FURTHER STUDIES ON THE PHYSIOLOGY OF CLADOSPORIUM FULVUM CKE. AND RESISTANCE IN TOMATO

1964 ◽  
Vol 42 (10) ◽  
pp. 1365-1386 ◽  
Author(s):  
Ruth L. Lowther

Some host–parasite interactions of the C. fulvum – tomato leaf complex have been correlated with degrees of utilization in vitro by races of the pathogen of metabolites which have been shown to occur in different amounts in some tomato hosts which react differentially to them. Similarities and differences in the behavior of three pathogenic races were noted when the plants were grown in a number of amino nitrogen and sugar carbon sources. Similarities are interpreted as representing species characteristics; on the other hand, differences, including colony colors in glutamine and γ-aminobutyric acid, appear to be racial characteristics. Further evidence suggesting that certain host metabolites modify or condition the pathogenic expression was obtained from studies of the effect on pathogenicity of culture media differing in amino nitrogen content. From a comparison of the metabolites of host–pathogen complexes of differing reaction types, some insight was gained into probable nutritional requirements for a race 1 susceptible response. Conversely, where these differed in other reaction-type complexes, clues were obtained regarding possible reasons for resistance to this race.


2016 ◽  
pp. 39-44
Author(s):  
Ifra Tun Nur ◽  
Jannatun Tahera ◽  
Md Sakil Munna ◽  
M Majibur Rahman ◽  
Rashed Noor

With a previous observation of Escherichia coli growth cessation along with temperature variation within three different bacteriological culture media (nutrient agar, Luria-Bertani agar and minimal agar), current investigation further depicted on the possible growth dynamics of Escherichia coli (SUBE01) and Salmonella (SUBS01) growth and viability upon supplementation of different carbon sources (dextrose, sucrose, lactose, glycerol and tween 20) at 37°C under the aeration of 100 rpm. Viability of the tested bacterial species was assessed through the enumeration of the colony forming unit (cfu) appeared upon prescribed incubation for 12-24 hours on different agar plates consisting of the above mentioned carbon sources. Besides, to inspect the cellular phenotypic changes, morphological observations were conducted under the light microscope. Variations in bacterial growth (either growth acceleration or cessation) were further noticed through the spot tests on the agar plates. Considerable shortfalls in the culturable cells of E. coli and Salmonella spp. were noted in the minimal media separately consisting of sucrose, lactose, glycerol or tween 20 while an opposite impact of accelerated growth was noticed in the media supplied with dextrose. The data revealed a hierarchy of consequence of carbon sources as nutrient generators whereby the favourable bacterial growth and survival order of the carbon sources was estimated as dextrose > glycerol > lactose > tween 20 > sucrose.Bangladesh J Microbiol, Volume 32, Number 1-2,June-Dec 2015, pp 39-44



2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Sasha V. Siegel ◽  
Lia Chappell ◽  
Jessica B. Hostetler ◽  
Chanaki Amaratunga ◽  
Seila Suon ◽  
...  

Abstract Plasmodium vivax gene regulation remains difficult to study due to the lack of a robust in vitro culture method, low parasite densities in peripheral circulation and asynchronous parasite development. We adapted an RNA-seq protocol “DAFT-seq” to sequence the transcriptome of four P. vivax field isolates that were cultured for a short period ex vivo before using a density gradient for schizont enrichment. Transcription was detected from 78% of the PvP01 reference genome, despite being schizont-enriched samples. This extensive data was used to define thousands of 5′ and 3′ untranslated regions, some of which overlapped with neighbouring transcripts, and to improve the gene models of 352 genes, including identifying 20 novel gene transcripts. This dataset has also significantly increased the known amount of heterogeneity between P. vivax schizont transcriptomes from individual patients. The majority of genes found to be differentially expressed between the isolates lack Plasmodium falciparum homologs and are predicted to be involved in host-parasite interactions, with an enrichment in reticulocyte binding proteins, merozoite surface proteins and exported proteins with unknown function. An improved understanding of the diversity within P. vivax transcriptomes will be essential for the prioritisation of novel vaccine targets.





Parasitology ◽  
2009 ◽  
Vol 137 (3) ◽  
pp. 411-424 ◽  
Author(s):  
I. BARBER ◽  
J. P. SCHARSACK

SUMMARYPlerocercoids of the pseudophyllidean cestodeSchistocephalus solidusinfect the three-spined sticklebackGasterosteus aculeatus, with important consequences for the biology of host fish. Techniques for culturing the parasitein vitroand generating infective stages that can be used to infect sticklebacks experimentally have been developed, and the system is increasingly used as a laboratory model for investigating aspects of host-parasite interactions. Recent experimental laboratory studies have focused on the immune responses of hosts to infection, the consequences of infection for the growth and reproductive development of host fish and the effects of infection on host behaviour. Here we introduce the host and the parasite, review the major findings of these recent experimental infection studies and identify further aspects of host parasite interactions that might be investigated using the system.



2019 ◽  
Author(s):  
Matías Exequiel Rodríguez ◽  
Mariana Rizzi ◽  
Lucas D. Caeiro ◽  
Yamil E. Masip ◽  
Alina Perrone ◽  
...  

AbstractChaga’ disease, caused by the kinetoplastid parasite Trypanosoma cruzi, presents a variety of chronic clinical manifestations whose determinants are still unknown but probably influenced by the host-parasite interplay established during the first stages of the infection, when bloodstream circulating trypomastigotes disseminate to different organs and tissues. After leaving the blood, trypomastigotes must migrate through tissues to invade cells and establish a chronic infection. How this process occurs remains unexplored. Three-dimensional (3D) cultures are physiologically relevant because mimic the microarchitecture of tissues and provide an environment similar to the encountered in natural infections. In this work, we combined the 3D culture technology with host-pathogen interaction, by studying transmigration of trypomastigotes into 3D spheroids. T. cruzi strains with similar infection dynamics in 2D monolayer cultures but with different in vivo behavior (CL Brener, virulent; SylvioX10 no virulent) presented different infection rates in spheroids (CL Brener ∼40%, SylvioX10 <10%). Confocal microscopy images evidenced that trypomastigotes from CL Brener and other highly virulent strains presented a great ability to transmigrate inside 3D spheroids: as soon as 4 hours post infection parasites were found at 50 µm in depth inside the spheroids. CL Brener trypomastigotes were evenly distributed and systematically observed in the space between cells, suggesting a paracellular route of transmigration to deepen into the spheroids. On the other hand, poor virulent strains presented a weak migratory capacity and remained in the external layers of spheroids (<10µm) with a patch-like distribution pattern. The invasiveness -understood as the ability to transmigrate deep into spheroids- was not a transferable feature between strains, neither by soluble or secreted factors nor by co-cultivation of trypomastigotes from invasive and non-invasive strains. We also studied the transmigration of recent T. cruzi isolates from children that were born congenitally infected, which showed a high migrant phenotype while an isolate form an infected mother (that never transmitted the infection to any of her 3 children) was significantly less migratory. Altogether, our results demonstrate that in a 3D microenvironment each strain presents a characteristic migration pattern and distribution of parasites in the spheroids that can be associated to their in vivo behavior. Certainly, the findings presented here could not have been studied with traditional 2D monolayer cultures.Author SummaryTrypanosoma cruzi is the protozoan parasite that causes Chaga’ disease, also known as American trypanosomiasis. Experimental models of the infection evidence that different strains of the parasite present different virulence in the host, which cannot be always reproduced in 2D monolayer cultures. Three dimensional (3D) cultures can be useful models to study complex host-parasite interactions because they mimic in vitro the microarchitecture of tissues and provide an environment similar to the encountered in natural infections. In particular, spheroids are small 3D aggregates of cells that interact with each other and with the extracellular matrix that they secrete resembling the original microenvironment both functionally and structurally. Spheroids have rarely been employed to explore infectious diseases and host-parasite interactions. In this work we studied how bloodstream trypomastigotes transmigrate through 3D spheroids mimicking the picture encountered by parasites in tissues soon after leaving circulation. We showed that the behavior of T. cruzi trypomastigotes in 3D cultures reflects their in vivo virulence: virulent strains transmigrate deeply into spheroids while non-virulent strains remain in the external layers of spheroids. Besides, this work demonstrates the usefulness of 3D cultures as an accurate in vitro model for the study of host-pathogen interactions that could not be addressed with conventional monolayer cultures.



2009 ◽  
Vol 9 (1) ◽  
pp. 280 ◽  
Author(s):  
Bernhard Guggenheim ◽  
Rudolf Gmür ◽  
Johnah C Galicia ◽  
Panagiota G Stathopoulou ◽  
Manjunatha R Benakanakere ◽  
...  


2002 ◽  
Vol 15 (3) ◽  
pp. 327-328 ◽  
Author(s):  
Govinda S. Visvesvara ◽  
Lynne S. Garcia

SUMMARY The in vitro culture of protozoan parasites involves highly complex procedures, which are subject to many variables. These parasites have very complex life cycles and, depending on the life cycle stage, may require different culture parameters. However, in vitro cultivation is important for many reasons, some of which include: diagnosis, antigen and antibody production, assessment of parasite immune modulating capabilities, drug screening, improvements in chemotherapy, differentiation of clinical isolates, determination of strain differences, vaccine production, development of attenuated strains, and the continued supply of viable organisms for studying host-parasite interactions.



2021 ◽  
Author(s):  
Estefanía Calvo Alvarez ◽  
Aline Crouzols ◽  
Brice Rotureau

The African trypanosome flagellum is essential in multiple aspects of the parasite development. In the mammalian infective form of this protist, FLAgellar Member 8 (FLAM8) is a large protein distributed along the entire flagellum that is suspected to be involved in host-parasite interactions. Analyses of knockdown and knockout trypanosomes demonstrated that FLAM8 is not essential in vitro for survival, growth, motility and slender to stumpy differentiation. Functional investigations in experimental infections showed that FLAM8 -deprived trypanosomes are able to establish and maintain the infection in the blood circulation, and to differentiate into transmissible stumpy forms. However, bioluminescence imaging revealed that FLAM8 -null parasites exhibit an impaired dissemination in the extravascular compartment, especially in the skin, that is partially restored by the addition of a single rescue copy of FLAM8 . To our knowledge, FLAM8 is the first example of a flagellar protein that modulates T. brucei parasite distribution in the host tissues, contributing to the maintenance of extravascular parasite populations in mammalian anatomical niches.



2021 ◽  
Author(s):  
Kaiyan Zhang ◽  
Yanyou Wu ◽  
Yue Su ◽  
Haitao Li

Abstract BackgroundPlantlets grown in vitro with a mixed nitrogen source utilize sucrose and CO2 as carbon sources for growth. However, it is very difficult to obtain the correct proportion of assimilated nitrate, ammonium, sucrose and CO2 for plantlets. Consequently, the NH4+/NO3- use efficiency for carbon fixation derived from the assimilation of sucrose/CO2 is still unclear for plantlets. ResultsThe bidirectional stable nitrogen isotope tracer technique was employed to quantify the proportions of nitrate and ammonium utilized at different NH4+/ NO3- ratios, and the proportions of sucrose and CO2 assimilation were quantified by the foliar δ13C values of plantlets. There was an obvious difference in the assimilation of nitrate and ammonium under different NH4+/NO3- ratios for Brassica napus (Bn) plantlets. Increasing the supply of nitrate contributed to enhancing the assimilation of nitrate and ammonium simultaneously. The nitrate utilization coefficients of the Bn plantlets had no distinct change with increasing nitrate concentration, while the ammonium utilization coefficients of the Bn plantlets increased obviously with increasing nitrate concentration. The proportion of sucrose/CO2 assimilation depended on the NH4+/NO3- ratios of the Bn plantlets. Both nitrate and ammonium assimilation were independent of sucrose/CO2 assimilation. Based on the proportion of CO2, sucrose, nitrate and ammonium utilization, the nitrate/ammonium use efficiency (as indicated by the C/N ratio) for carbon fixation derived from the assimilation of sucrose/CO2 can be quantified for Bn plantlets.ConclusionsQuantifying the utilization proportions of nitrate and ammonium can reveal the difference in nitrate and ammonium utilization among plantlets at different NH4+/NO3- ratios. Foliar δ13C value in combination of the foliar δ15N value of plantlets can be used to quantify the nitrate/ammonium use efficiency for the carbon fixation derived from the assimilation of sucrose/CO2, which contributes to knowing the coupling process of carbon and nitrogen in plantlets and provides an alternate way to optimize the supply of inorganic nitrogen in culture media.



Parasitology ◽  
2010 ◽  
Vol 137 (3) ◽  
pp. 425-438 ◽  
Author(s):  
D. HOOLE ◽  
V. CARTER ◽  
S. DUFOUR

SUMMARYSince its use as a model to study metazoan parasite culture and in vitro development, the plerocercoid of the tapeworm, Ligula intestinalis, has served as a useful scientific tool to study a range of biological factors, particularly within its fish intermediate host. From the extensive long-term ecological studies on the interactions between the parasite and cyprinid hosts, to the recent advances made using molecular technology on parasite diversity and speciation, studies on the parasite have, over the last 60 years, led to significant advances in knowledge on host-parasite interactions. The parasite has served as a useful model to study pollution, immunology and parasite ecology and genetics, as well has being the archetypal endocrine disruptor.



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