Studies in diverse species where adult neurogenesis occurs will r

Studies in diverse species where adult neurogenesis occurs will result in a broader understanding of fundamental mechanisms and how evolutionary processes may have shaped the vertebrate/mammalian condition. “
“10 images from FEMS articles have been selected to show the diversity of visualisation BTK inhibitor cost used in microbiology. “
“Biofilms are bacterial communities enclosed within an extracellular matrix of polysaccharides produced by the bacteria, which adhere to a living or an inert macrosurface. In nature, biofilms constitute a protected growth modality allowing bacteria to survive

in hostile environments. Studies of environmental isolates have revealed a highly ordered, three-dimensional organization of the extracellular matrix, which has important implications for biofilm physiology.

The zone of soil immediately surrounding a plant root where complex biological and ecological processes occur, termed rhizosphere, forms an environment that fulfills the requirements for biofilm formation, including sufficient moisture and supply of nutrients, which are provided by the plant. GSK269962 Biofilm formation on plants appears to be associated with symbiotic and pathogenic responses, but it is unclear how plants regulate the association. Biofilms function as structures resistant against stress factors such as desiccation, UV radiation, predation, and antibiosis, which help create protective niches

for rhizobia. However, the role of biofilms in rhizobial–legume symbiosis remains to be clarified. Here, the mechanisms involved in bacterial biofilm formation and attachment on plant PLEK2 roots, and the relation of these mechanisms to rhizobial function and survival are reviewed. The enriched environment around plant roots allows establishment of interactions between soil bacteria and the roots. These relationships can be beneficial, pathogenic, parasitic, or saprophytic, and exert important effects on plant development and productivity. Microorganisms colonize mineral soil particles as well as plant roots. They may cause plant diseases or, in contrast, produce a wide range of beneficial effects, including biocontrol against pathogens, plant growth promotion through nitrogen fixation, phytohormone production, and mobilization of nutrients. When environmental nitrogen is limited, soil bacteria known as rhizobia interact with roots of leguminous plants to produce symbiotic nodules, inside which atmospheric nitrogen is reduced to ammonium for use by the plant, while the bacteria receive carbohydrates from the plant in a protected environment. Establishment of this symbiosis relies on an exchange of signals between the legume and the rhizobia. Therefore, a particular rhizobia species nodulates a particular group of related legume species.

Another strength is our use of LC-MS/MS for the T assays LC-MS/M

Another strength is our use of LC-MS/MS for the T assays. LC-MS/MS is considered selleck screening library the ‘gold standard’

against which all assays are compared. Previous studies of T in HIV-infected patients have used radioimmunoassay; however, LC-MS/MS ensures the accuracy and credibility of T measurements in this population. Most of the HIV-infected participants were on HAART, however, so results are not generalizable to antiretroviral-naïve individuals. Furthermore, it is difficult to determine the effect of antiretroviral therapy compared with the direct effects of HIV. Our ability to determine temporality is limited by the cross-sectional design of the study. Additionally, the timing of the collection of blood samples was not standardized, and therefore we cannot accurately assess

the true gonadal state of each participant. In a supplementary analysis, we examined the preclinical CVD outcomes for samples drawn in the morning only and in the evening only separately, and found no association between T and CAC or IMT/carotid lesions when data were stratified by time of blood collection, similar to when all samples were analysed together. Finally, the HIV-infected and HIV-uninfected patients had differences in their traditional CVD risk factors (hypertension, hyperlipidaemia, and smoking status), which we adjusted for in multivariate analysis. To our knowledge, this is the first examination of the association find more between FT and CAC presence, carotid IMT, and carotid lesion presence in men with and at risk for HIV infection. We found that, despite lower FT levels and a higher prevalence of carotid Acetophenone lesions, FT was not associated with any of the measures of subclinical CVD. However, CVD is of increasing concern in an aging population with HIV infection. Additional research should be conducted to determine if all HIV-infected men should be screened for

hypogonadism and whether treatment decreases CVD risk. This work was supported by the National Institute of Allergy and Infectious Diseases, with additional supplemental funding from the National Cancer Institute and the National Heart, Lung and Blood Institute [MACS is supported by UO1-AI-35042, UL1-RR025005, UO1-AI-35043, UO1-AI-35039, UO1-AI-35040, UO1-AI-35041, R03-DA-026038 and M01 RR00425 (GCRC)]. Additional support was provided by the National Institutes of Health (National Center for Complementary and Alternative Medicine) (5K23AT2862 to T.T.B). The Multicenter AIDS Cohort Study (MACS) includes the following. Baltimore: The Johns Hopkins University Bloomberg School of Public Health: Joseph B. Margolick (Principal Investigator), Michael Plankey (Co-Principal Investigator), Barbara Crain, Adrian Dobs, Homayoon Farzadegan, Joel Gallant, Lisette Johnson-Hill, Ned Sacktor, Ola Selnes, James Shepard and Chloe Thio.

Until pBBR1RInt was cured, cells were subcultured in LB broth at

Until pBBR1RInt was cured, cells were subcultured in LB broth at 30 °C overnight in the absence of kanamycin. Cell growth was monitored by measuring the OD600 nm using an Ultrospec

3000 spectrophotometer (Pharmacia Biotech., Uppsala, Sweden). Cell concentration, defined as gram DCW per liter of culture broth, was determined by weighing dry cells as described previously (Choi et al., 2002). The relationship between the OD600 nm and the cell concentration (1 OD600 nm=0.448 g DCW L−1) was calculated from the predetermined standard curve relating the OD600 nm to DCW. The content and monomer composition of the synthesized polymer were determined by GC as described previously (Braunegg et Veliparib solubility dmso al., 1978). Liquid cultures were centrifuged at 4000 g for 20 min, and then the cells were washed twice with distilled water and dried overnight at 100 °C. The dried cell pellet was subjected

to methanolysis with benzoic acid as an internal standard in the presence of 15% sulfuric acid (H2SO4). The resulting methyl esters of constituent 3-hydroxybutyrate were assayed by GC according to the method of previous report (Braunegg et al., 1978). GC analysis was performed by injecting 1 μL of sample into an Agilent 6890N GC system (Agilent Technologies, Palo Alto, CA) equipped with an Agilent Idelalisib ic50 7683 automatic injector, a flame ionization detector, and a fused silica capillary column (ATTM-Wax, 30 m, ID 0.53 mm, film thickness 1.20 mm, Alltech, Deerfield, IL). The GC oven temperature was initially maintained at 80 °C for 5 min and ramped to 230 °C at 7.5 °C min−1, and then it was increased with a gradient 10 °C min−1 until 260 °C and held for 5 min. Helium was used as a carrier gas. The injector and detector were maintained at 250 and 300 °C, respectively. The PHB content (wt%) was defined as the percentage of PHB concentration (g L−1) to cell concentration (g L−1). The concentrations of d-fructose and organic acids were determined BCKDHA by

HPLC (Varian ProStar 210, Palo Alto, CA) equipped with UV/VIS (Varian ProStar 320) and RI (Shodex RI-71, Tokyo, Japan) detectors. A MetaCarb 87H column (300 × 7.8 mm, Varian) was isocratically eluted with 0.01 N H2SO4 at 60 °C and at a flow rate of 0.6 mL min−1. To develop a gene knockout system in R. eutropha, the mobile group II intron system was used. The polyhydroxyalkanoate synthase gene, phaC1, was selected as a target gene to be deleted as a demonstration of the knockout system. A broad-host-range vector pBBR1MCS2 was used as a backbone plasmid (Fig. 1; Kovach et al., 1995). To clone the retargeted intron into the donor plasmid at the BsrGI and HindIII sites, the HindIII site present in the backbone plasmid, pBBR1MCS2, must first be removed.

, 1995) Psuedomonas aeruginosa is an opportunistic pathogen that

, 1995). Psuedomonas aeruginosa is an opportunistic pathogen that accounts for a considerable portion of hospital-acquired infections and is also a common source of infection for sufferers of cystic fibrosis (CF). Psuedomonas aeruginosa uses two HL signaling systems, which combined regulate over 300 genes (Schuster & Peter Greenberg, 2006), many of which are implicated in virulence factor production. HL signaling results in extensive changes in gene expression affecting secondary metabolism,

sporulation, the elaboration of virulence factors and the formation of biofilms (Schuster & Peter Greenberg, 2006). Because HL concentration in the extracellular medium increases with population density, the system allows bacteria to coordinate population-wide gene expression simultaneously. Studies have Seliciclib shown that another related HL produced by P. aeruginosa was able to abrogate Candida albicans filamentation (Hogan & Kolter, 2002; Hogan et al., 2004), a virulence trait. This study provides a striking example of competitive exclusion because restricting the ability of C. albicans to transition between morphotypes

(an important virulence trait) presumably gives P. aeruginosa a competitive advantage. HLs play a central role in regulating and coordinating infection. As a result, considerable research has been directed at identifying inhibitor HL systems. For example, a tetrazole with a 12C alkyl tail (Muh et al., 2006) was recently identified as an effective inhibitor (IC50=30 nM) of P. aeruginosa. Importantly, this molecule may not interfere with the growth of P. C646 cell line aeruginosa. This means that while highly effective

at disrupting the machinery used to coordinate infection, the compound does not create a strong selective pressure to develop resistance unlike current therapeutics. This is another emerging common theme among chemical inhibitors of small-molecule signals. Vibrio cholerae is the etiological agent of the debilitating human disease cholera. While V. cholerae uses the autoinducer-2 (AI-2, described in Aspartate more detail later in the review) like many other bacterial species, in addition, it also uses a unique autoinducer, cholerae autoinducer 1 (CAI-1), an α-hydroxyketone. CAI-1 serves to terminate host colonization, halting biofilm formation and virulence factor expression (Higgins et al., 2007). This observation is consistent with V. cholerae’s transmission route, where bacteria leave the host simultaneously during the onset of the diarrhea that characterizes the illness. Thus, host colonization and biofilm formation continue until the population reaches a sufficient density, at which point the bacteria reverse the colonization process to spread to other hosts. Exploiting the small-molecule signaling involved in V. cholerae infection is quite simple, as introducing high concentrations of the HL autoinducer will terminate host colonization, thus ending the infection.

There were no discontinuations because

There were no discontinuations because Casein Kinase inhibitor of nervous system events in the etravirine group (vs. 0.5% in the placebo group) and a very low frequency of discontinuations because of psychiatric events in both the etravirine and placebo treatment groups (0.3% and 0.2%, respectively). The frequency of grade 3 or 4 nervous system AEs of interest was low and comparable between the treatment groups, and similar proportions of patients reported grade 3 or 4 psychiatric events of interest (Table 1). By preferred term, and regardless of severity or causality, the most common nervous system events

of interest were headache, dizziness and somnolence, and the most common psychiatric events of interest were depression, insomnia and anxiety, each of which occurred in the etravirine

group at a rate similar to that in the placebo group (Table 1). Most neuropsychiatric events of interest occurred early during treatment (Fig. 1). A previous history of psychiatric disorders was found to increase the occurrence of nervous see more system and psychiatric AEs of interest in both treatment groups (P < 0.0001 and 0.0728 in the etravirine and placebo groups, respectively). Of those patients with a psychiatric history [46.7% (n = 280) and 43.9% (n = 265) in the etravirine and placebo groups, respectively], the overall frequency of neuropsychiatric events of interest was 42.1% and 40.0% in the etravirine and placebo groups, respectively; in patients with no psychiatric history, the corresponding frequencies were 26.3% and 32.7%, respectively. Regardless of severity or causality and consistent with previous findings at weeks 24 and 48, rash occurred at a significantly higher frequency

in the etravirine arm than in the placebo arm (20.5% vs. 11.8%, respectively; 95% CI 4.6–12.9; P < 0.0001, Fisher's exact test; predefined analysis) (Table 2). Most cases of rash occurred within the first 2 weeks of treatment and resolved with continued treatment; the frequency of rash occurring after 48 weeks was low. Discontinuation PAK5 because of rash was infrequent in the etravirine group (2.2%, all of which occurred in the first 48 weeks of treatment) and there were no discontinuations because of rash in the placebo group. The majority of rash events were grade 1 or 2 in severity (Table 2). One patient in the placebo group developed a grade 4 vesicular rash in the first 48 weeks (Stevens–Johnson syndrome), thought to be related to an allergic reaction to trimethoprim/sulfamethoxazole; no other grade 4 rashes were reported. There were no clear differences between the treatment groups for different individual types of rash apart from general rash (Table 2). A significantly higher proportion of women than men in the etravirine group reported rash [31.7% (n = 19) vs. 19.3% (n = 104), respectively; P = 0.

The resulting cDNA was used to amplify the gene Rv2145c (wag31Mtb

The resulting cDNA was used to amplify the gene Rv2145c (wag31Mtb) by PCR using the primers 5′-CTGGTTGCGTTCATCGGTAT-3′ and 5′-GAAAACTGGCGCGTGTCC-3′. The cDNA from the dnaJ1 genes was amplified as a control using the primers 5′-ARICCICCCAAIARRTCICC-3′ and 5′-CGIGARTGGGTYGARAARG-3′ (Yamada-Noda et al., 2007). All PCR reactions were performed under the following conditions: one cycle of 94 °C (2 min); 35 repeating cycles of 94 °C (30 s), 54 °C (30 s), and 72 °C (60 s); and a final cycle

of 72 °C (7 min). PCR products were analyzed by 1% agarose gels and ethidium bromide staining. Formvar carbon-coated nickel grids were used to lift individual M. smegmatis cells from 7H10 agar plates, which were selleck chemicals llc then stained with 2% phosphotungstic acid, as described previously (Arora et al., 2008). Samples were viewed using a Joel TEM 1200 EX electron microscope (Joel USA Inc., Peabody, MA), and images were captured using a Mega View III camera (Lakewood, CO). The results of assays for liquid-culture turbidity are expressed as means ± SDs from three independent experiments. Student’s t-test was used to assess differences PCI32765 between various groups with a level of significance set at 0.005. Previous studies have shown that RelMtb is involved in the regulation of more than 150 genes in M. tuberculosis,

including virulence factors and antigens (Dahl et al., 2003). In order to identify some of these antigens potentially regulated by RelMtb, lysates of H37Rv, H37RvΔrelMtb, and the complemented mutant strain H37RvΔrelMtbattB∷relMtb were compared using polyclonal antibodies raised against the wild-type H37Rv strain (Fig. 1a). Western blot analysis was conducted on bacterial medroxyprogesterone whole-cell lysates of M. tuberculosis strains grown to the late stationary phase (OD600 nm 2.8). Previous studies have shown that cells in this stage of bacterial growth are activated for the stringent response (Primm et al., 2000; Dahl et al., 2003, 2005). One protein band was observed with a 4.5-fold reduction in expression level

in the H37RvΔrelMtb strain, and this protein is approximately 45 kDa in size (Fig. 1a; arrow). A protein band at this position was visualized in the corresponding Coomassie brilliant blue-stained polyacrylamide gels of H37Rv protein lysates (data not shown) and was excised, destained, and subjected to trypsin digestion and analysis by matrix-assisted laser desorption. The 45-kDa protein was identified as the M. tuberculosis Rv2145c gene product Wag31Mtb (Cole et al., 1998). In M. tuberculosis, this protein is also known as DivIVA (Kang et al., 2005) and antigen 84 (Hermans et al., 1995), and it is an ortholog of MinE in E. coli (Hu et al., 2003). Previous microarray comparisons reveal that wag31Mtb is expressed 2.6-fold higher in cells that have an intact rel gene and are starved for nutrients (Dahl et al., 2003). This Western blot analysis is Fig. 1a confirms this rel-dependent expression of wag31Mtb.

American Type Culture Collection (ATCC), food and clinical isolat

American Type Culture Collection (ATCC), food and clinical isolates, of

Gram-negative bacteria (Escherichia coli, Pseudomonas aeruginosa, Pseudomonas mirabilis), Gram-positive bacteria (Listeria monocytogenes, Enterococcus hirae, Enterococcus faecium, Bacillus subtilis, Staphylococcus epidermidis, Staphylococcus aureus), the yeasts Candida albicans and Candida parapsilosis and the fungus Aspergillus niger were used. Pistachio extracts were active against Gram-positive bacteria with a bactericidal effect observed against L. monocytogenes (ATCC strains and food isolates), S. aureus and MRSA clinical find more isolates. Extracts from raw shelled pistachios were more active than those from roasted salted pistachios. The bactericidal activity of pistachio extracts could be used to help control the growth of some microorganisms in foods to improve safety and may find application as a topical treatment for S. aureus. “
“Infections with non-typhoidal Salmonella strains are constant and are a non-negligible Selleckchem Roxadustat threat to the human population. In the last two decades, salmonellosis outbreaks have increasingly been associated with infected fruits and vegetables. For a long time,

Salmonellae were assumed to survive on plants after a more or less accidental infection. However, this notion has recently been challenged. Studies on the infection mechanism in vegetal hosts, as well as on plant immune systems, revealed an active infection process check details resembling in certain features the infection in animals. On one hand, Salmonella requires the type III secretion systems to effectively infect

plants and to suppress their resistance mechanisms. On the other hand, plants recognize these bacteria and react to the infection with an induced defense mechanism similar to the reaction to other plant pathogens. In this review, we present the newest reports on the interaction between Salmonellae and plants. We discuss the possible ways used by these bacteria to infect plants as well as the plant responses to the infection. The recent findings indicate that plants play a central role in the dissemination of Salmonella within the ecosystem. “
“Although DNA is the ultimate repository of biological information, deployment of its instructions is constrained by the metabolic and physiological status of the cell. To this end, bacteria have evolved intricate devices that connect exogenous signals (e.g. nutrients, physicochemical conditions) with endogenous conditions (metabolic fluxes, biochemical networks) that coordinately influence expression or performance of a large number of cellular functions. The phosphoenolpyruvate:carbohydrate-phosphotransferase system (PTS) is a bacterial multi-protein phosphorylation chain which computes extracellular (e.g. sugars) and intracellular (e.g. phosphoenolpyruvate, nitrogen) signals and translates them into post-translational regulation of target activities through protein-protein interactions.

53/100 person-years), though similar to rates reported among
<

53/100 person-years), though similar to rates reported among

HIV/HCV-coinfected persons in other studies (2.63/100 person-years) [27]. Indeed, ESLD has emerged as the primary cause of death among cohort participants. There is mounting and consistent evidence that successful treatment for HCV infection is the most effective means of preventing liver-related outcomes in coinfection [28]. Despite this, uptake of HCV treatment was low, with 70% of the cohort remaining untreated. While low, this treatment rate is consistent with those reported in the literature [29, 30]. Numerous barriers to accessing HCV treatment have been described, including active drug use, poor adherence, and psychiatric and other ZD1839 molecular weight medical comorbidities Selumetinib in vivo [31], all of which were present at high levels among cohort participants. Furthermore, HCV treatment itself is complex and associated with a number of important toxicities that limit its acceptance and impact successful treatment completion [32]. Finally, we observed very high rates mortality, particularly secondary to ESLD and drug overdose. Indeed, over 50% of deaths observed were attributable to these potentially preventable causes. Standardized mortality rates were particularly high among women, who were nearly 30

times more likely to die than Canadian women of the same age in the general population. In part this may be attributable to lower death rates among young and middle-aged women in the general population compared with men. Other potential reasons may include the over-representation of aboriginals about and high levels of current IDU among women enrolled in the cohort. Although small numbers and the lack of standardized data available for aboriginals precluded obtaining standardized mortality ratios adjusted for ethnicity, it is notable that the death

rates and standardized mortality ratios we observed for the coinfected population also far exceed reported age-adjusted death rates among aboriginals and Metis in Canada (e.g. standardized mortality ratios of 1.38 for men and 1.72 for women, for 1999–2001) [33]. Overall, mortality rates were high even when compared with other similar populations. For example, among HIV-infected patients starting ART in 13 cohorts in Europe, the USA and Canada, the overall crude death rate was 0.95/100 person-years with a standardized mortality ratio of 3.36 (95% CI 3.16–3.56) [34]. In the subgroup of IDUs, mortality was higher, at 1.95/100 person-years, although still almost two-fold lower than what we observed. There is clearly an urgent need to address these potentially preventable causes of morbidity and mortality.

Conserved hypothetic proteins were aligned to pfam database for p

Conserved hypothetic proteins were aligned to pfam database for putative functions. In the initial experiments, we observed that the biofilm formation of S. aureus NCTC8325, which is rsbU defective, on a polystyrene or a glass surface was obviously inhibited in dithiothreitol-supplemented TSB. We postulated that the sulfhydryl group may play a role in biofilm inhibition. GSK126 purchase As expected, replacing dithiothreitol with BME or cysteine led to a similar phenomenon (Fig. 1a). The minimal biofilm-inhibitive concentrations of dithiothreitol, BME and cysteine were determined later by static biofilm formation assays on 96-well microtiter plates. The amount of the biofilms formed decreased gradually as the concentrations

of the supplemented sulfhydryl compounds increased. For S. aureus NCTC8325 cells, 5 mM dithiothreitol, 10 mM cysteine or 20 mM BME reduced over 70% biofilm formation on the polystyrene surface (Fig. 1b). To verify whether the Ceritinib manufacturer phenomenon is strain specific, the biofilm-forming abilities of several S. aureus strains and one S. epidermidis strain were tested in the presence of sulfhydryl compounds (Fig. 2). All three tested sulfhydryl compounds, including dithiothreitol, BME and cysteine, reduced biofilm formation in these staphylococcal strains, although the susceptibility varied among the different strains. To explore whether sulfhydryl compound

would cause a growth inhibition on S. aureus, we determined the growth curves of S. aureus NCTC8325 cells in TSB, TSB supplemented with 10 mM dithiothreitol, TSB supplemented with 20 mM cysteine and TSB supplemented with 40 mM BME by measuring OD600 nm at different time points. No significant difference in the growth rate among the samples was observed (Fig. S1). The result indicated that the biofilm inhibition caused by thiols probably involved the switch of bacterial physiological states rather than Endonuclease the inhibition of bacterial growth. The first step in the formation of an S. aureus biofilm is adhering to the matrix surface. We investigated

the primary attachment ability of S. aureus NCTC8325 cells on 24-well polystyrene plates with or without the presence of thiols. However, no difference was observed in the primary attachment abilities of the bacterial cells in the control group and the sulfhydryl compound addition groups (Fig. 3). The production of PIA is a major event for biofilm maturation in S. aureus. The transcriptional level of icaADBC was investigated to find whether PIA synthesis was affected after treatment with thiols. Real-time reverse transcriptase-PCR showed that the mRNA levels of ica in the bacterial cells pretreated with 5 mM dithiothreitol, 10 mM cysteine or 20 mM BME for 30 min were significantly decreased compared with the control (Fig. 4a). In addition, extracellular PIA was also measured by the Elson–Morgan assay. An icaADBC deletion mutant of NCTC8325 was used as the negative control.

For CLSM, a Leica TCS SP5 system, equipped with a × 63 apochromat

For CLSM, a Leica TCS SP5 system, equipped with a × 63 apochromatic objective (NA=1.4) was used. Both green fluorescent protein (GFP) and PI were excited at 488 nm using an argon laser. GFP AG-014699 in vivo fluorescence signal was collected between 500 and 540 nm, and PI between 610 and 660 nm. Cytox Orange was excited at 543 nm using a helium–neon laser, and its emission light was collected between 545 and 615 nm. Image stacks were analyzed using the computer program comstat (Heydorn et al., 2002) and values for biovolume and average biofilm thickness were recorded. Optical sections were created using the imaris image processing software (Bitplane, Zürich, Switzerland).

To obtain eDNA, culture samples were treated with 10 U mL−1 cellulase at 37 °C for 1 h, followed by treatment with 10 U mL−1 proteinase K for another 1 h (Wu & Xi, 2009). Treated samples were centrifuged at 10 000 g for 10 min and the resulting supernatant was amended with 0.25 M NaCl, followed by precipitation

CFTR activator in 2 × 95–100% ethanol. The precipitate was collected by centrifuging at 10 000 g for 10 min and then washed twice with 95–100% ethanol. The purified precipitate was dissolved in TE buffer. Cellular DNA was extracted by first placing the samples in boiling water for 10 min and then at −80 °C for 10 min. The process was repeated and then the sample was centrifuged at 10 000 g for 10 min, and the supernatant was collected. RAPD analysis was performed as described previously (Verma et al., 2007) using two different oligonucleotide primers (OPB07, 5′-GGGTAACGCC and OPA09, 5′-GGTGACGCAG). Each

25-μL reaction contained 45 ng template DNA, 40 pmol of oligonucleotide primers, 1 U Taq DNA polymerase, 1 × PCR buffer, 200 μM each dNTP, and 2.5 mM MgCl2. Amplification was performed by denaturation at 94 °C for 3 min, followed by 40 cycles at 94 °C for 1 min, 37 °C for 1 min, 72 °C for 2 min, and a final Molecular motor extension at 72 °C for 10 min. The RAPD products were analyzed by gel electrophoresis in a 2% agarose gel. Fragment sizes were determined by comparison with a standard curve obtained by plotting known ladder fragment size against the distance from the loading well to the center of each band, where log (fragment size)=−0.0258 × distance+4.1714, R2=0.9385). Particulate protein contents of the cultures were measured using the QuantiPro™ BCA Assay Kit (Sigma). Cultures were subject to EPS extraction after Frølund’s method (Frølund et al., 1996), by adding 10 g of cation-exchange resin (AB-washed Dowex Marathon, Sigma 91973) to each culture, intense stirring (300 r.p.m.) overnight at 4 °C, and centrifugation at 5000 g for 20 min. The supernatants were stored at 4 °C before further analysis. Carbohydrates were quantified by the phenol–sulfuric acid method (Dubois et al.