摘要:

SYNOPSIS.SterileDidinium nasutumwere fedParamecium Aureliawhich had been grown on monofloral cultures of five different species of bacteria and on a wild mixed culture of bacteria. Didinia grown on monoflorally‐fed paramenia or starved paramecia maintained a low daily division rate (0.88‐2.06), and after 3 or 4 days died, frequently showing structural abnormalities before death. Didinia fed paramecia grown on a wild mixture of bacteria showed a higher division rate (4.96), did not die after 3 or 4 days, and encysted, when the food was exhausted. It is suggested that a diet consisting of monoflorally‐fed or starved paramecia is inadequate forDidinium. This may be due to the lack of some substance or substances related to the enzyme system of the predator, possibly proteolytic enzymes elaborated by paramecia. In the experiments of Gause on the destruction of one species by another, his failure to establish population oscillations betweenDidiniumandParameciummight have been due to an inadequate diet for the didinia which resulted in their lack, of encystment and

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1960.tb00730.x

出版商:Blackwell Publishing Ltd    

年代:1960

数据来源: WILEY

摘要:

SYNOPSIS.The literature on the coccidia of the coypuMyo‐ castor coypusMol is reviewed. Four species ofEimeriahave been described in these animals:E. seideli, E. myopotami, E. pellucidaandE. coypi. The description ofE. coypiis similar toE. myopotamiin every respect, except for a little variationin size of the sporocyst It is therefore proposed to considerthis species synonymous withE. myopotami, Two new species ofEimeria, E. myocastorisp. now andE. nutriaesp. nov. are now described from the coypu, naturalised n England in Englan

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1960.tb00731.x

出版商:Blackwell Publishing Ltd    

年代:1960

数据来源: WILEY

摘要:

SYNOPSIS.Stomatogenesis inParamecium aureliais shown to involve the lower kineties of the right vestibular wall, the endoral membrane and perhaps the quadrulus. The anarchic field for the new buccal organelles is formed by granules produced from somatic kinetosomes of the right vestibular wall. The endoral membrane becomes incorporated into the buccal anlage and probably regulates orientation and development of the new organelles. A production of heretofore unobserved buccal kinetosomes from the quadrulus is described and it is suggested that these may form the new endoral membrane for the proter.During conjugation the infraciliature dedifferentiates in the area of fusion between the conjugants. The buccal organelles dedifferentiate at the time of pronucleus formation and transfer. It is suggested that dedifferentiation of structures in the fusion area is caused by a partial solation of the cortex in this area. The dedifferentiation of the buccal organelles results from the solation of the cytoplasm and the cortex of the paroral cone during pronucleus migration. The redifferentiation of the buccal organelles and somatic kinetosomes is suggested to be a recrystallization or gelation of the cortex with the structures re‐forming in their normal positions and not from an anarchic field as at fissio

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1960.tb00732.x

出版商:Blackwell Publishing Ltd    

年代:1960

数据来源: WILEY

摘要:

SYNOPSIS.Two new species ofEimeria, E. megaresiduaandE. longaspora, are described from the common American newt,Notopthalmus viridescens. The hosts were from the vicinity of Douglas Lake in Northern Michigan. Observations of timeof sporulation of the oocyst relative to host defecation and possible significance of the seasonal distribution of the parasites are discussed.

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1960.tb00733.x

出版商:Blackwell Publishing Ltd    

年代:1960

数据来源: WILEY

摘要:

SYNOPSIS.The exoerythrocytic forms ofPlasmodium gallinaceumin thin sections of infected tissue cultures have been examined with the electron microscope. It was seen that important changes occur in the fine structure of the parasite during the various phases of the cycle. The cytoplasm of the merozoites at the beginning and at the end of each cycle shows a great electron density due to a fine granulation. Larger granules are found at one pole of the parasite. The merozoites have a large nucleus in the center, and an oval body of great electron density at one pole, the significance of which is unknown. Short canaliculi can also be seen in the cytoplasm, but no mitochondria have been found.The cytoplasm of the schizonts shows a low electron density. It contains small particles scattered irregularly throughout its whole mass. The nuclei are not well defined; the oval body observed in the merozoites apparently has disappeared. Short canaliculi are present everywhere; however, mitochondria could not be identified with certainty.In the final phase of the cycle, in the rosette formations, the cytoplasm assumes again the fine granular structure. The future merozoites are grouped around a cytoplasmic core, with which they are directly connected. The whole segmenter is situated in a vacuole formation. In cross sections of the merozoites an opening in the central pole has been observed.

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1960.tb00734.x

出版商:Blackwell Publishing Ltd    

年代:1960

数据来源: WILEY

摘要:

SYNOPSIS.When exogenous ecdysone is injected into a host (adult or intermolt nymph) which has no ecdysone of its own, gametogenesis is induced in the protozoa of such a host, although the host itself never undergoes ecdysis. The time required to induce this sexual process varies in different genera and with the dosage of hormone administered; but it is never possible, regardless of the amount of hormone given, to induce gametogenesis in all the genera at the same time; some still begin a day or two later than others, but never 40‐45 days later as occurs in untreated roaches.Likewise, when exogenous ecdysone is administered to a nymphal host in the molting period, the sexual cycles of its protozoa are greatly accelerated, and the host undergoes ecdy‐sis much sooner than would otherwise have been the case. Both sexuality in the protozoa and the molting process in the host are accelerated. Only when large doses of ecdysone are administered are the sexual cycles of the protozoa modified in any way except a decided acceleration. Quite large amounts of ecdysone present special problems for the protozoa, problems they never encounter in nature. The growth and differentiation hormone ecdysone causes the protozoa to grow and differentiate so rapidly that many of them cannot keep pace; as a result, degeneration begins, and death follows. But this over‐acceleration effect of ecdysone and death of the protozoa occurs only in those genera which have not undergone gametogenesis when the large amount of hormone is administered; those which have completed gametogenesis are not affected at all. The results of acceleration have been observed in most genera, but have been studied more intensively inTricho‐nympha, where they are usually seen to be considerably more pronounced on the nuclei and chromosomes than on the cytoplasm. As a result, this genus, which invariably in nature undergoes only fertilization, is sometimes made to undergo either autogamy or endomitosis. The pronuclei, for example, differentiate and are ready to (and do) fuse before the cytoplasm of the gametocyte divides to form gametes. In the case of endomitosis, precocious differentiation of chromosomes seems to produce, or at least goes along with, premature degeneration of one centriole, the one that would ordinarily degenerate following fusion of gametes. Thus, nuclear division is made impossible.In some genera of the protozoa, the ecdysone titer must drop greatly before meiosis can begin. If the titer, after ecdysis. when it normally drops precipitously, is kept high with injections, meiosis does not begin; it is retarded for as long as the ecdysone titer is ke

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1960.tb00735.x

出版商:Blackwell Publishing Ltd    

年代:1960

数据来源: WILEY

摘要:

SYNOPSIS.The following types of transfauntions were made: from nymphs is an early stage of their molting period to nymphs 1‐50 days before ecdysis and vice versa; from recently molted nymphs to nymphs in all stages of the molting period and vicve versa. In such transfaunated half or more of the protozoa in a donor host were transferred to a recipient host. The recipient hosts wee defaunated with oxygen by subjecting them to 60 psi for 2 hours, twice the minimum time necessary to kill all their protozoa. Transfaunations were made 24 hours after defaunation.The sexual cycles, as a result of these transfaunation experiments, in addition to being prevented altogether in several genera, were modified principally in two ways: they were shortened to less than half the time required under natural conditions; they were lengthened, in some genera, from two days to over two months. Whether shorteing or lengthening occurs depends on the type of host used in the experiment. And the factor in the host that is responsible for the modifications is the ecdysone titer; transfaunation from a lower to higher to a lower titer, in general, serves to lengthen i

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1960.tb00736.x

出版商:Blackwell Publishing Ltd    

年代:1960

数据来源: WILEY

摘要:

SYNOPSIS.Plasmodium minasenseCarini and Rudolph is recorded from three of 28 examples ofGonyocephalus bor‐neensis(Schlegel) from Kepong and Bukit Lagong, Selangor, andP. vastator n. sp. is described from a single example ofDraco volansGray from Ulu Langat, Selangor. Both of these arboreal agamid lizards are new hosts for malaria parasites.P. vastatorn. sp. is characterized by its highly amoeboid trophozoites, nucleophilic schizonts producing from four to eight (usually six) merozoites, and large (up to 22.1 ± 8.1 μ) gametocytes which alter and ultimately destroy the host cell. Forty‐six other lizards of nine species, and 28 snakes of 11 species, proved negative forPlasm

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1960.tb00737.x

出版商:Blackwell Publishing Ltd    

年代:1960

数据来源: WILEY

摘要:

SYNOPSIS.An account of conjugation in an American species ofBlepharismais given. A comparison is also made with the available knowledge of the two Indian species of this genus. In the conjugating pair, the condensed macronucleus shows Feulgen negative regions. Before the conjugants separate, the macronuclear and micronuclear anlagen become distinguishable.The species is characterized by a number of striking features which become noticeable after syngamy. The synkaryon divides thrice giving rise to 8 bodies. Of these, 3 to 7 become the macronuclear anlagen and the rest, the micronuclei. The resorption of the old macronucleus occurs much later, just before the exconjugant attains the vegetative form. No metagamic fissions occur in this species and each exconjugant becomes a vegetative animal in 5 or 6 days. During this period, the macronuclear anlagen arrange themselves in a series and develop slender connections with one another to produce the moniliform macronucleus of the vegetative animal. The micronuclear anlagen, on the other hand, divide by mitosis to attain the vegetative number. In this species 40% to 45% of the exconjugants are viable and the rest die.

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1960.tb00738.x

出版商:Blackwell Publishing Ltd    

年代:1960

数据来源: WILEY

摘要:

SYNOPSIS.An accurate description ofCyclidium glaucomaO.F.M., 1786, is presented. Fixed specimens were treated with the Chatton‐Lwoff silver impregnation technique and the standard Feulgen nucleal reaction. Living material was examined by phase microscopy. Components of the infraciliature have been given special attention, particularly in the buccal area. In brief consideration of the systematic status of this species emphasis is placed upon the close relationship of the pleuronematine and tetrahymenine groups of hymenostome ciliates. Comparisons on structures found inC. glaucomawith corresponding structures in species belonging to quite closely related families are made, and the fundamental nature of the infraciliary tetrahymenal buccal apparatus and the polar basal granule‐complex is discus

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1960.tb00739.x

出版商:Blackwell Publishing Ltd    

年代:1960

数据来源: WILEY