Does nitrate deposition following astrophysical ionizing radiation events pose an additional threat to amphibians?

It is known that amphibians are especially susceptible to the combination of heightened UVB radiation and increased nitrate concentrations. Various astrophysical events have been suggested as sources of ionizing radiation that could pose a threat to life on Earth, through destruction of the ozone layer and subsequent increase in UVB, followed by deposition of nitrate. In this study, we investigate whether the nitrate deposition following an ionizing event is sufficiently large to cause an additional stress beyond that of the heightened UVB previously considered. We have converted predicted nitrate depositions to concentration values, utilizing data from the New York State Department of Environmental Conservation Acid Rain Monitoring Network web site. Our results show that the increase in nitrate concentration in bodies of water following the most intense ionization event likely in the last billion years would not be sufficient to cause a serious additional stress on amphibian populations and may actually provide some benefit by acting as fertilizer.Comment: This version is a longer, more detailed draft of an article submitted to the journal Astrobiolog

Effects of Estrogens on Adipokines and Glucose Homeostasis in Female Aromatase Knockout Mice

The maintenance of glucose homeostasis within the body is crucial for constant and precise performance of energy balance and is sustained by a number of peripheral organs. Estrogens are known to play a role in the maintenance of glucose homeostasis. Aromatase knockout (ArKO) mice are estrogen-deficient and display symptoms of dysregulated glucose metabolism. We aim to investigate the effects of estrogen ablation and exogenous estrogen administration on glucose homeostasis regulation. Six month-old female wildtype, ArKO, and 17β-estradiol (E2) treated ArKO mice were subjected to whole body tolerance tests, serum examination of estrogen, glucose and insulin, ex-vivo muscle glucose uptake, and insulin signaling pathway analyses. Female ArKO mice display increased body weight, gonadal (omental) adiposity, hyperinsulinemia, and liver triglycerides, which were ameliorated upon estrogen treatment. Tolerance tests revealed that estrogen-deficient ArKO mice were pyruvate intolerant hence reflecting dysregulated hepatic gluconeogenesis. Analyses of skeletal muscle, liver, and adipose tissues supported a hepatic-based glucose dysregulation, with a down-regulation of Akt phosphorylation (a key insulin signaling pathway molecule) in the ArKO liver, which was improved with E2 treatment. Concurrently, estrogen treatment lowered ArKO serum leptin and adiponectin levels and increased inflammatory adipokines such as tumour necrosis factor alpha (TNFα) and interleukin 6 (IL6). Furthermore, estrogen deficiency resulted in the infiltration of CD45 macrophages into gonadal adipose tissues, which cannot be reversed by E2 treatment. This study describes the effects of estrogens on glucose homeostasis in female ArKO mice and highlights a primary phenotype of hepatic glucose dysregulation and a parallel estrogen modified adipokine profile. © 2015 Van Sinderen et al

Internal and external factors affecting photosynthetic pigment composition in plants: A meta-analytical approach

Photosynthetic pigment composition has been a major study target in plant ecophysiology during the last three decades. Although more than 2000 papers have been published, a comprehensive evaluation of the responses of photosynthetic pigment composition to environmental conditions is not yet available. After an extensive survey, we compiled data from 525 papers including 809 species (subkingdom Viridiplantae) in which pigment composition was described. A meta-analysis was then conducted to assess the ranges of photosynthetic pigment content. Calculated frequency distributions of pigments were compared with those expected from the theoretical pigment composition. Responses to environmental factors were also analysed. The results revealed that lutein and xanthophyll cycle pigments (VAZ) were highly responsive to the environment, emphasizing the high phenotypic plasticity of VAZ, whereas neoxanthin was very stable. The present meta-analysis supports the existence of relatively narrow limits for pigment ratios and also supports the presence of a pool of free 'unbound' VAZ. Results from this study provide highly reliable ranges of photosynthetic pigment contents as a framework for future research on plant pigments.The authors acknowledge the support of research grants BFU2010-15021, UPV/EHU-GV IT-624-13, the JAE-Doc-2011-046 fellow from the Spanish National Research Council (CSIC),received by R.E., and the Marie Curie IEF grant (328370MELISSA) from the European FP7-PEOPLE, receive d byB.F.M.Peer Reviewe

Serum glucose, insulin and HOMA-IR levels.

<p>(<b>a</b>) Fasted and 20 min post glucose infused serum glucose (<b>b</b>) Fasted serum insulin and (<b>c</b>) HOMA-IR (fasted serum glucose (mmol/l) × fasted serum insulin (µU/l)/22.5) from 3 and 6 month-old fasted male wildtype (WT) and aromatase knockout (KO) and KO treated with 2.5 µg/day estrogen (KOE). Expression data from samples (n =  shown on corresponding bar) per genotype are shown, and are presented from replicate analysis as the mean ± SD. <i>*p&lt;0.05</i> versus WT mice. ^#<i>p&lt;0.05</i> versus KO.</p

Liver Triglyceride levels.

<p>Liver triglyceride assay were performed on 3 and 6 month-old fasted male wildtype (WT), aromatase knockout (KO) and 17β-estradiol-treated KO (KOE) mice. Expression data from 7–8 samples per genotype are shown following and presented from replicate analysis as the mean ± SD. <i>**p&lt;0.01</i>, versus expression in age-matched WT samples and <i>^###p&lt;0.001</i> versus age-matched KO samples and ∧∧p&lt;0.01, ∧∧∧p&lt;0.001, versus 3mth old KO samples.</p

Body and adipose weights, adipokines levels.

<p>Body and gonadal adipose tissue weights in grams (g) and serum leptin in micrograms per milliliter (µg/ml) and adiponectin levels in nanograms per milliliter (ng/ml) of 3 and 6 month-old male wild type (WT), aromatase knockout (KO) and 2.5 µg/day 17β-estradiol-treated KO (KOE). Data are expressed as mean ± SD; n = 7–8 per group,<i>*p&lt;0.05 and **p&lt;0.01</i> versus WT mice. ^#<i>p&lt;0.05</i>, ^##<i>p&lt;0.01</i>^###<i>p&lt;0.001</i> versus KO.</p

Real-time PCR primers.

<p>List of primer sequences (and expected amplicon sizes) used for Real-Time PCR.</p

Real-time PCR analysis of gluconeogenesis mRNA expression in the liver.

<p>Real-time-PCR analyses of G6Pase, PEPCK, IRS1, IRS2 and GSK3β mRNA expression were performed on cDNA derived from total RNA prepared from fasted liver tissue of (a) 3 and (b) 6 month-old male wildtype (WT, n = 8), aromatase knockout (KO, n = 8) and 2.5 µg/day 17β-estradiol-treated KO (KOE, n = 7) mice. Expression data from 7–8 samples per genotype are shown following normalization for cyclophilin mRNA expression, and presented from replicate analysis as the mean ± SD. <i>*p&lt;0.05,**p&lt;0.01</i> and <i>***p&lt;0.001</i> versus expression in age-matched WT samples and <i>^##p&lt;0.01, ^###p&lt;0.05</i> versus KO samples.</p

Serum adipokine and gonadal adipose tissue adipokine transcript levels.

<p>Serum adipokine analyses of <b>(a)</b> leptin, <b>(b)</b> Adiponectin and <b>(c)</b> TNFα, IL6 and MCP1 concentrations were performed on serum from six month-old female wildtype (WT), Aromatase knockout (KO) and 2.5μg/day 17β-estradiol-treated KO (KOE) mice. Data are presented as mean ± SD (n = 6/group). *<i>p< 0</i>.<i>05</i>, **<i>p<0</i>.<i>01</i>, versus expression in age-matched <i>WT</i> samples and #<i>#p<0</i>.<i>01</i> verses KO samples. Real-time-PCR analyses of <b>(d</b>) Leptin, <b>(e)</b> Adiponectin, <b>(f)</b> TNFα, IL6 and MCP1 gene expression were performed on cDNA derived from total RNA prepared from gonadal adipose tissue of six month-old female wildtype (WT), Aromatase knockout (KO) and 2.5μg/day 17β-estradiol-treated KO (KOE) mice. Data are presented as mean ± SD (n = 7/group). following normalization to cyclophilin *<i>p<0</i>.<i>05</i>, **<i>p<0</i>.<i>01</i>, ***<i>p<0</i>.<i>001</i> versus expression in age-matched WT samples and ^##<i>p<0</i>.<i>01 and</i>^###<i>p<0</i>.<i>001</i> verses KO samples.</p

Real-time PCR analysis of mRNA lipid profile in the liver.

<p>Real-time-PCR analyses of Fasn, ACCα and Scd-1 mRNA expression were performed on cDNA derived from total RNA prepared from fasted liver tissue of (a) 3 and (b) 6 month-old male wildtype (WT, n = 8), aromatase knockout (KO, n = 8) and 2.5 µg/day 17β-estradiol-treated KO (KOE, n = 7) mice. Expression data from 7–8 samples per genotype are shown following normalization for cyclophilin mRNA expression, and presented from replicate analysis as the mean ± SD. <i>*p&lt;0.05, **p&lt;0.01 and **p&lt;0.001</i>, versus expression in age-matched WT samples and <i>^##p&lt;0.01, ^###p&lt;0.001</i> versus KO samples.</p