855 research outputs found
Analysis of nucleotide diversity of NAT2 coding region reveals homogeneity across Native American populations and high intra-population diversity.
N-acetyltransferase 2 (NAT2), an important enzyme in clinical pharmacology, metabolizes antibiotics such as isoniazid and sulfamethoxazole, and catalyzes the transformation of aromatic and heterocyclic amines from the environment and diet into carcinogenic intermediates. Polymorphisms in NAT2 account for variability in the acetylator phenotype and the pharmacokinetics of metabolized drugs. Native Americans, settled in rural areas and large cities of Latin America, are under-represented in pharmacogenetics studies; therefore, we sequenced the coding region of NAT2 in 456 chromosomes from 13 populations from the Americas, and two from Siberia, detecting nine substitutions and 11 haplotypes. Variants *4 (37%), *5B (23%) and *7B (24%) showed high frequencies. Average frequencies of fast, intermediate and slow acetylators across Native Americans were 18, 56 and 25%, respectively. NAT2 intra-population genetic diversity for Native Americans is higher than East Asians and similar to the rest of the world, and NAT2 variants are homogeneously distributed across native populations of the continent
Schlieren Imaging and Flow Analysis on a Cone/Flare Model in the AFRL Mach 6 Ludwieg Tube Facility
High-speed Schlieren photography was utilized to visualize flow in the Air Force Research Laboratory Mach 6 Ludwieg tube facility. A 7° half-angle cone/flare model with variable nosetip radius and flare angle options was used in the study. Testing was performed at two driver tube pressures, generating freestream Reynolds numbers of 10.0x106 and 19.8x106 per meter. The variable-angle flare portion of the model provided a method for adjusting the intensity of the adverse pressure gradient at the cone/flare junction. As expected from existing literature, boundary layer separation along the cone frustum occurred further upstream as the magnitude of the adverse pressure gradient increased. Imaging of the four cone tip radii revealed a slightly positive angle of attack for the model. This conclusion was supported by asymmetrical heating contours observed in a prior infrared thermography study on the same model. Measurements of the bow shock angles downstream of the cone tip verified Mach 6 flow from the Ludwieg tube nozzle when analyzed using Taylor-Maccoll theory. Blunt cone tips generated laminar boundary layers along the cone frustum. These laminar boundary layers led to unstable behavior in the recirculation region at the cone/flare junction. Analysis of the instability revealed loosely cyclical behavior. Pressure data from the model surface would provide much greater insight into local boundary layer behavior. Future hypersonic vehicles will inevitably include numerous adverse pressure gradients. A full understanding of these regions is imperative to successful design and flight testing
Characteristics of transposable element exonization within human and mouse
Insertion of transposed elements within mammalian genes is thought to be an
important contributor to mammalian evolution and speciation. Insertion of
transposed elements into introns can lead to their activation as alternatively
spliced cassette exons, an event called exonization. Elucidation of the
evolutionary constraints that have shaped fixation of transposed elements
within human and mouse protein coding genes and subsequent exonization is
important for understanding of how the exonization process has affected
transcriptome and proteome complexities. Here we show that exonization of
transposed elements is biased towards the beginning of the coding sequence in
both human and mouse genes. Analysis of single nucleotide polymorphisms (SNPs)
revealed that exonization of transposed elements can be population-specific,
implying that exonizations may enhance divergence and lead to speciation. SNP
density analysis revealed differences between Alu and other transposed
elements. Finally, we identified cases of primate-specific Alu elements that
depend on RNA editing for their exonization. These results shed light on TE
fixation and the exonization process within human and mouse genes.Comment: 11 pages, 4 figure
Induction of humoral immune response to multiple recombinant Rhipicephalus appendiculatus antigens and their effect on tick feeding success and pathogen transmission
BACKGROUND: Rhipicephalus appendiculatus is the primary vector of Theileria parva, the etiological agent of East Coast fever (ECF), a devastating disease of cattle in sub-Saharan Africa. We hypothesized that a vaccine targeting tick proteins that are involved in attachment and feeding might affect feeding success and possibly reduce tick-borne transmission of T. parva. Here we report the evaluation of a multivalent vaccine cocktail of tick antigens for their ability to reduce R. appendiculatus feeding success and possibly reduce tick-transmission of T. parva in a natural host-tick-parasite challenge model.
METHODS: Cattle were inoculated with a multivalent antigen cocktail containing recombinant tick protective antigen subolesin as well as two additional R. appendiculatus saliva antigens: the cement protein TRP64, and three different histamine binding proteins. The cocktail also contained the T. parva sporozoite antigen p67C. The effect of vaccination on the feeding success of nymphal and adult R. appendiculatus ticks was evaluated together with the effect on transmission of T. parva using a tick challenge model.
RESULTS: To our knowledge, this is the first evaluation of the anti-tick effects of these antigens in the natural host-tick-parasite combination. In spite of evidence of strong immune responses to all of the antigens in the cocktail, vaccination with this combination of tick and parasite antigens did not appear to effect tick feeding success or reduce transmission of T. parva.
CONCLUSION: The results of this study highlight the importance of early evaluation of anti-tick vaccine candidates in biologically relevant challenge systems using the natural tick-host-parasite combination
Political branding equity: a study on Thai young voters’ intention on future forward party
Political branding reflects the political standing, ideology and image of a political party which impacts the memory and perception of voters. Party brand equity has value, property, and huge party brand trust, which influence the voting intention of voters. Therefore, integrating political branding into a political party increases the opportunities
to win elections. This research aimed to examine the case of a new political party that shows political branding as a Future Forward Party. The main research objectives were: (a) to identify the relationship between party brand equity, components and voting intention; (b) to identify the relationship between party brand equity, components and
party brand attitude; (c) to identify the relationship between party brand attitude and voting intention and (d) to determine the mediating effect of party brand attitude on the relationship between party brand equity, components, and voting intention. The research employed a cross-sectional study using survey questionnaires. The research findings indicate that party brand equity and components have significant relationships with voting intention, while party brand equity and components have significant relationships with party brand attitude. Moreover, party brand attitude has a significant relationship
with voting intention. The party brand attitude significantly mediates the relationship between party brand equity, components, and voting intention. Besides these, the findings confirmed that the Theory of Reasoned Action and the Theory of Planned Behaviour could analyse political branding
Polymorphisms within a polymorphism: SNPs in and around a polymorphic Alu insertion in intron 44 of the human dystrophin gene
A polymorphic Yb-type Alu insertion on Xp21.3 shows a genotypic gradient across worldwide populations. We used single strand conformational polymorphism (SSCP), denaturing high-pressure liquid chromatography (DHPLC), and sequencing to characterize the level of polymorphism within this region. Two novel polymorphic sites were found within the Alu insertion itself, and a further seven novel polymorphic sites in the 2-kb flanking region. Our results showed that while DHPLC was more sensitive than SSCP, the limitations of DHPLC included the lack of ability to distinguish between multiple alleles or safely identify mutations on a polymorphic background. We believe that this is the first report of polymorphic single nucleotide polymorphisms (SNPs) within a polymorphic Alu distribution and that together they promise to provide a useful marker for human population and evolutionary genetics
Vaccination against Bm86 Homologues in Rabbits Does Not Impair Ixodes ricinus Feeding or Oviposition
Human tick-borne diseases that are transmitted by Ixodes ricinus, such as Lyme
borreliosis and tick borne encephalitis, are on the rise in Europe.
Diminishing I. ricinus populations in nature can reduce tick exposure to
humans, and one way to do so is by developing an anti-vector vaccine against
tick antigens. Currently, there is only one anti-vector vaccine available
against ticks, which is a veterinary vaccine based on the tick antigen Bm86 in
the gut of Rhipicephalus microplus. Bm86 vaccine formulations cause a
reduction in the number of Rhipicephalus microplus ticks that successfully
feed, i.e. lower engorgement weights and a decrease in the number of
oviposited eggs. Furthermore, Bm86 vaccines reduce transmission of bovine
Babesia spp. Previously two conserved Bm86 homologues in I. ricinus ticks,
designated as Ir86-1 and Ir86-2, were described. Here we investigated the
effect of a vaccine against recombinant Ir86-1, Ir86-2 or a combination of
both on Ixodes ricinus feeding. Recombinant Ixodes ricinus Bm86 homologues
were expressed in a Drosophila expression system and rabbits were immunized
with rIr86-1, rIr86-2, a combination of both or ovalbumin as a control. Each
animal was infested with 50 female adults and 50 male adults Ixodes ricinus
and tick mortality, engorgement weights and egg mass were analyzed. Although
serum IgG titers against rIr86 proteins were elicited, no effect was found on
tick feeding between the rIr86 vaccinated animals and ovalbumin vaccinated
animals. We conclude that vaccination against Bm86 homologues in Ixodes
ricinus is not an effective approach to control Ixodes ricinus populations,
despite the clear effects of Bm86 vaccination against Rhipicephalus microplus
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Unexpected Role of CD8 T Cells in Accelerated Clearance of Salmonella enterica Serovar Typhimurium from H-2 Congenic mice
Salmonella infection can cause gastroenteritis in healthy individuals or a serious, systemic infection in immunocompromised patients and has a global impact. CD4 Th1 cells represent the main lymphocyte population that participates in bacterial clearance during both primary and secondary infections in mice of the H-2b haplotype. Previous studies have used congenic mice to examine the function of major histocompatibility complex (MHC) molecules in elimination of this pathogen from the host. In this study, we further characterized the ability of H-2b, H-2k, and H-2u molecules to influence adaptive immunity to Salmonella in MHC congenic mice. By depleting different cell populations during infection, we unexpectedly found that CD8 T cells, in addition to CD4 T cells, play a major role in accelerated clearance of bacteria from H-2k congenic hosts. Our data suggest that CD8 T cells accelerate clearance in some MHC congenic mouse strains and could therefore represent an unexpected contributor to the protective efficacy of Salmonella vaccines outside the typical studies in C57BL/6 mice
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