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1.
2.
A new species of Hirsutella, H. proturicola, isolated from a subterranean proturan (Baculentulus densus; Protura, Hexapoda), is described and illustrated. Hirsutella proturicola is characterized by producing monoblastic phialides of 24–51.5 × 2.5–5 μm with a slightly roughened neck, fusiform and curved conidia of 9–18 × 2.5–4 μm that have a truncate base and a papillate projection often capped with sheath-like mucilage, and pluricellular, globose to subglobose chlamydospores of 21–48 × 21–41.5 μm. This species is morphologically and phylogenetically close to H. rostrata, an acaropathogenic species, but can be distinguished from the size of the phialides and the size and shape of the conidia.  相似文献   

3.
Haptoglossa spp. (Lagenidiales, Oomycetes) have been known to parasitize microscopic animals by means of a "gun" cell that shoots an infection cell, named the sporidium, into the body of the animal. A thallus grown from the sporidium changes into a zoosporangium at maturation to produce a number of zoospores that encyst after a swarming period, and the resulting cysts germinate to produce gun cells. In Haptoglossa zoospora, endoparasitic in nematodes, the cysts of primary zoospores that swam for about 5 min did not develop gun cells but produced secondary zoospores that swam for about 3 h. After encystment of the secondary zoospores, each secondary cyst germinated to produce a gun cell. In the present study, the secondary zoospores of the genus Haptoglossa could be recorded with a videocassette recorder for the first time. The videocassette recording also revealed the infection of a nematodes by H. zoospora and H. heterospora to be composed of two steps of injection of a sporidium by the gun cell, in which the gun cell came in contact with the cuticle of a nematode and produced a spherical adhesorium on the tip of the cell in 0.07–0.1 s in both species. The adhesorium was ∼2 μm in H. zoospora and ∼4 μm in H. heterospora. When the adhesorium infiated to full size, it shot the sporidium into the nematode's body in 0.5–0.65 s and in 0.2–0.5 (or rarely 1.0) s in H. zoospora and H. heterospora, respectively. After shooting, the empty gun cell with an empty cyst case was separated from the cuticle immediately in both species. Received: October 3, 2001 / Accepted: December 13, 2001  相似文献   

4.
We used a combination of molecular-phylogenetic inference of 82 ITS rDNA sequences and anatomical approach to describe three new west African thelephoroid species, namely Tomentella afrostuposa, T. guineensis and T. guinkoi. Anatomically, T. afrostuposa is reminiscent of T. stuposa with globose to broadly ellipsoid large basidiospores of 8–14 μm, long aculei of up to 3 μm and prominent apiculi of 2 μm width. Molecular-phylogenetically, it falls within the T. stuposa complex. However, T. afrostuposa deviates by at least 7.80–10.74% from T. stuposa in regard with the ITS rDNA sequences. Tomentella guineensis is characterised by long (up to 85 μm) utriform basidia, the presence of reniform basidiospores in lateral view (up to 9 μm) with aculei not exceeding 1 μm and a strong cyanescent reaction of the subhymenial hyphae and basidia in 2.5% KOH. It forms a sister species of the newly described species Tomentella maroana; however, deviating from the last species by at least 9.75–10.04%. The very short, inflated (up to 14 μm) and thick-walled septate (septa up to 1.5 μm) subhymenial hyphae combined with ellipsoid basidiospores (up to 8 μm) and short aculei not exceeding 0.5 μm characterise Tomentella guinkoi. Anatomically, T. guinkoi recalls T. ellisii. Genetic distance between both species ranges from 12.67 to 13.73% according to ITS rDNA sequences analyses. Tomentella guinkoi forms a sister species of the group composed of T. ellisii, T. hjortstamiana and T. pisoniae. Detailed anatomical comparisons between the newly described species and their close relatives are given.  相似文献   

5.
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   

6.
In this work, the variability of spo0A gene in the genus Geobacillus and applicability of this gene for the taxonomy within this genus were evaluated. The protein Spo0A is the master regulator of the endospore-forming process in the all endospore-forming bacteria. Geobacillus genus-specific primers GEOSPO were designed based on the sequences of Geobacillus spo0A gene available through the public databases. Inter and intraspecific variability of Geobacillus spo0A gene was determined after sequencing of the GEOSPO-PCR products. Geobacillus spo0A sequence analysis showed that three species—Geobacillus thermodenitrificans, G. stearothermophilus, and G. jurassicus—could be easily identified. Similarity between the sequences of these species and the other species were in the range of 83.3%–92.0%. In contrast, intraspecific similarity of G. thermodenitrificans and G. stearothermophilus was high—above 99.0%. Similarity of spo0A sequences of G. subterraneus–G. uzenensis species cluster also matched this interval. Intercluster similarity between G. lituanicus–G. thermoleovorans–G. kaustophilus–G. vulcani and G. thermocatenulatus–G. gargensisG. caldoxylosilyticus–G. toebii–G. thermoglucosidasius species clusters, as well as interspecific similarity within these two clusters was in the range of the intraspecific similarity determined for G. thermodenitrificans and G. stearothermophilus. It was also determined that spo0A cannot be used as the phylogenetic marker for the genus Geobacillus.  相似文献   

7.
Choi YJ  Hong SB  Shin HD 《Mycopathologia》2007,164(2):91-95
Bremia lactucae Regel (Chromista, Peronosporaceae) is an economically destructive pathogen, which causes downy mildew disease on lettuce (Lactuca sativa L.) worldwide. The ribosomal internal transcribed spacer (ITS) of Bremia lactucae isolates was analyzed for the first time. The ITS region of lettuce downy mildew was observed to have a size of 2458 bp; thereby, having one of the longest ITS sizes recorded to date. The majority of the extremely large sized ITS2 length of 2086 was attributed to the additional presences of nine repetitive elements with lengths of 179–194 bp, which between them shared the low homology of 48–69%. Comparison of the ITS2 sequences with the B. lactucae isolates from other host plants showed that isolates present on Lactuca sativa were distinct from those on L. indica var. laciniata, as well as Hemistepta and Youngia. We suggest the high degree of sequence heterogeneity exhibited in the ITS2 region of B. lactucae may warrant the specific detection and diagnosis of this destructive pathogen or its division into several distinct species.  相似文献   

8.
Leafy spurge (Euphorbia esula L.) is a perennial, invasive weed used as a model to study invasive plant behavior, because molecular tools (such as a deep expressed sequence tag database and deoxyribonucleic acid microarrays) have been developed for this species. However, the lack of effective in vitro regeneration and genetic transformation systems has hampered molecular approaches to study leafy spurge. In this study, we describe an efficient in vitro regeneration system. Three highly regenerative lines were selected by screening the in vitro regeneration capabilities of stem explants of 162 seedlings. The effects of various culture conditions on in vitro regeneration were then evaluated based on explant competence to form calluses and shoots. High rates of shoot regeneration can be obtained using a growth medium containing 1× woody plant basal medium and 1× Murashige and Skoog (MS) basal salts, 1× MS vitamins, 1.11 μM 6-benzylaminopurine, 1.97 μM indole-3-butyric acid, and 3% sucrose, pH 5.6–5.8. After 30 d culture, multiple shoots formed either directly from the stem or indirectly from the callus. This method is a requisite for the development of genetic transformation systems for leafy spurge and may be used to develop in vitro regeneration techniques for other species in the Euphorbiaceae.  相似文献   

9.
Establishment, maintenance, regeneration, and transformation of somatic embryos by both direct and indirect means (callus-mediated) was achieved for Bixa orellana, a tropical plant whose seeds produce commercially edible ‘annatto pigment,’ which mainly constitutes an apocarotenoid called bixin. Callus-mediated methodology was found to be efficient in producing a greater number of embryos in a short time. The maximum of 28 somatic embryos were produced in 16–18 weeks when immature zygotic embryonic stalks were inoculated onto Murashige and Skoog (MS) medium containing B5 vitamins supplemented with 0.44 μM benzyladenine (BA), 0.054 μM α-naphthaleneacetic acid (NAA), 2.89 μM gibberellic acid (GA3), 0.02 μM triiodobenzoic acid (TIBA), and 0.011 μM triacontanol (TRIA). Callus initiation from hypocotyl explants was obtained on MS medium supplemented with 1.07–2.14 μM NAA and 10.2 μM BA. In 3 months, somatic embryos were produced when callus was inoculated onto MS medium supplemented with 4.44 μM BA, 40 μM AgNO3, and 0.011 μM TRIA. Somatic embryos were efficiently regenerated on MS basal solid and liquid media supplemented with 0.44–4.4 μM BA, 0.54–2.69 μM NAA, 4.92 μM 2iP, 2.1 μM calcium d-pantothenate, 0.21 μM biotin, 227.7 μM cysteine HCl monohydrate, and 108.6 μM adenine sulfate. Agrobacterium tumefaciens GV 3101 harboring pCAMBIA 1305.2 binary vector-mediated stable transformation of somatic embryos exhibited a transformation frequency of 2.56%. As somatic embryogenesis in any perennial system is useful in terms of both commercial and scientific nature, this somatic embryo-based transformation protocol for the commercially important dye-yielding tropical plant B. orellana is useful for its improvement through genetic engineering.  相似文献   

10.
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   

11.
Humulus japonicus in communities of Miscanthus sacchariflorus and Phragmites australis can grow large enough to overtop other species in the Amsa-dong floodplain. Because of strong winds and the weight of Humulus, plants of M. sacchariflorus and P. australis fell in mid-August and were subject to decomposition under its dense shading. To assess the effects of H. japonicus on nutrient cycling in these communities, we collected fresh samples of M. sacchariflorus and P. australis in litterbags and decomposed them under H. japonicus for 9 months, beginning in August. Biomass and organic contents from M. sacchariflorus during this incubation period were 49–51% and 44–48%, whereas those of P. australis were 49–61% and 32–52%, respectively. Their annual k values were 1.61–1.74 and 1.46–3.54, respectively. Initial N concentrations in M. sacchariflorus and P. australis were 13 and 20 mg g−1, while C:N ratios were 31 and 21, respectively. These results indicate that H. japonicus is responsible for the collapse of M. sacchariflorus and P. australis in August and also accelerates their nutrient cycling through rapid decomposition, thereby increasing nutrient circulation in floodplains.  相似文献   

12.
13.
Echinorhynchus hexagrammi Baeva, 1965 is redescribed on the basis of specimens collected from the saffron cod Eleginus gracilis (Tilesius) in Akkeshi Bay (western North Pacific) off Hokkaido, Japan. Eighteen museum specimens deposited as E. salmonis Müller, 1784 from Japanese coastal waters were also re-examined and re-identified as E. hexagrammi. Hexagrammos stelleri Tilesius, Hemitripterus villosus (Pallas), Podothecus sachi (Jordan & Snyder), Sebastes oblongus Günther and Verasper moseri Jordan & Gilbert are recognised as new hosts for E. hexagrammi. This acanthocephalan can be distinguished from three morphologically similar species, E. gadi Zoega in Müller, 1776, E. laurentianus Ronald, 1957 and E. salmonis, by the possession of the following characters: 12–16 (usually 14) rows of hook on the proboscis, a proboscis width of 170–240 μm in males and 195–270 μm in females, a hook root length of 35–45 μm in males and 40–50 μm in females, and linearly or almost linearly arranged cement glands in males.  相似文献   

14.
Pityopsis ruthii is an endangered herbaceous perennial species from the United States. In vitro multiplication of this species can be valuable for germplasm conservation. Flower receptacles of P. ruthii were cultured on Murashige and Skoog medium (MS) supplemented with 11.4 μM indole-3-acetic acid (IAA) in combination with 2.2, 4.4 or 8.8 μM 6-benzyladenine (BA). Shoots were visible within 14–28 days and three plants were successfully rooted on MS medium supplemented with 5.7 μM IAA. A two tailed t-test for paired-variates revealed that shoot regeneration on MS medium amended with 11.4 μM IAA and 2.2 μM BA was significantly higher (P < 0.05) than on other treatments. Leaf explants were also cultured on MS not supplemented with growth regulators or supplemented with 11.4 μM IAA in combination with 0, 2.2, 4.4 or 8.8 μM BA. Shoots were visible within 21–35 days and one plant was successfully rooted on MS medium supplemented with 5.4 μM NAA. Shoot regeneration on MS medium augmented with 11.4 μM IAA and 2.2 μM BA was significantly higher (P < 0.05) than the other treatments according to analysis of variance (ANOVA) with a rank transformation. Hyperhydricity and rooting of shoots was problematic for explants derived from flower receptacles and leaf tissue, but viable plants were regenerated using both explants sources indicating the potential role for micropropagation in the ex situ conservation of the species.  相似文献   

15.
Halophilic archaeal strains R26T and R22 were isolated from the brown alga Laminaria produced at Dalian, Liaoning Province, China. Cells from the two strains were pleomorphic rods and Gram negative, and colonies were red pigmented. Strains R26T and R22 were able to grow at 20–50°C (optimum 37°C) in 1.4–5.1 M NaCl (optimum 3.1–4.3 M) at pH 5.5–9.5 (optimum pH 8.0–8.5) and neither strain required Mg2+ for growth. Cells lyse in distilled water and the minimum NaCl concentration required to prevent cell lysis was 8% (w/v) for strain R26T and 12% (w/v) for strain R22. The major polar lipids of the two strains were phosphatidylglycerol, phosphatidylglycerol phosphate methyl ester and minor phosphatidylglycerol sulfate; glycolipids were not detected. Phylogenetic analyses based on 16S rRNA genes and rpoB′ genes revealed that strains R26T and R22 formed a distinct clade with the closest relative, Natronoarchaeum mannanilyticum. The DNA G+C content of strains R26T and R22 was 65.8 and 66.4 mol%, respectively. The DNA–DNA hybridization value between strains R26T and R22 was 89%. The phenotypic, chemotaxonomic and phylogenetic properties suggest that the strains R26T and R22 represent a novel species in a new genus within the family Halobacteriaceae, for which the name Salinarchaeum laminariae gen. nov., sp. nov. is proposed. The type strain is R26T (type strain R26T = CGMCC 1.10590T = JCM 17267T, reference strain R22 = CGMCC 1.10589).  相似文献   

16.
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   

17.
The genus Dierama comprises plants with a potential to be developed as ornamentals. D. erectum seeds were decontaminated and germinated on 1/10th strength Murashige and Skoog (Physiol Plant 15:473–497, 1962) (MS) media without plant growth regulators or sucrose. In an experiment investigating the effects of 6-benzyladenine (BA), meta-Topolin (mT), kinetin (KIN) and zeatin (Z) with or without α-naphthaleneacetic acid (NAA), the highest shoot number per hypocotyl (4.20 ± 0.51) was obtained from MS medium supplemented with 1.0 μM Z after 8 weeks. This was followed by a combination of 2.0 μM KIN and 2.0 μM NAA with 3.67 ± 0.81 shoots per explant. BA treatments produced 3.20 ± 0.22 shoots per hypocotyl explant when 2.0 μM was combined with 1.0 μM NAA, while mT gave 3.09 ± 0.99 shoots per explant when 2.0 μM mT was combined with 2.0 μM NAA. Adventitious shoot regeneration was optimised when shoots were grown under a 16-h photoperiod at 100 μmol m−2 s−1 on MS medium supplemented with 1.0 μM BA. This resulted in an average of 12.73 ± 1.03 shoots per hypocotyl explant. Various concentrations of ancymidol, activated charcoal and sucrose did not promote in vitro corm formation of this species. Plants rooted successfully after 8 weeks on MS medium supplemented with 1.0 μM indole-3-butyric acid (IBA) and had an average root number of 2.73 ± 0.40. After 2 months of acclimatisation, plants had formed corms. The largest corms (of diameter 0.45 ± 0.03 cm) were produced in plants pre-treated with 0.5 μM IBA. The highest plant survival percentage of 73% was also associated with this treatment.  相似文献   

18.
19.
By applying polyethylene glycol (PEG)-mediated protoplast fusion, the first somatic hybrids were obtained between Cyclamen persicum (2n = 2x = 48) and C. coum (2n = 2x = 30)—two species that cannot be combined by cross breeding. Heterofusion was detected by double fluorescent staining with fluorescein diacetate and scopoletin. The highest heterofusion frequencies (of about 5%) resulted from a protocol using a protoplast density of 1 × 106/mL and 40% PEG. The DNA content of C. coum was estimated for the first time by propidium iodide staining to be 14.7 pg/2C and was 4.6 times higher than that of C. persicum. Among 200 in vitro plantlets regenerated from fusion experiments, most resembled the C. coum parent, whereas only 5 plants showed typical C. persicum phenotypes and 46 had a deviating morphology. By flow cytometry, six putative somatic hybrids were identified. A species-specific DNA marker was developed based on the sequence of the 5.8S gene in the ribosomal nuclear DNA and its flanking internal transcribed spacers ITS1 and ITS2. The hybrid status of only one plant could be verified by the species-specific DNA marker as well as sequencing of the amplification product. RAPD markers turned out to be less informative and applicable for hybrid identification, as no clear additivity of the parental marker bands was observed. Chromosome counting in root tips of four hybrids revealed the presence of the 30 C. coum chromosomes and 2–41 additional ones indicating elimination of C. persicum chromosomes.  相似文献   

20.
The genus Chromobacterium encompasses free-living Gram-negative bacteria. Until 2007, the genus consisted of only one species but six species are now recognized. Chromobacterium violaceum is the type species of the genus and is commonly found in soil and water in tropical and sub-tropical regions. We have investigated a collection of 111 isolates displaying violet pigmentation from undisturbed aquatic and soil environments from Brazilian Cerrado ecosystem. The 16S rRNA gene phylogeny revealed that all isolates were allocated in a monophyletic cluster inside the Chromobacterium genus and formed few clusters related most closely with Chromobacterium piscinae. The two sets of isolates from water and soil were analyzed by the repetitive extragenic palindromic (rep)-PCR genomic fingerprinting technique using a BOX-AR1 primer. The antimicrobial susceptibility and the different carbon sources utilized by these isolates were also investigated. Physiological profiles of the isolates generated by BIOLOG GN2 plates showed great versatility in the substrate utilization, much higher than the C. violaceum ATCC 12472. All isolates exhibited a high minimum inhibitory concentration (MIC) to ampicillin (MIC > 512 μg/ml) and were inhibited by ciprofloxacin, tetracycline and mercury at the lowest concentration tested (MIC < 2 μg/ml). Thirteen BOX-PCR band patterns were identified from 33 individual fingerprints. Eleven patterns provided evidence for endemic distributions. Antimicrobial susceptibility and BOX-PCR fingerprint clustering showed a clear distinction between Chromobacterium isolates from the water and soil. The results suggested that microenvironment barriers such as water and soil can play an important role in the periodic selection and diversification of Chromobacterium population ecotypes.  相似文献   

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