In the sulfur cycle, microbes degrade organic sulfur compounds,such as _________ to release H2S, which can be oxidizedby Thiobacillus to _______________. This ion can beassimilated into amino acids by _____________ or reduced byDesulfovibrio to _______________. Hydrogen Sulfide(H2S) is used by photoautotrophic bacteria as anelectron donor to synthesize ______________. The sulfur-containingby-product of this metabolism is_______________.