Comparative egg morphology of six Meccus species and Triatoma recurva (Stål, 1868) Hemiptera: Reduviidae

We investigated the morphology and morphometry of eggs from the colonies of the Entomology Laboratory at ENCB‐IPN belonging to six species of the genus Meccus and Triatoma recurva, using both light and scanning electron microscopy. Egg ornamentation is an important parameter to consider in the differentiation of species. Samples were observed under a scanning electron microscope. Measurements of fifty eggs per species included length, width, and opercular diameter, which were used for the morphometric analysis. The results showed that the seven species display a polygonal ornamentation dominated by hexagons; the operculum shows also a polygonal ornamental characteristic in each species. Morphometry provided valuable information for discriminating between closely related species of the genus Meccus and Triatoma recurva, a species akin to this group, thereby facilitating the complete discrimination of these species.     

Climate and land use changes will degrade the configuration of the landscape for titi monkeys in eastern Brazil

Land use changes have profound effects on populations of Neotropical primates, and ongoing climate change is expected to aggravate this scenario. The titi monkeys from eastern Brazil (Callicebus personatus group) have been particularly affected by this process, with four of the five species now allocated to threatened conservation status categories. Here, we estimate the changes in the distribution of these titi monkeys caused by changes in both climate and land use. We also use demographic‐based, functional landscape metrics to assess the magnitude of the change in landscape conditions for the distribution predicted for each species. We built species distribution models (SDMs) based on maximum entropy for current and future conditions (2070), allowing for different global circulation models and contrasting scenarios of glasshouse gas concentrations. We refined the SDMs using a high‐resolution map of habitat remnants. We then calculated habitat availability and connectivity based on home‐range size and the dispersal limitations of the individual, in the context of a predicted loss of 10% of forest cover in the future. The landscape configuration is predicted to be degraded for all species, regardless of the climatic settings. This include reductions in the total cover of forest remnants, patch size and functional connectivity. As the landscape configuration should deteriorate severely in the future for all species, the prevention of further loss of populations will only be achieved through habitat restoration and reconnection to counteract the negative effects for these and several other co‐occurring species.     

Storage elicits a fast antioxidant enzyme activity in <Emphasis Type="Italic">Araucaria angustifolia</Emphasis> embryos

Storage of recalcitrant seeds leads to the initiation of subcellular damage or to the initiation of germination process, and both may result in viability loss. This study aimed to elucidate the biochemical basis of embryos survival of Araucaria angustifolia recalcitrant seeds during storage. After harvesting, seeds were stored at ambient conditions (without temperature and humidity control) and in a cold chamber (temperature of 10 ± 3 °C, and relative humidity of 45 ± 5 %). Moisture content, viability, H₂O₂ content, lipid peroxidation, protein content, and activities of the antioxidant enzymes superoxide dismutase (SOD), catalase (CAT) and ascorbate peroxidase (APX), at 0, 15, 45 and 90 days of storage, were evaluated. Seed viability reduced about 40 % during the storage period accompanied by a reduction in soluble protein (about 64 % of reduction) in both storage conditions, and increased lipid peroxidation (about 115 % and 66 % for ambient and cold chamber conditions, respectively). H₂O₂ content used as a marker of oxidative stress was reduced during the period, possibly controlled by the action of CAT and APX, for which increased activities were observed. The results allowed the identification of seven SOD isoenzymes (one Mn-SOD, five Fe-SOD and one Cu/Zn-SOD), whose activities also increased in response to storage. Some biochemical damage resulting from storage was observed, but viability reduction was not due to failure of enzymatic protection mechanisms.     

Comment on ‘Island biogeography: patterns of marine shallow‐water organisms’ by Hachich et al., Journal of Biogeography (2015)

In a recent article, Hachich et al. (2015, Journal of Biogeography, 42 , 1871–1882) studied the large‐scale biogeographical patterns of the species–area, species–island age and species–isolation relationships associated with marine shallow‐water groups (reef fish, gastropods and seaweeds) from 11 Atlantic archipelagos. We here express our concerns regarding the data accuracy used to compute the different models that tested the null hypothesis of species richness being independent of the selected variables. In our commentary, we focus mainly on the use of out‐of‐date checklists of gastropod and seaweed species from different archipelagos, but we also point out inaccuracies in some island age estimates and explain our disagreement with the use of the 200 m depth limit for the shallow‐water gastropods and seaweeds.     

Optimization of protein–protein docking for predicting Fc–protein interactions

The antibody crystallizable fragment (Fc) is recognized by effector proteins as part of the immune system. Pathogens produce proteins that bind Fc in order to subvert or evade the immune response. The structural characterization of the determinants of Fc–protein association is essential to improve our understanding of the immune system at the molecular level and to develop new therapeutic agents. Furthermore, Fc‐binding peptides and proteins are frequently used to purify therapeutic antibodies. Although several structures of Fc–protein complexes are available, numerous others have not yet been determined. Protein–protein docking could be used to investigate Fc–protein complexes; however, improved approaches are necessary to efficiently model such cases. In this study, a docking‐based structural bioinformatics approach is developed for predicting the structures of Fc–protein complexes. Based on the available set of X‐ray structures of Fc–protein complexes, three regions of the Fc, loosely corresponding to three turns within the structure, were defined as containing the essential features for protein recognition and used as restraints to filter the initial docking search. Rescoring the filtered poses with an optimal scoring strategy provided a success rate of approximately 80% of the test cases examined within the top ranked 20 poses, compared to approximately 20% by the initial unrestrained docking. The developed docking protocol provides a significant improvement over the initial unrestrained docking and will be valuable for predicting the structures of currently undetermined Fc–protein complexes, as well as in the design of peptides and proteins that target Fc.     

A synergistic trio of invasive mammals? Facilitative interactions among beavers,muskrats, and mink at the southern end of the Americas

With ecosystems increasingly having co-occurring invasive species, it is becoming more important to understand invasive species interactions. At the southern end of the Americas, American beavers (Castor canadensis), muskrats (Ondatra zibethicus), and American mink (Neovison vison), were independently introduced. We used generalized linear models to investigate how muskrat presence related to beaver-modified habitats on Navarino Island, Chile. We also investigated the trophic interactions of the mink with muskrats and beavers by studying mink diet. Additionally, we proposed a conceptual species interaction framework involving these invasive species on the new terrestrial community. Our results indicated a positive association between muskrat presence and beaver-modified habitats. Model average coefficients indicated that muskrats preferred beaver-modified freshwater ecosystems, compared to not dammed naturally flowing streams. In addition, mammals and fish represented the main prey items for mink. Although fish were mink’s dominant prey in marine coastal habitats, muskrats represented >50 % of the biomass of mink diet in inland environments. We propose that beavers affect river flow and native vegetation, changing forests into wetlands with abundant grasses and rush vegetation. Thus, beavers facilitate the existence of muskrats, which in turn sustain inland mink populations. The latter have major impacts on the native biota, especially on native birds and small rodents. The facilitative interactions among beavers, muskrats, and mink that we explored in this study, together with other non-native species, suggest that an invasive meltdown process may exist; however further research is needed to confirm this hypothesis. Finally, we propose a community-level management to conserve the biological integrity of native ecosystems.