Publications by authors named "Li Xiang"

4,507 Publications

  • Page 1 of 1

Revealing the heating value characteristics of sludge-based hydrochar in hydrothermal process: from perspective of hydrolysate.

Water Res 2021 Apr 21;198:117170. Epub 2021 Apr 21.

Shanghai Institute for Design & Research on Environmental Engineering Co., Ltd; Shanghai Environmental Sanitation Engineering Design Institute Co., Ltd.

Hydrothermal treatment (HT) is a promising method to convert sewage sludge to hydrochar biofuel. The heating value is directly correlated to the carbon content in hydrochar; however, the release of organic matter from sludge to hydrolysate and the transfer of the Maillard reaction products generated in the hydrolysate to the solid phase alter the carbon content in hydrochar. In this study, the relationship between hydrolysate and heating value of sludge-based hydrochar was presented, aiming to explain how the calorific value of hydrochar was affected by HT conditions. We adopted a direct combustion test to verify its clean combustion features. Hydrochar derived at 260 °C and residence time of 4 h (HC 260-4) exhibited the highest calorific value (HHV = 26.23 MJ/kg) with an energy density of 1.43, and its fuel characteristics were similar to those of lignite. The increase in the HT temperature and residence time up to 260 °C and 4 h, respectively, was beneficial for enhancing HHV. Conversely, further increase of the HT temperature to 300 °C and HT time to 6 h yielded a decrease in HHV. Investigation of the underlying mechanism revealed that the protein and polysaccharide releasing from sludge to hydrolysate occurred the Maillard reaction (MR). The generated humic-like Maillard reaction product (MRP) was transferred to hydrochar, inducing an increase in the carbon content and calorific value and a decrease in the organic content of hydrolysate. As the carbohydrate content in the hydrolysate decreased, the MR was terminated, so no more MRP was transferred to hydrochar. At the same time, the protein was still continuously released at higher temperatures and longer residence times, yielding a decline in the HHV. Moreover, clean energy utilization was verified from the reduced nitrogen content in hydrochar and lower CO and NO emission of HC 260-4 in the combustion test. After the HT, increased hydrophobicity and a lower fraction of bound water improved the dewaterability, which is of great significance for applying hydrochar as biofuel. The findings of this study provided a new perspective to explain the heating value generation of hydrochar and more direct evidence to assess its clean combustion properties, with promising perspectives for practical applications.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.watres.2021.117170DOI Listing
April 2021

PAN++: Towards Efficient and Accurate End-to-End Spotting of Arbitrarily-Shaped Text.

IEEE Trans Pattern Anal Mach Intell 2021 May 4;PP. Epub 2021 May 4.

Scene text detection and recognition have been well explored in the past few years. Despite the progress, efficient and accurate end-to-end spotting of arbitrarily-shaped text remains challenging. In this work, we propose an end-to-end text spotting framework, termed PAN++, which can efficiently detect and recognize text of arbitrary shapes in natural scenes. PAN++ is based on the kernel representation that reformulates a text line as a text kernel (central region) surrounded by peripheral pixels. By systematically comparing with existing scene text representations, we show that our kernel representation can not only describe arbitrarily-shaped text but also well distinguish adjacent text. Moreover, as a pixel-based representation, the kernel representation can be predicted by a single fully convolutional network, which is very friendly to real-time applications. Taking the advantages of the kernel representation, we design a series of components as follows: 1) a computationally efficient feature enhancement network composed of stacked Feature Pyramid Enhancement Modules (FPEMs); 2) a lightweight detection head cooperating with Pixel Aggregation (PA); and 3) an efficient attention-based recognition head with Masked RoI. Benefiting from the above designs, our method achieves high inference speed while maintaining competitive accuracy. Extensive experiments show the superiority of our method.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1109/TPAMI.2021.3077555DOI Listing
May 2021

Lysophosphatidic acid improves oocyte quality during IVM by activating the ERK1/2 pathway in cumulus cells and oocytes.

Mol Hum Reprod 2021 May 1. Epub 2021 May 1.

Assisted Reproduction Unit, Department of Obstetrics and Gynecology, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, China.

Oocyte IVM technology is an option for fertility preservation in some groups of patients, such as those with polycystic ovary syndrome, patients with ovarian hyperstimulation syndrome, and for patients with cancer. However, the developmental potential of oocytes from IVM still needs to improve. Several previous studies have reported that lysophosphatidic acid (LPA) promotes glucose metabolism, cumulus cell (CC) expansion, and oocyte nuclear maturation. However, the effect of LPA on oocyte cytoplasmic maturation, particularly mitochondrial function, has rarely been studied and the underlying mechanism is largely unknown, which impedes (pre)clinical applications of LPA. In this study, cumulus-oocyte complexes (COCs) and cumulus-denuded germinal vesicle oocytes (DOs) were treated with various concentrations of LPA during IVM, in the presence or absence of the oxidative stressor cyclophosphamide (CTX). In both normal and CTX-damaged COCs, the 25 μM LPA group exhibited improved CC expansion capacity, a higher nuclear maturation rate, and superior mitochondrial function, compared to no LPA treatment. When the concentration of LPA was over 40 μM, detrimental effects of LPA on oocyte maturation occurred. Compared with COCs, the addition of LPA slightly improved oocyte nuclear and cytoplasmic maturation of DOs, but this was not statistically significant. We observed that LPA promotes the activation of ERK1/2, although this was not statistically significant in DOs. Furthermore, LPA could not reverse the negative effect of CC expansion and mitochondrial function after inactivation of ERK1/2 by U0126. RNA-Sequencing and RT-PCR results showed that LPA upregulated several ERK1/2 downstream genes related to CC expansion, such as Areg, Cited4, and Ptgs2. This study demonstrates that LPA improves oocyte quality during IVM through the activation of ERK1/2 pathway CCs and oocytes, which provides evidence for the potential addition of LPA to IVM medium.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1093/molehr/gaab032DOI Listing
May 2021

Circ_0023404 sponges miR-136 to induce HK-2 cells injury triggered by hypoxia/reoxygenation via up-regulating IL-6R.

J Cell Mol Med 2021 May 4. Epub 2021 May 4.

Department of Nephrology, Affiliated Huai'an Hospital of Xuzhou Medical University, Huai'an, China.

The significance of circular RNAs (circRNAs) is reported in various kidney diseases including acute kidney injury (AKI). Specific circRNAs have the capacity to function as novel indicators of AKI. Circ_0023404 exhibits an important role in several diseases. Nevertheless, the detailed biological role of circ_0023404 in AKI remains poorly known. The present study aimed to investigate the effect of circ_0023404 on renal ischaemia/reperfusion (I/R) injury in vitro. Here, we evaluated the function of circ_0023404 in HK-2 cells in response to hypoxia/reoxygenation (H/R). We established a cell AKI model induced by H/R in HK-2 cells. We found circ_0023404 was significantly increased in AKI. Then, we found loss of circ_0023404 increased cell growth, repressed apoptosis, reduced inflammatory factors secretion and oxidative stress generation in vitro. Besides, circ_0023404 sponged miR-136. miR-136 overturned the effects of circ_0023404 on HK-2 cell injury. We assumed IL-6 receptor (IL-6R) as a target of miR-136 and IL-6R was activated by circ_0023404 via sponging miR-136. In conclusion, we revealed circ_0023404 contributed to HK-2 cells injury stimulated by H/R via sponging miR-136 and activating IL-6R.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/jcmm.15986DOI Listing
May 2021

Neuroprotective effect of helium after neonatal hypoxic ischemia: a narrative review.

Med Gas Res 2021 Jul-Sep;11(3):121-123

Department of Neurosurgery & Brain and Nerve Research Laboratory, the First Affiliated Hospital of Soochow University, Suzhou, Jiangsu Province, China.

Neonatal hypoxic ischemia is one of the leading causes of permanent morbidity and mortality in newborns, which is caused by difficulty in supplying blood and oxygen to brain tissue and is often associated with epilepsy, cerebral palsy, death, short-term or long-term neurological and cognitive impairment. In recent years, the clinical therapeutic effects of noble gases have been gradually discovered and recognized. Numerous studies have shown that noble gases have unique neuroprotective effects to restore damaged nerve and relieve symptoms in patients. Although research on the neuroprotective mechanisms of xenon and argon has yielded a lot of results, studies on helium have stalled. Helium is a colorless, odorless, monoatomic inert gas. The helium has no hemodynamic or neurocognitive side effects and can be used as an ideal pre-adaptor for future clinical applications. In recent years, studies have shown that heliox (a mixture of helium and oxygen) pretreatment can protect the heart, brain, liver and intestine from damage in several animal models, where a variety of signaling pathways have been proved to be involved. There are numerous studies on it even though the mechanism of helium for protecting newborns has not been fully elucidated. It is urgent to find an effective treatment due to the high death rate and disability rate of neonatal hypoxic ischemia. It is believed that helium will be approved safely and effectively for clinical use in the near future.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.4103/2045-9912.314332DOI Listing
May 2021

Risk factors for central lymph node metastasis in the cervical region in papillary thyroid carcinoma: a retrospective study.

World J Surg Oncol 2021 Apr 30;19(1):138. Epub 2021 Apr 30.

Department of Thyroid Surgery, The First Affiliated Hospital of Kunming Medical University, No. 295 Xichang Road, Kunming, 650032, Yunnan, China.

Background: To investigate the influence of different risk factors on central lymph node metastasis (CLNM) in the cervical region in patients with papillary thyroid carcinoma (PTC).

Methods: This retrospective study included 2586 PTC patients. Potential risk factors were identified by univariate analysis, and the relationships between these factors and CLNM were ascertained by multivariable analysis. A scoring system was constructed, and the optimal cut-off value was determined.

Results: On univariate analysis, sex, age, tumor diameter, multifocality, capsule invasion, vascular invasion, total number of lymph nodes in the central region, and serum thyroid peroxidase antibody (TPOAb) concentration were identified as potential risk factors for CLNM in the cervical region, whereas nerve invasion, thyroid-stimulating hormone concentration, and thyroglobulin antibody (TgAb) concentration were not. Multivariable analysis indicated that male sex, young age, large tumor diameter, multifocality, vascular invasion, a large number of central lymph nodes, and a low TPOAb concentration were significant risk factors. From these factors, a preoperative CLNM risk assessment scale was constructed for predicting CLNM in the cervical region for PTC patients.

Conclusion: Male sex, young age, large tumor diameter, multifocality, vascular invasion, a large number of central lymph nodes, and a low TPOAb concentration were positively correlated with CLNM in the cervical region in PTC patients. The preoperative CLNM risk assessment scale based on these risk factors is expected to offer accurate preoperative assessment of central lymph node status in PTC patients.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/s12957-021-02247-wDOI Listing
April 2021

Effects of music stimulus on behavior response, cortisol level, and horizontal immunity of growing pigs.

J Anim Sci 2021 May;99(5)

Key Laboratory of Swine Facilities Engineering, Ministry of Agriculture and Rural Affairs, College of Animal Science and Technology, Northeast Agricultural University, Harbin, Heilongjiang 150030, P.R. China.

An enriched environment is widely used to improve domestic animals' welfare and promote their natural behaviors. Music can reduce abnormal behavior in humans, nonhuman primates, and rodents. However, little is known about the effects of music on pigs. This study aims to explore the effects of repeated music stimulation on the behavior, physiology, and immunity of growing pigs. A total of 72 hybrid piglets (Large White × Duroc × Minpig) were randomly divided into three groups, including music (Mozart K.448, 60 to 70 dB), noise (recorded mechanical noise, 80 to 85 dB), and control (natural background sound, <40 dB), and 6 h sound stimulation was given per day (1000 to 1600 hours) from 40 to 100 d of age. The behavioral activities of the pigs were observed during the music stimulation, and their serum cortisol, salivary cortisol, and serum immune indices were also measured. Compared with the control group, the music group and noise group increased activity but decreased lying of pigs (P < 0.05). A significant increase in tail-wagging, playing, and exploring behaviors of pigs was found in the music group (P < 0.05), and the noise significantly increased the aggressive behavior of the pigs (P < 0.05). Tail-wagging, playing, exploring, manipulating, and aggressive behaviors decreased over time. Short-term (8 d) music stimulus had a lower cortisol level than that of the noise and control groups (P < 0.05), whereas long-term (60 d) music stimulus increased immunoglobulin G (IgG), interleukin-2 (IL-2), and interferon-gamma (IFN-γ) levels (P < 0.05) and decreased interleukin-4 (IL-4) level (P < 0.05). Long-term noise stimulus significantly reduced the level of IgG (P < 0.05) but did not affect the level of IL-2, IL-4, and IFN-γ levels (P > 0.05). In conclusion, short-term music stimulus (8 d) reduced the stress response, whereas long-term music stimulus (60 d) enhanced the immune responses. In addition, the noise increased the aggressive behavior, and long-term noise reduced the immunity of the growing pigs.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1093/jas/skab043DOI Listing
May 2021

An Interpretable Machine Learning Survival Model for Predicting Long-term Kidney Outcomes in IgA Nephropathy.

AMIA Annu Symp Proc 2020 25;2020:737-746. Epub 2021 Jan 25.

Ping An Healthcare Technology, Beijing.

IgA nephropathy (IgAN) is common worldwide and has heterogeneous phenotypes. Predicting long-term outcomes is important for clinical decision-making. As right-censored patients become common during the long-term follow-up, either excluding these patients from the cohort or labeling them as control will bias the risk estimation. Thus, we constructed a survival model using EXtreme Gradient Boosting for survival (XSBoost-Surv), to accurately predict the prognosis of IgAN patients by taking the time-to-event information into the modeling procedure. Shapley Additive exPlanations (SHAP) was employed to interpret the individual predicted result and the non-linear relationships between the predictors and outcome. Experiments on real-world data showed our model achieved superior discrimination performance over other conventional survival methods. By providing insights into the exact changes in risk induced by certain characteristics of the patients, this explainable and accurate survival model can help improve the clinical understanding of renal progression and benefit the therapies for the IgAN patients.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8075445PMC
January 2021

A Clinically Practical and Interpretable Deep Model for ICU Mortality Prediction with External Validation.

AMIA Annu Symp Proc 2020 25;2020:629-637. Epub 2021 Jan 25.

PingAn Health Technology, Beijing, China.

Deep learning models are increasingly studied in the field of critical care. However, due to the lack of external validation and interpretability, it is difficult to generalize deep learning models in critical care senarios. Few works have validated the performance of the deep learning models with external datasets. To address this, we propose a clinically practical and interpretable deep model for intensive care unit (ICU) mortality prediction with external validation. We use the newly published dataset Philips eICU to train a recurrent neural network model with two-level attention mechanism, and use the MIMIC III dataset as the external validation set to verify the model performance. This model achieves a high accuracy (AUC = 0.855 on the external validation set) and have good interpretability. Based on this model, we develop a system to support clinical decision-making in ICUs.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8075474PMC
January 2021

Design, synthesis, and biological evaluation of stapled ascaphin-8 peptides.

Bioorg Med Chem 2021 Apr 22;40:116158. Epub 2021 Apr 22.

Institute of Translational Medicine, Shanghai University, Shanghai 200444, China. Electronic address:

Ascaphin-8 is an α-helical anti-tumor and antimicrobial peptide containing 19 residues, which was isolated from norepinephrine-stimulated skin secretions of the North American tailed frog Ascaphus truei. To improve both its stability and biological activities, a series of hydrocarbon-stapled analogs of Ascaphin-8 were synthesized and investigated for their potential antiproliferative activities. The activity studies were evaluated using the CCK-8 method and colony formation assay on human cancer cell lines. Ascaphin-8-3, as the most active peptide, showed a stronger inhibition effect when compared with the parent peptide for the tested cell lines. In addition, the effect of Ascaphin-8-3 on inhibiting the metastatic capabilities of A549 cells was more powerful than that of the parent peptide. This peptide derivative showed potentiality for further optimization in antitumor drugs.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.bmc.2021.116158DOI Listing
April 2021

MIR99AHG is a noncoding tumor suppressor gene in lung adenocarcinoma.

Cell Death Dis 2021 Apr 30;12(5):424. Epub 2021 Apr 30.

Department of Thoracic Surgery, Jiangsu Key Laboratory of Molecular and Translational Cancer Research, the Affiliated Cancer Hospital of Nanjing Medical University & Jiangsu Cancer Hospital & Jiangsu Institute of Cancer Research, Nanjing, China.

Little is known about noncoding tumor suppressor genes. An effective way to identify these genes is by analyzing somatic copy number variation (CNV)-related noncoding genes. By integrated bioinformatics analyses of differentially expressed long noncoding RNAs (lncRNAs) and arm-level CNVs in lung adenocarcinoma (LUAD), we identified a potential antitumor gene, MIR99AHG, encoding lncRNA MIR99AHG as well as a miR-99a/let-7c/miR-125b2 cluster on chromosome 21q. All four of these transcripts were downregulated in LUAD tissues partly due to the copy number deletion of the MIR99AHG gene. Both MIR99AHG and miR-99a expression was positively correlated with the survival of LUAD patients. MIR99AHG suppressed proliferation and metastasis and promoted autophagy both in vitro and in vivo. Mechanistically, the interaction between MIR99AHG and ANXA2 could accelerate the ANXA2-induced ATG16L vesicle biogenesis, thus promoting phagophore assembly. Additionally, miR-99a targeted a well-known autophagy suppressor, mammalian target of rapamycin (mTOR), thereby synergistically promoting autophagy and postponing LUAD progression with MIR99AHG. In summary, MIR99AHG emerges as a noncoding tumor suppressor gene in LUAD, providing a new strategy for antitumor therapy.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41419-021-03715-7DOI Listing
April 2021

A dissecting aneurysm of the sinus of Valsalva involving the inter-ventricsular septum in a patient with syphilis and a quadricuspid aortic valve.

Echocardiography 2021 Apr 30. Epub 2021 Apr 30.

Cardiology Department, West China Hospital, Sichuan University, China.

Aneurysms of the sinus of Valsalva are rare, with dissecting aneurysms of the sinus of Valsalva that extend into the inter-ventricular septum being even more rare. This report describes a young patient with syphilis and a quadricuspid aortic valve who experienced a spontaneously dissecting aneurysm of the sinus of Valsalva and the basal inter-ventricular septum.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/echo.15055DOI Listing
April 2021

Clinical Characteristics of Patients With Dizziness/Vertigo Accompanied by Posterior Semicircular Canal Hypofunction.

Front Med (Lausanne) 2021 13;8:589969. Epub 2021 Apr 13.

Department of Neurology, Aerospace Center Hospital, Peking University Aerospace School of Clinical Medicine, Beijing, China.

To investigate the clinical characteristics of patients with dizziness/vertigo accompanied by loss of the posterior canal(s) (LPC). Clinical data of 23 patients with LPC were collected. We determined video-head-impulse test (vHIT) gains of all six semicircular canals and correlated vHIT findings with other vestibulo-cochlear tests, including caloric test, ocular and cervical vestibular-evoked myogenic potentials (oVEMP, cVEMP), pure tone audiometry (PTA), and analyzed the differences in clinical manifestations of patients with LPC with different etiologies. LPC was identified in 23 patients. At the time of disease onset, most patients presented with dizziness (47.8%) and vertigo (30.4%) only, and some patients (21.7%) complained of unsteadiness. Among these 23 patients with LPC, there were 14 (60.9%) patients of isolated LPC (ILPC), 21 (91.3%) patients of unilateral LPC (ULPC), and 2 (8.7%) patients of bilateral LPC (BLPC). (1) Among 14 patients with ILPC, 13 (92.9%) patients had unilateral ILPC, the rate of ipsilesional impairment on caloric test, or oVEMP/cVEMP test or PTA ipsilesionally was 53.8% (7/13) in patients with unilateral ILPC. The causes of unilateral ILPC were vertigo/dizziness of unclear origin (38.5%), labyrinthine infarction (15.4%), vestibular migraine (15.4%), and other diseases (30.8%); (2) among 21 patients with ULPC, 7 patients (33.3%) were accompanied with horizontal semicircular canal hypofunction ipsilesionally, the abnormal rate of caloric test, or oVEMP/cVEMP tests or PTA ipsilesionally was 57.1%. The causes of ULPC were vertigo/dizziness of unclear origin (33.3%), autoimmune inner ear disease (14.3%), labyrinthine infarction (14.3%), vestibular neuritis (9.5%), vestibular migraine (9.5%), and other diseases (19.0%); (3) among two patients with BLPC, one patient presented with unsteadiness, the causes of BLPC were vestibular paroxysmia and autoimmune inner ear disease. vHIT is a fast and effective method for assessing LPC, which can be used to detect isolated PC dysfunction. The causes of ILPC were peripheral origin or central origin. Patients with ILPC and ULPC mostly presented with dizziness/vertigo, and ULPC was often accompanied by ipsilateral vestibulo-cochlear impairment.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3389/fmed.2021.589969DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8076509PMC
April 2021

Machine Learning-Inspired Hybrid Precoding for mmWave MU-MIMO Systems with Domestic Switch Network.

Sensors (Basel) 2021 Apr 25;21(9). Epub 2021 Apr 25.

National Mobile Communications Research Laboratory, Southeast University, Nanjing 210096, China.

Hybrid precoding is an attractive technique in MU-MIMO systems with significantly reduced hardware costs. However, it still requires a complex analog network to connect the RF chains and antennas. In this paper, we develop a novel hybrid precoding structure for the downlink transmission with a compact RF structure. Specifically, the proposed structure relies on domestic connections instead of global connections to link RF chains and antennas. Fixed-degree phase shifters provide candidate signals, and simple on-off switches are used to route the signal to antennas, thus RF adders are no longer required. Baseband zero forcing and block diagonalization are used to cancel interference for single-antenna and multiple-antenna users, respectively. We formulate how to design the RF precoder by optimizing the probability distribution through cross-entropy minimization which originated in machine learning. To optimize the energy efficiency, we use the fractional programming technique and exploit the Dinkelbach method-based framework to optimize the number of active antennas. Simulation results show that proposed algorithms can yield significant advantages under different configurations.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3390/s21093019DOI Listing
April 2021

Development of a High Internal Phase Emulsion of Antarctic Krill Oil Diluted by Soybean Oil Using Casein as a Co-Emulsifier.

Foods 2021 Apr 22;10(5). Epub 2021 Apr 22.

School of Food Science and Technology, Dalian Polytechnic University, Dalian 116034, China.

Antarctic krill oil (AKO) with 5-30% () dilution by soybean oil was co-emulsified by phospholipids (PLs) naturally present in AKO and 2% () casein in the aqueous phase to prepare high internal phase emulsions (HIPEs). The results showed that raising the AKO level resulted in concave-up changes in the mean size of oil droplets which became more densely packed. Confocal laser scanning microscopy (CLSM) and cryo-scanning electron microscopy (cryo-SEM) micrographs revealed that PLs at higher concentrations expelled more casein particles from the oil droplet surface, which facilitated the formation of a crosslinked network structure of HIPEs, leading to reduced mobility of water molecules, extended physical stability, and somewhat solid-like behavior. The rheological analysis showed at lower levels of AKO promoted fluidity of emulsions, while at higher levels it increased elasticity. Lastly, increasing the AKO level slowed down the oxidation of HIPEs. These findings provide useful insights for developing HIPEs of highly viscous AKO and its application in foods.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3390/foods10050917DOI Listing
April 2021

HS Attenuates Sleep Deprivation-Induced Cognitive Impairment by Reducing Excessive Autophagy via Hippocampal Sirt-1 in WISTAR RATS.

Neurochem Res 2021 Apr 29. Epub 2021 Apr 29.

Hengyang Key Laboratory of Neurodegeneration and Cognitive Impairment, Institute of Neuroscience, Hengyang Medical College, University of South China, 28 W Changsheng Road, Hengyang, 421001, Hunan, P. R. China.

Sleep deprivation (SD) is widespread in society causing serious damage to cognitive function. Hydrogen sulfide (HS), the third gas signal molecule, plays important regulatory role in learning and memory functions. Inhibition of excessive autophagy and upregulation of silent information regulator 1 (Sirt-1) have been reported to prevent cognitive dysfunction. Therefore, this present work was to address whether HS attenuates the cognitive impairment induced by SD in Wistar rats and whether the underlying mechanisms involve in inhibition of excessive autophagy and upregulation of Sirt-1. After treatment with SD for 72 h, the cognitive function of Wistar rats was evaluated by Y-maze, new object recognition, object location, and Morris water maze tests. The results shown that SD-caused cognitive impairment was reversed by treatment with NaHS (a donor of HS). NaHS also prevented SD-induced hippocampal excessive autophagy, as evidenced by the decrease in autophagosomes, the down-regulation of Beclin1, and the up-regulation of p62 in the hippocampus of SD-exposed Wistar rats. Furthermore, Sirtinol, an inhibitor of Sirt-1, reversed the inhibitory roles of NaHS in SD-induced cognitive impairment and excessive hippocampal autophagy in Wistar rats. Taken together, our results suggested that HS improves the cognitive function of SD-exposed rats by inhibiting excessive hippocampal autophagy in a hippocampal Sirt-1-dependent way.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s11064-021-03314-0DOI Listing
April 2021

Curcumin Alleviates Chronic Pain and Improves Cognitive Impairment via Enhancing Hippocampal Neurogenesis in Sciatic Nerve Constriction Rats.

J Pain Res 2021 20;14:1061-1070. Epub 2021 Apr 20.

Department of Anesthesiology, The Third Affiliated Hospital, Sun Yat-Sen University, Guangzhou, People's Republic of China.

Purpose: Cognitive impairment is a complication that most frequently happens in patients with chronic neuropathic pain and has limited effective therapy. The aim of this study was to explore the effects of curcumin on the cognitive deficit in rats with peripheral nerve injury induced-neuropathic pain.

Methods: The neuropathic pain rat model was constructed using chronic constriction injury (CCI). The curcumin (60 mg/kg) or vehicle was intraperitoneally administered once a day, beginning at 14th day after surgery and continued for 14 consecutive days. The nociceptive threshold tests were measured by paw mechanical withdraw threshold (PMWT) and paw thermal withdrawal latency (PTWL), while the spatial memory abilities were evaluated by the Morris water maze test. The mean counts of bromodeoxyuridine (Brdu)/neuronal nuclei (NeuN) as well as Brdu/doublecortin (DCX) co-labeled cells were used to evaluate neurogenesis in the dentate gyrus of hippocampus. The ultrastructure of the synapse in hippocampal region was visualized using transmission electron microscopy (TEM).

Results: Increased PMWT and PTWL, as well as relieved memory deficits, were found in CCI rats under curcumin administration. Moreover, curcumin treatment increased the number of newly born immature (BrdU/NeuN) and newly generated mature neurons (BrdU/DCX). The TEM examination revealed increased PSD thickness and shorter active zone length as well as narrowed synaptic cleft width in the hippocampal region of CCI rats after curcumin injection.

Conclusion: Curcumin can alleviate CCI induced nociceptive behaviors and memory deficit. This effect might be associated with hippocampal neurogenesis and synaptic plasticity improvements, which indicated curcumin as a potential strategy for the cognitive impairment restoration under prolonged neuropathic pain condition.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.2147/JPR.S299604DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8069680PMC
April 2021

HMGCR inhibition stabilizes the glycolytic enzyme PKM2 to support the growth of renal cell carcinoma.

PLoS Biol 2021 Apr 27;19(4):e3001197. Epub 2021 Apr 27.

Bio-manufacturing Engineering Laboratory, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen, Guangdong, China.

Renal cell carcinoma (RCC) is responsible for most cases of the kidney cancer. Previous research showed that low serum levels of cholesterol level positively correlate with poorer RCC-specific survival outcomes. However, the underlying mechanisms and functional significance of the role of cholesterol in the development of RCC remain obscure. 3-Hydroxy-3-methylglutaryl coenzyme A reductase (HMGCR) plays a pivotal role in RCC development as it is the key rate-limiting enzyme of the cholesterol biosynthetic pathway. In this study, we demonstrated that the inhibition of HMGCR could accelerate the development of RCC tumors by lactate accumulation and angiogenesis in animal models. We identified that the inhibition of HMGCR led to an increase in glycolysis via the regulated HSP90 expression levels, thus maintaining the levels of a glycolysis rate-limiting enzyme, pyruvate kinase M2 (PKM2). Based on these findings, we reversed the HMGCR inhibition-induced tumor growth acceleration in RCC xenograft mice by suppressing glycolysis. Furthermore, the coadministration of Shikonin, a potent PKM2 inhibitor, reverted the tumor development induced by the HMGCR signaling pathway.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1371/journal.pbio.3001197DOI Listing
April 2021

Human Endogenous Retroviruses as Biomedicine Markers.

Virol Sin 2021 Apr 27. Epub 2021 Apr 27.

CAS Key Laboratory of Molecular Virology and Immunology, Institut Pasteur of Shanghai, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Shanghai, 200031, China.

Human endogenous retroviruses (HERVs) were formed via ancient integration of exogenous retroviruses into the human genome and are considered to be viral "fossils". The human genome is embedded with a considerable amount of HERVs, witnessing the long-term evolutionary history of the viruses and the host. Most HERVs have lost coding capability during selection but still function in terms of HERV-mediated regulation of host gene expression. In this review, we summarize the roles of HERV activation in response to viral infections and diseases, and emphasize the potential use of HERVs as biomedicine markers in the early diagnosis of diseases such as cancer, which provides a new perspective for the clinical application of HERVs.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s12250-021-00387-7DOI Listing
April 2021

Asymmetric Palladium-Catalyzed Oxycarbonylation of Terminal Alkenes: Efficient Access to β-Hydroxy Alkylcarboxylic Acids.

Angew Chem Int Ed Engl 2021 Apr 26. Epub 2021 Apr 26.

Shanghai Institute of Organic Chemistry, State Key Laboratory of Organometallic Chemistry, 345 Lingling Road, Shanghai, China, 200032, Shanghai, CHINA.

A novel Pd(II)-catalyzed enantioselective oxycarbonyl-ation of alkenes has been established herein. The ligand with an ethyl group at the C-6 position of Pyox plays a significant role in the intermolecular oxypalladation process, leading to high reactivity and excellent enantioselective control. Compared to the conventional methods, the reaction itself features alkenes as easily prepared starting materials, mild and operationally simple reaction conditions, and insensitivities to air and water. Moreover, this method allows for broad alkene substrate scope, excellent regio- and enantio-selectivities, scalabilities and a wide array of applications, and provides a useful route for the convenient and straightforward synthesis of chiral β -hydroxy alkylcarboxylic acids/esters.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/anie.202104252DOI Listing
April 2021

Free-recall benefit, inhomogeneity and between-item interference in working memory.

Cognition 2021 Apr 23;214:104739. Epub 2021 Apr 23.

Center for Brain and Mental Well-being, Department of Psychology, Sun Yat-sen University, Guangzhou, China; Peng Cheng Laboratory, Shenzhen, China; Shanghai Key Laboratory of Brain Functional Genomics, Shanghai Changning-ECNU Mental Health Center, School of Psychology and Cognitive Science, East China Normal University, Shanghai, China; NYU-ECNU Institute of Brain and Cognitive Science, NYU Shanghai and Collaborative Innovation Center for Brain Science, Shanghai, China. Electronic address:

We investigated visual working memory (VWM) with a whole-report task, where participants were asked to sequentially recall all the items in an order either chosen by themselves (free recall) or randomly chosen by the computer (forced recall). Comparisons between free and forced recalls helped us understand important but largely neglected aspects of VWM, such as inhomogeneity (different levels of precision) and between-item interference. One unique part of our task was the introduction of a separate item-selection stage before each recall, during which participants located the next item to recall. Their mouse trajectory was recorded and served as a dynamic measure of between-item interference over time. We found a free-recall benefit: the overall precision of all items is higher in free recall than in forced recall. Meanwhile, during item-selection, free recall is associated with faster localization of the target and less interference from the other items in memory. We also found evidence for inhomogeneity and discuss the connection of inhomogeneity and between-item interference to the free-recall benefit.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.cognition.2021.104739DOI Listing
April 2021

Micro-Doppler Effects Removed Sparse Aperture ISAR Imaging via Low-Rank and Double Sparsity Constrained ADMM and Linearized ADMM.

IEEE Trans Image Process 2021 3;30:4678-4690. Epub 2021 May 3.

Inverse synthetic aperture radar (ISAR) imaging for the target with micro-motion parts is influenced by the micro-Doppler (m-D) effects. In this case, the radar echo is generally decomposed into the components from the main body and micro-motion parts of target, respectively, to remove the m-D effects and derive a focused ISAR image of the main body. For the sparse aperture data, however, the radar echo is intentionally or occasionally under-sampled, which defocuses the ISAR image by introducing considerable interference, and deteriorates the performance of signal decomposition for the removal of m-D effects. To address this issue, this paper proposes a novel m-D effects removed sparse aperture ISAR (SA-ISAR) imaging algorithm. Note that during a short interval of ISAR imaging, the range profiles of the main body of target from different pulses are similar, resulting in a low-rank matrix of range profile sequence of main body. For the range profiles of the micro-motion parts, they either spread in different range cells or glint in a single range cell, which results in a sparse matrix of range profile sequence. From this perspective, the low-rank and sparse properties are utilized to decompose the range profiles of the main body and micro-motion parts, respectively. Moreover, the sparsity of ISAR image is also utilized as a constraint to eliminate the interference caused by sparse aperture. Hence, SA-ISAR imaging with the removal of m-D effects is modeled as a triply constrained underdetermined optimization problem. The alternating direction method of multipliers (ADMM) and linearized ADMM (L-ADMM) are further utilized to solve the problem with high efficiency. Experimental results based on both simulated and measured data validate the effectiveness of the proposed algorithm.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1109/TIP.2021.3074271DOI Listing
May 2021

Design of Nitroso-Modified Naphthylene-Based Fluorophores as Photoactivatable Bioorthogonal Turn-On Probes.

Org Lett 2021 Apr 26. Epub 2021 Apr 26.

State Key Laboratory of Bioactive Substances and Function of Natural Medicine, Beijing Key Laboratory of Active Substances Discovery and Drugability Evaluation, Institute of Materia Medica, Peking Union Medical College and Chinese Academy of Medical Sciences, 1 Xian Nong Tan Street, Beijing 100050, China.

We reported a series of nitroso-modified naphthylene-based fluorophores as novel bioorthogonal fluorescence turn-on probes. The cycloadducts from nitroso-diene Diels-Alder reaction could be either photochemically or spontaneously transformed into highly fluorescent rearrangement products with remarkable photophysical properties including significant fluorescence enhancement, large Stokes shift, high fluorescence quantum yield, superior photostability, and distinct solvatochromic effect. This strategy is suitable for selective labeling of diene-modified proteins and visualizing specific organelles in live mammalian cells under no-wash conditions.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acs.orglett.1c01226DOI Listing
April 2021

Effect of self-assembly on fluorescence in magnetic multiphase flows and its application on the novel detection for COVID-19.

Phys Fluids (1994) 2021 Apr 6;33(4):042004. Epub 2021 Apr 6.

Department of Mechanical Engineering, Tsinghua University, Beijing 100084, China.

In the present study, the magnetic field induced self-assembly processes of magnetic microparticles in an aqueous liquid (the pure magnetic fluid) and nonmagnetic microparticles in ferrofluid (the inverse magnetic fluid) are experimentally investigated. The microparticles are formed into chain-like microstructures in both the pure magnetic fluid and the inverse magnetic fluid by applying the external magnetic field. The fluorescence parameters of these self-assembled chain-like microstructures are measured and compared to those without the effect of magnetic field. It is found that the fluorescence in the pure magnetic fluid is weakened, because the scattering and illuminating areas are reduced in the microstructures. On the contrary, the fluorescence in the inverse magnetic fluid is enhanced, because more fluorescent nonmagnetic microparticles are enriched and become detectable under the effect of the magnetic dipole force and the magnetic levitational force, and their unnecessary scattering can be absorbed by the surrounding ferrofluid. The average enhancement of the fluorescence area ratio in the inverse magnetic fluid with 3 m nonmagnetic microparticles reaches 112.92%. The present work shows that the inverse magnetic fluid has advantages such as low cost, no scattering effect, stable fluorescence intensity, and relatively low magnetic resistance. In the end, a prototype design for the novel detection of coronavirus disease 2019 based on the magnetic field induced self-assembly in the inverse magnetic fluid is proposed, which could support the epidemic prevention and control.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1063/5.0048123DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8060970PMC
April 2021

A tri-functional amino acid enables mapping of binding sites for posttranslational-modification-mediated protein-protein interactions.

Mol Cell 2021 Apr 15. Epub 2021 Apr 15.

Department of Chemistry, The University of Hong Kong, Pokfulam, Hong Kong, China. Electronic address:

Posttranslational modification (PTM), through the recruitment of effector proteins (i.e., "readers") that signal downstream events, plays key roles in regulating a variety of cellular processes. To understand how a PTM is recognized, it is necessary to find its readers and, importantly, the location of the binding pockets responsible for PTM recognition. Although various methods have been developed to identify PTM readers, it remains a challenge to directly map the PTM-binding regions, especially for intrinsically disordered domains. Here, we demonstrate a photo-crosslinkable, clickable, and cleavable tri-functional amino acid, ADdis-Cys, that when coupled with mass spectrometry (ADdis-Cys-MS) can not only identify PTM readers from complex proteomes but also simultaneously map their PTM-recognition modules. Using ADdis-Cys-MS, we successfully identify the binding sites of several reader-PTM interactions, among which we discover human C1QBP as a histone chaperone. This robust method should find wide applications in examining other histone or non-histone PTM-mediated protein-protein interactions.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.molcel.2021.04.001DOI Listing
April 2021

Highly Ordered 3D Tissue Engineering Scaffolds as a Versatile Culture Platform for Nerve Cells Growth.

Macromol Biosci 2021 Apr 24:e2100047. Epub 2021 Apr 24.

Dongyuan Synergy Innovation Institute for Modern Industries of GDUT, Guangdong University of Technology, Guangzhou, 510006, China.

Tissue engineering scaffolds provide an encouraging alternative for nerve injuries due to their biological support for nerve cell growth, which can be used for neuronal repair. Nerve cells have been reported to be mostly cultured on 2D scaffolds that cannot mimic the native extracellular matrix. Herein, highly ordered 3D scaffolds are fabricated for nerve cell culture by melt electrospinning writing, the microstructures and geometries of the scaffolds could be well modulated. An effective strategy for scaffold surface modification to promote nerve cell growth is proposed. The effects of scaffolds with different surface modifications, viz., plasma treatment, single poly-D-lysine (PDL) coating after plasma treatment, single laminin (LM) coating after plasma treatment, double PDL and LM coatings after plasma treatment, on PC12 cell growth are evaluated. Experiments show the scaffold modified with double PDL and LM coatings after plasma treatment facilitated the growth of PC12 cells most effectively, indicating the synergistic effect of PDL and LM on the growth of nerve cells. This is the first systematic and quantitative study of the effects of different scaffold surface modifications on nerve cell growth. The above results provide a versatile culture platform for growing nerve cells, and for recovery from peripheral nerve injury.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/mabi.202100047DOI Listing
April 2021

Biomimetic Nanotheranostics Camouflaged with Cancer Cell Membranes Integrating Persistent Oxygen Supply and Homotypic Targeting for Hypoxic Tumor Elimination.

ACS Appl Mater Interfaces 2021 Apr 23. Epub 2021 Apr 23.

Institute of Orthopedics, Department of Orthopedics, The Affiliated Hospital of Xuzhou Medical University, Xuzhou, Jiangsu 221002, P. R. China.

Treatment resistance of the tumors to photodynamic therapy (PDT) owing to O deficiency largely compromised the therapeutic efficacy, which could be addressed modulating oxygen levels by using O self-enriched nanosystems. Here, we report on augmenting the O-evolving strategy based on a biomimetic, catalytic nanovehicle (named as N/P@MCC), constructed by the catalase-immobilized hollow mesoporous nanospheres by enveloping a cancer cell membrane (CCM), which acts as an efficient nanocontainer to accommodate nitrogen-doped graphene quantum dots (N-GQDs) and protoporphyrin IX (PpIX). Inheriting the virtues of biomimetic CCM cloaking, the CCM-derived shell conferred N/P@MCC nanovehicles with highly specific self-recognition and homotypic targeting toward cancerous cells, ensuring tumor-specific accumulation and superior circulation durations. N-GQDs, for the first time, have been evidenced as a new dual-functional nanoagents with PTT and PDT capacities, enabling the generation of O for PDT and inducing local low-temperature hyperthermia for thermally ablating cancer cells and infrared thermal imaging (IRT). Leveraging the intrinsic catalytic features of catalase, such N/P@MCC nanovehicles effectively scavenged the excessive HO to sustainably evolve oxygen for a synchronous O self-supply and hypoxia alleviation, with an additional benefit because the resulting O bubbles could function as an echo amplifier, leading to the sufficient echogenic reflectivity for ultrasound imaging. Concurrently, the elevated O reacted with N-GQDs and PpIX to elicit a maximally increased O output for augmented PDT. Significantly, the ultrasound imaging coupled with fluorescence imaging, IRT, performs a tumor-modulated trimodal bioimaging effect. Overall, this offers a paradigm to rationally explore O self-supply strategies focused on versatile nanotheranostics for hypoxic tumor elimination.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acsami.1c03010DOI Listing
April 2021

Tumor-associated macrophages secret exosomal miR-155 and miR-196a-5p to promote metastasis of non-small-cell lung cancer.

Transl Lung Cancer Res 2021 Mar;10(3):1338-1354

Department of Thoracic Surgery, Jiangsu Province People's Hospital and the First Affiliated Hospital of Nanjing Medical University, Nanjing, China.

Background: Understanding the molecular basis underlying metastasis of non-small cell lung cancer (NSCLC) may provide a new therapeutic modality for the treatment of NSCLC. However, the mechanisms by which tumor-associated macrophages (TAMs) affect NSCLC metastasis remain undefined. In this study, we aimed to discover a novel regulatory pathway involved in NSCLC metastasis.

Methods: Cell Counting Kit-8 (CCK-8), Transwell, western blot assays were used to assess cell viability, migration, invasion and epithelial-mesenchymal transition (EMT). Exosomes from macrophages medium were characterized, and in vitro cell coculture was further conducted to investigate M2 derived exosomes mediated crosstalk between TAMs and tumor cells. Besides, miRNA microarray was used to analyze miRNA expression profiles of M0 and M2 derived exosomes. Luciferase reporter assay was used to verify the potential binding between miRNA and mRNA. Moreover, 6-week-old male BALB/c nude mice were performed to establish transplantation tumor model using tail vein injection. Hematoxylin & eosin staining was used to detect the metastasis of tumor tissues.

Results: We found that M2 TAMs were the main TAMs in metastatic tissues of NSCLC patients and exosomes derived from M2 TAMs were able to promote cell viability, cell migration, cell invasion and EMT in NSCLC. We demonstrated that miR-155 and miR-196a-5p were abundant in M2 TAMs and exosomes secreted by M2 TAMs. Functional experiments demonstrated that the deletion of miR-155 and miR-196a-5p in M2 TAMs significantly prevented NSCLC metastasis and . To clarify the mechanism governing miR-155 and miR-196a-5p from M2 TAMs, we carried out bioinformatics analysis to predict potential target genes. Mechanistically, miR-155 and miR-196a-5p directly bound to the 3'-UTR of Ras association domain family member 4 (RASSF4), and negatively regulating RASSF4 expression. At last, rescue assays demonstrated that miR-155 and miR-196a-5p exerted its performance by RASSF4.

Conclusions: Overall, we revealed a new regulatory pathway that was M2 TAMs secreted exosomal miR-155 and miR-196a-5p to promote NSCLC metastasis. This dynamic and reciprocal cross-talk between NSCLC and macrophages innovatively provided a potential opportunity for diagnosis and treatment of NSCLC.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.21037/tlcr-20-1255DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8044469PMC
March 2021

Deep sequencing reveals the genomic characteristics of lung adenocarcinoma presenting as ground-glass nodules (GGNs).

Transl Lung Cancer Res 2021 Mar;10(3):1239-1255

Key Laboratory of Genomics and Precision Medicine, Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing, China.

Background: The concept of multi-step progression from atypical adenomatous hyperplasia (AAH) to invasive adenocarcinoma (ADC) has been proposed, and ground-glass nodules (GGNs) may play a critical role during the early lung tumorigenesis. We present the first comprehensive description of the genomic architecture of GGNs to unravel the genetic basis of GGN.

Methods: We investigated 30 GGN-like lungs ADC by performing >1,000× whole-exome sequencing (WES) and characterized the genomic variations and evaluate the relationship between the clinicopathologic and molecular characteristics in this disease.

Results: Despite the low somatic mutation burden, GGNs exhibited high intratumor heterogeneity (ITH) characterized by the proportion of subclonal mutations. Different mutagenesis shaped the genomes of GGN during cancer evolution and were mostly featured by molecular clock-like signatures that occur in clonal mutations and defective DNA mismatch signatures that occur in subclonal mutations. Moreover, 10.7-67.1% clonal mutations occurred after whole-genome doubling (WGD), indicating that WGD could be a frequent truncal event in GGNs. Samples with WGD showed higher genomic instability but lower ITH. These GGNs were characterized by recurrent focal copy-number changes that are highly associated with tumorigenesis, with only two genes ( and ) that were recurrently mutated. Additionally, GGNs with different pathological subtypes or computed tomography (CT) features exhibited distinct genetic characteristics. Lepidic predominant or pure GGNs in CT images carried a lower mutation burden and had a relatively stable genome than nonlepidic or mixed GGNs. GGNs with mutations tended to accompany a pathologically lepidic pattern, indicating may drive the distinct subtype of lung cancer with better prognosis.

Conclusions: These findings facilitated interpreting the genomic characteristics of GGNs, provided insight into the early stages of lung cancer evolution, and possessed potential clinical significance.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.21037/tlcr-20-1086DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8044491PMC
March 2021

Nanomechanics of Lignin-Cellulase Interactions in Aqueous Solutions.

Biomacromolecules 2021 Apr 21. Epub 2021 Apr 21.

Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta T6G 2V4, Canada.

Efficient enzymatic hydrolysis of cellulose in lignocellulose to glucose is one of the most critical steps for the production of biofuels. The nonproductive adsorption of lignin to expensive cellulase highly impedes the development of biorefinery. Understanding the lignin-cellulase interaction mechanism serves as a vital basis for reducing such nonproductive adsorption in their practical applications. Yet, limited report is available on the direct characterization of the lignin-cellulase interactions. Herein, for the first time, the nanomechanics of the biomacromolecules including lignin, cellulase, and cellulose were systematically investigated by using a surface force apparatus (SFA) at the nanoscale in aqueous solutions. Interestingly, a cation-π interaction was discovered and demonstrated between lignin and cellulase molecules through SFA measurements with the addition of different cations (Na, K, etc.). The complementary adsorption tests and theoretical calculations further confirmed the validity of the force measurement results. This finding further inspired the investigation of the interaction between lignin and other noncatalytic-hydrolysis protein (i.e., soy protein). Soy protein was demonstrated as an effective, biocompatible, and inexpensive lignin-blocker based on the molecular force measurements through the combined effects of electrostatic, cation-π, and hydrophobic interactions, which significantly improved the enzymatic hydrolysis efficiencies of cellulose in pretreated lignocellulosic substrates. Our results offer quantitative information on the fundamental understanding of the lignin-cellulase interaction mechanism. Such unraveled nanomechanics provides new insights into the development of advanced biotechnologies for addressing the nonproductive adsorption of lignin to cellulase, with great implications on improving the economics of lignocellulosic biorefinery.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acs.biomac.1c00140DOI Listing
April 2021