High Resolution Electron Microscopy of the Helicobacter pylori Cag Type IV Secretion System Pili Produced in Varying Conditions of Iron Availability

The procedure visualizes the hyper production of CAG type four secretion system pii, which occurs under conditions of iron limitation first culture h pylori under conditions of iron limitation. The second step is to co-culture h pylori with gastric epithelial cells. Next, process the co-culture samples for scanning electron microscopy.

Ultimately high resolution scanning electron microscopy as used to show increased CAG type four secretion system pi eye production under conditions of iron limitation. The technique in this manuscript is important to h pylori related diseases such as gastric cancer because the CAG type four secretion system is associated with increased risk of negative disease outcomes. Thus, a better understanding of the regulation of this important bacterial surface.

Organelle could reveal novel chemotherapeutic targets And the advantage of high resolution scanning electron microscopy versus existing methods such as fluorescent microscopy is that individual type four secretion pill I can be visualized. Individuals new to this method of electron microscopy have problems with the procedure, specifically the wet chemistry as it requires careful timing and a delicate hand On blood. Agar plates grow.

H Pylori PMs, S one bacteria, and its isogenic CAG e mutant, which lacks a functioning type four secretion system. Inoculate cultures and modified Ella broth supplemented with cholesterol to grow overnight. Next seed a GS human gastric epithelial cells onto polylysine treated cover slips in 12 well plates for varying conditions of iron availability.

Dilute the h pylori to an optical density 600 of 0.3 in modified bru broth alone. Media containing 100 micro molars of iron chloride, 200 micromolar of the synthetic iron chelator dipper or 200 micro of dipper plus 200 micro molars of iron chloride culture. The samples for four hours now centrifuge the bacteria at 1000 Gs and Resus suspend the pellets in an equal volume of fresh modified bru broth supplemented with cholesterol.

Measure the bacterial density. Next, infect the epithelial cells with the h pylori at a multiplicity of infection of 20 to one. Perform serial dilutions and plate the bacterial cells onto blood agar plates.

To assess bacterial cell viability, place the co cultures in the cell culture incubator for four hours. Decant the supernatant from the h pylori I and a GS co cultures. Gently wash the adherent cells three times with 0.05 molar sodium coate buffer.

Then fix the samples for two to four hours at room temperature. Next, wash the samples three times with 0.05 molar sodium ca coate buffer. For a secondary fixation add 0.1%osmium tetroxide in 0.05 molar sodium ca coate buffer in two sequential 10 minute fixation steps.

Then after three washes, dehydrate the samples with increased concentrations of ethanol. Place the samples in a critical point dryer machine, then fill the chamber with liquid carbon dioxide. Ethanol is purged from the chamber and the chamber is filled again with liquid carbon dioxide.

The sample is then taken to the critical point of 31.1 degrees Celsius and 1073 PSI now mount the cover slips onto aluminum SEM sample stubs and paint a thin line of colloidal silver at the sample edge for grounding. During SEM imaging, using a sputter coat machine, coat the samples with five nanometers of gold palladium to increase sample secondary electron signal and edge effect. Examine the samples with a field emission gun scanning electron microscope image in a high vacuum mode at a working distance of five to 10 millimeters.

Set the accelerating voltage to five kilovolts. Then set the spot size at two to 2.5. Now tilt the sample between 15 to 25 degrees to achieve a better view of the host pathogen interface for high magnification viewing.

Prioritize the imaging of bacteria adhere to the edges of the epithelial cells for PI life warming bacteria enriched in host pathogen interactions. Open the micrograph files in image J software. Identify pi li as structures form between the bacterial cell and host cell with uniform width of 10 to 13 nanometers and length of 60 to 150 nanometers.

Calibrate the measurement tool by drawing a line with the straight line tool and then clicking on the analyze tab from the dropdown menu. Select set scale and enter the magnification bar value under known distance and set the unit of length to the nanometer. Then click okay.

Now use a straight line tool to draw over the length or width of the pilots and then press control M to measure each pilots and record the measured values into a spreadsheet program. Use previously established length and width parameters to disregard features that do not fit the profile of CAG type four secretion system. Then quantify the number of PI I based on values that are within range statistically analyzed a quantification of the PI LI using a two-tailed student T-test.

In this experiment, h pylori were cultured in iron depleted conditions using the synthetic chelator dip parital at concentrations that do not significantly inhibit growth. The bacteria produced numerous CAG type four secretion system PII when co-culture with human gastric cells. Conversely, when an exogenous source of nutrient iron is present, the formation of CAG type four secretion system PII is repressed.

Quantification of the PII at the host pathogen interface reveals that in conditions of iron restriction, h pylori exhibits a twofold increase in CAG type four secretion system PI eye, the percent pileated cells increases by 11%compared to cells grown in medium alone. Interestingly, although the CAG type four secretion system activity as measured by host IL eight secretion is enhanced under conditions of iron restriction and repressed under conditions of excess iron availability, PI LI dimensions remain consistent among all conditions of iron availability. Consistent with the involvement of CAG type four secretion system iron availability does not change the biogenesis of PI LI on the surface of a CAG e mutant After its development.

This SEM technique paved the way for researchers within the field of the CAG type four secretion system to explore protein localization. With respect to the CAG type four secretion system pillows. Recently it's been discovered that the effector protein CAG a localizes to the tip of the type four secretion pill.I.