Assessment of Shock Pretreatment of Corn Stover Using the Carboxylate Platform

Fuels and chemicals from lignocellulosic biomass, a renewable energy source, is an attractive solution to meet ever-increasing global energy needs and reduce global climate change. In the biochemical conversion of lignocellulose, the first and the most expensive step is pretreatment. This study focuses on the efficacy of shock pretreatment, a mechanical process that uses a shockwave to alter the biomass structure. Corn stover was pretreated with lime and shock. The two pretreatments (lime-only and lime + shock) were evaluated using enzymatic hydrolysis, batch mixed-culture fermentations, and continuous countercurrent mixed-culture fermentation. In a 120-h enzymatic hydrolysis, shock pretreatment increased the glucan digestibility of SLP (submerged lime pretreatment) corn stover by 3.5% and OLP (oxidative lime pretreatment) corn stover by 2.5%. The continuum particle distribution model (CPDM) was used to simulate a four-stage continuous countercurrent mixed-culture fermentation using empirical rate models obtained from simple batch experiments. The CPDM model determined that lime + shock pretreatment increased the total carboxylic acids yield by 28.5% over lime-only pretreatment in a countercurrent fermentation with a VSLR (volatile solids loading rate) of 12 g/(L·day) and LRT (liquid retention time) of 30 days. In a semi-continuous countercurrent fermentation performed in the laboratory for 112 days with a VSLR of 1.875 g/(L·day) and LRT of 16 days, lime + shock pretreatment increased the total carboxylic acids yield by 14.8%. The experimental results matched closely with CPDM models predictions (4.05% error). Calcium carbonate and magnesium carbonate were compared as buffers for mixed-culture fermentations of lime and lime + shock pretreated corn stover. Batch fermentations at five different substrate loadings of lime and lime + shock pretreated corn stover were performed with MgCO3 and CaCO3 buffer. In batch fermentations with 100 g/L substrate, the carboxylic acid production more than doubled (2.7 times for lime and 2.6 times for lime + shock corn stover) when MgCO3 buffer was used. In addition, CPDM was used to simulate and predict the performance of a four-stage countercurrent fermentation using MgCO3 and CaCO3 buffer. CPDM predicts that in a four-stage countercurrent fermentation with a high volatile solids loading rate (VSLR 12 g/(L·day)) and low liquid residence time (LRT 10 day), using MgCO3 buffer will yield a carboxylic acid concentration of 26.1 g/L, a 22.5% increase over CaCO3 buffer. Adding shock to lime pretreatment increased the yields at all substrate loadings in both batch fermentations and CPDM model predictions. The effect of hydrogen and carbon dioxide gas concentrations in the headspace of mixed-culture fermentations was studied. Using H2:CO2 (1:1) at 1 atm in the fermenter headspace increased the total carboxylic acids by 37%. Using CO2-only in the headspace reduced the total acids by 4%, but shifted the acid spectrum toward high-molecular-weight acids

Applications, Manufacturing and Thermal Characteristics of Micro-Lattice Structures: Current State of the Art

Micro-lattice structures are emerging as multi-functional devices. They possess excellent heat transfer capabilities, energy absorption abilities, vibration control abilities, etc. The higher surface area to volume ratio of micro-lattice structures makes them suitable for heat transfer applications where compact and lightweight heat transfer mechanism is necessary such as in case of space and transportation. The heat transfer and mechanical load-bearing properties of micro-lattice structures can be tailored by altering several parameters such as the lattice strut angle, node-to-node spacing, the diameter of the strut, etc. In this paper, micro-lattice structures, their manufacturing methods, applications are reviewed and a passive heat transfer mechanism consisting of micro-lattice heat pipe is proposed for the battery thermal management system in electric vehicles

Assessment of Shock Pretreatment of Corn Stover Using the Carboxylate Platform

Fuels and chemicals from lignocellulosic biomass, a renewable energy source, is an attractive solution to meet ever-increasing global energy needs and reduce global climate change. In the biochemical conversion of lignocellulose, the first and the most expensive step is pretreatment. This study focuses on the efficacy of shock pretreatment, a mechanical process that uses a shockwave to alter the biomass structure. Corn stover was pretreated with lime and shock. The two pretreatments (lime-only and lime + shock) were evaluated using enzymatic hydrolysis, batch mixed-culture fermentations, and continuous countercurrent mixed-culture fermentation. In a 120-h enzymatic hydrolysis, shock pretreatment increased the glucan digestibility of SLP (submerged lime pretreatment) corn stover by 3.5% and OLP (oxidative lime pretreatment) corn stover by 2.5%. The continuum particle distribution model (CPDM) was used to simulate a four-stage continuous countercurrent mixed-culture fermentation using empirical rate models obtained from simple batch experiments. The CPDM model determined that lime + shock pretreatment increased the total carboxylic acids yield by 28.5% over lime-only pretreatment in a countercurrent fermentation with a VSLR (volatile solids loading rate) of 12 g/(L·day) and LRT (liquid retention time) of 30 days. In a semi-continuous countercurrent fermentation performed in the laboratory for 112 days with a VSLR of 1.875 g/(L·day) and LRT of 16 days, lime + shock pretreatment increased the total carboxylic acids yield by 14.8%. The experimental results matched closely with CPDM models predictions (4.05% error). Calcium carbonate and magnesium carbonate were compared as buffers for mixed-culture fermentations of lime and lime + shock pretreated corn stover. Batch fermentations at five different substrate loadings of lime and lime + shock pretreated corn stover were performed with MgCO3 and CaCO3 buffer. In batch fermentations with 100 g/L substrate, the carboxylic acid production more than doubled (2.7 times for lime and 2.6 times for lime + shock corn stover) when MgCO3 buffer was used. In addition, CPDM was used to simulate and predict the performance of a four-stage countercurrent fermentation using MgCO3 and CaCO3 buffer. CPDM predicts that in a four-stage countercurrent fermentation with a high volatile solids loading rate (VSLR 12 g/(L·day)) and low liquid residence time (LRT 10 day), using MgCO3 buffer will yield a carboxylic acid concentration of 26.1 g/L, a 22.5% increase over CaCO3 buffer. Adding shock to lime pretreatment increased the yields at all substrate loadings in both batch fermentations and CPDM model predictions. The effect of hydrogen and carbon dioxide gas concentrations in the headspace of mixed-culture fermentations was studied. Using H2:CO2 (1:1) at 1 atm in the fermenter headspace increased the total carboxylic acids by 37%. Using CO2-only in the headspace reduced the total acids by 4%, but shifted the acid spectrum toward high-molecular-weight acids

De novo and rare inherited mutations implicate the transcriptional coregulator TCF20/SPBP in autism spectrum disorder

BACKGROUND: Autism spectrum disorders (ASDs) are common and have a strong genetic basis, yet the cause of ∼70-80% ASDs remains unknown. By clinical cytogenetic testing, we identified a family in which two brothers had ASD, mild intellectual disability and a chromosome 22 pericentric inversion, not detected in either parent, indicating de novo mutation with parental germinal mosaicism. We hypothesised that the rearrangement was causative of their ASD and localised the chromosome 22 breakpoints. METHODS: The rearrangement was characterised using fluorescence in situ hybridisation, Southern blotting, inverse PCR and dideoxy-sequencing. Open reading frames and intron/exon boundaries of the two physically disrupted genes identified, TCF20 and TNRC6B, were sequenced in 342 families (260 multiplex and 82 simplex) ascertained by the International Molecular Genetic Study of Autism Consortium (IMGSAC). RESULTS: IMGSAC family screening identified a de novo missense mutation of TCF20 in a single case and significant association of a different missense mutation of TCF20 with ASD in three further families. Through exome sequencing in another project, we independently identified a de novo frameshifting mutation of TCF20 in a woman with ASD and moderate intellectual disability. We did not identify a significant association of TNRC6B mutations with ASD. CONCLUSIONS: TCF20 encodes a transcriptional coregulator (also termed SPBP) that is structurally and functionally related to RAI1, the critical dosage-sensitive protein implicated in the behavioural phenotypes of the Smith-Magenis and Potocki-Lupski 17p11.2 deletion/duplication syndromes, in which ASD is frequently diagnosed. This study provides the first evidence that mutations in TCF20 are also associated with ASD

A Phylogenetic Study of SPBP and RAI1: Evolutionary Conservation of Chromatin Binding Modules

Our genome is assembled into and array of highly dynamic nucleosome structures allowing spatial and temporal access to DNA. The nucleosomes are subject to a wide array of post-translational modifications, altering the DNAhistone interaction and serving as docking sites for proteins exhibiting effector or “reader” modules. The nuclear proteins SPBP and RAI1 are composed of several putative “reader” modules which may have ability to recognise a set of histone modification marks. Here we have performed a phylogenetic study of their putative reader modules, the C-terminal ePHD/ADD like domain, a novel nucleosome binding region and an AT-hook motif. Interactions studies in vitro and in yeast cells suggested that despite the extraordinary long loop region in their ePHD/ADD-like chromatin binding domains, the C-terminal region of both proteins seem to adopt a cross-braced topology of zinc finger interactions similar to other structurally determined ePHD/ADD structures. Both their ePHD/ADD-like domain and their novel nucleosome binding domain are highly conserved in vertebrate evolution, and construction of a phylogenetic tree displayed two well supported clusters representing SPBP and RAI1, respectively. Their genome and domain organisation suggest that SPBP and RAI1 have occurred from a gene duplication event. The phylogenetic tree suggests that this duplication has happened early in vertebrate evolution, since only one gene was identified in insects and lancelet. Finally, experimental data confirm that the conserved novel nucleosome binding region of RAI1 has the ability to bind the nucleosome core and histones. However, an adjacent conserved AT-hook motif as identified in SPBP is not present in RAI1, and deletion of the novel nucleosome binding region of RAI1 did not significantly affect its nuclear localisation

SPBP is a sulforaphane induced transcriptional coactivator of NRF2 regulating expression of the autophagy receptor p62/SQSTM1

Organisms exposed to oxidative stress respond by orchestrating a stress response to prevent further damage. Intracellular levels of antioxidant agents increase, and damaged components are removed by autophagy induction. The KEAP1-NRF2 signaling pathway is the main pathway responsible for cell defense against oxidative stress and for maintaining the cellular redox balance at physiological levels. Sulforaphane, an isothiocyanate derived from cruciferous vegetables, is a potent inducer of KEAP1-NRF2 signaling and antioxidant response element driven gene expression. In this study, we show that sulforaphane enhances the expression of the transcriptional coregulator SPBP. The expression curve peaks 6-8 hours post stimulation, and parallels the sulforaphane-induced expression of NRF2 and the autophagy receptor protein p62/SQSTM1. Reporter gene assays show that SPBP stimulates the expression of p62/SQSTM1 via ARE elements in the promoter region, and siRNA mediated knock down of SPBP significantly decreases the expression of p62/SQSTM1 and the formation of p62/SQSTM1 bodies in HeLa cells. Furthermore, SPBP siRNA reduces the sulforaphane induced expression of NRF2, and the expression of the autophagy marker protein LC3B. Both these proteins contain ARE-like elements in their promoter regions. Over-expressed SPBP and NRF2 acts synergistically on the p62/SQSTM1 promoter and colocalize in nuclear speckles in HeLa cells. Collectively, these results suggest that SPBP is a coactivator of NRF2, and hence may be important for securing enhanced and sustained expression of NRF2 induced genes such as proteins involved in selective autophagy

Comparison Between 8-Methoxypsoralen and 5-Aminolevulinic Acid in Killing T Cells of Photopheresis Patients Ex Vivo

Background and Objective Extracorporeal photopheresis (ECP), an established modality for cutaneous T‐cell lymphoma (CTCL) and graft‐versus‐host disease, involves ex vivo treatment of isolated leukocytes of a patient with the photosensitizing drug 8‐methoxypsoralen (8‐MOP) and ultraviolet‐A (UV‐A) exposure before reinfusion back to the patient. However, 8‐MOP binds to both diseased and normal cells and thus kills both types of the cells after UV‐A illumination with little selectivity. Clinically, this modality gives only partial response in the majority of treated patients. 5‐Aminolevulinic acid (5‐ALA), a precursor of the potent photosensitizer protoporphyrin IX (PpIX), has been shown to selectively induce PpIX in activated T lymphocytes (T cells) and could be an alternative for 8‐MOP. The objectives of this study were to investigate ex vivo 5‐ALA dark toxicity, 5‐ALA‐induced PpIX production, and photodynamic effect on T cells obtained from clinical ECP patients after the treatment of 5‐ALA or 8‐MOP plus a built‐in certified UV‐A source in the commercial Therakos™ Photopheresis System. Materials and Methods Flow cytometry was used to study dark cytotoxic effects of 5‐ALA on human leukocytes, to measure the production of 5‐ALA‐induced PpIX in CD25+ activated T cells from both diluted mononuclear cells and undiluted buffy coat samples of ECP patients and to compare photodynamic effects on CD4+ and CD8+ T cells with 5‐ALA/UV‐A or 8‐MOP/UV‐A. Results No dark toxicity of 5‐ALA on the leukocytes of ECP patients was seen at concentrations up to 10 mM for an incubation of up to 20 hours. 5‐ALA‐induced PpIX was produced more in CD25+ activated T cells than resting T cells in both diluted mononuclear cells and undiluted buffy coat samples, although there was a huge variation of samples from different individual patients. The CD4+ and CD8+ T cells treated with 5‐ALA/UV‐A were killed more than those treated with 8‐MOP/UV‐A. Conclusion These results suggest that 5‐ALA/UV‐A may have the potential for improving the efficacy of ECP. Lasers Surg. Med. 50:469–475, 2018

The RAI1 region 1523-1627 has the ability to bind nucleosomes and histones <i>in</i><i>vitro</i>.

<p>(<b>A</b>) The region of RAI1 with homology to the novel nucleosome binding region in SPBP binds HeLa nucleosomes independent of the histone tails. Intact nucleosomes isolated from HeLa cells were incubated with GST, GST-SPBP (1551-1666), and GST-RAI1(1523-1627) (left panel), and partial trypsin digested nucleosomes were incubated with GST, GST-GST-SPBP(ePHD), GST-SPBP(1551-1666), GST-RAI1(ePHD), GST-RAI1(PHD), GST-RAI1(1523-1627) and negative control GST-MLL(PHD3) (right panel) as indicated. Bound proteins were subjected to Western blotting using anti–histone H3 antibody and anti-GST antibody. (<b>B</b>) The novel nucleosome-binding region 1551-1666 of SPBP and 1523-1627 of RAI1 interacts with histones H2 and H3 variants. Labeled GFP-SPBP (1551-1666) and GFP-RAI1(1523-1627) were incubated with GST, GST-H2A, H2B, H3.1, H3.3 and H2AZ expressed and purified from <i>E. coli</i>. Interacting proteins were subjected to SDS-PAGE and visualized using a PhosphorImager. (<b>C</b>) Deletion of the novel chromatin binding region of RAI1 (1523-1627), or the ePHD domain of RAI1, has no significant impact on RAI1 distribution in the nucleus of HeLa cells. HeLa cells were transiently co-transfected with plasmid expressing mCherry-RAI1 and EGFP-RAI1 (Δ1523-1627) (upper panels), or mCherry-RAI1 and EGFP-RAI1(ΔePHD)(lower panels).</p