Porcine epidemic diarrhea virus (PEDV) infects piglets and causes serious diarrhea as well as vomiting, dehydration, and death. The trimeric S protein plays a crucial role in the induction of neutralizing antibodies, and many neutralizing monoclonal antibodies (mAbs) against PEDV S protein have been developed. However, these mAbs exclusively target the S1 protein. In this study, we obtained a neutralizing mAb, 5F7, against the S2 protein of PEDV, and this mAb could neutralize new variant genotype 2 PEDV strains (LNCT2), as well as a genotype 1 PEDV strain (CV777), in vitro. The core sequence of the epitope was found in amino acid sequence 1261 aa~1337 aa. These findings confirm that the S2 protein possessed neutralizing epitopes and provided knowledge to aid further research on this virus. 相似文献
The SARS-CoV-2 virus that causes COVID-19 is a global health issue. The spread of the virus has resulted in seven million deaths to date. The emergence of new viral strains highlights the importance of continuous surveillance of the SARS-CoV-2 virus by using timely and accurate diagnostic tools. Here, we used a stable cyclic peptide scaffolds to present antigenic sequences derived from the spike protein that are reactive to SARS-CoV-2 antibodies. Using peptide sequences from different domains of SARS-CoV-2 spike proteins, we grafted epitopes on the peptide scaffold sunflower trypsin inhibitor 1 (SFTI-1). These scaffold peptides were then used to develop an ELISA to detect SARS-CoV-2 antibodies in serum. We show that displaying epitopes on the scaffold improves reactivity overall. One of the scaffold peptides (S2_1146-1161_c) has reactivity equal to that of commercial assays, and shows diagnostic potential. 相似文献
Rhinoviruses (RVs) are major causes of the common cold, but they can also trigger exacerbations of asthma. More than 160 different RV strains exist and can be classified into three genetic species (RV-A, RV-B and RV-C) which bind to different receptors on human cells including intracellular adhesion molecule 1 (ICAM-1), the low-density lipoprotein receptor (LDLR) or the cadherin-related family member 3 (CDHR3). Epitopes located in the RV capsid have mainly been determined for RV2, a minor-group RV-A strain binding to LDLR, and for RV14, a major-group RV-B strain binding to ICAM-1. In order to study epitopes involved in the neutralization of RV89, an ICAM-1-binding RV-A strain which is highly different from RV2 and RV14 in terms of receptor specificity and sequence, respectively, we analyzed the specificity and epitopes of a highly neutralizing antiserum using recombinantly produced RV89 capsid proteins (VP1, VP2, VP3 and VP4), recombinant fragments and synthetic overlapping peptides thereof. We found that the antiserum which neutralized in vitro RV89 infection up to a dilution of 1:24,000 reacted with the capsid proteins VP1 and VP2 but not with VP3 and VP4. The neutralizing antibodies recognized recombinant fragments comprising approximately 100 amino acids of the N- and C-terminus of VP1 and the middle part of VP2, in particular, three peptides which, according to molecular modeling based on the three-dimensional structure of RV16, were surface-exposed on the viral capsid. Two recombinant fusion proteins containing the identified peptides fused to hepatitis B (HBV)-derived preS as a carrier protein induced upon immunization of rabbits antibodies capable of neutralizing in vitro RV89 infections. Interestingly, the virus-neutralizing epitopes determined for RV89 corresponded to those determined for minor-group RV2 binding to LDL and major-group RV14 belonging to the RV-B species, which are highly different from RV89. Our results indicate that highly different RV strains, even when reacting with different receptors, seem to engage similar parts of their capsid in the infection process. These results may be important for the design of active and passive immunization strategies for RV. 相似文献
Over the last decade the seroprevalence of immunoglobulin (IgG) anti hepatitis E virus (HEV) has been increasing in European countries and shows significant variability among different geographical areas. In this review, we describe the serological data concerning the general population and risk groups in different European countries. Anti-HEV antibody prevalence ranged from 1.3% (blood donors in Italy) to 52% (blood donors in France). Various studies performed on risk groups in Denmark, Moldova and Sweden revealed that swine farmers have a high seroprevalence of HEV IgG (range 13%–51.1%), confirming that pigs represent an important risk factor in HEV infection in humans. Subtypes 3e,f are the main genotypes detected in the European population. Sporadic cases of autochthonous genotype 4 have been described in Spain, France, and Italy. Although most HEV infections are subclinical, in immune-suppressed and transplant patients they could provoke chronic infection. Fulminant hepatitis has rarely been observed and it was related to genotype 3. Interferon and ribavirin treatment was seen to represent the most promising therapy. 相似文献
Biotinylated mono‐ and biantennary di‐/trisaccharides were synthesized to evaluate their ability to capture E. coli strains that express pilus types with different receptor specificities. The synthesized biotinylated di‐/trisaccharides contain Galα(1→4)Gal, Galα(1→4)GalNHAc, GalNHAcα(1→4)Gal, Galα(1→4)Galβ(1→4)Glc and GalNHAcα(1→4)Galβ(1→4)Glc as carbohydrate epitopes. These biotinylated oligosaccharides were immobilized on streptavidin‐coated magnetic beads, and incubated with different strains of live E. coli. Capturing ability was assessed by using a luciferase assay that detects bacterial ATP. The trisaccharides containing Galα(1→4)Galβ(1→4)Glc and the disaccharides containing Galα(1→4)Gal as the epitopes exhibited strong capturing ability for uropathogenic E. coli strains with the pap pilus genotype, including CFT073, J96 and J96 pilE. The same ligands failed to capture E. coli strains with fim, prs, or foc genotypes. Uropathogenic CFT073 was also captured moderately by biantennary disaccharides containing a GalNHAc moiety at the reducing end; however, other saccharides containing GalNHAc at the nonreducing end did not capture the CFT073 strain. These synthetic glycoconjugates could potentially be adapted as rapid diagnostic agents to differentiate between different E. coli pathovars. 相似文献
Disarmed forces : Inhibition of the central virulence regulator ClpP by structurally refined β‐lactones resulted in dramatically reduced production of devastating virulence factors, including pyrogenic toxin superantigens derived from pathogenic multiresistant Staphylococcus aureus strains. Targeting of this virulence regulator could present an attractive strategy for neutralizing the harmful effects of bacterial pathogens, and help the host immune response to eliminate the disarmed bacteria.
Vertical electrolysers with a narrow electrode gap are used to produce gases, for example, chlorine, hydrogen and oxygen. The gas voidage in the solution increases with increasing height in the electrolyser and consequently the current density is expected to decrease with increasing height. Current distribution experiments were carried out in an undivided cell with two electrodes each consisting of 20 equal segments or with a segmented electrode and a one-plate electrode. It was found that for a bubbly flow the current density decreases linearly with increasing height in the cell. The current distribution factor increases with increasing average current density, decreasing volumetric flow rate of liquid and decreasing distance between the anode and the cathode. Moreover, it is concluded that the change in the electrode surface area remaining free of bubbles with increasing height has practically no effect on the current distribution factor.Notation
Ae
electrode surface area (m2)
-
Ae,s
surface area of an electrode segment (m2)
-
Ae, 1–19
total electrode surface area for the segments from 1 to 19 inclusive (m2)
-
Ae,a
anode surface area (m2)
-
Ae,a,hAe,a remaining free of bubbles (m2)
-
Ae,e
cathode surface area (m2)
-
Ae,c,hAe,c remaining free of bubbles (m2)
-
a1
parameter in Equation 7 (A–1)
-
B
current distribution factor
-
BrB in reverse position of the cell
-
BsB in standard position of cell
-
ba
Tafel slope for the anodic reaction (V)
-
bc
Tafel slope for the cathodic reaction (V)
-
d
distance (m)
-
dac
distance between the anode and the cathode (m)
-
dwm
distance between the working electrode and an imaginary membrane (m) (dwm=0.5dwt=0.5dac)
-
dwt
distance between the working and the counter electrode (m)
-
F
Faraday constant (C mol–1)
-
h
height from the leading edge of the working electrode corresponding to height in the cell (m)
-
he
distance from the bottom to the top of the working electrode (m)
-
I
current (A)
-
Is
current for a segment (A)
-
I20
current for segment pair 20 (A)
-
I1–19
total current for the segment pairs from 1 to 19 inclusive (A)
-
i
current density (A m–2)
-
iav
average current density of working electrode (A m–2)
-
ib
current density at the bottom edge of the working electrode (A m–2)
-
i0
exchange current density (A m–2)
-
i0,ai0 for anode reaction (A m–2)
-
il
current density at the top edge of the working electrode (A m–2)
-
n1
parameter in Equation 15
-
ns
number of a pair of segments of the segmented electrodes from their leading edges
-
Qg
volumetric rate of gas saturated with water vapour (m3 s–1)
-
Q1
volumetric rate of liquid (m3 s–1)
-
R
resistance of solution ()
-
R20
resistance of solution between the top segments of the working and the counter electrode ()
-
Rp
resistance of bubble-free solution ()
-
Rp,20Rp for segment pair 20 ()
-
rs
reduced specific surface resistivity
-
rs,0rs ath=0
-
rs,20rs for segment pair 20
-
rs,rs for uniform distribution of bubbles between both the segments of a pair
-
rs,,20rs, for segment pair 20
-
T
temperature (K)
-
U
cell voltage (V)
-
Ur
reversible cell voltage (V)
-
v1
linear velocity of liquid (m s–1)
-
v1,0v1 through interelectrode gap at the leading edges of both electrodes (m s–1)
-
x
distance from the electrode surface (m)
-
gas volumetric flow ratio
- 20
at segment pair 20
-
specific surface resistivity ( m2)
- t
at top of electrode ( m2)
- p
for bubble-free solution ( m2)
- b
at bottom of electrode ( m2)
-
thickness of Nernst bubble layer (m)
- 0
ath=0 (m)
- 0,i0 ati
-
voidage
- x,0
atx andh=0
- 0,0
voidage at the leading edge of electrode wherex=0 andh=0
-
0,0 atib
-
0,0 ati=it
- ,h
voidage in bulk of solution at heighth
- ,20
voidage in bubble of solution at the leading edge of segment pair 20
- lim
maximum value of 0,0
-
overpotential (V)
- a
anodic overpotential (V)
- c
cathodic overpotential (V)
- h
hyper overpotential (V)
- h,a
anodic hyper overpotential (V)
- h,c
cathodic hyper overpotential (V)
-
fraction of electrode surface area covered by of bubbles
- a
for anode
- c
for cathode
-
resistivity of solution ( m)
- p
resistivity of bubble-free solution ( m) 相似文献
The cyclin-dependent kinase inhibitory protein p21(Cip1) might play multiple roles in cell-cycle regulation through interaction of its C-terminal domain with a defined set of cellular proteins such as proliferating cell nuclear antigen (PCNA), calmodulin (CaM), and the oncoprotein SET. p21(Cip1) could be described as an intrinsically unstructured protein in solution although the C-terminal domain adopts a well-defined extended conformation when bound to PCNA. However, the molecular mechanism of the interaction with CaM and the oncoprotein SET is not well understood, partly because of the lack of structural information. In this work, a peptide derived from the C-terminal domain of p21(Cip1) that covers the binding domain of the three above-mentioned proteins was used to demonstrate that the C-terminal domain of p21 recognizes multiple ligands through its ability to adopt multiple conformations. The conformation is dictated by tertiary contacts rather than by the primary sequence of the protein. Our results suggest that the C-terminal domain of p21(Cip1) adopts an extended structure when bound to PCNA and probably when bound to the oncoprotein SET, but an alpha helix when bound to CaM. 相似文献