ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1986.tb05545.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

ABSTRACT.Drugs that interact with microtubules (colchicine and vinblastine) and microfilaments (cytochalasin B) partially inhibited cell growth and motility ofTritrichomonas foetus.Parasites incubated with these substances became rounded and cell division was blocked. Neither colchicine nor vinblastine disrupted the microtubules that form the peltar‐axostylar system. Any one of these drugs interfered with the net negative surface charge ofT. foetusas evaluated by determination of the cellular electrophoretic mobility (EPM). The decrease in the EPM of cytochalasin B‐treated cells was caused by dimethylsulfoxide, which was used as solvent. Untreated cells as well as cytochalasin B‐treated cells showed a uniform distribution of anionic sites on the plasma membrane as seen with cationized ferritin particles. In cells treated with colchicine or vinblastine the anionic sites were distributed in patches. These results are discussed in terms of participation of labile cytoplasmic microtubules and microfilaments in the control of the distribution of anionic sitecontaining macromolecules located on the cell surface ofT. f

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1986.tb05546.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

ABSTRACT.Naegleria fowleriamebae, but not those ofN. australiensis, N. gruberi, orN. lovaniensis, demonstrated enhanced motility when placed in proximity to mammalian cells. Amebae of nonpathogenic species ofNaegleria, however, were more motile in cell culture medium than the amebae ofN. fowleri.The locomotory response of highly pathogenic mouse‐passagedN. fowleriamebae to nerve cells was greater than axenically cultured amebae. The enhanced mobility elicited by whole nerve cells or disrupted nerve cells was not directed migration but chemokinetic.Naegleria fowleriresponded to disrupted neuroblastoma cells more vigorously than to disrupted African green monkey kidney (Vero) cell

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1986.tb05547.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

ABSTRACT.Immunological relationships between genera and species of microsporidia were examined by immunoblot analysis. Exospore polypeptides from twoNosemaspp., threeVairimorphaspp., and two undescribedVairimorpha‐like isolates were analyzed. Gel electrophoresis and immunoblot analysis revealed that a variety of polypeptides, mostly between 15,000 and 90,000 molecular weight, are present on the exospore. The threeVairimorphaspp. are closely related immunologically to each other, but less so to the two undescribedVairimorpha‐like isolates. The twoNosemaspp. are immunologically distant from each other and from theVairimorphaspp. Indirect evidence, however, indicated that many internal spore polypeptides present in both genera are similar. Cross‐reactivity between exospore polypeptides from entomophilic microsporidia and antisera to a mammalian microsporidium,Encephalitozoon cuniculi, was very limited. These results indicate that immunoblot analysis of exospore polypeptides may be employed to investigate the interrelatedness of microsporidian species, and that exospore polypeptides of some microsporidia are sufficiently diverse to be of immunodiagnostic

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1986.tb05548.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

ABSTRACT.Water‐soluble and 0.6 M KCl‐soluble protein fractions prepared fromTetrahymena pyriformis, when inoculated into mice, could effectively induce activated macrophages having the ability to killToxoplasma gondiiin vitro. This effect was not induced by other proteins tested, such as bovine serum albumin, pepsin from porcine stomach mucosa and chicken egg‐white lysozyme, nor by muramyl dipeptide (MDP), a potent immunoadjuvant. Five fractions obtained by DEAE‐Sephadex chromatography of the water‐soluble protein fraction were compared with regard to induction of toxoplasmacidal activity in macrophages. The first peak was most effective for activation of macrophages. Five fractions obtained by chromatography of the 0.6 M KCl‐soluble protein fraction were also examined and it was found that the first peak had the activity. No marked difference in activity was observed between the active fractions of water‐soluble and 0.6 M KCl‐soluble protein fractions. For practical use, we focused on the water‐soluble active fraction. The minimum effective dose of the active fraction was 100 μg and the fraction could activate macrophages directly in vitro. Four fractions obtained by gel filtration of the active fraction on Sephadex G‐200 were compared and the first peak had the activity. The first peak contained a single protein, revealed by SDS‐polyacrylamide gel electrophoresis; its apparent molec

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1986.tb05549.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

ABSTRACT.We have determined the complete nucleotide sequence of the coding region of the small subunit rRNA gene of the hypotrichous ciliateEuplotes aediculatus.It is 1882 nucleotides long and contains several inserts not present in the small subunit rRNA genes of the hypotrichsOxytricha novaandStylonychia pustulata.A comparison of the sequences suggests thatE. aediculatusis much less closely related to these other two hypotrichs than they are to each other. Although the gene sequence ofE. aediculatusis drifting more rapidly than those of these other two species, its faster evolutionary clock is not enough to account for the degree of difference between them.

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1986.tb05550.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

ABSTRACT.DNA is eliminated during development of the somatic MACronucleus from the germinal MICronucleus in the ciliated protozoan,Tetrahymena thermophila.Facultatively persistent sequences are a class of sequences that persist in the MAC DNA of some cell lines but are eliminated from the MAC DNA of other cell lines. One cloned MAC fragment contains a persistent sequence as well as sequences normally retained in the MAC. When this cloned fragment was used to construct MAC restriction maps of this region in cell lines whose MAC DNAs do, or do not, contain the persistent sequence, extensive variation in the map flanking this region was observed. The different DNA rearrangements of this MIC segment are epigenetically determined during or soon after MAC development. Moreover, different rearrangements may occur among the 45 copies of this MIC segment as a MAC is formed, resulting in polymorphisms that are later resolved by phenotypic assortment.

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1986.tb05551.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

ABSTRACT.One stock, GBC, has a maximum temperature of growth about 5°C lower than other recently collected stocks ofParamecium primaurelia.The resistant stocks (R) are able to grow continuously at 35°C while the sensitive stock (S) cells die within 48 h. The F1s of R x S crosses exhibited a cytoplasmic pattern of inheritance and all F2‐by‐autogamy lines derived from the S cytoplasmic parent are sensitive. The F2‐by‐autogamy lines cytoplasmically descended from the R parent were predominantly (93%) R in the initial assay. Upon reinvestigation one year later, only 64% of these lines were R, 9% were S, and 27% had a new phenotype, weak (W), intermediate between R and S. Backcrosses of W lines to both R and S strongly suggest that the W lines have normal cytoplasm (i.e. R) but also have nuclear gene(s) for temperature sensitivity that are derived from the original S stock. The delayed manifestation of the W phenotype is not u

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1986.tb05552.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

ABSTRACT.The combined action of cadmium and selenium was investigated in two unicellular marine phytoplankton organisms,Prorocentrum micansEhrbg. andCrypthecodinium cohniiBiecheler, in culture. When present simultaneously in low concentrations, the toxicity of Cd and Se is decreased (antagonism) whereas if one of these elements is present at high concentration, especially for a long period, their toxicity is increased (synergism) more than if they were separate. This interaction affected cell organelles in the following ways: vacuolation, development of chloroplast pyrenoids, and elicitation of lipid vesicles, starch vesicles, giant mitochondria, and lysosomes. Possible competition between these two elements for binding sites is discussed.

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1986.tb05553.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

ABSTRACT.The yield of the bacteriumEnterobacter aerogenesand the ciliateColpidium colpodawas dependent on initial phosphorus concentrations in batch cultures containing 125 or 250 mg/liter glutamate and 50–1000 μg/liter phosphorus. For both, yield per unit phosphorus declined at higher phosphorus concentrations. A marked decline in growth rate in bacterial cultures was coincident with the depletion of dissolved phosphorus and the development of rapid orthophosphate turnover times.Colpidiumintroduced to these cultures consumed about 16,000 bacteria/h/ciliate while multiplying exponentially and relieved phosphorus limitation, as indicated by a longer turnover‐time for phosphate. The longer turnover‐time was due to the reduction of bacterial numbers; in cultures with ciliates, bacteria appear to be more active in taking up phosphate, and much of the total phosphorus accumulates in ciliates. Ciliates released both inorganic and organic phosphorus, but the organic phosphorus did not accumulate to excess in the cultures to an extent that would indicate that it is less used by bacteria. Although ciliates release enough phosphorus to account for ca. 20% of the bacterial uptake, ciliates appear to behave as phosphorus sinks as much as phosphorus recyclers in these closed s

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1986.tb05554.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY