Year: 2021

A group from MaxPlanck Tandem Group in Plant Microbial Ecology, Universidad del Valle, Cali, Colombia, etc. has reported that the most abundant bacteria and fungi in seedlings rhizobacteria came from their seeds, not the soil.
https://www.frontiersin.org/articles/10.3389/fmicb.2021.737616/full

Until recently, scientists have traditionally believed that all the rhizosphere microbiome “is recruited from the main reservoir of microorganisms present in soil. However, Is it really true?

In this experiment, plants were grown in hermetically sealed jars on sterile sand as a way to observe microbiome development in the absence of any other source of inoculum except seeds.　In this experiment, 18 kinds of plant were evaluated.

Amazingly enough, in this experiment it was confirmed that soil contributes to microbial diversity in the rhizosphere, however the most abundant bacteria and fungi in rhizospheres derive from seeds. Soil significantly increased bacterial diversity in rhizospheres, however, the highest read abundance was of seed-transmitted bacteria. Only an average of 26% of bacterial taxonomic units (OTUs) came from seeds, but these were responsible for an average of 72% of the reads. These OTUs were mostly Proteobacteria of the genera Pantoea, Enterobacter, Pseudomonas, and Massilia, which were observed in seeds or spermospheres and have also been observed associated with a variety of plant seeds.

Compared to bacteria, there was less seed-transmitted fungal diversity in rhizospheres, with only an average of 12%; however, these OTUs tended to become abundant, representing an average of 42% of the reads. Of these seed-transmitted rhizospheric fungi, Fusarium was the most abundant, occurring in all soil-grown rhizospheres, as it did in all spermospheres.

In this experiment, unsterilized seeds were planted in either sterile sand or farm soil inside hermetically sealed jars. The sand was sterilized by autoclaving twice for 20 min at 121°C, and after transfer to glass jars, it was autoclaved a third time for 20 min at 121°C, and the soil was excavated from a fallow cassava field at a CIAT property near Palmira, Colombia.

A group from Department of Biochemistry and Molecular Biology, East Carolina University, Greenville, North Carolina, USA, etc. has reported that changes in N-glycosylation on neuroblastoma affect on cell proliferation and invasion.
https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0259743

Two types of neuroblastoma cells were used. One is an ​engineered N-glycosylation mutant cell line with Mgat1 knockdown, NB_1(-Mgat1), expressed solely oligomannose N-glycans, and the other was its parental cell line, NB_1 expressed significant levels of higher order N-glycans, complex and hybrid N-glycans as shown below (GNL and ConA have higher affinity to oligomannose type N-glycans, and E-PHA and L-PHA have higher affinity to complex type N-glycans).

Cell growth was faster in NB_1 cells with complex type N-glycans than in NB_1(-Mgat1) cells without complex type N-glycans. Quantitatively speaking, there was about a 54% decrease in cell proliferation between NB_1(-Mgat1) cells and NB_1 cells.

NB_1(-Mgat1) cells had more and longer protrusions than NB_1 cells, indicating that the glycosylation mutant cells solely expressing oligomannose type N-glycans were more invasive than those expressing complex types of N-glycans. To quantify cell invasiveness, the ratio of measured invasive area to the measured sphere area was measured. The cell invasiveness of the NB_1(-Mgat1) cell line was 2.3-fold greater than the NB_1 cell line.

A group from Pritzker School for Molecular Engineering, University of Chicago, Chicago, Illinois, USA, etc. has reported that auto-antibodies against AngII were developed with SARS-CoV-2 infection.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8575143/

Surprisingly, it was found that a substantial proportion, 63% (73/115), of the COVID-19 patients had positive levels of anti-AngII autoantibodies, where 115 were hospitalized COVID-19 patients convalescent from a SARS-CoV-2 infection.

First, it was pointed out that the levels of anti-AngII were significantly higher in patients with dysregulated blood pressure as shown below.

Further, the effect of anti-AngII autoantibodies on oximetric saturation (SF ratio) was measured. The lowest daily mean SF ratio was compared between the COVID-19 patients who developed auto-antibodies against AngII (73 patients) and those who did not (42 patients) as shown below.

It was considered that SARS-CoV-2 and AngII to ACE-2 might lead to their co-phagocytosis by antigenpresenting cells, thus providing a strong immune adjuvant (the virus molecules) to the self-peptide AngII, leading to an anti-AngII autoimmune response.

A group from Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA, etc. has reported that SARS-CoV-2 specific antibody transfer to breastmilk is dominated by IgA and IgM.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8531199/

Previous studies clearly illustrated the evolution and transfer of Fc-effector function in pregnant women via placenta to their infants, but less is known about the transfer of Fc-effector function across breastmilk.

As expected, mothers infected with SARS-CoV-2 possessed SARS-CoV-2-specific antibodies in serum and breastmilk that were not present in SARS-CoV-2-uninfected specimens. But, interestingly, robust transfer of IgA and IgM was observed in breastmilk, but the transfer of IgG1 was more limited as shown below.

A group from University of Liège‐Gembloux Agro‐Bio Tech, Gembloux, Belgium, etc. has reported Bacillus velezensis recognizes plant root cell pectin and thereby improve symbiotic relation.
https://pubmed.ncbi.nlm.nih.gov/34724831/

Molecular interactions driving the early steps of partnership establishment between plant roots and rhizobacteria are not yet fully understood. Authors have found that Bacillus velezensis, one of beneficial bacteria, recognizes plant root cell wall pectin in synergy with soluble root exudates, and thereby the bacterium stimulates the production of a specific surfactin-type lipopeptide as key components of its secretome to improve the partnership in the course of early colonization.

Actually, an 8-fold increase of the surfactin production was detected at the early exponential growth phase with homogalacturonan low methylated (HGLM) as shown below, however, the bacteria seem not to recognize oligomers with a lower polymerization degree (DP) than HGLM, as is clear from the fact that oligogalacturonides (OGs) did not stimulate surfactin biosynthesis. This might mean that longer polymers could indicate a healthy host suitable for bacterial colonization, while the monomers or low DP oligomers may reflect a dead or infected plant that is unable to adequately provide resources to the bacteria.

homogalacturonan low methylated (HGLM), DP of >150; oligogalacturonides (OG), DP of 15; galacturonic acid (GA), DP of 1; where REM means a root exudates mimicking medium.

But, there is no information about a lectin-like protein on the bacteria which can recognize the pectin backbone as a plant molecular pattern was not mentioned here anything.