Dose dependent effects of ghrelin on pentylenetetrazole-induced oxidative stress in a rat seizure model

It has been suggested that free oxygen radicals play a role in the genesis of epilepsy and in post-seizure neuronal death. The aim of this study was to investigate the dose dependent effect of ghrelin on pentylenetetrazole (PTZ)-induced oxidative stress in a rat seizure model. For this purpose, the ghrelin groups were treated with intraperitoneal injections of ghrelin at doses of 20, 40, 60 and 80 microg/kg before the PTZ injection. Superoxide dismutase (SOD) and catalase (CAT) activities, and reduced glutathione (GSH) and thiobarbituric acid-reactive substance (TBARS) levels were measured in erythrocytes, liver and brain tissue. TBARS, the indicator of lipid peroxidation, was significantly increased in erythrocytes, liver and brain tissue, while antioxidant enzyme activities and glutathione levels were significantly decreased in PTZ injected rats. Ghrelin pretreatment prevented lipid peroxidation and the reduction in antioxidant enzyme activities and GSH levels against PTZ-induced oxidative stress in a dose dependent manner. The present data indicates that PTZ at a convulsive dose induces an oxidative stress response by depleting the antioxidant defense systems and increasing lipid peroxidation in the erythrocytes, liver and brain of rats. Ghrelin pretreatment diminished oxidative stress and prevented the decrease in antioxidant enzyme activities, and thus may reduce neuronal death in the brain during seizures. However, further studies are needed in order to confirm our hypothesis.     

Mutation and selection processes regulating short tandem repeats give rise to genetic and phenotypic diversity across species

Short tandem repeats (STRs) are units of 1–6 bp that repeat in a tandem fashion in DNA. Along with single nucleotide polymorphisms and large structural variations, they are among the major genomic variants underlying genetic, and likely phenotypic, divergence. STRs experience mutation rates that are orders of magnitude higher than other well-studied genotypic variants. Frequent copy number changes result in a wide range of alleles, and provide unique opportunities for modulating complex phenotypes through variation in repeat length. While classical studies have identified key roles of individual STR loci, the advent of improved sequencing technology, high-quality genome assemblies for diverse species, and bioinformatics methods for genome-wide STR analysis now enable more systematic study of STR variation across wide evolutionary ranges. In this review, we explore mutation and selection processes that affect STR copy number evolution, and how these processes give rise to varying STR patterns both within and across species. Finally, we review recent examples of functional and adaptive changes linked to STRs.     

Ribosomal RNA and protein mutants resistant to spectinomycin.

We have compared the influence of spectinomycin (Spc) on individual partial reactions during the elongation phase of translation in vitro by wild-type and mutant ribosomes. The data show that the antibiotic specifically inhibits the elongation factor G (EF-G) cycle supported by wild-type ribosomes. In addition, we have reproduced the in vivo Spc resistant phenotype of relevant ribosome mutants in our in vitro translation system. In particular, three mutants with alterations at position 1192 in 16S rRNA as well as an rpsE mutant with an alteration of protein S5 were analysed. All of these ribosomal mutants confer a degree of Spc resistance for the EF-G cycle in vitro that is correlated with the degree of growth rate resistance to the antibiotic in culture.     

Co-production of tannase and pectinase by free and immobilized cells of the yeast Rhodotorula glutinis MP-10 isolated from tannin-rich persimmon (Diospyros kaki L.) fruits

Hyper tannase and pectinase-producing yeast Rhodotorula glutinis MP-10 was isolated from persimmon (Diospyros kaki L.) fruits. The main pectinase activity of yeast was exo-polygalacturonase. No pectin methyl esterase and too low pectin lyase activities were detected for this yeast. The maximum exo-activities of tannase and polygalacturonase were determined as 15.2 and 26.9 U/mL for free cells and 19.8 and 28.6 U/mL for immobilized cells, respectively. Immobilized cells could be reused in 13 successive reaction cycles without any loss in the maximum tannase and polygalacturonase activities. Besides, too little decreases in activities of these enzymes were recorded between 14 and 18 cycles. At the end of 18 successive reaction cycles, total 503.1 U/mL of polygalacturonase and 349.6 U/mL of tannase could be produced using the same immobilized cells. This is the first report on the use of free and/or immobilized cells of a microorganism for the co-production of tannase and pectinase.     

Ecoregion-Based Conservation Planning in the Mediterranean: Dealing with Large-Scale Heterogeneity

Spatial priorities for the conservation of three key Mediterranean habitats, i.e. seagrass Posidonia oceanica meadows, coralligenous formations, and marine caves, were determined through a systematic planning approach. Available information on the distribution of these habitats across the entire Mediterranean Sea was compiled to produce basin-scale distribution maps. Conservation targets for each habitat type were set according to European Union guidelines. Surrogates were used to estimate the spatial variation of opportunity cost for commercial, non-commercial fishing, and aquaculture. Marxan conservation planning software was used to evaluate the comparative utility of two planning scenarios: (a) a whole-basin scenario, referring to selection of priority areas across the whole Mediterranean Sea, and (b) an ecoregional scenario, in which priority areas were selected within eight predefined ecoregions. Although both scenarios required approximately the same total area to be protected in order to achieve conservation targets, the opportunity cost differed between them. The whole-basin scenario yielded a lower opportunity cost, but the Alboran Sea ecoregion was not represented and priority areas were predominantly located in the Ionian, Aegean, and Adriatic Seas. In comparison, the ecoregional scenario resulted in a higher representation of ecoregions and a more even distribution of priority areas, albeit with a higher opportunity cost. We suggest that planning at the ecoregional level ensures better representativeness of the selected conservation features and adequate protection of species, functional, and genetic diversity across the basin. While there are several initiatives that identify priority areas in the Mediterranean Sea, our approach is novel as it combines three issues: (a) it is based on the distribution of habitats and not species, which was rarely the case in previous efforts, (b) it considers spatial variability of cost throughout this socioeconomically heterogeneous basin, and (c) it adopts ecoregions as the most appropriate level for large-scale planning.     

Phylogeography of the large Myotis bats (Chiroptera: Vespertilionidae) in Europe,Asia Minor,and Transcaucasia

The large Myotis complex in continental Europe, Asia Minor, and Transcaucasia comprises two sibling bat species, the greater mouse‐eared bat, Myotis myotis, and the lesser mouse‐eared bat, Myotis blythii, also referred to as Myotis oxygnathus. Here, we investigate the phylogeography of these bats using two mitochondrial markers: the second hypervariable domain of the control region (HVII) and a fragment of the cytochrome b gene (cyt b). The HVII haplotypes formed six distinct haplogroups associated with different geographical regions. Most of the European HVII haplotypes were exclusive to M. myotis, whereas the majority of HVII haplotypes found in Asia Minor were exclusive to M. blythii/M. oxygnathus. The phylogenetic reconstruction based on the concatenated cyt b and HVII fragments recovered two major lineages. The first lineage comprised samples from Europe (western lineage), and the second lineage included samples from Asia Minor, Transcaucasia, Crimea, Western Ukraine, Thrace, the Balkans, and Eastern Europe (eastern lineage). The mitochondrial lineage of M. blythii, reported from Kyrgyzstan, was not present in Asia Minor and Transcaucasia. Therefore, we consider the possibility that the M. blythii/M. oxygnathus found in Europe, Asia Minor, and Transcaucasia are not recent descendants of the Central Asian M. blythii. Instead, we suggest that M. blythii/M. oxygnathus and M. myotis diverged through allopatric speciation in Asia Minor and Europe, and that they are represented by the eastern and western mitochondrial lineages. We also examine an alternative hypothesis: that the large Myotis complex consists of more than two species that diverged independently in Asia Minor and Europe through ecological speciation. © 2012 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, ??, ??–??.     

Selective quantification of viable Escherichia coli bacteria in biosolids by quantitative PCR with propidium monoazide modification

Quantitative differentiation of live cells in biosolids samples, without the use of culturing-based approaches, is highly critical from a public health risk perspective, as recent studies have shown significant regrowth and reactivation of indicator organisms. Persistence of DNA in the environment after cell death in the range of days to weeks limits the application of DNA-based approaches as a measure of live cell density. Using selective nucleic acid intercalating dyes like ethidium monoazide (EMA) and propidium monoazide (PMA) is one of the alternative approaches to detecting and quantifying viable cells by quantitative PCR. These compounds have the ability to penetrate only into dead cells with compromised membrane integrity and intercalate with DNA via their photoinducible azide groups and in turn inhibit DNA amplification during PCRs. PMA has been successfully used in different studies and microorganisms, but it has not been evaluated sufficiently for complex environmental samples such as biosolids. In this study, experiments were performed with Escherichia coli ATCC 25922 as the model organism and the uidA gene as the target sequence using real-time PCR via the absolute quantification method. Experiments with the known quantities of live and dead cell mixtures showed that PMA treatment inhibits PCR amplification from dead cells with over 99% efficiency. The results also indicated that PMA-modified quantitative PCR could be successfully applied to biosolids when the total suspended solids (TSS) concentration is at or below 2,000 mg·liter(-1).     

Antipodean white sharks on a Mediterranean walkabout? Historical dispersal leads to genetic discontinuity and an endangered anomalous population

The provenance of white sharks (Carcharodon carcharias) in the Mediterranean is both a conundrum and an important conservation issue. Considering this species's propensity for natal philopatry, any evidence that the Mediterranean stock has little or no contemporary immigration from the Atlantic would suggest that it is extraordinarily vulnerable. To address this issue we sequenced the mitochondrial control region of four rare Mediterranean white sharks. Unexpectedly, the juvenile sequences were identical although collected at different locations and times, showing little genetic differentiation from Indo-Pacific lineages, but strong separation from geographically closer Atlantic/western Indian Ocean haplotypes. Historical long-distance dispersal (probably a consequence of navigational error during past climatic oscillations) and potential founder effects are invoked to explain the anomalous relationships of this isolated 'sink' population, highlighting the present vulnerability of its nursery grounds.     

Multilocus phylogenetic analysis of true morels (Morchella) reveals high levels of endemics in Turkey relative to other regions of Europe

The present study was conducted to better understand how the phylogenetic diversity of true morels (Morchella) in Turkey compares with species found in other regions of the world. The current research builds on our recently published surveys of 10 Turkish provinces and the northern hemisphere in which DNA sequence data from 247 and 562 collections respectively were analyzed phylogenetically. Herein we report on phylogenetic analyses of 243 additional collections made in spring 2009 and 2010 from eight additional provinces in the Aegean, Black Sea, central Anatolia, eastern Anatolia and Marmara regions of Turkey. Our analysis revealed that five species within the Esculenta clade (yellow morels) and 15 species within the Elata clade (black morels) were present in Turkey. Our preliminary results also indicate that M. anatolica, recently described from a collection in Mu?la province in the Aegean region of Turkey, is a closely related sister of M. rufobrunnea; these two species comprise a separate evolutionary lineage from the Esculenta and Elata clades. Nine species of Morchella currently are known only from Turkey, four species were present in Turkey and other European countries and seven species might have been introduced to Turkey anthropogenically. Three of the putatively exotic species in Turkey appear to be endemic to western North America; they are nested within a clade of fire-adapted morels that dates to the late Oligocene, 25 000 000 y ago. Our results indicate that there are roughly twice as many Morchella species in Turkey compared with the other regions of Europe sampled. Knowledge of Morchella species diversity and their biogeographic distribution are crucial for formulating informed conservation policies directed at preventing species loss and ensuring that annual morel harvests are sustainable and ecologically sound.