Towards a more complete genetic mapping of the secondary metabolism in A. nidulans, we first cultivated a reference strain on an array of different growth media to uncover polyketides that were not previously linked to a gene cluster. This analysis revealed several compounds, including austinols, violaceols, arugosins and prenylated xanthones. Next, genetic links to these compounds were established by constructing and screening an A. nidulans mutant library

containing individual deletions of 32 putative PKS genes. The A. nidulans strain IBT29539 (argB2, pyrG89, veA1, nkuAΔ) (Nielsen et al., 2008) was used as the reference strain and for deletion-strain constructions. Escherichia coli strain DH5α was used for cloning. Fungal minimal selleck inhibitor medium (MM) was as described in Cove (1966), but with 1% glucose, 10 mM NaNO3 and 2% agar. Medium

for alcA promoter induction consisted of MM supplemented with 100 mM l-threonine and 100 mM glycerol as carbon source instead of 1% glucose. Polyketide screening media variants CYA, CYAs, YES and RT were prepared as per Frisvad & Samson (2004). CY20 medium consisted of CYA with 170 g sucrose; RTO contained RT with 30 g organic oat meal; and YE was made as YES but without sucrose. All media variants were supplemented with 10 mM uridine, 10 mM uracil and/or 4 mM l-arginine where appropriate. Individual PKS gene deletions were carried out as described previously (Nielsen et al., 2006), except that PARP inhibitor the targeting fragments were assembled using Gateway technology (Hartley et al., 2000) (see Table S1 for PCR oligonucleotide and Fig. S2 for an overview of the procedure). The A. nidulans transformants were streak

purified and rigorously screened through three complementing diagnostic PCRs. Subsequently, the Aspergillus fumigatus pyrG marker was eliminated from all strains by selecting on 5-fluoroorotic acid medium before final verification by two additional complementing Gemcitabine cost diagnostic PCRs (see Fig. S3 and Table S2). All strains have been deposited in the IBT strain collection, DTU, (http://www.fbd.dtu.dk/straincollection/). The amino acid substitution of serine to alanine, S1660A, in ausA (AN8383) was created by USER fusion (Geu-Flores et al., 2007) according to the method described by Hansen et al. (2011). The allele was transferred to IBT29539 and the pyrG marker was eliminated by direct repeat recombination, creating strain IBT31032 containing only the desired point mutation. The strain was verified to contain the ausA-S1660A allele by sequencing (StarSEQ, Germany). See Table S3 for primer details. The gene, ausA, was PCR amplified by USER fusion (Geu-Flores et al., 2007) and inserted into both pU1111-1 and pU1211-1 (Hansen et al., 2011) creating pDH23 (gpdA promoter) and pDH24 (alcA promoter), respectively.

During February 25 to April 14, 14 additional rash illness cases were detected only among crew members: one through medical record review and 13 through passive surveillance in the ship’s infirmary (Figure 1). During the onboard medical log review, a case of probable varicella was identified in a 23-year-old Filipino crew member, who boarded the ship to work in food services, and 22 days find more later was diagnosed with varicella

in the ship’s infirmary. Thirteen crew members visited the infirmary with a rash illness. Of these, two met the case definition for confirmed measles (one by serology, and one by clinical diagnosis by the ship’s physician and epidemiologic link to the confirmed case); ten met the Council of State and Territorial Epidemiologists case definition for varicella[8] (six were confirmed by clinical characteristics and an epidemiologic link, and the remaining four were probable cases by clinical diagnosis only); and one case of rash illness remained undiagnosed and did not have laboratory evidence of acute rubella or measles and did not meet the case definition for measles, rubella, or varicella (Figure 1). The two additional cases of measles were among crew members employed in food services or entertainment;

the additional varicella cases occurred among crew members from various shipboard occupations (ie, food services, galley, housekeeping, engineering, and entertainment). All these cases were among crew members who had been aboard the ship for at least one incubation period of either measles or varicella. Of 1,197 crew members evaluated for proof of buy Pifithrin-�� immunity, 3 had proof of immunity to measles and rubella based on vaccination records. During pre-immunization counseling, three crew members were found to be pregnant; of those, one had serological evidence of immunity to rubella and measles and two were susceptible PIK-5 and disembarked for clinical monitoring because of their exposure to rubella.

The remaining 1,191 crew members received the MMR vaccine after giving informed consent. The MMR vaccine was supplied by BCHD (with cost reimbursement from the cruise line), whose nursing staff performed counseling and administration of the vaccine. Close contacts of varicella cases were defined as those having ≥ 5 minutes of face-to-face contact with the case during the infectious period (1–2 d before rash onset until lesions crust or 6 d after rash onset).[9] Contacts meeting this definition were identified only among crew members (eg, crew roommate and workmates) and those who were susceptible[9] were monitored for onset of fever or rash for 21 days after their last exposure to a varicella case. To suspend continued varicella transmission, with the detection of third generation cases, the cruise line also offered the varicella vaccine to susceptible contacts.

, 2005). In contrast to the PhoQ sensors from Enterobacteriaceae, the P. aeruginosa PhoQ protein lacks the AMP-binding domain and only responds to limiting concentrations of divalent cations (Prost et al., 2008). In agreement, a recent study suggested that ParS, which is part of the ParRS two-component system, might be the P. aeruginosa AMP sensor (Fernandez et al., 2010). Recently, various AMPs, including polymyxin B, were shown to activate the S. Typhimurium RcsBCD phosphorelay system JQ1 molecular weight through the OM lipoprotein RcsF

(Farris et al., 2010). AMP-mediated disruption of OM integrity is likely sensed by the lipoprotein RcsF located in the inner leaflet of the OM leading to RcsBCD activation through a mechanism that remains unclear. The Rcs phosphorelay contributes to AMP resistance by promoting the expression of capsule genes and production of colanic acid, which is a precursor of 4-amino-4-deoxy-l-Arabinose (l-Ara4N), the sugar responsible for polymyxin B resistance upon addition to the 4′ phosphate of lipid A. Inactive AMP precursors are processed into active AMPs by host proteases. Active AMPs can be degraded into

selleckchem inactive fragments by bacterial proteases that are either secreted or localized at the OM. In a pioneer study, Schmidtchen et al. (2002) reported the P. aeruginosa elastase and a protease from Proteus Etomidate mirabilis, both isolated from culture supernatants,

inactivated LL-37. The P. mirabilis protease was later identified as the ZapA zinc-metalloprotease and confirmed to cleave human LL-37 and β-defensin 1, but not β-defensin 2 (Belas et al., 2004). Although these proteases usually have broad-spectrum activity against various proteins or peptides, strict substrate specificity can be observed. For example, the ZmpA and ZmpB zinc-metalloproteases from Burkholderia cenocepacia cleaved LL-37 and β-defensin 1, respectively (Kooi & Sokol, 2009). A number of proteases secreted by bacteria in the oral cavity have also been implicated in AMP resistance. For example, Porphyromonas gingivalis, which is the pathogen most associated with chronic periodontal disease, is highly proteolytic and secretes three proteases known as gingipains that belong to the cysteine family of proteases and cleave substrates after arginine and lysine residues. Degradation and inactivation of LL-37 and β-defensin 3 by gingipains was reported (Gutner et al., 2009; Maisetta et al., 2011). Many Gram-negative pathogens, mainly of the Enterobacteriaceae family, rely on proteases found at the OM to inactivate AMPs. These proteases, exemplified by E. coli OmpT, belong to the omptin family (Hritonenko & Stathopoulos, 2007). Omptins share high amino acid sequence identity (45–80%) and adopt a conserved β-barrel fold with the active site facing the extracellular environment.

The amplification of such a diverse set of bacterial strains with identical primer pairs underscores the general applicability of this primer set for the molecular taxonomy of this bacterial group. Given that the amplified strains belong to different clades of Streptococcus, these primers might also be useful for taxonomic study in neighboring taxa. Levels of similarity were much lower for the rpoA than 16S rRNA gene sequences (Table 2). A pairwise comparison of rpoA sequences between the strains revealed similarity values between 82.2% and 100%, compared with 93.3–100% between the 16S rRNA gene sequences, indicating a high discriminatory potential

for rpoA. At the intraspecies level, the levels of similarity ranged from 92.3% to 99.3% for rpoA, and 96.8% to 100% for the 16S rRNA gene. The S. pneumoniae, S. Talazoparib purchase oralis, and S. mitis strains were well differentiated by rpoA sequence analysis. Compared with the other reference strains, Staphylococcus intermedius KCTC 3268T and Streptococcus

anginosus ATCC 33397T, S. pneumoniae, S. oralis, and S. mitis strains showed significantly less similarity in rpoA (82.2–84.9%) than in the 16S rRNA gene RO4929097 nmr (95.2–95.9%). A phylogenetic tree reflecting the rpoA and 16S rRNA gene sequences is shown in Fig. 1. The rpoA-based tree generated longer branches compared with 16S rRNA gene phylogeny, implying that rpoA has evolved at a higher rate than the 16S rRNA gene. In the rpoA tree, the S. pneumoniae, S. mitis, and S. oralis strains formed distinct branches and were placed in a separate cluster that clearly differentiated each species group, supported by a high bootstrap value. By contrast, S. pneumoniae, S. mitis, and S. oralis species were not placed in a distinct cluster on the 16S rRNA gene-based tree, and it could not discriminate each species. At the intraspecies level, S. oralis strains ATCC 9811, ATCC 700233, DSMZ 20066,

KCOM 1401, Dapagliflozin KCOM 1414, KCOM 1416, KCOM 1407, and KCOM 1408 showed a much closer relationship with the S. pneumoniae strains than S. oralis type strain KCTC 13048T. In addition, S. pneumoniae strain CCARM 4033 was placed in the S. mitis cluster. Staphylococcus intermedius KCTC 3268T and S. anginosus ATCC 33397T were more distant from the S. pneumoniae, S. mitis, and S. oralis strains in both rpoA and 16S rRNA gene trees. The comparison of 16S rRNA gene sequences is a particularly powerful tool for bacterial taxonomy (Goodfellow et al., 1999). The 16S rRNA gene evolves so slowly, however, that phylogenetic information based on this molecule may not always be sufficient to distinguish closely related species or to resolve their evolutionary relationships (Dahllof et al., 2000). In addition, when several copies of the 16S rRNA gene are present, sequence heterogeneity results in ambiguities in the sequence chromatograms derived from direct sequencing of the PCR products.

In this cross-sectional

survey carried out in Italy from November 2010 to February 2011, more than 40% of interviewed women living with HIV reported at least one induced abortion in her reproductive health history. This unexpectedly high prevalence might be driven by the fact that the median age of the women included in the study was > 40 years and that nearly 20% had a history of drug abuse, which is known to be a factor associated with abortion in the general population Apitolisib clinical trial [13-16]. Another reason for our finding may be that our study was based on self-report and not chart review or cohort data. The fact that women of all ages were interviewed at their routine visit at the HIV care centre

and not when accessing a specific health care service [such as gynaecology or sexually transmitted diseases (STD)] or at a specific time-point may have increased detection rates. In most cases abortion occurred before HIV diagnosis, suggesting that women diagnosed with HIV infection often have a sexual health history that includes multiple, complex and traumatic events. www.selleckchem.com/products/PF-2341066.html In our study, the high proportion of abortions before HIV diagnosis may also be a result of the fact that women participating in the DIDI study generally received their HIV diagnosis at an advanced stage of disease, with a CD4 count nadir of approximately 200 cell/μL, in their late twenties or thirties. After specific Italian abortion legislation was enacted in 1978, rates of abortion among the general Italian female population first rose and

then declined steadily, from a peak of 16.9 abortions per 1000 women of reproductive age in 1983, to 9.7 in 1996, to 9.6 in 2005 and 8.3 in 2009 [17]. In our study, the rate observed in women not yet diagnosed with HIV infection was 24.1 per 1000 PYFU before 1990 and declined to 19.6 and 14.0 per 1000 PYFU in 1990–1999 and 2000–2010, respectively. Thus, we can conclude that our multicentre population of HIV-positive women displayed a much higher risk of abortion even before the HIV diagnosis, compared with the general population in Italy. In particular, during the last 10 years, they have had a 50% increased risk [17]. This study identifies a need for more effective strategies why in the management of women who plan to have an abortion, with particular emphasis on HIV and other sexually transmitted diseases. This may be achieved by establishing routine HIV counselling and testing at the time of the abortion. To date in Italy, HIV and family planning services have been offered separately. From a public health point of view, a high induced abortion rate among HIV-infected and uninfected women is of particular concern, being the result of unprotected sexual intercourse, which carries the danger of HIV acquisition or transmission.

83 to 61.67 in comparison with the pathogen control. Root colonization analysis indicated that CS-20 clearly did not appear to influence the growth of cucumber seedlings. Quantitative reverse-transcriptase polymerase chain reaction (qRT-PCR) revealed that CS-20-mediated defence response was activated by

PR3, LOX1 and PAL1 and the pathogen-mediated resistance response was regulated by PR1 and PR3. Moreover, both nonpathogenic and pathogenic F. oxysporum were able to upregulate NPR1 expression. In contrast to a pathogen, CS-20 can activate the Ca2+/CaM signal transduction pathway, and the gene expression of both CsCam7 and CsCam12 increased significantly. The gene expression analysis indicated that CS-20 Dapagliflozin ic50 strongly enhanced the expression of PR3, LOX1, PAL1, NPR1, CsCam7 and CsCam12 after inoculation. Overall, the defence response induced by CS-20 can be controlled by multiple genes in the cucumber plant. “
“Streptococcusuberis is an important pathogen that has been implicated

in bovine mastitis but the virulence factors associated with pathogenesis are not well understood. The aim of this work was to examine 11 putative and known virulence-associated genes by PCR in 78 S. uberis click here strains isolated from infected animals in Argentina. Additionally, the distribution of virulence patterns over various herds was determined. Not all genes were present in the strains but all of the detected virulence-associated genes were present in combination. Forty-seven (60.3%) isolates carried seven to 10 virulence-associated genes. Further analysis revealed 58 virulence patterns. Different patterns were found within the same herd and among herds, demonstrating that strains with different virulence patterns were able to cause mastitis. Despite the large number of strains with different virulence patterns, strains

with identical patterns was found. Detection of virulence-associated genes in individual S. uberis strains isolated from infected animals revealed one to 10 virulence genes. This may indicate that other virulence factors could be involved. The present study reveals the occurrence and distribution of 11 virulence-associated genes among S. uberis isolates from bovine mastitis in various herds and contributes to a better understanding Idoxuridine of the pathogenicity of this bacterium. Mastitis is a worldwide disease of dairy cattle and is caused by a wide variety of organisms that affect milk quality and yield, resulting in major economic losses. These losses can be attributed to a reduction in milk production, the associated costs of treatment and the culling of persistently infected and repeatedly infected cows. Mastitis pathogens are commonly divided into those that show a contagious route of transmission and those that also frequently infect the udder from an environmental reservoir. Several streptococcal species are among the most frequently isolated as udder pathogens.

To observe the impact of N and P concentrations on utilization of iron by bioreporter Palr0397-luxAB, a series of and concentrations in Fraquil medium with three

Fe3+ concentrations were set to determine the response of luciferase activities to the concentrations of N and P. In Fraquil medium with 10 or 100 nM Fe3+, luciferase activity of bioreporter Palr0397-luxAB was enhanced with the increase in concentration and decreased slightly (remaining at a high level) with ranging from 100 to 900 μM (Fig. 3a); similarly, its luciferase activity increased significantly when increased from 0.1 to 1 μM and varied a little with further increase in concentration (Fig. 3b). In Fraquil medium with 1000 nM Fe3+, its luciferase activity increased slightly with the increased N and P concentrations. When the concentrations of N and selleck compound P were high enough (e.g. 100 μM and 10 μM in this study), further increases in N and P concentrations had little influence on the luciferase activity, showing that iron utilization might not be affected by the uptake of N and P in cells. The variation of N and P concentrations had no effect on luciferase activity of bioreporter in 1000 nM Fe3+ concentration condition, which also indicated that iron utilization was not directly related with the uptake of N and P in cells. Fur acts as a Ku-0059436 mouse transcriptional repressor of iron-regulated promoters by virtue

of its iron-dependent DNA-binding activity to regulate expression of several genes involved in iron homeostasis (Escolar Cyclin-dependent kinase 3 et al., 1999). At high concentrations, Co2+ and Mn2+ presumably

mimic Fe2+ (Bagg & Neilands, 1987; Hantke, 1987), and Zn2+ can also activate Fur in vitro (Bagg & Neilands, 1987). So these metals could possibly interfere with iron detection. In addition, other metals such as Cu2+ can compete with iron to chelate dissolved organic siderophores secreted by cells, thus decreasing iron availability (Nicolaisen et al., 2008). The concentrations of metals in lakes greatly varied and are easily affected by surrounding environments. Take the concentration ranges of Co2+, Zn2+, and Cu2+ in Wuhan City (China) for instance; they were 3.7–4.9, 13.1–181.2, and 18.4–83.8 nM in Donghu Lake located in a scenic area, were 7.8–17.6, 1.2–285.1, and 43.1–916.7 nM in Moshui Lake situated in an industrial area, and were 4.9–6.8, 0–0.9, and 58.4–67.7 nM in Houguan Lake in the suburbs (Yu et al., 2007). In an attempt to determine the influence of Co2+, Mn2+, Zn2+, and Cu2+ concentrations on iron bioavailability, luciferase activity of bioreporter Palr0397-luxAB at six concentrations of Co2+, Mn2+, Zn2+, and Cu2+ was, respectively, measured in Fraquil medium with three Fe3+ concentrations. The increase in Mn2+ concentration had no effect on luciferase activity of the bioreporter (Fig. 3d).

We can use the model structures to predict the roles that the mutations may play in NK function. As shown in Fig. 3b, many mutations were far away from the active http://www.selleckchem.com/products/BKM-120.html pocket, and two mutations (V150 and T224) were close to the active site. The hydrophobic pocket of the active site

was broadened as a result of all of the amino acid substitutions (Fig. 3c), which may lead to changes in the protein structure and the catalytic activity. In the current study, we investigated how to improve the fibrinolytic activity of NK using directed evolution to broaden its medical or commercial applications. In vitro molecular evolution strategies are the most efficient methods for creating proteins with improved or novel properties. We generated a library of NK variants by the shuffling of genes encoding subtilisin NAT (NK), BPN′ and Carlsberg. To screen large libraries, the NK variants were expressed in E. coli. BL21(DE3)pLysS using a prokaryotic signal peptide, PelB, for efficient secretion. NK variants were selected based on zone-forming activity on agar plates with skim milk or fibrin. A mutant NK showed

a 2.3-fold increase in fibrinolytic activities compared Alpelisib mouse to the wild-type NK from Bacillus natto. The further sequence and structural study of the mutant enzyme will offer some insight into the structure-function relationship of NK. The amino acid sequence alignment of the three parents and the mutant enzyme revealed that the catalytic triad and the substrate-binding site were conserved. Nine amino acid substitutions were derived from SB, and Racecadotril the rest from SB or SC. No new mutations were introduced into the mutant enzyme sequence (Fig. 3a). To understand the functions of the amino acid substitutions, the identified

mutations in the selected mutant was distributed throughout the model of the mutant structure based on the three-dimensional model of NK that was previously constructed by our lab (Zheng et al., 2005). The three-dimensional structure showed that the strictly conserved residues of the catalytic centre (D32, H64, S221) and the substrate-binding sites (S125, L126, G127) were positioned in the pocket, which comprised two α-helices and seven β-strands (Fig. 3b). However, in the current study, none of the mutations was located in those strictly conserved regions throughout the mutant. Most of the mutations were located in the surface regions and far away from the pocket, with the exception of the substitutions A150V and T224S (Fig. 3b), which were very close to the Ser221 in the catalytic centre of the enzyme. This change may not be involved in hydrogen bonding with other residues. However, the combination of this change with other substitutions may result in the formation of a larger active-site pocket to improve the catalytic efficiency (Fig. 3c).

04). Among the 50 infants who were reported not to have received any prophylaxis, seven died within one week of delivery (including five born between 22 and 26 weeks Veliparib supplier of

gestation). Of the 43 surviving infants, 17 (39.5%) were born to women who received no antenatal antiretroviral therapy, at least eight of whom had reportedly declined all treatment interventions. Among infants who received prophylaxis, use of triple PEP increased significantly from 9.2% (297 of 3243) in 2001–2004 to 13.0% (624 of 4807) in 2005–2008 (P<0.001) (information on type of prophylaxis was missing for 105 infants). Over half of infants (54.4%; 86 of 158) born to untreated women received triple PEP, with an increase from 43.2% (41 of 95) in 2001–2004 to 71.4% (45 of 63) in 2005–2008 (P=0.001). Use of triple PEP also increased among infants born to women who were viraemic despite taking HAART, from 12.9% (114 of 883) in 2001–2004 to 31.6% (344 of 1088) in 2005–2008 (P<0.001), and was 23.2% (458 of 1971) overall. In analyses restricted to infants who received either single- or triple-drug prophylaxis, triple PEP was more common in 2005–2008 and was positively associated with lack of maternal antenatal treatment, shorter duration of maternal treatment, maternal receipt of intrapartum treatment, detectable maternal viral load, Selleckchem Dactolisib CD4 count <200 cells/μL, emergency caesarean section or unplanned vaginal

delivery, and preterm delivery (<37 gestation weeks) (Table 2). These factors were all significantly associated with use of triple PEP in multivariable analysis adjusting for time period, type and duration of maternal antenatal antiretroviral therapy, intrapartum treatment, maternal viral load, maternal CD4 cell count, mode of delivery and gestational age. Since 2005, the BHIVA guidelines have recommended consideration of triple PEP for infants born to untreated mothers or women who remain viraemic despite HAART: between 2005 and 2008, a third of these infants (33.8%; 389 of 1151) received Dichloromethane dehalogenase triple PEP. In this group, use of triple PEP was more common when maternal diagnosis occurred

in the last two weeks of pregnancy [94.1% (32 of 34) vs. 32.5% (355 of 1093) for earlier diagnosis; P<0.001], when maternal viral load was ≥1000 copies/mL [44.8% (155 of 346) vs. 28.5% (215 of 755) for viral load 50–999 copies/mL; P<0.001] and when maternal CD4 count was <200 cells/μL [43.2% (67 of 155) vs. 31.1% (282 of 908) for ≥200 cells/μL; P=0.004]. Use of triple PEP was also more common in infants born preterm (<37 weeks gestation) [46.5% (93 of 200) vs. 31.4% (290 of 923) for term infants; P<0.001] or by unplanned vaginal delivery [51.9% (27 of 52) vs. 32.5% (197 of 606) for elective caesarean section; P<0.001]. Ninety-four infants born at <28 weeks of gestation were reported, and information on receipt of PEP was available for 81 of these infants. Five infants died within one week of delivery and did not receive prophylaxis (described above).

The differences in antibiotic susceptibility between pH 5.5 and 7.3 were especially noticeable for the biofilm cells of S. aureus KACC13236. However, the antibiotic resistance patterns of S. aureus CCARM 3080 were not significantly different between the biofilm cells at pH 5.5 and 7.3, showing

MIC values of 128 μg mL−1 to more than 256 μg mL−1. As shown in Table 5, the planktonic and biofilm cells of S. Typhimurium Trichostatin A mw CCARM 8009 were more likely to be resistant to most antibiotics when compared to S. aureus KACC13236. Similarly, the biofilm cells of S. Typhimurium were more resistant to antibiotics compared with the planktonic cells. According to the results of the susceptibility of selected foodborne pathogens, the strains of S. aureus KACC13236, S. aureus CCARM 3080, S. Typhimurium KCCM 40253, and S. Typhimurium CCARM 8009 were assigned to antibiotic-susceptible S. aureus (S. aureusS), multiple antibiotic-resistant S. aureus (S. aureusR), antibiotic-susceptible S. Typhimurium (S. TyphimuriumS), multiple antibiotic-resistant S. Typhimurium

(S. TyphimuriumR), respectively. The gene expression patterns were evaluated in the antibiotic-susceptible (S. aureusS and S. TyphimuriumS) and multiple antibiotic-resistant strains (S. aureusR and S. TyphimuriumR) anaerobically cultured in TSB adjusted to pH 5.5 and 7.3 during the planktonic-to-biofilm transition for 48 h at 37 °C (Figs 1 and 2). The relative expression of norB, norC, mdeA, sec, seg, sei, sel, sem, sen, and seo genes was observed in the planktonic and biofilm cells of S. aureusS and S. aureusR (Fig. 1). The norB and mdeA genes

SP600125 order were overexpressed at the planktonic cells of both Methamphetamine S. aureusS and S. aureusR grown in TSB at pH 5.5 after 48-h incubation (Fig. 1a). The relative expression level of norC gene was increased 2.8-fold in S. aureusS. The relative gene expression levels of sel and sem were increased 5.0- and 3.0-fold, respectively, in the planktonic cells of S. aureusR grown in TSB at pH 5.5. As shown in Fig. 1b, the relative gene expression of norC and mdeA was stabilized in the planktonic cells of both S. aureusS and S. aureusR grown in TSB at pH 7.3. The relative expression levels of norB, seg, and sei genes were increased 52.6-, 2.6-, and 5.9-fold, respectively, in the planktonic cells of S. aureusR grown in TSB at pH 7.3. Unlike the planktonic cells, all genes were stable in the biofilm cells of S. aureusR grown in TSB at pH 5.5 and pH 7.3, except for the sec gene in S. aureusR biofilm cells formed in TSB at pH 5.5 (Fig. 1c,d). The relative gene expression levels of norB and mdeA were increased 1.9- and 2.0-fold, respectively, in the biofilm cells of S. aureusS grown in TSB at pH 5.5 (Fig. 1c). The highest expression level (116.6-fold) was observed at the norB gene in the S. aureusR biofilm cells grown in TSB at pH 5.5. As shown in Fig. 1d, the norB, norC, and mdeA genes were stable in the biofilm cells of both S. aureusS and S. aureusR grown in TSB at pH 7.3.