scholarly journals Huge and variable diversity of episymbiotic CPR bacteria and DPANN archaea in groundwater ecosystems

2020 ◽  
Author(s):  
Christine He ◽  
Ray Keren ◽  
Michael Whittaker ◽  
Ibrahim F. Farag ◽  
Jennifer Doudna ◽  
...  
Keyword(s):  
Cell Attachment ◽  
Taxonomic Diversity ◽  
Host Cells ◽  
Groundwater Aquifers ◽  
Groundwater Ecosystems ◽  
Genomic Analyses ◽  
Host Cell Attachment ◽  
Health Relevance ◽  
Candidate Phyla Radiation

AbstractCandidate Phyla Radiation (CPR) bacteria and DPANN archaea are uncultivated, small-celled symbionts often detected in groundwater. However, variations in CPR/DPANN organism abundance, distribution, taxonomic diversity, and degree/nature of host association with groundwater chemistry remain understudied. Here, we performed genome-resolved metagenomic characterization of one agriculturally-impacted and seven pristine groundwater microbial communities in California, recovering 746 dereplicated CPR and DPANN genomes. Our finding of up to 31% CPR bacteria and 4% DPANN archaea in the pristine sites, which serve as local sources of drinking water, may hold health relevance, given growing awareness of the presence of CPR/DPANN organisms in human microbiomes and their association with disease. There is little species-level genome overlap across groundwater sites, indicating that CPR and DPANN communities are highly differentiated according to host populations and physicochemical conditions. Cryo-TEM imaging and genomic analyses indicate that CPR growth may be stimulated by attachment to the surface of host cells, and identified CPR and DPANN lineages with particularly prevalent and/or resilient host cell attachment. These results establish the huge but site-specific diversity of CPR bacteria and DPANN archaea coexisting with diverse hosts in groundwater aquifers, and raise important questions about potential impacts on human health.

scholarly journals Genome-resolved metagenomics reveals site-specific diversity of episymbiotic CPR bacteria and DPANN archaea in groundwater ecosystems

2021 ◽  
Vol 6 (3) ◽  
pp. 354-365 ◽  
Author(s):  
Christine He ◽  
Ray Keren ◽  
Michael L. Whittaker ◽  
Ibrahim F. Farag ◽  
Jennifer A. Doudna ◽  
...  
Keyword(s):  
Drinking Water ◽  
Taxonomic Diversity ◽  
Host Cells ◽  
Microscopy Imaging ◽  
Site Specific ◽  
Groundwater Aquifers ◽  
Transmission Electron ◽  
Groundwater Ecosystems ◽  
Genomic Analyses ◽  
Candidate Phyla Radiation

AbstractCandidate phyla radiation (CPR) bacteria and DPANN archaea are unisolated, small-celled symbionts that are often detected in groundwater. The effects of groundwater geochemistry on the abundance, distribution, taxonomic diversity and host association of CPR bacteria and DPANN archaea has not been studied. Here, we performed genome-resolved metagenomic analysis of one agricultural and seven pristine groundwater microbial communities and recovered 746 CPR and DPANN genomes in total. The pristine sites, which serve as local sources of drinking water, contained up to 31% CPR bacteria and 4% DPANN archaea. We observed little species-level overlap of metagenome-assembled genomes (MAGs) across the groundwater sites, indicating that CPR and DPANN communities may be differentiated according to physicochemical conditions and host populations. Cryogenic transmission electron microscopy imaging and genomic analyses enabled us to identify CPR and DPANN lineages that reproducibly attach to host cells and showed that the growth of CPR bacteria seems to be stimulated by attachment to host-cell surfaces. Our analysis reveals site-specific diversity of CPR bacteria and DPANN archaea that coexist with diverse hosts in groundwater aquifers. Given that CPR and DPANN organisms have been identified in human microbiomes and their presence is correlated with diseases such as periodontitis, our findings are relevant to considerations of drinking water quality and human health.

scholarly journals Complementation of the fadA Mutation in Fusobacterium nucleatum Demonstrates that the Surface-Exposed Adhesin Promotes Cellular Invasion and Placental Colonization

2009 ◽  
Vol 77 (7) ◽  
pp. 3075-3079 ◽  
Author(s):  
Akihiko Ikegami ◽  
Peter Chung ◽  
Yiping W. Han
Keyword(s):  
Host Cell ◽  
Cell Attachment ◽  
Adverse Pregnancy Outcome ◽  
Fusobacterium Nucleatum ◽  
Host Cells ◽  
Mouse Placenta ◽  
Host Cell Attachment ◽  
Adverse Pregnancy

ABSTRACT Fusobacterium nucleatum is a gram-negative oral anaerobe implicated in periodontal disease and adverse pregnancy outcome. The organism colonizes the mouse placenta, causing localized infection and inflammation. The mechanism of placental colonization has not been elucidated. Previous studies identified a novel adhesin from F. nucleatum, FadA, as being involved in the attachment and invasion of host cells. The fadA deletion mutant F. nucleatum 12230 US1 was defective in host cell attachment and invasion in vitro, but it also exhibited pleiotropic effects with altered cell morphology and growth rate. In this study, a fadA-complementing clone, F. nucleatum 12230 USF81, was constructed. The expression of FadA on USF81 was confirmed by Western blotting and immunofluorescent labeling. USF81 restored host cell attachment and invasion activities. The ability of F. nucleatum 12230, US1, and USF81 to colonize the mouse placenta was examined. US1 was severely defective in placental colonization compared to the wild type and USF81. Thus, FadA plays an important role in F. nucleatum colonization in vivo. These results also represent the first complementation studies for F. nucleatum. FadA may be a therapeutic target for preventing F. nucleatum colonization of the host.

scholarly journals Toxoplasma gondii Uses Sulfated Proteoglycans for Substrate and Host Cell Attachment

2000 ◽  
Vol 68 (7) ◽  
pp. 4005-4011 ◽  
Author(s):  
Vern B. Carruthers ◽  
Sebastian Håkansson ◽  
Olivia K. Giddings ◽  
L. David Sibley
Keyword(s):  
Toxoplasma Gondii ◽  
Cell Attachment ◽  
Gliding Motility ◽  
Host Cells ◽  
Cell Recognition ◽  
Intracellular Parasite ◽  
Chondroitin Sulfates ◽  
Host Cell Attachment ◽  
Mutant Host ◽  
Sulfated Proteoglycans

ABSTRACT Toxoplasma gondii is an obligate intracellular parasite that actively invades a wide variety of vertebrate cells, although the basis of this pervasive cell recognition is not understood. We demonstrate here that binding to the substratum and to host cells is partially mediated by interaction with sulfated glycosaminoglycans (GAGs). Addition of excess soluble GAGs blocked parasite attachment to serum-coated glass, thereby preventing gliding motility of extracellular parasites. Similarly, excess soluble GAGs decreased the attachment of parasites to human host cells from a variety of lineages, including monocytic, fibroblast, endothelial, epithelial, and macrophage cells. The inhibition of parasite attachment by GAGs was observed with heparin and heparan sulfate and also with chondroitin sulfates, indicating that the ligands for attachment are capable of recognizing a broad range of GAGs. The importance of sulfated proteoglycan recognition was further supported by the demonstration that GAG-deficient mutant host cells, and wild-type cells treated enzymatically to remove GAGs, were partially resistant to parasite invasion. Collectively, these studies reveal that sulfated proteoglycans are one determinant used for substrate and cell recognition by Toxoplasma. The widespread distribution of these receptors may contribute to the broad host and tissue ranges of this highly successful intracellular parasite.

scholarly journals Structural characterization of a novel subfamily of leucine-rich repeat proteins from the human pathogenLeptospira interrogans

2015 ◽  
Vol 71 (6) ◽  
pp. 1351-1359 ◽  
Author(s):  
Isabelle Miras ◽  
Frederick Saul ◽  
Mireille Nowakowski ◽  
Patrick Weber ◽  
Ahmed Haouz ◽  
...  
Keyword(s):  
Pathogenic Bacteria ◽  
Cell Attachment ◽  
Leucine Rich Repeat ◽  
Host Proteins ◽  
Repeat Proteins ◽  
Number Of Genes ◽  
Genes Encoding ◽  
Host Cell Attachment ◽  
Insight Into

PathogenicLeptospiraspp. are the agents of leptospirosis, an emerging zoonotic disease. Analyses ofLeptospiragenomes have shown that the pathogenic leptospires (but not the saprophytes) possess a large number of genes encoding proteins containing leucine-rich repeat (LRR) domains. In other pathogenic bacteria, proteins with LRR domains have been shown to be involved in mediating host-cell attachment and invasion, but their functions remain unknown inLeptospira. To gain insight into the potential function of leptospiral LRR proteins, the crystal structures of four LRR proteins that represent a novel subfamily with consecutive stretches of a 23-amino-acid LRR repeat motif have been solved. The four proteins analyzed adopt the characteristic α/β-solenoid horseshoe fold. The exposed residues of the inner concave surfaces of the solenoid, which constitute a putative functional binding site, are not conserved. The various leptospiral LRR proteins could therefore recognize distinct structural motifs of different host proteins and thus serve separate and complementary functions in the physiology of these bacteria.

scholarly journals O-fucosylation of thrombospondin-like repeats is required for processing of MIC2 and for efficient host cell invasion by Toxoplasma gondii tachyzoites

2018 ◽  
Author(s):  
Giulia Bandini ◽  
Deborah R. Leon ◽  
Carolin M. Hoppe ◽  
Yue Zhang ◽  
Carolina Agop-Nersesian ◽  
...  
Keyword(s):  
Toxoplasma Gondii ◽  
Host Cell ◽  
Secretory Pathway ◽  
Cell Attachment ◽  
Host Cells ◽  
Type I ◽  
Human Foreskin Fibroblasts ◽  
Genes Encoding ◽  
Host Cell Attachment ◽  
Glycosylation Pathway

AbstractToxoplasma gondii is an intracellular parasite that causes disseminated infections which can lead to neurological damage in fetuses and immunocompromised individuals. Microneme protein 2 (MIC2)2, a member of the thrombospondin-related anonymous protein (TRAP) family, is a secreted protein important for motility, host cell attachment, invasion, and egress. MIC2 contains six thrombospondin type I repeats (TSRs) that are modified by C-mannose and O-fucose in Plasmodium spp. and mammals.Here we used mass spectrometry to show that the four TSRs in T. gondii MIC2 with protein O-fucosyltransferase 2 (POFUT2) acceptor sites are modified by a dHexHex disaccharide, while Trp residues within three TSRs are also modified with C-mannose. Disruption of genes encoding either pofut2 or nucleotide sugar transporter 2 (nst2), the putative GDP-fucose transporter, results in loss of MIC2 O-fucosylation, as detected by an antibody against the GlcFuc disaccharide, and markedly reduced cellular levels of MIC2. Furthermore, in 10-15% of the Δpofut2 or Δnst2 vacuoles, MIC2 accumulates earlier in the secretory pathway rather than localizing to micronemes. Dissemination of tachyzoites in human foreskin fibroblasts is reduced in these knockouts, which both show defects in attachment to and invasion of host cells comparable to the phenotype observed in the Βmic2.These results, which show O-fucosylation of TSRs is required for efficient processing of MIC2 and for normal parasite invasion, are consistent with the recent demonstration that P. falciparum Δpofut2 has decreased virulence and support a conserved role for this glycosylation pathway in quality control of TSR-containing proteins in eukaryotes.

scholarly journals Acquisition of the arginine deiminase system benefits epiparasitic Saccharibacteria and their host bacteria in a mammalian niche environment

2022 ◽  
Vol 119 (2) ◽  
pp. e2114909119
Author(s):  
Jing Tian ◽  
Daniel R. Utter ◽  
Lujia Cen ◽  
Pu-Ting Dong ◽  
Wenyuan Shi ◽  
...  
Keyword(s):  
Acid Stress ◽  
Arginine Deiminase ◽  
Oral Microbiome ◽  
Comparative Genomic ◽  
Host Bacterium ◽  
Mutualistic Interaction ◽  
Genomic Analyses ◽  
Selection For ◽  
Candidate Phyla Radiation

Saccharibacteria are a group of widespread and genetically diverse ultrasmall bacteria with highly reduced genomes that belong to the Candidate Phyla Radiation. Comparative genomic analyses suggest convergent evolution of key functions enabling the adaptation of environmental Saccharibacteria to mammalian microbiomes. Currently, our understanding of this environment-to-mammal niche transition within Saccharibacteria and their obligate episymbiotic association with host bacteria is limited. Here, we identified a complete arginine deiminase system (ADS), found in further genome streamlined mammal-associated Saccharibacteria but missing in their environmental counterparts, suggesting acquisition during environment-to-mammal niche transition. Using TM7x, the first cultured Saccharibacteria strain from the human oral microbiome and its host bacterium Actinomyces odontolyticus, we experimentally tested the function and impact of the ADS. We demonstrated that by catabolizing arginine and generating adenosine triphosphate, the ADS allows metabolically restrained TM7x to maintain higher viability and infectivity when disassociated from the host bacterium. Furthermore, the ADS protects TM7x and its host bacterium from acid stress, a condition frequently encountered within the human oral cavity due to bacterial metabolism of dietary carbohydrates. Intriguingly, with a restricted host range, TM7x forms obligate associations with Actinomyces spp. lacking the ADS but not those carrying the ADS, suggesting the acquired ADS may also contribute to partner selection for cooperative episymbiosis within a mammalian microbiome. These data present experimental characterization of a mutualistic interaction between TM7x and their host bacteria, and illustrate the benefits of acquiring a novel pathway in the transition of Saccharibacteria to mammalian microbiomes.

scholarly journals Reovirus Cell Entry Requires Functional Microtubules

mBio ◽  
2013 ◽  
Vol 4 (4) ◽  
Author(s):  
Bernardo A. Mainou ◽  
Paula F. Zamora ◽  
Alison W. Ashbrook ◽  
Daniel C. Dorset ◽  
Kwang S. Kim ◽  
...  
Keyword(s):  
Cell Attachment ◽  
Endocytic Pathway ◽  
Cell Entry ◽  
Host Cells ◽  
Microtubule Inhibitors ◽  
Viral Particles ◽  
Microtubule Motor ◽  
Cellular Mediators ◽  
Rapid Characterization

ABSTRACTMammalian reovirus binds to cell-surface glycans and junctional adhesion molecule A and enters cells by receptor-mediated endocytosis in a process dependent on β1 integrin. Within the endocytic compartment, reovirus undergoes stepwise disassembly, allowing release of the transcriptionally active viral core into the cytoplasm. To identify cellular mediators of reovirus infectivity, we screened a library of small-molecule inhibitors for the capacity to block virus-induced cytotoxicity. In this screen, reovirus-induced cell killing was dampened by several compounds known to impair microtubule dynamics. Microtubule inhibitors were assessed for blockade of various stages of the reovirus life cycle. While these drugs did not alter reovirus cell attachment or internalization, microtubule inhibitors diminished viral disassembly kinetics with a concomitant decrease in infectivity. Reovirus virions colocalize with microtubules and microtubule motor dynein 1 during cell entry, and depolymerization of microtubules results in intracellular aggregation of viral particles. These data indicate that functional microtubules are required for proper sorting of reovirus virions following internalization and point to a new drug target for pathogens that use the endocytic pathway to invade host cells.IMPORTANCEScreening libraries of well-characterized drugs for antiviral activity enables the rapid characterization of host processes required for viral infectivity and provides new therapeutic applications for established pharmaceuticals. Our finding that microtubule-inhibiting drugs impair reovirus infection identifies a new cell-based antiviral target.

scholarly journals Characterization of Lassa Virus Cell Entry and Neutralization with Lassa Virus Pseudoparticles

2009 ◽  
Vol 83 (7) ◽  
pp. 3228-3237 ◽  
Author(s):  
François-Loic Cosset ◽  
Philippe Marianneau ◽  
Geraldine Verney ◽  
Fabrice Gallais ◽  
Noel Tordo ◽  
...  
Keyword(s):  
Immune Response ◽  
Humoral Immune Response ◽  
Neutralizing Antibodies ◽  
Cell Attachment ◽  
Low Ph ◽  
Cell Entry ◽  
Lassa Virus ◽  
Ph Optimum ◽  
Humoral Immune

ABSTRACT The cell entry and humoral immune response of the human pathogen Lassa virus (LV), a biosafety level 4 (BSL4) Old World arenavirus, are not well characterized. LV pseudoparticles (LVpp) are a surrogate model system that has been used to decipher factors and routes involved in LV cell entry under BSL2 conditions. Here, we describe LVpp, which are highly infectious, with titers approaching those obtained with pseudoparticles displaying G protein of vesicular stomatitis virus and their the use for the characterization of LV cell entry and neutralization. Upon cell attachment, LVpp utilize endocytic vesicles for cell entry as described for many pH-dependent viruses. However, the fusion of the LV glycoproteins is activated at unusually low pH values, with optimal fusion occurring between pH 4.5 and 3, a pH range at which fusion characteristics of viral glycoproteins have so far remained largely unexplored. Consistent with a shifted pH optimum for fusion activation, we found wild-type LV and LVpp to display a remarkable resistance to exposure to low pH. Finally, LVpp allow the fast and quantifiable detection of neutralizing antibodies in human and animal sera and will thus facilitate the study of the humoral immune response in LV infections.

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