Phylogeographical pattern of Euplotes nobilii,a protist ciliate with a bipolar biogeographical distribution

Nuclear (18S and ITS) and mitochondrial (16S) ribosomal RNA gene sequences were determined from genetically distinct wild‐type strains of Antarctic (nine strains), Fuegian (four strains), Greenland (nine strains) and Svalbard (three strains) populations of the marine ciliate, Euplotes nobilii, and analysed for their nucleotide polymorphisms. A close genetic homogeneity was found within and between the Antarctic and Fuegian populations, while more significant levels of genetic differentiation were detected within and between the two Arctic populations, as well as between these populations and the Antarctic/Fuegian ones. The phylogeographical pattern that was derived from these data indicates that gene flow is not limited among Arctic populations; it equally connects the Arctic and Antarctic populations either directly, or through the Fuegian population. This indication reinforces previous evidence from laboratory assays of mating interactions between some of the strains analysed in this work that Southern and Northern polar populations of E. nobilii belong to a unique, panmictic population that substantially share the same gene pool.     

Association of small ankyrin 1 with the sarcoplasmic reticulum

Small ankyrin 1, or sAnk1, is a small, alternatively spliced product of the erythroid ankyrin gene, ANK1, that is expressed in striated muscle and concentrated in the network sarcoplasmic reticulum (SR) surrounding the Z disks and M lines. We have characterized sAnk1 in muscle homogenates and SR vesicles, and have identified the region that targets it to the network SR. Selective extractions and partitioning into Triton X-114 show that sAnk1 behaves like the SR Ca-ATPase and so is an integral protein of the SR membrane. Mild proteolytic treatment of isolated SR vesicles indicates that sAnk1 is oriented with its hydrophilic, C-terminal sequence exposed to the solution, which is equivalent to the cytoplasmic face of the SR membrane in situ. SDS-PAGE in non-reducing gels suggests that sAnk1 is present as dimers and larger oligomers in the native SR. These results suggest that sAnk1 is oligomeric and oriented with its C-terminus exposed to the cytoplasm, where it may interact with proteins of the contractile apparatus. The N-terminal 29 amino acid hydrophobic sequence of sAnk1, which is predicted to span the SR membrane, is sufficient to target proteins to and anchor them in internal membranes of HEK 293 cells. It also targets reporter proteins to the network SR of skeletal myofibers and is thus the first example of a sequence that targets proteins to a particular compartment of the SR.     

Maternal postnatal high-fat diet,rather than gestational diet,affects morphology and mTOR pathway in skeletal muscle of weaning rat

The positive regulation of insulin pathway in skeletal muscle results in increased activity of the mammalian target of rapamycin (mTOR), a positive effector of mRNA translation rate and protein synthesis. Studies that assess the activity of this protein in response to chronic high-fat diet (HFD) are scarce and controversial, and to date, there are no studies evaluating the mTOR pathway in infants exposed to gestational and postgestational HFD. This study investigated the effect of maternal HFD on skeletal muscle morphology and on phosphorylation of proteins that comprise the intracellular mTOR signaling pathway in soleus muscle of offspring at weaning. For this purpose, 10 days prior to conception, 39 female Wistar rats were randomly assigned to either control diet (CTL) or HFD. Later, rats were distributed into four groups according to gestational and postpregnancy diet: CTL/CTL (n=10), CTL/HF (n=11), HF/HF (n=10) and HF/CTL (n=8). After 21 days of lactation, pups were killed, and blood samples and soleus and gastrocnemius skeletal muscle were collected for analysis. We observed an influence of maternal postgestational diet, rather than gestational diet, in promoting an obese phenotype, characterized by body fat accumulation, insulin resistance and high serum leptin, glucose, triglycerides and cholesterol levels (P<.05). We have also detected alterations on skeletal muscle morphology — with reduced myofiber density — and impairment on S6 kinase 1 and 4E binding protein-1 phosphorylation (P<.05). These results emphasize the importance of maternal diet during lactation on muscle morphology and on physiological adaptations of infant rats.     

Effect of forced aeration on citric acid production by Aspergillus sp. mutants in SSF

Citric acid (CA) is one of the most important products of fermentation in the world. A great variety of agro-industrial residues can be used in solid state fermentation. Aspergillus niger parental strain (CCT 7716) and two strains obtained by mutagenesis (CCT 7717 and CCT 7718) were evaluated in Erlenmeyer flasks and glass columns using citric pulp (CP) as substrate/support, sugarcane molasses and methanol. Best results using glass columns (forced aeration) were found in the fourth day of fermentation: 278.4, 294.9 and 261.1 g CA/kg of dry CP with CCT 7716, CCT 7718 and CCT 7717, respectively. In Erlenmeyer flasks (aeration by diffusion) CA reached 410.7, 446.8 and 492.7 g CA/kg of dry CP with CCT 7716, CCT 7718 and CCT 7717, respectively. The aeration by diffusion improved CA production by the three strains. A data acquisition system specially developed for biotechnological processes analysis was used to perform the respirometric parameters measurement.     

Acute creatine administration improves mitochondrial membrane potential and protects against pentylenetetrazol-induced seizures

A growing body of evidence indicates that creatine (Cr) exerts beneficial effects on a variety of pathologies where energy metabolism and oxidative stress play an etiological role. However, the benefits of Cr treatment for epileptics are still shrouded in controversy. In the present study, we found that acute Cr treatment (300 mg/kg, p.o.) prevented the increase in electroencephalographic wave amplitude typically elicited by PTZ (30, 45 or 60 mg/kg, i.p.). Cr treatment also increased the latency periods of first myoclonic jerks, lengthened the latency periods of the generalized tonic–clonic seizures and reduced the time spent in the generalized tonic–clonic seizures induced by PTZ (60 mg/kg). Administration of PTZ (all doses) decreased Na⁺, K⁺-ATPase activity as well as adenosine triphosphate (ATP) and adenosine diphosphate levels in the cerebral cortex, but Cr treatment prevented these effects. Cr administration also prevented increases in xanthine oxidase activity, adenosine monophosphate levels, adenosine levels, inosine levels and uric acid levels that normally occur after PTZ treatment (60 mg/kg, i.p.). We also showed that Cr treatment increased the total Cr (Cr + PCr) content, creatine kinase activity and the mitochondrial membrane potential (ΔΨ) in the cerebral cortex. In addition, Cr prevented PTZ-induced mitochondrial dysfunction characterized by decreasing ΔΨ, increasing thiobarbituric acid-reactive substance levels and increasing protein carbonylation. These experimental findings reinforce the idea that mitochondrial dysfunction plays a critical role in models of epileptic seizures and suggest that buffering brain energy levels through Cr treatment may be a promising therapeutic approach for the treatment of this neurological disease.     

Adaptive genetic diversity of trees for forest conservation in a future climate: a case study on Norway spruce in Austria

Genetic resources of forest trees are considered as a key factor for the persistence of forest ecosystems because the ability of tree species to survive under changing climate depends strongly on their intraspecific variation in climate response. Therefore, utilizing available genetic variation in climate response and planting alternative provenances suitable for future climatic conditions is considered as an important adaptation measure for forestry. On the other hand, the distribution of adaptive genetic diversity of many tree species is still unknown and the predicted shift of ecological zones and species’ distribution may threaten forest genetic resources that are important for adaptation. Here, we use Norway spruce in Austria as a case study to demonstrate the genetic variation in climate response and to analyse the existing network of genetic conservation units for its effectiveness to safeguard the hotspots of adaptive and neutral genetic diversity of this species. An analysis of the climate response of 480 provenances, clustered into 9 groups of climatically similar provenances, revealed high variation among provenance groups. The most productive and promising provenance clusters for future climates originate from three regions that today depict the warmest and driest areas of the natural spruce distribution in Austria. Gap analysis of the Austrian genetic conservation units in the EUFGIS Portal suggests adequate coverage of the genetic hotspots in southern parts of Austria, but not in eastern and northern Austria. Therefore conservation measures and sustainable utilization of the valuable genetic resources in these regions need to be expanded to cover their high adaptive genetic variation and local adaptation to a warmer climate. The study shows that current conservation efforts need to be evaluated for their effectiveness to protect genetic resources that are important for the survival of trees in a future climate.     

Comparison of screening methods for high-throughput determination of oil yields in micro-algal biofuel strains

The phenotypic and phylogenetic diversity of micro-algae capable of accumulating triacylglycerols provides a challenge for the accurate determination of biotechnological potential. High-yielding strains are needed to improve economic viability and their compositional information is required for optimizing biodiesel properties. To facilitate a high-throughput screening programme, a very rapid direct-derivatization procedure capable of extracting lyophilized material for GC analysis was compared with a scaled-down Folch-based method. This was carried out on ten micro-algal strains from 6 phyla where the more rapid direct-derivatization approach was found to provide a more reliable measure of yield. The modified Folch-based procedure was found to substantially underestimate oil yield in one Chlorella species (P?<?0.01). In terms of fatty acid composition however, the Folch procedure proved to be slightly better in recovering polyunsaturated fatty acids, in six out of the ten strains. Therefore, direct-derivatization is recommended for rapid determination of yields in screening approaches but can provide slightly less compositional accuracy than solvent-based extraction methods.     

The SH2 Domain Interaction Landscape

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Highlights? The recognition specificity of 70 SH2 domains is probed ? Recognition specificity diverges faster than sequence ? PepspotDB is a database of protein interactions mediated by SH2 domains