Neuropathogenic Escherichia coli K1 does not exhibit proteolytic activities to exert its pathogenicity.

Junaid Iqbal, Mehak Rajani, Ruqaiyyah Siddiqui, Naveed Ahmed Khan*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)

Abstract

Background
Proteases are well-known virulence factors that promote survival, pathogenesis and immune evasion of many pathogens. Several lines of evidence suggest that the blood–brain barrier permeability is a prerequisite in microbial invasion of the central nervous system. Because proteases are frequently associated with vascular permeability by targeting junctional proteins, here it is hypothesized that neuropathogenic Escherichia coli K1 exhibit proteolytic activities to exert its pathogenicity.

Methods
Zymographic assays were performed using collagen and gelatin as substrates. The lysates of whole E. coli K1 strain E44, or E. coli K-12 strain HB101 were tested for proteolytic activities. The conditioned media were prepared by incubating bacteria in RPMI-1640 in the presence or absence of serum. The cell-free supernatants were collected and tested for proteases in zymography as mentioned above. Additionally, proteolytic degradation of host immune factors was determined by co-incubating conditioned media with albumin/immunoglobulins using protease assays.

Results
When collagen or gelatin were used as substrates in zymographic assays, neither whole bacteria nor conditioned media exhibited proteolytic activities. The conditioned media of neuropathogenic E. coli K1 strain E44, or E. coli K-12 strain HB101 did not affect degradation of albumin and immunoglobulins using protease assays.

Conclusions
Neither zymographic assays nor protease assays detected proteolytic activities in either the whole bacteria or conditioned media of E. coli K1 strain E44 and E. coli K-12 strain HB101. These findings suggest that host cell monolayer disruptions and immune evasion strategies are likely independent of proteolytic activities of neuropathogenic E. coli K1.
Original languageEnglish
Article number8
JournalJournal of Negative Results in BioMedicine
Volume12
DOIs
Publication statusPublished - 1 May 2013

Keywords

  • E. coli K1
  • Protease
  • Collagen
  • Gelatin
  • Zymography
  • BSA
  • IgG
  • BSA and IgG

Fingerprint

Dive into the research topics of 'Neuropathogenic Escherichia coli K1 does not exhibit proteolytic activities to exert its pathogenicity.'. Together they form a unique fingerprint.

Cite this