Abstract: Disclosed are (1) a DNA sequence encoding a mutant L3T4 protein which, when expressed on the surface of a cell, is capable of facilitating infection of the cell by human immunodeficiency virus; the mutant protein includes at least one amino acid residue substitution or deletion in a segment corresponding to the gp120 binding epitope of a native L3T4 protein so as to increase homology between that segment and its counterpart in a CD4 protein; (2) a murine cell line or strain transfected with such a DNA sequence; and (3) a transgenic mouse susceptible to infection by human immunodeficiency virus.

Abstract: The present invention relates to a tetracycline repressor-mediated binary regulation system for the control of gene expression in transgenic mice. It is based, at least in part, on the discovery that, in a transgenic mouse that carries a first transgene under the control of a modified promoter comprising a tetR operator sequence and a second transgene encoding the tetR protein, expression of the first transgene may be efficiently induced by administering tetracycline to the mouse.

Abstract: The present invention relates to a method for the controlled expression, in a lactic acid bacterium, of a DNA fragment containing one or more genes coding for a desired characteristic, wherein the DNA fragment is under the control of a promoter for a microbial gene which codes for an antimicrobial peptide, and the gene or genes are brought to expression on the DNA fragment by the addition of a suitable inducing factor for the transcription activation. The promoter is preferably the nisA promoter from Lactococcus lactis. The inducer is preferably acceptable for food products, and more preferentially is nisin or derivatives thereof. The invention also relates to a method for the production of proteins or RNA, as well as to a method for the preparation of dairy products using the expression system according to the invention. The invention finally relates to lactic acid bacteria and expression vectors for use in the method according to the invention.

Abstract: A portable, hand-held reader reads a symbol associated with a product selected by a customer. A database of a host computer stores attribute data of many products. The database is accessed on a real-time basis to automatically retrieve the stored product attribute data. The retrieved data is displayed on a display associated with the reader. A card reading device is provided on the hand-held reader, for charging a customer's account, all at one location. A printer prints a written memorandum of the transaction.

Abstract: A gene activation/inactivation and site-specific integration system has been developed for mammalian cells. The invention system is based on the recombination of transfected sequences by FLP, a recombinase derived from Saccharomyces. In several cell lines, FLP has been shown to rapidly and precisely recombine copies of its specific target sequence. For example, a chromosomally integrated, silent .beta.-galactosidase reporter gene was activated for expression by FLP-mediated removal of intervening sequences to generate clones of marked cells. Alternatively, the reverse reaction can be used to target transfected DNA to specific chromosomal sites. These results demonstrate that FLP can be used, for example, to mosaically activate or inactivate transgenes for a variety of therapeutic purposes, as well as for analysis of vertebriate development.

Abstract: The invention provides methods and compositions for evaluating modulators of the Stat6 signaling pathway; in a particular, transgenic mice comprising a transgene within a Stat6 allele locus, encoding a selectable marker and displacing the SH2-encoding domain of the Stat6 allele. More particularly, the transgene may comprise 3' and 5' regions with sufficient complementarity to the natural Stat6 allele at the locus to effect homologous recombination of the transgene with the Stat6 allele. Such mice provide useful animal models for determining the effect of candidate drugs on a host deficient in Stat6 function. The invention provides a variety of methods for making and using the subject compositions; in particular, methods for determining the effect of a candidate drug on a mouse deficient in Stat6 function and methods of evaluating the side effects of a Stat6 function inhibitor.