Take a moment and think about how you might be creating waste products. Do you think of food scraps, un-recycled plastic, or exhaust from your car? True, those are valid sources of human-made waste. But have you ever considered the caffeine from your coffee, the ibuprofen you use for aches and pains, or the preservatives in lotion and makeup as a form of potentially harmful waste? These chemical contaminants often go unnoticed, washed down sinks or discarded in trash. However, there is growing evidence that chemicals from Pharmaceuticals and Personal Care Products (abbreviated as PPCPs) can create harmful impacts on our environment (Onesios, Yu, & Bouwer 2008).
Prospects for Fungal Bioremediation of Acidic Radioactive Waste Sites: Characterization and Genome Sequence of Rhodotorula taiwanensis MD1149
“Highly concentrated radionuclide waste produced during the Cold War era is stored at US Department of Energy (DOE) production sites. This radioactive waste was often highly acidic and mixed with heavy metals, and has been leaking into the environment since the 1950s. Because of the danger and expense of cleanup of such radioactive sites by physicochemical processes, in situbioremediation methods are being developed for cleanup of contaminated ground and groundwater. To date, the most developed microbial treatment proposed for high-level radioactive sites employs the radiation-resistant bacterium Deinococcus radiodurans. However, the use of Deinococcus spp. and other bacteria is limited by their sensitivity to low pH. We report the characterization of 27 diverse environmental yeasts for their resistance to ionizing radiation (chronic and acute), heavy metals, pH minima, temperature maxima and optima, and their ability to form biofilms. Remarkably, many yeasts are extremely resistant to ionizing radiation and heavy metals. They also excrete carboxylic acids and are exceptionally tolerant to low pH. A special focus is placed on Rhodotorula taiwanensis MD1149, which was the most resistant to acid and gamma radiation. MD1149 is capable of growing under 66 Gy/h at pH 2.3 and in the presence of high concentrations of mercury and chromium compounds, and forming biofilms under high-level chronic radiation and low pH. We present the whole genome sequence and annotation of R. taiwanensis strain MD1149, with a comparison to other Rhodotorula species. This survey elevates yeasts to the frontier of biology’s most radiation-resistant representatives, presenting a strong rationale for a role of fungi in bioremediation of acidic radioactive waste sites.”
Tkavc Rok, Matrosova Vera Y., Grichenko Olga E., GostinÄar Cene, Volpe Robert P., Klimenkova Polina, Gaidamakova Elena K., Zhou Carol E., Stewart Benjamin J., Lyman Mathew G., Malfatti Stephanie A., Rubinfeld Bonnee, Courtot Melanie, Singh Jatinder, Dalgard Clifton L., Hamilton Theron, Frey Kenneth G., Gunde-Cimerman Nina, Dugan Lawrence, Daly Michael J. (2018). Prospects for Fungal Bioremediation of Acidic Radioactive Waste Sites: Characterization and Genome Sequence of Rhodotorula taiwanensis MD1149. Frontiers in Microbiology 8:2528.
I thought this paper would be interesting to look at not only because it deals with fungi, which are not often thought of as microbes, but because of why fungi were chosen. There are distinctive advantages and disadvantages to utilizing different types of microbes in bioremediation, and I think this paper addresses that well. There is also a definite need for something which is able to process the contamination at this site, and bioremediation is an intriguing possibility.
Hugues, T., et al. (2018). Influence of environmental changes on the biogeochemistry of arsenic in a soil polluted by the destruction of chemical weapons: A mesocosm study. Science of the Total Environment. 627. 216-226.
“Thermal destruction of chemical munitions from World War I led to the formation of a heavily contaminated residue that contains an unexpected mineral association in which a microbial As transformation has been observed. A mesocosm study was conducted to assess the impact of water saturation episodes and input of bioavailable organic matter (OM) on pollutant behavior in relation to biogeochemical parameters. Over a period of about eight (8) months, the contaminated soil was subjected to cycles of dry and wet periods corresponding to water table level variations. After the first four (4) months, fragmented litter from the nearby forest was placed on top of the soil. The mesocosm solid phase was sampled by three rounds of coring: at the beginning of the experiment, after four (4) months (before the addition of OM), and at the end of the experiment. Scanning electron microscopy coupled to energy dispersive X-ray spectroscopy observations showed that an amorphous phase, which was the primary carrier of As, Zn, and Cu, was unstable under water-saturated conditions and released a portion of the contaminants in solution. Precipitation of a lead arsenate chloride mineral, mimetite, in soils within the water saturated level caused the immobilization of As and Pb. Mimetite is a durable trap because of its large stability domain; however, this precipitation was limited by a low Pb concentration inducing that high amounts of As remained in solution. The addition of forest litter modified the quantities and qualities of soil OM. Microbial As transformation was affected by the addition of OM, which increased the concentration of both As(III)-oxidizing and As(V)-reducing microorganisms. The addition of OM negatively impacted the As(III) oxidizing rate, however As(III) oxidation was still the dominant reaction in accordance with the formation of arsenate-bearing minerals.”
I believe it is extremely important to investigate means of repairing the damage we bring about to the ecosystem, especially in the wake of wars or other destructive events. This paper looks at how we can utilize the knowledge and tools at our disposal to help reduce the total amount of contamination in soils by encouraging microbial activity.
A look into the microbial ecosystems associated with humans and our home environments.
Collaborators: Connor Ito, Zachary Snelson, Alisa Thiede, and Kirsten Veech
Do you think of your body as a habitat? Have you ever considered the multitudes of microscopic organisms that colonize your skin? Most of us don’t, but the truth is that you are a teeming ecosystem of bacteria and other microbes. Even more, each person has a distinctive ‘fingerprint’ associated with their own unique microbiome, or the ecosystem found on their person.
However, you also impact the environment you occupy; your house is covered in your own microbes, and so is anyone else who lives with you- even your pets. In fact, you’re also covered in their bacteria. Entire families can be linked by the microbial communities found on their skin, and their houses associated by finding the same communities on inanimate objects. About 77% of the time, a person’s bacterial signature can be matched to their house accurately!
A person’s individual microbial signature is most distinct within the nose and least on the hands. On average, about a third of a person’s skin microbiome is the same as that of surfaces within their house, though this can rise or fall depending on the individuals and areas sampled. Merely by existing in a space, you spread your own microbial fingerprint. Conversely, the longer you are away from an area, the weaker this fingerprint is on an area.
Of course, the big question- can any of the bacteria in my house hurt me? This study found that your hands actually have the highest chance of carrying microbes that can make you sick, and that’s because your hands touch the most surfaces in your house. Countertops were found to have more potentially harmful types of bacteria than any other surface in a house.
Knowing this, scientists can apply knowledge of microbes to assess the spread of disease, individual health, and the impact of humans on bacterial diversity. Since an increasing number of people are spending time indoors and at home, understanding the spread of bacteria in the context of health in our homes and how our actions serve to spread our signature to our environment and to others.
Recent investigations into the microbial communities in human-made environments have revealed the composition of such environments to be directly linked to the occupants of each space, human and animal alike. Utilizing 16S rRNA amplicon sequencing, the microbial communities from numerous surfaces within homes and on human occupants were characterized and compared to identify patterns.
In this study, 1625 samples yielded 21,997 OTUs over a 4-6 week period. Several of the families moved during the period of the study; when this occurred, samples were obtained from both the old and new spaces. Analysis of similarities (ANOSIM) differentiation was used to compare differences between surfaces, humans, and pets within and between the homes studied.
Within each study area, humans were the greatest contributors to bacteria found on surfaces. Actinobacteria and Proteobacteria, two major components of human skin flora, dominated such samples. Between humans, the soles of the feet were found to contain the most unique OTUs, while the palms of the hands were least distinct.
It was found that a person’s skin sample could be matched to commonly accessed surfaces within their house 76.7% of the time, demonstrating not only that microbial communities in homes are significantly more similar to those of their occupants, but that colonization can occur rapidly. Additionally, the longer an occupant was not within the area, the less their own microbial signature could be detected in samples. This may indicate rapid turnover of bacteria or demonstrate how significant the contribution of microbial transfer from skin to surfaces is within a space.
The study also looked briefly into microbes with pathogen potential by utilizing shallow shotgun metagenomic sequencing. Corynebacterium was found on all humans, with Enhydrobacter-, Streptococcus-, and Enterobacter-like bacteria found on surfaces around the house, especially on countertops. Close matches for Pantoea agglomerans and Acinetobacter baumannii were also observed in kitchen samples. Hand samples were found to have the greatest potential for pathogenic bacteria, sharing the greatest similarity with countertops.
Better understanding the impact of humans upon the microbiome in environment they occupy and how these microbes are distributed and spread is a crucial and understudied facet of human health. This study works to look into the origins and patterns of such communities, with intriguing discoveries with applications in healthcare and microbial analysis.
Want to read it? Click HERE.
“Snowmelt in the Antarctic Peninsula region has increased significantly in recent decades, leading to greater liquid water availability across a more expansive area. As a consequence, changes in the biological activity within wet Antarctic snow require consideration if we are to better understand terrestrial carbon cycling on Earth’s coldest continent. This paper therefore examines the relationship between microbial communities and the chemical and physical environment of wet snow habitats on Livingston Island of the maritime Antarctic. In so doing, we reveal a strong reduction in bacterial diversity and autotrophic biomass within a short (<1 km) distance from the coast. Coastal snowpacks, fertilized by greater amounts of nutrients from rock debris and marine fauna, develop obvious, pigmented snow algal communities that control the absorption of visible light to a far greater extent than with the inland glacial snowpacks. Absorption by carotenoid pigments is most influential at the surface, while chlorophyll is most influential beneath it. The coastal snowpacks also indicate higher concentrations of dissolved inorganic carbon and CO2 in interstitial air, as well as a close relationship between chlorophyll and dissolved organic carbon (DOC). As a consequence, the DOC resource available in coastal snow can support a more diverse bacterial community that includes microorganisms from a range of nearby terrestrial and marine habitats. Therefore, since further expansion of the melt zone will influence glacial snowpacks more than coastal ones, care must be taken when considering the types of communities that may be expected to evolve there.”
2017), Microbes influence the biogeochemical and optical properties of maritime Antarctic snow, J. Geophys. Res. Biogeosci., 122, 1456—1470., , , , , , , and (
I selected this paper as a means to expand what could be considered as an environment while also wanting to learn more about how changes to the global climate might affect different microbial communities, especially in areas expected to undergo notable change.
I wouldn’t think of travelling to Antarctica to study microbial life, yet this paper explores the communities found there and how a warming climate is affecting both carbon emissions and microbial diversity on what most would consider a barren waste. I found it especially fascinating that microbial activity may actually enhance the melt of Antarctic ice!
Hey! My name is Connor Ito, I’m a general biology major (though my primary interests are physiology and wildlife). I have also pursued a minor in Art, mainly in two-dimensional media. I’m an undergraduate student who has dabbled in a little bit of everything that has interested me here at UAF, from theater and film to labwork and independent research.
I love the integration of linear and creative thinking employed in Dr. Leigh’s classes, and hoped to see more in this class! Looking forward to spending the upcoming semester with you all!
Glass of the ice lake-
Frozen within, breaths of fire
I have no recent pictures on my new laptop, so this will have to do!