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1.
The phylogenesis of fungi is controversial due to their simple morphology and poor fossilization. Traditional classification supported by morphological studies and physiological traits placed the fission yeasts in one group with ascomycetous yeasts. The rRNA sequence comparisions, however, revealed an enormous evolutionary gap between Saccharomyces and Schizosaccharomyces. As shown in this review, the protein sequences also show a large gap which is almost as large as that separating Schizosaccharomyces from higher animals. Since the two yeasts share features (both cytological and molecular) in common which are also characteristic of ascomycetous fungi, their separation must have taken place later than the sequence differences may suggest. Possible reasons for the paradox are discussed. The sequence data also suggest a slower evolutionary rate in the Schizosaccharomyces lineage than in the Saccharomyces branch. In the fission yeast lineage two ramifications can be supposed. First S. japonicus ( Hasegawaea japonica) branched off, then S. octosporus ( Octosporomyces octosporus) separated from S. pombe. 相似文献
2.
The effect on growth of reducing the water activity ( a
w) of a medium with various solutes has been investigated for 27 strains of fission yeasts ( Schizosaccharomyces). The minimum-tolerated a
w (MTA) was dependent on both the nature of the solute and the species. When the strains of each species were grouped together, the lowest mean MTA values were found with glucose, fructose or glycerol as stressing solutes, being in the range 0.89–0.90 for S. pombe, S. malidevorans, S. octosporus and S. slooffiae, but in the range 0.92–0.94 for S. japonicus. With the non-metabolizable sugars sorbose and xylose and the salts NH 4Cl, KCl, and NaCl, the mean MTA values were in the range 0.96–0.985, except for (1) the single strain of S. slooffiae, which was more tolerant of NH 4Cl and KCl with values of 0.95 and 0.94, respectively, and (2) the strains of S. pombe, S. malidevorans and S. japonicus, which were less tolerant of NaCl with mean values of about 0.99. One strain of each species was examined for intracellular solutes when actively growing in the presence of near-limiting concentrations of stressing solute. With glucose, fructose or glycerol, all five strains contained substantial amounts of glycerol but no other polyol; with the other solutes no glycerol or other polyol was found, except for small amounts of glycerol in strains of S. octosporus and S. slooffiae stressed with NH 4Cl, KCl, or NaCl.Abbreviations
MTA
Minimum-tolerated water activity
-
a
w
water activity
-
YEPG
yeast extract, phosphate, glucose medium 相似文献
3.
The fission yeast genus Schizosaccharomyces contains important model organisms for biological research. In particular, S. pombe is a widely used model eukaryote. So far little is known about the natural and artificial habitats of species in this genus. Finding out where S. pombe and other fission yeast species occur and how they live in their habitats can promote better understanding of their biology. Here we investigate in which substrates S. pombe, S. octosporus, S. osmophilus and S. japonicus are present. To this end about 2100 samples consisting of soil, tree sap fluxes, fresh fruit, dried fruit, honey, cacao beans, molasses and other substrates were analyzed. Effective isolation methods that allow efficient isolation of the above mentioned species were developed. Based on the frequency of isolating different fission yeast species in various substrates and on extensive literature survey, conclusions are drawn on their ecology. The results suggest that the primary habitat of S. pombe and S. octosporus is honeybee honey. Both species were also frequently detected on certain dried fruit like raisins, mango or pineapple to which they could be brought by the honey bees during ripening or during drying. While S. pombe was regularly isolated from grape mash and from fermented raw cacao beans S. octosporus was never isolated from fresh fruit. The main habitat of S. osmophilus seems to be solitary bee beebread. It was rarely isolated from raisins. S. japonicus was mainly found in forest substrates although it occurs on fruit and in fruit fermentations, too. 相似文献
4.
For phylogenetic analysis of the higher fungi, we sequenced the nuclear small subunit rRNA (18S rRNA) gene from Taphrina populina, the type species of the genus Taphrina, and Protomyces lactucae-debilis. The molecular phylogeny inferred from these 2 sequences and 75 sequences from the DNA data bank divided the Ascomycota into three major lineages: the hemiascomycetes, the euascomycetes, and the archiascomycetes, newly described herein. The former two lineages are monophyletic, whereas the archiascomycetes, which originated first and are comprised of Taphrina, Protomyces, Saitoella, Schizosaccharomyces, and Pneumocystis, may not be monophyletic. Among the archiascomycetes, the Taphrina/Protomyces branch is monophyletic. Confirmation of the archiascomycetes as a monophyletic taxonomic class will require comparison of additional genetically defined characters.This work was supported in part by grants 05454030 from the Ministry of Education, Science, and Culture of Japan (to J. S.) and 4369 from the Japan Society for the Promotion of Science Fellowship Programs (to H. N.). 相似文献
5.
Summary The enzymes for inactivating actinomycin D appear to be widely distributed amongst species belonging to the family Actinoplanaceae. Actinomycin D was completely or partially inactivated by cell-free extracts from Actinoplanes missouriensis, Streptosporangium viridogriseum, S. violaceocbromogenes, S. roseum, S. brasiliense, S. albidum, Spirillospora sp., Sp. albida, Kitasatoa kauaiensis, Planobispora longispora, P. rosea, Dactylosporangium aurantiacum, and D. thailandense. No inactivation was obtained with extracts from Amorphosphorangium auranticolor, Ampullariella lobata, Planomonospora parontospora, and P. venezuelensis. Actinomycin lactonase was partially purified by ultracentrifugation, ultrafiltration, and isoelectric focusing from noninduced cells of Actinoplanes missouriensis. The enzyme has a molecular weight of greater than 200,000 daltons and an isoelectric point of 4.3 to 4.4. 相似文献
6.
Cell-free extracts of 93 strains from 23 species and biotypes of Photobacterium, Beneckea, and Vibrio were electrophoresed on polyacrylamide gels and then stained for superoxide dismutase (SOD) activity. All strains exhibited
a single activity band with the exception of Photobacterium leiognathi, which had one major and two minor bands. Strains representative of all three genera were found to have SOD activities that
were sensitive to treatment with H 2O 2, suggesting that they were iron-containing enzymes. Examination of the effect of gel concentration on relative mobility (Rm)
suggested that all the iron-containing SODs had very similar molecular weight. Most species could be distinguished on the
basis of differences in the Rm values of their SODs. Vibrio was readily separable from Beneckea and Photobacterium. A limited electrophoretic analysis of the SODs from Aeromonas, Serratia, Proteus, Erwinia, and other species of terrestrial enterobacteria indicated groupings that were in agreement with previous studies. 相似文献
7.
Protoplasts of auxotrophic mutants isolated from Schizosaccharomyces pombe and Schizosaccharomyces octosporus were fused. The fusion products were capable of complementation and growth on minimal medium, but the morphological observations
suggested a disturbed physiological balance, which was reflected in low viability, osmotic sensitivity, and the formation
of incomplete cell wall. Their asymmetric segregation indicated that Schizosaccharomyces octosporus might be dominant in the fused cells. 相似文献
8.
The ERH gene encodes a highly conserved small nuclear protein with a unique amino acid sequence and three-dimensional structure but unknown function. The gene is present in animals, plants, and protists but to date has only been found in few fungi. Here we report that ERH homologs are also present in all four species from the genus Schizosaccharomyces, S. pombe, S. octosporus, S. cryophilus, and S. japonicus, which, however, are an exception in this respect among Ascomycota and Basidiomycota. The ERH protein sequence is moderately conserved within the genus (58% identity between S. pombe and S.
japonicus), but the intron-rich genes have almost identical intron-exon organizations in all four species. In S. pombe, erh1+ is expressed at a roughly constant level during vegetative growth and adaptation to unfavorable conditions such as nutrient limitation and hyperosmotic stress caused by sorbitol. Erh1p localizes preferentially to the nucleus with the exception of the nucleolus, but is also present in the cytoplasm. Cells lacking erh1+ have an aberrant cell morphology and a comma-like shape when cultured to the stationary phase, and exhibit a delayed recovery from this phase followed by slower growth. Loss of erh1+ in an auxotrophic background results in enhanced arrest in the G1 phase following nutritional stress, and also leads to hypersensitivity to agents inducing hyperosmotic stress (sorbitol), inhibiting DNA replication (hydroxyurea), and destabilizing the plasma membrane (SDS); this hypersensitivity can be abolished by expression of S. pombe erh1+ and, to a lesser extent, S. japonicus erh1+ or human ERH. Erh1p fails to interact with the human Ciz1 and PDIP46/SKAR proteins, known molecular partners of human ERH. Our data suggest that in Schizosaccharomyces sp. erh1+ is non-essential for normal growth and Erh1p could play a role in response to adverse environmental conditions and in cell cycle regulation. 相似文献
9.
A wild type strain of Neurospora crassa produced aerial hyphae and luxuriant conidia in standing culture in low phosphate liquid media. nuc-1 and nuc-2, which have no ability to derepress repressible cyclic phosphodiesterase (cPDase) (3′; 5′-cyclic AMP 5′-nucleotidohydrolase,
EC 3.1.4.17) and several other repressible enzymes, did not form them. Heterocaryon between them restored the abilities not
only to produce aerial hyphae and conidia but also to produce cPDase. Revertants from nuc-1 and a mutant in alkaline phosphatase, pho-2, produced aerial hyphae and conidia in low phosphate condition, whereas a mutant in cPDase, pho-3, produced only a limited amount of them.
In media containing low levels of 2′, 3′-cAMP, the wild type, the revertants from nuc-1, pho-2 and pho-3 produced aerial hyphae and conidia in abundance, whereas in media containing 3′, 5′-cAMP these strains produced no or only
limited amounts of them. In low phosphate media nuc-1, nuc-2 and pho-3 showed higher levels of 3′, 5′-cAMP as compared with those strains which have the ability to derepress cPDase. The cPDase
activities in crude mycelial extracts from nuc-1 and pho-3 grown in low phosphate media were 5.6 and 17.5% of that of pho-2 when assayed for 3′,5′-cAMP at an intracellular level of 2 μM. 相似文献
10.
The genetic frequencies of 9 isozyme loci have been estimated in 23 samples of 4 species of Secale by means of starch gel electrophoresis. The populations of S. silvestre and S. vavilovii were monomorphic and uniform within each species, those of S. montanum and S. cereale were polymorphic for most of the isozyme loci. On the basis of isozyme patterns as well as allelic and genotypic frequencies of isozyme loci, S. silvestre can be distinguished from S. vavilovii, and both from S. cereale and S. montanum; but there is no clear differentiation between the two latter species. Clusters constructed from genetic distances separate S. silvestre and S. vavilovii, whereas S. cereale and S. montanum were grouped together. The isozymatic data presented here, along with cytogenetic and life habit data, agree with the generally admitted existence of 4 species in Secale, and support the relationships suggested by Khush & Stebbins (1961). 相似文献
11.
Mortality of eggs during incubation was estimated for three ocypodid crabs, Scopimera globosa, Ilyoplax pusillus and Macrophthalmus japonicus, and the influence of incubation sites was discussed. These crabs all lived in isolated burrows and fed on sediments during
day time low tide. S. globosa and I. pusillus inhabited the upper intertidal sandflats, whereas M. japonicus inhabited the lower intertidal mudflats. Females of both S. globosa and I. pusillus remained in their plugged burrows without feeding throughout incubation and the mortality of eggs was low despite large broods
relative to body size. On the other hand, females of M. japonicus fed actively on surface mud during incubation and the mortality of eggs was high despiite small broods relative to body size.
In S. globosa and I. pusillus, the ovaries of ovigerous females were small until egg-hatching, whereas in M. japonicus, the ovaries grew rapidly during incubation and females were able to produce consecutive broods. I conclude that incubation
of eggs in burrows may be advantageous in species which inhabit the upper interidal sandflats, even though the crabs cannot
forage during incubation, since otherwise their eggs would be exposed to strong heat stress and desication during the summer.
Furthermore, such species may produce few large broods because of less frequent interruption of feeding than that associated
with production of many small broods. 相似文献
12.
Summary Culture extracts produced by 107 fungi isolated from corn grains were assayed by thin layer chromatography for aflatoxin. Certain isolates of Aspergillus flavus, A. niger, A. parasiticus, A. ruber, A. wentii, Penicillium citrinum, and P. variabile produced aflatoxin. Penicillium frequentans and P. puberulum elaborated this toxin only in trace amounts. Bioassays of extracts from 4 of these fungi showed that only the extract from A. parasiticus was highly toxic. 相似文献
13.
Phage susceptibility pattern and its correlation with lipopolysaccharide (LPS) and plasmid profiles may help in understanding
the phenotypic and genotypic diversity among highly promiscuous group of rhizobia nodulating Sesbania spp.; 43 phages were from two stem-nodulating bacteria of S. rostrata and 16 phages were from root-nodulating bacteria of S. sesban, S. aegyptica and S. rostrata. Phage susceptibility pattern of 38 Sesbania nodulating bacteria was correlated with their LPS rather than plasmid profiles. Different species of bacteria ( A. caulinodans- ORS571, SRS1-3 and Sinorhizobium saheli- SRR907, SRR912) showing distinct LPS subtypes were susceptible to different group of phages. Phages could also discriminate
the strains of Si. saheli (SSR312, SAR610) possessing distinct LPS subtypes. Phages of Si. meliloti (SSR302) were strain-specific. All the strains of R. huautlense having incomplete LPS (insignificant O-chain) were phage-resistant. In in vitro assay, 100% of the phages were adsorbed to
LPS of indicator bacterium or its closely related strain(s) only. These observations suggest the significance of LPS in phage
specificity of Sesbania nodulating rhizobia. Highly specific phages may serve as biological marker for monitoring the susceptible bacterial strains
in culture collections and environment. 相似文献
14.
Summary Several haploid species of Saccharomyces and Schiz. octosporus were shown to ferment sucrose in Durham tubes after a delay of 3 to 4 weeks. Detailed studies were done with a strain of S. rouxii. The delayed fermentation of sucrose was not caused by mutationselection or by inducible enzyme formation, since young glucose
grown cells after drying, freezing, aging or autolysis contained an active sucrase. Cells pretreated by drying or freezing
fermented sucrose nearly as fast as glucose. After autolysis, the sucrase of S. rouxii is only present in the cell debris and not in the autolysate. The use of a heavy inoculum in the van Iterson-Kluyver fermentometer
resulted in a slow, but non-delayed fermentation. Variation in the pH or sucrose concentration had little effect on the delayed
fermentation. It is suggested that after sufficient aging of the cells, the cell wall permeability undergoes a rather abrupt
change, allowing the sucrose to come in contact with the sucrase of the cells. 相似文献
15.
Three strains of Madurella mycetomi, two of M. grisea, and two of Rhinocladiella mansonii have been studied for possible differences in growth requirements which might be used for distinguishing these species.
Under the experimental conditions, an incubation temperature of 37C suited M. mycetomi about as well as 30C. R. mansonii grew less well at 37C than at 30C, and M. grisea did not grow at the higher temperature.
M. grisea and R. mansonii further differed from M. mycetomi in that they required thiamine for growth.
The pH tolerance of all the strains was very wide.
Asparagine and potassium nitrate were readily utilized by all the strains, but ammonium salts were not. Urea was poorly used
by M. mycetomi; the other species did not use it.
A possible relationship of M. grisea and R. mansonii is discussed. 相似文献
16.
The ability of several continuous tick cell culture lines to support growth of tickborne spiroplasmas (helical, wall-less prokaryotes in the class Mollicutes) was assessed. Seven triturates, prepared from pools of Ixodes pacificus ticks naturally infected with the Spiroplasma sp. (group VI) organism, were retrieved from frozen (–70°C) storage and passaged in three distinct tick cell lines, in antibiotic-free tick cell culture medium alone, or in spiroplasma culture medium (SP-4 formulation). Six spiroplasma strains were recovered in the RML-19 cell line from Dermacentor variabilis, and five isolations were made in another cell line (RML-15) from this tick species. None was recovered in a Rhipicephalus sanguineus cell line (RML-23), in tick cell culture medium, or in SP-4 broth medium. One of the spiroplasma isolates (Y43) was maintained through four consecutive weekly refeedings of the D. variabilis cell line and for three feedings of R. sanguineus cells, where numbers of spiroplasmas in cell supernatants reached levels comparable to those obtained in the SP-4 medium.A laboratory-adapted strain (SMCA) of Spiroplasma mirum, a second helical mollicute of tick origin (the suckling mouse cataract agent), grew in three tick cell lines (RML-15, RML-23, and RML-16 cells from D. parumapertus), in three mosquito cell lines (from Aedes albopictus, Ae. aegypti, and Culex quinquefasciatus), and in both cell culture medium alone and in SP-4 medium. The organisms survived for 1–2 weeks, but failed to multiply, in cell lines from C. tritaeniorhynchus, Antheraea eucalypti, or Xenopus laevis. Some evidence of cytopathic effect of S. mirum on tick cell lines was seen, although growth of the organism in mosquito cell cultures was not associated with cell toxicity. The use of arthropod cell lines appears to have value in the primary isolation of arthropod- or insect-derived mollicutes and for the study of cytopathogenicity of these wall-less prokaryotes. 相似文献
17.
The fungus associated with the Japanese horntail, Urocerus japonicus, in Kochi, Kagawa and Ehime Prefectures was studied. Cultures isolated from the mycangia of 113 adult females of the horntail
showed the same cultural characteristics. Four of basidiocarps found on felled logs of Cryptomeria japonica were identifieds as Amylostereum laevigatum based on morphological characteristics. This was the first record of A. laevigatum from Japan. The cultures isolated from the basidiocarps had the same cultural characteristics as those from the mycangia
of U. japonicus. One mycangial isolate produced basidiocarps on artificially inoculated stem segments of Cr. japonica after a 6-mo incubation and was identified as A. laevigatum. One isolate from the basidiocarps of A. laevigatum and one from the mycangium of U. japonicus were artificially inoculated into five trees each of Chamaecyparis obtusa and Cr. japonica. The wood of all inoculated trees showed discoloration, with no difference in shape and pattern of discoloration between
the two isolates. The inoculated fungi were reisolated from the areas of discoloration in the inoculated trees. 相似文献
18.
The fission yeasts are members of the fungal order Schizosaccharomycetales, a candidate deep-diverging group within Ascomycota. Although a great deal of molecular information is available from Schizosaccharomyces pombe, a model eukaryote, very little is available from other members of this group. In order to better characterize mitochondrial genome evolution in this fungal lineage, the mitochondrial DNA (mtDNA) of two additional fission yeasts, Schizosaccharomyces octosporus and Schizosaccharomyces japonicus var. japonicus, was sequenced. Whereas the mtDNA of S.pombe is only 19 431 bp, the mtDNA of S.octosporus is 44 227 bp, and that of S.japonicus var. japonicus is over 80 kb. The size variation of these mtDNAs is due largely to non-coding regions. The gene content in the latter two mtDNAs is almost identical to that of the completely sequenced S.pombe mtDNA, which encodes 25 tRNA species, the large and small mitochondrial ribosomal RNAs ( rnl and rns), the RNA component of mitochondrial RNaseP ( rnpB), mitochondrial small subunit ribosomal protein 3 ( rps3), cytochrome oxidase subunits 1, 2 and 3 ( cox1, cox2 and cox3) and ATP-synthase subunits 6, 8 and 9 ( atp6, atp8 and atp9). However, trnI2(cau) (C modified to lysidine) is absent in the S.octosporus mtDNA, as are corresponding ATA codons in its protein-coding genes, and rps3 and rnpB are not found in the mtDNA of S.japonicus var. japonicus. The mtDNA of S.octosporus contains five double hairpin elements, the first report of these elements in an ascomycete. This study provides further evidence in favor of the mobility of these elements, and supports their role in mitochondrial genome rearrangement. The results of our phylogenetic analysis support the monophyly of the Schizosaccharomycetales, but question their grouping within the Archiascomycota. 相似文献
19.
Summary Electrophoretic comparisons have been made for 24 enzymes in the Bergerac and Bristol strains of Caenorhabditis elegans and the related species, Caenorhabditis briggsae. No variation was detected between the two strains of C. elegans. In contrast, the two species, C. elegans and C. briggsae exhibited electrophoretic differences in 22 of 24 enzymes. A consensus 5S rRNA sequence was determined for C. elegans and found to be identical to that from C. briggsae. By analogy with other species with relatively well established fossil records it can be inferred that the time of divergence between the two nematode species is probably in the tens of millions of years.The limited anatomical evolution during a time period in which proteins undergo extensive changes supports the hypothesis that anatomical evolution is not dependent on overall protein changes. 相似文献
20.
Relationships between 9 Oryza species, covering 6 different genomes, have been studied using hybridization and nucleotide sequence information from the 5S Dna locus. Four to five units of the major size class of 5S DNA in each species, 55 units in all, were cloned and sequenced. Both hybridization and sequence data confirmed the basic differences between the A and B, C, D genome species suggested by morphological and cytological data. The 5S DNA units of the A genome species were very similar, as were the ones from the B, C, and D genome-containing species. The 5S DNA of O. australiensis (E genome) grouped with the B, C, D cluster, while the units of O. brachyantha (F genome) were quite different and grouped away from all other species. 5S DNA units from O. minuta, O. latifolia, O. australiensis, and O. brachyantha hybridized strongly, and preferentially, to the genomic DNA from which the units were isolated and hence could be useful as species/genome specific probes. The 5S DNA units from O. sativa, O. nivara, and O. rufipogon provided A genome-specific probes as they hybridized preferentially to A genome DNA. The units from O. punctata and O. officinalis displayed weaker preferential hybridization to O. punctata DNA, possibly reflecting their shared genome (C genome). 相似文献
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