Anne Scheie - Academia.edu (original) (raw)

Papers by Anne Scheie

Den norske tannlegeforenings Tidende

PLOS ONE, 2016

Interference with bacterial quorum sensing communication provides an anti-virulence strategy to c... more Interference with bacterial quorum sensing communication provides an anti-virulence strategy to control pathogenic bacteria. Here, using the Enteropathogenic E. coli (EPEC) O103: H2, we showed for the first time that thiophenone TF101 reduced expression of lsrB; the gene encoding the AI-2 receptor. Combined results of transcriptional and phenotypic analyses suggested that TF101 interfere with AI-2 signalling, possibly by competing with AI-2 for binding to LsrB. This is supported by in silico docking prediction of thiophenone TF101 in the LsrB pocket. Transcriptional analyses furthermore showed that thiophenone TF101 interfered with expression of the virulence genes eae and fimH. In addition, TF101 reduced AI-2 induced E. coli adhesion to colorectal adenocarcinoma cells. TF101, on the other hand, did not affect epinephrine or norepinephrine enhanced E. coli adhesion. Overall, our results showed that thiophenone TF101 interfered with virulence expression in E. coli O103:H2, suggestedly by interfering with AI-2 mediated quorum sensing. We thus conclude that thiophenone TF101 might represent a promising future anti-virulence agent in the fight against pathogenic E. coli.

Aquaculture, 2013

Vibriosis outbreaks caused by Vibrio harveyi and related species are amongst the major obstacles ... more Vibriosis outbreaks caused by Vibrio harveyi and related species are amongst the major obstacles for the further expansion of giant freshwater prawn (Macrobrachium rosenbergii) larviculture. Vibrio harveyi regulates virulence gene expression through quorum sensing, bacterial cell-to-cell communication, and consequently, quorum sensing disruption has been suggested as an alternative strategy to control infections caused by these bacteria. Previous studies have shown that quorum sensing-disrupting compounds are able to disrupt quorum sensing in Vibrio harveyi. In this study, we demonstrated that the quorum sensing-disrupting compounds cinnamaldehyde, (Z-)-4-bromo-5-(bromomethylene)-2(5H)-furanone and (Z)-4-((5-(bromomethylene)-2oxo-2,5-dihydrothiophen-3-yl)metoxy)-4-oxobutanoic acid increased the survival of giant freshwater prawn larvae when challenged to pathogenic Vibrio harveyi. Our in vivo challenge test showed that cinnamaldehyde and the thiophenone can protect the larvae from Vibrio harveyi infection when dosed to the culture water at 1 μM and 10 μM, whereas the brominated furanone offered protection at 1 μM but resulted in complete mortality at 10 μM. Although there were significant differences in survival between challenged larvae with and without addition of quorum sensing-disrupting compounds, there were no differences in growth (as determined by the larval stage index).

PubMed, Apr 1, 1996

The aim of this study was to investigate the efficacy of a pre-brushing rinse containing sodium b... more The aim of this study was to investigate the efficacy of a pre-brushing rinse containing sodium benzoate and alcohol, on 2 week old dental plaque. In a double-blind, placebo-controlled crossover study 20 individuals abstained from oral hygiene for periods of 2 weeks. Ten individuals were then assigned to rinse once for 30 seconds with either the test mouthrinse or a placebo mouthrinse. Following this, all individuals had their teeth cleaned and maintained proper oral hygiene for four weeks before the experiment was repeated. This time, the control individuals were assigned to the test rinse and vice versa. Using the Plaque Index on three buccal sites on all teeth, plaque was recorded before and after rinsing, as well as following a subsequent toothbrushing. For metabolic studies plaque from the lingual surfaces on the teeth in one quadrant in the upper and the lower jaw was sampled before rinsing and from the two remaining quadrants following the rinse, and analysed. There was no difference in Plaque Index between the two experimental periods. An oral rinse with the test mouthrinse had no effect on the amount of plaque, nor did it enhance the subsequent plaque removal after brushing. The independent biochemical analysis showed a significant effect of rinsing on the glycolytic potential, but with no effect on the glycolytic profile, which was similar for test and control plaque samples. Thus, a single oral rinse with a mouthrinse containing sodium benzoate and alcohol does not affect removal of plaque nor does it seems to influence the glycolytic potential of the plaque.

PLOS ONE, Jun 16, 2016

Interference with bacterial quorum sensing communication provides an anti-virulence strategy to c... more Interference with bacterial quorum sensing communication provides an anti-virulence strategy to control pathogenic bacteria. Here, using the Enteropathogenic E. coli (EPEC) O103: H2, we showed for the first time that thiophenone TF101 reduced expression of lsrB; the gene encoding the AI-2 receptor. Combined results of transcriptional and phenotypic analyses suggested that TF101 interfere with AI-2 signalling, possibly by competing with AI-2 for binding to LsrB. This is supported by in silico docking prediction of thiophenone TF101 in the LsrB pocket. Transcriptional analyses furthermore showed that thiophenone TF101 interfered with expression of the virulence genes eae and fimH. In addition, TF101 reduced AI-2 induced E. coli adhesion to colorectal adenocarcinoma cells. TF101, on the other hand, did not affect epinephrine or norepinephrine enhanced E. coli adhesion. Overall, our results showed that thiophenone TF101 interfered with virulence expression in E. coli O103:H2, suggestedly by interfering with AI-2 mediated quorum sensing. We thus conclude that thiophenone TF101 might represent a promising future anti-virulence agent in the fight against pathogenic E. coli.

ChemInform, May 2, 2013

Reaction of (Z)-5-(Bromomethylene)thiophen-2(5H)-one with Some Nucleophiles in Search for New Bio... more Reaction of (Z)-5-(Bromomethylene)thiophen-2(5H)-one with Some Nucleophiles in Search for New Biofilm Inhibitors.-The nucleophilic substitution of the bromo substituent in title compound (I) is studied. The reaction fails with ammonium acetate or potassium cyanate and leads in fact to dimeric and trimeric ring opening products like (XI) and (XII). Actually, this reaction represents a stereospecific access to penta-2,4-dienoates. Selected substitution products are tested for their biofilm inhibition activity. Slight activity is observed only for aromatic sulfur compounds, e.g. (IIId).-(BENNECHE*, T.; CHAMGORDANI, E.

Caries Research, 1994

Mouthrinses containing zinc ions inhibit plaque acidogenicity, but the effect is transient. Zinc-... more Mouthrinses containing zinc ions inhibit plaque acidogenicity, but the effect is transient. Zinc-containing apatite or zinc phosphate precipitated within dental plaque might serve as a reservoir for zinc ions, thus providing prolonged inhibition of acid formation. Zinc-containing fluorhydroxyapatite was prepared from solutions containing CaCl2, KH2PO4, NaF and increasing amounts of ZnCl2 (0.0, 0.005, 0.02, 0.1, 0.2 or 1 mM; minerals No. 1-6, respectively) by raising the pH with ammonia. Zinc phosphate tetrahydrate (mineral No. 7) was prepared in a similar manner from a solution containing ZnCl2 and KH2PO4 only. Dense cell suspensions of Streptococcus mutans NCTC 10449 were incubated with 14C-glucose and one of the test minerals (No. 1-7). Glycolysis was allowed to proceed, with or without pH control, in a pH-stat. Samples were withdrawn at 1, 2, and 3 min, and extracellular glycolytic metabolites were identified by HPLC. Mineral No. 7 inhibited glycolysis and any pH fall almost completely. With the pH fixed at 5.5, reduction of glucose consumption and lactate formation was 83 and 93%, respectively, compared to the no-zinc control mineral (No. 1). No changes in glucose consumption or lactate formation were evident in the presence of minerals No. 2-6. All apatitic minerals had a buffering effect and, in the absence of pH control, glycolysis was increased due to the higher pH. Detectable levels of fluoride were not released by any mineral into the incubation mixture, and zinc only by minerals No. 6 and 7 in greater than trace amounts.(ABSTRACT TRUNCATED AT 250 WORDS)

Journal of Applied Microbiology, Jul 19, 2016

The present aims were firstly to coat metal implant material with a quorum sensing inhibitory thi... more The present aims were firstly to coat metal implant material with a quorum sensing inhibitory thiophenone molecule, and secondly to assess the inhibitory effect on Staphylococcus epidermidis biofilm accumulation on thiophenone‐coated coupons.

Den norske tannlegeforenings Tidende, Sep 13, 2018

Oral Microbiology and Immunology, Mar 19, 2002

Long-term xylitol consumption leads to the emergence of xylitol-resistant (X-R) mutans streptococ... more Long-term xylitol consumption leads to the emergence of xylitol-resistant (X-R) mutans streptococci. The aim of the present study was to compare cariogenic traits in X-R and xylitol-sensitive (X-S) strains. Six strains of mutans streptococci, three X-R and three X-S strains, were studied. Xylitol resistance and sensitivity were confirmed by growth in xylitol-supplemented media. Acid production from glucose or fructose or uptake of xylitol was initiated by adding 14 C-labelled glucose, fructose or xylitol to bacterial suspensions. The resultant metabolites were identified by HPLC. Lactate was the major metabolite from glucose, whether the bacteria were grown in the presence or the absence of xylitol.

Persons working for VKM, either as appointed members of the Committee or as ad hoc experts, do th... more Persons working for VKM, either as appointed members of the Committee or as ad hoc experts, do this by virtue of their scientific expertise, not as representatives of their employers. The Civil Services Act instructions on legal competence apply to all work prepared by VKM.

Den norske tannlegeforenings Tidende

Artikkelen er en sterkt utvidet og popularisert versjon av et debattinnlegg («Letter to the Edito... more Artikkelen er en sterkt utvidet og popularisert versjon av et debattinnlegg («Letter to the Editor») i Journal of Periodontology 2014; 85: 374-84. Comments to systematic reviews on the combination of metronidazole and amoxicillin. J Periodontology' har gitt tillatelse til å trykke denne norske versjonen i NTFs Tidende.

Persons working for VKM, either as appointed members of the Committee or as ad hoc experts, do th... more Persons working for VKM, either as appointed members of the Committee or as ad hoc experts, do this by virtue of their scientific expertise, not as representatives of their employers. The Civil Services Act instructions on legal competence apply to all work prepared by VKM.

The objective of the present toxicological evaluation is, as stated in the terms of reference, to... more The objective of the present toxicological evaluation is, as stated in the terms of reference, to review and update the toxicological information and assess the margin of safety in the use of triclosan (cas no. 3380-34-5) in cosmetics. There is an extensive database on the toxicology of triclosan, which covers acute-, subchronicand chronic toxicity, carcinogenicity, reproductiveand developmental toxicity, genotoxicity, irritation/sensitisation studies, toxicokinetic data as well as studies in humans (1-4). Triclosan is approved for use in cosmetic products in the European Union. However, we have not been able to find any toxicological evaluation (by e.g. SCCNFP) underlying this approval. Triclosan is approved in EU for use in food contact material made of plastic and in that context in 2000 the EU Scientific Committee on Food (SCF) did a toxicological evaluation of triclosan (5). The safety of triclosan in cosmetic products has been evaluated by the cosmetic industry (1-4). Particul...

Letters in Organic Chemistry, 2016

Chemosphere, 2016

Thiophenones are novel quorum sensing inhibitors that can control biofilm formation. QSAR predict... more Thiophenones are novel quorum sensing inhibitors that can control biofilm formation. QSAR predictions significantly under estimated the environmental fate and effects. Confirmatory ecotoxicity tests are necessary when risk assessing novel compounds.

Aktuel Nordisk Odontologi, 2016

Caries Research, 1988

A double-blind crossover study on 4 adult volunteers was performed to evaluate the effect of hexe... more A double-blind crossover study on 4 adult volunteers was performed to evaluate the effect of hexetidine on Cu2+ accumulation in dental plaque as well as a possible enhanced effect of copper on inhibition of acid production in the presence of hexetidine. The experimental period was 5 days. No oral hygiene was allowed, and sucrose-containing chewing gum was used to enhance plaque formation during the test period. In order to evaluate the effect on pH, the test persons rinsed with a 15% glucose (w/v) solution on the 5th experimental day. Plaque pH values recorded before and 5 min after the rinse served as control values. One hour later the test persons rinsed with 10 ml of the test solutions for 1 min. Glucose rinses with pH measurements 5 min after the rinse were carried out 0, 3, and 7 h after the test agents were used. The combination of 1.0 mM copper and 2.0 mM hexetidine gave a significant (p less than 0.05) inhibition of acid production at all times compared both to the controls and to each of the test agents separately. Plaque samples were collected with a toothpick immediately before a 1-min rinse with 10 ml of the test solutions. Subsequent plaque samples were taken 5 min and 3 and 8 h after a rinse from corresponding tooth surfaces. Dry weight was estimated, the plaque bacteria digested by HNO3, and the amount of Cu2+ determined by atomic absorption.(ABSTRACT TRUNCATED AT 250 WORDS)

Oral Microbiology and Immunology, Dec 19, 2007

Autoinducer-2 (AI-2) is used by several bacteria in quorum-sensing signaling and is a product of ... more Autoinducer-2 (AI-2) is used by several bacteria in quorum-sensing signaling and is a product of LuxS. The aim was to investigate the effect of LuxS mutation on expression of Streptococcus intermedius virulence factors. S. intermedius mutants were constructed by insertion inactivation or gene deletion. Real time RT-PCR was used to assess transcription of pas, ily and hyl. Hyaluronidase and intermedilysin activities were measured biochemically. The results indicated that disruption of luxS in S. intermedius may affect hyaluronidase and intermedilysin gene expressions. No difference in antigen I/II expression was observed. Biochemical methods showed a five-fold decrease in hemolytic activity of the luxS mutant; however, secreted hyaluronidase activity was unaffected. The AI-2 precursor 4,5-dihydroxy-2,3-pentanedione complemented lack of AI-2 production by the mutant thus restoring hemolytic activity. We suggest that AI-2 communication is involved in intermedilysin expression.

Aktuel nordisk odontologi, Jan 23, 2017

Den norske tannlegeforenings Tidende

PLOS ONE, 2016

Interference with bacterial quorum sensing communication provides an anti-virulence strategy to c... more Interference with bacterial quorum sensing communication provides an anti-virulence strategy to control pathogenic bacteria. Here, using the Enteropathogenic E. coli (EPEC) O103: H2, we showed for the first time that thiophenone TF101 reduced expression of lsrB; the gene encoding the AI-2 receptor. Combined results of transcriptional and phenotypic analyses suggested that TF101 interfere with AI-2 signalling, possibly by competing with AI-2 for binding to LsrB. This is supported by in silico docking prediction of thiophenone TF101 in the LsrB pocket. Transcriptional analyses furthermore showed that thiophenone TF101 interfered with expression of the virulence genes eae and fimH. In addition, TF101 reduced AI-2 induced E. coli adhesion to colorectal adenocarcinoma cells. TF101, on the other hand, did not affect epinephrine or norepinephrine enhanced E. coli adhesion. Overall, our results showed that thiophenone TF101 interfered with virulence expression in E. coli O103:H2, suggestedly by interfering with AI-2 mediated quorum sensing. We thus conclude that thiophenone TF101 might represent a promising future anti-virulence agent in the fight against pathogenic E. coli.

Aquaculture, 2013

Vibriosis outbreaks caused by Vibrio harveyi and related species are amongst the major obstacles ... more Vibriosis outbreaks caused by Vibrio harveyi and related species are amongst the major obstacles for the further expansion of giant freshwater prawn (Macrobrachium rosenbergii) larviculture. Vibrio harveyi regulates virulence gene expression through quorum sensing, bacterial cell-to-cell communication, and consequently, quorum sensing disruption has been suggested as an alternative strategy to control infections caused by these bacteria. Previous studies have shown that quorum sensing-disrupting compounds are able to disrupt quorum sensing in Vibrio harveyi. In this study, we demonstrated that the quorum sensing-disrupting compounds cinnamaldehyde, (Z-)-4-bromo-5-(bromomethylene)-2(5H)-furanone and (Z)-4-((5-(bromomethylene)-2oxo-2,5-dihydrothiophen-3-yl)metoxy)-4-oxobutanoic acid increased the survival of giant freshwater prawn larvae when challenged to pathogenic Vibrio harveyi. Our in vivo challenge test showed that cinnamaldehyde and the thiophenone can protect the larvae from Vibrio harveyi infection when dosed to the culture water at 1 μM and 10 μM, whereas the brominated furanone offered protection at 1 μM but resulted in complete mortality at 10 μM. Although there were significant differences in survival between challenged larvae with and without addition of quorum sensing-disrupting compounds, there were no differences in growth (as determined by the larval stage index).

PubMed, Apr 1, 1996

The aim of this study was to investigate the efficacy of a pre-brushing rinse containing sodium b... more The aim of this study was to investigate the efficacy of a pre-brushing rinse containing sodium benzoate and alcohol, on 2 week old dental plaque. In a double-blind, placebo-controlled crossover study 20 individuals abstained from oral hygiene for periods of 2 weeks. Ten individuals were then assigned to rinse once for 30 seconds with either the test mouthrinse or a placebo mouthrinse. Following this, all individuals had their teeth cleaned and maintained proper oral hygiene for four weeks before the experiment was repeated. This time, the control individuals were assigned to the test rinse and vice versa. Using the Plaque Index on three buccal sites on all teeth, plaque was recorded before and after rinsing, as well as following a subsequent toothbrushing. For metabolic studies plaque from the lingual surfaces on the teeth in one quadrant in the upper and the lower jaw was sampled before rinsing and from the two remaining quadrants following the rinse, and analysed. There was no difference in Plaque Index between the two experimental periods. An oral rinse with the test mouthrinse had no effect on the amount of plaque, nor did it enhance the subsequent plaque removal after brushing. The independent biochemical analysis showed a significant effect of rinsing on the glycolytic potential, but with no effect on the glycolytic profile, which was similar for test and control plaque samples. Thus, a single oral rinse with a mouthrinse containing sodium benzoate and alcohol does not affect removal of plaque nor does it seems to influence the glycolytic potential of the plaque.

PLOS ONE, Jun 16, 2016

Interference with bacterial quorum sensing communication provides an anti-virulence strategy to c... more Interference with bacterial quorum sensing communication provides an anti-virulence strategy to control pathogenic bacteria. Here, using the Enteropathogenic E. coli (EPEC) O103: H2, we showed for the first time that thiophenone TF101 reduced expression of lsrB; the gene encoding the AI-2 receptor. Combined results of transcriptional and phenotypic analyses suggested that TF101 interfere with AI-2 signalling, possibly by competing with AI-2 for binding to LsrB. This is supported by in silico docking prediction of thiophenone TF101 in the LsrB pocket. Transcriptional analyses furthermore showed that thiophenone TF101 interfered with expression of the virulence genes eae and fimH. In addition, TF101 reduced AI-2 induced E. coli adhesion to colorectal adenocarcinoma cells. TF101, on the other hand, did not affect epinephrine or norepinephrine enhanced E. coli adhesion. Overall, our results showed that thiophenone TF101 interfered with virulence expression in E. coli O103:H2, suggestedly by interfering with AI-2 mediated quorum sensing. We thus conclude that thiophenone TF101 might represent a promising future anti-virulence agent in the fight against pathogenic E. coli.

ChemInform, May 2, 2013

Reaction of (Z)-5-(Bromomethylene)thiophen-2(5H)-one with Some Nucleophiles in Search for New Bio... more Reaction of (Z)-5-(Bromomethylene)thiophen-2(5H)-one with Some Nucleophiles in Search for New Biofilm Inhibitors.-The nucleophilic substitution of the bromo substituent in title compound (I) is studied. The reaction fails with ammonium acetate or potassium cyanate and leads in fact to dimeric and trimeric ring opening products like (XI) and (XII). Actually, this reaction represents a stereospecific access to penta-2,4-dienoates. Selected substitution products are tested for their biofilm inhibition activity. Slight activity is observed only for aromatic sulfur compounds, e.g. (IIId).-(BENNECHE*, T.; CHAMGORDANI, E.

Caries Research, 1994

Mouthrinses containing zinc ions inhibit plaque acidogenicity, but the effect is transient. Zinc-... more Mouthrinses containing zinc ions inhibit plaque acidogenicity, but the effect is transient. Zinc-containing apatite or zinc phosphate precipitated within dental plaque might serve as a reservoir for zinc ions, thus providing prolonged inhibition of acid formation. Zinc-containing fluorhydroxyapatite was prepared from solutions containing CaCl2, KH2PO4, NaF and increasing amounts of ZnCl2 (0.0, 0.005, 0.02, 0.1, 0.2 or 1 mM; minerals No. 1-6, respectively) by raising the pH with ammonia. Zinc phosphate tetrahydrate (mineral No. 7) was prepared in a similar manner from a solution containing ZnCl2 and KH2PO4 only. Dense cell suspensions of Streptococcus mutans NCTC 10449 were incubated with 14C-glucose and one of the test minerals (No. 1-7). Glycolysis was allowed to proceed, with or without pH control, in a pH-stat. Samples were withdrawn at 1, 2, and 3 min, and extracellular glycolytic metabolites were identified by HPLC. Mineral No. 7 inhibited glycolysis and any pH fall almost completely. With the pH fixed at 5.5, reduction of glucose consumption and lactate formation was 83 and 93%, respectively, compared to the no-zinc control mineral (No. 1). No changes in glucose consumption or lactate formation were evident in the presence of minerals No. 2-6. All apatitic minerals had a buffering effect and, in the absence of pH control, glycolysis was increased due to the higher pH. Detectable levels of fluoride were not released by any mineral into the incubation mixture, and zinc only by minerals No. 6 and 7 in greater than trace amounts.(ABSTRACT TRUNCATED AT 250 WORDS)

Journal of Applied Microbiology, Jul 19, 2016

The present aims were firstly to coat metal implant material with a quorum sensing inhibitory thi... more The present aims were firstly to coat metal implant material with a quorum sensing inhibitory thiophenone molecule, and secondly to assess the inhibitory effect on Staphylococcus epidermidis biofilm accumulation on thiophenone‐coated coupons.

Den norske tannlegeforenings Tidende, Sep 13, 2018

Oral Microbiology and Immunology, Mar 19, 2002

Long-term xylitol consumption leads to the emergence of xylitol-resistant (X-R) mutans streptococ... more Long-term xylitol consumption leads to the emergence of xylitol-resistant (X-R) mutans streptococci. The aim of the present study was to compare cariogenic traits in X-R and xylitol-sensitive (X-S) strains. Six strains of mutans streptococci, three X-R and three X-S strains, were studied. Xylitol resistance and sensitivity were confirmed by growth in xylitol-supplemented media. Acid production from glucose or fructose or uptake of xylitol was initiated by adding 14 C-labelled glucose, fructose or xylitol to bacterial suspensions. The resultant metabolites were identified by HPLC. Lactate was the major metabolite from glucose, whether the bacteria were grown in the presence or the absence of xylitol.

Persons working for VKM, either as appointed members of the Committee or as ad hoc experts, do th... more Persons working for VKM, either as appointed members of the Committee or as ad hoc experts, do this by virtue of their scientific expertise, not as representatives of their employers. The Civil Services Act instructions on legal competence apply to all work prepared by VKM.

Den norske tannlegeforenings Tidende

Artikkelen er en sterkt utvidet og popularisert versjon av et debattinnlegg («Letter to the Edito... more Artikkelen er en sterkt utvidet og popularisert versjon av et debattinnlegg («Letter to the Editor») i Journal of Periodontology 2014; 85: 374-84. Comments to systematic reviews on the combination of metronidazole and amoxicillin. J Periodontology' har gitt tillatelse til å trykke denne norske versjonen i NTFs Tidende.

Persons working for VKM, either as appointed members of the Committee or as ad hoc experts, do th... more Persons working for VKM, either as appointed members of the Committee or as ad hoc experts, do this by virtue of their scientific expertise, not as representatives of their employers. The Civil Services Act instructions on legal competence apply to all work prepared by VKM.

The objective of the present toxicological evaluation is, as stated in the terms of reference, to... more The objective of the present toxicological evaluation is, as stated in the terms of reference, to review and update the toxicological information and assess the margin of safety in the use of triclosan (cas no. 3380-34-5) in cosmetics. There is an extensive database on the toxicology of triclosan, which covers acute-, subchronicand chronic toxicity, carcinogenicity, reproductiveand developmental toxicity, genotoxicity, irritation/sensitisation studies, toxicokinetic data as well as studies in humans (1-4). Triclosan is approved for use in cosmetic products in the European Union. However, we have not been able to find any toxicological evaluation (by e.g. SCCNFP) underlying this approval. Triclosan is approved in EU for use in food contact material made of plastic and in that context in 2000 the EU Scientific Committee on Food (SCF) did a toxicological evaluation of triclosan (5). The safety of triclosan in cosmetic products has been evaluated by the cosmetic industry (1-4). Particul...

Letters in Organic Chemistry, 2016

Chemosphere, 2016

Thiophenones are novel quorum sensing inhibitors that can control biofilm formation. QSAR predict... more Thiophenones are novel quorum sensing inhibitors that can control biofilm formation. QSAR predictions significantly under estimated the environmental fate and effects. Confirmatory ecotoxicity tests are necessary when risk assessing novel compounds.

Aktuel Nordisk Odontologi, 2016

Caries Research, 1988

A double-blind crossover study on 4 adult volunteers was performed to evaluate the effect of hexe... more A double-blind crossover study on 4 adult volunteers was performed to evaluate the effect of hexetidine on Cu2+ accumulation in dental plaque as well as a possible enhanced effect of copper on inhibition of acid production in the presence of hexetidine. The experimental period was 5 days. No oral hygiene was allowed, and sucrose-containing chewing gum was used to enhance plaque formation during the test period. In order to evaluate the effect on pH, the test persons rinsed with a 15% glucose (w/v) solution on the 5th experimental day. Plaque pH values recorded before and 5 min after the rinse served as control values. One hour later the test persons rinsed with 10 ml of the test solutions for 1 min. Glucose rinses with pH measurements 5 min after the rinse were carried out 0, 3, and 7 h after the test agents were used. The combination of 1.0 mM copper and 2.0 mM hexetidine gave a significant (p less than 0.05) inhibition of acid production at all times compared both to the controls and to each of the test agents separately. Plaque samples were collected with a toothpick immediately before a 1-min rinse with 10 ml of the test solutions. Subsequent plaque samples were taken 5 min and 3 and 8 h after a rinse from corresponding tooth surfaces. Dry weight was estimated, the plaque bacteria digested by HNO3, and the amount of Cu2+ determined by atomic absorption.(ABSTRACT TRUNCATED AT 250 WORDS)

Oral Microbiology and Immunology, Dec 19, 2007

Autoinducer-2 (AI-2) is used by several bacteria in quorum-sensing signaling and is a product of ... more Autoinducer-2 (AI-2) is used by several bacteria in quorum-sensing signaling and is a product of LuxS. The aim was to investigate the effect of LuxS mutation on expression of Streptococcus intermedius virulence factors. S. intermedius mutants were constructed by insertion inactivation or gene deletion. Real time RT-PCR was used to assess transcription of pas, ily and hyl. Hyaluronidase and intermedilysin activities were measured biochemically. The results indicated that disruption of luxS in S. intermedius may affect hyaluronidase and intermedilysin gene expressions. No difference in antigen I/II expression was observed. Biochemical methods showed a five-fold decrease in hemolytic activity of the luxS mutant; however, secreted hyaluronidase activity was unaffected. The AI-2 precursor 4,5-dihydroxy-2,3-pentanedione complemented lack of AI-2 production by the mutant thus restoring hemolytic activity. We suggest that AI-2 communication is involved in intermedilysin expression.

Aktuel nordisk odontologi, Jan 23, 2017