As a control, three groups of six plants each were inoculated wit

As a control, three groups of six plants each were inoculated with either PBS or gomesin (50 μM) or used as sentinel (noninoculated). Thirty days after inoculation, tobacco plants were inspected for leaf lesions, a typical symptom developed in X. fastidiosa-infected tobacco plants. Results correspond to two independent experiments, resulting in

a total of 36 analyzed plants for each group. Cell viabilities of the bacterial suspensions used in the inoculations were assessed by plating a sample on 2% agar PW broth medium following incubation at 28 °C for 7 days. Differences between groups were analyzed using Students’s t-test and considered statistically significant if the P-value was <0.05. It has been shown that gomesin is an AMP that presents strong activity against a huge number of microorganisms (Silva et al.,

2000) disrupting CX-5461 concentration the microbial membrane (Miranda et al., 2009). We have LEE011 datasheet verified that gomesin is effective against X. fastidiosa 9a5c, a virulent strain against citrus plants (Li et al., 1999). The MBC of gomesin was determined by viability assays to be 4.5–9 μg mL−1, which corresponds to 200–400 μM (Table 1). Both the virulent strain 9a5c and the avirulent strain J1a12 (Koide et al., 2004) exhibited identical susceptibility to gomesin and to conventional antibiotics ampicillin, tetracycline and streptomycin, suggesting that the avirulent phenotype of the strain J1a12 is probably

not due to a lower resistance to antimicrobial agents, eventually encountered in the plant host or the insect vector. To evaluate the gene expression profile upon exposure to a sublethal concentration of AMP, the virulent strain 9a5c of X. fastidiosa was treated Dichloromethane dehalogenase for 60 min with 50 μM of gomesin (four- to eight-fold below the determined MBC for gomesin). Total RNA from treated and untreated cells was isolated and labeled for hybridization to DNA microarrays. As summarized in Table 2, gomesin treatment modulated the expression of 159 CDS of X. fastidiosa, among which 143 were upregulated and only 16 were downregulated (see Supporting Information, Table S1 for the full list of modulated CDS). Transcript levels of a subset of nine X. fastidiosa CDS were analyzed by RT-qPCR (Table 2), and the results for seven CDS (XF1127, XF1164, XF2367, XF0371, XF0589, XF0833 and XF1984) are in agreement with microarray experiment data. When X. fastidiosa was exposed to the same sublethal concentration of gomesin for shorter periods of time (15 or 30 min), no change in the gene expression profile was observed (data not shown). The CDS differentially expressed upon gomesin exposure belong to diverse functional categories (Fig. 1). Nevertheless, as typically observed in genome-wide transcriptome approaches, the majority encode hypothetical proteins (Fig. 1).

4b) Therefore, the mioC mutant cells may strongly inhibit iron a

4b). Therefore, the mioC mutant cells may strongly inhibit iron acquisition with mutant CFS. We speculated that some chemicals of the wild-type CFS may have stimulated production of pellicle and that mutant CFS may have inhibited production of pellicle and iron utilization in P. aeruginosa. Subsequently, we performed biofilm assay using CFS of the wild-type and mutant cells (Fig. 4c). BTK inhibitor Interestingly, biofilm formation of the mioC mutant cells was induced by 10% wild-type CFS, a result that coincided with data of colony morphology (Fig. 4a and c). Therefore, the wild-type CFS may contain chemicals that

can stimulate production of pellicle EPS and biofilm formation. The swarming motility test was conducted with CFS. Interestingly, the swarming motility using the mioC mutant CFS had a branch form in the wild-type and mioC over-expressed cells (Fig. S4). However, the swarming motility using the wild-type CFS was not changed (data not shown). Therefore, the wild-type and mioC over-expressed cells may have sensed the strong iron depletion and interfered with the iron utilization by mutant CFS. Fld has been found in prokaryotes of all major taxa (Zurbriggen et al., 2007). Fld is typically induced as an adaptive resource under environmental or nutritional hardships such as iron limitation (Zurbriggen et al., 2007). Interestingly,

CHIR-99021 ic50 Fld expression confers tolerance to iron deficit and abiotic stress when introduced in plants (Zurbriggen et al., 2007). Suplatast tosilate Therefore, Fld may be important to the resistance of various stresses in bacteria. We performed PM analysis to investigate the Fld function and our result suggested that the mioC gene mutation changed the physiology

of P. aeruginosa in response to oxidative, metal and antibiotic stresses. Interestingly, the mioC mutant was significantly sensitive to norfloxacin and colistin, whereas the mutant was resistant to ampicillin, polymyxin B and gentamicin. Norfloxacin is a fluoroquinolone antibiotic and functions by inhibiting DNA gyrase (Leigh & Emmanuel, 1984). The mioC gene of P. aeruginosa was induced 1.5-fold under norfloxacin (GDS2317, GEO database), which suggested that the mioC gene might be important for defense against norfloxacin. Each antibiotic has a different mode of action. It remains unclear why different antibiotics work differently to the mutant sensitivity. Because the function of MioC has been characterized for first time, we believed that our global phenotypic analysis will be useful resource to the scientific field. Our data demonstrated that Fld may be linked to biofilm, aggregation and motility under various stresses. It has been reported that flavodoxin gene was induced under biofilm condition of P. aeruginosa (Anderson et al., 2008). The flavodoxin A gene was also induced 5.3-fold in the biofilms of E. coli (Hancock & Klemm, 2007).

PCR products were subjected to capillary electrophoresis on an AB

PCR products were subjected to capillary electrophoresis on an ABI-310 Genetic Analyzer (Applied Biosystems). Each peak was identified according to colour and size and the allele number was assigned based on fragment sizes, as described by Lindstedt et al. (2007). Alleles for which amplicons were absent were designated an allele number of ‘0’. The allele numbers

were entered into bionumerics (Applied Maths) as character values and a dendogram was LDK378 constructed using categorical coefficients and the Ward algorithm. Nucleotide sequencing of the arcA gene (aerobic respiratory control protein A) was performed using the primers and conditions described previously (Leomil et al., 2005). Internal arcA sequences of 513 bp were used for analysis. The sequences were analysed using lasergene software (DNASTAR, Madison, WI) and accelrys gene v2.5 software (Accelrys Ltd, Cambridge, UK). Motility indicating flagellar antigens was found in 36 (58.1%) of the strains. Veliparib research buy Serotyping of H-antigens revealed the presence of the H32 antigen in six and the H11 antigen in 30 strains. The 26 (41.9%) nonmotile

E. coli O26 strains were shown to carry the fliCH11 gene. Fermentation of rhamnose and dulcitol (RDF+) was found with 18 O26:NM strains and with four O26:H32 strains. Thirty O26:H11 and seven O26:NM strains were negative for fermentation of rhamnose and dulcitol (RDF−). Two O26:H32 and one O26:NM strain were positive for fermentation of rhamnose but negative for dulcitol (Table Cyclic nucleotide phosphodiesterase 1). Twenty-three (37.1%)

of the O26 strains produced cytotoxins on Vero cells and were positive for Stx1 (n=15), Stx2 (n=5) or Stx1 and Stx2 (n=3) as tested by enzyme-linked immunosorbent assay. Subtyping of stx genes revealed stx1 in 18 strains, stx2 in seven strains and the mucus activatable stx2d gene in one strain (D618/98). All 56 O26:H11 and O26:NM strains carried an intimin (eae-β) gene. Thus, 33 isolates were identified as EPEC and 23 isolates as EHEC. The six O26:H32 strains were negative for stx- and eae-genes. Production of haemolysins was detected in 51 strains. The enterohaemolytic phenotype (Beutin et al., 2004) and the underlying e-hlyA gene was found with 27 O26:H11 and six O26:NM strains (53.2%). An α-haemolytic phenotype and the α-hlyA gene were present in all 18 RDF+ O26:NM strains (29.0%). The O26:H32 strains were negative for haemolysins and for e-hlyA and α-hlyA genes (Table 1). All O26 strains were tested for additional virulence genes associated with other E. coli pathotypes, STIa, STIb, LTI, ipaH, aggR, bfpB, saa, nleB, stcE, stcE-O103, cdt, and subA. One O26:H32 strain from a dog (C 4050) was positive for STIa and identified as enterotoxigenic E. coli (ETEC).

After all, travelers play a central role in the global spread of

After all, travelers play a central role in the global spread of STIs, especially travelers to tropical and subtropical regions with the highest worldwide prevalence of STIs including HIV.[38, 39] Accidents were the only risk perceived higher after travel but significantly lower by travelers than by experts (Figure 3). Injuries, particularly road traffic accidents, are the second most common cause of death abroad

after cardiovascular disease[40-43] and the leading cause of death of those aged 15 to 29 years worldwide.[44] Over 90% of road traffic fatalities occur in low- and middle-income countries,[44] including BIBW2992 price many tourist destinations in the tropics and subtropics. Higher mortality rates due to vehicle accidents have been found among travelers than among the local population.[45] Travelers are often not familiar with poor road conditions and different, partly insufficient or insufficiently enforced[44] road traffic laws, and they might engage in high-risk behavior during vacation. Despite their potential

for disability[44] and other complications, little is known about the incidence, type, and severity of nonfatal BMS-354825 manufacturer accidents among travelers. Injuries were reported by 6 to 16% of travelers in three different studies,[14, 46, 47] most of them due to road traffic accidents. The most vulnerable groups on the road are pedestrians, (motor) Avelestat (AZD9668) cyclists, and users of unsafe or overcrowded public transport.[44] Some studies suggest that (young) men are most likely to be involved in (fatal) vehicle crashes[43, 48] and engage in more

risk-taking activities than women.[14, 49] However, there were no gender- or age-related differences in the perception of accidents in this study (Figure 4). The post-travel increase in perception is most likely due to observed danger abroad. In other studies, accidents were also rated as a more important health problem during or after a stay abroad than before.[10, 50] In order to raise awareness of this potentially life-threatening risk before departure, information about accidents abroad including practical preventive measures needs to be an integral part of pre-travel health advice. PRISM has only been validated for the assessment of the subjective burden of a present illness, not for the perception of health risks in the near future and past. Nevertheless, a fast, nonverbal visual tool[16] may take into account the emotional quality of (risk) perception which is subjective among both travelers and experts. Statistical correlation of the perception of risks with their incidence was not an option as up-to-date, comparable data were not available or collected. However, the experts’ risk assessment, used as a reference point, proved to be consistent with current literature. Generalization of the results is limited owing to the single location of the study.

The absence of live extracellular bacteria was ensured after subc

The absence of live extracellular bacteria was ensured after subculture on agar plates. At each time point, cells were lysed by 0.1% Triton X-100, and viable intracellular bacteria were counted by plating

serial dilutions of lysates on blood agar plates. Peripheral blood mononuclear cells (106 mL−1) were stimulated with live bacterial cells for 45 min at a ratio of 1 : 10, as in preliminary experiments, this ratio was proved to be the most efficient in cytokine production. Afterwards, extracellular bacteria were lysed by lysostaphin Obeticholic Acid purchase (Sigma), and medium was replaced by CM supplemented with antibiotics. Cells were incubated for selected time points. Each experiment was carried out with mononuclear cells isolated from a single donor and performed in triplicate. Results are based on at least three experiments from different

donors. LPS (10 ng mL−1) was used as a positive control, and PBMCs without stimulants, bacteria or LPS were used to assess spontaneous levels of cytokine secretion (negative control). Supernatants were collected, and the levels of TNFα, IL-1β, IL-6, IL-8, GM-CSF and IL-12p40 were measured by Human Cytokine Multiplex Immunoassay kit manufactured by Linco Research Inc. using Luminex® xMAP™ technology, whereas the levels of IL-12p70, IFN-γ and IL-13 were measured by High Sensitivity Human Cytokine Multiplex Immunoassay Akt inhibitor kit. A five-parameter regression formula was used to calculate

the cytokine concentrations in samples from standard curves. MDMs (2 × 105 mL−1) were stimulated with bacteria at a ratio 1 : 10 for 45 min, extracellular bacteria were lysed by lysostaphin and medium was replaced by CM supplemented with antibiotics. Cells were incubated for additional 12, 24 and 48 h. Supernatants were collected, and the levels of TNFa, IL-1b, IL-6, IL-12p40 and IL-12p70 were assessed. Statistical analysis was performed using spss 17 statistical package (SPSS Inc.). Differences in PIA concentration between biofilm, planktonic and control cells and extracts were assessed by anova test followed by pairwise comparisons. Differential adhesion of biofilm and planktonic cells Oxalosuccinic acid on human MDMs was evaluated using paired t-test. anova test was applied to assess differences in cytokine induction between reference and clinical strains for both parameters (planktonic and biofilm phase). No difference was found (anova P > 0.05); therefore, data analysis was performed after comparing results from all strains. Differences in cytokine concentrations between planktonic and biofilm phase were evaluated using paired t-test. Two-way anova was used to evaluate differences in intracellular survival between biofilm and planktonic phase cells. Statistical significance was set at α = 0.05.

KS, a grant from KCOM Biomedical Sciences Graduate Program to K

K.S., a grant from KCOM Biomedical Sciences Graduate Program to K.S. and an ASDOH summer internship to M.R.C. “
“Osmoadaptation may be an important trait for the pathogenicity of Streptococcus mutans. However, how this organism adapts to changes in osmolality in the oral cavity remains unclear. In this study, we showed that S. mutans utilizes K+ for osmoadaptation, in

which protease maturation lipoprotein (PrtM) plays an important role. Although growth of the wild-type strain was impaired in a hyperosmotic medium [brain heart infusion (BHI) containing AG-014699 order 0.3 M NaCl] compared with that in an unmodified BHI, the prtM mutant grew much more poorly in 0.3 M NaCl BHI. Comparison of growth behavior in the hyperosmotic medium supplemented with different osmoprotectants revealed that only the addition of K+ allowed the bacteria to overcome the impairment of growth caused by the high osmolality. These results suggest that K+ is an important compatible solute for S. mutans. Moreover, K+-associated recovery of growth was not observed for the prtM mutant, indicating that PrtM plays a critical role in the utilization of K+. Quantitative reverse-transcriptase polymerase Selumetinib mouse chain reaction analysis showed that

prtM was induced by osmotic stress, implying that prtM is an osmoresponsive gene. These findings suggest that K+ is an important compatible solute for S. mutans, and that the osmoresponsive lipoprotein PrtM is involved in K+ utilization, contributing to osmoadaptation of S. mutans. “
“Research Group of Industrial Microbiology and Food Biotechnology, Faculty of Sciences and Bioengineering Sciences, Vrije Universiteit, Brussel, Belgium Rhamnolipids are biosurfactants produced by the soil bacterium

Pseudomonas aeruginosa. In addition to their high industrial potential as surface-active molecules, rhamnolipids also have antimicrobial properties. In densely populated habitats, such as the soil, production of antimicrobial compounds is important to inhibit growth of competitors. For the latter, it is crucial for survival to sense and respond to the presence of those antibiotics. To gain a first insight Interleukin-2 receptor into the biological competition involving biosurfactants, we investigated the cellular response of the model organism Bacillus subtilis upon exposure to rhamnolipids by genome-wide transcriptional profiling. Most of the differentially expressed genes can be assigned to two different regulatory networks: the cell envelope stress response mediated by the two-component system LiaRS and the extracytoplasmic function σ factor σM and the CssRS-dependent secretion stress response. Subsequent phenotypic analysis demonstrated a protective function of LiaRS and σM against cell lysis caused by rhamnolipids. Taken together, we present the first evidence that a single antimicrobial compound can simultaneously induce genes from two independent stress stimulons.

Those meeting screening threshold [> 78 mmol/L (140 mg/dL)], the

Those meeting screening threshold [> 7.8 mmol/L (140 mg/dL)], then proceed to a 3-h, 100 g oral glucose tolerance test (OGTT). Diagnosis is made if at least two of the four OGTT values equal or exceed thresholds of 5.3 mmol/L (195 mg/dL) fasting and 10.0, 8.6, and 7.8 mmol/L (180, 155, or 140 mg/dL, respectively) at 1, 2 and 3 h, respectively. Outside of the US, WHO criteria are more commonly employed with the diagnosis being made if the plasma glucose exceeds 7 mmol/L (126 mg/dL) fasting or 7.8 mmol/L (140 mg/dL) at 2 h after a 75-g load. To reconcile these differences, a consensus has recommended the

use of identical numerical glucose thresholds at the fasting, 1- and 2-h time points following the 75-g or 100-g OGTT [95, 180, 155 mg/dL (5.3, 10.0, and 8.6 mmol/L)] for diagnosis. The Hyperglycaemia MLN0128 and Pregnancy Outcome study, a recent international observational study of maternal glycemia in pregnancy and birth outcome, may provide the basis

for consensus about protocols for screening for glucose intolerance and criteria for the diagnosis of hyperglycemia in pregnancy. “
“It is recommended that a structured group education programme such as DAFNE (Dose Adjustment For Normal Eating) is offered to all adults with type 1 diabetes. Such programmes teach the skills of carbohydrate counting and insulin dose adjustment with the aim of improving glycaemic control (HbA1c) without increasing the risk of hypoglycaemia. South West Essex Community Services adult

diabetes service was finding that individuals were not accessing the DAFNE programme for various reasons. A diabetes specialist dietitian and nurse decided to pilot the delivery of two 3-hour group sessions to teach some of the basic carbohydrate counting and insulin dose adjustment skills. Changes in HbA1c pre- and post-intervention were reported for 68 subjects. The four second different intervention arms compared were: those who attended just the carbohydrate counting session (n=14), those who attended both sessions (n=24), those who had attended one or both sessions and then went on to attend DAFNE (n=10), and those who had received no carbohydrate counting education (n=20). Those who had attended one or both of the 3-hour sessions had a mean and absolute reduction in HbA1c compared with the group that had not received any education, although this was not statistically significant. The group that had attended one or both of the 3-hour sessions and DAFNE did achieve a statistically significant reduction in HbA1c compared with the group that had not received any education. Despite several identified limitations to the pilot, it was felt that the delivery of the two 3-hour carbohydrate counting and insulin dose adjustment sessions demonstrated some clinically (if not statistically) significant improvement in HbA1c. Copyright © 2013 John Wiley & Sons.

The concentration of DNA in negative controls was measured at 260

The concentration of DNA in negative controls was measured at 260 nm using

a NanoDrop spectrophotometer. The PCR mixture (25 μL) Bafilomycin A1 datasheet was composed of 12.5 μL of 2 × Combi-PPP mix (Top-Bio Ltd, Prague, Czech Republic, contains hot start-Taq DNA polymerase, 5 mM MgCl2, buffer, deoxyribonucleotides and loader), 0.5 μL 10 μM forward primer, 0.5 μL 10 μM reverse primer, 0.5 μL DNA template and 11 μL water. Thermal programs for primer pairs used in this study are given in Table 1. Nested PCR directed to ITS region was performed using primer pair NSI1/NLB4 in the first amplification and either the pair Tu1sekvF/Tu2sekvR or the pair UncI/UncII in the second. Nested PCR directed to the β-tubulin gene was performed using primers Bt2a/Bt2b in Dasatinib mouse the first amplification and primers tubtubf/elytubr in the second. The annealing temperature originally recommended for

this primer pair is 63 °C, but with this temperature the PCR was not sufficiently sensitive for T. aestivum DNA and the annealing temperature was therefore decreased as indicated in Table 1. In addition, nested PCR was performed using the primers Bt2a/BTAEMB-R in the first amplification and BTAE-F/Bt2b in the second. The same thermal program as indicated for the primer pair BTAE-F/BTAEMB-R in Table 1 was used in both steps of amplification but the annealing temperature was set to 56 °C. The product of the first amplification was always diluted 1 : 100 before being used as a template in the second amplification. Templates were prepared by the Ribose-5-phosphate isomerase addition of small amounts of T. aestivum DNA (extracted from the sample S13, see Appendix S1) into complex nontarget DNA (negative control A). Resulting mixtures contained 2.5, 0.25, 0.025, 0.0025,

0.00025 or 0.000025 ng S13 DNA and 24.5 ng nontarget DNA in 1 μL water. These mixtures were used in nested PCR with primer pairs NSI1/NLB4 (first amplification) and Tu1sekvF/Tu2sekvR (second amplification) as indicated above with annealing at 59 °C. A 5-μL aliquot of the product of PCR amplified using the Tu1sekvF/Tu2sekvR primer pair was mixed with 9 μL water, 1 μL buffer R and 5 U of TaiI restriction endonuclease (New England Biolabs Inc., Ipswich, MA). The mixture was then incubated for 3 h at 65 °C and immediately separated on agarose gel. Soil and ectomycorrhizae samples were collected in the native habitat of T. aestivum, Chuchelský háj, near Velká Chuchle, Prague, Czech Republic. Plant cover was dominated by Carpinus betulus with addition of Fraxinus excelsior, Corylus avellana and Tilia cordata seedlings. Twelve 200 g soil samples were collected on an L-shaped terrain transect at 1 m equidistant points (Fig. 1) from the depth of 0–10 cm (A-horizon, rendzina on silurian lime). Ectomycorrhizae were separated manually from the soil sample.

These clinics, staffed principally by nurses, have been providing

These clinics, staffed principally by nurses, have been providing pre-travel care and consultations to outbound travelers. Here, we describe a model for a travel-clinic operation and management that depend upon the training, oversight, and education of

core nursing staff to maintain professional services designed to reduce travel-related sickness and infectious disease distribution. The University of Utah has created a consulting affiliation with eight clinics managed by four county health departments throughout the state of Utah. Each clinic is an independently operating, approved yellow fever vaccination center run by nurses. Each clinic maintains an affiliation with the University of Utah and pays a fee to receive uniform patient intake forms, the University of Utah’s The Healthy Traveler booklet and Travel Protocol Manual, chart review of each travel visit, on-call consultation, and monthly continuing education. Information from the Centers for Disease Control and Prevention (CDC) Health Information for International Travel (The Yellow Book), Shoreland’s Travax EnCompass, The Healthy Traveler booklet and cultural information

are used for travel visits. The Healthy Traveler booklet, written by the University of Utah travel medicine group, buy AG-014699 summarizes important information for the international traveler. The University of Utah’s Travel Verteporfin solubility dmso Protocol Manual consists of 30 algorithms for travel-related illnesses and vaccinations. Fifteen algorithms pertain to treatment or prevention of travel-related illnesses ranging from altitude sickness to leptospirosis.

Five are dedicated to malaria prophylaxis and self-treatment, and incorporate patient age and weight, and chloroquine or mefloquine resistance areas. Allergies, deep venous thrombosis prevention, jetlag, motion sickness, vaginal candidiasis, and travelers’ diarrhea also are covered. Fifteen additional protocols for vaccine administration are included in the manual. These protocols were developed by an infectious disease physician, certified in travel health, and are updated quarterly or as new travel medicine information becomes available. Each nurse receives initial training and continuing education from the University of Utah. Initial training sessions are conducted by a physician assistant (PA); a medical professional trained, nationally certified, and licensed in the United States, to provide diagnostic, therapeutic, and preventive healthcare services, under the supervision of a physician. Nurse training involves one-on-one meetings in which The Yellow Book, the University of Utah’s Travel Protocol Manual and The Healthy Traveler booklet are reviewed. Topics reviewed include vaccination and prescription protocols as well as common health concerns of the traveler, with an emphasis on malaria, yellow fever, and travelers’ diarrhea.

, 2001 & Pillai et al, 2006) Like StcE, V cholerae TagA is a s

, 2001 & Pillai et al., 2006). Like StcE, V. cholerae TagA is a secreted mucinase and contributes to colonization of the intestinal epithelium (Szabady et al., 2010). The A.  hydrophilia TagA exhibits an additional StcE function by cleaving and localizing C1-INH to the surface of bacterium, increasing the serum resistance Sotrastaurin of the bacterium in vitro. An isogenic deletion mutant of tagA

decreased the mortality of mice compared with wild-type A. hydrophila in a mouse model of peritonitis (Pillai et al., 2006). Thus, StcE-like metalloproteases play a role in the virulence phenotypes of A. hydrophila, V. cholerae and E. coli O157:H7. In this study, we identified stcE as a possible virulence factor in atypical Shigella B13 strains and further characterized this unique cluster of attaching and effacing pathogens. We would like to thank Thomas Whittam, Alison O’Brien, and Fred Blattner for bacterial strains, BKM120 Nancy Strockbine for information regarding the atypical Shigella B13 strains, Jay Bangs for use of his epifluorescence microscope, and Rose Szabady

and Becca Moritz for insightful discussions regarding the project and critical reading of the manuscript. This work was supported by NIH grant RO1 AI051735. “
“Division of Natural Sciences and Mathematics, Transylvania University, Lexington, KY, USA Natural transformation is the main means of horizontal genetic exchange in the obligate human pathogen Neisseria gonorrhoeae. Neisseria spp. have been shown to preferentially take up and transform their own DNA by recognizing a non-palindromic 10 or 12 nucleotide DNA uptake sequence (DUS10 or DUS12). We investigated the ability

of the DUS12 to enhance single-stranded DNA (ssDNA) transformation. Given the non-palindromic nature of the DUS12, we tested whether both strands of the DUS equally enhance transformation. Recombinant single-stranded M13 phage harboring transforming DNA with Progesterone the Watson DUS12, the Crick DUS12, or no DUS (DUS0) were constructed and circular ssDNA was purified. Southern blots of the purified DNA probed with strand-specific oligonucleotide probes showed > 10 000 : 1 ratio of ssDNA to contaminating dsDNA. The Crick strand of the DUS12 enhanced ssDNA transformation 180- to 470-fold over DUS0 ssDNA, whereas the Watson strand of the DUS only modestly enhanced ssDNA transformation in two strains of N. gonorrhoeae. These data confirm that ssDNA efficiently transforms N. gonorrhoeae, but that there is a strand preference and that part of this strand preference is a greater efficiency of the Crick strand of the DUS12 in enhancing transformation. Natural transformation is a widespread mechanism for horizontal genetic exchange used by numerous bacterial species (Johnsborg et al.