Anatomy of Pilostyles hamiltonii C. A. Gardner (Rafflesiaceae) in stems of Daviesia

1982 ◽  
Vol 30 (1) ◽  
pp. 1 ◽  
Author(s):  
B Dell ◽  
J Kuo ◽  
AH Burbidge
Keyword(s):  
Vegetative Growth ◽  
Host Cells ◽  
Vascular Cambium ◽  
Flower Initiation ◽  
Nutrient Requirements ◽  
Secondary Phloem ◽  
Undifferentiated Cells ◽  
Host Parasite

In Daviesia stems the vegetative body of Pilostyles hamiltonii occurs as thin strands of undifferentiated cells within the secondary phloem of the host. Parasite cells have prominent nuclei, extended plasmalemma, and lack chloroplasts and amyloplasts. Plasmodesmata are abundant between parasite and host cells. Early vegetative growth of the parasite appears to depend on host phloem tissues for its nutrient requirements. At flower initiation Pilostyles taps the host xylem by producing pegs of tissue across the vascular cambium of the host.

New class of polyomavirus mutant that can persist as free copies in F9 embryonal carcinoma cells

1986 ◽  
Vol 6 (11) ◽  
pp. 3920-3927
Author(s):  
K Ariizumi ◽  
H Ariga
Keyword(s):  
Embryonal Carcinoma ◽  
Regulatory Region ◽  
Host Cells ◽  
Circular Dna ◽  
New Class ◽  
Differentiated Cells ◽  
Copy Numbers ◽  
Undifferentiated Cells ◽  
Ec Cells ◽  
F9 Embryonal Carcinoma Cells

A small circular DNA was found extrachromosomally in a clone of F9 embryonal carcinoma (EC) cells at high copy numbers per cell. The DNA was cloned in plasmid pUC19. Restriction endonuclease analyses of the DNA indicated that the DNA (fPyF9) was a mutant of polyomavirus (Py) DNA and had a mutation in a noncoding regulatory region. There have been many reports on the isolation of Py mutants capable of replication in undifferentiated cells. However, fPyF9 was different from other Py mutants in the following aspects: it was harbored stably as a free copy at 1 X 10(4) to 5 X 10(4) copies per cell in EC cells; it replicated in undifferentiated cells better than in differentiated cells; it was extremely rearranged in the sequences of the enhancer B domain; and it carried in the enhancer B domain three copies of an exogenous sequence which does not exist in Py strain A2. From these observations, we propose a new class of Py EC mutant which has an autonomous state similar to that of plasmid and small circular DNA in host 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 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.

Phi Thickenings in Fossil Seed Plants from Antarctica

IAWA Journal ◽  
1987 ◽  
Vol 8 (3) ◽  
pp. 191-201 ◽  
Author(s):  
Michael A. Millay ◽  
Thomas N. Taylor ◽  
Edith L. Taylor
Keyword(s):  
Middle Triassic ◽  
Cell Layer ◽  
Vascular Cambium ◽  
Secondary Development ◽  
Water Regulation ◽  
Secondary Phloem ◽  
Primary Xylem ◽  
Sieve Cells ◽  
Ray Parenchyma ◽  
Cell Layers

Primary anatomy and secondary development is described for two root types from the Fremouw Peak locality (Transantarctic Mts, Antarctica) of early to middle Triassic age. Roots of Antarcticycas have a bilayered cortex with thick surface cuticle, diarch xylem, and a clearIy defined endodermis surrounded by a single cell layer possessing phi thickenings. Secondary development begins with phellern and phelloderm production from the out er primary phloem position, and is followed bya bifacial vascular cambium next to the primary xylem that pro duces sieve cells and ray parenchyma to the outside. Young roots of Antarcticoxylon are similar to those of Antarcticycas, but may possess 2-3 cell layers with phi thickenings. Secondary development from a bifacial vascular cambium produces alternating bands of sieve cells and phloem parenchyma cells in the secondary phloem and wood with uniseriate rays and scattered axial parenchyma. The presence of phi thickenings and an epidermal cutieie in both roots suggests environmental stress related to water regulation. The occurrence of phi thickenings in the roots of some conifers, angiosperms, a fossil cycad and a probable seed fern suggests this character is of ecological rather than phylogenetic significance.

Development of Included Phloem in the Stem of Combretum Nigricans (Combretaceae)

IAWA Journal ◽  
1995 ◽  
Vol 16 (2) ◽  
pp. 151-158 ◽  
Author(s):  
R. W. den Outer ◽  
W. L. H. van Veenendaal
Keyword(s):  
Secondary Xylem ◽  
Vascular Cambium ◽  
Secondary Phloem ◽  
Xylem Parenchyma ◽  
Long Period ◽  
Short Period ◽  
Outer Border

The development of diffuse included phloem strands in Combretum nigricans sterns is described, During a short period of time, a small phloem strand is cut off locally in an inward direction by an otherwise normal bidirectional vascular cambium. This contrasts with previous descriptions and interpretations because these strands are not formed after redifferentiation of secondary xylem parenchyma. A complementary cambium formed at the inner border of the young strand somewhat enlarges the strand and, during a relatively long period, produces secondary phloem outwards. Finally this complementary cambium stops functioning as a cambium and merges with the secondary phloem it has produced. Radial rows of cells are present within the included phloem strands which continue into the later-formed secondary xylem; rays transverse the strands. Crushing of the phloem takes place near the outer border of the strand, forming cap-like tissues of disorganized cells.

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.

The anatomy of Santalum album (Sandalwood) haustoria

2006 ◽  
Vol 84 (10) ◽  
pp. 1608-1616 ◽  
Author(s):  
Kushan U. Tennakoon ◽  
Duncan D. Cameron
Keyword(s):  
Mass Flow ◽  
Applied Pressure ◽  
Host Cells ◽  
Santalum Album ◽  
Cell Wall Degrading Enzymes ◽  
Hyaline Body ◽  
Direct Pressure ◽  
Xylem Tissue ◽  
Host Parasite ◽  
Santalum Album L

Structural attributes of Santalum album L. (Sandalwood) haustoria have been long overlooked in the literature. This is surprising since successful haustorial formation is key to the survival of individuals of this ecologically and economically important plant. We investigated the morphology of haustoria formed by S. album attached to one of its principal hosts Tithonia diversifolia (Hemsley) A. Gray. The bell-shaped mature haustoria were composed of a peripheral hyaline body and a centrally located penetration peg. The parasite penetration peg can penetrate the host by means of direct pressure and the secretion of cell-wall-degrading enzymes when forming a successful graft union. The latter mechanism is supported by this study as we observed no evidence of collapsed host cells as the result of parasite applied pressure. Upon reaching the xylem tissue of the host root, the penetration peg formed a thin ellipsoidal disc and the host–parasite interface was almost entirely composed of parenchymatous tissue. Luminal continuities were absent between the xylem conducting tissues of the partners, thus suggesting mass flow of solutes is unlikely to occur in this association. High densities of contact parenchyma were found at the host–parasite interface; thus it is probable that these are the principal structures formed by the parasite that facilitate the acquisition of host-derived xylem resources. This study therefore concludes that haustorial anatomy of S. album supports cross membrane (potentially selective) uptake of host-derived solutes as opposed to mass flow via vascular continuity.

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.

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