Could Salmonella Bacteria Kill Tumors?
ScienceDaily (Sep. 8, 2009) — Salmonella is regarded as a bad guy. Hardly a summer passes without reports of severe salmonella infections via raw egg dishes or chicken. But salmonella may not only harm us -- in the future, it may even help to defend us against cancer. Researchers may soon have a way to make the bacteria migrate into solid tumors in order to make it easier to destroy them. Furthermore, in laboratory mice, the bacteria independently find their way into metastases, where they can also aid clearance of the cancer.


In the scientific journal PLoS One, Sara Bartels and Siegfried Weiss of the Helmholtz Centre for Infection Research (HZI) in Braunschweig, Germany now show how the bacteria migrate into tumors. A messenger substance from the immune system is the door opener: It makes blood vessels in the cancerous tissue permeable; enabling the bacteria to conquer and destroy the tumor. Simultaneously, blood streams from the vessels into the cancerous tissue, a so-called necrosis develops – and the tumor dies. “This influx of blood was the starting point for our investigations,” says Siegfried Weiss, Head of the Molecular Immunology group at the HZI.

“There is an immunological messenger present during bacterial elicited inflammation that causes this kind of reaction. We searched for it – and found it.” This messenger is named after its role in the immune system: tumor necrosis factor, TNF-alpha for short. Immune cells produce TNF-alpha when recognising salmonella, thus alarming other immune cells. This inflammatory reaction leads to an increased blood vessels permeability an action that also occurs in a tumor: TNF-alpha has an easy task here because the blood vessels in cancer differ fundamentally from healthy arteries or veins. They are irregularly built, porous, partially with dead ends. A small amount of TNF-alpha is subsequently enough to dissolve the walls of the blood vessels in the tumor and allow the blood to stream into the cancerous tissue.

The scientists hope to be able to modify salmonella so they can be used in tumor therapy. The aim is for the bacteria to migrate specifically into tumors and cause them to die. The attractiveness of this way of destroying tumors is the lifestyle of salmonella. They can live almost everywhere, including tissues, which are badly supplied with blood and thus have hardly any oxygen supply. And it is precisely these areas that are scarcely reachable in a cancerous ulcer using common cancer therapies: chemotherapeutics cannot be transported to an area where there is no blood flow. And even radiation therapy requires oxygen for its reactions in the tissue.

The phenomenon of bacteria attacking tumors has been known to scientists for a long time. However, a cancer therapy with potential pathogens has been unthinkable before now. The risk of the patient dying due to an infection was too high. “We have obtained an important indication of how bacteria migrate into tumors. We can now try to manipulate these bacteria to use them in cancer therapy without causing deadly infections,” says Sara Bartels.

Bacteria Take On Completely New Flat Shape To Fit Through Nanoslits
ScienceDaily (Sep. 9, 2009) — It appears that bacteria can squeeze through practically anything. In extremely small nanoslits they take on a completely new flat shape. Even in this squashed form they continue to grow and divide at normal speeds. This has been demonstrated by research carried out at TU Delft's Kavli Institute of Nanoscience. The results will be appearing this week in the online edition of the scientific journal Proceedings of the National Academy of Sciences (PNAS) and as the cover article in the September 1 print issue of PNAS.


Using nanofabrication, Delft scientists made minuscule channels, measuring a micrometer or less in width and 50 micrometer in length, on a silicon chip between tiny chambers containing bacteria. Subsequently they studied the behaviour of Escherichia. coli and Bacillus. subtilis bacteria in this artificial environment. The bacteria were genetically modified so that they were fluorescent and could easily be followed using a special microscope.

Squashed flat

Under normal circumstances these bacteria swim and this research showed that they retain this motility in surprisingly narrow channels. They swam just as actively as usual even in channels that were only 30 percent wider than their own diameter (of about 1 micrometer). In even narrower submicron channels the bacteria stopped swimming, and an unexpected effect took place: The bacteria were able to make their way through ultra-narrow passageways in another manner, that is by growing and dividing. The researchers found that this way, E. coli bacteria could squeeze through narrow slits that were only half their own diameter in width.

Post-doctoral researcher, Jaan Männik said, "This took us totally by surprise. The bacteria become completely flattened. They have all sorts of peculiar shapes both in the channels and when they finally come out at the other side. What is really remarkable, however, is that in the channels, and therefore under extreme confinement, they continue to grow and divide at normal speeds. Apparently their shape is not a determining factor for these activities."

Use a strong password and keep it a secret
The key to accessing the network is your password. In order to reduce the chance of a computer or another person guessing your password, you should choose a strong one. A strong password is a combination of letters, numbers, and symbols that is NOT a word or common phrase. Your password should not be a word from the dictionary or one that someone with a little personal knowledge of you might guess (i.e. your child’s name or your phone number). As well, the password you use to access University resources should be unique from those you use to access resources outside the University, and, most importantly, you should never share your password with anyone or write it down anywhere.

University support technicians, including those at the USM HelpDesk, will NEVER ask you what your password is. One of the most common password-stealing tricks employed by hackers and information thieves is to call on the phone and impersonate a company's help desk staff or network administrator. Don't fall for it. If you receive a call or email requesting your password, you should refuse to provide it and immediately report the incident to the HelpDesk (780-4029 or helpdesk@usm.maine.edu).

In situations where you initiated a call to the USM HelpDesk, the technician assisting you may set a temporary password on your account for their use. They will only do that with your approval, and only if other troubleshooting measures have failed and using your credentials will allow the technician to test the problem firsthand. After the troubleshooting is complete, you will be required to change your password immediately.

Do not let another person use your user account
Your user account represents all the computing resources that you personally have been authorized to access. By letting someone else use your user account, you are letting them access resources for which they do not have approval. Anything that they may do will, ultimately, be your responsibility.

Use network drives for sensitive or important files
All files that contain sensitive information, or that are critical to the University's work should be stored on a network drive – but only as long as they are needed. These are usually the drives with higher letters in the alphabet above “F:\”. Why use network drives?

Security: Anyone with physical access to a computer can, one way or another, get access to the files stored on the computer’s local drives — A:\ through E:\.
Data Protection: If a computer "crashes," then all data on the local drives might be lost. Files stored on the network drives are backed up on a nightly basis. In the event data is lost due to some disaster, there is a much greater chance that the data can be restored to a relatively recent state.
Lock your computer when away from your desk during the day
The world's strongest password won't matter at all if you walk away from your desk, even for a few minutes, and leave your computer on and unlocked. For computers running Windows 2000 and Windows XP, press Ctrl-Alt-Del keys simultaneously and select Lock Workstation. When you return to your desk, you will have to enter your Novell password to unlock the computer. For Mac workstations using OS X, you can password-protect your account under "System Preferences" to be activated every time the computer goes into Sleep mode.

While you are at your computer you should arrange your work area so that your screen cannot be viewed by casual visitors. This can alleviate a lot of inadvertent viewing of personal or confidential information.

Shutdown your computer when you leave for the day
When you leave the office each night, turn off your computer. A computer that is off cannot be infected or compromised by attacks from other computers.

Use encryption for viewing and exchanging sensitive data
You should always use encryption to view web sites containing sensitive data. You can tell if a web site is using encryption if the web address begins with "https".

If you have created a web site that collects sensitive data, you should be sure that the site forces users to use encryption when submitting data and that the data, once submitted, is being stored securely.

Remember, email is not encrypted and therefore should not be used to exchange sensitive data. If you have need to transfer sensitive data via email, the information should be sent in a password-protected zip file attachment. Tell the recipient the password in person or via telephone, not via email. For a corollary caution see #8.

Finally, remember that when using wireless connections, they are not secure. Any data you may be accessing can be captured someone using similar technology. When accessing data and information that is confidential, you should only use a connection that is hardwired to your machine.

Do not install unapproved software
Only the programs found in Start > USM Apps > Install have been approved for installation on University computers. If you feel you need to install a piece of software not found there, you must get the approval of DoIT staff first.

Do not install free software found on the Internet. These programs often present a great security risk. To avoid this, be very wary, when surfing the Internet, of pages that offer anything for free by just “clicking here”. If unexpected pop up messages are displayed while surfing the Internet, use the “X” in the upper right corner of the message to close it.

Think before opening email attachments
Be suspicious of emails with attachments that you were not expecting to receive, even if they appear to be from someone you know. If it appears to be from someone you know, before you open it, contact them and confirm that they intended to send you the attachment. For a corollary caution see #6.

Schedule an antivirus scan of your computer
Most of us have a weekly staff meeting. At these times your computer is usually sitting idle in your office. That is a perfect time to schedule an antivirus scan of your computer to run. These can run while your computer is locked. If any viruses are detected, please report them to the HelpDesk.

Be careful using Internet Explorer
We feel it is best to only use Internet Explorer for those websites that require it (i.e., PeopleSoft) and use a different browser for all other web activity. The Internet Explorer web browser that comes with Microsoft Windows seems to have a new security flaw almost every month. While we apply patches for these flaws as quickly as possible, DoIT recommends the use of Mozilla’s Firefox, available via Start > USM Apps > Install > Firefox Web Browser. You need to get approval before installing any other browser.