Electron microscopy of susceptible and resistant near-isogenic (sr6/Sr6) lines of wheat infected by Puccinia graminis tritici. II. Expression of incompatibility in mesophyll and epidermal cells and the effect of temperature on host–parasite interactions in these cells

1979 ◽  
Vol 57 (23) ◽  
pp. 2617-2625 ◽  
Author(s):  
D. E. Harder ◽  
R. Rohringer ◽  
D. J. Samborski ◽  
S. R. Rimmer ◽  
W. K. Kim ◽  
...  
Keyword(s):  
Resistance Gene ◽  
Epidermal Cells ◽  
Host Cells ◽  
Effect Of Temperature ◽  
Temperature Sensitive ◽  
Structural Abnormality ◽  
Mesophyll Cells ◽  
Backcross Line ◽  
Chinese Spring Wheat ◽  
Host Parasite

Primary leaves of near-isogenic lines of Chinese Spring wheat, either with or without the temperature-sensitive resistance gene Sr6, were inoculated with an avirulent race of stem rust, maintained at 19, 26, or 28 °C, and harvested 1–4 days after inoculation. The infected tissues were examined with an electron microscope to determine the effects of these temperatures on the expression of the Sr6 gene. At 26 °C in the Sr6 line about one-half of the haustoria in mesophyll cells were disorganized or collapsed. None of the haustoria in epidermal cells showed any structural abnormality. In the susceptible (sr6) line, most haustoria were structurally normal at 26 °C whether they were in mesophyll or epidermal cells. There were no signs of disorganization or necrosis of infected host cells of either (Sr6 or sr6) line at 26 °C. At 28 °C in both lines, all haustoria in mesophyll cells were necrotic or collapsed, but those in epidermal cells were not. No host cell necrosis was observed in genotypically resistant leaves. At 19 °C, most haustoria and invaded mesophyll cells in the Sr6 line were necrotic. In the invaded epidermal cells neither haustoria nor host protoplasts were necrotic. In contrast, in a backcross line of Marquis wheat containing resistance gene Sr5 and infected with an avirulent race, both invaded mesophyll and epidermal cells were necrotic.

THE PHYSIOLOGY OF HOST–PARASITE RELATIONS: XVIII. DISTRIBUTION OF TRITIUM-LABELLED CYTIDINE, URIDINE, AND LEUCINE IN WHEAT LEAVES INFECTED WITH THE STEM RUST FUNGUS

1967 ◽  
Vol 45 (5) ◽  
pp. 555-563 ◽  
Author(s):  
P. K. Bhattacharya ◽  
Michael Shaw
Keyword(s):  
Stem Rust ◽  
Rust Fungus ◽  
Host Cells ◽  
Fungal Mycelium ◽  
Puccinia Graminis ◽  
Mesophyll Cells ◽  
Wheat Leaves ◽  
Host Parasite

Wheat leaves were detached 6 days after inoculation with the stem rust fungus (Puccinia graminis var. tritici Erikss. and Henn.) and fed with tritiated leucine, cytidine, uridine, or thymidine. Mesophyll cells in infected zones incorporated more leucine into protein and more cytidine and uridine into RNA than did cells in adjacent uninfected tissue. Leucine, cytidine, and uridine were also heavily incorporated by fungal mycelium and developing uredospores. Grain counts over host nuclei in the infected zone were two to three-fold of those over nuclei in adjacent uninfected zones. There was no detectable incorporation of thymidinemethyl-3H into either the fungus or the host cells. The results are discussed.

A histological study of interactions between avirulent races of stem rust and wheat containing resistance genes Sr5, Sr6, Sr8, or Sr22

1979 ◽  
Vol 57 (4) ◽  
pp. 324-331 ◽  
Author(s):  
R. Rohringer ◽  
W. K. Kim ◽  
D. J. Samborski
Keyword(s):  
Resistance Genes ◽  
Stem Rust ◽  
Chinese Spring ◽  
Histological Study ◽  
Fungal Growth ◽  
Triticum Aestivum L ◽  
Epidermal Cells ◽  
Host Cells ◽  
Colony Development ◽  
Mesophyll Cells

Primary leaves of wheat (Triticum aestivum L.) with and without resistance genes Sr5, Sr6, Sr8, or Sr22 were inoculated with avirulent races of stem rust (Puccinia graminis Pers. f. sp. tritici Eriks. & E. Henn.) and examined by fluorescence microscopy. In leaves containing the Sr5 gene for resistance, both epidermal and mesophyll cells fluoresced when interacting with the fungus, indicating incompatibility. In leaves containing the Sr6 gene, interacting epidermal cells did not fluoresce and incompatibility was expressed only in mesophyll cells.When the effect of the Sr5 gene was studied in leaves with different genetic backgrounds, it was found that most colonies developed only one or two haustorial mother cells in leaves containing this gene in Prelude, Marquis, or Reliance backgrounds, when examined up to 72 h after incubation. Conversely, in leaves with the Chinese Spring background, one-third of the colonies continued to grow and they produced macroscopically visible lesions. Our observations indicated that the Chinese Spring genotype partially altered the expression of the Sr5 gene in mesophyll but not in epidermal cells. In contrast, the Sr6 gene was more effective in the Chinese Spring background than in the Prelude background.Rust development in leaves with or without the Sr8 gene was the same up to 60 h after incubation, when incompatibility in resistant plants was first detected by the appearance of fluorescing host cells. By 72 h, mean colony size in resistant leaves was smaller than that in susceptible leaves, evidently because growth of runner hyphae was inhibited. Apparently, the P8 gene for avirulence was not expressed until colonies had reached considerable size. In leaves containing the Sr22 gene for resistance, the sequence of histological events was similar to that in leaves containing Sr8, but fluorescing host cells appeared later (72 h) and colony growth was inhibited only at 96 h after incubation. In both of these interactions, fluorescing host cells developed at the periphery of colonies when incompatibility was expressed. The host-parasite interaction in cells invaded before that time remained compatible even at later stages of colony development. In leaves containing the Sr5 or the Sr8 gene, but not in those with the Sr6 gene, the growth of some colonies was inhibited although they were not associated with fluorescing host cells. Evidently, host-cell necrosis was closely associated with reduced fungal growth in interactions involving Sr6, but not in interactions involving the resistance genes Sr5 and Sr8.

Host–parasite relationships and development of the ergot sclerotium in Claviceps purpurea

1980 ◽  
Vol 58 (8) ◽  
pp. 942-958 ◽  
Author(s):  
E. S. Luttrell
Keyword(s):  
Vascular Bundle ◽  
Secale Cereale ◽  
Epidermal Cells ◽  
Host Cells ◽  
Claviceps Purpurea ◽  
Conducting Tissue ◽  
Storage Cells ◽  
Host Parasite ◽  
Central Strand ◽  
Host Tissues

Conidia of Claviceps purpurea germinate on the stigmas of Secale cereale, and intercellular hyphae grow downward through the style and inner wall of the ovary to the tip of the rachilla. Across the tip of the rachilla, hyphae surrounding living host cells form a narrow interface that plunges downward into the central vascular bundle approximately to the level of origin of the lodicules. This biotrophic relationship is well established 5–6 days after infection at anthesis and persists unaltered through maturation of the ergot sclerotium at approximately the 28th day. Tissues in the base of the ovary above this interface are destroyed and replaced by fungus stroma. Xylem vessels in the tip of the rachilla are destroyed and replaced by a hyphal core extending downward from the stromatic foot of the fungus. Hyphae emerging between the epidermal cells of the ovary form an external matrix that contributes to further expansion of the stroma. A palisade of phialidic conidiophores develops over the surface of the stroma, which is involuted into labyrinthine chambers. Conidia ooze from the florets in drops of honeydew by the 6th or 7th day. The ovarian cap and the upper part of the ovule are pushed upward on the apex of the conidial stroma, and some of these isolated host cells remain alive until the 11th day. A layer of vertically arranged parallel hyphae across the base of the conidial stroma forms a generative zone that sharply delimits the basal stromatic foot seated in the floret and by apically directed intercalary growth produces the compact tissues of the ergot sclerotium. The sclerotium begins to protrude from the floret by the 11th day. The withered remnants of the conidial stroma and the ovarian cap are carried upward on the tip of the massive sclerotium. Beneath the dark rind the hyaline tissue of the sclerotium consists primarily of compacted, isodiametric storage cells. A loose hyphal conducting tissue forms a central strand from which narrow vanes radiate irregularly toward the periphery. Ergot of rye is a replacement disease in which the parasite disintegrates host tissues in areas required for development of its own structures while maintaining a compatible relationship with adjacent host cells as a source of water and nutrients.

scholarly journals Exploiting RNA thermometer-driven molecular bioprocess control as a concept for heterologous rhamnolipid production

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Philipp Noll ◽  
Chantal Treinen ◽  
Sven Müller ◽  
Lars Lilge ◽  
Rudolf Hausmann ◽  
...  
Keyword(s):  
High Titer ◽  
Production Capacity ◽  
Batch Process ◽  
Product Formation ◽  
Effect Of Temperature ◽  
Industrial Biotechnology ◽  
Temperature Sensitive ◽  
Translation Control ◽  
Rhamnolipid Production ◽  
Rna Thermometer

AbstractA key challenge to advance the efficiency of bioprocesses is the uncoupling of biomass from product formation, as biomass represents a by-product that is in most cases difficult to recycle efficiently. Using the example of rhamnolipid biosurfactants, a temperature-sensitive heterologous production system under translation control of a fourU RNA thermometer from Salmonella was established to allow separating phases of preferred growth from product formation. Rhamnolipids as bulk chemicals represent a model system for future processes of industrial biotechnology and are therefore tied to the efficiency requirements in competition with the chemical industry. Experimental data confirms function of the RNA thermometer and suggests a major effect of temperature on specific rhamnolipid production rates with an increase of the average production rate by a factor of 11 between 25 and 38 °C, while the major part of this increase is attributable to the regulatory effect of the RNA thermometer rather than an unspecific overall increase in bacterial metabolism. The production capacity of the developed temperature sensitive-system was evaluated in a simple batch process driven by a temperature switch. Product formation was evaluated by efficiency parameters and yields, confirming increased product formation rates and product-per-biomass yields compared to a high titer heterologous rhamnolipid production process from literature.

A light and electron microscope study of the fungal endophytes in the sporophyte and gametophyte of Lycopodium cernuum with observations on the gametophyte–sporophyte junction

1992 ◽  
Vol 70 (1) ◽  
pp. 58-72 ◽  
Author(s):  
Jeffrey G. Duckett ◽  
Roberto Ligrone
Keyword(s):  
Root Nodules ◽  
Fungal Endophytes ◽  
Fungal Endophyte ◽  
Peninsular Malaysia ◽  
Epidermal Cells ◽  
Host Cells ◽  
Wall Material ◽  
Intercellular Spaces ◽  
Host Cytoplasm ◽  
Fungal Associations

The ventral epidermal cells of the photosynthetic, surface-living gametophytes of Lycopodium cernuum, collected from moist shaded banks in Peninsular Malaysia, contain an aseptate fungus. In some cells the hyphae are thick walled and form coils encapsulated by a thin layer of host wall material. In others the fungus is thin walled and shows limited differentiation into larger trunk hyphae and arbuscules. The adjacent host cytoplasm, separated from the fungus by a granular interfacial matrix, contains numerous chloroplasts, mitochondria, and microtubules. The hyphae contact the substratum via the ventral walls of the epidermal cells and the rhizoids are free from infection. In the protocorm and root nodules, aseptate hyphae initially colonize mucilage-filled schizogenous intercellular spaces. Subsequent invasion of the host cells is associated with the development of massive overgrowths of host wall material. The fungal associations in L. cernuum share a mixture of attributes otherwise found in different angiosperm mycorrhizae and in mycotrophic relationships in liverworts. Wall ingrowths are present in both the gametophyte and sporophyte cells in the placenta of L. cernuum. The very limited development of the placenta, compared with L. appressum, certain bryophytes and ferns, the diminutive size, and early senescence of the gametophytes of L. cernuum are all linked to the presence of the protocorm. This massive absorptive organ, homologous to a foot, in terms of its position in sporophyte ontogeny, but external to the parent gametophyte, derives its nutrition partly from photosynthesis and partly from its fungal endophyte. Key words: chloroplasts, Lycopodium, mycorrhiza, pteridophytes, root nodules, symbiosis, transfer cells.

scholarly journals Modelling tree ring cellulose <i>δ</i><sup>18</sup>O variations in two temperature-sensitive tree species from North and South America

2017 ◽  
Vol 13 (11) ◽  
pp. 1515-1526 ◽  
Author(s):  
Aliénor Lavergne ◽  
Fabio Gennaretti ◽  
Camille Risi ◽  
Valérie Daux ◽  
Etienne Boucher ◽  
...  
Keyword(s):  
South America ◽  
Isotopic Fractionation ◽  
Circulation Model ◽  
Effect Of Temperature ◽  
Temperature Sensitive ◽  
Nothofagus Pumilio ◽  
Climate Signal ◽  
North And South America ◽  
North And South ◽  
Two Temperature

Abstract. Oxygen isotopes in tree rings (δ18OTR) are widely used to reconstruct past climates. However, the complexity of climatic and biological processes controlling isotopic fractionation is not yet fully understood. Here, we use the MAIDENiso model to decipher the variability in δ18OTR of two temperature-sensitive species of relevant palaeoclimatological interest (Picea mariana and Nothofagus pumilio) and growing at cold high latitudes in North and South America. In this first modelling study on δ18OTR values in both northeastern Canada (53.86° N) and western Argentina (41.10° S), we specifically aim at (1) evaluating the predictive skill of MAIDENiso to simulate δ18OTR values, (2) identifying the physical processes controlling δ18OTR by mechanistic modelling and (3) defining the origin of the temperature signal recorded in the two species. Although the linear regression models used here to predict daily δ18O of precipitation (δ18OP) may need to be improved in the future, the resulting daily δ18OP values adequately reproduce observed (from weather stations) and simulated (by global circulation model) δ18OP series. The δ18OTR values of the two species are correctly simulated using the δ18OP estimation as MAIDENiso input, although some offset in mean δ18OTR levels is observed for the South American site. For both species, the variability in δ18OTR series is primarily linked to the effect of temperature on isotopic enrichment of the leaf water. We show that MAIDENiso is a powerful tool for investigating isotopic fractionation processes but that the lack of a denser isotope-enabled monitoring network recording oxygen fractionation in the soil–vegetation–atmosphere compartments limits our capacity to decipher the processes at play. This study proves that the eco-physiological modelling of δ18OTR values is necessary to interpret the recorded climate signal more reliably.

scholarly journals Proteomic Analysis of Leishmania donovani Membrane Components Reveals the Role of Activated Protein C Kinase in Host-Parasite Interaction

Pathogens ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 1194
Author(s):  
Sandeep Verma ◽  
Deepak Kumar Deep ◽  
Poonam Gautam ◽  
Ruchi Singh ◽  
Poonam Salotra
Keyword(s):  
Membrane Proteins ◽  
Protein C ◽  
Leishmania Donovani ◽  
Parasitic Infection ◽  
Activated Protein C ◽  
Host Cells ◽  
Filamin A ◽  
Related Factors ◽  
Interacting Protein ◽  
Host Parasite

Visceral leishmaniasis (VL), mainly caused by the Leishmania donovani parasitic infection, constitutes a potentially fatal disease, for which treatment is primarily dependent on chemotherapy. The emergence of a resistant parasite towards current antileishmanial agents and increasing reports of relapses are the major concerns. Detailed research on the molecular interaction at the host-parasite interface may provide the identification of the parasite and the host-related factors operating during disease development. Genomic and proteomic studies highlighted several essential secretory and cytosolic proteins that play vital roles during Leishmania pathogenesis. The aim of this study was to identify membrane proteins from the Leishmania donovani parasite and the host macrophage that interact with each other using 2-DE/MALDI-TOF/MS. We identified membrane proteins including activated protein C kinase, peroxidoxin, small myristoylated protein 1 (SMP-1), and cytochrome C oxidase from the parasite, while identifying filamin A interacting protein 1(FILIP1) and β-actin from macrophages. We further investigated parasite replication and persistence within macrophages following the macrophage-amastigote model in the presence or absence of withaferin (WA), an inhibitor of activated C kinase. WA significantly reduced Leishmania donovani replication within host macrophages. This study sheds light on the important interacting proteins for parasite proliferation and virulence, and the establishment of infection within host cells, which can be targeted further to develop a strategy for chemotherapeutic intervention.

scholarly journals How does temperature affect the dynamics of SARS-CoV-2 M proteins? Insights from Molecular Dynamics Simulations

2021 ◽  
Author(s):  
Soumya Lipsa Rath ◽  
Madhusmita Tripathy ◽  
Nabanita Mandal
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulations ◽  
Membrane Lipids ◽  
Membrane System ◽  
Host Cells ◽  
Coarse Grained ◽  
M Protein ◽  
Effect Of Temperature ◽  
M Proteins ◽  
Dynamics Simulations

Enveloped viruses, in general, have several transmembrane proteins and glycoproteins, which assist the virus in entry and attachment onto the host cells. These proteins also play a significant role in determining the shape and size of the newly formed virus particles. The lipid membrane and the embedded proteins affect each other in non-trivial ways during the course of the viral life cycle. Unravelling the nature of the protein-protein and protein-lipid interactions, under various environmental and physiological conditions, could therefore prove to be crucial in development of therapeutics. Here, we study the M protein of SARS-CoV-2 to understand the effect of temperature on the properties of the protein-membrane system. The membrane embedded dimeric M proteins were studied using atomistic and coarse-grained molecular dynamics simulations at temperatures ranging between 10 and 50 ˚C. While temperature induced fluctuations should be monotonic, we observe a steady rise in the protein dynamics up to 40 ˚C, beyond which it surprisingly reverts back to the low temperature behaviour. Detailed investigation reveals disordering of the membrane lipids in the presence of the protein, which induces additional curvature around the transmembrane region. Coarse-grained simulations indicate temperature dependent aggregation of M protein dimers. Our study clearly indicates that the dynamics of membrane lipids and integral M protein of SARS-CoV-2 enables it to better associate and aggregate only at a certain temperature range (i.e., ~30 to 40 ˚C). This can have important implications in the protein aggregation and subsequent viral budding/fission processes.   

scholarly journals Understanding the effect of temperature on Bluetongue disease risk in livestock

2019 ◽  
Author(s):  
Fadoua El Moustaid ◽  
Zorian Thronton ◽  
Hani Slamani ◽  
Sadie J. Ryan ◽  
Leah R. Johnson
Keyword(s):  
Disease Risk ◽  
Vector Competence ◽  
Basic Reproductive Number ◽  
Effect Of Temperature ◽  
Reproductive Number ◽  
Temperature Sensitive ◽  
Modeling Tools ◽  
Vector Borne Diseases ◽  
Thermal Range ◽  
Vector Borne

AbstractThe transmission of vector-borne diseases is governed by complex factors including pathogen characteristics, vector-host interactions, and environmental conditions. Temperature is a major driver for many vector-borne diseases including Bluetongue viral (BTV) disease, a midge-borne febrile disease of ruminants, notably livestock, whose etiology ranges from mild or asymptomatic to rapidly fatal, thus threatening animal agriculture and the economy of affected countries. Using modeling tools, we seek to predict where transmission can occur based on suitable temperatures for BTV. We fit thermal performance curves to temperature sensitive midge life history traits, using a Bayesian approach. Then, we incorporated these into a new formula for the disease basic reproductive number, R0, to include trait responses, for two species of key midge vectors, Culicoides sonorensis and Culicoides variipennis. Our results show that outbreaks of BTV are more likely between 15°C and 33°C with predicted peak transmission at 26°C. The greatest uncertainty in R0 is associated with the uncertainty in: mortality and fecundity of midges near optimal temperature for transmission; midges’ probability of becoming infectious post infection at the lower edge of the thermal range; and the biting rate together with vector competence at the higher edge of the thermal range. We compare our R0 to two other R0 formulations and show that incorporating thermal curves into all three leads to similar BTV risk predictions. To demonstrate the utility of this model approach, we created global suitability maps indicating the areas at high and long-term risk of BTV transmission, to assess risk, and anticipate potential locations of establishment.

scholarly journals Drug Discovery for Chagas Disease: Impact of Different Host Cell Lines on Assay Performance and Hit Compound Selection

2019 ◽  
Vol 4 (2) ◽  
pp. 82 ◽  
Author(s):  
Caio Haddad Franco ◽  
Laura Maria Alcântara ◽  
Eric Chatelain ◽  
Lucio Freitas-Junior ◽  
Carolina Borsoi Moraes
Keyword(s):  
Drug Discovery ◽  
Host Cell ◽  
Cell Lines ◽  
Chagas Disease ◽  
Host Cells ◽  
Mammalian Cell Lines ◽  
Starting Point ◽  
Disease Impact ◽  
Screening Assays ◽  
Host Parasite

Cell-based screening has become the major compound interrogation strategy in Chagas disease drug discovery. Several different cell lines have been deployed as host cells in screening assays. However, host cell characteristics and host-parasite interactions may play an important role when assessing anti-T. cruzi compound activity, ultimately impacting on hit discovery. To verify this hypothesis, four distinct mammalian cell lines (U2OS, THP-1, Vero and L6) were used as T. cruzi host cells in High Content Screening assays. Rates of infection varied greatly between different host cells. Susceptibility to benznidazole also varied, depending on the host cell and parasite strain. A library of 1,280 compounds was screened against the four different cell lines infected with T. cruzi, resulting in the selection of a total of 82 distinct compounds as hits. From these, only two hits were common to all four cell lines assays (2.4%) and 51 were exclusively selected from a single assay (62.2%). Infected U2OS cells were the most sensitive assay, as 55 compounds in total were identified as hits; infected THP-1 yielded the lowest hit rates, with only 16 hit compounds. Of the selected hits, compound FPL64176 presented selective anti-T. cruzi activity and could serve as a starting point for the discovery of new anti-chagasic drugs.

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