The efficiency of two biomass pretreatment technologies, dilute acid hydrolysis and dissolution in an ionic liquid, are compared in terms of delignification, saccharification efficiency and ...saccharide yields with switchgrass serving as a model bioenergy crop. When subject to ionic liquid pretreatment (dissolution and precipitation of cellulose by anti-solvent) switchgrass exhibited reduced cellulose crystallinity, increased surface area, and decreased lignin content compared to dilute acid pretreatment. Pretreated material was characterized by powder X-ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy, Raman spectroscopy and chemistry methods. Ionic liquid pretreatment enabled a significant enhancement in the rate of enzyme hydrolysis of the cellulose component of switchgrass, with a rate increase of 16.7-fold, and a glucan yield of 96.0% obtained in 24h. These results indicate that ionic liquid pretreatment may offer unique advantages when compared to the dilute acid pretreatment process for switchgrass. However, the cost of the ionic liquid process must also be taken into consideration.
Cellulose is inherently resistant to breakdown, and the native crystalline structure (cellulose I) of cellulose is considered to be one of the major factors limiting its potential in terms of ...cost-competitive lignocellulosic biofuel production. Here we report the impact of ionic liquid pretreatment on the cellulose crystalline structure in different feedstocks, including microcrystalline cellulose (Avicel), switchgrass ( Panicum virgatum ), pine ( Pinus radiata ), and eucalyptus ( Eucalyptus globulus ), and its influence on cellulose hydrolysis kinetics of the resultant biomass. These feedstocks were pretreated using 1-ethyl-3-methyl imidazolium acetate (C2mimOAc) at 120 and 160 °C for 1, 3, 6, and 12 h. The influence of the pretreatment conditions on the cellulose crystalline structure was analyzed by X-ray diffraction (XRD). On a larger length scale, the impact of ionic liquid pretreatment on the surface roughness of the biomass was determined by small-angle neutron scattering (SANS). Pretreatment resulted in a loss of native cellulose crystalline structure. However, the transformation processes were distinctly different for Avicel and for the biomass samples. For Avicel, a transformation to cellulose II occurred for all processing conditions. For the biomass samples, the data suggest that pretreatment for most conditions resulted in an expanded cellulose I lattice. For switchgrass, first evidence of cellulose II only occurred after 12 h of pretreatment at 120 °C. For eucalyptus, first evidence of cellulose II required more intense pretreatment (3 h at 160 °C). For pine, no clear evidence of cellulose II content was detected for the most intense pretreatment conditions of this study (12 h at 160 °C). Interestingly, the rate of enzymatic hydrolysis of Avicel was slightly lower for pretreatment at 160 °C compared with pretreatment at 120 °C. For the biomass samples, the hydrolysis rate was much greater for pretreatment at 160 °C compared with pretreatment at 120 °C. The result for Avicel can be explained by more complete conversion to cellulose II upon precipitation after pretreatment at 160 °C. By comparison, the result for the biomass samples suggests that another factor, likely lignin−carbohydrate complexes, also impacts the rate of cellulose hydrolysis in addition to cellulose crystallinity.
Over 160 publications related to fermentative hydrogen production from wastewater and solid wastes by mixed cultures are compiled and analyzed. Of the 98 reported cases, 57 used single substrates ...(mainly carbohydrates), 8 used actual wastewater, and 33 used solid wastes for hydrogen conversion. The key information is compiled in four tables: (1) pretreatment conditions for screening hydrogen-producing bacteria from anaerobic sludge or soil, and the process and performance parameters for (2) single substrates in synthetic wastewaters, (3) actual wastewaters, and (4) solid wastes. Process parameters discussed include pH, temperature, hydraulic retention time, seed sludge, nutrients, inhibitors, reactor design, and the means used for lowering hydrogen partial pressure. Performance parameters discussed include hydrogen yield, maximum volumetric production rate, maximum specific production rate, and conversion efficiency. The outlook for this new technology is discussed at the end.
This study was conducted to investigate the toxicity of six electroplating metals on the H
2-producing activity of a granular sludge sampled from an H
2-producing upflow reactor treating ...sucrose-containing wastewater. The H
2 production activities of the sludge were measured in serum vials using wastewater containing not just sucrose and proper nutrient, but also individual heavy metals at concentrations ranging 0–5000
mg
l
−1. The relative toxicity to H
2 production was found in the following order: Cu (most toxic)
≫
Ni
∼
Zn
>
Cr
>
Cd
>
Pb (least toxic). The
C
I,50 values, at which the bioactivity of the sludge was reduced to 50% of the control, for individual heavy metals were Cu 30
mg
l
−1, Ni and Zn 1600
mg
l
−1, Cr 3000
mg
l
−1, Cd 3500
mg
l
−1, and Pb >5000
mg
l
−1. Compared with the literature data, H
2-producing sludge exhibited in general higher resistance to metal toxicity than methanogenic granular sludge.
miR-139-5p has a tumor suppressor effect in some cancers and negatively regulates CXCR4. To this end, we examined the expression and mechanism of of action of miR-139-5p and CXCR4 in oral squamous ...cell carcinoma (OSCC). miRNA-139-5p was down-regulated whereas CXCR4 was increased in tissues and cells of OSCC. Moreover, low expression of miR-139-5p was associated with a low survival. Overexpression of miR-139-5p in OSCC inhibited
and
cell proliferation and
mobility of OSCC and inhibited the expression of WNT responsive c-myc, cyclinD1, and Bcl-2, and such effects were all reversible by an inhibitor of miR-139-5p or over-expression of CXCR4. The inverse relation between expression of miR-139-5p and CXCR4 might be related to the fact that miR-139-5p negatively regulates CXCR4 expression by virtue of direct binding. These findings underscore the importance of miR-139-5p and CXCR4 in regulation of OSCC.
Pine, eucalyptus, and switchgrass were evaluated for the production of fermentable sugars via ionic liquid and dilute acid pretreatments and subsequent enzymatic hydrolysis. The results show that ...among the three feedstocks, switchgrass has the highest sugar yields and faster hydrolysis rates for both pretreatment technologies by achieving 48 % (dilute acid) and 96 % (ionic liquid) sugar yields after 24 h. Of the two wood species, eucalyptus has a higher and faster sugar recovery after ionic liquid pretreatment than pine (93 vs. 62 % in 24 h) under 160 °C for 3 h with C
2
mimOAc. Pretreatment of pine and eucalyptus is observed to be ineffective under 1.2 % dilute acid condition and 160 °C for 15 min, indicating that further enhancement of reaction temperature or acid concentration is necessary to increase the digestibility of pretreated materials. Raman spectroscopy data show that the extent of lignin depolymerization that occurs during pretreatment also varies for the three different feedstocks. Under similar hemicellulose removal conditions, lignin removal in ionic liquid pretreatment can help improve cellulose conversion. This finding may help explain the observed variation in the saccharification yields and kinetics. These results indicate that ionic liquid pretreatment not only improved saccharification over dilute acid for all three feedstocks but also better dealt with the differences among them, suggesting better tolerance to feedstock variability.
The main approach to treat HIV-1 infection is combination antiretroviral therapy (cART). Although cART is effective in reducing HIV-1 viral load and controlling disease progression, it has many side ...effects, and is expensive for HIV-1 infected patients who must remain on lifetime treatment. HIV-1 gene therapy has drawn much attention as studies of genome editing tools have progressed. For example, zinc finger nucleases (ZFN), transcription activator like effector nucleases (TALEN) and clustered regularly interspaced short palindromic repeats (CRISPR)-Cas9 have been utilized to successfully disrupt the HIV-1 co-receptors CCR5 or CXCR4, thereby restricting HIV-1 infection. However, the effects of simultaneous genome editing of CXCR4 and CCR5 by CRISPR-Cas9 in blocking HIV-1 infection in primary CD4
T cells has been rarely reported. Furthermore, combination of different target sites of CXCR4 and CCR5 for disruption also need investigation.
In this report, we designed two different gRNA combinations targeting both CXCR4 and CCR5, in a single vector. The CRISPR-sgRNAs-Cas9 could successfully induce editing of CXCR4 and CCR5 genes in various cell lines and primary CD4
T cells. Using HIV-1 challenge assays, we demonstrated that CXCR4-tropic or CCR5-tropic HIV-1 infections were significantly reduced in
- and
-modified cells, and the modified cells exhibited a selective advantage over unmodified cells during HIV-1 infection. The off-target analysis showed that no non-specific editing was identified in all predicted sites. In addition, apoptosis assays indicated that simultaneous disruption of CXCR4 and CCR5 in primary CD4
T cells by CRISPR-Cas9 had no obvious cytotoxic effects on cell viability.
Our results suggest that simultaneous genome editing of CXCR4 and CCR5 by CRISPR-Cas9 can potentially provide an effective and safe strategy towards a functional cure for HIV-1 infection.
Brassinosteriod (BR) plays important roles in regulation of plant growth, development and environmental responses. BR signaling regulates multiple biological processes through controlling the ...activity of BES1/BZR1 regulators. Apart from the roles in the promotion of plant growth, BR is also involved in regulation of the root foraging response under low nitrogen, however how BR signaling regulate this process remains unclear. Here we show that BES1 and LBD37 antagonistically regulate root foraging response under low nitrogen conditions. Both the transcriptional level and dephosphorylated level of BES1, is significant induced by low nitrogen, predominantly in root. Phenotypic analysis showed that
gain-of-function mutant or
overexpression transgenic plants exhibits progressive outgrowth of lateral root in response to low nitrogen and BES1 negatively regulates repressors of nitrate signaling pathway and positively regulates several key genes required for NO
uptake and signaling. In contrast,
knock-down mutant
exhibited a dramatical reduction of lateral root elongation in response to low N. Furthermore, we identified a BES1 interacting protein, LBD37, which is a negative repressor of N availability signals. Our results showed that BES1 can inhibit LBD37 transcriptional repression on N-responsive genes. Our results thus demonstrated that BES1-LBD37 module acts critical nodes to integrate BR signaling and nitrogen signaling to modulate the root forging response at LN condition.
Aim To investigate the correlation of the triglyceride-glucose (TyG) index and its combined obesity indicators with chest pain and cardiovascular disease (CVD) in the pre-diabetes and diabetes ...population. Methods This cross-sectional investigation encompassed 6488 participants with diabetes and pre-diabetes who participated in the National Health and Nutrition Examination Survey (NHANES) between 2007 and 2016. The association of the TyG and combined obesity index with chest pain and CVD was investigated using weighted logistic regression models and restricted cubic spline (RCS) analysis. The receiver operating characteristic (ROC) curve analysis was performed to compare different indicators. Results In multivariate logistic regression fully adjusted for confounding variables, our analyses revealed significant associations between TyG, TyG-BMI, TyG-WC, and TyG-WHtR and chest pain, with adjusted ORs (95% CI) of 1.21 (1.05, 1.39), 1.06 (1.01, 1.11), 1.08 (1.04, 1.14), and 1.27 (1.08, 1.48), respectively. For total-CVD, the adjusted ORs (95% CI) were 1.32 (1.08, 1.61), 1.10 (1.03, 1.17), 1.13 (1.06, 1.19), and 1.63 (1.35, 1.97), respectively, among which TyG, TyG-WC, and TyG-WHtR present curvilinear associations in RCS analysis (all P -nonlinear < 0.05). Furthermore, the ROC curve showed that TyG-WC had the most robust predictive efficacy for total-CVD, coronary heart disease (CHD), and myocardial infarction (MI), while TyG-WHtR had the best predictive ability for angina and heart failure. Conclusion There are significant associations of TyG and its related indicators with chest pain and total-CVD among the pathoglycemia population. TyG-WC and TyG-WHtR demonstrated superior predictive capability for the incidence of cardiovascular events.
PDF
