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1.
The contraction of Stentor and Blepharisma, in response to mechanical and electrical stimulation and of Spirostomum in response to mechanical stimulation is described. All three species respond to electrical stimulation by contraction of the cytoplasm, beginning at the anodal end regardless of orientation of the animal. The differences in contractile ability and shapes during contraction are discussed in relation to body form and microanatomy. Stentor and Spirostomum also respond to mechanical stimulation. Dropping a weight on the slide causes contraction of the whole body of Spirostomum, but not of Stentor. Stimulation of the oral region of Stentor by means of a vibrating needle causes a contraction of the entire body, but this sensitivity is limited to the oral region. Blepharisma does not respond to mechanical stimulation. Spirostomum and Stentor undergo rapid spontaneous contractions, but Blepharisma does not contract spontaneously. 相似文献
2.
J. J. Martínez-Sánchez A. Marín J. M. Herranz P. Ferrandis J. De las Heras 《Plant Ecology》1995,116(1):69-72
Seeds ofPinus halepensis andPinus pinaster subsp.pinaster were subjected to four heat treatments (90, 110, 150 and 200 °C) for 1 and 5 min to investigate their tolerances to high temperatures resulting from fires. Another group of seeds of each species were not heated and considered as a control. Information on responses of seeds to high temperatures would help to determine whether or not the species are pyrophytes. Heating for 1 min at all temperatures did not affect the average germination ofPinus halepensis seeds whereas that ofP. pinaster subsp.pinaster seeds was decreased significantly when they were heated to 200 ° C. HoweverP. pinaster seeds were more resistant than that ofP. halepensis when heat treatment was 150 °C for 5 min. Data obtained also indicated that, in general,P. halepensis andP. pinaster subsp.pinaster seed germination is not favoured by a temperature increase than can be reached in soils during a fire. Thus, the species are not pyrophytes but colonizers of burnt sites. 相似文献
3.
《Journal of bryology》2013,35(4):581-587
Abstract P. andrewsii appears to be widespread in the arctic regions of the U.S.S.R. and also in mountains of southern Siberia, the Altai Mountains. Except in the mountains of Central and Northern Europe the range of P. andrewsii does not overlap with P. annotina and P. camptotrachela. 相似文献
4.
Burkhead Karen D. Peterson Stephen W. Bolen Paul L. 《Journal of industrial microbiology & biotechnology》1994,13(4):233-237
Summary Six hundred and seventy microorganisms were screened for the ability to perform stereoselective aromatic hydroxylation reactions of industrial significance, using aniline as a model substrate. TLC and HPLC analyses with diode array detection were used to identify and characterize hydroxylase activities. Of 79 cultures belonging to the speciesAspergillus alliaceus, A. albertensis, andA. terreus, 26 strains produced 2-aminophenol. Thirty strains were able to hydroxylate aniline in thepara position. Five strains ofA. terreus produced an unidentified phenolic compound in high yield.The mention of firm names or trade products does not imply that they are endorsed or recommended by the US Department of Agriculture over other firms or similar products not mentioned. 相似文献
5.
E. G. Pringsheim 《Archives of microbiology》1965,50(4):401-413
Zusammenfassung
Oscillatoria agardhii var. suspensa n. var. ist ein Süßwasser-Planktont, der O. agardhii nahe steht, sich aber durch geringere Abmessungen und den Bau der Trichom-Enden unterscheidet. Sie wurde durch Waschen von anderen Organismen befreit, was bisher noch bei keiner Cyanophycee gelungen war.Die Art lebt im Wasser schwebend. Nur in alten Kulturen sammelt sie sich an der Oberfläche an.
O. agardhii var. suspensa ist streng photo-autotroph und macht von organischen Nährstoffen keinen Gebrauch. Sie ist sogar sehr empfindlich gegen manche von ihnen, besonders gegen Glucose (aber nicht gegen andere Zucker), die schon in geringen Konzentrationen die Vermehrung unterdrückt.Die weißlich-grüne Farbe der Art wird durch die Pseudovacuolen bewirkt; der Chlorophyllgehalt ist aber nicht geringer als der von anderen Cyanophyceen, die tief blaugrün aussehen.
Summary Oscillatoria agardhii var. suspensa n. var. is a freshwater planktont allied to O. agardhii but differing in smaller dimensions and the shape of the trichome-ends. It was freed from other organisms by the washing procedure, a technique that had not yet been successful in any member of the Cyanophyceae.The organism lives suspended in the water except in old cultures when it tends to accumulate near the surface. O. agardhii var. suspensa is strictly photo-autotrophic not utilizing any organic nutrients and even to some of them very sensitive, particularly to glucose (though not to other sugars) which prevents growth at minute concentrations.The whitish green hue of the species is due to pseudovacuoles while the content of chlorophyll is not lower than that of Cyanophycean species appearing deep blue-green to the eye.相似文献
6.
Proteases of the genus Bacillus. II. Alkaline proteases 总被引:5,自引:0,他引:5
The alkaline proteases of B. subtilis NRRL B3411, B. pumilis, and B. licheniformis have been isolated by fractionation followed by ion exchange chromatography and their homogeneity demonstrated. General enzyme properties of the B. sublitis NRRL B3411 alkaline protease have been studied and attempts made to differentiate a group of alkaline proteases. It is clear that the alkaline proteases known as Subtilisins or Subtilopeptidases are not, exclusive to B. subtilis but are common to many Bacilli and therefore the generic name Bacillopeptidases has been proposed. It is clear too that on the basis of the effect of pH on activity, amino acid composition, esterase activity, and immunological cross-reactions the Bacillopeptidases can be divided into two groups or types: (a) Bacillopcptidase A (Subtilisin A or Subtilopeptidase A) which includes Subtilisin Carlsberg, B. licheniformis, and B. pumilis alkaline proteases; ( b ) Bacillopeptidase B (Subtilisin B or Subtilopeptidase B) which includes B subtilis NRRL B3411, Subtilisin Novo, Subtilisin BPN' (Nagarse), alkaline protease Daiwa Kasei, and (probably) B. subtilis var. amylosacchariticus. At present, no further differentiation is possible and whether or not the enzymes within group A or B are identical remains an open question. Methods for examination of crude enzyme mixtures or fermentation beers are described and from the examination of a number of crude enzymes and fermentation beers it appears that organisms producing Bacillopeptidase A do not produce neutral protease or amylase, while organisms producing Bacillopeptidase B produce a neutral protease and amylase as well. 相似文献
7.
Beninweck Ndambi Abuelgasim Elzein Annerose Heller 《Biocontrol Science and Technology》2012,22(2):135-150
Fusarium oxysporum f. sp. strigae (Foxy 2) is a mycoherbicide against Striga hermonthica. To ensure the safe use of this biocontrol agent, and as part of the risk assessment, this study was aimed at providing cytological evidence that Foxy 2 does not possess pathogenic behavior towards the non-target host sorghum. Therefore, we compared the infection processes and sorghum root tissue reactions towards the pathogenic F. proliferatum to that of Foxy 2 using light- and transmission electron microscopy. Given that during the growth process, hyphae could get into the central cylinder, tissue specific reactions of sorghum to Foxy 2 were also investigated by wounding the roots (exposing the vascular system), and testing for proliferation of hyphae within the vessels. Results showed that 2 weeks after sowing, F. proliferatum had invaded and destroyed all cell types including the central cylinder while Foxy 2 hyphae were located around the outer endodermal layer and were not able to penetrate the latter. There was an increase in blue autoflourescence in the central cylinder and especially the endodermis, probably due to increased phenolics in Foxy 2 infected roots which was not the case for F. proliferatum. This might contribute to the inability of Foxy 2 to penetrate the endodermis. Transmission electron microscopy showed extensive degradation of endodermis and vessel walls into thin translucent layers by F. proliferatum but not by Foxy 2. In the mechanically wounded and infected roots, Foxy 2 could invade the central cylinder close to the wound but was not identified a few millimeters away from the wound. This implies that it was not able to grow within or destroy the central cylinder even when already present within it; probably due to the observed increased phenolics. Thus, exposure of the vascular system did not serve as a route for the invasion of Foxy 2 which therefore could not further cause tracheomycosis. Therefore, Foxy 2 could be seen as a fungus well suited for biocontrol. 相似文献
8.
9.
ROBIN M. OVERSTREET WILLIAM E. HAWKINS JOHN W. FOURNIE 《The Journal of eukaryotic microbiology》1984,31(2):332-339
Calyptospora n. g. was erected for Eimeria funduli because the sporocyst of that species lacks Stieda and sub-Stieda bodies, has a veil supported by sporopodia, and has an anterior apical opening. A suture may be present, but it does not completely divide the sporocyst into two valves. Because C. funduli has an obligatory invertebrate intermediate host, we established Calyptosporidae n. fam. to accommodate Calyptospora and tentatively to accept Goussia. A new subgenus, Plagula, is erected for species of Goussia with a sporocystic veil not supported by sporopodia. We consider the family more primitive than Eimeriidae, Sarcocystidae, and possibly Lankesterellidae. 相似文献
10.
A new species is added to the monotypic African genus Djinga. Djinga cheekii Ghogue, Huber & Rutish. (Podostemaceae) is described as a new species from Cameroon (Littoral Province) and its morphological affinities and conservation status are assessed. The main distinguishing characters are: stamens 2 (not 1 as in D. felicis), flower buds inside spathella strongly inclined (not only slightly inclined as in D. felicis), and stems lacking or only up to 6 mm long (not up to > 6 cm as in D. felicis). A molecular analysis revealed that D. cheekii is sister to D. felicis, and both together are sister to Ledermanniella linearifolia and L. pusilla which show completely inverted flower buds inside the spathella, as typical for the large and still artificial genus Ledermanniella. 相似文献
11.
Trois Especes Nouvelles d'Ophryoglenes: O. gelifera n. sp., O. mucosa n. sp., O. multimicronucleata n. sp. (Cilies Holotriches Peniculiens) 总被引:1,自引:0,他引:1
SYNOPSIS. A previous study with P. de Puytorac on O. bacterocaryon(3) has shown the methods of studying this Ciliate and has specified the general and buccal morphology, the morphogenesis, and the biology of vegetative individuals (theront, trophont, tomont, tomites) of this species. Three species we are describing now offer numerous common features with O. bacterocaryon. We consider them as the proper characters of genus Ophryoglena and we only insist on the specific particularities of O. gelifera, O. mucosa and O. multimicronucleata. O. gelifera is a large Ophryoglene differing from the others by a slightly asymetric, curved, spindle-shaped theront; the ellipsoidal tomont secretes abundant and clear jelly. The theront possesses one thick spindle-shaped macronucleus, one voluminous spherical micronucleus, fitting with the macronucleus. Its somatic infraciliature is dense, its buccal infraciliature is characteristic, especially in the shape of peniculus P1. This species cannot be mistaken for O. pectans Mugard(2) although it is rather near it. O. mucosa is a very small Ophryoglene. The theront has one thick elliptical macronucleus, one small micronucleus; the buccal orifice is not kidney-shaped, but quite pointed in front; there is no tragus; the somatic infraciliature is not close; the peniculus P1 is characteristic. The tomont is ellipsoidal and surrounded by a thick mucous gangue. The tomites are not close together. O. mucosa is very different from O. gelifera and O. pectans Mugard(2). O. multimicronucleata. Near to O. polymicrocaryon Mugard(2), this Ophryoglene differs from it by the small size of all its vegetative elements and especially by its nuclear-apparatus. The latter includes numerous (5 to 6) bulky spherical micronuclei and one macronucleus looking like blackpudding which can be compared to that of O. singularis Canella and Trinchas(1). The theront is spindle-shaped and of a dark-grey colour. The spherical tomont secretes a mucous gangue which is not very thick. Besides, the somatic infraciliature and buccal in fraciliature of the theront (peniculus P1 especially) make O. multi micronucleata quite distinct from O. polymicrocaryon Mugard(2). 相似文献
12.
Philip Smith 《Feddes Repertorium》1968,77(1):61-64
Immunoelectrophoretic studies of the seed proteins of material provisionally referred to B. secalinus var. or f. hirsutus have revealed that it is serologically distinct from B. secalinus. The plant has many of the characters of B. secalinus fitting that species to life as a contaminant of cereal fields, but the floret and seed sizes are much smaller, and the sheaths are normally hairy. In Britain the plant appears to contaminate small-seeded pasture grasses which are sown on roadsides. The chromosome number of this plant is 2n = 14, unlike typical B. secalinus which has 2n = 28. The plant seems to be introduced in Britain, but its native distribution is not known. In view of its distinctive morphology and its serological difference from B. secalinus and other bromes, it is proposed to name it as a new species: Bromus pseudosecalinus P. SMITH sp. nov. 相似文献
13.
《Journal of bryology》2013,35(3):422-426
Abstract1. In six species of hepatics belonging to the Marchantiales and Acrogynae the large heteropycnotic chromosome found in addition to the sex chromosome or microchromosome is the nucleolar chromosome.2. The sex chromosomes and microchromosomes in these species, and in four of the five species of which the nucleolar chromosomes have been described by other authors, are not nucleolar chromosomes. Riccardia pinguis (L.) Gray appears to stand alone in having a nucleolar orpnizer on the sex chromosome in addition to that on an autosome bearing a heteropycnotic trabant.3. The large heteropycnotic sex chromosomes of certain species of Frullania belonging to the subgenus Galeiloba Steph. are not apparently homologous with the large heteropycnotic chromosome of Frullania africana Steph., belonging to the subgenus Chonanthelia Spr. This is not in accordance with the suggestion of Tatuno (1941) that all ' H-chromosomes' are phylogenetically homologous.4. It is argued that the nucleolar chromosomes throughout the hepatics, with the exception of the sex chromosome of Riccardia pinguis, may be phylogenetically homologous. 相似文献
14.
C. G. van Ginkel H. G. J. Welten J. A. M. de Bont 《Applied microbiology and biotechnology》1986,24(4):334-337
Summary Newly isolated Xanthobacter spp. were able to grow on the gaseous alkenes like ethene, propene, 1-butene and 1,3-butadiene. Resting-cell suspensions of propene-, 1-butene- or 1,3-butadiene-grown Xanthobacter Py10 accumulated 1,2-epoxyethane from ethene. Ethene-grown Xanthobacter Py10 did not produce any 1,2-epoxyalkane from the alkenes tested. Furthermore, propenegrown Xanthobacter Py2 accumulated 2,3-epoxybutane from trans-butene and cis-butene but did not form epoxides from other substrates tested. 相似文献
15.
Ultraviolet-sensitive mutants of Neurospora. I. Genetic basis and effect on recombination 总被引:13,自引:0,他引:13
Alice Louise Schroeder 《Molecular & general genetics : MGG》1970,107(4):291-304
Summary Three new UV-sensitive mutants were obtained using replica plating of the colonial crisp ragged strain of Neurospora crassa — uvs-3 (near cys-10, linkage group IVL), uvs-4 (4 units left of ad-4 IIIR) and uvs-5 (<1 unit from vel, IIIR). These are genetically distinct from uvs-1 (Chang and Tuveson, 1967) and uvs-2 (IVR, Stadler and Smith, 1968). They are two to three times more sensitive to UV than wild type. Heterokaryons between any two mutations are not sensitive, showing that all three are recessive. In heterozygous condition, none of the mutants affects crossing over. In homozygous condition, uvs-4 does not affect gene conversion as measured by prototroph frequency in crosses of pan-2 (B2) x pan-2 (B36), nor does it affect crossing over between cot-1 and tryp-4. Neither uvs-3 nor uvs-5 is fertile in homozygous crosses; asci do not develop beyond the multinucleate ascogenous hypha stage. — Mitotic effects were studied using strains haploid for UV-sensitivity but duplicated and heterozygous for mating type. In(ILR) H 4250 and Tp(III) 39311 were used to generate such duplications. Release from a slow-growing phenotype occurs when a mitotic event makes mating type homo-or hemizygous. With uvs-3, but not uvs-4 or uvs-5, release occurs 2 days earlier than in controls. Thus uvs-3 may affect chromosome breakage or mitotic recombination. The number of chromosome rearrangements present in a sample of colonies grown from single conidia of uvs-3 stocks is the same as in controls, but in test crosses 13% of the colonies produced barren perithecia of a type that is characteristic of duplications.A portion of a dissertation submitted to the Graduate Division of Stanford University in partial fulfillment of the requirements for the degree of Doctor of Philosophy.This work was supported by a National Science Foundation predoctoral fellowship and Public Health Service Research grant AI-01462. 相似文献
16.
Self-incompatibility in Brassica campestris c.v. Arlo is controlled by a single locus sporophytic system. The identity and expression of the S alleles were determined in eight inbred and two hybrid families. It was found that co-dominance of alleles is more frequent in the stigma, whereas dominance relations between pairs of alleles predominate in the pollen. A linear order of dominance was established between six S alleles and alleles high, intermediate and low in the dominance series were recognized.In considering the variation in the expression of compatibility and the segregation ratios in inbred, F1, F2 and backcross progenies, the presence of a specific S allele conditioning self-fertility, or a single dominant self-compatibility factor independent of the S locus could not be established. Instead, self-compatibility in this cultivar was ascribed to the segregation of a polygenic complex which is capable of modifying the incompatibility reaction to the point of self-fertility, or to a reduction in the strength of the reaction due to the presence of S alleles low in the dominance series. 相似文献
17.
Abdel Monem El Mofty M.D. Charles D. Jeffries Ph. D. H. Medhat El Komy M. D. 《Mycopathologia》1968,34(1):61-64
Summary 121 cases diagnosed clinically as tinea capitis were examined microscopically and culturally. In 80 cases the causative organism could be cultured.T. violaceum was the causative organism of the majority of the cases as it caused 47.5 % of the cases,T. schoenleinii 31.3 %,M. canis caused 26.1 %,T. tonsurans 1.3 %, whileM. audouinii caused none. In most of the cases ofT. violaceum infection, scaling and mild inflammation were the common clinical manifestation. The black dot or the bald patch appearance was rarely seen. Favus did not necessarily show the characteristic scutulae; in many cases ofT. schoenleinii infection, only few scales and mild inflammation were present. 相似文献
18.
Unlike many higher plants Euphorbia granulata and E. heterophylla do not encourage the development of fungi in their rhizospheres. Fungi recovered therefrom were limited both in number and range of species. The rhizosphere of E. heterophylla was slightly favourable to soil fungi when compared with the other weed plant. Aspergillus niger was least affected by both types of rhizosphere. Expressed latexcontaining sap of E. granulata was remarkably inhibitory to submerged cultures of A. flavus, A. nidulans, Fusarium sp., Curvularia sp. and Helminthosporium. Conidia and mycelial fragments recovered from these cultures failed either to germinate or resume growth thus exhibiting an antifungal property of E. granulata latex. 相似文献
19.
《Journal of bryology》2013,35(2):99-104
AbstractThe relationships among western Eurasian and Macaronesian Cratoneuron filicinum (Hedw.) Spruce var. filicinum, C. filicinum var. atrovirens (Brid.) Ochyra, and C. curvicaule (Jur.) G.Roth were explored by ITS and the chloroplast markers rpl16 and tRNA-Gly. Haplotype networks, Jacknife, and Neighbour joining trees all provide high support for the recognition of C. curvicaule as distinct from C. filicinum, whereas the two varieties of the latter could not be distinguished. It is concluded that C. filicinum var. atrovirens most likely represents a phenotypic modification of C. filicinum that occurs especially in certain submerged environments or under heavily dripping water. The maximal support for the Cratoneuron clade and the small and quantitative morphological differences between its two species are arguments for not splitting this genus. 相似文献
20.
Francis R. Trainor 《Journal of phycology》1966,2(2):85-89
Four strains of Scenedesmus parisiensis Chodat were studied in xenic and axenic culture in 3 media as well as in cultures incubated in sterile vessels in nature. Organized coenobia are usually produced but these may have merely short spines, spines and serrate edges, or lack wall ornamentation. Because the serrate edge is either not formed or cannot be readily detected in most cases, it is not a satisfactory morphological feature for delimiting this species. In laboratory studies it is noted that S. parisiensis might be confused with S. denticulatus rather than S. brasilien-sis. Inasmuch as both xenic and axenic cultures of the -f strains produced similar results, S. parisiensis can be readily characterized. 相似文献