scholarly journals Genetic and Phenotypic Characterization of GII-4 Noroviruses That Circulated during 1987 to 2008

2010 ◽  
Vol 84 (18) ◽  
pp. 9595-9607 ◽  
Author(s):  
Yang Yang ◽  
Ming Xia ◽  
Ming Tan ◽  
Pengwei Huang ◽  
Weiming Zhong ◽  
...  
Keyword(s):  
Host Immunity ◽  
Phenotypic Characterization ◽  
Blood Group Antigens ◽  
Binding Assays ◽  
The Past ◽  
Antigenic Properties ◽  
Two Factors ◽  
Genetic Clusters ◽  
High Conservation

ABSTRACT The predominance and continual emergence of new variants in GII-4 noroviruses (NVs) in recent years have raised questions about the role of host immunity and histo-blood group antigens (HBGAs) in NV evolution. To address these questions, we performed a genetic and phenotypic characterization of GII-4 variants circulating in the past decade (1998 to 2008). Ninety-three GII-4 sequences were analyzed, and of them, 16 strains representing 6 genetic clusters were selected for further characterization. The HBGA binding properties were determined by both saliva- and oligosaccharide-binding assays using P particles as a model of NV capsid. The antigenic properties were also examined by enzyme immunoassay (EIA), Western blot analysis, and receptor blocking assay, using P-particle-specific antibodies from immunized mice and GII-4 virus-infected patients. Our results showed that 15 of the 16 GII-4 viruses bound to saliva of all A, B, and O secretors. Oligosaccharide binding assays yielded largely consistent results, although the binding affinities to some oligosaccharides varied among some strains. The only nonbinder had a mutation in the binding site. While antigenic variations were detected among the 16 strains, significant cross-blocking on the HBGA binding was also noted. Sequence alignment revealed high conservation of HBGA binding interfaces with some variations in adjacent regions. Taken together, our data suggested that the ability of GII-4 to recognize different secretor HBGAs persisted over the past decade, which may explain the predominance of GII-4 over other genotypes. Our data also indicated that both the host immunity and HBGAs play a role in NV evolution. While host immunity may continue driving NV for antigenic change, the functional selection by the HBGAs tends to lock the architecture of the capsid/HBGA interfaces and allows only limited variations outside the HBGA binding sites. A potential outcome of such counterselection between theses two factors in NV evolution is discussed.

scholarly journals Evolution of the interactions between GII.4 noroviruses and histo-blood group antigens: Insights from experimental and computational studies

2021 ◽  
Vol 17 (7) ◽  
pp. e1009745
Author(s):  
Yu Liang ◽  
Wei Bu Wang ◽  
Jing Zhang ◽  
Jun Wei Hou ◽  
Fang Tang ◽  
...  
Keyword(s):  
Binding Affinity ◽  
Blood Group ◽  
Hansenula Polymorpha ◽  
Binding Pocket ◽  
Enzyme Linked Immunosorbent Assay ◽  
Viral Gastroenteritis ◽  
Blood Group Antigens ◽  
Computational Studies ◽  
Binding Assays ◽  
The Past

Norovirus (NoV) is the major pathogen causing the outbreaks of the viral gastroenteritis across the world. Among the various genotypes of NoV, GII.4 is the most predominant over the past decades. GII.4 NoVs interact with the histo-blood group antigens (HBGAs) to invade the host cell, and it is believed that the receptor HBGAs may play important roles in selecting the predominate variants by the nature during the evolution of GII.4 NoVs. However, the evolution-induced changes in the HBGA-binding affinity for the GII.4 NoV variants and the mechanism behind the evolution of the NoV-HBGA interactions remain elusive. In the present work, the virus-like particles (VLPs) of the representative GII.4 NoV stains epidemic in the past decades were expressed by using the Hansenula polymorpha yeast expression platform constructed by our laboratory, and then the enzyme linked immunosorbent assay (ELISA)-based HBGA-binding assays as well as the molecular dynamics (MD) simulations combined with the molecular mechanics/generalized born surface area (MMGBSA) calculations were performed to investigate the interactions between various GII.4 strains and different types of HBGAs. The HBGA-binding assays show that for all the studied types of HBGAs, the evolution of GII.4 NoVs results in the increased NoV-HBGA binding affinities, where the early epidemic strains have the lower binding activity and the newly epidemic strains exhibit relative stronger binding intensity. Based on the MD simulation and MMGBSA calculation results, a physical mechanism that accounts for the increased HBGA-binding affinity was proposed. The evolution-involved residue mutations cause the conformational rearrangements of loop-2 (residues 390–396), which result in the narrowing of the receptor-binding pocket and thus tighten the binding of the receptor HBGAs. Our experimental and computational studies are helpful for better understanding the mechanism behind the evolution-induced increasing of HBGA-binding affinity, which may provide useful information for the drug and vaccine designs against GII.4 NoVs.

scholarly journals The Physcomitrium (Physcomitrella) patens PpKAI2L receptors for strigolactones and related compounds function via MAX2-dependent and independent pathways

2021 ◽  
Author(s):  
Mauricio Lopez-Obando ◽  
Ambre Guillory ◽  
François-Didier Boyer ◽  
David Cornu ◽  
Beate Hoffmann ◽  
...  
Keyword(s):  
Physcomitrella Patens ◽  
Phenotypic Characterization ◽  
Binding Assays ◽  
Single Clade ◽  
J Proteins ◽  
F Box Protein ◽  
Related Compounds ◽  
Peculiar Behavior ◽  
Dependent Pathway

Abstract In angiosperms, the α/β hydrolase DWARF14 (D14), along with the F-box protein MORE AXILLARY GROWTH2 (MAX2), perceives strigolactones (SL) to regulate developmental processes. The key SL biosynthetic enzyme CAROTENOID CLEAVAGE DIOXYGENASE8 (CCD8) is present in the moss Physcomitrium patens, and PpCCD8-derived compounds regulate moss extension. The PpMAX2 homolog is not involved in the SL response, but 13 PpKAI2LIKE (PpKAI2L) genes homologous to the D14 ancestral paralog KARRIKIN INSENSITIVE2 (KAI2) encode candidate SL receptors. In Arabidopsis thaliana, AtKAI2 perceives karrikins and the elusive endogenous KAI2-Ligand (KL). Here, germination assays of the parasitic plant Phelipanche ramosa suggested that PpCCD8-derived compounds are likely non-canonical SLs. (+)-GR24 SL analog is a good mimic for PpCCD8-derived compounds in P. patens, while the effects of its enantiomer (−)-GR24, a KL mimic in angiosperms, are minimal. Interaction and binding assays of seven PpKAI2L proteins pointed to the stereoselectivity towards (−)-GR24 for a single clade of PpKAI2L (eu-KAI2). Enzyme assays highlighted the peculiar behavior of PpKAI2L-H. Phenotypic characterization of Ppkai2l mutants showed that eu-KAI2 genes are not involved in the perception of PpCCD8-derived compounds but act in a PpMAX2-dependent pathway. By contrast, mutations in PpKAI2L-G, and -J genes abolished the response to the (+)-GR24 enantiomer, suggesting that PpKAI2L-G, and -J proteins are receptors for moss SLs.

BIOLOGICAL AND IMMUNOLOGICAL CHARACTERIZATION OF ANTIGONADOTROPHIC PROFILES

1969 ◽  
Vol 62 (1_Suppl) ◽  
pp. S31-S53 ◽  
Author(s):  
C. Robyn
Keyword(s):  
Biological Activities ◽  
Follicle Stimulating Hormone ◽  
Human Chorionic Gonadotrophin ◽  
The Past ◽  
Antigenic Properties ◽  
Biological Specificity ◽  
Human Menopausal Gonadotrophin ◽  
Quantitative Basis ◽  
Complex Relationships

ABSTRACT During the past few years a series of papers (Robyn et al. 1968; Robyn & Diczfalusy 1968a,b,c; Robyn et al. 1969; Petrusz et al. (1970) were published from this laboratory on the problems of statistically valid bioassays of gonadotrophin neutralizing potencies of antisera. These bioassays were based on the principle of »simple additivity« (or rather, subtractivity) of Hormone (H) and Antiserum (AS). Experiments conducted at several levels of neutralization of H by AS, ranging from 20 to 90 %, supported the validity of the principle of »simple additivity«. The human chorionic gonadotrophin (HCG), the luteinizing hormone (LH) and the follicle stimulating hormone (FSH) neutralizing potencies of rabbit anti-HCG sera, anti-human hypophysial gonadotrophin (anti-HHG) sera and anti-human menopausal gonadotrophin (anti-HMG) sera were estimated comparatively. The establishment of such antigonadotrophic profiles of antisera has several advantages. It makes it possible to improve the biological specificity of antisera by absorption procedures carried out on a strictly quantitative basis by selecting an appropriate amount of a gonadotrophin preparation with the adequate LH:FSH ratio. Also, it makes possible to improve the biological specificity of gonadotrophin preparations by absorption procedures carried out on a quantitative basis by selecting the appropriate excess of an antiserum with the adequate anti-LH:anti-FSH ratio. Finally the characterization of the antigonadotrophic profile of antisera together with that of the gonadotrophic profile of antigens provides improved tools for the study of the very complex relationships between the biological activities and the antigenic properties of gonadotrophic molecules. It is hoped, therefore, that the use of these methods will be of assistance in improving the specificity of current immunoassays for gonadotrophins.

The Use of Advanced Analytical Techniques for Characterization of the Chemical, Physical, and Crystallographic Nature of a Surface

1973 ◽  
Vol 31 ◽  
pp. 132-133 ◽  
Author(s):  
R. E. Herfert
Keyword(s):  
Surface Characterization ◽  
Analytical Techniques ◽  
X Ray Diffraction ◽  
Depth Of Penetration ◽  
X Ray ◽  
The Past ◽  
Transmission Electron ◽  
Scanning Electron

Studies of the nature of a surface, either metallic or nonmetallic, in the past, have been limited to the instrumentation available for these measurements. In the past, optical microscopy, replica transmission electron microscopy, electron or X-ray diffraction and optical or X-ray spectroscopy have provided the means of surface characterization. Actually, some of these techniques are not purely surface; the depth of penetration may be a few thousands of an inch. Within the last five years, instrumentation has been made available which now makes it practical for use to study the outer few 100A of layers and characterize it completely from a chemical, physical, and crystallographic standpoint. The scanning electron microscope (SEM) provides a means of viewing the surface of a material in situ to magnifications as high as 250,000X.

Comprehensive phenotypic characterization of ABCB4 deficient mice reveals systemic effects of spontaneous biliary fibrosis

2009 ◽  
Vol 47 (01) ◽  
Author(s):  
K Hochrath ◽  
S Hillebrandt ◽  
F Lammert ◽  
B Rathkolb ◽  
H Fuchs ◽  
...  
Keyword(s):  
Phenotypic Characterization ◽  
Systemic Effects ◽  
Deficient Mice

Studies on the Characterization of Factor VIII and a Co-factor VIII

1974 ◽  
Vol 31 (02) ◽  
pp. 328-338
Author(s):  
M. M. P Paulssen ◽  
H. L. M. A Vandenbussche-Scheffers ◽  
P. B Spaan ◽  
T de Jong ◽  
M. C Planje
Keyword(s):  
Molecular Weight ◽  
Factor Viii ◽  
The Body ◽  
Haemophilia A ◽  
Von Willebrand's Disease ◽  
Von Willebrand’S Disease ◽  
Polysaccharide Content ◽  
Plasma Factor ◽  
Two Factors

SummaryFactor VIII occurs in the body in two different forms. In lymph factor VIII is bound to chylomicra. In plasma, factor VIII is bound to a protein.After delipidation of chylomicra we obtained a glycoprotein with a high polysaccharide content and a molecular weight of approx. 160,000.In plasma, factor VIII is attached to a protein which is present in normal concentrations in plasma of patients with haemophilia A and in serum (co-factor VIII).This factor is deficient in both the plasma and the serum of patients with von Willebrand’s disease.The binding between factor VIII and co-factor VIII is reversible.Some properties of these two factors are described.

Sign in / Sign up

Export Citation Format

Share Document