User talk:Rehanna Thobani/sandbox

Assignment 1: Critique of the Chlorosome Article

Overall, the content of the article pertained to the subject and no information was unnecessary or irrelevant. Within the content, a neutral point of view was maintained and contributions by citations appeared to be unbiased in their research. Though the content was concise nature, the page was missing appropriate citations for all sections. Wikipedia suggests one citation per important point or paragraph, whereas this article lacked any citations under the headings “Structure” or “Alternative Energy Source”, thus reducing the credibility of the content. This article was also heavily based on very few sources, considering there are only four referenced under “Notes” and the "Organization of the light harvesting pigments" section was heavily based on only one study performed. The training module on Wikipedia strictly warns against relying on one source, so to improve the quality of this article, more studies or sources should be referenced. In the talk page, other studies are noted to have been done and alternative models of the structure are discussed, so the article should reflect these other available sources. In addition, other related studies should be referenced, particularly since the most recent study referenced was from 2007. Despite the lack of quantity in references, the quality was exceptional as there were credible research articles with in depth content on the subject. The credibility of resources is an element noted by Wikipedia that shows superior quality in a Wiki page, therefore this article had an adequate balance in good qualities and areas of improvement.

Reflection: It wasn't too difficult to critique the article and identify flaws and good qualities as the Wiki tutorial made it very clear of what to look for. One very important thing I learned was how important it is to check the references and citations at the bottom and to go through the talk page before considering a Wiki page credible as many people have the opportunity to input information and without citations or proper sources the information may be misleading.

Rehanna Thobani (talk) 06:25, 17 September 2017 (UTC)

Assignment 2: Critique of Haloarchaea Article

Despite not being a high priority on Wikipedia, haloarchaea is a particularly notable topic as shown by thousands of resources published on both the online UBC library database as well as thousands more on Google Scholar. Haloarchaea have been published in journals like “Extremophiles” and “BioMed Central” on numerous occasions, showing that there is research going on in many subtopics of the haloarchaea domain. They have even been recognized as a model organism in high salt environments with genomes of several strains sequenced. They are apparent in many locations world-wide and have had quite a lot of study around them as extremophiles. The notability of haloarchaea is more than sufficient to deserve greater coverage.

This article is excessively undeveloped when taking in to consideration the vast amount of content known on the topic, which is likely because it is ranked as low importance in the Wikipedia community. There are very few sections in this article which are only briefly explained pertaining to their environment, shape and phototrophy, so this article requires expansion to accurately reflect the research available to the public. The article adequately describes the environment in which these microbes live, but fails to address any reasons as to how they have adapted to these environments. Upon editing, introduction of the mechanisms that allow for their survival should be explained, for example, debriefing their salt-in method of managing osmotic pressure as well as mentioning specific proteins expressed to aid them in harsh environments. These are both key aspects demonstrating in interaction between the environment and the organisms and can be discussed in more detail. Also, this article lacks mention of molecules and nutrients within this environment that are available and can be utilized by the haloarchaea. Glycerol metabolism is one nutrient that should be used to give insight on nutrient cycling and availability within this environment to demonstrate their metabolic adaptations to the environment.

Rehanna Thobani (talk) 00:50, 28 September 2017 (UTC)

Living environment

Salt ponds with pink colored Haloarchaea

Haloarchaea require salt concentrations in excess of 2 M (or about 10%) to grow, and optimal growth usually occurs at much higher concentrations, typically 20–25%. However, Haloarchaea can grow up to saturation (about 37% salts).

Haloarchaea are found mainly in hypersaline lakes and solar salterns. Their high densities in the water often lead to pink or red colourations of the water (the cells possessing high levels of carotenoid pigments, presumably for UV protection).

Adaptations to Environment

Salt ponds with pink colored Haloarchaea

Haloarchaea are found mainly in hypersaline lakes and solar salterns. Their high densities in the water often lead to pink or red colourations of the water as the cells possessing high levels of carotenoid pigments, presumably for UV protection .

Haloarchaea require a salt concentration of more than 2 M (or about 10%) to grow, and optimal growth usually occurs at much higher concentrations, typically 20–25%. However, Haloarchaea can grow up to saturated salt concentrations, which corresponds to about 37% salts. Most microorganisms can’t multiply with when the water activity (a_w) is lower than 0.90, yet in the environments of saturated salt, a_w is close to 0.75, which is inhibitory to the growth of most microbes . The number of solutes also causes osmotic stress on microbes, which can cause cell lysis, unfolding of proteins and inactivation of enzymes when there is a large enough imbalance. Haloarchaea have evolved mechanisms to evade these environmental obstacles.

One strategy haloarchaea use to allow them to thrive in the conditions of low a_w and high osmotic pressure is to retain compatible solutes in their intracellular space. A common compatible solute used by haloarchaea is potassium chloride (KCl), referred to as the “salt-in” method, where the cell accumulates a high internal concentration of potassium. Because of the elevated potassium levels, haloarchaea have specialized proteins which have a highly negative surface charge to tolerate high potassium concentrations..

Haloarchaea use glycerol as an important carbon and energy source and it is often present in high salt environments due to another organism, Dunaliella, which is a eukaryotic microalga that produces large amounts of glycerol as a compatible solute. Haloarchaea do not use glycerol as a compatible solute, but many break down glycerol in catabolism.

Rehanna Thobani (talk) 00:12, 7 October 2017 (UTC)

Adria Lwin's Peer Review

The author has chosen to expand on a section titled “Living environment” in the original article on haloarchaea by explaining how they are adapted to their environments. The edited section is written in a neutral tone and is generally well structured and easy to follow. It is commendable how Rehanna has included hyperlinks to relevant articles which support her ideas and allow interested readers to follow up on certain topics without bogging down the article with too much detail. Overall the edits contribute depth to the article.

There are a few areas where the writing could be improved. The information could be conveyed in fewer words without sacrificing clarity. The first paragraph is a fragment of an existing one; it is unnecessary and could be condensed into the first few sentences of the second paragraph. In addition, opening with the high salt requirements of haloarchea would make more sense as it is the main idea of this section while the fact that they turn water red is merely interesting supplemental information. The remainder of the paragraph could also be written more concisely.

Rehanna uses a wide variety of reliable sources to justify her statements, without relying too much on a single source. It is however unclear where the numerical figures cited under an article by Yadav et. al originate as I was unable to locate them in that article. Furthermore, there are several duplicate sources in the Notes section.

Finally, it is unclear how the last paragraph relates to the main idea as it does not, to the best of my understanding, explain how haloarchaea are adapted to their extreme environments. This paragraph should be placed under a different section entirely, or perhaps more explanation is required to elucidate its relevance to the rest of the section. Adria Lwin (talk) 06:58, 9 November 2017 (UTC)

Adaptations to the Environment

Salt ponds with pink colored Haloarchaea

Haloarchaea are found mainly in hypersaline lakes and solar salterns. Their high densities in the water often lead to pink or red colourations of the water as the cells possessing high levels of carotenoid pigments, presumably for UV protection. Haloarchaea require a salt concentration of more than 2 M (about 10%) to grow, and optimal growth usually occurs at much higher concentrations, typically 20–25%, though they can grow up to saturated salt concentrations (37%). A water activity (a_w) lower than 0.90 is inhibitory to most microbes, yet haloarchaea can grow at an a_w close to 0.75. The number of solutes causes osmotic stress on microbes, which can cause cell lysis, unfolding of proteins and inactivation of enzymes when there is a large enough imbalance. Haloarchaea combat this by retaining compatible solutes such as potassium chloride (KCl) in their intracellular space to allow them to balance osmotic pressure. Retaining these salts is referred to as the “salt-in” method where the cell accumulates a high internal concentration of potassium. Because of the elevated potassium levels, haloarchaea have specialized proteins which have a highly negative surface charge to tolerate high potassium concentrations.

Haloarchaea have adapted to use glycerol as a carbon and energy source in catabolic processes, which is often present in high salt environments due to Dunaliella species that produce glycerol in large quantities.

Rehanna Thobani (talk) 06:05, 20 November 2017 (UTC)