Coevolutionary relationship between striatum size and social play in nonhuman primates

The striatum is a region of the brain specifically tied to the experience and anticipation of pleasure, reward, appropriate behavioral sequencing, cognition, learning, and social modulation. Furthermore, the striatum is connected neurologically and functionally to other brain regions associated with the exhibition of social play, such as the neocortex, cerebellum, and limbic system. For these reasons, the striatum is especially interesting to researchers of play behavior. Moreover, the caudate-putamen area of the striatum has been specifically implicated in laboratory studies of social play behavior. This study uses the phylogenetic comparative method of independent contrasts to test for an evolutionary relationship between striatum volume and a measure of social play in nonhuman primates. Relative volume of the primate striatum correlates with rate of social, but not nonsocial, play behavior across species, suggesting a coevolution of traits. The pleasurable and procedural aspects of social play behavior may be mediated in part by the striatum and further to its connection to dopaminergic pathways in the primate brain.     

Ceramides induce programmed cell death in Arabidopsis cells in a calcium-dependent manner

While the role of C2-ceramide in the induction of programmed cell death (PCD) in animal systems has been well documented, little is known of its role in plant cells. Here we show that C2-ceramide induces PCD in Arabidopsis suspension cultures, which is preceded by the generation of a calcium transient and an increase in reactive oxygen species (ROS). Inhibition of the calcium transient prevented cell death, whereas inhibition of ROS had no effect on cell survival. These observations suggest that calcium signalling plays a role in ceramide-induced PCD but is independent of the generation of ROS.     

Water availability drives aboveground biomass and bird richness in forest restoration plantings to achieve carbon and biodiversity cobenefits

To combat global warming and biodiversity loss, we require effective forest restoration that encourages recovery of species diversity and ecosystem function to deliver essential ecosystem services, such as biomass accumulation. Further, understanding how and where to undertake restoration to achieve carbon sequestration and biodiversity conservation would provide an opportunity to finance ecosystem restoration under carbon markets. We surveyed 30 native mixed‐species plantings in subtropical forests and woodlands in Australia and used structural equation modeling to determine vegetation, soil, and climate variables most likely driving aboveground biomass accrual and bird richness and investigate the relationships between plant diversity, aboveground biomass accrual, and bird diversity. We focussed on woodland and forest‐dependent birds, and functional groups at risk of decline (insectivorous, understorey‐nesting, and small‐bodied birds). We found that mean moisture availability strongly limits aboveground biomass accrual and bird richness in restoration plantings, indicating potential synergies in choosing sites for carbon and biodiversity purposes. Counter to theory, woody plant richness was a poor direct predictor of aboveground biomass accrual, but was indirectly related via significant, positive effects of stand density. We also found no direct relationship between aboveground biomass accrual and bird richness, likely because of the strong effects of moisture availability on both variables. Instead, moisture availability and patch size strongly and positively influenced the richness of woodland and forest‐dependent birds. For understorey‐nesting birds, however, shrub cover and patch size predicted richness. Stand age or area of native vegetation surrounding the patch did not influence bird richness. Our results suggest that in subtropical biomes, planting larger patches to higher densities, ideally using a diversity of trees and shrubs (characteristics of ecological plantings) in more mesic locations will enhance the provision of carbon and biodiversity cobenefits. Further, ecological plantings will aid the rapid recovery of woodland and forest bird richness, with comparable aboveground biomass accrual to less diverse forestry plantations.     

Dietary cholesterol alters Na+/K+ selectivity at intracellular Na+/K+ pump sites in cardiac myocytes

A modest diet-induced increase in serum cholesterol in rabbits increases the sensitivity of the sarcolemmal Na⁺/K⁺ pump to intracellular Na⁺, whereas a large increase in cholesterol levels decreases the sensitivity to Na⁺. To examine the mechanisms, we isolated cardiac myocytes from controls and from rabbits with diet-induced increases in serum cholesterol. The myocytes were voltage clamped with the use of patch pipettes that contained osmotically balanced solutions with Na⁺ in a concentration of 10 mM and K⁺ in concentrations ([K⁺]_pip) ranging from 0 to 140 mM. There was no effect of dietary cholesterol on electrogenic Na⁺/K⁺ current (I_p) when pipette solutions were K⁺ free. A modest increase in serum cholesterol caused a [K⁺]_pip-dependent increase in I_p, whereas a large increase caused a [K⁺]_pip-dependent decrease in I_p. Modeling suggested that pump stimulation with a modest increase in serum cholesterol can be explained by a decrease in the microscopic association constant K_K describing the backward reaction E₁ + 2K⁺ E₂(K⁺)₂, whereas pump inhibition with a large increase in serum cholesterol can be explained by an increase in K_K. Because hypercholesterolemia upregulates angiotensin II receptors and because angiotensin II regulates the Na⁺/K⁺ pump in cardiac myocytes in a [K⁺]_pip-dependent manner, we blocked angiotensin synthesis or angiotensin II receptors in vivo in cholesterol-fed rabbits. This abolished cholesterol-induced pump inhibition. Because the -isoform of protein kinase C (PKC) mediates effects of angiotensin II on the pump, we included specific PKC-blocking peptide in patch pipette filling solutions. The peptide reversed cholesterol-induced pump inhibition. partial reactions; protein kinase C; angiotensin converting enzyme inhibitors; arteriosclerosis; insulin resistance     

Bayesian Nonparametric Modeling Using Mixtures of Triangular Distributions

Nonparametric modeling is an indispensable tool in many applications and its formulation in an hierarchical Bayesian context, using the entire posterior distribution rather than particular expectations, increases its flexibility. In this article, the focus is on nonparametric estimation through a mixture of triangular distributions. The optimality of this methodology is addressed and bounds on the accuracy of this approximation are derived. Although our approach is more widely applicable, we focus for simplicity on estimation of a monotone nondecreasing regression on [0, 1] with additive error, effectively approximating the function of interest by a function having a piecewise linear derivative. Computationally accessible methods of estimation are described through an amalgamation of existing Markov chain Monte Carlo algorithms. Simulations and examples illustrate the approach.     

Production Factors Controlling the Physical Characteristics of Biochar Derived from Phytoremediation Willow for Agricultural Applications

Willow, a leading bioenergy feedstock, may be planted for bioremediation and has been used, more recently, as the biomass feedstock in the manufacture of biochar for agricultural applications. Here, we present a detailed study of the physical and chemical factors affecting willow char properties, where the feedstock is a by-product of bioremediation, potentially transferring pollutants such as heavy metals to the wood feed. Biochar samples were produced via pyrolysis of short-rotation coppice willow, grown on contaminated land, using several treatment times at heat treatment temperatures (HTTs) in the range 350–650 °C, under a constant flow of argon, set at either 100 or 500 mL min^?1. The samples were analysed for yield, elemental analysis and structural characteristics, including surface area and pore size distribution, surface functionality and metal content. All chars obtained have high fixed carbon contents but vary in surface characteristics with a marked increase in basic character with increasing HTT, ascribed to the removal of surface oxygen moieties. Results indicate a minimum pyrolysis temperature of 450 °C is required to produce a defined mesoporous structure, as required to facilitate oxygen transport, HTT?≥?550 °C produces total surface area of >170 m² g^?1 and, more importantly, an appreciable external surface area suitable for microbial colonisation. The data show that selection and optimisation of char properties is possible; however, the interplay of factors may mean some compromise is required.     

Involvement of the Kynurenine Pathway in Human Glioma Pathophysiology

The kynurenine pathway (KP) is the principal route of L-tryptophan (TRP) catabolism leading to the production of kynurenine (KYN), the neuroprotectants, kynurenic acid (KYNA) and picolinic acid (PIC), the excitotoxin, quinolinic acid (QUIN) and the essential pyridine nucleotide, nicotinamide adenine dinucleotide (NAD⁺). The enzymes indoleamine 2,3-dioxygenase-1 (IDO-1), indoleamine 2,3-dioxygenase-2 (IDO-2) and tryptophan 2,3-dioxygenase (TDO-2) initiate the first step of the KP. IDO-1 and TDO-2 induction in tumors are crucial mechanisms implicated to play pivotal roles in suppressing anti-tumor immunity. Here, we report the first comprehensive characterisation of the KP in 1) cultured human glioma cells and 2) plasma from patients with glioblastoma (GBM). Our data revealed that interferon-gamma (IFN-γ) stimulation significantly potentiated the expression of the KP enzymes, IDO-1 IDO-2, kynureninase (KYNU), kynurenine hydroxylase (KMO) and significantly down-regulated 2-amino-3-carboxymuconate semialdehyde decarboxylase (ACMSD) and kynurenine aminotransferase-I (KAT-I) expression in cultured human glioma cells. This significantly increased KP activity but significantly lowered the KYNA/KYN neuroprotective ratio in human cultured glioma cells. KP activation (KYN/TRP) was significantly higher, whereas the concentrations of the neuroreactive KP metabolites TRP, KYNA, QUIN and PIC and the KYNA/KYN ratio were significantly lower in GBM patient plasma (n = 18) compared to controls. These results provide further evidence for the involvement of the KP in glioma pathophysiology and highlight a potential role of KP products as novel and highly attractive therapeutic targets to evaluate for the treatment of brain tumors, aimed at restoring anti-tumor immunity and reducing the capacity for malignant cells to produce NAD⁺, which is necessary for energy production and DNA repair.     

The effect of carbon credits on savanna land management and priorities for biodiversity conservation

Carbon finance offers the potential to change land management and conservation planning priorities. We develop a novel approach to planning for improved land management to conserve biodiversity while utilizing potential revenue from carbon biosequestration. We apply our approach in northern Australia's tropical savanna, a region of global significance for biodiversity and carbon storage, both of which are threatened by current fire and grazing regimes. Our approach aims to identify priority locations for protecting species and vegetation communities by retaining existing vegetation and managing fire and grazing regimes at a minimum cost. We explore the impact of accounting for potential carbon revenue (using a carbon price of US$14 per tonne of carbon dioxide equivalent) on priority areas for conservation and the impact of explicitly protecting carbon stocks in addition to biodiversity. Our results show that improved management can potentially raise approximately US$5 per hectare per year in carbon revenue and prevent the release of 1-2 billion tonnes of carbon dioxide equivalent over approximately 90 years. This revenue could be used to reduce the costs of improved land management by three quarters or double the number of biodiversity targets achieved and meet carbon storage targets for the same cost. These results are based on generalised cost and carbon data; more comprehensive applications will rely on fine scale, site-specific data and a supportive policy environment. Our research illustrates that the duel objective of conserving biodiversity and reducing the release of greenhouse gases offers important opportunities for cost-effective land management investments.