Structural insights into the mechanism of archaellar rotational switching

Signal transduction via phosphorylated CheY towards the flagellum and the archaellum involves a conserved mechanism of CheY phosphorylation and subsequent conformational changes within CheY. This mechanism is conserved among bacteria and archaea, despite substantial differences in the composition and architecture of archaellum and flagellum, respectively. Phosphorylated CheY has higher affinity towards the bacterial C-ring and its binding leads to conformational changes in the flagellar motor and subsequent rotational switching of the flagellum. In archaea, the adaptor protein CheF resides at the cytoplasmic face of the archaeal C-ring formed by the proteins ArlCDE and interacts with phosphorylated CheY. While the mechanism of CheY binding to the C-ring is well-studied in bacteria, the role of CheF in archaea remains enigmatic and mechanistic insights are absent. Here, we have determined the atomic structures of CheF alone and in complex with activated CheY by X-ray crystallography. CheF forms an elongated dimer with a twisted architecture. We show that CheY binds to the C-terminal tail domain of CheF leading to slight conformational changes within CheF. Our structural, biochemical and genetic analyses reveal the mechanistic basis for CheY binding to CheF and allow us to propose a model for rotational switching of the archaellum. Signal transduction via phosphorylated CheY is conserved in bacteria and archaea. In this study, the authors employ structural biochemistry combined with cell biology to delineate the mechanism of CheY recognition by the adaptor protein CheF

Transcriptional Regulation of the Capsular Polysaccharide Biosynthesis Locus of Streptococcus Pneumoniae: a Bioinformatic Analysis

The polysaccharide capsule of Streptococcus pneumoniae is the main virulence factor, which makes the bacterium resistant to phagocytosis. Expression of capsular polysaccharide must be adjusted at different stages of pneumococcal infection, thus, their transcriptional regulation appears to be crucial. To get insight into the existence of regulatory mechanisms common to most serotypes, a bioinformatic analysis of the DNA region located upstream of the capsular locus was performed. With the exception of serotype 37, the capsular locus is located between dexB and aliA on the pneumococcal chromosome. Up to 26 different sequence organizations were found among pneumococci synthesizing their capsule through a Wzy-polymerase-dependent mechanism, mostly varying according to the presence/absence of distinct insertion elements. As a consequence, only ∼250 bp (including a 107 bp RUP_A element) was conserved in 86 sequences, although only a short (ca. 87 bp) region located immediately upstream of cpsA was strictly conserved in all the sequences analyzed. An exhaustive search for possible operator sequences was done. Interestingly, although the promoter region of serotype 3 isolates completely differs from that of other serotypes, most of the proteins proposed to regulate transcription in serotype 3 pneumococci were also predicted to function as possible regulators in non-serotype 3 S. pneumoniae isolates

Project CAPTIVE e-manual - suggestions for an ‘ideal’ multicultural system to support migrant women victims-survivors of S-GBV

UNHCR data1 shows that we are currently witnessing the highest levels of displacement on record, with 68.5 million forcibly displaced people worldwide and 44,400 people forced to flee their homes each day because of conflict and persecution. Many of these people are internally displaced and are living in IDP camps in their countries of origin, others have travelled to neighbouring countries, and others still have journeyed to Europe. Among them is a rising number of women and girls, who are not only exposed to various forms of sexual and gender-based violence in their homelands, but also along the way and upon arrival in Europe. Their experiences of violence differ in many ways from those of local women; accordingly, the support offered by services in the host country should be tailored to the specific needs of this target group.Project reference CAPTIVE/Just/2015/ RDAP/AG/VICT/9243 C.A.P.T.I.V.E. Cultural Agent Promoting & Targeting Interventions vs Violence & Enslavement JUSTICE Programme – RIGHTS, EQUALITY and CITIZENSHIP – DAPHNE Strandpeer-reviewe

A Functional Genomics Approach to Establish the Complement of Carbohydrate Transporters in Streptococcus pneumoniae

The aerotolerant anaerobe Streptococcus pneumoniae is part of the normal nasopharyngeal microbiota of humans and one of the most important invasive pathogens. A genomic survey allowed establishing the occurrence of twenty-one phosphotransferase systems, seven carbohydrate uptake ABC transporters, one sodium∶solute symporter and a permease, underlining an exceptionally high capacity for uptake of carbohydrate substrates. Despite high genomic variability, combined phenotypic and genomic analysis of twenty sequenced strains did assign the substrate specificity only to two uptake systems. Systematic analysis of mutants for most carbohydrate transporters enabled us to assign a phenotype and substrate specificity to twenty-three transport systems. For five putative transporters for galactose, pentoses, ribonucleosides and sulphated glycans activity was inferred, but not experimentally confirmed and only one transport system remains with an unknown substrate and lack of any functional annotation. Using a metabolic approach, 80% of the thirty-two fermentable carbon substrates were assigned to the corresponding transporter. The complexity and robustness of sugar uptake is underlined by the finding that many transporters have multiple substrates, and many sugars are transported by more than one system. The present work permits to draw a functional map of the complete arsenal of carbohydrate utilisation proteins of pneumococci, allows re-annotation of genomic data and might serve as a reference for related species. These data provide tools for specific investigation of the roles of the different carbon substrates on pneumococcal physiology in the host during carriage and invasive infection

Clinical outcomes of implants placed in ridge-preserved versus nonpreserved sites: A 4-year randomized clinical trial

Background: Consistent bone changes occur after tooth removal, often compromising the success of implants placed within the socket left to natural healing The long-term effect of ridge preservation on implant outcomes is still unclear. Purpose: The aim of the study was to assess success and survival rates of implants placed in extraction sockets, with spontaneous healing, or grafted with cortical porcine bone, or collagenated corticocancellous porcine bone. Materials and methods: Ninety patients in need for a single premolar/molar tooth extraction and an implant treatment were selected for the present study. Patients were randomly distributed among 3 groups: sites that healed naturally (ctrl), or sites that received ridge preservation with either cortical (cort) or collagenated corticocancellous porcine bone (coll). Three months after, all the experimental sites were reentered to insert implants. Marginal bone levels were recorded; soft tissues were analyzed and summarized with the Pink Esthetic Score (PES). Forty-two patients out of 90 (initial cohort study) completed the entire follow-up of 4 years. Results: Cumulative survival and success rates for all implants were 100% at a 4-year evaluation. Mean marginal bone loss (MBL) was 1.14 ± 0.23 mm in the cort group, 1.13 ± 0.29 mm in the coll group, and 1.92 ± 0.07 mm in the ctrl group. There were no significant differences between the 2 grafting materials but MBL was significantly greater in the nongrafted sites (P value <.001). The PES resulted significantly better (9.42 ± 0.75) for the cort group than for the coll group (8.53 ± 1.18) and ctrl group (6.07 ± 1.89) at 4-year evaluation. Conclusions: Ridge preservation was more effective than natural healing in preserving marginal bone and in achieving better esthetic outcomes around implants 4 years after placement. The cortical porcine bone showed better clinical outcomes than collagenated corticocancellous porcine bone

A novel CAD/CAM-based surgical template for mandibular osteoplasty and guided implant insertion

Bone shaping is often a necessary procedure prior to implant insertion in mandibular full-arch rehabilitations. Adopting guided surgery procedures is necessary to use two distinct templates: one for bone shaping, a second for guided implant insertion. The present report describes the case of a 60-year-old patient requiring a full-arch, immediately loaded implant-supported mandibular rehabilitation. A CAD/CAM-bone supported surgical template for osteoplasty was used to develop a template for guided implant during an all-on-six immediate-loaded computer-aided implant surgery. The report describes the feasibility, accuracy and usefulness of this double, CAD/CAM developed, surgical template