Microbe Spotlight: Week 7

NDSU Microbiology
by NDSU Microbiology

The students in Infectious Disease Pathogenesis Lab will be blogging about the strange and wonderful this semester. This week's guest bloggers are: Sierra Shoman, TJ Tran, Emma Sioringas, and Leiah Smolley. Check back next week for a new selection of microbe spotlights.

Psychrobacter cryohalolentis

Psychrobacter cryohalolentis is a gram-negative coccobacilli that is often found in pairs. It is non-pigmented, non-spore-forming and non-motile. This bacterium likes aerobic environments, and is also halotolerant and psychrophilic. P. cryohalolentis was isolated from forty thousand year old permafrost in Siberia. It was discovered by David Gilichinsky, Russian Academy of Sciences. The temperature in this permafrost ranges from -9 to -11°C. Close relatives of this bacterium are opportunistic pathogens in animals and humans and have been isolated as causes of infections. This bacterium has not been found in a patient, but some scientists believe that if given the chance it could also be an opportunistic pathogen.

The K5 strain of this bacterium has been sequenced. It has 2,575 genes, and is approximately 3.1 MB in size. This strain was studied because it has the ability to reproduce at -10 °C, the generation time is 39 days, and it has rapid growth at low temperatures. These traits make this a good bacterium to help better understand protein expression at subzero temperatures. This information will help us develop new ways to store and process food so that it does not spoil when frozen. It will also teach us about bacterial survival and microorganism stress response.

This bacterium is also of interest because it could potentially be able to survive on Mars. One study synthesized the environmental conditions on Mars and showed that P. cryohalolentis tolerated ultraviolet irradiation, high desiccation, low temperature, and low atmospheric pressure. This study was conducted because some experts think that bacteria may compromise the search for life beyond Earth if these organisms are able to propagate on other planets. This brings up ethical questions about investigating other planets and if we are doing harm by bringing foreign life forms to these other planets.

By Sierra Shoman

Image: Brocken Inaglory; Licence

Wigglesworthis glossinidia

Wigglesworthia glossinidia is a gram-negative bacillus that lives in the gut of the tsetse fly. It is an obligate mutualist meaning that is can only survive as an endosymbiont of a host organism. It plays an important role in the life of the tsetse fly, providing it with vital nutrients that the fly cannot get from the blood it consumes and playing a role in the development of the fly’s immune system.

The importance of this microbe is twofold in the sense that it has provided insight into mutualistic endosymbiotic relationships as well as a possible means of controlling trypanosomiasis, a disease transmitted by the tsetse fly. Also known as human African sleeping sickness, trypanosomiasis is an infection by trypanosomes (parasitic protozoa). This disease can be lethal and is responsible for human as well as animal death in central and western Africa. Advancements in diagnosis and treatment have led to a positive outlook in disease management, and the WHO has projected that this disease will not be a major public health issue by 2020.

By TJ Tran

Image: Tam Nguyen; License

SM1 Euryarchaeon

SM1 Euryarchaeon is an archaeon that lives in cold sulfuric springs in Europe. It was first discovered in Germany in sulfurous streamlets. These microbes form a
string-of-pearls appearance that can be seen macroscopically. The interior of the pearls are formed from SM1 Euryarchaeon. The exterior and the connective threads are composed of bacteria from the genus Thiothrix or the IMB1 ɛ-proteobacteria. SM1 Euryarchaeon and Thiothrix are believed to have a symbiotic relationship.

SM1 Euryarchaeon has an appendage never seen before, which researchers have named hamus (pl. hami). The hami surround the cells and entangle them to their neighbors allowing the cells to form microcolonies. These microcolonies combine into larger colonies that form the pearl.

SM1 Euryarchaeon cannot be grown in the lab, but there has been a system of polyethylene nets that have been developed in which they can harvest the bacteria. With these nets, scientists have discovered that in the sub-surfaces of the streamlets, the archaeon forms a biofilm, and SM1 Euryarchaeon is the first archaean to be a naturally-occurring monospecies in a biofilm. In the biofilm, the archaeon doesn’t need a bacterial partner like it does in the string-of-pearls formation.

There is still a lot of unknown information about this microbe. SM1 Euryarchaeon is relatively new and is uncultivable, making it hard to research. In future
research, scientists hope to further investigate the mechanisms of the biofilm and the string-of-pearls formations and how they interrelate. Also, they hope to learn more about the hami, which are thought to play roles in the formation of the biofilm.

By Emma Sioringas

Image: Artwork from the University of Toronto Wenceslaus Hollar Digital Collection

Vibrio harveyi

Vibrio harveyi is a gram-negative bacterium that primarily lives in seawater. It appears as a curved rod shape and has the unique characteristic of being luminescent. It is believed that V. harveyi causes a phenomenon known as the Milky Sea effect. The Milky Sea effect is when large areas of seawater are filled with bioluminescent bacteria, which cause the ocean to glow. These effects have mainly been documented in the North Western Indian Ocean, as well as near Indonesia. Most of the pictures make the Milky Sea Effect appear white due to monochromatic photos. In 2005, a milky sea effect was observed to be approximately 15,400 km squared, which is comparable to the size of Connecticut.

By Leiah Smolley

Image: Dr. Steve Miller, Naval Research Lab