Abstract: Thus this invention relates to a nanoparticle, useful for bioaffinity assays. The nanoparticle has a self-assembling shell built up of several protein and/or peptide subunits, which protein and/or peptide subunits can be of one or several different types, assembled in an organized manner to form the shell having an inner surface facing the inside and an outer surface facing the outside of said particle. One or several of the types of subunits have one or several first binding moieties per type of subunit with the binding moiety facing the outside of the particle for binding of any specific ligand binding protein; and the particle contains within its shell a marker and/or one or several of the types of subunits have one or several second binding moieties per type of subunit with the binding moiety facing the inside and/or the outside of the particle for binding a marker; and the marker or markers enables detection of the particle.

Abstract: Thus this invention relates to a nanoparticle, useful for bioaffinity assays. The nanoparticle has a self-assembling shell built up of several protein and/or peptide subunits, which protein and/or peptide subunits can be of one or several different types, assembled in an organized manner to form the shell having an inner surface facing the inside and an outer surface facing the outside of said particle. One or several of the types of subunits have one or several first binding moieties per type of subunit with the binding moiety facing the outside of the particle for binding of any specific ligand binding protein; and the particle contains within its shell a marker and/or one or several of the types of subunits have one or several second binding moieties per type of subunit with the binding moiety facing the inside and/or the outside of the particle for binding a marker; and the marker or markers enables detection of the particle.

Abstract: The invention is a method of assessing growth and death rates of micro-organisms within a time period environment of interest. Two reporter genes coding for luminescent and/or fluorescent products introduced into the micro-organism produce at least two products which luminesce or fluoresce. They include, either an essentially stable product produced in an essentially known proportion to the total amount of cells of the micro-organism that are or have been alive within a time period, a product present in an essentially known proportion to the amount of cells alive at any moment within the time period, or an essentially stable product produced in an essentially known proportion to the total amount of cells of the micro-organism that have died within the time period. The micro-organism is incubated and luminescence and/or fluorescence is detected after at time period. Finally, the growth and death rates of the micro-organism are assessed.

Abstract: The invention relates to a method for determining a metal present in a sample, in which methoda) a recombinant DNA plasmid the copy number of which is under the control of a promoter regulatable by the metal is transferred into the cell, or a recombinant DNA plasmid the copy number of which can be varied between 1 and 2000/cell is transferred into the cell, and the plasmid contains as a marker protein a DNA sequence coding for a virus, procaryotic cell or eucaryotic cell protein or for a portion thereof essential for its biological activity, the expression of the DNA sequence being under the control of a promoter regulatable by the metal and being controlled by negative and/or positive feedback;b) the cell containing the recombinant DNA plasmid is contacted with a metal-containing sample;c) the metal is allowed to affect for a suitable time the cell which contains the recombinant DNA plasmid, whereafter the amount of recombinant DNA plasmid or the amount of protein encoded by it is determined by either physic