A Toll-like receptor recognizes bacterial DNA

DNA from bacteria has stimulatory effects on mammalian immune cells, which depend on the presence of unmethylated CpG dinucleotides in the bacterial DNA. In contrast, mammalian DNA has a low frequency of CpG dinucleotides, and these are mostly methylated; therefore, mammalian DNA does not have immuno-stimulatory activity. CpG DNA induces a strong T-helper-1-like inflammatory response. Accumulating evidence has revealed the therapeutic potential of CpG DNA as adjuvants for vaccination strategies for cancer, allergy and infectious diseases. Despite its promising clinical use, the molecular mechanism by which CpG DNA activates immune cells remains unclear. Here we show that cellular response to CpG DNA is mediated by a Toll-like receptor, TLR9. TLR9-deficient (TLR9-/-) mice did not show any response to CpG DNA, including proliferation of splenocytes, inflammatory cytokine production from macrophages and maturation of dendritic cells. TLR9-/- mice showed resistance to the lethal effect of CpG DNA without any elevation of serum pro-inflammatory cytokine levels. The in vivo CpG-DNA-mediated T-helper type-1 response was also abolished in TLR9-/- mice. Thus, vertebrate immune systems appear to have evolved a specific Toll-like receptor that distinguishes bacterial DNA from self-DNA.

Differential roles of TLR2 and TLR4 in recognition of gram-negative and gram-positive bacterial cell wall components

Toll-like receptor (TLR) 2 and TLR4 are implicated in the recognition of various bacterial cell wall components, such as lipopolysaccharide (LPS). To investigate in vivo roles of TLR2, we generated TLR2-deficient mice. In contrast to LPS unresponsiveness in TLR4-deficient mice, TLR2-deficient mice responded to LPS to the same extent as wild-type mice. TLR2-deficient macrophages were hyporesponsive to several Gram-positive bacterial cell walls as well as Staphylococcus aureus peptidoglycan. TLR4-deficient macrophages lacked the response to Gram-positive lipoteichoic acids. These results demonstrate that TLR2 and TLR4 recognize different bacterial cell wall components in vivo and TLR2 plays a major role in Gram-positive bacterial recognition.

Lipopolysaccharide stimulates the MyD88-independent pathway and results in activation of IFN-regulatory factor 3 and the expression of a subset of lipopolysaccharide-inducible genes

Bacterial lipopolysaccharide (LPS) triggers innate immune responses through Toll-like receptor (TLR) 4, a member of the TLR family that participates in pathogen recognition. TLRs recruit a cytoplasmic protein, MyD88, upon pathogen recognition, mediating its function for immune responses. Two major pathways for LPS have been suggested in recent studies, which are referred to as MyD88-dependent and -independent pathways. We report in this study the characterization of the MyD88-independent pathway via TLR4. MyD88-deficient cells failed to produce inflammatory cytokines in response to LPS, whereas they responded to LPS by activating IFN-regulatory factor 3 as well as inducing the genes containing IFN-stimulated regulatory elements such as IP-10. In contrast, a lipopeptide that activates TLR2 had no ability to activate IFN-regulatory factor 3. The MyD88-independent pathway was also activated in cells lacking both MyD88 and TNFR-associated factor 6. Thus, TLR4 signaling is composed of at least two distinct pathways, a MyD88-dependent pathway that is critical to the induction of inflammatory cytokines and a MyD88/TNFR-associated factor 6-independent pathway that regulates induction of IP-10.

Cutting edge: TLR2-deficient and MyD88-deficient mice are highly susceptible to Staphylococcus aureus infection

Toll-like receptor (TLR) family acts as pattern recognition receptors for pathogen-specific molecular patterns. We previously showed that TLR2 recognizes Gram-positive bacterial components whereas TLR4 recognizes LPS, a component of Gram-negative bacteria. MyD88 is shown to be an adaptor molecule essential for TLR family signaling. To investigate the role of TLR family in host defense against Gram-positive bacteria, we infected TLR2- and MyD88-deficient mice with Staphylococcus aureus. Both TLR2- and MyD88-deficient mice were highly susceptible to S. aureus infection, with more enhanced susceptibility in MyD88-deficient mice. Peritoneal macrophages from MyD88-deficient mice did not produce any detectable levels of cytokines in response to S. aureus. In contrast, TLR2-deficient macrophages produced reduced, but significant, levels of the cytokines, and TLR4-deficient macrophages produced the same amounts as wild-type cells, indicating that S. aureus is recognized not only by TLR2, but also by other TLR family members except for TLR4.

Identification and characterization of inhibitors of multidrug resistance efflux pumps in Pseudomonas aeruginosa: novel agents for combination therapy

Whole-cell assays were implemented to search for efflux pump inhibitors (EPIs) of the three multidrug resistance efflux pumps (MexAB-OprM, MexCD-OprJ, MexEF-OprN) that contribute to fluoroquinolone resistance in clinical isolates of Pseudomonas aeruginosa. Secondary assays were developed to identify lead compounds with exquisite activities as inhibitors. A broad-spectrum EPI which is active against all three known Mex efflux pumps from P. aeruginosa and their close Escherichia coli efflux pump homolog (AcrAB-TolC) was discovered. When this compound, MC-207,110, was used, the intrinsic resistance of P. aeruginosa to fluoroquinolones was decreased significantly (eightfold for levofloxacin). Acquired resistance due to the overexpression of efflux pumps was also decreased (32- to 64-fold reduction in the MIC of levofloxacin). Similarly, 32- to 64-fold reductions in MICs in the presence of MC-207,110 were observed for strains with overexpressed efflux pumps and various target mutations that confer resistance to levofloxacin (e.g., gyrA and parC). We also compared the frequencies of emergence of levofloxacin-resistant variants in the wild-type strain at four times the MIC of levofloxacin (1 microg/ml) when it was used either alone or in combination with EPI. In the case of levofloxacin alone, the frequency was approximately 10(-7) CFU/ml. In contrast, with an EPI, the frequency was below the level of detection (<10(-11)). In summary, we have demonstrated that inhibition of efflux pumps (i) decreased the level of intrinsic resistance significantly, (ii) reversed acquired resistance, and (iii) resulted in a decreased frequency of emergence of P. aeruginosa strains that are highly resistant to fluoroquinolones.

Cutting edge: preferentially the R-stereoisomer of the mycoplasmal lipopeptide macrophage-activating lipopeptide-2 activates immune cells through a toll-like receptor 2- and MyD88-dependent signaling pathway

Mycoplasmas and their membranes are potent activators of macrophages, the active principle being lipoproteins and lipopeptides. Two stereoisomers of the mycoplasmal lipopeptide macrophage-activating lipopeptide-2 (MALP-2) differing in the configuration of the lipid moiety were synthesized and compared in their macrophage-activating potential, the R-MALP being >100 times more active than the S-MALP in stimulating the release of cytokines, chemokines, and NO. To assess the role of the Toll-like receptor (TLR) family in mycoplasmal lipopeptide signaling, the MALP-2-mediated responses were analyzed using macrophages from wild-type, TLR2-, TLR4-, and MyD88-deficient mice. TLR2- and MyD88-deficient cells showed severely impaired cytokine productions in response to R- and S-MALP. The MALP-induced activation of intracellular signaling molecules was fully dependent on both TLR2 and MyD88. There was a strong preference for the R-MALP in the recognition by its functional receptor, TLR2.

Endotoxin-induced maturation of MyD88-deficient dendritic cells

LPS, a major component of the cell wall of Gram-negative bacteria, can induce a variety of biological responses including cytokine production from macrophages, B cell proliferation, and endotoxin shock. All of them were completely abolished in MyD88-deficient mice, indicating the essential role of MyD88 in LPS signaling. However, MyD88-deficient cells still show activation of NF-kappaB and mitogen-activated protein kinase cascades, although the biological significance of this activation is not clear. In this study, we have examined the effects of LPS on dendritic cells (DCs) from wild-type and several mutant mice. LPS-induced cytokine production from DCs was dependent on MyD88. However, LPS could induce functional maturation of MyD88-deficient DCs, including up-regulation of costimulatory molecules and enhancement of APC activity. MyD88-deficient DCs could not mature in response to bacterial DNA, the ligand for Toll-like receptor (TLR)9, indicating that MyD88 is differentially required for TLR family signaling. MyD88-dependent and -independent pathways originate at the intracytoplasmic region of TLR4, because both cytokine induction and functional maturation were abolished in DCs from C3H/HeJ mice carrying the point mutation in the region. Finally, in vivo analysis revealed that MyD88-, but not TLR4-, deficient splenic CD11c(+) DCs could up-regulate their costimulatory molecule expression in response to LPS. Collectively, the present study provides the first evidence that the MyD88-independent pathway downstream of TLR4 can lead to functional DC maturation, which is critical for a link between innate and adaptive immunity.

Immune cell activation by bacterial CpG-DNA through myeloid differentiation marker 88 and tumor necrosis factor receptor-associated factor (TRAF)6

Transition of immature antigen presenting cells (APCs) to the state of professional APCs is essential for initiation of cell-mediated immune responses to pathogens. Signal transduction via molecules of the Toll-like receptor (TLR)/interleukin 1 receptor (IL-1R) pathway is critical for activation of APCs either by pathogen-derived pattern ligands like lipopolysaccharides (LPS) or by CD40 ligation through T helper cells. The capacity of bacterial DNA (CpG-DNA) to induce APCs to differentiate into professional APCs represents an interesting discovery. However, the signaling pathways involved are poorly understood. Here we show that CpG-DNA activates the TLR/IL-1R signaling pathway via the molecules myeloid differentiation marker 88 (MyD88) and tumor necrosis factor receptor-associated factor 6 (TRAF6), leading to activation of kinases of the IkappaB kinase complex and the c-jun NH(2)-terminal kinases. Moreover, cells of TLR2- and TLR4-deficient mice are activated by CpG-DNA, whereas cells of MyD88-deficient mice do not respond. The data suggest that CpG-DNA initiates signaling via the TLR/IL-1R pathway in APCs in a manner similar to LPS and to T helper cell-mediated CD40 ligation. Activation of the TLR/IL-1R signaling pathway by foreign bacterial DNA may be one way to initiate innate defense mechanisms against infectious pathogens in vivo.

IL-18, although antiallergic when administered with IL-12, stimulates IL-4 and histamine release by basophils

IL-18 is a proinflammatory cytokine that plays an important role in natural killer cell activation and T helper 1 (Th1) cell responses. Mast cells and basophils are major inducers and effectors of allergic inflammation. Here we show that basophils and mast cells derived by culture of bone marrow cells with IL-3 for 10 days express IL-18Ralpha chain and that basophils produce large amounts of IL-4 and IL-13 in response to stimulation with IL-3 and IL-18. Injection of IL-12 and IL-18 inhibits IgE production in helminth-infected wild-type mice and abolishes the capacity of their basophils to produce IL-4 and IL-13 in response to stimulation either with IL-3 and IL-18 or with FcepsilonR cross-linkage. By contrast, this combination of cytokines actually increases IgE levels in helminth-infected IFN-gamma(-/-) mice and enhances IL-4 and IL-13 production by their basophils. Furthermore, injection of IL-18 alone enhances basophil production of IL-4 and histamine both in wild-type and IFN-gamma(-/-) mice. Thus, IL-18 has the potential to stimulate basophils but, when given with IL-12, exhibits an antiallergic action in vivo.

The phylogeny of acetic acid bacteria based on the partial sequences of 16S ribosomal RNA: the elevation of the subgenus Gluconoacetobacter to the generic level

Thirty-six strains of acetic acid bacteria classified in the genera Acetobacter, Gluconobacter, and Acidomonas were examined for their partial base sequences in positions 1220 through 1375, 156 bases, of 16S rRNA. The strains of the Q10-equipped Gluconobacter species examined were divided into two subgroups, which included the type strains of Gluconobacter oxydans, the type species of the genus Gluconobacter, and of a second species, Gluconobacter cerinus, respectively. The base differences numbered four between the two type strains. The strains of the Q9-equipped species examined classified in the type subgenus Acetobacter of the genus Acetobacter were not very distant phylogenetically from those of the genus Gluconobacter. The calculated number of base differences was 9-6 between the type strains of G. oxydans and G. cerinus and the type strains of Acetobacter aceti and Acetobacter pasteurianus. In contrast, the strains of the Q10-equipped species examined classified in the subgenus Gluconoacetobacter of the genus Acetobacter were very distant phylogenetically from those of the Acetobacter and Gluconobacter species mentioned above. The number of base differences was calculated to be 14-8. Furthermore, the strains of the methanol-assimilating, Q10-equipped species of the genus Acidomonas examined were located in phylogenetically isolated positions. The type strain of Acidomonas methanolica (identical to Acetobacter methanolicus), the type species of the genus Acidomonas, had 16-9 base differences. The data obtained here indicated that the members of the subgenus Gluconoacetobacter of the genus Acetobacter can be distinguished at the generic level. The new genus Gluconoacetobacter was proposed with the type species, Gluconoacetobacter liquefaciens, in recognition of the genus Acidomonas along with the genera Acetobacter and Gluconobacter in the classification of the acetic acid bacteria.

Cellular responses to bacterial cell wall components are mediated through MyD88-dependent signaling cascades

MyD88 is an adaptor molecule essential for signaling via the Toll-like receptor (TLR)/IL-1 receptor family. TLR4 is a member of the TLR family and a point mutation in the Tlr4 gene causes hyporesponsiveness to lipopolysaccharide (LPS) in C3H/HeJ mice. We have previously shown that both TLR4- and MyD88-deficient mice are hyporesponsive to LPS. In this study we examined the responsiveness of these two knockout mice to various bacterial cell wall components. Cells from TLR4-deficient mice responded to several kinds of LPS, peptidoglycan and crude cell wall preparation from Gram-positive bacteria and mycobacterial lysates. In contrast, macrophages and splenocytes from MyD88-deficient mice did not respond to any of the bacterial components we tested. These results show that MyD88 is essential for the cellular response to bacterial cell wall components.

Development and evaluation of a multiplex PCR assay for rapid detection of toxigenic Vibrio cholerae O1 and O139

A multiplex polymerase chain reaction assay was developed for concurrent detection of rfb sequences specific for the O1 and the O139 serogroups of Vibrio cholerae and for ctxA specific sequences. The multiplex PCR assay was found to be highly specific and sensitive and was capable of detecting 65 cfu and 200 cfu per assay of V. cholerae O1 and O139, respectively. Evaluation of the multiplex PCR assay using 121 stool samples from patients admitted to the Infectious Diseases Hospital, Calcutta, showed the assay to be 100% sensitive and 95.2% specific when the culture method was taken as the standard. In addition to the 38 PCR positive stool samples, an additional four samples which were negative by culture method but positive by PCR assay belonged to the O139 serogroup. All the 38 stool samples positive for either O1 or O139 serogroup by PCR assay were also positive for the ctxA amplicon indicating that the O1 and O139 V. cholerae strains have the genetic potential of producing cholera toxin.

Impact of siderophore production on Pseudomonas aeruginosa infections in immunosuppressed mice

Pseudomonas aeruginosa produces siderophores, pyoverdin and pyochelin, for high-affinity iron uptake. To investigate their contribution to P. aeruginosa infections, we constructed allelic exchange mutants from strain PAO1 which were deficient in producing one or both of the siderophores. When inoculated into the calf muscles of immunosuppressed mice, pyochelin-deficient and pyoverdin-deficient mutants grew and killed the animals as efficiently as PAO1. In contrast, the pyochelin- and pyoverdin-deficient (double) mutant did not show lethal virulence, although it did infect the muscles. On the other hand, when inoculated intranasally, all mutants grew in the lungs and killed immunosuppressed mice. Compared with PAO1, however, the pyoverdin-deficient mutant and the double mutant grew poorly in the lungs, and the latter was significantly attenuated for virulence. Irrespective of the inoculation route, the pyoverdin-deficient and doubly deficient mutants detected in the blood were significantly less numerous than PAO1. Additionally, in vitro examination demonstrated that the growth of the double mutant was extremely reduced under a free-iron-restricted condition with apotransferrin but that the growth reduction was completely canceled by supplementation with hemoglobin as a heme source. These results suggest that both pyoverdin and pyochelin are required for efficient bacterial growth and full expression of virulence in P. aeruginosa infection, although pyoverdin may be comparatively more important for bacterial growth and dissemination. However, the siderophores were not always required for infection. It is possible that non-siderophore-mediated iron acquisition, such as via heme uptake, might also play an important role in P. aeruginosa infections.

End-to-side neurorrhaphy with removal of the epineurial sheath: an experimental study in rats

Terminolateral neurorrhaphies were used up to the beginning of this century. After that, they were no longer reported. We tested the efficacy of a new type of end-to-side neurorrhaphy. A group of 20 rats had the peroneal nerve sectioned, and the distal ending was sutured to the lateral face of the tibial nerve after removing a small epineural window. All experiments were made on the right side, the left one remaining untouched in half the animals of each group. The other half was denervated by sectioning and inverting the endings of the peroneal nerves. In this way, tibial cranial muscles were either normal or denervated on the left side and reinnervated through end-to-side neurorrhaphies on the right side. After 7.8 months, the animals were subjected to electrophysiologic tests, sacrificed, and the nerves and muscles were taken for histologic examination. A response of the tibial cranial muscle was obtained in 90 percent of the animals. The distal ending of the peroneal nerve showed an average of 861 nerve fibers. The average areas of the reinnervated tibial cranial muscles were (microns 2) 1617.81 for M2n (when the contralateral side was normal) and 1579.19 for M2d (when the contralateral was denervated). We conclude that the terminolateral neurorrhaphy is functional, conducting electrical stimuli and allowing the passage of axons from the lateral surface of a healthy nerve, to reconstitute the distal segment of a sectioned nerve. The absence of an incision on the axons of the donor nerve was no impediment to axonal regeneration or to the passage of electrical stimuli. The results demonstrate the possibility of using end-to-side and terminolateral neurorrhaphies for reconstituting neural lesions when only a distal end is available; the reinnervation can be obtained from the lateral face of a healthy nerve.

Lipopolysaccharide-induced IL-18 secretion from murine Kupffer cells independently of myeloid differentiation factor 88 that is critically involved in induction of production of IL-12 and IL-1beta

IL-18, produced as biologically inactive precursor, is secreted from LPS-stimulated macrophages after cleavage by caspase-1. In this study, we investigated the mechanism underlying caspase-1-mediated IL-18 secretion. Kupffer cells constantly stored IL-18 and constitutively expressed caspase-1. Inhibition of new protein synthesis only slightly reduced IL-18 secretion, while it decreased and abrogated their IL-1beta and IL-12 secretion, respectively. Kupffer cells deficient in Toll-like receptor (TLR) 4, an LPS-signaling receptor, did not secrete IL-18, IL-1beta, and IL-12 upon LPS stimulation. In contrast, Kupffer cells lacking myeloid differentiation factor 88 (MyD88), an adaptor molecule for TLR-mediated-signaling, secreted IL-18 without IL-1beta and IL-12 production in a caspase-1-dependent and de novo synthesis-independent manner. These results indicate that MyD88 is essential for IL-12 and IL-1beta production from Kupffer cells while their IL-18 secretion is mediated via activation of endogenous caspase-1 without de novo protein synthesis in a MyD88-independent fashion after stimulation with LPS. In addition, infection with Listeria monocytogenes, products of which have the capacity to activate TLR, increased serum levels of IL-18 in wild-type and MyD88-deficient mice but not in caspase-1-deficient mice, whereas it induced elevation of serum levels of IL-12 in both wild-type and caspase-1-deficient mice but not in MyD88-deficient mice. Taken together, these results suggested caspase-1-dependent, MyD88-independent IL-18 release in bacterial infection.

Interplay between efflux pumps may provide either additive or multiplicative effects on drug resistance

The effects of simultaneous expression of several efflux pumps on antibiotic resistance were investigated in Escherichia coli and Pseudomonas aeruginosa. Several combinations of efflux pumps have been studied: (i) simultaneous expression of a single-component efflux pump, which exports antibiotics into the periplasm, in combination with a multicomponent efflux pump that accomplishes efflux directly into the external medium; (ii) simultaneous expression of two single-component pumps; and (iii) simultaneous expression of two multicomponent pumps. It was found that when efflux pumps of different structural types were combined in the same cell (the first case), the observed antibiotic resistance was much higher than that conferred by each of the pumps expressed singly. Simultaneous expression of pairs of single-component or multicomponent efflux pumps (the second and third cases) did not produce strong increases in antibiotic resistance.

Use of a genetic approach to evaluate the consequences of inhibition of efflux pumps in Pseudomonas aeruginosa

Drug efflux pumps in Pseudomonas aeruginosa were evaluated as potential targets for antibacterial therapy. The potential effects of pump inhibition on susceptibility to fluoroquinolone antibiotics were studied with isogenic strains that overexpress or lack individual efflux pumps and that have various combinations of efflux- and target-mediated mutations. Deletions in three efflux pump operons were constructed. As expected, deletion of the MexAB-OprM efflux pump decreased resistance to fluoroquinolones in the wild-type P. aeruginosa (16-fold reduction for levofloxacin [LVX]) or in the strain that overexpressed mexAB-oprM operon (64-fold reduction for LVX). In addition to that, resistance to LVX was significantly reduced even for the strains carrying target mutations (64-fold for strains for which LVX MICs were >4 microg/ml). We also studied the frequencies of emergence of LVX-resistant variants from different deletion mutants and the wild-type strain. Deletion of individual pumps or pairs of the pumps did not significantly affect the frequency of emergence of resistant variants (at 4x the MIC for the wild-type strain) compared to that for the wild type (10(-6) to 10(-7)). In the case of the strain with a triple deletion, the frequency of spontaneous mutants was undetectable (<10(-11)). In summary, inhibition of drug efflux pumps would (i) significantly decrease the level of intrinsic resistance, (ii) reverse acquired resistance, and (iii) result in a decreased frequency of emergence of P. aeruginosa strains highly resistant to fluoroquinolones in clinical settings.

Two end-to-side neurorrhaphies and nerve graft with removal of the epineural sheath: experimental study in rats

We have studied a new type of end-to-side nerve repair in rats. The healthy (donor) nerve was not divided but an epineural window was created. In our experiment, a nerve graft bridged the tibial nerve to the distal end of the divided peroneal nerve. Electrophysiological studies showed electrical impulses conducted through both end-to-side nerve junctions. Histological studies demonstrated axons leaving the lateral surface of the healthy (donor) nerve. Based on these observations, we suggest that end-to-side neurorrhaphy from a healthy nerve may bridge a neural deficit.

Contrasting action of IL-12 and IL-18 in the development of dextran sodium sulphate colitis in mice

BACKGROUND

Interleukin (IL)-12 and IL-18 are major interferon (IFN)-gamma-inducing factors that collaborate with each other. The present study was conducted to determine the distinct roles of IL-12 and IL-18 in the development of dextran sulphate sodium (DSS) colitis in mice.

METHODS

Colitis was induced in IL-12p35(-/-), IL-18(-/-), IL-18 receptor(-/-) and control mice with DSS. Clinical and histopathological analysis was conducted using survival rate, weight loss score, diarrhoea score, bloody stool score and histological score. In addition, cytokine production by lamina propria mononuclear cells (LPMCs) was examined using the specific enzyme-linked immunoassay.

RESULTS

IL-12p35(-/-) mice developed only a mild disease associated with no lethality and few histopathological abnormalities. In contrast, IL-18(-/-) and IL-18R(-/-) mice developed more severe colitis associated with high lethality and more histopathological abnormalities compared with control mice. LPMCs from DSS-fed IL-18(-/-) mice produced significantly higher amounts of IFN-gamma, while LPMCs from DSS-fed IL-12(-/-) mice produced lower amounts of IFN-gamma and tumour necrosis factor (TNF)-alpha compared with control mice.

CONCLUSION

These results suggest that IL-18 might function with manners different from IL-12 at some pathological conditions in the development of colitis.

Comparison of inhibition of Escherichia coli topoisomerase IV by quinolones with DNA gyrase inhibition

In order to examine the inhibitory activities of quinolones against topoisomerase IV, both subunits of this enzyme, ParC and ParE, were purified from Escherichia coli. The specific activity of topoisomerase IV decatenation was found to be more than five times greater than that of topoisomerase IV relaxation. Thus, the decatenation activity of topoisomerase IV seems the most relevant activity for use in studies of drug inhibition of this enzyme. Although topoisomerase IV was less sensitive to quinolones than DNA gyrase, the 50% inhibitory concentrations for decatenation were significantly lower than those for type I topoisomerases. Moreover, there was a positive correlation between the inhibitory activity against topoisomerase IV decatenation and that for DNA gyrase supercoiling. These results imply that topoisomerase IV could be a target for the quinolones in intact bacteria and that quinolones could inhibit not only supercoiling of DNA gyrase but also decatenation of topoisomerase IV when high concentrations of drug exist in bacterial cells.

Identification and quantification of chlorinated bisphenol A in wastewater from wastepaper recycling plants

Chlorinated derivatives of bisphenol A were detected in the final effluents of eight paper manufacturing plants in Shizuoka, Japan, where thermal paper and/or other printed paper is used as the raw material. Their amounts were determined by gas chromatography/mass spectrometry (GC/MS) after treatment with N, O-bis(trimethylsilyl)trifluoroacetamide, and ranged from traces to 2.0 microg/l. They are likely produced by chlorination of bisphenol A, which was released into the effluents from the pulping process of wastepaper, during or after bleaching with chlorine.