Abstract: In one aspect, the invention relates to an immunogenic composition that includes a mutant Clostridium difficile toxin A and/or a mutant Clostridium difficile toxin B. The mutant toxin may include a glucosyltransferase domain having at least one mutation and a cysteine protease domain having at least one mutation, relative to the corresponding wild-type C. difficile toxin. The mutant toxins may include at least one amino acid that is chemically crosslinked. In another aspect, the invention relates to methods and compositions for use in culturing Clostridium difficile and in producing C. difficile toxins.

Abstract: Described is a disposable valve that includes an actuation layer operationally linked to a flexible diaphragm; a valving layer operationally linked to the flexible diaphragm; and a connection layer operationally connected to the valving layer; wherein the valving layer and the connection layer have a corresponding plurality of channels passing therethrough, and the channels define at least one fluid flow path, and the flexible diaphragm is movable between a first open position wherein fluid can flow through the fluid flow path, and a second closed position wherein fluid cannot flow through the fluid flow path. Chromatographic systems incorporating a plurality of such valves, optionally integrated into a unitary valve block, are also described.

Abstract: An adsorbent bed is loaded into an HPLC column by a method which comprises fluidization of the adsorbent. The adsorbent may be added as a slurry which is then fluidized and not allowed to settle. The adsorbent bed is then immediately compressed.

Abstract: The adsorbent bed (25) retained in an HPLC column (1) is maintained in a constant state of compression by a spring loaded hydraulically active second column (13). A relatively small spring (14) loaded piston (15) in the second column maintains a constant hydraulic pressure in the hydraulic chamber (3) of the larger diameter HPLC column (1). Multiple small diameter columns (13) can be employed if necessary.

Abstract: Various chemicals such as pharmaceuticals and petrochemicals are chromatographically separated in small quantities using an apparatus comprising a number of serially connected adsorbent-containing chambers. The chambers are linked together with valving necessary to simulate the continuous countercurrent flow of the adsorbent and liquid phases. The apparatus employs three three-port valves per chamber to direct liquid flow. Pressure pairing of the valves and the four major process streams protects product purity.

Abstract: Various chemicals such as pharmaceuticals and petrochemicals are chromatographically separated in small quantities using an apparatus comprising a number of serially connected adsorbent-containing chambers. The chambers are linked together with valving necessary to simulate the continuous countercurrent flow of the adsorbent and liquid phases. The apparatus employs three three-port valves per chamber to direct liquid flow. Pressure pairing of the valves and the four major process streams protects product purity.