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A Complementary Mechanism of Bacterial mRNA Translation Inhibition by Tetracyclines
No full textWe are very thankful to Marcos Milla for donating equipment that was used in this study and others. We particularly thank Andrey Konevega and his team for providing the tRNAs that were used in this study. Also, we would like to thank all lab members of the Mil?n and Quiliano groups for their help, support, and fantastic working atmosphere. Funding. This work was supported by grants from the Peruvian Fondo Nacional de Desarrollo Cient?fico, Tecnol?gico y de Innovaci?n Tecnol?gica (154-2017-FONDECYT) and (036-2019-FONDECYT-BM-INC.INV) to PM and (406-2019-FONDECYT) to MQ and the Inn?vate Per? program (297-InnovatePeru-2016) to PM. Funding for open access was provided by the Universidad Peruana de Ciencias Aplicadas (C-014-2020).Tetracycline has positively impacted human health as well as the farming and animal industries. Its extensive usage and versatility led to the spread of resistance mechanisms followed by the development of new variants of the antibiotic. Tetracyclines inhibit bacterial growth by impeding the binding of elongator tRNAs to the ribosome. However, a small number of reports indicated that Tetracyclines could also inhibit translation initiation, yet the molecular mechanism remained unknown. Here, we use biochemical and computational methods to study how Oxytetracycline (Otc), Demeclocycline (Dem), and Tigecycline (Tig) affect the translation initiation phase of protein synthesis. Our results show that all three Tetracyclines induce Initiation Factor IF3 to adopt a compact conformation on the 30S ribosomal subunit, similar to that induced by Initiation Factor IF1. This compaction was faster for Tig than Dem or Otc. Furthermore, all three tested tetracyclines affected IF1-bound 30S complexes. The dissociation rate constant of IF1 in early 30S complexes was 14-fold slower for Tig than Dem or Otc. Late 30S initiation complexes (30S pre-IC or IC) exhibited greater IF1 stabilization by Tig than for Dem and Otc. Tig and Otc delayed 50S joining to 30S initiation complexes (30S ICs). Remarkably, the presence of Tig considerably slowed the progression to translation elongation and retained IF1 in the resulting 70S initiation complex (70S IC). Molecular modeling of Tetracyclines bound to the 30S pre-IC and 30S IC indicated that the antibiotics binding site topography fluctuates along the initiation pathway. Mainly, 30S complexes show potential contacts between Dem or Tig with IF1, providing a structural rationale for the enhanced affinity of the antibiotics in the presence of the factor. Altogether, our data indicate that Tetracyclines inhibit translation initiation by allosterically perturbing the IF3 layout on the 30S, retaining IF1 during 70S IC formation, and slowing the transition toward translation elongation. Thus, this study describes a new complementary mechanism by which Tetracyclines may inhibit bacterial protein synthesis. © Copyright © 2021 Barrenechea, Vargas-Reyes, Quiliano and Milón.Consejo Nacional de Ciencia, Tecnología e Innovación Tecnológica - Concyte
Colorimetry analysis of coat color and its relationship with fiber traits in alpacas
No full textThis research was partially funded by CONCYTEC-FONDECYT under the call for proposals E038-01 with contract number: 029-2019-FONDECYT-BM-INC.INV. BOKU- University of Natural Resources and Life Sciences, Vienna kindly provided the chromameter.Addressing the improvement of the textile characteristics is currently required in natural color production of alpaca fiber. This study analyses the possibility of implementing a genetic improvement program aiming to reduce the fiber diameter and the percentage of medullation in natural colors under the incomplete definition of the natural colors of alpaca fiber. The study considers color determination analysis in three separate steps. The first step aimed at finding the values of lightness (L*), red/green axis (a*), yellow/blue axis (b*) of three-dimensional space of color and chroma (C*ab), tone (h*ab) and color difference (?E) with mathematical models for the description of the coat color. The second analysis is aimed at estimating genetic parameters of color traits and their correlation with fiber traits (fiber diameter, standard deviations and percentage of medullation – PM). The third step was to determine the potential selection criteria of breeding animals based on the parameters provided by a three-dimensional space values regarding the coat color assignment in alpacas. The colorimetric data were taken using a Chroma meter device analyzing 3 008 records from Huacaya type alpacas, collected between 2018 and 2019. In the first objective of the study, the color traits were subjected to a principal component analysis. The analysis of variance components and the estimation of genetic parameters were carried out using a restricted maximum likelihood procedure. The discriminant analysis was used for the correct assignment of the coat color. The principal component analysis results showed that the L*, a*, b*, h*ab and ?E values can be grouped into two Principal Components (PC) to describe the color, where the L* value is mainly distributed in PC2, b* is distributed in PC1, while a* is distributed in both components. The heritabilities found were 0.144, 0.128, 0.151, 0.104 and 0.152 for L*, a*, b*, PC1 and PC2. The relevant genetic correlations were between L*-PM (?0.557) and b*-PM (?0.622). The discriminant analysis showed a high percentage of correct assignment in white (99.15%) and black (99.19%) coat colors for Huacaya type alpacas, while for the intermediate colors, the accuracy was lower. The three analyses showed that there is no pure natural color, but a range of color variation. It is better to use the values of the three-dimensional space and within them, the values of L* and b* are potential selection criteria to be included in a genetic improvement program. © 2021 The AuthorsConsejo Nacional de Ciencia, Tecnología e Innovación Tecnológica - Concyte
Current practices in missing data handling for interrupted time series studies performed on individual-level data: A scoping review in health research
No full textThis study was funded by the National Institute for Health Research (NIHR) School for Primary Care Research, project number 444. JCB was sponsored by FONDECYT- CONCYTEC (grant contract number 231-2015- FONDECYT). TPM, TMP and JRC were supported by the Medical Research Council (grant numbers MC_UU_12023/ 21 and MC_UU_12023/29). The study sponsors only had a funding role in this research. Thus, the researchers worked with total independence from their sponsors.Objective: Missing data can produce biased estimates in interrupted time series (ITS) analyses. We reviewed recent ITS investigations on health topics for determining 1) the data management strategies and statistical analysis performed, 2) how often missing data were considered and, if so, how they were evaluated, reported and handled. Study Design and Setting: This was a scoping review following standard recommendations from the PRISMA Extension for Scoping Reviews. We included a random sample of all ITS studies that assessed any intervention relevant to health care (eg, policies or programmes) with individual-level data, published in 2019, with abstracts indexed on MEDLINE. Results: From 732 studies identified, we finally reviewed 60. Reporting of missing data was rare. Data aggregation, statistical tools for modelling population-level data and complete case analyses were preferred, but these can lead to bias when data are missing at random. Seasonality and other time-dependent confounders were rarely accounted for and, when they were, missing data implications were typically ignored. Very few studies reflected on the consequences of missing data. Conclusion: Handling and reporting of missing data in recent ITS studies performed for health research have many shortcomings compared with best practice. © 2021 Bazo-Alvarez et al.Fondo Nacional de Desarrollo Científico y Tecnológico - Fondecy
Differentiating nanomaghemite and nanomagnetite and discussing their importance in arsenic and lead removal from contaminated effluents: A critical review
No full textThe authors thank the Fondo Nacional de Desarrollo Cient?fico, Tecnol?gico y de Inno-vaci?n Tecnol?gica (PROCIENCIA-CONCYTEC), project number: 177-2020-FONDECYT (PROCIEN-CIA), project CLEAN NANOMAGNETIC. The APC was funded by PROCIENCIA. Acknowledgments: Edson C. Passamani is also thankful to FAPES and CNPq for their financial support in the infrastructure of Ufes?s laboratory under his supervision. We finally thank Jean-Marc Greneche for supporting us with the in-field M?ssbauer measurement of NPEDTA samples.Arsenic and lead heavy metals are polluting agents still present in water bodies, including surface (lake, river) and underground waters; consequently, the development of new adsorbents is necessary to uptake these metals with high efficiency, quick and clean removal procedures. Magnetic nanoparticles, prepared with iron-oxides, are excellent candidates to achieve this goal due to their ecofriendly features, high catalytic response, specific surface area, and pulling magnetic response that favors an easy removal. In particular, nanomagnetite and maghemite are often found as the core and primary materials regarding magnetic nanoadsorbents. However, these phases show interesting distinct physical properties (especially in their surface magnetic properties) but are not often studied regarding correlations between the surface properties and adsorption applications, for instance. Thus, in this review, we summarize the main characteristics of the co-precipitation and thermal decomposition methods used to prepare the nano-iron-oxides, being the co-precipitation method most promising for scaling up processes. We specifically highlight the main differences between both nano-oxide species based on conventional techniques, such as X-ray diffraction, zero and in-field Mössbauer spectroscopy, X-ray photoelectron spectroscopy, X-ray absorption spectroscopy, and X-ray magnetic circular dichroism, the latter two techniques performed with synchrotron light. Therefore, we classify the most recent magnetic nanoadsorbents found in the literature for arsenic and lead removal, discussing in detail their advantages and limitations based on various physicochemical parameters, such as temperature, competitive and coexisting ion effects, i.e., considering the simultaneous adsorption removal (heavy metal–heavy metal competition and heavy metal–organic removal), initial concentration, magnetic adsorbent dose, adsorption mechanism based on pH and zeta potential, and real water adsorption experiments. We also discuss the regeneration/recycling properties, after-adsorption physicochemical properties, and the cost evaluation of these magnetic nanoadsorbents, which are important issues, but less discussed in the literature. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.Consejo Nacional de Ciencia, Tecnología e Innovación Tecnológica - Concyte
Evaluation and selection of biochars and hydrochars derived from agricultural wastes for the use as adsorbent and energy storage materials
No full textThe utilization of unconventional agricultural wastes to obtain new porous carbonaceous materials, at mild pyrolysis temperatures and without complex procedures, for either water treatment and energy storage applications is important from the economic and environmental perspective. In this study, biochars and hydrochars were prepared from banana rachis, cocoa pod husks, and rice husks at 600 °C-2 h, under nitrogen flux. The prepared materials were characterized to better understand how their morphological, textural, physical-chemical and/or structural properties correlate with their methylene blue (MB) adsorption capacities. The material with the best properties (mainly SBET > 800 m2/g) and MB adsorption capacity was a novel biochar prepared from banana rachis (BW-BC). This novel material was selected for additional kinetics and equilibrium adsorption tests for lead (Pb) along with its energy storage capacity. In equilibrium test, the novel biochar reached a maximum adsorption capacity for methylene blue of 243.4 mg/g and the highest adsorption capacity for Pb(II) of 179.7 mg/g. In the kinetic adsorption test, the equilibrium adsorption value for methylene blue was 150.4 mg/g and that for Pb(II) was 159.6 mg/g. Most importantly, the performance of the BW-BC material for energy storage in supercapacitors surpassed that of the commercial activated carbon YP50F, reaching specific energy values of 6.66 and 8.52 Wh/kg in acidic and neutral electrolytes, respectively. Among the evaluated hydrochar and biochars derived of agrowastes, the biochar prepared from banana rachis showed the best properties, being potentially useful as adsorbent or as an electrode material for energy storage. © 2021 Elsevier LtdThe authors would like to thank Universidad Nacional de Tumbes (CANON Projects) and Peruvian National Council for Science and Technology ( CONCYTEC ) (Contract N° 024–2016-FONDECYT and Contract N ° 160–2018-FONDECYT) for financial support of this project. The Institute of Environmental Technology – Excellent Research (No. CZ.02.1.01/0.0/0.0/16_019/ 0000853) and the ESF in “Science without borders” project, reg. nr. CZ.02.2.69/0.0/0.0/16_027/0008463 within the Operational Program Research, Development and Education were thanked. D.R. Lobato-Peralta would like to thank the National Council of Science and Technology ( CONACYT ) for the grant for his Ph.D. studies and the projects IG100217 PAPIIT-DGAPA and 279953 from CONACYT. Thanks to Eber Herrera who participated in the experimental work
High-resolution marine data and transient simulations support orbital forcing of ENSO amplitude since the mid-Holocene
No full textThis research has been supported by the JPI-Belmont project PACMEDY (via grant ANR-15-JCLI-0003-01 for MC, PB, ME, OM, TC, and BT). MC, JC, DO, RSG, AP, and PR acknowledge funding from Concejo Nacional de Ciencia y Tecnologia de Peru (grant n° 007-2017-FONDECYT , grant n° 034-2019-FONDECYT-BM ). SPH acknowledges funding from the ERC-funded project GC2.0 Global Change 2.0: Unlocking the past for a clearer future, grant number 694481 and from the JPI-Belmont project PACMEDY (via NERC ). The distribution and analyses of the transient Holocene simulations with the IPSL model benefit from the Institut Pierre Simon Laplace Climate Modeling Centre Infrastructure supported by ANR “Investissements d'avenir” program ANR-11-IDEX-0004-17-EURE-0006 .Lack of constraint on spatial and long-term temporal variability of the El Niño southern Oscillation (ENSO) and its sensitivity to external forcing limit our ability to evaluate climate models and ENSO future projections. Current knowledge of Holocene ENSO variability derived from paleoclimate reconstructions does not separate the role of insolation forcing from internal climate variability. Using an updated synthesis of coral and bivalve monthly resolved records, we build composite records of seasonality and interannual variability in four regions of the tropical Pacific: Eastern Pacific (EP), Central Pacific (CP), Western Pacific (WP) and South West Pacific (SWP). An analysis of the uncertainties due to the sampling of chaotic multidecadal to centennial variability by short records allows for an objective comparison with transient simulations (mid-Holocene to present) performed using four different Earth System models. Sea surface temperature and pseudo-?18O are used in model-data comparisons to assess the potential influence of hydroclimate change on records. We confirm the significance of the Holocene ENSO minimum (HEM) 3-6ka compared to low frequency unforced modulation of ENSO, with a reduction of ENSO variance of ?50 % in EP and ?80 % in CP. The approach suggests that the increasing trend of ENSO since 6ka can be attributed to insolation, while models underestimate ENSO sensitivity to orbital forcing by a factor of 4.7 compared to data, even when accounting for the large multidecadal variability. Precession-induced change in seasonal temperature range is positively linked to ENSO variance in EP and to a lesser extent in other regions, in both models and observations. Our regional approach yields insights into the past spatial expression of ENSO across the tropical Pacific. In the SWP, today under the influence of the South Pacific Convergence Zone (SPCZ), interannual variability was increased by ?200 % during the HEM, indicating that SPCZ variability is independent from ENSO on millennial time scales. © 2021 The AuthorsConsejo Nacional de Ciencia, Tecnología e Innovación Tecnológica - Concyte
Inhibitory activity against ?-amylase and ?-glucosidase by phenolic compounds of quinoa (Chenopodium quinoa Willd.) and cañihua (Chenopodium pallidicaule Aellen) from the Andean region of Peru
No full textThis study was funded by a grant from the National Fund for Scientific, Technological Development and Technological Innovation (FONDECYT) of the National Council of Science, Technology and Technological Innovation (CONCYTEC) of Peru, Contract N° 171-2015-FONDECYT.Background: Chenopodium quinoa Willd. and Chenopodium pallidicaule Aellen are grains from the Andean region of Peru, which in addition to having a high nutritional value, have health-promoting properties related to the prevention of chronic diseases such as diabetes. Objetive: The present study aimed to identify phenolic compounds associated with an inhibition of carbohydrate hydrolyzing enzymes associated with type 2 diabetes. Material and Methods: Two varieties of quinoa and two varieties of cañihua from the Puno Region in Peru, were evaluated. Total phenolics, total flavonoids, identification of phenolic compounds and antioxidant activity in vitro were measured by Folin-Ciocalteu assay, aluminum chloride colorimetric method, HPLC-DAD and DPPH radical scavenging assay, respectively. In vitro hypoglycemic activity was evaluated through the inhibition of the ?-amylase and ?-glucosidase enzymes. Results: Gallic acid, rutin and chlorogenic acid were identified by HPLC-DAD in the varieties of quinoa and cañihua. The latter showed significantly higher levels of chlorogenic acid compared to quinoa varieties (p<0.05). Both Andean grains exhibited inhibition of key-enzymes linked to type 2 diabetes, presenting IC50 values of 7.99 to 34.05 and of 8.07 to 1158 µg/mL for ?-amylase and ?-glucosidase, respectively. Total phenolics, total flavonoids, DPPH radical scavenging assay, gallic acid and chlorogenic acid showed the greatest contribution to the inhibitory activity of the ?-glucosidase enzyme (p<0.05). Conclusion: Our findings suggest that the phenolic compounds present in the varieties of quinoa and cañihua could modulate the inhibition of carbohydrate hydrolyzing enzymes associated with type 2 diabetes. © 2021 Phcogj.Com. This is an open-access article distributed under the terms of the Creative Commons Attribution 4.0 International license.Consejo Nacional de Ciencia, Tecnología e Innovación Tecnológica - Concyte
Lane-Emden equations perturbed by nonhomogeneous potential in the super critical case
No full textY. Ma is supported by Key R&D plan of Jiangxi Province, No:20181ACE50029, Y. Wang is supported by NNSF of China, No:12001252 and 12071189, by the Jiangxi Provincial Natural Science Foundation, No:20202ACBL201001 and 20202BAB201005, by the Science and Technology Research Project of Jiangxi Provincial Department of Education, No: 200325 and 200307, C. Torres was partially supported by CONCYTEC, Peru, 379-2019-FONDECYT “ASPECTOS CUALITATIVOS DE ECUACIONES NO-LOCALES Y APLICACIONES”Our purpose of this paper is to study positive solutions of Lane-Emden equation -?u=Vup in RN0 perturbed by a non-homogeneous potential V when p ? [pc,N+2N-2), where pc is the Joseph-Ludgren exponent. When p ? (NN-2,pc) the fast decaying solution could be approached by super and sub solutions, which are constructed by the stability of the k-fast decaying solution wk of -?u = up in RN \ 0 by authors in [9]. While the fast decaying solution wk is unstable for p ? (pc,N+2N-2) so these fast decaying solutions seem not able to disturbed like (0.1) by non-homogeneous potential V. A surprising observation that there exists a bounded sub solution of (0.1) from the extremal solution of -?u=uN+2N-2 in RN and then a sequence of fast decaying solutions and slow decaying solutions could be derived under appropriated restrictions for V. © 2021 Yong Ma et al., published by De Gruyter 2021.Consejo Nacional de Ciencia, Tecnología e Innovación Tecnológica - Concyte
Magnetic simulations of core–shell ferromagnetic bi-magnetic nanoparticles: The influence of antiferromagnetic interfacial exchange
No full textThis research was funded by Fondo Nacional de Desarrollo Cient?fico, Tecnol?gico y de Innovaci?n Tecnol?gica (FONDECYT-CONCYTEC), Project number 177-2020-FONDECYT.Magnetic properties of ferromagnetic nanostructures were studied by atomistic simulations following Monte Carlo and Landau–Lifshitz–Gilbert approaches. First, we investigated the influence of particle size and shape on the temperature dependence of magnetization for single cobalt and gadolinium nanoparticles and also in bi-magnetic Co@Gd core–shell nanoparticles with different sizes. The Landau–Lifshitz–Gilbert approach was subsequently applied for inspecting the magnetic hysteresis behavior of 2 and 4 nm Co@Gd core–shell nanoparticles with negative, positive, and zero values of interfacial magnetic exchange. We were able to demonstrate the influence of finite-size effect on the dependence of the Curie temperature of Co and Gd nanoparticles. In the Co@Gd core–shell framework, it was possible to handle the critical temperature of the hybrid system by adjusting the Co core size. In addition, we found an improvement in the coercive field values for a negative interfacial exchange energy and for a different core size, suggesting an exchange spring behavior, while positive and zero values of interfacial exchange constant showed no strong influence on the hysteresis behavior. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.Consejo Nacional de Ciencia, Tecnología e Innovación Tecnológica - Concyte
Metallomic profile in non-cirrhotic hepatocellular carcinoma supports a phenomenon of metal metabolism adaptation in tumor cells
No full textThis study was funded by the French National Alliance for Life Sciences and Health (ENV201408); LC was a recipient of a doctoral fellowship from French National Research Institute for Sustainable Development (IRD) (EMHE-ARTS-2016-878573B); JPC was a recipient of a doctoral fellowship from the Peruvian National Council for Science and Technology (212-2015-FONDECYT); SB has received funding from the European Union’s Horizon 2020 Framework program under the Marie Sk?odowska-Curie Actions 823935 and from the Alliance pour les Sciences de la Vie et de la Santé (AVIESAN), ITMO Cancer ENV201408, and LC, ER, and SCZ have received funding from the World Bank Group and FONDECYT-CONCYTEC 016-2018-FONDECYT/BM. The authors are grateful to Karina Cancino, Danny Cordova (INEN Cancer Research Biobank), Patricia Leroyer (NUMECAN), Alain Fautrel, Marine Seffals, Gevorg Ghukasyan (H2P2 platform). They also thank Dr Anne Corlu for the critical reviewing of the manuscript.We have previously described a form of hepatocellular carcinoma (HCC) in non-cirrhotic liver (HCC-NC) developed by Peruvian patients. We analyzed the metallomic profile in hepatic tissues from two independent cohorts exhibiting HCC-NC. Clinical, histopathological data, and HCC and non-tumoral liver (NTL) samples of 38 Peruvian and 38 French HCC-NC patients, were studied. Twelve metals were quantified using ICP/MS: Mn, Fe, Cu, Co, Zn, As, Se, Rb, Mo, Cd, Pb, and Sn. Associations between metals and survival were assessed. Our data showed significant differences between cohorts. Mean ages were 40.6 ± 20, 67.5 ± 9 years old for Peruvians and French, respectively. Fifty percent of the Peruvian patients were positive for the HBsAg, versus 3% in French patients. Mn, Cu, Zn, As, Se, Rb, Mo, Cd, Sn metal concentrations were higher in NTL of Peruvians. Importantly, metal concentrations were lower in HCC areas compared to NTL tissues in both cohorts, except for Cu for which mean concentration was higher in HCC (p < 0.05). Se concentration in HCC was associated with extended survival only in Peruvians. Our data, obtained in Peruvian and French HCC-NC cohorts, highlights similarity in the metallomic profile of HCC compared to NTL during the hepatic tumorigenesis in these specific groups of patients. © 2021, The Author(s).Consejo Nacional de Ciencia, Tecnología e Innovación Tecnológica - Concyte