Year: 2021

A group from Molecular and Cellular Modeling Group, Heidelberg Institute for Theoretical Studies (HITS), 69118 Heidelberg, Germany, etc. has reported about three roles of heparin in inhibiting SARS-CoV-2 infection with using molecular dynamics simulations.
https://pubmed.ncbi.nlm.nih.gov/34929169/

Heparin can inhibit SARS-CoV-2 infection by three mechanisms:

(1) Heparin binds the S1/S2-heparin binding domain (HBD) of spike in both the conformations, preventing furin cleavage,
(2) hinders the opening/activation of the closed spike, and
(3) acts allosterically on the hinge region associated with the movement of the RBD, while directly masking the RBD-HBD.

A group from Department of Plant Pathology, Washington State University, Pullman, WA, USA, etc. has reported that wheat genotype and physiological stage shaped the microbiome, which was able to significantly alter soil suppression of pathogen R. solani AG-8.
https://pubmed.ncbi.nlm.nih.gov/34925393/

Microbiomes have drawn a great deal of attention and studies have begun focusing on manipulating these microbiomes in order to strengthen sustainable agricultural systems. In this context, genotype-specific recruitment of the microbiome is also gaining interest with the idea that host genotypes will attract bacteria with specific outcomes in different agroecosystems.

In this study, rhizosphere microbiome recruitment of six winter wheat genotypes (Eltan, Madsen, Hill81, Lewjain, PI561725 and PI561727) under growth chamber conditions were evaluated and have been found to be genotype-specific with increasing growth chamber daycicles. At 160-daycyles, microbiomes of PI561725 and PI561727 were clearly differentiated from others as shown below.

As aresult, differential abundance of Burkholderiales OTUs, specifically the genus Janthinobacterium in PI561727 and PI561725 cultivated soils, was associated with reduced root disease and better wheat growth. It is known that Burkholderiales OTUs could be a putative biological control agent against pathogen R. solani AG-8. Thus, using an appropriate wheat genotype to manipulate the rhizosphere microbiome could provide a sustainable approach to manage soil-borne disease.

A group from Division of HIV/AIDS and Sex-transmitted Virus Vaccines, Institute for Biological Product Control, National Institutes for Food and Drug Control, Beijing, China. has reported on degradation of neutralization of convalescent sera against SARS-CoV-2 Omicron variant.
https://www.tandfonline.com/doi/full/10.1080/22221751.2021.2017757

A novel pseudotyped virus expressing SARS-CoV-2 Spike of Omicron (PV-Omicron) containing all of 32 mutations was constructed. The neutralization analysis of convalescent sera (28 convalescent sera from COVID-19 patients) against the PV-omicron was performed. The neutralization ED₅₀ and ratio compared to the reference strain D614G was also displayed as shown below. Th neutralization against omicron was about 5.4 times lower than that against delta variant.

A group from National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA, etc. has reported on effects of SARS-CoV-2 Omicron variant onto existing SARS-CoV-2 CD8⁺ T-cell recognition.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8669839/

This study examined if the previously identified SARS-CoV-2 viral epitopes targeted by CD8⁺ T-cells in 52 individuals are mutated in the newly described Omicron VOC (n=50 mutations), because it is critical to determine the extent that Omicron may or may not be susceptible to existing humoral responses.
T-cell associated immunity is in general significantly more difficult for viruses to overcome due to the broad and adaptable response generated in a given individual, as well as the variety of HLA haplotypes between individuals.

It was found that of the mutations associated with the Omicron variant (n=50), only one in the Spike protein (T95I) overlapped with a CD8⁺ T-cell epitope (GVYFASTEK) identified in this subject population.
Despite the substantial number of mutations in the Omicron, in this population only one low-prevalence CD8⁺ T-cell epitope from the Spike protein contained a single amino acid change. No other mutations were associated with our previously identified SARS-CoV-2 T-cell epitopes. These data suggest that virtually all individuals with existing anti-SARS-CoV-2 CD8⁺ T-cell responses should recognize the Omicron variant, and that SARS-CoV-2 has not evolved extensive T-cell escape mutations at this point.

A group from School of Life Sciences, Faculty of Medicine and Health Sciences, University of Nottingham, Nottingham, UK, etc. has reported about ええ.
https://www.nature.com/articles/s41522-021-00257-w

Pseudomonas aeruginosa is a versatile opportunistic pathogen that causes acute infection after invasive procedures and burns, and chronic infections in patients with persistent lung disease and compromised immunity1. P. aeruginosa infection is especially troublesome in people with cystic fibrosis where it is a major determinant of irreversible loss of lung function and mortality.

Several new findings have emerged from this study.
(i) demonstrated robust recognition of P. aeruginosa biofilms and planktonic cells by DC-SIGN (CD209), and weak recognition of biofilms by MR (CD206) and Dectin-2;
(ii) showed binding of DC-SIGN, MR and Dectin-2 to purified biofilm carbohydrates, particularly to the high molecular weight fractions;
(iii) provided evidence for biofilm carbohydrates affecting DC-SIGN, MR and Dectin-2 function and
(iv) established the ability of biofilm carbohydrates to modulate dendric cells phenotype.
The key message of these studies is that P. aeruginosa produces carbohydrates that have the potential to influence immunity through the engagement of C-type lectins.

Carbohydrates from biofilms were purifies and analyzed by gel filtration chromatography. The biofilm carbohydrates were divided into high (>45 kDa, HMW) and low molecular weight (<45 kDa, LMW) fractions. Further, the differences in molecular weight between the HMW and LMW preparations were analyzed in detail, and the HMW fraction was divided into two fractions as follows, 15,370 Da for LMW, and 182,300 Da and 132,670 Da, for HMW-1 and HMW-2, respectively. The hydrolysed carbohydrate monomer compositions in weight % for HMW-1 is 74.9% mannose, 14.7% glucose, 7.4% galactose, and 3.0% rhamnose, and for HMW-2 80.9% mannose, 11.0% glucose, 2.3% galactose, and 5.7% rhamnose.

A group from Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention (CDC), Atlanta, GA USA etc. has reported on changes in N-glycan profiles between the wild type (S-614D) and the variant (S-614G) SARS-CoV-2.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8651636/

The site-specific distribution and abundance of heterogeneous N-linked glycans on 21 of 22 potential sequons were characterized by mass spectrometry analysis of the glycopeptides cleaved by the a-lytic protease or the combination of trypsin and chymotrypsin.

Analysis of the S-614G variant revealed differences in the N-glycan on some glycosylation sites from those seen in S-614D. Among 21 detected and quantified sequons, 9 of these sequons including N17, N61, N74, N331, N343, N657, N1074, N1158, and N1173 had little to no significant variations in the distribution of both individual glycans and glycan types between S-614D and S-614G protein expressions while alterations were observed on 11 of sequons that include N122, N165, N234, N282, N603, N616, N709, N717, N801, N1098, and N1134.

The relative abundances of the complex-type glycans were reduced by up to 45% on those sequons with altered N-glycosylation in the S-614G glycoprotein and the contents of high-mannose glycans, in contrast, were elevated by up to 33%.