Effect of alkaline and autohydrolysis processes on the purity of obtained hemicelluloses from corn stalks

A study of the potential of autohydrolysis and alkaline extraction processes from corn stalks was performed for high purity hemicellulose extraction. The influence of process parameters on the purity of obtained hemicelluloses was analyzed. An experimental design was developed for the autohydrolysis treatments to determine the optimal conditions to solubilize the hemicelluloses with lowest content in contaminants. On the other hand, alkaline extraction, including raw material pretreatment (dewaxing and delignification step) was carried out analyzing the effectiveness of this processes for maximum pure hemicellulose recovery. The maximum yield (54% of the raw material hemicelluloses) and the best physicochemical properties (highest hemicellulose content free of lignin) were obtained with these pretreatments in alkaline extraction. Moreover, the effect of lignin removal by sulfuric acid from the autohydrolysis liquors before hemicellulose precipitation was studied. This purification step has allowed to obtain lignin-free autohydrolysis hemicellulose but with the presence of sulfur as predominant contaminant.     

Adaptive Long-Term Monitoring of Soil Health in Metal Phytostabilization: Ecological Attributes and Ecosystem Services Based on Soil Microbial Parametersxs

Phytostabilization is a promising option for the remediation of metal contaminated soils which requires the implementation of long-term monitoring programs. We here propose to incorporate the paradigm of “adaptive monitoring”, which enables monitoring programs to evolve iteratively as new information emerges and research questions change, to metal phytostabilization. Posing good questions that cover the chemical, toxicological and ecological concerns associated to metal contaminated soils is critical for an efficient long-term phytostabilization monitoring program. Regarding the ecological concerns, soil microbial parameters are most valuable indicators of the effectiveness of metal phytostabilization processes in terms of recovery of soil health. We suggest to group soil microbial parameters in higher-level categories such as “ecological attributes” (vigor, organization, stability) or “ecosystem services” in order to facilitate interpretation and, most importantly, to provide long-term phytostabilization monitoring programs with the required stability through time against changes in techniques, methods, interests, etc. that will inevitably occur during the monitoring program. Finally, a Phytostabilization Monitoring Card, based on both ecological attributes and ecosystem services, for soil microbial properties is provided.     

A Cholesterol Recognition Motif in Human Phospholipid Scramblase 1

Human phospholipid scramblase 1 (SCR) catalyzes phospholipid transmembrane (flip-flop) motion. This protein is assumed to bind the membrane hydrophobic core through a transmembrane domain (TMD) as well as via covalently bound palmitoyl residues. Here, we explore the possible interaction of the SCR TMD with cholesterol by using a variety of experimental and computational biophysical approaches. Our findings indicate that SCR contains an amino acid segment at the C-terminal region that shows a remarkable affinity for cholesterol, although it lacks the CRAC sequence. Other 3-OH sterols, but not steroids lacking the 3-OH group, also bind this region of the protein. The newly identified cholesterol-binding region is located partly at the C-terminal portion of the TMD and partly in the first amino acid residues in the SCR C-terminal extracellular coil. This finding could be related to the previously described affinity of SCR for cholesterol-rich domains in membranes.     

The culture of human cleavage stage embryos alone or in groups: effect upon blastocyst utilization rates and implantation

The effect of cleavage-stage group culture (CGC; embryos cultured in groups of three or more for the first 3 days and then individually to blastocyst) was compared to extended single embryo culture (ESC; embryos cultured individually to the blastocyst stage). While implantation and ongoing pregnancy rates were similar between groups, the blastocyst utilization rate (number of blastocysts suitable for freezing and thawing/total number of embryos cultured to Day 5 and 6) was significantly higher when embryos were cultured in CGC for women ≤35 yrs thereby increasing the number of embryos available for clinical use for the younger women. This strategy of group culture to Day 3 would seem an ideal protocol to capitalize on an overall embryo quality in two particular settings, namely programmes wishing to (i) undertake Day 3 transfers, and (ii) keep embryos separate from Day 3 to Day5/6 for the purposes of selection. The culture system can also be applied to the embryos of older women without adverse effect, enabling the same system to be used for all embryos.     

A biogeographical analysis of the European Atlantic lowland heathlands

Questions: What is the climatic envelope of European Atlantic heathlands and the relationship between their floristic geographical variability and climatic parameters? Are the biogeographic patterns extracted from genuine heath plants comparable to those extracted from the accompanying flora? To what extent does the species composition extracted from phytosociological data support the current theory of refuge areas of heath vegetation in southern Atlantic Europe during the Pleistocene ice ages? Location: Atlantic Europe and NW Morocco. Methods: The geographical territory in which Atlantic heathlands occur was divided into 23 sectors following geographic and chorological criteria. A presence–absence table with 333 taxa was then constructed with the available phytosociological data. The taxa were classified into different groups according to their phytosociological affinity. Several types of numerical analysis were performed with this matrix and the climatic data obtained from meteorological sources. Results: Heathlands require a humid and oceanic climate and are limited by cold temperatures in the north and by summer droughts in the south. The highest floristic richness of this vegetation type is found in NW Iberia. Ordinations indicate a strong correlation between floristic composition of biogeographic sector and summer drought (Ios) and thermicity (It). Conclusions: The main climatic factors determining lowland heathland floristic distribution are thermicity and summer drought. The current optimal conditions for heath flora in NW Iberia suggest that there were southern refuges during the Pleistocene ice ages from which northward expansion has taken place.     

Novel horizontal transmission route for Enteromyxum leei (Myxozoa) by anal intubation of gilthead sea bream Sparus aurata

The aim of the present study was to determine whether Enteromyxum leei, one of the most threatening parasitic diseases in Mediterranean fish culture, could be transmitted by peranal intubation in gilthead sea bream Sparus aurata L. Fish were inoculated either orally or anally with intestinal scrapings of infected fish in 3 trials. Oral transmission failed, but the parasite was efficiently and quickly transmitted peranally. Prevalence of infection was 100% at 60 d post inoculation (p.i.) in Trial 1 under high summer temperature (22 to 25 degrees C; fish weight = 187.1 g), and 85.7% in just 15 d p.i. in Trial 3 using smaller fish (127.5 g) at autumn temperature (19 to 22 degrees C). In Trial 2, prevalence reached 60% at 60 d p.i. in the group reared at constant temperature (18 degrees C), whereas no fish was infected in the group that was kept at low winter temperature (11 to 12 degrees C), although infection appeared (46.1% at 216 d p.i.) when temperature increased in spring. The arrested development at low temperature has important epidemiological consequences, as fish giving false negative results in winter can act as reservoirs of the parasite. Histopathological examination showed a posterior-anterior intestinal gradient in the progression of the infection, in terms of both intensity and parasite maturation. Thus, per-anal intubation provides a very uniform, reliable and faster mode of transmission of E. leei than the commonly used transmission methods (cohabitation, exposure to infected effluent and oral inoculation), which require long exposure times or give variable and unpredictable results.     

Control of directed cell migration in vivo by membrane-to-cortex attachment

Cell shape and motility are primarily controlled by cellular mechanics. The attachment of the plasma membrane to the underlying actomyosin cortex has been proposed to be important for cellular processes involving membrane deformation. However, little is known about the actual function of membrane-to-cortex attachment (MCA) in cell protrusion formation and migration, in particular in the context of the developing embryo. Here, we use a multidisciplinary approach to study MCA in zebrafish mesoderm and endoderm (mesendoderm) germ layer progenitor cells, which migrate using a combination of different protrusion types, namely, lamellipodia, filopodia, and blebs, during zebrafish gastrulation. By interfering with the activity of molecules linking the cortex to the membrane and measuring resulting changes in MCA by atomic force microscopy, we show that reducing MCA in mesendoderm progenitors increases the proportion of cellular blebs and reduces the directionality of cell migration. We propose that MCA is a key parameter controlling the relative proportions of different cell protrusion types in mesendoderm progenitors, and thus is key in controlling directed migration during gastrulation.     

Virtual Expert Mass Spectrometrist: iTRAQ tool for database‐dependent search,quantitation and result storage

A frequent goal of MS‐based proteomics experiments nowadays is to quantify changes in the abundance of proteins across several biological samples. The iTRAQ labeling method is a powerful technique; when combined with LC coupled to MS/MS it allows relative quantitation of up to eight different samples simultaneously. Despite the usefulness of iTRAQ current software solutions have limited functionality and require the combined use of several software programs for analysis of the data from different MS vendors. We developed an integrated tool, now available in the virtual expert mass spectrometrist (VEMS) program, for database‐dependent search of MS/MS spectra, quantitation and database storage for iTRAQ‐labeled samples. VEMS also provides useful alternative report types for large‐scale quantitative experiments. The implemented statistical algorithms build on quantitative algorithms previously used in proposed iTRAQ tools as described in detail herein. We propose a new algorithm, which provides more accurate peptide ratios for data that show an intensity‐dependent saturation. The accuracy of the proposed iTRAQ algorithm and the performance of VEMS are demonstrated by comparing results from VEMS, MASCOT and PEAKS Q obtained by analyzing data from a reference mixture of six proteins. Users can download VEMS and test data from “ http://www.portugene.com/software.html ”.