Environmental conditions and plant physiology modulate Cu phytotoxicity in field-contaminated soils.

Foliar Cu concentration has been widely used as a biomarker of plant growth in phytotoxicity bioassays. This relation has helped find plant processes altered by Cu in dose-response experiments (a bivariate approach). However, when plants are grown in field conditions, their responses can vary in function of multiple variables, such as the environment, plant physiology, and other elements in plant (plant ionome). These sources of variability are commonly unreported, which could limit bioassays' utility. Thus, the present study aimed to assess and integrate the mentioned sources of variability on Cu phytotoxicity. Lettuce was used as plant model. Lettuces were grown in growth chambers with contrasting light and air humidity conditions and on two different field-contaminated soils (sandy and loamy soils). Results showed that environmental conditions significantly affected foliar Cu and plant growth, but this effect differed in the two studied soils. Foliar Cu was not a good biomarker of plant growth. In contrast, integrating the potential phytotoxicity effect with the plant's nutritional status allowed a better understanding of plant growth. We remarked on using a structural equation modeling approach (SEM) to integrate plant physiology and plant ionome as moderators of plant growth. Results showed that plant growth was primarily related to plant nutritional status rather than Cu phytotoxicity. Also, the foliar Cu concentration would affect plant nutritional status due to photosynthesis-related plant processes and cation balance. Finally, this research invites to state and include sources of variability when assessing phytotoxicity. This way, it is possible to advance toward understanding complex linked processes occurring in field conditions.

The first observation of copulation in Andean catfish Astroblepus ubidiai (Siluriformes, Astroblepidae), in Lago San Pablo, Imbabura, Ecuador.

The reproductive behaviour of the Andean catfish Astroblepus ubidiai was observed directly and with an underwater camera in a spring located next to Lago San Pablo in the province of Imbabura, Ecuador, in late 2015 and early 2016. Five mating attempts were observed, four of which were video-taped, and two of which resulted in complete copulation. During copulation, the male grabs the female from the top of the head with its buccal disc and pelvic fins and, from this position, bends its body forming a "C" to reach the genital pore of the female and introduce its copulatory organ. Once copulation is complete, the female swims away rapidly. Details of the copulation are described here through illustrations.

Chilean regulations on metal-polluted soils: The need to advance from adapting foreign laws towards developing sovereign legislation.

Chile as a major international Cu producer faces serious soil contamination issues in mining areas. Currently Chile does not have any specific law governing the maximum permissible concentrations of metals in soils to protect ecosystems and human health. Chile heavily relies on the use of environmental laws of 14 foreign countries; the choice of the country depends on the similarity of its environmental conditions with those in Chile. In this study, we used an online database to compare the similarity of Chilean rocks to those in foreign countries. Likewise, we performed soil sampling and determined the background concentrations of Cu, As, Pb, and Zn in soils of the Aconcagua basin, the largest river basin in the Valparaiso Region of central Chile. The results showed that geochemical patterns in Chile have the greatest resemblance to New Zealand, Mexico, and Italy. The background Cu concentration in the Aconcagua basin (134 mg kg-1) exceeded the legislated limits of New Zealand (100 mg kg-1) and Italy (120 mg kg-1), whereas the background Zn concentration (200 mg kg-1) exceeded the legislated limit of Italy (150 mg kg-1). Due to the elevated natural abundance of Cu and Zn in Chile, international laws should not be applied in Chile for the assessment of soil contamination. In addition, we assessed ecological risk using the results of our previous studies obtained by analyzing native field-contaminated soils of the Valparaiso region. In the Aconcagua basin, Cu posed high risk for plants in 11% of the samples, whereas As posed high risk for earthworms in 48% of the samples. We suggest that future studies are required to search for other organisms that can serve as biomarkers of metal toxicity because our previous studies were limited to plants and earthworms. Importantly, As posed high risk to human health in 25% of the samples in our study. There is a need for future studies to demonstrate empirically an association between soil As and children's blood As in order to establish the national threshold values of soil As to protect human health. We conclude that there is an urgent need in Chile to advance from the current approach of adapting foreign laws to developing Chilean sovereign environmental legislation.

Identification of Coli Surface Antigen 23, a novel adhesin of enterotoxigenic Escherichia coli.

Enterotoxigenic Escherichia coli (ETEC) is an important cause of diarrhea, mainly in developing countries. Although there are 25 different ETEC adhesins described in strains affecting humans, between 15% and 50% of the clinical isolates from different geographical regions are negative for these adhesins, suggesting that additional unidentified adhesion determinants might be present. Here, we report the discovery of Coli Surface Antigen 23 (CS23), a novel adhesin expressed by an ETEC serogroup O4 strain (ETEC 1766a), which was negative for the previously known ETEC adhesins, albeit it has the ability to adhere to Caco-2 cells. CS23 is encoded by an 8.8-kb locus which contains 9 open reading frames (ORFs), 7 of them sharing significant identity with genes required for assembly of K88-related fimbriae. This gene locus, named aal (adhesion-associated locus), is required for the adhesion ability of ETEC 1766a and was able to confer this adhesive phenotype to a nonadherent E. coli HB101 strain. The CS23 major structural subunit, AalE, shares limited identity with known pilin proteins, and it is more closely related to the CS13 pilin protein CshE, carried by human ETEC strains. Our data indicate that CS23 is a new member of the diverse adhesin repertoire used by ETEC strains.

Financial Distress and Psychological Well-Being During the COVID-19 Pandemic.

Objective: We examine the impact of financial distress caused by the COVID-19 pandemic on mental health and psychological well-being. Methods: We analyze cross-sectional survey data (n = 2,545) from the Life during Pandemic study in Chile. We estimate linear probability models to analyze the relationship between economic fragility, financial distress, and psychological well-being. Results: Our findings show unemployment and income loss are highly predictive of experiencing a range of financial problems, such as a lack of savings, as well as difficulties paying bills, consumer debt, and mortgage loans. In turn, financial distress leads to a higher prevalence of poor well-being and mental health deterioration, and sleep problems. Conclusion: Expansion of mental health assistance services are needed, as new diagnosis of mental health conditions has increased, but treatment has not, pointing to a barrier in the access to some mental health care services during the pandemic. Policies designed with the objective of improving financial education are necessary to increase precautionary savings and financial resilience, and alleviate the psychological burden of debt in the future.

Characterization of genomic island 3 and genetic variability of Chilean field strains of Brucella abortus.

One of the capabilities developed by bacteria is the ability to gain large fragments of DNA from other bacteria or to lose portions of their own genomes. Among these exchangeable fragments are the genomic islands (GIs). Nine GIs have been identified in Brucella, and genomic island 3 (GI-3) is shared by two pathogenic species, B. melitensis and B. abortus. GI-3 encodes mostly unknown proteins. One of the aims of this study was to perform pulsed-field gel electrophoresis (PFGE) on field isolates of B. abortus from Chile to determine whether these isolates are clonally related. Furthermore, we focused on the characterization of GI-3, studying its organization and the genetic conservation of the GI-3 sequence using techniques such as tiling-path PCR (TP-PCR) and restriction fragment length polymorphism-PCR (RFLP-PCR). Our results, after PFGE was performed on 69 field isolates of B. abortus from Chile, showed that the strains were genetically homogeneous. To increase the power of genetic discrimination among these strains, we used multiple locus variable-number tandem-repeat (VNTR) analysis with 16 loci (MLVA-16). The results obtained by MLVA-16 showed that the strains of B. abortus were genetically heterogeneous and that most of them clustered according to their geographic origin. Of the genetic loci studied, panel 2B was the one describing the highest diversity in the analysis, as well as locus Bruce19 in panel 2A. In relation to the study of GI-3, our experimental analysis by TP-PCR identified and confirmed that GI-3 is present in all wild strains of B. abortus, demonstrating the high stability of gene cluster GI-3 in Chilean field strains.

Distribution of classical and nonclassical virulence genes in enterotoxigenic Escherichia coli isolates from Chilean children and tRNA gene screening for putative insertion sites for genomic islands.

Enterotoxigenic Escherichia coli (ETEC) is an important cause of diarrhea. Three adhesins (Tia, TibA, EtpA), an iron acquisition system (Irp1, Irp2, and FyuA), a GTPase (LeoA), and an autotransporter (EatA) are ETEC virulence-related proteins that, in contrast to the classical virulence factors (enterotoxins and fimbrial colonization factors) have not heretofore been targets in characterizing isolates from epidemiological studies. Here, we determined the occurrence of these nonclassical virulence genes in 103 ETEC isolates from Chilean children with diarrhea and described their association with O serogroups and classical virulence determinants. Because tia, leoA, irp2, and fyuA are harbored by pathogenicity islands inserted into the selC and asnT tRNA genes (tDNAs), we analyzed the regions flanking these loci. Ten additional tDNAs were also screened to identify hot spots for genetic insertions. Associations between the most frequent serogroups and classical colonization factor (CF)-toxin profiles included O6/LT-STh/CS1-CS3-CS21 (i.e., O6 serogroup, heat-labile [LT] and human heat-stable [STh] enterotoxins, and CFs CS1, -3 and -21), O6/LT-STh/CS2-CS3-CS21, and O104-O127/STh/CFAI-CS21. The eatA and etpA genes were detected in more than 70% of the collection, including diverse serogroups and virulence profiles. Sixteen percent of the ETEC strains were negative for classical and nonclassical adhesins, suggesting the presence of unknown determinants of adhesion. The leuX, thrW, and asnT tDNAs were disrupted in more than 65% of strains, suggesting they are hot spots for the insertion of mobile elements. Sequences similar to integrase genes were identified next to the thrW, asnT, pheV, and selC tDNAs. We propose that the eatA and etpA genes should be included in characterizations of ETEC isolates in future epidemiological studies to determine their prevalence in other geographical regions. Sequencing of tDNA-associated genetic insertions might identify new ETEC virulence determinants.

Gender Inequality and Mental Health During the COVID-19 Pandemic.

Objective: We explore gender differences in mental health deterioration and psychological well-being due to the COVID-19 pandemic, as well as the mechanisms through which these differences may operate. Methods: Using data from the Life during Pandemic survey in Chile, which covers 2,545 adult respondents, we estimate econometric models to explore gender differences in psychological well-being and mental health as well as economic fragility and household workload during the COVID-19 pandemic. Results: We find women are more likely to report overall bad mental health and deterioration of well-being. They are also more likely to have a new diagnosis of a mental health problem, to be pursuing treatment and taking prescription medication. Moreover, women report an increase in household chores and in childcare, and are more likely to have lost their employment or experienced a loss of income due to the pandemic. Conclusion: Our results offer a general picture of gender differences in the psychological impact of COVID-19. We argue that policies that mitigate economic stress and address the needs of women specifically may ease mental health deterioration due to the pandemic.

Does Education Mitigate the Effect of Population Aging on Health Expenditure? A Panel Data Study of Latin American Countries.

Objective: To examine whether the effect of population aging on healthcare expenditures as a share of Gross Domestic Product (GDP) is attenuated in more educated countries. Method: The analysis is based on a dataset of 22 Latin American countries between 1995 and 2013. We estimate panel data models with country and time fixed effects, and control for potential nonlinear effects of population aging on health expenditure. Results: We find population aging increases health expenditure as a share of GDP in economies characterized by low levels of education, but this effect is mitigated in economies with higher levels of education. Results are driven by private health expenditures. Discussion: Results suggest population aging and education have a stronger influence on healthcare expenditures in less developed countries. This finding is important in a context in which the rapid growth of the aging population is likely to lead to significant costs in terms of health expenditures, but less so in more educated societies.

Genes related to long polar fimbriae of pathogenic Escherichia coli strains as reliable markers to identify virulent isolates.

Lpf (stands for long polar fimbriae) is one of the few adhesive factors of enterohemorrhagic Escherichia coli O157:H7 associated with colonization of the intestine. E. coli O157:H7 strains possess two lpf loci encoding highly regulated fimbrial structures. Database analysis of the genes encoding the major fimbrial subunits demonstrated that they are present in commensal as well as pathogenic (both intestinal and extraintestinal) E. coli strains and in Salmonella strains and that the lpfA1 and lpfA2 genes are highly prevalent among LEE (locus of enterocyte effacement)-positive E. coli strains associated with severe and/or epidemic disease. Further DNA sequence analysis of the lpfA1 and lpfA2 genes from different attaching-and-effacing E. coli strains has led us to the identification of several polymorphisms and the classification of the major fimbrial subunits into distinct variants. Using collections of pathogenic E. coli isolates from Europe and Latin America, we demonstrated that the different lpfA types are associated with the presence of specific intimin (eae) adhesin variants and, most importantly, that they are found in specific E. coli pathotypes. Our results showed that the use of these fimbrial genes as markers, in combination with the different intimin types, resulted in a specific test for the identification of E. coli O157:H7, distinguishing it from other pathogenic E. coli strains.

On Adaptive Boosting for System Identification.

In the field of machine learning, the algorithm Adaptive Boosting has been successfully applied to a wide range of regression and classification problems. However, to the best of the authors' knowledge, the use of this algorithm to estimate dynamical systems has not been exploited. In this brief, we explore the connection between Adaptive Boosting and system identification, and give examples of an identification method that makes use of this connection. We prove that the resulting estimate converges to the true underlying system for an output-error model structure under reasonable assumptions in the large sample limit and derive a bound of the model mismatch for the noise-free case.

Aves de la cordillera del Kutukú, Morona Santiago, sureste de Ecuador / Birds of the Cordillera del Kutukú, Morona Santiago, Southeastern Ecuador

Resumen La cordillera del Kutukú está ubicada al sureste de Ecuador y se encuentra parcialmente aislada de la cordillera de los Andes. Realizamos cinco expediciones a este macizo, donde obtuvimos de manera directa información referente a la riqueza de aves. Además, con el fin de generar un listado más completo, realizamos una recopilación de registros publicados y revisamos colecciones de museos ecuatorianos. En total registramos 501 especies de aves, en un rango entre 500 - 2300 m de altitud. Encontramos trece especies con nuevas ampliaciones de distribución altitudinal y/o latitudinal. Veintiséis especies de aves (5.2%) están en alguna categoría de amenaza a su conservación, a nivel mundial y nacional. Las escasas vías de acceso, sumadas a las políticas de ingreso al territorio, por parte de la etnia Shuar, han favorecido la preservación de los bosques, especialmente aquellos por encima de los 1800 m. Es así que, el conocimiento biológico de esta área queda aún por descubrir. Esta zona remota protege una importante diversidad, así como poblaciones de aves amenazadas, recursos hídricos, además del territorio y cultura de las comunidades que la habitan. Desafortunadamente la totalidad de la cordillera se encuentra concesionada para exploraciones de proyectos mineros. Por tanto, se requiere la atención de las autoridades regionales y nacionales para aunar esfuerzos que aseguren su conservación y exploración biológica.

Abstract The cordillera del Kutukú is located in the southeastern Ecuador and is partially isolated from the Andes mountain range. We conducted five field expeditions to the region, where we directly obtained information regarding the richness of birds. In addition, we compile bird richness data from published records and Ecuadorian museum's collections in order to provide an updated list. A total of 501 bird species were registered, in an elevation range from 500 to 2.300 m a.s.l. We found 13 species with new latitudinal and/or longitudinal distribution extensions. Twenty-six species (5.2%) are in an elevated risk category nationally or globally. The region's limited roads, added to the Shuar ethnic group policies for entering to their territory has aided in the conservation of forests, especially those over 1800 m a.s.l. Thus, the biological knowledge of this area remains to be discovered. This remote area protects an important diversity, as well as threatened bird populations, water resources, territory and culture of the indigenous groups that inhabit it. However, unfortunately the entire mountain range is under concession for exploration of mining projects. Therefore, the attention of regional and national authorities is required to join efforts to ensure their conservation and biological exploration.

A tRNA(Glu) that uncouples protein and tetrapyrrole biosynthesis.

Glu-tRNA is either bound to elongation factor Tu to enter protein synthesis or is reduced by glutamyl-tRNA reductase (GluTR) in the first step of tetrapyrrole biosynthesis in most bacteria, archaea and in chloroplasts. Acidithiobacillus ferrooxidans, a bacterium that synthesizes a vast amount of heme, contains three genes encoding tRNA(Glu). All tRNA(Glu) species are substrates in vitro of GluRS1 from A. ferrooxidans.Glu-tRNA(3)(Glu), that fulfills the requirements for protein synthesis, is not substrate of GluTR. Therefore, aminoacylation of tRNA(3)(Glu) might contribute to ensure protein synthesis upon high heme demand by an uncoupling of protein and heme biosynthesis.

Characterization of the most prevalent colonization factor antigens present in Chilean clinical enterotoxigenic Escherichia coli strains using a new multiplex polymerase chain reaction.

Current methods to detect the colonization factor antigens (CFAs) associated with enterotoxigenic Escherichia coli (ETEC) strains are cumbersome, with some methods requiring antibodies that are not readily available. To achieve a gene-based method, we designed 2 multiplex polymerase chain reaction reactions to detect genes encoding the most common ETEC fimbrial colonization factors, including CFA/I and coli surface (CS) antigens CS1, CS2, CS3, CS4, CS5, and CS6. Analysis of 183 clinical ETEC strains shows that the most prevalent colonization factors were CFA/I only, CS1 and CS3, CS2 and CS3, and CS6 only. Interestingly, we identified 3 clinical isolates expressing CS1 only without its regulator rns. The method described here proved to be rapid and robust and correlates well with phenotypic expression of the CFAs, becoming a novel molecular diagnostic and research tool for future epidemiologic studies.