Journal: Applied and Environmental Microbiology

Article Title: Environmental Stress-Induced Bacterial Lysis and Extracellular DNA Release Contribute to Campylobacter jejuni Biofilm Formation

doi: 10.1128/AEM.02068-17

Figure Lengend Snippet: Biofilm formation and release of extracellular DNA (eDNA) by wild-type C. jejuni strains (i.e., human 10, 81-116, ATCC 33560, 87-95, NCTC 11168, 1658, and F38011) under optimal, aerobic, and starvation conditions. (A) The level of biofilm formation was evaluated using crystal violet staining. The stained biofilm was released using 95% ethanol and determined by monitoring the value of OD595. (B to D) The concentration of eDNA during biofilm formation under optimal conditions (B), aerobic conditions (C), and starvation conditions (D) over 3 days was quantified using SYBR green I dye on the basis of a standard curve generated using a series of 10-fold dilutions of Lambda DNA from 80 μg/ml to 0.156 μg/ml.

Article Snippet: C. jejuni F38011 was used as the representative strain for the following study due to its intense biofilm formation and remarkable response to different environmental conditions. fig ft0 fig mode=article f1 fig/graphic|fig/alternatives/graphic mode="anchored" m1 Open in a separate window FIG 1 caption a7 Biofilm formation and release of extracellular DNA (eDNA) by wild-type C. jejuni strains (i.e., human 10, 81-116, ATCC 33560, 87-95, NCTC 11168, 1658, and F38011) under optimal, aerobic, and starvation conditions. (A) The level of biofilm formation was evaluated using crystal violet staining.

Techniques: Staining, Concentration Assay, SYBR Green Assay, Generated, Lambda DNA Preparation

Journal: Applied and Environmental Microbiology

Article Title: Environmental Stress-Induced Bacterial Lysis and Extracellular DNA Release Contribute to Campylobacter jejuni Biofilm Formation

doi: 10.1128/AEM.02068-17

Figure Lengend Snippet: Biofilm formation and release of extracellular DNA (eDNA) by wild-type C. jejuni F38011 and the corresponding spoT, recA, and flaAB deletion mutants under optimal, aerobic, and starvation conditions. (A) The level of biofilm formation was evaluated using crystal violet staining. The stained biofilm was released using 95% ethanol and determined by monitoring the value of OD595. (B to D) The concentration of eDNA during biofilm formation under optimal conditions (B), aerobic conditions (C), and starvation conditions (D) over 3 days was quantified using SYBR green I dye on the basis of a standard curve generated using a series of 10-fold dilutions of Lambda DNA from 80 μg/ml to 0.156 μg/ml.

Article Snippet: C. jejuni F38011 was used as the representative strain for the following study due to its intense biofilm formation and remarkable response to different environmental conditions. fig ft0 fig mode=article f1 fig/graphic|fig/alternatives/graphic mode="anchored" m1 Open in a separate window FIG 1 caption a7 Biofilm formation and release of extracellular DNA (eDNA) by wild-type C. jejuni strains (i.e., human 10, 81-116, ATCC 33560, 87-95, NCTC 11168, 1658, and F38011) under optimal, aerobic, and starvation conditions. (A) The level of biofilm formation was evaluated using crystal violet staining.

Techniques: Staining, Concentration Assay, SYBR Green Assay, Generated, Lambda DNA Preparation

Journal: Applied and Environmental Microbiology

Article Title: Environmental Stress-Induced Bacterial Lysis and Extracellular DNA Release Contribute to Campylobacter jejuni Biofilm Formation

doi: 10.1128/AEM.02068-17

Figure Lengend Snippet: Confocal micro-Raman spectroscopy monitors the development of C. jejuni F38011 biofilm in the microfluidic “lab-on-a-chip” platform. C. jejuni F38011 biofilm was cultivated in a microfluidic device, and the chemical component was determined at 72 h, 120 h, 168 h, and 216 h using confocal micro-Raman spectroscopy coupled with a 532-nm-wavelength laser. (A) Prominent Raman peaks during biofilm formation. (B) Variations in the intensity of the corresponding Raman peaks (746, 918, 968, 1,123, 1,168, 1,370, 1,580, and 1,643 cm−1) over time. The Raman peaks derived from nucleic acid components (746 and 1,580 cm−1) are shown in black, and the Raman peaks derived from other components (i.e., proteins, lipids, and polysaccharides) are shown in gray.

Article Snippet: C. jejuni F38011 was used as the representative strain for the following study due to its intense biofilm formation and remarkable response to different environmental conditions. fig ft0 fig mode=article f1 fig/graphic|fig/alternatives/graphic mode="anchored" m1 Open in a separate window FIG 1 caption a7 Biofilm formation and release of extracellular DNA (eDNA) by wild-type C. jejuni strains (i.e., human 10, 81-116, ATCC 33560, 87-95, NCTC 11168, 1658, and F38011) under optimal, aerobic, and starvation conditions. (A) The level of biofilm formation was evaluated using crystal violet staining.

Techniques: Raman Spectroscopy, Lab-on-a-Chip, Derivative Assay

Journal: Applied and Environmental Microbiology

Article Title: Environmental Stress-Induced Bacterial Lysis and Extracellular DNA Release Contribute to Campylobacter jejuni Biofilm Formation

doi: 10.1128/AEM.02068-17

Figure Lengend Snippet: Addition of genomic DNA extracted either from Campylobacter or Salmonella had a concentration-dependent stimulation effect on biofilm formation of C. jejuni F38011; the precoating layer formed by DNA extracted either from Campylobacter or Salmonella did not contribute to the development of biofilm formation of C. jejuni F38011. Genomic DNA of C. jejuni F38011 or S. Typhimurium SL1344 was separately extracted and added for biofilm formation. (A and B) To form a precoating layer, 200 μl of DNA of Salmonella (A) or C. jejuni (B) at different concentrations was added into each well of the 96-well plate and maintained for 4 h. The unbounded DNA was washed out before the addition of C. jejuni F38011 culture. (C and D) To directly add DNA for biofilm formation, DNA of Salmonella (C) or C. jejuni (D) was mixed with C. jejuni F38011 culture to reach a certain final concentration and 200 μl of this mixed culture was added into the 96-well plate. The plate was then cultivated in a microaerobic environment at 37°C for up to 72 h.

Article Snippet: C. jejuni F38011 was used as the representative strain for the following study due to its intense biofilm formation and remarkable response to different environmental conditions. fig ft0 fig mode=article f1 fig/graphic|fig/alternatives/graphic mode="anchored" m1 Open in a separate window FIG 1 caption a7 Biofilm formation and release of extracellular DNA (eDNA) by wild-type C. jejuni strains (i.e., human 10, 81-116, ATCC 33560, 87-95, NCTC 11168, 1658, and F38011) under optimal, aerobic, and starvation conditions. (A) The level of biofilm formation was evaluated using crystal violet staining.

Techniques: Concentration Assay

Journal: Applied and Environmental Microbiology

Article Title: Environmental Stress-Induced Bacterial Lysis and Extracellular DNA Release Contribute to Campylobacter jejuni Biofilm Formation

doi: 10.1128/AEM.02068-17

Figure Lengend Snippet: Lysis level of C. jejuni cells was stimulated by aerobic conditions and inhibited by starvation conditions during biofilm formation. The presence of genomic DNA is an indicator of bacterial lysis. After 3 days of biofilm cultivation, the genomic DNA in the supernatant and biofilm of the C. jejuni wild-type strain and spoT, recA, and flaAB deletion mutant strains was purified. The relative levels of content of genomic DNA in the supernatant and biofilm were individually determined via real-time quantitative PCR (qPCR) using the rpoA housekeeping gene. The lysis level was calculated by dividing the value corresponding to the genomic DNA content in the supernatant by the sum of the values corresponding to the genomic DNA content in the supernatant and in the biofilm.

Article Snippet: C. jejuni F38011 was used as the representative strain for the following study due to its intense biofilm formation and remarkable response to different environmental conditions. fig ft0 fig mode=article f1 fig/graphic|fig/alternatives/graphic mode="anchored" m1 Open in a separate window FIG 1 caption a7 Biofilm formation and release of extracellular DNA (eDNA) by wild-type C. jejuni strains (i.e., human 10, 81-116, ATCC 33560, 87-95, NCTC 11168, 1658, and F38011) under optimal, aerobic, and starvation conditions. (A) The level of biofilm formation was evaluated using crystal violet staining.

Techniques: Lysis, Mutagenesis, Purification, Real-time Polymerase Chain Reaction

Journal: Applied and Environmental Microbiology

Article Title: Environmental Stress-Induced Bacterial Lysis and Extracellular DNA Release Contribute to Campylobacter jejuni Biofilm Formation

doi: 10.1128/AEM.02068-17

Figure Lengend Snippet: DNase I treatment before bacterial initial attachment prevented C. jejuni biofilm formation and DNase I treatment of the well-developed C. jejuni biofilm disrupted biofilm structure, leading to the reduction of biomass. To treat biofilm at the initial attachment stage, DNase I was mixed with C. jejuni culture to reach a final concentration of 2 U/ml and then added into the 96-well plate for biofilm formation. To treat the well-developed biofilm in the 96-well plate, 200 μl of DNase I solution (2 U/ml) was added into a well with a 3-day cultivated C. jejuni biofilm. The treatment was maintained for 15 min at room temperature. The reduction level of biofilm was evaluated using the aforementioned crystal violet staining assay. Asterisks denote significant difference (P < 0.05).

Article Snippet: C. jejuni F38011 was used as the representative strain for the following study due to its intense biofilm formation and remarkable response to different environmental conditions. fig ft0 fig mode=article f1 fig/graphic|fig/alternatives/graphic mode="anchored" m1 Open in a separate window FIG 1 caption a7 Biofilm formation and release of extracellular DNA (eDNA) by wild-type C. jejuni strains (i.e., human 10, 81-116, ATCC 33560, 87-95, NCTC 11168, 1658, and F38011) under optimal, aerobic, and starvation conditions. (A) The level of biofilm formation was evaluated using crystal violet staining.

Techniques: Concentration Assay, Staining

Journal: Applied and Environmental Microbiology

Article Title: Environmental Stress-Induced Bacterial Lysis and Extracellular DNA Release Contribute to Campylobacter jejuni Biofilm Formation

doi: 10.1128/AEM.02068-17

Figure Lengend Snippet: DNase I treatment reduced the coverage and volume of C. jejuni biofilm. The well-developed (3-day) C. jejuni F38011 biofilm on a nitrocellulose membrane was treated with DNase I solution (2 U/ml) for 15 min and then air-dried for the analysis of atomic force microscopy. (A) Coverage reduction caused by DNase I treatment. (B) Volume reduction caused by DNase I treatment. Asterisks denote significant difference (P < 0.05).

Article Snippet: C. jejuni F38011 was used as the representative strain for the following study due to its intense biofilm formation and remarkable response to different environmental conditions. fig ft0 fig mode=article f1 fig/graphic|fig/alternatives/graphic mode="anchored" m1 Open in a separate window FIG 1 caption a7 Biofilm formation and release of extracellular DNA (eDNA) by wild-type C. jejuni strains (i.e., human 10, 81-116, ATCC 33560, 87-95, NCTC 11168, 1658, and F38011) under optimal, aerobic, and starvation conditions. (A) The level of biofilm formation was evaluated using crystal violet staining.

Techniques: Microscopy

Journal: Applied and Environmental Microbiology

Article Title: Environmental Stress-Induced Bacterial Lysis and Extracellular DNA Release Contribute to Campylobacter jejuni Biofilm Formation

doi: 10.1128/AEM.02068-17

Figure Lengend Snippet: Spatial distribution of C. jejuni cells, Salmonella cells, and extracellular DNA (eDNA) within a Campylobacter-Salmonella dual-species biofilm formed in the microfluidic platform. Fluorescence microscopy was applied to determine the spatial distribution of eDNA and bacterial cells in a dual-species Campylobacter-Salmonella biofilm. After a 3-day cultivation, 30 nM DAPI solution was injected into the microfluidic device to stain eDNA in the biofilm. Images were collected at multiple channels: 405 nm (blue for DAPI signal), 488 nm (green for GFP signal), and 543 nm (red for RFP signal). Within this Campylobacter-Salmonella dual-species biofilm, C. jejuni cells were mainly located at the bottom whereas Salmonella cells were mainly located at the top layer. The eDNA mainly assembled and formed several eDNA-rich areas and maintained a spatial distance between C. jejuni and Salmonella in the biofilm.

Article Snippet: C. jejuni F38011 was used as the representative strain for the following study due to its intense biofilm formation and remarkable response to different environmental conditions. fig ft0 fig mode=article f1 fig/graphic|fig/alternatives/graphic mode="anchored" m1 Open in a separate window FIG 1 caption a7 Biofilm formation and release of extracellular DNA (eDNA) by wild-type C. jejuni strains (i.e., human 10, 81-116, ATCC 33560, 87-95, NCTC 11168, 1658, and F38011) under optimal, aerobic, and starvation conditions. (A) The level of biofilm formation was evaluated using crystal violet staining.

Techniques: Fluorescence, Microscopy, Injection, Staining