Monika Adamczyk-Popławska - Academia.edu (original) (raw)

Papers by Monika Adamczyk-Popławska

Research paper thumbnail of Ultrasensitive SERS platform made via femtosecond laser micromachining for biomedical applications

Journal of Materials Research and Technology

Research paper thumbnail of Haemophilus influenzae HP1 Bacteriophage Encodes a Lytic Cassette with a Pinholin and a Signal-Arrest-Release Endolysin

International Journal of Molecular Sciences

HP1 is a temperate bacteriophage, belonging to the Myoviridae family and infecting Haemophilus in... more HP1 is a temperate bacteriophage, belonging to the Myoviridae family and infecting Haemophilus influenzae Rd. By in silico analysis and molecular cloning, we characterized lys and hol gene products, present in the previously proposed lytic module of HP1 phage. The amino acid sequence of the lys gene product revealed the presence of signal-arrest-release (SAR) and muraminidase domains, characteristic for some endolysins. HP1 endolysin was able to induce lysis on its own when cloned and expressed in Escherichia coli, but the new phage release from infected H. influenzae cells was suppressed by inhibition of the secretion (sec) pathway. Protein encoded by hol gene is a transmembrane protein, with unusual C-out and N-in topology, when overexpressed/activated. Its overexpression in E. coli did not allow the formation of large pores (lack of leakage of β-galactosidase), but caused cell death (decrease in viable cell count) without lysis (turbidity remained constant). These data suggest th...

Research paper thumbnail of Inactivation of Genes Encoding MutL and MutS Proteins Influences Adhesion and Biofilm Formation by Neisseria gonorrhoeae

Microorganisms

Neisseria gonorrhoeae is an etiological agent of gonorrhea, which remains a global health problem... more Neisseria gonorrhoeae is an etiological agent of gonorrhea, which remains a global health problem. This bacterium possesses MutL and MutS DNA repair proteins encoded by mutL and mutS genes, whose inactivation causes a mutator phenotype. We have demonstrated the differential gene expression in N. gonorrhoeae mutL and mutS mutants using DNA microarrays. A subset of differentially expressed genes encodes proteins that can influence adhesion and biofilm formation. Compared to the wild-type strain, N. gonorrhoeae mutL and mutS mutants formed denser biofilms with increased biofilm-associated biomass on the abiotic surface. The N. gonorrhoeae mutS::km, but not the mutL mutant, was also more adherent and invasive to human epithelial cells. Further, during infection of epithelial cells with N. gonorrhoeae mutS::km, the expression of some bacterial genes encoding proteins that can influence gonococcal adhesion was changed compared with their expression in cells infected with the wild-type gon...

Research paper thumbnail of Activity of Vsr endonucleases encoded by Neisseria gonorrhoeae FA1090 is influenced by MutL and MutS proteins

BMC Microbiology

Background: The functioning of DNA repair systems is based on correct interactions between protei... more Background: The functioning of DNA repair systems is based on correct interactions between proteins involved in DNA repair. Very Short Patch (VSP) repair is a DNA repair system that corrects mismatches resulting from the deamination of 5-methylcytosine. The key enzyme in the VSP system is Vsr endonuclease, which can cleave mismatched DNA independently of accessory proteins. Until now, in vivo activity has only been shown for V.EcoKDcm-the only Vsr endonuclease in Escherichia coli. Additionally, the VSP system of E. coli is the only one for which interactions between proteins of the system have been demonstrated. Neisseria gonorrhoeae FA1090 is the first bacterium that we previously demonstrated to encode two active in vitro Vsr endonucleases: V.NgoAXIII and V.NgoAXIV. Results: We elucidate the mutator phenotype of N. gonorrhoeae mutants with disrupted genes encoding V.NgoAXIII or V.NgoAXIV endonuclease. Furthermore, we investigate the interactions between gonococcal Vsr endonucleases and MutL and MutS proteins. The Vsr endonucleases physically interact with gonococcal MutL protein but not with MutS protein. In the presence of the MutL protein, the efficiency of DNA cleavage by both V.NgoAXIII and V.NgoAXIV endonucleases increases, resulting in a decrease in the amount of Vsr enzyme required to complete digestion of mismatched DNA. Both Vsr endonucleases are also stimulated in vitro by the MutL protein of E. coli. In turn, the gonococcal MutS protein hinders DNA cleavage by the Vsr endonucleases. However, this effect is overridden in the presence of MutL, and furthermore, the simultaneous presence of MutL and MutS causes an increase in the efficiency of DNA cleavage by the Vsr endonucleases compared to the reaction catalyzed by V.NgoAXIII or V.NgoAXIV alone. Conclusions: For the first time, interactions between proteins of the DNA repair system encoded by N. gonorrhoeae that are responsible for the correction of mismatches resulting from the 5-methylcytosine deamination were identified. The increase in activity of Vsr endonucleases in the presence of MutL protein could allow for reduced synthesis of the Vsr endonucleases in cells, and the susceptibility of gonococcal Vsr endonucleases on MutL protein of E. coli implies a universal mechanism of Vsr stimulation by MutL protein.

Research paper thumbnail of Characterization of Vsr endonucleases from Neisseria meningitidis

Microbiology

DNA methylation is a common modification occurring in all living organisms. 5-methylcytosine, whi... more DNA methylation is a common modification occurring in all living organisms. 5-methylcytosine, which is produced in a reaction catalysed by C 5-methyltransferases, can spontaneously undergo deamination to thymine, leading to the formation of T:G mismatches and CfiT transitions. In Escherichia coli K-12, such mismatches are corrected by the Very Short Patch (VSP) repair system, with Vsr endonuclease as the key enzyme. Neisseria meningitidis possesses genes that encode DNA methyltransferases, including C 5-methyltransferases. We report on the mutagenic potential of the meningococcal C 5methyltransferases M.NmeDI and M.NmeAI resulting from deamination of 5-methylcytosine. N. meningitidis strains also possess genes encoding potential Vsr endonucleases. Phylogenetic analysis of meningococcal Vsr endonucleases indicates that they belong to two phylogenetically distinct groups (type I or type II Vsr endonucleases). N. meningitidis serogroup C (FAM18) is a representative of meningococcal strains that carry two Vsr endonuclease genes (V.Nme18IIP and V.Nme18VIP). The V.Nme18VIP (type II) endonuclease cut DNA containing T:G mismatches in all tested nucleotide contexts. V.Nme18IIP (type I) is not active in vitro, but the change of Tyr69 to His69 in the amino acid sequence of the protein restores its endonucleolytic activity. The presence of tyrosine in position 69 is a characteristic feature of type I meningococcal Vsr proteins, while type II Vsr endonucleases possess His69. In addition to the T:G mismatches, V.Nme18VIP and V.Nme18IIPY69H recognize and digest DNA with T:T or U:G mispairs. Thus, for the first time, we demonstrate that the VSP repair system may have a wider significance and broader substrate specificity than DNA lesions that only result from 5methylcytosine deamination.

Research paper thumbnail of Type III Methyltransferase M.NgoAX from Neisseria gonorrhoeae FA1090 Regulates Biofilm Formation and Interactions with Human Cells

Frontiers in Microbiology, 2015

Research paper thumbnail of Analysis of the filamentous bacteriophage genomes integrated into Neisseria gonorrhoeae FA1090 chromosome

Polish journal of microbiology / Polskie Towarzystwo Mikrobiologów = The Polish Society of Microbiologists, 2006

Bioinformatic analysis of the genome sequence of Neisseria gonorrhoeae revealed presence of four ... more Bioinformatic analysis of the genome sequence of Neisseria gonorrhoeae revealed presence of four specific prophage islands. Based on the similarity with other DNA phage sequences they seem to belong to the filamentous ssDNA phages group. Phages belonging to this group are also present in the genome of Neisseria meningitidis. The nucleotide and amino acids sequence of Ngo phi6 and Ngo phi7 show similar genetic organization and high homology on DNA and amino acid level. The Ngo phi9 contains only part of the genomes of the Ngo phi6-8 prophages. Several functionally same genes of different origin are duplicated, with no homology to their counterparts in phages Ngo phi6, Ngo phi7 and Ngo phi9. The prophage sequences of nucleotides of Ngo phi6 and Ngo phi7 contain specific blocks of genes responsible for phage DNA replication and structural proteins. Comparative analysis at nucleotide and amino acid level suggests that these sequences can encode functionally active phages. The genetic or...

Research paper thumbnail of 7beta-hydroxycholesterol blocked at C-3-OH inhibits growth of rat glioblastoma in vivo: comparison between 7beta-hydroxycholesteryl-3beta (ester)-oleate and 7beta-hydroxycholesteryl-3-beta-O (ether)-oleyl

Anticancer research

It was previously demonstrated that the 7beta-hydroxycholesteryl-3beta(ester)-oleate (7beta-ester... more It was previously demonstrated that the 7beta-hydroxycholesteryl-3beta(ester)-oleate (7beta-ester) possesses antitumor properties against the experimental rat C6 glioblastoma. The effect of an analog of this molecule, 7beta-hydroxycholesterol-3beta-O(ether)-oleyl (7beta-ether), was investigated. Liposomes containing no oxysterol (control), 7beta-ether or 7beta-ester were injected into tumors induced by C6 cells in rat brain cortex. At defined times, the animals were sacrificed, the tumors stained with cresyl violet and their volumes measured by densitometry. Oxysterol clearance was assessed by quantification from lipid extraction of treated tumors. The clearance of the new compound was slower than that of the 7beta-ester form. The 7beta-ether and 7beta-ester forms displayed similar antitumor activities against 3-day-old tumors. In contrast, the 7beta-ether form was more active on well-developed glioblastoma: 75 nmol inhibited tumor growth by 70% compared to controls, while the 7beta...

Research paper thumbnail of Glycophorin A in two patients with congenital dyserythropoietic anemia type I and type II is partly unglycosylated

Acta biochimica Polonica, 2000

Glycophorins A from erythrocyte membranes of two patients with congenital dyserythropoietic anemi... more Glycophorins A from erythrocyte membranes of two patients with congenital dyserythropoietic anemia type I and type II (CDA type I and II) were analyzed for carbohydrate molar composition employing a modification of the recently published method that allowed simultaneous determination of carbohydrates and protein in electrophoretic bands of glycoproteins separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (Zdebska & Kościelak, 1999, Anal Biochem., 275, 171-179). The modification involved a preliminary extraction of erythrocyte membranes with aqueous phenol, subsequent electrophoresis and analysis of the extracted glycophorins rather than electrophoresis and analysis of the glycophorin from intact erythrocyte membranes. The results showed a large deficit of N-acetylgalactosamine, galactose, and sialic acid residues in glycophorin A from patients with CDA type I and type II amounting to about 45% and 55%, respectively. The results strongly suggest that glycophorin A ...

Research paper thumbnail of The dam replacing gene product enhances Neisseria gonorrhoeae FA1090 viability and biofilm formation

Frontiers in microbiology, 2014

Many Neisseriaceae do not exhibit Dam methyltransferase activity and, instead of the dam gene, po... more Many Neisseriaceae do not exhibit Dam methyltransferase activity and, instead of the dam gene, possess drg (dam replacing gene) inserted in the leuS/dam locus. The drg locus in Neisseria gonorrhoeae FA1090 has a lower GC-pairs content (40.5%) compared to the whole genome of N. gonorrhoeae FA1090 (52%). The gonococcal drg gene encodes a DNA endonuclease Drg, with GmeATC specificity. Disruption of drg or insertion of the dam gene in gonococcal genome changes the level of expression of genes as shown by transcriptome analysis. For the drg-deficient N. gonorrhoeae mutant, a total of 195 (8.94% of the total gene pool) genes exhibited an altered expression compared to the wt strain by at least 1.5 fold. In dam-expressing N. gonorrhoeae mutant, the expression of 240 genes (11% of total genes) was deregulated. Most of these deregulated genes were involved in translation, DNA repair, membrane biogenesis and energy production as shown by cluster of orthologous group analysis. In vivo, the ina...

Research paper thumbnail of Local administration of 7β-hydroxycholesteryl-3-oleate inhibits growth of experimental rat C6 glioblastoma

Cancer research, 1994

The effect of 7jB-hydroxycholesteryl-3-oleate on rat brain C6 glioblastoma cells was studied. Thr... more The effect of 7jB-hydroxycholesteryl-3-oleate on rat brain C6 glioblastoma cells was studied. Three days after the inoculation of 2 • l0 s C6 cells into the frontal cortex of 6-day-old Wistar rats, two types of liposomes [consisting of either phosphatidylcholine and monosialoganglioside (PG:GM1, 10:1 moi/mol) only, or containing 7j3-hydroxycholesterol, 76hydroxycholesteryl-3-oleate, 7a-hydroxycholesteryl-3-oleate, or 7-ketocholesteryl-3-oleate] were injected into the xenograft. Ten days later, the animals were sacrificed, the tumors were stained with cresyl violet or hematoxylin/eosin, their volumes determined by image analysis, and their development followed by magnetic resonance imaging. The mean (_+ SE) tumor volume was 4.4 _+ 1.0 mm a. The injection of liposomes without oxysterol had no effect on tumor growth, whereas injection of liposomes containing 7g]-hydroxycholesteryl-3-oleate (36 nmol) gave rise to a marked decrease in tumor volume (from 4.4 _+ 1.0 to 0.7 + 0.4 mm3). Seven nmol had no effect on tumor growth, 72 nmol were as efficient as 36 nmol, and 144 nmol attenuated the tumor volume by 50% only. Liposomes containing 72 nmol of oleic acid enhanced the tumor volume 4-fold. These findings were confirmed by magnetic resonance imaging. Thus, following induction of tumors in both the right and left sides of the cortex and treatment of the right side, magnetic resonance imaging indicated a significant decrease in tumor volume on the right side only. When C6 cells and 7j~-hydroxycholeteryl-3-oleate were simultaneously injected, tumors did not develop in 80% of the animals. The clearance of [3H]7jB-hydroxycholesteryl-3-oleate, of which 75% was converted to cholesterol, reached 99% after 48 h. Other oxysterols did not affect the tumor volume except that 7-keto-cholesteryl-3-oleate decreased the tumor volume by 50%. Thus, the 3-fatty acyl ester and 7fl-hydroxyl groups are apparently required for the antitumor growth effect. Taken together, these data suggest that 7~-hydroxycholesteryl-3-oleate might be useful for local glioblastoma chemotherapy.

Research paper thumbnail of Tetra-amino-acid tandem repeats are involved in HsdS complementation in type IC restriction-modification systems

Microbiology, 2003

All known type I restriction and modification (R–M) systems of Escherichia coli and Salmonella en... more All known type I restriction and modification (R–M) systems of Escherichia coli and Salmonella enterica belong to one of four discrete families: type IA, IB, IC or ID. The classification of type I systems from a wide range of other genera is mainly based on complementation and molecular evidence derived from the comparison of the amino acid similarity of the corresponding subunits. This affiliation was seldom based on the strictest requirement for membership of a family, which depends on relatedness as demonstrated by complementation tests. This paper presents data indicating that the type I NgoAV R–M system from Neisseria gonorrhoeae, despite the very high identity of HsdM and HsdR subunits with members of the type IC family, does not show complementation with E. coli type IC R–M systems. Sequence analysis of the HsdS subunit of several different potential type IC R–M systems shows that the presence of different tetra-amino-acid sequence repeats, e.g. TAEL, LEAT, SEAL, TSEL, is cha...

Research paper thumbnail of Glycophorin A in two patients with congenital dyserythropoietic anemia type I and type II is partly unglycosylated

ACTA BIOCHIMICA …, 2000

anemia type I and II Glycophorins A from erythrocyte membranes of two patients with congenital dy... more anemia type I and II Glycophorins A from erythrocyte membranes of two patients with congenital dyserythropoietic anemia type I and type II (CDA type I and II) were analyzed for carbohydrate molar composition employing a modification of the recently published method that allowed simultaneous determination of carbohydrates and protein in electrophoretic bands of glycoproteins separated by sodium dodecyl sulfatepolyacrylamide gel electrophoresis (Zdebska & Kooecielak, 1999, Anal. Biochem., 275, 171-179). The modification involved a preliminary extraction of erythrocyte membranes with aqueous phenol, subsequent electrophoresis and analysis of the extracted glycophorins rather than electrophoresis and analysis of the glycophorin from intact erythrocyte membranes. The results showed a large deficit of N-acetylgalactosamine, galactose, and sialic acid residues in glycophorin A from patients with CDA type I and type II amounting to about 45% and 55 %, respectively. The results strongly suggest that glycophorin A in these patients is partly unglycosylated with respect to O-linked glycans. In addition, glycophorin A from erythrocytes of a patient with CDA II but not CDA I exhibited a significant deficit of mannose and N-acetylglucosamine suggesting that its N-glycosylation site was also partly unglycosylated. Congenital dyserythropoietic anemias (CDAs) are a group of rare hereditary diseases that are characterized by ineffective erythropoiesis and a certain degree of multinuclearity of erythroblasts (Wickramasinghe, 1998; 2000). Three principal types of the disease, differing in morphology and ultrastructure of erythroblasts as well as clinical symptoms, have been identified (Heimpel & Wendt, 1968). Erythrocytes from type II pa

Research paper thumbnail of Proteomics for development of vaccine

Journal of Proteomics, 2011

The success of genome projects has provided us with a vast amount of information on genes of many... more The success of genome projects has provided us with a vast amount of information on genes of many pathogenic species and has raised hopes for rapid progress in combating infectious diseases, both by construction of new effective vaccines and by creating a new generation of therapeutic drugs. Proteomics, a strategy complementary to the genomic-based approach, when combined with immunomics (looking for immunogenic proteins) and vaccinomics (characterization of host response to immunization), delivers valuable information on pathogen-host cell interaction. It also speeds the identification and detailed characterization of new antigens, which are potential candidates for vaccine development. This review begins with an overview of the global status of vaccinology based on WHO data. The main part of this review describes the impact of proteomic strategies on advancements in constructing effective antibacterial, antiviral and anticancer vaccines. Diverse aspects of disease mechanisms and disease preventions have been investigated by proteomics.

Research paper thumbnail of Inhibition of p42/p44 mitogen-activated protein kinase by oxysterols in rat astrocyte primary cultures and C6 glioma cell lines

Journal of Neuroscience Research, 1998

We previously demonstrated that oxysterols inhibit the growth of experimental glioblastoma induce... more We previously demonstrated that oxysterols inhibit the growth of experimental glioblastoma induced in the rat brain cortex. Mechanism of action of these compounds remains obscure. In this study, we investigated the effect of 7beta-hydroxycholesterol (7beta-OHCH) and 7ketocholesterol (7k-CH) on the growth and MAP kinase activity in three in vitro biological models: rat astrocyte primary cultures, primary cultures treated by dibutyryl-cAMP (reactive cells), and the C6 glioma cell line. The oxysterols are not lethal to primary astrocytes, even if MAP kinase activity is decreased, particularly when cells were treated with 7k-CH. Both oxysterols are toxic to reactive astrocytes, and as compared with untreated primary cultures, they amplified the MAP kinase activity decrease. However, the mechanism of action of oxysterols on reactive astrocytes seems not to be linked to the MAP kinase pathway. In highly proliferating C6 cell lines, only 7beta-OHCH has an antiproliferative effect and is cytotoxic. The inhibition of MAP kinase activity is a function of 7beta-OHCH concentration. PD098059, a MAP kinase pathway inhibitor, has only a time-limited antiproliferative effect on C6 cell growth. We conclude that in C6 cells, the MAP kinase activity decrease is correlated with the toxic effect of 7beta-OHCH and occurs at first stages of 7beta-OHCH action.

Research paper thumbnail of 7?-hydroxysterol is cytotoxic to neonatal rat astrocytes in primary culture when cAMP levels are increased

Journal of Neuroscience Research, 2000

ABSTRACT We have shown previously that 7beta-hydroxycholesterol (7betaOHCH) and 7beta-hydroxychol... more ABSTRACT We have shown previously that 7beta-hydroxycholesterol (7betaOHCH) and 7beta-hydroxycholesteryl-3-oleate (7betaOHCH- 3-OL) are potent inhibitors of lesion-induced astrogliosis in the rat cortex or spinal cord; these substances reduce reactive astrocyte proliferation and hypertrophy. In this study, we employed cultured newborn rat astrocytes with increased cAMP levels as an in vitro model of reactive astrocytes. Treatment with either dibutyryl-cAMP (dbcAMP) or isoproterenol resulted in morphologic differentiation of astrocytes which became fibrous. Concomitant incubation with 30 microM 7betaOHCH and dbcAMP (or isoproterenol) provoked the cells to retract and was cytotoxic. When the beta-adrenergic receptor-mediated cAMP increase was abolished by propranolol, the 7betaOHCH cytotoxicity was inhibited. Immunocytochemical labelling for glial fibrillary acidic protein (GFAP) and beta-tubulin and electron microscopy suggested that intermediate filament and microtubular organizations were modified by 7betaOHCH. Analysis of the activity of cAMP-dependent protein kinase (PKA) in astrocytes treated with dbcAMP and 7betaOHCH showed a rapid and marked inhibition of the phosphotransferase activity which lasted for 24 hr. We suggest that this culture system provides an experimental system to study the molecular mechanisms involved in the effect of oxysterols on astrocytic hypertrophy. The cytotoxicity of 7betaOHCH seems to be mediated by inhibition of PKA, which phosphorylates intermediate filaments and the transcription factor cyclic AMP responsive element binding.

Research paper thumbnail of Characterization of the NgoAXP: phase-variable type III restriction–modification system in Neisseria gonorrhoeae

FEMS Microbiology Letters, 2009

Methyltransferases associated with type III restriction-modification (RM) systems are phase-varia... more Methyltransferases associated with type III restriction-modification (RM) systems are phase-variably expressed in a variety of pathogenic bacteria. NgoAXP, the type III RM system encoded by Neisseria gonorrhoeae, was characterized in this study. The cloned resngoAXP and ngoAXPmod genes were expressed in Escherichia coli strains. The restriction and modification activities of NgoAXP were confirmed in vivo by the l phage restriction and modification test and in vitro by the methylation of DNA substrates in the presence of [methyl-3 H]AdoMet. As in all known type III systems, the restriction activity needed the presence of both genes, while the presence of the ngoAXPmod gene was sufficient for DNA methylation. Following its overexpression, the DNA methyltransferase M.NgoAXP was purified to apparent homogeneity using metal affinity chromatography. The specific sequence recognized by this enzyme was determined as a nonpalindromic sequence: 5 0-CCACC-3 0 , in which the adenine residue is methylated. We observed that in E. coli cells, the expression of the restriction phenotype associated with NgoAXP switched randomly. This phase variation was associated with the change in the number of pentanucleotide repeats (5 0-CCAAC/G-3 0) present at the 5 0-end of the coding region of the ngoAXPmod gene.

Research paper thumbnail of Proteomics for development of vaccine

Journal of …, 2011

The success of genome projects has provided us with a vast amount of information on genes of many... more The success of genome projects has provided us with a vast amount of information on genes of many pathogenic species and has raised hopes for rapid progress in combating infectious diseases, both by construction of new effective vaccines and by creating a new generation of therapeutic drugs. Proteomics, a strategy complementary to the genomic-based approach, when combined with immunomics (looking for immunogenic proteins) and vaccinomics (characterization of host response to immunization), delivers valuable information on pathogen-host cell interaction. It also speeds the identification and detailed characterization of new antigens, which are potential candidates for vaccine development. This review begins with an overview of the global status of vaccinology based on WHO data. The main part of this review describes the impact of proteomic strategies on advancements in constructing effective antibacterial, antiviral and anticancer vaccines. Diverse aspects of disease mechanisms and disease preventions have been investigated by proteomics.

Research paper thumbnail of Tetra-amino-acid tandem repeats are involved in HsdS complementation in type IC restriction–modification systems

…, 2003

All known type I restriction and modification (R–M) systems of Escherichia coli and Salmonella en... more All known type I restriction and modification (R–M) systems of Escherichia coli and Salmonella enterica belong to one of four discrete families: type IA, IB, IC or ID. The classification of type I systems from a wide range of other genera is mainly based on ...

Research paper thumbnail of Characterization of the dsDNA prophage sequences in the genome of Neisseria gonorrhoeae and visualization of productive bacteriophage

BMC Microbiology, 2007

Background: Bioinformatic analysis of the genome sequence of Neisseria gonorrhoeae revealed the p... more Background: Bioinformatic analysis of the genome sequence of Neisseria gonorrhoeae revealed the presence of nine probable prophage islands. The distribution, conservation and function of many of these sequences, and their ability to produce bacteriophage particles are unknown. Results: Our analysis of the genomic sequence of FA1090 identified five genomic regions (NgoΦ1-5) that are related to dsDNA lysogenic phage. The genetic content of the dsDNA prophage sequences were examined in detail and found to contain blocks of genes encoding for proteins homologous to proteins responsible for phage DNA replication, structural proteins and proteins responsible for phage assembly. The DNA sequences from NgoΦ1, NgoΦ2 and NgoΦ3 contain some significant regions of identity. A unique region of NgoΦ2 showed very high similarity with the Pseudomonas aeruginosa generalized transducing phage F116. Comparative analysis at the nucleotide and protein levels suggests that the sequences of NgoΦ1 and NgoΦ2 encode functionally active phages, while NgoΦ3, NgoΦ4 and NgoΦ5 encode incomplete genomes. Expression of the NgoΦ1 and NgoΦ2 repressors in Escherichia coli inhibit the growth of E. coli and the propagation of phage λ. The NgoΦ2 repressor was able to inhibit transcription of N. gonorrhoeae genes and Haemophilus influenzae HP1 phage promoters. The holin gene of NgoΦ1 (identical to that encoded by NgoΦ2), when expressed in E. coli, could serve as substitute for the phage λ s gene. We were able to detect the presence of the DNA derived from NgoΦ1 in the cultures of N. gonorrhoeae. Electron microscopy analysis of culture supernatants revealed the presence of multiple forms of bacteriophage particles. Conclusion: These data suggest that the genes similar to dsDNA lysogenic phage present in the gonococcus are generally conserved in this pathogen and that they are able to regulate the expression of other neisserial genes. Since phage particles were only present in culture supernatants after induction with mitomycin C, it indicates that the gonococcus also regulates the expression of bacteriophage genes.

Research paper thumbnail of Ultrasensitive SERS platform made via femtosecond laser micromachining for biomedical applications

Journal of Materials Research and Technology

Research paper thumbnail of Haemophilus influenzae HP1 Bacteriophage Encodes a Lytic Cassette with a Pinholin and a Signal-Arrest-Release Endolysin

International Journal of Molecular Sciences

HP1 is a temperate bacteriophage, belonging to the Myoviridae family and infecting Haemophilus in... more HP1 is a temperate bacteriophage, belonging to the Myoviridae family and infecting Haemophilus influenzae Rd. By in silico analysis and molecular cloning, we characterized lys and hol gene products, present in the previously proposed lytic module of HP1 phage. The amino acid sequence of the lys gene product revealed the presence of signal-arrest-release (SAR) and muraminidase domains, characteristic for some endolysins. HP1 endolysin was able to induce lysis on its own when cloned and expressed in Escherichia coli, but the new phage release from infected H. influenzae cells was suppressed by inhibition of the secretion (sec) pathway. Protein encoded by hol gene is a transmembrane protein, with unusual C-out and N-in topology, when overexpressed/activated. Its overexpression in E. coli did not allow the formation of large pores (lack of leakage of β-galactosidase), but caused cell death (decrease in viable cell count) without lysis (turbidity remained constant). These data suggest th...

Research paper thumbnail of Inactivation of Genes Encoding MutL and MutS Proteins Influences Adhesion and Biofilm Formation by Neisseria gonorrhoeae

Microorganisms

Neisseria gonorrhoeae is an etiological agent of gonorrhea, which remains a global health problem... more Neisseria gonorrhoeae is an etiological agent of gonorrhea, which remains a global health problem. This bacterium possesses MutL and MutS DNA repair proteins encoded by mutL and mutS genes, whose inactivation causes a mutator phenotype. We have demonstrated the differential gene expression in N. gonorrhoeae mutL and mutS mutants using DNA microarrays. A subset of differentially expressed genes encodes proteins that can influence adhesion and biofilm formation. Compared to the wild-type strain, N. gonorrhoeae mutL and mutS mutants formed denser biofilms with increased biofilm-associated biomass on the abiotic surface. The N. gonorrhoeae mutS::km, but not the mutL mutant, was also more adherent and invasive to human epithelial cells. Further, during infection of epithelial cells with N. gonorrhoeae mutS::km, the expression of some bacterial genes encoding proteins that can influence gonococcal adhesion was changed compared with their expression in cells infected with the wild-type gon...

Research paper thumbnail of Activity of Vsr endonucleases encoded by Neisseria gonorrhoeae FA1090 is influenced by MutL and MutS proteins

BMC Microbiology

Background: The functioning of DNA repair systems is based on correct interactions between protei... more Background: The functioning of DNA repair systems is based on correct interactions between proteins involved in DNA repair. Very Short Patch (VSP) repair is a DNA repair system that corrects mismatches resulting from the deamination of 5-methylcytosine. The key enzyme in the VSP system is Vsr endonuclease, which can cleave mismatched DNA independently of accessory proteins. Until now, in vivo activity has only been shown for V.EcoKDcm-the only Vsr endonuclease in Escherichia coli. Additionally, the VSP system of E. coli is the only one for which interactions between proteins of the system have been demonstrated. Neisseria gonorrhoeae FA1090 is the first bacterium that we previously demonstrated to encode two active in vitro Vsr endonucleases: V.NgoAXIII and V.NgoAXIV. Results: We elucidate the mutator phenotype of N. gonorrhoeae mutants with disrupted genes encoding V.NgoAXIII or V.NgoAXIV endonuclease. Furthermore, we investigate the interactions between gonococcal Vsr endonucleases and MutL and MutS proteins. The Vsr endonucleases physically interact with gonococcal MutL protein but not with MutS protein. In the presence of the MutL protein, the efficiency of DNA cleavage by both V.NgoAXIII and V.NgoAXIV endonucleases increases, resulting in a decrease in the amount of Vsr enzyme required to complete digestion of mismatched DNA. Both Vsr endonucleases are also stimulated in vitro by the MutL protein of E. coli. In turn, the gonococcal MutS protein hinders DNA cleavage by the Vsr endonucleases. However, this effect is overridden in the presence of MutL, and furthermore, the simultaneous presence of MutL and MutS causes an increase in the efficiency of DNA cleavage by the Vsr endonucleases compared to the reaction catalyzed by V.NgoAXIII or V.NgoAXIV alone. Conclusions: For the first time, interactions between proteins of the DNA repair system encoded by N. gonorrhoeae that are responsible for the correction of mismatches resulting from the 5-methylcytosine deamination were identified. The increase in activity of Vsr endonucleases in the presence of MutL protein could allow for reduced synthesis of the Vsr endonucleases in cells, and the susceptibility of gonococcal Vsr endonucleases on MutL protein of E. coli implies a universal mechanism of Vsr stimulation by MutL protein.

Research paper thumbnail of Characterization of Vsr endonucleases from Neisseria meningitidis

Microbiology

DNA methylation is a common modification occurring in all living organisms. 5-methylcytosine, whi... more DNA methylation is a common modification occurring in all living organisms. 5-methylcytosine, which is produced in a reaction catalysed by C 5-methyltransferases, can spontaneously undergo deamination to thymine, leading to the formation of T:G mismatches and CfiT transitions. In Escherichia coli K-12, such mismatches are corrected by the Very Short Patch (VSP) repair system, with Vsr endonuclease as the key enzyme. Neisseria meningitidis possesses genes that encode DNA methyltransferases, including C 5-methyltransferases. We report on the mutagenic potential of the meningococcal C 5methyltransferases M.NmeDI and M.NmeAI resulting from deamination of 5-methylcytosine. N. meningitidis strains also possess genes encoding potential Vsr endonucleases. Phylogenetic analysis of meningococcal Vsr endonucleases indicates that they belong to two phylogenetically distinct groups (type I or type II Vsr endonucleases). N. meningitidis serogroup C (FAM18) is a representative of meningococcal strains that carry two Vsr endonuclease genes (V.Nme18IIP and V.Nme18VIP). The V.Nme18VIP (type II) endonuclease cut DNA containing T:G mismatches in all tested nucleotide contexts. V.Nme18IIP (type I) is not active in vitro, but the change of Tyr69 to His69 in the amino acid sequence of the protein restores its endonucleolytic activity. The presence of tyrosine in position 69 is a characteristic feature of type I meningococcal Vsr proteins, while type II Vsr endonucleases possess His69. In addition to the T:G mismatches, V.Nme18VIP and V.Nme18IIPY69H recognize and digest DNA with T:T or U:G mispairs. Thus, for the first time, we demonstrate that the VSP repair system may have a wider significance and broader substrate specificity than DNA lesions that only result from 5methylcytosine deamination.

Research paper thumbnail of Type III Methyltransferase M.NgoAX from Neisseria gonorrhoeae FA1090 Regulates Biofilm Formation and Interactions with Human Cells

Frontiers in Microbiology, 2015

Research paper thumbnail of Analysis of the filamentous bacteriophage genomes integrated into Neisseria gonorrhoeae FA1090 chromosome

Polish journal of microbiology / Polskie Towarzystwo Mikrobiologów = The Polish Society of Microbiologists, 2006

Bioinformatic analysis of the genome sequence of Neisseria gonorrhoeae revealed presence of four ... more Bioinformatic analysis of the genome sequence of Neisseria gonorrhoeae revealed presence of four specific prophage islands. Based on the similarity with other DNA phage sequences they seem to belong to the filamentous ssDNA phages group. Phages belonging to this group are also present in the genome of Neisseria meningitidis. The nucleotide and amino acids sequence of Ngo phi6 and Ngo phi7 show similar genetic organization and high homology on DNA and amino acid level. The Ngo phi9 contains only part of the genomes of the Ngo phi6-8 prophages. Several functionally same genes of different origin are duplicated, with no homology to their counterparts in phages Ngo phi6, Ngo phi7 and Ngo phi9. The prophage sequences of nucleotides of Ngo phi6 and Ngo phi7 contain specific blocks of genes responsible for phage DNA replication and structural proteins. Comparative analysis at nucleotide and amino acid level suggests that these sequences can encode functionally active phages. The genetic or...

Research paper thumbnail of 7beta-hydroxycholesterol blocked at C-3-OH inhibits growth of rat glioblastoma in vivo: comparison between 7beta-hydroxycholesteryl-3beta (ester)-oleate and 7beta-hydroxycholesteryl-3-beta-O (ether)-oleyl

Anticancer research

It was previously demonstrated that the 7beta-hydroxycholesteryl-3beta(ester)-oleate (7beta-ester... more It was previously demonstrated that the 7beta-hydroxycholesteryl-3beta(ester)-oleate (7beta-ester) possesses antitumor properties against the experimental rat C6 glioblastoma. The effect of an analog of this molecule, 7beta-hydroxycholesterol-3beta-O(ether)-oleyl (7beta-ether), was investigated. Liposomes containing no oxysterol (control), 7beta-ether or 7beta-ester were injected into tumors induced by C6 cells in rat brain cortex. At defined times, the animals were sacrificed, the tumors stained with cresyl violet and their volumes measured by densitometry. Oxysterol clearance was assessed by quantification from lipid extraction of treated tumors. The clearance of the new compound was slower than that of the 7beta-ester form. The 7beta-ether and 7beta-ester forms displayed similar antitumor activities against 3-day-old tumors. In contrast, the 7beta-ether form was more active on well-developed glioblastoma: 75 nmol inhibited tumor growth by 70% compared to controls, while the 7beta...

Research paper thumbnail of Glycophorin A in two patients with congenital dyserythropoietic anemia type I and type II is partly unglycosylated

Acta biochimica Polonica, 2000

Glycophorins A from erythrocyte membranes of two patients with congenital dyserythropoietic anemi... more Glycophorins A from erythrocyte membranes of two patients with congenital dyserythropoietic anemia type I and type II (CDA type I and II) were analyzed for carbohydrate molar composition employing a modification of the recently published method that allowed simultaneous determination of carbohydrates and protein in electrophoretic bands of glycoproteins separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (Zdebska & Kościelak, 1999, Anal Biochem., 275, 171-179). The modification involved a preliminary extraction of erythrocyte membranes with aqueous phenol, subsequent electrophoresis and analysis of the extracted glycophorins rather than electrophoresis and analysis of the glycophorin from intact erythrocyte membranes. The results showed a large deficit of N-acetylgalactosamine, galactose, and sialic acid residues in glycophorin A from patients with CDA type I and type II amounting to about 45% and 55%, respectively. The results strongly suggest that glycophorin A ...

Research paper thumbnail of The dam replacing gene product enhances Neisseria gonorrhoeae FA1090 viability and biofilm formation

Frontiers in microbiology, 2014

Many Neisseriaceae do not exhibit Dam methyltransferase activity and, instead of the dam gene, po... more Many Neisseriaceae do not exhibit Dam methyltransferase activity and, instead of the dam gene, possess drg (dam replacing gene) inserted in the leuS/dam locus. The drg locus in Neisseria gonorrhoeae FA1090 has a lower GC-pairs content (40.5%) compared to the whole genome of N. gonorrhoeae FA1090 (52%). The gonococcal drg gene encodes a DNA endonuclease Drg, with GmeATC specificity. Disruption of drg or insertion of the dam gene in gonococcal genome changes the level of expression of genes as shown by transcriptome analysis. For the drg-deficient N. gonorrhoeae mutant, a total of 195 (8.94% of the total gene pool) genes exhibited an altered expression compared to the wt strain by at least 1.5 fold. In dam-expressing N. gonorrhoeae mutant, the expression of 240 genes (11% of total genes) was deregulated. Most of these deregulated genes were involved in translation, DNA repair, membrane biogenesis and energy production as shown by cluster of orthologous group analysis. In vivo, the ina...

Research paper thumbnail of Local administration of 7β-hydroxycholesteryl-3-oleate inhibits growth of experimental rat C6 glioblastoma

Cancer research, 1994

The effect of 7jB-hydroxycholesteryl-3-oleate on rat brain C6 glioblastoma cells was studied. Thr... more The effect of 7jB-hydroxycholesteryl-3-oleate on rat brain C6 glioblastoma cells was studied. Three days after the inoculation of 2 • l0 s C6 cells into the frontal cortex of 6-day-old Wistar rats, two types of liposomes [consisting of either phosphatidylcholine and monosialoganglioside (PG:GM1, 10:1 moi/mol) only, or containing 7j3-hydroxycholesterol, 76hydroxycholesteryl-3-oleate, 7a-hydroxycholesteryl-3-oleate, or 7-ketocholesteryl-3-oleate] were injected into the xenograft. Ten days later, the animals were sacrificed, the tumors were stained with cresyl violet or hematoxylin/eosin, their volumes determined by image analysis, and their development followed by magnetic resonance imaging. The mean (_+ SE) tumor volume was 4.4 _+ 1.0 mm a. The injection of liposomes without oxysterol had no effect on tumor growth, whereas injection of liposomes containing 7g]-hydroxycholesteryl-3-oleate (36 nmol) gave rise to a marked decrease in tumor volume (from 4.4 _+ 1.0 to 0.7 + 0.4 mm3). Seven nmol had no effect on tumor growth, 72 nmol were as efficient as 36 nmol, and 144 nmol attenuated the tumor volume by 50% only. Liposomes containing 72 nmol of oleic acid enhanced the tumor volume 4-fold. These findings were confirmed by magnetic resonance imaging. Thus, following induction of tumors in both the right and left sides of the cortex and treatment of the right side, magnetic resonance imaging indicated a significant decrease in tumor volume on the right side only. When C6 cells and 7j~-hydroxycholeteryl-3-oleate were simultaneously injected, tumors did not develop in 80% of the animals. The clearance of [3H]7jB-hydroxycholesteryl-3-oleate, of which 75% was converted to cholesterol, reached 99% after 48 h. Other oxysterols did not affect the tumor volume except that 7-keto-cholesteryl-3-oleate decreased the tumor volume by 50%. Thus, the 3-fatty acyl ester and 7fl-hydroxyl groups are apparently required for the antitumor growth effect. Taken together, these data suggest that 7~-hydroxycholesteryl-3-oleate might be useful for local glioblastoma chemotherapy.

Research paper thumbnail of Tetra-amino-acid tandem repeats are involved in HsdS complementation in type IC restriction-modification systems

Microbiology, 2003

All known type I restriction and modification (R–M) systems of Escherichia coli and Salmonella en... more All known type I restriction and modification (R–M) systems of Escherichia coli and Salmonella enterica belong to one of four discrete families: type IA, IB, IC or ID. The classification of type I systems from a wide range of other genera is mainly based on complementation and molecular evidence derived from the comparison of the amino acid similarity of the corresponding subunits. This affiliation was seldom based on the strictest requirement for membership of a family, which depends on relatedness as demonstrated by complementation tests. This paper presents data indicating that the type I NgoAV R–M system from Neisseria gonorrhoeae, despite the very high identity of HsdM and HsdR subunits with members of the type IC family, does not show complementation with E. coli type IC R–M systems. Sequence analysis of the HsdS subunit of several different potential type IC R–M systems shows that the presence of different tetra-amino-acid sequence repeats, e.g. TAEL, LEAT, SEAL, TSEL, is cha...

Research paper thumbnail of Glycophorin A in two patients with congenital dyserythropoietic anemia type I and type II is partly unglycosylated

ACTA BIOCHIMICA …, 2000

anemia type I and II Glycophorins A from erythrocyte membranes of two patients with congenital dy... more anemia type I and II Glycophorins A from erythrocyte membranes of two patients with congenital dyserythropoietic anemia type I and type II (CDA type I and II) were analyzed for carbohydrate molar composition employing a modification of the recently published method that allowed simultaneous determination of carbohydrates and protein in electrophoretic bands of glycoproteins separated by sodium dodecyl sulfatepolyacrylamide gel electrophoresis (Zdebska & Kooecielak, 1999, Anal. Biochem., 275, 171-179). The modification involved a preliminary extraction of erythrocyte membranes with aqueous phenol, subsequent electrophoresis and analysis of the extracted glycophorins rather than electrophoresis and analysis of the glycophorin from intact erythrocyte membranes. The results showed a large deficit of N-acetylgalactosamine, galactose, and sialic acid residues in glycophorin A from patients with CDA type I and type II amounting to about 45% and 55 %, respectively. The results strongly suggest that glycophorin A in these patients is partly unglycosylated with respect to O-linked glycans. In addition, glycophorin A from erythrocytes of a patient with CDA II but not CDA I exhibited a significant deficit of mannose and N-acetylglucosamine suggesting that its N-glycosylation site was also partly unglycosylated. Congenital dyserythropoietic anemias (CDAs) are a group of rare hereditary diseases that are characterized by ineffective erythropoiesis and a certain degree of multinuclearity of erythroblasts (Wickramasinghe, 1998; 2000). Three principal types of the disease, differing in morphology and ultrastructure of erythroblasts as well as clinical symptoms, have been identified (Heimpel & Wendt, 1968). Erythrocytes from type II pa

Research paper thumbnail of Proteomics for development of vaccine

Journal of Proteomics, 2011

The success of genome projects has provided us with a vast amount of information on genes of many... more The success of genome projects has provided us with a vast amount of information on genes of many pathogenic species and has raised hopes for rapid progress in combating infectious diseases, both by construction of new effective vaccines and by creating a new generation of therapeutic drugs. Proteomics, a strategy complementary to the genomic-based approach, when combined with immunomics (looking for immunogenic proteins) and vaccinomics (characterization of host response to immunization), delivers valuable information on pathogen-host cell interaction. It also speeds the identification and detailed characterization of new antigens, which are potential candidates for vaccine development. This review begins with an overview of the global status of vaccinology based on WHO data. The main part of this review describes the impact of proteomic strategies on advancements in constructing effective antibacterial, antiviral and anticancer vaccines. Diverse aspects of disease mechanisms and disease preventions have been investigated by proteomics.

Research paper thumbnail of Inhibition of p42/p44 mitogen-activated protein kinase by oxysterols in rat astrocyte primary cultures and C6 glioma cell lines

Journal of Neuroscience Research, 1998

We previously demonstrated that oxysterols inhibit the growth of experimental glioblastoma induce... more We previously demonstrated that oxysterols inhibit the growth of experimental glioblastoma induced in the rat brain cortex. Mechanism of action of these compounds remains obscure. In this study, we investigated the effect of 7beta-hydroxycholesterol (7beta-OHCH) and 7ketocholesterol (7k-CH) on the growth and MAP kinase activity in three in vitro biological models: rat astrocyte primary cultures, primary cultures treated by dibutyryl-cAMP (reactive cells), and the C6 glioma cell line. The oxysterols are not lethal to primary astrocytes, even if MAP kinase activity is decreased, particularly when cells were treated with 7k-CH. Both oxysterols are toxic to reactive astrocytes, and as compared with untreated primary cultures, they amplified the MAP kinase activity decrease. However, the mechanism of action of oxysterols on reactive astrocytes seems not to be linked to the MAP kinase pathway. In highly proliferating C6 cell lines, only 7beta-OHCH has an antiproliferative effect and is cytotoxic. The inhibition of MAP kinase activity is a function of 7beta-OHCH concentration. PD098059, a MAP kinase pathway inhibitor, has only a time-limited antiproliferative effect on C6 cell growth. We conclude that in C6 cells, the MAP kinase activity decrease is correlated with the toxic effect of 7beta-OHCH and occurs at first stages of 7beta-OHCH action.

Research paper thumbnail of 7?-hydroxysterol is cytotoxic to neonatal rat astrocytes in primary culture when cAMP levels are increased

Journal of Neuroscience Research, 2000

ABSTRACT We have shown previously that 7beta-hydroxycholesterol (7betaOHCH) and 7beta-hydroxychol... more ABSTRACT We have shown previously that 7beta-hydroxycholesterol (7betaOHCH) and 7beta-hydroxycholesteryl-3-oleate (7betaOHCH- 3-OL) are potent inhibitors of lesion-induced astrogliosis in the rat cortex or spinal cord; these substances reduce reactive astrocyte proliferation and hypertrophy. In this study, we employed cultured newborn rat astrocytes with increased cAMP levels as an in vitro model of reactive astrocytes. Treatment with either dibutyryl-cAMP (dbcAMP) or isoproterenol resulted in morphologic differentiation of astrocytes which became fibrous. Concomitant incubation with 30 microM 7betaOHCH and dbcAMP (or isoproterenol) provoked the cells to retract and was cytotoxic. When the beta-adrenergic receptor-mediated cAMP increase was abolished by propranolol, the 7betaOHCH cytotoxicity was inhibited. Immunocytochemical labelling for glial fibrillary acidic protein (GFAP) and beta-tubulin and electron microscopy suggested that intermediate filament and microtubular organizations were modified by 7betaOHCH. Analysis of the activity of cAMP-dependent protein kinase (PKA) in astrocytes treated with dbcAMP and 7betaOHCH showed a rapid and marked inhibition of the phosphotransferase activity which lasted for 24 hr. We suggest that this culture system provides an experimental system to study the molecular mechanisms involved in the effect of oxysterols on astrocytic hypertrophy. The cytotoxicity of 7betaOHCH seems to be mediated by inhibition of PKA, which phosphorylates intermediate filaments and the transcription factor cyclic AMP responsive element binding.

Research paper thumbnail of Characterization of the NgoAXP: phase-variable type III restriction–modification system in Neisseria gonorrhoeae

FEMS Microbiology Letters, 2009

Methyltransferases associated with type III restriction-modification (RM) systems are phase-varia... more Methyltransferases associated with type III restriction-modification (RM) systems are phase-variably expressed in a variety of pathogenic bacteria. NgoAXP, the type III RM system encoded by Neisseria gonorrhoeae, was characterized in this study. The cloned resngoAXP and ngoAXPmod genes were expressed in Escherichia coli strains. The restriction and modification activities of NgoAXP were confirmed in vivo by the l phage restriction and modification test and in vitro by the methylation of DNA substrates in the presence of [methyl-3 H]AdoMet. As in all known type III systems, the restriction activity needed the presence of both genes, while the presence of the ngoAXPmod gene was sufficient for DNA methylation. Following its overexpression, the DNA methyltransferase M.NgoAXP was purified to apparent homogeneity using metal affinity chromatography. The specific sequence recognized by this enzyme was determined as a nonpalindromic sequence: 5 0-CCACC-3 0 , in which the adenine residue is methylated. We observed that in E. coli cells, the expression of the restriction phenotype associated with NgoAXP switched randomly. This phase variation was associated with the change in the number of pentanucleotide repeats (5 0-CCAAC/G-3 0) present at the 5 0-end of the coding region of the ngoAXPmod gene.

Research paper thumbnail of Proteomics for development of vaccine

Journal of …, 2011

The success of genome projects has provided us with a vast amount of information on genes of many... more The success of genome projects has provided us with a vast amount of information on genes of many pathogenic species and has raised hopes for rapid progress in combating infectious diseases, both by construction of new effective vaccines and by creating a new generation of therapeutic drugs. Proteomics, a strategy complementary to the genomic-based approach, when combined with immunomics (looking for immunogenic proteins) and vaccinomics (characterization of host response to immunization), delivers valuable information on pathogen-host cell interaction. It also speeds the identification and detailed characterization of new antigens, which are potential candidates for vaccine development. This review begins with an overview of the global status of vaccinology based on WHO data. The main part of this review describes the impact of proteomic strategies on advancements in constructing effective antibacterial, antiviral and anticancer vaccines. Diverse aspects of disease mechanisms and disease preventions have been investigated by proteomics.

Research paper thumbnail of Tetra-amino-acid tandem repeats are involved in HsdS complementation in type IC restriction–modification systems

…, 2003

All known type I restriction and modification (R–M) systems of Escherichia coli and Salmonella en... more All known type I restriction and modification (R–M) systems of Escherichia coli and Salmonella enterica belong to one of four discrete families: type IA, IB, IC or ID. The classification of type I systems from a wide range of other genera is mainly based on ...

Research paper thumbnail of Characterization of the dsDNA prophage sequences in the genome of Neisseria gonorrhoeae and visualization of productive bacteriophage

BMC Microbiology, 2007

Background: Bioinformatic analysis of the genome sequence of Neisseria gonorrhoeae revealed the p... more Background: Bioinformatic analysis of the genome sequence of Neisseria gonorrhoeae revealed the presence of nine probable prophage islands. The distribution, conservation and function of many of these sequences, and their ability to produce bacteriophage particles are unknown. Results: Our analysis of the genomic sequence of FA1090 identified five genomic regions (NgoΦ1-5) that are related to dsDNA lysogenic phage. The genetic content of the dsDNA prophage sequences were examined in detail and found to contain blocks of genes encoding for proteins homologous to proteins responsible for phage DNA replication, structural proteins and proteins responsible for phage assembly. The DNA sequences from NgoΦ1, NgoΦ2 and NgoΦ3 contain some significant regions of identity. A unique region of NgoΦ2 showed very high similarity with the Pseudomonas aeruginosa generalized transducing phage F116. Comparative analysis at the nucleotide and protein levels suggests that the sequences of NgoΦ1 and NgoΦ2 encode functionally active phages, while NgoΦ3, NgoΦ4 and NgoΦ5 encode incomplete genomes. Expression of the NgoΦ1 and NgoΦ2 repressors in Escherichia coli inhibit the growth of E. coli and the propagation of phage λ. The NgoΦ2 repressor was able to inhibit transcription of N. gonorrhoeae genes and Haemophilus influenzae HP1 phage promoters. The holin gene of NgoΦ1 (identical to that encoded by NgoΦ2), when expressed in E. coli, could serve as substitute for the phage λ s gene. We were able to detect the presence of the DNA derived from NgoΦ1 in the cultures of N. gonorrhoeae. Electron microscopy analysis of culture supernatants revealed the presence of multiple forms of bacteriophage particles. Conclusion: These data suggest that the genes similar to dsDNA lysogenic phage present in the gonococcus are generally conserved in this pathogen and that they are able to regulate the expression of other neisserial genes. Since phage particles were only present in culture supernatants after induction with mitomycin C, it indicates that the gonococcus also regulates the expression of bacteriophage genes.