Functional Subsystems and Quantum Redundancy in Photosynthetic Light Harvesting

The Fenna-Matthews-Olson (FMO) antennae complex, responsible for light harvesting in green sulfur bacteria, consists of three monomers, each with seven chromophores. Here we show that multiple subsystems of the seven chromophores can transfer energy from either chromophore 1 or 6 to the reaction center with an efficiency matching or in many cases exceeding that of the full seven chromophore system. In the FMO complex these functional subsystems support multiple quantum pathways for efficient energy transfer that provide a built-in quantum redundancy. There are many instances of redundancy in nature, providing reliability and protection, and in photosynthetic light harvesting this quantum redundancy provides protection against the temporary or permanent loss of one or more chromophores. The complete characterization of functional subsystems within the FMO complex offers a detailed map of the energy flow within the FMO complex, which has potential applications to the design of more efficient photovoltaic devices

Circulating microRNAs in sera correlate with soluble biomarkers of immune activation but do not predict mortality in ART treated individuals with HIV-1 infection: A case control study

Introduction: The use of anti-retroviral therapy (ART) has dramatically reduced HIV-1 associated morbidity and mortality. However, HIV-1 infected individuals have increased rates of morbidity and mortality compared to the non-HIV-1 infected population and this appears to be related to end-organ diseases collectively referred to as Serious Non-AIDS Events (SNAEs). Circulating miRNAs are reported as promising biomarkers for a number of human disease conditions including those that constitute SNAEs. Our study sought to investigate the potential of selected miRNAs in predicting mortality in HIV-1 infected ART treated individuals. Materials and Methods: A set of miRNAs was chosen based on published associations with human disease conditions that constitute SNAEs. This case: control study compared 126 cases (individuals who died whilst on therapy), and 247 matched controls (individuals who remained alive). Cases and controls were ART treated participants of two pivotal HIV-1 trials. The relative abundance of each miRNA in serum was measured, by RTqPCR. Associations with mortality (all-cause, cardiovascular and malignancy) were assessed by logistic regression analysis. Correlations between miRNAs and CD4+ T cell count, hs-CRP, IL-6 and D-dimer were also assessed. Results: None of the selected miRNAs was associated with all-cause, cardiovascular or malignancy mortality. The levels of three miRNAs (miRs -21, -122 and -200a) correlated with IL-6 while miR-21 also correlated with D-dimer. Additionally, the abundance of miRs -31, -150 and -223, correlated with baseline CD4+ T cell count while the same three miRNAs plus miR- 145 correlated with nadir CD4+ T cell count. Discussion: No associations with mortality were found with any circulating miRNA studied. These results cast doubt onto the effectiveness of circulating miRNA as early predictors of mortality or the major underlying diseases that contribute to mortality in participants treated for HIV-1 infection

Development and Validation of a Risk Score for Chronic Kidney Disease in HIV Infection Using Prospective Cohort Data from the D:A:D Study

Ristola M. on työryhmien DAD Study Grp ; Royal Free Hosp Clin Cohort ; INSIGHT Study Grp ; SMART Study Grp ; ESPRIT Study Grp jäsen.Background Chronic kidney disease (CKD) is a major health issue for HIV-positive individuals, associated with increased morbidity and mortality. Development and implementation of a risk score model for CKD would allow comparison of the risks and benefits of adding potentially nephrotoxic antiretrovirals to a treatment regimen and would identify those at greatest risk of CKD. The aims of this study were to develop a simple, externally validated, and widely applicable long-term risk score model for CKD in HIV-positive individuals that can guide decision making in clinical practice. Methods and Findings A total of 17,954 HIV-positive individuals from the Data Collection on Adverse Events of Anti-HIV Drugs (D:A:D) study with >= 3 estimated glomerular filtration rate (eGFR) values after 1 January 2004 were included. Baseline was defined as the first eGFR > 60 ml/min/1.73 m2 after 1 January 2004; individuals with exposure to tenofovir, atazanavir, atazanavir/ritonavir, lopinavir/ritonavir, other boosted protease inhibitors before baseline were excluded. CKD was defined as confirmed (>3 mo apart) eGFR In the D:A:D study, 641 individuals developed CKD during 103,185 person-years of follow-up (PYFU; incidence 6.2/1,000 PYFU, 95% CI 5.7-6.7; median follow-up 6.1 y, range 0.3-9.1 y). Older age, intravenous drug use, hepatitis C coinfection, lower baseline eGFR, female gender, lower CD4 count nadir, hypertension, diabetes, and cardiovascular disease (CVD) predicted CKD. The adjusted incidence rate ratios of these nine categorical variables were scaled and summed to create the risk score. The median risk score at baseline was -2 (interquartile range -4 to 2). There was a 1: 393 chance of developing CKD in the next 5 y in the low risk group (risk score = 5, 505 events), respectively. Number needed to harm (NNTH) at 5 y when starting unboosted atazanavir or lopinavir/ritonavir among those with a low risk score was 1,702 (95% CI 1,166-3,367); NNTH was 202 (95% CI 159-278) and 21 (95% CI 19-23), respectively, for those with a medium and high risk score. NNTH was 739 (95% CI 506-1462), 88 (95% CI 69-121), and 9 (95% CI 8-10) for those with a low, medium, and high risk score, respectively, starting tenofovir, atazanavir/ritonavir, or another boosted protease inhibitor. The Royal Free Hospital Clinic Cohort included 2,548 individuals, of whom 94 individuals developed CKD (3.7%) during 18,376 PYFU (median follow-up 7.4 y, range 0.3-12.7 y). Of 2,013 individuals included from the SMART/ESPRIT control arms, 32 individuals developed CKD (1.6%) during 8,452 PYFU (median follow-up 4.1 y, range 0.6-8.1 y). External validation showed that the risk score predicted well in these cohorts. Limitations of this study included limited data on race and no information on proteinuria. Conclusions Both traditional and HIV-related risk factors were predictive of CKD. These factors were used to develop a risk score for CKD in HIV infection, externally validated, that has direct clinical relevance for patients and clinicians to weigh the benefits of certain antiretrovirals against the risk of CKD and to identify those at greatest risk of CKD.Peer reviewe

Role of Guanidyl Moiety in the Insertion of Arginine and Nα-Benzoyl-l-argininate Ethyl Ester Chloride in Lipid Membranes

Role of Guanidyl Moiety in the Insertion of Arginine and Nα-Benzoyl-l-argininate Ethyl Ester Chloride in Lipid Membranes AbstractFull Text HTMLHi-Res PDF[1247 KB]PDF w/ Links[216 KB]FiguresReferencesA. C. Fonseca‡, M. A. Frías†, A. M. Bouchet†, S. Jarmelo‡§, P. N. Simões‡, R. Fausto§, M. H. Gil‡, F. Lairion† and E. A. Disalvo*† Laboratory of Physical Chemistry of Lipid Membranes, Department of Analytical Chemistry and Physical Chemistry, Pharmacy and Biochemistry, University of Buenos Aires Junín 956 2° piso (1113), Buenos Aires, Argentina, Department of Chemical Engineering, University of Coimbra, Polo II, Pinhal de Marrocos, 3030-790 Coimbra, Portugal, and Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal J. Phys. Chem. B, 2010, 114 (17), pp 5946–5952 DOI: 10.1021/jp101007b Publication Date (Web): April 13, 2010 Copyright © 2010 American Chemical Society * Corresponding author. Phone: 54 11 39648249. Fax: 54 11 45083645. E-mail: [email protected]., † Department of Analytical Chemistry and Physical Chemistry, Pharmacy and Biochemistry, University of Buenos Aires Junín 956 2° piso (1113). , ‡ Department of Chemical Engineering, University of Coimbra. , § Department of Chemistry, University of Coimbra. AbstractGuanidyl moieties of both arginine (Arg) and Nα-benzoyl-l-argininate ethyl ester chloride (BAEE) are protonated in all environments studied, i.e., dry solid state, D2O solutions, and dry and hydrated lipids as suggested by DFT(B3LYP)/6-31+G(d,p) calculations. Arg and BAEE are able to insert in the lipid interphase of both DMPC and DOPC monolayers as revealed by the observed decrease in the membrane dipole potential they induce. The larger decrease in the dipole potential induced by BAEE, compared to Arg, can be explained partially by the higher affinity of the hydrophobic benzoyl and ethyl groups for the membrane phase, which allows an easier insertion of this molecule. FTIR studies indicate that the guanidyl moiety of Arg is with all probability facing the hydrophobic part of the lipids, whereas in BAEE this group is facing the water phase. Zeta potential measurements provide a direct evidence that Arg orients in the lipid interphase of phosphatidylcholine (PC) bilayers with the negative charged carboxylate group (−COO−) toward the aqueous phase