Microbial Competition in Aquatic Environment

By: Marco V. Munoz

Fig.1 Comparison between a fixed environment and control cultures (a) Sample of incubated microbes with additional iron granules used as electron donor. (b) Sample of incubated microbes in a control solution (no additional iron). (c) Sample of methane production after environment became sediment-free and iron was replaced by acetate solution.

One key element to preserve diversity in microorganisms of aquatic environments is by the interactions between species that benefit one or both organisms. Previous studies have proposed that acetate produced by acetogens can feed commensal acetoclastic methanogens. However, a recent study carried out by Palacios and colleagues demonstrated that corrosive microbial communities (MIC) such as methanogens and acetogens found in low-sulfide environments in the sea, compete with each other rather than cooperate under the presence of electrons from metals such as iron (Fe0). The researchers collected sediment cores samples from Bothnian Bay, Baltic Sea at a water depth of 15 m. All cultures made from collected samples were tested and examined over a time frame. The analysis identified Sporomusa and Methanosarcina dominated the corrosive microbial communities found in samples based on taxonomy and the number of microbes observed. Microbial cultures with the addition of iron granules demonstrated a much higher production of methane and acetate compared to control cultures and decreased in number of Sporomusa was based on methane production being higher than acetate; Also, acetoclastic methanogens were observed being inactivated after the environment became sediment-free and iron was substituted by acetate solution (Figure 1). This concluded independency and competition for electrons between these two species existing in the same habitat. This is important to understand because microbial induced corrosion accounts for 20% damage to industries which affects the economy and also contributes to water contamination that leads to health and environment issues affecting other living organisms.

Original Article

Palacios PA, Snoeyenbos-West O, Löscher CR, Thamdrup B, and Rotaru AE. (2019). Baltic Sea Methanogens Compete with Acetogens for Electrons from Metallic Iron. The Isme Journal. doi:10.1038/s41396-019-0490-0.

Microbes Take Flight.

Airplanes are the safest way to travel for both people and microbes. Air travel can serve as a conduit for infectious disease spread, these infections include influenza, measles, norovirus, cholera, shigellosis, and tuberculosis.  The way that the bacterial communities are derived from is by the human skin, oral commensals, and the environment. A very important factor in disease transmission is the movements of crew and passengers. During a recent research study to see what kind microbiomes could be found within an air cabin, it was identified that there was no meaningful difference between air and touch surface microbial diversity measures, the systematic patterns stayed the same for pre and post flights. Air cabin OTU signatures for air microbiome were there, but there were not that much for individual touch surface type microbiomes. The indicated reason behind the difference in microbiomes is that each flight start and end with a different surface cleaning routines. The vast majority of airplane microbes are human commensals or non-pathogenic and luckily it was proven to be true. Microbes are already very intimidating having them travel around the world can be freighting just imagine one of them being extremely pathogenic on a flight. Remember Ebola?

 Air and touch surface microbial diversity measures and systematic patterns. 

Original Article: 

Weiss, H., Hertzberg, V.S., Dupont, C. et al. Microb Ecol (2019) 77: 87. https://doi-org.tamiu.idm.oclc.org/10.1007/s00248-018-1191-3

Kiwi, Lock and Loaded

Author: Amanda Ponce

     Kiwellin is a protein isolate from kiwi (Actinidia chinensis) fruit and can also be found in most plant species. Zea Mays or maize carries a kiwellin protein that is versatile in defense mechanisms against fungal diseases. Maize is a domesticated crop that originated in the Americas that is distributed for food, feed livestock, used for biofuel, and is used as raw material. (Augistyn, A., Bauer, P., Duignan, B., Eldridge, A., Gregersen, E., McKenna, A., et al.) This article is centralized on Maize smut disease caused by the biotrophic fungus Ustilago maydis. There is an interaction between the fungal hyphae and an intruding cavity into the plant plasma membrane. Here, U. maydis secretes its effector proteins causing induced tumors. Cmu1 is a deregulated metabolic enzyme that is highly expressed during colonization of the plant and through biotrophic development. It is the conversion of chorismate to prephenate. Cmu1 is translocated to the cytosol, fluid in the plant membrane, and prevents the biosynthesis of salicylic acid that would mediate in plant immune responses against pathogens. Cmu1 has a crystal structure, and like the model organism Aro7p of Saccharomyces cerevisiae,  the both form a homodimer. A homodimer are two monomers that each have 9 α-helices and identical active sites. (Han, X., Altegoer, F., Steinchen, W., Binnebesel, L., Schuhmacher, J., Glatter, T., Giammarinaro, Pietro, I. et al 2019) Cmu1 is highly differentiated to Aro7p and other housekeeping enzymes in a region for allosteric regulation. This is activated and repressed by tryptophan and tyrosine because they biosynthesize proteins. In Aro7-, the binding site is made by the housekeeping genes, the α2 helix, and the adjacent loop for the amino acids tryptophan and tyrosine. Cmu1 however, has an addition α helix and an extensive loop region (ELR) that follow α2 helix and wrap around the structure. Basically, there is an absence of allosteric regulation by tryptophan and tyrosine in Cmu1.

Figure 1 shows a decrease in chorismate mutase activity of Cmu1 but not of Aro7p was led by an increase of concentration in ZmKWL1. Chorismate mutase was at 100% in the absence of ZmKWL1.

(Han, X., Altegoer, F., Steinchen, W., Binnebesel, L., Schuhmacher, J., Glatter, T., Giammarinaro, Pietro, I. et al 2019)

    

     What is interesting about the kiwellin protein is its versatile defense because of substrate binding block by altered ELR , the disabling of Cmu1 transport to the cytosol, and prohibiting the secretion of Cmu1. It is a paralogue gene meaning a derivative gene. Ultimately, there are more kiwellin proteins encoded that share the β barrel domain and disulfide bridge, permitting to target other fungal effectors.  This would not be eminently possible without model genetics. The models used in this investigation were to clone or model similar homodimer such Aro7p, the amino sequence in the hypothetical amino sequence of ZmKWL1, and genetic tagging used in the pull-down assays. Lastly, this article subjects the importance of environmental microbiology due to agricultural health hazards. A kiwellin protein variant can possibly be used to target other plant pathogens for safer and healthier uses.

Augistyn, A., Bauer, P., Duignan, B., Eldridge, A., Gregersen, E., McKenna, A., Petruzzello, M., Rafferty, J. P., Ray, M., Rogers, K., Tikkanen, A., Wallenfeldt, J., Zeidan, A., Zelazco, A., (2019 January 25) Corn. In Encyclopedia Britannica. Retrieved Octerber 23, 2019, from  https://www.britannica.com/plant/corn-plant.

Han, X., Altegoer, F., Steinchen, W., Binnebesel, L., Schuhmacher, J., Glatter, T., Giammarinaro, Pietro, I., Djamei, A., Rensing, S., Reissmann, S.,  Kahmann, R., Bange, G. A kiwellin disarms the metabolic activity of a secreted fungal virulence factor. Nature 2019; e-pub ahead of print 16 January 2019, doi: 10.1038/s41586-018-0857-9

Roaches and Bacteria! A match made in Heaven!

Periplaneta americana better known as the American cockroach is a pest found around the world. Most people dislike them and cringe at the mere sight of them. Well maybe except that one Japanese man (Yuta) who dated a cockroach (Lisa) for a year. That is a rare case though and most people don't like roaches much less date them. If anything they are uninvited guests in homes, hotels, restaurants and even hospitals. They are a nuisance and excellent mechanical vector, spreading bacteria in their wake. This is supported by a study done in Palu, Indonesia. Where roaches found in three hospitals were tested for the presence of bacteria. Astiti et al (2018), found that the roaches were harboring the following bacteria. Escherichia coli, Salmonella arizonae, Salmonella sp, Klebsiella ozaenae, Salmonella simultaneous and Salmonella choleraesuis. All of the previously mentioned bacteria were tested and were found to be resistant to amoxicillin. Salmonella choleraesuis, Klebsiella ozaenae, and Escherichia coli were also found to be resistant to chloramphenicol. This is significant because these antibiotics are often the treatment of choice in Palu, Indonesia. This is just another reason to dislike roaches.

Table 1: Shows the 6 types of bacteria present in the roaches found at the hospital.

Original article: Astiti, P. M. A., Bialangi, M., & Kundera, I. N. (2018). Identification of bacteria on Cockroach feet from Hospital area in Palu city and test of sensitivity to antibiotic. IOP Conference Series: Materials Science and Engineering, 434, 012123. doing: 10.1088/1757-899x/434/1/012123

LOOKS LIKE WHOLE FOODS AND TRADER JOES HAVE JUST ADDED A NEW AISLE…BACTERIA SECRETIONS! A NEW TREND? WE HAD A COUPLE QUESTIONS.

By: Alonso Trevino IV

The world of microorganisms has presented the world with many reasons to hate the tiny bacteria and it seems increasingly difficult to avoid them. Still, while we remain skeptical and quite a bit scared about the consequences of our interaction with these organisms of the environment, a new study suggests a completely new twist of fate. While the juicing and healthy meal prep’s frenzy around the world continues to flourish into a full on trend, it seems that our dietetic science friends have begun to find new ways in which to consume the tiny bacteria which we were once afraid of. In a new study that is calling these edible treats, functional foods, “Postbiotics refers to soluble factors (products or metabolic byproducts), secreted by live bacteria, or released after bacterial lysis, such as enzymes, peptides, teichoic acids, peptidoglycan-derived muropeptides, polysaccharides, cell surface proteins, and organic acids” while this concept presents a very controversial reality, it represents a very viable reality nonetheless. This is mainly reassured by the fact that not only do these bacteria excretions create foods with longer shelf lives but they, “may have anti-inflammatory, immunomodulatory, anti-obesogenic, antihypertensive, hypocholesterolemic, anti-proliferative, and antioxidant activities.” (Toala 2018) The presence of these probiotics, prebiotics and postbiotics in popular foods like yogurt have baffled many but more importantly allowed scientists and doctors alike find new ways to incorporate microorganism into functioning human medicines. Will this new use of bacteria allocation be the hipster trend of the 2010’s or will it prove to be a crucial source of health beneficial functioning foods of the future?

Figure 1. In the image above, an abstract view of the essential health benefits of these bacterial friendly foods is depicted.

Original Article:

Aguilar-Toalá, J. E., Garcia-Varela, R., Garcia, H. S., Mata-Haro, V., González-Córdova, A. F., Vallejo-Cordoba, B., & Hernández-Mendoza, A. (2018). Postbiotics: An evolving term within the functional foods field. Trends in Food Science & Technology, 75, 105-114.