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This review summarizes the recent advances concerning metal-organic frameworks (MOFs) modified with several biomolecules (e.g., amino acids, nucleobases, proteins, antibodies, aptamers, etc.) as ligands to prepare affinity-based sorbents for application in the sample preparation field. The preparation and incorporation strategies of these MOF-based affinity materials were described. Additionally, the different types of ligands that can be employed for the synthesis of these biocomposites and their application as sorbents for the selective extraction of molecules and clean-up of complex real samples is reported. The most important features of the developed biocomposites will be discussed throughout the text in different sections, and several examples will be also commented on in detail.

Jablon, James M. (National Children's Cardiac Hospital, Miami, Fla.), Betty Brust, and Milton S. Saslaw. beta-Hemolytic streptococci with group A and type II carbohydrate antigens. J. Bacteriol. 89:529-534. 1965.-Ten strains of beta-hemolytic streptococci with unusual somatic antigens were isolated from excised tonsils or throat cultures or both. Acid extracts of these strains reacted with commercial group A and group F antisera, but gave no reaction when tested with 35 type-specific group A antisera. Serum cross-absorption and agar-gel diffusion studies established the identity of the reactive antigens as the specific carbohydrates of group A and of type II. The latter antigen has been found in many strains of group F streptococci. The organisms do not possess the group-specific carbohydrate of group F, and the reaction with the commercial group F antiserum is due to the presence of type II antibody in the antiserum. The organisms give a stronger reaction to fluorescein-conjugated type II antiserum than to group A. However, the organisms have only one group-specific carbohydrate, that of group A, and, tentatively, should be classified as such.

The trypsinized cell walls of Group C hemolytic streptococci are composed of the specific carbohydrate antigen and a mucopeptide matrix. Certain phage resistant strains of Group C streptococci, isolated from organisms which survive exposure to Group C bacteriophage also possess carbohydrate and mucopeptide fractions, but the carbohydrate gives a precipitin reaction with Group A-variant antiserum and not with Group C antiserum. These strains have been termed Group C-variant. The C-variant carbohydrate contains 86 per cent rhamnose and only 2 per cent galactosamine, and is thus chemically and immunologically similar to Group A-variant carbohydrate. The evidence suggests that the antigenic determinants of Groups A-variant and C-variant carbohydrates are rhamnose-rhamnose linkages. These results strongly support the hypothesis that the carbohydrates of Groups A and C streptococci are composed of a similar rhamnose moiety but that the determinant amino sugar terminal to the rhamnose-rhamnose linkages in the case of Group A is N-acetylglucosamine whereas that of Group C is N-acetylgalactosamine.

Georg, Lucille K. (Communicable Disease Center, Atlanta, Ga.), Gordon W. Robertstad, and Sherry A. Brinkman. Identification of species of Actinomyces. J. Bacteriol. 88:477-490. 1964.-Four unusual isolates of Actinomyces species were compared with six control strains of well-identified Actinomyces species. Their oxygen requirements and their morphological and biochemical characteristics were determined. Final identifications were confirmed by cell-wall analyses for amino acid and carbohydrate composition and by agar-gel techniques. Two strains, A-13-R and A-13-S, isolated from the same cow head were shown to represent rough and smooth variants of A. bovis. The strains were not only morphologically distinct, but had different biochemical reactions and antigenic makeup. The two other strains, X407 and X573, isolated from human pleural fluid and a lung abscess, respectively, were shown to represent a new Actinomyces species.

Extracts of human splenic tissue were found to resemble interferon in (a) their physicochemical properties, and (b) their mode of action when tested in vivo in the rabbit, using vaccinia as the challenge virus. The methods used to obtain (1) the crude extract and (2) a partially purified final fraction are described. The latter was found to be non-dialysable, stable over a pH range of 2-11, and relatively heat resistant. On analysis it appeared to be, or was associated with, a glycoprotein.

Trypsinized cell walls of Group B hemolytic streptococci are composed of a group-specific carbohydrate and mucopeptide. The carbohydrate extracted with hot formamide is composed of rhamnose, N-acetylglucosamine, and galactose. Quantitative precipitin inhibition studies have shown that L rhamose is the significant component of the antigenic determinant. The cross-reactivity between B and G carbohydrates is dependent upon the fact that Lrhamose is a determinant sugar in both antigens.