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The Cell’s Muscles and BonesTorsten Wittmann

Cell movement begins with lamellipodia. A thin sheet of actin filaments (light purple) that stretches out to the cell’s periphery, lamellipodia generate pushing forces that drive the cell forward. Microtubules (cyan) can barely penetrate this actin network, but they direct cell motility in other ways, such as controlling cell adhesion and acting as the cell’s internal compass.

Lamellipodia are not the only way for cells to get about— plasma membrane blebs can also drive cell migration. Once thought to be restricted to dying cells, these spherical membrane protrusions are now thought to be particularly important in tumor cells, which have been shown to switch between the lamellipodia- and bleb-based motility.

Image: Cells from culture were imaged with a JEOL 6700 Field Emission Scanning Electron Microscope, and then false colored with Adobe Photoshop. By Anne Weston, Cancer Research UK. (Cell.com)

Harnessing bacteria to move microscopic gears and ratchets

Computer simulations at OIST suggest new applications in industry by harnessing active microscopic particles in fluids. Previous research has already demonstrated that substantial quantities of self-motile or active agents such as bacteria in a fluid environment can be harnessed to do mechanical work like moving microscopic gears and ratchets. Bacteria as well as algae can also be used to transport or displace matter in fluidic environments.

The new research recently published by scientists at the Okinawa Institute of Science and Technology Graduate University (OIST) in the journal Soft Matter carefully examines the relationships between self-motile and passive or inert agents to determine possibility of creating fully synthetic systems by looking into examples of biology interacting with mechanical mechanisms. Denis F. Hinz and Professor Eliot Fried of the OIST Mathematical Soft Matter Unit created the necessary models and investigated how such mixtures can work to achieve desired effects.

Denis F. Hinz, Alexander Panchenko, Tae-Yeon Kim, Eliot Fried. Motility versus fluctuations in mixtures of self-motile and passive agents. Soft Matter, 2014; 10 (45): 9082 DOI: 10.1039/C4SM01562B

The three distinct flow pattern phases found through computer simulations by Denis F. Hinz and Eliot Fried at OIST are shown. From left to right, mesoturbulant, polar flock and voritcal are visualized. Credit: OIST

She’s a snap clone designed for cyborg applications who enjoys ice and welding fuel.

They’re a positronic intelligence housed in a decommissioned military support chassis with a fondness for late 23rd century Earth philosophy.

Together, they are utterly ineffective at stopping the traitor from delaminating the supermatter engine crystal lattice and blowing up Engineering.

Gonorrhea infections start from exposure to seminal fluid

Researchers have come a step closer to understanding how gonorrhea infections are transmitted. When Neisseria gonorrhoeae, the bacteria responsible for gonorrhea, are exposed to seminal plasma, the liquid part of semen containing secretions from the male genital tract, they can more easily move and start to colonize. The research, led by investigators at Northwestern University in Chicago, appears in mBio®, the online open-access journal of the American Society for Microbiology.

"Our study illustrates an aspect of biology that was previously unknown," says lead study author Mark Anderson. "If seminal fluid facilitates motility, it could help transmit gonorrhea from person to person."

Gram stain of Neisseria gonorrhoeae, the agent of the STD gonorrhea. The bacteria are seen as pairs of  cocci (diplococci) in association with host pmn’s (polymorphonuclear leukocytes). Gonorrhea is the second most prevalent STD in the U.S. behind chlamydia. The bacterium has multiple determinants of virulence including the ability to attach to and enter host cells, resist phagocytic killing and produce endotoxins which eventually lead to an intense inflammatory response. CDC.

Going against the flow: Targeting bacterial motility to combat disease

Mycoplasma gallisepticum causes chronic respiratory disease in birds and is related to the human pathogen Mycoplasma pneumoniae, the causative agent of human bronchitis and pneumonia. Over the course of evolution, mycoplasmas have thrown most of their genetic material over board, resulting in one of the smallest bacterial genomes. This is what makes them such efficiently adapted pathogens in humans and animals.

The gliding motility of M. gallisepticum was first observed in the 1960s.  First author Ivana Indikova and study director Michael Szostak of the Institute of Microbiology at the Vetmeduni Vienna have found that gliding requires the proteins GapA, CrmA and Mgc2.

"If the bacteria are missing one of these three proteins, they are no longer able to move. We want to know if non-motile mycoplasmas are less infectious. If that were the case, we could target the motility genes to turn them off and so render the bacteria harmless," Szostak explains.

The ability to glide gives the pathogens certain advantages. It remains unknown, however, which stimuli M. gallisepticum responds to when gliding.

Szostak suspects: “Most mycoplasmas cannot glide. Gliding species have so far been found only in the respiratory and genital tracts - places in which there is a directional mucus flow. We believe that the gliding bacteria possibly move against this flow in order to reach deeper-lying regions of the body. We are currently planning further experiments to attempt to answer this question.”

Gliding motility could even contribute to the ability of mycoplasmas to invade and traverse body cells. This could allow them to safely evade the body’s immune system and the infection could spread efficiently through the host body.

Caption: This image shows Mycoplasma gallisepticum on epithelial cells of a chicken trachea.  Credit: Photo: Michael Szostak / Vetmeduni Vienna

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Motile's first single from Princess, “Lavaboyz”!
a video by Giulia Essyad

DFW word of the day

Motile - ADJECTIVE:

1. Biology Moving or having the power to move spontaneously: motile spores.

2. Psychology Of or relating to mental imagery that arises primarily from sensations of bodily movement and position rather than from visual or auditory sensations.


ETYMOLOGY:
Latin m tus, motion (from past participle of mov re, to move; see motion) + -ile1

OTHER FORMS:
mo·til i·ty (m -t l -t ) KEY (Noun)