In vitro and in vivo modification of Neisseria gonorrhoeae lipooligosaccharide epitope structure by sialylation.

After growth of gonococci in the presence of cytidine monophospho-N-acetyl-neuraminic acid (CMP-NANA), their 4.5-kD lipooligosaccharide (LOS) component was increased by approximately 400 daltons, whereas the LOS of strains lacking the 4.5-kD component were unaffected. Expression of mAb-defined epitopes on the 4.5-kD component was decreased on LOS of strains grown in CMP-NANA, and treatment of the LOS with neuraminidase reversed this affect. Gonococci incubated with human PMNs also had decreased expression of the 4.5-kD+ epitopes. A detergent extract of gonococci incorporated radiolabeled NANA in the LOS, suggesting the presence of a sialyltransferase in gonococci. Exogenous sialyltransferases also could use LOS as an acceptor

Measuring, and identifying predictors of, women's perceptions of three types of breast cancer risk: population risk, absolute risk and comparative risk

Although a key function of cancer genetics services is to provide risk information, to date there has been little consistency in the way in which breast cancer risk perception has been measured. The aims of the study were to measure estimates of (i) population risk, (ii) absolute risk and (iii) comparative risk of developing breast cancer for Ashkenazi Jewish women, and to determine predictors of breast cancer risk perception. Of 152 women, 107 (70%) completed all questions. The mean (s.d.) estimates for population risk, absolute risk and comparative risk were 22.7% (15.9), 31.8% (20.6) and 1.9-fold (1.9), respectively. Most women overestimated population risk. Women at population risk generally overestimated the population risk and their own absolute risk, yet understood they are at the same risk as the population. Those with a family history understood that they are at increased risk, but underestimated the extent to which their familial risk is increased. Anxiety, high estimation of population risk and lesser family history predicted overestimation of absolute risk, whereas high estimation of population risk and a strong family history predicted underestimation of comparative risk

A discrete choice experiment of preferences for genetic counselling among Jewish women seeking cancer genetics services

To determine which aspects of breast cancer genetic counselling are important to Ashkenazi Jewish women, a discrete choice experiment was conducted. Participants consisted of 339 Australian Ashkenazi Jewish women who provided a blood sample for research used to test for Ashkenazi Jewish ancestral mutations in the genes BRCA1 and BRCA2, and were offered their genetic test result through a cancer genetics service. Main outcome measures were women's preferences for, and trade-offs between, the genetic counselling aspects of providing cancer, gene, and risk information (information); giving advice about cancer surveillance (surveillance); preparing for genetic testing (preparation); and, assistance with decision-making (direction). Respondents most valued information, about twice as much as advice about surveillance, four times as much as preparation for testing, and nine times as much as assistance with decision-making, which was least valued. Women's preferences were consistent with the major goals of genetic counselling, which include providing information and surveillance advice, and avoiding direction by facilitating autonomous decision-making. There were differences between the women in which aspects they most favoured, suggesting that counselling that elicits and responds to clients' preferences is more likely to meet clients' needs

Chemical Analysis of Cellular and Extracellular Carbohydrates of a Biofilm-Forming Strain Pseudomonas aeruginosa PA14

Background: Pseudomonas aeruginosa is a Gram-negative bacterium and an opportunistic pathogen, which causes persisting life-threatening infections in cystic fibrosis (CF) patients. Biofilm mode of growth facilitates its survival in a variety of environments. Most P. aeruginosa isolates, including the non-mucoid laboratory strain PA14, are able to form a thick pellicle, which results in a surface-associated biofilm at the air-liquid (A\ufffdL) interface in standing liquid cultures. Exopolysaccharides (EPS) are considered as key components in the formation of this biofilm pellicle. In the non-mucoid P. aeruginosa strain PA14, the \ufffd\ufffdscaffolding\ufffd\ufffd polysaccharides of the biofilm matrix, and the molecules responsible for the structural integrity of rigid A\ufffdL biofilm have not been identified. Moreover, the role of LPS in this process is unclear, and the chemical structure of the LPS O-antigen of PA14 has not yet been elucidated. Principal Findings: In the present work we carried out a systematic analysis of cellular and extracellular (EC) carbohydrates of P. aeruginosa PA14. We also elucidated the chemical structure of the LPS O-antigen by chemical methods and 2-D NMR spectroscopy. Our results showed that it is composed of linear trisaccharide repeating units, identical to those described for P. aeruginosa Lanyi type O:2a,c (Lanyi-Bergman O-serogroup 10a, 10c; IATS serotype 19) and having the following structure: -4)-a-L-GalNAcA-(1\ufffd3)-a-D-QuiNAc-(1\ufffd3)- a-L-Rha-(1-. Furthermore, an EC O-antigen polysaccharide (EC O-PS) and the glycerol-phosphorylated cyclic b-(1,3)-glucans were identified in the culture supernatant of PA14, grown statically in minimal medium. Finally, the extracellular matrix of the thick biofilm formed at the A-L interface contained, in addition to eDNA, important quantities (at least ,20% of dry weight) of LPS-like material. Conclusions: We characterized the chemical structure of the LPS O-antigen and showed that the O-antigen polysaccharide is an abundant extracellular carbohydrate of PA14. We present evidence that LPS-like material is found as a component of a biofilm matrix of P. aeruginosa.Peer reviewed: YesNRC publication: Ye

U-Shaped Relation between Plasma Oxytocin Levels and Behavior in the Trust Game

10.1371/journal.pone.0051095PLoS ONE712

Development of a Multivalent Subunit Vaccine against Tularemia Using Tobacco Mosaic Virus (TMV) Based Delivery System

Francisella tularensisis a facultative intracellular pathogen, and is the causative agent of a fatal human disease known as tularemia. F. tularensis is classified as a Category A Biothreat agent by the CDC based on its use in bioweapon programs by several countries in the past and its potential to be used as an agent of bioterrorism. No licensed vaccine is currently available for prevention of tularemia. In this study, we used a novel approach for development of a multivalent subunit vaccine against tularemia by using an efficient tobacco mosaic virus (TMV) based delivery platform. The multivalent subunit vaccine was formulated to contain a combination of F. tularensis protective antigens: OmpA-like protein (OmpA), chaperone protein DnaK and lipoprotein Tul4 from the highly virulent F. tularensisSchuS4 strain. Two different vaccine formulations and immunization schedules were used. The immunized mice were challenged with lethal (10xLD100) doses of F. tularensisLVS on day 28 of the primary immunization and observed daily for morbidity and mortality. Results from this study demonstrate that TMV can be used as a carrier for effective delivery of multiple F. tularensisantigens. TMV-conjugate vaccine formulations are safe and multiple doses can be administered without causing any adverse reactions in immunized mice. Immunization with TMV-conjugated F. tularensisproteins induced a strong humoral immune response and protected mice against respiratory challenges with very high doses of F. tularensis LVS. This study provides a proof-of-concept that TMV can serve as a suitable platform for simultaneous delivery of multiple protective antigens of F. tularensis. Refinement of vaccine formulations coupled with TMV-targeting strategies developed in this study will provide a platform for development of an effective tularemia subunit vaccine as well as a vaccination approach that may broadly be applicable to many other bacterial pathogens

A Major Role for Side-Chain Polyglutamine Hydrogen Bonding in Irreversible Ataxin-3 Aggregation

The protein ataxin-3 consists of an N-terminal globular Josephin domain (JD) and an unstructured C-terminal region containing a stretch of consecutive glutamines that triggers the neurodegenerative disorder spinocerebellar ataxia type 3, when it is expanded beyond a critical threshold. The disease results from misfolding and aggregation, although the pathway and structure of the aggregation intermediates are not fully understood. In order to provide insight into the mechanism of the process, we monitored the aggregation of a normal (AT3Q24) ataxin-3, an expanded (AT3Q55) ataxin-3, and the JD in isolation. We observed that all of them aggregated, although the latter did so at a much slower rate. Furthermore, the expanded AT3Q55 displayed a substantially different behavior with respect to the two other variants in that at the latest stages of the process it was the only one that did the following: i) lost its reactivity towards an anti-oligomer antibody, ii) generated SDS-insoluble aggregates, iii) gave rise to bundles of elongated fibrils, and iv) displayed two additional bands at 1604 and 1656 cm−1 in FTIR spectroscopy. Although these were previously observed in other aggregated polyglutamine proteins, no one has assigned them unambiguously, yet. By H/D exchange experiments we show for the first time that they can be ascribed to glutamine side-chain hydrogen bonding, which is therefore the hallmark of irreversibly SDS-insoluble aggregated protein. FTIR spectra also showed that main-chain intermolecular hydrogen bonding preceded that of glutamine side-chains, which suggests that the former favors the latter by reorganizing backbone geometry

The striatum multiplexes contextual and kinematic information to constrain motor habits execution

International audienceThe striatum is required for the acquisition of procedural memories, but its contribution to motor control once learning has occurred is unclear. We created a task in which rats learned a difficult motor sequence characterized by fine-tuned changes in running speed adjusted to spatial and temporal constraints. After training and extensive practice, we found that the behavior was habitual, yet tetrode recordings in the dorsolateral striatum (DLS) revealed continuous integrative representations of running speed, position and time. These representations were weak in naive rats that were hand-guided to perform the same sequence and developed slowly after learning. Finally, DLS inactivation in well-trained animals preserved the structure of the sequence while increasing its trial-by-trial variability. We conclude that, after learning, the DLS continuously integrates task-relevant information to constrain the execution of motor habits. Our results provide a straightforward mechanism by which the basal ganglia may contribute to habit formation and motor control