Influence of carbon and nitrogen sources on lipase production by a newly isolated Candida viswanathii strain

Microorganisms can produce lipases with different biochemical characteristics making necessary the screening of new lipase-producing strains for different industrial applications. In this study, 90 microbial strains were screened as potential lipase producers using a sensitive agar plate method with a suitable medium supplemented with Tween 20 and also a liquid culture supplemented with olive oil. The highest cell growth and lipase production for Candida viswanathii were observed in triolein and oleic acid when used as the only pure carbon source. Renewable low-cost triacylglycerols supported the best cell growth, and olive oil was found to be the best inducer for lipase production (19.50 g/L and 58.50 U). The selected conditions for enzyme production were found with yeast extract as nitrogen source and 1.5 % (w/v) olive oil (85.70 U) that resulted in a good cell growth yield (Y_X/S?=?1.234 g/g) and lipase productivity (1.204 U/h) after 72 h of shake-flask cultivation. C. viswanathii lipase presented high hydrolytic activity on esters bonds of triacylglycerols of long-chain, and this strain can be considered an important candidate for future applications in chemical industries.     

Is hyper-hardness more chemically relevant than expected?

In this work, the third derivative of the energy with respect to the number of electrons, the so-called hyper-hardness, is investigated to assess whether this quantity has a chemical meaning. To achieve this goal a new working expression for hyper-hardness is developed and analyzed. It transpired from this analysis that hyper-hardness, just like hardness, can measure the reactivity or the stability of electron systems. Interestingly, positive values of hyper-hardness point to quite stable species such as noble gases and molecules. On the other hand, radicals almost always display large negative values of hyper-hardness.     

Expression of DNA methyltransferases is involved in Quercus suber cork quality

Cork oak (Quercus suber) is an important Portuguese species, mainly due to the economic value of the cork it produces. Cork results from phellogen, a meristematic tissue, which can locally produce lenticels or have discontinuities, originating “defects”: pores and nail inclusions that are detrimental to cork industrial use. Epigenetic processes control plant development and its deregulation can lead to altered phenotypes; therefore, the study of epigenetic players in the phellogen is important to understand the emergence of cork's defects. DNA methyltransferases (DNMTs) and one protein associated to MET1 (DMAP1) were characterized in Q. suber, and their gene expression was analyzed in phellogen and contiguous differentiating cell layers of trees producing high and low quality cork, after the evaluation of their defects by physical and image analysis methods. All classes of DNMTs (MET, DRM, and CMT) with the respective canonical motifs were identified in Q. suber. The expression analyses of these genes showed that QsDRM2 was the most active methyltransferases in the cells analyzed, and that all the genes were differentially expressed in trees with distinct cork quality, with a tendency for higher expression levels in low quality producers. Interestingly, the global methylation level was higher in cells with low expression of DNA methyltransferases. A positive and significant correlation was obtained between QsDMAP1 gene expression and the percentage of cork defects. This work provides the first evidence that cork quality in Q. suber is likely influenced by epigenetic mechanisms.     

Identification of QTLs controlling seed dormancy in peach (Prunus persica)

Dormancy is a condition that delays or inhibits growth in seed, vegetative buds, and floral buds. In peach, seed germination occurs when seed accumulate sufficient stratification and growing degree hours to break dormancy and begin growing. Correlations have been reported between mean seed stratification requirements and mean bud chilling requirements among Prunus families, but an individual seed’s germination date and subsequent vegetative and floral bud break date are not correlated. Prior to this study, the genetic factors involved in regulating seed dormancy and their location on the peach genomic map were unknown. Segregating F₂ seed were collected from a high?×?low chill F₁ peach hybrid in 2005, 2006, and 2008. Germination date and growth habit was measured after the stratification requirement of the 2005 seed was fully met. The seed collected in 2006 and 2008 received varying amounts of stratification, which enabled data on stratification requirement, heat requirement, and growth habit to be collected. Genomic DNA was extracted from seedling leaf tissue and screened with SSR markers selected from the Prunus reference map at an average resolution of 20 cM. Seed dormancy quantitative trait loci (QTLs) were detected on G1, G4, G6/8, and G7. The QTLs detected on G6/8 and G7 were discovered in the same region as QTLs associated with floral bud chilling requirement and bloom time in peach.     

Carbon Coated ZnFe2O4 Nanoparticles for Advanced Lithium‐Ion Anodes

The preparation and electrochemical characterization of a new material consisting of carbon coated ZnFe₂O₄ nanoparticles is presented. This material, which offers an interesting combination of alloying and conversion mechanisms, is capable of hosting up to nine equivalents of lithium per unit formula, corresponding to an exceptional specific capacity, higher than 1000 mAh g^?1. Composite electrodes of such a material, prepared using environmentally friendly sodium carboxymethyl cellulose as binder, showed the highest, ever reported, specific capacity and high rate performance upon long‐term testing. Furthermore, in situ X‐ray diffraction analysis allowed identifying the reduction process occurring upon initial lithiation.     

Efficient Polymer Solar Cells on Opaque Substrates with a Laminated PEDOT:PSS Top Electrode

Solution processed polymer:fullerene solar cells on opaque substrates have been fabricated in conventional and inverted device configurations. Opaque substrates, such as insulated steel and metal covered glass, require a transparent conducting top electrode. We demonstrate that a high conducting (900 S cm^?1) PEDOT:PSS layer, deposited by a stamp‐transfer lamination technique using a PDMS stamp, in combination with an Ag grid electrode provides a proficient and versatile transparent top contact. Lamination of large size PEDOT:PSS films has been achieved on variety of surfaces resulting in ITO‐free solar cells. Power conversion efficiencies of 2.1% and 3.1% have been achieved for P3HT:PCBM layers in inverted and conventional polarity configurations, respectively. The power conversion efficiency is similar to conventional glass/ITO‐based solar cells. The high fill factor (65%) and the unaffected open‐circuit voltage that are consistently obtained in thick active layer inverted geometry devices, demonstrate that the laminated PEDOT:PSS top electrodes provide no significant potential or resistive losses.     

Tissue damage in organic rainbow trout muscle investigated by proteomics and bioinformatics

The response to tissue damage is a complex process, which involves the coordinated regulation of multiple proteins to ensure tissue repair. In order to investigate the effect of tissue damage in a lower vertebrate, samples were taken from rainbow trout (Oncorhynchus mykiss) at day 7 after damage and proteins were separated using 2DE. The experimental design included two groups of rainbow trout, which were fed organic feed either with or without astaxanthin. In total, 96 proteins were found to be affected by tissue damage, clearly demonstrating in this lower vertebrate the complexity and magnitude of the cellular response, in the context of a regenerative process. Using a bioinformatics approach, the main biological function of these proteins were assigned, showing the regulation of proteins involved in processes such as apoptosis, iron homeostasis, and regulation of muscular structure. Interestingly, it was established that exclusively within the astaxanthin feed group, three members of the annexin protein family (annexin IV, V, and VI) were regulated in response to tissue damage.     

On‐target ultrasonic digestion of proteins

In the present work, we report a novel on‐target protein cleavage method. The method utilizes ultrasonic energy and allows up to 20 samples to be cleaved in 5 min for protein identification and one sample in 30 s for on‐tissue digestion. The standard proteins were spotted on a conductive glass slide in a volume of 0.5 μL followed by 5 min of ultrasonication after trypsin addition. Controls (5 min, 37°C no ultrasonication) were also assayed. After trypsin addition, digestion of the tissues was enhanced by 30 s of ultrasonication. The samples were analyzed and compared to those obtained by using conventional 3 h heating proteolysis. The low sample volume needed for the digestion and reduction in sample‐handling steps and time are the features that make this method appealing to the many laboratories working with high‐throughput sample treatment.     

Effects of post-thaw incubation on motility,acrosomal integrity and in vitro fertilizing capacity of boar spermatozoa cryopreserved in 0.5 and 5 ml straws

The effect of post-thaw incubation (0 vs. 5 h at 15 °C) and straw size (5 vs. 0.5 ml) on motility, acrosomal integrity and in vitro fertilizing (IVF) capacity of cryopreserved boar spermatozoa was studied. In samples assessed immediately after thawing, no differences were found between the two straw sizes. After 5 h post-thaw incubation, all parameters, except polyspermy, decreased and, spermatozoa packaged in 5 ml straws showed better functional and IVF parameters than these in 0.5 ml straws.     

Effects of human activity on the distribution and abundance of an endangered Mediterranean high-mountain plant (Erysimum penyalarense)

The Iberian mountains are important biodiversity hotspots that face great immediate threats like other species-rich regions on Earth. Preservation of natural communities has historically been based on protecting them from physical disturbance. One of the most important causes of disturbance in natural communities today is human activity. Erysimum penyalarense is an endemic and endangered Mediterranean high-mountain herb. In this study, we explore the effect of environmental factors (microhabitat characteristics) and human activity on its abundance and distribution within the only remaining population of the species. Our results indicate that the species is much more abundant than previously thought. The only population known benefited from human disturbance but was negatively affected by animal disturbance and shrub encroachment. Therefore, the net effect of human activity on the species depends on the balance between the different activities carried out within its distribution range, suggesting that intermediate levels of disturbance could help preserve some endangered plants.