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1.
TnphoA mutagenesis identified an open reading frame,roa307, immediately upstream of the partition locusqsopAB on theCoxiella burnetii plasmid QpH1. The protein sequence deduced fromroa307 displayed homology to Orf290 ofPseudomonas putida, Orf283 and Orf282 (SpoOJ) ofBacillus subtilis —hypothetical products of genes in the chromosomal replication origin region. Expression ofroa307 was demonstrated by PhoA activity of an Roa307-PhoA fusion. 相似文献
2.
Two lignicolous species ofMycena (Agaricales, Basidiomycetes) are described and illustrated from eastern, Japan:Mycena auricoma sp. nov., forming ephemeral coprinoid basidiomata and belonging to sectionRadiatae, was found on a dead fallen twig ofQuercus serrata. It appears to close to a Malaysian species,“Trogia” crinipelliformis. Mycena spinosissima in sectionSacchariferae, new to Japan, was collected from dead bark ofAphananthe aspera, a dead fallen inflorescence ofCryptomeria japonica, and a dead fallen twig ofQuercus serrata. 相似文献
3.
Intergeneric crosses were made between representatives of the genomically-defined generaElymus, Agropyron, Elytrigia, Pseudoroegneria, andThinopyrum. The genomic constitution ofElytrigia repens, the type species ofElytrigia, is shown to be SSH, a genomic combination otherwise found only inElymus. The S genome ofPseudoroegneria has almost always a dominant influence on the morphology of the taxa of which it is a component.Wang (1989) showed that the J genome inThinopyrum and the S genome have considerable homoeology, with a mean c-value of 0.35 in diploid SJ hybrids. A genetic coherence from S to SJe, Je, JeJb, and Jb can be expected, agreeing with the continuous morphologic variation pattern observed. Because of the absence of morphological discontinuities between the taxa,Pseudoroegneria (S),Elymus (SH, SY, sometimes with additional genomes),Elytrigia (SSH, SSHX), andThinopyrum (SJ, SJJ, J) are best treated as a single genus,Elymus, following the generic concept ofMelderis in Flora Europaea and Flora of Turkey. The basic genomic constituents ofElymus will then be the S and/or J genomes.Agropyron, with diploids, tetraploids, and hexaploids based on the P genome is morphologically distinct from other genera inTriticeae. In a few species ofElymus andPseudoroegneria, a P genome is an additional constituent. In these cases the P genome has a negligible morphological influence. Therefore, it seems reasonable to maintainAgropyron as a separate genus. 相似文献
4.
We have used total genomic DNA as a probe to size-fractionated restriction enzyme digests of genomic DNA from a range ofTriticeae species from the generaLeymus
Hochst.,Psathyrostachys
Nevski, andHordeum L., and hybrids betweenHordeum andLeymus to investigate their taxonomic relationships. Genomic Southern hybridization was found to be an effective and simple way to assess the distribution and diversity of essentially species-specific and common, repetitive DNA sequences, and is hence especially useful in evolutionary studies. The DNA sequences ofH. vulgare seem to diverge substantially from those ofH. brachyantherum, H. lechleri, H. procerum, andH. depressum. The genome ofThinopyron bessarabicum shows little homology to those of theLeymus species investigated, confirming thatT. bessarabicum is not an ancestral genome inLeymus. Although the genomes ofLeymus andPsathyrostachys share substantial proportions of DNA sequences, they include divergent repeated sequences as well. Hybridization with a ribosomal DNA probe (pTa 71) showed that the coding regions containing structural genes encoding the 18 S, 5.8 S, and 26 S ribosomal RNA were conserved among the species investigated, whereas the intergenic spacer region was more variable, presenting different sizes of restriction fragments and enabling a classification of the species. The rye heterochromatin probe pSc 119.2 hybridized to DNA fromH. lechleri andT. bessarabicum, but not to DNA from the other species investigated. 相似文献
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6.
Birgitta Bremer Richard G. Olmstead Lena Struwe Jennifer A. Sweere 《Plant Systematics and Evolution》1994,190(3-4):213-230
The taxonomic positions ofRetzia, Desfontainia, andNicodemia have been much discussed, and all three genera have been included inLoganiaceae (Gentianales). We have made a cladistic analysis ofrbcL gene sequences to determine the relationships of these taxa toGentianales. Four newrbcL sequences are presented; i.e., ofRetzia, Desfontainia, Diervilla (Caprifoliaceae), andEuthystachys (Stilbaceae). Our results show thatRetzia, Desfontainia, andNicodemia are not closely related toLoganiaceae or theGentianales. Retzia is most closely related toEuthystachys and is better included inStilbaceae. The positions ofDesfontainia andNicodemia are not settled, butDesfontainia shows affinity for theDipsacales s.l. andNicodemia for theLamiales s.l. 相似文献
7.
8.
Craig J. Coates Karyn N. Johnson Harvey D. Perkins Antony J. Howells David A. O'Brochta Peter W. Atkinson 《Genetica》1996,97(1):23-31
We report the cloning ofhermit, a member of thehAT family of transposable elements from the genome of the Australian sheep blowfly,Lucilia cuprina. Hermit is 2716 bp long and is 49% homologous to the autonomoushobo element,HFL1, at the nucleic acid level.Hermit has 15 bp terminal inverted repeats that share 10 bp with the terminal inverted repeats ofHFL1. Conceptual translation reveals a 583 residue open reading frame (ORF) that is 64% similar and 42% identical to theHFL1 ORF. However, the sequence of thehermit element contains two frameshifts within the putative ORF, indication thathermit is an inactive element. Analysis ofL. cuprina strains from within and outside Australia suggested thathermit is present as a single copy in all the genomes analysed. 相似文献
9.
H. -Dietmar Behnke 《Plant Systematics and Evolution》1977,128(3-4):227-235
The exine-sculpturing of pollen fromGisekia africana (Gisekiaceae),Limeum argute-carinatum (Molluginaceae) andHectorella caespitosa (Hectorellaceae) with supratectate spinulae and an anulopunctate tectum is in accordance with the manyCentrospermae investigated so far with the SEM. Pollen ofRhabdodendron macrophyllum and three species fromGyrostemonaceae do not exhibit these surface details. WhileRhabdodendron with a finely reticulate exine probably fits intoRutaceae, the unique columellaless exine ofGyrostemonaceae has no direct counterpart, neither inCentrospermae nor inCapparales, the two orders to which this family was allied. The genera ofGyrostemonaceae can be distinguished by different arrangements of minute pollen surface details.
Zur Skulptur der Pollen-Exine bei drei Centrospermen (Gisekia, Limeum, Hectorella), bei Gyrostemonaceen und Rhabdodendraceen相似文献
10.
RFLPs of cpDNA were examined for 18 species ofAster, six species ofKalimeris, two species ofMiyamayomena and one species and one variety ofHeteropappus from Japan, using 16 restriction endonucleases. Approximately 275 restriction sites were surveyed, and a total of 74 restriction
site mutations was detected, and 31 of these were phylogenetically informative. Sixteen most parsimonious trees constructed
from Wagner parsimony analysis indicated the polyphyly ofKalimeris andMiyamayomena sensu Kitamura;K. miqueliana belongs to a different clade from the remaining species ofKalimeris, and two species ofMiyamayomena did not make a single clade. This result suggests that the shortening or loss of pappus have happened parallelly in different
evolutionary lineages. We must be careful to assess the pappus character in taxonomy and phylogeny, and it is desirable to
examine their phylogenetic relationships using a molecular data. 相似文献
11.
Paraveinal mesophyll (PVM) is a distinctive anatomical feature of the leaf mesophyll of some plant taxa that may represent a specialized physiological compartment. A comprehensive review of the 42 published references that mention PVM or similar cell layers and a survey of 121 of the 272 species of all nine genera of thePhaseoleae subtribeErythrininae demonstrate that PVM is nearly exclusively found inLeguminosae. InLeguminosae, PVM is either rare or absent in subfamilyCaesalpinioideae, uncommon inMimosoideae, and extensively distributed amongPapilionoideae. In subtribeErythrininae, PVM is ubiquitous inErythrina, and occurs in four other genera. ThreeErythrininae genera (Apios, Mucuna, andCochlianthus) lack PVM. Unique chloroplast-poor, enlarged conical cells (pellucid palisade idioblasts) occur in 80 species ofErythrina but not in any other genus ofErythrininae. 相似文献
12.
Puccinia kraussiana, a rust fungus of Africa, was found in Taiwan for the first time in eastern Asia. It was parasiting on leaves ofHeterosmilax gaudichaudiana, on which all four stages were characteristically found. The host species,H. gaudichaudiana, newly added to the host range ofP. kraussiana, constitutes also a new entry to the phanerogamic flora of Taiwan. 相似文献
13.
The solitary endoparasite,Cotesia rubecula, was superior to the gregarious endoparasite,Cotesia glomeratus, in tests of intrinsic competition for their hostArtogeia rapae. When an egg ofC. rubecula was oviposited in the host prior to those ofC. glomeratus, C. rubecula always won the ensuing competition. When an egg ofC. rubecula was laid in the same host within 48 h after oviposition byC. glomeratus, C. rubecula was successful in more than 90% of the interactions. Even when the egg ofC. rubecula was oviposited in the same host 72 to 96 h after oviposition byC. glomeratus, C. rubecula won the competition approximately 33% of the time. The implications of intrinsic competition are discussed in relation to
the establishment ofC. rubecula in an ecosystem containingA. rapae andC. glomeratus.
相似文献
14.
Charles J. O'Kelly Gary L. Floyd Maurice A. Dube 《Plant Systematics and Evolution》1984,144(3-4):179-199
The zoospores and isogametes ofUlvaria obscura var.blyttii, the isogametes ofMonostroma bullosum, and the anisogametes ofM. grevillei have a flagellar apparatus with counterclockwise absolute orientation and terminal caps, and therefore belong to theUlvophyceae. On the basis of the absence or presence of body scales and the morphologies of certain flagellar apparatus components,Ulvaria obscura var.blyttii is retained in theUlvales, whileM. bullosum, M. grevillei andM. oxyspermum are referred to theUlotrichales. Differences in scale morphology, certain flagellar apparatus components, and early thallus ontogeny support the transfer ofM. oxyspermum to the genusGayralia. Mating structures and their positional relationships within the cell are described from the gametes examined. A plasmalemma-associated plaque that may be a degenerate mating structure occurs in someG. oxysperma motile cells. 相似文献
15.
Cástor Menéndez Gabor Igloi Hanspeter Henninger Roderich Brandsch 《Archives of microbiology》1995,164(2):142-151
A gene homologous tomoaA, the gene responsible for the expression of a protein involved in an early step in the synthesis of the molybdopterin cofactor
ofEscherichia coli, was found to be located 2.7-kb upstream of the nicotine dehydrogenase (ndh) operon on the catabolic plasmid pAO1 ofArthrobacter nicotinovorans. The MoaA protein, containing 354 amino acids, migrated on an SDS-polyacrylamide gel with an apparent molecular weight of
40,000, in good agreement with the predicted molecular weight of 38,880. The pAO1-encodedmoaA gene fromA. nicotinovorans was expressed inE. coli as an active protein that functionally complementedmoaA mutants. Its reduced amino acid sequence shows 43% identity to theE. coli MoaA, 44% to the NarAB gene product fromBacillus subtilis, and 42% to the gene product of two contiguous ORFs fromMethanobacterium formicicum. N-terminal sequences, including the motif CxxxCxYC, are conserved among the MoaA and NarAB proteins. This motif is also
present in proteins involved in PQQ cofactor synthesis in almost all the NifB proteins reported so far and in thefixZ gene product fromRhizobium leguminosarum. Mutagenesis of any of these three conserved cysteine residues to serine abolished the biological activity of MoaA, while
substitution of the tyrosine by either serine, phenylalanine, or alanine did not alter the capacity of the protein to complement
themoaA mutation inE. coli. A second Cys-rich domain with the motif FCxxC(13x)C is found close to the C-terminus of MoaA and NarAB proteins. These two
Cys-rich sequences may be involved in the coordination of a metal ions. The pAO1 copy ofmoaA may not be unique in theA. nicotinovorans genome since the molybdopterin cofactor oxidation products were detected in cell extracts from a plasmidless strain. 相似文献
16.
Recent systematic studies ofBartsia andOdontites showed the necessity to exclude the closely related perennial speciesBartsia aspera (Portugal and northern Morocco) andBartsia spicata (Central Pyrenees) from the genusBartsia as a segregate genus namedNothobartsia. Morphologically this new genus combines characteristic features ofBartsia and ofOdontites. Its autonomous systematic position is supported by the cladistic analysis, showing thatNothobartsia represents a relatively primitive genus standing close to the common ancestral root ofBartsia, Euphrasia, andOdontites. 相似文献
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18.
To understand the roles of two well known tumour suppressor genes.l(2)gl andl(2)gd in normal imaginal disc development inDrosophila, we have initiated a study to examine effect of mulations of these genes on the expression of genes involved in the patterning
of the imaginal discs. In this study we show that the expression ofwingless, theDrosophila orthologue of the mammalian oncogeneWnt, is affected in the imaginal discs ofl(2)gl
4
andl(2)gd
1
mutant individuals. In the tumourous wing imaginal discs froml(2)gl mutant larvae, the pattern ofwingless expression was progressively disrupted with an increase in the area of expression, Tumourous wing imaginal discs froml(2)gd homozygous individuals exhibited progressive broadening and extension of the wingless expressing domains. We suggest thatl(2)gl andl(2)gd might be involved in regulating post embryonic expression ofWingless. 相似文献
19.
An investigation of pseudocopulation behaviour in species ofOphrys from southern Spain confirms the close relationship betweenCampsoscolia ciliata (Scoliidae) andOphrys speculum, and betweenEucera nigrilabris (Apoidea) andOphrys tenthredinifera. It could be demonstrated thatEucera barbiventris is the pollinator ofOphrys scolopax subsp.scolopax, whereas other species ofEucera andTetralonia which are active at the same time show no interest at all for the flowers of this species. Special attention was paid to the forms of the taxonomically confusedOphrys fusca group:O. fusca s. str.,O. iricolor, O. omegaifera andO. atlantica. WhileO. fusca s. str. is widespread, small-flowered and has late anthesis,O. iricolor has very large flowers and early anthesis. Each of the four members ofO. fusca agg. in S. Spain is pollinated by a different bee, and selective experiments show that each of these four species of bees is specifically attracted only to one of theOphrys species:Andrena flavipes is the pollinator ofO. fusca s. str.,Colletes cunicularius infuscatus ofO. iricolor, Anthophora atroalba ofO. omegaifera, andChalicodoma parietina ofO. atlantica. These four pollinators belong to 4 different bee families (Andrenidae, Colletidae, Anthophoridae, Megachilidae). As this type of pollination represents a very effective pregamic isolation mechanism, these four taxa ofOphrys fusca agg., at least in southern Spain, behave and should be regarded as genuine species. 相似文献
20.
Anew osteostracan genus and species,Victoraspis longicornualis n. gen., n. sp., is described based on material from Rakovets’, present day Ukraine. This new taxon shares characters with
the two generaStensiopelta
Denison, 1951 andZychaspis
Janvier, 1985. A phylogenetic analysis supports the position ofVictoraspis as the sister group to a monophyleticStensiopelta, while the interrelationships of the various species ofZychaspis are poorly resolved. A morphometric analysis is carried out in an attempt to further resolve the taxonomic affinity. This
analysis groups all examinedZychaspis species closely together, and further supports the establishment ofVictoraspis as separate genus.
相似文献