用DNAman软件对比对结果进行人工校正;采用割胶回收电泳检测、菌液PCR及混合模板PCR扩增三种方法验证ITS-L2.结果:ITS-S(420 bp)不合任何氨基酸编码序列,ITS-L1(676 bp)包含一个异亮氨酸和一个丙氨酸编码序列;ITS-L1和ITS-L2在琼脂糖凝胶电泳检测时长度分别为676 bp和1000 bp,而谱带经克隆测序后结果表明ITS-L1和ITS-L2碱基序列和长度几乎相同,仅有两个碱基发生变异.结论:ITS-L2为假阳性,可能是由ITS-S和ITS-L1形成的异源双链;苏铁珊瑚根共生念珠藻含有两种类型的ITS拷贝,一种是含有tRNAIle和tRNAAla编码序列的ITS,另一种是不合tRNAIle和tRNAAla编码序列的ITS.

  17. 几种引物对苏铁共生蓝细菌的DNA多态性分析%DNA diversity analysis on the Cyanobacteria freshly isolate d from Cycads based on PCR with different primers

    Institute of Scientific and Technical Information of China (English)

    宋铁英; 陈坚; 包晓东; 郑伟文; 郑芳勤

    2001-01-01

    选用2种STRR引物和4种Hip引物对15个苏铁品种的25个苏铁共生蓝藻样品进行PCR指纹图谱分析,通过对这6种引物分析结果的比较,表明STRR引物68051能较好揭示苏铁共生蓝藻的DNA 多态性,试验结果也表明苏铁共生蓝藻和苏铁的共生并非专一.

  18. A Discussion of the Relations Between Cycad Plants By Clustering Analysis%用聚类分析法探讨苏铁类植物之间的关系

    Institute of Scientific and Technical Information of China (English)

    郑芳勤

    2001-01-01

    用聚类分析法探讨苏铁类植物相互之间的亲缘关系,得到的结果和目前不少学者的分类系统有的相近、有的不一样,有一定的参考价值.关键是用于聚类的形态特征的项目不能太少,形态特征的性状界定一定要划分好.

  19. 攀枝花苏铁种植园土壤微生物数量及土壤酶活性分析%Analysis on number of microbes and enzymes activities of soil from Cycad plantation in Panzhihua

    Institute of Scientific and Technical Information of China (English)

    熊亚; 李敏杰

    2015-01-01

    以攀枝花苏铁种植园土壤及非种植园土壤(攀枝花公园土壤)为研究对象,分析其理化性状、土壤微生物数量与土壤酶活性及其相关性.结果表明,苏铁种植园土壤pH为6.52,水分含量为14.28%;尾矿坝土壤中各类菌群数量为细菌>放线菌>真菌;土壤酶活性大小为转化酶>磷酸酶>过氧化氢酶>脲酶,分别为23.131 mg/g·24h、 1.325 mg/100g· 2h、0.57 mL/g·20min、0.025 mg/g·24h;土壤微生物数量、土壤酶活性、土壤理化性状之间均存在相关性,土壤细菌、放线菌及真菌数量随着土壤含水量、脲酶和磷酸酶活性的增加而增加;随着转化酶及过氧化氢酶活性的增加而降低.

  20. The millennium cycads to blossom%千年铁树要开花——评A股上市对中华老字号公司的影响

    Institute of Scientific and Technical Information of China (English)

    叶朱演

    2008-01-01

    我国的中华老字号企业有着悠久的历史,在人们眼中,老字号往往就是质量和信誉的保证,具有独特的人文魅力。当然,它们的情况也差别很大,有的在市场经济大潮中焕发出勃勃生机,如同千年铁树再开花,有的则被“国际化”、“现代化”大潮所吞没、淘汰。但是,象“全聚德”、“东来顺”、“狗不理”等等当年一些人们耳熟能详的老字号经过市场的大浪淘沙,

  1. Study on the Resource of Endangered and Rare Plants in Wangmo Cycad Nature Reserve%贵州望谟苏铁自然保护区珍稀濒危植物资源研究

    Institute of Scientific and Technical Information of China (English)

    李慧; 韦堂灵

    2011-01-01

    根据标本采集和调查,保护区内有自然生长的珍稀濒危植物133种.其中:国家Ⅰ级保护植物4种,国家Ⅱ级保护植物18种,贵州省重点保护树种15种;附录Ⅰ兰科兜兰属4种,附录Ⅱ有仙人掌科仙人掌属1种及兰科32属90种.包括蕨类植物2科3属3种;裸子植物5科7属8种;被子植物18科58属122种.并对这些植物的分布特征、生态习性、利用价值、资源现状及保护措施进行了初步研究,这些珍稀物种,特别是一些经济利用价值较大的物种的生存状况,种群结构欠佳,急需加强对其现有个体和其生态环境的保护,辅以人为措施,促进其更新发展.

  2. 南宁青秀山风景区苏铁植物迁地保育探讨%The Ex-situ Conservation of Cycads in Mountain QingxiushanScenic Spotin Nanning

    Institute of Scientific and Technical Information of China (English)

    欧振飞

    2016-01-01

    指出了苏铁属珍稀濒危物种,是一个古老的植物类群,具有重要的科学研究和园林观赏价值,应积极保护.迁地保育是苏铁保护工作中一种重要而有效的方法.阐述了青秀山风景区苏铁植物迁地保育的情况,提出了深入开展苏铁植物保育和园林、科普、旅游综合应用的对策.

  3. 江西省某学校一起食用铁树果导致的中毒事件调查%Investigation on an event of poisoning caused by cycad fruit in a primary school of Jiangxi Province

    Institute of Scientific and Technical Information of China (English)

    李超; 刘俊; 陈卫国; 余平; 施国庆; 汪仕文; 彭海仁; 谢兰兰

    2015-01-01

    目的 查明江西省某小学一起聚集性呕吐事件原因.方法 病例定义:2013年9月13日至18日,在某小学学生中,出现呕吐、头痛、头晕、恶心、腹痛症状之一者.病例搜索采用各班级班主任分别询问的方式开展.原因探查采用回顾性队列研究,选择发病班级集中的三年级一班的所有学生为研究对象,回顾调查学生铁树果进食史及剂量.结果 共搜索到病例18例,全部为学生,病例分布在2个班级,发病班级罹患率为19% (18/97),病例集中在4h内发病,临床症状主要为呕吐(78%)、头晕(67%)、恶心(50%)、腹痛(44%).61% (11/18)的病例乳酸脱氢酶升高,检测值中位数为286 U/L(范围:263~369 U/L);22% (4/18)的病例出现凝血4项异常;17% (3/18)的病例出现白细胞升高,检测值中位数为12×109/L,范围:(11~ 13)×109/L.食用铁树果是发病的主要危险因素(RR=+∞,Fisher确切概率P=0.00008).结论 本次聚集性呕吐事件为食用铁树果导致的中毒事件.

  4. Biological Characteristic of Leaf Blight:A New Cycad Disease in Guizhou Province%贵州省铁树新病害叶枯病病原菌生物学特性研究

    Institute of Scientific and Technical Information of China (English)

    肖仲久; 李小霞; 许艾斌; 罗华燕; 潘合俊

    2012-01-01

    对贵州省铁树上发生的一种新病害-叶枯病病原菌进行了生物学特性研究,探讨不同温度、pH、光照、碳源及氮源等条件对该病原体菌丝生长、分生孢子萌发的影响,以期系统掌握该病原菌的生物学特性,为铁树叶枯病防治提供理论依据.结果表明:铁树叶枯病菌苗丝在10~35℃温度范围内均能生长,在15~35℃之间孢子均能萌发,菌丝生长和孢子萌发最适温度分别为30℃和25℃;在pH 2~12之间,病原菌菌丝(孢子)均能生长(萌发),其中pH为6时病原菌菌丝生长最好,pH为10时病原菌孢子萌发率最高;光照条件对菌丝的扩展和孢子萌发影响不明显;该病原菌对单糖、双糖、多糖等碳源以及有机氮和无机氮均能利用,其中以蔗糖作碳源时,菌丝生长和孢子萌发最佳,以硝酸钾作氮源时,菌丝生长最好,供试氮源对分生孢子的萌发均不佳.

  5. EARLY JURASSIC FOSSIL CYCADS FROM YIHE BASIN IN SOUTHERN JILIN PROVINCE: Paleoclimatic significance%吉林南部义和盆地早侏罗世几种苏铁类化石及其古气候意义

    Institute of Scientific and Technical Information of China (English)

    孙春林; 李涛; 孙跃武; 陈跃军; 李春田; 赵国伟

    2010-01-01

    报道了吉林南部早侏罗世义和植物群中的苏铁类化石3属7种,即ptrophyllum baotoum Zhang,Pterophyllum exhibens Li,Pterophllum cf.tietzei Schenk,Pterophyllum sp.,Nilssonia inouyei Yokyama,Nilssonia orientalis Heer,Cycadolepis corrugata Zeiler.同时,讨论了苏铁类化石的古气候意义,认为吉林南部早侏罗世时期位于濒古太平洋带,气候温暖潮湿,有利于苏铁类繁茂生长.

  6. 苏铁类珊瑚根内藻胞层的解剖观察%The Anatomical Observation about the Cell Layer with Blue-green Algae in the Coralloid Root of Cycads

    Institute of Scientific and Technical Information of China (English)

    苏建英; 李楠; 廖芬

    2007-01-01

    通过对苏铁类隶属10属,25种植物的珊瑚根进行了解剖观察,本文主要从解剖学角度阐述了苏铁类珊瑚根中共生藻的侵染途径、部位、以及藻胞层的发生发展,并根据观察结果分析讨论其共生藻与苏铁类根的共生关系.

  7. New Model for Electron Flow for Sulfate Reduction in Desulfovibrio alaskensis G20

    Energy Technology Data Exchange (ETDEWEB)

    Keller, Kimberly L.; Rapp-Giles, Barbara J.; Semkiw, Elizabeth S.; Porat, Iris; Brown, Steven D.; Wall, Judy D.

    2014-02-01

    To understand the energy conversion activities of the anaerobic sulfate-reducing bacteria, it is necessary to identify the components involved in electron flow. The importance of the abundant type I tetraheme cytochrome c3 (TpIc3) as an electron carrier during sulfate respiration was questioned by the previous isolation of a null mutation in the gene encoding TpIc3, cycA, in Desulfovibrio alaskensis G20. Whereas respiratory growth of the CycA mutant with lactate and sulfate was little affected, growth with pyruvate and sulfate was significantly impaired. We have explored the phenotype of the CycA mutant through physiological tests and transcriptomic and proteomic analyses. Data reported here show that electrons from pyruvate oxidation do not reach adenylyl sulfate reductase, the enzyme catalyzing the first redox reaction during sulfate reduction, in the absence of either CycA or the type I cytochrome c3:menaquinone oxidoreductase transmembrane complex, QrcABCD. In contrast to the wild type, the CycA and QrcA mutants did not grow with H2 or formate and sulfate as the electron acceptor. Transcriptomic and proteomic analyses of the CycA mutant showed that transcripts and enzymes for the pathway from pyruvate to succinate were strongly decreased in the CycA mutant regardless of the growth mode. Neither the CycA nor the QrcA mutant grew on fumarate alone, consistent with the omics results and a redox regulation of gene expression. We conclude that TpIc3 and the Qrc complex are D. alaskensis components essential for the transfer of electrons released in the periplasm to reach the cytoplasmic adenylyl sulfate reductase and present a model that may explain the CycA phenotype through confurcation of electrons.

  8. New Model for Electron Flow for Sulfate Reduction in Desulfovibrio alaskensis G20

    Energy Technology Data Exchange (ETDEWEB)

    Rapp-Giles, Barbara J [University of Missouri, Columbia; Keller, Kimberly L [University of Missouri, Columbia; Porat, Iris [ORNL; Brown, Steven D [ORNL; Semkiw, Elizabeth M. [University of Missouri; Wall, Judy D. [University of Missouri

    2014-01-01

    To understand the energy conversion activities of the anaerobic sulfate-reducing bacteria, it is necessary to identify the components involved in electron flow. The importance of the abundant type I tetraheme cytochrome c3 (TpIc3) as an electron carrier during sulfate respiration was questioned by the previous isolation of a null mutation in the gene encoding TpIc3, cycA, in Desulfovibrio alaskensis G20. Whereas respiratory growth of the CycA mutant with lactate and sulfate was little affected, growth with pyruvate and sulfate was significantly impaired. We have explored the phenotype of the CycA mutant through physiological tests and transcriptomic and proteomic analyses. Data reported here show that electrons from pyruvate oxidation do not reach adenylyl sulfate reductase, the enzyme catalyzing the first redox reaction during sulfate reduction, in the absence of either CycA or the type I cytochrome c3:menaquinone oxidoreductase transmembrane complex, QrcABCD. In contrast to the wild type, the CycA and QrcA mutants did not grow with H2 or formate and sulfate as the electron acceptor. Transcriptomic and proteomic analyses of the CycA mutant showed that transcripts and enzymes for the pathway from pyruvate to succinate were strongly decreased in the CycA mutant regardless of the growth mode. Neither the CycA nor the QrcA mutant grew on fumarate alone, consistent with the omics results and a redox regulation of gene expression. We conclude that TpIc3 and the Qrc complex are D. alaskensis components essential for the transfer of electrons released in the periplasm to reach the cytoplasmic adenylyl sulfate reductase and present a model that may explain the CycA phenotype through confurcation of electrons.

  9. Examining the interaction of apo E and neurotoxicity on a murine model of ALS-PDC.

    Science.gov (United States)

    Wilson, J M B; Petrik, M S; Moghadasian, M H; Shaw, C A

    2005-02-01

    Epidemiological studies have shown a positive relationship between cycad flour consumption and the development of the neurodegenerative disorder, amyotrophic lateral sclerosis - parkinsonism - dementia complex (ALS-PDC). Apolipoprotein E (apo E) allele variations have been associated with genetic susceptibility in neurodegenerative diseases, including ALS-PDC. We have studied cycad toxicity in a mouse model of ALS-PDC with a particular interest in its impact on the central nervous system (CNS) in both apo E knock-out (KO) mice and their wild-type (WT) counterparts. Behavioral motor tests, motor neuron counts, and immunohistochemical staining in brain and spinal cord, as well as routine histological examinations on internal organs, were performed to evaluate cycad toxicity. Plasma cholesterol levels were also measured before and during the study. Cycad treatment was associated with higher levels of plasma cholesterol only in apo E KO mice; increased levels of plasma cholesterol did not result in increased athero genesis. Cycad-fed wild-type mice developed progressive behavioral deficits including ALS-PDC-like pathological outcomes, while cycad-fed apo E KO mice were not significantly affected. Cycad-fed wild-type mice had shorter gait length measurements along with higher active caspase-3 levels in the striatum, substantia nigra, primary motor cortex, and spinal cord as compared with corresponding controls. These changes were associated with decreased labeling for glutamate transporter 1B and tyrosine hydroxylase activity levels. No evidence of cycad toxicity was observed in internal organs of either wild-type or apo E KO mice. Our data demonstrate that apo E KO mice are less susceptible to cycad toxicity, suggesting a role for apo E as a possible genetic susceptibility factor for some forms of toxin-induced neurodegeneration.

  10. Is Neurodegenerative Disease a Long-Latency Response to Early-Life Genotoxin Exposure?

    Directory of Open Access Journals (Sweden)

    Glen E. Kisby

    2011-09-01

    Full Text Available Western Pacific amyotrophic lateral sclerosis and parkinsonism-dementia complex, a disappearing neurodegenerative disease linked to use of the neurotoxic cycad plant for food and/or medicine, is intensively studied because the neuropathology (tauopathy is similar to that of Alzheimer’s disease. Cycads contain neurotoxic and genotoxic principles, notably cycasin and methylazoxymethanol, the latter sharing chemical relations with nitrosamines, which are derived from nitrates and nitrites in preserved meats and fertilizers, and also used in the rubber and leather industries. This review includes new data that influence understanding of the neurobiological actions of cycad and related genotoxins and the putative mechanisms by which they might trigger neurodegenerative disease.

  11. A New Model for Electron Flow for Sulfate Reduction in Desulfovibrio alaskensis G20

    Energy Technology Data Exchange (ETDEWEB)

    Keller, Kimberly L [University of Missouri, Columbia; Rapp-Giles, Barbara J [University of Missouri, Columbia; Semkiw, Elizabeth M. [University of Missouri; Porat, Iris [ORNL; Brown, Steven D [ORNL; Wall, Judy D. [University of Missouri

    2013-01-01

    To understand the energy conversion activities of the anaerobic sulfate-reducing bacteria, it is necessary to identify the components involved in electron flow. The importance of the abundant type I tetraheme cytochrome c3 (TpIc3) as an electron carrier during sulfate respiration was questioned by the previous isolation of a null mutation in the encoding gene, cycA, in Desulfovibrio alaskensis G20. Whereas respiratory growth of the CycA mutant with lactate and sulfate was little affected, growth with pyruvate and sulfate was significantly impaired. We have explored the phenotype of the CycA mutant through physiological tests and transcriptomic and proteomic analyses. Data reported here show that electrons from pyruvate oxidation do not reach adenylyl sulfate reductase, the enzyme catalyzing the first redox reaction during sulfate reduction, in the absence of either CycAor the type I cytochrome c3:menaquinone oxidoreductase, QrcABCD transmembrane complex. In contrast to the wild type, neither CycA and QrcA mutants do not grow with H2 or formate and sulfate as electron acceptor. Transcriptomic and proteomic analyses of the CycA mutant showed that transcripts and enzymes for the pathway from pyruvate to succinate were strongly decreased in the CycA mutant regardless of growth mode. Neither the CycA nor the QrcA mutant grew on fumarate alone, consistent with the omics results and a redox regulation of gene expression. We conclude that TpIc3 and the Qrc complex are essential D. alaskensis components for transfer of electrons released in the periplasm to reach the cytoplasmic adenylyl sulfate reductase and present a model that may explain the CycA phenotype through confurcation of electrons.

  12. The shady side of leaf development

    DEFF Research Database (Denmark)

    Merelo, Paz; Botterweg Paredes, Esther; Heisler, Marcus G.;

    2017-01-01

    regulatory network determines ad-/abaxial polarity in Arabidopsis thaliana leaves, where the Class III Homeodomain Leucine Zipper (HD-ZIPIII) and KANADI (KAN) proteins are key mediators. The HD-ZIPIII REVOLUTA (REV) is expressed in the adaxial domain of lateral organs, whereas KAN1 is involved in abaxial...

  13. 珍稀濒危植物贵州苏铁种子形态特性的数值分析%Numerical Analysis on Seed Morphology Characteristics for the Rare and Endangered Plant of Cycas guizhouensis Lan et R.F.Zou

    Institute of Scientific and Technical Information of China (English)

    刘兰; 黄小柱; 潘德权; 罗在柒

    2014-01-01

    通过测试不同野生居群贵州苏铁种子质量和形态性状特征,经方差分析、Tukey法多重比较、1%显著性检验,结果得到种子的长度显著性水平较高,其中去除外种皮后显著性更高,成熟贵州苏铁种子外形近圆球形;去除外种皮后种子特征能更好体现贵州苏铁种子型态特性,95%置信区间分析结果得到单粒重5.0822~5.5517g,种长、种宽、种高分别为22.832 7~23.606 3 mm、20.063 5 ~ 20.672 8 mm和18.481 4~ 19.028 6mm,呈卵圆形.研究结果为有效鉴定贵州苏铁物种种实特性提供基础数据.

  14. A new species of Aulacaspis Cockerell, 1893 from China with a key to Chinese species (Hemiptera, Coccoidea, Diaspididae

    Directory of Open Access Journals (Sweden)

    Jiufeng Wei

    2016-09-01

    Full Text Available A new species of armored scale insect, Aulacaspis zunyiensis sp. n. is described and illustrated from collections on cycads in China. A key to the Aulacaspis species known from China is provided.

  15. A new species of Aulacaspis Cockerell, 1893 from China with a key to Chinese species (Hemiptera, Coccoidea, Diaspididae)

    Science.gov (United States)

    Wei, Jiufeng; Jing, Xiaopeng; Zhang, Hufang

    2016-01-01

    Abstract A new species of armored scale insect, Aulacaspis zunyiensis sp. n. is described and illustrated from collections on cycads in China. A key to the Aulacaspis species known from China is provided. PMID:27829787

  16. High Host Specificity in Encarsia diaspidicola (Hymenoptera: Aphelinidae), a Biological Control Candidate Against the White Peach Scale in Hawaii

    Science.gov (United States)

    Pre-introductory host specificity tests were performed with Encarsia diaspidicola, a biological control candidate against the invasive white peach scale, Pseudaulacaspis pentagona. False oleander scale, P. cockerelli, coconut scale, Aspidiotus destructor, cycad scale, Aulacaspis yasumatsui, greenh...

  17. DsdX is the second D-serine transporter in uropathogenic Escherichia coli clinical isolate CFT073.

    Science.gov (United States)

    Anfora, Andrew T; Welch, Rodney A

    2006-09-01

    d-Serine is an amino acid present in mammalian urine that is inhibitory to Escherichia coli strains lacking a functional dsdA gene. Counterintuitively, a dsdA strain of E. coli clinical isolate CFT073 hypercolonizes the bladder and kidneys of mice relative to wild type during a coinfection in the murine model of urinary tract infection. We are interested in the mechanisms for uptake of d-serine in CFT073. d-Serine enters E. coli K-12 via CycA, the d-alanine transporter and d-cycloserine sensitivity locus. CFT073 cycA can grow on minimal medium with d-serine as a sole carbon source. The dsdX gene of the dsdCXA locus is a likely candidate for an additional d-serine transporter based on its predicted amino acid sequence similarity to gluconate transporters. In minimal medium, CFT073 dsdX can grow on d-serine as a sole carbon source; however, CFT073 dsdX cycA cannot. Additionally, CFT073 dsdXA cycA is not sensitive to inhibitory concentrations of d-serine during growth on glycerol and d-serine minimal medium. d-[(14)C]serine uptake experiments with CFT073 dsdX cycA harboring dsdX or cycA recombinant plasmids confirm that d-serine is able to enter E. coli cells via CycA or DsdX. In whole-cell d-[(14)C]serine uptake experiments, DsdX has an apparent K(m) of 58.75 microM and a V(max) of 75.96 nmol/min/mg, and CycA has an apparent K(m) of 82.40 microM and a V(max) of 58.90 nmol/min/mg. Only d-threonine marginally inhibits DsdX-mediated d-serine transport, whereas d-alanine, glycine, and d-cycloserine inhibit CycA-mediated d-serine transport. DsdX or CycA is sufficient to transport physiological quantities of d-serine, but DsdX is a d-serine-specific permease.

  18. The carp-goldfish nucleocytoplasmic hybrid has mitochondria from the carp as the nuclear donor species.

    Science.gov (United States)

    Hu, Guangfu; Zou, Guiwei; Liu, Xiangjiang; Liang, Hongwei; Li, Zhong; Hu, Shaona

    2014-02-25

    It is widely accepted that mitochondria and its DNA (mtDNA) exhibit strict maternal inheritance, with sperm contributing no or non-detectable mitochondria to the next generation. In fish, nuclear transfer (NT) through the combination of a donor nucleus and an enucleated oocyte can produce fertile nucleocytoplasmic hybrids (NCHs) even between different genera and subfamilies. One of the best studied fish NCHs is CyCa produced by transplanting the nuclei plus cytoplasm from the common carp (Cyprinus carpio var. wuyuanensis) into the oocytes of the wild goldfish (Carassius auratus), which has been propagated by self-mating for three generations. These NCH fish thus provide a unique model to study the origin of mitochondria. Here we report the complete mtDNA sequence of the CyCa hybrid and its parental species carp and goldfish as nuclear donor and cytoplasm host, respectively. Interestingly, the mtDNA of NCH fish CyCa is 99.69% identical to the nuclear donor species carp, and 89.25% identical to the oocyte host species goldfish. Furthermore, an amino acid sequence comparison of 13 mitochondrial proteins reveals that CyCa is 99.68% identical to the carp and 87.68% identical to the goldfish. On an mtDNA-based phylogenetic tree, CyCa is clustered with the carp but separated from the goldfish. A real-time PCR analysis revealed the presence of carp mtDNA but the absence of goldfish mtDNA. These results demonstrate--for the first time to our knowledge--that the mtDNA of a NCH such as CyCa fish may originate from its nuclear donor rather than its oocyte host.

  19. Major histocompatibility (MH) class II ß gene polymorphism influences disease resistance of common carp (Cyprinus carpio L.)

    NARCIS (Netherlands)

    Rakus, K.L.; Wiegertjes, G.F.; Jurecka, P.M.; Walker, P.D.; Pilarczyk, A.; Irnazarow, I.

    2009-01-01

    Genes of the major histocompatibility complex (MHC) are crucial elements of adaptive immunity. High polymorphism renders the MHC genes highly suitable for studies on association with disease resistance. In common carp (Cyprinus carpio L.), there are two paralogous groups of MH class II B genes, Cyca

  20. Hepatitis C virus non-structural 5B protein interacts with cyclin A2 and regulates viral propagation

    DEFF Research Database (Denmark)

    Pham, Long; Ngo, HT; Lim, YS

    2012-01-01

    Background & Aims Hepatitis C virus (HCV) requires host cellular proteins for its own propagation. To identify the cellular factors necessary for HCV propagation, we have recently screened the small interfering RNA (siRNA) library targeting cell cycle genes using cell culture grown HCV (HCVcc......, in vitro and in vivo protein binding assays, luciferase reporter gene assay, and immunoblot assay. Results We showed that siRNA-mediated depletion of CycA2 significantly inhibited HCV replication in both HCV subgenomic replicon cells and HCVcc-infected cells. Furthermore, HCV non-structural 5B (NS5B......) specifically interacted with CycA2 in vitro and in vivo. Protein interaction was mediated through the cyclin box of CycA2 and the palm domain of NS5B. We further showed that R/HxL motif in the palm domain of HCV NS5B mediated protein interaction with CycA2 and this interaction was necessary for HCV replication...

  1. Spatial reorganization of the endoplasmic reticulum during mitosis relies on mitotic kinase cyclin A in the early Drosophila embryo.

    Science.gov (United States)

    Bergman, Zane J; Mclaurin, Justin D; Eritano, Anthony S; Johnson, Brittany M; Sims, Amanda Q; Riggs, Blake

    2015-01-01

    Mitotic cyclin-dependent kinase with their cyclin partners (cyclin:Cdks) are the master regulators of cell cycle progression responsible for regulating a host of activities during mitosis. Nuclear mitotic events, including chromosome condensation and segregation have been directly linked to Cdk activity. However, the regulation and timing of cytoplasmic mitotic events by cyclin:Cdks is poorly understood. In order to examine these mitotic cytoplasmic events, we looked at the dramatic changes in the endoplasmic reticulum (ER) during mitosis in the early Drosophila embryo. The dynamic changes of the ER can be arrested in an interphase state by inhibition of either DNA or protein synthesis. Here we show that this block can be alleviated by micro-injection of Cyclin A (CycA) in which defined mitotic ER clusters gathered at the spindle poles. Conversely, micro-injection of Cyclin B (CycB) did not affect spatial reorganization of the ER, suggesting CycA possesses the ability to initiate mitotic ER events in the cytoplasm. Additionally, RNAi-mediated simultaneous inhibition of all 3 mitotic cyclins (A, B and B3) blocked spatial reorganization of the ER. Our results suggest that mitotic ER reorganization events rely on CycA and that control and timing of nuclear and cytoplasmic events during mitosis may be defined by release of CycA from the nucleus as a consequence of breakdown of the nuclear envelope.

  2. Spatial Reorganization of the Endoplasmic Reticulum during Mitosis Relies on Mitotic Kinase Cyclin A in the Early Drosophila Embryo

    Science.gov (United States)

    Bergman, Zane J.; Mclaurin, Justin D.; Eritano, Anthony S.; Johnson, Brittany M.; Sims, Amanda Q.; Riggs, Blake

    2015-01-01

    Mitotic cyclin-dependent kinase with their cyclin partners (cyclin:Cdks) are the master regulators of cell cycle progression responsible for regulating a host of activities during mitosis. Nuclear mitotic events, including chromosome condensation and segregation have been directly linked to Cdk activity. However, the regulation and timing of cytoplasmic mitotic events by cyclin:Cdks is poorly understood. In order to examine these mitotic cytoplasmic events, we looked at the dramatic changes in the endoplasmic reticulum (ER) during mitosis in the early Drosophila embryo. The dynamic changes of the ER can be arrested in an interphase state by inhibition of either DNA or protein synthesis. Here we show that this block can be alleviated by micro-injection of Cyclin A (CycA) in which defined mitotic ER clusters gathered at the spindle poles. Conversely, micro-injection of Cyclin B (CycB) did not affect spatial reorganization of the ER, suggesting CycA possesses the ability to initiate mitotic ER events in the cytoplasm. Additionally, RNAi-mediated simultaneous inhibition of all 3 mitotic cyclins (A, B and B3) blocked spatial reorganization of the ER. Our results suggest that mitotic ER reorganization events rely on CycA and that control and timing of nuclear and cytoplasmic events during mitosis may be defined by release of CycA from the nucleus as a consequence of breakdown of the nuclear envelope. PMID:25689737

  3. Liu et al., Afr J Tradit Complement Altern Med. (2013) 10(4):78-82 ...

    African Journals Online (AJOL)

    AJTCAM

    The effects of two types of extracts on gastric cancer cells were compared; dry ... to measure the cell protein contents and to make a comprehensive comparison. ... Tie Shu Ye is a plant in the genus Cycas in family Cycadaceae; its Latin .... Effect of Yangqi decoction patch on apoptosis of gastric cancer cells in animal model.

  4. A novel additional group II intron distinguishes the mitochondrial rps3 gene in gymnosperms.

    Science.gov (United States)

    Regina, Teresa M R; Picardi, Ernesto; Lopez, Loredana; Pesole, Graziano; Quagliariello, Carla

    2005-02-01

    Comparative analysis of the ribosomal protein S3 gene (rps3) in the mitochondrial genome of Cycas with newly sequenced counterparts from Magnolia and Helianthus and available sequences from higher plants revealed that the positional clustering with the genes for ribosomal protein S19 (rps19) and L16 (rpl16) is preserved in gymnosperms. However, in contrast to the other land plant species, the rps3 gene in Cycas mitochondria is unique in possessing a second intron: rps3i2. Reverse transcription-polymerase chain reaction (RT-PCR) analysis of the transcripts generated from the rps19-rps3-rpl16 cluster in Cycas mitochondria demonstrated that the genes are cotranscribed and extensively modified by RNA editing and that both introns are efficiently spliced. Despite remarkable size heterogeneity, the Cycas rps3i1 can be shown to be homologous to the group IIA introns present within the rps3 gene of algae and land plants, including Magnolia and Helianthus. Conversely, sequences similar to the rps3i2 have not been reported previously. On the basis of conserved primary and secondary structure the second intervening sequence interrupting the Cycas rps3 gene has been classified as a group II intron. The close relationship of the rps3i2 to a group of different plant mitochondrial introns is intriguing and suggestive of a mitochondrial derivation for this novel intervening sequence. Interestingly, the rps3i2 appears to be conserved at the same gene location in other gymnosperms. Furthermore, the pattern of the rps3i2 distribution among algae and land plants provides evidence for the evolutionary acquisition of this novel intron in gymnosperms via intragenomic transposition or retrotransposition.

  5. [A preliminary study on the molecular characteristics of D-cycloserine resistance of Mycobacterium tuberculosis].

    Science.gov (United States)

    Li, C; Li, G L; Luo, Q; Li, S J; Wang, R B; Lou, Y L; Lyu, J X; Wan, K L

    2017-02-10

    Objective: To investigate the relationship between D-cycloserine resistance and the gene mutations of alrA, ddlA and cycA of Mycobacterium (M.) tuberculosis, as well as the association between D-cycloserine resistance and spoligotyping genotyping. Methods: A total of 145 M. tuberculosis strains were selected from the strain bank. D-cycloserine resistant phenotypes of the strains were determined by the proportion method and the minimal inhibitory concentration was determined by resazurin microtiter assay. PCR amplification and DNA direct sequencing methods were used for the analysis of gene mutations. Relationship between the resistance phenotype and genotype was analyzed by chi-square test. Results: Of the 145 clinically collected strains, 24 (16.6%) of them were D-cycloserine resistant and 121 (83.4%) were sensitive. There were only synonymous mutations noticed on alrA, ddlA and cycA in sensitive strains. Of the 24 D-cycloserine resistant strains, 3 (12.5%) isolates' cycA and 1 (4.2%) isolates' alrA happened to be non-synonymous mutations, in which the codes were 188, 318 and 508 of cycA, and 261 of alrA, respectively. Results on drug sensitivity tests confirmed the minimal inhibitory concentration of the mutant strains were all increased to some degrees. The D-cycloserine resistant rates of 88 Beijing genotype and 57 non-Beijing genotype strains were 20.5% and 10.5% , respectively, but with no statistically significant difference (χ(2) =2.47, P>0.05). Conclusions: The non-synonymous mutations of alrA and cycA might contribute to one of the mechanisms of M. tuberculosis D-cycloserine resistance. M. tuberculosis Beijing genotype or non-Beijing genotype was not considered to be associated with the D-cycloserine resistance.

  6. Foliicolous microfungi occurring on Encephalartos

    NARCIS (Netherlands)

    Crous, PW.; Wood, A.R.; Okada, G.; Groenewald, J.Z.

    2008-01-01

    Species of Encephalartos, commonly known as bread trees, bread palms or cycads are native to Africa; the genus encompasses more than 60 species and represents an important component of the indigenous African, flora. Recently, a leaf blight disease was noted on several E. altensteinii plants growing

  7. Foliicolous microfungi occurring on Encephalartos

    NARCIS (Netherlands)

    Crous, P.W.; Wood, A.R.; Okada, G.; Groenewald, J.Z.

    2008-01-01

    Species of Encephalartos, commonly known as bread trees, bread palms or cycads are native to Africa; the genus encompasses more than 60 species and represents an important component of the indigenous African flora. Recently, a leaf blight disease was noted on several E. altensteinii plants growing a

  8. Exine ultrastructure of in situ pollen from the cycadalean cone Androstrobus prisma Thomas et Harris 1960 from the Jurassic of England

    NARCIS (Netherlands)

    Zavialova, N.; van Konijnenburg-van Cittert, J.H.A.

    2012-01-01

    Pollen grains extracted from the cycad pollen cone Androstrobus prisma Thomas et Harris 1960 from the Bajocian of Yorkshire were studied by means of LM, SEM and TEM. The species is characterized by rounded-oval, inaperturate pollen with an indistinctly verrucate surface and predominantly homogeneous

  9. The typification of Zamia erosa and the priority of that name over Z. amblyphyllidia

    Science.gov (United States)

    Three distinctive cycads are found on Puerto Rico, which have been treated as three species: Z. amblyphyllidia, found on the north coast, and Z. portoricensis and Z. pumila, both found in the south. We investigated the population genetics of these species with ten DNA markers across seven populatio...

  10. Phylogeography and conservation genetics of the Caribbean Zamia clade: an integrated systematic approach with SSRs and single copy nuclear genes

    Science.gov (United States)

    The Zamia pumila L. complex (Cycadales: Zamiaceae) is a monophyletic, diploid (2n = 16) and distinctive assemblage of cycad populations restricted to the West Indies and southeastern U. S. that has been treated as comprising one to nine species. Our research project seeks to simultaneously investi...

  11. Exine ultrastructure of in situ pollen from the cycadalean cone Androstrobus prisma Thomas et Harris 1960 from the Jurassic of England

    NARCIS (Netherlands)

    Zavialova, N.; van Konijnenburg-van Cittert, J.H.A.

    2012-01-01

    Pollen grains extracted from the cycad pollen cone Androstrobus prisma Thomas et Harris 1960 from the Bajocian of Yorkshire were studied by means of LM, SEM and TEM. The species is characterized by rounded-oval, inaperturate pollen with an indistinctly verrucate surface and predominantly homogeneous

  12. 7 CFR 301.92-1 - Definitions.

    Science.gov (United States)

    2010-01-01

    ..., or field grown cycads, and tissue culture plants grown in vitro; and plants meeting the definition of... restricted articles in accordance with part 330 of this chapter. Person. Any association, company, corporation, firm, individual, joint stock company, partnership, society, or other entity. Plant...

  13. Taeniopterid lamina on Phasmatocycas megasporophylls (Cycadales) from the Lower Permian of Kansas, U.S.A.

    Science.gov (United States)

    Gillespie, W.H.; Pfefferkorn, H.W.

    1986-01-01

    New specimens of Phasmatocycas and Taeniopteris from the original Lower Permian locality in Kansas demonstrate organic attachment of the two and corroborate Mamay's hypothesis that Phasmatocycas and Taeniopteris were parts of the same plant. These forms also suggest that cycads evolved from taxa with entire leaves; i.e. Taeniopteris, rather than from pteridosperms with compound leaves. ?? 1986.

  14. Organization of the electron transfer chain to oxygen in the obligate human pathogen Neisseria gonorrhoeae: roles for cytochromes c4 and c5, but not cytochrome c2, in oxygen reduction.

    Science.gov (United States)

    Li, Ying; Hopper, Amanda; Overton, Tim; Squire, Derrick J P; Cole, Jeffrey; Tovell, Nicholas

    2010-05-01

    Although Neisseria gonorrhoeae is a prolific source of eight c-type cytochromes, little is known about how its electron transfer pathways to oxygen are organized. In this study, the roles in the respiratory chain to oxygen of cytochromes c(2), c(4), and c(5), encoded by the genes cccA, cycA, and cycB, respectively, have been investigated. Single mutations in genes for either cytochrome c(4) or c(5) resulted in an increased sensitivity to growth inhibition by excess oxygen and small decreases in the respiratory capacity of the parent, which were complemented by the chromosomal integration of an ectopic, isopropyl-beta-d-thiogalactopyranoside (IPTG)-inducible copy of the cycA or cycB gene. In contrast, a cccA mutant reduced oxygen slightly more rapidly than the parent, suggesting that cccA is expressed but cytochrome c(2) is not involved in electron transfer to cytochrome oxidase. The deletion of cccA increased the sensitivity of the cycB mutant to excess oxygen but decreased the sensitivity of the cycA mutant. Despite many attempts, a double mutant defective in both cytochromes c(4) and c(5) could not be isolated. However, a strain with the ectopically encoded, IPTG-inducible cycB gene with deletions in both cycA and cycB was constructed: the growth and survival of this strain were dependent upon the addition of IPTG, so gonococcal survival is dependent upon the synthesis of either cytochrome c(4) or c(5). These results define the gonococcal electron transfer chain to oxygen in which cytochromes c(4) and c(5), but not cytochrome c(2), provide alternative pathways for electron transfer from the cytochrome bc(1) complex to the terminal oxidase cytochrome cbb(3).

  15. Hydrophobia of gymnosperms: myth or reality? A global analysis

    OpenAIRE

    Kozlowski, Gregor; Stoffel, Markus; Bétrisey, Sébastien; Cardinaux, Léonard; Mota, Matteo

    2014-01-01

    According to the classical textbooks, the gymnosperms are the only seed plants without aquatic species. Recently, however, a set of virtually complete compilations on gymnosperms has been published, enabling a new evaluation of the putative hydrophobia of gymnosperms. This synthesis aims at portraying the relation of all extant gymnosperm species to aquatic and wetland habitats. We present a database of all 986 extant gymnosperm species with their ecological characteristics including 291 cyca...

  16. Numerical taxonomy of the genus Matthiola (Brassicaceae in Northeast of Iran based on morphological traits

    Directory of Open Access Journals (Sweden)

    Mozhgan Rashid Taranloo

    2014-01-01

    Full Text Available The genus Matthiola R. BR. (Brassicaceae consists of 48 species in the Iranian plateau, of which only seven species are distributed in northeast of Iran. Six species erre collected from the region under study including M. afghanica, M. alyssifolia, M. chenopodiifolia, M. chorassanica, M. dumulosa and M. farinose. Two species, M. flavida and M. revoluta were recorded for the first time in this study. Some specimens of an unknown taxon entitled Matthiola sp. are also collected in the region and included in the present study. In this study, we tried to use a set of morphologically informative characters which could determine species boundaries and also provide appropriate identification key to the genus in the northeast of Iran. 71 morphological features including quantitative and qualitative were examined on 68 herbarium and field-collected accessions followed by statistical analyses. The results of the univariate analysis indicated that "presence/absence of trichome on the stem and leaf" and "presence/absence of glandular trichomes on the sepal and pedicel" did not significantly differentiate the species and they were excluded from the subsequent analysis. The results of multivariate analysis showed that the species under study were grouped within three groups. First group included specimens of the species M. alyssifolia, the species M. afghanica, M. chenopodiifolia, M. dumulosa, M. farinosa, M. flavida and Matthiola sp. were placed in second group and third group included specimens of the two species M. chorassanica and M. revoluta.

  17. Conservation of class C function of floral organ development during 300 million years of evolution from gymnosperms to angiosperms.

    Science.gov (United States)

    Zhang, Pingyu; Tan, Hugh T W; Pwee, Keng-Hock; Kumar, Prakash P

    2004-02-01

    Flower development in angiosperms is regulated by the family of MADS-box transcription factors. MADS-box genes have also been reported from gymnosperms, another major group of seed plants. AGAMOUS (AG) is the class C MADS-box floral organ identity gene controlling the stamen and carpel development in Arabidopsis. We report the characterization of an ortholog of the AG gene, named Cycas AGAMOUS (CyAG), from the primitive gymnosperm Cycas edentata. The expression pattern of CyAG in Cycas parallels that of AG in Arabidopsis. Additionally, the gene structure, including the number and location of the introns, is conserved in CyAG and other AG orthologs known. Most importantly, functional analysis shows that CyAG driven by the AG promoter can rescue the loss-of-function ag mutant of Arabidopsis. However, the ectopic expression of CyAG in ag mutant Arabidopsis cannot produce the carpeloid and stamenoid organs in the first and second whorls, although the stamen and carpel are rescued in the third and fourth whorls of the transformants. These observations show that the molecular mechanism of class C function controlling reproductive organ identity (stamen and carpel of angiosperms or microsporophyll and megasporophyll of gymnosperms) arose before the divergence of angiosperms and gymnosperms, and has been conserved during 300 million years of evolution thereafter.

  18. Thrips pollination of Mesozoic gymnosperms.

    Science.gov (United States)

    Peñalver, Enrique; Labandeira, Conrad C; Barrón, Eduardo; Delclòs, Xavier; Nel, Patricia; Nel, André; Tafforeau, Paul; Soriano, Carmen

    2012-05-29

    Within modern gymnosperms, conifers and Ginkgo are exclusively wind pollinated whereas many gnetaleans and cycads are insect pollinated. For cycads, thrips are specialized pollinators. We report such a specialized pollination mode from Early Cretaceous amber of Spain, wherein four female thrips representing a genus and two species in the family Melanthripidae were covered by abundant Cycadopites pollen grains. These females bear unique ring setae interpreted as specialized structures for pollen grain collection, functionally equivalent to the hook-tipped sensilla and plumose setae on the bodies of bees. The most parsimonious explanation for this structure is parental food provisioning for larvae, indicating subsociality. This association provides direct evidence of specialized collection and transportation of pollen grains and likely gymnosperm pollination by 110-105 million years ago, possibly considerably earlier.

  19. Exploring Diversification and Genome Size Evolution in Extant Gymnosperms through Phylogenetic Synthesis

    Directory of Open Access Journals (Sweden)

    J. Gordon Burleigh

    2012-01-01

    Full Text Available Gymnosperms, comprising cycads, Ginkgo, Gnetales, and conifers, represent one of the major groups of extant seed plants. Yet compared to angiosperms, little is known about the patterns of diversification and genome evolution in gymnosperms. We assembled a phylogenetic supermatrix containing over 4.5 million nucleotides from 739 gymnosperm taxa. Although 93.6% of the cells in the supermatrix are empty, the data reveal many strongly supported nodes that are generally consistent with previous phylogenetic analyses, including weak support for Gnetales sister to Pinaceae. A lineage through time plot suggests elevated rates of diversification within the last 100 million years, and there is evidence of shifts in diversification rates in several clades within cycads and conifers. A likelihood-based analysis of the evolution of genome size in 165 gymnosperms finds evidence for heterogeneous rates of genome size evolution due to an elevated rate in Pinus.

  20. Excitatory amino acid b-N-methylamino-L-alanine is a putative environmental neurotoxin

    Directory of Open Access Journals (Sweden)

    VLADIMIR NEDELJKOV

    2011-04-01

    Full Text Available The amino acid b-N-methylamino-L-alanine (L-BMAA has been associated with the amyotrophic lateral sclerosis/parkinsonism-dementia complex in three distinct western Pacific populations. The putative neurotoxin is produced by cyanobacteria, which live symbiotically in the roots of cycad trees. L-BMAA was thought to be a threat only to those few populations whose diet and medicines rely heavily on cycad seeds. However, the recent discovery that cyanobacteria from diverse terrestrial, freshwater, and saltwater ecosystems around the world produce the toxin requires a reassessment of whether it poses a larger health threat. Therefore, it is proposed that monitoring L-BMAA levels in cyanobacteria-contaminated water supplies might be prudent.

  1. 世界苏铁植物名录

    Institute of Scientific and Technical Information of China (English)

    陈家瑞

    2005-01-01

    根据国内广大读者的要求,这里首次列出了世界苏铁植物名录。该名录主要是根据K.D.Hill,D.Wm.Stevenson and R.Osbortne2004年,由T.Walters and R.Osborne主编,由英国CAB International出版的《苏铁分类学》(Cycad Classification)书中的文章,(The World List of Cycads)翻译出,但其中未正式发表的分类群及文献未被列出。

  2. Reflections on the Visiting Professorship Programme for Senior International Scientists at CAS

    Institute of Scientific and Technical Information of China (English)

    Christopher Richard Hill

    2010-01-01

    @@ I first learnt about the Visiting Professorship Programme after visiting the Institute of Geology and Palaeontology of the Chinese Academy of Sciences in Nanjing during December 2009.I was asked to give a lecture on"missing links"amongst ancient Cycads and also met with staff of the Institute to learn about and discuss shared research interests from a joint Chinese and English perspective.

  3. Phylogenomics and coalescent analyses resolve extant seed plant relationships.

    Directory of Open Access Journals (Sweden)

    Zhenxiang Xi

    Full Text Available The extant seed plants include more than 260,000 species that belong to five main lineages: angiosperms, conifers, cycads, Ginkgo, and gnetophytes. Despite tremendous effort using molecular data, phylogenetic relationships among these five lineages remain uncertain. Here, we provide the first broad coalescent-based species tree estimation of seed plants using genome-scale nuclear and plastid data By incorporating 305 nuclear genes and 47 plastid genes from 14 species, we identify that i extant gymnosperms (i.e., conifers, cycads, Ginkgo, and gnetophytes are monophyletic, ii gnetophytes exhibit discordant placements within conifers between their nuclear and plastid genomes, and iii cycads plus Ginkgo form a clade that is sister to all remaining extant gymnosperms. We additionally observe that the placement of Ginkgo inferred from coalescent analyses is congruent across different nucleotide rate partitions. In contrast, the standard concatenation method produces strongly supported, but incongruent placements of Ginkgo between slow- and fast-evolving sites. Specifically, fast-evolving sites yield relationships in conflict with coalescent analyses. We hypothesize that this incongruence may be related to the way in which concatenation methods treat sites with elevated nucleotide substitution rates. More empirical and simulation investigations are needed to understand this potential weakness of concatenation methods.

  4. Phylogenomics and coalescent analyses resolve extant seed plant relationships.

    Science.gov (United States)

    Xi, Zhenxiang; Rest, Joshua S; Davis, Charles C

    2013-01-01

    The extant seed plants include more than 260,000 species that belong to five main lineages: angiosperms, conifers, cycads, Ginkgo, and gnetophytes. Despite tremendous effort using molecular data, phylogenetic relationships among these five lineages remain uncertain. Here, we provide the first broad coalescent-based species tree estimation of seed plants using genome-scale nuclear and plastid data By incorporating 305 nuclear genes and 47 plastid genes from 14 species, we identify that i) extant gymnosperms (i.e., conifers, cycads, Ginkgo, and gnetophytes) are monophyletic, ii) gnetophytes exhibit discordant placements within conifers between their nuclear and plastid genomes, and iii) cycads plus Ginkgo form a clade that is sister to all remaining extant gymnosperms. We additionally observe that the placement of Ginkgo inferred from coalescent analyses is congruent across different nucleotide rate partitions. In contrast, the standard concatenation method produces strongly supported, but incongruent placements of Ginkgo between slow- and fast-evolving sites. Specifically, fast-evolving sites yield relationships in conflict with coalescent analyses. We hypothesize that this incongruence may be related to the way in which concatenation methods treat sites with elevated nucleotide substitution rates. More empirical and simulation investigations are needed to understand this potential weakness of concatenation methods.

  5. High throughput screens yield small molecule inhibitors of Leishmania CRK3:CYC6 cyclin-dependent kinase.

    Directory of Open Access Journals (Sweden)

    Roderick G Walker

    Full Text Available BACKGROUND: Leishmania species are parasitic protozoa that have a tightly controlled cell cycle, regulated by cyclin-dependent kinases (CDKs. Cdc2-related kinase 3 (CRK3, an essential CDK in Leishmania and functional orthologue of human CDK1, can form an active protein kinase complex with Leishmania cyclins CYCA and CYC6. Here we describe the identification and synthesis of specific small molecule inhibitors of bacterially expressed Leishmania CRK3:CYC6 using a high throughput screening assay and iterative chemistry. We also describe the biological activity of the molecules against Leishmania parasites. METHODOLOGY/PRINCIPAL FINDINGS: In order to obtain an active Leishmania CRK3:CYC6 protein kinase complex, we developed a co-expression and co-purification system for Leishmania CRK3 and CYC6 proteins. This active enzyme was used in a high throughput screening (HTS platform, utilising an IMAP fluorescence polarisation assay. We carried out two chemical library screens and identified specific inhibitors of CRK3:CYC6 that were inactive against the human cyclin-dependent kinase CDK2:CycA. Subsequently, the best inhibitors were tested against 11 other mammalian protein kinases. Twelve of the most potent hits had an azapurine core with structure activity relationship (SAR analysis identifying the functional groups on the 2 and 9 positions as essential for CRK3:CYC6 inhibition and specificity against CDK2:CycA. Iterative chemistry allowed synthesis of a number of azapurine derivatives with one, compound 17, demonstrating anti-parasitic activity against both promastigote and amastigote forms of L. major. Following the second HTS, 11 compounds with a thiazole core (active towards CRK3:CYC6 and inactive against CDK2:CycA were tested. Ten of these hits demonstrated anti-parasitic activity against promastigote L. major. CONCLUSIONS/SIGNIFICANCE: The pharmacophores identified from the high throughput screens, and the derivatives synthesised, selectively

  6. RESEARCH CONCERNING THE CHEMICAL CONTROL AGAINST PSEUDOCOCCUS ADONIDUM L.

    Directory of Open Access Journals (Sweden)

    Maria ECOBICI

    2005-01-01

    Full Text Available Pseudococcus adonidum is a polyphag pest, which attacks different species of plants belonging to many genus and families, as: Citrus, Ficus, Cactaceae, Cycas, Dracena, Phoenix, Mimoza, Asparagus, Camellia etc. It is localized in large colonies on leaves, stems, branches, offshoots, and roots. The experiments were performed in solarium conditions during 2001-2002. Testing the efficiency of an insecticide sort was the aim of our experiment. During 2 experimental years, 9 products were tested: Confidor 200 SL, Calypso 400 SC; Pyrinex 25 EC, Vydate 10 G, Fastac 10 CE – RV, Sumithion 50 EC, Mospilan 20 SP, Decis 2,5 EC, Actellic 50 EC.

  7. Phylogeny and divergence times of gymnosperms inferred from single-copy nuclear genes.

    Science.gov (United States)

    Lu, Ying; Ran, Jin-Hua; Guo, Dong-Mei; Yang, Zu-Yu; Wang, Xiao-Quan

    2014-01-01

    Phylogenetic reconstruction is fundamental to study evolutionary biology and historical biogeography. However, there was not a molecular phylogeny of gymnosperms represented by extensive sampling at the genus level, and most published phylogenies of this group were constructed based on cytoplasmic DNA markers and/or the multi-copy nuclear ribosomal DNA. In this study, we use LFY and NLY, two single-copy nuclear genes that originated from an ancient gene duplication in the ancestor of seed plants, to reconstruct the phylogeny and estimate divergence times of gymnosperms based on a complete sampling of extant genera. The results indicate that the combined LFY and NLY coding sequences can resolve interfamilial relationships of gymnosperms and intergeneric relationships of most families. Moreover, the addition of intron sequences can improve the resolution in Podocarpaceae but not in cycads, although divergence times of the cycad genera are similar to or longer than those of the Podocarpaceae genera. Our study strongly supports cycads as the basal-most lineage of gymnosperms rather than sister to Ginkgoaceae, and a sister relationship between Podocarpaceae and Araucariaceae and between Cephalotaxaceae-Taxaceae and Cupressaceae. In addition, intergeneric relationships of some families that were controversial, and the relationships between Taxaceae and Cephalotaxaceae and between conifers and Gnetales are discussed based on the nuclear gene evidence. The molecular dating analysis suggests that drastic extinctions occurred in the early evolution of gymnosperms, and extant coniferous genera in the Northern Hemisphere are older than those in the Southern Hemisphere on average. This study provides an evolutionary framework for future studies on gymnosperms.

  8. Phylogeny and divergence times of gymnosperms inferred from single-copy nuclear genes.

    Directory of Open Access Journals (Sweden)

    Ying Lu

    Full Text Available Phylogenetic reconstruction is fundamental to study evolutionary biology and historical biogeography. However, there was not a molecular phylogeny of gymnosperms represented by extensive sampling at the genus level, and most published phylogenies of this group were constructed based on cytoplasmic DNA markers and/or the multi-copy nuclear ribosomal DNA. In this study, we use LFY and NLY, two single-copy nuclear genes that originated from an ancient gene duplication in the ancestor of seed plants, to reconstruct the phylogeny and estimate divergence times of gymnosperms based on a complete sampling of extant genera. The results indicate that the combined LFY and NLY coding sequences can resolve interfamilial relationships of gymnosperms and intergeneric relationships of most families. Moreover, the addition of intron sequences can improve the resolution in Podocarpaceae but not in cycads, although divergence times of the cycad genera are similar to or longer than those of the Podocarpaceae genera. Our study strongly supports cycads as the basal-most lineage of gymnosperms rather than sister to Ginkgoaceae, and a sister relationship between Podocarpaceae and Araucariaceae and between Cephalotaxaceae-Taxaceae and Cupressaceae. In addition, intergeneric relationships of some families that were controversial, and the relationships between Taxaceae and Cephalotaxaceae and between conifers and Gnetales are discussed based on the nuclear gene evidence. The molecular dating analysis suggests that drastic extinctions occurred in the early evolution of gymnosperms, and extant coniferous genera in the Northern Hemisphere are older than those in the Southern Hemisphere on average. This study provides an evolutionary framework for future studies on gymnosperms.

  9. A NEW GENUS OF CYCADALEAN PLANTS FROM THE EARLY TRIASSIC OF WESTERN LIAONING, CHINA--MEDIOCYCAS GEN. NOV. AND ITS EVOLUTIONARY SIGNIFICANCE%辽宁西部早三叠世苏铁植物一新属--Mediocycas gen. nov.及其演化意义

    Institute of Scientific and Technical Information of China (English)

    李楠; 傅晓平; 张武; 郑少林; 曹雨

    2005-01-01

    报道苏铁植物大孢子叶化石一新属--中间苏铁属(Mediocycas gen. nov.).标本采集于辽宁省西部,喀左县杨树沟煤矿后山的早三叠世红砬组. 这些标本以前曾被处理为疑问化石 (Problematicum).因当时资料不足,所以没有确定属种名称.但鉴于这些化石在苏铁类早期起源与演化研究中具有重要意义,故对它们作了重新研究.文中除了以喀左中间苏铁(Mediocycas kazuoensis gen. et sp. nov.)为典型种进行描述以外,还对新属、种在苏铁类起源与演化方面的意义作了较为详细的讨论.%A new genus--Mediocycas gen. nov. of fossil cycad megasporophylls is proposed based on the specimens collected from Yangshugou village, Kazuo county, western Liaoning Province, China. The stratum of plant-bearing bed belongs to the Lower Triassic Hongla Formation. The specimens were previously considered as a problematical fossil due to the lack of material. These fossils, however, are of vital importance in understanding the early evolution of cycads, and therefore worthy of reinvestigation. In the present paper, description of the typical species Mediocycas kazuoensis gen. et sp. nov. was made, and its important significance in the origin and early evolution of the megasporophyll of cycads was discussed.

  10. Phylogeny and Divergence Times of Gymnosperms Inferred from Single-Copy Nuclear Genes

    Science.gov (United States)

    Guo, Dong-Mei; Yang, Zu-Yu; Wang, Xiao-Quan

    2014-01-01

    Phylogenetic reconstruction is fundamental to study evolutionary biology and historical biogeography. However, there was not a molecular phylogeny of gymnosperms represented by extensive sampling at the genus level, and most published phylogenies of this group were constructed based on cytoplasmic DNA markers and/or the multi-copy nuclear ribosomal DNA. In this study, we use LFY and NLY, two single-copy nuclear genes that originated from an ancient gene duplication in the ancestor of seed plants, to reconstruct the phylogeny and estimate divergence times of gymnosperms based on a complete sampling of extant genera. The results indicate that the combined LFY and NLY coding sequences can resolve interfamilial relationships of gymnosperms and intergeneric relationships of most families. Moreover, the addition of intron sequences can improve the resolution in Podocarpaceae but not in cycads, although divergence times of the cycad genera are similar to or longer than those of the Podocarpaceae genera. Our study strongly supports cycads as the basal-most lineage of gymnosperms rather than sister to Ginkgoaceae, and a sister relationship between Podocarpaceae and Araucariaceae and between Cephalotaxaceae-Taxaceae and Cupressaceae. In addition, intergeneric relationships of some families that were controversial, and the relationships between Taxaceae and Cephalotaxaceae and between conifers and Gnetales are discussed based on the nuclear gene evidence. The molecular dating analysis suggests that drastic extinctions occurred in the early evolution of gymnosperms, and extant coniferous genera in the Northern Hemisphere are older than those in the Southern Hemisphere on average. This study provides an evolutionary framework for future studies on gymnosperms. PMID:25222863

  11. Plant macrofossils of the upper Cretaceous Kaitangata coalfield, New Zealand

    Energy Technology Data Exchange (ETDEWEB)

    Pole, M.; Douglas, B. [University of Queensland, Brisbane, Qld. (Australia). Dept. of Botany

    1999-08-15

    Uppermost Cretaceous sediments from the Cretaceous Kaitangata Coal Mine and the Wangaloa coast (south of Dunedin, New Zealand) were investigated for dispersed plant macrofossils. The gymnosperms include two cycads (Macrozamia sp. and Pterostoma sp.), Ginkgo sp., three further possible ginkgophyte taxa, and ten conifer taxa. The conifers include two new conifer genera and species, Maikuku stephaniae and Ware riderensis, which are placed in the Taxodiaceae s.l. There are also 13 types of angiosperm cuticle. Sample heterogeneity as regards taxa present and their abundance suggests taxonomic heterogeneity in the original vegetation.

  12. Fossil woods from the Late Cretaceous Aachen Formation.

    Science.gov (United States)

    Meijer

    2000-11-01

    Silicified fossil woods from the Late Cretaceous (Santonian) Aachen Formation of northeast Belgium, southernmost Netherlands and adjacent Germany were investigated. Gymnosperms dominate this assemblage: Taxodioxylon gypsaceum, T. cf. gypsaceum, T. cf. albertense (all Taxodiaceae), Dammaroxylon aachenense sp. nov. (Araucariaceae), Pinuxylon sp. (Pinaceae), and Scalaroxylon sp. (Cycad or Cycadeoid). Angiosperms are minor constituents: Nyssoxylon sp. (Nyssaceae?, Cornaceae?), Mastixioxylon symplocoides sp. nov. (Mastixiaceae?, Symplocaceae?), Plataninium decipiens (Platanaceae) and Paraphyllanthoxylon cf. marylandense (Anacardiaceae?, Burseraceae?, Lauraceae?).The composition of this assemblage and the anatomy of the woods indicate a seasonal and humid warm-temperate to subtropical climate.

  13. EST analysis in Ginkgo biloba: an assessment of conserved developmental regulators and gymnosperm specific genes

    Directory of Open Access Journals (Sweden)

    Runko Suzan J

    2005-10-01

    Full Text Available Abstract Background Ginkgo biloba L. is the only surviving member of one of the oldest living seed plant groups with medicinal, spiritual and horticultural importance worldwide. As an evolutionary relic, it displays many characters found in the early, extinct seed plants and extant cycads. To establish a molecular base to understand the evolution of seeds and pollen, we created a cDNA library and EST dataset from the reproductive structures of male (microsporangiate, female (megasporangiate, and vegetative organs (leaves of Ginkgo biloba. Results RNA from newly emerged male and female reproductive organs and immature leaves was used to create three distinct cDNA libraries from which 6,434 ESTs were generated. These 6,434 ESTs from Ginkgo biloba were clustered into 3,830 unigenes. A comparison of our Ginkgo unigene set against the fully annotated genomes of rice and Arabidopsis, and all available ESTs in Genbank revealed that 256 Ginkgo unigenes match only genes among the gymnosperms and non-seed plants – many with multiple matches to genes in non-angiosperm plants. Conversely, another group of unigenes in Gingko had highly significant homology to transcription factors in angiosperms involved in development, including MADS box genes as well as post-transcriptional regulators. Several of the conserved developmental genes found in Ginkgo had top BLAST homology to cycad genes. We also note here the presence of ESTs in G. biloba similar to genes that to date have only been found in gymnosperms and an additional 22 Ginkgo genes common only to genes from cycads. Conclusion Our analysis of an EST dataset from G. biloba revealed genes potentially unique to gymnosperms. Many of these genes showed homology to fully sequenced clones from our cycad EST dataset found in common only with gymnosperms. Other Ginkgo ESTs are similar to developmental regulators in higher plants. This work sets the stage for future studies on Ginkgo to better understand seed and

  14. 野生苏铁上发现曲纹紫灰蝶危害

    Institute of Scientific and Technical Information of China (English)

    高泽正; 谢振华; 韦强; 王少平; 简曙光

    2004-01-01

    苏铁植物(Cycads)早在2亿多年前的中生代就与恐龙并存于地球,是现存最古老的种子植物类群之一,它们对于研究种子植物的起源与演化、种子植物的区系与古气候、古地理的变迁等都具有重要意义;它们同时也是一类观赏价值很高的园艺植物,有很好的

  15. Aspergillus fumigatus mitochondrial electron transport chain mediates oxidative stress homeostasis, hypoxia responses, and fungal pathogenesis

    Science.gov (United States)

    Grahl, Nora; Dinamarco, Taisa Magnani; Willger, Sven D.; Goldman, Gustavo H.; Cramer, Robert A.

    2012-01-01

    Summary We previously observed that hypoxia is an important component of host microenvironments during pulmonary fungal infections. However, mechanisms of fungal growth in these in vivo hypoxic conditions are poorly understood. Here, we report that mitochondrial respiration is active in hypoxia (1% oxygen) and critical for fungal pathogenesis. We generated Aspergillus fumigatus alternative oxidase (aoxA) and cytochrome C (cycA) null mutants and assessed their ability to tolerate hypoxia, macrophage killing, and virulence. In contrast to ΔaoxA, ΔcycA was found to be significantly impaired in conidia germination, growth in normoxia and hypoxia, and displayed attenuated virulence. Intriguingly, loss of cycA results in increased levels of AoxA activity, which results in increased resistance to oxidative stress, macrophage killing, and long-term persistence in murine lungs. Thus, our results demonstrate a previously unidentified role for fungal mitochondrial respiration in the pathogenesis of aspergillosis, and lay the foundation for future research into its role in hypoxia signaling and adaptation. PMID:22443190

  16. Spire, an actin nucleation factor, regulates cell division during Drosophila heart development.

    Directory of Open Access Journals (Sweden)

    Peng Xu

    Full Text Available The Drosophila dorsal vessel is a beneficial model system for studying the regulation of early heart development. Spire (Spir, an actin-nucleation factor, regulates actin dynamics in many developmental processes, such as cell shape determination, intracellular transport, and locomotion. Through protein expression pattern analysis, we demonstrate that the absence of spir function affects cell division in Myocyte enhancer factor 2-, Tinman (Tin-, Even-skipped- and Seven up (Svp-positive heart cells. In addition, genetic interaction analysis shows that spir functionally interacts with Dorsocross, tin, and pannier to properly specify the cardiac fate. Furthermore, through visualization of double heterozygous embryos, we determines that spir cooperates with CycA for heart cell specification and division. Finally, when comparing the spir mutant phenotype with that of a CycA mutant, the results suggest that most Svp-positive progenitors in spir mutant embryos cannot undergo full cell division at cell cycle 15, and that Tin-positive progenitors are arrested at cell cycle 16 as double-nucleated cells. We conclude that Spir plays a crucial role in controlling dorsal vessel formation and has a function in cell division during heart tube morphogenesis.

  17. Speed versus endurance tradeoff in plants: Leaves with higher photosynthetic rates show stronger seasonal declines

    Science.gov (United States)

    Zhang, Yong-Jiang; Sack, Lawren; Cao, Kun-Fang; Wei, Xue-Mei; Li, Nan

    2017-01-01

    We tested for a tradeoff across species between plant maximum photosynthetic rate and the ability to maintain photosynthesis under adverse conditions in the unfavorable season. Such a trade-off would be consistent with the observed trade-off between maximum speed and endurance in athletes and some animals that has been explained by cost-benefit theory. This trend would have importance for the general understanding of leaf design, and would simplify models of annual leaf carbon relations. We tested for such a trade-off using a database analysis across vascular plants and using an experimental approach for 29 cycad species, representing an ancient plant lineage with diversified evergreen leaves. In both tests, a higher photosynthetic rate per mass or per area in the favorable season was associated with a stronger absolute or percent decline in the unfavorable season. We resolved a possible mechanism based on biomechanics and nitrogen allocation; cycads with high leaf toughness (leaf mass per area) and higher investment in leaf construction than in physiological function (C/N ratio) tended to have lower warm season photosynthesis but less depression in the cool season. We propose that this trade-off, consistent with cost-benefit theory, represents a significant physio-phenological constraint on the diversity and seasonal dynamics of photosynthetic rate. PMID:28186201

  18. In Silico Identification of Co-transcribed Core Cell Cycle Regulators and Transcription Factors in Arabidopsis

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Regulatory networks involving transcription factors and core cell cycle regulators are expected to play crucial roles in plant growth and development. In this report, we describe the identification of two groups of co-transcribed core cell cycle regulators and transcription factors via a two-step in silico screening. The core cell cycle regulators include TARDY ASYNCHRONOUS MEIOSIS (CYCA1;2), CYCB1;1, CYCB2;1, CDKB1;2, and CDKB2;2 while the transcription factors include CURLY LEAF, AINTEGUMENTA, a MYB protein, two Forkhead-associated domain proteins, and a SCARECROW family protein. Promoter analysis revealed a potential web of cross- and self-regulations among the identified proteins. Because one criterion for screening for these genes is that they are predominantly transcribed in young organs but not in mature organs, these genes are likely to be particularly involved in Arabidopsis organ growth.

  19. Leucaena leucocephala and adjacent native limestone forest habitats contrast in soil properties on Tinian Island.

    Science.gov (United States)

    Marler, Thomas E; Dongol, Nirmala; Cruz, Gil N

    2016-01-01

    An ex situ germplasm collection of the endangered Cycas micronesica was established in a transition zone between biodiverse native forest and mature stands of the invasive species Leucaena leucocephala. Soil chemical properties were determined for the 2 tree cover types to inform management decisions. Total carbon, total nitrogen, calcium, and net ammonification were greater in native forest cover than in L. leucocephala patches. Net nitrification and net mineralization were greater under L. leucocephala cover. Trace metals also differed between the 2 forest cover types, with chromium, cobalt, and nickel accumulating to greater concentration under L. leucocephala cover and zinc accumulating to greater concentration under native forest cover. The results indicated that L. leucocephala cover generated substantial changes in soil chemical properties when compared with native forest tree cover, illuminating one means by which understory vegetation may be affected by changes in invasive tree cover.

  20. Development of Randomly Amplified Polymorphic DNA Based SCAR Marker for Identification of Ipomoea mauritiana Jacq (Convolvulaceae

    Directory of Open Access Journals (Sweden)

    Kambiranda Devaiah

    2011-01-01

    Full Text Available Vidari is an Ayurvedic herbal drug used as aphrodisiac, galactagogue and is also used in the preparation of Chyavanaprash. Tubers of Ipomoea mauritiana Jacq. (Convolvulaceae, Pueraria tuberosa (Roxb. ex Willd. DC (Fabaceae, Adenia hondala (Gaertn. de Wilde (Passifloraceae and pith of Cycas circinalis L. (Cycadaceae are all traded in the name of Vidari, creating issues of botanical authenticity of the Ayurvedic raw drug. DNA-based markers have been developed to distinguish I. mauritiana from the other Vidari candidates. A putative 600-bp polymorphic sequence, specific to I. mauritiana was identified using randomly amplified polymorphic DNA (RAPD technique. Furthermore, sequence characterized amplified region (SCAR primers (IM1F and IM1R were designed from the unique RAPD amplicon. The SCAR primers produced a specific 323-bp amplicon in authentic I. mauritiana and not in the allied species.

  1. A database on endemic plants at Tirumala hills in India

    Science.gov (United States)

    Latheef, Shaik Abdul; Prasad, Beerkam; Bavaji, Middi; Subramanyam, Gangapatnam

    2008-01-01

    Medicinal plants play an important role in health care. The use of medicinal plants for treatment is growing in view of cost and non-compliance of modern medicine as in case of non-communicable diseases. Plants such as Boswellia, ovalifoliolata, Cycas beddomei, Pimpinella tirupatiensis, Pterocarpus santalinus, Shorea thumbuggaia, Syzygium alternifolium, Terminalia pallida are endemic to Tirumala hills of seshachalam range falling under the Eastern Ghats of India. These plants species have medicinal properties such as anti-tumorogenic, anti-microbial, purgative, hypoglycemic, abortificient, analgesic, anti-septic, anti-pyretic and anti-inflammatory. We created a database named DEPTH in an attempt to communicate data of these plants to the scientific community. DEPTH contains data on scientific name, vernacular name, family name, morphological description, economic importance, known medicinal compounds and medicinal importance. Availability http://svimstpt.ap.nic.in/MedicinalPlants/mainpage.htm PMID:18317578

  2. A multilevel analysis of fruit growth of two tomato cultivars in response to fruit temperature.

    Science.gov (United States)

    Okello, Robert C O; de Visser, Pieter H B; Heuvelink, Ep; Lammers, Michiel; de Maagd, Ruud A; Struik, Paul C; Marcelis, Leo F M

    2015-03-01

    Fruit phenotype is a resultant of inherent genetic potential in interaction with impact of environment experienced during crop and fruit growth. The aim of this study was to analyze the genetic and physiological basis for the difference in fruit size between a small ('Brioso') and intermediate ('Cappricia') sized tomato cultivar exposed to different fruit temperatures. It was hypothesized that fruit heating enhances expression of cell cycle and expansion genes, rates of carbon import, cell division and expansion, and shortens growth duration, whereas increase in cell number intensifies competition for assimilates among cells. Unlike previous studies in which whole-plant and fruit responses cannot be separated, we investigated the temperature response by varying fruit temperature using climate-controlled cuvettes, while keeping plant temperature the same. Fruit phenotype was assessed at different levels of aggregation (whole fruit, cell and gene) between anthesis and breaker stage. We showed that: (1) final fruit fresh weight was larger in 'Cappricia' owing to more and larger pericarp cells, (2) heated fruits were smaller because their mesocarp cells were smaller than those of control fruits and (3) no significant differences in pericarp carbohydrate concentration were detected between heated and control fruits nor between cultivars at breaker stage. At the gene level, expression of cell division promoters (CDKB2, CycA1 and E2Fe-like) was higher while that of the inhibitory fw2.2 was lower in 'Cappricia'. Fruit heating increased expression of fw2.2 and three cell division promoters (CDKB1, CDKB2 and CycA1). Expression of cell expansion genes did not corroborate cell size observations.

  3. Stomatal Blue Light Response Is Present in Early Vascular Plants.

    Science.gov (United States)

    Doi, Michio; Kitagawa, Yuki; Shimazaki, Ken-ichiro

    2015-10-01

    Light is a major environmental factor required for stomatal opening. Blue light (BL) induces stomatal opening in higher plants as a signal under the photosynthetic active radiation. The stomatal BL response is not present in the fern species of Polypodiopsida. The acquisition of a stomatal BL response might provide competitive advantages in both the uptake of CO2 and prevention of water loss with the ability to rapidly open and close stomata. We surveyed the stomatal opening in response to strong red light (RL) and weak BL under the RL with gas exchange technique in a diverse selection of plant species from euphyllophytes, including spermatophytes and monilophytes, to lycophytes. We showed the presence of RL-induced stomatal opening in most of these species and found that the BL responses operated in all euphyllophytes except Polypodiopsida. We also confirmed that the stomatal opening in lycophytes, the early vascular plants, is driven by plasma membrane proton-translocating adenosine triphosphatase and K(+) accumulation in guard cells, which is the same mechanism operating in stomata of angiosperms. These results suggest that the early vascular plants respond to both RL and BL and actively regulate stomatal aperture. We also found three plant species that absolutely require BL for both stomatal opening and photosynthetic CO2 fixation, including a gymnosperm, C. revoluta, and the ferns Equisetum hyemale and Psilotum nudum.

  4. Stomatal Blue Light Response Is Present in Early Vascular Plants1[OPEN

    Science.gov (United States)

    Doi, Michio; Kitagawa, Yuki; Shimazaki, Ken-ichiro

    2015-01-01

    Light is a major environmental factor required for stomatal opening. Blue light (BL) induces stomatal opening in higher plants as a signal under the photosynthetic active radiation. The stomatal BL response is not present in the fern species of Polypodiopsida. The acquisition of a stomatal BL response might provide competitive advantages in both the uptake of CO2 and prevention of water loss with the ability to rapidly open and close stomata. We surveyed the stomatal opening in response to strong red light (RL) and weak BL under the RL with gas exchange technique in a diverse selection of plant species from euphyllophytes, including spermatophytes and monilophytes, to lycophytes. We showed the presence of RL-induced stomatal opening in most of these species and found that the BL responses operated in all euphyllophytes except Polypodiopsida. We also confirmed that the stomatal opening in lycophytes, the early vascular plants, is driven by plasma membrane proton-translocating adenosine triphosphatase and K+ accumulation in guard cells, which is the same mechanism operating in stomata of angiosperms. These results suggest that the early vascular plants respond to both RL and BL and actively regulate stomatal aperture. We also found three plant species that absolutely require BL for both stomatal opening and photosynthetic CO2 fixation, including a gymnosperm, C. revoluta, and the ferns Equisetum hyemale and Psilotum nudum. PMID:26307440

  5. Negative feedback regulation of auxin signaling by ATHB8/ACL5-BUD2 transcription module.

    Science.gov (United States)

    Baima, Simona; Forte, Valentina; Possenti, Marco; Peñalosa, Andrés; Leoni, Guido; Salvi, Sergio; Felici, Barbara; Ruberti, Ida; Morelli, Giorgio

    2014-06-01

    The role of auxin as main regulator of vascular differentiation is well established, and a direct correlation between the rate of xylem differentiation and the amount of auxin reaching the (pro)cambial cells has been proposed. It has been suggested that thermospermine produced by ACAULIS5 (ACL5) and bushy and dwarf2 (BUD2) is one of the factors downstream to auxin contributing to the regulation of this process in Arabidopsis. Here, we provide an in-depth characterization of the mechanism through which ACL5 modulates xylem differentiation. We show that an increased level of ACL5 slows down xylem differentiation by negatively affecting the expression of homeodomain-leucine zipper (HD-ZIP) III and key auxin signaling genes. This mechanism involves the positive regulation of thermospermine biosynthesis by the HD-ZIP III protein Arabidopsis thaliana homeobox8 tightly controlling the expression of ACL5 and BUD2. In addition, we show that the HD-ZIP III protein REVOLUTA contributes to the increased leaf vascularization and long hypocotyl phenotype of acl5 likely by a direct regulation of auxin signaling genes such as like auxin resistant2 (LAX2) and LAX3. We propose that proper formation and differentiation of xylem depend on a balance between positive and negative feedback loops operating through HD-ZIP III genes.

  6. Genome-wide identification of KANADI1 target genes.

    Directory of Open Access Journals (Sweden)

    Paz Merelo

    Full Text Available Plant organ development and polarity establishment is mediated by the action of several transcription factors. Among these, the KANADI (KAN subclade of the GARP protein family plays important roles in polarity-associated processes during embryo, shoot and root patterning. In this study, we have identified a set of potential direct target genes of KAN1 through a combination of chromatin immunoprecipitation/DNA sequencing (ChIP-Seq and genome-wide transcriptional profiling using tiling arrays. Target genes are over-represented for genes involved in the regulation of organ development as well as in the response to auxin. KAN1 affects directly the expression of several genes previously shown to be important in the establishment of polarity during lateral organ and vascular tissue development. We also show that KAN1 controls through its target genes auxin effects on organ development at different levels: transport and its regulation, and signaling. In addition, KAN1 regulates genes involved in the response to abscisic acid, jasmonic acid, brassinosteroids, ethylene, cytokinins and gibberellins. The role of KAN1 in organ polarity is antagonized by HD-ZIPIII transcription factors, including REVOLUTA (REV. A comparison of their target genes reveals that the REV/KAN1 module acts in organ patterning through opposite regulation of shared targets. Evidence of mutual repression between closely related family members is also shown.

  7. Isolation and quantification of a new tuliposide (tuliposide D) by HPLC in Alstroemeria.

    Science.gov (United States)

    Christensen, L P; Kristiansen, K

    1995-09-01

    From aqueous extracts of flowers, stems and leaves of 1 Brazilian and 15 Chilean Alstroemeria species, the content of a new tuliposide, named tuliposide D, was determined by isocratic reversed-phase high-performance liquid chromatography (RP-HPLC), using distilled water:methanol (80:20) as mobile phase. The compound was detected by a UV-detector at 208 nm. Tuliposide D was found in almost all Alstroemeria species investigated, although in very different amounts. Most species contained relatively small amounts of tuliposide D, especially in the leaves. However, A. hookeri ssp. cummingiana, A. presliana ssp. presliana, A. pseudospathulata and A. revoluta contained large amounts of tuliposide D in all plant parts. Tuliposide D was identified as 1,6-di-(4-hydroxy-2-methylenebutanoate)-beta-D-glucopyranose by UV, FAB-MS, 1H- and 13C-NMR. The content of the allergens 6-tuliposide A and tulipalin A was also determined by RP-HPLC and the possibility that tuliposide D is a further causative agent of allergic contact dermatitis in Alstroemeria is discussed.

  8. ZLL/AGO10 maintains shoot meristem stem cells during Arabidopsis embryogenesis by down-regulating ARF2-mediated auxin response.

    Science.gov (United States)

    Roodbarkelari, Farshad; Du, Fei; Truernit, Elisabeth; Laux, Thomas

    2015-09-10

    The shoot meristem gives rise to new organs throughout a plant's life by the activity of pluripotent stem cells in the meristem center. Organ initiation at the periphery of the shoot meristem is triggered by the accumulation of the phytohormone auxin at the initiation site. Loss-of-function mutants of the ZWILLE/ARGONAUTE10/PINHEAD (ZLL/AGO10/PNH) gene terminate shoot meristem stem cells late in embryogenesis and can form a leaf or a leaf-like structure instead, indicating that AGO10 activity is required to maintain shoot meristem stem cells undifferentiated. Here, we addressed whether stem cell maintenance by AGO10 involves regulation of auxin. We found that in zll-1 mutants, auxin accumulation and expression of the response reporter DR5:GFP are elevated, and transcription of the Auxin Response Factor 2 (ARF2) gene is upregulated. Downregulation of ARF2 significantly restores stem cells in zll-1 mutants, whereas increased expression of ARF2 enhances differentiation of stem cells in zll-1 mutants. We further found that upregulation of the AGO10 effector gene REVOLUTA restores ARF2 expression and stem cell maintenance in zll-1 embryos. Our results indicate that maintenance of shoot meristem stem cells by AGO10 involves negative regulation of auxin signaling and, via REV-mediated downregulation of ARF2 expression, auxin response.

  9. Studies on the Characteristics of Photosynthesis and Transpiration of Six Tropical Garden Plants in the Greenhouse Environment%6种热带园林植物在温室环境下的光合及蒸腾特性的研究

    Institute of Scientific and Technical Information of China (English)

    幸宏伟; 代雪

    2012-01-01

    为研究热带园林植物在温室环境下的光合及蒸腾作用,对重庆南山植物园热带温室环境条件下,苏铁蕨、象腿芭蕉、酒瓶椰子、琴叶榕、人心果和海南龙血树6种植物的光合效率、蒸腾效率及水分利用效率进行了测定,结果表明:(1)几种热带园林植物都有明显的光合速率日变化,部分树种存在因气孔导度下降而引起的"午休"现象.(2)植物的光合速率大小与植物叶绿素含量无直接相关.(3)6树种光合速率从大到小依次为:人心果,龙血树,象腿芭蕉,酒瓶椰子,苏铁蕨,琴叶榕;蒸腾速率从大到小依次为:龙血树,琴叶榕,象腿芭蕉,苏铁蕨,人心果,酒瓶椰子;水分利用效率从高到低依次为:人心果,象腿芭蕉,龙血树,琴叶榕,酒瓶椰子,苏铁蕨.%To study the photosynthesis and transpiration of tropical garden plants living in the greenhouse which is different from their original habitats, we analyzed the characteristics of photosynthesis and transpiration of cycads fern (Brainea insignis), leg-shaped banana (Ensete glaucum (Roxb.) Cheesman), bottle palm (Mascarena lagenicaulis ) , fiddle-leaved fig (Ficus pandurata ) , Jackfruit (Achras sapota ) and Hainan dragon blood tree (Dracaena carnbodianajui Pierre ex Gagnep) growing under the environ- mental conditions in Chongqing Nanshan Botanical Garden's greenhouses. An obvious diurnal variation was observed in the photosynthetic rate of all the species studied, and a phenomenon of "nap" occurred in some species owing to the decline in their stomatal conductance. Photosynthesis rate of the plants had no direct relevance to their chlorophyll content. Their photosynthetic rate appeared in the order of Jackfruit Hainan dragon blood tree 〉 leg-shaped banana 〉 bottle palm 〉 cycads fern 〉 fiddle-leaved fig, their transpiration rate was in the order of Hainan dragon blood tree〉 fiddle-leaved fig 〉 leg

  10. Beta-methylamino-L-alanine analysis by liquid chromatography tandem mass spectrometry with iTRAQ as the derivative.

    Science.gov (United States)

    Kushnir, Mark M; Bergquist, Jonas

    2009-01-01

    Amino acid BMMA is produced by cyanobacteria and has been linked to the development of neurodegenerative diseases. We developed a method for quantitative analysis of BMAA in biological samples and plant extracts. The method is utilizing iTRAQ and LC-MS/MS detection using multiple reaction monitoring mode. The method uses 50 microL of sample and has a limit of quantitation of 300 ng mL(-1), within-run run imprecision below 1%. Using this method we analyzed human serum samples, human cerebrospinal fluid samples and extract of the cycad seed. No BMAA could be detected in the human samples. Content of BMAA in the seed was 50 mg kg(-1).

  11. Presence of arbuscular mycorrhizal fungi in South Florida native plants.

    Science.gov (United States)

    Fisher, Jack B; Jayachandran, K

    2005-11-01

    The roots of 27 species of South Florida plants in 15 families (including one cycad, six palms, one Smilax, and 19 dicotyledons) native to pine rockland and tropical hardwood hammock communities were examined for arbuscular mycorrhizal fungi (AMF). These plants grow in the biologically diverse but endangered Greater Everglades habitat. Roots from field-grown and potted plants were cleared and stained. All 27 species had AMF and include 14 species having an endangered or threatened status. The Paris-type colonization occurred in two species in the families Annonaceae and Smilacaceae. The Arum-type occurred in 22 species in the families Anacardiaceae, Arecaceae (Palmae), Boraginaceae, Cactaceae (questionable), Euphorbiaceae, Fabaceae, Lauraceae, Melastomataceae, Polygalaceae, Rubiaceae, Simaroubaceae, Ulmaceae, and Zamiaceae. Three species in the families Fabaceae, Lauraceae, and Simaroubaceae had a mix of Paris- and Arum-types. The results have implications for the restoration of these endangered plant communities in the Everglades.

  12. Evolution of Xylan Substitution Patterns in Gymnosperms and Angiosperms: Implications for Xylan Interaction with Cellulose.

    Science.gov (United States)

    Busse-Wicher, Marta; Li, An; Silveira, Rodrigo L; Pereira, Caroline S; Tryfona, Theodora; Gomes, Thiago C F; Skaf, Munir S; Dupree, Paul

    2016-08-01

    The interaction between cellulose and xylan is important for the load-bearing secondary cell wall of flowering plants. Based on the precise, evenly spaced pattern of acetyl and glucuronosyl (MeGlcA) xylan substitutions in eudicots, we recently proposed that an unsubstituted face of xylan in a 2-fold helical screw can hydrogen bond to the hydrophilic surfaces of cellulose microfibrils. In gymnosperm cell walls, any role for xylan is unclear, and glucomannan is thought to be the important cellulose-binding polysaccharide. Here, we analyzed xylan from the secondary cell walls of the four gymnosperm lineages (Conifer, Gingko, Cycad, and Gnetophyta). Conifer, Gingko, and Cycad xylan lacks acetylation but is modified by arabinose and MeGlcA. Interestingly, the arabinosyl substitutions are located two xylosyl residues from MeGlcA, which is itself placed precisely on every sixth xylosyl residue. Notably, the Gnetophyta xylan is more akin to early-branching angiosperms and eudicot xylan, lacking arabinose but possessing acetylation on alternate xylosyl residues. All these precise substitution patterns are compatible with gymnosperm xylan binding to hydrophilic surfaces of cellulose. Molecular dynamics simulations support the stable binding of 2-fold screw conifer xylan to the hydrophilic face of cellulose microfibrils. Moreover, the binding of multiple xylan chains to adjacent planes of the cellulose fibril stabilizes the interaction further. Our results show that the type of xylan substitution varies, but an even pattern of xylan substitution is maintained among vascular plants. This suggests that 2-fold screw xylan binds hydrophilic faces of cellulose in eudicots, early-branching angiosperm, and gymnosperm cell walls.

  13. False Blister Beetles and the Expansion of Gymnosperm-Insect Pollination Modes before Angiosperm Dominance.

    Science.gov (United States)

    Peris, David; Pérez-de la Fuente, Ricardo; Peñalver, Enrique; Delclòs, Xavier; Barrón, Eduardo; Labandeira, Conrad C

    2017-02-26

    During the mid-Cretaceous, angiosperms diversified from several nondiverse lineages to their current global domination [1], replacing earlier gymnosperm lineages [2]. Several hypotheses explain this extensive radiation [3], one of which involves proliferation of insect pollinator associations in the transition from gymnosperm to angiosperm dominance. However, most evidence supports gymnosperm-insect pollinator associations, buttressed by direct evidence of pollen on insect bodies, currently established for four groups: Thysanoptera (thrips), Neuroptera (lacewings), Diptera (flies), and now Coleoptera (beetles). Each group represents a distinctive pollination mode linked to a unique mouthpart type and feeding guild [4-9]. Extensive indirect evidence, based on specialized head and mouthpart morphology, is present for one of these pollinator types, the long-proboscid pollination mode [10], representing minimally ten family-level lineages of Neuroptera, Mecoptera (scorpionflies), and Diptera [8, 10, 11]. A recurring feature uniting these pollinator modes is host associations with ginkgoalean, cycad, conifer, and bennettitalean gymnosperms. Pollinator lineages bearing these pollination modes were categorized into four evolutionary cohorts during the 35-million-year-long angiosperm radiation, each defined by its host-plant associations (gymnosperm or angiosperm) and evolutionary pattern (extinction, continuation, or origination) during this interval [12]. Here, we provide the first direct evidence for one cohort, exemplified by the beetle Darwinylus marcosi, family Oedemeridae (false blister beetles), that had an earlier gymnosperm (most likely cycad) host association, later transitioning onto angiosperms [13]. This association constitutes one of four patterns explaining the plateau of family-level plant lineages generally and pollinating insects specifically during the mid-Cretaceous angiosperm radiation [12].

  14. Evolution of Xylan Substitution Patterns in Gymnosperms and Angiosperms: Implications for Xylan Interaction with Cellulose1[OPEN

    Science.gov (United States)

    Li, An; Gomes, Thiago C.F.

    2016-01-01

    The interaction between cellulose and xylan is important for the load-bearing secondary cell wall of flowering plants. Based on the precise, evenly spaced pattern of acetyl and glucuronosyl (MeGlcA) xylan substitutions in eudicots, we recently proposed that an unsubstituted face of xylan in a 2-fold helical screw can hydrogen bond to the hydrophilic surfaces of cellulose microfibrils. In gymnosperm cell walls, any role for xylan is unclear, and glucomannan is thought to be the important cellulose-binding polysaccharide. Here, we analyzed xylan from the secondary cell walls of the four gymnosperm lineages (Conifer, Gingko, Cycad, and Gnetophyta). Conifer, Gingko, and Cycad xylan lacks acetylation but is modified by arabinose and MeGlcA. Interestingly, the arabinosyl substitutions are located two xylosyl residues from MeGlcA, which is itself placed precisely on every sixth xylosyl residue. Notably, the Gnetophyta xylan is more akin to early-branching angiosperms and eudicot xylan, lacking arabinose but possessing acetylation on alternate xylosyl residues. All these precise substitution patterns are compatible with gymnosperm xylan binding to hydrophilic surfaces of cellulose. Molecular dynamics simulations support the stable binding of 2-fold screw conifer xylan to the hydrophilic face of cellulose microfibrils. Moreover, the binding of multiple xylan chains to adjacent planes of the cellulose fibril stabilizes the interaction further. Our results show that the type of xylan substitution varies, but an even pattern of xylan substitution is maintained among vascular plants. This suggests that 2-fold screw xylan binds hydrophilic faces of cellulose in eudicots, early-branching angiosperm, and gymnosperm cell walls. PMID:27325663

  15. Climate Ecology Resources of Cycod Nature Reserve in Wangmo of Guizhou%贵州望谟苏铁自然保护区气候生态资源

    Institute of Scientific and Technical Information of China (English)

    穆彪; 胡明亮; 张莉; 毛亚昆

    2011-01-01

    Results from investigating the climate ecology resources of the Cycad Nature Reserve in Wangmo county of Guizhou showed that the annual sunshine duration, annual percentage of sunshine,annual amount of solar radiation, annual mean temperature,≥10℃ continued days, ≥10℃ accumulated temperature and annual precipitation was 1 362.3~1 526. Oh, 31%~34%, 3942. 5~4222.3MJ/m2, 15. 1~20.5℃, 284~313d, 6076. 1~6859. 8℃ and 1063. 7~1391.9mm respectively. This area is the wild Cycad and orchid's natural microhabitat with high natural landscape tour value.%为了解贵州望谟苏铁自然保护区的气候生态资源,对贵州望谟苏铁自然保护区气候生态资源进行了调查分析.结果表明,该区年日照数为1 362.3~1 526.0 h,年日照率为31%~34%,年太阳总辐射为3 942.5~4 222.3 MJ/m2;年均温为15.1~20.5℃,≥10℃的持续日数达287~313 d,≥10℃的积温为6 076.1~6 859.8℃;年降雨量为1 063.7~1 391.9 mm.该地区是野生贵州苏铁和兰花的天然小生境,同时具有较高的自然景观游览价值.

  16. Diversity of Protozoa Communities on Cryptogamic Vegetation from Mining Area%矿区隐花植被附生原生动物群落的多样性

    Institute of Scientific and Technical Information of China (English)

    蒋亚辉; 王智慧

    2012-01-01

    为了给矿区的环境污染监测提供参考,对贵州省黔西南州王家湾金矿采集区的拟阔叶小石藓(Weisia platyphylloides Card)、舟形藻(Navicula Bory)和蕨的叶、茎、表土和根际土以及矿渣裸土样中的原生动物种类进行了研究.结果表明:矿区隐花植被附生和土壤中原生动物群落物种数为24种,常见种有洁净眼虫(Euglena clara)、透明螺足虫(Cochliopodium bilimbosum)、旋转单镰虫(Drepanomonas revoluta)、葡萄异鞭藻(Anisonema acinus)和大口表壳虫(Arcella megastoma);拟阔叶小石藓附生原生动物种类数为9种,蕨的叶附生原生动物为7种,蕨茎附生的有6种,根际土中附生原生动物有5种,舟形藻附生原生动物种类数为3种,蕨的表土和矿渣裸土中未发现原生动物.肾形虫属是矿区的优势属;不同隐花植被和同种隐花植被不同部位的附生原生动物群落相似性均为极不相似,群落组成有较大差异.%In order to provide a reference for the monitoring of environmental pollution of mining area, protozoan communities on Weisia platyphylloides , Navicula, fern leaves, fern stems, fern top soil, fern rhizosphere soil and slag bare soil from W lateritic gold mining area in Qianxinan County were studied. The results showed that 24 species protozoa were identified in cryptogamic vegetation and soil, in which Euglena clara, Cochliopodium bilimbosum , Drepanomonas revoluta , Anisonema acinus, Arcella megastoma were common species, nine species were identified in W. platyphylloides, seven species were identified in fern leaves, six species were identified in fern stems, five species were identified in fern rhizosphere soil, three species were identified in Navicula. But protozoa were not found in top soil of fern and in slag bare soil. Colpoda was the dominant genus in Wangjiawan lateritic gold mining area. Community similarity coefficients showed that protozoan community on different cryptogamic vegetation and

  17. Systematic studies in Turnera (Turneraceae. IV. Series Leiocarpae, Conciliatae and Sessilifoliae ESTUDIOS SISTEMÁTICOS EN TURNERA (TURNERACEAE. IV. SERIES LEIOCARPAE, CONCILIATAE Y SESSILIFOLIAE

    Directory of Open Access Journals (Sweden)

    María Mercedes Arbo

    2010-07-01

    Full Text Available In this paper the revision of the series Leiocarpae Urb. is presented, and Turnera callosa Urb. is chosen as lectotype. This series has a distribution similar to that of the genus Turnera in America, most species living in the Chaquean biogeographical region. It has 55 species, the following taxa being new: T. angelicae, T. dasytricha var. crinita, T. diamantinae, T. emendata, T. fissifolia, T. glabrata, T. gouveiana, T. humilis, T. iterata, T. jobertii, T. luetzelburgii var. dubia, T. melochioides var. rugosa, T. paradoxa, T. patens, T. rosulata, T. vallsii, T. venezuelana and T. vicaria. Two new series are also proposed, Conciliatae Arbo for T. rubrobracteata Arbo, a species with an unusual combination of characters, which does not fit in any other series, and Sessilifoliae Arbo, including T. dichotomaand T. revoluta which were excluded from Series Capitatae; the comparative analysis with the members of Leiocarpae has demonstrated that they neither belong to the last series. Keys to identify the different series of the genus and keys for the species of each series treated are provided, as well as morphological descriptions, illustrations and distribution maps

    En este trabajo se presenta la revisión de la serie Leiocarpae Urb., seleccionándose a Turnera
    callosa Urb. como lectotypus. Esta serie tiene una distribución similar a la del género Turnera
    en América; presenta 55 especies, la mayoría de las cuales vive en la región biogeográfica
    Chaqueña. Son nuevos los siguientes taxones: T. angelicae, T. dasytricha var. crinita,
    T. diamantinae, T. emendata, T. fissifolia, T. glabrata, T. gouveiana, T. humilis, T. iterata,
    T. jobertii, T

  18. 酵母CYC1启动子TATA框对ERE调控的报告基因的影响%The Effects of TATA-box in CYC1 Promoter on the Reporter Gene Regulated by ERE in the Recombinant Yeast Cell

    Institute of Scientific and Technical Information of China (English)

    谭明典; 罗方妮; 葛宜枝; 李晶晶; 徐海荣; 李湘鸣

    2011-01-01

    人工合成两条雌激素效应元件(ERE) 重复的核苷酸序列,并在5′和3′端设计Hind Ⅲ and Sph Ⅰ黏性末端.将两条互补的ERE溶液加热至95℃,然后冷却至室温使其形成双股DNA,将双股ERE插入到pERE-CYC-yEGFP载体的细胞色素C(CYC1)启动子相应的酶切位点,生成pERE-CYCα-yEGFP载体.pERE-CYC-yEGFP和pERE-CYCα-yEGFP载体的不同之处是ERE位于CYC1启动子的位置,前者ERE下游的CYC1启动子含有α和β-TATA框,而后只含有α-TATA框.将两者分别转化于可表达人雌激素受体的酵母细胞,构建成两种受雌激素调控的重组酵母细胞.将该重组酵母细胞经6种不同的雌激素化合物作用4 h,发现重组pERE-CYCα-yEGFP的酵母细胞的绿色荧光蛋白(GFP)表达量与受试物间剂量效应关系较差,而含有pERE-CYC-yEGFP载体重组酵母细胞,与受试物具有明显的剂量效应关系.因此,在用于快速、高通量筛选雌激素类化合物生物评价中,其CYC1基本启动子中的α和β-TATA框是必须的.%The complementary oligonucleotides, each with two consensus estrogen response element (ERE)-sequences and 5'-Hind HI and 3'-Sph I sticky ends were artificially synthesized. A solution with both the complementary DNA sequences was heated to 95^0 and cooled down to room temperature to form double strand DNA (dsD-NA). The set was cloned into the corresponding sites of CYC1 promoter of the pERE-CYC-yEGFP to yield pERE-CYCa-yEGFP vector. The two different reporter vectors, pERE-CYC-yEGFP and pERE-CYCa-yEGFP, the 2ERE, were placed in the CYC1 promoter. The former promoter downstream ERE contains a and 0-TATA boxes and the latter has only a -TATA box. The two different reporter vectors were transformed into the yeast cells that express human estrogen receptor o (Era). Incubation of the recombinant yeasts with the six estrogenic compounds for 4 hours showed that the recombinant cell containing pERE-CYCa-yEGFP would give very poor dose-response curves

  19. Characterization of microRNAs expressed during secondary wall biosynthesis in Acacia mangium.

    Science.gov (United States)

    Ong, Seong Siang; Wickneswari, Ratnam

    2012-01-01

    MicroRNAs (miRNAs) play critical regulatory roles by acting as sequence specific guide during secondary wall formation in woody and non-woody species. Although thousands of plant miRNAs have been sequenced, there is no comprehensive view of miRNA mediated gene regulatory network to provide profound biological insights into the regulation of xylem development. Herein, we report the involvement of six highly conserved amg-miRNA families (amg-miR166, amg-miR172, amg-miR168, amg-miR159, amg-miR394, and amg-miR156) as the potential regulatory sequences of secondary cell wall biosynthesis. Within this highly conserved amg-miRNA family, only amg-miR166 exhibited strong differences in expression between phloem and xylem tissue. The functional characterization of amg-miR166 targets in various tissues revealed three groups of HD-ZIP III: ATHB8, ATHB15, and REVOLUTA which play pivotal roles in xylem development. Although these three groups vary in their functions, -psRNA target analysis indicated that miRNA target sequences of the nine different members of HD-ZIP III are always conserved. We found that precursor structures of amg-miR166 undergo exhaustive sequence variation even within members of the same family. Gene expression analysis showed three key lignin pathway genes: C4H, CAD, and CCoAOMT were upregulated in compression wood where a cascade of miRNAs was downregulated. This study offers a comprehensive analysis on the involvement of highly conserved miRNAs implicated in the secondary wall formation of woody plants.

  20. 中国石斛属一新种%A new species of Dendrobium (Orchidaceae) from China

    Institute of Scientific and Technical Information of China (English)

    金效华; 张玉武; 肖丽萍

    2001-01-01

    @@Dendrobium fanjingshanense Z. H. Tsi ex X. H. Jin et Y. W. Zhang, sp. nov. Fig. 1 Habitu D. wilsonii Rolfe simile, a quo tepalis revolutis fulvis, lobo labelli intermedii infra medium macula una flabellata purpurea ornato. Epiphyticum; caulis teres, 20~40 cm altus, 2~3 mm crassus, caespitosus, superne 5~6-foliatus, internodiis 1~1.5 cm longis. Folia oblongo-lanceolata, subcoriacea, 2~5 cm longa, 5~15 mm lata, apice obtusa et plus minusve hamata, basi vaginis tubulatis membranaceis obtecta. Inflorescentiae e lateribus partium superarum caulium annotinorum defoliatorum nascentes, versus apicem caulis laterales, 1~2-florae; pedunculi 2~3 mm longi, ca. 1 mm crassi, basi vaginis 3~4 membranaceis 3~4 mm longis instructi; bracteae ovato-triangulatae, 3~5 mm longae, apice acutae, macula atro-fusca ornatae. Flores patentes; pedicelli cum ovario ca. 2~3 cm longi; tepala revoluta, fulva, apice obtusa; sepalum intermedium oblongum 2 cm longum, medio 6~7 mm latum, apice fere obtusum; sepala lateralia paulo oblique ovato-lanceolata, sepalo intermedio aequilonga sed medio paulo angustiora, apice obtusa, basi cum pede columnae mentum obconoideum ca. 8 mm longum 6 mm latum apice obtusum formantia; petala subelliptica, ca. 2 cm longa, medio 6 mm lata, apice subobtusa; labellum fulvum, basi purpureum et dense velutinum, obscure trilobatum, lobis lateralibus semiorbiculatis erectis, basi (inter lobos laterales) callo uno purpureo praeditis, lobo intermedio ovato, ca. 1 cm longo, 7 mm lato, apice subacuto et recurvo, supra medio carinato, glabro; columna alba, ca. 3 mm longa, basi in pedem ca. 9 mm longum producta, pede medio purpurato, glabro; operculum antherae album, ambitu rhombicum, glabrum; pollinia 4.

  1. TIR-NBS-LRR genes are rare in monocots: evidence from diverse monocot orders

    Directory of Open Access Journals (Sweden)

    Tarr D Ellen K

    2009-09-01

    Full Text Available Abstract Background Plant resistance (R gene products recognize pathogen effector molecules. Many R genes code for proteins containing nucleotide binding site (NBS and C-terminal leucine-rich repeat (LRR domains. NBS-LRR proteins can be divided into two groups, TIR-NBS-LRR and non-TIR-NBS-LRR, based on the structure of the N-terminal domain. Although both classes are clearly present in gymnosperms and eudicots, only non-TIR sequences have been found consistently in monocots. Since most studies in monocots have been limited to agriculturally important grasses, it is difficult to draw conclusions. The purpose of our study was to look for evidence of these sequences in additional monocot orders. Findings Using degenerate PCR, we amplified NBS sequences from four monocot species (C. blanda, D. marginata, S. trifasciata, and Spathiphyllum sp., a gymnosperm (C. revoluta and a eudicot (C. canephora. We successfully amplified TIR-NBS-LRR sequences from dicot and gymnosperm DNA, but not from monocot DNA. Using databases, we obtained NBS sequences from additional monocots, magnoliids and basal angiosperms. TIR-type sequences were not present in monocot or magnoliid sequences, but were present in the basal angiosperms. Phylogenetic analysis supported a single TIR clade and multiple non-TIR clades. Conclusion We were unable to find monocot TIR-NBS-LRR sequences by PCR amplification or database searches. In contrast to previous studies, our results represent five monocot orders (Poales, Zingiberales, Arecales, Asparagales, and Alismatales. Our results establish the presence of TIR-NBS-LRR sequences in basal angiosperms and suggest that although these sequences were present in early land plants, they have been reduced significantly in monocots and magnoliids.

  2. Estudo da regeneração natural de espécies arbóreas em fragmento de Floresta Ombrófila Densa, Mata das Galinhas, no município de Catende, zona da mata sul de Pernambuco

    Directory of Open Access Journals (Sweden)

    Wegliane Campelo da Silva

    2007-01-01

    Full Text Available The study was developed in the fragment situated in the Catende is – PE city (Mata das Galinhas – 8º69’06”S e 35º69’08” W, in mesoregion of the pernambucana forest, more necessarily in the humid forest is microregion, at 142 km of the capital. The area is vegetacion is Humid Forest. The relief varies wavy to very wavy, with 199 m altitude. The soil is classified as red latisols dystrophic and red nitosols associated to latisols. The present work aims to study and evaluated the total natural regeneration of arboreal species in the forest fragment and to verify the diversity and structure of the species in the same one. For estimate the natural regeneration, were made systematically 16 subunits (samples with 5 x 5 m. These subunits were inserted in the middle samples (10 x 25 m before used to evaluate the community arboreal phytossociology, with 50 meters between the ones. The regeneration study (CAP 3 m. Besides, the samply sufficient and diversity were calculated. In fragment was observed 31 botanical families and 60 arboreal species inside 194 individuals. 42 had been identified in level of species, 4 in sort level, 2 in family level and 2 are not identify. Ten species obtained bigest values for total natural regeneration of the samples population (RNT and contribute with 53,78% of the total percentage, how is descript following way: Brosimum discolor Schott (9,98%, Protium heptaphyllum (Aubl. Marchand (9,19%, Eschweilera ovata (Cambess. Miers (8,01%, Thyrsodium spruceanum Benth. (7,0%, Dialium guianense (Aubl. Sandwith (5,44%, Erythroxylum squamatum Sw. (3,32%, Cupania revoluta Rolfe (3,16%, Sorocea hilarii Gaudich.

  3. Complete nucleotide sequence of the Cryptomeria japonica D. Don. chloroplast genome and comparative chloroplast genomics: diversified genomic structure of coniferous species

    Science.gov (United States)

    Hirao, Tomonori; Watanabe, Atsushi; Kurita, Manabu; Kondo, Teiji; Takata, Katsuhiko

    2008-01-01

    Background The recent determination of complete chloroplast (cp) genomic sequences of various plant species has enabled numerous comparative analyses as well as advances in plant and genome evolutionary studies. In angiosperms, the complete cp genome sequences of about 70 species have been determined, whereas those of only three gymnosperm species, Cycas taitungensis, Pinus thunbergii, and Pinus koraiensis have been established. The lack of information regarding the gene content and genomic structure of gymnosperm cp genomes may severely hamper further progress of plant and cp genome evolutionary studies. To address this need, we report here the complete nucleotide sequence of the cp genome of Cryptomeria japonica, the first in the Cupressaceae sensu lato of gymnosperms, and provide a comparative analysis of their gene content and genomic structure that illustrates the unique genomic features of gymnosperms. Results The C. japonica cp genome is 131,810 bp in length, with 112 single copy genes and two duplicated (trnI-CAU, trnQ-UUG) genes that give a total of 116 genes. Compared to other land plant cp genomes, the C. japonica cp has lost one of the relevant large inverted repeats (IRs) found in angiosperms, fern, liverwort, and gymnosperms, such as Cycas and Gingko, and additionally has completely lost its trnR-CCG, partially lost its trnT-GGU, and shows diversification of accD. The genomic structure of the C. japonica cp genome also differs significantly from those of other plant species. For example, we estimate that a minimum of 15 inversions would be required to transform the gene organization of the Pinus thunbergii cp genome into that of C. japonica. In the C. japonica cp genome, direct repeat and inverted repeat sequences are observed at the inversion and translocation endpoints, and these sequences may be associated with the genomic rearrangements. Conclusion The observed differences in genomic structure between C. japonica and other land plants, including

  4. Early Oligocene plant diversity along the Upper Rhine Graben: The fossil flora of Rauenberg, Germany

    Directory of Open Access Journals (Sweden)

    Kovar-Eder Johanna

    2016-12-01

    Full Text Available The macroflora of Rauenberg, Baden-Württemberg, Germany, is treated monographically. The plant-bearing sediments are marine, mainly well-bedded clay- to siltstones, the so-called Fischschiefer, which are part of the Bodenheim Formation. Based on nannoplankton they are dated to nannoplankton zone NP 23 (Rupelian, Lower Oligocene. The plant remains, mainly leaves and some fructifications, are preserved as compressions. The taxonomic assignment is based on gross morphology and cuticle characteristics. The flora yields marine algae and remains of the very diverse terrestrial flora. A total of 68 taxa, including three types of algae, one cycad, 12 conifers, and 49 dicots, among them 5 palms, are described. The following fossil species are described for the first time: Laurophyllum rauenbergense, Myrica obliquifolia, Distylium metzleri, ? Berchemia altorhenana, ? Ternstroemites maritiae, Trachelospermum kelleri, Oleinites altorhenana, O. rauenbergensis, Dicotylophyllum badense, D. oechsleri, D. vesiculaeferens, D. ziegleri, ? Viscophyllum hendriksiae, and Cladites vesiculaeferens. Dicotylophyllum vesiculaeferens and Cladites vesiculaeferens bear peculiar, complex cuticular structures presumably representing salt-secreting glands. Both taxa are interpreted to derive from one plant species of yet uncertain systematic affinity. The flora bears a high proportion of broad-leaved, presumably evergreen taxa, whereas the diversity of modern Arcto-Tertiary taxa (sensu Kvaček 1994 is rather low. Most abundant are Platanus neptuni, Daphnogene cinnamomifolia, and Tetraclinis salicornioides. On the family level, Lauraceae (10 species and Pinaceae (8 are most diverse, followed by Arecaceae (4-5, Cupressaceae, and Myricaceae (4 species each. Surprisingly, Fagaceae are documented solely by a single leaf of Eotrigonobalanus furcinervis f. haselbachensis, and the record of Pentaphyllaceae remains ambiguous (? Ternstroemites maritiae. Sloanea olmediaefolia is recorded

  5. 苏铁的有性繁殖

    Institute of Scientific and Technical Information of China (English)

    赖亚平

    2006-01-01

    苏铁学名Cycas reuo lute,俗称铁树,裸子植物,苏铁科。它树干挺拔,叶片呈伞形披开。树形美观,四季常绿,有很高的观赏价值,是公园、广场城镇绿地和街道绿化的首选树种。随着花园化城市的开发,住宅小区绿化标准的提高,各地对铁树的需求量与日俱增,已出现了供不应求的局面。以前苏铁繁殖全是靠树干基部孢子自然发育成球形小株,然后分种。这种繁殖方法周期长、数量少,不能满足日益增长的需求,而利用种子繁殖,每棵雌株1次就能繁殖出数百颗苏铁种来。其繁殖技术要点如下:

  6. RNA helicase Belle (DDX3) is essential for male germline stem cell maintenance and division in Drosophila.

    Science.gov (United States)

    Kotov, Alexei A; Olenkina, Oxana M; Kibanov, Mikhail V; Olenina, Ludmila V

    2016-06-01

    The present study showed that RNA helicase Belle (DDX3) was required intrinsically for mitotic progression and survival of germline stem cells (GSCs) and spermatogonial cells in the Drosophila melanogaster testes. We found that deficiency of Belle in the male germline resulted in a strong germ cell loss phenotype. Early germ cells are lost through cell death, whereas somatic hub and cyst cell populations are maintained. The observed phenotype is related to that of the human Sertoli Cell-Only Syndrome caused by the loss of DBY (DDX3) expression in the human testes and results in a complete lack of germ cells with preservation of somatic Sertoli cells. We found the hallmarks of mitotic G2 delay in early germ cells of the larval testes of bel mutants. Both mitotic cyclins, A and B, are markedly reduced in the gonads of bel mutants. Transcription levels of cycB and cycA decrease significantly in the testes of hypomorph bel mutants. Overexpression of Cyclin B in the germline partially rescues germ cell survival, mitotic progression and fertility in the bel-RNAi knockdown testes. Taken together, these results suggest that a role of Belle in GSC maintenance and regulation of early germ cell divisions is associated with the expression control of mitotic cyclins.

  7. Molecular evolution of the exon 2 of CHS genes and the possibility of its application to plant phylogenetic analysis

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The exon 2 of chalcone synthase (CHS) gene is relatively conserved during evolution.In this study,three exon 2 fragments from two species in gymnosperm (Cycas panzhihuaensis,Ginkgo biloba) and seven from four species in angiosperm (Magnolia denudata,Salix babylonica,Nymphaea tetragona,Camellia japonica) have been amplified by PCR from genomic DNA and sequenced.Together with other 73 sequences of CHS collected from EMBL database and literature,these sequences,which embrace 19 families of gymnosperm and angiosperm,have been analyzed for their phylogenetic relations by parsimony method.The result indicated that sequences from the same systematic family usually grouped together except those from Theaceae,Magnoliaceae and Nymphaeaceae.The relative rate test revealed the rate heterogeneity of CHS genes among the families.For the nucleotide substitution the sequences from Asteraceae and Solanaceae evolve faster than those from the other families analyzed while the sequences from Poaceae,Asteraceae and Solanaceae evolve faster for the nonsynonymous substitution.These results suggest that the duplication and extinction events of CHS genes are different among systematic families,therefore it seems impractical to look for orthologous sequences from CHS genes to study plant phylogeny at the family level and/or above.However,it is possible to do so below the family level.

  8. Patterns of synonymous codon usage bias in chloroplast genomes of seed plants

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Codon usage in chloroplast genome of six seed plants (Arabidopsis thaliana, Populus alba, Zea mays, Triticum aestivum,Pinus koraiensis and Cycas taitungensis) was analyzed to find general patterns of codon usage in chloroplast genomes of seed plants.The results show that chloroplast genomes of the six seed plants had similar codon usage patterns, with a strong bias towards a high representation of NNA and NNT codons. In chloroplast genomes of the six seed plants, the effective number of codons (ENC) for most genes was similar to that of the expected ENC based on the GC content at the third codon position, but several genes with low ENC values were laying below the expected curve. All of these data indicate that codon usage was dominated by a mutational bias in chloroplast genomes of seed plants and that selection appeared to be limited to a subset of genes and to only subtly affect codon us-age. Meantime, four, six, eight, nine, ten and 12 codons were defined as the optimal codons in chloroplast genomes of the six seed plants.

  9. Comparison of Soybean Transformation Efficiency and Plant Factors Affecting Transformation during the Agrobacterium Infection Process.

    Science.gov (United States)

    Jia, Yuying; Yao, Xingdong; Zhao, Mingzhe; Zhao, Qiang; Du, Yanli; Yu, Cuimei; Xie, Futi

    2015-01-01

    The susceptibility of soybean genotype to Agrobacterium infection is a key factor for the high level of genetic transformation efficiency. The objective of this study is to evaluate the plant factors related to transformation in cotyledonary nodes during the Agrobacterium infection process. This study selected three genotypes (Williams 82, Shennong 9 and Bert) with high transformation efficiency, which presented better susceptibility to Agrobacterium infection, and three low transformation efficiency genotypes (General, Liaodou 16 and Kottman), which showed a relatively weak susceptibility. Gibberellin (GA) levels and soybean GA20ox2 and CYP707A2 transcripts of high-efficiency genotypes increased and were higher than those of low-efficiency genotypes; however, the opposite performance was shown in abscisic acid (ABA). Higher zeatin riboside (ZR) content and DNA quantity, and relatively higher expression of soybean IPT5, CYCD3 and CYCA3 were obtained in high-efficiency genotypes. High-efficiency genotypes had low methyl jasmonate (MeJA) content, polyphenol oxidase (PPO) and peroxidase (POD) activity, and relatively lower expression of soybean OPR3, PPO1 and PRX71. GA and ZR were positive plant factors for Agrobacterium-mediated soybean transformation by facilitating germination and growth, and increasing the number of cells in DNA synthesis cycle, respectively; MeJA, PPO, POD and ABA were negative plant factors by inducing defence reactions and repressing germination and growth, respectively.

  10. Cellular and molecular markers in monitoring the fate of lymphoid cell culture from Penaeus monodon Fabricius (1798).

    Science.gov (United States)

    Puthumana, Jayesh; Jose, Seena; Philip, Rosamma; Singh, I S Bright

    2015-12-01

    Lymphoid cell culture from penaeid shrimps has gained much acceptance as an in vitro platform to facilitate research on the development of prophylaxis, and therapeutic strategies against viruses and for cell line development. However, lymphoid cells can be used as platform for in vitro research, only if they are in metabolically and mitotically active state in vitro with unaltered cell surface receptors. Through this study, we addressed the response of lymphoid cells to a new microenvironment at cellular and molecular levels; including the study of mitotic events, DNA synthesis, expression profile of cell cycle genes, cytoskeleton organization, metabolic activity and viral susceptibility. The S-phase entry and synthesis of new DNA was recorded by immunoflourescent technique. Cdc2, CycA, CycB, EF-1α and BUB3 genes involved in cell cycle were studied in both the cells and tissue, of which EF-1α showed an elevated expression in cells in vitro (∼ 19.7%). Cytoskeleton network of the cell was examined by studying the organization of actin filaments. As the markers for metabolic status, mitochondrial dehydrogenase, protein synthesis and glucose assimilation by the cells were also assessed. Viral susceptibility of the cell was determined using WSSV to confirm the preservation of cellular receptors. This study envisages to strengthen the shrimp cell line research and to bring forth lymphoid cell culture system as a 'model' in vitro system for shrimp and crustaceans altogether.

  11. 竹柏属和罗汉松属叶输导组织的观察%Conducting Tissue of Leaves in Nageia and Podocarpus

    Institute of Scientific and Technical Information of China (English)

    孙同兴

    2008-01-01

    The conducting tissue structure of transverse and longitudinal sections was observed on leaves of Podocarpus and Nageia. Results showed: in Podocarpus leaves, there is only one midrib, the xylem tracheid of midrib vascular bundle is multi-form, transfusion tissue belongs to Cycas-type and transfusion tracheids are isodiametric, the accessory transfusion tracheids between palisade tissue and sponge tissue are developed; in Nageia leaves, there are plenty of parallel leaves, the xylem tracheids of each vein are relatively simple, transfusion tissue belongs to Taxus-type and transfusion tracheids are longer in longitudinal section than that in transverse section, the accessory transfusion tissue between palisade tissue and sponge tissue is absent. Considering other differences that in leaves of Podocarpus there are three resin ducts under vascular bundle of midrib, mesophyll cells are differentiated into palisade tissue and sponge tissue; in leaves of Nageia, there is only one resin duct under vascular bundle in each vein and no obvious differentiation in mesophyll cells, palisade tissue can be found on both sides, and sclereids can also be found in mesophyll tissue. The anatomical differences of leaf veins and mesophylls between Nageia and Podocarpus mentioned above support the viewpoint that Nageia and Podocarpus are two independent genera.

  12. Phytodiversity and conservation of Nithypooja Kona Sacred Grove of Nallamala Hill Range, Eastern Ghats, Andhra Pradesh

    Directory of Open Access Journals (Sweden)

    SKM Basha

    2015-06-01

    Full Text Available Sacred groves are climax forests and are the only representatives of natural or near-natural vegetation. These are dedicated to deities or ancestral spirits worshipped by local tribes along with surrounding plants and trees. These are ecosystems by themselves and perform all the ecological functions. Phytodiversity constitute a large segment of the flora which provides raw materials for use by numerous Pharmaceutical industries. The present study will be useful for researchers in the field of Ethan botany, Ethnomedicine, Taxonomy, and Pharmacology for further studies. Nithyapoojakona Sacred grove is one of the important sacred groves in Kadapa district. The present paper deals with the phyto-diversity of the above grove used by local tribes. This paper deals with the 181 species of probable medicinal potential belonging to 138 genera and 71 families. Significant flora are Cycas beddomei, Pterocarpus santalinus, Drosera burmaptonni, Orabanche cernua, Neptunia oleracea, Hugonia mystax, Caralluma adsendens , Gloriosa superba, Limnophila spp, Centella sasiatica etc. Word famous Red sanders population of the study area is being destroyed unethically and it is to be protected. DOI: http://dx.doi.org/10.3126/ije.v4i2.12648 International Journal of Environment Vol.4(2 2015: 271-288

  13. D-serine transporter in Staphylococcus saprophyticus identified.

    Science.gov (United States)

    Marlinghaus, Lennart; Huß, Melanie; Korte-Berwanger, Miriam; Sakinc-Güler, Türkan; Gatermann, Sören G

    2016-07-01

    Among staphylococci Staphylococcus saprophyticus is the only species that is typically uropathogenic and an important cause of urinary tract infections in young women. The amino acid D-serine occurs in relatively high concentrations in human urine and has a bacteriostatic or toxic effect on many bacteria. In uropathogenic Escherichia coli and S. saprophyticus, the amino acid regulates the expression of virulence factors and can be used as a nutrient. The ability of uropathogens to respond to or to metabolize D-serine has been suggested as a factor that enables colonization of the urinary tract. Until now nothing is known about D-serine transport in S. saprophyticus We generated mutants of putative transporter genes in S. saprophyticus 7108 that show homology to the D-serine transporter cycA of E. coli and tested them in a D-serine depletion assay to analyze the D-serine uptake rate of the cells. The mutant of SPP1070 showed a strong decrease in D-serine uptake. Therefore, SSP1070 was identified as a major D-serine transporter in S. saprophyticus 7108 and was named D-serine transporter A (DstA). D-serine caused a prolonged lag phase of S. saprophyticus in a chemically defined medium. This negative effect was dependent on the presence of DstA.

  14. OBSERVATIONS REGARDING EXISTING INVERTEBRATES FROM PLUM ORCHARDS

    Directory of Open Access Journals (Sweden)

    Mihai Tălmaciu

    2016-07-01

    Full Text Available The observations were made during the two years, 2013 and 2014 in a plantation belonging plum fruit growing from Teaching Station Vasile Adamachi of USAMV Iasi, Iasi County Rivers Early variety.Collecting the material was done with traps type Barber from May until August at intervals between 10 and 20 days. Collection of 2013 was made on the following dates: 20.05, 30.05, 15.06, 5.07, 25.07, 10.08 and 23.08.In total 2013 were collected 265 samples belonging to 22 species (taxa. Species (taxa with the largest number of samples collected were Dermestes laniarius L. 42 samples Heteroptera. (bedbugs with 38 samples, and Polydrosus sericeus Schall. 26 samples. In 2014 collection of the biological material was made on the following dates: 07.05, 21.05, 19.06, 08.07, 27.07, 15.08, 04.09. In total in 2014 were collected 744 samples belonging to 41 species (taxa with the highest number of samples were colected: Hymenoptera (bees with 92 saples, Orthoptera (locusts with 87 samples, Lepidoptera (larvae with 37samplres, and Homoptera (cycads with 31samples.

  15. A Collaborative Evaluation of LC-MS/MS Based Methods for BMAA Analysis: Soluble Bound BMAA Found to Be an Important Fraction

    Directory of Open Access Journals (Sweden)

    Elisabeth J. Faassen

    2016-02-01

    Full Text Available Exposure to β-N-methylamino-l-alanine (BMAA might be linked to the incidence of amyotrophic lateral sclerosis, Alzheimer’s disease and Parkinson’s disease. Analytical chemistry plays a crucial role in determining human BMAA exposure and the associated health risk, but the performance of various analytical methods currently employed is rarely compared. A CYANOCOST initiated workshop was organized aimed at training scientists in BMAA analysis, creating mutual understanding and paving the way towards interlaboratory comparison exercises. During this workshop, we tested different methods (extraction followed by derivatization and liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS analysis, or directly followed by LC-MS/MS analysis for trueness and intermediate precision. We adapted three workup methods for the underivatized analysis of animal, brain and cyanobacterial samples. Based on recovery of the internal standard D3BMAA, the underivatized methods were accurate (mean recovery 80% and precise (mean relative standard deviation 10%, except for the cyanobacterium Leptolyngbya. However, total BMAA concentrations in the positive controls (cycad seeds showed higher variation (relative standard deviation 21%–32%, implying that D3BMAA was not a good indicator for the release of BMAA from bound forms. Significant losses occurred during workup for the derivatized method, resulting in low recovery (<10%. Most BMAA was found in a trichloroacetic acid soluble, bound form and we recommend including this fraction during analysis.

  16. Conservation and canalization of gene expression during angiosperm diversification accompany the origin and evolution of the flower.

    Science.gov (United States)

    Chanderbali, André S; Yoo, Mi-Jeong; Zahn, Laura M; Brockington, Samuel F; Wall, P Kerr; Gitzendanner, Matthew A; Albert, Victor A; Leebens-Mack, James; Altman, Naomi S; Ma, Hong; dePamphilis, Claude W; Soltis, Douglas E; Soltis, Pamela S

    2010-12-28

    The origin and rapid diversification of the angiosperms (Darwin's "Abominable Mystery") has engaged generations of researchers. Here, we examine the floral genetic programs of phylogenetically pivotal angiosperms (water lily, avocado, California poppy, and Arabidopsis) and a nonflowering seed plant (a cycad) to obtain insight into the origin and subsequent evolution of the flower. Transcriptional cascades with broadly overlapping spatial domains, resembling the hypothesized ancestral gymnosperm program, are deployed across morphologically intergrading organs in water lily and avocado flowers. In contrast, spatially discrete transcriptional programs in distinct floral organs characterize the more recently derived angiosperm lineages represented by California poppy and Arabidopsis. Deep evolutionary conservation in the genetic programs of putatively homologous floral organs traces to those operating in gymnosperm reproductive cones. Female gymnosperm cones and angiosperm carpels share conserved genetic features, which may be associated with the ovule developmental program common to both organs. However, male gymnosperm cones share genetic features with both perianth (sterile attractive and protective) organs and stamens, supporting the evolutionary origin of the floral perianth from the male genetic program of seed plants.

  17. Potential plant poisonings in dogs and cats in southern Africa : review article

    Directory of Open Access Journals (Sweden)

    C.J. Botha

    2009-05-01

    Full Text Available Plant poisoning occurs less commonly in dogs and cats than in herbivorous livestock, but numerous cases have been documented worldwide, most of them caused by common and internationally widely cultivated ornamental garden and house plants. Few cases of poisoning of cats and dogs have been reported in southern Africa, but many of the plants that have caused poisoning in these species elsewhere are widely available in the subregion and are briefly reviewed in terms of toxic principles, toxicity, species affected, clinical signs, and prognosis. The list includes Melia azedarach (syringa, Brunfelsia spp. (yesterday, today and tomorrow, Datura stramonium (jimsonweed, stinkblaar, a wide variety of lilies and lily-like plants, cycads, plants that contain soluble oxalates, plants containing cardiac glycosides and other cardiotoxins and euphorbias (Euphorbia pulcherrima, E. tirucalli. Poisoning by plant products such as macadamia nuts, onions and garlic, grapes and raisins, cannabis (marijuana, dagga or hashish and castor oil seed or seedcake is also discussed. Many of the poisonings are not usually fatal, but others frequently result in death unless rapid action is taken by the owner and the veterinarian, underlining the importance of awareness of the poisonous potential of a number of familiar plants.

  18. Conservation and canalization of gene expression during angiosperm diversification accompany the origin and evolution of the flower

    Science.gov (United States)

    Chanderbali, André S.; Yoo, Mi-Jeong; Zahn, Laura M.; Brockington, Samuel F.; Wall, P. Kerr; Gitzendanner, Matthew A.; Albert, Victor A.; Leebens-Mack, James; Altman, Naomi S.; Ma, Hong; dePamphilis, Claude W.; Soltis, Douglas E.; Soltis, Pamela S.

    2010-01-01

    The origin and rapid diversification of the angiosperms (Darwin's “Abominable Mystery”) has engaged generations of researchers. Here, we examine the floral genetic programs of phylogenetically pivotal angiosperms (water lily, avocado, California poppy, and Arabidopsis) and a nonflowering seed plant (a cycad) to obtain insight into the origin and subsequent evolution of the flower. Transcriptional cascades with broadly overlapping spatial domains, resembling the hypothesized ancestral gymnosperm program, are deployed across morphologically intergrading organs in water lily and avocado flowers. In contrast, spatially discrete transcriptional programs in distinct floral organs characterize the more recently derived angiosperm lineages represented by California poppy and Arabidopsis. Deep evolutionary conservation in the genetic programs of putatively homologous floral organs traces to those operating in gymnosperm reproductive cones. Female gymnosperm cones and angiosperm carpels share conserved genetic features, which may be associated with the ovule developmental program common to both organs. However, male gymnosperm cones share genetic features with both perianth (sterile attractive and protective) organs and stamens, supporting the evolutionary origin of the floral perianth from the male genetic program of seed plants. PMID:21149731

  19. Identification of caleosin and two oleosin isoforms in oil bodies of pine megagametophytes.

    Science.gov (United States)

    Pasaribu, Buntora; Chung, Tse-Yu; Chen, Chii-Shiarng; Wang, Song-Liang; Jiang, Pei-Luen; Tzen, Jason T C

    2014-09-01

    Numerous oil bodies of 0.2-2 μm occupied approximately 80% of intracellular space in mature pine (Pinus massoniana) megagametophytes. They were stably isolated and found to comprise mostly triacylglycerols as examined by thin layer chromatography analysis and confirmed by both Nile red and BODIPY stainings. Fatty acids released from the triacylglycerols of pine oil bodies were mainly unsaturated, including linoleic acid (60%), adrenic acid (12.3%) and vaccenic acid (9.7%). Proteins extracted from pine oil bodies were subjected to immunological cross-recognition, and the results showed that three proteins of 28, 16 and 14 kDa were detected by antibodies against sesame seed caleosin, sesame oleosin-L and lily pollen oleosin-P, respectively. Complete cDNA fragments encoding these three pine oil-body proteins, tentatively named caleosin, oleosin-L and oleosin-G, were obtained by PCR cloning and further confirmed by mass spectrometric analysis. Consistently, phylogenetic tree analyses showed that pine caleosin was closely-related to the caleosin of cycad megagametophyte among known caleosin sequences. While pine oleosin-L was found clustered with seed oleosin isoforms of angiosperm species, oleosin-G was distinctively grouped with the oleosin-P of lily pollen. The oleosin-G identified in pine megagametophytes seems to represent a new class of seed oleosin isoform evolutionarily close to the pollen oleosin-P.

  20. Limonene, a citrus extract, for control of mealybugs and scale insects.

    Science.gov (United States)

    Hollingsworth, Robert G

    2005-06-01

    In a series of bioassays with mealybugs, aqueous solutions of 1% limonene were tested that used from 0.50 to 1.50% all purpose spray adjuvant (APSA)-80 as an emulsifier/surfactant. The two ingredients were added to water or to 0.1% Silwet L-77, an agricultural surfactant. Using 1% limonene, 0.75% APSA-80 and 0.1% Silwet L-77, a semitransparent mixture (primarily a microemulsion) was obtained that was safe for most plants and provided good control of mealybugs when sprayed or used in 1-min dips. Used at half strength, this mixture controlled > or =99% of whiteflies, whereas the full-strength mixture controlled from 69 to 100% of mealybugs and scales, including > or =93% control of root mealybugs. In side-by-side greenhouse tests, this mixture was superior to a 2% solution of insecticidal soap or a 2% solution of horticultural spray oil. Mortality of green scales on potted gardenia plants averaged 95, 89, and 88% on plants sprayed with limonene, insecticidal soap, or horticultural oil, respectively. In a related test, these same sprays killed 44.1, 22.7, or 12.5% of third and fourth instar clustering mealybugs, respectively. Limonene has promise as a safe, natural pesticide for insect pests on tolerant plants. Although 1% limonene solutions damaged certain species of ferns, gingers and delicate flowers, they caused no damage to ornamentals with thick, waxy leaves, such as palms, cycads, and orchids.

  1. Cenozoic extinctions account for the low diversity of extant gymnosperms compared with angiosperms.

    Science.gov (United States)

    Crisp, Michael D; Cook, Lyn G

    2011-12-01

    We test the widely held notion that living gymnosperms are 'ancient' and 'living fossils' by comparing them with their sister group, the angiosperms. This perception derives partly from the lack of gross morphological differences between some Mesozoic gymnosperm fossils and their living relatives (e.g. Ginkgo, cycads and dawn redwood), suggesting that the rate of evolution of gymnosperms has been slow. We estimated the ages and diversification rates of gymnosperm lineages using Bayesian relaxed molecular clock dating calibrated with 21 fossils, based on the phylogenetic analysis of alignments of matK chloroplast DNA (cpDNA) and 26S nuclear ribosomal DNA (nrDNA) sequences, and compared these with published estimates for angiosperms. Gymnosperm crown groups of Cenozoic age are significantly younger than their angiosperm counterparts (median age: 32 Ma vs 50 Ma) and have long unbranched stems, indicating major extinctions in the Cenozoic, in contrast with angiosperms. Surviving gymnosperm genera have diversified more slowly than angiosperms during the Neogene as a result of their higher extinction rate. Compared with angiosperms, living gymnosperm groups are not ancient. The fossil record also indicates that gymnosperms suffered major extinctions when climate changed in the Oligocene and Miocene. Extant gymnosperm groups occupy diverse habitats and some probably survived after making adaptive shifts.

  2. Long-Proboscid Flies as Pollinators of Cretaceous Gymnosperms.

    Science.gov (United States)

    Peñalver, Enrique; Arillo, Antonio; Pérez-de la Fuente, Ricardo; Riccio, Mark L; Delclòs, Xavier; Barrón, Eduardo; Grimaldi, David A

    2015-07-20

    The great evolutionary success of angiosperms has traditionally been explained, in part, by the partnership of these plants with insect pollinators. The main approach to understanding the origins of this pervasive relationship has been study of the pollinators of living cycads, gnetaleans, and basal angiosperms. Among the most morphologically specialized living pollinators are diverse, long-proboscid flies. Early such flies include the brachyceran family Zhangsolvidae, previously known only as compression fossils from the Early Cretaceous of China and Brazil. It belongs to the infraorder Stratiomyomorpha, a group that includes the flower-visiting families Xylomyidae and Stratiomyidae. New zhangsolvid specimens in amber from Spain (ca. 105 mega-annum [Ma]) and Myanmar (100 Ma) reveal a detailed proboscis structure adapted to nectivory. Pollen clumped on a specimen from Spain is Exesipollenites, attributed to a Mesozoic gymnosperm, most likely the Bennettitales. Late Mesozoic scorpionflies with a long proboscis have been proposed as specialized pollinators of various extinct gymnosperms, but pollen has never been observed on or in their bodies. The new discovery is a very rare co-occurrence of pollen with its insect vector and provides substantiating evidence that other long-proboscid Mesozoic insects were gymnosperm pollinators. Evidence is thus now gathering that visitors and probable pollinators of early anthophytes, or seed plants, involved some insects with highly specialized morphological adaptations, which has consequences for interpreting the reproductive modes of Mesozoic gymnosperms and the significance of insect pollination in angiosperm success.

  3. Seed plant phylogeny inferred from all three plant genomes: monophyly of extant gymnosperms and origin of Gnetales from conifers.

    Science.gov (United States)

    Chaw, S M; Parkinson, C L; Cheng, Y; Vincent, T M; Palmer, J D

    2000-04-11

    Phylogenetic relationships among the five groups of extant seed plants are presently quite unclear. For example, morphological studies consistently identify the Gnetales as the extant sister group to angiosperms (the so-called "anthophyte" hypothesis), whereas a number of molecular studies recover gymnosperm monophyly, and few agree with the morphology-based placement of Gnetales. To better resolve these and other unsettled issues, we have generated a new molecular data set of mitochondrial small subunit rRNA sequences, and have analyzed these data together with comparable data sets for the nuclear small subunit rRNA gene and the chloroplast rbcL gene. All nuclear analyses strongly ally Gnetales with a monophyletic conifers, whereas all mitochondrial analyses and those chloroplast analyses that take into account saturation of third-codon position transitions actually place Gnetales within conifers, as the sister group to the Pinaceae. Combined analyses of all three genes strongly support this latter relationship, which to our knowledge has never been suggested before. The combined analyses also strongly support monophyly of extant gymnosperms, with cycads identified as the basal-most group of gymnosperms, Ginkgo as the next basal, and all conifers except for Pinaceae as sister to the Gnetales + Pinaceae clade. According to these findings, the Gnetales may be viewed as extremely divergent conifers, and the many morphological similarities between angiosperms and Gnetales (e.g., double fertilization and flower-like reproductive structures) arose independently.

  4. Production of the Neurotoxin BMAA by a Marine Cyanobacterium

    Directory of Open Access Journals (Sweden)

    Paul Alan Cox

    2007-12-01

    Full Text Available Diverse species of cyanobacteria have recently been discovered to produce theneurotoxic non-protein amino acid β-methylamino-L-alanine (BMAA. In Guam, BMAAhas been studied as a possible environmental toxin in the diets of indigenous Chamorropeople known to have high levels of Amyotrophic Lateral Sclerosis/ ParkinsonismDementia Complex (ALS/PDC. BMAA has been found to accumulate in brain tissues ofpatients with progressive neurodegenerative illness in North America. In Guam, BMAAwas found to be produced by endosymbiotic cyanobacteria of the genus Nostoc which livein specialized cycad roots. We here report detection of BMAA in laboratory cultures of afree-living marine species of Nostoc. We successfully detected BMAA in this marinespecies of Nostoc with five different methods: HPLC-FD, UPLC-UV, Amino AcidAnalyzer, LC/MS, and Triple Quadrupole LC/MS/MS. This consensus of five differentanalytical methods unequivocally demonstrates the presence of BMAA in this marinecyanobacterium. Since protein-associated BMAA can accumulate in increasing levelswithin food chains, it is possible that biomagnification of BMAA could occur in marineecosystems similar to the biomagnification of BMAA in terrestrial ecosystems. Productionof BMAA by marine cyanobacteria may represent another route of human exposure toBMAA. Since BMAA at low concentrations causes the death of motor neurons, low levelsof BMAA exposure may trigger motor neuron disease in genetically vulnerableindividuals.

  5. Tectonic-driven climate change and the diversification of angiosperms.

    Science.gov (United States)

    Chaboureau, Anne-Claire; Sepulchre, Pierre; Donnadieu, Yannick; Franc, Alain

    2014-09-30

    In 1879, Charles Darwin characterized the sudden and unexplained rise of angiosperms during the Cretaceous as an "abominable mystery." The diversification of this clade marked the beginning of a rapid transition among Mesozoic ecosystems and floras formerly dominated by ferns, conifers, and cycads. Although the role of environmental factors has been suggested [Coiffard C, Gómez B (2012) Geol Acta 10(2):181-188], Cretaceous global climate change has barely been considered as a contributor to angiosperm radiation, and focus was put on biotic factors to explain this transition. Here we use a fully coupled climate model driven by Mesozoic paleogeographic maps to quantify and discuss the impact of continental drift on angiosperm expansion and diversification. We show that the decrease of desertic belts between the Triassic and the Cretaceous and the subsequent onset of long-lasting humid conditions during the Late Cretaceous were driven by the breakup of Pangea and were contemporaneous with the first rise of angiosperm diversification. Positioning angiosperm-bearing fossil sites on our paleobioclimatic maps shows a strong match between the location of fossil-rich outcrops and temperate humid zones, indicating that climate change from arid to temperate dominance may have set the stage for the ecological expansion of flowering plants.

  6. Prominent Human Health Impacts from Several Marine Microbes: History, Ecology, and Public Health Implications

    Directory of Open Access Journals (Sweden)

    P. K. Bienfang

    2011-01-01

    Full Text Available This paper overviews several examples of important public health impacts by marine microbes and directs readers to the extensive literature germane to these maladies. These examples include three types of dinoflagellates (Gambierdiscus spp., Karenia brevis, and Alexandrium fundyense, BMAA-producing cyanobacteria, and infectious microbes. The dinoflagellates are responsible for ciguatera fish poisoning, neurotoxic shellfish poisoning, and paralytic shellfish poisoning, respectively, that have plagued coastal populations over time. Research interest on the potential for marine cyanobacteria to contribute BMAA into human food supplies has been derived by BMAA's discovery in cycad seeds and subsequent implication as the putative cause of amyotrophic lateral sclerosis/parkinsonism dementia complex among the Chamorro people of Guam. Recent UPLC/MS analyses indicate that recent reports that BMAA is prolifically distributed among marine cyanobacteria at high concentrations may be due to analyte misidentification in the analytical protocols being applied for BMAA. Common infectious microbes (including enterovirus, norovirus, Salmonella, Campylobacter, Shigella, Staphylococcus aureus, Cryptosporidium, and Giardia cause gastrointestinal and skin-related illness. These microbes can be introduced from external human and animal sources, or they can be indigenous to the marine environment.

  7. Role of acyl carrier protein isoforms in plant lipid metabolism: Progress report

    Energy Technology Data Exchange (ETDEWEB)

    Ohlrogge, J.B.

    1989-01-01

    Previous research from my lab has revealed that several higher plant species have multiple isoforms of acyl carrier protein (ACP) and therefore this trait appears highly conserved among higher plants. This level of conservation suggests that the existence of ACP isoforms is not merely the results of neutral gene duplications. We have developed techniques to examine a wider range of species. Acyl carrier proteins can be labelled very specifically and to high specific activity using H-palmitate and the E. coli enzyme acyl-ACP synthetase. Isoforms were then resolved by western blotting and native PAGE of H-palmitate labelled ACP's. Multiple isoforms of ACP were observed the leaf tissue of the monocots Avena sativa and Hordeum vulgare and dicots including Arabidopsis thallina, Cuphea wrightii, and Brassica napus. Lower vascular plants including the cycad, Dioon edule, Ginkgo biloba, the gymnosperm Pinus, the fern Anernia phyllitidis and Psilotum nudum, the most primitive known extant vascular plant, were also found to have multiple ACP isoforms as were the nonvascular liverwort, Marchantia and moss, Polytrichum. Therefore, the development of ACP isoforms occurred early in evolution. However, the uniellular alge Chlamydomonas and Dunaliella and the photosynthetic cyanobacteria Synechocystis and Agmnellum have only a single elecrophotetic form of ACP. Thus, multiple forms of ACP do not occur in all photosynthetic organisms but may be associated with multicellular plants.

  8. Possible etiologies for tropical spastic paraparesis and human T lymphotropic virus I-associated myelopathy

    Directory of Open Access Journals (Sweden)

    V. Zaninovic'

    2004-01-01

    Full Text Available The epidemiology of tropical spastic paraparesis/human T lymphotropic virus I (HTLV-I-associated myelopathy (TSP/HAM is frequently inconsistent and suggests environmental factors in the etiology of these syndromes. The neuropathology corresponds to a toxometabolic or autoimmune process and possibly not to a viral disease. Some logical hypotheses about the etiology and physiopathology of TSP and HAM are proposed. Glutamate-mediated excitotoxicity, central distal axonopathies, cassava, lathyrism and cycad toxicity may explain most cases of TSP. The damage caused to astrocytes and to the blood-brain barrier by HTLV-I plus xenobiotics may explain most cases of HAM. Analysis of the HTLV-I/xenobiotic ratio clarifies most of the paradoxical epidemiology of TSP and HAM. Modern neurotoxicology, neuroimmunology and molecular biology may explain the neuropathology of TSP and HAM. It is quite possible that there are other xenobiotics implicated in the etiology of some TSP/HAMs. The prevention of these syndromes appears to be possible today.

  9. 宁夏海原南华山地区白垩系乃家河组的孢粉组合特征及时代古植被、古气候探讨%Sporopollen assemblage characteristics and discussion of Ancient vegetation,palaeoclimate at Cretaceous Na~jiahe Group in south Huashanof Haiyuan county in NingXia

    Institute of Scientific and Technical Information of China (English)

    王会明; 陆彦俊

    2012-01-01

    该文详细阐述了宁夏海原县南华山地区白垩系乃家河组的孢粉组合特征,进而对地层时代及古植被,古气候进行分析,得出这是一套早白垩世晚期的孢粉组合,表明当时六盘山一南华山地区的植被是以克拉梭粉的母体植物掌鳞杉为主的针叶林,林下覆盖着苏铁、麻黄和海金砂植物,气候干旱炎热。%In this paper,we research the Sporopollen assemblage characteristics and Ancient vegetation,palaeoclimate at Cretaceous Naijiahe Group from the geology,and we find that ,at the late Early Cretaceous ,the vegetation of Liupanshan--South hua mountain region is coniferous forest,with Classopoilis plants as dominant species .In the forest ,it is covered with cycads,ephedra and Lygodium plants.These shows that the climate is hot and dry in the area at that time.

  10. MatrixConverter: Facilitating construction of phenomic character matrices1

    Science.gov (United States)

    Liu, Jing; Endara, Lorena; Burleigh, J. Gordon

    2015-01-01

    • Premise of the study: While numerous software packages enable scientists to evaluate molecular data and transform them for phylogenetic analyses, few such tools exist for phenomic data. We introduce MatrixConverter, a program that helps expedite and facilitate the transformation of raw phenomic character data into discrete character matrices that can be used in most evolutionary inference programs. • Methods and Results: MatrixConverter is an open source program written in Java; a platform-independent binary executable, as well as sample data sets and a user’s manual, are available at https://github.com/gburleigh/MatrixConverter/tree/master/distribution. MatrixConverter has a simple, intuitive user interface that enables the user to immediately begin scoring phenomic characters. We demonstrate the performance of MatrixConverter on a phenomic data set from cycads. • Conclusions: New technologies and software make it possible to obtain phenomic data from species across the tree of life, and MatrixConverter helps to transform these new data for evolutionary or ecological inference. PMID:25699217

  11. Does Size Matter? Atmospheric CO2 May Be a Stronger Driver of Stomatal Closing Rate Than Stomatal Size in Taxa That Diversified under Low CO2

    Science.gov (United States)

    Elliott-Kingston, Caroline; Haworth, Matthew; Yearsley, Jon M.; Batke, Sven P.; Lawson, Tracy; McElwain, Jennifer C.

    2016-01-01

    One strategy for plants to optimize stomatal function is to open and close their stomata quickly in response to environmental signals. It is generally assumed that small stomata can alter aperture faster than large stomata. We tested the hypothesis that species with small stomata close faster than species with larger stomata in response to darkness by comparing rate of stomatal closure across an evolutionary range of species including ferns, cycads, conifers, and angiosperms under controlled ambient conditions (380 ppm CO2; 20.9% O2). The two species with fastest half-closure time and the two species with slowest half-closure time had large stomata while the remaining three species had small stomata, implying that closing rate was not correlated with stomatal size in these species. Neither was response time correlated with stomatal density, phylogeny, functional group, or life strategy. Our results suggest that past atmospheric CO2 concentration during time of taxa diversification may influence stomatal response time. We show that species which last diversified under low or declining atmospheric CO2 concentration close stomata faster than species that last diversified in a high CO2 world. Low atmospheric [CO2] during taxa diversification may have placed a selection pressure on plants to accelerate stomatal closing to maintain adequate internal CO2 and optimize water use efficiency. PMID:27605929

  12. A Collaborative Evaluation of LC-MS/MS Based Methods for BMAA Analysis: Soluble Bound BMAA Found to Be an Important Fraction

    Science.gov (United States)

    Faassen, Elisabeth J.; Antoniou, Maria G.; Beekman-Lukassen, Wendy; Blahova, Lucie; Chernova, Ekaterina; Christophoridis, Christophoros; Combes, Audrey; Edwards, Christine; Fastner, Jutta; Harmsen, Joop; Hiskia, Anastasia; Ilag, Leopold L.; Kaloudis, Triantafyllos; Lopicic, Srdjan; Lürling, Miquel; Mazur-Marzec, Hanna; Meriluoto, Jussi; Porojan, Cristina; Viner-Mozzini, Yehudit; Zguna, Nadezda

    2016-01-01

    Exposure to β-N-methylamino-l-alanine (BMAA) might be linked to the incidence of amyotrophic lateral sclerosis, Alzheimer’s disease and Parkinson’s disease. Analytical chemistry plays a crucial role in determining human BMAA exposure and the associated health risk, but the performance of various analytical methods currently employed is rarely compared. A CYANOCOST initiated workshop was organized aimed at training scientists in BMAA analysis, creating mutual understanding and paving the way towards interlaboratory comparison exercises. During this workshop, we tested different methods (extraction followed by derivatization and liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) analysis, or directly followed by LC-MS/MS analysis) for trueness and intermediate precision. We adapted three workup methods for the underivatized analysis of animal, brain and cyanobacterial samples. Based on recovery of the internal standard D3BMAA, the underivatized methods were accurate (mean recovery 80%) and precise (mean relative standard deviation 10%), except for the cyanobacterium Leptolyngbya. However, total BMAA concentrations in the positive controls (cycad seeds) showed higher variation (relative standard deviation 21%–32%), implying that D3BMAA was not a good indicator for the release of BMAA from bound forms. Significant losses occurred during workup for the derivatized method, resulting in low recovery (<10%). Most BMAA was found in a trichloroacetic acid soluble, bound form and we recommend including this fraction during analysis. PMID:26938542

  13. Equilibrium Dynamics of β-N-Methylamino-L-Alanine (BMAA) and Its Carbamate Adducts at Physiological Conditions

    Science.gov (United States)

    Zimmerman, David; Goto, Joy J.; Krishnan, Viswanathan V

    2016-01-01

    Elevated incidences of Amyotrophic Lateral Sclerosis/Parkinsonism Dementia complex (ALS/PDC) is associated with β-methylamino-L-alanine (BMAA), a non-protein amino acid. In particular, the native Chamorro people living in the island of Guam were exposed to BMAA by consuming a diet based on the cycad seeds. Carbamylated forms of BMAA are glutamate analogues. The mechanism of neurotoxicity of the BMAA is not completely understood, and BMAA acting as a glutamate receptor agonist may lead to excitotoxicity that interferes with glutamate transport systems. Though the interaction of BMAA with bicarbonate is known to produce carbamate adducts, here we demonstrate that BMAA and its primary and secondary adducts coexist in solution and undergoes a chemical exchange among them. Furthermore, we determined the rates of formation/cleavage of the carbamate adducts under equilibrium conditions using two-dimensional proton exchange NMR spectroscopy (EXSY). The coexistence of the multiple forms of BMAA at physiological conditions adds to the complexity of the mechanisms by which BMAA functions as a neurotoxin. PMID:27513925

  14. Late Carboniferous palaeobotany of the upper Bideford Formation, north Devon: a coastal setting for a Coal Measures flora

    Energy Technology Data Exchange (ETDEWEB)

    Cleal, C.J.; Thomas, B.A. [Natural Museums & Galleries Wales, Cardiff (United Kingdom)

    2004-07-01

    The Culm Seams are thin coals in the Upper Carboniferous upper Bideford Formation of north Devon. Clastic sedimentary rocks associated with the coals have yielded a fossil macroflora dominated by the remains of the Calamostachyales and Medullosales, together with subsidiary lycophytes, sphenophylls, ferns, lagenostomaleans, rare cordaites, and a possible early cycad. The flora is probably early Langsettian in age, which is in agreement with the evidence of the non-marine bivalves and marine bands. It is broadly similar in composition to contemporaneous macrofloras from South Wales. It is unlikely to represent an assemblage formed from plant remains subject to long-distance transportation. Rather, it was probably preserved in the lower reaches of a 'bird-foot' delta that had temporarily transgressed into the Culm Basin. The distal margin of this delta would represent a comparable habitat to the levees of the rivers further inland, and thus would have supported vegetation similar to that which generated the more usual Coal Measures macrofloras.

  15. The Late Cretaceous Aarya flora of the northern Okhotsk region and phytostratigraphy of the lower part of the Okhotsk-Chukotka volcanogenic belt section

    Science.gov (United States)

    Shczepetov, S. V.; Golovneva, L. B.

    2014-07-01

    The Zarya flora comes from volcanogenic sedimentary rocks of the Zarya and Parnyi formations that correspond to the basal part of the section of the Okhotsk-Chukotka volcanogenic belt in the Omsukchan district (Magadan oblast, Russia). The revision of its taxonomic composition resulted in identifying approximately 25 species of horsetails, ferns, cycads, ginkgoalens, czekanowskians, conifers, and angiosperms. The Zarya flora is characterized by a combination of the Early Cretaceous relicts ( Hausmannia, Birisia, Sphenobaiera, Phoenicopsis, Nilssonia, Podozamites) and typical Late Cretaceous taxa ( Taxodium, Sequoia, Menispermites, Dalembia, Trochodendroides, Cissites, Terechovia, Platanaceae). Among all the paleofloral assemblages of the Okhotsk-Chukotka volcanogenic belt, the Zarya flora is the most similar to the Turonian-Coniacian Arman flora of the Magadan region, which indicates their synchronism and floral unity. The Chingandzha flora of the Omsukchan area, which comes from the same stratigraphic level as Zarya flora, differs substantially from the latter in its taxonomic composition. It is conceivable that the Chingandzha flora was confined to a large river valley which was connected to coastal lowlands. The plant remains of the Arman flora with many mountain relicts could be buried in sediments of intermountain troughs isolated from coastal lowlands. Araucarites ochotensis sp. nov. is described.

  16. Equilibrium Dynamics of β-N-Methylamino-L-Alanine (BMAA) and Its Carbamate Adducts at Physiological Conditions.

    Science.gov (United States)

    Zimmerman, David; Goto, Joy J; Krishnan, Viswanathan V

    2016-01-01

    Elevated incidences of Amyotrophic Lateral Sclerosis/Parkinsonism Dementia complex (ALS/PDC) is associated with β-methylamino-L-alanine (BMAA), a non-protein amino acid. In particular, the native Chamorro people living in the island of Guam were exposed to BMAA by consuming a diet based on the cycad seeds. Carbamylated forms of BMAA are glutamate analogues. The mechanism of neurotoxicity of the BMAA is not completely understood, and BMAA acting as a glutamate receptor agonist may lead to excitotoxicity that interferes with glutamate transport systems. Though the interaction of BMAA with bicarbonate is known to produce carbamate adducts, here we demonstrate that BMAA and its primary and secondary adducts coexist in solution and undergoes a chemical exchange among them. Furthermore, we determined the rates of formation/cleavage of the carbamate adducts under equilibrium conditions using two-dimensional proton exchange NMR spectroscopy (EXSY). The coexistence of the multiple forms of BMAA at physiological conditions adds to the complexity of the mechanisms by which BMAA functions as a neurotoxin.

  17. Extant primitively segmented spiders have recently diversified from an ancient lineage.

    Science.gov (United States)

    Xu, Xin; Liu, Fengxiang; Cheng, Ren-Chung; Chen, Jian; Xu, Xiang; Zhang, Zhisheng; Ono, Hirotsugu; Pham, Dinh Sac; Norma-Rashid, Y; Arnedo, Miquel A; Kuntner, Matjaž; Li, Daiqin

    2015-06-07

    Living fossils are lineages that have retained plesiomorphic traits through long time periods. It is expected that such lineages have both originated and diversified long ago. Such expectations have recently been challenged in some textbook examples of living fossils, notably in extant cycads and coelacanths. Using a phylogenetic approach, we tested the patterns of the origin and diversification of liphistiid spiders, a clade of spiders considered to be living fossils due to their retention of arachnid plesiomorphies and their exclusive grouping in Mesothelae, an ancient clade sister to all modern spiders. Facilitated by original sampling throughout their Asian range, we here provide the phylogenetic framework necessary for reconstructing liphistiid biogeographic history. All phylogenetic analyses support the monophyly of Liphistiidae and of eight genera. As the fossil evidence supports a Carboniferous Euramerican origin of Mesothelae, our dating analyses postulate a long eastward over-land dispersal towards the Asian origin of Liphistiidae during the Palaeogene (39-58 Ma). Contrary to expectations, diversification within extant liphistiid genera is relatively recent, in the Neogene and Late Palaeogene (4-24 Ma). While no over-water dispersal events are needed to explain their evolutionary history, the history of liphistiid spiders has the potential to play prominently in vicariant biogeographic studies. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

  18. Evolution and biogeography of gymnosperms.

    Science.gov (United States)

    Wang, Xiao-Quan; Ran, Jin-Hua

    2014-06-01

    Living gymnosperms comprise only a little more than 1000 species, but represent four of the five main lineages of seed plants, including cycads, ginkgos, gnetophytes and conifers. This group has huge ecological and economic value, and has drawn great interest from the scientific community. Here we review recent advances in our understanding of gymnosperm evolution and biogeography, including phylogenetic relationships at different taxonomic levels, patterns of species diversification, roles of vicariance and dispersal in development of intercontinental disjunctions, modes of molecular evolution in different genomes and lineages, and mechanisms underlying the formation of large nuclear genomes. It is particularly interesting that increasing evidence supports a sister relationship between Gnetales and Pinaceae (the Gnepine hypothesis) and the contribution of recent radiations to present species diversity, and that expansion of retrotransposons is responsible for the large and complex nuclear genome of gymnosperms. In addition, multiple coniferous genera such as Picea very likely originated in North America and migrated into the Old World, further indicating that the center of diversity is not necessarily the place of origin. The Bering Land Bridge acted as an important pathway for dispersal of gymnosperms in the Northern Hemisphere. Moreover, the genome sequences of conifers provide an unprecedented opportunity and an important platform for the evolutionary studies of gymnosperms, and will also shed new light on evolution of many important gene families and biological pathways in seed plants. Copyright © 2014 Elsevier Inc. All rights reserved.

  19. Mutation of the cytosolic ribosomal protein-encoding RPS10B gene affects shoot meristematic function in Arabidopsis

    Directory of Open Access Journals (Sweden)

    Stirnberg Petra

    2012-09-01

    Full Text Available Abstract Background Plant cytosolic ribosomal proteins are encoded by small gene families. Mutants affecting these genes are often viable, but show growth and developmental defects, suggesting incomplete functional redundancy within the families. Dormancy to growth transitions, such as the activation of axillary buds in the shoot, are characterised by co-ordinated upregulation of ribosomal protein genes. Results A recessive mutation in RPS10B, one of three Arabidopsis genes encoding the eukaryote-specific cytoplasmic ribosomal protein S10e, was found to suppress the excessive shoot branching mutant max2-1. rps10b-1 mildly affects the formation and separation of shoot lateral organs, including the shoot axillary meristems. Axillary meristem defects are enhanced when rps10b-1 is combined with mutations in REVOLUTA, AUXIN-RESISTANT1, PINOID or another suppressor of max2-1, FAR-RED ELONGATED HYPOCOTYL3. In some of these double mutants, the maintenance of the primary shoot meristem is also affected. In contrast, mutation of ALTERED MERISTEM PROGRAMME1 suppresses the rps10b-1axillary shoot defect. Defects in both axillary shoot formation and organ separation were enhanced by combining rps10b-1 with cuc3, a mutation affecting one of three Arabidopsis NAC transcription factor genes with partially redundant roles in these processes. To assess the effect of rps10b-1 on bud activation independently from bud formation, axillary bud outgrowth on excised cauline nodes was analysed. The outgrowth rate of untreated buds was reduced only slightly by rps10b-1 in both wild-type and max2-1 backgrounds. However, rps10b-1 strongly suppressed the auxin resistant outgrowth of max2-1 buds. A developmental phenotype of rps10b-1, reduced stamen number, was complemented by the cDNA of another family member, RPS10C, under the RPS10B promoter. Conclusions RPS10B promotes shoot branching mainly by promoting axillary shoot development. It contributes to organ boundary

  20. Auxin-induced hydrogen sulfide generation is involved in lateral root formation in tomato.

    Science.gov (United States)

    Fang, Tao; Cao, Zeyu; Li, Jiale; Shen, Wenbiao; Huang, Liqin

    2014-03-01

    Similar to auxin, hydrogen sulfide (H2S), mainly produced by l-cysteine desulfhydrase (DES; EC 4.4.1.1) in plants, could induce lateral root formation. The objective of this study was to test whether H2S is also involved in auxin-induced lateral root development in tomato (Solanum lycopersicum L.) seedlings. We observed that auxin depletion-induced down-regulation of transcripts of SlDES1, decreased DES activity and endogenous H2S contents, and the inhibition of lateral root formation were rescued by sodium hydrosulfide (NaHS, an H2S donor). However, No additive effects were observed when naphthalene acetic acid (NAA) was co-treated with NaHS (lower than 10 mM) in the induction of lateral root formation. Subsequent work revealed that a treatment with NAA or NaHS could simultaneously induce transcripts of SlDES1, DES activity and endogenous H2S contents, and thereafter the stimulation of lateral root formation. It was further confirmed that H2S or HS(-), not the other sulfur-containing components derived from NaHS, was attributed to the stimulative action. The inhibition of lateral root formation and decreased of H2S metabolism caused by an H2S scavenger hypotaurine (HT) were reversed by NaHS, but not NAA. Molecular evidence revealed that both NaHS- or NAA-induced modulation of some cell cycle regulatory genes, including the up-regulation of SlCDKA;1, SlCYCA2;1, together with simultaneous down-regulation of SlKRP2, were differentially reversed by HT pretreatment. To summarize, above results clearly suggested that H2S might, at least partially, act as a downstream component of auxin signaling to trigger lateral root formation.

  1. Heme oxygenase-1 is involved in sodium hydrosulfide-induced lateral root formation in tomato seedlings.

    Science.gov (United States)

    Fang, Tao; Li, Jiale; Cao, Zeyu; Chen, Meng; Shen, Wei; Huang, Liqin

    2014-06-01

    By using pharmacological and molecular approaches, we discovered the involvement of HO-1 in NaHS-induced lateral root formation in tomato seedlings. Heme oxygenase-1 (HO-1) and hydrogen sulfide (H2S) regulate various responses to abiotic stress and root development, but their involvement in the simultaneous regulation of plant lateral root (LR) formation is poorly understood. In this report, we observed that the exogenously applied H2S donor sodium hydrosulfide (NaHS) and the HO-1 inducer hemin induce LR formation in tomato seedlings by triggering intracellular signaling events involving the induction of tomato HO-1 (SlHO-1), and the modulation of cell cycle regulatory genes, including the up-regulation of SlCDKA;1 and SlCYCA2;1, and simultaneous down-regulation of SlKRP2. The response of NaHS in the induction of LR formation was impaired by the potent inhibition of HO-1, which was further blocked when 50 % saturation of carbon monoxide (CO) aqueous solution, one of the catalytic by-products of HO-1, was added. Further molecular evidence revealed that the NaHS-modulated gene expression of cell cycle regulatory genes was sensitive to the inhibition of HO-1 and reversed by cotreatment with CO. The impairment of LR density and length as well as lateral root primordia number, the decreased tomato HO-1 gene expression and HO activity caused by an H2S scavenger hypotaurine were partially rescued by the addition of NaHS, hemin and CO (in particular). Together, these results revealed that at least in our experimental conditions, HO-1 might be involved in NaHS-induced tomato LR formation. Additionally, the use of NaHS and hemin compounds in crop root organogenesis should be explored.

  2. A proposed conserved role for an avocado FW2.2-like gene as a negative regulator of fruit cell division.

    Science.gov (United States)

    Dahan, Yardena; Rosenfeld, Revital; Zadiranov, Victor; Irihimovitch, Vered

    2010-08-01

    Previous studies using 'Hass' avocado and its small fruit (SF) phenotype as a model showed that SF is limited by cell number, not by cell size. In an attempt to explore the molecular mechanisms regulating avocado fruit cell division, we isolated four distinct avocado cell proliferation-related genes and investigated their expression characteristics, comparing normal fruit (NF) and SF developmental patterns. Three cDNAs termed PaCYCA1, PaCYCB1 and PaPCNA, encoding two mitotic cyclins and a proliferating cell nuclear antigen (PCNA), were first isolated from young NF tissues. The accumulation of their transcripts was predominant in mitotically active organs, including young fruitlets, leaves and roots. Furthermore, a fourth full-length cDNA, designated Pafw2.2-like, encoding a FW2.2 (fruit-weight)-like protein, was isolated from SF tissues. FW2.2 is postulated to function as a negative regulator of cell division in tomato fruit. Remarkably, northern analysis revealed that the accumulation of the mitotic cyclins and of PCNA transcripts gradually decreased in NF tissues during growth, whereas in SF, their levels had already decreased at earlier stages of fruit development, concomitant with an earlier arrest of fruit cell division activity. In contrast, parallel sq-RT-PCR analysis showed that Pafw2.2-like mRNA accumulation was considerably higher in SF tissues than in the same NF tissues essentially at all examined stages of fruit growth. Together, our data suggest essential roles for the two mitotic cyclins genes and the PCNA gene in regulating avocado fruit development. Furthermore, the possibility that Pafw2.2-like acts as does fw2.2 in tomato, is discussed.

  3. Transcriptome Analysis Reveals Candidate Genes Involved in Gibberellin-Induced Fruit Setting in Triploid Loquat (Eriobotrya japonica)

    Science.gov (United States)

    Jiang, Shuang; Luo, Jun; Xu, Fanjie; Zhang, Xueying

    2016-01-01

    The triploid loquat (Eriobotrya japonica) is a new germplasm with a high edible fruit rate. Under natural conditions, the triploid loquat has a low fruit setting ratio (not more than 10 fruits in a tree), reflecting fertilization failure. To unravel the molecular mechanism of gibberellin (GA) treatment to induce parthenocarpy in triploid loquats, a transcriptome analysis of fruit setting induced by GA3 was analyzed using RNA-seq at four different stages during the development of young fruit. Approximately 344 million high quality reads in seven libraries were de novo assembled, yielding 153,900 unique transcripts with more than 79.9% functionally annotated transcripts. A total of 2,220, 2,974, and 1,614 differentially expressed genes (DEGs) were observed at 3, 7, and 14 days after GA treatment, respectively. The weighted gene co-expression network and Venn diagram analysis of DEGs revealed that sixteen candidate genes may play critical roles in the fruit setting after GA treatment. Five genes were related to auxin, in which one auxin synthesis gene of yucca was upregulated, suggesting that auxin may act as a signal for fruit setting. Furthermore, ABA 8′-hydroxylase was upregulated, while ethylene-forming enzyme was downregulated, suggesting that multiple hormones may be involved in GA signaling. Four transcription factors, NAC7, NAC23, bHLH35, and HD16, were potentially negatively regulated in fruit setting, and two cell division-related genes, arr9 and CYCA3, were upregulated. In addition, the expression of the GA receptor gid1 was downregulated by GA treatment, suggesting that the negative feedback mechanism in GA signaling may be regulated by gid1. Altogether, the results of the present study provide information from a comprehensive gene expression analysis and insight into the molecular mechanism underlying fruit setting under GA treatment in E. japonica. PMID:28066478

  4. Roles of serine accumulation and catabolism in the colonization of the murine urinary tract by Escherichia coli CFT073.

    Science.gov (United States)

    Anfora, Andrew T; Haugen, Brian J; Roesch, Paula; Redford, Peter; Welch, Rodney A

    2007-11-01

    A D-serine deaminase (DsdA) mutant of uropathogenic Escherichia coli strain CFT073 has a hypercolonization phenotype in a murine model of urinary tract infection (UTI) due to increased virulence gene expression by an unknown mechanism (B. J. Haugen et al., Infect. Immun. 75:278-289, 2007). DsdC is a D-serine-dependent activator of dsdXA transcription. DsdC may regulate the virulence genes responsible for hypercolonization. The loss of DsdA leads to increased intracellular accumulation of D-serine. In this study we show that deletion of the genes encoding L-serine deaminases SdaA and SdaB resulted in a mutant that accumulates higher intracellular levels of L-serine than CFT073. CFT073 sdaA sdaB has a mild competitive colonization defect whereas a CFT073 dsdA sdaA sdaB triple mutant shows a greater loss in competitive colonization ability. Thus, the inability to generate serine-specific catabolic products does not result in hypercolonization and the ability to catabolize serine represents a positive physiological trait during murine UTI. CFT073 dsdC and CFT073 dsdC dsdA mutants continue to outcompete the wild type in the UTI model. These results confirm that loss of DsdA activity results in the hypercolonization phenotype and that DsdC does not play a direct role in the elevated-colonization phenotype. Interestingly, a CFT073 dsdA mutant with deletions of D-serine transporter genes dsdX and cycA shows wild-type colonization levels of the bladder but is attenuated for kidney colonization. Thus, D-serine acts as a signal for hypercolonization and virulence gene expression by CFT073 dsdA, whereas overall catabolism of serine represents a positive Escherichia coli fitness trait during UTI.

  5. Roles of Serine Accumulation and Catabolism in the Colonization of the Murine Urinary Tract by Escherichia coli CFT073▿

    Science.gov (United States)

    Anfora, Andrew T.; Haugen, Brian J.; Roesch, Paula; Redford, Peter; Welch, Rodney A.

    2007-01-01

    A d-serine deaminase (DsdA) mutant of uropathogenic Escherichia coli strain CFT073 has a hypercolonization phenotype in a murine model of urinary tract infection (UTI) due to increased virulence gene expression by an unknown mechanism (B. J. Haugen et al., Infect. Immun. 75:278-289, 2007). DsdC is a d-serine-dependent activator of dsdXA transcription. DsdC may regulate the virulence genes responsible for hypercolonization. The loss of DsdA leads to increased intracellular accumulation of d-serine. In this study we show that deletion of the genes encoding l-serine deaminases SdaA and SdaB resulted in a mutant that accumulates higher intracellular levels of l-serine than CFT073. CFT073 sdaA sdaB has a mild competitive colonization defect whereas a CFT073 dsdA sdaA sdaB triple mutant shows a greater loss in competitive colonization ability. Thus, the inability to generate serine-specific catabolic products does not result in hypercolonization and the ability to catabolize serine represents a positive physiological trait during murine UTI. CFT073 dsdC and CFT073 dsdC dsdA mutants continue to outcompete the wild type in the UTI model. These results confirm that loss of DsdA activity results in the hypercolonization phenotype and that DsdC does not play a direct role in the elevated-colonization phenotype. Interestingly, a CFT073 dsdA mutant with deletions of d-serine transporter genes dsdX and cycA shows wild-type colonization levels of the bladder but is attenuated for kidney colonization. Thus, d-serine acts as a signal for hypercolonization and virulence gene expression by CFT073 dsdA, whereas overall catabolism of serine represents a positive Escherichia coli fitness trait during UTI. PMID:17785472

  6. A critical role for the cccA gene product, cytochrome c2, in diverting electrons from aerobic respiration to denitrification in Neisseria gonorrhoeae.

    Science.gov (United States)

    Hopper, Amanda C; Li, Ying; Cole, Jeffrey A

    2013-06-01

    Neisseria gonorrhoeae is a microaerophile that, when oxygen availability is limited, supplements aerobic respiration with a truncated denitrification pathway, nitrite reduction to nitrous oxide. We demonstrate that the cccA gene of Neisseria gonorrhoeae strain F62 (accession number NG0292) is expressed, but the product, cytochrome c2, accumulates to only low levels. Nevertheless, a cccA mutant reduced nitrite at about half the rate of the parent strain. We previously reported that cytochromes c4 and c5 transfer electrons to cytochrome oxidase cbb3 by two independent pathways and that the CcoP subunit of cytochrome oxidase cbb3 transfers electrons to nitrite. We show that mutants defective in either cytochrome c4 or c5 also reduce nitrite more slowly than the parent. By combining mutations in cccA (Δc2), cycA (Δc4), cycB (Δc5), and ccoP (ccoP-C368A), we demonstrate that cytochrome c2 is required for electron transfer from cytochrome c4 via the third heme group of CcoP to the nitrite reductase, AniA, and that cytochrome c5 transfers electrons to nitrite reductase by an independent pathway. We propose that cytochrome c2 forms a complex with cytochrome oxidase. If so, the redox state of cytochrome c2 might regulate electron transfer to nitrite or oxygen. However, our data are more consistent with a mechanism in which cytochrome c2 and the CcoQ subunit of cytochrome oxidase form alternative complexes that preferentially catalyze nitrite and oxygen reduction, respectively. Comparison with the much simpler electron transfer pathway for nitrite reduction in the meningococcus provides fascinating insights into niche adaptation within the pathogenic neisseriae.

  7. The Complete Mitochondrial Genome of Gossypium hirsutum and Evolutionary Analysis of Higher Plant Mitochondrial Genomes

    Science.gov (United States)

    Su, Aiguo; Geng, Jianing; Grover, Corrinne E.; Hu, Songnian; Hua, Jinping

    2013-01-01

    Background Mitochondria are the main manufacturers of cellular ATP in eukaryotes. The plant mitochondrial genome contains large number of foreign DNA and repeated sequences undergone frequently intramolecular recombination. Upland Cotton (Gossypium hirsutum L.) is one of the main natural fiber crops and also an important oil-producing plant in the world. Sequencing of the cotton mitochondrial (mt) genome could be helpful for the evolution research of plant mt genomes. Methodology/Principal Findings We utilized 454 technology for sequencing and combined with Fosmid library of the Gossypium hirsutum mt genome screening and positive clones sequencing and conducted a series of evolutionary analysis on Cycas taitungensis and 24 angiosperms mt genomes. After data assembling and contigs joining, the complete mitochondrial genome sequence of G. hirsutum was obtained. The completed G.hirsutum mt genome is 621,884 bp in length, and contained 68 genes, including 35 protein genes, four rRNA genes and 29 tRNA genes. Five gene clusters are found conserved in all plant mt genomes; one and four clusters are specifically conserved in monocots and dicots, respectively. Homologous sequences are distributed along the plant mt genomes and species closely related share the most homologous sequences. For species that have both mt and chloroplast genome sequences available, we checked the location of cp-like migration and found several fragments closely linked with mitochondrial genes. Conclusion The G. hirsutum mt genome possesses most of the common characters of higher plant mt genomes. The existence of syntenic gene clusters, as well as the conservation of some intergenic sequences and genic content among the plant mt genomes suggest that evolution of mt genomes is consistent with plant taxonomy but independent among different species. PMID:23940520

  8. The Mitochondrial Genome of Raphanus sativus and Gene Evolution of Cruciferous Mitochondrial Types

    Institute of Scientific and Technical Information of China (English)

    Shengxin Chang; Jianmei Chen; Yankun Wang; Bingchao Gu; Jianbo He; Pu Chu; Rongzhan Guan

    2013-01-01

    To explore the mitochondrial genes of the Cruciferae family,the mitochondrial genome of Raphanus sativus (sat) was sequenced and annotated.The circular mitochondrial genome of sat is 239,723 bp and includes 33 protein-coding genes,three rRNA genes and 17 tRNA genes.The mitochondrial genome also contains a pair of large repeat sequences 5.9 kb in length,which may mediate genome reorganization into two sub-genomic circles,with predicted sizes of 124.8 kb and 115.0 kb,respectively.Furthermore,gene evolution of mitochondrial genomes within the Cruciferae family was analyzed using sat mitochondrial type (mitotype),together with six other reported mitotypes.The cruciferous mitochondrial genomes have maintained almost the same set of functional genes.Compared with Cycas taitungensis (a representative gymnosperm),the mitochondrial genomes of the Cruciferae have lost nine protein-coding genes and seven mitochondrial-like tRNA genes,but acquired six chloroplast-like tRNAs.Among the Cruciferae,to maintain the same set of genes that are necessary for mitochondrial function,the exons of the genes have changed at the lowest rates,as indicated by the numbers of single nucleotide polymorphisms.The open reading frames (ORFs) of unknown function in the cruciferous genomes are not conserved.Evolutionary events,such as mutations,genome reorganizations and sequence insertions or deletions (indels),have resulted in the nonconserved ORFs in the cruciferous mitochondrial genomes,which is becoming significantly different among mitotypes.This work represents the first phylogenic explanation of the evolution of genes of known function in the Cruciferae family.It revealed significant variation in ORFs and the causes of such variation.

  9. The complete mitochondrial genome of Gossypium hirsutum and evolutionary analysis of higher plant mitochondrial genomes.

    Directory of Open Access Journals (Sweden)

    Guozheng Liu

    Full Text Available BACKGROUND: Mitochondria are the main manufacturers of cellular ATP in eukaryotes. The plant mitochondrial genome contains large number of foreign DNA and repeated sequences undergone frequently intramolecular recombination. Upland Cotton (Gossypium hirsutum L. is one of the main natural fiber crops and also an important oil-producing plant in the world. Sequencing of the cotton mitochondrial (mt genome could be helpful for the evolution research of plant mt genomes. METHODOLOGY/PRINCIPAL FINDINGS: We utilized 454 technology for sequencing and combined with Fosmid library of the Gossypium hirsutum mt genome screening and positive clones sequencing and conducted a series of evolutionary analysis on Cycas taitungensis and 24 angiosperms mt genomes. After data assembling and contigs joining, the complete mitochondrial genome sequence of G. hirsutum was obtained. The completed G.hirsutum mt genome is 621,884 bp in length, and contained 68 genes, including 35 protein genes, four rRNA genes and 29 tRNA genes. Five gene clusters are found conserved in all plant mt genomes; one and four clusters are specifically conserved in monocots and dicots, respectively. Homologous sequences are distributed along the plant mt genomes and species closely related share the most homologous sequences. For species that have both mt and chloroplast genome sequences available, we checked the location of cp-like migration and found several fragments closely linked with mitochondrial genes. CONCLUSION: The G. hirsutum mt genome possesses most of the common characters of higher plant mt genomes. The existence of syntenic gene clusters, as well as the conservation of some intergenic sequences and genic content among the plant mt genomes suggest that evolution of mt genomes is consistent with plant taxonomy but independent among different species.

  10. The mitochondrial genome of Raphanus sativus and gene evolution of cruciferous mitochondrial types.

    Science.gov (United States)

    Chang, Shengxin; Chen, Jianmei; Wang, Yankun; Gu, Bingchao; He, Jianbo; Chu, Pu; Guan, Rongzhan

    2013-03-20

    To explore the mitochondrial genes of the Cruciferae family, the mitochondrial genome of Raphanus sativus (sat) was sequenced and annotated. The circular mitochondrial genome of sat is 239,723 bp and includes 33 protein-coding genes, three rRNA genes and 17 tRNA genes. The mitochondrial genome also contains a pair of large repeat sequences 5.9 kb in length, which may mediate genome reorganization into two sub-genomic circles, with predicted sizes of 124.8 kb and 115.0 kb, respectively. Furthermore, gene evolution of mitochondrial genomes within the Cruciferae family was analyzed using sat mitochondrial type (mitotype), together with six other reported mitotypes. The cruciferous mitochondrial genomes have maintained almost the same set of functional genes. Compared with Cycas taitungensis (a representative gymnosperm), the mitochondrial genomes of the Cruciferae have lost nine protein-coding genes and seven mitochondrial-like tRNA genes, but acquired six chloroplast-like tRNAs. Among the Cruciferae, to maintain the same set of genes that are necessary for mitochondrial function, the exons of the genes have changed at the lowest rates, as indicated by the numbers of single nucleotide polymorphisms. The open reading frames (ORFs) of unknown function in the cruciferous genomes are not conserved. Evolutionary events, such as mutations, genome reorganizations and sequence insertions or deletions (indels), have resulted in the non-conserved ORFs in the cruciferous mitochondrial genomes, which is becoming significantly different among mitotypes. This work represents the first phylogenic explanation of the evolution of genes of known function in the Cruciferae family. It revealed significant variation in ORFs and the causes of such variation.

  11. Phytotoxic cyanamide affects maize (Zea mays) root growth and root tip function: from structure to gene expression.

    Science.gov (United States)

    Soltys, Dorota; Rudzińska-Langwald, Anna; Kurek, Wojciech; Szajko, Katarzyna; Sliwinska, Elwira; Bogatek, Renata; Gniazdowska, Agnieszka

    2014-05-01

    Cyanamide (CA) is a phytotoxic compound produced by four Fabaceae species: hairy vetch, bird vetch, purple vetch and black locust. Its toxicity is due to complex activity that involves the modification of both cellular structures and physiological processes. To date, CA has been investigated mainly in dicot plants. The goal of this study was to investigate the effects of CA in the restriction of the root growth of maize (Zea mays), representing the monocot species. CA (3mM) reduced the number of border cells in the root tips of maize seedlings and degraded their protoplasts. However, CA did not induce any significant changes in the organelle structure of other root cells, apart from increased vacuolization. CA toxicity was also demonstrated by its effect on cell cycle activity, endoreduplication intensity, and modifications of cyclins CycA2, CycD2, and histone HisH3 gene expression. In contrast, the arrangement of microtubules was not altered by CA. Treatment of maize seedlings with CA did not completely arrest mitotic activity, although the frequency of dividing cells was reduced. Furthermore, prolonged CA treatment increased the proportion of endopolyploid cells in the root tip. Cytological malformations were accompanied by an induction of oxidative stress in root cells, which manifested as enhanced accumulation of H2O2. Exposure of maize seedlings to CA resulted in an increased concentration of auxin and stimulated ethylene emission. Taken together, these findings suggested that the inhibition of root growth by CA may be a consequence of stress-induced morphogenic responses.

  12. Differential expression of two bc1 complexes in the strict acidophilic chemolithoautotrophic bacterium Acidithiobacillus ferrooxidans suggests a model for their respective roles in iron or sulfur oxidation.

    Science.gov (United States)

    Bruscella, Patrice; Appia-Ayme, Corinne; Levicán, Gloria; Ratouchniak, Jeanine; Jedlicki, Eugenia; Holmes, David S; Bonnefoy, Violaine

    2007-01-01

    Three strains of the strict acidophilic chemolithoautotrophic Acidithiobacillus ferrooxidans, including the type strain ATCC 23270, contain a petIIABC gene cluster that encodes the three proteins, cytochrome c1, cytochrome b and a Rieske protein, that constitute a bc1 electron-transfer complex. RT-PCR and Northern blotting show that the petIIABC cluster is co-transcribed with cycA, encoding a cytochrome c belonging to the c4 family, sdrA, encoding a putative short-chain dehydrogenase, and hip, encoding a high potential iron-sulfur protein, suggesting that the six genes constitute an operon, termed the petII operon. Previous results indicated that A. ferrooxidans contains a second pet operon, termed the petI operon, which contains a gene cluster that is similarly organized except that it lacks hip. Real-time PCR and Northern blot experiments demonstrate that petI is transcribed mainly in cells grown in medium containing iron, whereas petII is transcribed in cells grown in media containing sulfur or iron. Primer extension experiments revealed possible transcription initiation sites for the petI and petII operons. A model is presented in which petI is proposed to encode the bc1 complex, functioning in the uphill flow of electrons from iron to NAD(P), whereas petII is suggested to be involved in electron transfer from sulfur (or formate) to oxygen (or ferric iron). A. ferrooxidans is the only organism, to date, to exhibit two functional bc1 complexes.

  13. 几种观赏植物根系诱导条件的优化

    Institute of Scientific and Technical Information of China (English)

    陈永华; 王佩; 陈莹; 付伟华

    2015-01-01

    以6种观赏植物仙人掌(Opuntia stricta)、万年青(Rohdea japonica)、虎皮兰(Sansevieria trifasciata)、发财树(Pachira macrocar)、苏铁(Cycas revoluta)、鹅掌柴(Schefflera octophylla)为材料,采用正交试验设计的方法研究遮光方式、曝气时间、营养液类型对诱导根系生长的影响。结果表明:6种观赏植物的根系诱导最佳水平分别为:发财树(清水-不曝气-不遮光),鹅掌柴(清水-曝气10 h/d -全遮光),虎皮兰(霍格兰德配方-曝气5 h/d -不遮光),万年青(霍格兰德配方-曝气5 h/d -遮1/2光),苏铁(霍格兰德配方-曝气5 h/d -遮1/2光),仙人掌(日本园试营养液配方-不曝气-不遮光)。

  14. RNA-seq analysis identifies an intricate regulatory network controlling cluster root development in white lupin

    Science.gov (United States)

    2014-01-01

    Background Highly adapted plant species are able to alter their root architecture to improve nutrient uptake and thrive in environments with limited nutrient supply. Cluster roots (CRs) are specialised structures of dense lateral roots formed by several plant species for the effective mining of nutrient rich soil patches through a combination of increased surface area and exudation of carboxylates. White lupin is becoming a model-species allowing for the discovery of gene networks involved in CR development. A greater understanding of the underlying molecular mechanisms driving these developmental processes is important for the generation of smarter plants for a world with diminishing resources to improve food security. Results RNA-seq analyses for three developmental stages of the CR formed under phosphorus-limited conditions and two of non-cluster roots have been performed for white lupin. In total 133,045,174 high-quality paired-end reads were used for a de novo assembly of the root transcriptome and merged with LAGI01 (Lupinus albus gene index) to generate an improved LAGI02 with 65,097 functionally annotated contigs. This was followed by comparative gene expression analysis. We show marked differences in the transcriptional response across the various cluster root stages to adjust to phosphate limitation by increasing uptake capacity and adjusting metabolic pathways. Several transcription factors such as PLT, SCR, PHB, PHV or AUX/IAA with a known role in the control of meristem activity and developmental processes show an increased expression in the tip of the CR. Genes involved in hormonal responses (PIN, LAX, YUC) and cell cycle control (CYCA/B, CDK) are also differentially expressed. In addition, we identify primary transcripts of miRNAs with established function in the root meristem. Conclusions Our gene expression analysis shows an intricate network of transcription factors and plant hormones controlling CR initiation and formation. In addition

  15. Green Plants in the Red: A Baseline Global Assessment for the IUCN Sampled Red List Index for Plants.

    Directory of Open Access Journals (Sweden)

    Neil A Brummitt

    Full Text Available Plants provide fundamental support systems for life on Earth and are the basis for all terrestrial ecosystems; a decline in plant diversity will be detrimental to all other groups of organisms including humans. Decline in plant diversity has been hard to quantify, due to the huge numbers of known and yet to be discovered species and the lack of an adequate baseline assessment of extinction risk against which to track changes. The biodiversity of many remote parts of the world remains poorly known, and the rate of new assessments of extinction risk for individual plant species approximates the rate at which new plant species are described. Thus the question 'How threatened are plants?' is still very difficult to answer accurately. While completing assessments for each species of plant remains a distant prospect, by assessing a randomly selected sample of species the Sampled Red List Index for Plants gives, for the first time, an accurate view of how threatened plants are across the world. It represents the first key phase of ongoing efforts to monitor the status of the world's plants. More than 20% of plant species assessed are threatened with extinction, and the habitat with the most threatened species is overwhelmingly tropical rain forest, where the greatest threat to plants is anthropogenic habitat conversion, for arable and livestock agriculture, and harvesting of natural resources. Gymnosperms (e.g. conifers and cycads are the most threatened group, while a third of plant species included in this study have yet to receive an assessment or are so poorly known that we cannot yet ascertain whether they are threatened or not. This study provides a baseline assessment from which trends in the status of plant biodiversity can be measured and periodically reassessed.

  16. Green Plants in the Red: A Baseline Global Assessment for the IUCN Sampled Red List Index for Plants.

    Science.gov (United States)

    Brummitt, Neil A; Bachman, Steven P; Griffiths-Lee, Janine; Lutz, Maiko; Moat, Justin F; Farjon, Aljos; Donaldson, John S; Hilton-Taylor, Craig; Meagher, Thomas R; Albuquerque, Sara; Aletrari, Elina; Andrews, A Kei; Atchison, Guy; Baloch, Elisabeth; Barlozzini, Barbara; Brunazzi, Alice; Carretero, Julia; Celesti, Marco; Chadburn, Helen; Cianfoni, Eduardo; Cockel, Chris; Coldwell, Vanessa; Concetti, Benedetta; Contu, Sara; Crook, Vicki; Dyson, Philippa; Gardiner, Lauren; Ghanim, Nadia; Greene, Hannah; Groom, Alice; Harker, Ruth; Hopkins, Della; Khela, Sonia; Lakeman-Fraser, Poppy; Lindon, Heather; Lockwood, Helen; Loftus, Christine; Lombrici, Debora; Lopez-Poveda, Lucia; Lyon, James; Malcolm-Tompkins, Patricia; McGregor, Kirsty; Moreno, Laura; Murray, Linda; Nazar, Keara; Power, Emily; Quiton Tuijtelaars, Mireya; Salter, Ruth; Segrott, Robert; Thacker, Hannah; Thomas, Leighton J; Tingvoll, Sarah; Watkinson, Gemma; Wojtaszekova, Katerina; Nic Lughadha, Eimear M

    2015-01-01

    Plants provide fundamental support systems for life on Earth and are the basis for all terrestrial ecosystems; a decline in plant diversity will be detrimental to all other groups of organisms including humans. Decline in plant diversity has been hard to quantify, due to the huge numbers of known and yet to be discovered species and the lack of an adequate baseline assessment of extinction risk against which to track changes. The biodiversity of many remote parts of the world remains poorly known, and the rate of new assessments of extinction risk for individual plant species approximates the rate at which new plant species are described. Thus the question 'How threatened are plants?' is still very difficult to answer accurately. While completing assessments for each species of plant remains a distant prospect, by assessing a randomly selected sample of species the Sampled Red List Index for Plants gives, for the first time, an accurate view of how threatened plants are across the world. It represents the first key phase of ongoing efforts to monitor the status of the world's plants. More than 20% of plant species assessed are threatened with extinction, and the habitat with the most threatened species is overwhelmingly tropical rain forest, where the greatest threat to plants is anthropogenic habitat conversion, for arable and livestock agriculture, and harvesting of natural resources. Gymnosperms (e.g. conifers and cycads) are the most threatened group, while a third of plant species included in this study have yet to receive an assessment or are so poorly known that we cannot yet ascertain whether they are threatened or not. This study provides a baseline assessment from which trends in the status of plant biodiversity can be measured and periodically reassessed.

  17. Palynological records of the Early Permian icehouse-greenhouse transition (Ecca Group, South Africa)

    Science.gov (United States)

    Götz, Annette E.; Ruckwied, Katrin

    2013-04-01

    The Permian coal-bearing formations of the South African Karoo Basin play a crucial role in the study and interpretation of Gondwana's climate history and biodiversity in this time of major global changes in terrestrial and marine ecosystems. Here, we report on new palynological data from the No. 2 coal seam of the northern Witbank coal field, documenting the switch from Icehouse to Greenhouse conditions in the Early Permian (Lower Ecca Group). The studied postglacial fluvio-deltaic deposits of a highly proximal setting comprise coarse-grained to pebbly sandstones, partially with an abrupt upward transition into fine-grained sediments and coal, trough cross-stratified medium- to coarse-grained sandstones, and horizontally laminated fine- to medium-grained sandstones and siltstones. The sedimentary organic matter content clearly documents stratal changes in the palynomorph assemblage and variations in the amount and in the type, size and shape of plant debris. Generally, palynofacies is characterized by a high amount of opaque phytoclasts. Amorphous organic matter is characteristic of laminated siltstones and coals. The palynological record indicates a cold climate, fern wetland community, characteristic of lowland alluvial plains, and an upland conifer community in the lower part of the coal seam. Up section, these communities are replaced by a cool-temperate cycad-like lowland vegetation and gymnospermous upland flora. Ongoing studies focus on the cyclic architecture of the coal seam, applying palynofacies analysis as high-resolution correlation tool with respect to decipher signatures of prominent climate amelioration on basin-wide, intercontinental and intra-Gondwanic scales.

  18. Phylogeny of seed plants based on all three genomic compartments: extant gymnosperms are monophyletic and Gnetales' closest relatives are conifers.

    Science.gov (United States)

    Bowe, L M; Coat, G; dePamphilis, C W

    2000-04-11

    Efforts to resolve Darwin's "abominable mystery"-the origin of angiosperms-have led to the conclusion that Gnetales and various fossil groups are sister to angiosperms, forming the "anthophytes." Morphological homologies, however, are difficult to interpret, and molecular data have not provided clear resolution of relationships among major groups of seed plants. We introduce two sequence data sets from slowly evolving mitochondrial genes, cox1 and atpA, which unambiguously reject the anthophyte hypothesis, favoring instead a close relationship between Gnetales and conifers. Parsimony- and likelihood-based analyses of plastid rbcL and nuclear 18S rDNA alone and with cox1 and atpA also strongly support a gnetophyte-conifer grouping. Surprisingly, three of four genes (all but nuclear rDNA) and combined three-genome analyses also suggest or strongly support Gnetales as derived conifers, sister to Pinaceae. Analyses with outgroups screened to avoid long branches consistently identify all gymnosperms as a monophyletic sister group to angiosperms. Combined three- and four-gene rooted analyses resolve the branching order for the remaining major groups-cycads separate from other gymnosperms first, followed by Ginkgo and then (Gnetales + Pinaceae) sister to a monophyletic group with all other conifer families. The molecular phylogeny strongly conflicts with current interpretations of seed plant morphology, and implies that many similarities between gnetophytes and angiosperms, such as "flower-like" reproductive structures and double fertilization, were independently derived, whereas other characters could emerge as synapomorphies for an expanded conifer group including Gnetales. An initial angiosperm-gymnosperm split implies a long stem lineage preceding the explosive Mesozoic radiation of flowering plants and suggests that angiosperm origins and homologies should be sought among extinct seed plant groups.

  19. Cell size, genome size and the dominance of Angiosperms

    Science.gov (United States)

    Simonin, K. A.; Roddy, A. B.

    2016-12-01

    Angiosperms are capable of maintaining the highest rates of photosynthetic gas exchange of all land plants. High rates of photosynthesis depends mechanistically both on efficiently transporting water to the sites of evaporation in the leaf and on regulating the loss of that water to the atmosphere as CO2 diffuses into the leaf. Angiosperm leaves are unique in their ability to sustain high fluxes of liquid and vapor phase water transport due to high vein densities and numerous, small stomata. Despite the ubiquity of studies characterizing the anatomical and physiological adaptations that enable angiosperms to maintain high rates of photosynthesis, the underlying mechanism explaining why they have been able to develop such high leaf vein densities, and such small and abundant stomata, is still incomplete. Here we ask whether the scaling of genome size and cell size places a fundamental constraint on the photosynthetic metabolism of land plants, and whether genome downsizing among the angiosperms directly contributed to their greater potential and realized primary productivity relative to the other major groups of terrestrial plants. Using previously published data we show that a single relationship can predict guard cell size from genome size across the major groups of terrestrial land plants (e.g. angiosperms, conifers, cycads and ferns). Similarly, a strong positive correlation exists between genome size and both stomatal density and vein density that together ultimately constrains maximum potential (gs, max) and operational stomatal conductance (gs, op). Further the difference in the slopes describing the covariation between genome size and both gs, max and gs, op suggests that genome downsizing brings gs, op closer to gs, max. Taken together the data presented here suggests that the smaller genomes of angiosperms allow their final cell sizes to vary more widely and respond more directly to environmental conditions and in doing so bring operational photosynthetic

  20. Contrasting Rates of Molecular Evolution and Patterns of Selection among Gymnosperms and Flowering Plants

    Science.gov (United States)

    Li, Zhen; Van de Peer, Yves; Ingvarsson, Pär K.

    2017-01-01

    Abstract The majority of variation in rates of molecular evolution among seed plants remains both unexplored and unexplained. Although some attention has been given to flowering plants, reports of molecular evolutionary rates for their sister plant clade (gymnosperms) are scarce, and to our knowledge differences in molecular evolution among seed plant clades have never been tested in a phylogenetic framework. Angiosperms and gymnosperms differ in a number of features, of which contrasting reproductive biology, life spans, and population sizes are the most prominent. The highly conserved morphology of gymnosperms evidenced by similarity of extant species to fossil records and the high levels of macrosynteny at the genomic level have led scientists to believe that gymnosperms are slow-evolving plants, although some studies have offered contradictory results. Here, we used 31,968 nucleotide sites obtained from orthologous genes across a wide taxonomic sampling that includes representatives of most conifers, cycads, ginkgo, and many angiosperms with a sequenced genome. Our results suggest that angiosperms and gymnosperms differ considerably in their rates of molecular evolution per unit time, with gymnosperm rates being, on average, seven times lower than angiosperm species. Longer generation times and larger genome sizes are some of the factors explaining the slow rates of molecular evolution found in gymnosperms. In contrast to their slow rates of molecular evolution, gymnosperms possess higher substitution rate ratios than angiosperm taxa. Finally, our study suggests stronger and more efficient purifying and diversifying selection in gymnosperm than in angiosperm species, probably in relation to larger effective population sizes. PMID:28333233

  1. 内蒙古锡林浩特侏罗纪红旗组孢粉化石的发现及其古气候意义%Discovery of Sporopollen Fossils of Jurassic Hongqi Formation in Xilinhot, Inner Mongolia, and Its Paleoclimate Significance

    Institute of Scientific and Technical Information of China (English)

    杨兵; 张雄华; 葛梦春; 潘文静

    2013-01-01

    Abundant sporopollen fossils, including 26 genera and 39 species are found for the first time in the lower part of Jurassic Hongqi Formation in Xilinhot Coal field, Inner Mongolia, According to the characteristics and stratigraphic distribution of the sporopollen fossils, the age of Dictyophyllidites-Cyathid-ites-Classopollis assemblage belongs to the late of Early Jurassic. The palynological assemblage is correspondent to that of some regions in North China, Northeast China and Northwest China. Furthermore, based on the analysis of composition of sporopollen, it is suggested that the ancient plants are mainly chei-rolepidiaceae, conifers, cycad, cyatheaceae, dipteridaceae during Early Jurassic. Paleovegetation types are coniferous-leaved and broad-leaved mixed forests, indicating that the paleoclimate was from being semi-dry to semi-humid subtropical environment during this period.%内蒙古锡林浩特煤矿侏罗纪红旗组下部首次发现了大量孢粉化石,经鉴定计有孢粉化石26属39种.根据孢粉化石组合特征及地层分布将其命名为Dictyoph yllidites-C yathidites-Classopollis组合,时代属早侏罗世晚期,与华北区、东北区及西北区同时期地层中的孢粉组合能很好地对应.此外,通过孢粉化石组分研究,确定该区早侏罗世古植物主要为掌鳞杉科、松柏类、苏铁科、桫椤科、双扇蕨科等,古植被类主要为针、阔混交林,进而推断该期为亚热带半干旱—半湿润、偏湿润的古气候.

  2. The Early Jurassic sporo-pollen assemblages and paleoclimate of the central depression in the Junggar Basin%准噶尔盆地中央坳陷早侏罗世孢粉组合与古气候

    Institute of Scientific and Technical Information of China (English)

    刘春雷; 尹凤娟; 樊婷婷

    2013-01-01

    通过显微镜观察鉴定了准噶尔盆地中央坳陷重点探井——征1井早侏罗世孢粉化石.认为准噶尔盆地征沙村地区早侏罗世孢粉组合划分为两个:产于八道湾组的Cyathidites-Cycadopites 孢粉组合和产于三工河组的Cyathidites-Classopollis孢粉组合.通过研究孢粉组分和母本植物的亲缘关系,得出准噶尔盆地中央坳陷早侏罗世植被主要由草本的真蕨植物和乔木、灌木的松柏类及银杏、苏铁类等组成,所反映古气候应属亚热带气候.%According to palynological assemblages from the analysis of sporo-pollen sample collected in drilling hole, sporo-pollen assemblages of the Zheng 1 well in the central depression in the Junggar Basin were recognized by observing and identifying under microscope. The Lower Jurassic in the Zhengshacun of Juggar Basin can be divided into two sporo-pollen assemblages: the Cyathidites-Cycadopites assemblage from the Badaowan Formation and Cyathidites-Classopollis assemblage from Sangonghe Formation. By researching the kinship between the sporo-pollen assemblages and vegetation types, it is concluded that the Early Jurassic consists mainly of herbaceous Filicinae and arbor, Coniferales and ginkgo belonged to bush and cycad,and indicates that the paleoclimate belongs to subtropical climate.

  3. A comparative study on three analytical methods for the determination of the neurotoxin BMAA in cyanobacteria.

    Directory of Open Access Journals (Sweden)

    Elisabeth J Faassen

    Full Text Available The cyanobacterial neurotoxin β-N-methylamino-L-alanine (BMAA has been considered a serious health threat because of its putative role in multiple neurodegenerative diseases. First reports on BMAA concentrations in cyanobacteria were alarming: nearly all cyanobacteria were assumed to contain high BMAA concentrations, implying ubiquitous exposure. Recent studies however question this presence of high BMAA concentrations in cyanobacteria. To assess the real risk of BMAA to human health, this discrepancy must be resolved. We therefore tested whether the differences found could be caused by the analytical methods used in different studies. Eight cyanobacterial samples and two control samples were analyzed by three commonly used methods: HPLC-FLD analysis and LC-MS/MS analysis of both derivatized and underivatized samples. In line with published results, HPLC-FLD detected relatively high BMAA concentrations in some cyanobacterial samples, while both LC-MS/MS methods only detected BMAA in the positive control (cycad seed sarcotesta. Because we could eliminate the use of different samples and treatments as causal factors, we demonstrate that the observed differences were caused by the analytical methods. We conclude that HPLC-FLD overestimated BMAA concentrations in some cyanobacterial samples due to its low selectivity and propose that BMAA might be present in (some cyanobacteria, but in the low µg/g or ng/g range instead of the high µg/g range as sometimes reported before. We therefore recommend to use only selective and sensitive analytical methods like LC-MS/MS for BMAA analysis. Although possibly present in low concentrations in cyanobacteria, BMAA can still form a health risk. Recent evidence on BMAA accumulation in aquatic food chains suggests human exposure through consumption of fish and shellfish which expectedly exceeds exposure through cyanobacteria.

  4. Green Plants in the Red: A Baseline Global Assessment for the IUCN Sampled Red List Index for Plants

    Science.gov (United States)

    Griffiths-Lee, Janine; Lutz, Maiko; Moat, Justin F.; Farjon, Aljos; Donaldson, John S.; Hilton-Taylor, Craig; Meagher, Thomas R.; Albuquerque, Sara; Aletrari, Elina; Andrews, A. Kei; Atchison, Guy; Baloch, Elisabeth; Barlozzini, Barbara; Brunazzi, Alice; Carretero, Julia; Celesti, Marco; Chadburn, Helen; Cianfoni, Eduardo; Cockel, Chris; Coldwell, Vanessa; Concetti, Benedetta; Contu, Sara; Crook, Vicki; Dyson, Philippa; Gardiner, Lauren; Ghanim, Nadia; Greene, Hannah; Groom, Alice; Harker, Ruth; Hopkins, Della; Khela, Sonia; Lakeman-Fraser, Poppy; Lindon, Heather; Lockwood, Helen; Loftus, Christine; Lombrici, Debora; Lopez-Poveda, Lucia; Lyon, James; Malcolm-Tompkins, Patricia; McGregor, Kirsty; Moreno, Laura; Murray, Linda; Nazar, Keara; Power, Emily; Quiton Tuijtelaars, Mireya; Salter, Ruth; Segrott, Robert; Thacker, Hannah; Thomas, Leighton J.; Tingvoll, Sarah; Watkinson, Gemma; Wojtaszekova, Katerina; Nic Lughadha, Eimear M.

    2015-01-01

    Plants provide fundamental support systems for life on Earth and are the basis for all terrestrial ecosystems; a decline in plant diversity will be detrimental to all other groups of organisms including humans. Decline in plant diversity has been hard to quantify, due to the huge numbers of known and yet to be discovered species and the lack of an adequate baseline assessment of extinction risk against which to track changes. The biodiversity of many remote parts of the world remains poorly known, and the rate of new assessments of extinction risk for individual plant species approximates the rate at which new plant species are described. Thus the question ‘How threatened are plants?’ is still very difficult to answer accurately. While completing assessments for each species of plant remains a distant prospect, by assessing a randomly selected sample of species the Sampled Red List Index for Plants gives, for the first time, an accurate view of how threatened plants are across the world. It represents the first key phase of ongoing efforts to monitor the status of the world’s plants. More than 20% of plant species assessed are threatened with extinction, and the habitat with the most threatened species is overwhelmingly tropical rain forest, where the greatest threat to plants is anthropogenic habitat conversion, for arable and livestock agriculture, and harvesting of natural resources. Gymnosperms (e.g. conifers and cycads) are the most threatened group, while a third of plant species included in this study have yet to receive an assessment or are so poorly known that we cannot yet ascertain whether they are threatened or not. This study provides a baseline assessment from which trends in the status of plant biodiversity can be measured and periodically reassessed. PMID:26252495

  5. Modeling Spatial Distribution of a Rare and Endangered Plant Species (Brainea insignis) in Central Taiwan

    Science.gov (United States)

    Wang, W.-C.; Lo, N.-J.; Chang, W.-I.; Huang, K.-Y.

    2012-07-01

    With an increase in the rate of species extinction, we should choose right methods that are sustainable on the basis of appropriate science and human needs to conserve ecosystems and rare species. Species distribution modeling (SDM) uses 3S technology and statistics and becomes increasingly important in ecology. Brainea insignis (cycad-fern, CF) has been categorized a rare, endangered plant species, and thus was chosen as a target for the study. Five sampling schemes were created with different combinations of CF samples collected from three sites in Huisun forest station and one site, 10 km farther north from Huisun. Four models, MAXENT, GARP, generalized linear models (GLM), and discriminant analysis (DA), were developed based on topographic variables, and were evaluated by five sampling schemes. The accuracy of MAXENT was the highest, followed by GLM and GARP, and DA was the lowest. More importantly, they can identify the potential habitat less than 10% of the study area in the first round of SDM, thereby prioritizing either the field-survey area where microclimatic, edaphic or biotic data can be collected for refining predictions of potential habitat in the later rounds of SDM or search areas for new population discovery. However, it was shown unlikely to extend spatial patterns of CFs from one area to another with a big separation or to a larger area by predictive models merely based on topographic variables. Follow-up studies will attempt to incorporate proxy indicators that can be extracted from hyperspectral images or LIDAR DEM and substitute for direct parameters to make predictive models applicable on a broader scale.

  6. A system of recurrent neural networks for modularising, parameterising and dynamic analysis of cell signalling networks.

    Science.gov (United States)

    Samarasinghe, S; Ling, H

    2017-02-04

    In this paper, we show how to extend our previously proposed novel continuous time Recurrent Neural Networks (RNN) approach that retains the advantage of continuous dynamics offered by Ordinary Differential Equations (ODE) while enabling parameter estimation through adaptation, to larger signalling networks using a modular approach. Specifically, the signalling network is decomposed into several sub-models based on important temporal events in the network. Each sub-model is represented by the proposed RNN and trained using data generated from the corresponding ODE model. Trained sub-models are assembled into a whole system RNN which is then subjected to systems dynamics and sensitivity analyses. The concept is illustrated by application to G1/S transition in cell cycle using Iwamoto et al. (2008) ODE model. We decomposed the G1/S network into 3 sub-models: (i) E2F transcription factor release; (ii) E2F and CycE positive feedback loop for elevating cyclin levels; and (iii) E2F and CycA negative feedback to degrade E2F. The trained sub-models accurately represented system dynamics and parameters were in good agreement with the ODE model. The whole system RNN however revealed couple of parameters contributing to compounding errors due to feedback and required refinement to sub-model 2. These related to the reversible reaction between CycE/CDK2 and p27, its inhibitor. The revised whole system RNN model very accurately matched dynamics of the ODE system. Local sensitivity analysis of the whole system model further revealed the most dominant influence of the above two parameters in perturbing G1/S transition, giving support to a recent hypothesis that the release of inhibitor p27 from Cyc/CDK complex triggers cell cycle stage transition. To make the model useful in a practical setting, we modified each RNN sub-model with a time relay switch to facilitate larger interval input data (≈20min) (original model used data for 30s or less) and retrained them that produced

  7. In vitro Embryogenesis Derived from Shoot Tips in Mass Propagation of Two Selected-Clones of Phalaenopsis

    Directory of Open Access Journals (Sweden)

    Budi WINARTO

    2016-09-01

    Full Text Available Phalaenopsis is of high economic value and market demand in Indonesia; however, orchid products are mostly imported from other countries. ‘Kristina Dwi’ (KD 69.274 and ‘Dedeh’ (D 802.28 are two selected clones with high potential utilized and developed commercially. To support their commercialization, a reliable in vitro propagation protocol is essential. In the current study, an in vitro mass propagation protocol for KD 69.274 and D 802.28 clones was successfully established using shoot tips as explant sources. A high number of embryos, up to 8.2 embryos per explant, with 58.5% explant regeneration, and 3.5 regenerated-explants in average were regenerated from shoot tips of KD 69.274 clone cultured on half-strength Murashige and Skoog (MS medium, with full strength micro, Fe-chellate and vitamin containing 0.5 mg/L thidiazuruon (TDZ and 0.25 mg/L N6-benzyladenine (BA. The initial embryos were proliferated by culturing embryos individually on half-strength MS medium with 0.13 mg/L TDZ and 0.25 mg/L BA and resulted in high embryo regeneration up to 91.4%, with 10.2 embryos per explant and no embryo browning. The embryos were multiplied under periodical subcultures of 3 months each, resulting in gradual increasing number of embryos from the first subculture till the fifth subculture, with 23.6 embryos produced, then declined afterward. The embryos were easily germinated on half-strength MS medium with full strength of vitamin and hormone free, with 73.9% embryo germination and 14.9 germinated embryos. Healthy plantlets were stimulated on the same medium with 2 g/L activated charcoal (AC and successfully acclimatized on Cycas rumphii bulk, with 88.3% survival plantlets. Finally, it can be summarized that a new in vitro mass propagation protocol, as new alternative choice for Phalaenopsis propagation, was successfully established. Full Text: PDF DOI: http://dx.doi.org/

  8. Seeking environmental causes of neurodegenerative disease and envisioning primary prevention.

    Science.gov (United States)

    Spencer, Peter S; Palmer, Valerie S; Kisby, Glen E

    2016-09-01

    Pathological changes of the aging brain are expressed in a range of neurodegenerative disorders that will impact increasing numbers of people across the globe. Research on the causes of these disorders has focused heavily on genetics, and strategies for prevention envision drug-induced slowing or arresting disease advance before its clinical appearance. We discuss a strategic shift that seeks to identify the environmental causes or contributions to neurodegeneration, and the vision of primary disease prevention by removing or controlling exposure to culpable agents. The plausibility of this approach is illustrated by the prototypical neurodegenerative disease amyotrophic lateral sclerosis and parkinsonism-dementia complex (ALS-PDC). This often-familial long-latency disease, once thought to be an inherited genetic disorder but now known to have a predominant or exclusive environmental origin, is in the process of disappearing from the three heavily affected populations, namely Chamorros of Guam and Rota, Japanese residents of Kii Peninsula, Honshu, and Auyu and Jaqai linguistic groups on the island of New Guinea in West Papua, Indonesia. Exposure via traditional food and/or medicine (the only common exposure in all three geographic isolates) to one or more neurotoxins in seed of cycad plants is the most plausible if yet unproven etiology. Neurotoxin dosage and/or subject age at exposure might explain the stratified epidemic of neurodegenerative disease on Guam in which high-incidence ALS peaked and declined before that of PD, only to be replaced today by a dementing disorder comparable to Alzheimer's disease. Exposure to the Guam environment is also linked to the delayed development of ALS among a subset of Chamorro and non-Chamorro Gulf War/Era veterans, a summary of which is reported here for the first time. Lessons learned from this study and from 65 years of research on ALS-PDC include the exceptional value of initial, field-based informal investigation of

  9. Carbon isotope alteration during the thermal maturation of non-flowering plant species representative of those found within the geological record.

    Science.gov (United States)

    Smith, Andrew C; Kendrick, Christopher P; Moss-Hayes, Vicky L; Vane, Christopher H; Leng, Melanie J

    2017-01-15

    The carbon isotope (δ(13) C value) composition of fossil plant material is routinely used as a proxy of past climate and environment change. However, palaeoclimate interpretation requires assumptions about the stability of δ(13) C values in plant material during its decomposition and incorporation into sediments. Previous work on modern angiosperm species shows δ(13) C changes of several per mille during simulated decomposition experiments. However, no such tests have been undertaken on non-flowering plants, which are found extensively within the geological record. These plants have distinctly different cellulose-to-lignin ratios from those of their angiosperm counterparts, potentially creating hitherto unknown variations in the original to fossil δ(13) C signatures. To test the extent of δ(13) C change during decomposition we have subjected a number of plants, representing more basal, non-flowering plant lineages (cycads, ferns, horsetails and dawn redwood), to artificial decay using a hydrothermal maturation technique at two temperatures over periods of up to 273 hours. Subsamples were extracted every 12-16 hours and analysed for their δ(13) C and %C values using a Carlo Erba 1500 elemental analyser, and VG TripleTrap and Optima mass spectrometers. The %C values increased for all samples through the maturation process at both temperatures with the largest increases observed within the first 24 hours. Decreases in δ(13) C values were observed for all plants at 300°C and for two of the species at the lower temperature (200°C). The maximum shift in the δ(13) C value related to experimental decomposition was -0.90‰ (horsetail), indicating a preferential loss of (13) C during thermal maturation. The reduction in the δ(13) C value potentially suggests a preferential loss of isotopically heavier cellulose in relation to the isotopically lighter lignin component during maturation. The isotopic offset observed here (<0.9‰) means that palaeoclimatic

  10. Southern high-latitude terrestrial climate change during the Palaeocene-Eocene derived from a marine pollen record (ODP Site 1172, East Tasman Plateau)

    Science.gov (United States)

    Contreras, L.; Pross, J.; Bijl, P. K.; O'Hara, R. B.; Raine, J. I.; Sluijs, A.; Brinkhuis, H.

    2014-07-01

    Reconstructing the early Palaeogene climate dynamics of terrestrial settings in the high southern latitudes is important to assess the role of high-latitude physical and biogeochemical processes in the global climate system. However, whereas a number of high-quality Palaeogene climate records has become available for the marine realm of the high southern latitudes over the recent past, the long-term evolution of coeval terrestrial climates and ecosystems is yet poorly known. We here explore the climate and vegetation dynamics on Tasmania from the middle Palaeocene to the early Eocene (60.7-54.2 Ma) based on a sporomorph record from Ocean Drilling Program (ODP) Site 1172 on the East Tasman Plateau. Our results show that three distinctly different vegetation types thrived on Tasmania under a high-precipitation regime during the middle Palaeocene to early Eocene, with each type representing different temperature conditions: (i) warm-temperate forests dominated by gymnosperms that were dominant during the middle and late Palaeocene (excluding the middle/late Palaeocene transition); (ii) cool-temperate forests dominated by southern beech (Nothofagus) and araucarians that transiently prevailed across the middle/late Palaeocene transition interval (~ 59.5 to ~ 59.0 Ma); and (iii) paratropical forests rich in ferns that were established during and in the wake of the Palaeocene-Eocene Thermal Maximum (PETM). The transient establishment of cool-temperate forests lacking any frost-sensitive elements (i.e. palms and cycads) across the middle/late Palaeocene transition interval indicates markedly cooler conditions, with the occurrence of frosts in winter, on Tasmania during that time. The integration of our sporomorph data with previously published TEX86-based sea-surface temperatures from ODP Site 1172 documents that the vegetation dynamics on Tasmania were closely linked with the temperature evolution in the Tasman sector of the Southwest Pacific region. Moreover, the

  11. Southern high-latitude terrestrial climate change during the Paleocene-Eocene derived from a marine pollen record (ODP Site 1172, East Tasman Plateau)

    Science.gov (United States)

    Contreras, L.; Pross, J.; Bijl, P. K.; O'Hara, R. B.; Raine, J. I.; Sluijs, A.; Brinkhuis, H.

    2014-01-01

    Reconstructing the early Paleogene climate dynamics of terrestrial settings in the high southern latitudes is important to assess the role of high-latitude physical and biogeochemical processes in the global climate system. However, whereas a number of high-quality Paleogene climate records has become available for the marine realm of the high southern latitudes over the recent past, the long-term evolution of coeval terrestrial climates and ecosystems is yet poorly known. We here explore the climate and vegetation dynamics on Tasmania from the middle Paleocene to the early Eocene (60.7-54.2 Ma) based on a sporomorph record from Ocean Drilling Program (ODP) Site 1172 on the East Tasman Plateau. Our results show that three distinctly different vegetation types thrived on Tasmania under a high-precipitation regime during the middle Paleocene to early Eocene, with each type representing different temperature conditions: (i) warm-temperate forests dominated by gymnosperms that were dominant during the middle and late Paleocene; (ii) cool-temperate forests dominated by southern beech (Nothofagus) and araucarians across the middle/late Paleocene transition interval (~59.5 to ~59.0 Ma); and (iii) paratropical forests rich in ferns that were established during and in the wake of the Paleocene-Eocene Thermal Maximum (PETM). The transient establishment of cool-temperate forests lacking any frost-sensitive elements (i.e., palms and cycads) across the middle/late Paleocene transition interval indicates markedly cooler conditions, with the occurrence of frosts in winter, on Tasmania during that time. The integration of our sporomorph data with previously published TEX86-based sea-surface temperatures from ODP Site 1172 documents that the vegetation dynamics on Tasmania were closely linked with the temperature evolution in the Tasman sector of the Southwest Pacific region. Moreover, the comparison of our season-specific climate estimates for the sporomorph assemblages from ODP

  12. Nodularin, a cyanobacterial toxin, is synthesized in planta by symbiotic Nostoc sp.

    Science.gov (United States)

    Gehringer, Michelle M; Adler, Lewis; Roberts, Alexandra A; Moffitt, Michelle C; Mihali, Troco K; Mills, Toby J T; Fieker, Claus; Neilan, Brett A

    2012-10-01

    The nitrogen-fixing bacterium, Nostoc, is a commonly occurring cyanobacterium often found in symbiotic associations. We investigated the potential of cycad cyanobacterial endosymbionts to synthesize microcystin/nodularin. Endosymbiont DNA was screened for the aminotransferase domain of the toxin biosynthesis gene clusters. Five endosymbionts carrying the gene were screened for bioactivity. Extracts of two isolates inhibited protein phosphatase 2A and were further analyzed using electrospray ionization mass spectrometry (ESI-MS)/MS. Nostoc sp. 'Macrozamia riedlei 65.1' and Nostoc sp. 'Macrozamia serpentina 73.1' both contained nodularin. High performance liquid chromatography (HPLC) HESI-MS/MS analysis confirmed the presence of nodularin at 9.55±2.4 ng μg-1 chlorophyll a in Nostoc sp. 'Macrozamia riedlei 65.1' and 12.5±8.4 ng μg-1 Chl a in Nostoc sp. 'Macrozamia serpentina 73.1' extracts. Further scans indicated the presence of the rare isoform [L-Har(2)] nodularin, which contains L-homoarginine instead of L-arginine. Nodularin was also present at 1.34±0.74 ng ml(-1) (approximately 3 pmol per g plant ww) in the methanol root extracts of M. riedlei MZ65, while the presence of [L-Har(2)] nodularin in the roots of M. serpentina MZ73 was suggested by HPLC HESI-MS/MS analysis. The ndaA-B and ndaF genomic regions were sequenced to confirm the presence of the hybrid polyketide/non-ribosomal gene cluster. A seven amino-acid insertion into the NdaA-C1 domain of N. spumigena NSOR10 protein was observed in all endosymbiont-derived sequences, suggesting the transfer of the nda cluster from N. spumigena to terrestrial Nostoc species. This study demonstrates the synthesis of nodularin and [L-Har(2)] nodularin in a non-Nodularia species and the production of cyanobacterial hepatotoxin by a symbiont in planta.

  13. Multistate characters and diet shifts: evolution of Erotylidae (Coleoptera).

    Science.gov (United States)

    Leschen, Richard A B; Buckley, Thomas R

    2007-02-01

    macrofungi. Cycad feeding is scattered in more deeply diverged taxa and may have preceded the evolution of angiosperm feeding in some groups. Preliminary analysis of diet mapped onto higher beetle phylogenies suggests that about half of the major Coleoptera lineages may have had fungus-feeding ancestors. We discuss the roles of stochastic models and prior distributions of the reconstruction of ancestral character states in the context of the current data.

  14. Floral responses to the Late Paleozoic deglaciation

    Science.gov (United States)

    Looy, C. V.; DiMichele, W. A.

    2011-12-01

    The current human-induced thawing of ice house Earth prompts the careful examination of similar earlier events and their biotic consequences. The most recent full transition from a cool earth to a warm world took place in the Early to Middle Permian. Against a background of global warming, plant communities were affected globally resulting in migrations, extinctions and changed evolutionary patterns as a response to the environmental changes. The collapse of the southern hemisphere ice-sheets resulted in significant changes, not just at higher latitudes, but also in the tropics where the rainfall regime changed from seasonally dry to seasonally wet. In the Early Permian tropics - in areas where net sedimentation facilitates fossilization, to be more specific - vegetation rich in walchian conifers began to replace the spore plants and seed ferns that previously dominated the Late Pennsylvanian wetlands. The replacing drier floras probably lived in the basinal lowlands as well, but episodically at the drier times of climate cycles. New finds within the tropics of latest Early to Middle Permian-age, in particular from north-central Texas, indicate the existence of floras which were adapted to even more extended periods of drought. These were populated by the more derived voltzian conifers and other seed plants, such as cycads. Surprisingly, the clades in these floras were until recently only known from the tens-of-millions-of-years younger Late Permian and Early Mesozoic, where they were the dominant forms. These occurrences demonstrate that even more derived groups were already in existence and well differentiated by the Early Permian, outside the window of preservation. This pattern of change in conifers and their communities from north-central Texas is unique in that it represents the best documented record in the Phanerozoic of terrestrial ecosystem response to a change from a global cool-mode to warm-mode Earth. Conifers serve as "marker plants" for the

  15. Southern high-latitude terrestrial climate change during the Paleocene–Eocene derived from a marine pollen record (ODP Site 1172, East Tasman Plateau

    Directory of Open Access Journals (Sweden)

    L. Contreras

    2014-01-01

    Full Text Available Reconstructing the early Paleogene climate dynamics of terrestrial settings in the high southern latitudes is important to assess the role of high-latitude physical and biogeochemical processes in the global climate system. However, whereas a number of high-quality Paleogene climate records has become available for the marine realm of the high southern latitudes over the recent past, the long-term evolution of coeval terrestrial climates and ecosystems is yet poorly known. We here explore the climate and vegetation dynamics on Tasmania from the middle Paleocene to the early Eocene (60.7–54.2 Ma based on a sporomorph record from Ocean Drilling Program (ODP Site 1172 on the East Tasman Plateau. Our results show that three distinctly different vegetation types thrived on Tasmania under a high-precipitation regime during the middle Paleocene to early Eocene, with each type representing different temperature conditions: (i warm-temperate forests dominated by gymnosperms that were dominant during the middle and late Paleocene; (ii cool-temperate forests dominated by southern beech (Nothofagus and araucarians across the middle/late Paleocene transition interval (~59.5 to ~59.0 Ma; and (iii paratropical forests rich in ferns that were established during and in the wake of the Paleocene–Eocene Thermal Maximum (PETM. The transient establishment of cool-temperate forests lacking any frost-sensitive elements (i.e., palms and cycads across the middle/late Paleocene transition interval indicates markedly cooler conditions, with the occurrence of frosts in winter, on Tasmania during that time. The integration of our sporomorph data with previously published TEX86-based sea-surface temperatures from ODP Site 1172 documents that the vegetation dynamics on Tasmania were closely linked with the temperature evolution in the Tasman sector of the Southwest Pacific region. Moreover, the comparison of our season-specific climate estimates for the sporomorph

  16. 蓝藻菌/β-N-甲氨基-L-丙氨酸学说在肌萎缩侧索硬化症及其他神经变性病致病机制中的研究进展%The Cyanobacteria/β-N-methylamino-L-alanine Hypothesis of the Pathogenesis of Amyotrophic Lateral Sclerosis and Other Neurodegenerative Diseases

    Institute of Scientific and Technical Information of China (English)

    牛琦; 丁新生

    2012-01-01

    肌萎缩侧素硬化症(ALS)是一种进行性致死性神经变性病,按发病类型分为散发性和遗传性两种.其中,散发性ALS发病率全球相对一致,但在关岛等少数西太平洋地区的人群聚居地发病率有增高现象,且常伴有肌萎缩侧索硬化-帕金森-痴呆叠加症(ALS/PDC).研究发现寄生在苏铁根部的蓝藻菌产生的非蛋白质氨基酸[β-N-甲氨基-L-丙氨酸(BMAA)]与关岛的ALS/PDC发病有关.易感个体长期暴露在富含BMAA的环境中可导致BMAA在神经蛋白中聚集,产生ALS等迟发性进行性神经变性病.本文就蓝藻菌/BMAA作为神经变性病环境致病毒素的假说及其研究进展综述如下.%Amyotrophic lateral sclerosis(ALS) is a progressive fatal neurodegenerative disease. According to heredity, it is divided into sporadic and hereditary subtype. The incidence of sporadic ALS is relatively uniform throughout the world, except for clusters of high incidence among Guam and a few other western Pacific foci. There the disease is often combined with ALS/ Parkinson-dementia complex(PCD). Research on Guam suggested that a non-protein amino acid, P-N-methylamino-L-alanine(BMAA) which produced by cyanobacteria within in specialized roots of the cycads, be relate to the onset of ALS/PDC. Vulnerable individuals can accumulate BMAA in their proteins after long exposure and trigger latent progressive neural degeneration, such as ALS. This review presented the hypothesis of the cyanobacteria/BMAA as environmental toxin and its new insights.

  17. 金原篦羽叶Ctenis kaneharai Yokoyama最完整叶部化石的发现%DISCOVERY OF THE MOST COMPLETE FOSSIL LEAVES OF Ctenis kaneharai Yokoyama

    Institute of Scientific and Technical Information of China (English)

    郑少林; 李海君; 蒋子堃; 张武; 刘忠诚

    2012-01-01

    Some recently discovered fossil leaves of cycad (Ctenis kaneharai Yokoyama) from the Middle Jurassic Haifanggou Formation in Changlongdigou, Beipiao, Western Liaoning Province are summarily reported. This species of fossil plant was firstly described by Japanese researcher Yokoyama from the Middle Jurassic Dabao Formation of Nianzigou, Fengcheng, Eastern Liaoning. Later on, it was also found in Japan and England. However, all the previously reported specimens are some fragments of the fossil plant, so that people could not know the complete picture of the plant. The specimens reported in this paper are not only plenty in number, but also conserved intact. Undoubtedly, these fossil plants are the best conserved so far for this genus in the Middle Jurassic Yanliao Flora. The present discovery of these specimens is significantly important for the paleoecology, paleoclimatology and other researches on the Yanliao Flora in China.%概要报道产于辽西北票市常河营乡长垅地沟村东山中侏罗统海房沟组中一种大型苏铁类叶部化石——金原篦羽叶Ctenis kaneharai Yokoyama.这种化石最早被报道于辽宁东部凤城县赛马集碾子沟中侏罗统大堡组,后来在日本和英国也被发现.但是,以往发表的该种所有材料都是些植物叶部断片标本,对它的全貌并不了解.在本文中报道的该种标本,不仅数量多而且保存得特别完整.可以说,这是迄今在我国辽西中侏罗世燕辽植物群中大型苏铁类保存最完整叶部化石的又一次重要发现.它为正确了解我国燕辽植物群的性质,苏铁类的整体形态特征和古气候状况分析,提供了更为可靠的化石依据.

  18. Leaf Litter Decomposition of Main Subtropical Plants with Different Origin Time in the South Subtropical Asia%不同起源时间的亚热带主要树种凋落物在南亚热带的分解研究

    Institute of Scientific and Technical Information of China (English)

    姜小丽; 窦荣鹏; 江洪; 余树全; 马元丹

    2012-01-01

    [ Objective ] Study the leaf litter decomposition of main plants with different origin time in the south subtropical Chinese. [ Method ] Leaf litter decomposition of 9 species with different origin time was studied in the Dinghushan region, using iitterbag method, the time was 840 days, to study the variation of litter dry weight remaining and carbon dynamics in evolutionary process. [ Result ] The range of the annual litter decomposition coefficient(k) was 0.14 to 0. 71. The 95% decomposition time ranged from 4. 22 to 21.40 a, and the 50% decomposition time ranged from 0. 98 to 4. 95 a. The difference of litter decomposition rate with monocotyledon, gymnosperm, pteridophyte was significant( P C. glauca > S. superba > P. massoniana > C. lanceolata > M, glyptostroboides > C. revoluta > A. spinulosa > D. dichotoma. The mean litter decomposition rate of the 4 taxa was monocotyledon > dicotyledon > gymnosperm > pteridophyte. The carbon loss of the 4 taxa was dicotyledon > monocotyledon > gymnosperm > pteridophyte.%[目的]研究不同起源时间的亚热带主要树种凋落物的分解过程.[方法]选择9种起源时间不同的植物的凋落物,采用分解袋法,在南亚热带的鼎湖山地区进行分解实验,实验时间为840d,研究进化过程中凋落物的干重剩余率和碳素动态变化规律.[结果]凋落物分解系数k值的范围在0.14~0.71间.凋落物分解95%所需时间集中在4.22~21.40 a,50%分解时间集中在0.98 ~4.95a.单子叶植物、裸子植物和蕨类植物两两之间分解速率均具有显著差异(P<0.05),但双子叶植物与单子叶植物和裸子植物分解速率之间显著性差异不明显,仅与蕨类植物的分解速率具有显著差异(P<0.05).凋落物总碳量的总体变化趋势表现为下降,在分解过程中均出现2次不同程度的升高过程,出现时间集中在分解的第240天和660天,此时正值冬季,凋落物分解较慢,碳元素出现积累.双子叶植物、裸子植

  19. Fossil Plants from the Bantou Formation of Yong' an,Fujian Province and Their Paleoclimatic Significance%福建永安坂头组植物及古气候分析

    Institute of Scientific and Technical Information of China (English)

    戴静; 孙柏年; 谈树成; 高博; 赵志芳; 王永栋

    2013-01-01

    分析了福建永安盆地早白垩世坂头植物群的组成特征.共计报道该植物群化石24属52种左右,包括未定种以及存疑种21个.植物群的组成以具鳞片状叶的松柏类化石为主,苏铁类化石次之,并以本内苏铁目占绝对优势,然后是真蕨类化石,以小羽片小而质厚为特征,银杏化石及其少见,未发现被子植物.坂头组植物的组成面貌与欧洲Wealden植物群、日本外带领石植物群,以及我国南方植物区,如浙江、山东等地的早白垩世植物群比较一致,说明坂头组合化石层位年龄为早白垩世早期.坂头组大多数植物主要分布于热带或亚热带地区,具有耐干旱炎热的特点,反映了较干旱而炎热的气候特征.除此之外,还发现少量适宜生活在温凉潮湿气候环境下的植物.根据这些对气候具有指示意义的代表分子在坂头组中的数量以及分布情况,推断永安盆地早白垩世早期气候总体上比较干旱炎热,且伴随有不同程度季节性的潮湿.%The composition of fossil plants from the Bantou Formation of Yong'an, western Fujian Province, is analyzed and summarized. 52 species (including 21 indeterminate and suspicious species) ascribed to 24 genus have been reported from the formation up to now. Among them, the conifers with spiral scales are dominant; cycads are mainly composed of Bennettitales; ferns are characterized by small and thick pinnules; Ginkgoales are very few, and angiosperms are absent. The fossil assemblage of the Bantou Florais comparatively consistent with that of the Wealden Flora in Europe, the ryoseki Flora in outer zone of Japan, as well as the Early Cretaceous floras from the South Floristic Region in China, such as Zhejiang and Shandong provinces. This indicates that the age of fossil beds of the Bantou Formation is early Early Cretaceous. Meanwhile, most of the species from the Bantou Formation are xerophilous and are mainly distributed in tropical and

  20. 《植物分类学报》参考文献引证格式

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    例 1: Abell B C, Tagg R C, Push M, 1954. Enzyme catalyzed cellular transamination. In: Round A F ed. Advances in Enzymology. 3rd ed. New York: Academic Press. 2: 125~147 例 2: Erdtman G, 1952. Pollen Morphology and Plant Taxonomy——Angiosperm. (王伏雄和钱南芬译, 1962. 花粉形态与植物分类.北京: 科学出版社. 50~76) 例 3: Grant V, 1963. Origin of Adaptation. New York: Columbia University Press. 1~5 例 4: Soltis D E, Haufler C H, Darrow D C et al., 1983. Starch gel electrophoresis of ferns: A compilation of grinding buffers, gel and electrode buffer, and staining schedules. Amer Fern J, 73(1): 9~29 例 5: Wu Z -Y(吴征镒), 1979. The regionalization of Chinese Flora. Acta Bot Yunnan (云南植物研究), 1(1): 1~22 例 6: Wang F-X(王发祥), Liang H-B(梁惠波), 1996. Cycads in China. Guangzhou: Guangdong Sci. & Tech. Press. 3~10 说明: 1. 论文末尾的参考文献表: (1) 中文文献如有英文标题应以英文著录, 但作者姓名和刊物名称需有中文对照(例5,6)。如文献本身确无英文标题就用中文,不必译成英文。原则上文中只引所见原文献;如未见原文献,最好采用“转引自……”的方式,文末只引所见文献。 (2) 著者3个以内(含3个)要全列(例1), 3个以上的部分用“等”(et al.)表示(例4)。 (3) 文献的排列以汉、西、俄等文字及作者姓氏的首字母为序。姓列名前, 姓首字母大写, 名缩写, 不加缩写点。中国作者为双名者, 两缩写字母间以对开号(-)相连(例6)。 (4) 图书要写版次(初版不写)(例1), 请注意按格式写清楚“出版社地点:出版社名.卷(册):页”(例1,2)。 (5) 论文题目的第一字母大写,余小写(例1,4);书(包括论文集)名每个实词首字母大写,余小写(例1,6)。其他文种大小写按该文种习惯。 (6) 论文集里的论文引用见例1。其中,中文用“见:”,英文用“In:”; 一个作者用ed(例1), 多作者用eds。 (7