Enhanced direct gaseous CO2 fixation into higher bio-succinic acid production and selectivity

Utilizing CO2 for bio-succinic acid production is an attractive approach to achieve carbon capture and recycling (CCR) with simultaneous production of a useful platform chemical. Actinobacillus succinogenes and Basfia succiniciproducens were selected and investigated as microbial catalysts. Firstly, the type and concentration of inorganic carbon concentration and glucose concentration were evaluated. 6 g C/L MgCO3 and 24 g C/L glucose were found to be the optimal basic operational conditions, with succinic acid production and carbon yield of over 30 g/L and over 40%, respectively. Then, for maximum gaseous CO2 fixation, carbonate was replaced with CO2 at different ratios. The "less carbonate more CO2" condition of the inorganic carbon source was set as carbonate: CO2 = 1:9 (based on the mass of carbon). This condition presented the highest availability of CO2 by well-balanced chemical reaction equilibrium and phase equilibrium, showing the best performance with regarding CO2 fixation (about 15 mg C/(L·hr)), with suppressed lactic acid accumulation. According to key enzymes analysis, the ratio of phosphoenolpyruvate carboxykinase to lactic dehydrogenase was enhanced at high ratios of gaseous CO2, which could promote glucose conversion through the succinic acid path. To further increase gaseous CO2 fixation and succinic acid production and selectivity, stepwise CO2 addition was evaluated. 50%-65% increase in inorganic carbon utilization was obtained coupled with 20%-30% increase in succinic acid selectivity. This was due to the promotion of the succinic acid branch of the glucose metabolism, while suppressing the pyruvate branch, along with the inhibition on the conversion from glucose to lactic acid.

[SRSF2 promotes glioblastoma cell proliferation by inducing alternative splicing of FSP1 and inhibiting ferroptosis]

Objective: To investigate the effect of serine/arginine-rich splicing factor 2 (SRSF2) on ferroptosis and its possible mechanism in glioblastoma cells. Methods: The online database of gene expression profiling interactive analysis 2 (GEPIA 2) and Chinese Glioma Genome Atlas were used to analyze the expression of SRSF2 in glioblastoma tissue and its association with patients prognosis. To validate the findings of the online databases, the pathological sections of glioblastoma and non-tumor brain tissues from Tianjin Medical University General Hospital, Tianjin, China were collected and analyzed by using immunohistochemistry. Silencing SRSF2 gene expression in glioblastoma cells by siRNA was analyzed with Western blot. The proliferation index was detected by using CCK8 assay. The rescued experiment was conducted by using expression plasmid of pcDNA3.1(+)-SRSF2. The activity of ferroptosis was assessed by using the levels of iron ions and malondialdehyde in glioblastoma cells and the changes in the ratio of glutathione to oxidized glutathione. The changes of gene expression and differential pre-mRNA alternative splicing (PMAS) induced by SRSF2 were monitored by using the third-generation sequencing technology analysis, namely Oxford nanopore technologies (ONT) sequencing analysis. Results: SRSF2 expression was higher in glioblastoma tissues than non-tumor brain tissues. Immunohistochemistry also showed a positive rate of 88.48%±4.60% in glioblastoma tissue which was much higher than the 9.97%±4.57% in non-tumor brain tissue. The expression of SRSF2 was inversely correlated with overall and disease-free disease survivals (P<0.01). The proliferation index of glioblastoma cells was significantly reduced by silencing with SRSF2 siRNA (P<0.01) and could be reversed with transfection of exogenous SRSF2. The levels of intracellulariron ions and malondialdehyde increased (P<0.05), but the glutathione/oxidized glutathione ratio and the expression of key proteins in the glutathione pathway remained unchanged (P>0.05). ONT sequencing results showed that silencing SRSF2 in glioblastoma cells could induce a significant alternative 3' splice site change on ferroptosis suppressor protein 1 (FSP1). Conclusion: SRSF2 inhibits the ferroptosis in glioblastoma cells and promotes their proliferation, which may be achieved by regulating FSP1 PMAS.

The integrated production of hydrochar and methane from lignocellulosic fermentative residue coupling hydrothermal carbonization with anaerobic digestion

The popularization of large-scale biogas project makes the disposal of fermentative residue an urgent issue to be solved. Hydrothermal carbonization (HTC) technology is suitable for treating wet biomass to produce carbonaceous materials. In this study, the solid residue from the two-phase anaerobic digestion (AD) was hydrothermally converted in the range of 180-240 °C, and the hydrochar and aqueous components were characterized for subsequent utilization. The heating values of hydrochar were indicated to be increased by 14.2% and 16.6% at 210 °C and 240 °C as compared with feedstock, and also the specific surface areas were 34.8 m2/g and 27.1 m2/g with 17.4- and 13.3-fold enhancement, respectively. The migration of elements such as S, Cl, K to aqueous phase was beneficial for fuel application. The mesoporous pores were dominant in hydrochars with ample oxygenated functional groups. In addition, the wastewater involved organic acids, phenols, and nitrogen-containing compounds, etc. Evaluating the biodegradability by AD, it was found that when the initial concentration was ≤8 g COD/L, the maximum methane yields up to 275.9 mL CH4/g CODremoval and 277.6 mL CH4/g CODremoval were obtained. The enhanced toxicity/inhibition of representative pollutants on microorganisms was significant at higher organic loading, which could be indicated in the microbial structure and diversity. As a conclusion, the integrated production of hydrochar and methane will provide an extended route for further processing of lignocellulosic fermentative residue.

Effect of Torrefaction on the Physiochemical Characteristics and Pyrolysis of the Corn Stalk

Torrefaction of biomass is one of the most promising pretreatment methods for deriving biofuels from biomass via thermochemical conversion processes. In this work, the changes in physicochemical properties and morphology features of the torrefied corn stalk, the changes in physicochemical properties and morphology features of the torrefied corn stalk were investigated. The results of this study showed that the elemental content and proximate analysis of the torrefied corn stalk significantly changed compared with those of the raw corn stalk. In particular, at 300 °C, the volatile content decreased to 41.79%, while the fixed carbon content and higher heating value increased to 42.22% and 21.31 MJ/kg, respectively. The H/C and O/C molar ratios of torrefied corn stalk at the 300 °C were drastically reduced to 0.99 and 0.27, respectively, which are similar to those of conventional coals in China. Numerous cracks and pores were observed in the sample surface of torrefied corn stalk at the torrefaction temperature range of 275 °C-300 °C, which could facilitate the potential application of the sample in the adsorption process and promote the release of gas products in pyrolysis. In the pyrolysis phase, the liquid products of the torrefied corn stalk decreased, but the H2/CO ratio and the lower heating value of the torrefied corn stalk increased compared with those of the raw corn stalk. This work paves a new strategy for the investigation of the effect of torrefaction on the physiochemical characteristics and pyrolysis of the corn stalk, highlighting the application potential in the conversion of biomass.

[Population structure of food-borne Staphylococcus aureus in China]

Objective: To understand the population structure of food-borne Staphylococcus (S.) aureus in China. Methods: Whole genome sequencing was used to analyze 763 food-borne S. aureus strains from 16 provinces in China from 2006 to 2020. Multilocus sequence typing (MLST), staphylococcal protein A gene (spa) typing, and staphylococcal chromosome cassettemec (SCCmec) typing were conducted, and minimum spanning tree based on ST types (STs) was constructed by BioNumerics 7.5 software. Thirty-one S. aureus strains isolated from imported food products were also included in constructing the genome phylogenetic tree. Results: A total of 90 STs (20 novel types) and 160 spa types were detected in the 763 S. aureus isolates. The 72 STs (72/90, 80.0%) were related to 22 clone complexes. The predominant clone complexes were CC7, CC1, CC5, CC398, CC188, CC59, CC6, CC88, CC15, and CC25, accounting for 82.44% (629/763) of the total. The STs and spa types in the predominant clone complexes changed over the years. The methicillin-resistant S. aureus (MRSA) detection rate was 7.60%, and 7 SCCmec types were identified. The ST59-t437-Ⅳa (17.24%, 10/58), ST239-t030-Ⅲ (12.07%, 7/58), ST59-t437-Ⅴb (8.62%, 5/58), ST338-t437-Ⅴb (6.90%, 4/58) and ST338-t441-Ⅴb (6.90%, 4/58) were the main types in MRSA strains. The genome phylogenetic tree had two clades, and the strains with the same CC, ST, and spa types clustered together. All CC7 methicillin sensitive S. aureus strains were included in Clade1, while 21 clone complexes and all MRSA strains were in Clade2. The MRSA strains clustered according to the SCCmec and STs. The strains from imported food products in CC398, CC7, CC30, CC12, and CC188 had far distances from Chinese strains in the tree. Conclusions: In this study, the predominant clone complexes of food-borne strains were CC7, CC1, CC5, CC398, CC188, CC59, CC6, CC88, CC15, and CC25, which overlapped with the previously reported clone complexes of hospital and community-associated strains in China, suggesting that close attention needs to be paid to food, a vehicle of pathogen transmission in community and food poisoning.

[Study of the urban-impact on microbial communities and their virulence factors and antibiotic resistance genomes in the Nandu River, Haikou]

Objective: To explore the changes in bacterial community structure, antibiotic resistance genome, and pathogen virulence genome in river water before and after the river flowing through Haikou City and their transmission and dispersal patterns and to reveal anthropogenic disturbance's effects on microorganisms and resistance genes in the aquatic environment. Methods: The Nandu River was divided into three study areas: the front, middle and rear sections from the upstream before it flowed through Haikou City to the estuary. Three sampling sites were selected in each area, and six copies of the sample were collected in parallel at each site and mixed for 3 L per sample. Microbial community structure, antibiotic resistance, virulence factors, and mobile genetic elements were analyzed through bioinformatic data obtained by metagenomic sequencing and full-length sequencing of 16S rRNA genes. Variations in the distribution of bacterial communities between samples and correlation of transmission patterns were analyzed by principal co-ordinates analysis, procrustes analysis, and Mantel test. Results: As the river flowed through Haikou City, microbes' alpha diversity gradually decreased. Among them, Proteobacteria dominates in the bacterial community in the front, middle, and rear sections, and the relative abundance of Proteobacteria in the middle and rear sections was higher than that in the front segment. The diversity and abundance of antibiotic resistance genes, virulence factors, and mobile genetic elements were all at low levels in the front section and all increased significantly after flow through Haikou City. At the same time, horizontal transmission mediated by mobile genetic elements played a more significant role in the spread of antibiotic-resistance genes and virulence factors. Conclusions: Urbanization significantly impacts river bacteria and the resistance genes, virulence factors, and mobile genetic elements they carry. The Nandu River in Haikou flows through the city, receiving antibiotic-resistant and pathogen-associated bacteria excreted by the population. In contrast, antibiotic-resistant genes and virulence factors are enriched in bacteria, which indicates a threat to environmental health and public health. Comparison of river microbiomes and antibiotic resistance genomes before and after flow through cities is a valuable early warning indicator for monitoring the spread of antibiotic resistance.

An Inflammation-Associated Prognosis Model for Hepatocellular Carcinoma Based on Adenylate Uridylate- (AU-) Rich Element Genes

Hepatocellular carcinoma (HCC) is a typical inflammation-driven cancer and ranks sixth in the incidence rate worldwide. The role of adenylate uridylate- (AU-) rich element genes (AREGs) in HCC remains unclear. HCC-related datasets were acquired from The Cancer Genome Atlas (TCGA) database and Gene Expression Omnibus (GEO) database. Differentially expressed AREGs (DE-AREGs) between HCC samples and healthy controls were identified. The univariate Cox and LASSO analyses were performed to determine the prognostic genes. Furthermore, a signature and corresponding nomogram were configured for the clinical prediction of HCC. The potential signature-related biological significance was explored using functional and pathway enrichment analysis. Additionally, immune infiltration analysis was also performed. Finally, the expression of prognostic genes was verified using real-time quantitative polymerase chain reaction (RT-qPCR). A total of 189 DE-AREGs between normal and HCC samples were identified, wherein CENPA, TXNRD1, RABIF, UGT2B15, and SERPINE1 were selected to generate an AREG-related signature. Moreover, the prognostic accuracy of the AREG-related signature was also confirmed. Functional analysis indicated that the high-risk score was related to various functions and pathways. Inflammation and immune-related analyses indicated that the difference of T cell and B cell receptor abundance, microvascular endothelial cells (MVE), lymphatic endothelial cells (lye), pericytes, stromal cells, and the six immune checkpoints was statistically significant between the different risk groups. Similarly, RT-qPCR outcomes of these signature genes were also significant. In conclusion, an inflammation-associated signature based on five DE-AREGs was constructed, which could act as a prognostic indicator of patients with HCC.

Energy recovery from high ash-containing sewage sludge: Focusing on performance evaluation of bio-fuel production

Hydrothermal liquefaction (HTL) has shown great potential to convert sewage sludge (SS) with high moisture into bio-crude. However, the disposal and reutilization of hydrothermal liquefaction wastewater (HTLWW) is a critical issue. Anaerobic digestion (AD) is proven to be an alternative to treat organic wastewater. Therefore, energy recovery from high ash-containing SS was studied by integrating AD with HTL. The effect of temperature on HTL efficiency was investigated and then methane production from HTLWW was conducted by AD with organic loading increasing from 2 g COD/L to 6 g COD/L. Results showed that the maximum bio-crude yield of 23.5 % was obtained at 350 °C. Methane yield of 309.4 mL CH₄/g COD_removed was achieved at 2 g COD/L with COD removal rate of 72.5 %. Meanwhile, the microbial structure and abundance showed great shifts resulting from the adaptation to complex compounds. JGI-000079-D21, Aminicenantales, and Bacteroidetes_ vadinHA17 predominated in the bacterial community. Due to the presence of the toxic substances in HTLWW, such as phenolic and nitrogenous heterocyclic compounds, there was a decrease in methane yield when the organic loading was higher than 4 g COD/L. The organic matters in extracellular polymeric substances (EPS) were rich in fulvic acid-like and humic acid-like substances due to the attack and stimulation of toxicants. Under the condition of unstable fermentation, Advenella and Bacillus first appeared as phenol and pyridine degrading bacteria, respectively. The microbial diversity declined sharply to demonstrate the toxic effect of the refractory organics existing at high organic loading. The enrichment of Methanosaeta in methanogens meant that acetotrophic metabolism is the dominant pathway in methanogenesis. In this study, the profile of bio-fuel production from high ash-containing SS would provide an integrated reference to treat wet biomass and recover energy simultaneously.

Anaerobic digestion of wood vinegar wastewater using domesticated sludge: Focusing on the relationship between organic degradation and microbial communities (archaea, bacteria, and fungi)

Thermochemical process of biomass is one of the promising renewable energy technologies; however, the by-product (wood vinegar wastewater) is rich in refractory organics, which is harmful to the environment and inhibits the conversion efficiency of microorganisms. Consequently, the dominant functional microbial communities corresponding to the various substrate were obtained through the continuous domestication, and the relationship between the dominant functional communities and the degradation of organic compounds was comprehensively analyzed. The bacterial community was absolutely dominant (approximately 85%), while archaea and fungi had similar relative abundance. The diversity showed that glucose was not conducive to the development of microbial diversity, while the substrate containing wood vinegar wastewater showed the opposite trend. The functional analysis revealed that the enrichment of bacteria associated with the hydrolysis and acidification of organics increased in the domestication process. Glucose facilitated hydrogen-trophic methanogenesis as the main methanogenic pathway in the methanogenic stage.

Preparation and Properties of a Sulphoaluminate Magnesium-Potassium Phosphate Green Cementitious Composite Material from Industrial Solid Wastes

The preparation of high-performance green cementitious material from industrial solid waste is a feasible large-scale utilization approach for industrial solid waste. This work investigates the feasibility of using industrial solid wastes in a sulphoaluminate–magnesium–potassium–phosphate cementitious composite material (SAC-MKPC) clinker preparation and the influence of the calcination temperature and clinker ingredients on the hydration behavior and mechanisms of the SAC-MKPC with a Mg/P ratio of 5. The results show that the novel SAC-MKPC that was prepared from aluminum slag, carbide slag, coal gangue, and magnesium desulfurization slag was composed mainly of mineral MgO, C4A3S¯, and C₂S and the calcination temperature of the main mineral phases was 1250–1350 °C. The solid-waste-based SAC-MKPC had better mechanical properties and excellent water resistance compared with the MKPC. The optimal compressive strength reached 35.2, 70.9, 84.1, 87.7, and 101.6 MPa at 2 h, 1 d, 3 d, 7 d, and 28 d of hydration, respectively. The X-ray diffraction spectra and scanning electron micrographs of the hydration products of the SAC-MKPC clinker showed that AFt and K-struvite crystals coexisted and adhered to form a dense structure. This work provides an innovative idea to produce green cementitious material using industrial solid wastes and may promote the sustainable development of the power and mining industries.

The role of alternative oxidase in plant hypersensitive response

The innate immune system of plants is crucial in defining the fate of a plant cell during plant-pathogen interactions. This response is often accompanied by a hypersensitive reaction leading to the death of a plant cell and restricted pathogen growth. Plant mitochondria, in this case, play a key role by maintaining a balance between cell respiration and reactive oxygen species formation. One of the key features of the hypersensitive response is the shift of the normal plant respiratory pathway to a special 'alternative' pathway. Plants contain an enzyme, alternative oxidase, for maintaining metabolic homeostasis of the cell. This energy dissipating respiration provides a branch in normal respiration by using ubiquinone to form water and heat, thus maintaining the energy status of the cell. Alternative oxidase is thought to minimize production of reactive oxygen species and can also function in 'anti-apoptotic' machinery in plant cells. In this mini review, we briefly describe the alternative respiratory pathway and explain the role of alternative oxidase in important cellular processes, such as programmed cell death and the hypersensitive response.

Effect of microaerobic microbial pretreatment on anaerobic digestion of a lignocellulosic substrate under controlled pH conditions

The effects of various microaeration strategies and process parameters on anaerobic digestion (AD) of lignocellulosic substrates have received increased attention; however, different results have been reported. To determine optimal conditions and clarify the mechanisms influencing this process, the effect of pretreatment of microaerobic microbial on corn stover decomposition and AD was investigated with real-time pH control. Fresh cow manure was chosen as the inoculum, as it has the strongest cellulose hydrolysis capacity under microaeration conditions. Microaeration microbial pretreatment effectively promoted the hydrolysis and acidogenesis of corn stover, and pH considerably affected total solid reduction, volatile fatty acid (VFA), and accumulation of soluble chemical oxygen demand (sCOD) patterns by shifting microbial communities. Different pH levels and pretreatment times led to positive and negative effects on methane yield. A 12-h pretreatment of substrate at pH 8 prior to AD increased the methane yield by 16.6% in comparison with the un-pretreated sample.

Effect of different glucogenic to lipogenic nutrient ratios on rumen fermentation and bacterial community in vitro

Aims

This study was to investigate the effect of different ratios of glucogenic to lipogenic nutrients on rumen fermentation and the corresponding ruminal bacterial communities.

Methods and Results

Four diets, including glucogenic diet (G), lipogenic diet (L), two mixed diets: GL1 (G: L = 2 : 1) and GL2 (G:L = 1 : 2), served as substrates and were incubated with rumen fluid in vitro. The results revealed that the gas production, dry matter digestibility and propionate proportion were significantly increased by the G diet than others. The G diet increased the bacterial genera of Succinivibrionaceae_UCG_002, Succinivibrio, Selenomonas_1 and Ruminobacter but decreased some cellulolytic bacteria including the Eubacterium and several genera in family Ruminococcaceae than others.

Conclusions

When the glucogenic nutrient was above 1/3 of the dietary energy source among the four diets, the in vitro incubation had a higher feed digestibility and lower acetate to propionate ratio. Bacterial genera, including Selenomonas, Succinivibrio, Ruminobacter, certain genera in Ruminococcaceae, Christensenellaceae_R‐7_group and Eubacterium, were more sensitive to the glucogenic to lipogenic nutrients ratio.

Significance and Impact of the Study

The present study provides a new perspective about the effect of dietary glucogenic to lipogenic ingredient ratios on rumen metabolism by comparing end‐products, gas production and bacterial composition via an in vitro technique.

Comparison of methanogenic potential of wood vinegar with gradient loads in batch and continuous anaerobic digestion and microbial community analysis

Anaerobic digestion (AD) of wood vinegar wastewater (WVWW) has considerable potential in energy recovery and sustainable development. WVWW contains abundant acetic acid and some refractory organics. Therefore, the batch and continuous AD of WVWW were investigated. The threshold value of the inhibitory concentration was obtained at a chemical oxygen demand (COD) of 4 g/L in batch AD. Three-dimensional electrolysis was adopted to improve the biodegradability of WVWW, and a reduction in the inhibitory rate from 38.2% to 4.9% and an increase in methane production by 53.8% were observed. The up-flow anaerobic sludge blanket reactor achieved an efficient conversion of methane at an organic loading rate (OLR) of <8.58 g COD/L·d. However, the OLR of 10.01 g COD/L·d decreased the methane production from 350.6 to 42.5 mL CH₄/g COD_fed. Aminicenantales, Acetobacterium, Anaerolineae, and SBR1031 were the dominant bacterial genera in continuous AD. Fewer genera with similar classifications were detected in the batch AD. In the archaea community, acetotrophic methanogens (Methanosaeta) dominated and increased continuously with increasing OLR. Microbial analysis revealed that toxic substances affected bacterial diversity and promoted the enrichment of Intestinimonas, Syntropobacter, and Propionicimonas at high OLRs. The continuous AD was most suitable for the energy recovery from WVWW.

AK5, a novel prognosis marker, inhibits apoptosis and promotes autophagy as well as proliferation in human gastric cancer

OBJECTIVE

To explore the relationship between AK5 and gastric cancer.

MATERIALS AND METHODS

The in situ levels of AK5 in the GC tissues from 255 patients were detected by immunohistochemistry (IHC). The correlation between AK5 expression and the clinicopathological parameters was analyzed by Pearson correlation, and the prognostic factors were identified by Cox regression analysis. The transcriptome data of 14 human GC cell lines deposited in the CCLE database were analyzed, and two lines were selected for functional studies. AK5 was knocked down in the AZ521 and MKN74 cells using siRNA, and their proliferation and apoptosis were evaluated by Cell Counting Kit-8 (CCK-8) assay and Annexin-V staining, respectively. In addition, the apoptosis and autophagy of the markers were detected by Western blotting.

RESULTS

Patients expressing high AK5 levels in the tumor tissues had significantly shorter survival compared to low-expressing group. In addition, AK5 expression was associated with T stage and N stage and was an independent prognostic factor. AK5 knockdown in the AZ521 and MKN74 cells significantly inhibited proliferation and autophagy, and increased apoptosis.

CONCLUSIONS

AK5 is a potential prognostic marker and therapeutic target for GC.

Continuous Anaerobic Digestion of Wood Vinegar Wastewater From Pyrolysis: Microbial Diversity and Functional Genes Prediction

Wood vinegar wastewater (WVWW) is the main by-product of biomass pyrolysis process, which is more suitable to use anaerobic digestion (AD) to achieve energy recovery due to its large amount of organic matter. In this study, the up-flow anaerobic sludge bed (UASB) reactor was used to investigate the continuous anaerobic transformation of WVWW with gradient concentrations (0.3, 0.675, 1, 2, 3, 4, 5, 6, and 7 g COD/L). Then, the changes of microbial community, diversity index and functional gene were analyzed in detail. The results revealed that WVWW showed good AD performance in continuous fermentation. WVWW of organic loading rate (OLR) of >8.58 g COD/L⋅d showed severe inhibition on biodegradability and methane production, which is mainly due to the toxic substances as compared with the control group. The bacterial communities were dominated by phyla of Chloroflexi, Firmicutes, Proteobacteria, Acidobacteria, Synergistetes, and Actinobacteria. The gene abundances related to energy production, carbohydrate transport and metabolism were relatively high, which are mainly responsible for carbon forms conversion and carbohydrate degradation. This study will provide a basis for the screening and enrichment of functional bacteria and genes.

Acidogenic and methanogenic properties of corn straw silage: Regulation and microbial analysis of two-phase anaerobic digestion

Corn straw silage (CSS) is one of the organic solid residues available for biogas production. The aim of this study was to investigate the possibility and optimal controlling strategy for anaerobic digestion (AD) of CSS. Four leaching bed reactors (LBR) were operated at different pH. Maximum volatile fatty acids (VFAs) concentration of 19.34 g/L was reached at pH 8.0 with acetic and propionic acids as dominant VFAs. The subsequent microbial analysis indicated that abundant bacteria were Firmicutes, Bacteroidetes and Proteobacteria. UASB as methanogenic reactor was integrated with the LBR. The organic loading rate (OLR) could reach 8 g COD/L·d with effective conversion of VFAs. Acetotrophic Methanosaeta and hydrogenotrophic Methanobacterium played major roles in methanogenic process. In the whole process, the results showed that methane yield of 143.4 mL CH₄/g volatile solid (VS) was obtained. pH and OLR controls in two-phase AD were feasible for methane production from CSS.

Enhancing the anaerobic digestion of corn stover by chemical pretreatment with the black liquor from the paper industry

In this work, black liquor as a waste from paper industry was used to pretreat corn stover before anaerobic digestion. The batch mode anaerobic digestion achieved a methane production up to 260.5 mL/g VS when the corn stover was pretreated the black liquor of 12 g NaOH/L alkalinity for 24 h, which was 59.1% higher than the control. In the semi-continuous mode anaerobic digestion, black liquor pretreatment increased the buffering capacity of the digestate to maintain suitable pH and total VFA/alkalinity ratio with no adverse effect resulted from the presence of ions. The structural and chemical changes of corn stover after the pretreatment were investigated to rationalize the enhanced performance of anaerobic digestion.

The role of cyanide-resistant respiration in Solanum tuberosum L. against high light stress

Cyanide-resistant respiration in potato mitochondria is an important pathway for energy dissipation. It can be activated by high light; however, it is unclear what roles cyanide-resistant respiration plays in the response to high light stress in potato. We designed a CRISPR vector for the functional gene StAOX of the potato cyanide-resistant respiratory pathway. Agrobacterium tumefaciens GV3101 was transformed into potato. Hydrogen peroxide level, MDA content, antioxidant activity and cyanide-resistant respiratory capacity of potato leaves under high light stress were determined. Photosynthetic efficiency and chlorophyll content were determined. In addition, the operation of the malate-oxaloacetate shuttle route and transcription level of photorespiration-related enzymes were also examined. The results showed that two base substitutions occurred at the sequencing target site on leaves of the transformed potato. Accumulation of ROS and increased membrane lipid peroxidation were detected in the transformed potato leaves and lower photosynthetic efficiency was observed. The transcription level of the malate-oxaloacetate shuttle route and photorespiration-related enzymes also significantly increased. These results indicate that the cyanide-resistant respiration is an important physiological pathway in potato in response to high light stress. It also suggests that plant cyanide-resistant respiration is closely related to photosynthesis. This implies the unexplored importance of plant cyanide-resistant respiration in plant photosynthesis, energy conversion and carbon skeleton formation.

Two-phase anaerobic digestion of lignocellulosic hydrolysate: Focusing on the acidification with different inoculum to substrate ratios and inoculum sources

Biogas production from lignocellulosic hydrolysate is of great potential for lignocellulosic materials. Two-phase anaerobic digestion was proposed in this study. Acidogenic fermentation was carried out with corn straw hydrolysate as feedstock for volatile fatty acids (VFAs) production. Using anaerobic sludge (AnS), different inoculum to substrate ratios (ISRs) of 0.5:1, 1:1 and 2:1 were investigated. The highest VFAs yield was obtained at ISR of 0.5:1.VFAs composition analysis showed that butyric acid was the predominant acid, followed by acetic acid and propionic acid. The effects of AnS and aerobic sludge (AeS) on the acidogenic performance of hydrolysate were compared. The optimum VFA yields were 0.38 g/g COD-added for AnS and 0.32 g/g COD-added for AeS with HRT of 5 d, respectively. The bacterial diversities of inocula and digestates were analyzed by high-throughput sequencing. Two origins of inocula had distinct bacterial structures, but they did share core communities that included Firmicutes, Chloroflexi, Proteobacteria and Bacteroidetes at phylum level. The bacterial communities of both digestates changed significantly as compared with those in inoculum. Firmicutes was absolutely dominant in all the bacterial species. Therefore, the AeS could be an option as the acidogenic inoculum. The microbial information will be beneficial for the enrichment and acclimatization of microbes. In methanogenic process, VFAs obtained in acidogenic stage could be efficiently converted into methane. The ultimate methane yield at organic loading rate (OLR) of 8 g/L·d could reach 290 mL CH₄/g COD-added and 279 mL CH₄/g COD-added for AnS and AeS acidified digestate. Two-phase anaerobic digestion was proved to be suitable for bioconversion of lignocellulosic hydrolysate into biogas.

Methane production from the anaerobic digestion of substrates from corn stover: Differences between the stem bark, stem pith, and leaves

This work evaluated the methane potential and methane production rate of the stem bark (SB), stem pith (SP), and leaves (LV) of corn stover from batch anaerobic digestion. The obtained cumulative methane potential and the hydrolysis kinetics constant were 0.201, 0.214, and 0.199 L g^-1 VS (volatile solids) and 0.090, 0.149, and 0.227 d^-1 for SB, SP, and LV, respectively. The chemical composition and the crystalline structure of the substrates as well as their changes during the anaerobic digestion were inspected, and their impacts on the characteristics of methane production were assessed. The methane production rate correlated positively with the hemicellulose and soluble compounds content and negatively with the cellulose and lignin content, but the degradation rates of hemicellulose and cellulose in the specific substrate were complex and comparable. The methane production has limit correlation with the crystalline structure of the substrates. Microbial community structure was analyzed to elucidate functional microorganism contributing to methane production of different substrate. The abundance of Bacteroidetes and Firmicutes was most affected by the substrate, and positively related to methane yields.

Compound climate events transform electrical power shortfall risk in the Pacific Northwest

Power system reliability is sensitive to climate-driven variations in both energy demand and water availability, yet the combined effect of these impacts is rarely evaluated. Here we show that combined climate change impacts on loads and hydropower generation may have a transformative effect on the nature and seasonality of power shortfall risk in the U.S. Pacific Northwest. Under climate change, potential shortfall events occur more readily, but are significantly less severe in nature. A seasonal reversal in shortfall risk occurs: winter shortfalls are eradicated due to reduced building heating demands, while summer shortfalls multiply as increased peak loads for day-time cooling coincide with impaired hydropower generation. Many of these summer shortfalls go unregistered when climate change impacts on loads and hydropower dispatch are analyzed in isolation-highlighting an important role of compound events.

Comparative proteomic analyses of Hyphozyma roseonigra ATCC 20624 in response to sclareol

Sclareol is an important intermediate for ambroxide synthesis industries. Hyphozyma roseonigra ATCC 20624 was the only reported strain capable of degrading sclareol to the main product of sclareol glycol, which is the precursor of ambroxide. To date, knowledge is lacking about the effects of sclareol on cells and the proteins involved in sclareol metabolism. Comparative proteomic analyses were conducted on the strain H. roseonigra ATCC 20624 by using sclareol or glucose as the sole carbon source. A total of 79 up-regulated protein spots with a >2.0-fold difference in abundance on 2-D gels under sclareol stress conditions were collected for further identification. Seventy spots were successfully identified and finally integrated into 30 proteins. The up-regulated proteins under sclareol stress are involved in carbon metabolism; and nitrogen metabolism; and replication, transcription, and translation processes. Eighteen up-regulated spots were identified as aldehyde dehydrogenases, which indicating that aldehyde dehydrogenases might play an important role in sclareol metabolism. Overall, this study may lay the fundamentals for further cell engineering to improve sclareol glycol production.

Microbial and nutritional regulation of high-solids anaerobic mono-digestion of fruit and vegetable wastes

The anaerobic digestion of single fruit and vegetable wastes (FVW) can be easily interrupted by rapid acidogenesis and inhibition of methanogen, and the digestion system tends to be particularly unstable at high solid content. In this study, the anaerobic digestion of FVW in batch experiments under mesophilic condition at a high solid concentration of 10% was successfully conducted to overcome the acidogenesis problem through several modifications. Firstly, compared with the conventional anaerobic sludge (CAS), the acclimated anaerobic granular sludge (AGS) was found to be a better inoculum due to its higher Archaea abundance. Secondly, waste activated sludge (WAS) was chosen to co-digest with FVW, because WAS had abundant proteins that could generate intermediate ammonium. The ammonium could neutralize the accumulated volatile fatty acids (VFAs) and prevent the pH value of the digestion system from rapidly decreasing. Co-digestion of FVW and WAS with TS ratio of 60:40 gave the highest biogas yield of 562 mL/g-VS and the highest methane yield of 362 mL/g-VS. Key parameters in the digestion process, including VFAs concentration, pH, enzyme activity, and microbial activity, were also examined.

Fluorescence Enhancement of Terminal Amine Assembled on Gold Nanoclusters and Its Application to Ratiometric Lysine Detection

Ratiometric fluorescent sensors have emerged as an attractive tool for analytical sensing and optical imaging due to their providing a built-in self-calibration for environmental effects. However, cumbersome processes of nanoparticles modified with fluorophores for constructing traditional ratiometric sensors limit their further application. Herein, we report a facile and label-free strategy for constructing a ratiometric sensor based on an aggregation-induced-emission (AIE)-active amine-terminated small molecule on the surface of gold nanoclusters (AuNCs). Intrinsic fluorescence of the terminal primary amine of the small molecule lysine resulting from AIE was first observed in the presence of glutathione-stabilized gold nanoclusters (GSH-AuNCs). Using lysine as both the fluorophore and the analyte, the synthesized GSH-AuNCs showed a good lysine-responsive ratiometric property. The AIE-active dual-emitting fluorescence property of the GSH-AuNCs/lysine complex made it feasible to achieve ratiometrically detection of the analyte without conjugated fluorogen. This AIE-active GSH-AuNC-based biosensor possesses high selectivity, rapid response, and excellent photostability. Moreover, the strategy opens a new pathway for the construction of a label-free ratiometric fluorescent sensor with various applications.

Enhanced methane production by semi-continuous mesophilic co-digestion of potato waste and cabbage waste: Performance and microbial characteristics analysis

Anaerobic granular sludge was used as an inoculum for co-digestion of potato waste (PW) and cabbage waste (CW) in batch and semi-continuous modes at 37±1°C for enhanced methane generation. Batch test results indicated that an equal proportion (1:1) by volatile solid was the optimal mixing ratio for co-digestion of PW and CW. Semi-continuous co-digestion process results showed that the stepwise increasing of the organic loading rates from 1.0 to 5.0kgVS/m³·d improved the methane yield from 224 to 360mL/g-VS. And the highest value was respectively 18.4% and 24.1% higher as compared to the mon-digestion of PW and CW. Further investigation with high-throughput sequencing analysis revealed that the enhanced methane generation was attributed to the partial shift from archaeal Methanosaeta to Methanosarcina and Methanobacterium, and from bacterial Firmicutes to Bacteroidetes and Proteobacteria. The volatile fatty acids concentration accounted for the modification of microbial communities.

[Prognostic significance of tumor deposits in patients with stage Ⅲ colon cancer]

Objective: To investigate the prognostic significance of tumor deposits (TD) in patients with stage Ⅲ colorectal cancer who underwent radical resection. Methods: We retrospectively analyzed the clinicopathological data, and the impact of tumor deposits on the disease free survival (DFS) and overall survival (OS) in 206 patients with stage Ⅲ colorectal cancer using Kaplan-Meier and Cox regression analyses. Results: Among the 206 patients with stage Ⅲ colorectal cancer, there were 112 (54.4%) tumor deposit-positive (TD⁺ ) cases and 94 (45.6%) tumor deposit-negative (TD^-) cases. The TD^- and TD⁺ cases accounted for 10.6% and 21.4% of patients aged <50 years, 22.3% and 36.6% of patients with poorly differentiated carcinoma, and 16% and 29.5% of patients with neural invasion, respectively (P<0.05 for all). In addition, the neural invasion was more often found along with the increasing number of TD. However, multivariate analysis showed that TD was not significantly associated with DFS and OS of the patients. Among the patients with N1 stage cancer, the 3-year DFS rates of TD⁺ and TD^- groups were 23.0% and 58.8%, and the median disease-free survival durations were 26 months and 43 months, respectively (P=0.002). Meanwhile, in the TD^- group, the 3-year DFS rates in the patients with stage N1a~1b without tumor deposit and N1c cancer were 63.5% and 21.2%, and the median disease-free survival durations were 41 and 25 months, respectively (P=0.004). Conclusions: Tumor deposit is an independent unfavorable prognostic factor affecting the DFS. The number of tumor deposits may be an important factor affecting prognosis in stage Ⅲ colorectal cancer patients. Tumor deposits after radical resection are associated with neural invasion, and can be used as an independent factor of poor prognostic evaluation in patients with stage N1 colorectal cancer.

Expression features of CXCR5 and its ligand, CXCL13 associated with poor prognosis of advanced colorectal cancer

OBJECTIVE

CXCL13 plays a unique role in the trafficking and homing of B1 cells associated with its cognate receptor, CXCR5. The CXCR5-CXCL13 axis has been previously demonstrated to be a poor prognosis factor in malignancies. However, the clinical significance of the CXCR5-CXCL13 expression in colorectal cancer carcinoma (CRC) remains unclear. The aim of this study was to investigate the CXCR5-CXCL13 expression in CRC and determine its correlation with the progression and prognosis of the tumor.

PATIENTS AND METHODS

A total of 144 paraffin-embedded specimens with advanced colon cancer were assessed for CXCR5 and CXCL13 by immunohistochemistry. Patients' long-term survival was also monitored. There were significant differences in lymph node metastasis (p = 0.0066), neural invasion (p = 0.0061) and neural invasion (p = 0.0001) between high and low expression of CXCR5.

RESULTS

There were significant differences in distant metastasis (p = 0.0261), TNM stage (p = 0.0409), differentiation (p < 0.0001) and neural invasion of the CXCL13. Both CXCR5 and CXCL13 was associated with poor correlation with the overall survival (OS) and relapse-free survival (RFS).

CONCLUSIONS

Our data suggest that the CXCR5 and CXCL13 may play a crucial role in the development, metastasis and relapse of advanced colon cancer. They can be used as prognostic markers of colon cancer in clinical practice.

Characterization of two Streptomyces enzymes that convert ferulic acid to vanillin

Production of flavors from natural substrates by microbial transformation has become a growing and expanding field of study over the past decades. Vanillin, a major component of vanilla flavor, is a principal flavoring compound used worldwide. Streptomyces sp. strain V-1 is known to be one of the most promising microbial producers of natural vanillin from ferulic acid. Although identification of the microbial genes involved in the biotransformation of ferulic acid to vanillin has been previously reported, purification and detailed characterization of the corresponding enzymes with important functions have rarely been studied. In this study, we isolated and identified 2 critical genes, fcs and ech, encoding feruloyl-CoA synthetase and enoyl-CoA hydratase/aldolase, respectively, which are involved in the vanillin production from ferulic acid. Both genes were heterologously expressed in Escherichia coli, and the resting cell reactions for converting ferulic acid to vanillin were performed. The corresponding crucial enzymes, Fcs and Ech, were purified for the first time and the enzymatic activity of each purified protein was studied. Furthermore, Fcs was comprehensively characterized, at an optimal pH of 7.0 and temperature of 30°C. Kinetic constants for Fcs revealed the apparent K_m, k_cat, and V_max values to be 0.35 mM, 67.7 s⁻¹, and 78.2 U mg⁻¹, respectively. The catalytic efficiency (k_cat/K_m) value of Fcs was 193.4 mM⁻¹ s⁻¹ for ferulic acid. The characterization of Fcs and Ech may be helpful for further research in the field of enzymatic engineering and metabolic regulation.

Production of (2S,3S)-2,3-butanediol and (3S)-acetoin from glucose using resting cells of Klebsiella pneumonia and Bacillus subtilis

Production of highly pure (2S,3S)-2,3-butanediol ((2S,3S)-2,3-BD) and (3S)-acetoin ((3S)-AC) in high concentrations is desirable but difficult to achieve. In the present study, glucose was first transformed to a mixture of (2S,3S)-2,3-BD and meso-2,3-BD by resting cells of Klebsiella pneumoniae CICC 10011, followed by biocatalytic resolution of the mixture by resting cells of Bacillus subtilis 168. meso-2,3-BD was transformed to (3S)-AC, leaving (2S,3S)-2,3-BD in the reaction medium. Using this approach, 12.5 g l(-1) (2S,3S)-2,3-BD and 56.7 g l(-1) (3S)-AC were produced. Stereoisomeric purity of (2S,3S)-2,3-BD and enantiomeric excess of (3S)-AC was 96.9 and 96.2%, respectively.

Efficient production of L-lactic acid from corncob molasses, a waste by-product in xylitol production, by a newly isolated xylose utilizing Bacillus sp. strain

Lignocellulosic biomass-derived sugars are considered nowadays to be an economically attractive carbohydrate feedstock for large-scale fermentations of bulk chemicals such as lactic acid. In the present study, corncob molasses containing a high content of xylose, which is one of the lignocellulosic biomasses and a waste by-product from xylitol production, was used for L-lactic acid production via a newly isolated xylose utilizing Bacillus sp. strain XZL9. Bacillus sp. strain XZL9 can utilize the mixture of sugars including xylose, arabinose, and glucose in corncob molasses for L-lactic acid production. High concentration of L-lactic acid (74.7 g l⁻¹) was obtained from corncob molasses (initial total sugars of 91.4 g l⁻¹) in fed-batch fermentation. This study provides an encouraging means of producing L-lactic acid from lignocellulosic resource such as the low-cost corncob molasses.

Kinetics of D-lactic acid production by Sporolactobacillus sp. strain CASD using repeated batch fermentation

D-lactic acid was produced by Sporolactobacillus sp. strain CASD in repeated batch fermentation with one- and two-reactor systems. The strain showed relatively high energy consumption in its growth-related metabolism in comparison with other lactic acid producers. When the fermentation was repeated with 10% (v/v) of previous culture to start a new batch, D-lactic acid production shifted from being cell-maintenance-dependent to cell-growth-dependent. In comparison with the one-reactor system, D-lactic acid production increased approximately 9% in the fourth batch of the two-reactor system. Strain CASD is an efficient D-lactic acid producer with increased growth rate at the early stage of repeated cycles, which explains the strain's physiological adaptation to repeated batch culture and improved performance in the two-reactor fermentation system. From a kinetic point of view, two-reactor fermentation system was shown to be an alternative for conventional one-reactor repeated batch operation.

The patterns of care studies for operable breast cancer in China

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Background: To present the results of clinical practices for operable breast cancer (BC) in the developed areas of China during the past decade. Methods: Four academic levels of radiotherapy (RT) departments, located in the Southeast coast of China, were selected. A pattern of care study, about women with operated BC and post-operative RT during 1999 and 2006, was conducted. The recruited samples were evaluated for their medical files completeness at first. For qualified documentations, data collected included patient characteristics, clinical and pathologic features, and treatment course received. Frequencies and corresponding percentages were calculated and analyzed for comparisons between 1999 and 2006. Results: 97 in 1999 and 271 in 2006 were identified as qualified files. Patient's diagnosis median age were 48 (1996) and 46 (2006) years. The clinical staging with I, II, and III (UICC 1997) were in 11%, 69%, 13% of 1999 patients and 15%, 74%, 7% of the 2006. The pathological characteristics were clearly defined in 78% (1999) and 84% (2006), but hormonal receptors and Her2neu were performed in 59% and 0% in the 1999 vs. 73% (p < 0.05) and 1% in 2006 survey. As type and extent of surgery and RT, the percentage of conservative treatment was increased from 4% in 1999 to 12% in 2006 (p< 0.05), postmastectomy RT was done for all the others. The time interval from operation to initiation of RT were longer in 2006, the mean was delayed from 23.8 to 43.4 days. The axillary operation pattern including lymph node dissection, level I/II dissection, and sentinel lymph node biopsy (SLNB), were documented in 61%, 24%, and 8% of patients in 2006. For patients of 1999, no SLNB was performed and 16% with level I/II operation (p< 0.05). Systemic chemotherapy (CT) and/or hormonal therapy were used in 74% (1999) and 98% (2006) of patients respectively (p< 0.05). Anthracyclines and paclitaxel-based CT regimens use significantly increased between 1999 and 2006 (31% vs. 52% and 12% vs. 36%). Conclusions: The practice patterns established in this study provide a baseline data. The present results demonstrate a low level of compliance with Western guidelines of clinical practices with current BC standards and continued improvement in many categories. Establishment and widespread use of international guidelines in China are desirable.

No significant financial relationships to disclose.