Obesity-induced tissue free radical generation: an in vivo immuno-spin trapping study

Assessment of tissue free radical production is routinely accomplished by measuring secondary by-products of redox reactions and/or diminution of key antioxidants such as reduced thiols. However, immuno-spin trapping, a newly developed immunohistochemical technique for detection of free radical formation, is garnering considerable interest as it allows for the visualization of 5,5-dimethyl-1-pyrroline N-oxide (DMPO)-adducted molecules. Yet, to date, immuno-spin trapping reports have utilized in vivo models in which successful detection of free radical adducts required exposure to lethal levels of oxidative stress not reflective of chronic inflammatory disease. To study the extents and anatomic locations of more clinically relevant levels of radical formation, we examined tissues from high-fat (HF) diet-fed mice, a model of low-grade chronic inflammation known to demonstrate enhanced rates of reactive species production. Mice subjected to 20 weeks of HF diet displayed increased free radical formation (anti-DMPO mean fluorescence staining) in skeletal muscle (0.863±0.06 units vs 0.512±0.07 units), kidney (0.076±0.0036 vs 0.043±0.0025), and liver (0.275±0.012 vs 0.135±0.014) compared to control mice fed normal laboratory chow (NC). Western blot analysis of tissue homogenates confirmed these results showing enhanced DMPO immunoreactivity in HF mice compared to NC samples. The obesity-related results were confirmed in a rat model of pulmonary hypertension and right heart failure in which intense immunodetectable radical formation was observed in the lung and right ventricle of monocrotaline-treated rats compared to saline-treated controls. Combined, these data affirm the utility of immuno-spin trapping as a tool for in vivo assessment of altered extents of macromolecule oxidation to radical intermediates under chronic inflammatory conditions.     

The Molecular Machinery of Gametogenesis in Geodia Demosponges (Porifera): Evolutionary Origins of a Conserved Toolkit across Animals

All animals are capable of undergoing gametogenesis. The ability of forming haploid cells from diploid cells through meiosis and recombination appeared early in eukaryotes, whereas further gamete differentiation is mostly a metazoan signature. Morphologically, the gametogenic process presents many similarities across animal taxa, but little is known about its conservation at the molecular level. Porifera are the earliest divergent animals and therefore are an ideal phylum to understand evolution of the gametogenic toolkits. Although sponge gametogenesis is well known at the histological level, the molecular toolkits for gamete production are largely unknown. Our goal was to identify the genes and their expression levels which regulate oogenesis and spermatogenesis in five gonochoristic and oviparous species of the genus Geodia, using both RNAseq and proteomic analyses. In the early stages of both female and male gametogenesis, genes involved in germ cell fate and cell-renewal were upregulated. Then, molecular signals involved in retinoic acid pathway could trigger the meiotic processes. During later stages of oogenesis, female sponges expressed genes involved in cell growth, vitellogenesis, and extracellular matrix reassembly, which are conserved elements of oocyte maturation in Metazoa. Likewise, in spermatogenesis, genes regulating the whole meiotic cycle, chromatin compaction, and flagellum axoneme formation, that are common across Metazoa were overexpressed in the sponges. Finally, molecular signals possibly related to sperm capacitation were identified during late stages of spermatogenesis for the first time in Porifera. In conclusion, the activated molecular toolkit during gametogenesis in sponges was remarkably similar to that deployed during gametogenesis in vertebrates.     

Differential antioxidant protection in tissues from marine mammals with distinct diving capacities. Shallow/short vs. deep/long divers

The diving response in marine mammals results in bradycardia and peripheral vasoconstriction, with blood flow redistributing preferentially to nervous and cardiac tissues. Therefore, some tissues are rendered ischemic during a dive; with the first breath after a dive, blood flow to all tissues is reestablished. In terrestrial mammals, reactive oxygen species (ROS) production increases in response to ischemia/reperfusion and oxidative damage can occur. The capacity of marine mammals to tolerate repeated ischemia/reperfusion cycles associated with diving appears to be due to an enhanced antioxidant system. However, it is not known if diving depth and/or duration elicit differences in tissue capacity to produce ROS and antioxidant defenses in marine mammals. The objective of this study was to analyze ROS production, antioxidant defenses and oxidative damage in marine mammal species that perform shallow/short vs. deep/long dives. We measured production of superoxide radical (O₂^??), oxidative damage to lipids and proteins, activity of antioxidant enzymes, and glutathione levels in tissues from shallow/short divers (Tursiops truncatus) and deep/long divers (Kogia spp.). We found that differences between the diving capacity of dolphins and Kogia spp. are reflected in O₂^?? production and antioxidant levels. These differences suggest that shallow/short and deep/long divers have distinct mechanisms to successfully maintain redox balance.     

Securin and separase modulate membrane traffic by affecting endosomal acidification

Securin and separase play a key role in sister chromatid separation during anaphase. However, a growing body of evidence suggests that in addition to regulating chromosome segregation, securin and separase display functions implicated in membrane traffic in Caenorhabditis elegans and Drosophila. Here we show that in mammalian cells both securin and separase associate with membranes and that depletion of either protein causes robust swelling of the trans-Golgi network (TGN) along with the appearance of large endocytic vesicles in the perinuclear region. These changes are accompanied by diminished constitutive protein secretion as well as impaired receptor recycling and degradation. Unexpectedly, cells depleted of securin or separase display defective acidification of early endosomes and increased membrane recruitment of vacuolar (V-) ATPase complexes, mimicking the effect of the specific V-ATPase inhibitor Bafilomycin A1. Taken together, our findings identify a new functional role of securin and separase in the modulation of membrane traffic and protein secretion that implicates regulation of V-ATPase assembly and function.     

Recently discovered landlocked basins in Indonesia reveal high habitat diversity in anchialine systems

In this article, the variability of physical settings of anchialine systems in Indonesia is discussed together with the consequences these settings have for the environment and biota within the systems. Exploration in two karstic areas (Berau, East Kalimantan and Raja Ampat, West Papua) has resulted in the discovery of 20 previously unknown anchialine systems in Indonesia. Based on parameters such as bathymetry, size, coastline, salinity, water temperature, pH, degree of connection to the sea, and the presence-absence of selected key taxa we distinguish three types of (non-cave) anchialine systems in the Indo-Pacific: (1) Marine lakes with large and deep basins containing brackish to almost fully marine waters. Marine lakes show a range in the degree of connection to the sea with the result that the higher the connection the more the lake resembles a lagoon in both water chemistry and biota, while the more isolated lakes have brackish water and contain unique species that are rarely found in the adjacent sea. (2) Anchialine pools with small and shallow basins containing brackish water and low diversity of macrofauna. (3) Blue pools in chasms that contain water with a clear halocline and are possibly connected to anchialine caves. Study of the many unique features of anchialine systems will enhance our understanding of the physical and ecological processes responsible for diversification in tropical shallow marine environments.     

Understanding the murky history of the Coral Triangle: Miocene corals and reef habitats in East Kalimantan (Indonesia)

Studies on ancient coral communities living in marginal conditions, including low light, high turbidity, extreme temperatures, or high nutrients, are important to understand the current structure of reefs and how they could potentially respond to global changes. The main goal of this study was to document the rich and well-preserved fossil coral fauna preserved in Miocene exposures of the Kutai Basin in East Kalimantan, Indonesia. Our collections include almost forty thousand specimens collected from 47 outcrops. Seventy-nine genera and 234 species have been identified. Three different coral assemblages were found corresponding to small patch reefs that developed under the influence of high siliciclastic inputs from the Mahakam Delta. Coral assemblages vary in richness, structure, and composition. Platy coral assemblages were common until the Serravallian (Middle Miocene), while branching coral assemblages became dominant in the Tortonian (Late Miocene). By the late Tortonian massive coral assemblages dominated, similar to modern-style coral framework. Our results suggest that challenging habitats, such as the Miocene turbid habitats of East Kalimantan, might have played an important role during the early diversification of the Coral Triangle by hosting a pool of resilient species more likely to survive the environmental changes that have affected this region since the Cenozoic. Further research that integrates fossil and recent turbid habitats may provide a glimpse into the dynamics and future of coral reefs as “typical” clear-water reefs continue to decline in most regions.     

Calcium dynamics in catecholamine-containing secretory vesicles

We have used an aequorin chimera targeted to the membrane of the secretory granules to monitor the free [Ca(2+)] inside them in neurosecretory PC12 cells. More than 95% of the probe was located in a compartment with an homogeneous [Ca(2+)] around 40 microM. Cell stimulation with either ATP, caffeine or high-K(+) depolarization increased cytosolic [Ca(2+)] and decreased secretory granule [Ca(2+)] ([Ca(2+)](SG)). Inositol-(1,4,5)-trisphosphate, cyclic ADP ribose and nicotinic acid adenine dinucleotide phosphate were all ineffective to release Ca(2+) from the granules. Changes in cytosolic [Na(+)] (0-140 mM) or [Ca(2+)] (0-10 microM) did not modify either ([Ca(2+)](SG)). Instead, [Ca(2+)](SG) was highly sensitive to changes in the pH gradient between the cytosol and the granules. Both carbonyl cyanide 4-(trifluoromethoxy)phenylhydrazone (FCCP) and nigericin, as well as cytosolic acidification, reversibly decreased [Ca(2+)](SG), while cytosolic alcalinization reversibly increased [Ca(2+)](SG). These results are consistent with the operation of a H(+)/Ca(2+) antiporter in the vesicular membrane. This antiporter could also mediate the effects of ATP, caffeine and high-K(+) on [Ca(2+)](SG), because all of them induced a transient cytosolic acidification. The FCCP-induced decrease in [Ca(2+)](SG) was reversible in 10-15 min even in the absence of cytosolic Ca(2+) or ATP, suggesting that most of the calcium content of the vesicles is bound to a slowly exchanging Ca(2+) buffer. This large store buffers [Ca(2+)](SG) changes in the long-term but allows highly dynamic free [Ca(2+)](SG) changes to occur in seconds or minutes.     

Global risk levels for corn rusts (Puccinia sorghi and Puccinia polysora) under climate change projections

Common rust (Puccinia sorghi) and southern rust (Puccinia polysora) are two of the most important foliar corn diseases worldwide. These fungi have caused severe economic loss to corn yields worldwide. The current and future potential distribution of these diseases was modelled with CLIMEX using the known current geographic locations of the rusts, growth and stress indices. The models were run under the A2 scenario using CSIRO‐Mk3·0 and MIROC‐H for 2050 and 2100. The current projection shows areas with marginal to optimal suitability in all the continents. The models for future projections display a general reduction in the Southern hemisphere and increase in the Northern hemisphere, especially for the southern rust. The overlay of the General Circulation Models produce an estimation of the common areas under risk for future climate conditions for the simultaneous occurrence for both corn rusts, with a reduction of the medium‐ and high‐risk categories by 2100. This study highlights the possible effects of climate change at a global level for common and southern rust, as well as the risk of occurrence of both diseases in common areas for future climate that could be particularly harmful for crops.