Wednesday, 6 May 2015

Archaea kind of day

It was archaea group's turn to present. Here, attached the mind map done by archaea group.



So, there are 4 categories based on its cell wall ---- Gram -ve bacteria + cell wall, Gram +ve bacteria + cell wall, Bacteria lacking cell wall and the archaebacteria. 

The extreme habitats for archaea are cold and hot environments, high salinity and anaerobic environments. 

The unique features of archaea are the cell wall, membrane lipids, metabolism and genetics.

Special cell wall for Methanogens-- the benefits are: methane--> clean burning fuel--> energy for heat and electricity. Crenarcheota is the only known archaea with outer membrane.

Metabolism -- use many sources of energy --- phototrophs, lithotrophs, organotrophs.    

We also did some SCL questions, which Dr Wan asked us to find the answer by searching some related journals. For my group, the question was  explain the adaptation of archaea to withstand acidic conditions. Well, I couldn't recall the padlet page, so I will just explain how archaea withstand acidic conditions, based on the journal.

cidophilic enzymes have optimal structure and stability in acidic environments and have been shown to be catalytically active at pHs as low as 1. Most known acidophiles are also thermophiles, and hence their proteins reflect thermophilic features. Interestingly, the adaptation of acidophilic proteins to pH is unclear and inconsistent.

Acidophilic proteins must adapt to the low pH because acid interferes with the charge on many residues. At low pH many polar charged residues become protonated and, therefore, their charges change. This has the possibility of disrupting stabilizing structural interactions, unfolding the protein.

While the specific adaptation has not been explored in great detail, the activity of these proteins at low pH seems to be attributed to the prevalence of acidic (negatively charged at a neutral pH) amino acids on the surface of these enzymes and proteins.


That's all for this entry. Thank you!


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