Supplementary Materialsmicroorganisms-07-00617-s001. Gram-negative, obligate intracellular bacterias sharing a unique biphasic developmental cycle. Chlamydial division has been a mystery for a long time due to its minimal division machinery, which lacks several division proteins that are essential in other bacteria. This reduced division machinery is conserved among members of the order, both in the well-described family and as in family includes several well-known human pathogens, such as is a strict human pathogen which is the leading bacterial cause of sexually transmitted infections [2] and the causative agent of trachoma, an eye infection that can RGS16 lead to blindness [3]. and infections can lead to respiratory tract infections in humans, O-Phospho-L-serine such as pneumonia [4], bronchitis [5], and psittacosis, respectively [6]. The family, is suspected to play a role in abortion in ruminants [7,8,9] and miscarriage in humans [2,10,11]. Furthermore, the presence of is associated with lower respiratory tract infections. Indeed, DNA was detected in nasopharyngeal samples from children with bronchitis [12] and in respiratory examples from individuals with pneumonia [13]. The chlamydial biphasic developmental routine is conserved among the order. It is characterized by two different bacterial morphologies: infectious nondividing elementary bodies (EBs) and noninfectious dividing reticulate bodies (RBs) [14,15]. EBs enter the host cell by phagocytosis or endocytosis, thus being first engulfed in an endosome vesicle, which, after several modifications induced by the bacterium itself, becomes an inclusion. Typically, recruits mitochondria around its inclusion within three hours post-infection and escapes the endocytic pathway by maturing the inclusion in a vacuole expressing endoplasmic reticulum proteins, such as calnexin [16]. After several cycles of replication, RBs redifferentiate into EBs and leave the host cell through exocytosis or cell lysis [15]. Under certain conditions, can enter a persistent nondividing, noninfectious stage called aberrant bodies (ABs). Diverse stimuli can induce the formation of aberrant bodies: addition of ?-lactam antibiotics such as penicillin, clavulanic acid [17], phosphomycin [18], iron or nutrient starvation [19], IFN-gamma treatment [19], and co-infection of the host with herpes or other viruses [20]. In order to better describe the chlamydial division mechanism, was used as a model organism. Several reasons make a convenient model for this study. First of all, can infect and proliferate in O-Phospho-L-serine a wide range of host cells, such as Vero cells, amoebae, human macrophages, pneumocytes, endometrial cells, insect cells, and fish cell lines [21,22,23]. Furthermore, was shown to exhibit a large genome, which makes it interesting for the development of genetic tools and studying evolution [24]. Next, cells are larger in size, making them eligible for microscopic observations, especially for tracking protein localization during chlamydial division. Last but not least, unlike has been shown to be sensitive to phosphomycin, which targets the very first step of peptidoglycan (PG) biosynthesis [25]. PG is an essential component O-Phospho-L-serine of the bacterial cell wall and is composed of a chain of alternating molecules called N-acetylglucosamine (GlcNAc) and N-acetylmuramic acid (MurNAc) residues that are cross-linked by short peptides made of L- and D-amino acids. PG maintains the bacterial shape, protects bacteria from environmental stress, provides them with a structural power, and is involved with bacterial department [26]. People from the purchase had been considered to absence PG, whereas recent research detected PG in a number of people of and [27,28,29]. have a very minimal department machinery, because they absence the primary organizer of bacterial department FtsZ and many additional department septum protein. FtsZ can be a tubulin homologue and the primary organizer from the cytokinetic system in nearly all prokaryotic cells. The primary function of FtsZ can be to assemble a well balanced but powerful cytokinetic band (Z band) at the near future site of department also to recruit additional the different parts of the department equipment (the divisome) [30]. Therefore, the primary function from the divisome parts in may be the modification and synthesis of PG [26]. Apparently, in the absence of an FtsZ homologue, still divide by binary fission [24,31]. Presumably, in the tubulin FtsZ has been replaced by the actin homologue MreB, which borders the cytoplasmic membrane and is involved in PG synthesis during elongation of rod-shaped bacteria [32,33,34]. Recent studies proposed that relies on rod-shaped determining proteins Pbp2 and MreB for cell division [35]. Indeed, application of MreB inhibitors could arrest division and induce formation of aberrant bodies [35]. The actin homologue MreB was also shown to define the predicted septal plane during chlamydial division in [36]. Moreover, recent studies have also demonstrated that relies on the actin homologue MreB and its regulator, RodZ, for division [18]. Interestingly, MreB was detected at the division septum O-Phospho-L-serine during middle and late division stages, whereas its regulator, RodZ, was shown to be an early recruit [18]. Another septal protein.