Cool Killers: The Beauty of Deadly Pathogens 1....

Cool Killers: The Beauty of Deadly Pathogens

1. Putting a New Twist on Speciation: Campylobacter Cells Reunite At Last

C. jejuni and C. coli are microaerophilic bacteria that have a characteristic corkscrew shape. Both belong to the same genus, Campylobacter (which means “twisted bacteria”). They are the foodborne pathogens responsible for the campylobacteriosis infection, which can cause periodontitis, dysentery, and inflammatory diarrhea.

Scientists recently discovered that C. jejuni and C. coli are beginning to merge into one species through a process called hybridization. Though they share about 85 percent of their genetic code, the two species have traditionally been very different, having adapted to fill specific niches inside the guts of chicken, cows, and other livestock.

But because of industrialized farming—which involves keeping livestock in ultra-close proximity—C. jejuni and C. coli have been pushed closer together, facilitating the exchange of genes through a process called hybridization.

This false-color electron-microscope image shows Campylobacter cells clumping together.

2. High-Tailing It: Listeria Moving Through a Cell

Listeria monocytogenes, a rod-shaped bacterium, is one of the world’s deadliest foodborne pathogens. It causes listeriosis, a group of life-threatening diseases that include meningitis, encephalitis, pneumonia, septicemia, and intrauterine or cervical infections in pregnant women. The latter account for around 27 percent of the 500 listeria deaths that occur in the U.S. every year.

L. monocytogenes infects and moves through white blood cells using actin rockets, also known as “comet tails.” The rockets work like this: A protein anchored to the bacterium’s membrane triggers the rapid polymerization of the protein actin; this provides an explosive boost, so the bacterium can push through the membrane of white blood cells and burst out to infect another cell.

In this image, the bacteria (shown in red) are traveling around a cell using their bright actin rockets.

3. The Pretty Invasion: Endothelial Cells Infected by Cytomegalovirus

More commonly known as human herpesvirus 5 or HCMV, cytomegalovirus is the most frequently transmitted intrauterine infection and can result in serious disabilities at birth, though most people will exhibit only mild symptoms or none at all.

About 1 in 150 children is born with congenital CMV, and 1 in 750 children suffers from permanent disabilities due to the infection. This multicolor immunofluorescence image shows human endothelial cells being infected by cytomegalovirus.

4. Microcellular Warfare: When Neutrophils Attack

Streptococcus pyogenes, a spherical bacteria that typically grows in long chains, can cause minor infections like impetigo to potentially deadly diseases like streptococcal toxic shock syndrome. The cells possess a number of defense mechanisms, known as virulence factors, which allow them to evade the host’s immune system and spread through its tissues.

In this image, human neutrophils—white blood cells that are one of the body’s first lines of defense—are engulfing S. pyogenes cells through a process known as phagocytosis.

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Posted on Thursday, 15 March
Tagged as: Science Pathogens Medicine

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