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S Estrada-Parra

Publications and source records attributed to S Estrada-Parra.

At least 55 records · Page 3Linked to original sources
PubMed1965

Immunochemistry of the Group-Specific Polysaccharide of Nocardia brasiliensis.

Estrada-Parra, Sergio (Escuela Nacional de Ciencias Biológicas, México, D.F., México), Abel Zamora, and L. F. Bojalil. Immunochemistry of the group-specific polysaccharide of Nocardia brasiliensis. J. Bacteriol. 90:571-574. 1965.-The group-specific polysaccharide of Nocardia brasiliensis was further purified, yielding an amorphous white material with the following characteristics: [alpha](D) (20) = + 48; nitrogen, 0.5%; phosphorus, 0.1%; and ash as sodium, 0.8%. The polymer is made of d-arabinose and d-galactose in a molar ratio of 3:1, and no other sugars were detected. Mild hydrolysis liberates mainly arabinose. The polysaccharide consumes 3.46 mumoles of periodate per mg of polymer in 15 days at 4 C (this value remains constant after 4 more days). Oxidation results in destruction of two of the arabinose, with the formation of two glycerols after borohydride reduction and hydrolysis. The polysaccharide oxidized by periodate and reduced under mild acid hydrolysis at 20 C yields glycerol and a polymer formed by galactose and arabinose (in a ratio of 1:1) which is resistant to a second oxidation. Therefore, the polysaccharide is probably formed by a main chain of glactose linked 1,3 and arabinose linked 1,2 or 1,3 or both, and nonreducing side chains of arabofuranose residues. The intact polysaccharide cross-reacts with sera from patients with active tuberculosis, and this, as well as the homologous reaction, is abolished by oxidation with periodate.

Journal Article↗
PubMedDate not supplied

Contributions to the elucidation of S XIV pneumococcal polysaccharide structure.

Rabbits were immunized with a hemocyanin (Hcy)-p-amino phenyl beta lactoside (PAFBLO) conjugate and the gamma globulin fraction from immune sera was purified. Antibodies were demonstrated by means of the quantitative precipitin reaction using an egg albumin (EA)-PAFBLO conjugate as antigen. PAFBLO, D-lactose, D-galactose, cellobiose and D-galacturonic acid were used as inhibitors of the precipitin reaction and their relative affinity constants were calculated. The best inhibitors were the homologous hapten, D-lactose and D-galactose. Anti PAFBLO antibodies precipitated with types 6, 14 and 18 pneumococcal polysaccharides (SVI, SXIV and SXVIII) probably due to the presence of either D-lactose or D-galactose in similar linkage as in PAFBLO in these polymers. Antibodies also reacted with human red blood cells type B.

Animals↗