Genes encoding

The field of DNA vaccination started when eukaryotic expression vectors were injected into the muscle of laboratory animals [2]. The authors observed protein expression for more than 2 months after injection and noted that no special delivery system was required to obtain this expression. Subsequently, it was demonstrated that antibodies can be induced simply by injecting plasmid DNA into the muscle of mice [3]. Subsequent studies found that the injection of expression plasmids also leads to the induction of a cytotoxic T-cell response. After injection, the DNA enters cells of the vaccinated host and the encoded gene becomes expressed. This eventually leads to the induction of a cellular cytotoxic T-cell, T-helper, and/or humoral (antibody) immune response. 

P-Lactamases are enzymes that hydrolyze the P-lactam ring of P-lactamantibiotics (penicillins, cephalosporins, monobactams and carbapenems). They are the most common cause of P-lactam resistance. Most enzymes use a serine residue in the active site that attacks the P-lactam-amid carbonyl group. The covalently formed acylester is then hydrolyzed to reactivate the P-lacta-mase and liberates the inactivated antibiotic. Metallo P-lactamases use Zn(II) bound water for hydrolysis of the P-lactam bond. P-Lactamases constitute a heterogeneous group of enzymes with differences in molecular structures, in substrate preferences and in the genetic localizations of the encoding gene (Table 1). 

Izumi, R., Yamada, T., Yoshikai, S., Sasaki, H., Hattori, M., Sakaki, Y. (1992). Positive and negative regulatory elements for the expression of the Alzheimer s disease amyloid precursor-encoding gene in mouse. Gene 112, 189-195. 

Figure 1. Organisation of the region surrounding pectate lyase encoding genes in E. chrysanthemi 3937 (A) and in E. carotovora ssp. atroseptica (B).

Transcriptionnal activity of pel genes responds differentially to catabolic repression, growth phase, temperature and nitrogen starvation. Iron limitation proved to be involved in the induction of severd of the pectinase encoding genes [7]. 

Van der Meer JR, ARW van Neerven, EJ de Vries, WM de Vos, AJB Zehnder (1991) Cloning and characterization of plasmid-encoding genes for the degradation of 1,2-dichloro-, 1,4-dichloro-, and 1,2,4-trichlo-robenzene of Pseudomonas sp. strain P51. J Bacterial 173 6-15. 

Neumann A, G Wohlfarth, G Diekert (1998) Tetrachloroethene dehalogenase from Dehalospirillum multivorans. cloning, sequencing of the encoding genes, and expression of the pceA gene in Escherichia coli. J Bacterial 180 4140-4145. 

Haak B, S Fetzner, F Lingens (1995) Cloning, nucleotide sequence, and expression of the plasmid-encoded genes for the two-component 2-halobenzoate 1,2-dioxygenase from Pseudomonas cepacia 2CBS. J Bacterial Yll 667-675. 

Lloyd-Jones G, PCK Lau (1997) Glutathione 5-transferase-encoding gene as a potential probe for environmental bacterial isolates capable of degrading polycyclic aromatic hydrocarbons. Appl Environ Microbiol 63 3286-3290. 

Porter, S., and Mintz, B. (1991). Multiple alternatively spliced transcripts of the mouse tyrosinase-encoding gene. Gene 97 277-282. 

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