scholarly journals Une étude in vitro du cycle de vie de Cowdria ruminantium

1993 ◽  
Vol 46 (1-2) ◽  
pp. 247-247
Author(s):  
L. Prozesky ◽  
A. Hart ◽  
M.S. Brett
Keyword(s):  
Post Inoculation ◽  
Cowdria Ruminantium ◽  
Cycle De Vie

Le cycle de vie de Cowdria ruminantium a été étudié dans des cellules SBE 189 par microscopie classique et électronique. Des cultures ont été infectées avec un inoculum synchronisé et fixées et préparées entre 15 min et 111 h post-inoculation (PI). Après 12 h, de grands corps réticulaires seuls ou en petits groupes ont été identifiés dans des vacuoles intracytoplasmatiques entourées de membranes. Ils se développaient graduellement dans des corps réticulaires plus petits avec une structure interne plus granuleuse. De 66 à 75 h PI, il y avait une augmentation importante de la taille des colonies. La plupart des colonies contenaient des corps réticulaires, bien que quelques corps intermédiaires et opaques aux électrons aient été visibles. Des corps réticulaires solitaires extracellulaires avec une couche ressemblant au peptidoglycan ont été observés 84 h PI. Après 90 h, des corps intermédiaires et opaques aux électrons fussent présents en abondance et cela coïncidait avec la lyse des cellules de culture. Le cycle de développement de Cowdria ruminantium durait donc environ 4 jours, dans cette étude.

scholarly journals Topical Application of Double-Stranded RNA Targeting 2b and CP Genes of Cucumber mosaic virus Protects Plants against Local and Systemic Viral Infection

Plants ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 963
Author(s):  
Maria C. Holeva ◽  
Athanasios Sklavounos ◽  
Rajendran Rajeswaran ◽  
Mikhail M. Pooggin ◽  
Andreas E. Voloudakis
Keyword(s):  
Cucumber Mosaic Virus ◽  
Mosaic Virus ◽  
Topical Application ◽  
Plant Virus ◽  
Plant Protection ◽  
Post Inoculation ◽  
Tobacco Plants ◽  
Double Stranded Rna

Cucumber mosaic virus (CMV) is a destructive plant virus with worldwide distribution and the broadest host range of any known plant virus, as well as a model plant virus for understanding plant–virus interactions. Since the discovery of RNA interference (RNAi) as a major antiviral defense, RNAi-based technologies have been developed for plant protection against viral diseases. In plants and animals, a key trigger of RNAi is double-stranded RNA (dsRNA) processed by Dicer and Dicer-like (DCL) family proteins in small interfering RNAs (siRNAs). In the present study, dsRNAs for coat protein (CP) and 2b genes of CMV were produced in vitro and in vivo and applied onto tobacco plants representing a systemic solanaceous host as well as on a local host plant Chenopodium quinoa. Both dsRNA treatments protected plants from local and systemic infection with CMV, but not against infection with unrelated viruses, confirming sequence specificity of antiviral RNAi. Antiviral RNAi was effective when dsRNAs were applied simultaneously with or four days prior to CMV inoculation, but not four days post inoculation. In vivo-produced dsRNAs were more effective than the in vitro-produced; in treatments with in vivo dsRNAs, dsRNA-CP was more effective than dsRNA-2b, while the effects were opposite with in vitro dsRNAs. Illumina sequencing of small RNAs from in vivo dsRNA-CP treated and non-treated tobacco plants revealed that interference with CMV infection in systemic leaves coincides with strongly reduced accumulation of virus-derived 21- and 22-nucleotide (nt) siRNAs, likely generated by tobacco DCL4 and DCL2, respectively. While the 21-nt class of viral siRNAs was predominant in non-treated plants, 21-nt and 22-nt classes accumulated at almost equal (but low) levels in dsRNA treated plants, suggesting that dsRNA treatment may boost DCL2 activity. Taken together, our findings confirm the efficacy of topical application of dsRNA for plant protection against viruses and shed more light on the mechanism of antiviral RNAi.

scholarly journals Effect of Scrapie Prion Infection in Ovine Bone Marrow-Derived Mesenchymal Stem Cells and Ovine Mesenchymal Stem Cell-Derived Neurons

Animals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 1137
Author(s):  
Laura García-Mendívil ◽  
Diego R. Mediano ◽  
Adelaida Hernaiz ◽  
David Sanz-Rubio ◽  
Francisco J. Vázquez ◽  
...  
Keyword(s):  
Stem Cells ◽  
Bone Marrow ◽  
Mesenchymal Stem Cells ◽  
Cellular Prion Protein ◽  
Transmissible Spongiform Encephalopathies ◽  
Post Inoculation ◽  
Spongiform Encephalopathies ◽  
Prion Infection ◽  
Over Time

Scrapie is a prion disease affecting sheep and goats and it is considered a prototype of transmissible spongiform encephalopathies (TSEs). Mesenchymal stem cells (MSCs) have been proposed as candidates for developing in vitro models of prion diseases. Murine MSCs are able to propagate prions after previous mouse-adaptation of prion strains and, although ovine MSCs express the cellular prion protein (PrPC), their susceptibility to prion infection has never been investigated. Here, we analyze the potential of ovine bone marrow-derived MSCs (oBM-MSCs), in growth and neurogenic conditions, to be infected by natural scrapie and propagate prion particles (PrPSc) in vitro, as well as the effect of this infection on cell viability and proliferation. Cultures were kept for 48–72 h in contact with homogenates of central nervous system (CNS) samples from scrapie or control sheep. In growth conditions, oBM-MSCs initially maintained detectable levels of PrPSc post-inoculation, as determined by Western blotting and ELISA. However, the PrPSc signal weakened and was lost over time. oBM-MSCs infected with scrapie displayed lower cell doubling and higher doubling times than those infected with control inocula. On the other hand, in neurogenic conditions, oBM-MSCs not only maintained detectable levels of PrPSc post-inoculation, as determined by ELISA, but this PrPSc signal also increased progressively over time. Finally, inoculation with CNS extracts seems to induce the proliferation of oBM-MSCs in both growth and neurogenic conditions. Our results suggest that oBM-MSCs respond to prion infection by decreasing their proliferation capacity and thus might not be permissive to prion replication, whereas ovine MSC-derived neuron-like cells seem to maintain and replicate PrPSc.

scholarly journals A Thioredoxin Domain-Containing Protein Interacts with Pepino mosaic virus Triple Gene Block Protein 1

2018 ◽  
Vol 19 (12) ◽  
pp. 3747
Author(s):  
Matthaios Mathioudakis ◽  
Souheyla Khechmar ◽  
Carolyn Owen ◽  
Vicente Medina ◽  
Karima Ben Mansour ◽  
...  
Keyword(s):  
Mosaic Virus ◽  
Triple Gene Block ◽  
Polyclonal Antiserum ◽  
Post Inoculation ◽  
Mrna Levels ◽  
In Planta ◽  
Pepino Mosaic Virus ◽  
Gene Block ◽  
Triple Gene Block Protein

Pepino mosaic virus (PepMV) is a mechanically-transmitted tomato pathogen of importance worldwide. Interactions between the PepMV coat protein and triple gene block protein (TGBp1) with the host heat shock cognate protein 70 and catalase 1 (CAT1), respectively, have been previously reported by our lab. In this study, a novel tomato interactor (SlTXND9) was shown to bind the PepMV TGBp1 in yeast-two-hybrid screening, in vitro pull-down and bimolecular fluorescent complementation (BiFC) assays. SlTXND9 possesses part of the conserved thioredoxin (TRX) active site sequence (W__PC vs. WCXPC), and TXND9 orthologues cluster within the TRX phylogenetic superfamily closest to phosducin-like protein-3. In PepMV-infected and healthy Nicotiana benthamiana plants, NbTXND9 mRNA levels were comparable, and expression levels remained stable in both local and systemic leaves for 10 days post inoculation (dpi), as was also the case for catalase 1 (CAT1). To localize the TXND9 in plant cells, a polyclonal antiserum was produced. Purified α-SlTXND9 immunoglobulin (IgG) consistently detected a set of three protein bands in the range of 27–35 kDa, in the 1000 and 30,000 g pellets, and the soluble fraction of extracts of healthy and PepMV-infected N. benthamiana leaves, but not in the cell wall. These bands likely consist of the homologous protein NbTXND9 and its post-translationally modified derivatives. On electron microscopy, immuno-gold labelling of ultrathin sections of PepMV-infected N. benthamiana leaves using α-SlTXND9 IgG revealed particle accumulation close to plasmodesmata, suggesting a role in virus movement. Taken together, this study highlights a novel tomato-PepMV protein interaction and provides data on its localization in planta. Currently, studies focusing on the biological function of this interaction during PepMV infection are in progress.

scholarly journals EVALUATION OF ANTIBACTERIAL RESISTANCE OF BIOFILM FORMS OF AVIAN SALMONELLA GALLINARUM TO FLUOROQUINOLONES

2018 ◽  
Author(s):  
Kumar Kamashi ◽  
Mr. Honnegowda ◽  
Mayanna Asha ◽  
Chandrakala Ms.
Keyword(s):  
Pathogenic Bacteria ◽  
Inhibitory Concentration ◽  
Minimum Bactericidal Concentration ◽  
Bacterial Biofilms ◽  
Dilution Method ◽  
Post Inoculation ◽  
Antibacterial Resistance ◽  
Salmonella Gallinarum ◽  
Broth Dilution

Antimicrobial resistance is a growing concern worldwide. The indiscriminate use of antibiotics for a period of time has led to the emergence of antibiotic resistance in pathogenic bacteria. The present study was designed to evaluate the antibacterial efficacy of fluoroquinolone drugs, ciprofloxacin, enrofloxacin, moxifloxacin, sparfloxacin, norfloxacin, pefloxacin and ofloxacin against avian Salmonella gallinarum bacterial biofilms. The study parameters, minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC) and biofilm elimination concentration (BEC) were determined on days 1, 3, 7, 10, 14 and 20 post inoculation for the planktonic (free) and biofilm cells of S. gallinarum by macro broth dilution method. The MIC and MBC values determined on days 1, 3, 7, 10, 14 and 20 for each of the fluoroquinolone drugs against the planktonic and biofilm forms of avian S. gallinarum were found to be non-significant. BEC values determined against the biofilm forms of S. gallinarum during the study period were found to be non-significant among the tested fluoroquinolones. The results of the present study demonstrated that fluoroquinolone drugs were effective in vitro against both the planktonic and biofilm forms of avian S. gallinarum.

scholarly journals Expression d’interleukine 6 après infection par Cowdria ruminantium de cellules endothéliales de cerveau bovin

1993 ◽  
Vol 46 (1-2) ◽  
pp. 195-195
Author(s):  
Albert Bensaïd ◽  
S. Bourdoulous ◽  
D. Lerhun ◽  
D. Calvez ◽  
L. Droogman ◽  
...  
Keyword(s):  
Cowdria Ruminantium ◽  
Phase Aiguë ◽  
Cellules T

Les interleukines sont des médiateurs protéiques solubles qui peuvent déclencher une activation cellulaire. D’abord impliquée dans l’activation des cellules T dans la production d’immunoglobulines par les cellules B, l’interleukine 6 (IL6) provoque aussi l’induction de protéines de la phase aiguë par les hépatocytes. Ainsi, l’IL6 est impliquée dans les processus inflammatoires qui sont en grande partie responsables de la pathogénie de la cowdriose. Originellement produit par des macrophages et des cellules endothéliales activées, l’IL6 agit comme un stimulant de la réponse immunitaire. Néanmoins, quand elle est produite constamment et en grandes quantités, l’IL6 provoque des réactions inflammatoires non contrôlées. Afin de tester si l’IL6 est impliquée dans la cowdriose, une culture primaire de cellules endothéliales de cerveau bovin (BBEC) a été infectée in vitro par C. ruminantium. Les cellules infectées ont été récoltées tous les jours et ce jusqu’au sixième jour où toutes les cellules sont lysées. La même expérience a été effectuée sur des BBEC qui ont été simultanément infectées et traitées avec de l’INFγ. De l’ARN a été purifié à partir de ces cellules et après électrophorèse sur gel d’agarose transféré sur un filtre de nylon. Ce filtre a été sondé avec un ADNc radiomarqué codant pour l’IL6 bovine. Des signaux à 1 kb ont été détectés seulement sur les ARN de cellules après le quatrième jour de l’infection, que celles-ci aient été traitées ou non par l’INFγ. Tous les autres échantillons, incluant l’ARN de cellules qui n’ont pas été infectées mais traitées à l’INFγ, se sont révélés négatifs pour l’expression d’IL6. Ainsi, après infection par C. ruminantium, l’expression d’IL6 est induite peu avant que l’effet cytopathogène n’apparaisse. A l’heure actuelle, des surnageants de milieu de culture de ces cellules sont testés pour leur capacité à induire des réponses prolifératives des cellules T.

scholarly journals Transcriptomic analysis of resistant and susceptible responses in a new model root-knot nematode infection system using Solanum torvum and Meloidogyne arenaria

2021 ◽  
Author(s):  
Kazuki Sato ◽  
Taketo Uehara ◽  
Julia Holbein ◽  
Yuko Sasaki-Sekimoto ◽  
Pamela Gan ◽  
...  
Keyword(s):  
Nematode Infection ◽  
Plant Genome ◽  
Root Tip ◽  
Post Inoculation ◽  
Sequencing Analysis ◽  
Class Iii ◽  
Root Knot Nematode ◽  
Cell Wall Modification ◽  
Solanum Torvum

ABSTRACTRoot-knot nematodes (RKNs) are among the most devastating pests in agriculture. Solanum torvum Sw. (turkey berry) has been used as a rootstock for eggplant (aubergine) cultivation because of its resistance to RKNs, including Meloidogyne incognita and M. arenaria. We previously found that a pathotype of M. arenaria, A2-J, is able to infect and propagate in S. torvum. In vitro infection assays showed that S. torvum induces the accumulation of brown pigments during avirulent pathotype A2-O infection, but not during virulent A2-J infection. This experimental system is advantageous because resistant and susceptible responses can be distinguished within a few days, and because a single plant genome can yield information about both resistant and susceptible responses. Comparative RNA-sequencing analysis of S. torvum inoculated with A2-J and A2-O at early stages of infection was used to parse the specific resistance and susceptible responses. Infection with A2-J did not induce statistically significant changes in gene expression within one day post-inoculation (DPI), but afterward, A2-J specifically induced the expression of chalcone synthase, spermidine synthase, and genes related to cell wall modification and transmembrane transport. Infection with A2-O rapidly induced the expression of genes encoding class III peroxidases, sesquiterpene synthases, and fatty acid desaturases at 1 DPI, followed by genes involved in defense, hormone signaling, and the biosynthesis of lignin at 3 DPI. Both isolates induced the expression of suberin biosynthetic genes, which may be triggered by wounding during nematode infection. Histochemical analysis revealed that A2-O, but not A2-J, induced lignin accumulation at the root tip, suggesting that physical reinforcement of cell walls with lignin is an important defense response against nematodes. The S. torvum-RKN system can provide a molecular basis for understanding plant-nematode interactions.

scholarly journals Le développement d’anticorps contre Cowdria ruminantium chez la souris et leur rôle dans la cowdriose

1993 ◽  
Vol 46 (1-2) ◽  
pp. 197-201
Author(s):  
B. Byrom ◽  
Suman M. Mahan ◽  
Anthony F. Barbet
Keyword(s):  
Cowdria Ruminantium

Les réponses immunitaires contre Cowdria ruminantium ont été étudiées en utilisant des souris DBA/2 et Balb/c comme modèle. Les deux souches de souris ont été inoculées avec 1, 10 ou 100 DL50 de C. ruminantium (stock Crystal Springs). Des anticorps contre C. ruminantium ont commencé à se développer dans la deuxième semaine après l'inoculation et le titre d'anticorps dépendait de la dose de C. ruminantium inoculée. Le rôle possible des anticorps sur la maladie a été recherché au moyen des tests de neutralisation in vitro, utilisant des sérums de souris et de bovins. Les résultats ont montré que les sérums hyperimmuns des souris DBA/2 et Balb/c étaient capables de neutraliser l'infection in vitro, celui des souris DBA/2 montrant l'effet neutralisant le plus fort. Deux sérums de bovins, l'un d'un animal infecté au laboratoire et l'autre provenant d'un mélange de sérums de deux animaux infectés naturellement, ont également montré un effet neutralisant.

scholarly journals Classical BSE prions emerge from asymptomatic pigs challenged with atypical/Nor98 scrapie

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Belén Marín ◽  
Alicia Otero ◽  
Séverine Lugan ◽  
Juan Carlos Espinosa ◽  
Alba Marín-Moreno ◽  
...  
Keyword(s):  
Protein Misfolding ◽  
Clinical Signs ◽  
Transmissible Spongiform Encephalopathies ◽  
Spongiform Encephalopathy ◽  
Post Inoculation ◽  
Atypical Scrapie ◽  
Wasting Disease ◽  
Spongiform Encephalopathies ◽  
Robust Transmission

AbstractPigs are susceptible to infection with the classical bovine spongiform encephalopathy (C-BSE) agent following experimental inoculation, and PrPSc accumulation was detected in porcine tissues after the inoculation of certain scrapie and chronic wasting disease isolates. However, a robust transmission barrier has been described in this species and, although they were exposed to C-BSE agent in many European countries, no cases of natural transmissible spongiform encephalopathies (TSE) infections have been reported in pigs. Transmission of atypical scrapie to bovinized mice resulted in the emergence of C-BSE prions. Here, we conducted a study to determine if pigs are susceptible to atypical scrapie. To this end, 12, 8–9-month-old minipigs were intracerebrally inoculated with two atypical scrapie sources. Animals were euthanized between 22- and 72-months post inoculation without clinical signs of TSE. All pigs tested negative for PrPSc accumulation by enzyme immunoassay, immunohistochemistry, western blotting and bioassay in porcine PrP mice. Surprisingly, in vitro protein misfolding cyclic amplification demonstrated the presence of C-BSE prions in different brain areas from seven pigs inoculated with both atypical scrapie isolates. Our results suggest that pigs exposed to atypical scrapie prions could become a reservoir for C-BSE and corroborate that C-BSE prions emerge during interspecies passage of atypical scrapie.

scholarly journals Isolation and Identification of Fusarium spp., the Causal Agents of Onion (Allium cepa) Basal Rot in Northeastern Israel

Biology ◽  
2020 ◽  
Vol 9 (4) ◽  
pp. 69
Author(s):  
Ben Kalman ◽  
Dekel Abraham ◽  
Shaul Graph ◽  
Rafael Perl-Treves ◽  
Yael Meller Harel ◽  
...  
Keyword(s):  
Allium Cepa ◽  
Fusarium Species ◽  
Germination Rate ◽  
Post Inoculation ◽  
Fusarium Spp ◽  
Isolation And Identification ◽  
Preventive Program ◽  
Onion Bulbs ◽  
Basal Rot

Over the past decade, there have been accumulating reports from farmers and field extension personnel on the increasing incidence and spread of onion (Allium cepa) bulb basal rot in northern Israel. The disease is caused mainly by Fusarium species. Rotting onion bulbs were sampled from fields in the Golan Heights in northeastern Israel during the summers of 2017 and 2018. Tissue from the sampled onion bulbs was used for the isolation and identification of the infecting fungal species using colony and microscopic morphology characterization. Final confirmation of the pathogens was performed with PCR amplification and sequencing using fungi-specific and Fusarium species-specific primers. Four Fusarium spp. isolates were identified in onion bulbs samples collected from the contaminated field: F. proliferatum, F. oxysporum f. sp. cepae, and two species less familiar as causative agents of this disease, F. acutatum and F. anthophilium. Phylogenetic analysis revealed that these species subdivided into two populations, a northern group isolated from white (Riverside cv.) onion bulbs, and a southern group isolated from red (565/505 cv.) bulbs. Pathogenicity tests conducted with seedlings and bulbs under moist conditions proved that all species could cause the disease symptoms, but with different degrees of virulence. Inoculating seeds with spore suspensions of the four species, in vitro, significantly reduced seedlings’ germination rate, hypocotyl elongation, and fresh biomass. Mature onion bulbs infected with the fungal isolates produced typical rot symptoms 14 days post-inoculation, and the fungus from each infected bulb was re-isolated and identified to satisfy Koch’s postulates. The onion bulb assay also reflected the degree of sensitivity of different onion cultivars to the disease. This work is the first confirmed report of the direct and primary cause of Fusarium onion basal rot disease in northeastern Israel. These findings are a necessary step towards uncovering the mycoflora of the diseased onion plants and developing a preventive program that would reduce the disease damage.

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