PubMed Health⌕ Search
Home/Archive/PubMed

PubMed · 2227492

External eye flora as a nutrient source for Acanthamoeba.

D F Larkin·D L Easty
View original source ↗Export metadata ↓

Abstract

Certain bacteria cause excystment of Acanthamoeba from cyst to trophozoite form and are then ingested by migrating trophozoites. We studied the response of Acanthamoeba cysts to inoculation on agar seeded with three types of commensal eye bacteria and Escherichia coli. Amoebae excysted on all bacteria tested, and the migration rate of Acanthamoeba trophozoites on each was compared. Acanthamoeba migrated with equal speed on E. coli and Staphylococcus epidermidis. Migration was observed, but was more slow on Micrococcus and Corynebacterium. Commensal bacteria on the eyelids, conjunctiva and tear film may have a role in pathogenesis of Acanthamoeba keratitis.

Explore related subjects

AcanthamoebaAcanthamoeba KeratitisAnimalsConjunctivaCorynebacteriumEscherichia coliHumansMicrococcusStaphylococcus epidermidisComparative StudyJournal ArticleResearch Support, Non-U.S. Gov't

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

D F Larkin, D L Easty. 1990. External eye flora as a nutrient source for Acanthamoeba.. https://doi.org/10.1007/bf00927262

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

PubMed2022

Comparative genomic and biochemical analyses identify a collagen galactosylhydroxylysyl glucosyltransferase from Acanthamoeba polyphaga mimivirus.

Humans and Acanthamoeba polyphaga mimivirus share numerous homologous genes, including collagens and collagen-modifying enzymes. To explore this homology, we performed a genome-wide comparison between human and mimivirus using DELTA-BLAST (Domain Enhanced Lookup Time Accelerated BLAST) and identified 52 new putative mimiviral proteins that are homologous with human proteins. To gain functional insights into mimiviral proteins, their human protein homologs were organized into Gene Ontology (GO) and REACTOME pathways to build a functional network. Collagen and collagen-modifying enzymes form the largest subnetwork with most nodes. Further analysis of this subnetwork identified a putative collagen glycosyltransferase R699. Protein expression test suggested that R699 is highly expressed in Escherichia coli, unlike the human collagen-modifying enzymes. Enzymatic activity assay and mass spectrometric analyses showed that R699 catalyzes the glucosylation of galactosylhydroxylysine to glucosylgalactosylhydroxylysine on collagen using uridine diphosphate glucose (UDP-glucose) but no other UDP-sugars as a sugar donor, suggesting R699 is a mimiviral collagen galactosylhydroxylysyl glucosyltransferase (GGT). To facilitate further analysis of human and mimiviral homologous proteins, we presented an interactive and searchable genome-wide comparison website for quickly browsing human and Acanthamoeba polyphaga mimivirus homologs, which is available at RRID Resource ID: SCR_022140 or https://guolab.shinyapps.io/app-mimivirus-publication/ .

Acanthamoeba↗
PubMed2007

Intramolecular interaction in the tail of Acanthamoeba myosin IC between the SH3 domain and a putative pleckstrin homology domain.

The 466-aa tail of the heavy chain of Acanthamoeba myosin IC (AMIC) comprises an N-terminal 220-residue basic region (BR) followed by a 56-residue Gly/Pro/Ala-rich region (GPA1), a 55-residue Src homology 3 (SH3) domain, and a C-terminal 135-residue Gly/Pro/Ala-rich region (GPA2). Cryo-electron microscopy of AMIC had shown previously that the AMIC tail is folded back on itself, suggesting the possibility of interactions between its N- and C-terminal regions. We now show specific differences between the NMR spectrum of bacterially expressed full-length tail and the sum of the spectra of individually expressed BR and GPA1-SH3-GPA2 (GSG) regions. These results are indicative of interactions between the two subdomains in the full-length tail. From the NMR data, we could assign many of the residues in BR and GSG that are involved in these interactions. By combining homology modeling with the NMR data, we identify a putative pleckstrin homology (PH) domain within BR, and show that the PH domain interacts with the SH3 domain.

Acanthamoeba↗
PubMed2007

Legionella impletisoli sp. nov. and Legionella yabuuchiae sp. nov., isolated from soils contaminated with industrial wastes in Japan.

In this study, we tried to isolate legionellae from nine Legionella DNA-positive soil samples collected from four different sites contaminated with industrial wastes in Japan. Using culture methods with or without Acanthamoeba culbertsoni, a total of 22 isolates of legionellae were obtained from five of the nine samples. Identification of species and/or serogroups (SGs), performed by DNA-DNA hybridization and agglutination tests, revealed that the 22 isolates consisted of ten isolates of Legionella pneumophila including five SGs, five Legionella feeleii, and one each of Legionella dumoffii, Legionella longbeachae, and Legionella jamestownensis. The species of the remaining four isolates (strains OA1-1, -2, -3, and -4) could not be determined, suggesting that these isolates may belong to new species. The 16S rDNA sequences (1476-1488bp) of the isolates had similarities of less than 95.0% compared to other Legionella species. A phylogenetic tree created by analysis of the 16S rRNA (1270bp) genes demonstrated that the isolates formed distinct clusters within the genus Legionella. Quantitative DNA-DNA hybridization tests on the OA1 strains indicated that OA1-1 should be categorized as a new taxon, whereas OA1-2, -3, and -4 were also genetically independent in another taxon. Based on the evaluated phenotypic and phylogenetic characteristics, it is proposed that one of these isolates from the soils, OA1-1, be classified as a novel species, Legionella impletisoli sp. nov.; the type strain is strain OA1-1(T) (=JCM 13919(T)=DSMZ 18493(T)). The remaining three isolates belong to another novel Legionella species, Legionella yabuuchiae sp. nov.; the type strain is strain OA1-2(T) (=JCM 14148(T)=DSMZ 18492(T)). This is the first report on the isolation of legionellae from soils contaminated with industrial wastes.

Acanthamoeba↗