摘要:

SUMMARY.Six species ofPolytomellawere isolated in pure culture from ecologically very different places where they may have only survived as cysts, but one of them was found in enormous numbers between rotting hemp in Italy. This shows that apparent rarity of the members of the genus may be caused by the restricted occurrence of suitable conditions which are characterized by abundance of organic nutrients and a certain low degree of acidity.The species differ only in minor morphological features, except for one of them which has for instance an eye‐spot. This is also the only one the nutrition of which deviates from that of the rest.Under auxotrophic conditions with acetate as the only organic nutrient except thiamine, and in media containing acetate, peptone and yeast extract, growth is satisfactory, but it becomes luxuriant in yeast digest even without addition of an independent energy and carbon source. Starch is then still deposited but to some extent replaced by oil.The production of cysts, which survive desiccation, is an important ecological featur

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1955.tb02413.x

出版商:Blackwell Publishing Ltd    

年代:1955

数据来源: WILEY

摘要:

SUMMARY.An unsporulated oocyst ofEimeria brunettiencountered at random in a mild infection would probably be 13.8 to 33.7 μ long and 12.4 to 26.2 μ wide. Its shape‐index (length/width) would probably lie between the extremes of 1.0 and 1.6. Its dimensions would probably not change significantly during the sporulation process. If a sample of the oocysts randomly encountered happened to be the progeny of a single inoculation, their mean size would depend, among other things, on the day of the patent period the sample was taken, as well as on certain undetermined factors in the individual host; but their mean length would probably lie between 21.1 μ and 27.1 μ and their mean width between 17.5 μ and 21.7 μ. The mean dimensions would probably be smaller early in the patent period of the infection than later.By a certain process of reasoning it was deduced that the individual components of an “ideal” sample of oocysts ofE. brunettiwould range from 18.4 μ to 28.4 μ in length and from 15.2 μ to 23.9 μ in width; their mean dimensions with standard deviations would be about 23.4 ± 2.0 μ by 19.7 ± 1.7 μ, and their shape‐indexes would range from 1.0 to 1.4 and average about 1.19. The lengths, widths, and shape‐indexes of the oocysts would usually describe unimodal frequency distribution curves, most of them near‐symmetrical. The mean size of the matured spores produced inside such oocysts would probably be close to 13.2 by 7.5 μ, and their shape‐index near 1.76. As a matter of fact, such a sample would be encountered only by pure chance, because the size of the oocyst ofE. brunettiremains an undetermined quantity until it is translated into a veritable definition that takes account not only of its variability under one set of conditions, but also of its capacity to respond to other conditions, among them the size of the inoculation, the influence of the individual host, and the day of the infection.It would be hazardous to discriminate between or among species of coccidia on the basis of oocyst measurements, particularly when they lack conspicuous diagnostic morphological or physiological features of another nature. As Cheissin reflected, observations on a single finding of oocysts, particularly when they are sparse in numbers, are not a substitute for repeated observations on oocysts issuing from the host at different times an

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1955.tb02414.x

出版商:Blackwell Publishing Ltd    

年代:1955

数据来源: WILEY

摘要:

SUMMARY.The various stages of a new genus of schizogregarineTriboliocystisgarnhami are described in detail. This parasite was found in the fat bodies of the larvae of a culture ofTribolium castaneumand caused death of the larvae when infection was heavy. The systematic position ofT. garnhamiis discussed, and a short description is given of a new microsporidianNosema buckleyifound in a single pupa ofTribolium.

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1955.tb02415.x

出版商:Blackwell Publishing Ltd    

年代:1955

数据来源: WILEY

摘要:

SUMMARY.The colorless phytomonad,Polytomella caeca, has been grown in simple media with each of the following as the sole energy source: propionate, butyrate, valerate; butyl and amyl alcohols; DL‐glyceraldehyde, and alpha‐ketoglutaric acid. These compounds did not support growth in simple media: caproate, caprylic acid, isobutyrate, propyl, isopropyl and isobutyl alcohols. At present, C5, seems to be the limit of length of the fatty acids that are suitable carbon and energy sources. Iso compounds were not utilized. The pH in the acid media increased during incubation; that in alcohol media decrea

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1955.tb02416.x

出版商:Blackwell Publishing Ltd    

年代:1955

数据来源: WILEY

摘要:

SUMMARY.Susceptible ducklings were exposed to natural infection during a limited time, and infections of supposedly known duration were obtained. Slides of tissues from these ducklings were prepared by common histological techniques. Comparative materials were provided by cooperators. On the basis of study of these tissues what seems a logical description of development of megaloschizonts ofLeucocytozoon simondiwas formulated.The earliest stage found was the trophozoite. There is no evidence of schizogony in this form; the only internal structure is the nucleus. Prior to any schizogony there is a marked increase in the amount of chromatin in the nucleus, especially on the periphery.It is hypothesized that as the chromatin increases, buds are evaginated from the margin of what may then be called the central body and are set off to form spherical primary cytomeres. The chromatin of primary cytomeres first diffuses and then proliferates to form peripheral clusters. These clusters of chromatin separate to form secondary cytomeres which continue to multiply in the same manner.The production of cytomeres by the central body and by division of primary and secondary cytomeres eventually fills the cytoplasmic area of the megaloschizont. Apparently pressure within the schizont then shapes the course of further development. The central body ceases to function as a primordium and becomes compressed. The multiplying cytomeres become smaller and more granular in appearance, and their chromatin becomes more concentrated. Merozoite‐like bodies are eventually produced. These reproduce until the central body is greatly compressed and the membrane enclosing the megaloschizont is ruptured and releases the merozoite

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1955.tb02417.x

出版商:Blackwell Publishing Ltd    

年代:1955

数据来源: WILEY

摘要:

SUMMARY.The mitochondria of living, unstainedPelomyxa carolinensisare homogeneous, nonrefractile bodies and occur as spheres, short rods, dumbbell forms or elongated rods. All forms are distributed uniformly throughout the cytoplasm, except for characteristic accumulations around the contractile vacuoles and small food vacuoles. Mitochondria were never observed within food vacuoles, nor in intimate contact with large food vacuoles containing recently ingested paramecia.Aqueous solutions (1:200,000) of Janus green B, Janus blue, and Janus red stained the mitochondria. After 12 hours in Janus green B and Janus blue or 24 hours in Janus red, the mitochondrion appears as a differentiated structure with the stain localized in eccentric granules or crescentic areas. Aqueous solutions of Janus black (1:200,000), amethyst violet (1:200,000) and Rhodamine B (1:50,000) stained only food vacuoles within the organisms.Dumbbell forms and elongated rods, often interpreted as division stages, were continuously observed in the living organism. These observations failed to reveal any division process.Sectioned material was prepared from animals fixed in Champy's, Regaud's, Altmann's and Helly's fluids, as well as in a fixative composed of equal parts of 1% (w/v) chromic acid and 2% (w/v) osmium tetroxide. Excellent results were obtained with Champy and chrom‐osmic fixation, while the other fixatives proved to be of little valu

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1955.tb02418.x

出版商:Blackwell Publishing Ltd    

年代:1955

数据来源: WILEY

摘要:

SUMMARY.Seven hundred twenty samples of water from 46 states and the province of Ontario, Canada, were collected and examined forTetrahymena pyriformis.Thirty‐four hundred clonal cultures of the ciliate were isolated from the 154 (21%) positive samples and grown axenically in peptone medium.The breeding behavior of strains from these 154, sources was investigated by mixing clonal cultures in various combinations. Eight sources yielded selfing strains and 52 yielded strains capable of mating only in certain combinations. Thirty new mating types in seven new non‐interbreeding varieties were discovered. Ninety of the 154 collections yielded non‐conjugating strains. Fifty of these proved to be amicronucleate.Distribution of variety 2 organisms was the most widespread; 22 collections from 11 states and Ontario, Canada, were obtained. Variety 3 was collected 14 times from seven states. Other varieties were found less often. The ciliate was found about as often in running as in standing water, but certain varieties were found predominantly in one or the other ha

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1955.tb02419.x

出版商:Blackwell Publishing Ltd    

年代:1955

数据来源: WILEY

摘要:

SUMMARY.Gregarines were found for the first time in the honey beeApis melliferaL. in Venezuela. The parasites attacked the inner wall of the ventriculus of the adult bees, causing heavy losses in apiculture in October 1954 and June 1955. The disease produced was called gregarina disease of the honey bee (in Spanish “gregarinosis de la abeja

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1955.tb02420.x

出版商:Blackwell Publishing Ltd    

年代:1955

数据来源: WILEY

摘要:

SUMMARY.To avoid multiple centrifugation and considerable losses of material in preparing protozoa for paraffin and plastic embedding a simple method has been worked out, requiring only two centrifugations, one before and one after fixation. During the second centrifugation, which is done at 700 g for 10 minutes, the organisms form a cohesive pellet which may be removed from the centrifuge tube by means of a fine spatula and handled as a piece of tissue through the whole process of dehydration and embedding.

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1955.tb02421.x

出版商:Blackwell Publishing Ltd    

年代:1955

数据来源: WILEY