scholarly journals A Stochastic Intracellular Model of Anthrax Infection With Spore Germination Heterogeneity

2021 ◽  
Vol 12 ◽  
Author(s):  
Bevelynn Williams ◽  
Martín López-García ◽  
Joseph J. Gillard ◽  
Thomas R. Laws ◽  
Grant Lythe ◽  
...  
Keyword(s):  
Host Cell ◽  
Spore Germination ◽  
Germination Rate ◽  
Stochastic Modelling ◽  
Peritoneal Macrophages ◽  
Death Process ◽  
Significant Heterogeneity ◽  
Single Spore ◽  
Infection Dynamics

We present a stochastic mathematical model of the intracellular infection dynamics of Bacillus anthracis in macrophages. Following inhalation of B. anthracis spores, these are ingested by alveolar phagocytes. Ingested spores then begin to germinate and divide intracellularly. This can lead to the eventual death of the host cell and the extracellular release of bacterial progeny. Some macrophages successfully eliminate the intracellular bacteria and will recover. Here, a stochastic birth-and-death process with catastrophe is proposed, which includes the mechanism of spore germination and maturation of B. anthracis. The resulting model is used to explore the potential for heterogeneity in the spore germination rate, with the consideration of two extreme cases for the rate distribution: continuous Gaussian and discrete Bernoulli. We make use of approximate Bayesian computation to calibrate our model using experimental measurements from in vitro infection of murine peritoneal macrophages with spores of the Sterne 34F2 strain of B. anthracis. The calibrated stochastic model allows us to compute the probability of rupture, mean time to rupture, and rupture size distribution, of a macrophage that has been infected with one spore. We also obtain the mean spore and bacterial loads over time for a population of cells, each assumed to be initially infected with a single spore. Our results support the existence of significant heterogeneity in the germination rate, with a subset of spores expected to germinate much later than the majority. Furthermore, in agreement with experimental evidence, our results suggest that most of the spores taken up by macrophages are likely to be eliminated by the host cell, but a few germinated spores may survive phagocytosis and lead to the death of the infected cell. Finally, we discuss how this stochastic modelling approach, together with dose-response data, allows us to quantify and predict individual infection risk following exposure.

scholarly journals Nanoceria and bulk cerium oxide effects on the germination of asplenium adiantum-nigrum spores

2016 ◽  
Vol 25 (3) ◽  
pp. e067 ◽  
Author(s):  
Aranzazu Gomez-Garay ◽  
Beatriz Pintos ◽  
José Antonio Manzanera ◽  
Carmen Prada ◽  
Luisa Martin ◽  
...  
Keyword(s):  
Adverse Effect ◽  
Cerium Oxide ◽  
Spore Germination ◽  
Germination Rate ◽  
Membrane Damage ◽  
Membrane Integrity ◽  
Engineered Nanoparticles ◽  
Cellular Damage ◽  
Effect Concentration

Aim of study: The effect of cerium oxide engineered nanoparticles on the spore germination of the fern. Asplenium adiantum-nigrum.Area of study: France, Britanny Region, Finistére Department, Plougonvelin, in rocks near the sea.Material and methods: Asplenium spores were cultured in vitro on agar medium with Nano-CeO2 (less than 25 nm particle size) and bulk-CeO2. The addition of each nano- and bulk particles ranged from 0 to 3000 mg L-1. Observations on rhizoidal and prothallial cells during first stages of gametophyte development were made. The No-Observed-Adverse-Effect concentration (NOAEC) and Lowest-Observed-Adverse-Effect-Concentration (LOEC) values for spore germination rate data were analyzed. Main results: Germination was speeded up by 100 to 2000 mg L-1 nanoceria, while bulk cerium oxide had the same effect for 500 to 200 mg L-1 concentrations. Present results showed cellular damage in the protonema while rhizoid cells seemed not to be affected, as growth and membrane integrity remained.Research highlights: Both nanosized and bulk cerium oxide are toxic for the fern Asplenium adiantum-nigrum, although diverse toxicity patterns were shown for both materials. Diverse toxic effects have been observed: chloroplast membrane damage and lysis, cell wall and membrane disruption which leads to cell lysis; and alterations in morphology and development.Keywords: Nanoparticles; rhizoid; prothallus; chloroplast; fern.

scholarly journals Interaction of avirulent Leishmania species with rat peritoneal macrophages

1983 ◽  
Vol 78 (1) ◽  
pp. 21-26 ◽  
Author(s):  
Trina Bastardo ◽  
Lucila Arcay-de-Peraza ◽  
Félix Tejero
Keyword(s):  
Host Cell ◽  
Cutaneous Leishmaniasis ◽  
Leishmania Species ◽  
Peritoneal Macrophages ◽  
Peritoneal Exudate ◽  
Host Cells ◽  
In Vitro System ◽  
Leishmania Spp

An "in vitro" system has been developed for study of host cell-parasite interaction in visceral and cutaneous leishmaniasis. Avirulent promastigotes of L. brasiliensis and L. donovani, from strains originally isolated from human cases and mantained by serial culture in Davis' Medium were allowed to infect cultured macrophages from rat peritoneal exudate. Challenge of the macrophages by parasites took place in 199 medium, at 33ºC for L. brasiliensis and at 37ºC for L. donovani. Although the rat is resistant to infections by Leishmania spp., the promastigotes not only invaded the host cells, but transformed into amastigotes and later mutiplied, from 10 min after challenge to 24 hours later.

The development of Trypanosoma cruzi in macrophages in vitro. Interaction with lysosomes and host cell fate

Parasitology ◽  
1980 ◽  
Vol 80 (1) ◽  
pp. 139-145 ◽  
Author(s):  
Regina Milder ◽  
Judith Kloetzel
Keyword(s):  
Trypanosoma Cruzi ◽  
Host Cell ◽  
Cell Fate ◽  
Peritoneal Macrophages ◽  
Blue Dye ◽  
Cell Monolayers ◽  
Secondary Lysosomes ◽  
Electron Microscopical ◽  
In Vitro Interaction

SummaryThe interaction between mouse peritoneal macrophages and ‘Y’ strain Trypanosoma cruzi bloodstream forms was studied at optical and electron microscopical levels. The method of marking lysosomes with Thorotrast, either before or after infection of cell monolayers with parasites, revealed that secondary lysosomes fused with phagosomes shortly after trypanosome interiorization. In spite of this, 24 h later most parasites were no longer in a vacuole but lay free within the host cell cytoplasm, multiplying actively. At this time, and up to shortly before 96 h when parasites escaped to the external milieu, most parasitized cells were not lethally injured, as revealed by the Trypan blue dye-exclusion test. Only when parasites were released into the external medium was this situation reversed and infected macrophages took up the dye.

scholarly journals In Vitro Infection Dynamics of Japanese Encephalitis Virus in Established Porcine Cell Lines

Pathogens ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 1468
Author(s):  
Shakirat A. Adetunji ◽  
Dmitriy Smolensky ◽  
Dana N. Mitzel ◽  
Jeana L. Owens ◽  
Carol G. Chitko-McKown ◽  
...  
Keyword(s):  
Japanese Encephalitis Virus ◽  
Host Cell ◽  
Cell Lines ◽  
Japanese Encephalitis ◽  
Trypan Blue ◽  
Infectious Virus ◽  
Encephalitis Virus ◽  
Infection Dynamics ◽  
Porcine Cell

Japanese encephalitis virus (JEV) is a zoonotic mosquito-borne pathogen that regularly causes severe neurological disease in humans in Southeast Asia and the Western Pacific region. Pigs are one of the main amplifying hosts of JEV and play a central role in the virus transmission cycle. The objective of this study was to identify in vitro cell systems to investigate early effects of JEV infection including viral replication and host cell death. Here, we demonstrate the susceptibility of several porcine cell lines to the attenuated genotype III JEV strain SA14-14-2. Monolayers of porcine nasal turbinate (PT-K75), kidney (SK-RST), testis (ST), and monocyte-derived macrophage (CΔ2+) cells were infected with SA14-14-2 for up to five days at a multiplicity of infection (MOI) of 0.1. The hamster kidney cell line BHK-21, previously shown to be susceptible to SA14-14-2, was used as a positive control. Culture supernatants and cells were collected between 0 and 120 h post infection (hpi), and monolayers were observed for cytopathic effect (CPE) using brightfield microscopy. The number of infectious virus particles was quantified by plaque assay and cell viability was determined using trypan blue staining. An indirect immunofluorescence assay was used to detect the presence of JEV NS1 antigens in cells infected at 1 MOI. All four porcine cell lines demonstrated susceptibility to SA14-14-2 and produced infectious virus by 12 hpi. Virus titers peaked at 48 hpi in CΔ2+, BHK-21, and SK-RST cells, at 72 hpi in PT-K75, and at 120 hpi in ST cells. CPE was visible in infected CΔ2+ and BHK-21 cells, but not the other three cell lines. The proportion of viable cells, as measured by trypan blue exclusion, declined after 24 hpi in BHK-21 and 48 hpi in CΔ2+ cells, but did not substantially decline in SK-RST, PT-K75 or ST cells. At 48 hpi, JEV NS1 was detected in all infected cell lines by fluorescence microscopy. These findings demonstrate several porcine cell lines which have the potential to serve as useful research tools for investigating JEV infection dynamics and host cell mechanisms in a natural amplifying host species, such as pigs, in vitro.

scholarly journals Host lung environment limits Aspergillus fumigatus germination through a SskA-dependent signaling response

2021 ◽  
Author(s):  
Marina E. Kirkland ◽  
MacKenzie Stannard ◽  
Caitlin H. Kowalski ◽  
Dallas L. Mould ◽  
Alayna K. Caffrey-Carr ◽  
...  
Keyword(s):  
Aspergillus Fumigatus ◽  
Parental Strain ◽  
Mapk Pathway ◽  
Germination Rate ◽  
Significant Heterogeneity ◽  
Loss Of Function ◽  
Glucose Levels ◽  
Low Glucose

Aspergillus fumigatus isolates display significant heterogeneity in growth, virulence, pathology, and inflammatory potential in multiple murine models of invasive aspergillosis. Previous studies have linked the initial germination of a fungal isolate in the airways to the inflammatory and pathological potential; but the mechanism(s) regulating A. fumigatus germination in the airways are unresolved. To explore the genetic basis for divergent germination phenotypes, we utilized a serial passaging strategy in which we cultured a slow germinating strain (AF293) in a murine lung based medium for multiple generations. Through this serial passaging approach, a strain emerged with an increased germination rate that induces more inflammation than the parental strain (herein named Lung Homogenate Evolved (LH-EVOL)). We identified a potential loss of function allele of Afu5g08390 (sskA) in the LH-EVOL strain. The LH-EVOL strain had a decrease ability to induce the SakA-dependent stress pathway. In support of the whole genome variant analyses, sskA, sakA, or mpkC loss of function strains in the AF293 parental strain increased germination both in vitro and in vivo. Since the airway surface liquid of the lungs contains low glucose levels, the relationship of low glucose concentration on germination of these mutant AF293 strains was examined; interestingly, in low glucose conditions the sakA pathway mutants exhibited an enhanced germination rate. In conclusion, A. fumigatus germination in the airways is regulated by SskA through the SakA MAPK pathway and drives enhanced disease initiation and inflammation in the lungs.

Minimal contribution of cell-bound antibodies to the immunoscintigraphy of inflamed joints with 99mTc-anti-CD4 monoclonal antibodies

2002 ◽  
Vol 41 (03) ◽  
pp. 129-134 ◽  
Author(s):  
A. Wolski ◽  
E. Palombo-Kinne ◽  
F. Wolf ◽  
F. Emmrich ◽  
W. Becker ◽  
...  
Keyword(s):  
T Cells ◽  
Monoclonal Antibodies ◽  
Synovial Membrane ◽  
In Vitro Release ◽  
Peritoneal Macrophages ◽  
Lymphoid Organs ◽  
Whole Body ◽  
Free Form ◽  
Ankle Joints

Summary Aim: The cellular joint infiltrate in rheumatoid arthritis patients is rich in CD4-positive T-helper lymphocytes and macrophages, rendering anti-CD4 monoclonal antibodies (mAbs) suitable for specific immunoscintigraphy of human/ experimental arthritis. Following intravenous injection, however, mAbs are present both in the free form and bound to CD4-positive, circulating monocytes and T-cells. Thus, the present study aimed at analyzing the relative contribution of the free and the cell-bound component to the imaging of inflamed joints in experimental adjuvant arthritis (AA). Methods: AA rat peritoneal macrophages or lymph node T-cells were incubated in vitro with saturating amounts of 99mTc-anti-CD4 mAb (W3/25) and injected i.v. into rats with AA. Results: In vitro release of 99mTc-anti-CD4 mAb from the cells was limited (on average 1.57%/h for macrophages and 0.84%/h for T-cells). Following i.v. injection, whole body/joint scans and tissue measurements showed only negligible accumulation of radioactivity in inflamed ankle joints (tissue: 0.22 and 0.34% of the injected activity, respectively), whereas the radioactivity was concentrated in liver (tissue: 79% and 71%, respectively), kidney, and urinary bladder. Unlike macrophages, however, anti-CD4 mAb-coated T-cells significantly accumulated in lymphoid organs, the inflamed synovial membrane of the ankle joints, as well as in elbow and knee joints. Conclusion: While the overall contribution of cell-bound mAbs to the imaging of arthritic joints with anti-CD4 mAbs is minimal, differential accumulation of macrophages and T-cells in lymphoid organs and the inflamed synovial membrane indicates preferential migration patterns of these 2 cell populations in arthritic rats. Although only validated for 99mTc-anti-CD4 mAbs, extrapolation of the results to other anticellular mAbs with similar affinity for their antigen may be possible.

PENGEMBANGAN TEKNOLOGI SELEKSI IN VITRO BERULANG (REPEAT CYCLING–IN VITRO SELECTION) TOLERAN STRES KEKERINGAN UNTUK PERBAIKAN MUTU GENETIK DAN PRODUKSI TANAMAN KEDELAI BERMIKORIZA

2017 ◽  
Vol 1 (1) ◽  
pp. 74-84
Author(s):  
Ahmad Riduan ◽  
Rainiyati Rainiyati ◽  
Yulia Alia
Keyword(s):  
Arbuscular Mycorrhizae ◽  
In Vitro Selection ◽  
Soil Samples ◽  
Single Spore ◽  
Isolation And Characterization ◽  
Single Spore Culture ◽  
Spore Culture ◽  
Glomus Sp

Every plant rhizospheres in any ecosystem there are various living microorganisms including Arbuscular Mycorrhizae Fungi (AMF).  An isolation and characterization is required to investigate the species or type of the AMF. This research was aimed at studying the isolation and characterization of AMF sporulation in soybean rhizospheres in Jambi Province. The results of evaluation on soil samples before trapping showed that there are spores from three genus of AMF twelve types Glomus , two types Acaulospora and one type of Enthrophospora.  Following single spore culture in soybean rhizosphere, 5 spore types were obtained:  Glomus sp-1, Glomus sp-4, Glomus sp-7, Glomus sp-8 Glomus sp-10.

scholarly journals Intracellular localisation of Mycobacterium tuberculosis affects efficacy of the antibiotic pyrazinamide

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Pierre Santucci ◽  
Daniel J. Greenwood ◽  
Antony Fearns ◽  
Kai Chen ◽  
Haibo Jiang ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Host Cell ◽  
Combination Chemotherapy ◽  
In Vitro Activity ◽  
In Vivo Efficacy ◽  
Human Macrophages ◽  
Ion Microscopy ◽  
Intracellular Localisation

AbstractTo be effective, chemotherapy against tuberculosis (TB) must kill the intracellular population of the pathogen, Mycobacterium tuberculosis. However, how host cell microenvironments affect antibiotic accumulation and efficacy remains unclear. Here, we use correlative light, electron, and ion microscopy to investigate how various microenvironments within human macrophages affect the activity of pyrazinamide (PZA), a key antibiotic against TB. We show that PZA accumulates heterogeneously among individual bacteria in multiple host cell environments. Crucially, PZA accumulation and efficacy is maximal within acidified phagosomes. Bedaquiline, another antibiotic commonly used in combined TB therapy, enhances PZA accumulation via a host cell-mediated mechanism. Thus, intracellular localisation and specific microenvironments affect PZA accumulation and efficacy. Our results may explain the potent in vivo efficacy of PZA, compared to its modest in vitro activity, and its critical contribution to TB combination chemotherapy.

scholarly journals Revisiting Ehrlichia ruminantium Replication Cycle Using Proteomics: The Host and the Bacterium Perspectives

2021 ◽  
Vol 9 (6) ◽  
pp. 1144
Author(s):  
Isabel Marcelino ◽  
Philippe Holzmuller ◽  
Ana Coelho ◽  
Gabriel Mazzucchelli ◽  
Bernard Fernandez ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Host Cell ◽  
Cell Metabolism ◽  
Replication Cycle ◽  
Host Cells ◽  
Ehrlichia Ruminantium ◽  
Host Interaction ◽  
Infected Cells ◽  
Related Proteins

The Rickettsiales Ehrlichia ruminantium, the causal agent of the fatal tick-borne disease Heartwater, induces severe damage to the vascular endothelium in ruminants. Nevertheless, E. ruminantium-induced pathobiology remains largely unknown. Our work paves the way for understanding this phenomenon by using quantitative proteomic analyses (2D-DIGE-MS/MS, 1DE-nanoLC-MS/MS and biotin-nanoUPLC-MS/MS) of host bovine aorta endothelial cells (BAE) during the in vitro bacterium intracellular replication cycle. We detect 265 bacterial proteins (including virulence factors), at all time-points of the E. ruminantium replication cycle, highlighting a dynamic bacterium–host interaction. We show that E. ruminantium infection modulates the expression of 433 host proteins: 98 being over-expressed, 161 under-expressed, 140 detected only in infected BAE cells and 34 exclusively detected in non-infected cells. Cystoscape integrated data analysis shows that these proteins lead to major changes in host cell immune responses, host cell metabolism and vesicle trafficking, with a clear involvement of inflammation-related proteins in this process. Our findings led to the first model of E. ruminantium infection in host cells in vitro, and we highlight potential biomarkers of E. ruminantium infection in endothelial cells (such as ROCK1, TMEM16K, Albumin and PTPN1), which may be important to further combat Heartwater, namely by developing non-antibiotic-based strategies.

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