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1.
Species identification of Scenedesmus-like microalgae, comprising Desmodesmus, Tetradesmus, and Scenedesmus, has been challenging due to their high morphological and genetic similarity. After developing a DNA signaturing tool for Desmodesmus identification, we built a DNA signaturing database for Tetradesmus. The DNA signaturing tool contained species-specific nucleotide sequences of Tetradesmus species or strain groups with high similarity in ITS2 sequences. To construct DNA signaturing, we collected data on ITS2 sequences, aligned the sequences, organized the data by ITS2 sequence homology, and determined signature sequences according to hemi-compensatory base changes (hCBC)/CBC data from previous studies. Four Tetradesmus species and 11 strain groups had DNA signatures. The signature sequence of the genus Tetradesmus, TTA GAG GCT TAA GCA AGG ACCC, recognized 86% (157/183) of the collected Tetradesmus strains. Phylogenetic analysis of Scenedesmus-like species revealed that the Tetradesmus species were monophyletic and closely related to each other based on branch lengths. Desmodesmus was suggested to split into two subgenera due to their genetic and morphological distinction. Scenedesmus must be analyzed along with other genera of the Scenedesmaceae family to determine their genetic relationships. Importantly, DNA signaturing was integrated into a database for identifying Scenedesmus-like species through BLAST.  相似文献   

2.
  1. Rabbit antisera to soluble cytochrome c-553 and to ferredoxin were characterized by double immunodiffusion, the antiserum to cytochrome c-553 also by immuno-electrophoresis and by the quantitative precipitation reaction.
  2. Soluble cytochromes c-553 were isolated from 11 strains of Chlorella belonging to 8 species and from one strain of Scenedesmus. Their reactivity with antiserum to soluble cytochrome c-553 from Chlorella fusca var. vacuolata 211-8b was studied.
  3. With the double immunodiffusion method, the soluble cytochromes c-553 from C. fusca var. vacuolata 211-8b, C. fusca var. rubescens 232/1, C. fusca var. fusca 343, and Scenedesmus obliquus 276-3b appear immunologically identical.
  4. The soluble cytochromes c-553 from C. zofingiensis 211-14a, 211-14b, and 211-14c show in the cross reaction a partial immunological relationship with that from C. fusca var. vacuolata 211-8b.
  5. The soluble cytochromes c-553 from C. sorokiniana 211-8k, C. vulgaris 211-11c and 211-19, C. saccharophila 211-1 a, and C. homosphaera 211-8e (Ca.) do not show a cross reaction with that from C. fusca var. vacuolata 211-8b.
  6. These results indicate that not only C. fusca var. fusca, but also C. fusca var. vacuolata, C. fusca var. rubescens, and possibly C. zofingiensis might be more closely related to the genus Scenedesmus than to the Chlorella species of the “C. vulgaris group” (i.e., C. sorokiniana, C. vulgaris, and C. saccharophila).
  7. An application of the double immunodiffusion method with an antiserum to ferredoxin from C. vulgaris 211-8m revealed that the ferredoxins from 20 strains of 9 Chlorella species and from one strain of Scenedesmus do not exhibit any immunological differences as compared to the homologous antigen.
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3.
Phylogenetic relationships within the genusChlorella were studied by means of DNA/DNA hybridization under both optimal and relaxed reassociation conditions as well as by determination of the thermal stability of hybrid DNA duplexes. The results indicate a relationship betweenC. fusca var.fusca, C. fusca var.rubescens, C. fusca var.vacuolata, and the genusScenedesmus. In addition, the strains endosymbiotic withParamecium bursaria seem to be related with theC. vulgaris/sorokiniana group. The relations between most other species, however, could not be sufficiently resolved by the above methods. This implies considerable phylogenetic divergency within the genusChlorella.  相似文献   

4.
The subgenus Selenkothuria comprises 12 species of tropical shallow water sea cucumbers that share morphological features, such as rods in the body wall and tube feet, modified tentacles for suspension feeding, and cryptic colours. The taxonomic status of this taxon has been controversial, but currently it is accepted as a subgenus of the genus Holothuria. Phylogenetic analyses of mitochondrial genes [cytochrome c oxidase subunit 1 (COI), 16S RNA] of ten species of Selenkothuria and related subgenera showed the polyphyly of this subgenus; monophyly was rejected by a likelihood ratio test. A geographical split divides the species of this subgenus into three different groups: one Indo‐West‐Pacific (IWP) group and two American groups. The IWP group is more closely related to Holothuria (Semperothuria) cinerascens and to other subgenera such as Roweothuria, Holothuria, and Vaneyothuria, whereas the two American groups are more closely related to each other and to some species of the subgenus Halodeima. These results suggest multiple parallel originations and diversification of ossicle morphology within the subgenus Selenkothuria. The current scheme of subgenera for the genus Holothuria is not supported, suggesting the need for a new classification. © 2012 The Linnean Society of London, Zoological Journal of the Linnean Society, 2012, 165 , 109–120.  相似文献   

5.
6.
The subgeneric subdivision of the genus Formica is still open. In this article, we make a phylogenetic study on several species of the genus Formica and of its closely related genera, Polyergus and Proformica, using sequences of nuclear satellite DNA (stDNA) and the mitochondrial rrnL as molecular markers. Our goal was to shed light on their phylogenetic relationships and particularly on the systematic position of F. subrufa. This species was first included in the subgenus Serviformica, but afterwards a new subgenus (Iberoformica) was established to include only this species. The results show that a stDNA family previously reported in Formica species, with a repetitive unit 129 bp long, is also found in Polyergus rufescens and P. samurai but not in Proformica longiseta. This is the first case of presence of a stDNA family in two different ant genera. In F. subrufa, this stDNA is very divergent relative to those isolated in the remaining Formica species and in the genus Polyergus. The Bayesian analysis of mitochondrial rrnL sequences shows three highly supported groups: F. subrufa, the remaining Formica species studied, and the genus Polyergus, suggesting that parasites (Polyergus species) and hosts (Formica species) are closely related but not sibling species. The combined analysis of nuclear stDNA sequences and mitochondrial rrnL showed their phylogenetic congruence despite their distinct evolutionary dynamics. This analysis did not discriminate between the remaining Formica species that were not grouped according to the subgeneric classification. According to these results, it can no longer be assumed that F. subrufa belongs to the subgenus Serviformica or of the fusca species group. This differentiation was also supported by previous studies based on the morphological characters, molecular and cytogenetic data. Therefore, taking into consideration these arguments and others explained in detail in this article, we propose that the taxon Iberoformica, formerly synonymized subgenus, be raised to a genus status. This genus would be monotypic and only composed, up to the moment, by Iberoformica subrufa (= F. subrufa Roger, 1859 ).  相似文献   

7.
Fruit flies of the genus Bactrocera (Diptera: Tephritidae) are one of the major economically important insects in Asia and Australia. Little attention has been given to analyses of molecular phylogenetic relationships among Bactrocera subgenera. By using mitochondrial cytochrome oxidase I gene (COI) sequences, the phylogenetic relationships among four subgenera, Asiadacus, Bactrocera, Hemigymnodacus, and Zeugodacus, were investigated. Nucleotide diversity within subgenera ranged from 11.7 to 12.4%, and the net divergence among subgenera ranged from 11.2 to 15.7%. Phylogenetic trees calculated from both maximum parsimony and neighbor-joining phylogenetic analysis methods were highly congruent in terms of tree topologies. Phylogenetic analysis of mitochondrial COI sequences suggests that tephritid fruit fly species, which attack cucurbit plants, that is, Asiadacus, Hemigymnodacus and Zeugodacus, were more closely related to each other than to fruit fly species of the subgenus Bactrocera, which attack plants of numerous families. Our data supports previous classification of Bactrocera based on morphological characters. However, the phylogenetic tree showed the polyphyletic of fruit flies in subgenus Zeugodacus. Possible causes of speciation among fruit flies species in this genus were also discussed.  相似文献   

8.
Secondary structure analysis of 34 internal transcribed spacer 2 (ITS-2) sequences showed that the current model for the green algae Scenedesmus and Desmodesmus is not accurate. In particular, helix I of the currently used model showed considerable deviations from our new model. The newly proposed model is supported by many two-sided compensated base pair changes and fully compensated insertions in all four helices. Phylogenetic analysis by maximum parsimony based on the new alignment confirmed the recent division of the old genus Scenedesmus into the new genera Scenedesmus and Desmodesmus. However, the analysis was not able to show phylogenetic relationships within these two genera. Hence, the ITS-2 region alone is not suitable for clarifying the phylogeny of Scenedesmus and Desmodesmus and new regions have to be found for future sequence analyses.  相似文献   

9.
Sequences from the ribosomal DNA internal transcribed spacer‐2 (ITS‐2) were compared among species of Sargassaceae including the genera Sargassum and Hizikia. Species of different subgenera and sections of Sargassum were used to assess the taxonomic relationships within the genus, especially the subdivisions of the subgenus Bactrophycus. Sequences were aligned in accordance with their common secondary structure. Phylogenetic trees were constructed using neighbor‐joining, maximum likelihood and maximum parsimony methods with three species of Turbinaria as outgroups. The resulting phylogenetic trees showed that the genus Sargassum is divided into three clades corresponding to the subgenera Phyllotrichia, Sargassum and Bactrophycus. This last subgenus is further divided into four distinct groups: a Spongocarpus clade, a Teretia clade, a Hizikia clade, and a Halochloa/ Repentia clade. The position of the section Phyllo‐cystae, excluded from the subgenus Bactrophycus and included within the subgenus Sargassum is once again confirmed by the present study. Current results strongly support the assignation of Hizikia fusiformis to the genus Sargassum. Based on morphological differences and a distinct position in the molecular trees, Hizikia should be recognized as a section in the subgenus Bactrophycus so that Hizikia (Okamura) Yoshida, stat. nov. is proposed. A remarkably low divergence of ITS‐2 sequences was observed for the species in the sections Repentia and Halochloa, suggesting very recent radiation of these species. The subgenus Sargassum is divided into three clades corresponding to the three known sections: Acanthocarpicae, Malacocarpicae and Zygocarpicae, previously recognized by the morphology of receptacles. The position of Sargassum duplicatum, S. carpophyllum, S.yendoi, S. piluliferum and S. patens within the subgenus Sargassum is discussed.  相似文献   

10.
The genus Auletobius in the Russian fauna is revised. Five species (A. egorovi, A. irkutensis, A. puberulus, A. sanguisorbae, and A. submaculatus) belonging to two subgenera are revealed. The distribution of these species in Russia is given. The data on the trophic associations of the species are summarized. Keys to the subtribes of the tribe Auletini, subgenera of the genus Auletobius, and species of the subgenus Auletobius s. str. are given. All the taxa are redescribed.  相似文献   

11.
DNA hybridization techniques showed Chlorella fusca var. vacuolata and C. kessleri to be homogeneous species with DNA homologies of 90–100% C. fusca var. fusca and var. rubescens, however, have only about 15% DNA homology with C. fusca var. vacuolata and should no longer be regarded as varieties. A good correlation was found so far between biochemical and physiological characters used in the taxonomy of Chlorella and DNA relatedness. Mutant strains of Chlorella were tested for DNA homologies to prove the reliability of the taxonomical interpretation.  相似文献   

12.
Many arthropods with restricted diets rely on symbiotic associations for full nutrition and fecundity. Tsetse flies (Diptera: Glossinidae) harbor three symbiotic organisms in addition to the parasitic African trypanosomes they transmit. Two of these microorganisms reside in different gut cells, while the third organism is harbored in reproductive tissues and belongs to the genus Wolbachia. The primary symbiont (genus Wigglesworthia glossinidia) lives in differentiated epithelial cells (bacteriocytes) which form an organ (bacteriome) in the anterior gut, while the secondary (S) symbionts are present in midgut cells. Here we have characterized the phylogeny of Wigglesworthia based on their 16S rDNA sequence analysis from eight species representing the three subgenera of Glossina: Austenina (=fusca group), Nemorhina (=palpalis group), and Glossina (=morsitans group). Independently, the ribosomal DNA internal transcribed spacer-2 (ITS-2) regions from these species were analyzed. The analysis of Wigglesworthia indicated that they form a distinct lineage in the γ subdivision of Proteobacteria and display concordance with their host insect species. The trees generated by parsimony confirmed the monophyletic taxonomic placement of Glossina, where fusca group species formed the deepest branch followed by morsitans and palpalis groups, respectively. The placement of the species Glossina austeni by both the traditional morphological and biochemical criteria has been controversial. Results presented here, based on both the ITS-2 and the symbiont 16S rDNA sequence analysis, suggest that Glossina austeni should be placed into a separate fourth subgenus, Machadomyia, which forms a sister-group relationship with the morsitans group species. Received: 17 March 1998 / Accepted: 1 May 1998  相似文献   

13.
The internal transcribed spacer (ITS1, 5.8S rDNA, and ITS2) region of nuclear ribosomal DNA (nrDNA) was sequenced from 53 species, which represent most of the living species diversity in the genus Phalaenopsis (Orchidaceae). A phylogeny was developed for the genus based on the neighbor-joining and maximum parsimony analyses of molecular data. Results of these analyses provided support for the monophyly of the genus Phalaenopsis and concurred in that the genera Doritis and Kingidium should be treated as being parts of the genus Phalaenopsis as suggested by Christenson (2001). Within the genus Phalaenopsis, neither subgenera Aphyllae nor Parishianae were monophyletic, and they were highly clustered with subgenus Proboscidioides plus sections Esmeralda and Deliciosae of subgenus Phalaenopsis based on ITS data. Those species also have the same characters of morphology of four pollinia and similar biogeographies. Furthermore, neither subgenus Phalaenopsis nor Polychilos was monophyletic. Within the subgenus Phalaenopsis, only section Phalaenopsis was highly supported as being monophyletic. As for the subgenus Polychilos, only section Polychilos was moderately supported as being monophyletic. In conclusion, the present molecular data obtained from the ITS sequence of nrDNA of the genus Phalaenopsis provide valuable information for elucidating the phylogeny of this genus.  相似文献   

14.
Ainscough, B.J., Breinholt, J.W., Robison, H.W. & Crandall, K.A. (2013). Molecular phylogenetics of the burrowing crayfish genus Fallicambarus (Decapoda: Cambaridae). —Zoologica Scripta, 42, 306–316. The crayfish genus Fallicambarus contains 19 species of primary burrowing freshwater crayfish divided into two distinct subgenera. We test current hypotheses of the phylogenetic relationships among species within the genus as well as the monophyly of the genus. Our study samples all 19 species for five gene regions (both nuclear and mitochondrial) to estimate a robust phylogenetic hypothesis for the genus. We show that the genus is not a monophyletic group. The subgenus Creaserinus does fall out as a monophyletic group, but distinct from the subgenus Fallicambarus. The subgenus Fallicambarus appears to be monophyletic with the exception of the species Procambarus (Tenuicambarus) tenuis, which falls in the midst of this subgenus suggesting that it might be better classified as a Fallicambarus species. We also show that the species Fallicambarus fodiens is a species complex with distinct evolutionary lineages that are regionalized to different geographic areas.  相似文献   

15.
Nine isolates of unicellular green algae were obtained from six geographically separate desert microbiotic crust communities in western North America. Microscopically, eight isolates strongly resembled unicellular forms of Scenedesmus obliquus (Turpin) Kützing. They are oval or crescent shaped, often flattened on one side, with knobby cell apices. SEM indicated a lack of wall ornamentation. Fine filaments connecting cells pole to pole were observed in some isolates, as previously documented in Scenedesmus (Dactylococcus) dissociatus and S. obliquus. The ninth isolate was spherical, without knobby apices or connections between cells, and was similar to unicellular forms that were originally classified as species of Chlorella (Scenedesmus vacuolatus and S. rubescens). None of the isolates formed coenobia in liquid culture. Phylogenetic analysis of the 18S rRNA gene placed all desert isolates in the genus Scenedesmus, separating them into two or three weakly resolved groups along with published sequences of other Scenedesmus isolates. Phylogenetic analyses of the internal transcribed spacer region revealed well‐supported lineages of desert algae that were unsupported with 18S data alone. The eight S. obliquus‐like desert strains formed two distinct clades that excluded the S. obliquus strains from geographically widespread nondesert habitats. The ninth strain was outside of the S. obliquus group, associated with S. raciborskii and S. pectinatus. These results demonstrate three lineages of Scenedesmus from desert soils and provide robust support for the presence of cryptic species in S. obliquus, a morphospecies that is said to have a cosmopolitan distribution. Three new species of Scenedesmus are described.  相似文献   

16.
Genus Scytodes includes most species of the spider family Scytodidae. Until now, 187 species of the genus have been described. In spite of this great diversity, only three Scytodes species were karyotyped so far. The present paper provides for the first time karyotype analysis of two synanthropic species, Scytodes fusca and Scytodes itapevi. Furthermore, new data on karyotype of Scytodes globula are also provided using conventional and differential cytogenetical procedures. The diploid number in the genus Scytodes varied considerably, namely from 2n = 13 to 2n = 31. The diploid number found in S. globula (2n♂ = 13) is the lowest in haplogyne spiders with monocentric chromosomes. Except S. globula, this number has been found only in one haplogyne spider with monocentric chromosomes, namely Ochyrocera sp. (Ochyroceratidae). On the contrary, the diploid number of S. fusca (2n♂ = 31) is one of the highest diploid numbers recorded in haplogyne spiders. The degree of intrageneric variation found in the genus Scytodes is the highest recorded in araneomorph spiders with monocentric chromosomes so far. Some karyotype characteristics (diploid number, chromosome morphology, total chromosome length, and distribution of constitutive heterochromatin) allowed us to postulate a close relationship between S. globula and S. itapevi. According to the karyotype data, S. fusca is not closely related to these two species. This conclusion corroborates a recent taxonomic work that grouped S. globula, S. itapevi, and other four Scytodes species in the ‘globula group’.  相似文献   

17.
The myobiid genus Acanthophthirius Perkins, to date comprising four subgenera, is reviewed and divided into just two subgenera, the nominate subgenus and Myotimyobia Fain. The male genital shield and female opisthogastric sclerites, which are here considered to be part of female genitalia, are adopted as the criteria for dividing the subgenera. These structures are essentially the same in form and position in the subgenus Acanthopthirius in its revised sense, while they are both more heterogeneous in species of the redefined subgenus Myotimyobia. The subgenera Acanthophthirius Fain and Chiromyobia Fain are thought to represent species-groups in the nominate subgenus, named respectively the etheldredae and miniopteri groups. The following one new subspecies and 11 new species are described: A. (A.) womersleyi eptesicus, A. (A.) glauconycteris, A. (A.) mauritaniensis, A. (A.) philetoris, A. (A.) otonycteris, A. (A.) steatocaudatus, A. (A.) nyctophilis, A. (M.) vagus, A. (M.) longus A. (M.) baueris, A. (A.) hesperopteris (female only) and A. (M.) pixonixeos (female only). A. (M.) hanensis is synonymised with A. (M.) namurensis, and A. (M.) capacini is emended to A. (M.) capaccinii and relegated to a subspecies of A. (M.) myotis. All the known and new species are assigned to their respective subgenera and shown in a table. Incongruent host-relationships of some of the mites are clarified, although not completely solved, by the introduction of the new classification for the subgenera.  相似文献   

18.
Chloroplast DNA (cpDNA) restriction site variation was examined in 32 species, representing five subgenera, of Bromus (Poaceae). Thirty-seven phylogenetically informative restriction sites were detected. Cladistic analysis of the restriction site data produced a single most-parsimonious tree of 50 steps. The cladogram indicated two major clades within the genus. One clade included B. trinii of subgenus Neobromus and species of subgenus Ceratochloa. The other was composed of subgenera Festucaria, Stenobromus, and Bromus. Within the second clade, species of subgenus Festucaria appeared in three lineages. The second clade also contained an assemblage of species belonging to subgenera Stenobromus and Bromus in a separate lineage. There was very little resolution of relationships in this assemblage since several species appeared individually in separate lineages. The cpDNA phylogenetic hypothesis did not separate species of subgenera Stenobromus and Bromus into well-defined clades as circumscribed by morphology and cytogenetics. The cpDNA tree is in agreement with the phylogenetic scheme based on traditional data in that: 1) subgenera Neobromus and Ceratochloa were the first to diverge, while Bromus and Stenobromus diverged later; 2) within the genus Bromus species with small chromosomes are ancestral; and 3) subgenera Bromus and Stenobromus probably originated from similar ancestors as Festucaria. The tree based on cpDNA data does not support that: 1) subgenera Neobromus and Ceratochloa did not have a common origin; 2) subgenus Festucaria is monophyletic; and 3) subgenera Stenobromus and Bromus are distinct entities. The mean nucleotide sequence divergence values between pairs of subgenera ranged from p = 0.0 to 0.9. These values suggest that cpDNA evolution in Bromus is slow.  相似文献   

19.
Pollen grains from ten species of Gunnera, chosen to represent the six different subgenera in the genus, were examined using light and scanning electron microscopy. The aim of the study was to explore characters that have the potential to define different types of pollen within Gunnera and to study the evolution of these characters in light of the phylogeny of the genus. According to our results, there are three main types of pollen in the examined species of Gunnera. Type 1, unique for the South American species G. herteri (subgenus Ostenigunnera), is characterised by an imperfect reticulum with sinuous undulating-creasted muri. A reticulum with equidimensional polygonal lumina is typical for the plesiomorphic type of pollen (type 2) present in subgenera Gunnera, Misandra and Panke. Lastly, pollen grains of subgenera Pseudogunnera and Milligania are characterised by a reticulum with lumina of variable shape and size (type 3). In G. macrophylla (subgenus Pseudogunnera), the lumina in the apocolpia are of a different shape and size from the lumina in the mesocolpia (type 3a), while in G. dentata, G. monoica and G. cordifolia (subgenus Milligania), the lumina are identical in the apocolpium and the mesocolpium (type 3b).

The identification of pollen types will possibly allow the interpretation of the different specimens of Tricolpites reticulatus, the fossil species believed to be allied to the extant Gunnera.

In addition to the revision on the pollen of Gunnera, a brief comparison between the pollen of this genus and its sister group Myrothamnus is reported.  相似文献   

20.
Abstact  Genetic diversity in the four east Palearctic ground squirrel species of the genus Spermophilus—S. undulatus, S. parryi (subgenus Urocitellus), S. dauricus, and S. relictus (subgenus Citellus)—was investigated using RAPD PCR with ten random primers. Siberian chipmunk, Tamias sibiricus, was used as an out-group. Molecular markers for different taxonomic ranks were identified, including those for the genera Spermophilus and Tamias, subgenera Urocitellus and Citellus, as well as for each of the four species, S.undulatus, S. parryi, S. dauricus, and S. relictus. For the ground squirrel species and subgenera, genetic differentiation indices (H t, H s, D st, G st,Nm, and D) were calculated. In addition, for these groups the NJ phylogenetic reconstructions and UPGMA dendrograms of genetic similarity of the individuals and combined populations were constructed. Comparative molecular genetic analysis revealed a high genetic differentiation between S. undulatus, S. dauricus, S. relictus, and S. parryi (G st= 0.58 to 0.82; D= 0.53 to 1.06), along with a low level of genetic differentiation of the subgenera Citellus and Urocitellus (G st = 0.33; D= 0.27), distinguished in accordance with the existing taxonomic systems of the genus Spermophilus Original Russian Text ? M.V. Tsvirka, L.N. Spiridonova, V.P. Korablev, 2008, published in Genetika, 2008, Vol. 44, No. 8, pp. 1108–1116.  相似文献   

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