Restoration of virulence of axenically cultivated Entamoeba histolytica by cholesterol

1978 ◽  
Vol 24 (1) ◽  
pp. 63-65 ◽  
Author(s):  
E. Meerovitch ◽  
E. Ghadirian
Keyword(s):  
Entamoeba Histolytica ◽  
Culture Medium ◽  
Axenic Culture ◽  
The Other ◽  
In Vitro Cultivation ◽  
The Past ◽  
Cholesterol Treatment ◽  
Long Time ◽  
Axenic Conditions

The lost pathogenicity of two strains of Entamoeba histolytica, one isolated in 1924 and the other in 1967, grown in axenic culture for the past 5 and 6 years respectively, was restored by supplementing the culture medium with cholesterol through a number of transfers. The number of passages in the cholesterol-supplemented medium, necessary to restore a certain degree of pathogenicity of the two strains in hamsters, was proportional to the total time of in vitro cultivation of the strain, and not just the time of cultivation under axenic conditions. Pathogenicity, once restored, persisted for a long time after cholesterol treatment was stopped.

Effect of phosphatidylcholine–cholesterol liposomes on Entamoeba histolytica virulence

2010 ◽  
Vol 56 (12) ◽  
pp. 987-995 ◽  
Author(s):  
Jesús Serrano-Luna ◽  
Manuel Gutiérrez-Meza ◽  
Ricardo Mejía-Zepeda ◽  
Silvia Galindo-Gómez ◽  
Víctor Tsutsumi ◽  
...  
Keyword(s):  
Entamoeba Histolytica ◽  
Culture Medium ◽  
In Vitro Cultivation ◽  
Biological Functions ◽  
Axenic Cultures ◽  
Term Maintenance ◽  
Histolytica Strain

Trophozoites of Entamoeba histolytica HM-1:IMSS become less virulent after long-term maintenance in axenic cultures. The factors responsible for the loss of virulence during in vitro cultivation remain unclear. However, it is known that in vitro cultivation of amoeba in culture medium supplemented with cholesterol restores their virulence. In this study, we analyzed the effect of adding phosphatidylcholine–cholesterol (PC–Chol) liposomes to the culture medium and evaluated the effect of this lipid on various biochemical and biological functions of E. histolytica HM-1:IMSS in terms of its virulence. The addition of PC–Chol liposomes to the culture medium maintained the virulence of these parasites against hamster liver at the same level as the original virulent E. histolytica strain, even though these amoebae were maintained without passage through hamster liver for 18 months. The trophozoites also showed increased endocytosis, erythrophagocytosis, and carbohydrate residue expression on the amoebic surface. Protease activities were also modified by the presence of cholesterol in the culture medium. These findings indicate the capacity of cholesterol to preserve amoeba virulence and provide an alternative method for the maintenance of virulent E. histolytica trophozoites without the need for in vivo procedures.

scholarly journals Bio-Guided Isolation of Antimalarial Metabolites from the Coculture of Two Red Sea Sponge-Derived Actinokineospora and Rhodococcus spp.

Marine Drugs ◽  
2021 ◽  
Vol 19 (2) ◽  
pp. 109
Author(s):  
Hani A. Alhadrami ◽  
Bathini Thissera ◽  
Marwa H. A. Hassan ◽  
Fathy A. Behery ◽  
Che Julius Ngwa ◽  
...  
Keyword(s):  
Red Sea ◽  
Antimalarial Activity ◽  
Axenic Culture ◽  
Trna Synthetase ◽  
Structural Motif ◽  
Natural Habitats ◽  
Signalling Molecules ◽  
Chemical Signalling ◽  
Axenic Conditions

Coculture is a productive technique to trigger microbes’ biosynthetic capacity by mimicking the natural habitats’ features principally by competition for food and space and interspecies cross-talks. Mixed cultivation of two Red Sea-derived actinobacteria, Actinokineospora spheciospongiae strain EG49 and Rhodococcus sp. UR59, resulted in the induction of several non-traced metabolites in their axenic cultures, which were detected using LC–HRMS metabolomics analysis. Antimalarial guided isolation of the cocultured fermentation led to the isolation of the angucyclines actinosporins E (1), H (2), G (3), tetragulol (5) and the anthraquinone capillasterquinone B (6), which were not reported under axenic conditions. Interestingly, actinosporins were previously induced when the axenic culture of the Actinokineospora spheciospongiae strain EG49 was treated with signalling molecule N-acetyl-d-glucosamine (GluNAc); this finding confirmed the effectiveness of coculture in the discovery of microbial metabolites yet to be discovered in the axenic fermentation with the potential that could be comparable to adding chemical signalling molecules in the fermentation flask. The isolated angucycline and anthraquinone compounds exhibited in vitro antimalarial activity and good biding affinity against lysyl-tRNA synthetase (PfKRS1), highlighting their potential developability as new antimalarial structural motif.

Long Time Coming: Prospects for Democracy in Iraq

2009 ◽  
Vol 33 (4) ◽  
pp. 115-148 ◽  
Author(s):  
Bruce E. Moon
Keyword(s):  
Nineteenth Century ◽  
The Other ◽  
Democratic Transitions ◽  
Quarter Century ◽  
The Past ◽  
Political Experience ◽  
Long Time ◽  
Time Required ◽  
Established Democracies

Prospects for democracy in Iraq should be assessed in light of the historical precedents of nations with comparable political experiences. Saddam Hussein's Iraq was an unusually extreme autocracy, which lasted an unusually long time. Since the end of the nineteenth century, only thirty nations have experienced an autocracy as extreme as Iraq's for a period exceeding two decades. The subsequent political experience of those nations offers a pessimistic forecast for Iraq and similar nations. Only seven of the thirty are now democratic, and only two of them have become established democracies; the democratic experiments in the other five are still in progress. Among the seven, the average time required to transit the path from extreme autocracy to coherent, albeit precarious, democracy has been fifty years, and only two have managed this transition in fewer than twenty-five years. Even this sober assessment is probably too optimistic, because Iraq lacks the structural conditions that theory and evidence indicate have been necessary for successful democratic transitions in the past. Thus, the odds of Iraq achieving democracy in the next quarter century are close to zero, at best about two in thirty, but probably far less.

Métabolisme de l'acide indolyl-3-acétique dans les cultures de cellules d'Acer pseudoplatanus cultivés in vitro

1977 ◽  
Vol 55 (19) ◽  
pp. 2530-2534 ◽  
Author(s):  
F. Maillard ◽  
J.-P. Zrÿd
Keyword(s):  
Cell Wall ◽  
Acetic Acid ◽  
Culture Medium ◽  
Degradation Products ◽  
Cell Suspensions ◽  
The Other ◽  
Acer Pseudoplatanus ◽  
Kinetics Of

Incubation of cell suspensions of sycamore (Acer pseudoplatanus) with β-indoyl-3-acetic acid (IAA) first led to the formation of IAA-glycosides, then to that of IAA-aspartate. Great differences are observed between the kinetics of IAA transformed by two distinct strains: one, auxin dependent (S), the other, auxin independent (MB). Other degradation products are only found in the culture medium. The localization of IAA-degrading systems in the cell wall is postulated. The auxin requirement of the S strain is discussed.

scholarly journals Oviposition by Schistosoma mansoni during in vitro cultivation

1996 ◽  
Vol 38 (6) ◽  
pp. 423-426 ◽  
Author(s):  
Leo Roberto Barth ◽  
Ana Paula Morais Fernandes ◽  
Vanderlei Rodrigues
Keyword(s):  
Schistosoma Mansoni ◽  
Egg Production ◽  
Culture Medium ◽  
Parasite Development ◽  
In Vitro Cultivation ◽  
Progressive Reduction ◽  
Maximum Period ◽  
Medium Time ◽  
Kinetics Of

Observation of Schistosoma mansoni oviposition during in vitro culture of adult worms for a maximum period of 10 days showed three well distinct phases in the kinetics of oviposition: an initial phase with low egg production, a period of maximum oviposition and finally a progressive reduction in the number of eggs during the late phases of culture. The kinetics of oviposition and the number of eggs laid by the parasites are influenced by the number of worm pairs per amount of RPMI 1640 medium, time of parasite development in the vertebrate host and type of serum utilized in the culture medium.

Human decidua synthesizes placental protein 14 (PP 14) in vitro

1986 ◽  
Vol 112 (2) ◽  
pp. 271-277 ◽  
Author(s):  
Mervi Julkunen
Keyword(s):  
Tissue Culture ◽  
Culture Medium ◽  
The Other ◽  
Term Pregnancy ◽  
Tissue Explants ◽  
Placental Protein 14 ◽  
Foetal Membranes ◽  
Placental Protein ◽  
Human Decidua

Abstract. Human decidua was found to synthesize and secrete placental protein 14 (PP14). The presence of PP14 in tissue explants of decidua, foetal membranes and placenta from term pregnancy was demonstrated by radioimmunoassay. The PP14 content in decidua (1300 ±410 ng/100 mg tissue) was higher than in chorion (570 ± 120 ng/100 mg; P < 0.01), amnion (240 ± 100 ng/100 mg; P < 0.001) or placenta (300 ± 130 ng/100 mg; P< 0.001). Three to 36 times more PP14 was released into culture medium by decidual explants compared with the other tissues, and cycloheximide decreased this release by 39%. Placental tissues released hardly any PP14. Decidual synthesis of PP14 was demonstrated by incorporation of [35S]methionine into immunoprecipitable PP14 in tissue culture.

Partial purification of antigens collected during in vitro cultivation of the larval stages of Taenia pisiformis

Parasitology ◽  
1976 ◽  
Vol 72 (3) ◽  
pp. 269-279 ◽  
Author(s):  
M. D. Rickard ◽  
J. C. Katiyar
Keyword(s):  
Protective Immunity ◽  
Culture Medium ◽  
Serum Proteins ◽  
Skin Tests ◽  
Rabbit Serum ◽  
Partial Purification ◽  
In Vitro Cultivation ◽  
Normal Rabbit Serum ◽  
Skin Reactions

SummaryLarvae of Taenia pisiformis were cultured in vitro in medium containing 2·5, 5 or 20% (v/v) of normal rabbit serum (NRS). Greatest development occurred in 20% NRS, and the potency of antigens collected in medium from each culture tested by intradermal (i/d) skin tests in infected rabbits paralleled the in vitro growth rate of larvae. ‘Culture’ antigens from 5% NRS stimulated good immunity in rabbits to a challenge infection with T. pisiformis eggs, although they were poorly reactive in skin tests.T. pisiformis larvae were also cultured in 10% (v/v) of nitrates of serum reduced to one-half of its volume by passage through 300 000 MW cut oif (XM300F) or 100000 MW cut off (XM100F) ultrafiltration membranes. Larvae cultured using XM300F had growth rates comparable with those cultured in 20% NRS, and the antigens released into the culture medium had equal potency in i/d tests and in stimulating protective immunity in rabbits. Larvae did not develop in XM100F orproduce skin-reactive or protective antigens.Crude ‘culture’ antigen from cultures in 20% NRS was separated into 4 fractions by nitration on Sephadex G200. All of these fractions gave i/d skin reactions in infected rabbits. Fraction 3 (F3) was the most active, but was shown by acrylamide gel electrophoresis and immunoelectrophoresis to be highly contaminated with rabbit serum proteins. F3 was separated into fractions on DEAE-Sephadex A50, and the third fraction from this was as active as the original culture medium in i/d skin tests, but had only 5% of the original protein concentration. Electrophoresis demonstrated few serum contaminants, and 2 indistinct protein bands that were not present in a similar fraction of NRS.Neither Sephadex G200 F3 nor DEAE-Sephadex F3 stimulated protective immunity in rabbits, suggesting that antigens stimulating immunity against the establishment of T. pisiformis in rabbits and those provoking cell-mediated immune reactions may be different.

Terpenoid quinones and steroids in the nutrition of Oxyrrhis marina

1971 ◽  
Vol 51 (2) ◽  
pp. 455-470 ◽  
Author(s):  
M. R. Droop ◽  
J. F. Pennock
Keyword(s):  
Growth Factors ◽  
Culture Medium ◽  
Water Soluble ◽  
The Other ◽  
Natural Sources ◽  
Oxyrrhis Marina ◽  
Nutritional Study ◽  
Axenic Conditions ◽  
Micro Organisms ◽  
Axenic Cultivation

INTRODUCTIONOxyrrhis marina Dujardin is among the few phagotrophic micro-organisms, and the only dinoflagellate with this mode of nutrition, to have been cultivated under axenic conditions. In common with most other phagotrophs studied, Oxyrrhis had to be supplied with a natural source of lipid growth factors for axenic cultivation, lemon rind or grass extracts in this instance (Droop, 1959). The eventual replacement of these natural sources by ubiquinone (Droop & Doyle, 1966) cleared the way for the development of a completely denned culture medium for Oxyrrhis and the completion of the nutritional study, the water-soluble nutrients having been fully worked out previously (Droop, 1959). However, identification of this requirement immediately raises two questions. The answer to the first, whether ubiquinone is the only lipid required, appears to be in the negative, and the details of an additional, fairly specific, steroid requirement are presented in the second part of this paper. The other question concerns the specificity of the quinone requirement. Is the quinone merely a convenient source of the benzene ring – mammals require at least one aromatic compound in the diet – or does it act as a true growth factor, in which case the requirement would be unique and would have more than protozoological interest?

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