Age and growth of the endemic Xingu River stingray Potamotrygon leopoldi validated using fluorescent dyes

Between 2003 and 2005, vertebrae of 151 Xingu River Potamotrygon leopoldi (Potamotrygonidae) (75 males and 76 females) were analysed to derive a growth curve for this species. The disc width (W _D) was significantly different between sexes, with females measuring 149–700 mm W _D and males 109–500 mm W _D. The average percentage error for vertebrae readings of the whole sample was 2·7%. The marginal increment ratio (R _MI) showed an increasing trend with the highest value in November, decreasing from December on. The majority of vertebrae displaying R _MI zero, occurred in September, but the annual periodicity of ring deposition throughout the year was not conclusive. Tetracycline (TCN) injected specimens were held in captivity for 13 months and displayed a fluorescent mark in vertebrae confirming a yearly periodicity of band pair formation with the translucent ring deposited in September–October. The Akaike information criterion (AIC) showed that, among the seven models considered, the best fit was obtained for the von Bertalanffy modified with W ₀ (where W ₀ = W _D at birth) for both sexes. Growth parameters for females were: W ₀ = 149 mm; W _∞ = 763·06 mm; k = 0·12 year^{– 1}, whereas for males: W ₀ = 109 mm; W _∞ = 536·4 and k = 0·22 year^?1. Maximal ages were 7·2 years in males and 14·3 years in females. The species shows sexual dimorphism expressed in the growth pattern, size at maturity, longevity and asymptotic sizes. Concern for sustainability is raised due to the construction of the Belo Monte Hydroelectric Power Plant (2015 and 2016) in the State of Pará causing changes to the habitat of this species, which is endemic to the Xingu River and two of its tributaries.     

Design,synthesis and evaluation of pterostilbene β-amino alcohol derivatives as multifunctional agents for Alzheimer's disease treatment

A series of pterostilbene β-amino alcohol derivatives were designed, synthesized and evaluated as multifunctional agents for the treatment of Alzheimer’s disease (AD). In vitro assays demonstrated that most of the derivatives were selective acetylacholinesterase (AChE) inhibitors with moderate multifunctional properties. Among them, compound 5f exhibited the best inhibitory activity for EeAChE (IC₅₀ = 24.04 μM), that was better than pterostilbene under our experimental condition. In addition, compound 5f displayed reasonable antioxidant activity and could confer significant neuroprotective effect against H₂O₂-induced PC-12 cell injury. Moreover, 5f also showed self-induced Aβ_1-42 aggregation inhibitory potency and displayed high BBB permeability in vitro. These multifunctional properties highlight 5f as a promising candidate for further studies directed to the development of novel drugs against AD.     

土地利用碳排放效应及其低碳管理研究进展

土地利用是造成全球温室气体排放量迅猛增长的重要因素,但由于土地利用的碳排放在时间和空间上受社会经济活动与自然过程的共同作用,相对自然生态系统碳排放的过程和机制更加复杂,因此,其研究也越来越多地受到包括学者、政府决策者、企业、非政府组织等利益相关者的关注,并被诸多能源与生态环境领域的国内外重大科学研究计划列为核心内容。通过对土地利用的直接和间接碳排放效应及其低碳管理的国内外研究进展进行综述,较全面地对上述研究中已取得的成果以及尚存在的不足与挑战进行了总结,并对未来研究应如何完善现有研究的不足提出了几点展望,以期为科学编制低碳目标导向的土地利用规划提供理论基础和实践管理经验,从而全面引导城市的低碳发展。     

Telomere length reveals cumulative individual and transgenerational inbreeding effects in a passerine bird

Inbreeding results in more homozygous offspring that should suffer reduced fitness, but it can be difficult to quantify these costs for several reasons. First, inbreeding depression may vary with ecological or physiological stress and only be detectable over long time periods. Second, parental homozygosity may indirectly affect offspring fitness, thus confounding analyses that consider offspring homozygosity alone. Finally, measurement of inbreeding coefficients, survival and reproductive success may often be too crude to detect inbreeding costs in wild populations. Telomere length provides a more precise measure of somatic costs, predicts survival in many species and should reflect differences in somatic condition that result from varying ability to cope with environmental stressors. We studied relative telomere length in a wild population of Seychelles warblers (Acrocephalus sechellensis) to assess the lifelong relationship between individual homozygosity, which reflects genome‐wide inbreeding in this species, and telomere length. In juveniles, individual homozygosity was negatively associated with telomere length in poor seasons. In adults, individual homozygosity was consistently negatively related to telomere length, suggesting the accumulation of inbreeding depression during life. Maternal homozygosity also negatively predicted offspring telomere length. Our results show that somatic inbreeding costs are environmentally dependent at certain life stages but may accumulate throughout life.     

Interactions among ecosystem stressors and their importance in conservation

Interactions between multiple ecosystem stressors are expected to jeopardize biological processes, functions and biodiversity. The scientific community has declared stressor interactions—notably synergies—a key issue for conservation and management. Here, we review ecological literature over the past four decades to evaluate trends in the reporting of ecological interactions (synergies, antagonisms and additive effects) and highlight the implications and importance to conservation. Despite increasing popularity, and ever-finer terminologies, we find that synergies are (still) not the most prevalent type of interaction, and that conservation practitioners need to appreciate and manage for all interaction outcomes, including antagonistic and additive effects. However, it will not be possible to identify the effect of every interaction on every organism''s physiology and every ecosystem function because the number of stressors, and their potential interactions, are growing rapidly. Predicting the type of interactions may be possible in the near-future, using meta-analyses, conservation-oriented experiments and adaptive monitoring. Pending a general framework for predicting interactions, conservation management should enact interventions that are robust to uncertainty in interaction type and that continue to bolster biological resilience in a stressful world.     

Probing the biological evaluations of a new designed Pt(II) complex using spectroscopic and theoretical approaches: human hemoglobin as a target

In recent years, using heavy metal compounds such as platinum as anticancer agent is one of the common ways in chemical therapy. In this study, a new anticancer compound of glycine derivatives of Pt(II) complex (amyl-glycine1, 10-phenanthroline Platinum nitrate) was designed, and the biological effects of this novel compound on the alterations in the function and structure of human hemoglobin (Hb) at different temperatures of 25 and 37°C were assessed by applying various spectroscopic (fluorescence and circular dichroism (CD)) and theoretical methods. Fluorescence data indicated the strong ability of Pt(II) complex to quench the intrinsic fluorescence of Hb. The binding constant, number of binding sites, and thermodynamic parameters at two temperatures were calculated, and the results indicated the major possibility of occurring van der Waals force or hydrogen bond interactions in the Pt(II) complex–Hb interaction. For evaluating the alteration of secondary structure of Hb upon interaction with various concentrations of complex, far-UV CD spectra were used and it was observed that in high dose of complex, significant changes were occurred which is indicative of some side effects in overdosing of this complex. On the other hand, the molecular docking results illustrate that are well in agreement in obtaining data with spectroscopy. Above results suggested that using Pt(II) complex as an anticancer agent, model drug in high-dose usage might cause some disordering in structure and function of Hb as well as improve understanding of the side effects of newly designed metal anticancer drugs undergoing.     

Differential Genomic Effects of Six Different TiO2 Nanomaterials on Human Liver HepG2 Cells

Human HepG2 cells were exposed to six TiO₂ nanomaterials (with dry primary particle sizes ranging from 22 to 214 nm, either 0.3, 3, or 30 μg/mL) for 3 days. Some of these canonical pathways changed by nano‐TiO₂ in vitro treatments have been already reported in the literature, such as NRF2‐mediated stress response, fatty acid metabolism, cell cycle and apoptosis, immune response, cholesterol biosynthesis, and glycolysis. But this genomic study also revealed some novel effects such as protein synthesis, protein ubiquitination, hepatic fibrosis, and cancer‐related signaling pathways. More importantly, this genomic analysis of nano‐TiO₂ treated HepG2 cells linked some of the in vitro canonical pathways to in vivo adverse outcomes: NRF2‐mediated response pathways to oxidative stress, acute phase response to inflammation, cholesterol biosynthesis to steroid hormones alteration, fatty acid metabolism changes to lipid homeostasis alteration, G2/M cell checkpoint regulation to apoptosis, and hepatic fibrosis/stellate cell activation to liver fibrosis.     

Global ecological impacts of invasive species in aquatic ecosystems

The introduction of invasive species, which often differ functionally from the components of the recipient community, generates ecological impacts that propagate along the food web. This review aims to determine how consistent the impacts of aquatic invasions are across taxa and habitats. To that end, we present a global meta‐analysis from 151 publications (733 cases), covering a wide range of invaders (primary producers, filter collectors, omnivores and predators), resident aquatic community components (macrophytes, phytoplankton, zooplankton, benthic invertebrates and fish) and habitats (rivers, lakes and estuaries). Our synthesis suggests a strong negative influence of invasive species on the abundance of aquatic communities, particularly macrophytes, zooplankton and fish. In contrast, there was no general evidence for a decrease in species diversity in invaded habitats, suggesting a time lag between rapid abundance changes and local extinctions. Invaded habitats showed increased water turbidity, nitrogen and organic matter concentration, which are related to the capacity of invaders to transform habitats and increase eutrophication. The expansion of invasive macrophytes caused the largest decrease in fish abundance, the filtering activity of filter collectors depleted planktonic communities, omnivores (including both facultative and obligate herbivores) were responsible for the greatest decline in macrophyte abundance, and benthic invertebrates were most negatively affected by the introduction of new predators. These impacts were relatively consistent across habitats and experimental approaches. Based on our results, we propose a framework of positive and negative links between invasive species at four trophic positions and the five different components of recipient communities. This framework incorporates both direct biotic interactions (predation, competition, grazing) and indirect changes to the water physicochemical conditions mediated by invaders (habitat alteration). Considering the strong trophic links that characterize aquatic ecosystems, this framework is relevant to anticipate the far‐reaching consequences of biological invasions on the structure and functionality of aquatic ecosystems.     

Relative male and female contributions to the supercooling point of their offspring in Microvelia reticulata (Heteroptera: Veliidae)

Cold hardiness is a key life history trait in temperate and polar ectothermic species, as it affects survival during overwintering, but its evolution is poorly understood. While many studies of cold hardiness in insects have shown differences between species, populations or developmental stages, data on the relative contribution of individual genotypes to cold hardiness are scarce and mainly limited to drosophilid fly species. We used a sib‐analysis (paternal half‐sib/full‐sib breeding design) to estimate the relative contributions of parental generation to the supercooling point (SCP) of the offspring of a heteropteran non‐model insect species, Microvelia reticulata (Heteroptera: Gerromorpha: Veliidae). We found that parent identity affected significantly SCP values of their offspring. Magnitudes of estimated sire and dam variance components were similar but the distributions of individual contributions to SCP differed between sires and dams, which points to sex‐specific genetic or parental effects on SCP in this species. The animal model failed to find a realistic estimate of heritability (h²) of SCP, suggesting that the underlying genetics of SCP in M. reticulata can not be characterized by purely additive effects.