High-sensitivity fiber-tip acoustic sensor with ultrathin gold diaphragm.

Miniature acoustic sensors with high sensitivity are highly desired for applications in medical photoacoustic imaging, acoustic communications and industrial nondestructive testing. However, conventional acoustic sensors based on piezoelectric, piezoresistive and capacitive detectors usually require a large element size on a millimeter to centimeter scale to achieve a high sensitivity, greatly limiting their spatial resolution and the application in space-confined sensing scenarios. Herein, by using single-crystal two-dimensional gold flakes (2DGFs) as the sensing diaphragm of an extrinsic Fabry-Perot interferometer on a fiber tip, we demonstrate a miniature optical acoustic sensor with high sensitivity. Benefiting from the ultrathin thickness (∼8 nm) and high reflectivity of the 2DGF, the fiber-tip acoustic sensor gives an acoustic pressure sensitivity of ∼300 mV/Pa in the frequency range from 100 Hz to 20 kHz. The noise-equivalent pressure of the fiber-tip acoustic sensor at the frequency of 13 kHz is as low as 62.8 µPa/Hz1/2, which is one or two orders of magnitude lower than that of reported optical acoustic sensors with the same size.

Zearalenone degrading enzyme evolution to increase the hydrolysis efficiency under acidic conditions by the rational design.

Based on rational design, zearalenone degrading enzyme was evolved to improve the hydrolysis efficiency under acidic conditions. At pH 4.2 and 37 °C, the activity of the zearalenone degrading enzyme evolved with 8 mutation sites increased from 7.69 U/mg to 38.67 U/mg. Km of the evolved zearalenone degrading enzyme decreased from 283.61 µM to 75.33 µM. The evolved zearalenone degrading enzyme was found to effectively degrade zearalenone in pig stomach chyme. Molecular docking revealed an increase in the number of hydrogen bonds and π-sigma interactions between the evolved zearalenone degrading enzyme and zearalenone. The evolved zearalenone degrading enzyme was valuable for hydrolyzing zearalenone under acidic conditions.

[Meta-analysis and trial sequential analysis of Tanreqing Injection in treatment of severe pneumonia in elderly].

This study aimed to systematically evaluate the effectiveness and safety of Tanreqing Injection in the treatment of severe pneumonia in the elderly. Eighteen randomized controlled trials(RCTs) involving 1 457 elderly patients with severe pneumonia were included in the study after conducting searches in both Chinese and English databases as well as clinical trial registration platforms. The quality of the included studies was assessed using the Cochrane risk of bias assessment tool. Meta-analysis were conducted using RevMan 5.4 and Stata 17 software, and trial sequential analysis(TSA) was performed using TSA 0.9.5.10 beta software. Meta-analysis results showed that compared with conventional western medicine treatment, Tanreqing Injection + conventional western medical significantly improved the clinical effectiveness in elderly patients with severe pneumonia(RR=1.26, 95%CI[1.20, 1.32], P<0.000 01), arterial oxygen partial pressure(SMD=6.23, 95%CI[3.29, 9.18], P<0.000 1), oxygenation index(SMD=11.72, 95%CI[4.41, 19.04], P=0.002), reduce procalcitonin(SMD=-6.16, 95%CI[-8.10,-4.21], P<0.000 01), C-reactive protein(SMD=-8.50, 95%CI[-11.05,-5.96], P<0.000 01), white blood cell count(SMD=-4.56, 95%CI[-5.73,-3.39], P<0.000 01), and shortened the duration of fever(SMD=-3.12, 95%CI[-4.61,-1.63], P<0.000 1), cough(SMD=-4.84, 95%CI[-6.90,-2.79], P<0.000 01), lung rales(SMD=-0.99, 95%CI[-1.54,-0.44], P=0.000 4), and mechanical ventilation time(SMD=-3.26, 95%CI[-5.03,-1.50], P=0.000 3), increase CD4~+ T-cell levels(SMD=6.73, 95%CI[5.23, 8.23], P<0.000 01) and CD8~+ T-cell levels(SMD=7.47, 95% CI[5.32, 9.61], P<0.000 01) with no significant adverse reactions. TSA confirmed the stability and reliability of the results related to clinical effectiveness. This study suggests that Tanreqing Injection, as a Chinese medicinal preparation, has a significant therapeutic effect and good safety profile in the treatment of severe pneumonia in elderly patients. Due to the limited quality of the included studies, high-quality RCT is still needed to provide evidence support for the above conclusions.

Production of acetic acid from wheat bran by catalysis of an acetoxylan esterase.

In this study, a gene encoding for acetylxylan esterase was cloned and expressed in E. coli. A single uniform band with molecular weight of 31.2 kDa was observed in SDS-PAGE electrophoresis. Served as the substrate, p-nitrophenol butyrate was employed to detect the recombinant enzyme activity. It exhibited activity at a wide temperature range (30-100 °C) and pH (5.0-9.0) with the optimal temperature of 70 °C and pH 8.0. Acetylxylan esterase showed two substrates' specificities with the highest Vmax of 177.2 U/mg and Km of 20.98 mM against p-nitrophenol butyrate. Meanwhile, the Vmax of p-nitrophenol acetate was 137.0 U/mg and Km 12.16 mM. The acetic acid yield of 0.39 g/g was obtained (70 °C and pH 8.0) from wheat bran pretreated using amylase and papain. This study showed the highest yield up to date and developed a promising strategy for acetic acid production using wheat bran.

Ferulic acid production from wheat bran by integration of enzymatic pretreatment and a cold-adapted carboxylesterase catalysis.

High-value chemical production from natural lignocellulose transformation is a reliable waste utilization approach. A gene encoding cold-adapted carboxylesterase in Arthrobacter soli Em07 was identified. The gene was cloned and expressed in Escherichia coli to obtain a carboxylesterase enzyme with a molecular weight of 37.2 KDa. The activity of the enzyme was determined using α-naphthyl acetate as substrate. Results showed that the optimum enzyme activity of carboxylesterase was at 10 °C and pH 7.0. It was also found that the enzyme could degrade 20 mg enzymatic pretreated de-starched wheat bran (DSWB) to produce 235.8 µg of ferulic acid under the same conditions, which was 5.6 times more than the control. Compared to the chemical strategy, enzymatic pretreatment is advantageous because it is environmentally friendly, and the by-products can be easily treated. Therefore, this strategy provides an effective method for high-value utilization of biomass waste in agriculture and industry.

Genetic engineering for biohydrogen production from microalgae.

The development of biohydrogen as an alternative energy source has had great economic and environmental benefits. Hydrogen production from microalgae is considered a clean and sustainable energy production method that can both alleviate fuel shortages and recycle waste. Although algal hydrogen production has low energy consumption and requires only simple pretreatment, it has not been commercialized because of low product yields. To increase microalgal biohydrogen production several technologies have been developed, although they struggle with the oxygen sensitivity of the hydrogenases responsible for hydrogen production and the complexity of the metabolic network. In this review, several genetic and metabolic engineering studies on enhancing microalgal biohydrogen production are discussed, and the economic feasibility and future direction of microalgal biohydrogen commercialization are also proposed.

Concurrent production of ferulic acid and glucose from wheat bran by catalysis of a putative bifunctional enzyme.

The aim of this work is to study a bifunctional endoglucanase/carboxylesterase in Sphingobacterium soilsilvae Em02 and express it in soluble form in engineered Escherichia coli. The molecular weight of the recombinant protein of the bifunctional enzyme was 41 KDa. This research also determined the enzymatic activities of the bifunctional enzymes using microcrystalline cellulose and p-nitrophenyl butyrate as substrates and found 40 °C as the optimum temperature for their enzymatic activities. The optimal pH in dual function was 6.0 for endoglucanase and 7.0 for carboxylesterase. The bifunctional enzyme also exhibited enzymatic activities on the natural biomass by generating up to 3.94 mg of glucose and 49.4 µg of ferulic acid from 20 mg of destarched wheat bran. This indicates the broad application prospects of the bifunctional enzyme in agriculture and industry.

Genetic manipulation strategies for ethanol production from bioconversion of lignocellulose waste.

Lignocellulose waste was served as promising raw material for bioethanol production. Bioethanol was considered to be a potential alternative energy to take the place of fossil fuels. Lignocellulosic biomass synthesized by plants is regenerative, sufficient and cheap source for bioethanol production. The biotransformation of lignocellulose could exhibit dual significance-reduction of pollution and obtaining of energy. Some strategies are being developing and increasing the utilization of lignocellulose waste to produce ethanol. New technology of bioethanol production from natural lignocellulosic biomass is required. In this paper, the progress in genetic manipulation strategies including gene editing and synthetic genomics for the transformation from lignocellulose to ethanol was reviewed. At last, the application prospect of bioethanol was introduced.

Stereoselective Synthesis of the Core Structures of Pyrrocidines and Wortmannines through the Excited-State Nazarov Reactions.

The reaction conditions and scope of the excited-state Nazarov reaction of dicyclicvinyl ketones were studied. The stereochemistry of this electrocyclization is consistent with the mechanism of the pericyclic reaction and Woodward-Hoffmann rule. UV-light-promoted excited-state Nazarov reactions gave hydrofluorenones bearing a syn-cis configuration via a disrotatory cyclization. The core tricyclic hydrofluorenones of pyrrocidines and wortmannines were constructed via the excited-state Nazarov reactions, which demonstrated their synthetic potential in complex natural product total synthesis.

Functional Analysis of a Glutamine Biosynthesis Protein from a Psychrotrophic Bacterium, Cryobacterium soli GCJ02.

A putative glutamine synthetase (GS) was detected in a psychrophilic bacterium, Cryobacterium soli GCJ02. For gaining greater insight into its functioning, the gene was cloned and expressed in a heterologous host, Escherichia coli. The monomer enzyme with a molecular weight of 53.03 kDa was expressed primarily in cytosolic compartment. The enzyme activity was detected using glutamate and ATP. The optimum conditions of its biosynthesis were observed to be 60 °C and pH value 7.5. Its thermostability was relatively high with a half-life of 50 min at 40 °C. GS activity was enhanced in the presence of metal ions such as Mg2+ and Mn2+, whereas Fe2+, Cu2+ and Ca2+ proved inhibitory. The consensus pattern [EXE]-D-KP-[XGXGXH] in the GS lies between residues 132 and 272. The catalytic active sites consisting of EAE and NGSGMH were verified by site-directed mutagenesis. Based on the analysis of the consensus pattern, the GS/glutamate synthase cycle of C. soli GCJ02 is expected to contribute to the GS synthesic activity.

Green Synthesis of the Flavor Esters with a Marine Candida parapsilosis Esterase Expressed in Saccharomyces cerevisiae.

The green synthesis of the flavor esters, n-propyl acetate, isobutyl acetate and isoamyl acetate had the advantages over the chemical synthesis. The esterase from Candida parapsilosis could transform n-propanol, isobutanol and isoamyl alcohol into n-propyl acetate, isobutyl acetate and isoamyl acetate, respectively. The esterase was expressed in Saccharomyces cerevisiae. At 30 °C for 1 d, the concentration of n-propyl acetate, isobutyl acetate and isoamyl acetate synthesized by the esterase expressed in Saccharomyces cerevisiae was 24.6 mg/100 mL, 8.3 mg/100 mL, 5.6 mg/100 mL, respectively. Expression of the esterase has a practical significance for flavor ester synthesis by green biochemical process.

Tandem integration of aerobic fungal cellulase production, lignocellulose substrate saccharification and anaerobic ethanol fermentation by a modified gas lift bioreactor.

Cellulase production, lignocellulose saccharification and bioethanol fermentation were integrated to efficiently produce bioethanol. A modified gas lift bioreactor was developed for bioethanol production by the integrated process. Cellulase production was achieved using Aspergillus niger mycelia immobilized within the reactor in wire meshes, and Saccharomyces cerevisiae cells were immobilized in resin beads. During four repeated batches fermentation, cellulase activities were more than 6.28 U/mL and bioethanol production was over 45.9 g/L for 48 h. The factual bioethanol conversion efficiency was 86.8%. By the modification of the modified gas lift bioreactor, immobilization of Aspergillus niger mycelia and Saccharomyces cerevisiae cells, aerobic cellulase production, substrate saccharification and anaerobic bioethanol fermentation were successfully integrated in tandem. The integrated processes is of great significance in bioethanol production.

Cryobacterium soli sp. nov., isolated from forest soil.

A taxonomic study was performed on strain GCJ02T, which was isolated from forest soil from Baishan City, PR China. The bacterium was Gram-stain-positive, catalase-positive and weakly oxidase-positive, rod-shaped and non-motile. Growth was observed at salinities of 0-6.0 % and at temperatures of 4-26 °C. Phylogenetic analysis based on 16S rRNA gene sequences indicated that GCJ02T represented a member of the genus Cryobacterium, with the highest sequence similarity to Cryobacterium arcticum SK1T (99.5 %) and Cryobacterium zongtaii TMN-42T (99.5 %), followed by Cryobacterium psychrotolerans CGMCC 1.5382T (97.7 %), and other species of the genus Cryobacterium (96.4-96.9 %). The ANI and the DNA-DNA hybridization estimate values between GCJ02T and all type strains of species of the genus Cryobacterium were 72.5-84.5 % and 19.6-28.7 %, respectively. The principal fatty acids (>10 %) of GCJ02T were anteiso-C15 : 0(53.0 %) and anteiso-C17 : 0 (18.8 %). The G+C content of the chromosomal DNA was 68.4 mol%. The respiratory quinone was determined to be MK-10. Phosphatidylglycerol, diphosphatidylglycerol, glycolipid, and one unidentified phospholipid and three unidentified polar lipid were present. The combined genotypic and phenotypic data indicated that strain GCJ02T represents a novel species within the genus Cryobacterium, for which the name Cryobacterium soli sp. nov. is proposed, with the type strain GCJ02T (=MCCC 1K03549T=JCM 32391T).

Full recycling of citric acid wastewater through anaerobic digestion, air-stripping and pH control.

Anaerobic digestion effluent (ADE) from the anaerobic digestion treatment of citric acid wastewater can be reused as a potential substitute for process water in the citric acid fermentation. However, excessive sodium contained in ADE significantly decreases citric acid production. In this paper, the inhibition mechanism of sodium on citric acid fermentation was investigated. We demonstrated that excessive sodium did not increase oxidative stress for Aspergillus niger, but reduced the pH of the medium significantly over the period 4-24 h, which led to lower activities of glucoamylase and isomaltase secreted by A. niger, with a decrease of available sugar concentration and citric acid production. ADE was pretreated by air-stripping prior to recycle and 18 g/L calcium carbonate was added at the start of fermentation to control the pH of the medium. The inhibition caused by ADE was completely alleviated and citric acid production substantially increased from 118.6 g/L to 141.4 g/L, comparable to the fermentation with deionized water (141.2 g/L). This novel process could decrease wastewater discharges and fresh water consumption in the citric acid industry, with benefit to the environment.

Rapid analysis of the Tanreqing injection by near-infrared spectroscopy combined with least squares support vector machine and Gaussian process modeling techniques.

Near-infrared spectroscopy (NIRS) combined with chemometrics was used to analyze the main active ingredients including chlorogenic acid, caffeic acid, luteoloside, baicalin, ursodesoxycholic acid, and chenodeoxycholic acid in the Tanreqing injection. In this paper, first, two hundred samples collected in the product line were divided into the calibration set and prediction set, and the reference values were determined by the High Performance Liquid Chromatography- Diode Array Detector/Evaporative Light Scattering Detector (HPLC-DAD/ELSD) method. Partial least squares (PLS) analysis was implemented as a linear method for models calibrated with different preprocessing means. Wavelet transformation (WT) was introduced as a variable selection technique by means of multiscale decomposition, and wavelet coefficients were employed as the input for modeling. Furthermore, two nonlinear approaches, least squares support vector machine (LS-SVM) and Gaussian process (GP), were applied to exploit the complicated relationship between the spectra and active ingredients. The optimal models for each ingredient were obtained by LS-SVM and GP methods. The performance of the final models was evaluated by the root mean square error of calibration (RMSEC), root mean square error of cross-validation (RMSECV), root mean square error of prediction (RMSEP) and correlation coefficient (R). All of the models in the paper give a good calibration ability with an R value above 0.92, and the prediction ability is also satisfactory, with an R value higher than 0.85. The overall results demonstrate that nonlinear models are more stable and predictable than linear ones, and they will be more suitable for the CHM system when high accuracy analysis is required. It can be concluded that NIRS with the LS-SVM and GP modeling methods is promising for the implementation of process analytical technology (PAT) in the pharmaceutical industry of Chinese herbal injections (CHIs).

Correction to: Increasing of activity and thermostability of cold active butanol-tolerant endoglucanase from a marine Rhodococcus sp. under high concentrations of butanol condition.

[This corrects the article DOI: 10.1007/s13205-018-1249-4.].

Increasing of activity and thermostability of cold active butanol-tolerant endoglucanase from a marine Rhodococcus sp. under high concentrations of butanol condition.

Optimum pH and temperature of the endoglucanase from Rhodococcus sp. was 5.0 and 40 °C. The endoglcuanase activity was 1.18 folds higher in 5% butanol solution than that in butanol-free solution. Melt point temperature was 2.5 °C higher in 5% butanol solution (50.0 °C) than that in butanol-free solution (47.5 °C). At 45-60 °C, Gbbs-free energy change, ∆G, was higher in 5% butanol solution than that in butanol-free solution. The content of α-helix and ß-sheet increased in 5% butanol solution. The increasing of α-helix and ß-sheet content led to higher activity and better thermostability in butanol solution. The cold active butanol-tolerant endoglucanase was valuable for biobutanol production by a simultaneous saccharification and fermentation process.

[Identification of bear bile powder and its adulterants by using DNA barcoding technology].

To identify the precious bile powder and its adulterants by DNA barcoding, and establish its standard experimental process to ensure the safe and effective utilization. Total twelve sequences from samples of bear bile powder which come from Ursus thibetanus for DNA extraction, PCR(polymerase chain reaction) and sequence, then using CodonCode Aligner V 7.0.1 shear primer region to obtain COI sequence. The COI sequences of U. arctos and their adulterants were obtained from GenBank. MEGA7.0 software was applied for analyzing mutation, calculating intraspecific and interspecific K2P(Kimura 2-Parameter) genetic distance and constructing the Neighbor-joining tree(NJ). The results showed that the maximum K2P genetic distance of bear bile powder of U. thibetanus and U. arctos are far less than minimum K2P genetic distance within its adulterants species, and the results of NJ tree demonstrated that each species could be distinguished from the counterfeits obviously. DNA barcoding is a safe, convenient and reliable technique for species identification, and it is important to establish the standard sequence of COI sequences for animal medicines.

[Primary exploration of key influential factors recognization method of Tanreqing injection].

To recognize the key influential factors during the liquid preparation process of Tanreqing injection, the near infrared(NIR) spectra of the raw materials and the operating parameters of 24 batches of physical manufacturing were recorded as independent variables, and the total soluble solids contents and the light inspection acceptance rate of the final products were collected as dependent variables. The calibration models were developed using the partial least-square regression (PLSR) method, and the correlation coefficients between the independent variables and the dependent variables were calculated. For the quantitative models, the correlation coefficients for the calibration and inner cross validation of total soluble solids contents and the light inspection acceptance rate reached 0.911 9, 0.724 2 and 0.873 8, 0.795 9, respectively. Using the correlation coefficients diagrams, several key influence factors were preliminarily determined, and the physical significance were analyzed combined with production experience. This work demonstrated that NIR spectroscopy with PLSR algorithm could be used for the key influential factors recognization during the liquid preparation process of Tanreqing injection and can be popularized to solve similar problems..

Thermal Inactivation Kinetics and Secondary Structure Change of a Low Molecular Weight Halostable Exoglucanase from a Marine Aspergillus niger at High Salinities.

Two kinds of exoglucanase were purified from a marine Aspergillus niger. Catalytic ability of halophilic exoglucanase with a lower molecular weight and secondary structure change was analyzed at different salinities. Activity of the low molecular weight exoglucanase in 10% NaCl solution (w/v) was 1.69-fold higher of that in NaCl-free solution. Half-life time in 10% NaCl solution (w/v) was over 1.27-fold longer of that in NaCl-free solution. Free energy change of the low molecular weight exoglucanase denaturation, △G, in 10% NaCl solution (w/v) was 0.54 kJ/mol more than that in NaCl-free solution. Melt point in 10% NaCl solution (w/v), 52.01 °C, was 4.21 °C higher than that in NaCl-free solution, 47.80 °C. K m value, 0.179 mg/ml in 10% NaCl solution (w/v) was less 0.044 mg/ml than that, 0.224 mg/ml, in NaCl-free solution. High salinity made content of α-helix increased. Secondary structure change caused by high salinities improved exoglucanase thermostability and catalysis activity. The halophilic exoglucanase from a marine A. niger was valuable for hydrolyzing cellulose at high salinities.