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Bioscience Methods
BM 2011, Vo.2, No.4, 21-30
http://bm.sophiapublisher.com
- 26 -
Table 3 Effects of various monosaccharides on the adhesion of
P. aeruginosa
(Paer
6294
-
GFP) to human corneal epithelial cells
grown in cell culture
Monosaccharide
Concentration (mmol/L)
Number of adhering bacteria×105
Inhibition (%)
D-galactose (Gal)
0.00
11.5 ± 0.4
-
6.25
7.4 ± 2.4
35.7
12.50
6.0 ± 0.8
47.8
25.00
7.4 ± 0.6
35.7
N-Acetylgalactosamine
0.00
11.5 ± 0.4
-
(GalNAc)
6.25
8.0 ± 0.8
30.4
12.50
6.5 ± 0.1
43.5
25.00
6.5 ± 1.1
43.5
D-glucose (Glc)
0.00
11.5 ± 0.4
-
6.25
11.8 ± 0.4
0.0
12.50
11.6 ± 0.1
0.0
25.00
11.5 ± 0.5
0.0
ratio of 2:2:2:1:1. The results are similar to the amino
acid and major monosaccharide constituents of
Q-mucin (Masuda et al., 2007). The presence of minor
amounts of mannose and sialic acid in
C. mosaicus
bell mucin (Table 1) indicated the existence of more
complex O-linked glycans and/or N-linked glycans. In
contrast, the oligosaccharides of Q-mucin contained
no sialic acid (Uzawa et al., 2009). Urai et al (Urai et
al., 2009) has further characterised the glycan
components of Q-mucin and found a unique
monosaccharide, 2
-
amino-ethyl phosphonate (2AEP)
-
(6)
-
GalNAc, using a combination of NMR and
ESI-MS/MS. This unique O-glycan was not detected
by us. However, the ester bond of 2AEP
-
(6)
-
GalNAc
could not be cleaved by hydrazidation or the
hydrolysis method that we used in our mono-
saccharide compositional analysis. The elution
property (e.g. retention time on HPLC) of this new
2AEP
-
(6)
-
GalNAc is very similar to that of GlcNAc.
Therefore it is possible that some or all of the bell
mucin GlcNAc may represent this new structure.
C. mosaicus
bell mucin stained strongly with Alcian
blue which is sensitive to acidic sulfonic and carboxy
groups. The presence of sialic acid is consistent with
this staining pattern. Further research is needed to cha-
racterise the full spectrum of glycans on
C. mosaicus
bell mucin.
Jellyfish mucins have high amino acid compositional
and sequence similarity to the human MUC5AC
mucin (Masuda et al., 2007), although they appear to
contain no (or minimal) Ser residues in any repeat
structure. MUC5AC comprises the majority of mucins
in the conjunctiva tissue and secretion and in human
tear fluid (Argüeso et al., 2002; McKenzie et al., 2000;
Jumblatt et al., 1999). MUC5AC are present at much
higher levels in human conjunctiva epithelia than
those for the secreted mucin MUC2 (McKenzie et al.,
2000), and it may be implicated in common eye
disorders. MUC5AC mRNA expression in eyes of
patients with atopic keratoconjunctivitis (Dogru et al.,
2008) and in tears of patients with Sjogren syndrome
(Argüeso et al., 2002) was reduced compared with
those of healthy individuals. In addition, MUC5AC
mRNA production is up-regulated in response to
P. aeruginosa
and its exoproducts (Li et al., 1998).
The current hypothesis regarding mucin function and
tear film structure is that the secreted mucins, such as
MUC5AC, are part of the “first-line defence” barrier
that prevents pathogens from traversing the mucosal
barrier (Davidson and Kuonen 2004; Mantelli and
Argüeso 2008). Our study has demonstrated that
jellyfish mucins possess potential binding sites for
P. aeruginosa
and prevent its binding to epithelial
cells grown in cell culture. There has been increasing
interest directed toward the protective properties of