N-GlcNAc has a plant growth promoting effect

A group from State Key Laboratory of Food Nutrition and Safety, College of Food Science and Engineering, Tianjin University of Science and Technology, Tianjin, China, etc. has demonstrated that N-GlcNAc has a plant growth promoting effect.

Chitin is the second most abundant polysaccharide in living organisms, following cellulose. Chitin and chitosan are biodegradable and nontoxic, drawing increasing attention due to their ability to improve soil and substrate quality, plant growth, and plant resilience and to contribute extensively to the development of enhanced and sustainable crop production. The addition of chitin and its derivatives can improve the fresh yield weight of many crops. However, knowledge of their specific functions in plant growth promotion, cultivation, and agro-environmental sustainability remains limited, restricting their further contribution to yield increase, the predictable activation of plant defenses, the extension of harvest storage life, and the improvement of slow release of optimized nutrients in fertilizers for agricultural products and their microbiomes.
N-Acetyl-D-glucosamine (N-GlcNAc), the most abundant carbon-nitrogen bio compound on Earth, is a derivatized glucose monomer found in polymers of chitin, chitosan, and peptidoglycan, which are major constituents of arthropod exoskeletons, filamentous fungi, and bacterial cell walls.

Using Tomato as a model plant, a hypothesis that N-GlcNAc promotes plant growth was examined. As expected, N-GlcNAc-treated plants produced greater plant height, greater whole fresh weight, and greater stem weight in natural soil. The increase in plant height of N-GlcNAc-exposed plants was 1.29-fold comparing with the control. The whole fresh weight of N-GlcNAc-exposed plants was 1.33-fold that of plants comparing with the control.

The rhizosphere soil samples exposed to N-GlcNAc contained 142 unique OTUs that contained relatively abundant Proteobacteria, Actinobacteria, and Planctomycetes. The relative abundance of Proteobacteria and Actinobacteria in the rhizosphere soil samples of N-GlcNAc-exposed plants was increased by 3.89% and 45.82% comparing with the control, respectively.

Interestingly, auxin indole-3-acetic acid (IAA) produced by B. cereus increased with N-GlcNAc treatment and reached 92.9 mg/L when cocultured with 60 mmol/L N-GlcNAc in LB medium. This ability of N-GlcNAc to activate IAA production was dependent on supplying the exogenous substrate tryptophan to the strains of P. mirabilis and P. putida. The addition of tryptophan also promoted the accumulation of IAA in strains of B. cereus and S. thermocarboxydus.

Thus, this study provides a new direction for understanding and utilizing the benefits and stability of PGPRs in the field and reveals a key microbial signaling molecule, N-GlcNAc, which shapes the microbial community structure and induces changes in metabolism of the rhizosphere microbiome, thereby simultaneously enhancing plant growth.

Trichoderma wheat seed dressing reduces Fusarium in the rhizosphere microbiome

A group from School of Bioengineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan, China, etc. has reported about effects of inoculation of Trichoderma atroviride HB20111 onto wheat rhizosphere microbiome.

Fusarium crown rot and wheat sharp eyespot are major soil-borne diseases of wheat.
Biological agents Streptomyces, Bacillus subtilis, Pseudomonas, Actinomyces, Trichoderma, etc. can reduce the colonization of pathogenic fungi, produce antibiotics and organic compounds in the soil, and promote plant growth. Seed dressing is a cost-effective method that has the potential for large-scale application in the prevention and control of crop diseases. As a biocontrol agent, Trichoderma seed dressing has been increasingly used to control plant fungal diseases. Common pathogens controlled by Trichoderma include Bipolaris sorokiniana, F. pseudograminearum, F. oxysporum, R. solani, R. cerealis and many other plant pathogens.

The copy number measured by qPCR of total fungi in T. atroviride HB20111 treatment was lower 47.2% than that of the control. Ascomycota and Olpidiomycota were changed significantly in the rhizosphere fungal community following Trichoderma seed dressing, compared with the control, among which, the content of Ascomycetes decreased by 54.2%, and the Olpidiomycota increased by 54.8%. Trichoderma treatment reduced the relative abundance of Fusarium spp. The relative abundance of Alternaria spp. in the Trichoderma treatment decreased by 3.26% compared with the control. These decreases were accompanied by notable increases in the relative abundance of Olpidium and Botryotrichum in the rhizosphere soil.

As a result of the Trichoderma treatment, for Fusarium crown rot, Trichoderma treatment reduced the disease index by 64.3%, and the yield of wheat treated with Tricoderma seed dressing increased by 7.7% compared with the control.

Diagnosis of hepatocellular carcinoma (HCC) using AFP-L3 as the marker: Using 3 kinds of probes made by molecular imprinting of the marker

A group from State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, China has reported diagnosis of hepatocellular carcinoma (HCC) using AFP-L3 as the marker and using new probes made by molecular imprinting of the marker.

A new strategy called triple MIP-based PISA (triMIP-PISA) was developed for precise disease diagnosis by detecting changes of glycosylation of glycoprotein disease biomarkers. This method benefits greatly from the excellent protein-recognizing properties of MIPs that approach those of monoclonal antibodies, as well as the excellent monosaccharide-recognizing properties of MIPs, outperforming lectins.

This strategy utilized triple recognition of the glycoprotein biomarker by three different types of Molecular Imprinted Polymers(MIPs) integrated with plasmonic detection.
An N-terminal epitope-imprinted substrate was used to specifically extract the target glycoprotein from clinical samples, then the captured target molecules were labelled with C-terminal epitope-imprinted nanotags encapsulated with Raman reporter 1, while the fucosylated glycans of the glycoprotein were labelled with fucose (Fuc)-imprinted nanotags encapsulated with Raman reporter 2, which has characteristic Raman peaks distinct from those of reporter 1. Sandwich-like immunocomplexes formed on the substrate were subject to plasmonic detection.

In this report, this method was applied to HCC diagnosis using AFP-L3 as the marker. Raman signal generated by reporter 1-containing nanotags reports the total AFP level, while that by the reporter 2-containing nanotags reports the level of fucosylated glycans of AFP (also referred to as L3). Thus, the relative expression level of fucosylated glycoforms over the total level of AFP in human serum (AFP-L3/AFP) can function as a reliable and specific indicator for HCC patients. The Kd value of the AFP N-terminal epitope imprinted substrate could reach 10−9 M level, which is much smaller than that of LCA lectin.

Serum O-glycosylated hepatitis B surface antigen (HBsAg) level could be used to evaluate serum HBV virion levels

A group from Department of Gastroenterology and Hepatology, Juntendo University Shizuoka Hospital, 1129 Nagaoka, Izunokuni-shi, Shizuoka, 410-2295, Japan, etc. has reported that the serum O-glycosylated hepatitis B surface antigen (HBsAg) level can be used to evaluate serum HBV virion levels through conventional immunoassay and may be a novel potential biomarker of viral kinetics, especially in patients receiving NA therapy.

Currently, oral administration of nucleos(t)ide analogs (NAs) is the most popular treatment strategy for patients with CHB because of the excellent virologic efficacy and safety profile of NAs. Long-term administration of NAs suppresses HBV replication in most patients, resulting in biochemical remission and histological improvement, including the regression of fibrosis and cirrhosis. However, HBV infection cannot be completely eliminated because of the persistence of intrahepatic covalently closed circular DNA (cccDNA). Measuring the intrahepatic cccDNA concentration would be the most direct way to assess the replication-competent viral reservoir. However, there are limitations, including the need for liver biopsy and the lack of a standardized method to quantify cccDNA.

HBsAg has long served as a qualitative serological marker for the diagnosis of HBV infection. Quantitative HBsAg assay has demonstrated that serum HBsAg levels are correlated with serum HBV DNA levels and intrahepatic cccDNA levels, and show prognostic significance. However, currently available HBsAg assays cannot distinguish between HBV virions and non-infectious subviral particles (SVPs). Recently, O-glycosylation of the PreS2 domain of M-HBsAg was identified as a distinct characteristic of genotype C HBV virions via a glycan-based immunoassay, and a recombinant antibody that specifically recognizes O-glycosylated M-HBsAg (anti-Glyco-PreS2 antibody) was developed.

Authors have found that the serum O-glycosylated HBsAg level can be used to evaluate serum HBV virion levels through conventional immunoassay and may be a novel potential biomarker of viral kinetics, especially in patients receiving NA therapy.

Palmitoylethanolamide (PEA) would be a promising adjuvant in the therapy of COVID-19

A group from Retrovirus Center, Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, 56100 Pisa, Italy, etc. has reported that palmitoylethanolamide (PEA) would be a promising adjuvant in the current therapy of COVID-19 or against emerging RNA viruses that share the same route of replication as coronaviruses.

One of the candidate inhibiting molecules against SARS-CoV-2 was PEA, one of the members of the N-acyl-ethanolamine family. PEA has been shown to inhibit peripheral inflammation and mast cell degranulation as well as to exert neuroprotective and antinociceptive effects in rats and mice. Recently, it was discovered that the anti-inflammatory activity of PEA does not follow the same route as anandamide. PEA-induced analgesic and anti-inflammatory activities are mediated by the activation of peroxisome proliferator receptor alpha (PPAR-α). PPAR-α generates a signaling cascade that leads to the disruption of lipid droplets by the activation of β-oxidation within mitochondria and peroxisomes, and the concomitant stimulation of omega-oxidation in microsomes. The efficacy of PEA in the prevention or treatment of bacterial and viral infections has also been reported. This encouraging evidence in the literature has stimulated research as to whether PEA can be used to inhibit the pathogenesis of SARS-CoV-2.

No PEA toxicity was detected, even when PEA was present as high as 100 μM in Huh-7 and 293T cells. When Huh7 cells were infected with SARS-CoV-2 virions incubated or not with PEA at 1 μM, the amount of SARS-CoV-2 genomes were reduced by ~64%, as detected by qRT-PCR 72 h after infection.

The effect of PEA was evaluated against SARS-CoV-2 two variants (Delta and Omicron). It was shown that PEA-pretreated Huh-7 cells at 10 and 1 μM reduced the numbers of viral genomes by 62.4% and 51.2% for SARS-CoV-2 Delta and by 43.4% and 77.3% for the Omicron variant, respectively. Interestingly, it was found that SARS-CoV-2 Delta and Omicron virions exposed to PEA showed a reduction in viral genomes/cell up to nearly 65% for both variants with 10 μM PEA. Also, when PEA was applied to both cells and virions simultaneously. PEA administered at 1 μM led to significant reductions in the number of viral genomes in cell lysate that were quantified as 75.3% and 72.5% for the Delta and Omicron VOCs, respectively.

A novel method to detect O-GlcNAcylated proteins with a disaccharide-tag and WJA lectin

A group from Faculty of Integrated Biosciences, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Chiba, Japan, etc. has reported a novel method to detect O-GlcNAcylated proteins specifically and with high sensitivity.

O-GlcNAc modification of serine or threonine occurs only on nuclear or cytoplasmic proteins. This modification is significantly different from N-glycosylation or O-glycosylation from several perspectives.
(1) O-GlcNAcylation occurs in the nucleus or cytoplasm of the cell, whereas general glycosylation occurs in the luminal regions of the endoplasmic reticulum and Golgi apparatus.
(2) O-GlcNAcylation is a reversible reaction via the actions of O-GlcNAc transferase (OGT) and O-GlcNAcase (OGA), although N- and O-glycosylation are irreversible.
(3) general N- and O-glycans on proteins are sequentially processed and elongated with many types of glycosyltransferases. However, O-GlcNAc residues cannot be modified by other monosaccharides.

In this study, to detect O-GlcNAc modification of proteins, especially in the nucleus of the cell, expression vectors encoding soluble β4GalNAc-TA were constructed with a nuclear localization signal (NLS) from the SV40 large T antigen at the N- or C-terminus, respectively, and let β4GalNAc transferase transfer GalNAc to the GlcNAc residue of the O-GlcNAcylated proteins forming GalNAcβ1-4GlcNAc disaccharide. Then, Wisteria japonica agglutinin (WJA) was used as a probe to detect GalNAcβ1-4GlcNAc disaccharide, because WJA is highly specific for GalNAcβ1-4GlcNAc.
This method was named as disaccharide-tag method.

The binding between GalNAc-GlcNAc used in this method and WJA lectin has a stronger Ka of 1.4 x 105 M-1 which enables higher sensitivity than any other methods. In addition, it should be emphasized that sugar chains with the GalNAc-GlcNAc sequence were hardly expressed in animal cells. The GalNAc-GlcNAc structure is found at the non-reducing end of the N-type sugar chain of pituitary glycoprotein hormones (leutropin, thyrotropin, follitropin), which serves as a clearance signal from the blood stream. These glycoprotein hormones are present only in the pituitary gland and are not expressed in other tissues and cells.

Burkholderia vietnamiensis B418 could be an effective biological nematicide for nematode management

A group from School of Bioengineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan, 250353, China, etc. has reported that Burkholderia vietnamiensis B418 is an effective biological nematicide for nematode management.

Root-knot nematodes (RKN), Meloidogyne spp., are highly polyphagous sedentary parasites capable of infesting a wide range of crops especially in greenhouse vegetable cultivation. During infestation, RKN can incite obvious knots or galls on plant roots, destroy the normal structure of the roots, compete with the host for water and nutrition, and make the host susceptible to secondary pathogens. Globally RKN damage is estimated to cause an annual economic loss of over $100 billion, accounting for about 12.6% of total crop losses.

The effects of different treatments on the reduction rate of nematode density and control efficacy against RKN are as follows.
All treatments (Burkholderia vietnamiensis B418 inoculation, fosthiszate, and avermectin) reduced nematode density to some extent compared with the negative control.
The highest reduction rate and control efficacy was observed with B. vietnamiensis B418 inoculation alone by 74.84% and 71.15%, respectively.
The introduction of B418 enhanced the inhibitory effects of chemical nematicide fosthiazate (from 38.92% to 62.71%) and biological nematicide avermectin (from 59.24% to 67.87%), which were still lower than that of B418 inoculated alone, indicating there was slight incompatibility within the combinations of B418 with fosthiazate and avermectin.

The application of B418 increased bacterial 16S rRNA sequences from 9.1% to 34.6%, and fungal ITS-2 rRNA sequences from 7.1% to 30.3%, which both exhibited more variation than the disease control treatments (9.1%).

The beneficial effects of PGPR on plant growth involve either direct mechanism such as biofertilization (facilitation of nutrient uptake including nitrogen and phosphorus primarily) and phytostimulation (production of plant growth promoting hormones), or indirect mechanism as biocontrol agents that antagonize the deleterious effects of phytopathogens by producing inhibitory substances or by inducing plant systemic resistance. The reason why inoculation of B. vietnamiensis B418 was effective in inhibiting RKN. However, it was found that the increment of Mortierella with B418 application was in accordance with the control effect against RKN. These variations in fungal community indicated that B418 inoculation resulted in the inhibition of pathogen-related species and the enhancement of plant-beneficial ones.

CK: control; FOST: fosthiazate; AVM: avermectin. (+ /−) stands for with and without B418 inoculation.

Novel serum glycan monosaccharide composite-based biomarkers for colorectal cancer (CRC) and colorectal adenoma (CRA)

A group from Department of Hepatobiliary and Pancreatic Surgery, The Affiliated Hospital of Qingdao University, Qingdao, China, etc. has developed novel serum glycan monosaccharide composite-based biomarkers for colorectal cancer (CRC) and colorectal adenoma (CRA).

HPAEC-PAD method was used to quantify the concentrations of two free monosaccharides (Glc-F and Man-F) and the six hydrolyzed monosaccharides (Fuc-H, GalN-H, GlcN-H, Gal-H, Glc-H, and Man-H) in the sera of healthy individuals, CRA, and CRC patients.
The concentrations of monosaccharides in serum were significantly higher in CRA and CRC patients than in healthy individuals. In concreat, concentrations of Fuc-H, GalN-H, GlcN-H, Gal-H, Glc-H, and Man-H in serum were significantly higher in CRC patients compared with healthy individuals. In addition, concentrations of Fuc-H, Gal-H, Glc-H, and Man-H in serum were significantly higher in CRA patients than healthy individuals

The logistic regression analysis was used to develop diagnostic models based on the above results. Tow types of the models were developed, one is MC1 and the other is MC2.
The logistic regression equation for MC1 was as follows: MC1 = -8.18 – 0.021 Fuc-H – 0.004 GlcN-H + 0.011 Man-H, where the Fuc-H, GlcN-H and Man-H were in μmol/L, and
the logistic regression equation for MC2 was as follows: MC2= -6.639 – 0.022 Fuc-H + 0.003 Gal-H + 0.003 Man-H, where the Fuc-H, Gal-H and Man-H were in μmol/L

MC1 was used to distinguish between healthy individuals and CRC, and MC2 was used to distinguish between healthy individuals and CRA. Area under receptor operating characteristic curve (AUC) of MC2 and MC1 was 0.8025 and 0.9403 respectively.
As a reference, the AUC of the existence marker CEA between healthy individuals and CRC was 0.7384.

Diagnosis of IgA nephropathy (IgAN): A sandwich assay focusing on aberrant glycosylation of serum IgA1 with WFA lectin

A group from Reagent Engineering, Protein Technology Group, Sysmex Corporation, Kobe 651-2271, Hyogo, Japan, etc. has reported about evaluation of serum WFA+-IgA1 as IgA nephropathy (IgAN) diagnostic marker.

Authors have reported results of an automated sandwich immunoassay system for diagnosing IgA nephropathy (IgAN), using Wisteria floribunda agglutinin (WFA) lectin and anti-IgA1 monoclonal antibody focusing on aberrant glycosylation of IgA1.

The usefulness of WFA for the immunoassays was investigated by lectin microarray. A figure below shows the typical images of microarray results in HC and IgAN patients, and it was confirmed that the WFA signal increased significantly in IgA1 derived from IgAN patients compared with that in HCs.

Unfortunately, the results seemed to be disappointing from a view point of diagnostic assay, i.e., Sensitivity = 66% and Specificity = 62%.

The importance of booster vaccine doses for protection against all Omicron variants

A group from Center for Retrovirus Research, The Ohio State University, Columbus, OH 43210, USA, etc. has reported about the importance of booster vaccine doses for protection against all Omicron variants.

There are several Omicron sub-lineages with significant variations in their S proteins, including BA.1, BA.1.1, and BA.2. While the constellation of mutations varies between isolates, the BA.1.1 lineage is defined by the presence of a single R346K mutation that is absent from the BA.1 lineage, whereas the BA.2 lineage is defined by key S mutations T19I, L24S, Δ25/27, V213G, T376A, and R408S. Although BA.1 was the major variant during the Omicron wave of the pandemic, the BA.2 variant, and to a lesser extent BA.1.1, has begun to account for an increasing proportion of cases. In particular, the BA.2 variant exhibits enhanced transmissibility relative to BA.1 and can reinfect previously BA.1-infected individuals.

In this study, authors have demonstrated the followings:
Omicron BA.1.1 is effectively neutralized by Omicron patient sera, and Omicron sub-lineages are comparably neutralized by Omicron patient sera.
Omicron BA.1 and BA.2 are resistant to neutralization by two-dose mRNA vaccination but sensitive to neutralization after a booster dose.

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