Invasion of mature and immature erythrocytes of CBA/Ca mice by a cloned line of Plasmodium chabaudi chabaudi

Parasitology ◽  
1989 ◽  
Vol 99 (2) ◽  
pp. 157-163 ◽  
Author(s):  
W. Jarra ◽  
K. N. Brown
Keyword(s):  
No Reduction ◽  
Plasmodium Chabaudi ◽  
Equal Frequency ◽  
Early Stages ◽  
Parasite Replication ◽  
Parasite Populations ◽  
Peak Parasitaemia

SummaryDuring the early stages of the primary Plasmodium chabaudi chabaudi AS parasitaemia in CBA/Ca mice this parasite invaded normocytes, but as the parasitaemia developed increasing numbers of parasites were seen within reticulocytes. During and just after peak parasitaemia, as further parasite replication was controlled, the ‘crisis’ phase ensued, mice became increasingly anaemic and reticulocyte numbers were markedly increased. As the parasitaemia was resolved during crisis in excess of 25% of parasites had invaded reticulocytes. In phenylhydrazine-pretreated mice with artificially high reticulocyte levels and infected with P. c. chabaudi AS, normocyte/reticulocyte invasion occurred with equal frequency. No reduction in the infectivity of parasite populations developing in reticulocytes was observed.

Protective immunity to erythrocytic Plasmodium chabaudi AS infection involves IFNγ-mediated responses and a cellular infiltrate to the liver

Parasitology ◽  
2000 ◽  
Vol 121 (5) ◽  
pp. 473-482 ◽  
Author(s):  
P. BALMER ◽  
J. ALEXANDER ◽  
R. S. PHILLIPS
Keyword(s):  
Mortality Rate ◽  
Adoptive Transfer ◽  
Protective Immunity ◽  
No Reduction ◽  
Cytological Analysis ◽  
Plasmodium Chabaudi ◽  
Cellular Infiltrate ◽  
Specific Igg ◽  
Deficient Mice

IFNγ receptor (IFNγR) deficient mice and IL-4 deficient mice were infected with blood-stage Plasmodium chabaudi AS in order to analyse the role of Th1 (IFNγ) and Th2 (IL-4)-associated cytokines in the development of protective immunity to the parasite. A high mortality rate and failure to reduce the primary parasitaemia to subpatent levels was observed in the IFNγR deficient mice. IL-4 deficient mice controlled a primary P. chabaudi AS infection in a similar manner to control mice and no mortality was observed. IFNγR deficient mice had a reduction in parasite-specific IgG and a significantly increased level of total IgE compared to control mice. There was no reduction in the level of parasite-specific IgG in IL-4 deficient mice. Cytological analysis of the cells present in the spleen and liver during the primary parasitaemia revealed a reduction in the numbers of lymphocytes, monocytes and polymorphonuclear (PMN) cells in the liver at the peak of parasitaemia in both IFNγR deficient mice and IL-4 deficient mice compared to control mice. Adoptive transfer studies demonstrated that cells isolated from the liver at day 11 post-infection could confer some protective immunity to P. chabaudi AS infection.

scholarly journals An enhanced toolkit for the generation of knockout and marker-free fluorescent Plasmodium chabaudi

2020 ◽  
Vol 5 ◽  
pp. 71
Author(s):  
Edward J Marr ◽  
Rachel M Milne ◽  
Burcu Anar ◽  
Gareth Girling ◽  
Frank Schwach ◽  
...  
Keyword(s):  
Marker Genes ◽  
Plasmodium Chabaudi ◽  
Chronic Infections ◽  
Selectable Marker Genes ◽  
Erythrocyte Invasion ◽  
Infection Dynamics ◽  
Marker Free ◽  
Parasite Replication

The rodent parasite Plasmodium chabaudi is an important in vivo model of malaria. The ability to produce chronic infections makes it particularly useful for investigating the development of anti-Plasmodium immunity, as well as features associated with parasite virulence during both the acute and chronic phases of infection. P. chabaudi also undergoes asexual maturation (schizogony) and erythrocyte invasion in culture, so offers an experimentally-amenable in vivo to in vitro model for studying gene function and drug activity during parasite replication. To extend the usefulness of this model, we have further optimised transfection protocols and plasmids for P. chabaudi and generated stable, fluorescent lines that are free from drug-selectable marker genes. These mother-lines show the same infection dynamics as wild-type parasites throughout the lifecycle in mice and mosquitoes; furthermore, their virulence can be increased by serial blood passage and reset by mosquito transmission. We have also adapted the large-insert, linear PlasmoGEM vectors that have revolutionised the scale of experimental genetics in another rodent malaria parasite and used these to generate barcoded P. chabaudi gene-deletion and –tagging vectors for transfection in our fluorescent P. chabaudi mother-lines. This produces a tool-kit of P. chabaudi lines, vectors and transfection approaches that will be of broad utility to the research community.

scholarly journals An enhanced toolkit for the generation of knockout and marker-free fluorescent Plasmodium chabaudi

2020 ◽  
Vol 5 ◽  
pp. 71 ◽  
Author(s):  
Edward J Marr ◽  
Rachel M Milne ◽  
Burcu Anar ◽  
Gareth Girling ◽  
Frank Schwach ◽  
...  
Keyword(s):  
Marker Genes ◽  
Plasmodium Chabaudi ◽  
Chronic Infections ◽  
Selectable Marker Genes ◽  
Erythrocyte Invasion ◽  
Infection Dynamics ◽  
Marker Free ◽  
Parasite Replication

The rodent parasite Plasmodium chabaudi is an important in vivo model of malaria. The ability to produce chronic infections makes it particularly useful for investigating the development of anti-Plasmodium immunity, as well as features associated with parasite virulence during both the acute and chronic phases of infection. P. chabaudi also undergoes asexual maturation (schizogony) and erythrocyte invasion in culture, so offers an experimentally-amenable in vivo to in vitro model for studying gene function and drug activity during parasite replication. To extend the usefulness of this model, we have further optimised transfection protocols and plasmids for P. chabaudi and generated stable, fluorescent lines that are free from drug-selectable marker genes. These mother-lines show the same infection dynamics as wild-type parasites throughout the lifecycle in mice and mosquitoes; furthermore, their virulence can be increased by serial blood passage and reset by mosquito transmission. We have also adapted the large-insert, linear PlasmoGEM vectors that have revolutionised the scale of experimental genetics in another rodent malaria parasite and used these to generate barcoded P. chabaudi gene-deletion and –tagging vectors for transfection in our fluorescent P. chabaudi mother-lines. This produces a tool-kit of P. chabaudi lines, vectors and transfection approaches that will be of broad utility to the research community.

scholarly journals The effect of salinity upon the boring activity and survival of Limnoria (Isopoda)

1961 ◽  
Vol 41 (3) ◽  
pp. 785-797 ◽  
Author(s):  
S. K. Eltringham
Keyword(s):  
No Reduction ◽  
Low Salinity ◽  
Early Stages ◽  
A Value ◽  
Constant Rate ◽  
Wood Boring

SUMMARYThe effect of salinity upon the wood-boring activity of Limnoria was investigated experimentally. Boring decreased linearly with salinity and ceased altogether below io%o. The limiting salinity varied inversely with the temperature, being 12%0 at 17-6 C and 15 %0 at 14-9 C (average temperatures). The boring activity was intensive in its early stages but after about 5 weeks fell to a lower constant rate.Survival experiments suggested that the low salinity was the direct cause of the reduced boring activity. The only lethal salinity found during the period of the experiments (65 days) was 6%0 which proved fatal in about 15-20 days. The next higher salinity tested was i2%0. No reduction in survival was found in concentrated salinities up to a value of 48 %0, the highest salinity examined.

Spherulitic crystal growth in the prodissoconch larval of Crassostrea virginica

1983 ◽  
Vol 41 ◽  
pp. 518-519
Author(s):  
George G. Cocks ◽  
Louis Leibovitz ◽  
DoSuk D. Lee
Keyword(s):  
Crystal Structure ◽  
Crassostrea Virginica ◽  
Crystal Orientation ◽  
Developmental Changes ◽  
Gastrula Stage ◽  
Orthorhombic Crystal ◽  
Orthorhombic Crystal Structure ◽  
Stages Of Growth ◽  
Early Stages ◽  
Initial Deposition

Our understanding of the structure and the formation of inorganic minerals in the bivalve shells has been considerably advanced by the use of electron microscope. However, very little is known about the ultrastructure of valves in the larval stage of the oysters. The present study examines the developmental changes which occur between the time of conception to the early stages of Dissoconch in the Crassostrea virginica(Gmelin), focusing on the initial deposition of inorganic crystals by the oysters.The spawning was induced by elevating the temperature of the seawater where the adult oysters were conditioned. The eggs and sperm were collected separately, then immediately mixed for the fertilizations to occur. Fertilized animals were kept in the incubator where various stages of development were stopped and observed. The detailed analysis of the early stages of growth showed that CaCO3 crystals(aragonite), with orthorhombic crystal structure, are deposited as early as gastrula stage(Figuresla-b). The next stage in development, the prodissoconch, revealed that the crystal orientation is in the form of spherulites.

Formation of Dislocation Channels in Neutron Irradiated Molybdenum

1972 ◽  
Vol 30 ◽  
pp. 672-673
Author(s):  
S. Mahajan
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Ambient Temperature ◽  
Room Temperature ◽  
Channel Formation ◽  
Early Stages ◽  
Transmission Electron ◽  
Three Stages ◽  
Two Stages ◽  
Polycrystalline Molybdenum

The evolution of dislocation channels in irradiated metals during deformation can be envisaged to occur in three stages: (i) formation of embryonic cluster free regions, (ii) growth of these regions into microscopically observable channels and (iii) termination of their growth due to the accumulation of dislocation damage. The first two stages are particularly intriguing, and we have attempted to follow the early stages of channel formation in polycrystalline molybdenum, irradiated to 5×1019 n. cm−2 (E > 1 Mev) at the reactor ambient temperature (∼ 60°C), using transmission electron microscopy. The irradiated samples were strained, at room temperature, up to the macroscopic yield point.Figure 1 illustrates the early stages of channel formation. The observations suggest that the cluster free regions, such as A, B and C, form in isolated packets, which could subsequently link-up to evolve a channel.

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