Numerical Modelling of Electroosmotic Driven Flow in Nanoporous Media by Lattice Boltzmann Method

The lattice Boltzmann method was employed to simulate electroosmotic driven flow and Debye layer screening in conducting electrolyte around a porous structure with average size of 40 nm. The charge screening around the nanopores was investigated by solving the vector-superpositioned potential equilibrium distribution function and adding electro-kinetic force term to the evolution equation. In this intermediate case of moderate Debye length, the electrophoresis problem becomes complicated. The motion of the particles distorts the screening cloud, which becomes asymmetric, resulting in very complex interactions between the electrolyte, the screening cloud and the particle; but the Electroosmotic Flow (EOF) behaviour was still considered based on the Helmoholtz-Smoluchowski model with adaptation to fit nanoporous flow in the porous structure. In the present approach, the flow in the nanopores is directly modelled; the detailed flow information can be obtained by simplifying the repeated macrostructure. Due to the symmetry of the domain, the size of computational domain can be largely reduced by less repeated spherical nanoparticles. Each pore of the medium contains several lattice nodes on the simplified curved edges and potential gradients are produced by adjusting the zeta potential value. The velocity results for pressure-driven and EOF flows agree well with the analytical solutions and recent experimental results. In particular, the interface between solid particles and fluids, the influences of porosity, solid particle diameter, yield stress and electric parameters in EOF were investigated. The anti-adhesion effect of electroosmotic pumping effect was evaluated, and the pulsed DC was applied in order to enhance the performance of the electroosmotic pumping. The results demonstrate that the present lattice Boltzmann model is capable of modelling flow through nanoporous media at certain restrictions while some results deviate from the predictions based on the macroscopic theories.     

Genome‐wide analysis of Nilaparvata lugens nymphal responses to high‐density and low‐quality rice hosts

The brown planthopper (BPH) Nilaparvata lugens is an economically important pest on rice plants. In this study, the higher population density and yellow‐ripe stage of rice plants were used to construct adverse survival conditions (ASC) against BPH nymphs. Simultaneously, the low population density and tillering stage of rice plants were used to establish a suitable survival condition (SSC) as a control. Solexa/Illumina sequencing was used to identify genes of BPH nymphs responding to ASC. Significantly longer duration development of BPH nymphs and significantly lower brachypterous ratio of BPH adults were observed by ASC compared with SSC. A total of 2 544 differentially expressed genes (DEGs) were obtained and analyzed by BLASTx, Gene Ontology and KEGG Orthology. Gene ontology analysis revealed that the DEGs were mainly involved in categories of cell, cell part, cellular process, binding, catalytic, organelle and metabolic processes. 1 138 DEGs having enzyme commission numbers were assigned to different metabolic pathways. The largest clusters were neurodegenerative diseases (137, 12.0%), followed by carbohydrate metabolism (113, 9.9%), amino acid metabolism (94, 8.3%), nucleotide metabolism (76, 6.7%), energy metabolism (64, 5.6%), translation (60, 5.3%), lipid metabolism (58, 5.1%), and folding, sorting and degradation (52, 4.6%). Expressing profile of 11 DEGs during eight nymphal developmental stages of BPH were analyzed by quantitative real‐time polymerase chain reaction. The 11 genes exhibited differential expression between ASC and SSC during at least one developmental stage. The DEGs identified in this study provide molecular proof of how BPH reconfigures its gene expression profile to adapt to overcrowding and low‐quality hosts.     

Morphogenesis of T-tubules in heart cells: the role of junctophilin-2

The T-tubule (TT) system forms the structural basis for excitation-contraction coupling in heart and muscle cells. The morphogenesis of the TT system is a key step in the maturation of heart cells because it does not exist in neonatal cardiomyocytes. In the present study, we quantified the morphological changes in TTs during heart cell maturation and investigated the role of junctophilin-2 (JP2), a protein known to anchor the sarcoplasmic reticulum (SR) to TT, in changes to TT morphological parameters. Analysis of confocal images showed that the transverse elements of TTs increased, while longitudinal elements decreased during the maturation of TTs. Fourier transform analysis showed that the power of ~2 m spatial components increased with cardiomyocytes maturation. These changes were preceded by increased expression of JP2, and were reversed by JP2 knockdown. These findings indicate that JP2 is required for the morphogenesis of TTs during heart development.     

Secretory/releasing proteome-based identification of plasma biomarkers in HBV-associated hepatocellular carcinoma

For successful therapy, hepatocellular carcinoma (HCC) must be detected at an early stage. Herein, we used a proteomic approach to analyze the secretory/releasing proteome of HCC tissues to identify plasma biomarkers. Serum-free conditioned media (CM) were collected from primary cultures of cancerous tissues and surrounding noncancerous tissues. Proteomic analysis of the CM proteins permitted the identification of 1365 proteins. The enriched molecular functions and biological processes of the CM proteins, such as hydrolase activity and catabolic processes, were consistent with the liver being the most important metabolic organ. Moreover, 19% of the proteins were characterized as extracellular or membrane-bound. For validation, secretory proteins involved in transforming growth factor-β signaling pathways were validated in plasma samples. Alphafetoprotein (AFP), metalloproteinase (MMP)1, osteopontin (OPN), and pregnancy-specific beta-1-glycoprotein (PSG)9 were significantly increased in HCC patients. The overall performance of MMP1 and OPN in the diagnosis of HCC remained greater than that of AFP. In addition, this study represents the first report of MMP1 as a biomarker with a higher sensitivity and specificity than AFP. Thus, this study provides a valuable resource of the HCC secretome with the potential to investigate serological biomarkers. MMP1 and OPN could be used as novel biomarkers for the early detection of HCC and to improve the sensitivity of biomarkers compared with AFP.     

Phenotypic differentiation between wild and domesticated varieties of <Emphasis Type="Italic">Crescentia cujete</Emphasis>L. and culturally relevant uses of their fruits as bowls in the Yucatan Peninsula,Mexico

Background

Selection criteria are important for analyzing domestication of perennial plant species, which experience a selection pressure throughout several human generations. We analyze the preferred morphological characteristics of Crescentia cujete fruits, which are used as bowls by the Maya of Yucatan, according to the uses they are given and the phenotypic consequences of artificial selection between one wild and three domesticated varieties.

Methods

We performed 40 semi-structured interviews in seven communities. We calculated Sutrop’s salience index (S) of five classes of ceremonial and daily life uses, and of each item from the two most salient classes. We sampled 238 bowls at homes of people interviewed and compared their shape, volume and thickness with 139 fruits collected in homegardens and 179 from the wild. Morphology of varieties was assessed in fruit (n?=?114 trees) and vegetative characters (n?=?136 trees). Differences between varieties were evaluated through linear discriminant analysis (LDA).

Results

Use of bowls as containers for the Day of the Dead offerings was the most salient class (S?=?0.489) with chocolate as its most salient beverage (S?=?0.491), followed by consumption of daily beverages (S?=?0.423), especially maize-based pozol (S?=?0.412). The sacred saka’ and balche' are offered in different sized bowls during agricultural and domestic rituals. Roundness was the most relevant character for these uses, as bowls from households showed a strong selection towards round shapes compared with wild and homegarden fruits. Larger fruits from domesticated varieties were also preferred over small wild fruits, although in the household different sizes of the domesticated varieties are useful. LDA separated wild from domesticated trees (p?<?0.001) according to both fruit and vegetative variables, but domesticated varieties were not different among themselves.

Conclusions

The association between C. cujete bowls and traditional beverages in ritual and daily life situations has driven for centuries the selection of preferred fruit morphology in this tree. Selection of fruit roundness and volume has allowed for the differentiation between the wild variety and the three domesticated ones, counteracting gene flow among them. By choosing the best fruits from domesticated varieties propagated in homegardens, the Maya people model the domestication process of this important tree in their culture.

     

Overexpression of Arabidopsis ABF3 gene confers enhanced tolerance to drought and heat stress in creeping bentgrass

The Arabidopsis, abscisic acid responsive element-binding factor 3, ABF3 is known to play an important role in stress responses via regulating the expression of stress-responsive genes. In this study, we introduced pCAMBIA3301 vector harboring the ABF3 gene into creeping bentgrass (Agrostis stolonifera) through Agrobacterium-mediated transformation in order to develop a stress-tolerant variety of turfgrass. After transformation, putative transgenic plants were selected using the herbicide resistance assay. Genomic integration of the transgene was confirmed by genomic PCR and Southern blot analysis, and gene expression was validated by northern blot analysis. Under drought-stressed condition, the transgenic plants overexpressing ABF3 displayed significantly enhanced drought tolerance with higher water content and slower water loss rate than the control plants. Furthermore, the stomata of the ABF3 transgenic plants closed more than those of wild-type creeping bentgrass plants, under both non-stressed and ABA treatment conditions. In addition, the transgenic plants showed enhanced tolerance to heat stress. These results suggest that the overexpression of the ABF3 gene in creeping bentgrass might enhance survival in water-limiting and high temperature environments through increased stomatal closure and reduced water losses.