Toxin-Synthesizing Bacteria in Contaminated Bodies of Wate

After billions of years of evolution, cyanobacteria are capable of thriving in extreme and changing environments. The problem, however, is that that these microorganisms inhabit many areas where humans may potentially be exposed to them. Such areas include but are not limited to marine, freshwater, and terrestrial habitats. Research on risk assessment of contaminated water bodies is always ongoing in order to determine which kind of environments favor toxin production in these cyanobacteria. Hence, the genetic basis for toxin production in cyanobacteria has been identified and is used in continuing research for contaminated bodies of water. These discoveries are crucial for determining the environmental factors that influence toxin production and thus affect water quality.

Figure from Neilan et al (2013) Structure of one kind of cyanobacteria.

Neilan, Brett A. et al. Environmental conditions that influence toxin biosynthesis in cyanobacteria. Enviro Microbiol 2013; e-pub ahead of print 20 March 2013, DOI: 10.1111/j.1462-2920.2012.02729.x

Conan the Bacterium

By: Brenda Gonzalez

If you had to name the most epic, mindboggling bacteria in the world, Deinococcus radiodurans would come to mind. D. radiodurans is the most DNA damage-tolerant organism ever discovered. It's able to survive 2,000 to 6,666 times the gamma radiation that would kill a human and 250 to 5,000 times the UV radiation we use to kill microbes in our water supply. Luckily, it has no pathogenic qualities nor interacts with any other organism as far as scientists know. Armed with near immortality, this bacterium is currently being developed to treat radioactive waste. In the US, there are around 3,000 radioactive waste sites from nuclear weapon production; the estimated cost to clean them with current methods is $265 billion sparking an interest in research investigating cheaper alternatives. In the past 10 years, strains of D. radiodurans have been created with a gene cloned into them providing ionic mercury resistance. This allows them to not only flourish in these radioactive sites, but to grow on ionic mercury and detoxify it, helping remediate these waste sites. Recently, other researchers have engineered strains of these bacteria to express acid phosphatase, which allows the bioremediation of aqueous nuclear waste that results from reprocessing spent fuel rods (heavy in beta and gamma radiation), and another gene to precipitate uranium.

  

Original article: Chitra Seetharam Misra, Deepti Appukuttan,Venkata Siva Satyanarayana Kantamreddi, Amara S. Rao and Shree Kumar Apte. (2012). Recombinant D. radiodurans cells for bioremediation of heavy metals from acidic/neutral aqueous wastes. Landes Bioscience 44-48

Blame the skinny twin!

By: Melissa Saucedo
     There are little foreign invaders living in the human gut. A recent study involving identical twins that differ in weight (one lean and one obese) showed that when the fecal microbiota of each twin was injected into the germ-free gut of different mice, the mice developed similar body types as the twin whose microbiota it received. At a molecular level, mice with the lean twin microbiota produced more short chain fatty acids that allowed it to stay thin. In contrast, the metabolism of bulky amino acids increased in mice with microbiota of the obese twin. Furthermore, it was found that when lean and obese mice lived in the same area, the obese mice reduced their production of fat due to transformation of their microbiota from environmental microbes received from the lean mice. These findings showed that perhaps having the correct microbes does not only help control body weight, but it can also transform the microbiota of other individuals.

Figure from Kunkel D. (2007) depicting b. vulgaris, a bacteria found at different levels in the guts of both mice.

Original Article: Ridaura VK, Faith JJ, Rey FE, Cheng J, Duncan AE, et al. (2013). Gut Microbiota from twins discordant for obesity modulate metabolism in mice. Science Journal 341.

Maybe it’s Not Our Fault That We’re Fat

By: Ariana Cervantes 

 

We often worry about how our bad diet and lack of exercise is what causes obesity. In Shanghai, researchers found that the bacteria Enterobacter which can be found in a person’s gut can be the cause of our troubles. Scientists gave obesity-resistant mice a high caloric diet, but the mice did not gain weight until they were injected with Enterobacter from an obese human volunteer’s gut. Based on these results scientists were able to create a diet which reduced the Enterobacter population in their gut. This could potentially lead to the development of a diet that can help control obesity.

 

Figure from Fei et al (2013) comparing the effect on the mice’s body once injected with Enterobacter

Original Article: Fei N, and Zhao L. (2013). An opportunistic pathogen isolated from the gut of obese human cause obesity in germfree mice. ISME J 7:880-884.