摘要:

The incidence ofHepatozoon balfouri(Laveran, 1905) in examined populations of Egyptian jerboas was 41% inJaculus j. jaculus, 21% inJaculus o. orientalis, and nil inAllactaga tetradactyla. Infection in a few animals apparently less than 6 days old suggests the possibility of transplacental transmission. The cycle in erythrocytes and parenchyma cells of the liver is described; stages in liver are seldom seen in chronic infections. Blood of many other Egyptian rodents and insectivores was negative forH. balfouri.The sporogonic cycle in mites,Haemolaelaps aegyptiusKeegan, 1956, fed on infected jerboas, resembles that of other typicalHepatozoonspecies. Sporocysts contain 6 to 16 (usually 12) sporozoites. Infection rates in experimental cultures ofH. aegyptiusvaried greatly. Mites from only a single graphic area could be experimentally infected; in the same area, the infection rate inJ. jaculusis significantly higher than elsewhere. Biological races ofHaemolaelaps aegyptius, more or less refractive toH. balfouriinfection, may exist. Large numbers of mites, lice, fleas, and ticks removed from infected jerboas were uninfected, as were numerous arthropods experimentally fed on infected jerboas.Owing to the presence ofH. balfourifoci in widely differing ecological zones of North Africa and Sudan, different species of mites, and possibly of other arthropods, obviously transmit the infection; details of this likelihood require further investigation.

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1961.tb01209.x

出版商:Blackwell Publishing Ltd    

年代:1961

数据来源: WILEY

摘要:

A new astomatous holotrichous ciliate,Radiophryoides puytoraci, parasitic in the gut of the Indian freshwater oligochaete is described. This is the second finding of the astomatous ciliate parasite from the microdrili from Asia. Key to all the known and valid species ofRadiophryoidesis given.

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1961.tb01210.x

出版商:Blackwell Publishing Ltd    

年代:1961

数据来源: WILEY

摘要:

Specimens ofGlaucoma chattonilacking in oral areas and unable to divide were observed in both axenic and bacterized cultures. The frequency of incidence of astomy rose in the course of continued cultivation ofG. chattoniA, which was the strain most extensively studied.Observations on silver impregnated animals from mass cultures, and studies of individually isolated living ciliates, have both led to the conclusion that all cells destined to become astomous pass through a certain definite sequence of events. These axe: 1. Initial damage, not microscopically detectable, predisposes the cell in such a way that within a few generattons all of its progeny become astomous. 2. The ability to complete normal stomatogenesis is lost; the cell cannot maintain normal posterior oral anlagen and also cannot regenerate following damage to the existing oral area. At this stage the cell can still divide, so that astomous opisthes are produced. 3. The existing oral area disappears shortly after the ability to produce new oral areas is lost. Loss of ability to divide occurs simultaneously with loss of oral areas. 4. Finally, there is increasing disorganization of the kineties, gradually decreasing activity and death.The incidence of astomy was compared in several different strains ofG. chattoni, including two newly isolated from nature.

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1961.tb01211.x

出版商:Blackwell Publishing Ltd    

年代:1961

数据来源: WILEY

摘要:

Colpoda cucullusforms two kinds of resting cysts: stable cysts which withstand freezing and need 24 hours for activation, and unstable cysts which do not survive freezing, but are activated within 3‐4 hours. ImM 2,4‐dinitrophenol has no effect on stable cysts, and increases the respiration rate of unstable cysts by 100%. 1 mM methylene blue increases oxygen consumption in both stable and unstable cysts, by 200% and 400% resp. The results suggest that the inhibition of metabolism is more complete in stable cysts. These differences are not correlated with nucleic acid level, as both kinds of cysts contain approximately equal amounts of

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1961.tb01212.x

出版商:Blackwell Publishing Ltd    

年代:1961

数据来源: WILEY

摘要:

Thein vivoabsorption spectra of the chloroplast and eyespot ofEuglena graciliswere obtained by microspectro‐photometry. The average chloroplast absorption spectrum shows major peaks at 430‐43S and 675‐685 mμ. Thefine structuredetails of chlorophyllàshow peaks at 675, 685 and 695 mμ. The average eyespot absorption spectrum shows major absorption in the region of 460‐490 mμ, and two additional peaks near 510 and around 530 mμ with lesser peaks at 430 and 630 mμ. Some of these same absorption peaks were obtained for the eyespot ofE. granulataand the “hematochrome flecks.” The eyespot spectrum indicates that probably more than one ca‐rotenoid is present and that a correlation exists between the eyespot absorption spectrum and theEuglenaphotota

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1961.tb01213.x

出版商:Blackwell Publishing Ltd    

年代:1961

数据来源: WILEY

摘要:

DL‐serine, DL‐methionine or DL‐serine + DL‐methionine in excess inhibited the growth ofTetrahymena pyriformisH. Excess serine was most inhibitory at high concentration of folic acid, whereas the effect of excess methionine or methionine + serine was most pronounced at low levels of folic acid. Inhibition due to excess serine was relieved by raising the level of methionine or by adding pyrimethamine to lower the effective folic acid level, and was intensified by adding Dl.‐ethionine or by raising the level of folic acid. Similarly, inhibition due to excess methionine was relieved by supplying more serine or adding DL‐ethionine (which reduced the amount of available methionine) and was intensified by adding pyrimethamine. Inhibition by excess methionine + serine was reversed by increasing threonine, provided there was ample guanine present. Low levels of guanine or the presence of 8‐azaguanine prevented this reversal. Comparisons are made with the w

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1961.tb01214.x

出版商:Blackwell Publishing Ltd    

年代:1961

数据来源: WILEY

摘要:

Resistance to sulfanilamide has persisted in a strain ofChilomonas Parameciumfor 255 transfers (63 months) in a drug‐free medium. In attempts to modify resistance, stocks derived from sulfonamide‐resistant and normal strains have been acclimatized to and then maintained in media containingp‐aminobenzoic acid at 5.0, 10.0, 15.0 and 20.0 mgJ100 ml. Each PABA‐acclimatized strain was more susceptible to sulfanilamide than its parent stock. In other words, sulfanil‐amide‐resistant strains lost their resistance and normal strains became hypersensitive. One strain, adapted first to sulfanilamide, subsequently to PABA (15 mgJ100 ml) and again to sulfanilamide, showed a loss of and finally a restoration of sui‐fonamide‐resistance (but to a degree somewhat lower than the

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1961.tb01215.x

出版商:Blackwell Publishing Ltd    

年代:1961

数据来源: WILEY

摘要:

Total lipids of several protozoa were determined and found higher than in most other microorganisms. The lipid content in a phytoflagellate,Ochromonas malhamensis, could be increased by excess nicotinic acid or deficiency in nitrogen supply. Cell multiplication and lipid synthesis were unaffected by inhibitors of vitamin synthesis such as penicillamine, pan‐toyltaurine, or pyridine‐3‐sulfonic acid, up to 100 mg%. The phytoflagellates,O. danica, O. malhamensis, Euglena gracilis, and the photosynthetic bacteriumChlorobium limkolacontained large quantities of non‐saponifiable lipids: ergesterol was identified as a major component of this lipid fraction. Sterols were not found in the bacteria,Streptococcus faecalis, Rhodopseudomonas palustris; the algae.Cyanidium calidarnm. Anacystis nidulans, andPorphyridium cruentum; and the protozoanTetrahymena pyr

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1961.tb01216.x

出版商:Blackwell Publishing Ltd    

年代:1961

数据来源: WILEY

摘要:

Autogamy inFrontonia leucasis described for the first time. The process appears to occur at irregular intervals. From 7 to 10% of the individuals are affected. The beginning of autogamy is marked by a swelling of all the micronuclei which take part in the first two maturation divisions. The third division however affects only one of the second division products. Occasionally two or three may divide. A paroral cone is not prominent. But a small area close to the peristome is distinguishable as the region where the pronuclei fuse. The syn‐karyon divides four times. Some of the division products disintegrate, after which 8 to 9 bodies are left which become differentiated into 4 to 5 macronuclear anlagen and 4 micro‐nuclei. Mitotic division of the micronuclei results in their increase in number in the daughter individuals after metagamic divisions. Changes in the macronucleus during autogamy consist in its fragmentation and later absorption in the cytoplasm. There is some indirect evidence of a relationship between the dissolution of the old macronucleus and the development of the

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1961.tb01217.x

出版商:Blackwell Publishing Ltd    

年代:1961

数据来源: WILEY

摘要:

An amicronucleate clone ofTetrahymena pyrijormishas been found among the asexual progeny of irradiated cells of strain EU 6000 (variety 6, mating type I). Log‐phase cells of this clone, designated EU 6525, have a mean generation time (6.0 hr) longer than that of the micronucleate strain, EU 6000 (2.9 hr). Further irradiation studies of strain EU 6000 indicate that the recovery of viable amicronucleate populations is rare although many amicronucleate cells are found among surviving progeny.1Attempts to introduce micronuclei into amicronucleate cells of strain EU 6525 by conjugation have been made. Micronucleate lines are obtained from amicronu create pair members only in low frequency. These results, considered together with those of other workers, suggest that some change in the state of the cell, additional to the physical loss (or gain) of the micronucleus, must occur before viable amicronucleate clones can be obtained from micronucleate cells, or before amicronucleate cells can produce viable micronucleate lineages. An alteration in mean generation time may be a reflection of this change, or it may simply be a direct consequence of micronuclear removal. The results further imply that the ciliate micronucleus unquestionably contributes information to the cell during asexual growth and reproductio

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1961.tb01218.x

出版商:Blackwell Publishing Ltd    

年代:1961

数据来源: WILEY