Journal: bioRxiv

Article Title: Rhamnose biosynthesis is not impaired by the deletion of putative rfbC genes , slr0985 and slr1933 , in Synechocystis sp. PCC 6803

doi: 10.1101/2025.03.27.645739

Figure Lengend Snippet: Biosynthetic pathways and genomic context of genes involved in the synthesis of fucose and rhamnose in Synechocystis sp. PCC 6803. (A) Schematic representation of the putative biosynthetic pathways of guanosine diphosphate-L-fucose (GDP-Fuc) and deoxythymidine diphosphate-L-rhamnose (dTDP-Rha). The red line indicates feed-back inhibition. (B) Locus of the genes encoding enzymes putatively involved in the biosynthetic pathways of GDP-Fuc and dTDP-Rha, with the genes knockout in this study highlighted in red, blue and green. Both the locus tag and gene name/symbol(s) are provided when available. Unk./Hyp. - genes encoding unknown or hypothetical proteins.

Article Snippet: The cyanobacterium Synechocystis sp. PCC 6803 wild type (sub-strain GT-Kazusa; glucose tolerant, with S-layer and non-motile) and strains were cultivated in BG11 medium ( ) at 30 °C under a 12 h light (25 μmol photons m −2 s −1 )/12 h dark regimen with orbital shaking (150 rpm).

Techniques: Inhibition, Knock-Out

Journal: bioRxiv

Article Title: Rhamnose biosynthesis is not impaired by the deletion of putative rfbC genes , slr0985 and slr1933 , in Synechocystis sp. PCC 6803

doi: 10.1101/2025.03.27.645739

Figure Lengend Snippet: Aggregation/sedimentation and cell wall ultrastructure of Synechocystis sp. PCC 6803 wild type (WT), and Δ fucS , Δ rfbC1 and Δ rfbC1 Δ rfbC2 strains. (A) Micrographs of the strains at low cell densities highlighting the clumping phenotype of Δ fucS , scale bar: 20 μm. Inserts highlight differences in sedimentation. (B) Sedimentation index (%) at 0, 24 and 48 h. Data represent means ± SD ( n = 3). (C) Ultrastructure of the cell wall with the S-layer highlighted (arrow) and insert with the putative detached S-layer in Δ fucS also highlighted (asterisk). Scale bars: 200 nm. Cells were grown in BG11 medium at 30 °C under a 12 h light (25 μE m −2 s −1 )/12 h dark regimen, with orbital shaking at 150 rpm.

Article Snippet: The cyanobacterium Synechocystis sp. PCC 6803 wild type (sub-strain GT-Kazusa; glucose tolerant, with S-layer and non-motile) and strains were cultivated in BG11 medium ( ) at 30 °C under a 12 h light (25 μmol photons m −2 s −1 )/12 h dark regimen with orbital shaking (150 rpm).

Techniques: Sedimentation

Journal: bioRxiv

Article Title: Rhamnose biosynthesis is not impaired by the deletion of putative rfbC genes , slr0985 and slr1933 , in Synechocystis sp. PCC 6803

doi: 10.1101/2025.03.27.645739

Figure Lengend Snippet: Growth, total carbohydrates, released polysaccharides and capsular polysaccharides of Synechocystis sp. PCC 6803 wild type (WT), and Δ fucS , Δ rfbC1 and Δ rfbC1 Δ rfbC2 strains. (A) Growth (optical density at 730 nm) and μg of chlorophyll a per mL of culture, (B) production of total carbohydrates (C), released polysaccharides, and (D) capsular polysaccharides expressed as μg of carbohydrates per μg of chlorophyll a . Data represent means ± SD ( n ≥ 3) and individual measurements are shown. Statistical analysis performed using one-way analysis of variance (ANOVA), followed by Dunnett’s multiple comparisons, is shown for the last time point. Significant differences are identified: *( p ≤ 0.05), **( p ≤ 0.01), ***( p ≤ 0.001), ****( p ≤ 0.0001).

Article Snippet: The cyanobacterium Synechocystis sp. PCC 6803 wild type (sub-strain GT-Kazusa; glucose tolerant, with S-layer and non-motile) and strains were cultivated in BG11 medium ( ) at 30 °C under a 12 h light (25 μmol photons m −2 s −1 )/12 h dark regimen with orbital shaking (150 rpm).

Techniques:

Journal: bioRxiv

Article Title: Rhamnose biosynthesis is not impaired by the deletion of putative rfbC genes , slr0985 and slr1933 , in Synechocystis sp. PCC 6803

doi: 10.1101/2025.03.27.645739

Figure Lengend Snippet:

Article Snippet: The cyanobacterium Synechocystis sp. PCC 6803 wild type (sub-strain GT-Kazusa; glucose tolerant, with S-layer and non-motile) and strains were cultivated in BG11 medium ( ) at 30 °C under a 12 h light (25 μmol photons m −2 s −1 )/12 h dark regimen with orbital shaking (150 rpm).

Techniques:

Journal: bioRxiv

Article Title: Rhamnose biosynthesis is not impaired by the deletion of putative rfbC genes , slr0985 and slr1933 , in Synechocystis sp. PCC 6803

doi: 10.1101/2025.03.27.645739

Figure Lengend Snippet: Detection of rhamnose on the cells surface of Synechocystis sp. PCC 6803 wild type (WT), and Δ fucS , Δ rfbC1 and Δ rfbC1 Δ rfbC2 strains using a rhamnose binding protein tagged with GFP (gp17-GFP). (A) Micrographs depicting the red autofluorescence signal and the green signal from the gp17-GFP. The right panels show the merging of the other two micrographs. Scale bar: 10 μm. (B) Quantification of fluorescence associated with gp17-GFP bound to rhamnose at the surface of the cells. Data represents means ± SD ( n = 3) and individual measurements are shown. Statistical analysis consists of one-way analysis of variance (ANOVA), followed by Dunnett’s multiple comparisons. Significant differences are identified: **( p ≤ 0.01) and ****( p ≤ 0.0001).

Article Snippet: The cyanobacterium Synechocystis sp. PCC 6803 wild type (sub-strain GT-Kazusa; glucose tolerant, with S-layer and non-motile) and strains were cultivated in BG11 medium ( ) at 30 °C under a 12 h light (25 μmol photons m −2 s −1 )/12 h dark regimen with orbital shaking (150 rpm).

Techniques: Binding Assay, Fluorescence

Journal: bioRxiv

Article Title: Rhamnose biosynthesis is not impaired by the deletion of putative rfbC genes , slr0985 and slr1933 , in Synechocystis sp. PCC 6803

doi: 10.1101/2025.03.27.645739

Figure Lengend Snippet: Analysis of the relative normalised expression of genes putatively related to the biosynthesis of deoxyhexoses and EPS in Synechocystis sp. PCC 6803 wild type (WT) and Δ fucS , Δ rfbC1 and Δ rfbC1 Δ rfbC2 strains. RNA was extracted from cells of the different strains collected at three time points: 0, 7 and 21 days. RT-qPCR analysis of (A) gmd ( slr1072 ), rfbC1 ( slr0985 ) and rfbC2 ( slr1933 ) expression in Synechocystis sp. PCC 6803 wild type and Δ fucS ; (B) rfbB ( slr0982 ), rfbF ( slr0983 ), slr1610 (putative methyltransferase), gmd ( slr1072 ), fucS ( sll1213 ) and slr1933 ( rfbC2 ) expression in wild type and Δ rfbC1 ; and (C) rfbB ( slr0982 ), rfbF ( slr0983 ), slr1610 (putative methyltransferase), gmd ( slr1072 ) and fucS ( sll1213 ) expression in wild type and Δ rfbC1 Δ rfbC2 . The normalised fold expression of the target genes relative to wild type is represented at each time point. Data from three biological and three technical replicates were normalised against two reference genes ( sll1212 and sll1395 ), and error bars represent the standard deviations. Statistical analysis was performed using t -test, and significant differences are identified: *( p ≤ 0.05), **( p ≤ 0.01), ***( p ≤ 0.001), ****( p ≤ 0.0001).

Article Snippet: The cyanobacterium Synechocystis sp. PCC 6803 wild type (sub-strain GT-Kazusa; glucose tolerant, with S-layer and non-motile) and strains were cultivated in BG11 medium ( ) at 30 °C under a 12 h light (25 μmol photons m −2 s −1 )/12 h dark regimen with orbital shaking (150 rpm).

Techniques: Expressing, Quantitative RT-PCR