User talk:Klm01011/Thiomargarita namibiensis

introduction
Thiomargarita namibiensis, known for its large size, has a special profile as an anaerobe, mesophile, and neutrophile. As an anaerobe, this bacterium thrives in low oxygen levels where it relies on anaerobic respiration for energy production. It is categorized as a mesophile because of its preference for moderate temperatures, which typically range between 20-45 degrees Celsius. The organism shows neutrophilic characteristics by favoring environments with neutral pH levels like 6.5-7.5. This highlights the bacterium's unique strategies to maintain its survival and grow.

discovery
section kinda confusing, doesn't elaborate much on mexico strain COR9 (talk) 20:10, 8 February 2024 (UTC)

significance to world: niche/purpose

It forms a film on the top of sulfidic sediments and detoxifies sulfide so that it can enter the water column.https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4914600/

The species Thiomargarita namibiensis was discovered in 1997 by Heide N. Schulz and her colleagues from the Max Planck Institute for Marine Microbiology. It was discovered in coastal sediments on the Namibian coast. Schulz and her colleagues were aboard the Russian research vessel Petr Kottsov in search of Thioploca, another recently discovered sulfide-eating marine bacteria when Schulz team found small quantities of Thioploca and Beggiatoa in sediment samples, but large quantities of the previously undiscovered Thiomargarita namibiensis.[5] Researchers suggested the species be named Thiomargariita namibiensis, which means sulfur pearl of Namibia. https://www.whoi.edu/press-room/news-release/giant-sulfur-bacteria-discovered-off-african-coast/

The Namibian coastal environmental experiences strong upwelling, resulting in low oxygen levels in the lower waters with large amounts of planton. Thiomargarita namibiensis is most prevalent in the Walvis Bay area at 300 feet deep. The highest number of Thiomargarita namibiensis is present in the sediment's uppermost three centimeters. Since the Thiomargarita namibiensis are immobile, they are unable to seek more a more ideal environment when sulfide and nitrate levels are low in this environment. They simply remain in position and wait for levels to increase once again so that they can undergo respiration and other processes. https://www.whoi.edu/press-room/news-release/giant-sulfur-bacteria-discovered-off-african-coast/ — Preceding unsigned comment added by COR9 (talk • contribs) 15:24, 29 February 2024 (UTC)

metabolism
The sulfur bacterium, Thiomaragrita namibiensis, thrives in places with little oxygen such as in ocean bottoms. This categorizes the bacterium as using anaerobic respiration. In order to survive in such a harsh environment, Thiomargarita namibeiensis uses what is known as the reverse or reductive TCA cycle to convert CO2 into usable energy. This adaptation shows how the bacterium has learned to survive in specific environments where usual metabolic pathways might not work well enough.

structure
Although Thiomargarita are closely related to Thioploca and Beggiatoa in function, their structures are different. Thioploca and Beggiatoa cells are much smaller and grow tightly stacked on each other in long filaments. Their shape is necessary for them to shuttle down into the ocean sediments to find more sulfide and nitrate. In contrast, Thiomargarita grow in rows of separate single ball-shaped cells, so they lack the range of mobility that Thioploca and Beggiota have. Thiomargarita can also grow in barrel shapes. The spherical shaped Thiomargarita can join together to create chains of 4-20 cells, while the barrel shaped Thiomargarita can form chains of more than 50 cells. These chains are not linked together by filaments, but connected by a mucus sheath.

With their lack of movement, Thiomargarita have adapted by evolving very large nitrate-storing bubbles, called vacuoles, allowing them to survive long periods of nitrate and sulfide starvation. However, new studies have shown that although there are no present motility features, the individual spherical cells can move slightly in a “slow jerky rolling motion,”  but this does not give them free range motion as traditional motility features would. The vacuoles give them the ability to stay immobile, just waiting for nitrate-rich waters to sweep over them once again. These vacuoles are what account for the size that scientists had previously thought impossible, and account for roughly 98% of the cell volume. Because of the vast size of the liquid central vacuole, the cytoplasm separating the vacuole and the cell membrane is a very thin layer reported to be around 0.5-2 micrometers thick. This cytoplasm, however, is non-homogenous. The cytoplasm contains small bubbles of sulfur, polyphosphate, and glycogen. These bubbles gives the cytoplasm a “sponge-like” resemblance.

Scientists disregarded large bacteria, because bacteria rely on chemiosmosis and cellular transport processes across their membranes to make ATP. As the cell size increases, they make proportionately less ATP, thus energy production limits their size. Thiomargarita are an exception to this size constraint, as their cytoplasm forms along the periphery of the cell, while the nitrate-storing vacuoles occupy the center of the cell. As these vacuoles swell, they greatly contribute to the record sizes of Thiomargarita cells. T. namibiensis holds the record for the world's second largest bacteria, with a volume three million times more than that of the average bacteria.

Being that areas of nitrate and hydrogen sulfide do not mix together and T. namibiensis cells are immobile, the storage vacuoles in the cell provide a solution to this problem. Because of these storage vacuoles, cells are able to stay viable without growing (or dividing), with low relative amounts of cellular protein, and large amounts of nitrogen in the vacuoles. The storage vacuoles provide a novel solution which allows cells to wait for changing conditions while staying alive.

significance
Thiomargarita plays a vital role in the sulfur and nitrogen cycles. In their sulfur rich environment, oxygen is scarcely available and cannot be used as an electron acceptor. In turn, Thiomargarita uses nitrate as the electron acceptor, which they consume at the sediment surface and condense in a vacuole. From this, they can oxidize the sulfide that inhabits the sediment. This acts as a detoxifier which removes poisonous gas from the water. This keeps the environment affable for the fish and other marine living beings. This bacteria also plays an essential role in the phosphorus cycle of the sediment. Thiomargarita can release phosphate in anoxic sediments that possess high rates which contribute to the spontaneous precipitation of phosphorus-containing material. This plays an important role in the removal of phosphorus in the biosphere.

Schulz, H. N. (2006). The genus Thiomargarita. Prokaryotes, 6, 1156-1163.