共查询到20条相似文献,搜索用时 22 毫秒
1.
Summary Two aerobic mesophilic species of a new genus belonging to the familyActinoplanaceae are described under the nameDactylosporangium (D. aurantiacum strainD/748 type species andD. thailandensis strainD/449). The new genus is characterized by the production of finger shaped sporangia emerging directly from the vegetative mycelium.The motile sporangiospores, three to four in number are arranged in a single straight row inside the sporangium.The genusActinoplanes of the familyActinoplanaceae was described in 1950 byCouch and is characterized by the bacteria-like, flagellated spores formed in sporangia. Other members of the familyActinoplanaceae have been studied byKarling (1954),Rothwell (1957) andCross
et al. (1963) in the United States, byGaertner (1955) in Germany, byVan Brummelen andWent (1957) in Holland, byNonomura andOhara (1960) in Japan, byTaig
et al. (1962),Tsyganov
et al. (1963), andKoniev
et al. (1965) in Russia. Except for the organisms studied byKarling and byRothwell, which undoubtedly belonged to theActinoplanes but were not studied in pure culture, the organisms studied by most of the other authors belonged to the genusStreptosporangium.Three new genera having motile spores were described more recently:Ampullariella andSpirillospora described byCouch (1963, 1964), andPlanomonospora byThiemann
et al. (1967b). 相似文献
2.
The regulation of homoserine dehydrogenase activity was studied in nineAzotobacter strains belonging to five different species. In all the species the enzyme is subject to feedback inhibition byl-threonine andl-isoleucine, the first being much more active as inhibitor. The inhibition byl-threonine is noncompetitive with respect to NADPH and of mixed type with respect to aspartate-Β-semialdehyde; the inhibition
byl-isoleucine is noncompetitive with respect to both substrates. The synthesis of homoserine dehydrogenase inAzotobacter chroococcum I.P. is somewhat repressed by 1mm l-methionine and 5mm l-isoleucine. In all the strains examined either NADPH or NADH can serve as cofactors for this activity, though the ratio of
activity with the two pyridine nucleotides (NADPH/NADH) shows higher values (3.3–3.8) in the speciesmacrocytogenes andinsignis than in thechroococcum, beijerinckii andvinelandii group (1.5–1.6). The pattern of control of this enzyme in the genusAzotobacter is discussed in relation to other bacterial homoserine dehydrogenases.
We are grateful to Dr. G. N. Cohen, Service de Physiologie Microbienne, Institut Pasteur, Paris, for helpful discussions and
encouragements. 相似文献
3.
The oxidation of 17 carbon compounds by 13 strains ofMicrococcus luteus was studied. It was shown that all strains oxidized Na-acetate, Na-lactate, glycerol, glucose, galactose, sucrose, maltose and fructose. The oxidation of mannitol, sorbitol, xylose, ribose, rhamnose, starch, lactose and arabinose was variable. Dulcitol was not oxidized at all. We have shown that the species, considered byKocur andMartinec (1962) to be identical withM. luteus, possess the same oxidation pattern. 相似文献
4.
Summary Electron-micrographs ofGluconobacter melanogenus strain AC 8 (formerlyG. liquefaciens), andG. melanogenus strain U 4, have conclusively confirmed the findings ofShimwell andCarr (1959),Stouthamer (1960), andLeifson (private communication), that these strains are not polarly flagellatedAcetomonas orGluconobacter strains, but peritrichously flagellated acetate-oxidisingAcetobacter ones.
When transferred to the latter genus all evidence that these two genera are derived from a “common pool of ancestors”, as
claimed byDe Ley (1961), disappears. 相似文献
5.
Summary Cell-free extracts of gram-negative, non-fermentative, marine eubacteria were assayed for aspartokinase activity. The organisms
tested included polarly flagellated species and groups which had GC contents in their DNAs of 46 to 64 moles % (Alteromonas, Pseudomonas) as well as species which had peritrichous flagellation and moles % GC contents of 53 to 68 (Alcaligenes). The results of these studies suggested that in all the strains tested, aspartokinase activity was catalyzed by a single
enzyme. On the basis of the effect ofl-threonine,l-lysine,l-methionine, andl-isoleucine on activity, five different types of aspartokinases (designated I through V) were delineated. In aspartokinase
types I through IV,l-threonine andl-lysine inhibited activity by means of a concerted feedback inhibition; in type V, activity was inhibited byl-threonine but unaffected byl-lysine. In types I, III, and IV,l-threonine andl-lysine alone were inhibitory, while in type II these effectors had virtually no effect on activity when tested singly. Three
distinct responses were observed in the presence of two other end products of the aspartate pathway,l-methionine andl-isoleucine. In types I and II, these two amino acids usually stimulated activity and overcame the inhibition byl-threonine andl-lysine; in types IV and V,l-methionine andl-isoleucine had no effect; and in type III these amino acids inhibited activity. The results of this study indicate that the
aspartokinases of a number of species and groups of marine bacteria have similarities and differences which should be of use
in making future taxonomic groupings. 相似文献
6.
Summary
E. coli KB (Benzer) differs from other common laboratory strains in possessing a glycyl sRNA synthetase with a 50 to 100 times elevated K
m
for glycine. The degree of charging of glycyl sRNA in this strain can be increased by supplementing the growth medium with glycine. The altered enzyme has been used as a marker by which to map its structural gene. Linkage analysis of recombinants from uninterrupted matings, and cotransduction (80%) of the synthetase withxyl, indicate that this gene is located betweenxyl andmalt, close toxyl, at min 69.5 on the map drawn byTaylor andThoman (1964). 相似文献
7.
Some morphological and cytological aspects ofEpidermophyton andMicrosporon were studied according to the classification of the Fungi Imperfecti suggested byHughes.It was found that origin of macroconidia in the genusEpidermophyton is quite different from that of the genusMicrosporon. The macroconidia of the speciesMicrosporon gypseum, M. fulvum andM. canis presented only pseudosepta; true septa were present inM. cookei, M. audouinii andM. vanbreuseghemii. On the basis of the morphological features of macroconidia a simple analytical key for the species ofMicrosporon most frequently isolated in Italy is proposed.These studies were supported by grant of the Consiglio Nazionale delle Ricerche of Italy under contract n.69.01074/115.2798. 相似文献
8.
Hammett Frederick 《Protoplasma》1933,20(1):161-168
Summary and Conclusion Mitotic activity is enhanced by sulfhydryl and held back by its sub-oxidized derivative in all the three chief germ layer
derivatives of regeneratingClymenella torquata.
Thus, here as elsewhere, growth by increase in cell number is found to be regulated by the naturally occurring essential chemical
equilibrium comprised of these chemical groups.
The degree of enhancement of mitotic activity by sulfhydryl differed in the three types of growing tissue. This experimental
demonstration of the existence of an inherent difference in mitotic potentiality allows the inference to be drawn that relative
proliferation intensity has played an important r?le in evolution.
The mesodermal derivative exhibited the greatest mitotic potentiality. In this property lies, in significant part, an explanation
for the greater diversity of differentiated mesodermal end-products.
The experiments here reported were done byDorothy Wall Hammett andGeorgia Brawner. The sections were made byNevart Chatalbash. The unstinted assistance of these workers is truly appreciated as is the everlasting support of DoctorStanley P. Reimann, without which this work could not have been accomplished. 相似文献
9.
G. M. Weir 《Mycopathologia》1962,18(3):184-188
Summary The respiration, as measured by oxygen uptake, was higher for healthy tissue adjacent to soft rots of apple (var. Bramley) caused byPenicillium expansum
Link andThom. andBotrytis cinerea
Fr. and of potato tuber (var. Arran Banner) caused byErwinia aroideae
Townsend, than tissue at a more distant site. The respiration of tissue adjacent to a physiological rot caused by bruising was not affected. It was concluded that there is diffusion of a substance(s) from the site of infection which causes an increase in the rate of respiration of the adjacent tissue.This work formed part of a Ph. D. thesis submitted to the University of London, July 1961. 相似文献
10.
V. Labeyrie 《BioControl》1961,6(4):257-263
Summary The layings ofCassida deflorata
Suffr. are parasited in southern France byMymaridae (Anaphoidea sp. andFulmekiella ovata
soyka),Trichogrammatidae (Monorthochaeta nigra
Blood.) andEulophidae (Foersterella flavipes
Foerst. andTetrastichus rhosaces
Walk.).
In the Alpes-Maritimes, two successive generations ofMymaridae andTrichogrammatidae seem to attack the layings ofC. deflorata.
In Corsica, parasitism byMymaridae andF. flavipes is very frequent and may be the essential regulating factor of the populations ofCassida.
In the other regions that have been studied, although the large number ofCassida imagos appearing in spring show that mortality during the aestivation and hibernation is not the primary factor, it does
not seem that the limitation of the populations is essentially caused by the activity of oophagous insects.
相似文献
11.
Indira Kalyanasundaram 《Antonie van Leeuwenhoek》1973,39(1):521-528
Three strains ofMadurella mycetomi, two ofM. grisea, and two ofRhinocladiella 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 suitedM. mycetomi about as well as 30C.R. mansonii grew less well at 37C than at 30C, andM. grisea did not grow at the higher temperature.
M. grisea andR. mansonii further differed fromM. 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
byM. mycetomi; the other species did not use it.
A possible relationship ofM. grisea andR. mansonii is discussed. 相似文献
12.
Summary The namePseudoeurotium globosum
Rai andTewari n. sp. has been given to a fungus isolated from soil collected from the banks of a stream in village Harchandpur, District Rae Bareli, (U.P.) India. This form is distinguished from any other described so far in this genus, in having multisporous asci with large globose ascospores. P.globosum n. sp. inhabits a specialised habitat, and this along with the fact that it was isolated only byWarcup's Soil-plate Method, makes it an ecologically interesting form. 相似文献
13.
Nils Aall Barricelli 《Molecular & general genetics : MGG》1966,98(3):287-298
Summary Several hypotheses concerning the fate of the parental DNA of phage T4 are discussed as possible interpretations of experimental data presently available. Particularly the experimental implications of the breakage-rejoining hypothesis, and the possibility that the joints between parental and progeny DNA may or may not be reversible during intracellular growth, are taken into consideration. Some of the crucial experiments, byLevinthal, byKahn, byStent, Sato andJerne, byKozinski andKozinski, and byTomizawa andAnraku, are briefly described. The results of these experiments make it possible to rule out most of the hypotheses considered. Only the following hypothesis is found to be consistent with present experimental data: A portion (roughly one half) of the parental DNA is transmitted to the progeny in the form of large segments (average size 40% or more of a single T4-DNA strand) which are reversibly joined to newly formed DNA and usually remain intact if transmitted again to later generations. Another protion of the parental DNA is transmitted in small segments which might be irreversibly joined to newly formed DNA. The joints between parental and progeny DNA are reversible during intracellular growth (Anraku andTom zawa, 1965).This work was supported by research grant GM-12581 from the Division of General Medical Sciences of the National Institutes of Health, United States Public Health Service. 相似文献
14.
V. P. Agnihotri 《Mycopathologia》1962,17(4):354-358
Summary The utilization of certain amino acids when supplied in three different combinations, (a) glycine, serine, valine, histidine (b) methionine, valine, alanine, arginine (c) leucine, tryptophane, glutamic acid, aspartic acid, byA. nidulans (Eidam)Wint;A. rugulosus
Thom andRaper;A. variecolor (Berk. andBr.)Thom andRaper;A. quadrilineatus
Thom andRaper andA. violaceus
Fennel andRaper was studied through circular partition chromatography. It was found that these Aspergilli which are so closely related morphologically exhibited different rate of assimilation of amino acids. Amino acids in mixtures were utilized better than when supplied singly. Although different species had their own preference to certain amino acids yet there was a simultaneous utilization of both good and poor amino acids. 相似文献
15.
Maria F. S. Barbosa Maria B. de Medeiros Ismael M. de Mancilha Henry Schneider Hung Lee Ph.D. 《Journal of industrial microbiology & biotechnology》1988,3(4):241-251
Summary The ability to convertd-xylose to xylitol was screened in 44 yeasts from five genera. All but two of the strains produced some xylitol with varying rates and yields. The best xylitol producers were localized largely in the speciesCandida guilliermondii andC. tropicalis. Factors affecting xylitol production by a selectedC. guilliermondii strain, FTI-20037, were investigated. The results showed that xylitol yield by this strain was affected by the nitrogen source. Yield was highest at 30–35°C, and could be increased with decreasing aeration rate. Using high cell density and a defined medium under aerobic conditions, xylitol yield byC. guilliermondii FTI-20037 from 104 g/ld-xylose was found to be 77.2 g/l. This represented a yield of 81% of the theoretical value, which was computed to be 0.9 mol xylitol per mold-xylose.Issued as NRCC publication No. 28798. 相似文献
16.
Summary A mutual antagonism (in vitro) has been shown betweenTrichophyton rubrum andCandida albicans by means of two membered pure cultures and by means of cultures filtrates from each organism grown singly. The growth ofT. rubrum was inhibited by metabolic products ofC. albicans. The pigment ofT. rubrum has been shown to be a pH indicator in vivo. Metabolic products ofT. rubrum completely inhibit the development of mycelia byC. albicans, but have little effect on growth in the yeast phase. Chemical fractionation experiments indicated that there are two diffusible metabolic products ofT. rubrum affecting mycelia development: 1) soluble in water and in acetone, heat stable, and adsorbed by activated charcoal, 2) soluble in water, insoluble in acetone, heat labile, and not adsorbed by activated charcoal. The general phenomenon of yeast to mycelia conversions has been considered in detail. A notation system has been developed in this connection; yeast (Y) to mycelia (M) transformations may be expressed as YM; interconversions of the type exhibited byBlastomyces may be written Y:M. The relationships between these processes and the analogous bacteria (B) to filament (F) conversions, B F, has been pointed out. Evidence that Y..M, YM, and BF may result from the inhibition of a common unit enzymatic mechanism has been presented. Converging evidence from such diverse fields as the physicochemical study of the kinetics of bacterial growth (Hinshelwood), genetics of irradiated bacteria (Witkin; Eisenstark andClark), cytochemical mechanism of penicillin action (Pratt andDufrenoy), and dimorphism of pathogenic fungi (this paper;Nickerson andEdwards) are all interpreted as pointing in this direction. 相似文献
17.
J. Lodder 《Antonie van Leeuwenhoek》1947,12(1-4):273-280
III Conclusion and Summary
Zygosaccharomyces Marxianus andSaccharomyces macedoniensis belong to the same species. This species is met with in the haplophase (Z. Marxianus) as well as in the diplophase (S. macedoniensis). It was possible to bring this yeast from the haplophase into the diplophase and vice versa. By keeping this yeast during long times on maltagar it showed a tendency to change from the haplophase into the diplophase, but not into the opposite direction.It seems quite possible thatHansen, who did not describe a conjugation in this yeast, had met with the diplophase.It has been once more emphasized — at whichWinge andLaustsen and alsoLindegren andLindegren have pointed —, that the genusZygosaccharomyces is no valid genus.The yeast studied here belongs to the genusSaccharomyces and must be designated with the original name given to it byHansen:Saccharomyces Marxianus.For the sake of completeness it is mentioned here that also an imperfect stage ofS. Marxianus has been describedviz., Candida macedoniensis (A. Castellani) Berkhout (I).Saccharomyces fragrans Beijerinck has to be considered as its synonym. 相似文献
18.
Food selection by Labeo Rohita (Ham.) and its feeding relationship with other major carps 总被引:1,自引:1,他引:0
Selectivity of food byLabeo rohita (Ham.) was studied in a stocking pond (Moat), by calculating an Electivity index (E) for each food organism as described byIvlev (1961). It was found thatL. rohita was definitely selective in its feeding. In case of fingerlings, there was a strong selection for zooplanktonic organisms (Arcella andDifflugia among protozoans,Keratella andBrachionus among rotifer andDaphnia andCyclops among crustaceans) and smaller algae (Cosmarium andClosterium among desmisd,Euglena andVolvox among phytoflagellates and algal spores and zygotes) while most of the phytoplanktonic organisms, belonging to green algae, diatoms and blue green algae, were avoided. In case of adults, a strong negative selection was observed for all zooplanktonic organisms and a strong positive selection for most of the green algae and diatoms (Ankistrodesmus, Zygnema, Spirogyra, Selenastrum, Pediastrum, Scenedesmus, Tetraspora, Stephanodiscus, Naviculla, Diatoma, Synedra andNitzchia). However, all blue green algae were avoided.The feeding relationship ofL. rohita with other major carps,Cirrhina mrigala (Ham.) andCatla catla (Ham.) was studied in two different habitats, pond and river. It was observed that in both habitats all three species were found to feed on almost similar types of food organisms, but the quantity of any food item eaten by adults differed markedly from one species to another and the food items which were dominant in one species, were of secondary importancce for the other two species. The adults ofL. rohita were found to feed mainly on phytoplankton and macrovegetation, the main food of adultC. mrigala was decayed organic matter, sand and mud supplimented by plankton, while the food of adultC. catla was chiefly composed of zooplankton, and some phytoplankton. Hence there was no true identity of feeding habits between the adults of any two species. However, there was an indication of competition for food between the fingerlings of all three species, because all of them feed mainly on zooplankton (Crustaceans, rotifers and protozoans). However, such feeding habits lasted a very short time only and as the fishes grew, their feeding habits diverged. 相似文献
19.
J. Netrval 《Folia microbiologica》1977,22(2):106-116
The effect of 18 amino acids and 7 organic acids on the production ofl-asparaginase EC-2 by a strain ofEscherichia coli in a chemically defined medium was investigated under moderate aeration. All the amino acids and some of the organic acids
stimulated the enzyme production. The specific activity without stimulants was about 0.16 nkat per mg dry weight, with stimulants
it lay between 1 and 6 nkat per mg dry weight but withl-leucine andl-methionine the values were 12 nkat and 17 nkat per mg, respectively. When two organic or amino acids were added simultaneously
at concentrations that were suboptimal for stimulation, the stimulating effects were cumulative in most cases. When cells
were grown under conditions approaching anaerobiosis, the specific activity reached, even in the absence of stimulants, values
as high as 5 nkat per mg; under these conditions, a further substantial increase in specific activity was only caused byl-leucine andl-methionine. Stimulating effects ofdl-lactate and of some amino acids were also found in other strains ofEscherichia coli. The ability to grow on a medium withl-asparagine as the sole source of both nitrogen and carbon was found in two strains; growth took place even when there was
no measurable activity ofl-asparaginase EC-2. 相似文献
20.
Thiosulfate was oxidized stoichiometrically to tetrathionate during growth on glucose byKlebsiella aerogenes, Bacillus globigii, B. megaterium, Pseudomonas putida, two strains each ofP. fluorescens andP. aeruginosa, and anAeromonas sp. A gram-negative, rod-shaped soil isolate, Pseudomonad Hw, converted thiosulfate to tetrathionate during growth on acetate. None of the organisms could use thiosulfate as sole energy source. The quantitative recovery of all the thiosulfate supplied to heterotrophic cultures either as tetrathionate alone or as tetrathionate and unused thiosulfate demonstrated that no oxidation to sulfate occurred with any of the strains tested. Two strains ofEscherichia coli did not oxidize thiosulfate. Thiosulfate oxidation in batch culture occurred at different stages of the growth cycle for different organisms:P. putida oxidized thiosulfate during lag and early exponential phase,K. aerogenes oxidized thiosulfate at all stages of growth, andB. megaterium andAeromonas oxidized thiosulfate during late exponential phase. The relative rates of oxidation byP. putida andK. aerogenes were apparently determined by different concentrations of thiosulfate oxidizing enzyme. Thiosulfate oxidation byP. aeruginosa grown in chemostat culture was inducible, since organisms pregrown on thiosulfate-containing media oxidized thiosulfate, but those pregrown on glucose only could not oxidize thiosulfate. Steady state growth yield ofP. aeruginosa in glucose-limited chemostat culture increased about 23% in the presence of 5–22 mM thiosulfate, with complete or partial concomitant oxidation to tetrathionate. The reasons for this stimulation are unclear. The results suggest that heterotrophic oxidation of thiosulfate to tetrathionate is widespread across several genera and may even stimulate bacterial growth in some organisms. 相似文献