thuringiensis. We thank Didier Lereclus for kindly providing the plasmid pRN5101. This research was supported by grant NSC 95-2311-B-010-005 Selleck LDK378 from the National Science Council and a grant, Aim for the Top University Plan, from the Ministry of Education of China. Table S1. Oligonucleotides used in this study. 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. “
“In the present work, the adhesion of 43 human lactobacilli isolates to mucin has been studied. The most adherent strains were selected, and their capacities to adhere to three epithelial cell lines were studied. All intestinal strains and one vaginal isolate adhered to HT-29 cells. The latter was the most adherent to Caco-2 cells, although two of the intestinal isolates were also highly adherent. Moreover, five of the eight strains strongly adhered to HeLa cells. The binding of an Actinomyces neuii clinical isolate to HeLa cells was enhanced by two of the lactobacilli and by their secreted proteins,

while those of another two strains almost abolished it. None of the strains were able to interfere MK0683 cost with the adhesion of Candida albicans to HeLa cells. The components of the extracellular proteome of all strains were identified by MALDI-TOF/MS. Among them, a collagen-binding A precursor and aggregation-promoting factor–like proteins are suggested to participate on adhesion to Caco-2 and HeLa cells, respectively. In this way, several proteins with LysM domains might explain the ability of some bacterial supernatants to block Cyclic nucleotide phosphodiesterase A. neuii adhesion to HeLa cell cultures. Finally, glyceraldehyde 3-phosphate dehydrogenase (GAPDH) could explain the good adhesion of some strains to mucin. The balance between the different microorganisms inhabiting the human vagina is important for the maintenance of its homeostasis, affecting directly the health status of the woman. Among the resident microorganisms, the

Lactobacillus isolates represent at least 70% of the bacteria sampled (Redondo-López et al., 1990; Martín et al., 2008b) being the most dominant L. crispatus, L. jensenii, and L. gasseri and in less extent L. salivarius, L. vaginalis, and L. iners (Boyd et al., 2005; Martín et al., 2008a, b). Because of their relative abundance, lactobacilli have been proposed as probiotics to be used against the establishment and overgrowth of pathogenic microorganisms in the vagina. These benefits would be exerted by two different mechanisms: (i) competition for attachment sites on epithelial cells and pathogen co-aggregation and (ii) production of antimicrobial compounds (Lepargneur & Rousseau, 2002). The first leads to formation of a biofilm that prevents the colonization by undesirable microorganisms (Antonio et al., 2005).

S4), as defined from the annotation of the genome databases at the Broad Institute of Harvard and MIT and the Aspergillus Genome Database at Stanford (Arnaud et al., 2010). All genes were individually deleted by replacing the entire ORFs using gene-targeting substrates based on the pyrG marker from A. fumigatus for

selection. Before analyzing the deletion mutant strains, the pyrG marker was excised by direct repeat recombination (Nielsen et al., 2006) in each case. This was carried out to ensure that the analyses of individual mutant strains were comparable to and not influenced by differences in the primary metabolism due to gene cluster-specific expression levels of the pyrG marker. All 32 deletion mutant Selleckchem Ipilimumab strains (see Table S4) were viable and able to sporulate, showing that none of the 32 genes are essential for growth and that no polyketide product is essential for conidiation. As expected, the one strain carrying the wAΔ mutation formed white conidiospores as it fails to produce the naphthopyrone, YWA1, the precursor

of green conidial pigment (Watanabe, 1998; Watanabe et al., 1999). In addition to wA, eight additional learn more PKS genes have previously been linked to metabolites. In our analysis, key compounds representing four of these gene clusters could be detected: monodictyphenone (1) (observed on RTO, YES and CY20), orsellinic acid (2) (observed on YES, CY20, RT, CYAs and CYA), emericellamide (A) (3) (observed on all media) and sterigmatocystin Interleukin-3 receptor (4) (observed on RTO, CYAs and CYA). To verify the previously published gene links to these compounds, we individually compared the metabolic profiles of the reference strain to the corresponding profiles obtained with the single PKS gene deletion mutant strains. In agreement with previous analyses, these four compounds disappeared in mdpG (Bok et al., 2009), orsA (Schroeckh

et al., 2009), easB (Chiang et al., 2008) and stcA (Yu & Leonard, 1995) deletion strains of our library (Fig. S5). Compounds resulting from the remaining four PKS genes were identified by activating the gene clusters by controlled expression of the transcription factor gene in the cluster (Bergmann et al., 2007; Chiang et al., 2009) or by deleting sumO that influences regulation of biological processes at many different levels (Szewczyk et al., 2008). Expression from these clusters is apparently not triggered by growth on any of our media, and natural conditions provoking their activation remain to be discovered. Next, we performed a comparison of the metabolite profiles from the 32 deletion mutants with those obtained with the reference strain with the aim of uncovering novel genetic links between PKS genes and polyketides. The most significant changes are described below. First we focused our attention on the most prominent compound produced on RTO, YES, CY20 and RT media, which eluted as a broad peak around 7.2 min. This compound completely disappeared in the mdpGΔ strain (Fig. 2 and Fig. S6).

With the exception of Helicobacter pylori, all currently identified DNA uptake systems use type IV pili, type II secretion systems, or uptake machinery related to these secretion systems (reviewed in Chen & Dubnau, 2004). Neisseria gonorrhoeae use a Type IV pilus for transformation and are constitutively competent Gemcitabine in vitro for DNA transformation (Sparling, 1966). The lack of stable clonal lineages indicates that exchange of chromosomal DNA is common between N. gonorrhoeae strains (Smith et al., 1993). DNA transformation is a multi-step process that includes

DNA binding, DNA uptake into the periplasm and cytoplasm, and DNA recombination into the chromosome (reviewed in Hamilton & Dillard, 2006). Neisseria species have been shown to preferentially take up and transform their own DNA by virtue of a non-palindromic Neisseria-specific DNA uptake sequence (DUS) (Elkins et al., 1991). There are two forms of the DUS, DUS10 (5′-GCCGTCTGAA) and DUS12 (5′-ATGCCGTCTGAA), which are necessary for

the most efficient transformation into Neisseria, with the DUS12 sequence showing the greatest efficiency (Smith et al., 1999; Ambur et al., 2007). Neisseria genomes are enriched for the DUS10 and DUS12 sequences, and many reports have demonstrated increased DNA uptake and transformation with DNA fragments containing one or both DUS sequences (Goodman & Scocca, 1988; Ambur et al., 2007; Duffin & Seifert, 2010). It appears that the DUS10 and DUS12 sequences function similarly but that the DUS12 provides a small increase in transformation efficiency. The accepted model of DUS action Epacadostat molecular weight invokes the DUS binding to a putative outer membrane

receptor leading to enhanced DNA transport into the periplasm, although the mechanism is uncertain and no receptor has been identified. Recently, we proposed a more complex role for the DUS during transformation, which includes undefined roles within the periplasm (Duffin & Seifert, 2010). Most investigations into transformation of N. gonorrhoeae have used double-stranded DNA (dsDNA) substrates, but a few have utilized single-stranded DNA (ssDNA) substrates to study transformation. Several observations suggest that ssDNA is an important substrate for transformation Protein kinase N1 including: (1) single-stranded chromosomal DNA is secreted by the Neisseria type IV secretion system (Salgado-Pabon et al., 2007) and co-culture experiments show that this secreted DNA transforms recipient cells efficiently (Dillard & Seifert, 2001); (2) the secretin PilQ, which is required for DNA uptake, binds ssDNA better than dsDNA (Assalkhou et al., 2007); and (3) ssDNA has been reported to transform at levels similar to dsDNA (Stein, 1991). No reports have investigated the potential role of the two forms of the non-palindromic DUS in ssDNA transformation. We purified single-stranded transforming DNA carrying each sequence of the DUS12. These ssDNA substrates were used to transform two laboratory strains of N.

For the plus-enzyme control, an UMP assay was performed in the absence of inhibitor. In the minus-enzyme control, sterile water instead of enzyme was used. The IC50s were calculated using a linear regression standard curve to predict the concentration of compound needed for 50% inhibition. One unit of activity was defined as the amount of enzyme required to degrade 0.1 nmol of ATP in selleck chemical 120 min at 30 °C under the conditions described above. The minimum inhibitory concentrations (MICs) were determined by a standard microdilution broth method (National Committee for Clinical Laboratory Standards, 2003) with slight modifications. Briefly, the inoculum

size was ~5 × 105 CFU mL−1 in the final assay volume of 50 μL. The microdilution plates inoculated with bacteria were incubated at 35 °C for 18–20 h, and

the MIC was determined as the lowest concentration of the compound that completely inhibited the viable growth of the organism in the microdilution wells. Equilibrium analysis by SPR was performed using a Biacore3000 and the CM5 sensor chip (GE Healthcare MG-132 research buy Japan). SpPyrH was covalently coupled to CM5 using a standard amine coupling method according to the manufacturer’s protocol. Briefly, CM5 was activated by injecting a mixture of 20 mM N-hydroxysuccinimide (NHS) and 80 mM 1-ethyl-3- (3-diethylaminopropyl) carbodiimide hydrochloride. After being diluted tenfold with acetate buffer (pH 4.8), SpPyrH (0.1 mg mL−1) was injected at 10 μL min−1 for 7 min and then CM5 was inactivated by 1 M ethanolamine hydrochloride

(pH 8.5) to block the residual NHS ester groups. Running buffer (10 mM Hepes (pH7.4), 150 mM NaCl, 3 mM EDTA, 0.005% Surfactant (GE Healthcare Japan), 5% DMSO) was used in all binding experiments. All compounds dissolved in DMSO were diluted 1 : 20 with the running buffer without 5% DMSO. The samples were injected at 30 μL min−1 SPTLC1 for 2 min. The response was measured in resonance units (RU), and data analysis of the sensorgrams was performed using BIAevaluation software ver. 3.1 and the response at the equilibrium phase of interaction was obtained using the software program ‘equilibrium analysis model’. To obtain recombinant PyrH proteins, the SpPyrH or HiPyrH, each tagged with 6xHis at NH2-terminus, was expressed in E. coli and then purified using the Ni-affinity resin. When purified SpPyrH or HiPyrH protein was examined by SDS–PAGE followed by Coomassie staining, a prominent band was detected of 29.2 or 28.3 kDa in size, respectively, which was deduced as the molecular weight of SpPyrH or HiPyrH (Fig. 1a and c). These proteins were also detected by Western blotting analysis with anti-6xHis antibody, suggesting that each of these proteins is an authentic target protein (Fig. 1b and d).

For the plus-enzyme control, an UMP assay was performed in the absence of inhibitor. In the minus-enzyme control, sterile water instead of enzyme was used. The IC50s were calculated using a linear regression standard curve to predict the concentration of compound needed for 50% inhibition. One unit of activity was defined as the amount of enzyme required to degrade 0.1 nmol of ATP in Bleomycin 120 min at 30 °C under the conditions described above. The minimum inhibitory concentrations (MICs) were determined by a standard microdilution broth method (National Committee for Clinical Laboratory Standards, 2003) with slight modifications. Briefly, the inoculum

size was ~5 × 105 CFU mL−1 in the final assay volume of 50 μL. The microdilution plates inoculated with bacteria were incubated at 35 °C for 18–20 h, and

the MIC was determined as the lowest concentration of the compound that completely inhibited the viable growth of the organism in the microdilution wells. Equilibrium analysis by SPR was performed using a Biacore3000 and the CM5 sensor chip (GE Healthcare learn more Japan). SpPyrH was covalently coupled to CM5 using a standard amine coupling method according to the manufacturer’s protocol. Briefly, CM5 was activated by injecting a mixture of 20 mM N-hydroxysuccinimide (NHS) and 80 mM 1-ethyl-3- (3-diethylaminopropyl) carbodiimide hydrochloride. After being diluted tenfold with acetate buffer (pH 4.8), SpPyrH (0.1 mg mL−1) was injected at 10 μL min−1 for 7 min and then CM5 was inactivated by 1 M ethanolamine hydrochloride

(pH 8.5) to block the residual NHS ester groups. Running buffer (10 mM Hepes (pH7.4), 150 mM NaCl, 3 mM EDTA, 0.005% Surfactant (GE Healthcare Japan), 5% DMSO) was used in all binding experiments. All compounds dissolved in DMSO were diluted 1 : 20 with the running buffer without 5% DMSO. The samples were injected at 30 μL min−1 DNA ligase for 2 min. The response was measured in resonance units (RU), and data analysis of the sensorgrams was performed using BIAevaluation software ver. 3.1 and the response at the equilibrium phase of interaction was obtained using the software program ‘equilibrium analysis model’. To obtain recombinant PyrH proteins, the SpPyrH or HiPyrH, each tagged with 6xHis at NH2-terminus, was expressed in E. coli and then purified using the Ni-affinity resin. When purified SpPyrH or HiPyrH protein was examined by SDS–PAGE followed by Coomassie staining, a prominent band was detected of 29.2 or 28.3 kDa in size, respectively, which was deduced as the molecular weight of SpPyrH or HiPyrH (Fig. 1a and c). These proteins were also detected by Western blotting analysis with anti-6xHis antibody, suggesting that each of these proteins is an authentic target protein (Fig. 1b and d).

Rates of LCGU in the brains of these three animals in response to saline injections were no different from the drug-naïve controls, which were housed in similar conditions and handled in the same fashion; thus their data were combined. The 2DG procedure was conducted in the animal’s home cage and was initiated by means of an intravenous infusion of a pulse of 2DG (75 μCi/kg; specific activity 55 mCi/mmol; New England Nuclear, Boston, MA, USA) through the jugular venous catheter (via which self-administration had previously occurred). Sunitinib clinical trial Timed femoral arterial blood samples were collected over the next 45 min and immediately centrifuged.

Rates of LCGU in cocaine self-administering rats were compared VEGFR inhibitor with those obtained from control rats. Plasma concentrations of 2DG were determined by liquid scintillation counting (Beckman Instruments, Pasadena, CA, USA), while plasma glucose levels were determined by means of a Beckman Glucose Analyzer

II (Beckman Instruments). Immediately after the 45-min sample, animals were killed by administration of intravenous pentobarbital (100 mg/kg). Brains were rapidly removed, frozen in isopentane at −45 °C and stored at −80 °C until sectioning. Brains were sectioned coronally (20 μm) in a cryostat maintained at −20 °C, collected on glass coverslips and immediately transferred to a hot plate (60 °C) to dry. Coverslips were apposed to Kodak EMC film for 13-17 days along with a set of calibrated [14C]methylmethacrylate standards (Amersham,

IL, USA) previously calibrated for their equivalent wet weight 14C concentrations. Films were developed in GBX developer (Kodak, New York, USA). Autoradiograms were analysed by quantitative densitometry with a computerized image analysis system (MCID, Imaging Research, Ontario, Canada). Tissue 14C concentrations were determined from densitometric filipin analysis of autoradiograms of the calibrated standards. Rates of glucose utilization were then calculated using the optical densities and a calibration curve obtained from local 14C tissue concentrations, time-courses of the plasma glucose and 14C concentrations, and the constants according to the operational equation of the 2DG method (Sokoloff et al., 1977). Glucose utilization measurements were determined for 20 discrete brain regions according to the rat brain atlas of Paxinos & Watson (1998). Each brain region was analysed bilaterally in a minimum of five brain sections per animal. Graph Pad Prism (version 4, La Jolla, CA, USA) was used to statistically analyse data sets and create graphs. Locomotor data were subjected to a two-way analysis of variance (anova) with experimental group and time as the factors, followed by planned Bonferroni’s tests for multiple comparisons.

Rates of LCGU in the brains of these three animals in response to saline injections were no different from the drug-naïve controls, which were housed in similar conditions and handled in the same fashion; thus their data were combined. The 2DG procedure was conducted in the animal’s home cage and was initiated by means of an intravenous infusion of a pulse of 2DG (75 μCi/kg; specific activity 55 mCi/mmol; New England Nuclear, Boston, MA, USA) through the jugular venous catheter (via which self-administration had previously occurred). selleck compound Timed femoral arterial blood samples were collected over the next 45 min and immediately centrifuged.

Rates of LCGU in cocaine self-administering rats were compared RG7420 mw with those obtained from control rats. Plasma concentrations of 2DG were determined by liquid scintillation counting (Beckman Instruments, Pasadena, CA, USA), while plasma glucose levels were determined by means of a Beckman Glucose Analyzer

II (Beckman Instruments). Immediately after the 45-min sample, animals were killed by administration of intravenous pentobarbital (100 mg/kg). Brains were rapidly removed, frozen in isopentane at −45 °C and stored at −80 °C until sectioning. Brains were sectioned coronally (20 μm) in a cryostat maintained at −20 °C, collected on glass coverslips and immediately transferred to a hot plate (60 °C) to dry. Coverslips were apposed to Kodak EMC film for 13-17 days along with a set of calibrated [14C]methylmethacrylate standards (Amersham,

IL, USA) previously calibrated for their equivalent wet weight 14C concentrations. Films were developed in GBX developer (Kodak, New York, USA). Autoradiograms were analysed by quantitative densitometry with a computerized image analysis system (MCID, Imaging Research, Ontario, Canada). Tissue 14C concentrations were determined from densitometric Oxymatrine analysis of autoradiograms of the calibrated standards. Rates of glucose utilization were then calculated using the optical densities and a calibration curve obtained from local 14C tissue concentrations, time-courses of the plasma glucose and 14C concentrations, and the constants according to the operational equation of the 2DG method (Sokoloff et al., 1977). Glucose utilization measurements were determined for 20 discrete brain regions according to the rat brain atlas of Paxinos & Watson (1998). Each brain region was analysed bilaterally in a minimum of five brain sections per animal. Graph Pad Prism (version 4, La Jolla, CA, USA) was used to statistically analyse data sets and create graphs. Locomotor data were subjected to a two-way analysis of variance (anova) with experimental group and time as the factors, followed by planned Bonferroni’s tests for multiple comparisons.

The suspension was centrifuged at 20 000 g and 4 °C for 10 min and the supernatant was extracted once with chloroform to remove residual phenol. The DNA was precipitated with isopropanol, washed with 70% ethanol, Epigenetic pathway inhibitor dried and resuspended in TE buffer. Plasmid DNA from Escherichia coli was isolated using the Plasmid Midi Kit (Qiagen). Plasmids from E.

faecalis were purified according to the preparative protocol for large-scale plasmid isolation (Anderson & McKay, 1983) with slight modifications. In order to insert a 34-bp random sequence interspaced by tet(M) into pRE25, the integration vector pMH401 was constructed (Fig. 1, Table 1). A 1-kb fragment directly upstream of the stopcodon of the ermB gene was amplified using the primer pair Ins_A2/B (Table 2), the proofreading Phusion polymerase (Finnzymes, Espoo, Finland), and DNA from L. lactis BuRE25 as template. Similarly, a 1-kb fragment downstream of the stopcodon of the ermB gene was amplified using the primers Ins_C and

Ins_D. The two fragments were fused via splicing by overlap extension PCR using the 34-bp overlapping region introduced in the primers Ins_B and Ins_C (Table 2, underlined). PCR was then performed on the fused fragments using primers Ins_A2 and Ins_D and 2 ×taq PCR Master Mix (Fermentas, Le-Mont-sur-Lausanne, Switzerland). The resulting 2120-bp fragment was cloned into the cloning vector pGEM®-T Easy (Promega, Madison) according to the manufacturer’s instructions. The resulting plasmid was acetylcholine designated pMH400, a plasmid containing the 1-kb up- and downstream regions of the stopcodon of the ermB gene, interspaced selleck chemical with a 34-bp random sequence. Subsequently, tet(M) was amplified from E. coli CG120/pAM120 DNA using primers HP14 and HP15 and Phusion DNA polymerase. The

2678-bp fragment obtained was ligated into pMH400 linearized with SwaI. Correct plasmid construction was checked by restriction analyses and by PCR targeting tet(M) using primers HP14 and HP15 (Table 2). The obtained plasmid was designated pMH401 and harbors the 1-kb up- and downstream regions of the stopcodon of the ermB gene interspaced with tet(M) flanked by a 23-bp and an 11-bp random sequence (Fig. 1). Plasmid pMH401 was transferred into L. lactis BuRE25 (Table 1) by electroporation as described previously (Holo & Nes, 1989) and primary integrants were selected on streptococcal regeneration plates (Okamoto et al., 1983) containing 10 μg mL−1 tetracycline. A double-cross-over event results in integration of tet(M) flanked by the two random sequences downstream of the ermB gene in pRE25 (Fig. 1). Therefore, integrants were streaked on brain–heart infusion (BHI) containing 10 μg mL−1 erythromycin and after incubation for 48 h at 30 °C, single colonies were checked for double-cross-over by PCR using the primer pairs Int401_A/F and Int401_G/D. An isolate showing correct PCR pattern was designated L.

The correlation coefficient was calculated using the firing rates and the corresponding behavioral reaction times for each neuron. A total of 42 neurons from dlPFC and 36 neurons from LIP were used for this analysis. Similar neuronal times of target discrimination learn more were observed in the two areas areas (dlPFC, 107 ms; LIP, 105 ms). Average correlation coefficient values were lower (more negative) for LIP neurons than for dlPFC neurons throughout the cue presentation period (Fig. 10A), indicating that a higher firing rate in LIP was more predictive of faster reaction times in the task. Correlation coefficients

were also computed for the 300 ms of the fixation period (−300 to 0 ms from the cue onset) and the 300 ms of the cue period. LIP correlation coefficient of the cue

period was significantly different from zero (Fig. 10B; t-test, t35 = −3.24, P < 0.01). No significant correlation was found in the fixation period of either area and the cue period of dlPFC. The difference between dlPFC and LIP was found to be significant in the cue period (Fig. 10B; t-test, http://www.selleckchem.com/products/PF-2341066.html t76 = 3.71, P < 0.001). The results indicate that correlation between the neuronal activity and the behavioral reaction time is stronger in PPC than in dlPFC. We computed Fano factors for the neurons used for this analysis and found that neuronal response variability was again not significantly different between areas and task epochs Oxalosuccinic acid (two-way anova; F1,152 = 3.25, P > 0.05 for area, F1,152 = 0.01, P > 0.9 for task epoch). Our study investigated the relationship between firing rate and behavioral choice in two cortical areas implicated in the guidance of visual attention.

We analysed data from two different tasks requiring localization of a visual stimulus based on bottom-up factors. Neurons in both dlPFC and LIP are activated by these tasks and demonstrate similar time courses of activation (Katsuki & Constantinidis, 2012a). Firing rate differences between target and distractors become smaller, and the time of target discrimination occurs later, in both areas as the distance of target and distractors increases across the dimension we varied (color), similar to the effects reported from experiments comparing responses to target and distractors from neurons at different distances between the stimuli (Lennert & Martinez-Trujillo, 2011). Despite these similarities in response characteristics in LIP and dlPFC, our results reveal three main differences in the roles of the two areas. First, LIP activity was critical prior to the appearance of the stimulus, correlating significantly with the monkey’s decision regarding the presence of a salient stimulus. Second, this preferential influence of LIP activity on behavior was transient; dlPFC activity predicted behavior later in the trial, after the stimulus appearance.

, 2004; Hofemeister et al., 2004; López et al., 2009). ComX is a quorum-sensing peptide pheromone that triggers the production of surfactin. The lipopeptide is then involved in a paracrine signaling pathway that triggers a subpopulation of

cells to produce an extracellular matrix. Interestingly, the surfactin-producing cells do not produce a matrix themselves, but upstream activation of comX is needed for biofilm production (Magnuson et al., 1994; López et al., 2009). It is still unclear how ComX-producing cells activate surfactin synthesis and how surfactin can then trigger matrix production. In B. subtilis MAPK Inhibitor Library 168 strains, single-base duplications in sfp genes cause impairment in surfactin production (Zeigler et al., 2008). This mutation also C59 wnt ic50 produces losses of swarming and affects the speed of colonization (Julkowska et al., 2005). sfp encodes a phosphopantetheinyl transferase that activates the peptidyl carrier protein domain of the first three subunits (SrfABC) of surfactin synthetase (Quadri et al., 1998). Microorganisms, which require the activation of carrier

proteins involved in secondary metabolic pathways, such as nonribosomal peptide synthetase or polyketide synthase pathways, require the activity of these Sfp-like proteins (Copp et al., 2007). Consequently, in the absence of the Sfp enzyme, B. subtilis cannot synthesize compounds such as surfactin, Anidulafungin (LY303366) which are dependent on nonribosomal peptide synthetase or polyketide synthase-type mechanisms. Bacillus subtilis strain 3610 that carries the intact sfp gene swarms rapidly in symmetrical concentric waves, forming branched dendritic

patterns. This observation was confirmed by Debois et al. (2008), who reported that surfactin molecules with a specific chain length play an important role in the swarming of communities on the agar surface. Although the specific mechanisms of surfactant secretion are unknown, lipopeptide secretion provides a powerful competitive advantage for any species during surface colonization and during competition for resources (Ron & Rosenberg, 2001). For example, surfactin produced by B. subtilis inhibits Streptomyces coelicolor aerial development and causes altered expression of developmental genes (Straight et al., 2006). It has also been established that surfactin is required for the formation of aerial structures on B. subtilis biofilm (Branda et al., 2001). The ecological role of the aerial structures is to increase the spore dispersal capacity. The second and third groups of surfactants produced by B. subtilis are peptides belonging to the iturin and plipastatin–fengycin groups, respectively (Fig. 1). Using HPLC, Ahimou et al. (2000) reported considerable variations in the lipopeptide content of seven B. subtilis strains. Among the three types of lipopeptides, only iturin A was produced by all seven B. subtilis strains.