Changes in the feeding ecology of South American sea lions on the southern Brazilian coast over the last two decades of excessive fishing exploration

In the last decades, an increasing fishing effort and a decreasing trend in fish catches have been observed in southern Brazil. Considering that marine mammals and fisheries usually compete for the same resources, it is reasonable to presume that the feeding ecology of these predators is affected by the current scenario. To evaluate this hypothesis, long-term variation in the diet of the South American sea lion (Otaria flavescens) relative to fisheries exploitation was analyzed for two periods (1993–2003 versus 2004–2014). The degree of overlap between the relative biomass of the sea lions’ diet and the target species of six types of local fishery was analyzed. An increase in prey overlap between sea lions and fisheries was observed in the more recent sampling period, along with an increase in prey diversity, richness, and niche breadth of the sea lions’ diet. These results suggest that the overfishing scenario could partly explain the modified feeding ecology of the sea lions. In this context, we recommend a review and better regulation of the current fishing effort in the region, which we believe will be an important step to maintain the fish stocks and minimize the impact of fishing on marine top predators.     

Effect of flood pulses on the trophic ecology of four piscivorous fishes from the eastern Amazon

This study investigated the effect of hydrological periods on the feeding activity and trophic interactions of four piscivorous fishes from the middle Xingu River, Brazil: pike‐characid Boulengerella cuvieri, dogtooth characin Hydrolycus armatus, dogtooth characin Hydrolycus tatauaia and South American silver croaker Plagioscion squamosissimus. Repletion Index (I_R%), Alimentary Index (I_Ai%) and food web properties were calculated for each species. A total of 825 specimens were collected. The I_R showed changes in feeding intensity of B. cuvieri, H. armatus and H. tatauaia among hydrological periods. Flood pulse showed no influence on composition and importance of food items consumed. Trophic connections showed that connectivity ranged from 0.025 to 0.038. The highest number of trophic connections (75) occurred in the high‐water period, when 51 food items were recorded and the lowest number of trophic connections (43) occurred in receding water, with 31 food items. In all food webs, over 45% of food items were consumed by only one species (ultra‐peripheral items), which is common in piscivorous fishes.     

Effects of outdoor cultures on the growth and lipid production of <Emphasis Type="Italic">Phaeodactylum tricornutum</Emphasis> using closed photobioreactors

One of the principal challenges for large scale production of microalgae is the high costs of biomass production. Aiming for minimize this problem, microalgal biodiesel production should focus on outdoors cultures, using available solar light and allowing lower energy cost process. Testing species that proved to be common and easy to culture may be a good approach in this process. The present work reports indoor-outdoor cultures of Phaeodactylum tricornutum using different bioreactors types, using cell growth, biochemical composition, and the profiles of the fatty acids produced as the parameters to test the optimization processes. The results show that the use of outdoor cultures is a good choice to obtain P. tricornutum biomass with a good potential for biodiesel production. The microalgae produced reached better growth efficiency, major lipid content and showed an increment in the percentage of saturated fatty acids (required on the biodiesel production) respect indoor cultures. These results are important to show the relevance of using outdoor cultures as a way to improve the efficiency and the energetic balance of the biodiesel production with P. tricornutum algae.     

<Emphasis Type="Italic">chr</Emphasis> genes from adaptive replicons are responsible for chromate resistance by <Emphasis Type="Italic">Burkholderia xenovorans</Emphasis> LB400

The chromate ion transporter (CHR) superfamily includes proteins that confer chromate resistance by extruding toxic chromate ions from cytoplasm. Burkholderia xenovorans strain LB400 encodes six CHR homologues in its multireplicon genome and has been reported as highly chromate-resistant. The objective of this work was to analyze the involvement of chr redundant genes in chromate resistance by LB400. It was found that B. xenovorans plant rhizosphere strains lacking the megaplasmid are chromate-sensitive, suggesting that the chr gene present in this replicon is responsible for the chromate-resistance phenotype of the LB400 strain. Transformation of a chromate-sensitive B. xenovorans strain with each of the six cloned LB400 chr genes showed that genes from ‘adaptive replicons’ (chrA1b and chr1NCb from chromosome 2 and chrA2 from the megaplasmid) conferred higher chromate resistance levels than chr genes from ‘central’ chromosome 1 (chrA1a, chrA6, and chr1NCa). An LB400 insertion mutant affected in the chrA2 gene displayed a chromate-sensitive phenotype, which was fully reverted by transferring the chrA2 wild-type gene, and partially reverted by chrA1b or chr1NCb genes. These data indicate that chr genes from adaptive replicons, mainly chrA2 from the megaplasmid, are responsible for the B. xenovorans LB400 chromate-resistance phenotype.     

Global genetic diversity of Aedes aegypti

Mosquitoes, especially Aedes aegypti, are becoming important models for studying invasion biology. We characterized genetic variation at 12 microsatellite loci in 79 populations of Ae. aegypti from 30 countries in six continents, and used them to infer historical and modern patterns of invasion. Our results support the two subspecies Ae. aegypti formosus and Ae. aegypti aegypti as genetically distinct units. Ae. aegypti aegypti populations outside Africa are derived from ancestral African populations and are monophyletic. The two subspecies co‐occur in both East Africa (Kenya) and West Africa (Senegal). In rural/forest settings (Rabai District of Kenya), the two subspecies remain genetically distinct, whereas in urban settings, they introgress freely. Populations outside Africa are highly genetically structured likely due to a combination of recent founder effects, discrete discontinuous habitats and low migration rates. Ancestral populations in sub‐Saharan Africa are less genetically structured, as are the populations in Asia. Introduction of Ae. aegypti to the New World coinciding with trans‐Atlantic shipping in the 16th to 18th centuries was followed by its introduction to Asia in the late 19th century from the New World or from now extinct populations in the Mediterranean Basin. Aedes mascarensis is a genetically distinct sister species to Ae. aegypti s.l. This study provides a reference database of genetic diversity that can be used to determine the likely origin of new introductions that occur regularly for this invasive species. The genetic uniqueness of many populations and regions has important implications for attempts to control Ae. aegypti, especially for the methods using genetic modification of populations.     

Diversity of macrofungi and exploitation of edible mushroom resources in the National Park “Appennino Lucano,Val D'Agri,Lagonegrese” (Italy)

An investigation on the macrofungal diversity of the National Park “Appennino Lucano, Val D'Agri, Lagonegrese” (Basilicata, southern Italy) was carried out, together with an evaluation of wild edible mushrooms in agro-forest ecosystems and their possible exploitation as a new source of food and revenue in rural and under-developed areas of this region. An unpublished list of 249 mushroom taxa (229 Basidiomycota and 20 Ascomycota), mostly belonging to the genera Tricholoma, Tuber, Russula, Amanita, Boletus, Lactarius, Mycena, Agaricus, Clitocybe and Hygrophorus, growing in this important natural area is provided together with ecological characterization of the recorded specimens. Inonotus obliquus is a new record for Basilicata, while Mycena bresadolana is reported for the first time from southern Italy. The presence of Amaurodon mustialaënsis, an extremely rare species of the northern hemisphere reported for the first time on white fir, is noteworthy. Among the previous findings, 116 species of edible mushrooms are presented and discussed in view of their relative abundance and edibility.     

3-Hydroxy-3-methylglutaric and 3-methylglutaric acids impair redox status and energy production and transfer in rat heart: relevance for the pathophysiology of cardiac dysfunction in 3-hydroxy-3-methylglutaryl-coenzyme A lyase deficiency

3-Hydroxy-3-methylglutaryl-coenzyme A lyase (HL) deficiency is characterized by tissue accumulation of 3-hydroxy-3-methylglutaric (HMG), and 3-methylglutaric (MGA) acids. Affected patients present cardiomyopathy, whose pathomechanisms are not yet established. We investigated the effects of HMG and MGA on energy and redox homeostasis in rat heart using in vivo and in vitro models. In vivo experiments showed that intraperitoneal administration of HMG and MGA decreased the activities of the respiratory chain complex II and creatine kinase (CK), whereas HMG also decreased the activity of complex II–III. Furthermore, HMG and MGA injection increased reactive species production and carbonyl formation, and decreased glutathione concentrations. Regarding the enzymatic antioxidant defenses, HMG and MGA increased glutathione peroxidase (GPx) and glutathione reductase (GR) activities, while only MGA diminished the activities of superoxide dismutase (SOD) and catalase, as well as the protein content of SOD1. Pre-treatment with melatonin (MEL) prevented MGA-induced decrease of CK activity and SOD1 levels. In vitro results demonstrated that HMG and MGA increased reactive species formation, induced lipid peroxidation and decreased glutathione. We also verified that reactive species overproduction and glutathione decrease provoked by HMG and MGA were abrogated by MEL and lipoic acid (LA), while only MEL prevented HMG- and MGA-induced lipoperoxidation. Allopurinol (ALP) also prevented reactive species overproduction caused by both metabolites. Our data provide solid evidence that bioenergetics dysfunction and oxidative stress are induced by HMG and MGA in heart, which may explain the cardiac dysfunction observed in HL deficiency, and also suggest that antioxidant supplementation could be considered as adjuvant therapy for affected patients.