Effect of variation of salinity on protein, RNA and DNA contents of liver, muscle and ovary of female singi fish, heteropneustes fossilis (Bloch), at two phases of reproductive cycle

Investigou-se as mudanças causadas nos teores de proteínasje ácidos nucleicos do fígado, músculo, ovários e peso dos orgãos (HSI, GSI) pela variação de salinidade do meio (65, 135 e 225_mOsm, NaCl/litro2 e salinidade zero ou água destilada) em fêmeas nao vitelogenicas (NV) e vitelogênicas (V) do peixe Heteropneustes fossilis (Bloch) às temperaturas de 25ºC e 30ºC, 30 dias após o período de aclimação nos respectivos meios. Obteve-se valores máximos de HSI tanto nos peixes (NV) e (V) quando mantidos em água destilada e valores mínimos quando em solução de 225 mOsm. 0 aumento de temperatura de 25ºC para 30°C causou uma redução nos valores de HSI somente nos peixes (V). Salinidade de 135 e 65-135 mOsm produziu o valor mais alto de GSI nos dois grupos de peixes: (NV) e (V). 0 efeito estimulante da alta temperatura (30°C) no GSI foi encontrado somente nos peixes (NV) em todos os meios salinos. 0 teor hepático de proteínas e RNA foi máximo nos peixes (NV) e (V) mantidos em meios de 65 mOsm de NaCl e mínimo nos de 225 mOsm de salinidade. 0 aumento de temperatura de 25ºC para 30ºC não alterou o teor protéico hepático mas aumentou e diminuiu o teor de RNA nas fases (V) e (NV). 0 teor muscular de proteínas e RNA foram máximos a salinidadgs zero e 65 mOsm e mínimos a 225 mOsm tanto a 25ºC , como 30ºC. A alta temperatura (30°C) aumentou o teor protéico, mas não alterou o teor de RNA. Salinidade de 135 mOsm causou o maior aumento nos teores dg proteínas, RNA e DNA do ovário das fêmeas (NV) a 25°C ou 30ºC. Salinidade zero reduziu bastante o teor desta substância no ovário. No caso do GSI o efeito estimulador da alta temperatura (30°C) no acúmulo de proteínas, RNA e DNA se fez sentir em todas as concentrações salinas do meio. Os peixes (V) apresentaram teor máximo de proteínas ovarianas a salinidade de 135 mOsm e mínimos em água destilada. Os ovários (V) tiveram a taxa mais alta de DNA em 65 e 135 mOsm de salinidade do que a zero ou 225 mOsm. A influência das altas temperaturas não foi sentida nas fêmeas (V). 0 teor de RNA ovariano dos peixes (V) também não se alterou em todas as condições experimentais.

Contrasting patterns of genetic diversity at three different genetic markers in a marine mammal metapopulation

Many studies use genetic markers to explore population structure and variability within species. However, only a minority use more than one type of marker and, despite increasing evidence of a link between heterozygosity and individual fitness, few ask whether diversity correlates with population trajectory. To address these issues, we analyzed data from the Steller’s sea lion, Eumetiopias jubatus, where three stocks are distributed over a vast geographical range and where both genetic samples and detailed demographic data have been collected from many diverse breeding colonies. To previously published mitochondrial DNA(mtDNA) and microsatellite data sets,we have added new data for amplified fragment length polymorphism (AFLP) markers, comprising 238 loci scored in 285 sea lions sampled from 23 natal rookeries. Genotypic diversity was low relative to most vertebrates, with only 37 loci (15.5%) being polymorphic. Moreover, contrasting geographical patterns of genetic diversity were found at the three markers, with Nei’s gene diversity tending to be higher for AFLPs and microsatellites in rookeries of the western and Asian stocks, while the highest mtDNA values were found in the eastern stock. Overall, and despite strongly contrasting demographic histories, after applying phylogenetic correction we found little correlation between genetic diversity and either colony size or demography. In contrast, we were able to show a highly significant positive relationship between AFLP diversity and current population size across a range of pinniped species, even though equivalent analyses did not reveal significant trends for either microsatellites or mtDNA

Genome-wide introgression among distantly related Heliconius butterfly species

Background: Although hybridization is thought to be relatively rare in animals, the raw genetic material introduced via introgression may play an important role in fueling adaptation and adaptive radiation. The butterfly genus Heliconius is an excellent system to study hybridization and introgression but most studies have focused on closely related species such as H. cydno and H. melpomene. Here we characterize genome-wide patterns of introgression between H. besckei, the only species with a red and yellow banded 'postman' wing pattern in the tiger-striped silvaniform clade, and co-mimetic H. melpomene nanna. Results: We find a pronounced signature of putative introgression from H. melpomene into H. besckei in the genomic region upstream of the gene optix, known to control red wing patterning, suggesting adaptive introgression of wing pattern mimicry between these two distantly related species. At least 39 additional genomic regions show signals of introgression as strong or stronger than this mimicry locus. Gene flow has been on-going, with evidence of gene exchange at multiple time points, and bidirectional, moving from the melpomene to the silvaniform clade and vice versa. The history of gene exchange has also been complex, with contributions from multiple silvaniform species in addition to H. besckei. We also detect a signature of ancient introgression of the entire Z chromosome between the silvaniform and melpomene/cydno clades. Conclusions: Our study provides a genome-wide portrait of introgression between distantly related butterfly species. We further propose a comprehensive and efficient workflow for gene flow identification in genomic data sets

Potential utility of natural products as regulators of breast cancer-associated aromatase promoters

Aromatase, the key enzyme in estrogen biosynthesis, converts androstenedione to estrone and testosterone to estradiol. The enzyme is expressed in various tissues such as ovary, placenta, bone, brain, skin, and adipose tissue. Aromatase enzyme is encoded by a single gene CYP 19A1 and its expression is controlled by tissue-specific promoters. Aromatase mRNA is primarily transcribed from promoter I.4 in normal breast tissue and physiological levels of aromatase are found in breast adipose stromal fibroblasts. Under the conditions of breast cancer, as a result of the activation of a distinct set of aromatase promoters (I.3, II, and I.7) aromatase expression is enhanced leading to local overproduction of estrogen that promotes breast cancer. Aromatase is considered as a potential target for endocrine treatment of breast cancer but due to nonspecific reduction of aromatase activity in other tissues, aromatase inhibitors (AIs) are associated with undesirable side effects such as bone loss, and abnormal lipid metabolism. Inhibition of aromatase expression by inactivating breast tumor-specific aromatase promoters can selectively block estrogen production at the tumor site. Although several synthetic chemical compounds and nuclear receptor ligands are known to inhibit the activity of the tumor-specific aromatase promoters, further development of more specific and efficacious drugs without adverse effects is still warranted. Plants are rich in chemopreventive agents that have a great potential to be used in chemotherapy for hormone dependent breast cancer which could serve as a source for natural AIs. In this brief review, we summarize the studies on phytochemicals such as biochanin A, genistein, quercetin, isoliquiritigenin, resveratrol, and grape seed extracts related to their effect on the activation of breast cancer-associated aromatase promoters and discuss their aromatase inhibitory potential to be used as safer chemotherapeutic agents for specific hormone-dependent breast cancer

Fusion cross sections for 6,7Li + 24Mg reactions at energies below and above the barrier

Measurement of fusion cross sections for the 6,7Li + 24Mg reactions by the characteristic gamma-ray method has been done at energies from below to well above the respective Coulomb barriers. The fusion cross sections obtained from these gamma-ray cross sections for the two systems are found to agree well with the total reaction cross sections at low energies. The decrease of fusion cross sections with increase of energy is consistent with the fact that other channels, in particular breakup open up with increase of bombarding energy. This shows that there is neither inhibition nor enhancement of fusion cross sections for these systems at above or below the barrier. The critical angular momenta (lcr) deduced from the fusion cross sections are found to have an energy dependence similar to other Li - induced reactions.Comment: 1 .pdf fil

Drift Removal in Plant Electrical Signals via IIR Filtering Using Wavelet Energy

This is the author accepted manuscript. The final version is available from Elsevier via the DOI in this record.Plant electrical signals often contains low frequency drifts with or without the application of external stimuli. Quantification of the randomness in plant signals in a stimulus-specific way is hindered because the knowledge of vital frequency information in the actual biological response is not known yet. Here we design an optimum Infinite Impulse Response (IIR) filter which removes the low frequency drifts and preserves the frequency spectrum corresponding to the random component of the unstimulated plant signals by bringing the bias due to unknown artifacts and drifts to a minimum. We use energy criteria of wavelet packet transform (WPT) for optimization based tuning of the IIR filter parameters. Such an optimum filter enforces that the energy distribution of the pre-stimulus parts in different experiments are almost overlapped but under different stimuli the distributions of the energy get changed. The reported research may popularize plant signal processing, as a separate field, besides other conventional bioelectrical signal processing paradigms.This work was supported by EU FP7 project PLants Employed As SEnsor Devices (PLEASED), EC grant agreement number 296582

Two closely related ureotelic fish species of the genus Alcolapia express different levels of ammonium transporters in gills

Most fish excrete their nitrogenous waste across the gills as ammonia through the activity of the Rhesus glycoprotein ammonium transporters. In contrast, fish of the subgenus Alcolapia (Oreochromis) are the only vertebrates that survive the extreme conditions of the soda lakes of Natron and Magadi in East Africa and have evolved adaptations to the highly alkaline waters including the ability to excrete their nitrogenous waste as urea. Nevertheless, Alcolapia retain the Rhesus glycoprotein genes in their genomes and using two heterologous expression systems, we demonstrate that Alcolapia Rhbg is capable of moving ammonia. Comparing ammonia and urea excretion from two closely related Alcolapia species from the same aquarium, we found that while Alcolapia grahami remains fully ureotelic after many generations in lab conditions, Alcolapia alcalica excretes some of its nitrogenous waste as ammonia. Using in situ hybridisation, we demonstrate robust, localised gene expression of Rhbg, rhcg1 and rhcg2 in the gill tissue in both A. alcalica embryos and adults, similar to that in other ammoniotelic fish. In contrast, the expression of these genes in A. grahami gills is much lower than in A. alcalica, suggesting the rapid evolution of a molecular mechanism underlying the complete ureotelism of A. grahami

Integrating ecology into macroevolutionary research

On 9 March, over 150 biologists gathered in London for the Centre for Ecology and Evolution spring symposium, ‘Integrating Ecology into Macroevolutionary Research’. The event brought together researchers from London-based institutions alongside others from across the UK, Europe and North America for a day of talks. The meeting highlighted methodological advances and recent analyses of exemplar datasets focusing on the exploration of the role of ecological processes in shaping macroevolutionary patterns

Deep convergence, shared ancestry and evolutionary novelty in the genetic architecture of heliconius mimicry

Convergent evolution can occur through different genetic mechanisms in different species. It is now clear that convergence at the genetic level is also widespread, and can be caused by either (i) parallel genetic evolution, where independently evolved convergent mutations arise in different populations or species, or (ii) collateral evolution in which shared ancestry results from either ancestral polymorphism or introgression among taxa. The adaptive radiation of Heliconius butterflies shows color pattern variation within species, as well as mimetic convergence between species. Using comparisons from across multiple hybrid zones, we use signals of shared ancestry to identify and refine multiple putative regulatory elements in Heliconius melpomene and its comimics, Heliconius elevatus and Heliconius besckei, around three known major color patterning genes: optix, WntA, and cortex. While we find that convergence between H. melpomene and H. elevatus is caused by a complex history of collateral evolution via introgression in the Amazon, convergence between these species in the Guianas appears to have evolved independently. Thus, we find adaptive convergent genetic evolution to be a key driver of regulatory changes that lead to rapid phenotypic changes. Furthermore, we uncover evidence of parallel genetic evolution at some loci around optix and WntA in H. melpomene and its distant comimic Heliconius erato. Ultimately, we show that all three of convergence, conservation, and novelty underlie the modular architecture of Heliconius color pattern mimicry

Major improvements to the Heliconius melpomene genome assembly used to confirm 10 chromosome fusion events in 6 million years of butterfly evolution

The Heliconius butterflies are a widely studied adaptive radiation of 46 species spread across Central and South America, several of which are known to hybridize in the wild. Here, we present a substantially improved assembly of the Heliconius melpomene genome, developed using novel methods that should be applicable to improving other genome assemblies produced using short read sequencing. First, we whole-genome-sequenced a pedigree to produce a linkage map incorporating 99% of the genome. Second, we incorporated haplotype scaffolds extensively to produce a more complete haploid version of the draft genome. Third, we incorporated ~20x coverage of Pacific Biosciences sequencing, and scaffolded the haploid genome using an assembly of this long-read sequence. These improvements result in a genome of 795 scaffolds, 275 Mb in length, with an N50 length of 2.1 Mb, an N50 number of 34, and with 99% of the genome placed, and 84% anchored on chromosomes. We use the new genome assembly to confirm that the Heliconius genome underwent 10 chromosome fusions since the split with its sister genus Eueides, over a period of about 6 million yr