700 research outputs found
Fumonisin-induced hepatocarcinogenesis: mechanisms related to cancer initiation and promotion.
We review the hepatocarcinogenic effects of fungal cultures of Fusarium verticillioides(= Fusarium moniliforme) strain MRC 826 in male BD IX rats. Subsequent chemical analyses of the fumonisin B (FB) mycotoxin content in the culture material used and long-term carcinogenesis studies with purified FB1 provide information about dose-response effects, relevance of hepatotoxicity during FB1-induced carcinogenesis, and the existence of a no-effect threshold. Fumonisin intake levels of between 0.08 and 0.16 mg FB/100 g body weight (bw)/day over approximately 2 years produce liver cancer in male BD IX rats. Exposure levels < 0.08 mg FB/100 g bw/day fail to induce cancer, although mild toxic and preneoplastic lesions are induced. The nutritional status of the diets used in the long-term experiments was marginally deficient in lipotropes and vitamins and could have played an important modulating role in fumonisin-induced hepatocarcinogenesis. Short-term studies in a cancer initiation/promotion model in rat liver provided important information about the possible mechanisms involved during the initial stages of cancer development by this apparently nongenotoxic mycotoxin. These studies supported the findings of long-term investigations indicating that a cytotoxic/proliferative response is required for cancer induction and that a no-effect threshold exists for cancer induction. The mechanisms proposed for cancer induction are highlighted and include the possible role of oxidative damage during initiation and the disruption of lipid metabolism, integrity of cellular membranes, and altered growth-regulatory responses as important events during promotion
Evolution, appearance, and occupational success
Visual characteristics, including facial appearance, are thought to play an important role in a variety of judgments and decisions that have real occupational outcomes in many settings. Indeed, there is growing evidence suggesting that appearance influences hiring decisions and even election results. For example, attractive individuals are more likely to be hired, taller men earn more, and the facial appearance of candidates has been linked to real election outcomes. In this article, we review evidence linking physical appearance to occupational success and evaluate the hypothesis that appearance based biases are consistent with predictions based on evolutionary theories of coalition formation and leadership choice. We discuss why appearance based effects are so pervasive, addressing ideas about a "kernel of truth" in attributions and about coalitional psychology. We additionally highlight that appearance may be differently related to success at work according to the types of job or task involved. For example, leaders may be chosen because the characteristics they possess are seen as best suited to lead in particular situations. During a time of war, a dominant-appearing leader may inspire confidence and intimidate enemies while during peace-time, when negotiation and diplomacy are needed, interpersonal skills may outweigh the value of a dominant leader. In line with these ideas, masculine-faced leaders are favored in war-time scenarios while feminine-faced leaders are favored in peace-time scenarios. We suggest that such environment or task specific competencies may be prevalent during selection processes, whereby individuals whose appearance best matches perceived task competences are most likely selected, and propose the general term "task-congruent selection" to describe these effects. Overall, our review highlights how potentially adaptive biases could influence choices in the work place. With respect to certain biases, understanding their origin and current prevalence is important in order to potentially reduce discrimination in the work place
Platforms to differentiate exotic pathovars of plant bacteria
Many of the EPPs that pose the biggest threat to the biosecurity of Australia’s plant industries are bacterial, but difficulties in identification to the subspecific or ‘ pathovar ’ level can seriously delay incursion management and affect market access. Pathovars are defined by host specificity so bio assays remain the definitive means of identification, but these require high level physical containment and can be slow and subjective , delaying diagnosis . Some pathovar - specific serological and molecular tests are available but better diagnostic methods are often required. This project used proteomics and metabolomics, platforms that identify functional molecules potentially associated with plant - pathogen interactions, to identify biomarkers that differentiate pathovars in species of Xanthomonas .
Membrane - associated proteins from a collection of bacterial isolates were compared on 2Dimensional gels. Proteins that were found to be differentially expressed between distinct pathovars may be important modulators of host specificity so they were identified and the genes that encode them located by reference to genomic sequences . DNA - based assays targeting these genes were designed and validated for their specificity to the pathovar level . We have developed two new assays that provide levels of specificity not reported elsewhere in the literature. These assays specifically target the bacteria causing the different forms of citrus canker, but without cross - reaction to the closely - related organisms causing bacterial blight on cotton and Citrus Bacterial Spot. The molecular assays will be incorporated into the National Diagnostic Protocol for citrus canker through the SPHDS process.
The metabolomics component has analysed metabolite expression in selected bacterial pathovars. Results showed separation between the different pathovars based on differential levels of expression of particular metabolites. These metabolites may be important determinants of pathogenicity.
Neither proteomics nor metabolomics had been implemented before in the study of phytopathogenic bacteria and whilst both proved to be technically demanding, each delivered new biomarkers that differentiate phytopathogenic bacteria to a subspecific level . This confirmed the viability of these approaches as platforms to discover novel diagnostic targets. The new methods developed will be implemented into the national incursion response capability , improving the specificity of diagnostic testing available and reducing the possibility of false positive diagnosis .
The project has fostered new collaborative partnerships both nationally (NSW, Victoria, WA) and internationally (to Thailand and the USA). The next phase of this work will provide a strong start - up project to the Plant Biosecurity Cooperative Research Centre ( PBCRC ) . This project has directly enhanced the plant bacteriology capacity of NSW and Australia trough the recruitment and training of science professionals and an undergraduate student , and supported the specialist training of a Thai scientist through allied project CRC20093
Omega-3 Fatty Acid and Iron Supplementation Alone, but Not in Combination, Lower Inflammation and Anemia of Infection in Mycobacterium tuberculosis-Infected Mice
Progressive inflammation and anemia are common in tuberculosis (TB) and linked to poor clinical outcomes. Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) have inflammation-resolving properties, whereas iron supplementation in TB may have limited efficacy and enhance bacterial growth. We investigated effects of iron and EPA/DHA supplementation, alone and in combination, on inflammation, anemia, iron status markers and clinical outcomes in Mycobacterium tuberculosis-infected C3HeB/FeJ mice. One week post-infection, mice received the AIN-93 diet without (control) or with supplemental iron (Fe), EPA/DHA, or Fe+EPA/DHA for 3 weeks. Mice supplemented with Fe or EPA/DHA had lower soluble transferrin receptor, ferritin and hepcidin than controls, but these effects were attenuated in Fe+EPA/DHA mice. EPA/DHA increased inflammation-resolving lipid mediators and lowered lung IL-1α, IFN-γ, plasma IL-1β, and TNF-α. Fe lowered lung IL-1α, IL-1β, plasma IL-1β, TNF-α, and IL-6. However, the cytokine-lowering effects in the lungs were attenuated with Fe+EPA/DHA. Mice supplemented with EPA/DHA had lower lung bacterial loads than controls, but this effect was attenuated in Fe+EPA/DHA mice. Thus, individually, post-infection EPA/DHA and iron supplementation lowered systemic and lung inflammation and mitigated anemia of infection in TB, but not when combined. EPA/DHA also enhanced bactericidal effects and could support inflammation resolution and management of anemia
Adjunct n-3 Long-Chain Polyunsaturated Fatty Acid Treatment in Tuberculosis Reduces Inflammation and Improves Anemia of Infection More in C3HeB/FeJ Mice With Low n-3 Fatty Acid Status Than Sufficient n-3 Fatty Acid Status
Populations at risk for tuberculosis (TB) may have a low n-3 polyunsaturated fatty acid
(PUFA) status. Our research previously showed that post-infection supplementation of
n-3 long-chain PUFA (LCPUFA) in TB without TB medication was beneficial in n-3
PUFA sufficient but not in low-status C3HeB/FeJ mice. In this study, we investigated
the effect of n-3 LCPUFA adjunct to TB medication in TB mice with a low compared
to a sufficient n-3 PUFA status. Mice were conditioned on an n-3 PUFA-deficient (n-
3FAD) or n-3 PUFA-sufficient (n-3FAS) diet for 6 weeks before TB infection. Postinfection
at 2 weeks, both groups were switched to an n-3 LCPUFA [eicosapentaenoic
acid (EPA)/docosahexaenoic acid (DHA)] supplemented diet and euthanized at 4- and
14- days post-treatment. Iron and anemia status, bacterial loads, lung pathology, lung
cytokines/chemokines, and lung lipid mediators were measured. Following 14 days of
treatment, hemoglobin (Hb) was higher in the n-3FAD than the untreated n-3FAS group
(p = 0.022), whereas the n-3FAS (drug) treated control and n-3FAS groups were not. Proinflammatory
lung cytokines; interleukin-6 (IL-6) (p = 0.011), IL-1a (p = 0.039), MCP1
(p = 0.003), MIP1- a (p = 0.043), and RANTES (p = 0.034); were lower, and the antiinflammatory
cytokine IL-4 (p=0.002) and growth factor GMCSF (p=0.007) were higher
in the n-3FAD compared with the n-3FAS mice after 14 days. These results suggest that
n-3 LCPUFA therapy in TB-infected mice, in combination with TB medication, may
improve anemia of infection more in low n-3 fatty acid status than sufficient status mice.
Furthermore, the low n-3 fatty acid status TB mice supplemented with n-3 LCPUFA
showed comparatively lower cytokine-mediated inflammation despite presenting with
lower pro-resolving lipid mediators
Omega-3 long-chain polyunsaturated fatty acids promote antibacterial and inflammation-resolving effects in Mycobacterium tuberculosis-infected C3HeB/FeJ mice, dependent on fatty acid status
AbstractNon-resolving inflammation is characteristic of tuberculosis (TB). Given their inflammation-resolving properties,n-3 long-chain PUFA (n-3 LCPUFA) may support TB treatment. This research aimed to investigate the effects ofn-3 LCPUFA on clinical and inflammatory outcomes ofMycobacterium tuberculosis-infected C3HeB/FeJ mice with either normal or lown-3 PUFA status before infection. Using a two-by-two design, uninfected mice were conditioned on either ann-3 PUFA-sufficient (n-3FAS) or -deficient (n-3FAD) diet for 6 weeks. One week post-infection, mice were randomised to eithern-3 LCPUFA supplemented (n-3FAS/n-3+ andn-3FAD/n-3+) or continued onn-3FAS orn-3FAD diets for 3 weeks. Mice were euthanised and fatty acid status, lung bacterial load and pathology, cytokine, lipid mediator and immune cell phenotype analysed.n-3 LCPUFA supplementation inn-3FAS mice lowered lung bacterial loads (P= 0·003), T cells (P= 0·019), CD4+T cells (P= 0·014) and interferon (IFN)-γ(P< 0·001) and promoted a pro-resolving lung lipid mediator profile. Compared withn-3FAS mice, then-3FAD group had lower bacterial loads (P= 0·037), significantly higher immune cell recruitment and a more pro-inflammatory lipid mediator profile, however, significantly lower lung IFN-γ, IL-1α, IL-1βand IL-17, and supplementation in then-3FAD group provided no beneficial effect on lung bacterial load or inflammation. Our study provides the first evidence thatn-3 LCPUFA supplementation has antibacterial and inflammation-resolving benefits in TB when provided 1 week after infection in the context of a sufficientn-3 PUFA status, whilst a lown-3 PUFA status may promote better bacterial control and lower lung inflammation not benefiting fromn-3 LCPUFA supplementation
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