In a retrospective chart review of patients with HIV infection, Pugliese et al. [83] found the incidence of PAH to be higher in individuals who received HAART compared with those

individuals who only received NRTIs. This result may have arisen from differences in the cohort populations: the HAART cohort may have had more progressed HIV disease as it was defined as individuals MK0683 purchase with a CD4 count of <300 cells/μL and a viral load of >30 000 copies/mL, whereas the NRTI cohort was defined as individuals with stage C2 (CD4 count between 200 and 499 cells/μL and AIDS-defining illness) or greater disease. The reason that HAART does not favourably impact the prevalence of HIV-related PAH is unclear at the present time. We do know from studies that HIV does not directly infect vascular endothelial cells or smooth muscle cells [24]. Hence, the association between HIV and PAH may not be related to viral load or immune status, partially explaining why HAART does not prevent PAH. The results of the case reports reveal that HIV-related PAH Tofacitinib is most common in male patients with an average age of 35 years who contracted HIV via injection drug use or male-to-male sexual activity. Although purely speculative, the increased frequency found in individuals who have used intravenous drugs might be related to foreign

body emboli, the use of amphetamine-based drugs, or the presence of portal hypertension, which might be under-diagnosed given the relatively high prevalence of concomitant hepatitis B and C found in this population [92]. The average CD4 count was around 354 cells/μL and 53% Neratinib in vivo of the patients had been diagnosed with AIDS. There was no relationship identified between CD4 cell count and HIV-related PAH, which is corroborated by other studies [8]. The average time from diagnosis of HIV infection to developing PAH was 4.3 years. These results indicate that HIV-related PAH is a chronic disease that occurs gradually. The physical examination, chest X-ray, ECG and echocardiographic findings mentioned above in HIV-related PAH

are similar to those in other causes of PAH. There are no distinct physical or imaging findings that distinguish HIV-related PAH from other causes of PAH. Furthermore, the histopathological examination reveals that HIV-related PAH is characterized by plexogenic pulmonary arteriopathy similar to primary pulmonary vascular disease. The histopathology of primary pulmonary vascular disease is classified as primary pulmonary arteriopathy (plexiform arteriopathy, thrombotic arteriopathy, isolated medial hypertrophy, and medial hypertrophy with intimal fibrosis), pulmonary veno-occlusive disease and pulmonary capillary haemangiomatosis [93]. Plexogenic pulmonary arteriopathy has also been found in other causes of PAH including cirrhosis of the liver, portal hypertension, connective tissue disorders and congenital cardiac disorders [94].

cenocepacia K56-2 after 24 h of exposure. As shown in Fig. 2a, DHA exhibits a concentration-dependent bacteriostatic activity. Upon exposure to DHA, B. cenocepacia K56-2

cells aggregated and formed clusters (Fig. 2b). Moreover, the highest concentrations of DHA screened (50 and 100 mM) caused not only a significant growth inhibition (80–90%) but also death of B. cenocepacia K56-2 cells (8 log10-unit reduction of viable B. cenocepacia cells) (Fig. 2c). Therefore, these results indicate that DHA has a bacteriostatic/killing activity against B. cenocepacia K56-2. To further confirm the in vitro antibacterial effect of DHA (50 mM), we extended our analysis to one representative strain of each of the 17 Bcc species. In addition, see more we also

included two additional clinical isolates (J2315, AU1054) belonging to the B. cenocepacia species. Figure 3 demonstrates that although there is variation in the extent of the antibiotic effect observed, DHA significantly reduces the growth of all Bcc strains studied (40–100% inhibition). Burkholderia cenocepacia J2315, Burkholderia stabilis LMG14294 and Burkholderia anthinia AU1293 were particularly susceptible to DHA, while Burkholderia vietnamiensis PC259, Burkholderia pyrrocinia BC011 and Burkholderia lata 383 possessed the highest levels of resistance (Fig. 3). To determine whether RG7422 order the observed sensitivity/tolerance of the Bcc isolates to DHA was because of hydrophobic interactions with the bacterial cell membrane, the BATH assay was used (Rosenberg et al., 1980). As shown in Fig. 3, a direct relationship was not observed between the degree of cell surface hydrophobicity and DHA sensitivity/tolerance. The in vivo antimicrobial efficacy of DHA against B. cenocepacia was examined in a G. mellonella caterpillar model system.

To mimic a therapy with DHA, larvae were inoculated with a lethal dose of B. cenocepacia K56-2 followed by the administration of a single dose of DHA (50 mM: 190 mg kg−1), given 6 h after infection. The dose of DHA used was within the limits of dosage used in animal studies (Willumsen et al., 1993; Mizota et al., 2001). As shown in Fig. 4a, over a period of 5 days, the treatment with DHA, compared with an infected Clomifene control group, prolonged the survival of G. mellonella caterpillars (P < 0.01). Uninfected larvae were also inoculated with 50 mM of DHA, and 100% survival was observed after 5 days (Fig. 4a). We also monitored the growth of B. cenocepacia K56-2 in the hemolymph of infected larvae over a period of 24 h postinfection. We observed a reduced bacterial load (2 log10-unit reduction; P < 0.01) in treated group (administration of DHA) compared with control group (Fig. 4b). Finally, by using quantitative real-time RT–PCR, we determined the expression patterns of four immune-related G. mellonella genes encoding antimicrobial peptides at 10 and 21 h postinfection.

’ Here, PI3K targets we used MFCs to assess several behaviors of wild types and TFP/polar flagellum mutants of A. citrulli. TFP and polar flagella are involved in motility, attachment and biofilm formation in different bacterial species (Josenhans & Suerbaum, 2002; Mattick, 2002; Craig et al., 2004). We have demonstrated previously that TFP and polar flagella are involved in the pathogenicity of A. citrulli (Bahar

et al., 2009; O. Bahar and S. Burdman, unpublished results). We also showed that functional TFP are required for biofilm formation of this bacterium on glass and polystyrene surfaces (Bahar et al., 2009). Acidovorax citrulli has the ability to colonize the xylem vessels of melon seedlings (Bahar et al., 2009). Here, studies with xylem-mimicking MFCs revealed an even more drastic effect of TFP on surface attachment and biofilm formation. Under flow conditions, cells of the TFP-null mutant M6-M were unable to attach to the surface. This result was in contrast to findings from conventional assays, where cell attachment and biofilm formation by this mutant were observed to some extent (Bahar et al., 2009). These

results were corroborated by the use of an additional TFP-null mutant in a different A. citrulli strain, W1-A, which is impaired in pilA (major TFP subunit pilin), and showed a behavior similar to that of M6-M in MFCs. The W1-A mutant, generated in the background of wild-type M6, was used in these assays because numerous attempts to generate a pilA mutant in the background of strain M6 were unsuccessful (Bahar et al., 2009). It is important to mention that strain W1 is not a typical A. citrulli strain as it lacks a polar flagellum and selleckchem possesses reduced virulence in comparison with other group II strains of this bacterium

(Bahar et al., 2009). Nevertheless, in this specific study, utilization of almost the W1-A mutant served as an additional means to assess the role of A. citrulli TFP in the MFC system. An interesting phenotype was seen with the hyperpiliated pilT mutant M6-T. In contrast to M6-M, M6-T cells were able to attach to the surface; however, the strength of attachment was significantly weaker than M6, supporting the fact that functional TFP is crucial for surface attachment under flow. Our findings also demonstrate that under flow, functional TFP play an important role in biofilm growth by A. citrulli. In contrast, under the conditions tested, polar flagella appear to be less important for adhesion and biofilm formation of A. citrulli. This statement is supported by the fact that the flagellin mutant M6-flg and wild-type W1 (both lacking flagella) were able to attach to the surface and form a biofilm in a manner similar to that of M6. TFP are well-established virulence determinants of animal pathogenic bacteria, and were recently shown to contribute to the virulence of several phytopathogenic bacteria, including Ralstonia solanacearum, Xanthomonas oryzae pv.

’ Here, OSI-744 molecular weight we used MFCs to assess several behaviors of wild types and TFP/polar flagellum mutants of A. citrulli. TFP and polar flagella are involved in motility, attachment and biofilm formation in different bacterial species (Josenhans & Suerbaum, 2002; Mattick, 2002; Craig et al., 2004). We have demonstrated previously that TFP and polar flagella are involved in the pathogenicity of A. citrulli (Bahar

et al., 2009; O. Bahar and S. Burdman, unpublished results). We also showed that functional TFP are required for biofilm formation of this bacterium on glass and polystyrene surfaces (Bahar et al., 2009). Acidovorax citrulli has the ability to colonize the xylem vessels of melon seedlings (Bahar et al., 2009). Here, studies with xylem-mimicking MFCs revealed an even more drastic effect of TFP on surface attachment and biofilm formation. Under flow conditions, cells of the TFP-null mutant M6-M were unable to attach to the surface. This result was in contrast to findings from conventional assays, where cell attachment and biofilm formation by this mutant were observed to some extent (Bahar et al., 2009). These

results were corroborated by the use of an additional TFP-null mutant in a different A. citrulli strain, W1-A, which is impaired in pilA (major TFP subunit pilin), and showed a behavior similar to that of M6-M in MFCs. The W1-A mutant, generated in the background of wild-type M6, was used in these assays because numerous attempts to generate a pilA mutant in the background of strain M6 were unsuccessful (Bahar et al., 2009). It is important to mention that strain W1 is not a typical A. citrulli strain as it lacks a polar flagellum and Ixazomib in vivo possesses reduced virulence in comparison with other group II strains of this bacterium

(Bahar et al., 2009). Nevertheless, in this specific study, utilization of however the W1-A mutant served as an additional means to assess the role of A. citrulli TFP in the MFC system. An interesting phenotype was seen with the hyperpiliated pilT mutant M6-T. In contrast to M6-M, M6-T cells were able to attach to the surface; however, the strength of attachment was significantly weaker than M6, supporting the fact that functional TFP is crucial for surface attachment under flow. Our findings also demonstrate that under flow, functional TFP play an important role in biofilm growth by A. citrulli. In contrast, under the conditions tested, polar flagella appear to be less important for adhesion and biofilm formation of A. citrulli. This statement is supported by the fact that the flagellin mutant M6-flg and wild-type W1 (both lacking flagella) were able to attach to the surface and form a biofilm in a manner similar to that of M6. TFP are well-established virulence determinants of animal pathogenic bacteria, and were recently shown to contribute to the virulence of several phytopathogenic bacteria, including Ralstonia solanacearum, Xanthomonas oryzae pv.

” Vaccine is then administered alone with delay before seeking further

medical care. This may be too late as injected immunoglobulin will then interfere Epigenetic activity inhibition with the native immune response generated by vaccine administered more than 7 days earlier. This increases the risk of treatment failure.[3] A recent study from Switzerland brought this issue to our attention.[4] Original WHO guidelines stressed the production of long-lasting antibody levels at the expense of reaching the highest possible early immune response capable of killing the virus at the inoculation sites. This, before it attaches itself to nerve endings and starts to ascend centrally. Once the virus enters the nerves, it is in a partly immune-protected environment. In the early 1970s, there were at least four postexposure prophylaxis vaccination schedules in use worldwide. These treatment methods continued the tradition of lengthy injection schedules dating back to days of poorly immunogenic brain-tissue-derived Semple vaccines. Initially, these 3-month treatments also required six clinic visits to be completed.[5] Lack of better understanding of the pathophysiology and immunology of rabies were the reasons for

Ganetespib clinical trial continuing these lengthy regimens. This, even though Dean and Baer had already shown, in animal studies in 1963, that neutralizing the virus at the inoculation sites is possible and can save additional lives.[6] At the turn of the century,

it became apparent that modern tissue and avian culture rabies vaccines are potent BCKDHB and result in long-lasting immune memory.[7] Bitten subjects, even when administered potent vaccines in a timely manner, may still require additional passive immunity (rabies immunoglobulin) to cover the “window period” before vaccine-generated virus-killing antibody appears in circulation. This is not before at least 7 days after start of a vaccine series.[3] Treatment failures, in patients who received vaccine alone or were given immunoglobulin that was not injected into all bite wounds, are still being reported.[8] Vaccination alone is effective in most rabies-exposed subjects. This is due to the fact that only some bites result in early virus invasion into nerves. Virus excretion in saliva varies in rabid dogs and cats and the viral inoculum may range from none to very high levels. We cannot predict which patient will succumb without wound injection and which one might survive with vaccination alone. Many less advanced rabies-endemic countries, being aware of this, have not provided costly immunoglobulins for the public sector. This was documented in the recent Bali rabies epidemic.[9] Risk factors for rabies postexposure treatment failures are high viral load, bite site near peripheral nerve endings, immunocompromised host, and more virulent virus strain.

The order of cue words during each recall was the same as in the foregoing learning trial. Subjects had unlimited time for recall of the target word, LY2835219 in vivo and no feedback was provided. An additional recall test took place ~ 90 min after the encoding phase. Data from one subject were discarded, owing to ceiling performance (100% correct). In the Verbal Learning and Memory Test (the German version of the Rey Auditory Verbal Learning Test) (Helmstaedter et al., 2001),

a list of 15 semantically unrelated German nouns was orally presented five times (by a pre-recorded male voice), with each word presented for 1 s. Each presentation was followed by a free recall test (L1–L5). Immediately after the fifth run, a different word list was presented [interference list (IL)], to be recalled. After recall of the IL, participants were asked to again recall the first learnt word list. Individual free recall performance was assessed by calculating the difference between the number of correctly recalled words and the number of incorrect responses (false positives – recalling a word that did not occur in the target list; perseverations – repeating an already given correct response). In the finger sequence tapping task (Walker et al., 2002), a five-digit

sequence (e.g. 4–2–3–1–4) had to be tapped with the four fingers (excluding the thumb) of the non-dominant hand as accurately and as quickly as Selleckchem Buparlisib possible. During learning, subjects performed on 12 30-s blocks with 30-s breaks in between. During retrieval, they performed on three 30-s blocks, similarly to learning. The sequence was presented continuously on a screen. No immediate feedback was given on pressing a key, but, after each block, the number of correct sequences and the total number of tapped sequences

were presented. The parameters for tSOS were similar to those in Marshall et al. (2006). The stimulating current oscillated between 0 and 250 μA at a frequency of 0.75 Hz. Anodal electrodes (10 mm in diameter) were positioned bilaterally at F3 and F4 (according to the 10–20 system), and reference electrodes were placed at both mastoids. The electrode PD-1 inhibitor resistance was < 5 kΩ. The maximum current density at the stimulation sites reached ~0.318 mA/cm2. tSOS began after 4 min of the first occurrence of continuous non-REM sleep stage 2, and consisted of six to eight 4-min stimulation epochs during non-REM sleep. The number of 4-min stimulation epochs depended on the individual subject’s sleep, as we aimed to apply tSOS only during non-REM sleep. Stimulation periods were separated by stimulation-free intervals of at least 1 min. During these stimulation-free intervals, online sleep scoring was performed to ensure that subjects still showed non-REM sleep stage 2 or SWS. If not (that is, the participant was awake or in sleep stage 1), stimulation was delayed until the subject had again entered non-REM sleep stage 2 for 2 min.

For instance, during the refolding process, β-lactoglobulin refolded into a specific state rich in α-helix before β-sheet formation in the denatured state (Shibayama, 2008). The incorrect refolding of TRH α-helix from the denatured state might disturb the entire protein structure and function of TRH. Alternatively, maintenance of TRH α-helix structure contents after heat denaturation may be related to the PD-0332991 cost structural stability of the amyloidogenic

proteins. Further investigations at atomic level are needed to clarify whether the correct refolding of α-helix contents from the denatured state is essential for the Arrhenius effect. Our findings indicated that the TDH and TRH showed similar hemolytic activity in vitro. Previous reports showed that the expression level of the trh gene (Kanagawa phenomenon-negative

INCB024360 in vivo strains) is much lower than that of the tdh gene (Kishishita et al., 1992; Okuda & Nishibuchi, 1998). These data may also account for the epidemiological finding that larger numbers of patients with TDH-positive strains are reported among the V. parahaemolyticus infections in contrast to those with TRH-positive strains. In this study, we used human red blood cells for bioassay because the Kanagawa phenomenon is the most classical and distinguishable biological assay for TDH-positive and TRH-positive clinical strains. However, TDH is reported to show cytotoxicity on various mammalian cell lines, including intestinal cells. To clarify the entire process of the pathobiology of TDH and TRH, including its amyloidogenic/aggregative properties upon heating or in a hydrophobic membranous environment, future studies will be needed. We are grateful to Dr Takashi Fukui (Laboratory of Microbiology and Immunology, Faculty of Pharmacy, Chiba Institute of Science) for participating in valuable discussions. This study was supported in part by grants-in-aid from the Ministry

of Education, Culture, Sports, Science and Technology (MEXT), Japan; Ministry of Health, Labor and Welfare, Japan; Niclosamide The Foundation for Mother and Child Well-being, Osaka, Japan; and Osaka Research Society for Pediatric Infectious Disease, Osaka, Japan. Fig. S1. Each 0.1 mg mL-1 TDH (A), TRH (B), concanavalin A at pH 5.1 (C) and pH 7.4 (D) was incubated for 20 min at the respective temperature. ThT fluorescence was measured according to the procedures described in Materials and methods. Please note: Wiley-Blackwell is not responsible for the content or functionality of any supporting materials supplied by the authors. Any queries (other than missing material) should be directed to the corresponding author for the article.

PCR 16S rRNA gene analyses identified 18 strains as V. parahaemolyticus with 100% identity, but yielded uncertain identification for 14 isolates. Twenty-one strains were confirmed as V. parahaemolyticus by PCR assays to detect species-specific targets (in Fig. 1 an example of ToxR PCR detection is shown); three strains Caspase cleavage were trh positive. The comparison of biochemical and molecular results (Table 1) showed that, among the 21 V. parahaemolyticus strains, 19 were identified by one or both API systems, but only two of them yielded coherent responses with biochemical features reported by Alsina’s scheme; in particular, API 20E yielded only one false positive (Table 2) and six false negatives,

while API 20NE yielded no false-positive results, but eight false negatives. The results obtained in the present work contribute to the debate about the problematic phenotypic identification of environmental V. parahaemolyticus strains. TCBS agar is the only proven selective medium for Vibrio spp. isolation,

but a large number of marine microorganisms may also grow (Thompson et al., 2004). In this study, the screening phase selected 58% of the analyzed strains as belonging to genus Vibrio. Our results confirm those of Croci et al. (2001), who evidenced how strains isolated from seawater and mussels on TCBS agar were principally vibrios (about 50%) while the remaining were Aeromonas, Pseudomonas, Flavobacterium, Pasteurella and Agrobacterium. API systems and Alsina’s scheme (Alsina & Blanch, 1994a, b) are the most extensively used techniques Pembrolizumab concentration by Italian Laboratories to screen the diversity Branched chain aminotransferase of Vibrio spp. strains associated with marine organisms and their habitats (Croci et al., 2007). However, several authors reported that V. parahaemolyticus phenotypic identification is difficult because of the huge variability of diagnostic features among the species (O’Hara et al., 2003; Thompson et al., 2004 and references therein; Croci et al., 2007) and the molecular analyses considered necessary, either for additional confirmatory testing or for a certain identification method. In our study, the

amplification of the 16S rRNA gene produced misidentifications because of the strictly genetic similarity between V. parahaemolyticus and Vibrio alginolyticus, Vibrio campbelli, Vibrio carchariae and Vibrio harveyi (Dorsch et al., 1992). Molecular confirmation performed through PCR assays for toxR and tlh genes produced the same results in contrast to that reported by Croci et al. (2007), who reported that tlh gene detection yields false-positive identifications. Although different studies highlighted the inadequacy of API systems for Vibrio identification (Dalsgaard et al., 1996; Colodner et al., 2004; Croci et al., 2007), in the research, the use of both API 20E and API 20NE, using bacterial suspensions with a slight modification of the salinity from 0.

These plasmids were introduced into the mobilizer strain E. coli S17-1 and transferred to PAO1 or ΔpqsH using conjugation to yield pqsE-xylE, Cobimetinib supplier ΔpqsH pqsE-xylE and pqsH-xylE strains, as reported earlier (Maseda et al., 2004; Tashiro et al., 2008; Yawata et al., 2008). The insertion of the xylE cassette downstream of the chromosomal pqsE gene or pqsH gene was confirmed by PCR analysis. The activity of the xylE gene product catechol 2,3-dioxygenase (C23O) was measured as described earlier (Toyofuku et al., 2007). The A375 nm was recorded at 30 °C. Specific

activity was defined as the nanomoles of product formed per minute per milligram of protein (nmol min−1 mg−1 protein). Lysis of B. subtilis was examined on a Petri dish using a previously described method (Park et al., 2005). Briefly, LB plates were overlaid with 0.8% top agar containing 105–106 cells mL−1B. subtilis stationary cultures and dried for 1 h. The sterile bottomless stainless-steel cylinders (6.0 mm internal diameter, 8.0 mm outer

diameter, 10.0 mm height) were carefully placed on the agar and 5 μL of P. aeruginosa stationary cultures were spotted in a cylinder to prevent their swarming motilities. Plates were incubated at 30 °C for 24 h. At first, we examined the effect of indole on P. aeruginosa PAO1. PAO1 was cultured aerobically in LB medium in the absence or the presence of indole (0.5, 5, 50 and 500 μM and 5 mM). The growth www.selleckchem.com/products/Adrucil(Fluorouracil).html was notably inhibited with 5 mM, whereas the growth curve did not change significantly when indole at or <500 μM was added (Fig. 2a), suggesting that 500 μM indole is not toxic to P. aeruginosa PAO1. This concentration is similar to the extracellular concentration in the supernatant of E. coli grown in a rich medium (Wang et al., 2001). To investigate the effect of exogenous

indole on MV production, quantities of MVs in the supernatants were measured. Indole inhibited MV production in a dose-dependent manner, with 50 μM indole leading to a 52% decrease Farnesyltransferase in MVs and 500 μM indole leading to an 88% reduction of MVs in the supernatants as compared with a control culture (Fig. 2b). In addition to MV production, pyocyanin production was decreased when 500 μM indole was added (data not shown). It is well known that both MV release and pyocyanin synthesis are regulated by PQS (Mashburn & Whiteley, 2005; Xiao et al., 2006). To investigate whether indole inhibits PQS synthesis, the level of PQS in the supernatants was determined by TLC. Indole inhibited PQS synthesis in a dose-dependent manner, with 500 μM indole leading to a 99% reduction in the PQS levels compared with control cultures (Fig. 2c). These data are consistent with recent published studies showing that indole represses PQS and pyocyanin synthesis in P. aeruginosa (Lee et al., 2009). To further investigate the effect of indole on MV production, we examined the MV production of PQS depletion mutant ΔpqsR in the presence and the absence of 500 μM indole and/or 50 μM PQS. As shown in Fig.

These plasmids were introduced into the mobilizer strain E. coli S17-1 and transferred to PAO1 or ΔpqsH using conjugation to yield pqsE-xylE, Akt activity ΔpqsH pqsE-xylE and pqsH-xylE strains, as reported earlier (Maseda et al., 2004; Tashiro et al., 2008; Yawata et al., 2008). The insertion of the xylE cassette downstream of the chromosomal pqsE gene or pqsH gene was confirmed by PCR analysis. The activity of the xylE gene product catechol 2,3-dioxygenase (C23O) was measured as described earlier (Toyofuku et al., 2007). The A375 nm was recorded at 30 °C. Specific

activity was defined as the nanomoles of product formed per minute per milligram of protein (nmol min−1 mg−1 protein). Lysis of B. subtilis was examined on a Petri dish using a previously described method (Park et al., 2005). Briefly, LB plates were overlaid with 0.8% top agar containing 105–106 cells mL−1B. subtilis stationary cultures and dried for 1 h. The sterile bottomless stainless-steel cylinders (6.0 mm internal diameter, 8.0 mm outer

diameter, 10.0 mm height) were carefully placed on the agar and 5 μL of P. aeruginosa stationary cultures were spotted in a cylinder to prevent their swarming motilities. Plates were incubated at 30 °C for 24 h. At first, we examined the effect of indole on P. aeruginosa PAO1. PAO1 was cultured aerobically in LB medium in the absence or the presence of indole (0.5, 5, 50 and 500 μM and 5 mM). The growth EGFR inhibitor was notably inhibited with 5 mM, whereas the growth curve did not change significantly when indole at or <500 μM was added (Fig. 2a), suggesting that 500 μM indole is not toxic to P. aeruginosa PAO1. This concentration is similar to the extracellular concentration in the supernatant of E. coli grown in a rich medium (Wang et al., 2001). To investigate the effect of exogenous

indole on MV production, quantities of MVs in the supernatants were measured. Indole inhibited MV production in a dose-dependent manner, with 50 μM indole leading to a 52% decrease Suplatast tosilate in MVs and 500 μM indole leading to an 88% reduction of MVs in the supernatants as compared with a control culture (Fig. 2b). In addition to MV production, pyocyanin production was decreased when 500 μM indole was added (data not shown). It is well known that both MV release and pyocyanin synthesis are regulated by PQS (Mashburn & Whiteley, 2005; Xiao et al., 2006). To investigate whether indole inhibits PQS synthesis, the level of PQS in the supernatants was determined by TLC. Indole inhibited PQS synthesis in a dose-dependent manner, with 500 μM indole leading to a 99% reduction in the PQS levels compared with control cultures (Fig. 2c). These data are consistent with recent published studies showing that indole represses PQS and pyocyanin synthesis in P. aeruginosa (Lee et al., 2009). To further investigate the effect of indole on MV production, we examined the MV production of PQS depletion mutant ΔpqsR in the presence and the absence of 500 μM indole and/or 50 μM PQS. As shown in Fig.