Comparison of the intracellular trafficking itinerary of ctla-4 orthologues.

CTLA-4 is an essential inhibitor of T cell immune responses. At steady state, most CTLA-4 resides in intracellular compartments due to constitutive internalisation mediated via a tyrosine based endocytic motif (YVKM) within the cytoplasmic domain. This domain is highly conserved in mammals suggesting strong selective pressure. In contrast, the C-terminal domain varies considerably in non-mammals such as fish, xenopus and birds. We compared the ability of the C-terminus of these species to direct the trafficking of CTLA-4 with human CTLA-4. Using a chimeric approach, endocytosis was found to be conserved between human, xenopus and chicken CTLA-4 but was reduced substantially in trout CTLA-4, which lacks the conserved YXXM motif. Nevertheless, we identified an alternative YXXF motif in trout CTLA-4 that permitted limited endocytosis. Post-internalisation, CTLA-4 was either recycled or targeted for degradation. Human and chicken CTLA-4, which contain a YVKM motif, showed efficient recycling compared to xenopus CTLA-4 which contains a less efficient YEKM motif. Specific mutation of this motif in human CTLA-4 reduced receptor recycling. These findings suggest evolutionary development in the endocytic and recycling potential of CTLA-4, which may facilitate more refined functions of CTLA-4 within the mammalian immune system

Identification of Novel Proteins in Neospora caninum Using an Organelle Purification and Monoclonal Antibody Approach

Neospora caninum is an important veterinary pathogen that causes abortion in cattle and neuromuscular disease in dogs. Neospora has also generated substantial interest because it is an extremely close relative of the human pathogen Toxoplasma gondii, yet does not appear to infect humans. While for Toxoplasma there are a wide array of molecular tools and reagents available for experimental investigation, relatively few reagents exist for Neospora. To investigate the unique biological features of this parasite and exploit the recent sequencing of its genome, we have used an organelle isolation and monoclonal antibody approach to identify novel organellar proteins and develop a wide array of probes for subcellular localization. We raised a panel of forty-six monoclonal antibodies that detect proteins from the rhoptries, micronemes, dense granules, inner membrane complex, apicoplast, mitochondrion and parasite surface. A subset of the proteins was identified by immunoprecipitation and mass spectrometry and reveal that we have identified and localized many of the key proteins involved in invasion and host interaction in Neospora. In addition, we identified novel secretory proteins not previously studied in any apicomplexan parasite. Thus, this organellar monoclonal antibody approach not only greatly enhances the tools available for Neospora cell biology, but also identifies novel components of the unique biological characteristics of this important veterinary pathogen

The prevalence of dental erosion and associated risk factors in 12-13-year-old school children in Southern China

<p>Abstract</p> <p>Background</p> <p>Dental erosion has been investigated in developed and developing countries and the prevalence varies considerably in different countries, geographic locations, and age groups. With the lifestyle of the Chinese people changing significantly over the decades, dental erosion has begun to receive more attention. However, the information about dental erosion in China is scarce. The purpose of this study was to explore the prevalence of dental erosion and associated risk factors in 12-13-year-old school children in Guangzhou, Southern China.</p> <p>Methods</p> <p>This cross-sectional survey was performed by two trained, calibrated examiners. A stratified random sample of 12-13-year-old children (774 boys and 725 girls) from 10 schools was examined for dental erosion using the diagnostic criteria of Eccles and the index of O'Sullivan was applied to record the distribution, severity, and amount of the lesions. Data on the socio-economic status, health behaviours, and general health involved in the etiology of dental erosion were obtained from a self-completed questionnaire. The analyses were performed using SPSS software.</p> <p>Results</p> <p>At least one tooth surface with signs of erosion was found in 416 children (27.3%). The most frequently affected teeth were the central incisors (upper central incisors, 16.3% and 15.9%; lower central incisors, 17.4% and 14.8%). The most frequently affected surface was the incisal or occlusal edge (43.2%). The loss of enamel contour was present in 54.6% of the tooth surfaces with erosion. Of the affected tooth surfaces, 69.3% had greater than one-half of the tooth surface was affected. The results from logistic regression analysis demonstrated that the children who were female, consumed carbonated drinks once a week or more, and those whose mothers were educated to the primary level tended to have more dental erosion.</p> <p>Conclusions</p> <p>Dental erosion in 12-13-year-old Chinese school children is becoming a significant problem. A strategy of offering preventive care, including more campaigns promoting a healthier lifestyle for those at risk of dental erosion should be conducted in Chinese children and their parents.</p

The Dispanins: A Novel Gene Family of Ancient Origin That Contains 14 Human Members

The Interferon induced transmembrane proteins (IFITM) are a family of transmembrane proteins that is known to inhibit cell invasion of viruses such as HIV-1 and influenza. We show that the IFITM genes are a subfamily in a larger family of transmembrane (TM) proteins that we call Dispanins, which refers to a common 2TM structure. We mined the Dispanins in 36 eukaryotic species, covering all major eukaryotic groups, and investigated their evolutionary history using Bayesian and maximum likelihood approaches to infer a phylogenetic tree. We identified ten human genes that together with the known IFITM genes form the Dispanin family. We show that the Dispanins first emerged in eukaryotes in a common ancestor of choanoflagellates and metazoa, and that the family later expanded in vertebrates where it forms four subfamilies (A–D). Interestingly, we also find that the family is found in several different phyla of bacteria and propose that it was horizontally transferred to eukaryotes from bacteria in the common ancestor of choanoflagellates and metazoa. The bacterial and eukaryotic sequences have a considerably conserved protein structure. In conclusion, we introduce a novel family, the Dispanins, together with a nomenclature based on the evolutionary origin

CovR-Controlled Global Regulation of Gene Expression in Streptococcus mutans

CovR/S is a two-component signal transduction system (TCS) that controls the expression of various virulence related genes in many streptococci. However, in the dental pathogen Streptococcus mutans, the response regulator CovR appears to be an orphan since the cognate sensor kinase CovS is absent. In this study, we explored the global transcriptional regulation by CovR in S. mutans. Comparison of the transcriptome profiles of the wild-type strain UA159 with its isogenic covR deleted strain IBS10 indicated that at least 128 genes (∼6.5% of the genome) were differentially regulated. Among these genes, 69 were down regulated, while 59 were up regulated in the IBS10 strain. The S. mutans CovR regulon included competence genes, virulence related genes, and genes encoded within two genomic islands (GI). Genes encoded by the GI TnSmu2 were found to be dramatically reduced in IBS10, while genes encoded by the GI TnSmu1 were up regulated in the mutant. The microarray data were further confirmed by real-time RT-PCR analyses. Furthermore, direct regulation of some of the differentially expressed genes was demonstrated by electrophoretic mobility shift assays using purified CovR protein. A proteomic study was also carried out that showed a general perturbation of protein expression in the mutant strain. Our results indicate that CovR truly plays a significant role in the regulation of several virulence related traits in this pathogenic streptococcus

Enhanced catecholamine transporter binding in the locus coeruleus of patients with early Parkinson disease

<p>Abstract</p> <p>Background</p> <p>Studies in animals suggest that the noradrenergic system arising from the locus coeruleus (LC) and dopaminergic pathways mutually influence each other. Little is known however, about the functional state of the LC in patients with Parkinson disease (PD).</p> <p>Methods</p> <p>We retrospectively reviewed clinical and imaging data of 94 subjects with PD at an early clinical stage (Hoehn and Yahr stage 1-2) who underwent single photon computed tomography imaging with FP-CIT ([¹²³I] N-ω-fluoropropyl-2β-carbomethoxy-3β-(4-iodophenyl) tropane). FP-CIT binding values from the patients were compared with 15 healthy subjects: using both a voxel-based whole brain analysis and a volume of interest analysis of <it>a priori </it>defined brain regions.</p> <p>Results</p> <p>Average FP-CIT binding in the putamen and caudate nucleus was significantly reduced in PD subjects (43% and 57% on average, respectively; p < 0.001). In contrast, subjects with PD showed an increased binding in the LC (166% on average; p < 0.001) in both analyses. LC-binding correlated negatively with striatal FP-CIT binding values (caudate: contralateral, ρ = -0.28, p < 0.01 and ipsilateral ρ = -0.26, p < 0.01; putamen: contralateral, ρ = -0.29, p < 0.01 and ipsilateral ρ = -0.29, p < 0.01).</p> <p>Conclusions</p> <p>These findings are consistent with an up-regulation of noradrenaline reuptake in the LC area of patients with early stage PD, compatible with enhanced noradrenaline release, and a compensating activity for degeneration of dopaminergic nigrostriatal projections.</p

Age adjustment in ecological studies: using a study on arsenic ingestion and bladder cancer as an example

<p>Abstract</p> <p>Background</p> <p>Despite its limitations, ecological study design is widely applied in epidemiology. In most cases, adjustment for age is necessary, but different methods may lead to different conclusions. To compare three methods of age adjustment, a study on the associations between arsenic in drinking water and incidence of bladder cancer in 243 townships in Taiwan was used as an example.</p> <p>Methods</p> <p>A total of 3068 cases of bladder cancer, including 2276 men and 792 women, were identified during a ten-year study period in the study townships. Three methods were applied to analyze the same data set on the ten-year study period. The first (Direct Method) applied direct standardization to obtain standardized incidence rate and then used it as the dependent variable in the regression analysis. The second (Indirect Method) applied indirect standardization to obtain standardized incidence ratio and then used it as the dependent variable in the regression analysis instead. The third (Variable Method) used proportions of residents in different age groups as a part of the independent variables in the multiple regression models.</p> <p>Results</p> <p>All three methods showed a statistically significant positive association between arsenic exposure above 0.64 mg/L and incidence of bladder cancer in men and women, but different results were observed for the other exposure categories. In addition, the risk estimates obtained by different methods for the same exposure category were all different.</p> <p>Conclusions</p> <p>Using an empirical example, the current study confirmed the argument made by other researchers previously that whereas the three different methods of age adjustment may lead to different conclusions, only the third approach can obtain unbiased estimates of the risks. The third method can also generate estimates of the risk associated with each age group, but the other two are unable to evaluate the effects of age directly.</p