Effect of thermal annealing on the structural and optical properties of tris‐(8‐hydroxyquinoline)aluminum(III) (Alq3) films

Tris‐(8‐hydroxyquionoline)aluminum (Alq₃) was synthesized and coated on to a glass substrate using the dip coating method. The structural and optical properties of the Alq₃ film after thermal annealing from 50°C to 300°C in 50° steps was studied. The films have been prepared with 2 to 16 layers (42–324 nm). The thickness and thermal annealing of Alq₃ films were optimized for maximum luminescence yield. The Fourier transform infrared spectrum confirms the formation of quinoline with absorption in the region 700 ? 500/cm. Partial sublimation and decomposition of quinoline ion was observed with the Alq₃ films annealed at 300°C. The X‐ray diffraction pattern of the Alq₃ film annealed at 50°C to 150°C reveals the amorphous nature of the films. The Alq₃ film annealed above 150°C were crystalline nature. Film annealed at 150°C exhibits a photoluminescence intensity maximum at 512 nm when excited at 390 nm. The Alq₃ thin film deposited with 10 layers (220 nm) at 150°C exhibited maximum luminescence yield. Copyright © 2014 John Wiley & Sons, Ltd.     

Multiplex Real-Time PCR Assay Using TaqMan Probes for the Identification of Trypanosoma cruzi DTUs in Biological and Clinical Samples

Background

Trypanosoma cruzi has been classified into six Discrete Typing Units (DTUs), designated as TcI–TcVI. In order to effectively use this standardized nomenclature, a reproducible genotyping strategy is imperative. Several typing schemes have been developed with variable levels of complexity, selectivity and analytical sensitivity. Most of them can be only applied to cultured stocks. In this context, we aimed to develop a multiplex Real-Time PCR method to identify the six T. cruzi DTUs using TaqMan probes (MTq-PCR).

Methods/Principal Findings

The MTq-PCR has been evaluated in 39 cultured stocks and 307 biological samples from vectors, reservoirs and patients from different geographical regions and transmission cycles in comparison with a multi-locus conventional PCR algorithm. The MTq-PCR was inclusive for laboratory stocks and natural isolates and sensitive for direct typing of different biological samples from vectors, reservoirs and patients with acute, congenital infection or Chagas reactivation. The first round SL-IR MTq-PCR detected 1 fg DNA/reaction tube of TcI, TcII and TcIII and 1 pg DNA/reaction tube of TcIV, TcV and TcVI reference strains. The MTq-PCR was able to characterize DTUs in 83% of triatomine and 96% of reservoir samples that had been typed by conventional PCR methods. Regarding clinical samples, 100% of those derived from acute infected patients, 62.5% from congenitally infected children and 50% from patients with clinical reactivation could be genotyped. Sensitivity for direct typing of blood samples from chronic Chagas disease patients (32.8% from asymptomatic and 22.2% from symptomatic patients) and mixed infections was lower than that of the conventional PCR algorithm.

Conclusions/Significance

Typing is resolved after a single or a second round of Real-Time PCR, depending on the DTU. This format reduces carryover contamination and is amenable to quantification, automation and kit production.     

Antiproteinuric treatment reduces urinary loss of vitamin D-binding protein but does not affect vitamin D status in patients with chronic kidney disease

Vitamin D deficiency is common in chronic kidney disease (CKD). Increased urinary loss of vitamin D binding protein (VDBP), the main transporter of 25-hydroxyvitamin D(3) in the circulation, has been postulated to contribute to vitamin D deficiency in proteinuria. To test this hypothesis we analyzed urinary and plasma levels of VDBP, 25-hydroxyvitamin D(3) and 1,25-dihydroxyvitamin D(3) from proteinuric patients, before and after antiproteinuric interventions. We performed a post-hoc analysis of a clinical trial in CKD patients (n=13, creatinine clearance median 60 (range 25-177) ml/min) subjected to the following study periods: washout (no antiproteinuric treatment, 4 weeks), lisinopril 40mg QD (ACEi, 6 weeks), or indomethacin 75mg BID (NSAID, 4 weeks) in randomized sequence. Healthy subjects screened for donation (n=10) served as controls. Plasma and urine VDBP levels were measured by ELISA, 25-hydroxyvitamin D(3) levels by LC-MS and 1,25-dihydroxyvitamin D(3) levels by radioimmunoassay. In CKD patients urinary VDBP excretion was strongly increased (median (range) 5413 (155-211,027) μg/24h) as compared to healthy controls (64 (23-111) μg/24h, p<0.001). Both NSAID and ACEi significantly decreased urinary VDBP excretion, in proportion to proteinuria reduction. Plasma VDBP, 25-hydroxyvitamin D(3) and 1,25-dihydroxyvitamin D(3) levels, however, were similar between patients and controls and not affected by antiproteinuric intervention. Urinary VDBP excretion is markedly increased in proteinuria and responds to antiproteinuric treatment. Urinary VDBP loss is not associated with plasma VDBP or vitamin D(3) levels, suggesting that urinary loss of VDBP does not affect vitamin D status.     

Stability analysis of an artificial biomolecular oscillator with non-cooperative regulatory interactions

Oscillators are essential to fuel autonomous behaviours in molecular systems. Artificial oscillators built with programmable biological molecules such as DNA and RNA are generally easy to build and tune, and can serve as timers for biological computation and regulation. We describe a new artificial nucleic acid biochemical reaction network, and we demonstrate its capacity to exhibit oscillatory solutions. This network can be built in vitro using nucleic acids and three bacteriophage enzymes, and has the potential to be implemented in cells. Numerical simulations suggest that oscillations occur in a realistic range of reaction rates and concentrations.     

Epidemiological characteristics of American cutaneous leishmaniasis in an endemic region of the State of Bahia. III. Phlebotomine fauna

The phlebotomine fauna is highly varied in Três Bra?os, an endemic area of american cutaneous leishmaniasis, situated in the cacao growing region in the southeast of Bahia State, Brazil. Thirty spécies of the Lutzomyia genus were identified in 13,535 specimens collected between 1976 and 1984. Lutzomyia whitmani was the dominant species accounting for 99% of flies in the peridomicile and 97.5% of those caught in homes. In the forest the predominant species were Lu. ayrozai and Lu. yuilli. Lu. whitmani accounted for only 1.0% of the specimens examined. Lu. flaviscutellata, the proven vector of Leishmania mexicana amazonensis, was also collected in small numbers. Lu. wellcomei, a known vector of L. braziliensis braziliensis in the Serra dos Carajás, Pará, Brazil was not encountered in the Três Bra?os region where the parasite causing human infections is usually L.b. braziliensis. Although we have not encountered a natural infection with leishmanial promastigotes in 1,832 females of the various species examined, we discuss the probability that Lu. whitmani is the vector of L.b. braziliensis in the region maintaining transmission in dogs and man.     

Biogeography of Triatominae (Hemiptera: Reduviidae) in Ecuador: implications for the design of control strategies

Chagas disease control strategies strongly depend on the triatomine vector species involved in Trypanosoma cruzi transmission within each area. Here we report the results of the identification of specimens belonging to various species of Triatominae captured in Ecuador (15 species from 17 provinces) and deposited in the entomological collections of the Catholic University of Ecuador (Quito), Instituto Oswaldo Cruz (Brazil), the Natural History Museum London (UK), the London School of Hygiene and Tropical Medicine (UK), the National Institute of Hygiene (Quito), and the Vozandes Hospital (Quito). A critical review of published information and new field records are presented. We analysed these data in relation to the life zones where triatomines occur (11 life zones, excluding those over 2,200 m altitude), and provide biogeographical maps for each species. These records are discussed in terms of epidemiological significance and design of control strategies. Findings relevant to the control of the main vector species are emphasised. Different lines of evidence suggest that Triatoma dimidiata is not native to Ecuador-Peru, and that synanthropic populations of Rhodnius ecuadoriensis in southern Ecuador-northern Peru might be isolated from their sylvatic conspecifics. Local eradication of T. dimidiata and these R. ecuadoriensis populations might therefore be attainable. However, the presence of a wide variety of native species indicates the necessity for a strong longitudinal surveillance system.     

Cold-acclimation limits low temperature induced photoinhibition by promoting a higher photochemical quantum yield and a more effective PSII restoration in darkness in the Antarctic rather than the Andean ecotype of Colobanthus quitensis Kunt Bartl (Cariophyllaceae)

ABSTRACT: BACKGROUND: Ecotypes of Colobanthus qutensis Kunt Bartl (Cariophyllaceae) from Andes Mountains andMaritime Antarctic grow under contrasting photoinhibitory conditions, reaching differentialcold tolerance upon cold acclimation. Photoinhibition depends on the extent of photodamageand recovery capability. We propose that cold acclimation increases resistance to lowtemperature-induced photoinhibition, limiting photodamage and promoting recovery undercold. Therefore, the Antarctic ecotype (cold hardiest) should be less photoinhibited and havebetter recovery from low-temperature-induced photoinhibition than the Andean ecotype. Bothecotypes were exposed to cold induced photoinhibitory treatment (PhT). Photoinhibition andrecovery of photosystem II (PSII) was followed by fluorescence, CO2 exchange, andimmunoblotting analyses. RESULTS: The same reduction (25%) in maximum PSII efficiency (Fv/Fm) was observed in both coldacclimated(CA) and non-acclimated (NA) plants under PhT. A full recovery was observed inCA plants of both ecotypes under dark conditions, but CA Antarctic plants recover faster thanthe Andean ecotype.Under PhT, CA plants maintain its quantum yield of PSII, while NA plants reduced itstrongly (50% and 73% for Andean and Antarctic plants respectively). Cold acclimationinduced the maintenance of PsaA and Cyt b6/f and reduced a 41% the excitation pressure inAntarctic plants, exhibiting the lowest level under PhT. Cold acclimation decreasessignificantly NPQs in both ecotypes, and reduce chlorophylls and D1 degradation in Andeanplants under PhT.NA and CA plants were able to fully restore their normal photosynthesis, while CA Antarcticplants reached 50% higher photosynthetic rates after recovery, which was associated toelectron fluxes maintenance under photoinhibitory conditions. CONCLUSIONS: Cold acclimation has a greater importance on the recovery process than on limitingphotodamage. Cold acclimation determined the kinetic and extent of recovery process underdarkness in both C. quitensis ecotypes. The greater recovery of PSII at low temperature in theAntarctic ecotype was related with its ability to maintain PsaA, Cyt b6/f and D1 protein afterphotoinhibitory conditions. This is probably due to either a higher stability of thesepolypeptides or to the maintenance of their turnover upon cold acclimation. In both cases, itis associated to the maintenance of electron drainage from the intersystem pool, whichmaintains QA more oxidized and may allow the synthesis of ATP and NADPH necessariesfor the regeneration of ribulose 1,5-bisphosphate in the Calvin Cycle. This could be a keyfactor for C. quitensis success under the harsh conditions and the short growing period in theMaritime Antarctic.