Jozef Anne | KU Leuven (original) (raw)
Papers by Jozef Anne
Asian Pacific Journal of Tropical Disease, 2015
Fems Immunology and Medical Microbiology, 2001
Applied Microbiology and Biotechnology, 2012
Streptomyces lividans has shown potential as an expression system for heterologous proteins. Over... more Streptomyces lividans has shown potential as an expression system for heterologous proteins. Overexpression of proteic factors important for heterologous protein production is a valuable approach to improve yields of such proteins. Comparative transcriptomic analysis revealed that several genes were differentially expressed in strains involved in heterologous protein production. For instance, the gene-encoding phosphoenolpyruvate carboxykinase (pepck) showed a significant twofold change in recombinant S. lividans producing human tumour necrosis factor-alpha (hTNF-α). The effect of pepck overexpression on S. lividans TK24 and its hTNF-α producing recombinant was thus investigated in bench-top fermenters. Results obtained revealed that pepck overexpression resulted into a twofold increase in specific PEPCK activity during growth. This overexpression is correlated with slower growth rate, reduced excretion of pyruvate and less alkalinisation of the growth medium when compared with the control strain. After 26 h of fermentation, hTNF-α yields were enhanced (up to 1.7-fold) in the pepck-overexpressing S. lividans TK24, demonstrating that this metabolic engineering approach is indeed promising for heterologous protein production.
Journal of Biotechnology, 2006
MGG Molecular & General Genetics, 1996
The impact of the codon bias of the mouse tumour necrosis factor alpha (mTNF) gene cloned in Stre... more The impact of the codon bias of the mouse tumour necrosis factor alpha (mTNF) gene cloned in Streptomyces lividans on the efficiency of expression and secretion was analysed. Minor codons occurring in the mTNF gene were therefore adapted to the codon bias of Streptomyces by site-directed mutagenesis. No improvement in mTNF yield could be detected. The stability of the transcript derived from the construct was shown to be more important for determining the final level of mTNF production. A strong correlation was observed between the yield of secreted biologically active mTNF and the amount of mTNF mRNA present in the cells.
Applied Microbiology and Biotechnology, 1990
Archives of Microbiology, 2004
Legionella pneumophila is commonly found in freshwater environments and is able to invade and rep... more Legionella pneumophila is commonly found in freshwater environments and is able to invade and replicate within amoebae and ciliated protozoa. Moreover, this bacterium is also able to replicate within human alveolar macrophages causing a severe form of pneumonia, designated Legionnaires' disease. L. pneumophila pathogenesis is not yet completely understood, but the genes responsible for infection and intracellular replication are becoming known. Nonetheless, knowledge as to how these genes are controlled is still very limited. The partially sequenced genome of L. pneumophila was searched for open reading frames encoding proteins with sequence similarity to members of the LuxR family of transcriptional regulators. These were designated LpnR1, LpnR2, LpnR3, and LpnR4. Although these proteins could not be identified as true LuxR proteins, they do act as regulators, as illustrated in this report. LpnR1 negatively affected rpoS expression, whereas LpnR2 and LpnR3 positively affected flagellin expression. Furthermore, LpnR2 proved to be necessary for efficient invasion of Acanthamoeba castellanii and LpnR3 for intracellular replication in this protozoan host. LpnR4 was recently identified as LetA.
Journal of Business …, 2005
An efficient synthesis of a library of 5-amino-thiazolo[4,5-d]pyrimidines is reported. Regioselec... more An efficient synthesis of a library of 5-amino-thiazolo[4,5-d]pyrimidines is reported. Regioselective displacements of chlorines, as well as regioselective diazotation reactions are described, which allow the introduction of structural diversity on the scaffold by consecutive reactions. Screening of this focused library led to the discovery of SecA inhibitors from Escherichia coli and Staphylococcus aureus.
Chemistry & Biodiversity, 2011
The 2-(1,2-dihydro-3-oxo-3H-pyrazol-2-yl)benzothiazole scaffold was selected as a central core st... more The 2-(1,2-dihydro-3-oxo-3H-pyrazol-2-yl)benzothiazole scaffold was selected as a central core structure for the discovery of novel antibacterial compounds. A systematic variation of the substituents on the oxo-pyrazole moiety, as well as on the benzo moiety, led to the creation of a small and focused library of benzothiazoles that was subjected to antibacterial screening. In a first round of screening, activity of the compounds against six representative microorganisms was established. For the most potent congeners, MIC values against S. aureus and P. aeruginosa were determined. The structure-activity relationship study clearly revealed that subtle structural variations influence the antibacterial activity to a large extent. The most potent congeners displayed MIC values of 3.30 μM.
Analytical Biochemistry
A major pathway for bacterial preprotein translocation is provided by the Sec-dependent preprotei... more A major pathway for bacterial preprotein translocation is provided by the Sec-dependent preprotein translocation pathway. Proteins destined for Sec-dependent translocation are synthesized as preproteins with an N-terminal signal peptide, which targets them to the SecYEG translocase channel. The driving force for the translocation reaction is provided by the peripheral membrane ATPase SecA, which couples the hydrolysis of ATP to the stepwise transport of unfolded preproteins across the bacterial membrane. Since SecA is essential, highly conserved among bacterial species, and has no close human homologues, it represents a promising target for antibacterial chemotherapy. However, high-throughput screening (HTS) campaigns to identify SecA inhibitors are hampered by the low intrinsic ATPase activity of SecA and the requirement of hydrophobic membranes for measuring the membrane or translocation ATPase activity of SecA. To address this issue, we have developed a colorimetric high-throughp...
The Journal of antibiotics, Jan 20, 2015
The rapid rise of antibiotic-resistant bacteria is one of the major concerns in modern medicine. ... more The rapid rise of antibiotic-resistant bacteria is one of the major concerns in modern medicine. Therefore, to treat bacterial infections, there is an urgent need for new antibacterials-preferably directed against alternative bacterial targets. One such potential target is the preprotein translocation motor SecA. SecA is a peripheral membrane ATPase and a key component of the Sec secretion pathway, the major route for bacterial protein export across or into the cytoplasmic membrane. As SecA is essential for bacterial viability, ubiquitous and highly conserved in bacteria, but not present in eukaryotic cells, it represents an attractive antibacterial target. Using an in silico approach, we have defined several potentially druggable and conserved pockets on the surface of SecA. We show that three of these potentially druggable sites are important for SecA function. A starting collection of ~500 000 commercially available small-molecules was virtually screened against a predicted drugg...
Bioorganic & Medicinal Chemistry, 2011
An efficient synthesis of a library of 5-amino-thiazolo[4,5-d]pyrimidines is reported. Regioselec... more An efficient synthesis of a library of 5-amino-thiazolo[4,5-d]pyrimidines is reported. Regioselective displacements of chlorines, as well as regioselective diazotation reactions are described, which allow the introduction of structural diversity on the scaffold by consecutive reactions. Screening of this focused library led to the discovery of SecA inhibitors from Escherichia coli and Staphylococcus aureus.
Journal of Microbiological Methods, 2013
Journal of Business …, 2005
Anticancer research
Attenuated Salmonella typhimurium has been demonstrated as a potential gene delivery vector. Prev... more Attenuated Salmonella typhimurium has been demonstrated as a potential gene delivery vector. Previous findings induce the necessity to optimize tumor selectivity and bacterial dosing in relation to tumor volume and intratumoral therapeutic gene expression. Attenuated Salmonella VNP20009 and VNP20047 (expressing cytosine deaminase) were systemically administered to tumor-bearing rats. The bacteria were quantified in tumor and normal organs. Conversion of 5-fluorocytosine to 5-fluorouracil was evaluated using thin layer chromatography. Tumor colonization efficiency was dependent on Salmonella density, administration route and tumor volume. Colonization of normal tissues gradually decreased with time, while intratumoral proliferation of bacteria remained high during the follow-up period. The Optimal Therapeutic Dose (OTD) was found to be 5.10(7) cfu/rat. Intratumoral VNP20047-expressed CDase leading to the conversion of 5-FC to 5-FU was detected in vivo. Our results indicate the need t...
Asian Pacific Journal of Tropical Disease, 2015
Fems Immunology and Medical Microbiology, 2001
Applied Microbiology and Biotechnology, 2012
Streptomyces lividans has shown potential as an expression system for heterologous proteins. Over... more Streptomyces lividans has shown potential as an expression system for heterologous proteins. Overexpression of proteic factors important for heterologous protein production is a valuable approach to improve yields of such proteins. Comparative transcriptomic analysis revealed that several genes were differentially expressed in strains involved in heterologous protein production. For instance, the gene-encoding phosphoenolpyruvate carboxykinase (pepck) showed a significant twofold change in recombinant S. lividans producing human tumour necrosis factor-alpha (hTNF-α). The effect of pepck overexpression on S. lividans TK24 and its hTNF-α producing recombinant was thus investigated in bench-top fermenters. Results obtained revealed that pepck overexpression resulted into a twofold increase in specific PEPCK activity during growth. This overexpression is correlated with slower growth rate, reduced excretion of pyruvate and less alkalinisation of the growth medium when compared with the control strain. After 26 h of fermentation, hTNF-α yields were enhanced (up to 1.7-fold) in the pepck-overexpressing S. lividans TK24, demonstrating that this metabolic engineering approach is indeed promising for heterologous protein production.
Journal of Biotechnology, 2006
MGG Molecular & General Genetics, 1996
The impact of the codon bias of the mouse tumour necrosis factor alpha (mTNF) gene cloned in Stre... more The impact of the codon bias of the mouse tumour necrosis factor alpha (mTNF) gene cloned in Streptomyces lividans on the efficiency of expression and secretion was analysed. Minor codons occurring in the mTNF gene were therefore adapted to the codon bias of Streptomyces by site-directed mutagenesis. No improvement in mTNF yield could be detected. The stability of the transcript derived from the construct was shown to be more important for determining the final level of mTNF production. A strong correlation was observed between the yield of secreted biologically active mTNF and the amount of mTNF mRNA present in the cells.
Applied Microbiology and Biotechnology, 1990
Archives of Microbiology, 2004
Legionella pneumophila is commonly found in freshwater environments and is able to invade and rep... more Legionella pneumophila is commonly found in freshwater environments and is able to invade and replicate within amoebae and ciliated protozoa. Moreover, this bacterium is also able to replicate within human alveolar macrophages causing a severe form of pneumonia, designated Legionnaires' disease. L. pneumophila pathogenesis is not yet completely understood, but the genes responsible for infection and intracellular replication are becoming known. Nonetheless, knowledge as to how these genes are controlled is still very limited. The partially sequenced genome of L. pneumophila was searched for open reading frames encoding proteins with sequence similarity to members of the LuxR family of transcriptional regulators. These were designated LpnR1, LpnR2, LpnR3, and LpnR4. Although these proteins could not be identified as true LuxR proteins, they do act as regulators, as illustrated in this report. LpnR1 negatively affected rpoS expression, whereas LpnR2 and LpnR3 positively affected flagellin expression. Furthermore, LpnR2 proved to be necessary for efficient invasion of Acanthamoeba castellanii and LpnR3 for intracellular replication in this protozoan host. LpnR4 was recently identified as LetA.
Journal of Business …, 2005
An efficient synthesis of a library of 5-amino-thiazolo[4,5-d]pyrimidines is reported. Regioselec... more An efficient synthesis of a library of 5-amino-thiazolo[4,5-d]pyrimidines is reported. Regioselective displacements of chlorines, as well as regioselective diazotation reactions are described, which allow the introduction of structural diversity on the scaffold by consecutive reactions. Screening of this focused library led to the discovery of SecA inhibitors from Escherichia coli and Staphylococcus aureus.
Chemistry & Biodiversity, 2011
The 2-(1,2-dihydro-3-oxo-3H-pyrazol-2-yl)benzothiazole scaffold was selected as a central core st... more The 2-(1,2-dihydro-3-oxo-3H-pyrazol-2-yl)benzothiazole scaffold was selected as a central core structure for the discovery of novel antibacterial compounds. A systematic variation of the substituents on the oxo-pyrazole moiety, as well as on the benzo moiety, led to the creation of a small and focused library of benzothiazoles that was subjected to antibacterial screening. In a first round of screening, activity of the compounds against six representative microorganisms was established. For the most potent congeners, MIC values against S. aureus and P. aeruginosa were determined. The structure-activity relationship study clearly revealed that subtle structural variations influence the antibacterial activity to a large extent. The most potent congeners displayed MIC values of 3.30 μM.
Analytical Biochemistry
A major pathway for bacterial preprotein translocation is provided by the Sec-dependent preprotei... more A major pathway for bacterial preprotein translocation is provided by the Sec-dependent preprotein translocation pathway. Proteins destined for Sec-dependent translocation are synthesized as preproteins with an N-terminal signal peptide, which targets them to the SecYEG translocase channel. The driving force for the translocation reaction is provided by the peripheral membrane ATPase SecA, which couples the hydrolysis of ATP to the stepwise transport of unfolded preproteins across the bacterial membrane. Since SecA is essential, highly conserved among bacterial species, and has no close human homologues, it represents a promising target for antibacterial chemotherapy. However, high-throughput screening (HTS) campaigns to identify SecA inhibitors are hampered by the low intrinsic ATPase activity of SecA and the requirement of hydrophobic membranes for measuring the membrane or translocation ATPase activity of SecA. To address this issue, we have developed a colorimetric high-throughp...
The Journal of antibiotics, Jan 20, 2015
The rapid rise of antibiotic-resistant bacteria is one of the major concerns in modern medicine. ... more The rapid rise of antibiotic-resistant bacteria is one of the major concerns in modern medicine. Therefore, to treat bacterial infections, there is an urgent need for new antibacterials-preferably directed against alternative bacterial targets. One such potential target is the preprotein translocation motor SecA. SecA is a peripheral membrane ATPase and a key component of the Sec secretion pathway, the major route for bacterial protein export across or into the cytoplasmic membrane. As SecA is essential for bacterial viability, ubiquitous and highly conserved in bacteria, but not present in eukaryotic cells, it represents an attractive antibacterial target. Using an in silico approach, we have defined several potentially druggable and conserved pockets on the surface of SecA. We show that three of these potentially druggable sites are important for SecA function. A starting collection of ~500 000 commercially available small-molecules was virtually screened against a predicted drugg...
Bioorganic & Medicinal Chemistry, 2011
An efficient synthesis of a library of 5-amino-thiazolo[4,5-d]pyrimidines is reported. Regioselec... more An efficient synthesis of a library of 5-amino-thiazolo[4,5-d]pyrimidines is reported. Regioselective displacements of chlorines, as well as regioselective diazotation reactions are described, which allow the introduction of structural diversity on the scaffold by consecutive reactions. Screening of this focused library led to the discovery of SecA inhibitors from Escherichia coli and Staphylococcus aureus.
Journal of Microbiological Methods, 2013
Journal of Business …, 2005
Anticancer research
Attenuated Salmonella typhimurium has been demonstrated as a potential gene delivery vector. Prev... more Attenuated Salmonella typhimurium has been demonstrated as a potential gene delivery vector. Previous findings induce the necessity to optimize tumor selectivity and bacterial dosing in relation to tumor volume and intratumoral therapeutic gene expression. Attenuated Salmonella VNP20009 and VNP20047 (expressing cytosine deaminase) were systemically administered to tumor-bearing rats. The bacteria were quantified in tumor and normal organs. Conversion of 5-fluorocytosine to 5-fluorouracil was evaluated using thin layer chromatography. Tumor colonization efficiency was dependent on Salmonella density, administration route and tumor volume. Colonization of normal tissues gradually decreased with time, while intratumoral proliferation of bacteria remained high during the follow-up period. The Optimal Therapeutic Dose (OTD) was found to be 5.10(7) cfu/rat. Intratumoral VNP20047-expressed CDase leading to the conversion of 5-FC to 5-FU was detected in vivo. Our results indicate the need t...