Differences in Fecal Androgen Patterns of Breeding and Nonbreeding Kori Bustards (Ardeotis kori)

To better understand breeding conditions to promote reproduction in captive kori bustards, fundamental endocrine studies measuring fecal androgen metabolites in male and female kori bustards were conducted. Feces collected weekly from males and females were analyzed for testosterone using enzyme‐linked immunoassay. Results from adult males (n = 5), adult females (n = 10), immature males (n = 10), and immature females (n = 10) revealed seasonally elevated testosterone concentrations in fertile, but not nonfertile adult males and females (P > 0.05). Adult females that were not maintained in a breeding group, or that did not produce eggs, did not demonstrate increases in testosterone compared to egg laying counterparts. In males, but not females, seasonal testosterone increases were accompanied by weight gain. Peaks in male fecal androgen metabolites ranged from 10‐ to 22‐fold higher than nonbreeding season (181.5 ± 19.1 vs. 17.0 ± 0.94 ng/g; P < 0.05). Mean breeding season values for adult males were 83.6 ± 6.1 ng/g vs. nonbreeding season values of 12.3 ± 0.73 ng/g (P < 0.05). In females, average breeding season testosterone concentrations were approximately 4‐fold higher than nonbreeding season (55.9 ± 6.0 vs. 14.5 ± 1.8 ng/g), with peaks 10‐ to 30‐fold higher. Results show that noninvasive fecal androgen metabolite analysis can provide a means of predicting fertility potential of male and female kori bustards and might be utilized to assess effects of modifying captive environments to promote reproduction in this species. Zoo Biol. 32:54‐62, 2013. © 2012 Wiley Periodicals, Inc.     

Chronic Nicotine Treatment Impacts the Regulation of Opioid and Non-opioid Peptides in the Rat Dorsal Striatum

The chronic use of nicotine, the main psychoactive ingredient of tobacco smoking, alters diverse physiological processes and consequently generates physical dependence. To understand the impact of chronic nicotine on neuropeptides, which are potential molecules associated with dependence, we conducted qualitative and quantitative neuropeptidomics on the rat dorsal striatum, an important brain region implicated in the preoccupation/craving phase of drug dependence. We used extensive LC-FT-MS/MS analyses for neuropeptide identification and LC-FT-MS in conjunction with stable isotope addition for relative quantification. The treatment with chronic nicotine for 3 months led to moderate changes in the levels of endogenous dorsal striatum peptides. Five enkephalin opioid peptides were up-regulated, although no change was observed for dynorphin peptides. Specially, nicotine altered levels of nine non-opioid peptides derived from precursors, including somatostatin and cerebellin, which potentially modulate neurotransmitter release and energy metabolism. This broad but selective impact on the multiple peptidergic systems suggests that apart from the opioid peptides, several other peptidergic systems are involved in the preoccupation/craving phase of drug dependence. Our finding permits future evaluation of the neurochemical circuits modulated by chronic nicotine exposure and provides a number of novel molecules that could serve as potential therapeutic targets for treating drug dependence.Nicotine is the main psychoactive ingredient of tobacco (1). By acting on the nicotinic acetylcholine receptors located in diverse brain areas, nicotine generates psychoactive effects such as euphoria, reduced stress, increased energy, and enhanced cognitive functions (2). Chronic nicotine use alters various aspects of neurochemical transmission and has a strong impact on diverse physiological processes (2), resulting in drug-seeking and drug-taking behaviors for normal smokers and for a considerable number of patients suffering from schizophrenia and Alzheimer disease, who use nicotine for self-medication (3, 4). The dorsal striatum (DS)¹ is one of the key brain regions that has been associated with neural regulation during chronic nicotine exposure (5). In particular, the DS is involved in habit formation during the preoccupation/craving (later) phase of nicotine dependence characterized by compulsive drug-taking (6). Behavioral changes associated with nicotine dependence have been linked to small molecule neurotransmitter systems, including the glutamate and dopamine system in the DS (7). The DS is also known to contain diverse neuropeptides, many of which are probably critical mediators of physiological processes that are associated with nicotine, such as the regulation of reinforcement and energy metabolism. However, neuropeptides have not been extensively investigated in the DS during long periods of nicotine administration.Immunoassay studies have shown that neuropeptides, including substance P, neuropeptide Y, and opioid peptides, including the enkephalins, are expressed by inhibitory neurons (8), which make up a large majority of the neurons in the DS (9). Many of these inhibitory GABAergic neurons express nicotinic cholinergic receptors (10), suggesting that nicotine administration may regulate their activity, leading to variations in the release of neuropeptides, as well as the inhibitory neurotransmitter GABA. Previous investigations of peptide regulation during chronic nicotine administration in the striatum have exclusively focused on the class of opioid peptides, which are thought to play an important role in the control of diverse physiological processes, including reward processing, nociception, and regulation of emotions (11, 12). Available studies have focused on the analysis of three opioid peptides, their precursors, or receptors as follows: met-enkephalin, dynorphin, and β-endorphin, using conventional techniques like immunoassays (13, 14). There is considerable variability in reported changes of peptide levels in the striatum during chronic nicotine administration. For example, when animals are treated with 1 mg/kg free base nicotine (daily for 14 days), met-enkephalin increased in the striatum (15). By contrast, met-enkephalin is reduced in the striatum when rats are treated with 0.3 mg/kg nicotine (three times/day for 14 days) (16). A number of factors might contribute to this observed variability, including the exact dosing, daily frequency, time span of administration, and delivery method of nicotine. Furthermore, as individual studies have each so far generally examined a single opioid peptide, there is currently little reliable information about peptide co-regulation, even for these well studied opioid peptides. In addition to these opioid peptides, the DS expresses peptides from other peptide families, which are also potential targets under the regulation of chronic nicotine treatment. So far, however, there is no information available about changes of these non-opioid peptides during chronic nicotine administration.In this study, our aim was to use a neuropeptidomics approach (17) to provide a comprehensive characterization of dorsal striatal neuropeptides after long term nicotine chronic treatment in adult rats using oral administration. The main advantage of this approach is that it allows the simultaneous monitoring of many peptides from the same brain tissue derived from a single drug protocol. We used a combination of a robust sample preparation method (18), high accuracy LC-MS analysis (19, 20), and the use of multiple synthetic internal standards (21) to compare peptide levels in the DS between chronic nicotine and control animals. Our peptidome analysis determined 14 peptides exhibiting significant changes following chronic nicotine administration. Among these peptides were members of the opioid family that had previously been associated with nicotine dependence, as well as a number of newly identified peptides, including members of the secretogranin, cholecystokinin, and somatostatin families. This greatly expands the present scope of peptide involvement in drug dependence in the dorsal striatum.     

Effect of decomposing post-fire coarse woody debris on soil fertility and nutrient availability in a Mediterranean ecosystem

Post-fire coarse woody debris can represent a valuable nutrient reservoir for a regenerating ecosystem, helping to prevent soil fertility losses after a wildfire. However, there is scarce information on its effect on soil nutrient cycling and availability. We established three study sites along an altitudinal gradient in a burnt pine forest (SE Spain). At each site we determined: (1) decomposition rates and nutrient dynamics in charred logs left on the ground, 2 and 4 years after the fire, and (2) available nutrients in the soil and in the microbial fraction below charred logs and in bare soil areas. Despite the relatively slow decay rates in this Mediterranean climate (ca. 10 % of dry weight lost after 4 years), N and P were progressively released by logs, accounting for ca. 40 and 65 % of the initial content respectively after 4 years. This implies that the total aboveground biomass of the burnt forest released around 20 kg ha^?1 of N and 2 kg ha^?1 of P during this period. The presence of post fire coarse woody debris consistently increased soil organic matter by around 18 %, total C and N by 42 and 26 %, respectively, dissolved organic C and N by 47 %, available inorganic P by 68 %, and microbial biomass and nitrogen by some 36 and 48 %, respectively. By contrast, soil bulk density decreased by ca. 18 % under logs compared to bare areas. Thus, the fire-killed wood was useful in the recovery of soil fertility and nutrient availability. Leaving the post-fire woody debris on site can enhance the biogeochemical sustainability, microbiological processes and soil ecological functioning. The detrimental effect of post-fire salvage logging on soil fertility should be therefore considered when making management decisions.     

Dose-dependent effect of melatonin on postwarming development of vitrified ovine embryos

After cryopreservation, embryos become sensitive to the oxidative stress, resulting in lipid peroxidation, membrane injury, and structural destruction. The present study aimed to assess the effect of increasing concentration of melatonin during postwarming culture on embryo's ability to restore its functions after cryopreservation. In vitro–produced blastocysts were vitrified, warmed, and cultured in vitro in TCM 199 with 5 different supplementations: control (CTR): 10% fetal calf serum; bovine serum albumin (BSA): 0.04% (wt/vol) BSA; and MEL⁻³, MEL⁻⁶, MEL⁻⁹: BSA plus melatonin 10⁻³, 10⁻⁶, and 10⁻⁹ M. The medium with the highest melatonin concentration had the highest trolox equivalent antioxidant capacity, whose values were comparable with those determined in plasma sampled from adult ewes (8.7 ± 2.4 mM). The other media had lower trolox equivalent antioxidant capacity values (P < 0.01), below the range of the plasma. At the same time, embryos cultured with the highest melatonin concentration reported a lower in vitro viability, as evaluated by lower re-expansion and hatching rates, and lower total cell number compared with the other groups (P < 0.05). Their metabolic status was also affected, as evidenced by higher oxidative and apoptotic index and lower ATP concentration. The beneficial effects of melatonin on embryo development during postwarming culture were observed only at low concentration (10⁻⁹ M). These results suggest that melatonin at high concentration may exert some degree of toxic activity on pre-implantation embryos. Thus, the dose at which the embryos are exposed is pivotal to obtain the desiderate effect.     

Incidence and Predictors of Multimorbidity in the Elderly: A Population-Based Longitudinal Study

Background

We aimed to calculate 3-year incidence of multimorbidity, defined as the development of two or more chronic diseases in a population of older people free from multimorbidity at baseline. Secondly, we aimed to identify predictors of incident multimorbidity amongst life-style related indicators, medical conditions and biomarkers.

Methods

Data were gathered from 418 participants in the first follow up of the Kungsholmen Project (Stockholm, Sweden, 1991–1993, 78+ years old) who were not affected by multimorbidity (149 had none disease and 269 one disease), including a social interview, a neuropsychological battery and a medical examination.

Results

After 3 years, 33.6% of participants who were without disease and 66.4% of those with one disease at baseline, developed multimorbidity: the incidence rate was 12.6 per 100 person-years (95% CI: 9.2–16.7) and 32.9 per 100 person-years (95% CI: 28.1–38.3), respectively. After adjustments, worse cognitive function (OR, 95% CI, for 1 point lower Mini-Mental State Examination: 1.22, 1.00–1.48) was associated with increased risk of multimorbidity among subjects with no disease at baseline. Higher age was the only predictor of multimorbidity in persons with one disease at baseline.

Conclusions

Multimorbidity has a high incidence at old age. Mental health-related symptoms are likely predictors of multimorbidity, suggesting a strong impact of mental disorders on the health of older people.     

Mechanical and In Vitro Biological Performance of Graphene Nanoplatelets Reinforced Calcium Silicate Composite

Calcium silicate (CaSiO₃, CS) ceramic composites reinforced with graphene nanoplatelets (GNP) were prepared using hot isostatic pressing (HIP) at 1150°C. Quantitative microstructural analysis suggests that GNP play a role in grain size and is responsible for the improved densification. Raman spectroscopy and scanning electron microscopy showed that GNP survived the harsh processing conditions of the selected HIP processing parameters. The uniform distribution of 1 wt.% GNP in the CS matrix, high densification and fine CS grain size help to improve the fracture toughness by ∼130%, hardness by ∼30% and brittleness index by ∼40% as compared to the CS matrix without GNP. The toughening mechanisms, such as crack bridging, pull-out, branching and deflection induced by GNP are observed and discussed. The GNP/CS composites exhibit good apatite-forming ability in the simulated body fluid (SBF). Our results indicate that the addition of GNP decreased pH value in SBF. Effect of addition of GNP on early adhesion and proliferation of human osteoblast cells (hFOB) was measured in vitro. The GNP/CS composites showed good biocompatibility and promoted cell viability and cell proliferation. The results indicated that the cell viability and proliferation are affected by time and concentration of GNP in the CS matrix.     

Monomeric G-proteins as signal transducers in airway physiology and pathophysiology

Monomeric G-proteins, also referred to as small GTPases, function as biological hubs being activated by extracellular stimuli and regulate downstream signalling events, which result in different cellular responses. The importance of these mechanisms is mirrored by the fact that several pathological conditions, including allergic asthma, are associated with derailed GTPases signalling. For this reason attention has been focused on the role of monomeric G-proteins and their effectors in airway (patho)physiology. In this article we review our current knowledge on the regulation and functions of Ras and Rho GTPase signalling under physiological and pathophysiological conditions in the pulmonary system. Based on recent findings concerning novel regulatory proteins for Ras family members, we further discuss potential future directions for therapeutical interventions in asthma.     

Sex Ratios in a Socially Parasitic Bee and Implications for Host-Parasite Interactions

Obligate social parasites of Hymenoptera, known as inquilines, have received enormous attention due to the elaborate adaptations they exhibit for exploiting their hosts, and because they have frequently been used to infer sympatric speciation. Their population biology can be difficult to infer as they are both rare and difficult to extract from host nests. Sex allocation has been studied for very few inquilines of social Hymenoptera. Here we report sex ratio patterns in the allodapine bee Inquilina schwarzi, which is an obligate social parasite of another allodapine, Exoneura robusta. We show that the sex ratio of this inquiline varies with its brood number, it is female-biased in the smallest broods, but becomes more even in larger broods, where the population-wide sex ratio is close to parity. We argue that this pattern of bias is consistent with local resource competition, where inquiline females compete to inherit their natal colony. We also argue that extremely female-biased sex ratios of the host species, combined with overall sex ratio parity in the parasite, may help ameliorate disparity in effective population sizes between these two species which are locked in an evolutionary arms race.     

The genetic mosaic suggests a new role for hitchhiking in ecological speciation

Early in ecological speciation, the genomically localized effects of divergent selection cause heterogeneity among loci in divergence between incipient species. We call this pattern of genomic variability in divergence the 'genetic mosaic of speciation'. Previous studies have used F(ST) outliers as a way to identify divergently selected genomic regions, but the nature of the relationship between outlier loci and quantitative trait loci (QTL) involved in reproductive isolation has not yet been quantified. Here, we show that F(ST) outliers between a pair of incipient species are significantly clustered around QTL for traits that cause ecologically based reproductive isolation. Around these key QTL, extensive 'divergence hitchhiking' occurs because reduced inter-race mating and negative selection decrease the opportunity for recombination between chromosomes bearing different locally adapted QTL alleles. Divergence hitchhiking is likely to greatly increase the opportunity for speciation in populations that are sympatric, regardless of whether initial divergence was sympatric or allopatric. Early in ecological speciation, analyses of population structure, gene flow or phylogeography based on different random or arbitrarily chosen neutral markers should be expected to conflict--only markers in divergently selected genomic regions will reveal the evolutionary history of adaptive divergence and ecologically based reproductive isolation. Species retain mosaic genomes for a very long time, and gene exchange in hybrid zones can vary dramatically among loci. However, in hybridizing species, the genomic regions that affect ecologically based reproductive isolation are difficult to distinguish from regions that have diverged for other reasons.     

Ecotypes of an ecologically dominant prairie grass (Andropogon gerardii) exhibit genetic divergence across the U.S. Midwest grasslands' environmental gradient

Big bluestem (Andropogon gerardii) is an ecologically dominant grass with wide distribution across the environmental gradient of U.S. Midwest grasslands. This system offers an ideal natural laboratory to study population divergence and adaptation in spatially varying climates. Objectives were to: (i) characterize neutral genetic diversity and structure within and among three regional ecotypes derived from 11 prairies across the U.S. Midwest environmental gradient, (ii) distinguish between the relative roles of isolation by distance (IBD) vs. isolation by environment (IBE) on ecotype divergence, (iii) identify outlier loci under selection and (iv) assess the association between outlier loci and climate. Using two primer sets, we genotyped 378 plants at 384 polymorphic AFLP loci across regional ecotypes from central and eastern Kansas and Illinois. Neighbour‐joining tree and PCoA revealed strong genetic differentiation between Kansas and Illinois ecotypes, which was better explained by IBE than IBD. We found high genetic variability within prairies (80%) and even fragmented Illinois prairies, surprisingly, contained high within‐prairie genetic diversity (92%). Using Bayenv 2, 14 top‐ranked outlier loci among ecotypes were associated with temperature and precipitation variables. Six of seven BayeScan F_ST outliers were in common with Bayenv 2 outliers. High genetic diversity may enable big bluestem populations to better withstand changing climates; however, population divergence supports the use of local ecotypes in grassland restoration. Knowledge of genetic variation in this ecological dominant and other grassland species will be critical to understanding grassland response and restoration challenges in the face of a changing climate.