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SARS-CoV-2 antiviral activities using vegetable exosomes

A group from Nebraska Center for Virology, University of Nebraska-Lincoln, NE 68583, USA has reported about a new lectin found from shiitake exosomes.
https://www.mdpi.com/1999-4915/16/10/1546

Exosomes from fifteen local common vegetables were isolated by ultracentrifugation. These exosomes were evaluated for their antiviral activities against SARS-CoV-2 infection using an in vitro pseudovirus platform.
Their cytotoxicity using the standard MTT method indicated that all fifteen samples did not show significant cytotoxicity in a concentration of 1 × 10^10/mL exosomes. The antiviral activities of shiitake exosomes exhibited the lowest EC50 value 5.2 × 10^8/mL.
From the proteomic analysis of the exosomes, it was found that a lectin (named Shictin) of shiitake exosomes Contributed to the Antiviral Activities and exhibited strong activity against the SARS-CoV-2 Omicron variant with an IC50 value of 87 nM. It was also found that shictin is a C-type lectin and binds to GlcNAc.

Lectin staining is significantly different between formalin-fixed tissue samples and frozen tissue samples

A group from Department of Gastroenterological surgery, Gifu University School of Medicine, Gifu, Japan, has reported about differences in glycocalyx morphology and composition in frozen and formalin-fixed liver tumor sections.
https://www.sciencedirect.com/science/article/pii/S0344033824005715?via%3Dihub

It was found that surprisingly, there were many differences in lectin staining findings between frozen and formali-fixed tissue preparations, suggesting that FFPE processing affects lectin receptors, rendering frozen sections more reliable for accurate lectin staining.

From the lectin staining in frozen sections, the followings were found:
Normal hepatocytes showed strongly positive staining for PNA, RCA I, SBA, UEA I, GSL I, succinylated WGA, ECL, GSL II, STL, and VVL.
In contrast, hepatocellular carcinoma samples were strongly positive for DSL and GSL II.
Normal hepatocytes were positive for multiple GalNAc-related lectins (PNA, SBA, GSL I, and VVL), but these were not detected in hepatocellular carcinoma samples.

It was also found that DBA and UEA I staining were strongly positive in liver metastases from colorectal cancer and in melanoma liver metastases, ConA, WGA, succinylated WGA, and GSL II were strongly expressed.

It is strange that Shun-ichi Amari is not included in the 2024 Nobel Prize in Physics

It is well-known that the 2024 Nobel Prize in Physics was awarded to two scientists who contributed to neural networks.
When I was working at Fujitsu, I read papers written by Prof. Shun-ichi Amari, a pioneer in neural networks, and I remembered that I was passionately discussing the possibilities of future computers with my colleagues, and I was surprised that Prof. Amari was not included as one of the recipients of the award. I felt very uncomfortable with it.
By the way, with the power of computers at that time, it was impossible to realize a neural network as software, so I and my colleagues were thinking about building it as hardware.

Prof. Amari’s pioneering researches:
1. A Theory of Adaptive Pattern Classifiers、1967
2. Characteristics of randomly connected threshold-element networks and network systems、1971
3. Learning Patterns and Pattern Sequences by Self-Organizing Nets of Threshold Elements、1972
4. Characteristics of Random Nets of Analog Neuron-Like Elements、1972

A human lectin microarray

A group from Department of Life Sciences, Imperial College London, London, United Kingdom has reported about human lectin microarray.
https://www.jbc.org/article/S0021-9258(24)02371-8/fulltext

A human lectin array containing 39 different human CRDs from 36 sugar-binding receptors representing 7 different structural groups has been developed.
The following is a list of 39 lectins clasified into 7 groups.
MBP, SP-A, SP-D, Colk1
MMR CRD4, Langerin, DC-SIGN, DC-SIGNR, Prolectin, LSECtin, Endo180 CRD2, Mincle, Dectin-2, BDCS-2, Dectin-1
ASGPR1, ASGPR2, MGL, SRCL
Galectin-1, Galectin-2, Galectin-3, Galectin-7, Galectin-4N, Galectin-4C, Galectin-8C, Galectin-9N, Galectin-9C
Siglec-1, Siglec-3, Siglec-5, Siglec-7, Soglec-9, Siglec-11
Intelectin-1, Intelectin-2
MMR-CR, Ficolin-1, Chl3-L2

A new approach which enables of accurately detecting Canser Stem Cells (CSCs)

A group from UMR INSERM 1308 CAPTuR, Faculty of Medicine, University of Limoges, Limoges, France has reported about a new approach which enables of accurately detecting Canser Stem Cells (CSCs).
https://www.nature.com/articles/s41416-024-02839-9

A combination of plant lectins (MIX: UEA-1 and GSL-I) was used as a new approach to detect CSCs from a heterogeneous non-small cell lung cancer (NSCLC) population.

It was demonstrated that the combination of those lectins recognizing glycosylated pattern exposed on CSCs were more efficient for detecting and sorting CSCs than CD133.
CD133 is know as a CSCs marker.

Galectin-8 alters non-canonical TGF-β response in CRC cells and suppresses CRC progression

A group from Genomics Research Center, Academia Sinica, Taipei, Taiwan has reported about a glycan-binding protein modulated the TGF-β-driven signaling and metastasis of colorectal cancer (CRC).
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11375092/

This study demonstrate that galectin-8 alters non-canonical TGF-β response in CRC cells and suppresses CRC progression, although Galectin-8 is not a canonical regand of TGF-β Receprtor.

In detail, in the absence of galectin-8, TGF-β binds to type II TGF-β receptor (TβRII), thereby promoting epithelial-mesenchymal transition (EMT).
In the presence of galectin-8, galectin-8 binds to TβRII through galactosylaeted-glycans, resulting in a decrease of TGF-β signaling-mediated EMT.
It was also shown that galectin-8 expression is downregulated during CRC progression.
The expression of galectin-8 is significantly lower in T4 stage than that in T1 stage.

The recognition of hypermucoviscous Klebsiella pneumoniae clinical isolates by innate lectins

Department of Biological Physical Chemistry, Instituto de Química Física Blas Cabrera, Consejo Superior de Investigaciones Científicas, Madrid, Spain has reported about the recognition of hypermucoviscous Klebsiella pneumoniae clinical isolates by innate immune lectins of the Siglec and galectin families.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11324429/

Klebsiella pneumoniae is an opportunistic bacterium that frequently colonizes the nasopharynx and gastrointestinal tract and can also cause severe infections when invading other tissues, particularly in immunocompromised individuals.
There were striking differences in the recognition of those bacteria by sialic acid-, galactose- and mannose-specific lectins as shown below.

Extracellular Polymeric Substances (EPS) produced by bacteria used in biological wastewater treatment

A group from Department of Biotechnology, Delft University of Technology, The Netherlands has reported about extracellular polymeric substances (EPS) produced by bacteria used in biological wastewater treatment.
https://pubs.acs.org/doi/epdf/10.1021/acsestwater.4c00247

Unlike DNA replication or protein translation, glycan biosynthesis is not directed by a preexisting templatemolecule. The production of glycans is decided by a few factors: the biosynthetic machinery, the available nucleotidesugars, and signals from the intracellular and extracellular environment.
Thus, the presence of glycans is dynamic and is influenced by both geneticand environmental factors. Therefore, under such conditions, it is tremendously challenging to study the glycan composition in EPS.

Typically, approaches for studying glycoproteins in environ-mental samples involve identifying individual glycan structuresand further characterizing the proteins with mass spectrometry.
On the other hands, lectin microarrays offer a high throughput examination of the glycans on the proteinsurfaces, enabling a broader screening of a possible proteinglycosylation pattern.
So, they concluded that combining both approaches can provide acomprehensive understanding of glycoproteins, bridging the gapbetween structural characterization and functional implications

Roles of Glycan and Lectin interactions in Embryo Attachment

A group from Shenzhen Key Laboratory of Metabolic Health, Center for Energy Metabolism and Reproduction, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, China has reported about roles of glycan and lectin interactions in embryo attachment.
https://www.sciencedirect.com/science/article/pii/S2090123224003060?via%3Dihub

Althopugh the interaction between trophoblastic L-selectin and endometrial sLeX has been reported as a glycosylation-dependent adhesion mechanism underlying embryo implantation, it was also found that Siglec-6 expressed in the trophectoderm of human embryos play a key role in facilitating embryo attachment via recognizing the sTn-covered receptive endometrium.

Changes in IgG glycosylation patterns for antiphospholipid syndrome (APS) patients with lectin microarray

A group from Department of Rheumatology and Clinical Immunology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China has reported about changes in IgG glycosylation patterns for antiphospholipid syndrome (APS) patients with lectin microarray.
https://onlinelibrary.wiley.com/doi/10.1111/sji.13366

It was found that IgG complexes from APS patients exhibited a significantly elevated exposure of GalNAc residues compared with healthy controls and disease controls. This suggests that elevated GalNAc on IgG plays a role in the progression of APS. However, compared with N-linked glycosylation, the effects of O-glycosylation on IgG structure and function remain to be elucidated.

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