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61.
The mymarid Anaphes n.sp. was observed to parasitize the eggs of the carrot weevil Listronotus oregonensis (LeConte) up to 138 h old at 23±1°C and 18L:6D. Adult emergence of the parasitoid was observed in 85%‐97.5% of the weevil eggs 42–138 h old and host embryogenesis was interrupted in nearly 100% of these eggs. In host eggs of 18 h old, parasitism was very high but not all parasitoids completed their development and their subsequent emergence was generally retarded. An.sp. could parasitize host eggs 162 h old, but such an attack rarely retarded the normal development of the host. The parasitoid was unable to complete its development in sterile carrot weevil eggs. 相似文献
62.
Three strains of strictly anaerobic Gram-negative, non-sporeforming, motile bacteria were enriched and isolated from freshwater sediments with 1,3-propanediol as sole energy and carbon source. Strain OttPdl was a sulfate-reducing bacterium which grew also with lactate, ethanol, propanol, butanol, 1,4-butanediol, formate or hydrogen plus CO2, the latter only in the presence of acetate. In the absence of sulfate, most of these substrates were fermented to the respective fatty acids in syntrophic cooperation with Methanospirillum hungatei. Sulfur, thiosulfate, or sulfite were reduced, nitrate not. The other two isolates degraded propanediol only in coculture with Methanospirillum hungatei. Strain OttGlycl grew in pure culture with acetoin and with glycerol in the presence of acetate. Strain WoAcl grew in pure culture only with acetoin. Both strains did not grow with other substrates, and did not reduce nitrate, sulfate, sulfur, thiosulfate or sulfite. The isolates were affiliated with the genera Desulfovibrio and Pelobacter. The pathways of propanediol degradation and the ecological importance of this process are discussed. 相似文献
63.
Growth of alfalfa (Medicago sativa cv. Vernal) seedlings was compared after inoculation with combinations of either Pratylenchus penetrans and Fusarium soloni or P. penetrans and F. oxysporum f. sp. medicaginis. A synergistic disease interaction occurred in alfalfa when F. oxysporum and P. penetrans were added simultaneously to the soil. Alfalfa growth was suppressed at all inoculum levels of P. penetrans and F. oxysporum, but not with F. solani. Seedlings inoculated with the nematode alone gave lower yields than when inoculated with either Fusarium species alone. Fusarium oxysporum, but not F. solani, was pathogenic to alfalfa under similar experimental conditions. Fusarium oxysporum did not alter the populations of P. penetrans in alfalfa roots, whereas the presence of F. solani was associated with a diminished number of P. penetrans in the roots. 相似文献
64.
W. Reisser 《Protoplasma》1981,105(3-4):273-284
Summary The greenStentor polymorphus harbours unicellular coccoid chlorophycean algae. They are located in food vacuoles, where they show various states of digestion, as well as in individual so-called perialgal vacuoles. According to their characteristic morphological properties the algae belong to the genusChlorella. They can be isolated from the ciliate and cultivated in mass cultures in a sterile defined inorganic medium supplemented with vitamins B1 and B12. The algae have no secondary carotenoids and excrete maltose by a pH-dependent mechanism. They thus show a conspicuous physiological similarity to the symbiotic chlorellae ofParamecium bursaria andHydra viridis, which also excrete maltose.A comparison of the properties of the chlorellae isolated fromStentor polymorphus and of the intactStentor polymorphus-Chlorella unit with the characteristic features of symbiotic chlorellae and with endosymbiotic systems containingChlorella sp. in general, lead to the conclusion that the greenStentor polymorphus is also a true endosymbiotic system. 相似文献
65.
DOUGLAS A. EAGLES ROBERT A. GREGG DONALD M. SPOON 《The Journal of eukaryotic microbiology》1980,27(4):426-431
SYNOPSIS. The surface membrane potentials of suctorian genus Heliophrya were studied with intracellular electrodes. Resting membrane potentials averaged -32 mV, and spontaneous depolarizing potentials occurring at apparently random intervals and having a variety of waveforms were routinely observed. Such spontaneous potentials were correlated in time with visually monitored contractile vacuole activity. Individual contractile vacuoles had unique, although somewhat variable, electrical signatures. In the presence of an intracellular electrode all vacuoles contracted independently, but at approximately the same frequency. The amplitude of the electrical potentials increased when the membrane was hyperpolarized and decreased when it was depolarized. The sign of such potentials reversed at between -10 mV and the zero membrane potential. A 20% decrease in the membrane resistance was measured at the peak of the spontaneous depolarizing potentials. 相似文献
66.
Patrick De Wever 《Geobios》1981,14(1):5-15
Studies of skeleton elements of several jurassic species of Saitoum allow to compare them with Poulpus from Trias. The sub-family Poulpinae is introduced, caracterised by three cephalic arcs and the collar position of the cephalic structure. Among the jurassic forms, 4 species are newly described: S. corniculum, S. elegans, S. levium and S. trichylum. 相似文献
67.
On a new charophyte from India 总被引:1,自引:1,他引:0
Chara indica is described as a new species on morphological and cytological grounds.Part of Ph. D. Thesis of Ranchi University. 相似文献
68.
The genusGeitleria (Cyanophyceae orCyanobacteria): Distribution ofG. calcarea andG. floridana n. sp.
E. Imre Friedmann 《Plant Systematics and Evolution》1979,131(3-4):169-178
The calcifying cave inhabitant atmophytic blue-green algaGeitleria calcarea is reported from new localities in Florida and in the Cook Islands.—G. floridana n. sp., is described from caves in Florida. The calcified sheath has the shape of a quadratic prism and is built of crystalline acicular subunits about 0.1 µm in diameter. The subunits mostly form a rhombic lattice pattern but in some cases, they are not distinguishable and then the surface of the sheath is smooth.This paper is dedicated with gratitude to my former teacher, Prof. Dr.Lothar Geitler, for his 80th birthday. 相似文献
69.
Colchicine has a temperature-dependent cytotoxic effect on Entamoeba sp. (Laredo isolate) that is most apparent when the drug is applied during the initiation of cultures at a concentration of 7.5 mM or higher. Continued transfer of cultures in medium containing progressively increasing concentrations of colchicine has resulted in a variant that grows prolifically in the presence of colchicine (7.5 mM) with a generation time comparable to that of the parent stock. Comparison of a number of parameters of the 2 variants revealed that colchicine resistance was accompanied by a change in cell shape, a reduced membrane permeability, which could partially be overcome by the addition of dimethyl sulfoxide (DMSO), and a reduced tolerance to osmotic stress. However, the parent strain and resistant variant were equally susceptible to cycloheximide and puromycin suggesting that the acquired colchicine resistance may not be explained on the basis of an entirely unspecific generalized reduced ability for drug uptake. Colchicine resistance and altered structure were found to be stable over a long period of time. The possible interdependence of these 2 parameters and their relation to cell motility in Entamoeba sp. are discussed. 相似文献
70.
Donald A. Bryant Alexander N. Glazer Frederick A. Eiserling 《Archives of microbiology》1976,110(1):61-75
Studies are presented of the biliproteins of Anabaena sp. This filamentous cyanobacterium contains three major biliproteins. Whereas two of these, C-phycocyanin and allophycocyanin, are common to all cyanobacteria, the third, phycoerythrocyanin (max568nm) has hitherto not been described and its distribution among cyanobacteria appears to be limited.
Anabaena variabilis and Anabaena sp. 6411 allophycocyanin, C-phycocyanin, and phycoerythrocyanin were purified to homogeneity and characterized with respect to molecular weight, isoelectric point, absorption spectrum and amino acid composition. The and subunits of each of these proteins were also purified to homogeneity and characterized in the same manner. The tetrapyrrole chromophore content was determined for each of the proteins and subunits. The subunit of phycoerythrocyanin carries a novel phycobiliviolin-like chromophore. This chromophore has not previously been detected in cyanobacterial biliproteins, but has been noted as a prosthetic group of a cryptophytan phycocyanin.Sedimentation equilibrium studies show that at pH 7.0, at protein concentrations of 0.2–0.6 mg/ml, allophycocyanin, C-phycocyanin and phycoerythrocyanin, each exists as a trimeric aggregate, ()3, of molecular weight of approximately 105000. Structural studies of microcrystals of these three biliproteins by electron microscopy and X-ray diffraction reveal a common plan for the construction of higher assembly forms. The major building block appears to be the trimer ()3. It is proposed that this is a dise-like structure about 3.0×12.0 nm. The individual or subunits are roughly spherical, 3 nm in diameter. Allophycocyanin trimers stack to form bundles of rods which form long needles. Both phycocyanin and phycoerythrocyanin form double dises ()6 which are visible as ring-shaped structures by electron microscopy. The mode of assembly of the biliproteinstructures in the phycobilisome is, as yet, unknown.Abbreviation Used SDS
sodium dodecyl sulfate
Dedicated to Prof. Dr. Roger Y. Stanier on the occasion of his 60th birthday. 相似文献