For example, the pyrimidine and purine-nucleoside phosphorylases which are important in the nucleoside salvage pathways are among the most identified proteins in mycoplasmal proteomics studies. In several studies, several COG categories exhibited low identification numbers among several mycoplasmas, including proteins involve in Signal transduction mechanisms, Defense mechanism, Cell envelope biogenesis, outer membrane and several Metabolism subcategories. This is likely due to the low-abundance of these proteins and the improvement in the sample preparation may help to increase the identification numbers. On the other hand, absence of proteins in several categories may also be due to the lack of AP24534 external stimulation from and interaction with the host cells, giving that certain proteins were not necessary during host-free cultivation. Especially in M. pneumoniae and M. mobile, where overall identification ratios are high, there are still a number of missing proteins in the subcategories of Transcription, Defense mechanism and General function prediction only along with no COG assignment. It is also possible that different biological pathways could be triggered under bacterial growth under host-free culture with rich medium. Like the other human pathogen M. penetrans, M. fermentans M64 also has a relatively large genome and proteome. Both species have a large number of identified proteins in Transcription, Intracellular trafficking,Axitinib secretion, and vesicular transport and proteins with unknown COG functions compared with other mycoplasmal genomes. In addition, they have similar ratios of identified proteins in most of categories, implying these two mycoplasmas may have similar adaption in environment. Our results provided a basic knowledge of M. fermentans proteins involved in the host-free cultivation. Further studies of this microorganism as well as other Mycoplasma species co-cultured with host cells are suggested. Genome replication is central to the propagation of all life. In DNA genomes, replication initiates by the designation of genome sequences as origins, where synthesis of a copy of the genetic material begins. Origin designation is a complex, tightly regulated process whose core mechanisms and machinery are conserved between eukaryotes and archaea. This reaction involves the formation of a pre-replication complex, which in eukaryotes comprises the Origin Recognition Complex, Cdc6, Cdt1 and the replicative MCM helicase; for reviews, see. ORC is frequently described as being composed of six subunits, named Orc1–6, in all eukaryotes that have been examined to date.