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1.
Muravenko OV Yurkevich OY Bolsheva NL Samatadze TE Nosova IV Zelenina DA Volkov AA Popov KV Zelenin AV 《Genetica》2009,135(2):245-255
Karyotypes of species sects. Linum and Adenolinum have been studied using C/DAPI-banding, Ag-NOR staining, FISH with 5S and
26S rDNA and RAPD analysis. C/DAPI-banding patterns enabled identification of all homologous chromosome pairs in the studied
karyotypes. The revealed high similarity between species L. grandiflorum (2n = 16) and L. decumbens by chromosome and molecular markers proved their close genome relationship and identified the chromosome number in L. decumbens as 2n = 16. The similarity found for C/DAPI-banding patterns between species with the same chromosome numbers corresponds with
the results obtained by RAPD-analysis, showing clusterization of 16-, 18- and 30-chromosome species into three separate groups.
5S rDNA and 26S rDNA were co-localized in NOR-chromosome 1 in the genomes of all species investigated. In 30-chromosome species,
there were three separate 5S rDNA sites in chromosomes 3, 8 and 13. In 16-chromosome species, a separate 5S rDNA site was
also located in chromosome 3, whereas in 18-chromosome species it was found in the long arm of NOR-chromosome 1. Thus, the
difference in localization of rDNA sites in species with 2n = 16, 2n = 30 and 2n = 18 confirms taxonomists opinion, who attributed these species to different sects. Linum and Adenolinum, respectively. The
obtained results suggest that species with 2n = 16, 2n = 18 and 2n = 30 originated from a 16-chromosome ancestor. 相似文献
2.
An alga known as “Nannochloropsis”, isolated from a prawn farm in Hainan, China, has been critically investigated and identified as Chlorella, a member of the Chlorophyceae based on fatty acid composition, ultrastructure, and 18S rDNA. Cells of this alga were spherical,
measured by 1–6 μm in diameter and were enclosed in thin walls of approximately 0.04 μm thickness. They contained several
small mitochondria, two to three thylakoids and had no vacuoles. There were many pyrenoids in the algal cells and their thylakoid
lamellae were sparse and not translucent. Many lipid droplets were present in the cytoplasm. The total lipid content of this
alga was 3% per gram dry weight and its major fatty acids were C16:0, C18:0, C18:1, C18:2, C18:3 and C20:0. Eicosapentaenoic acid (C20:5, EPA) was not detected. The length of its 18S rDNA sequence was 1,712 bp. 18S rDNA sequence analyses indicated that this
alga was a species of Chlorella. 相似文献
3.
Fujiwara S Yasui K Watanabe K Wakabayashi T Tsuzuki M Iguchi K 《Marine biotechnology (New York, N.Y.)》2003,5(4):401-407
To study phylogenetic relationships among Okinawan soft corals of the genus Clavularia, the ribosomal internal transcribed spacer sequences of host corals and the 18S rDNA sequences of symbiotic algae were analyzed. The molecular phylogenetic trees of hosts showed that a prostanoid-containing species, Clavularia
viridis, is deeply diverged from other species of Clavularia which do not biosynthesize the prostanoids as the main secondary metabolites. Comparison of their trees suggested poor phylogenetic concordance between hosts and symbionts. 相似文献
4.
We investigated a previously unidentified subaerial corticolous strain of the genus Elliptochloris Tschermak-Woess. The alga shares the generic morphological characters with Elliptochloris bilobata, the type species of the genus, but it has a thicker cell wall of adult globular cells, different chloroplast structure and
it also differs in shape of elliptical autospores. The differences of the autospore shape between both species were evaluated
using landmark-based geometric morphometrics. The 18S rDNA gene sequence of the new alga forms a monophyletic clade with the
authentic strain of E. bilobata within the green algal class Trebouxiophyceae close to representatives of the genus Coccomyxa. We describe the new alga as Elliptochloris bilobata var. corticola var. nov.
Presented at the International Symposium Biology and Taxonomy of Green Algae V, Smolenice, June 26–29, 2007, Slovakia. 相似文献
5.
Arabidopsis ACT2 represents an ancient class of vegetative plant actins and is strongly and constitutively expressed in almost all Arabidopsis sporophyte vegetative tissues. Using the beta glucuronidase report system, the studies showed that ACT2 5′ regulatory region was significantly more active than CaMV 35S promoter in Arabidopsis seedlings and gametophyte vegetative tissues of Physcomitrella patens. Its activity was also observed in rice and maize seedlings. Thus, the ACT2 5′ regulatory region could potentially serve as a strong regulator to express a transgene in divergent plant species. ACT2 5′ regulatory region contained 15 conserved sequence elements, an ancient intron in its 5′ un-translated region (5′ UTR),
and a purine-rich stretch followed by a pyrimidine-rich stretch (PuPy). Mutagenesis and deletion analysis illustrated that
some of the conserved sequence elements and the region containing PuPy sequences played regulatory roles in Arabidopsis. Interestingly, mutation of the conserved elements did not lead a dramatic change in the activity of ACT2 5′ regulatory region. The ancient intron in ACT2 5′ UTR was required for its strong expression in both Arabidopsis and P. patens, but did not fully function as a canonical intron. Thus, it was likely that some of the conserved sequence elements and gene
structures had been preserved in ACT2 5′ regulatory region over the course of land plant evolution partly due to their functional importance. The studies provided
additional evidences that identification of evolutionarily conserved features in non-coding region might be used as an efficient
strategy to predict gene regulatory elements. 相似文献
6.
Robinia pseudoacacia microsymbionts from plants growing in Poland and Japan were evaluated for phylogeny and taxonomic position by genomic approach.
Based on the comparative analyses of atpD (368 bp) and dnaK (573 bp) gene sequences as well as 16S rDNA restriction analysis (RFLP-16S rDNA),
R. pseudoacacia microsymbionts were identified as Mesorhizobium strains. In dnaK and atpD gene phylograms R. pseudoacacia nodulators formed robust, monophyletic clusters with Mesorhizobium species with the nucleotide sequence similarity of 91–98% and 90–98%, respectively. The classification of R. pseudoacacia rhizobia to the genus Mesorhizobium was also supported by amplified 16S rDNA restriction analysis. The studied bacteria formed common clusters with Mesorhizobium species, and their DNA patterns were identical or nearly identical to Mesorhizobium genus strains. When DNA-DNA hybridization was performed, the total DNA of the representative R. pseudoacacia rhizobia exhibited 51–75% relatedness to DNA of Mesorhizobium amorphae ICMP15022 strain and below 41% to DNA of other Mesorhizobium species. These results showed that R. pseudoacacia and M. amorphae belong to the same genomospecies. The G+C content of DNA of R. pseudoacacia two microsymbionts was 59.7 and 60.6 mol% compared to 61–64 mol% across M. amorphae strains. 相似文献
7.
Ottem KF Nylund A Karlsbakk E Friis-Møller A Krossøy B Knappskog D 《Archives of microbiology》2007,188(5):547-550
A Francisella strain, GM2212, previously isolated from moribund farmed Atlantic cod (Gadus morhua) in Norway, is closely related to Francisella philomiragia among Francisella spp. according to its complete 16S rDNA, 16S-23S intergenic spacer, 23S rDNA, 23S–5S intergenic spacer, 5S rDNA, FopA, lipoprotein
TUL4 (LpnA), malate dehydrogenase and hypothetical lipoprotein (LpnB) sequences. A comparison between GM2212 and the type
strain of Francisella philomiragia were performed by DNA–DNA hybridization and fatty acid analysis. The DNA–DNA hybridization showed a 70% similarity. The fatty
acid analysis showed only minor differences between the Francisella isolates. Due to the inconclusive result from the DNA–DNA hybridisation, major emphasis concerning the status of this isolate
is made on previously published molecular, phenotypic and biochemical characters. All characteristics taken together support
the establishment of GM2212 as a novel species, for which the name Francisella piscicida sp. nov. is proposed (=CNCM I-3511T = DSM 18777T = LMG registration number not yet
available). 相似文献
8.
Eric Mortreau Sonia Siljak-Yakovlev Malika Cerbah Spencer C. Brown Hélène Bertrand Claudie Lambert 《Tree Genetics & Genomes》2010,6(1):137-148
The subsection Asperae of genus Hydrangea L. (Hydrangeaceae) has been investigated for three reasons: several ambiguous classifications concerning Hydrangea aspera have been published, unexpected differences in genome size among seven accessions have been reported Cerbah et al. (Theor
Appl Genet 103:45–51, 2001), and two atypical chromosome numbers (2n = 30 for Hydrangea involucrata and 2n = 34 for H. aspera) have been found when all other species of the genus present 2n = 36. Therefore, these two species and four subspecies of Hydrangea in all 29 accessions were analyzed for their genome size, chromosome number, and karyotype features. This investigation includes
flow cytometric measurements of nuclear DNA content and bases composition (GC%), fluorochrome banding for detection of GC-
and AT-rich DNA regions, and fluorescent in situ hybridisation (FISH) for chromosome mapping of 5 S and 18 S-5.8 S-26 S rDNA
genes. In the H. aspera complex, the genome size ranged from 2.98 (subsp. sargentiana) to 4.67 pg/2C (subsp. aspera), an exceptional intraspecific variation of 1.57-fold. The mean base composition was 40.5% GC. Our report establishes the
first karyotype for the species H. involucrata, and for the subspecies of H. aspera which indeed present different formulae, offering an element of discrimination. FISH and fluorochrome banding revealed the
important differentiation between these two species (H. involucrata and H. aspera) and among four subspecies of the H. aspera complex. Our results are in agreement with the Chinese classification that places the groups Kawakami and Villosa as two
different species: Hydrangea villosa Rehder and Hydrangea kawakami Hayata. This knowledge can contribute to effective germplasm management and horticultural use. 相似文献
9.
Several chromosome types have been recognized in Citrus and related genera by chromomycin A3 (CMA) banding patterns and fluorescent in situ hybridization (FISH). They can be used to characterize cultivars and species
or as markers in hybridization and backcrossing experiments. In the present work, characterization of six cultivars of P. trifoliata (“Barnes”, “Fawcett”, “Flying Dragon”, “Pomeroy”, “Rubidoux”, “USDA”) and one P. trifoliata × C. limonia hybrid was performed by sequential analyses of CMA banding and FISH using 5S and 45S rDNA as probes. All six cultivars showed
a similar CMA+ banding pattern with the karyotype formula 4B + 8D + 6F. The capital letters indicate chromosomal types: B, a chromosome
with one telomeric and one proximal band; D, with only one telomeric band; F, without bands. In situ hybridization labeling
was also similar among cultivars. Three chromosome pairs displayed a closely linked set of 5S and 45S rDNA sites, two of them
co-located with the proximal band of the B type chromosomes (B/5S-45S) and the third one co-located with the terminal band
of a D pair (D/5S-45S). The B/5S-45S chromosome has never been found in any citrus accessions investigated so far. Therefore,
this B chromosome can be used as a marker to recognize the intergeneric Poncirus × Citrus hybrids. The intergeneric hybrid analyzed here displayed the karyotype formula 4B + 8D + 6F, with two chromosome types B/5S-45S
and two D/5S-45S. The karyotype formula and the presence of two B/5S-45S chromosomes clearly indicate that the plant investigated
is a symmetric hybrid. It also demonstrates the suitability of karyotype analyses to differentiate zygotic embryos or somatic
cell fusions involving trifoliate orange germplasm.
During the submission of this paper, we analyzed 25 other citrus cultivars with the same methodology and we found that the
chromosome marker reported here can indeed distinguish Poncirus trifoliata from grapefruits, pummelos, and one variegated access of Citrus, besides the previously reported access of limes, limons, citrons, and sweet-oranges. However, among 14 mandarin cultivars,
two of them displayed a single B/5S-45S chromosome, whereas in Citrus hystrix D.C., a far related species belonging to the Papeda subgenus, this chromosome type was found in homozygosis. Since these two mandarin cultivars are probably of hybrid origin,
we assume that for almost all commercial cultivars and species of the subgenus Citrus this B type chromosome is a useful genetic marker. 相似文献
10.
To determine the species of the yeast-like symbionts (YLS) in the brown planthoppers (BPH), Nilaparvata lugens, YLS were first isolated and purified by ultracentrifugation from the fat bodies of BPH, and then 18S rDNA and internal transcribed
spacer (ITS)–5.8S rDNA sequences of YLS were amplified with the different general primers for fungi. The results showed that
the two different 18S and ITS–5.8S rDNA sequences of YLS were obtained. One 2291-bp DNA sequence, which contained 18S and
ITS–5.8S rDNA, showed the high similarity to Cryptococcus and was named Cryp-Like symbiotes. Another 1248-bp DNA sequence, which contained a part of 18S and ITS–5.8S rDNA, showed the high similarity
to Pichia guilliermondii and was named Pichia-Like symbiotes. It was further proved that Cryp- and Pichia-Like symbiotes existed in BPH through nested PCR with specific primers for two symbiotes and in situ hybridization analysis
using digoxigenin-labeled probes. Our results showed that BPH harbored more than one species of eukaryotic YLS, which suggested
that diversity of fungal endosymbiotes may be occurred in planthoppers, just like bacterial endosymbiotes. 相似文献
11.
Imed Sbissi Mohamed Neffati Abdellatif Boudabous Claude Murat Maher Gtari 《Antonie van Leeuwenhoek》2010,98(4):429-436
The molecular phylogeny and comparative morphological studies reported here provide evidence for the recognition of the genus
Picoa, an hypogeous desert truffle, in the family Pyronemataceae (Ascomycota, Pezizales). Picoa juniperi and Picoa lefebvrei were reassigned to the genus Picoa based on large subunit (LSU) sequence (28S) rDNA and internal transcribed spacer (ITS) rDNA (including the partial 18S, ITS1,
ITS2, 5.8S gene, and partial 28S of the nuclear rDNA) data. Morphological studies of spores, asci, perida, and gleba revealed
high similarities between P. lefebvrei and P. juniperi, thereby confirming the membership of both species in the genus Picoa. These two species were primarily distinguishable based on ascospore ornamentation. 相似文献
12.
A new species from the Bolivian highlands is described as Elaphoglossum cristatum. It is very similar to E. engelii but is characterized by a (for subsect. Muscosa unique) cristate perispore structure with irregular deposits (versus papillate spores), more densely ciliate petiole scales
(50–80 versus 10–30 cilia per scale), somewhat thicker blade texture, denser scale cover, and paler, more reddish rhizome
scales. 相似文献
13.
Yanhong Yang Shaoxi Cai Yimin Zheng Xiumin Lu Xiuying Xu Yumei Han 《Current microbiology》2009,58(6):635-641
Previously, a new Cordyceps species was isolated from a low altitude area in Chongqing, China, and named Cordyceps chongqingensis sp. nov. In this study, its anamorph was isolated and designated CQM1T. It grew optimally on Czapek medium supplied with 0.5% silkworm flour and 0.5% soybean oil meal at 25°C, pH 5.0–5.5. The
phenotypic and molecular characteristics were investigated for its identification and typing. Morphological observations under
a microscope revealed that this anamorph of Cordyceps chongqingensis sp. nov. was a new species of Metarhizium. Moreover, it was identified as one of the variants of Metarhizium taii based on sequences of 26S rDNA D1/D2 and ITS regions, and thus named Metarhizium taii var. chongqingensis nov. 相似文献
14.
Brandão AD Viccini LF Salimena FR Vanzela AL Recco-Pimentel SM 《Journal of plant research》2007,120(2):317-321
The aim of this work was to determine the cytogenetic characteristics of Brazilian Lippia alba (Mill) N. E. Brown and Lantana camara Plum. that could be useful for future characterization of these genera. Our analyses revealed that Li. alba has 2n=30 chromosomes consisting of ten metacentric and five submetacentric pairs, while La. camara has 44 metacentric chromosomes. The large blocks of heterochromatin seen in both species suggest an apomorphic condition.
Six 45S rDNA sites were detected in both species by fluorescence in situ hybridization (FISH). Two and four 5S rDNA sites
were observed in Li. alba and La. camara, respectively. Meiotic analysis revealed a normal chromosomal behaviour. The number of chromosomes and the presence of 45S
rDNA and 5S rDNA sites do not exclude a possible polyploid origin. The cytogenetic differences between La. camara and Li. alba may be useful markers for differentiating these species. 相似文献
15.
Johnius (Johnius) majan sp. nov. is described on the basis of 8 specimens (117–158 mm in standard length) from Oman, Indian Ocean. The new species
is distinguished from its congeners by the following combination of characters: black axillary spot on upper pectoral fin
base; dorsal soft rays 29–32; anal soft rays 8; scales above lateral line 6, below 11; eye diameter 22.9–28.9% HL; interorbital
width 32.0–38.0% HL; gill rakers 5–6 + 15–18 = 21–24; no mental barbel; last well developed pleural rib on 7th vertebra; swim
bladder appendages 11; vertebrae 10 + 14 = 24. 相似文献
16.
On the family Brassicaceae, the causal agent responsible for downy mildew disease was originally regarded as a single species,
Peronospora parasitica (now under Hyaloperonospora), but it was recently reconsidered to consist of many distinct species. In this study, 11 specimens of Peronospora
drabae and P. norvegica parasitic on the genus Draba were investigated morphologically and molecularly. Pronounced differences in conidial sizes (P. drabae: 14–20 × 12.5–15.5 μm; P. norvegica: 20–29 × 15.5–22 μm) and 7.8% sequence distance between their ITS1-5.8S-ITS2 rDNA sequences confirmed their status as distinct
species. Based on ITS phylogeny and morphology (monopodially branching conidiophores, flexuous to sigmoid ultimate branchlets,
hyaline conidia and lobate haustoria), the two species unequivocally belong to the genus Hyaloperonospora and not to Peronospora to which they were previously assigned. Therefore, two new combinations, Hyaloperonospora drabae and H. norvegica, are proposed. The two taxa are illustrated and compared using the type specimen for H. norvegica and authentic specimens for H. drabae, which is lectotypified. 相似文献
17.
Ae-Young Mo Bora Kwon Seralathan Kamala-Kannan Kui-Jae Lee Byung-Taek Oh Dae-Hyuk Kim Moon-Sik Yang Jin-Hyung Kim Seung-Moon Park 《World journal of microbiology & biotechnology》2010,26(6):1099-1105
Bacteria of the Bacillus species have been reported as an important microorganism in fermented soybean products. In the present study, thirty Bacillus isolates were screened from Meju, a Korean soybean fermentation starter. The comparative analysis of 16S rDNA sequences, 16S-23S internal transcribed spacer
sequences, phenotypic, and biochemical characterizations revealed three phylogenetically distinct groups namely Bacillus atrophaeus,
Bacillus polyfermenticus and Bacillus subtilis. The isolates were assayed for poly-γ-glutamate production and fibrinolytic activity. Among the isolates, B. polyfermenticus exhibited maximum poly-γ-glutamate production and fibrinolytic activity. Moreover, the soybean products fermented by B. polyfermenticus have increased the time taken for coagulation and hemorrhage in mice. The results of the present study clearly indicate the
functional role of B. polyfermenticus in fermented soybean products. 相似文献
18.
The relationship between Sporidiobolus johnsonii and S. salmonicolor was investigated using rDNA sequence data. Two statistically well-supported clades were obtained. One clade included the
type strain of S. johnsonii and the other included the type strain of S. salmonicolor. However, some mating strains of S. salmonicolor were found in the S. johnsonii group. These strains belonged to mating type A2 and were sexually compatible with mating type A1 strains from the S. salmonicolor group. DNA–DNA reassociation values were high within each clade and moderate between the two clades. In the re-investigation
of teliospore germination, we observed that the basidia of S. salmonicolor were two-celled. In S. johnsonii, basidia were not formed and teliospore germination resulted in direct formation of yeast cells. We hypothesize that the
S. johnsonii clade is becoming genetically isolated from the S. salmonicolor group and that a speciation process is presently going on. We suspect that the observed sexual compatibility between strains
of the S. johnsonii and S. salmonicolor groups and the possible genetic flow between the two species has little biological relevance because distinct phenotypes
have been fixed in the two taxa and intermediate (hybrid) sequences for LSU and ITS rDNAs have not been detected.
An erratum to this article can be found at 相似文献
19.
The presence of the anaerobic spore former Clostridium in Arthrospira platensis destined for human consumption is generally not assessed during quality assurance procedures. As this nutraceutical is administered
as complementary medicine to the immunocompromised, this study aimed to investigate the presence of these potential pathogens.
Anaerobic counts performed on tablets from a single manufacturer indicated an excess of 105 CFU/endospores g−1 tablet for three different A. platensis batches. Tests for coliforms for use as “indicators” of pathogens in the tablets were negative. Using classic culture techniques,
five species of Clostridium were isolated. Subsequent use of PCR-denaturing gradient gel electrophoresis (DGGE) fingerprinting of tablets showed a divergent
microbial population, with a predominance of anaerobic endospore formers, including Clostridium. Sequencing of a 1.5 kb 16S rDNA clone library and phylogenetic analyses of prominent operational taxonomic units confirmed
the presence of an additional five Clostridium spp. and other genera in the tablets. A composite molecular ladder, using 16S rRNA DGGE amplicons of 17 representative bacterial
species was constructed to assist in identifying anaerobes present in tablets sourced from three different A. platensis manufacturers. Results indicated that commercial A. platensis preparations were contaminated with potentially hazardous clostridia and other anaerobic species. Results suggest that certain
commercial A. platensis preparations require stringent microbial quality assurance measures to ensure safe use as a nutraceutical for the immunocompromised
and the general public. 相似文献
20.
Ottem KF Nylund A Karlsbakk E Friis-Møller A Krossøy B 《Archives of microbiology》2007,187(5):343-350
A Francisella sp., isolate GM2212T, previously isolated from diseased farmed Atlantic cod Gadus morhua in Norway is characterized. The complete 16S rDNA, 16S–23S intergenic spacer, 23S rDNA, 23S–5S intergenic spacer, 5S rDNA,
FopA, lipoprotein TUL4 (LpnA), malate dehydrogenase and a hypothetical lipoprotein (LpnB) is sequenced and compared with Francisella tularensis and Francisella philomiragia. All these sequences support a close relationship between GM2212T and F. philomiragia. The bacterium grows at 10–25°C with an optimum at about 20°C, a temperature range clearly different from F. tularensis and F. philomiragia. GM2212T is catalase-positive, indole positive, oxidase-negative, do not produce H2S in Triple Sugar Iron agar, and does not hydrolyze gelatin, is resistant to erythromycin and susceptible to ceftazidime,
the latter five characteristics separating it from F. philomiragia. Cysteine enhances growth. Acid is produced from d-glucose, maltose, sucrose (weak) but not from lactose or glycerol. GM2212T grows on both MacConkey agar and in nutrient broth (6% NaCl). The bacterium is resistant to trimethoprim-sulfamethoxazole,
penicillines, cefuroxime and erythromycin; but is susceptible to ceftazidime, tetracycline, gentamicin, ciprofloxacin. Based
on the molecular and phenotypical characteristics, we suggest that this GM2212 isolate, may represent a new species of Francisella. Isolate GM2212T (=CNCM I-3481T = CNCM I-3511T = DSM 18777T). 相似文献