摘要:

ABSTRACT.This work provides the first study of North Pacific planktonic ciliates by quantitative protargol staining. Triplicate water bottle samples were collected at a depth of 2 m (above the shallow pycnocline) at six stations in Indian Arm, British Columbia, on February 15, 1990, and February 26, 1991. Thirty‐six ciliate species were observed. Six new species are described from protargolstained specimens:Strombidium lynnin. sp.,Strombidium taylorin. sp.,Strombidium basimorphumn. sp.,Slrombidiurn ventropinnumn. sp.,Strobilidium undinumn. sp., andUrotricha cyrtonucleatan. sp.Ciliate abundance varied significantly (ANOVA, α= 0.05) between sampling sites, ranging from 550 to 6,800 cells/liter in 1990 and from 1,800 to 7,900 cells/liter in 1991. Biomass also varied significantly (ANOVA, α= 0.05) ranging from 3.7 × 105to 3.3 × 106pg carbon/liter in 1990 and 3.04 × 106− 6.97 × 106pg carbon/liter in 1991. Putative prey were enumerated in three size fractions (1.5–5 μm, 5–10 μm and 10–25 μm). The source of variation in ciliate abundance and biomass was not identified. Parameters of salinity, temperature, putative prey, chlorophyllaand pycnocline depth did not significantly correlate with ciliate biomass or a

ISSN:1066-5234    

DOI:10.1111/j.1550-7408.1993.tb06105.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

ABSTRACT.Miamiensis avidusMa/2 is a marine polymorphic scuticociliate. Eight strains of philasterine scuticociliates, currently in culture at the American Type Culture Collection (ATCC), were shown to produce a soluble factor that induces macrostomy in Ma/ 2:Miamlensis avidus(Ma and Ma/2),Paranophryssp. (1–1),Parauronema acutum(110–3).Anophtyoides soldoi(116–1),Anophryoidessp. (33–8).Merunophryssp. (113–8), andParanophryssp. (34–7). Of the strains tested,Paranophrysstrain 1–1 showed the highest induction of transformation, although all eight strains showed statistically signific

ISSN:1066-5234    

DOI:10.1111/j.1550-7408.1993.tb06106.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

ABSTRACT.We describe a new mass isolation procedure for both pure and stage‐specific phagosomes fromTetrahymena thermophila. We prepared magnetic iron dextran particles about 1 μm in diameter to label the phagosomes. The oral apparatus of the cells concentrated these particles so readily that after 1 min the majority of the cells had formed a single phagosome. A short wash removed non‐ingested particles, enabling us to follow the age‐dependent changes of a single labeled phagosome through the cell. Phagosomes of different ages, including very young and nascent phagosomes, were removed easily from the non‐magnetic cell debris of mechanically homogenized cells by means of a permanent magnet. The isolated phagosomes are pure as tested by enzymatic assays and light and electron microscopy. Since the yield of pure phagosomes of all ages is high (∼ 90%), this method could be generally applied for phagosome isolation fro

ISSN:1066-5234    

DOI:10.1111/j.1550-7408.1993.tb06107.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

ABSTRACT.A clinical isolateof Acunthamoeba polyphagu, associated withAcunthamoebukeratitis, was used for in vitro evaluation of antiamebic activity of selected azole compounds. Those antimicrobials tested included clotrimazole, bifonazole, fluconazole, itraconazole, and ketoconazole. The drugs were tested at varying concentrations on axenic trophic amebas and MgC12,‐induced cysts. On the basis of their effects on the two stages in the ameba life‐cycle, clotrimazole and bifonazole were the more promising of the azoles screened but, at concentrations tested, were amebastatic rather than amebicidal. Other strains ofA. polyphagaand species ofAcunthamoebuwere used for comparing variation in response to these and other antimicrobial age

ISSN:1066-5234    

DOI:10.1111/j.1550-7408.1993.tb06108.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

ABSTRACT.Expression of a 21 kDa determinant (Pbs21), first detected on the surface of ookinetes, and of the circumsporozoite protein (CSP) was studied by immunofluorescence and Western blots during the developmental cycle ofPlasmodium bergheiin the mosquitoA nopheles stephensi. The expression of Pbs21 was predominantly localised on the ookinete surface one day after the infectious blood meal, and thereafter reactivity declined to a minimum on days 2 and 3, the time of onset of oocyst development. A gradual increase in fluorescence was observed on the oocysts from day 6 that was retained until day 17 post‐infection. In contrast, sporozoites released from oocysts or salivary glands showed little or no antibody labelling with anti‐Pbs21. Circumsporozoite protein was not detectable in any rnidgut preparations until 5–6 days after feeding, when reactivity was observed against immature oocysts. Expression then continued and increased throughout oocyst and sporozoite development. Western blots confirmed that Pbs21 was expressed minimally during the oocyst development but was not detectable in sporozoites. Co‐localisation of anti‐Pbs21 and anti‐CSP monoclonal antibodies to the 50 kDa and 60 kDa bands in Western blots of sporozoite suggests immunological cross‐reactivity between the CSP and the anti‐21

ISSN:1066-5234    

DOI:10.1111/j.1550-7408.1993.tb06109.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

ABSTRACT.Trypanosomatids isolated from corn seeds and from digestive tract and salivary glands ofLeptoglossus zonatus(Hemiptera, Coreidae) were obtained in pure cultures. In experimental transmission, the flagellates present in naturally infected insects were able to infect laboratory‐raised corn. A simplified liquid culture medium was established that increased parasite yield three‐ to five‐fold. Cultured and cloned parasites, and forms found in insects and corn as well, were studied by light and electron microscopy. A remarkable finding was the observation that the cultured strain 163M bears a surface coat similar to that observed in naturally occurring African trypanosomes. but not observed in trypanosomes in vitro. Based on the biochemical characteristics of the arknine‐ornithine cycle and on the presence of this cell coat, we propose that the strain 163M is a new species and name itHerpetomonas macghe

ISSN:1066-5234    

DOI:10.1111/j.1550-7408.1993.tb06110.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

ABSTRACT.Sinefungin, an antifungal and antiparasitic nucleoside antibiotic, is a very potent antileishmanial agent both in vitro and in vivo. This molecule, structurally related to S‐adenosylmethionine, is a good competitive inhibitor of methyltransferases in vitro. The aim of this report is to analyze the impact of sinefungin on methylation pattern and the subcellular localisation of methyl groups and various methylases in promastigotesof Leishmania donovani. We have shown the presence of various methylated macromolecules in different subcellular fractions, with somewhat higher concentration in membrane fraction. In vitro, sinefungin inhibits the three main protein methylases, but in cells cultured in its presence the protein carboxylmethylations are specifically inhibite

ISSN:1066-5234    

DOI:10.1111/j.1550-7408.1993.tb06111.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

ABSTRACT.The kinetics of lysosomal enzyme acquisition by newly formed phagosomes was studied by following the rate of digestion of radiolabeled yeast fed toAcanthamoeba. The distribution of hydrolases among phagosomes was assessed by electron microscopic acid phosphatase cytochemistry and by measurement of three glycosidases in isolated early and late phagosomes. The results show that compartmentalization of hydrolases limit the digestion of large phagocytic loads. The hydrolases appear to be sequestered into the early phagosomes and not to be distributed either by small vesicle transport or phagosome‐phagosome fusion to those formed later. We infer from these results that newly internalized surface membrane in phagosomes is not rapidly randomized with internal pools, but is recycled to the surface as a function of the digestive proces

ISSN:1066-5234    

DOI:10.1111/j.1550-7408.1993.tb06112.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

ABSTRACT.A soluble enzyme amylopectin synthase (UDP‐glucose‐α 1,4‐glucan α‐4‐glucosyltransferase) which transfers glucose from uridine 5′‐diphosphate glucose (UDP‐glucose) to a primer to form α‐I,4‐glucosyl linkages has been identified in the extracts of unsporulated oocysts ofEimeria tenella. UDP‐glucose and not ADP‐glucose was the most active glucosyl donor. Corn amylopectin, rabbit liver glycogen, oyster glycogen and corn starch served as primers; the latter two were less efficient. The enzyme has an apparent pH optimum of 7.5 and exhibited typical Michaelis‐Menten kinetics with dependence on both the primer and substrate concentrations. The Michaelis constants (Km). with respect to UDP‐glucose, was 0.5 mM; and 0.25 mg/ml and 1.25 mg/ml with respect to amylopectin and rabbit liver glycogen. The product formed by the reaction was predominantly a glucan containing α‐1,4 linkages. The specificity of the enzyme suggests that this enzyme is similar to glycogen synthase in eukaryotes and has been designated as amylopectin synthase (UDP‐glucose‐

ISSN:1066-5234    

DOI:10.1111/j.1550-7408.1993.tb06113.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

ABSTRACT.The amoebae, a phenotypically diverse, paraphyletic group of protists, have been largely neglected by molecular phy‐logeneticists. To better understand the evolution of amoebae, we sequenced and analyzed the 16S‐like ribosomal RNA genes of three vahlkampfiid amoebae:Paratetramitus jugosus, Tetramitus rostratusandVahlkampfia lobospinosa. The Vahlkampfiidae lineage is monophyletic, branches early along the eukaryotic line of descent, and is not a close relative of the multicellular amoebae that also reversibly transform from amoebae to flagella

ISSN:1066-5234    

DOI:10.1111/j.1550-7408.1993.tb06114.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY