Genome-Wide Association Study for Root Morphology and Phosphorus Acquisition Efficiency in Diverse Maize Panels.

Maximizing soil exploration through modifications of the root system is a strategy for plants to overcome phosphorus (P) deficiency. Genome-wide association with 561 tropical maize inbred lines from Embrapa and DTMA panels was undertaken for root morphology and P acquisition traits under low- and high-P concentrations, with 353,540 SNPs. P supply modified root morphology traits, biomass and P content in the global maize panel, but root length and root surface area changed differentially in Embrapa and DTMA panels. This suggests that different root plasticity mechanisms exist for maize adaptation to low-P conditions. A total of 87 SNPs were associated to phenotypic traits in both P conditions at -log10(p-value) ≥ 5, whereas only seven SNPs reached the Bonferroni significance. Among these SNPs, S9_137746077, which is located upstream of the gene GRMZM2G378852 that encodes a MAPKKK protein kinase, was significantly associated with total seedling dry weight, with the same allele increasing root length and root surface area under P deficiency. The C allele of S8_88600375, mapped within GRMZM2G044531 that encodes an AGC kinase, significantly enhanced root length under low P, positively affecting root surface area and seedling weight. The broad genetic diversity evaluated in this panel suggests that candidate genes and favorable alleles could be exploited to improve P efficiency in maize breeding programs of Africa and Latin America.

Microplastic Contamination and Ecological Status of Freshwater Ecosystems: A Case Study in Two Northern Portuguese Rivers.

BACKGROUND: Most European rivers have not yet achieved "good" ecological status. In addition, the presence and abundance of microplastics (MPs) in freshwater is a matter of great concern to the scientific community. METHODOLOGY: This study assesses the ecological status of four sampling sites of Selho (S1-S4) and Costa-Couros (C1-C4) rivers (Guimarães, Portugal), and the abundance of MPs in sediments and benthic macroinvertebrates (Oligochaeta) from those sites. RESULTS: All sites of both rivers under higher pressure did not reach a "good" ecological status (S2-S3, C2-C4) based on the macroinvertebrate community. High levels of nutrients were observed at all sites in both rivers (except C2), especially phosphorus. In the Oligochaeta's gut of Costa-Couros river, the high number of MPs seems to be associated with their weight (95.25 ± 25.61 to 1069.00 ± 385.30 MPs g/fresh weight), suggesting the existence of malnutrition and digestive disorders, whereas the highest number of MPs in gut (134.00 ± 30.36 to 558.6 ± 100.70 MPs g/fresh weight) were found for the heaviest organisms of Selho. CONCLUSIONS: Thus, sites with higher ecological status do not necessarily have lower abundance of MPs. In the sediments, urbanization seems to be the main driver for MP contamination. MP contamination is pervasive across the sediments and Oligochaeta's gut in both rivers. Since MPs have the potential to cause harm to environmental and human health, it is essential to monitor not only the ecological status of freshwaters, but also emerging pollutants such as MPs.

Improving accuracies of genomic predictions for drought tolerance in maize by joint modeling of additive and dominance effects in multi-environment trials.

Breeding for drought tolerance is a challenging task that requires costly, extensive, and precise phenotyping. Genomic selection (GS) can be used to maximize selection efficiency and the genetic gains in maize (Zea mays L.) breeding programs for drought tolerance. Here, we evaluated the accuracy of genomic selection (GS) using additive (A) and additive + dominance (AD) models to predict the performance of untested maize single-cross hybrids for drought tolerance in multi-environment trials. Phenotypic data of five drought tolerance traits were measured in 308 hybrids along eight trials under water-stressed (WS) and well-watered (WW) conditions over two years and two locations in Brazil. Hybrids' genotypes were inferred based on their parents' genotypes (inbred lines) using single-nucleotide polymorphism markers obtained via genotyping-by-sequencing. GS analyses were performed using genomic best linear unbiased prediction by fitting a factor analytic (FA) multiplicative mixed model. Two cross-validation (CV) schemes were tested: CV1 and CV2. The FA framework allowed for investigating the stability of additive and dominance effects across environments, as well as the additive-by-environment and the dominance-by-environment interactions, with interesting applications for parental and hybrid selection. Results showed differences in the predictive accuracy between A and AD models, using both CV1 and CV2, for the five traits in both water conditions. For grain yield (GY) under WS and using CV1, the AD model doubled the predictive accuracy in comparison to the A model. Through CV2, GS models benefit from borrowing information of correlated trials, resulting in an increase of 40% and 9% in the predictive accuracy of GY under WS for A and AD models, respectively. These results highlight the importance of multi-environment trial analyses using GS models that incorporate additive and dominance effects for genomic predictions of GY under drought in maize single-cross hybrids.

Use of counter-current chromatography as a selective extractor for the diterpenequinone 7α-hydroxyroyleanone from Tetradenia riparia.

A solvent system was developed for selective isolation by high-speed counter-current chromatography (HSCCC) of the benzoquinone 7α-hydroxyroileanone, 1, a bioactive diterpene from a dichloromethane extract of Tetradenia riparia leaves. Several solvent systems were initially studied, including hexane-ethyl acetate-methanol-water in several ratios, hexane-acetone-methanol-water, hexane-ethanol-water and hexane-acetonitrile-methanol, which gave recovery rates for the target compound between 13.4 and 35.9%. The new solvent system hexane-5% aqueous Na2CO3 (1:1) was developed based on the chemical ionization reaction of the benzoquinone hydroxyl group in the basic pH of the carbonate solution, prompted by the extraction procedure used for the extraction of lapachol (a natural naphtoquinone) from a Tabebuia species wood. By using the HSCCC chromatograph as a liquid-liquid extractor with the above mentioned solvent system the recovery rate of 1 increased to 81.8%, affording the quinone with 97% purity.

Anticoagulação na criança: desafios e perspectivas / Anticoagulation in children: challenges and perspectives

O tromboembolismo é uma condição que resulta em altas taxas de morbidade e mortalidade (BISS, 2016). Embora os eventos tromboembólicos sejam mias raros na população infantil, sua incidência em crianças esta em ascensão nas últimas décadas (YOUNG, 2011)...

Erratum: Congenital Chikungunya Virus Infection after an Outbreak in Salvador, Bahia, Brazil.

[This corrects the article DOI: 10.1055/s-0036-1587323.].

Congenital Chikungunya Virus Infection after an Outbreak in Salvador, Bahia, Brazil.

There is little information about the congenital chikungunya virus (CHIKV) transmission. We describe two cases of well-documented congenital CHIKV infection in Salvador-Brazil, where CHIKV has been identified since 2014. The outbreak in the city led to the clinical CHIKV diagnoses of both pregnant women 2 days before delivery. Urine and blood samples from the mothers and newborns were collected and tested for reverse transcription-polymerase chain reaction (PCR) analysis for Zika, dengue, and CHIKV. Both neonates and mothers had positive urine and serum PCR results for CHIKV. The newborns had significant perinatal complications and were admitted to the neonatal intensive care unit. The purpose of our case report is to show how severe congenital CHIKV infection can be and the importance to include CHIKV infection in the differential diagnosis of neonatal sepsis when mothers have clinical signs of the disease and live in an affected area.

Transthyretin participates in beta-amyloid transport from the brain to the liver--involvement of the low-density lipoprotein receptor-related protein 1?

Transthyretin (TTR) binds Aß peptide, preventing its deposition and toxicity. TTR is decreased in Alzheimer's disease (AD) patients. Additionally, AD transgenic mice with only one copy of the TTR gene show increased brain and plasma Aß levels when compared to AD mice with both copies of the gene, suggesting TTR involvement in brain Aß efflux and/or peripheral clearance. Here we showed that TTR promotes Aß internalization and efflux in a human cerebral microvascular endothelial cell line, hCMEC/D3. TTR also stimulated brain-to-blood but not blood-to-brain Aß permeability in hCMEC/D3, suggesting that TTR interacts directly with Aß at the blood-brain-barrier. We also observed that TTR crosses the monolayer of cells only in the brain-to-blood direction, as confirmed by in vivo studies, suggesting that TTR can transport Aß from, but not into the brain. Furthermore, TTR increased Aß internalization by SAHep cells and by primary hepatocytes from TTR+/+ mice when compared to TTR-/- animals. We propose that TTR-mediated Aß clearance is through LRP1, as lower receptor expression was found in brains and livers of TTR-/- mice and in cells incubated without TTR. Our results suggest that TTR acts as a carrier of Aß at the blood-brain-barrier and liver, using LRP1.

The genome of Anopheles darlingi, the main neotropical malaria vector.

Anopheles darlingi is the principal neotropical malaria vector, responsible for more than a million cases of malaria per year on the American continent. Anopheles darlingi diverged from the African and Asian malaria vectors ∼100 million years ago (mya) and successfully adapted to the New World environment. Here we present an annotated reference A. darlingi genome, sequenced from a wild population of males and females collected in the Brazilian Amazon. A total of 10 481 predicted protein-coding genes were annotated, 72% of which have their closest counterpart in Anopheles gambiae and 21% have highest similarity with other mosquito species. In spite of a long period of divergent evolution, conserved gene synteny was observed between A. darlingi and A. gambiae. More than 10 million single nucleotide polymorphisms and short indels with potential use as genetic markers were identified. Transposable elements correspond to 2.3% of the A. darlingi genome. Genes associated with hematophagy, immunity and insecticide resistance, directly involved in vector-human and vector-parasite interactions, were identified and discussed. This study represents the first effort to sequence the genome of a neotropical malaria vector, and opens a new window through which we can contemplate the evolutionary history of anopheline mosquitoes. It also provides valuable information that may lead to novel strategies to reduce malaria transmission on the South American continent. The A. darlingi genome is accessible at www.labinfo.lncc.br/index.php/anopheles-darlingi.