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 Characterisation of Trichuris muris secreted proteins and extracellular vesicles provides new insights into host-parasite communication

2017 ◽  
Author(s):  
Ramon M. Eichenberger ◽  
Md Hasanuzzaman Talukder ◽  
Matthew A. Field ◽  
Phurpa Wangchuk ◽  
Paul Giacomin ◽  
...  
Keyword(s):  
Extracellular Vesicles ◽  
Control Measures ◽  
Host Cells ◽  
Parasitic Nematodes ◽  
Trichuris Muris ◽  
Future Studies ◽  
Secretory Products ◽  
Host Parasite ◽  
First Time ◽  
Host Tissues

AbstractWhipworms are parasitic nematodes that live in the gut of more than 500 million people worldwide. Due to the difficulty in obtaining parasite material, the mouse whipworm Trichuris muris has been extensively used as a model to study human whipworm infections. These nematodes secrete a multitude of compounds that interact with host tissues where they orchestrate a parasitic existence. Herein we provide the first comprehensive characterisation of the excretory/secretory products of T. muris. We identify 148 proteins secreted by T. muris and show for the first time that the mouse whipworm secretes exosome-like extracellular vesicles (EVs) that can interact with host cells. We use an Optiprep® gradient to purify the EVs, highlighting the suitability of this method for purifying EVs secreted by a parasitic nematode. We also characterise the proteomic and genomic content of the EVs, identifying >350 proteins, 56 miRNAs (22 novel) and 475 full-length mRNA transcripts mapping to T. muris gene models. Many of the miRNAs putatively mapped to mouse genes involved in regulation of inflammation, implying a role in parasite-driven immunomodulation. In addition, for the first time to our knowledge, we use colonic organoids to demonstrate the internalisation of parasite EVs by host cells. Understanding how parasites interact with their host is crucial to develop new control measures. This first characterisation of the proteins and EVs secreted by T. muris provides important information on whipworm-host communication and forms the basis for future studies.

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.

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 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 Host-Parasite Interaction between Parasitic Cymothoid Ceratothoa oestroides and Its Host, Farmed European Sea Bass (Dicentrarchus labrax)

Pathogens ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 230
Author(s):  
Ivona Mladineo ◽  
Jerko Hrabar ◽  
Olja Vidjak ◽  
Ivana Bočina ◽  
Slavica Čolak ◽  
...  
Keyword(s):  
Dicentrarchus Labrax ◽  
Aegean Sea ◽  
Sea Bass ◽  
Condition Index ◽  
Bacterial Biofilm ◽  
Body Parts ◽  
Farmed Fish ◽  
European Sea Bass ◽  
Host Parasite ◽  
Host Tissues

Parasitic isopod Ceratothoa oestroides (Cymothoidea, Isopoda) is a common and generalist buccal cavity-dweller in marine fish, recognised for its detrimental effect in fingerling and juvenile farmed European sea bass (Dicentrarchus labrax). Although distributed throughout the Mediterranean, the isopod provokes acute outbreaks mainly limited to particular endemic areas in Croatia (Adriatic Sea) and Greece (Aegean Sea). While numerous studies have previously evidenced its gross effect on farmed fish (i.e. decreased condition index, slower growth rate, lethargy and mortality), details on the host-parasite interaction are still lacking. Therefore, using a multimethodological approach, we closely examined the structure and appearance of isopod body parts acting in the attachment and feeding (stereomicroscopy, scanning and transmission electron microscopy), and the extent of host tissues damage (histology, immunohistochemistry, micro-computational tomography) induced by parasitation. Interestingly, while hematophagous nature of the parasite has been previously postulated we found no unambiguous data to support this; we observed host tissues fragmentation and extensive hyperplasia at the parasitation site, and no structures indicative of heme detoxifying mechanisms in the parasite gut, or other traces of a blood meal. The bacterial biofilm covering C. oestroides mouthparts and pereopods suggests that the isopod may play a role in conveying secondary pathogens to the infected host, or alternatively, it serves the parasite in normal interaction with its environment.

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.

A survey of stomatal movements and associated potassium fluxes in the plant kingdom

1973 ◽  
Vol 51 (1) ◽  
pp. 37-42 ◽  
Author(s):  
C. M. Willmer ◽  
J. E. Pallas Jr.
Keyword(s):  
Epidermal Cells ◽  
Evolutionary Development ◽  
Grass Species ◽  
Arachis Hypogaea L ◽  
Evolutionary Level ◽  
Glycine Max L ◽  
Histochemical Tests ◽  
Subsidiary Cells ◽  
Stomatal Movements ◽  
Storage Cells

Histochemical tests for K+ were carried out on the epidermis of aerial organs from plants which varied in evolutionary development (e.g., clubmosses, ferns, angiosperms) and general morphology (e.g., monocotyledons, succulent dicotyledons, woody dicotyledons). These tests made on epidermal tissue with open or closed stomata suggested that K+ transport is implicated in stomatal movements regardless of the evolutionary level and the stomatal location in the plants investigated. In all species that displayed substantial stomatal opening, K+ was detectable in the guard cells. With small stomatal apertures, K+ was located in guard and subsidiary cells of Commelina communis L. leaves and Glycine max. L. cotyledons. When stomata were closed, K+ was detectable in the subsidiary cells of all the grass species, Kalanchoë pinnata Pers., C. communis, and, occasionally, in the epidermal cells surrounding the stomata of some ferns. A condition was also observed when virtually no K+ was detectable in the guard or subsidiary cells of C. communis leaves or G. max cotyledons. Commonly, when stomata were closed, K+ was not detectable in any cells of the epidermis. Exceptions were the "K+ storage cells," trichomes and epidermal cells of Arachis hypogaea L., and in the more primitive plants from and including the level of the ferns.

scholarly journals Ultrastructure of the Infection of Sorghum bicolor by Colletotrichum sublineolum

2001 ◽  
Vol 91 (2) ◽  
pp. 149-158 ◽  
Author(s):  
P. S. Wharton ◽  
A. M. Julian ◽  
R. J. O'Connell
Keyword(s):  
Cell Wall ◽  
Sorghum Bicolor ◽  
Epidermal Cells ◽  
Host Cells ◽  
Wall Thickening ◽  
Fungal Cell ◽  
Resistant Cultivars ◽  
Ultrastructural Studies ◽  
Opaque Material ◽  
Colletotrichum Sublineolum

Ultrastructural studies of the infection of susceptible and resistant cultivars of Sorghum bicolor by Colletotrichum sublineolum were conducted. Initial penetration events were the same on both susceptible and resistant cultivars. Germ tubes originating from germinated conidia formed globose, melanized appressoria, that penetrated host epidermal cells directly. Appressoria did not produce appressorial cones, but each penetration pore was surrounded by an annular wall thickening. Inward deformation of the cuticle and localized changes in staining properties of the host cell wall around the infection peg suggests that penetration involves both mechanical force and enzymic dissolution. In compatible interactions, penetration was followed by formation of biotrophic globular infection vesicles in epidermal cells. Filamentous primary hyphae developed from the vesicles and went on to colonize many other host cells as an intracellular mycelium. Host cells initially survived penetration. The host plasma membrane invaginated around infection vesicles and primary hyphae and was appressed tightly to the fungal cell wall, with no detectable matrix layer at the interface. Necrotrophic secondary hyphae appeared after 66 h and ramified through host tissue both intercellularly and intracellularly, forming hypostromatic acervuli by 114 h. Production of secondary hyphae was accompanied by the appearance of electron-opaque material within infected cells. This was thought to represent the host phytoalexin response. In incompatible interactions, infection vesicles and primary hyphae were formed in epidermal cells by 42 h. However, they were encrusted with electron-opaque material and appeared dead. These observations are discussed in relation to the infection processes of other Colletotrichum spp. and the host phytoalexin response.

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.

scholarly journals Who's really in control: microbial regulation of protein trafficking in the epithelium

2014 ◽  
Vol 306 (3) ◽  
pp. C187-C197 ◽  
Author(s):  
Matthew R. Hendricks ◽  
Jennifer M. Bomberger
Keyword(s):  
Epithelial Cell ◽  
Protein Trafficking ◽  
Host Cells ◽  
Eukaryotic Cells ◽  
Cell Physiology ◽  
Cellular Physiology ◽  
Cellular Processes ◽  
Complex Interactions ◽  
Host Pathogen ◽  
Host Tissues

Due to evolutionary pressure, there are many complex interactions at the interface between pathogens and eukaryotic host cells wherein host cells attempt to clear invading microorganisms and pathogens counter these mechanisms to colonize and invade host tissues. One striking observation from studies focused on this interface is that pathogens have multiple mechanisms to modulate and disrupt normal cellular physiology to establish replication niches and avoid clearance. The precision by which pathogens exert their effects on host cells makes them excellent tools to answer questions about cell physiology of eukaryotic cells. Furthermore, an understanding of these mechanisms at the host-pathogen interface will benefit our understanding of how pathogens cause disease. In this review, we describe a few examples of how pathogens disrupt normal cellular physiology and protein trafficking at epithelial cell barriers to underscore how pathogens modulate cellular processes to cause disease and how this knowledge has been utilized to learn about cellular physiology.

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