1. A multifunctional Escherichia coli-Streptomyces sp. conjugative shuttle vector designated as pGTR760 containing multiple cloning sites.
2. A recombinant Escherichia coli-Streptomyces conjugative shuttle vector pCAB218 cloned with a nucleic acid sequence coding for genes responsible for polyhydroxyalkanoate synthesis.
3. A biologically pure culture of recombinant Streptomyces lividans TK64 bearing ATCC No. PTA 1578, said bacterium harbouring pCAB218 plasmid and capable of producing polyhydroxyoctanoate (PHO) in substantial amounts.
4. A process for the production of polyhydroxyoctanoate, said method comprising the steps of:
a) constructing a multifunctional Escherichia coli-Streptomyces sp. conjugative shuttle vector designated as pGTR760,
b) cloning of the polyhydroxyalkanoate biosynthesis operon phaCABRe from Ralstonia eutropha in pUC18 plasmid vector and recloning of the phaCABRe operon from pUC18 into the pGTR760 vector resulting in the formation of a new conjugative shuttle vector designated as pCAB218,
c) transforming Escherichia coli S17-1 with the plasmid pCAB218 to develop recombinant Escherichia coli S17-1,
d) transforming Escherichia coli S17-1 with Streptomyces lividans TK64 to obtain genetically modified bacterium Streptomyces lividans TK64, and
e) culturing the genetically modified Streptomyces lividans TK64 in a conventional medium and recovering polyhydroxyoctanoate (PHO).
5. A process as claimed in claim 4 wherein the multifunctional conjugative shuttle vector pGTR760 is developed by ligating a 760 bp Ori T PstI restriction fragment from plasmid pPM801 with plasmid pUWL218 at a temperature in the range of 14-16 C. in the presence of T4 DNA ligase enzyme for a period ranging between 16 to 18 hours.
6. A process as claimed in claim 4 wherein the multifunctional Escherichia coli-Streptomyces species conjugative shuttle vector pCAB218 is developed by cloning the polyhydroxyalkanoate synthesis operon phaCABRe obtained from Ralstonia eutropha into the EcoRI-BamHI restriction sites of the vector pGTR760.
7. A process as claimed in claim 4 wherein the medium comprises glycerol, asparagine and salts.
8. A process as claimed in claim 4 wherein the medium comprises glycerol, L-aspargine, distilled water and salts selected from anhydrous K2HPO4, FeSO4.7H2O, MnCl2.4H2O and ZrSO4.7H2O.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A scanner system comprising a radiation generator arranged to generate radiation to irradiate an object, a detector structure arranged to detect the radiation after it has interacted with the object and generate a sequence of detector data sets as the object is moved relative to the generator, and a processor arranged to process each of the detector data sets thereby to generate a control output arranged to control the radiation generator to vary its radiation output as the object is scanned.
2. A scanner system according to claim 1 wherein the processor is arranged to define a parameter of the detector data, to determine a value of the parameter for each data set, and generate a control output arranged to vary the radiation output if the value of the parameter does not meet a predetermined condition.
3. A scanner according to claim 1 wherein the detector structure comprises a plurality of detectors and the detector data comprises a set of intensity values indicative of the intensity of radiation at each of the detectors.
4. A scanner system according to claim 1 wherein the control output is arranged to control the energy of the radiation.
5. A scanner system according to claim 1 wherein the control output is arranged to control a dimension of the radiation beam.
6. A scanner system according to claim 1 wherein the radiation generator is arranged to generate the radiation in pulses and the control output is arranged to control at least one of the duration and the frequency of the pulses.
7. A scanner system according to claim 1 wherein the radiation generator comprises an adjustable collimator and the control input is arranged to adjust the collimator in response to the control input.
8. A scanner system according to claim 7 wherein the collimator has a varying thickness so that adjustment of the collimator can adjust the energy of the radiation beam.
9. A scanner system according to claim 7 wherein the collimator comprises a plurality of collimator elements each of which can be adjusted independently so as to vary different respective parts of the radiation beam.
10. A scanner system according to claim 1 wherein the radiation generator comprises a collimator and the control input is arranged to generate the radiation as a beam and to vary the position of the beam in response to the control input thereby to vary the proportion of the beam that is blocked by the collimator.
11. A scanner system according to claim 1 wherein the radiation generator comprises an electron source arranged to direct a beam of electrons towards a target, and is arranged to adjust the electron beam in response to the control input.
12. A scanner system according to claim 11 wherein the radiation generator includes a scraper arranged to block a variable proportion of the electrons in the beam.
13. A scanner system according to claim 12 wherein the radiation generator is arranged to generate a magnetic field and to direct the electron beam through the magnetic field so that it turns, and wherein the magnetic field is variable to vary the proportion of the electrons which are blocked.
14. A scanner system according to claim 11 wherein the radiation generator is arranged to generate a variable magnetic field and to vary the magnetic field so as to vary focusing of the electron beam.
15. A scanner system according to claim 1 wherein the processor is arranged to adjust the detector data to compensate at least partially for the controlled variation of the radiation output.
16. A scanner system according to claim 1 wherein the radiation generator and the detection structure are supported on a rotatable gantry which is arranged to rotate as each data set is collected.