Month: March 2023

Technology

Development of novel antibiotics from Actinomycetia isolated from the rhizosphere soil of Juniperus excelsa

A group from Department of Genetics and Biotechnology, Ivan Franko National University of Lviv, Ukraine, etc. has reported about development of novel antibiotics from Actinomycetia isolated from the rhizosphere soil of Juniperus excelsa.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10031196/

Natural products play a key role in drug discovery, especially in the treatment of infectious diseases. However, the rapid spread of bacterial infections has been observed in recent decades, mainly due to the rapid emergence and spread of multidrug-resistant pathogens. As a consequence, there is now a general consensus that the discovery of new antibiotics is needed as the best solution in the fight against antibiotic resistance among microorganisms.

In this work, the 372 actinomycete-like strains were isolated in 2008 from rhizosphere soil of J. excelsa collected from mountainous region on the Crimean Peninsula in Ukraine. First of all, those strains were screened by means of the spot inoculation method to evaluate antimicrobial activity, and the secondary metabolite extracts from selected strains were analyzed by LC–MS and dereplication analysis.

As a result, it was found that the Streptomyces sp. Je 1–651 strain exhibited strong inhibitory activity against all of the utilised microbial test cultures, except for P. aeruginosa. In the crude extracts of the Je 1–651 strain grown on DNPM medium, there were seven peaks (indicated by Red stars below) not identified in the existing database in addition to those of spiramycins and stambomycins. This may indicate the potential novelty of antibiotic compounds, and the future research is expected.

Nature

Burkholderia gladioli strain KJ-34 exhibiting broad-spectrum antifungal activity as Plant Growth Promoting Rhizobacteria

A group from Ecological Security and Protection Key Laboratory of Sichuan Province, Mianyang Normal University, Mianyang, China, etc. has reported Burkholderia gladioli strain KJ-34 exhibiting broad-spectrum antifungal activity.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10020716/

It was shown that Burkholderia gladioli strain KJ-34 is a potential biocontrol bacterium isolated from the rhizosphere soil of rice and can fight multiple fungal pathogens (i.e. Ustilaginoidea virens, Alternaria solani, Fusarium oxysporum, Phytophthora capsica, Corynespora cassiicola).

Metabolites of this strain exhibiting antifungal activity appeared to be Ac-Yvad-cho, benzoylstaurosporine, TAXOL C, morellin, jubanine B, trichostatin A, thapsigargin, kabiramide B, scopolamine, enniatin B, latrunculin A, rifaximin, rigin, and garcinone C.

We have to be careful that some Burkholderia bacteria are pathogenic. For instance, Burkholderia gladioli BSR3 infects rice, causing bacterial blight, and another rice seed−borne bacterium, B. glumae, causes rice grain rot.

Nature

Root exudate compounds induced under low P conditions can stimulate the ability of bacteria to solubilize P

A group from Department of Horticulture and Landscape Architecture, Center for Root and Rhizosphere Biology, Colorado State University, Fort Collins, CO USA, etc. has reported that root exudate compounds (galactinol, threonine, and 4-hydroxybutyric acid) induced under low P conditions can stimulate the ability of bacteria to solubilize P.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10006420/
The effect of the three root-exudate derived compounds on the enhancement of P solubilization by bacteria was assessed.

In the calcium phosphate (inorganic) media, threonine, 4-hydroxybutyric acid, galactinol, and the combination of compounds significantly increased dissolved P in the medium for Enterobacter cloacae and Pseudomonas pseudoalcaligenes. For Bacillus thuringiensis, only threonine and 4-hydroxybutyric acid increased dissolved P.

In phytin (organic phosphate) media, the effect of the compound additions on the enhancement of P solubilization was not significant for any of the bacterial strains.

Nature

Odd phenomenon that HIV infection is enhanced by interaction with an O-glycan-specific bacterial lectin

A group from Catarina Hioe, Icahn School of Medicine at Mount Sinai, New York, USA, etc. has reported that HIV infection is enhanced by interaction with an O-glycan-specific bacterial lectin.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9949255/

I was shown that the O-glycan-specific lectin SLBR-N, which is expressed on oral commensal Streptococcus gordonii strains and recognizes α2–3 sialylated O-glycans on HIV-1, was found to enhance HIV-1 infection in the context of both cell-free virus infection and a CD4-dependent cell-to-cell viral transfer assay.
Surprisingly, virus treatment with SLBR-N enhanced virus infection up to 4-fold in a dose-dependent manner, while strangely, the interaction with high-mannose N-glycan-binding bacterial lectins FimH and Msl did not affect infectivity.

This strange mechanisms by which SLBR-N and other O-glycan-binding lectins increase HIV-1 infectivity are not fully understood.


CMU06 and C.Z331M are full length infectious molecular clones oh HIV-1.

Nature, Technology

The beneficial effect of Bacillus to suppress phytopathogen is due to double-sided nature of its secondary metabolites

A group from Faculty of Science and Technology, Thammasat University, Pathumtani, Thailand, etc. has reported that the beneficial effect of Bacillus to suppress phytopathogen is due to double-sided nature of its secondary metabolites.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9986491/

It has been known that Bacillus exhibit potent antagonistic activity against phytopathogens through the secondary metabolites, i.e., lipopeptide biosurfactants such as iturin A and surfactin.

However, such antagonistic activity of Bacillus is not only due to the direct effect of biosurfactants but also due to boosting plant immunity by the biosurfactants. Salicylic acid (SA), jasmonic acid (JA), and ethylene (ET) are important hormonal signal molecules involved in biotic stress responses during plant–pathogen interactions.
In this work, it was shown that biosurfactant treatments elevated both salicylic acid and total phenolic content, with a faster rate, whereas total phenolic content in the control treatment (i.e., 0%) was only slightly increased.


efficacy of the Bacillus biosurfactant as the sole regulator at concentrations of 20%, 25%, and 30% v/v.

Nature

Changes in glycosylation of melanoma tumor cells and its impacts on functionality of dendritic cells

A group from Institute for Advanced Biosciences, Université Grenoble Alpes, Grenoble, France, etc. has reported changes in glycosylation of melanoma tumor cells and its impacts on functionality of dendritic cells.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9986448/

It was found that higher levels of GalNAc and NeuAc residues (revealed by the interaction of WFA and MAA respectively) were observed in melanoma tumor cell lines when compared to healthy melanocytes.

The global view of tumor glyco-code profiles upon separation of patients based on better or worse overall survival (median OS) or progression-free survival (median PFS) revealed a pattern of higher expression of Thomsen-Friedenreich antigen (TF-antigen), GlcNAc, Fuc and NeuAc residues (detected by ACA, WGA, RPL-αMan, UEA-I, MAA and SNA) in tumor cell lines from patients with worse clinical outcome. Strikingly, tumor cells with higher levels of f TF-antigen and GlcNAc residuesi (detected by ACA and WGA respectively) were found in patients with worse OS, whereas tumor cells with higher levels of terminal αGalNAc (seen by HPA) were found in patients with a better PFS.
It should be highlighted that higher levels of Man/Glc residues on tumor cell lines (detected by ConA) correlate with better PFS, whereas higher levels of NeuAc and Fuc residues (detected by SNA, MAA or UEA-I respectively) predict a worse clinical outcome in melanoma patients

Interestingly, there was positive correlations between levels of Man/Glc and GlcNAc residues on tumor cells and proportions of tumor-infiltrating cDC1s. Man/Glc were linked with a good clinical outcome, and GlcNAc was a candidate to boost cDC1s’ functionality. Strikingly, levels of Fuc residues on tumors negatively correlated with infiltration by T cells, and were associated with a poor outcome. In addition, levels of TF-antigen residues on tumor cells from melanoma patients negatively correlated with tumors’ infiltration by CD8+ T cells, and were linked to a shorter survival.

Nature, Technology

Cyanobacteria lectin, CV-N, binds selectively to SARS-CoV-2 spike and blocks infection by SARS-CoV-2

A group from Molecular Targets Program, Center for Cancer Research, National Cancer Institute-Frederick, NIH, Frederick, MD, USA, etc. has reported that Cyanovirin-N binds selectively to SARS-CoV-2 spike oligosaccharides outside of the receptor binding domain (RBD) and blocks infection by SARS-CoV-2.
https://www.pnas.org/doi/full/10.1073/pnas.2214561120

Cyanovirin-N, CV-N, showed inhibitory activity against all tested variants of SARS-CoV-2 (WH-1, D614G, B1.1.7 (Alpha), P.1 (Gamma), B1.351 (Beta), B.1.617.2 (Delta), and B1.1.529 (Omicron)) with EC50 values ranging from 40 nM for Omicron to 180 nM for Alpha.

CV-N bound with good affinity to Spike protein and did not bind to the RBD. In detail, CV-N could bind oligo-mannose at N61, N122, and N234 sites of the S1 domain of Spike protein. Since the glycan at position N234 played important roles in both shielding the RBD and in stabilizing the RBD in the “up” conformation, the specific binding of CV-N to the S1 domain of Spike at 234 might sterically block the RBD binding to ACE2.

Nature

Paenibacillus produces antibiotics suppressing fusarium head blight of wheat

A group from School of Food Science, Henan Institute of Science and Technology, Xinxiang, China, etc. has reported about Paenibacillus polymyxa 7F1 suppressing fusarium head blight of wheat.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9963053/

Fusarium head blight is a severe disease of wheat, corn, barley, and other grain and occurs in all regions worldwide. Several bacteria and fungi have been found to inhibit the growth of Fusarium graminearum. Among the antimicrobial agents identified, Bacillus is the most compelling antibiotic-producing strain, and it has more advantages than other biocontrol microorganisms due to its inherent endospore formation and resistance to extreme conditions.

Paenibacillus polymyxa 7F1 was isolated from the rhizosphere of a wheat field, and it was shown that Paenibacillus polymyxa 7F1 showed high antifungal activity against all fungi strains tested in this study.


Antifungal activity of Paenibacillus polymyxa 7F1 against seven pathogenic fungi. 1. Fusarium equiseti, 2. Fusarium verticillioide, 3. Fusarium semitectum, 4. Fusarium graminearum, 5. Colletotrichum gloeosporioides, 6. Fusarium proliferatum, 7. Fusarium oxysporum

The antibiotics produced by Paenibacillus polymyxa 7F1 included lipopeptides such as iturin A and surfactin.

Technology

Lung cancer detection from saliva by using a by immobilized lectin-affinity fluorescent labeling method

A group from Department of Respiratory Medicine, The First Affiliated Hospital of Soochow University, Suzhou, China etc. has reported about lung cancer detection from saliva by using a by immobilized lectin-affinity fluorescent labeling method.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9969232/

Quantification of protein glycosylation in human biofluids such as saliva and urine would be an easiest way to identify underlying pathophysiological changes. In this study, lectins (AAL, UEA-I, and LCA) were used for quantitative analysis of salivary protein fucosylation.

Lectins were first covalently bound to amine-reactive beads, while proteins extracted from saliva were labeled with fluorescein tags. The lectins and fluorescently labeled proteins are incubated, and the fucosylated glycoproteins are bound to the lectin beads. The lectin bound glycoproteins were placed in a 96-well plate, and the fluorescence intensity was measure by a plate reader.

As a result, it was found that the fucosylation of salivary glycoproteins significantly upregulated in lung cancer than in healthy controls and other diseases, and lung cancer salivary fucosylation was proportional to the tumor malignancy reflecting the stage of lung cancer.

Nature, Technology

Changes in IgG glycosylation of primary Sjögren’s syndrome is detected by LCA lectin

A group from Key Laboratory of Rheumatology & Clinical Immunology, Ministry of Education, Beijing, China, etc. has reported about changes in IgG glycosylation of primary Sjögren’s syndrome.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9961092/

Primary Sjögren’s syndrome (PSS) is a systemic autoimmune disease resulting in significant loss of systemic gland secretory function.

Total of 128 serum samples were used for lectin microarray analysis, obtained from 40 PSS patients), 50 primary biliary cholangitis (PBC) patients, and 38 healthy controls who were healthy volunteers.

As a result, it was found that changes in serum IgG glycosylation in PSS increased binding levels of LCA lectin compared to healthy controls and PBC patients.