Selenite (IV) and selenate (VI) uptake and accumulation capacity of Lemna minor L. from an aquatic medium.

The uptake of sodium selenite (Se(IV)) and sodium selenate (Se(VI)) from aqueous medium by Lemna minor L. and the influence of different Se concentrations on its growth, morphological and ultrastructural characteristics were studied. L. minor was grown at different concentrations (1, 3, 5 and 10 mg L-1) of Se(IV) and Se(IV). The Se(IV) concentration in the plant tissue ranged between 77.7 (± 4.3) to 453 (± 0) mg kg-1 DW. The Se(VI) concentration in plant tissues ranged between 117 (± 11) to 417 (± 2) mg kg-1 DW. The highest bioconcentration factor for Se(VI) was 127 (± 7) at 3 mg/L, with a Se removal efficiency of 44%. For Se(IV), the highest bioconcentration factor was 77.7 (± 4.3) at 1 mg L-1, which had a Se removal efficiency of 23%. Growth of L. minor was suppressed at 10 mg L-1 Se in both forms. The addition of Se promoted the formation of starch granules in L. minor which occupied a chloroplast area of 74% for Se(IV) and 77% for Se(VI). The efficient uptake of both Se forms by L. minor indicates the potential application of this species for phytoremediation of Se laden wastewaters and its use as an alternative feedstock in biofuel production.

Correction: How much (ATP) does it cost to build a trypanosome? A theoretical study on the quantity of ATP needed to maintain and duplicate a bloodstream-form Trypanosoma brucei cell.

[This corrects the article DOI: 10.1371/journal.ppat.1011522.].

How much (ATP) does it cost to build a trypanosome? A theoretical study on the quantity of ATP needed to maintain and duplicate a bloodstream-form Trypanosoma brucei cell.

ATP hydrolysis is required for the synthesis, transport and polymerization of monomers for macromolecules as well as for the assembly of the latter into cellular structures. Other cellular processes not directly related to synthesis of biomass, such as maintenance of membrane potential and cellular shape, also require ATP. The unicellular flagellated parasite Trypanosoma brucei has a complex digenetic life cycle. The primary energy source for this parasite in its bloodstream form (BSF) is glucose, which is abundant in the host's bloodstream. Here, we made a detailed estimation of the energy budget during the BSF cell cycle. As glycolysis is the source of most produced ATP, we calculated that a single parasite produces 6.0 x 1011 molecules of ATP/cell cycle. Total biomass production (which involves biomass maintenance and duplication) accounts for ~63% of the total energy budget, while the total biomass duplication accounts for the remaining ~37% of the ATP consumption, with in both cases translation being the most expensive process. These values allowed us to estimate a theoretical YATP of 10.1 (g biomass)/mole ATP and a theoretical [Formula: see text] of 28.6 (g biomass)/mole ATP. Flagellar motility, variant surface glycoprotein recycling, transport and maintenance of transmembrane potential account for less than 30% of the consumed ATP. Finally, there is still ~5.5% available in the budget that is being used for other cellular processes of as yet unknown cost. These data put a new perspective on the assumptions about the relative energetic weight of the processes a BSF trypanosome undergoes during its cell cycle.

Selenium recovery from wastewater by the green microalgae Chlorella vulgaris and Scenedesmus sp.

Selenium (Se) is an important element for many living organisms and its supplementation may be needed in food, feed, and soil to make up for its deficiency. At the same time, high selenium concentrations can harm the environment, thus its management in sewage and the study of its removal from waste streams are important. Microalgae-based systems may be used for wastewater treatment and nutrients recovery, while producing biomass for bioproducts or bioenergy. In this study, Chlorella vulgaris and Scenedesmus sp. grown in urban wastewater with different selenium concentrations (50-1000 µg Se/L) were evaluated for their resistance and selenium removal/recovery efficiency. Chlorella vulgaris and Scenedesmus sp. were able to remove up to 43 and 52 % of Se from wastewater, respectively. Chlorella vulgaris accumulated up to 323 mgSe/kg DW (in urban wastewater with 1000 µg Se/L). The Se-rich biomass produced may be applied to the supplementation of animal feed or used for biofortification of crops.

Renal safety of coformulated tenofovir/emtricitabine vs other nucleoside analogues in combination therapy in antiretroviral-naive patients aged 50 years or older in Spain: The TRIP study.

OBJECTIVES: Our aim is to describe the impact of emtricitabine (FTC)/tenofovir (TDF) versus other nucleoside reverse transcriptase inhibitor (NRTIs)-based regimens on renal function of human immunodeficiency virus (HIV) naïve patients >50 years old who started combination antiretroviral therapy (cART). DESIGN: National, retrospective cohort analysis of patients >50 years old when they started cART (January 1, 2006-December 31, 2009). METHODS: We compared renal safety (changes in estimated glomerular filtration rate [eGFR] during the first year, and time to renal events during 4 years of follow-up) in FTC/TDF versus non-FTC/TDF users. Among FTC/TDF users, we compared protease inhibitors vs non-nucleoside reverse transcriptase inhibitors and Lopinavir/ritonavir vs Efavirenz. RESULTS: We included 103 patients: median age: 54.9 years, 84% males, median CD4 count 247 cells/µl, median viral load 4.7 log; median follow up 18 months (max: 48 months); 73 started with FTC/TDF and 30 with other NRTIs. Change in eGFR was significantly worse for ritonavir-boosted lopinavir (LPV/r) vs efavirenz (EFV) users in the FTC/TDF group (71.2 vs 98.9 ml/min/1.73 m(2) at month 12, P < 0.05). The risk of renal events (progression to an Chronic Kidney Disease Epidemiology Collaboration value < 60 ml/min/1.73 m(2) in subjects with baseline values >60) was comparable for FTC/TDF users and non users, but was higher and almost significant for LPV/r as compared to EFV users in the FTC/TDF group (adjusted hazard ratio 6.1, 95% CI 0.8-45.5). CONCLUSIONS: In our study with a population of HIV infected subjects ≥ 50 years old, renal safety was similar for FTC/TDF and other NRTI-based regimens, but worse for LPV/r as compared to other regimens.

PURIFICACIÓN DEL ANTÍGENO 38 kDa DE Mycobacterium tuberculosis Y SU POTENCIAL USO EN DIAGNÓSTICO MEDIANTE INMUNOSENSORES PIEZOELÉCTRICOS / Mycobacterium tuberculosis 38 kDa Antigen Purification and Potential Diagnostic Use by Piezoelectric Immunosensors

Un paso crucial en el desarrollo de un inmunosensor piezoeléctrico para la detección de tuberculosis (TB), es la selección y obtención de los inmunoreactivos empleados en el inmunoensayo y la estrategia para la biofuncionalización del transductor. Diversos estudios han reportado el uso del antígeno proteico 38kDa (Ag38kDa) de Mycobacterium tuberculosis (Mtb) como un buen biomarcador de la enfermedad y el cumplimiento de las características físicas y bioquímicas para ser inmovilizado por monocapas autoensambladas (SAMs), en la superficie del electrodo de oro de cristales piezoeléctricos. Un inmunosensor piezoeléctrico desarrollado a partir de un antígeno nativo purificado de Mtb podría ser un método alternativo simple para la detección de Mtb con ventajas de rapidez y reusabilidad, contribuyendo al control y el tratamiento oportuno de la enfermedad. En este estudio se presenta el proceso de purificación del Ag38kDa a partir de proteínas de secreción filtradas de cultivo (CFP) de Mtb para ser usado como inmunoreactivo con potencial aplicación en la detección de Mtb con inmunosensores piezoeléctricos. Se obtuvieron cristales funcionalizados mediante la técnica modificada de monocapas autoensambladas (SAMs), con el antígeno nativo purificado y CFP. Las superficies biofuncionalizadas fueron caracterizadas cualitativamente con microscopía de fuerza atómica (AFM) para validar las condiciones de optimización del protocolo de inmovilización con antígenos de secreción de Mtb. Estos cristales modificados pueden ser acoplados a un sistema de caracterización de un inmunosensor piezoeléctrico para la detección de Mtb mediante un inmunoensayo competitivo directo.

The selection and procurance of the immunoreagents used in the immunoassay and biofunctionalisation transducer strategy, are a key in the piezoelectric immunosensor development for the detection of tuberculosis (TB). Many have reported the use of 38kDa protein antigen (Ag38kDa) from Mycobacterium tuberculosis (Mtb) such as good biomarker of TB disease and compliance with physical and biochemical characteristics to be immobilized by self-assembled monolayers (SAMs), in the gold electrode of piezoelectrics crystals surfaces. A piezoelectric immunosensor developed from purified native antigens of Mtb may be an alternative simple method for detection of Mtb with speed and reusable advantages, contributing to the control and early treatment of disease. In this paper, the purification process of Ag38kDa Mtb from secretory proteins filtered culture (CFP) from Mtb is presented as an immunoreactive with potential application in the detection of Mtb by piezoelectric immunosensors. Functionalized crystals were obtained by using the modified self-assembled monolayers (SAMs) technique, with purified native antigen and CFP. The functionalized surfaces were qualitatively characterized using atomic force microscopy (AFM) in order to validate the immobilization protocol optimal conditions for secretion antigens from Mtb. These modified crystals may be coupled to piezoelectric immunosensor characterization system for detecting of Mtb by a direct competition immunoassay.

HIV testing policies for migrants and ethnic minorities in EU/EFTA Member States.

BACKGROUND: In the context of an European Centre for Disease Prevention and Control (ECDC) research project, our objective was to describe current recommendations regarding HIV testing and counselling targeting migrants and ethnic minorities in the European Union/European Economic Area/European Free Trade Association (EU/EEA/EFTA) Member States. METHODS: An on-line survey was conducted among 31 EU/EEA/EFTA Member States. The survey inquired on the existence of specific HIV testing and counselling recommendations or policies for migrants and/or ethnic minorities and the year of their publication. Additionally, we performed a review of national recommendations, guidelines or any other policy documents retrieved from an Internet search through the different countries' competent bodies. RESULTS: Twenty-nine (94%) country representatives responded the survey, and 28 documents from 27 countries were identified. National guidelines on HIV testing are heterogeneous and tailored, according to the epidemiological situation. Twenty-two countries identify migrants and four countries identify ethnic minorities as particularly vulnerable to HIV. Sixteen countries explicitly recommend offering an HIV test to migrants/ethnic minorities. Guidelines especially target people originating from HIV endemic countries, and benefits of HIV early detection are highlighted. HIV testing is not mandatory in any country, but some countries overtly facilitate this practice. CONCLUSION: Benefits of HIV testing in migrants and ethnic minorities, at both individual and community levels are recognized by many countries. In spite of this, not all countries identify the need to test these groups.

Response to HAART in treatment-naive HIV-infected patients with a prior diagnosis of tuberculosis or other opportunistic infections.

We aimed to evaluate immunological, virological and clinical response to HAART, as well as all-cause mortality, in treatment-naive patients with a diagnosis of tuberculosis (TB) in the prior 6 months, compared to subjects with another AIDS-defining illness (ADI) or event-free individuals in an open, prospective and multicenter hospital-based cohort of HIV-infected naive adults (2004-2008). All cause mortality rates were calculated by Cox regression models. Among 4407 patients, 2400 (54.5%) started HAART: 110 (4.6%) had had previous TB and 414 (17.3%) another ADI. Median time from TB diagnosis to inititation of HAART was 53 days (IQR: 25.75-83.25), and for other ADI was 22 days (IQR: 8-42). Overall, 151 (6.3%) patients developed a new ADI during follow-up; 63% reached virological suppression and 69.4% had increases of ≥50 CD4+/µl, at 6 months. No statistically significant differences were found according to a previous history of TB or another ADI. Overall, 85 subjects died in 4031 person-years of follow-up with a mortality rate of 2.1 (95%CI: 1.7-2.6). When compared to subjects who started HAART in the absence of a previous ADI (HR 1), a prior diagnosis of an ADI other than TB was significantly associated with an increased risk of death. (HR 1.6; 95%CI: 1.1-2.3), but not a diagnosis of TB (HR 1.15; 95%CI: 0.5-2.5). In conclusion, a previous diagnosis of TB or another ADI before HAART did not compromise short-term virological and immunological response to treatment. A prior diagnosis of an ADI different to TB significantly increased all cause mortality.

Physiological role and potential clinical interest of mycobacterial pigments.

The production of pigments by bacterial colonies has sparked interest among bacteriologists since the 19th century, whether for taxonomy or, in the case of carotenoids for their association with antibiotics resistance. Mycobacteria have gained a very special place in the bacterial world due to their clinical importance. Alone, Mycobacterium tuberculosis is responsible for about two million deaths annually worldwide making tuberculosis one of the most influential diseases in the history of mankind. Almost half of the Nontuberculous Mycobacteria species identified are associated with opportunistic infections in animals and humans. Mycobacterial pigmentary characteristics started to be documented about 80 years ago; but to date, their main use has been only for limited taxonomic and identification purposes. While mycobacterial pigments, especially carotenoids have been clearly associated with cellular photoprotection and survival, the regulation of their production and their physiological role have been largely unstudied. Recent advances in deciphering mycobacterial genomes and characterization of carotenoid synthesis genes, combined with an urgent need for innovative approaches to understand Mycobacterium tuberculosis pathogenic properties open new avenues for exciting research opportunities that might lead to new therapeutic strategies against a devastating secular disease.

Delayed diagnosis of HIV infection in a multicenter cohort: prevalence, risk factors, response to HAART and impact on mortality.

To study the prevalence of Delayed HIV Diagnosis (DHD) and its associated risk factors, to evaluate the effect of DHD on virological and immunological responses to HAART and to estimate the impact of DHD on all-causes mortality. Prospective cohort of 2, 564 HIV-positive HAART-naïve subjects attending 19 hospitals in Spain, 2004-2006. Estimations were made by logistic regression and survival analyses by Cox regression models. Prevalence of DHD was 37.3% (35.0-39.6). DHD was related to low educational level (OR:1.31, 95% CI:1.0-1.7). Compared to men who have sex with men (MSM), DHD was more frequent in heterosexuals (OR:1.9 95% CI:1.5-2.5) and injection drug users (IDUs) (OR:2.0 95% CI:1.5-2.8). An interaction between age and sex was found. Although risk of having DHD did not increase after age 30 in women, it increased linearly with age in men. No differences in virological (OR 1.2 95% CI: 0.8-1.8) and CD4 T cell (OR 1.1 95% CI: 0.7-1.8) responses to HAART were seen. The adjusted hazard ratio for death in patients with DHD was 5.2, (95% CI: 1.9-14.5). DHD is very common, especially in older men, heterosexuals and IDUs. Although we did not find differences in virological and immunological responses to HAART, we did observe higher mortality in people with DHD. Increased efforts to early diagnose HIV infection are urgently needed.