scholarly journals Expression of Anaplasma marginale Ankyrin Repeat-Containing Proteins during Infection of the Mammalian Host and Tick Vector

2011 ◽  
Vol 79 (7) ◽  
pp. 2847-2855 ◽  
Author(s):  
Solomon S. Ramabu ◽  
David A. Schneider ◽  
Kelly A. Brayton ◽  
Massaro W. Ueti ◽  
Telmo Graça ◽  
...  
Keyword(s):  
Host Cell ◽  
Nuclear Localization ◽  
Cell Nucleus ◽  
Anaplasma Marginale ◽  
Cell Types ◽  
Mammalian Host ◽  
Specific Cell ◽  
Content Type ◽  
Tick Vector ◽  
Host Cell Nucleus

ABSTRACTTransmission of tick-borne pathogens requires transition between distinct host environments with infection and replication in host-specific cell types.Anaplasma marginaleillustrates this transition: in the mammalian host, the bacterium infects and replicates in mature (nonnucleated) erythrocytes, while in the tick vector, replication occurs in nucleated epithelial cells. We hypothesized that proteins containing ankyrin motifs would be expressed byA. marginaleonly in tick cells and would traffic to the infected host cell nucleus.A. marginaleencodes three proteins containing ankyrin motifs, an AnkA orthologue (the AM705 protein), AnkB (the AM926 protein), and AnkC (the AM638 protein). All threeA. marginaleAnks were confirmed to be expressed during intracellular infection: AnkA is expressed at significantly higher levels in erythrocytes, AnkB is expressed equally by both infected erythrocytes and tick cells, and AnkC is expressed exclusively in tick cells. There was no evidence of any of the Ank proteins trafficking to the nucleus. Thus, the hypothesis that ankyrin-containing motifs were predictive of cell type expression and nuclear localization was rejected. In contrast, AnkA orthologues in the closely relatedA. phagocytophilumandEhrlichia chaffeensishave been shown to localize to the host cell nucleus. This difference, together with the lack of a nuclear localization signal in any of the AnkA orthologues, suggests that trafficking may be mediated by a separate transporter rather than by endogenous signals. Selection for divergence in Ank function amongAnaplasmaandEhrlichiaspp. is supported by both locus and allelic analyses of genes encoding orthologous proteins and their ankyrin motif compositions.

scholarly journals Superinfection Exclusion of the Ruminant Pathogen Anaplasma marginale in Its Tick Vector Is Dependent on the Time between Exposures to the Strains

2016 ◽  
Vol 82 (11) ◽  
pp. 3217-3224 ◽  
Author(s):  
Susan M. Noh ◽  
Michael J. Dark ◽  
Kathryn E. Reif ◽  
Massaro W. Ueti ◽  
Lowell S. Kappmeyer ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Anaplasma Marginale ◽  
Host Population ◽  
Mammalian Host ◽  
Content Type ◽  
Tropical Regions ◽  
Superinfection Exclusion ◽  
Tick Vector ◽  
Exposure Interval ◽  
Vector Borne

ABSTRACTThe remarkable genetic diversity of vector-borne pathogens allows for the establishment of superinfection in the mammalian host. To have a long-term impact on population strain structure, the introduced strains must also be transmitted by a vector population that has been exposed to the existing primary strain. The sequential exposure of the vector to multiple strains frequently prevents establishment of the second strain, a phenomenon termed superinfection exclusion. As a consequence, superinfection exclusion may greatly limit genetic diversity in the host population, which is difficult to reconcile with the high degree of genetic diversity maintained among vector-borne pathogens. UsingAnaplasma marginale, a tick-borne bacterial pathogen of ruminants, we hypothesized that superinfection exclusion is temporally dependent and that longer intervals between strain exposures allow successful acquisition and transmission of a superinfecting strain. To test this hypothesis, we sequentially exposedDermacentor andersoniticks to two readily tick-transmissible strains ofA. marginale. The tick feedings were either immediately sequential or 28 days apart. Ticks were allowed to transmission feed and were individually assessed to determine if they were infected with one or both strains. The second strain was excluded from the tick when the exposure interval was brief but not when it was prolonged. Midguts and salivary glands of individual ticks were superinfected and transmission of both strains occurred only when the exposure interval was prolonged. These findings indicate that superinfection exclusion is temporally dependent, which helps to account for the differences in pathogen strain structure in tropical compared to temperate regions.IMPORTANCEMany vector-borne pathogens have marked genetic diversity, which influences pathogen traits such as transmissibility and virulence. The most successful strains are those that are preferentially transmitted by the vector. However, the factors that determine successful transmission of a particular strain are unknown. In the case of intracellular, bacterial, tick-borne pathogens, one potential factor is superinfection exclusion, in which colonization of ticks by the first strain of a pathogen it encounters prevents the transmission of a second strain. UsingA. marginale, the most prevalent tick-borne pathogen of cattle worldwide, and its natural tick vector, we determined that superinfection exclusion occurs when the time between exposures to two strains is brief but not when it is prolonged. These findings suggest that superinfection exclusion may influence strain transmission in temperate regions, where tick activity is limited by season, but not in tropical regions, where ticks are active for long periods.

Lysis of bacterioids in the vicinity of the host cell nucleus in an ineffective (fix-) root nodule of soybean (Glycine max)

Planta ◽  
1984 ◽  
Vol 162 (1) ◽  
pp. 8-16 ◽  
Author(s):  
Dietrich Werner ◽  
Erhard M�rschel ◽  
Renate Kort ◽  
Robert B. Mellor ◽  
Stephan Bassarab
Keyword(s):  
Glycine Max ◽  
Host Cell ◽  
Cell Nucleus ◽  
Root Nodule ◽  
Host Cell Nucleus

scholarly journals The journey of herpesvirus capsids and genomes to the host cell nucleus

2021 ◽  
Vol 50 ◽  
pp. 147-158
Author(s):  
Katinka Döhner ◽  
Angela Cornelius ◽  
Manutea Christophe Serrero ◽  
Beate Sodeik
Keyword(s):  
Host Cell ◽  
Cell Nucleus ◽  
Host Cell Nucleus

Yersinia pestis and plague

2003 ◽  
Vol 31 (1) ◽  
pp. 104-107 ◽  
Author(s):  
R.W. Titball ◽  
J. Hill ◽  
D.G. Lawton ◽  
K.A. Brown
Keyword(s):  
Host Cell ◽  
Yersinia Pestis ◽  
Genome Sequence ◽  
Yersinia Pseudotuberculosis ◽  
Cell Types ◽  
Mammalian Host ◽  
Aetiological Agent ◽  
Mild Disease ◽  
Regulatory Systems ◽  
Obligate Pathogen

Yersinia pestis is the aetiological agent of plague, a disease of humans that has potentially devastating consequences. Evidence indicates that Y. pestis evolved from Yersinia pseudotuberculosis, an enteric pathogen that normally causes a relatively mild disease. Although Y. pestis is considered to be an obligate pathogen, the lifestyle of this organism is surprisingly complex. The bacteria are normally transmitted to humans from a flea vector, and Y. pestis has a number of mechanisms which allow survival in the flea. Initially, the bacteria have an intracellular lifestyle in the mammalian host, surviving in macrophages. Later, the bacteria adopt an extracellular lifestyle. These different interactions with different host cell types are regulated by a number of systems, which are not well characterized. The availability of the genome sequence for this pathogen should now allow a systematic dissection of these regulatory systems.

ARE LEUCOCYTOZOON SAKHAROFFI SAMBON AND LEUCOCYTOZOON BERESTNEFFI SAMBON SYNONYMOUS?

1950 ◽  
Vol 28d (1) ◽  
pp. 1-4 ◽  
Author(s):  
A. Murray Fallis
Keyword(s):  
Host Cell ◽  
Cell Nucleus ◽  
Infected Cells ◽  
Host Cell Nucleus

The size of the gametocytes of a leucocytozoon in young crows shows a wide variation in birds obtained in different localities. The host cell nucleus of infected cells may be pushed to one side, almost surround the parasite, or be intermediate between these extremes. Previous descriptions, given by various authors, of Leucocytozoon sakharoffi and L. berestneffi show similar differences in these characters. L. berestneffi is considered therefore to be a synonym of L. sakharoffi.

scholarly journals Barcoded Consortium Infections Resolve Cell Type-Dependent Salmonella enterica Serovar Typhimurium Entry Mechanisms

mBio ◽  
2019 ◽  
Vol 10 (3) ◽  
Author(s):  
Maria Letizia Di Martino ◽  
Viktor Ek ◽  
Wolf-Dietrich Hardt ◽  
Jens Eriksson ◽  
Mikael E. Sellin
Keyword(s):  
Host Cell ◽  
Salmonella Enterica ◽  
Cell Types ◽  
Secretion System ◽  
Host Cells ◽  
Host Cell Invasion ◽  
Cell Type ◽  
Content Type ◽  
Invasion Mechanisms ◽  
Serovar Typhimurium

ABSTRACT Bacterial host cell invasion mechanisms depend on the bacterium’s virulence factors and the properties of the target cell. The enteropathogen Salmonella enterica serovar Typhimurium (S.Tm) invades epithelial cell types in the gut mucosa and a variety of immune cell types at later infection stages. The molecular mechanism(s) of host cell entry has, however, been studied predominantly in epithelial cell lines. S.Tm uses a type three secretion system (TTSS-1) to translocate effectors into the host cell cytosol, thereby sparking actin ruffle-dependent entry. The ruffles also fuel cooperative invasion by bystander bacteria. In addition, several TTSS-1-independent entry mechanisms exist, involving alternative S.Tm virulence factors, or the passive uptake of bacteria by phagocytosis. However, it remains ill-defined how S.Tm invasion mechanisms vary between host cells. Here, we developed an internally controlled and scalable method to map S.Tm invasion mechanisms across host cell types and conditions. The method relies on host cell infections with consortia of chromosomally tagged wild-type and mutant S.Tm strains, where the abundance of each strain can be quantified by qPCR or amplicon sequencing. Using this methodology, we quantified cooccurring TTSS-1-dependent, cooperative, and TTSS-1-independent invasion events in epithelial, monocyte, and macrophage cells. We found S.Tm invasion of epithelial cells and monocytes to proceed by a similar MOI-dependent mix of TTSS-1-dependent and cooperative mechanisms. TTSS-1-independent entry was more frequent in macrophages. Still, TTSS-1-dependent invasion dominated during the first minutes of interaction also with this cell type. Finally, the combined action of the SopB/SopE/SopE2 effectors was sufficient to explain TTSS-1-dependent invasion across both epithelial and phagocytic cells. IMPORTANCE Salmonella enterica serovar Typhimurium (S.Tm) is a widespread and broad-host-spectrum enteropathogen with the capacity to invade diverse cell types. Still, the molecular basis for the host cell invasion process has largely been inferred from studies of a few selected cell lines. Our work resolves the mechanisms that Salmonellae employ to invade prototypical host cell types, i.e., human epithelial, monocyte, and macrophage cells, at a previously unattainable level of temporal and quantitative precision. This highlights efficient bacterium-driven entry into innate immune cells and uncovers a type III secretion system effector module that dominates active bacterial invasion of not only epithelial cells but also monocytes and macrophages. The results are derived from a generalizable method, where we combine barcoding of the bacterial chromosome with mixed consortium infections of cultured host cells. The application of this methodology across bacterial species and infection models will provide a scalable means to address host-pathogen interactions in diverse contexts.

scholarly journals THE CYTONUCLEOPROTEINS OF AMEBAE

1963 ◽  
Vol 19 (3) ◽  
pp. 453-466 ◽  
Author(s):  
Thomas J. Byers ◽  
Dorothy B. Platt ◽  
Lester Goldstein
Keyword(s):  
Host Cell ◽  
Cell Nucleus ◽  
Amoeba Proteus ◽  
Host Cells ◽  
Binucleate Cell ◽  
Donor Nucleus ◽  
Random Manner ◽  
Host Cell Nucleus ◽  
Long Term Behavior

Autoradiographs of whole Amoeba proteus host cells fixed after the implantation of single nuclei from A. proteus donors labeled with any one of 8 different radioactive amino acids showed that the label had become highly concentrated in the host cell nucleus as well as in the donor nucleus and that the cytoplasmic activity was relatively low. When these amebae were sectioned, the radioactivity was found to be homogeneously distributed throughout the nuclei. The effect of unlabeled amino acid "chaser," the solubility of the labeled material, and the long-term behavior of the labeled material gave evidence that the radioactivity was in protein. At equilibrium, the host cell nucleus contained approximately 30 per cent of the radioactivity distributed between the two nuclei. This unequal nuclear distribution is attributed to the presence of two classes of nuclear proteins: a non-migratory one that does not leave the nucleus during interphase, and a migratory one, called cytonucleoprotein, that shuttles between nucleus and cytoplasm in a non-random manner. It is estimated that between 12 per cent and 44 per cent of the cytonucleoproteins are present in the cytoplasm of a binucleate cell at any one moment. Nuclei of Chaos chaos host cells also concentrated label acquired from implanted radioactive A. proteus nuclei.

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