Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0022568 (keratitis)
 5,133 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Free-living and parasitic protozoa are known to harbor a variety of endosymbiotic bacteria, although the roles such endosymbionts play in host survival, infectivity, and invasiveness are unclear. We have identified the presence of intracellular bacteria in 14 of 57 (24%) axenically grown Acanthamoeba isolates examined. These organisms are gram negative and non-acid fast, and they cannot be cultured by routine methodologies, although electron microscopy reveals evidence for multiplication within the amoebic cytoplasm. Examination for Legionella spp. with culture and nucleic acid probes has proven unsuccessful. We conclude that these bacteria are endosymbionts which have an obligate need to multiply within their amoebic hosts. Rod-shaped bacteria were identified in 5 of 23 clinical Acanthamoeba isolates (3 of 19 corneal isolates and 2 of 4 contact lens isolates), 4 of 25 environmental Acanthamoeba isolates, and 2 of 9 American Type Culture Collection Acanthamoeba isolates (ATCC 30868 and ATCC 30871) previously unrecognized as having endosymbionts. Coccus-shaped bacteria were present in one clinical (corneal) isolate and two environmental isolates. There was no statistical difference (P > 0.8) between the numbers of endosymbiont strains originating from clinical (26% positive) and environmental (24% positive) amoebic isolates, suggesting that the presence alone of these bacteria does not enhance amoebic infectivity. Rods and cocci were found in both clinical and environmental isolates from different geographical areas (Seattle, Wash., and Portland, Oreg.), demonstrating their widespread occurrence in nature. Our findings suggest that endosymbiosis occurs commonly among members of the family Acanthamoebidae and that the endosymbionts comprise a diverse taxonomic assemblage. The role such endosymbionts may play in pathogenesis remains unknown, although a variety of exogenous bacteria have been implicated in the development of amoebic keratitis, warranting further evaluation.
 ...
PMID:Occurrence of bacterial endosymbionts in Acanthamoeba spp. isolated from corneal and environmental specimens and contact lenses. 850 Dec 12

Fungal keratitis is a serious, potentially sight-threatening corneal infection that is more prevalent in the tropical parts of the world including India, and A. flavus and Fusarium solani are the predominant etiological agents. The surface of fungal conidia is covered by hydrophobin family proteins, effectively masking the conidial antigens from immune cells. In this study, we report that the outer cell wall layer of A. flavus conidia contain Rod A as well as other hydrophobins, which could be extracted by formic acid. Analysis of these surface proteins by mass spectrometry showed the presence of rodlet forming hydrophobins and other membrane and antigenic proteins. Our analysis revealed that Rod A existed as two proteoforms on the conidial surface. These proteoforms were separated using polyacrylamide gel electrophoresis and the amino acid sequence of these proteoforms was determined by high resolution mass spectrometry. PCR analysis of the mRNA encoding the Rod A showed the retention of intron one, which results in the formation of a truncated proteoform two. This is the first report in which the presence of RodA and its proteoforms and their mechanism of formation has been demonstrated in the corneal pathogenic fungus A. flavus. SIGNIFICANCE: A. flavus is a common fungal pathogen in tropical countries playing a predominant role in causing mycotic keratitis in humans. Surface of fungal conidia is immunologically inert primarily due to the hydrophobin family proteins forming a rodlet layer and masking the conidia from immune cells. In this study we demonstrated the existence two proteoforms of RodA/hydrophobin A and intron retention is shown to be responsible for the formation of one of the proteoforms. In addition, the spore surface proteins of A.flavus corneal isolates and saprophyte are distinctly different, which indicate the spore surface protein profile is ecotype specific. This is the first report showing the presence of two proteoforms of RodA on A.flavus conidial surface and demonstration of the mechanism of formation of the proteoforms.
 ...
PMID:Identification of the proteoforms of surface localized Rod A of Aspergillus flavus and determination of the mechanism of proteoform generation. 3055 65

Fungal keratitis is a major sight-threatening corneal infection: and mycotic keratitis is more common in tropical parts of the world including India. Aspergillus flavus and Fusarium are the predominant causative agents of corneal infection. We extracted conidial surface proteins of A. flavus from saprophyte and clinical isolates and analyzed the proteins using high resolution mass spectrometry. The data revealed ecotype specific alteration in surface proteome since the proteome profile of the clinical isolates and saprophyte showed significant differences. Detailed examination of the mass spec data of RodA proteins extracted from polyacrylamide gels revealed the presence of two proteoforms of this protein. We also identified the mechanism of formation of these two isoforms. Detailed analysis of this data and the conclusions derived are described in the article, "Identification of the proteoforms of surface localized Rod A of A. flavus and determination of the mechanism of proteoform generation" [1].
 ...
PMID:Dataset for the spore surface proteome and hydrophobin A/RodA proteoforms of A.flavus. 3137 61