Lars Andrup - Academia.edu (original) (raw)
Papers by Lars Andrup
Journal of Bacteriology, 1988
Plasmids carrying the intact Bacillus subtilis dnaA-like gene and two reciprocal hybrids between ... more Plasmids carrying the intact Bacillus subtilis dnaA-like gene and two reciprocal hybrids between the B. subtilis and Escherichia coli dnaA genes were constructed. None of the plasmids could transform wild-type E. coli cells unless the cells contained surplus E. coli DnaA protein (DnaAEc). A dnaA (Ts) strain integratively suppressed by the plasmid R1 origin could be transformed by plasmids carrying either the B. subtilis gene (dnaABs) or a hybrid gene containing the amino terminus of the E. coli gene and the carboxyl terminus of the B. subtilis gene (dnaAEc/Bs). In cells with surplus E. coli DnaA protein, expression of the E. coli dnaA gene was derepressed by the B. subtilis DnaA protein and by the hybrid DnaAEc/Bs protein, whereas it was strongly repressed by the reciprocal hybrid protein DnaABs/Ec. The plasmids carrying the different dnaA genes probably all interfere with initiation of chromosome replication in E. coli by decreasing the E. coli DnaA protein concentration to a limit...
Scandinavian Journal of Work, Environment & Health, 1990
Since no occupational accidents or diseases have been attributed specifically to the use of const... more Since no occupational accidents or diseases have been attributed specifically to the use of constructions containing recombinant deoxyribonucleicacid (rDNA), this paper evaluates the occupational health risks in industries utilizinggenetically manipulated organisms mainly on the basis of theoretical considerations. Bacteria, filamentous fungi, yeasts, and mammalian cellsin culture are in use. For each of these systems the possible hazards are considered. Concerning microbial production systems, infections are regarded as the main problem, but the risk of infection is considered extremely low. As for cells in culture, only dormant viruses are regarded as problematic, but well-defined production cell lines should not contain such undetected and dangerous viruses. Overall, the additional risks posed by rDNA-modified microorganisms are minor. Only long-term observations can, however, confirm this assumption, and consequently the highest feasible containment measures should still be used in the years to come.
Microbiology, 2005
... J Clin Pathol 29, 938940.[Abstract/Free Full Text]. Musa, MO, Al Douri, M., Khan, S., Shafi,... more ... J Clin Pathol 29, 938940.[Abstract/Free Full Text]. Musa, MO, Al Douri, M., Khan, S., Shafi, T., Al Humaidh, A. & Al Rasheed, AM (1998). ... Toh, M., Moffitt, MC, Henrichsen, L., Raftery, M., Barrow, K., Cox, JM, Marquis, CP & Neilan, BA (2004). ...
Microbiology, 1999
Detailed functional analysis revealed the modular organization of pGI2, a 9672 bp plasmid from Ba... more Detailed functional analysis revealed the modular organization of pGI2, a 9672 bp plasmid from Bacillus thuringiensis H1.q that harbours the 4149 bp transposon Tn4430. Whereas the pG12 leading-strand replicon was identified through deletion experiments, sequence comparisons indicated the presence of an sso,-like single-strand origin commonly found among Bacillus plasmids. Southern hybridizatkn confirmed the existence of ssDNA intermediates, but only in the case of plasmid derivatives lacking the ssot site. Moreover, the pG12 replication protein Rep displayed significant similarity with that of pTX14-3, a 7 6 kb plasmid from 6. thuringiensis serovar israelensis, suggesting that both elements are representatives of a new family of rolling-circle replicating (RCR) plasmids. In addition, both plasmids share a conserved 320 bp region downstream of their rep genes which, in the case of pG12, appeared indispensable for replication. This region is therefore likely to correspond to, or to be part of, the actual double-strand origin of both plasmids. Another interesting feature of pCl2 is the presence of a mobilization (Mob) protein, as demonstrated by its ability to be mobilized by the conjugative plasmid pAW63 from B. thuringiensis serovar kurstalci HD73. The same transfer system was also used to unambiguously demonstrate similar properties of the related Mob-like protein from pTX14-3. A closer analysis of this family of related Mob proteins suggested a subdomanial organization among its members. Finally, the 270 residue pGl2 ORF2 was shown to be related to ORF43 of pMRCO1, a 60 kb conjugative plasmid from Lactococcus lactis subsp. ladis. Although no function has been assigned to the putative ORF43 protein, it is located downstream of a bacteriocin operon, next to an 15946 element. pG12 appears thus far as an assemblage of functional modules with no obvious metabolic function, presumabty acting as a reservoir of carrier (rep and so), rearrangement (Tn4430) or recruiting (Mob) entities for its bacterial host.
Microbiology, 1999
Quantitative measurements of horizontal DNA transfer are critical if one wishes to address questi... more Quantitative measurements of horizontal DNA transfer are critical if one wishes to address questions relating to ecology, evolution and the safe use of recombinant bacteria. Traditionally, the efficiency of a conjugation system has been described by its transfer frequency. However, transfer frequencies can be determined in many ways and may be sensitive to physical, chemical and biological conditions. In this study the authors have used the mechanistic similarity between bacterial conjugation and simple enzyme catalysis in order to calculate the maximal conjugation rate (V max) and the recipient concentration (K m) at which the conjugation rate is half its maximal value, for two different conjugation systems : the F plasmid from Escherichia coli and plasmid pCF10 from Enterococcus faecalis. The results are compared with the data obtained from the aggregation-mediated conjugation system encoded on pXO16 from Bacillus thuringiensis. The conjugation systems analysed are fundamentally different ; however, they have some characteristics in common : they are able to sustain conjugative transfer in liquid medium and the transfer efficiencies are very high. Conjugation encoded by the F plasmid in E. coli involves the formation of small aggregates (2-20 cells), established by sex pili, and the plasmid's maximal conjugation rate was estimated to be approximately 015 transconjugants per donor per minute. Pheromone-induced conjugation in Ent. faecalis, which involves the formation of large aggregates, was found to proceed at a maximal conjugation rate of 029 transconjugants per donor per minute. Also, the K m value differed significantly between these conjugation systems ; this may reflect the inherent differences in mating pair formation and transfer mechanisms. In these conjugation systems, the donors underwent a ' recovery period ' between rounds of conjugative transfer and newly formed transconjugants required a period of about 40-80 min to mature into proficient donors.
Relation, 2008
Background: Comparative genomics is a powerful means of establishing inter-specific relationships... more Background: Comparative genomics is a powerful means of establishing inter-specific relationships between gene function/location and allows insight into genomic rearrangements, conservation and evolutionary phylogeny. The availability of the complete sequence of the chicken genome has initiated the development of detailed genomic information in other birds including turkey, an agriculturally important species where mapping has hitherto focused on linkage with limited physical information. No molecular study has yet examined conservation of avian microchromosomes, nor differences in copy number variants (CNVs) between birds. Results: We present a detailed comparative cytogenetic map between chicken and turkey based on reciprocal chromosome painting and mapping of 338 chicken BACs to turkey metaphases. Two inter-chromosomal changes (both involving centromeres) and three pericentric inversions have been identified between chicken and turkey; and array CGH identified 16 inter-specific CNVs. Conclusion: This is the first study to combine the modalities of zoo-FISH and array CGH between different avian species. The first insight into the conservation of microchromosomes, the first comparative cytogenetic map of any bird and the first appraisal of CNVs between birds is provided. Results suggest that avian genomes have remained relatively stable during evolution compared to mammalian equivalents.
International Journal of Food Microbiology, 2005
Based on a combination of PCR and restriction endonuclease (RE) digestion (PCR-RE digestion), we ... more Based on a combination of PCR and restriction endonuclease (RE) digestion (PCR-RE digestion), we have examined the possibility of differentiating members of the Bacillus cereus group. Fragments of the gyrB gene (362 bp) from pure cultures of 12 B. cereus, 25 B. thuringiensis, 25 B. mycoides and two B. anthracis strains were amplified and subsequently digested with Sau3A1. Furthermore, a majority of the amplicons were sequenced directly to verify the PCR-RE results. The results obtained suggest that only the B. mycoides generates specific fragments following PCR-RE. Conversely, it was not possible to discriminate between the B. cereus and the B. thuringiensis strains using the methods described.
Journal of Bacteriology, 1988
Plasmids carrying the intact Bacillus subtilis dnaA-like gene and two reciprocal hybrids between ... more Plasmids carrying the intact Bacillus subtilis dnaA-like gene and two reciprocal hybrids between the B. subtilis and Escherichia coli dnaA genes were constructed. None of the plasmids could transform wild-type E. coli cells unless the cells contained surplus E. coli DnaA protein (DnaAEc). A dnaA (Ts) strain integratively suppressed by the plasmid R1 origin could be transformed by plasmids carrying either the B. subtilis gene (dnaABs) or a hybrid gene containing the amino terminus of the E. coli gene and the carboxyl terminus of the B. subtilis gene (dnaAEc/Bs). In cells with surplus E. coli DnaA protein, expression of the E. coli dnaA gene was derepressed by the B. subtilis DnaA protein and by the hybrid DnaAEc/Bs protein, whereas it was strongly repressed by the reciprocal hybrid protein DnaABs/Ec. The plasmids carrying the different dnaA genes probably all interfere with initiation of chromosome replication in E. coli by decreasing the E. coli DnaA protein concentration to a limit...
Scandinavian Journal of Work, Environment & Health, 1990
Since no occupational accidents or diseases have been attributed specifically to the use of const... more Since no occupational accidents or diseases have been attributed specifically to the use of constructions containing recombinant deoxyribonucleicacid (rDNA), this paper evaluates the occupational health risks in industries utilizinggenetically manipulated organisms mainly on the basis of theoretical considerations. Bacteria, filamentous fungi, yeasts, and mammalian cellsin culture are in use. For each of these systems the possible hazards are considered. Concerning microbial production systems, infections are regarded as the main problem, but the risk of infection is considered extremely low. As for cells in culture, only dormant viruses are regarded as problematic, but well-defined production cell lines should not contain such undetected and dangerous viruses. Overall, the additional risks posed by rDNA-modified microorganisms are minor. Only long-term observations can, however, confirm this assumption, and consequently the highest feasible containment measures should still be used in the years to come.
Microbiology, 2005
... J Clin Pathol 29, 938940.[Abstract/Free Full Text]. Musa, MO, Al Douri, M., Khan, S., Shafi,... more ... J Clin Pathol 29, 938940.[Abstract/Free Full Text]. Musa, MO, Al Douri, M., Khan, S., Shafi, T., Al Humaidh, A. & Al Rasheed, AM (1998). ... Toh, M., Moffitt, MC, Henrichsen, L., Raftery, M., Barrow, K., Cox, JM, Marquis, CP & Neilan, BA (2004). ...
Microbiology, 1999
Detailed functional analysis revealed the modular organization of pGI2, a 9672 bp plasmid from Ba... more Detailed functional analysis revealed the modular organization of pGI2, a 9672 bp plasmid from Bacillus thuringiensis H1.q that harbours the 4149 bp transposon Tn4430. Whereas the pG12 leading-strand replicon was identified through deletion experiments, sequence comparisons indicated the presence of an sso,-like single-strand origin commonly found among Bacillus plasmids. Southern hybridizatkn confirmed the existence of ssDNA intermediates, but only in the case of plasmid derivatives lacking the ssot site. Moreover, the pG12 replication protein Rep displayed significant similarity with that of pTX14-3, a 7 6 kb plasmid from 6. thuringiensis serovar israelensis, suggesting that both elements are representatives of a new family of rolling-circle replicating (RCR) plasmids. In addition, both plasmids share a conserved 320 bp region downstream of their rep genes which, in the case of pG12, appeared indispensable for replication. This region is therefore likely to correspond to, or to be part of, the actual double-strand origin of both plasmids. Another interesting feature of pCl2 is the presence of a mobilization (Mob) protein, as demonstrated by its ability to be mobilized by the conjugative plasmid pAW63 from B. thuringiensis serovar kurstalci HD73. The same transfer system was also used to unambiguously demonstrate similar properties of the related Mob-like protein from pTX14-3. A closer analysis of this family of related Mob proteins suggested a subdomanial organization among its members. Finally, the 270 residue pGl2 ORF2 was shown to be related to ORF43 of pMRCO1, a 60 kb conjugative plasmid from Lactococcus lactis subsp. ladis. Although no function has been assigned to the putative ORF43 protein, it is located downstream of a bacteriocin operon, next to an 15946 element. pG12 appears thus far as an assemblage of functional modules with no obvious metabolic function, presumabty acting as a reservoir of carrier (rep and so), rearrangement (Tn4430) or recruiting (Mob) entities for its bacterial host.
Microbiology, 1999
Quantitative measurements of horizontal DNA transfer are critical if one wishes to address questi... more Quantitative measurements of horizontal DNA transfer are critical if one wishes to address questions relating to ecology, evolution and the safe use of recombinant bacteria. Traditionally, the efficiency of a conjugation system has been described by its transfer frequency. However, transfer frequencies can be determined in many ways and may be sensitive to physical, chemical and biological conditions. In this study the authors have used the mechanistic similarity between bacterial conjugation and simple enzyme catalysis in order to calculate the maximal conjugation rate (V max) and the recipient concentration (K m) at which the conjugation rate is half its maximal value, for two different conjugation systems : the F plasmid from Escherichia coli and plasmid pCF10 from Enterococcus faecalis. The results are compared with the data obtained from the aggregation-mediated conjugation system encoded on pXO16 from Bacillus thuringiensis. The conjugation systems analysed are fundamentally different ; however, they have some characteristics in common : they are able to sustain conjugative transfer in liquid medium and the transfer efficiencies are very high. Conjugation encoded by the F plasmid in E. coli involves the formation of small aggregates (2-20 cells), established by sex pili, and the plasmid's maximal conjugation rate was estimated to be approximately 015 transconjugants per donor per minute. Pheromone-induced conjugation in Ent. faecalis, which involves the formation of large aggregates, was found to proceed at a maximal conjugation rate of 029 transconjugants per donor per minute. Also, the K m value differed significantly between these conjugation systems ; this may reflect the inherent differences in mating pair formation and transfer mechanisms. In these conjugation systems, the donors underwent a ' recovery period ' between rounds of conjugative transfer and newly formed transconjugants required a period of about 40-80 min to mature into proficient donors.
Relation, 2008
Background: Comparative genomics is a powerful means of establishing inter-specific relationships... more Background: Comparative genomics is a powerful means of establishing inter-specific relationships between gene function/location and allows insight into genomic rearrangements, conservation and evolutionary phylogeny. The availability of the complete sequence of the chicken genome has initiated the development of detailed genomic information in other birds including turkey, an agriculturally important species where mapping has hitherto focused on linkage with limited physical information. No molecular study has yet examined conservation of avian microchromosomes, nor differences in copy number variants (CNVs) between birds. Results: We present a detailed comparative cytogenetic map between chicken and turkey based on reciprocal chromosome painting and mapping of 338 chicken BACs to turkey metaphases. Two inter-chromosomal changes (both involving centromeres) and three pericentric inversions have been identified between chicken and turkey; and array CGH identified 16 inter-specific CNVs. Conclusion: This is the first study to combine the modalities of zoo-FISH and array CGH between different avian species. The first insight into the conservation of microchromosomes, the first comparative cytogenetic map of any bird and the first appraisal of CNVs between birds is provided. Results suggest that avian genomes have remained relatively stable during evolution compared to mammalian equivalents.
International Journal of Food Microbiology, 2005
Based on a combination of PCR and restriction endonuclease (RE) digestion (PCR-RE digestion), we ... more Based on a combination of PCR and restriction endonuclease (RE) digestion (PCR-RE digestion), we have examined the possibility of differentiating members of the Bacillus cereus group. Fragments of the gyrB gene (362 bp) from pure cultures of 12 B. cereus, 25 B. thuringiensis, 25 B. mycoides and two B. anthracis strains were amplified and subsequently digested with Sau3A1. Furthermore, a majority of the amplicons were sequenced directly to verify the PCR-RE results. The results obtained suggest that only the B. mycoides generates specific fragments following PCR-RE. Conversely, it was not possible to discriminate between the B. cereus and the B. thuringiensis strains using the methods described.