20a capsular ps  (ATCC)

Journal: Microbiology Spectrum

Article Title: New pneumococcal serotype 20C is a WciG O-acetyltransferase deficient variant of canonical serotype 20B

doi: 10.1128/spectrum.02443-24

Figure Lengend Snippet: Capsule synthesis loci and capsule polysaccharide structures of serogroup 20 subtypes. ( A ) Representative cps loci of serotypes 20A and 20B. Highly conserved regulatory genes (light gray arrows), genes encoding glycosyltransferases (blue arrows), Wzy polymerases (green arrows), Wzx flippases (pink arrows), O-acetyltransferases (red arrows), carbohydrate synthetases (dark gray arrows), transposable elements (black arrows) are labeled at the top of 20A cps locus. Same gene annotation is followed for the 20B cps locus. White color cross on the whaF gene arrow in the 20A cps locus indicates that this gene is defective. cps , capsule synthesis locus. ( B ) Symbol nomenclature for glycans diagrams of elucidated serotypes 20A and 20B PS repeat unit structures. cps -encoded glycosyltransferase, O-acetyltransferases, and polymerase are listed in blue, red, and green text, respectively, on top of their putatively assigned linkages. ( C ) Alignment of WciG amino acid sequences showing substitutions and translational defects at different residues. The alignment shows WciG sequences of serotype 20A (ATCC6320), serotype 20B (CDC5931-06), and WciG variants (MNK0184 and MNK0952). The numbers on the top of the alignment refer to the amino acid position. Symbol (*) indicates the stop codon. Dots refer to conserved amino acids in reference to the ATCC6320 WciG sequence.

Article Snippet: For capsule PS detection, the ELISA plates (Corning Costar Corp., Acton, MA) were coated with 1 μg/mL of commercially available 20A capsular PS (ATCC, 209-X, ID 950121).

Techniques: Labeling, Sequencing

Journal: Microbiology Spectrum

Article Title: New pneumococcal serotype 20C is a WciG O-acetyltransferase deficient variant of canonical serotype 20B

doi: 10.1128/spectrum.02443-24

Figure Lengend Snippet: Biochemical analysis of capsule polysaccharide produced by serogroup 20 WciG variants. ( A ) 1 H NMR spectra of native capsule PS purified from strains of serotype 20A (ATCC6320), 20B (CDC5931-06), 20C (MNK0184 and MNK0952). Acetylation peaks in the O-acetyl methyl region are labeled (chemical shift: 2.05–2.25 ppm), and O-acetylation of terminal galactofuranose (tGal f ) is labeled in blue letters. Asterisk denotes a signal arising from the cell wall polysaccharide (CWPS). Strain name is provided on the left of the spectra and the corresponding serotype is in parenthesis. ( B ) cps locus of serotypes 20C. The gene annotation is followed as described for 20A and 20B cps loci in . White color cross on the wciG gene arrow in the 20C cps locus indicates that this gene is defective. ( C ) Symbol nomenclature for glycans diagrams of elucidated serotype 20C PS repeat unit structure. cps -encoded glycosyltransferase, O-acetyltransferases, and polymerase are listed in blue, red, and green text, respectively, on top of their putatively assigned linkages. The symbol key is found in .

Article Snippet: For capsule PS detection, the ELISA plates (Corning Costar Corp., Acton, MA) were coated with 1 μg/mL of commercially available 20A capsular PS (ATCC, 209-X, ID 950121).

Techniques: Produced, Purification, Labeling

Journal: Microbiology Spectrum

Article Title: New pneumococcal serotype 20C is a WciG O-acetyltransferase deficient variant of canonical serotype 20B

doi: 10.1128/spectrum.02443-24

Figure Lengend Snippet: Serological properties of serogroup 20 subtypes. ( A ) FCSA histograms depicting antibody deposition on strains ATCC6320 (20A), CDC5931-06 (20B), MNK0184 (20C), JY21 (20C), and SPEC6B (serotype 6B, control strain). Black curves represent the fluorescence of bacteria incubated in different antisera (bottom labels), while gray-filled curves represent negative-control preparations incubated with secondary antibodies only. Hyp6BG13 and Hyp20G5 represent monoclonal antibodies (Mabs) specific to serotype 6B and serogroup 20, respectively. Type-20 antiserum and factor serum 20b are the polyclonal rabbit antisera. ( B ) Minimized molecular models for 6RU of 20A (left), 20B (middle), and 20C (right), shown in space-filling representation and colored according to residue type. The models show the same extended helical conformation with 2RU per helical turn for the three serotypes. ( C ) Inhibition enzyme-linked immunosorbent assay (ELISA) illustrates the ability of purified 20A, 20B, and 20C capsule PS to inhibit the binding of Hyp20G5. 20A capsule PS was commercially obtained from ATCC. 20B and 20C capsule PS were purified from CDC5931-06 and MNK0184 strains, respectively. The Y-axis shows the antibody (Hyp20G5) bound to ELISA plates coated with 20A PS, while the X-axis displays different inhibitory concentrations of purified capsule PS. ( D ) Reactivity of purified 20A, 20B, and 20C capsule PS with the anthrone reagent. Y-axis represents the absorbance at OD 630 , indicating the strength of reactivity, and X-axis shows different PS dilutions (twofold serial dilutions) used to react with the anthrone reagent. Average OD values from quadruplets are plotted. ( E ) Opsonic titers against target strains ATCC6320 (20A), CDC5931-06 (20B), MNK0184 (20C) using postimmunization PPSV23 sera samples from four human adults (P007B, P008B, P014B, and P016B) and a reference sample (007sp). Data were analyzed by one-way analysis of variance with Tukey’s multiple-comparison test. OPK, opsonophagocytosis killing.

Article Snippet: For capsule PS detection, the ELISA plates (Corning Costar Corp., Acton, MA) were coated with 1 μg/mL of commercially available 20A capsular PS (ATCC, 209-X, ID 950121).

Techniques: Control, Fluorescence, Bacteria, Incubation, Negative Control, Bioprocessing, Residue, Inhibition, Enzyme-linked Immunosorbent Assay, Purification, Binding Assay, Comparison