Neolignans from Licaria rigida

Trunk wood of Licaria rigida contains the neolignans eusiderin, eusiderin-B, canellin-A and canellin-C.     

The recombination landscape and multiple QTL mapping in a Solanum tuberosum cv. ‘Atlantic’-derived F1 population

There are many challenges involved with the genetic analyses of autopolyploid species, such as the tetraploid potato, Solanum tuberosum (2n = 4x = 48). The development of new analytical methods has made it valuable to re-analyze an F₁ population (n = 156) derived from a cross involving ‘Atlantic’, a widely grown chipping variety in the USA. A fully integrated genetic map with 4285 single nucleotide polymorphisms, spanning 1630 cM, was constructed with MAPpoly software. We observed that bivalent configurations were the most abundant ones (51.0~72.4% depending on parent and linkage group), though multivalent configurations were also observed (2.2~39.2%). Seven traits were evaluated over four years (2006–8 and 2014) and quantitative trait loci (QTL) mapping was carried out using QTLpoly software. Based on a multiple-QTL model approach, we detected 21 QTL for 15 out of 27 trait-year combination phenotypes. A hotspot on linkage group 5 was identified with co-located QTL for maturity, plant yield, specific gravity, and internal heat necrosis resistance evaluated over different years. Additional QTL for specific gravity and dry matter were detected with maturity-corrected phenotypes. Among the genes around QTL peaks, we found those on chromosome 5 that have been previously implicated in maturity (StCDF1) and tuber formation (POTH1). These analyses have the potential to provide insights into the biology and breeding of tetraploid potato and other autopolyploid species.Subject terms: Polyploidy in plants, Genetic linkage study, Quantitative trait, Plant breeding     

An apparent lack of prezygotic reproductive isolation among 42 sympatric species of Bromeliaceae in southeastern Brazil

The Atlantic rainforest in southeastern Brazil is one the main centers of diversification of Bromeliaceae. Empirical estimates of the relative importance of different pre- and postzygotic barriers to gene flow between recently diverged species are important for understanding speciation processes. While many bromeliad species easily hybridize in cultivation, few records of natural hybrids between closely related sympatric species suggest the existence of strong prezygotic barriers. A community of 42 sympatric bromeliad species, represented by nine genera (Aechmea, Billbergia, Edmundoa, Neoregelia, Nidularium, Quesnelia, Racinaea, Tillandsia, and Vriesea), were surveyed from 2004–2005 to assess the role of microhabitat isolation, phenological isolation and ethological isolation as potential prezygotic barriers. These bromeliads are abundant in the understory and frequently grow densely aggregated in multispecific patches that may facilitate promiscuous pollination. There was a large overlap of flowering periods even between congeneric species. Most species shared a similar assemblage of flower visitors; the hummingbird Rhamphodon naevius was the major visitor for 35 species. Only one putative hybrid was observed. This uncommonness of hybridization is puzzling, given that the prezygotic isolation mechanisms investigated are potentially weak to effectively avoid interspecific pollination.     

Hypoxia-Inducible Factor-1α (HIF-1α) Inhibition Impairs Retinoic Acid-Induced Differentiation in SH-SY5Y Neuroblastoma Cells,Leading to Reduced Neurite Length and Diminished Gene Expression Related to Cell Differentiation

Neuroblastoma is the most common extracranial solid tumour in childhood, originated from cells of the neural crest during the development of the Sympathetic Nervous System. Retinoids are vitamin-A derived differentiating agents utilised to avoid disease resurgence in high-risk neuroblastoma treatment. Several studies indicate that hypoxia—a common feature of the tumoural environment—is a key player in cell differentiation and proliferation. Hypoxia leads to the accumulation of the hypoxia-inducible factor-1α (HIF-1α). This work aims to investigate the effects of the selective inhibition of HIF-1α on the differentiation induced by retinoic acid in human neuroblastoma cells from the SH-SY5Y lineage to clarify its role in cell differentiation. Our results indicate that HIF-1α inhibition impairs RA-induced differentiation by reducing neuron-like phenotype and diminished immunolabeling and expression of differentiation markers.

Graphic Abstract

HIF1A is involved in Retinoic Acid (RA) induced differentiation in SH-SY5Y neuroblastoma cells. siRNA HIF1A gene silencing leads to a weaker response to RA, demonstrated by changes in the neuro-like phenotype and diminished expression of differentiation markers.

     

Variable levels of introgression between the endangered Podarcis carbonelli and highly divergent congeneric species

Recent empirical studies have demonstrated that speciation with gene flow is more common than previously thought. From a conservation perspective, the potential negative effects of hybridization raise concerns on the genetic integrity of endangered species. However, introgressive hybridization has also been growingly recognized as a source of diversity and new advantageous alleles. Carbonell’s wall lizard (Podarcis carbonelli) is an endangered species whose distribution overlaps with four other congeneric species. Our goal here was to determine whether P. carbonelli is completely reproductively isolated from its congeners and to evaluate the relevance of hybridization and interspecific gene flow for developing a conservation plan. We used restriction site associated DNA (RAD) sequencing to discover SNPs in samples from four contact zones between P. carbonelli and four other species. Principal component analysis, multilocus genotype assignment and interspecific heterozygosity suggest incomplete reproductive isolation and ongoing gene flow between species. However, hybridization dynamics vary across all pairs, suggesting complex interactions between multiple intrinsic and extrinsic barriers. Despite seemingly ubiquitous interspecific gene flow, we found evidence of strong reproductive isolation across most contact zones. Instead, indirect effects of hybridization like waste of reproductive effort in small isolated populations may be more problematic. Our results highlight the need to further evaluate the consequences of introgression for P. carbonelli, both on a geographic and genomic level and included in a comprehensive and urgently needed conservation plan. Besides, those findings will add important insights on the potential effects of hybridization and introgression for endangered species.Subject terms: Population genetics, Speciation     

Testing for functional significance of traits: Effect of the light environment in tropical tree saplings

1. Functional traits have been examined to explain the growth rates of forest communities in different sites. However, weak or nonexistent relations are often found, especially due to the following methodological aspects: 1) lack of an environmental context (e.g., light, water, or nutrient supply), 2) use of nonfunctional traits, 3) an approach that does not contemplate phenotypic integration, and 4) neglect of intraspecific variation.
2. Here we measured relative growth rates, crown, and leaf traits in saplings of six tropical tree species growing in two light environments (Gap and Understory) to test whether contrasting light environments modulates trait–trait and trait–growth relationships. Moreover, we tested whether models that integrate traits of different dimensions of the plant (crown and leaf) improve the strength of trait–growth relations.
3. Light availability changed both trait–trait and trait–growth relationships. Overall, in Understory, crown traits (crown length and total leaf area) have a stronger effect on growth rates, while physiological traits related to nutrient acquisition (nitrogen concentration), photochemical efficiency (chlorophyll pigments and chlorophyll a fluorescence), and biochemical efficiency (potassium use efficiency) are strong in Gap. Models including multiple traits explained growth rates better in Gap (up to 62%) and Understory (up to 47%), but just in Gap the best model comprises traits that are representative of different dimensions of the plant.
4. Synthesis. We advanced the knowledge behind the light effects on tree sapling by posit that trait–trait and trait–growth relationships vary across light environments. Therefore, light availability is a key environmental factor to be considered when choosing the set of traits to be measured in functional approach studies using tropical tree saplings. In compliance with the phenotype integration hypothesis, functional traits are better predictors of growth rates when grouped in a set of traits of different dimensions of the plant that represent different functional mechanisms.

     

A Novel Phosphorylated Lipid Counteracts Activation of the Renal Plasma Membrane (Ca2+ + Mg2+)ATPase by Endogenous Phosphatidylinositol-4-Phosphate

The plasma membrane (Ca²⁺ + Mg²⁺)ATPase is activated by acidic phospholipids in reconstituted systems. In this report it is shown that reversible phosphorylation of endogenous phosphatidylinositol regulates the renal plasma membrane (Ca²⁺ + Mg²⁺)ATPase, and that a novel phosphorylated lipid that can be isolated from the same membrane strongly counteracts the stimulatory effect of phosphatidylinositol-4-phosphate.     

Description of the external morphology of the puparia of eight species of bat flies (Diptera: Streblidae)

ABSTRACT

The Dipteran family Streblidae are ectoparasites of bats. These flies are viviparous and have an intrauterine larval life phase, a free-living sessile puparium phase and the adult obligate parasite. Here we describe the external morphology of the puparium of Aspidoptera phyllostomatis (Perty, 1833), Megistopoda aranea (Coquillett, 1899), M. proxima (Séguy, 1826), Noctiliostrebla morena Alcantara et al., 2019, Paradyschiria parvula Falcoz, 1931, Strebla consocia Wenzel, 1966, Trichobius joblingi Wenzel, 1966 and T. longipes (Rudow, 1871) and provide an identification key. We also describe the method we developed for collecting the puparia, which was done between April 2015 and August 2016. The characters that most differentiated the species were spiracles and ornaments.     

Space use by giant anteaters (Myrmecophaga tridactyla) in a protected area within human‐modified landscape

1. Spatial ecology data are essential for conservation purposes, especially when extinction risk is influenced by anthropogenic actions. Space use can reveal how individuals use the habitat, how they organize in space, and which components are key resources for the species.
2. We evaluated the space use and multiscale habitat selection of giant anteaters (Myrmecophaga tridactyla), a vulnerable Neotropical mammal, in a Cerrado site within a human‐modified landscape in southeastern Brazil.
3. We used GPS transmitters to track eight anteaters in the wild. With the resulting dataset, we estimated home range and core‐area sizes and then used two overlap indexes. We assessed habitat selection by compositional analysis and analyzed events of spatio‐temporal proximity.
4. The average Brownian bridge kernel estimate of home range size was 3.41 km² (0.92–7.9). Regarding home range establishment, five individuals showed resident behavior. Males (n = 4) had larger home ranges and were more active than females (n = 4). Despite the spatial overlap of home range (above 40% in four dyads), maximum temporal space sharing was 18%. Giant anteaters were found in proximity. Habitat selection favored savanna, and exotic timber plantation was always avoided. Roads and built‐up areas were selected secondarily at the landscape level.
5. The selection of anthropogenic sites denotes behavioral plasticity regarding modified habitats. However, the high selectivity for savanna, at all levels, demonstrates a high dependence on natural habitats, which provide the necessary resources for the species. The recurrent proximity of male–to‐female anteaters may indicate reproductive behavior, which is essential for maintaining this isolated population.