Pretreatment of lignocellulosic wheat straw in ethanolwater co-solvents

Pretreatment is the key process for lignocellulosic biomass conversion, which is necessary to alter the structure of biomass to make cellulose and hemicellulose more accessible to the enzymes that convert the carbohydrate polymers into fermentable sugars. The present study reports the use of 15 ml ethanol-water co-solvents (1:1, v/v) for the pretreatment of lignocellulosic biomass (1.5 g) to produce cellulosic residual solid under varying conditions of temperature (220-310 °C) and time (20-100 min). Kinetic analysis was performed to examine the decomposition behavior of biomass in the co-solvents. The results showed that the optimal conditions for the pretreatment were 250 °C and 40 min. The maximum yield of residual solid under the optimized pretreatment conditions was 49.6% (0.744 g), which consisted of 91.4% holocellulose (cellulose and hemicellulose). Microstructure analysis showed that the compact monolithic structure of biomass had decomposed into a loose filamentous structure

Transcriptome analysis of Aspergillus niger xlnR and xkiA mutants grown on corn Stover and soybean hulls reveals a highly complex regulatory network.

BACKGROUND:Enzymatic plant biomass degradation by fungi is a highly complex process and one of the leading challenges in developing a biobased economy. Some industrial fungi (e.g. Aspergillus niger) have a long history of use with respect to plant biomass degradation and for that reason have become 'model' species for this topic. A. niger is a major industrial enzyme producer that has a broad ability to degrade plant based polysaccharides. A. niger wild-type, the (hemi-)cellulolytic regulator (xlnR) and xylulokinase (xkiA1) mutant strains were grown on a monocot (corn stover, CS) and dicot (soybean hulls, SBH) substrate. The xkiA1 mutant is unable to utilize the pentoses D-xylose and L-arabinose and the polysaccharide xylan, and was previously shown to accumulate inducers for the (hemi-)cellulolytic transcriptional activator XlnR and the arabinanolytic transcriptional activator AraR in the presence of pentoses, resulting in overexpression of their target genes. The xlnR mutant has reduced growth on xylan and down-regulation of its target genes. The mutants therefore have a similar phenotype on xylan, but an opposite transcriptional effect. D-xylose and L-arabinose are the most abundant monosaccharides after D-glucose in nearly all plant-derived biomass materials. In this study we evaluated the effect of the xlnR and xkiA1 mutation during growth on two pentose-rich substrates by transcriptome analysis. RESULTS:Particular attention was given to CAZymes, metabolic pathways and transcription factors related to the plant biomass degradation. Genes coding for the main enzymes involved in plant biomass degradation were down-regulated at the beginning of the growth on CS and SBH. However, at a later time point, significant differences were found in the expression profiles of both mutants on CS compared to SBH. CONCLUSION:This study demonstrates the high complexity of the plant biomass degradation process by fungi, by showing that mutant strains with fairly straightforward phenotypes on pure mono- and polysaccharides, have much less clear-cut phenotypes and transcriptomes on crude plant biomass

Chinas Rural-Urban Migration: The Structure and Gender Attributes of the Floating Rural Labor Force

This article focuses on Chinese female rural migrant workers. Based on the survey data collected in Anhui and Sichuan provinces of China, the article investigates gender aspects of Chinese rural-urban migrants in the context of the household migration model.Results of the examination indicate that the rapid economic development that China is undergoing makes it possible for rural women to go from traditional villages to modern and post-modern cities and gain employment in urban areas and VTEs (village and township enterprises). The young, unmarried, and well-educated rural women are much more likely to migrate or to get off-farm jobs, and the occupations held by these rural female workers are more varied. There are gender features among the rural-urban migrant workers. The proportion of the returnees among married women is much higher than that of their male counterparts. Income also differs between female and male laborers. While the proportion of women in the lower income group is higher than men, the proportion of female workers in the higher income groups is lower. The lack of social security for rural residents proves to be a highly signi? cant institutional barrier for rural women to access the new opportunities offered by a more open economy and the modernization process.On a more general level, the results of the study suggest that market-oriented economic reform brought about diverse effects on Chinese women in terms of labor market status. Though the institutional barriers put Chinese female rural workers in a position of disadvantage, the performance of female rural-urban migrant workers suggests that they are active beings rather than passive victims merely adapting to the social transformation. Female rural-urban migrant workers have been and still are playing important and speci? c roles at the crossover between the emerging capitalist economy and the traditional rural society. In doing so they are positive participants of globalization in a wider development perspective

Insulin regulates carboxypeptidase E by modulating translation initiation scaffolding protein eIF4G1 in pancreatic β cells

Insulin resistance, hyperinsulinemia, and hyperproinsulinemia occur early in the pathogenesis of type 2 diabetes (T2D). Elevated levels of proinsulin and proinsulin intermediates are markers of β-cell dysfunction and are strongly associated with development of T2D in humans. However, the mechanism(s) underlying β-cell dysfunction leading to hyperproinsulinemia is poorly understood. Here, we show that disruption of insulin receptor (IR) expression in β cells has a direct impact on the expression of the convertase enzyme carboxypeptidase E (CPE) by inhibition of the eukaryotic translation initiation factor 4 gamma 1 translation initiation complex scaffolding protein that is mediated by the key transcription factors pancreatic and duodenal homeobox 1 and sterol regulatory element-binding protein 1, together leading to poor proinsulin processing. Reexpression of IR or restoring CPE expression each independently reverses the phenotype. Our results reveal the identity of key players that establish a previously unknown link between insulin signaling, translation initiation, and proinsulin processing, and provide previously unidentified mechanistic insight into the development of hyperproinsulinemia in insulin-resistant states

Pyruvate kinase M2 activation may protect against the progression of diabetic glomerular pathology and mitochondrial dysfunction

Diabetic nephropathy (DN) is a major cause of end-stage renal disease, and therapeutic options for preventing its progression are limited. To identify novel therapeutic strategies, we studied protective factors for DN using proteomics on glomeruli from individuals with extreme duration of diabetes (≥ 50 years) without DN and those with histologic signs of DN. Enzymes in the glycolytic, sorbitol, methylglyoxal and mitochondrial pathways were elevated in individuals without DN. In particular, pyruvate kinase M2 (PKM2) expression and activity were upregulated. Mechanistically, we showed that hyperglycemia and diabetes decreased PKM2 tetramer formation and activity by sulfenylation in mouse glomeruli and cultured podocytes. Pkm-knockdown immortalized mouse podocytes had higher levels of toxic glucose metabolites, mitochondrial dysfunction and apoptosis. Podocyte-specific Pkm2-knockout (KO) mice with diabetes developed worse albuminuria and glomerular pathology. Conversely, we found that pharmacological activation of PKM2 by a small-molecule PKM2 activator, TEPP-46, reversed hyperglycemia-induced elevation in toxic glucose metabolites and mitochondrial dysfunction, partially by increasing glycolytic flux and PGC-1α mRNA in cultured podocytes. In intervention studies using DBA2/J and Nos3 (eNos) KO mouse models of diabetes, TEPP-46 treatment reversed metabolic abnormalities, mitochondrial dysfunction and kidney pathology. Thus, PKM2 activation may protect against DN by increasing glucose metabolic flux, inhibiting the production of toxic glucose metabolites and inducing mitochondrial biogenesis to restore mitochondrial function

Differential Consolidation and Pattern Reverberations within Episodic Cell Assemblies in the Mouse Hippocampus

One hallmark feature of consolidation of episodic memory is that only a fraction of original information, which is usually in a more abstract form, is selected for long-term memory storage. How does the brain perform these differential memory consolidations? To investigate the neural network mechanism that governs this selective consolidation process, we use a set of distinct fearful events to study if and how hippocampal CA1 cells engage in selective memory encoding and consolidation. We show that these distinct episodes activate a unique assembly of CA1 episodic cells, or neural cliques, whose response-selectivity ranges from general-to-specific features. A series of parametric analyses further reveal that post-learning CA1 episodic pattern replays or reverberations are mostly mediated by cells exhibiting event intensity-invariant responses, not by the intensity-sensitive cells. More importantly, reactivation cross-correlations displayed by intensity-invariant cells encoding general episodic features during immediate post-learning period tend to be stronger than those displayed by invariant cells encoding specific features. These differential reactivations within the CA1 episodic cell populations can thus provide the hippocampus with a selection mechanism to consolidate preferentially more generalized knowledge for long-term memory storage

Analysis of groundwater ion abnormality and its cause of centralized drinking water sources in Jieshou City, China

Groundwater provides drinking water to city and rural residents; which is also one of the chief water sources for commercial and agricultural activities in Jieshou City. We collected and analyzed the samples of 18 underground water source wells in Jieshou. We investigated whether the water was of acceptable quality and had characteristics that exceeded the standard. This study was conducted to determine the chemical characteristics of groundwater and abnormally high super-standard ions found in groundwater. The hydrogeological conditions of the study area were analyzed through data collection; through sample collection and sample testing, the characteristics and types of water chemistry were analyzed by means of mathematical statistics analysis and the Piper chart. The genesis of water chemistry was discussed using the Gibbs chart and correlation analysis; the proportional coefficient of ion molar concentration was used to judge the source, origin, and forming process of groundwater chemical composition. The results show that the groundwater is classified as marginally alkaline water, with a composition of Na-HCO3. The cations are mainly Na+, and the anions are mainly HCO3−. According to the Ⅲ water standard of groundwater quality standard and comparing the content of each ion, Na+ and F− are the primary abnormal super-standard ions, and ions and compounds are the main occurrence states. The concentrations of Na+ and F− exceed the standard for class Ⅲ water. There was a positive correlation between the abnormal Na+ and F−, and the concentration of F− increased with the increase in monitoring depth. The causes of abnormal ions were mainly determined by the lithology of the aquifer in the study area, and most of them are fluorine-containing rocks, which are transferred into groundwater through leaching or hydration. The enrichment of Na+ and F− is influenced by the local primary geological setting, hydrochemical type, hydrogeological conditions, pH and artificial activities, and the primary geological setting is the main influencing factor

Neural Population-Level Memory Traces in the Mouse Hippocampus

One of the fundamental goals in neurosciences is to elucidate the formation and retrieval of brain's associative memory traces in real-time. Here, we describe real-time neural ensemble transient dynamics in the mouse hippocampal CA1 region and demonstrate their relationships with behavioral performances during both learning and recall. We employed the classic trace fear conditioning paradigm involving a neutral tone followed by a mild foot-shock 20 seconds later. Our large-scale recording and decoding methods revealed that conditioned tone responses and tone-shock association patterns were not present in CA1 during the first pairing, but emerged quickly after multiple pairings. These encoding patterns showed increased immediate-replay, correlating tightly with increased immediate-freezing during learning. Moreover, during contextual recall, these patterns reappeared in tandem six-to-fourteen times per minute, again correlating tightly with behavioral recall. Upon traced tone recall, while various fear memories were retrieved, the shock traces exhibited a unique recall-peak around the 20-second trace interval, further signifying the memory of time for the expected shock. Therefore, our study has revealed various real-time associative memory traces during learning and recall in CA1, and demonstrates that real-time memory traces can be decoded on a moment-to-moment basis over any single trial

Visual boundary cues suffice to anchor place and grid cells in virtual reality

The hippocampal formation contains neurons responsive to an animal’s current location and orientation, which together provide the organism with a neural map of space.1,2,3 Spatially tuned neurons rely on external landmark cues and internally generated movement information to estimate position.4,5 An important class of landmark cue are the boundaries delimiting an environment, which can define place cell field position6,7 and stabilize grid cell firing.8 However, the precise nature of the sensory information used to detect boundaries remains unknown. We used 2-dimensional virtual reality (VR)9 to show that visual cues from elevated walls surrounding the environment are both sufficient and necessary to stabilize place and grid cell responses in VR, when only visual and self-motion cues are available. By contrast, flat boundaries formed by the edges of a textured floor did not stabilize place and grid cells, indicating only specific forms of visual boundary stabilize hippocampal spatial firing. Unstable grid cells retain internally coherent, hexagonally arranged firing fields, but these fields “drift” with respect to the virtual environment over periods >5 s. Optic flow from a virtual floor does not slow drift dynamics, emphasizing the importance of boundary-related visual information. Surprisingly, place fields are more stable close to boundaries even with floor and wall cues removed, suggesting invisible boundaries are inferred using the motion of a discrete, separate cue (a beacon signaling reward location). Subsets of place cells show allocentric directional tuning toward the beacon, with strength of tuning correlating with place field stability when boundaries are removed