Month: August 2022

Nature

Membrane-anchored mucins restrict infection of multiple SARS-CoV-2 variants

A group from Division of Infectious Diseases and Vaccinology, School of Public Health, University of California, Berkeley, CA, USA, etc. has reported about key antiviral pathways in SARS-CoV-2 infection.
https://www.nature.com/articles/s41588-022-01131-x

Recent loss-of-function (LOF) screens have begun defining host factor requirements for SARS-CoV-2 infection, these studies employed host gene knockout (KO) approaches either in nonepithelial cell lines or in cell lines that do not endogenously express ACE2 and TMPRSS2. Although LOF screens can be powerful for the identification of proviral genes, gain-of-function (GOF) screens can identify antiviral factors that mediate viral restriction upon upregulation. Performing screens in a bidirectional manner can therefore illuminate host pathways with bimodal roles and provide a more comprehensive view of viral dependencies and potential targets for host-directed therapeutic development.

From these screening results, it was found that G-protein-coupled receptor (GPCR) signaling, transcriptional regulation (TAF7L, FOXE1, ZNF275, TEAD3, SPDEF, JDP2), cell-cycle regulation (CCNE1) and mucin glycosylation (MUC1, MUC4, MUC13, MUC21, B3GNT8) are key antiviral pathways in SARS-CoV-2 infection.

To determine the impact of membrane-anchored mucins on infection of diverse SARS-CoV-2 clinical isolates, we infected our MUC1 and MUC4 GOF Calu-3 lines with alpha, beta, gamma, epsilon, delta, and WA/1 variants. It was found that overexpression of either MUC1 or MUC4 restricted viral replication of diverse SARS-CoV-2 variants relative to NTG controls. Next, mucin-selective protease (StcE) treatment followed by infection with these same variants rendered Calu-3 cells significantly more permissive to viral infection. These data suggest that membrane-anchored mucins restrict infection of multiple SARS-CoV-2 variants.

Nature, Technology

Plant growth promoting ability of rhizobacteria strains isolated from Polyporus umbellatus

A group from School of Pharmaceutical Sciences, Peking University, Beijing, China, etc. has reported about mycorrhizal bacteria strains isolated from Polyporus umbellatus.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9340266/

Fungal pathogens cause a range of serious plant diseases, such as Fusarium wilt, and are responsible for most of the diseases in agricultural ecosystems.
There are two main ways to deal with the effects of these diseases:
One is to develop disease-resistant plants, and
the other is to use chemical fungicide to control the spread of pathogens.
However, these two methods have the disadvantages of long cycle and drug resistance of pathogens. A practical and sustainable strategy for dealing with phytopathogenic fungal diseases is therefore the application of biological control agents (BCAs).

Several bacteria have been isolated from plants and fungi, most of which belong to the genera Bacillus and Pseudomonas, and it has been demonstrated that those genera exhibit satisfactory biological activity and marked biocontrol potential.

In this paper, 21 rhizobacteria strains were isolated from mycorrhizal samples of Polyporus umbellatus, and evaluated from viewpoints of agricultural sustainability without requiring the overuse of hazardous fungicide and plant growth promoting ability such as producing IAA, siderophore, etc. and dissolving phosphate.

Among those isolated strains, it was found that the Pseudomonas strain ZL8 shows the highest performance as plant growth-promoting bacteria (PGPB). Nineteen compounds were identified from the fermentation broth of the strain ZL8, of which 2,4-diacetylphloroglucinol (DAPG) showed a significant inhibitory effect on phytopathogenic fungi with a minimum inhibitory concentration of 3.12–25 μg/mL. The plant growth promoting ability was evaluated with using Salvia miltiorrhiza, and the effect was so significant as shown below.

where, Fo. means Fusarium oxysporum

Nature, Technology

Green tea catechin, epigallocatechin gallate (EGCG), could be a pan-coronavirus attachment inhibitor

A group from Department of Biomedical and Molecular Sciences, Queen’s University, Kingston, ON, Canada has reported that green tea catechin, epigallocatechin gallate (EGCG), could be a pan-coronavirus attachment inhibitor.
https://www.nature.com/articles/s41598-022-17088-0

Here, it was evaluated and characterized the inhibitory activity of EGCG against entry of human seasonal and highly pathogenic coronavirus (CoVs). Then, it was demonstrated that EGCG inhibits entry of a broad range of CoVs into physiologically relevant human lung epithelial cells. And, furthermore, EGCG inhibited binding of multiple human CoVs to cell surfaces, suggesting that this natural product inhibits a highly conserved step in CoV attachment, such as primary attachment to cell-surface heparan sulfate.
Focusing on SARS-CoV-2, it was shown that EGCG competitively inhibits virion attachment to heparin, a structural analog of Heparan Sulfate. These findings further support understanding of the antiviral mechanisms of EGCG against CoVs, and identify a highly conserved antiviral target for the development of improved antiviral molecules to prevent infection with diverse CoVs, including potential future emerging CoVs.

Nature

Plant growth-promoting and biocontrol bacteria in the rhizosphere of wild rice

A group from Key Laboratory of Mollisols Agroecology, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun, China, etc. has reported about plant growth-promoting and biocontrol bacteria in the rhizosphere of wild rice.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9324538/

Rice occupies an important position in the world’s food crops, and about 50% of the populations live on rice as the staple food. Wild rice is an important improved resource for cultivated rice and its unique ability to resist biotic and abiotic stress has attracted the attention of many scholars.

The results of functions of the screened strains showed that 18 strains had a good inhibitory effect on rice blast, and 33 strains had the ability to dissolve phosphorus, potassium, or fix nitrogen. Through potted experiment, the three bacterial strains, 499G2 (Peribacillus simplex), 499G3 (Bacillus velezensis), and 499G4 (Nacillus megaterium) have a positive effect on the growth of cultivated rice in addition to the resistance to rice blast.

, where CK is a control

Technology

A lectin-Fc fusion protein (i.e., lectibody) recognizing cancer specific high mannose glycans would be a useful drug in cancer therapy

A group from Department of Pharmacology and Toxicology, University of Louisville School of Medicine, KY, USA, etc. has reported that a lectin-Fc fusion protein (i.e., lectibody) recognizing cancer specific high mannose glycans would be a useful drug in cancer therapy.
https://onlinelibrary.wiley.com/doi/10.1111/pbi.13902

Avaren-Fc (AvFc) is a lectin-Fc fusion protein (i.e., lectibody) produced in Nicotiana benthamiana, which selectively recognizes cancer-associated high-mannose glycans. A glycovariant of AvFc (AvFcΔXF) was developed by eliminating plant glycans, including the coreα1,3-fucoseand β1,2-xylose residues. The successful removal of these glycans was confirmed by glycan analysis using HPLC.

This study has demonstrated that AvFcΔXF induces more a potent ADCC response in vitro and delays the growth of murine B16F10 melanoma in both a flank tumor model as well as a model of metastasisin vivo, suggesting that high mannose glycans may be a useful druggable biomarker in cancer therapy.

where, AvFcΔlec means a variant lacking sugar-binding activity

Nature, Technology

An extract from coffee leaf (Coffea Arabica) effectively inhibited SARS-CoV-2 infection

A group from Graduate Institute of Biomedical Sciences, China Medical University, Taichung, Taiwan, etc. has reported that an extract from coffee leaf (Coffea Arabica) effectively inhibited five Variants of SARS-CoV-2 (Alpha, Beta, Gamma, Delta, and Omicron strain) from entering host cells.
https://www.ijbs.com/v18p4677.htm

At 100 μg/ml, coffee leaf extract had a significant inhibitory effect on the infection of five VOC (Alpha, Beta, Gamma, Delta, and Omicron strain) pseudoviral SARS-CoV-2 as shown below.

In the coffee extract, four main compounds, including caffeine, CGA, quinic acid, and mangiferin, were identified. ACE2 TR-FRET Assay was used to evaluate inhibitory effect of Spike-ACE2 interactions. Due to the nature of the compounds, mangiferin and CGA were soluble in DMSO, and caffeine and quinic acid were soluble in water. It was demonstrated that treatment with four main compounds could inhibit the activity of Spike-ACE2.