Metabolomic profiling and stable isotope labelling of Trichomonas vaginalis and Tritrichomonas foetus reveal major differences in amino acid metabolism including the production of 2-hydroxyisocaproic acid, cystathionine and S-methylcysteine

Trichomonas vaginalis and Tritrichomonas foetus are pathogens that parasitise, respectively, human and bovine urogenital tracts causing disease. Using LC-MS, reference metabolomic profiles were obtained for both species and stable isotope labelling with D-[U-13C6] glucose was used to analyse central carbon metabolism. This facilitated a comparison of the metabolic pathways of T. vaginalis and T. foetus, extending earlier targeted biochemical studies. 43 metabolites, whose identities were confirmed by comparison of their retention times with authentic standards, occurred at more than 3-fold difference in peak intensity between T. vaginalis and T. foetus. 18 metabolites that were removed from or released into the medium during growth also showed more than 3-fold difference between the species. Major differences were observed in cysteine and methionine metabolism in which homocysteine, produced as a bi-product of trans-methylation, is catabolised by methionine γ-lyase in T. vaginalis but converted to cystathionine in T. foetus. Both species synthesise methylthioadenosine by an unusual mechanism, but it is not used as a substrate for methionine recycling. T. vaginalis also produces and exports high levels of S-methylcysteine, whereas only negligible levels were found in T. foetus which maintains significantly higher intracellular levels of cysteine. 13C-labeling confirmed that both cysteine and S-methylcysteine are synthesised by T. vaginalis; S-methylcysteine can be generated by recombinant T. vaginalis cysteine synthase using phosphoserine and methanethiol. T. foetus contained higher levels of ornithine and citrulline than T. vaginalis and exported increased levels of putrescine, suggesting greater flux through the arginine dihydrolase pathway. T. vaginalis produced and exported hydroxy acid derivatives of certain amino acids, particularly 2-hydroxyisocaproic acid derived from leucine, whereas negligible levels of these metabolites occurred in T. foetus

Proposed Early Cambrian cephalopods are chimaeras, the oldest known cephalopods are 30 m.y. younger

Peer reviewe

U-Pb Zircon Dates from North American and British Avalonia Bracket the Lower–Middle Cambrian Boundary Interval, with Evaluation of the Miaolingian Series as a Global Unit

High-precision U-Pb zircon ages on SE Newfoundland tuffs now bracket the Avalonian Lower–Middle Cambrian boundary. Upper Lower Cambrian Brigus Formation tuffs yield depositional ages of 507.91 ± 0.07 Ma (Callavia broeggeri Zone) and 507.67 ± 0.08 Ma and 507.21 ± 0.13 Ma (Morocconus-Condylopyge eli Assemblage interval). Lower Middle Cambrian Chamberlain’s Brook Formation tuffs have depositional ages of 506.34 ± 0.21 Ma (Kiskinella cristata Zone) and 506.25 ± 0.07 Ma (Eccaparadoxides bennetti Zone). The composite unconformity separating the Brigus and Chamberlain’s Brook formations is constrained between these ages. An Avalonian Lower–Middle Cambrian boundary between 507.2 ± 0.1 and 506.3 ± 0.2 Ma is consistent with maximum depositional age constraints from southwest Laurentia, which indicate an age for the base of the Miaolingian Series, as locally interpreted, of ≤ 506.6 ± 0.3 Ma. The Miaolingian Series’ base is interpreted as correlative within ≤ 0.3 ± 0.3 Ma between Cambrian palaeocontinents, although its exact synchrony is questionable due to taxonomic problems with a possible Oryctocephalus indicus-plexus, invariable dysoxic lithofacies control of O. indicus and diachronous occurrence of O. indicus in temporally distinct δ13C chemozones in South China and SW Laurentia. The lowest occurrence of O. indicus assemblages is linked to onlap (epeirogenic or eustatic) of dysoxic facies. A united Avalonia is shown by late Early Cambrian volcanics in SW New Brunswick; Cape Breton Island; SE Newfoundland; and the Wrekin area, England. The new U-Pb ages revise Avalonian geological evolution as they show rapid epeirogenic changes through depositional sequences 4a–6

An exploration of gender differences and gender-specific influences on the physical activity and sedentary behaviours of adults with intellectual disabilities

Background. Women with intellectual disabilities experience greater risk of health inequalities. Low physical activity (PA) and high sedentary behaviour (SB) levels may contribute to this. The influence of gender on PA and SB is unknown for adults with intellectual disabilities. This thesis aimed to 1. Investigate and quantify gender differences in the PA and SB of adults with intellectual disabilities; 2. Identify potential gender-specific influences on the PA and SB of adults with intellectual disabilities. Sequential studies addressed these aims. Study 1. A systematic review and meta-analysis were conducted to quantify gender differences in the PA and SB levels of adults with intellectual disabilities in the extant literature. Seven databases were searched. Significant gender differences were observed for step counts and moderate to vigorous PA (MVPA), with women less active than men. Mixed findings were reported for SB with limited studies identified. Study 2. This study aimed to identify gender-specific correlates and to quantify gender differences in objectively measured MVPA and SB. A secondary data analysis was conducted using pooled baseline data of two Glasgow based interventions (n = 143 adults with intellectual disabilities: 51.7% women). Bivariate, followed by multivariate linear regressions identified gender-specific correlates using data split by gender. Independent samples t-tests assessed gender differences. No gender differences were reported in MVPA and SB levels. Gender differences in influences were reported; all variables were at an intrapersonal level. Study 3. Gender-specific correlates, and gender differences in self-reported PA and SB were assessed in a secondary data analysis of a population-based study. Participants included n = 725 adults with intellectual disabilities (44.9% women) living in Greater Glasgow. Correlates were at an individual and environmental level. Gender differences in PA and SB levels were measured using Chi-square tests. Multivariate logistic regression with purposeful selection of variables were conducted, using data split by gender. Men were significantly more likely to meet physical activity guidelines. Gender differences in the correlates identified were observed. Study 4. Feasibility of social support network methods in the context of the leisure activities promoted was assessed using a mixed-methods design. Data were collected to assess gender differences in the sources of support, types of activities promoted (PA or SB), and perceptions of social support for PA. This study was cancelled due to the COVID-9 pandemic. N = 3 adults with intellectual disabilities participated prior to cancellation. The data were analysed through thematic analysis, and descriptive statistics calculated for quantitative data. Attempts to adapt the study for remote working were not feasible. Study 5. This study was developed to mitigate the impact of the COVID-19 pandemic. The study aimed to identify gender-specific social and environmental correlates, identify gender differences in PA and SB levels, and the types of activities engaged in by adults with intellectual disabilities. A secondary data analysis was conducted using the British Cohort Study age 46 sweep. Cognitive tests at age 5 and 10 sweeps were used to identify people with potential intellectual disabilities. Outcome data included objectively measured PA and SB, and self-reported activities engaged in. Independent samples t-test assessed gender differences in PA and SB levels. Chi-square tests were used to explore gender differences in the types of activities engaged in. Using data split by gender, bivariate linear regressions, and multivariate linear regression were conducted to identify gender-specific correlates. No significant gender-specific correlates were identified, other than health limiting moderate activities associated with lower step counts for women. Descriptively, men engaged in more sports than women, but rates were low for both genders. Women were significantly more likely to be involved in daily household activities contributing to PA. There were no significant gender differences in the types of SB engaged in. Conclusions. Men with intellectual disabilities engaged in more PA than women, but there were no gender differences present in SB. The PA levels were low for both men and women. There was evidence of gender-specific influences, however more research is required. Exploration into gender differences in PA and SB provides an in-depth understanding of the lifestyles of adults with intellectual disabilities. Failure of past research to consider the influence of gender exacerbates the health inequalities experienced

The combined molecular adjuvant CASAC enhances the CD8+ T cell response to a tumor-associated self-antigen in aged, immunosenescent mice

BACKGROUND: Ineffective induction of T cell mediated immunity in older individuals remains a persistent challenge for vaccine development. Thus, there is a need for more efficient and sophisticated adjuvants that will complement novel vaccine strategies for the elderly. To this end, we have investigated a previously optimized, combined molecular adjuvant, CASAC (Combined Adjuvant for Synergistic Activation of Cellular immunity), incorporating two complementary Toll-like receptor agonists, CpG and polyI:C, a class-II epitope, and interferon (IFN)-γ in aged mice. FINDINGS: In aged mice with typical features of immunosenescence, antigen specific CD8+ T cell responses were stimulated after serial vaccinations with CASAC or Complete/Incomplete Freund's Adjuvant (CFA/IFA) and a class I epitope, deriving either from ovalbumin (SIINFEKL, SIL) or the melanoma-associated self-antigen, tyrosinase-related protein-2 (SVYDFFVWL, SVL). Pentamer analysis revealed that aged, CASAC/SIL-vaccinated animals had substantially higher frequencies of H-2K(b)/SIL-specific CD8+ T cells compared to the CFA/IFA-vaccinated groups. Similarly, higher frequencies of H-2K(b)/SVL-pentamer+ and IFN-γ+ CD8+ T cells were detected in the aged, CASAC + SVL-vaccinated mice than in their CFA/IFA-vaccinated counterparts. In both antigen settings, CASAC promoted significantly better functional CD8+ T cell activity. CONCLUSION: These studies demonstrate that functional CD8+ T cells, specific for both foreign and tumour-associated self-antigens, can be effectively induced in aged immunosenescent mice using the novel multi-factorial adjuvant CASAC

CCR5 antagonism impacts vaccination response and immune profile in HIV-1 infection.

Maraviroc (MVC) is the first licensed antiretroviral therapeutic agent to target a host cell surface molecule, and successful HIV-1 entry blockade by this C-C chemokine receptor type 5 (CCR5)-antagonist potentiates immunomodulation. We hypothesized that MVC intensification impacts immunization responses, T-cell phenotype, function and delayed type hypersensitivity (DTH) in HIV-1+ subjects. A 24-wk, double-blinded, placebo-controlled study of the addition of MVC to suppressive antiretroviral therapy in HIV-1+ persons was performed. Subjects received DTH tests, intramuscular tetanus, meningococcal and oral cholera immunizations. Antibody titers, T-cell function and phenotype were assessed. Of 157 patients referred, 47 were randomized 1:1; MVC:placebo. MVC enhanced meningococcal neo-immunization, blunted cholera response and expedited lymphoproliferation to tetanus boost, without affecting recall humoral response. Anti-HIV-1 group-specific antigen (Gag) and tetanus toxoid (TTox) function improved significantly, HIV-1-associated CD8 T-cell skewing normalized, and the percentage of late-stage and major histocompatibility complex (MHC) class II expressing CD4 T-cells increased. Activated CD4+ CD38+ human leukocyte antigen (HLA)-DR+ T-cells declined, and costimulation shifted to coinhibition. DTH was unchanged. Maraviroc intensification, through antagonism of the cell surface molecule CCR5, favorably influences immune profiles of HIV-1+ patients, supporting its immunomodulatory use in HIV-1 infection and potentially in other immunologically relevant settings

Effects of recombinant human growth hormone on HIV-1-specific T-cell responses, thymic output and proviral DNA in patients on HAART: 48-week follow-up

Background: Efficacious immune-based therapy in treated chronic HIV-1 infection requires the induction of virus-specific CD4+ T cells and subsequent maturation and maintenance of specific memory CD8+ T cells. Concomitant daily administration of recombinant human growth hormone (rhGH) with highly active antiretroviral therapy (HAART) was used in chronically infected patients with lipodystrophy in an attempt to reconstitute these virus-specific T-cell responses. Methods: Individuals with chronic HIV-1 infection on HAART were enrolled on a randomized, double-blinded, placebo-controlled study to receive rhGH therapy. We assessed HIV-1-specific proliferative CD4+ and interferon-gamma (IFN-γ)-producing CD8+ T-cell responses, quantified thymic output and proviral HIV-1 DNA at the following time points: baseline; after 12 weeks of rhGH therapy; at 24 weeks, after randomization into three groups [placebo weeks 12-24 (Group A), alternate-day dosing weeks 12-24 (Group B), and twice-per-week dosing weeks 12-24 (Group C)]; and at 48 weeks after all patients had received HAART alone for the final 24 weeks. Results: We found significant increases in both proliferative CD4+ and IFN-γ-producing CD8+ HIV-1-specific T-cell responses after daily administration of rhGH. This increase was focused on HIV-1 Gag-specific T-cell responses. Following subsequent randomisation into different dosing regimens, HIV-1-specific proliferative CD4+ T-cell responses declined in patients receiving less frequent dosing of rhGH, while virus-specific IFN-γ-producing CD8+ T-cell responses were maintained for longer periods of time. There was no significant change in thymic output and the cell-associated HIV-1 DNA remained stable in most patients. An increased anti-HIV-1 Nef-specific CD4+ T-cell proliferative response was correlated to a decrease in proviral load, and an increased HIV-1 Gag-specific IFN-γ-producing CD8+ T-cell response correlated with an increase in proviral load. Conclusion: The implication of these data is that daily dosing of rhGH with HAART, in addition to improving HIV-1-associated lipodystrophy, may reverse some of the T-lymphocyte dysfunction seen in most treated HIV-1-positive patients, in a dose-dependent manner. Such immune-based therapeutic strategies used in treated, chronic HIV-1 infection may enable the induction of virus-specific CD4+ T cells essential for the subsequent kick-start and expansion of virus-specific CD8+ T cells. © 2008 Herasimtschuk et al; licensee BioMed Central Ltd

Are Long-Term Non-Progressors Very Slow Progressors? Insights from the Chelsea and Westminster HIV Cohort, 1988–2010

Define and identify long-term non-progressors (LTNP) and HIV controllers (HIC), and estimate time until disease progression. LTNP are HIV-1+ patients who maintain stable CD4+ T-cell counts, with no history of opportunistic infection or antiretroviral therapy (ART). HIC are a subset of LTNP who additionally have undetectable viraemia. These individuals may provide insights for prophylactic and therapeutic development. Records of HIV-1+ individuals attending Chelsea and Westminster Hospital (1988–2010), were analysed. LTNP were defined as: HIV-1+ for >7 years; ART-naïve; no history of opportunistic infection and normal, stable CD4+ T-cell counts. MIXED procedure in SAS using random intercept model identified long-term stable CD4+ T-cell counts. Survival analysis estimated time since diagnosis until disease progression. Subjects exhibiting long-term stable CD4+ T-cell counts with history below the normal range (<450 cells/µl blood) were compared to LTNP whose CD4+ T-cell count always remained normal. Within these two groups subjects with HIV-1 RNA load below limit of detection (BLD) were identified. Of 14,227 patients, 1,204 were diagnosed HIV-1+ over 7 years ago and were ART-naïve. Estimated time until disease progression for the 20% (239) whose CD4+ T-cell counts remained within the normal range, was 6.2 years (IQR: 2.0 to 9.6); significantly longer than 4.0 years (IQR: 1.0 to 7.3) for patients with historical CD4+ T-cell count below normal (Logrank chi-squared = 21.26; p<0.001). Within a subpopulation of 312 asymptomatic patients, 50 exhibited long-term stable CD4+ T-cell counts. Of these, 13 were LTNP, one of whom met HIC criteria. Of the remaining 37 patients with long-term stable low CD4+ T-cell counts, 3 controlled HIV-1 RNA load BLD. Individuals with stable, normal CD4+ T-cell counts progressed less rapidly than those with low CD4+ T-cell counts. Few LTNP and HIC identified in this and other studies, endorse the need for universal definitions to facilitate comparison