UCHL1 Impairs Periodontal Ligament Stem Cell Osteogenesis in Periodontitis

Periodontitis comprises a series of inflammatory responses resulting in alveolar bone loss. The suppression of osteogenesis of periodontal ligament stem cells (PDLSCs) by inflammation is responsible for impaired alveolar bone regeneration, which remains an ongoing challenge for periodontitis therapy. Ubiquitin C-terminal hydrolase L1 (UCHL1) belongs to the family of deubiquitinating enzymes, which was found to play roles in inflammation previously. In this study, the upregulation of UCHL1 was identified in inflamed PDLSCs isolated from periodontitis patients and in healthy PDLSCs treated with tumor necrosis factor-α or interleukin-1β, and the higher expression level of UCHL1 was accompanied with the impaired osteogenesis of PDLSCs. Then UCHL1 was inhibited in PDLSCs using the lentivirus or inhibitor, and the osteogenesis of PDLSCs suppressed by inflammation was rescued by UCHL1 inhibition. Mechanistically, the negative effect of UCHL1 on the osteogenesis of PDLSCs was attributable to its negative regulation of mitophagy-dependent bone morphogenetic protein 2/Smad signaling pathway in periodontitis-associated inflammation. Furthermore, a ligature-induced murine periodontitis model was established, and the specific inhibitor of UCHL1 was administrated to periodontitis mice. The histological results showed increased active osteoblasts on alveolar bone surface and enhanced alveolar bone regeneration when UCHL1 was inhibited in periodontitis mice. Besides, the therapeutic effects of UCHL1 inhibition on ameliorating periodontitis were verified, as indicated by less bone loss and reduced inflammation. Altogether, our study proved UCHL1 to be a key negative regulator of the osteogenesis of PDLSCs in periodontitis and suggested that UCHL1 inhibition holds promise for alveolar bone regeneration in periodontitis treatment.

Constraints on Heavy Decaying Dark Matter from 570 Days of LHAASO Observations

The kilometer square array (KM2A) of the large high altitude air shower observatory (LHAASO) aims at surveying the northern γ-ray sky at energies above 10 TeV with unprecedented sensitivity. γ-ray observations have long been one of the most powerful tools for dark matter searches, as, e.g., high-energy γ rays could be produced by the decays of heavy dark matter particles. In this Letter, we present the first dark matter analysis with LHAASO-KM2A, using the first 340 days of data from 1/2-KM2A and 230 days of data from 3/4-KM2A. Several regions of interest are used to search for a signal and account for the residual cosmic-ray background after γ/hadron separation. We find no excess of dark matter signals, and thus place some of the strongest γ-ray constraints on the lifetime of heavy dark matter particles with mass between 10^{5} and 10^{9}  GeV. Our results with LHAASO are robust, and have important implications for dark matter interpretations of the diffuse astrophysical high-energy neutrino emission.

FAM83A promotes the progression and metastasis of human pancreatic neuroendocrine tumors by inducing the epithelial-mesenchymal transition via the PI3K/AKT and ERK pathways

PURPOSE

Family with sequence similarity 83, member A (FAM83A) has been reported to play an important role in cancer progression and metastasis. The purpose of this study was to clarify the role and mechanism of FAM83A in pancreatic neuroendocrine tumors (PanNETs).

METHODS

PanNET specimens and adjacent nontumor pancreatic tissues obtained from 68 patients who underwent curative surgery for PanNETs were assessed for FAM83A expression using immunochemical staining. The relationships between FAM83A expression, clinicopathological parameters and prognosis were statistically analyzed. PanNET cell lines were used to study the role of FAM83A in the progression and metastasis of PanNETs in vitro and in vivo.

RESULTS

FAM83A was overexpressed in PanNET specimens compared with adjacent nontumor tissues. Furthermore, FAM83A expression was closely associated with lymph node metastasis (P = 0.02), perineural invasion (P = 0.001), WHO classification (P = 0.039), AJCC stage (P = 0.01) and shorter disease-free survival in patients with PanNETs (P < 0.001). FAM83A overexpression effectively promoted PanNET cell proliferation, migration, invasion and growth both in vitro and in vivo, whereas FAM83A inhibition exerted the opposite effects. Subsequent mechanistic investigations revealed that FAM83A promotes the progression and metastasis of PanNETs by inducing epithelial-mesenchymal transition (EMT) via the PI3K/AKT and ERK pathways.

CONCLUSIONS

FAM83A plays an important role in the progression and metastasis of PanNET by inducing the EMT via the activation of the ERK and PI3K/AKT pathways and may serve as a valuable molecular target in PanNET treatment.

A, Barbano A, Barwick SW, Bastian B, Basu V, Baur S, Bay R, Beatty JJ, Becker KH, Becker Tjus J, Bellenghi C, BenZvi S, Berley D, Bernardini E, Besson DZ, Binder G, Bindig D, Blaufuss E, Blot S, Boddenberg M, Bontempo F, Borowka J, Böser S, Botner O, Böttcher J, Bourbeau E, Bradascio F, Braun J, Brinson B, Bron S, Brostean-Kaiser J, Browne S, Burgman A, Burley RT, Busse RS, Campana MA, Carnie-Bronca EG, Chen C, Chen Z, Chirkin D, Choi K, Clark BA, Clark K, Classen L, Coleman A, Collin GH, Conrad JM, Coppin P, Correa P, Cowen DF, Cross R, Dappen C, Dave P, De Clercq C, DeLaunay JJ, Delgado López D, Dembinski H, Deoskar K, Desai A, Desiati P, de Vries KD, de Wasseige G, de With M, DeYoung T, Diaz A, Díaz-Vélez JC, Dittmer M, Dujmovic H, Dunkman M, DuVernois MA, Dvorak E, Ehrhardt T, Eller P, Engel R, Erpenbeck H, Evans J, Evenson PA, Fan KL, Fazely AR, Fedynitch A, Feigl N, Fiedlschuster S, Fienberg AT, Filimonov K, Finley C, Fischer L, Fox D, Franckowiak A, Friedman E, Fritz A, Fürst P, Gaisser TK, Gallagher J, Ganster E, Garcia A, Garrappa S, Gerhardt L, Ghadimi A, Glaser C, Glauch T, Glüsenkamp T, Goldschmidt A, Gonzalez JG, Goswami S, Grant D, Grégoire T, Griswold S, Günther C, Gutjahr P, Haack C, Hallgren A, Halliday R, Halve L, Halzen F, Ha Minh M, Hanson K, Hardin J, Harnisch AA, Haungs A, Hebecker D, Helbing K, Henningsen F, Hettinger EC, Hickford S, Hignight J, Hill C, Hill GC, Hoffman KD, Hoffmann R, Hokanson-Fasig B, Hoshina K, Huang F, Huber M, Huber T, Hultqvist K, Hünnefeld M, Hussain R, Hymon K, In S, Iovine N, Ishihara A, Jansson M, Japaridze GS, Jeong M, Jin M, Jones BJP, Kang D, Kang W, Kang X, Kappes A, Kappesser D, Kardum L, Karg T, Karl M, Karle A, Katz U, Kauer M, Kellermann M, Kelley JL, Kheirandish A, Kin K, Kintscher T, Kiryluk J, Klein SR, Koirala R, Kolanoski H, Kontrimas T, Köpke L, Kopper C, Kopper S, Koskinen DJ, Koundal P, Kovacevich M, Kowalski M, Kozynets T, Kun E, Kurahashi N, Lad N, Lagunas Gualda C, Lanfranchi JL, Larson MJ, Lauber F, Lazar JP, Lee JW, Leonard K, Leszczyńska A, Li Y, Lincetto M, Liu QR, Liubarska M, Lohfink E, Lozano Mariscal CJ, Lu L, Lucarelli F, Ludwig A, Luszczak W, Lyu Y, Ma WY, Madsen J, Mahn KBM, Makino Y, Mancina S, Mariş IC, Martinez-Soler I, Maruyama R, Mase K, McElroy T, McNally F, Mead JV, Meagher K, Mechbal S, Medina A, Meier M, Meighen-Berger S, Micallef J, Mockler D, Montaruli T, Moore RW, Morse R, Moulai M, Naab R, Nagai R, Nahnhauer R, Naumann U, Necker J, Nguyen LV, Niederhausen H, Nisa MU, Nowicki SC, Nygren D, Obertacke Pollmann A, Oehler M, Oeyen B, Olivas A, O’Sullivan E, Pandya H, Pankova DV, Park N, Parker GK, Paudel EN, Paul L, Pérez de los Heros C, Peters L, Peterson J, Philippen S, Pieper S, Pittermann M, Pizzuto A, Plum M, Popovych Y, Porcelli A, Prado Rodriguez M, Price PB, Pries B, Przybylski GT, Raab C, Rack-Helleis J, Raissi A, Rameez M, Rawlins K, Rea IC, Rehman A, Reichherzer P, Reimann R, Renzi G, Resconi E, Reusch S, Rhode W, Richman M, Riedel B, Roberts EJ, Robertson S, Roellinghoff G, Rongen M, Rott C, Ruhe T, Ryckbosch D, Rysewyk Cantu D, Safa I, Saffer J, Sanchez Herrera SE, Sandrock A, Sandroos J, Santander M, Sarkar S, Sarkar S, Satalecka K, Schaufel M, Schieler H, Schindler S, Schmidt T, Schneider A, Schneider J, Schröder FG, Schumacher L, Schwefer G, Sclafani S, Seckel D, Seunarine S, Sharma A, Shefali S, Silva M, Skrzypek B, Smithers B, Snihur R, Soedingrekso J, Soldin D, Spannfellner C, Spiczak GM, Spiering C, Stachurska J, Stamatikos M, Stanev T, Stein R, Stettner J, Steuer A, Stezelberger T, Stokstad R, Stürwald T, Stuttard T, Sullivan GW, Taboada I, Ter-Antonyan S, Tilav S, Tischbein F, Tollefson K, Tönnis C, Toscano S, Tosi D, Trettin A, Tselengidou M, Tung CF, Turcati A, Turcotte R, Turley CF, Twagirayezu JP, Ty B, Unland Elorrieta MA, Valtonen-Mattila N, Vandenbroucke J, van Eijndhoven N, Vannerom D, van Santen J, Verpoest S, Walck C, Watson TB, Weaver C, Weigel P, Weindl A, Weiss MJ, Weldert J, Wendt C, Werthebach J, Weyrauch M, Whitehorn N, Wiebusch CH, Williams DR, Wolf M, Woschnagg K, Wrede G, Wulff J, Xu XW, Yanez JP, Yoshida S, Yu S, Yuan T, Zhang Z, Zhelnin P. Evidence for neutrino emission from the nearby active galaxy NGC 1068

A supermassive black hole, obscured by cosmic dust, powers the nearby active galaxy NGC 1068. Neutrinos, which rarely interact with matter, could provide information on the galaxy’s active core. We searched for neutrino emission from astrophysical objects using data recorded with the IceCube neutrino detector between 2011 and 2020. The positions of 110 known gamma-ray sources were individually searched for neutrino detections above atmospheric and cosmic backgrounds. We found that NGC 1068 has an excess of 79 − 20 + 22 neutrinos at tera–electron volt energies, with a global significance of 4.2σ, which we interpret as associated with the active galaxy. The flux of high-energy neutrinos that we measured from NGC 1068 is more than an order of magnitude higher than the upper limit on emissions of tera–electron volt gamma rays from this source.

Search for Unstable Sterile Neutrinos with the IceCube Neutrino Observatory

We present a search for an unstable sterile neutrino by looking for a resonant signal in eight years of atmospheric ν_{μ} data collected from 2011 to 2019 at the IceCube Neutrino Observatory. Both the (stable) three-neutrino and the 3+1 sterile neutrino models are disfavored relative to the unstable sterile neutrino model, though with p values of 2.8% and 0.81%, respectively, we do not observe evidence for 3+1 neutrinos with neutrino decay. The best-fit parameters for the sterile neutrino with decay model from this study are Δm_{41}^{2}=6.7_{-2.5}^{+3.9}  eV^{2}, sin^{2}2θ_{24}=0.33_{-0.17}^{+0.20}, and g^{2}=2.5π±1.5π, where g is the decay-mediating coupling. The preferred regions of the 3+1+decay model from short-baseline oscillation searches are excluded at 90% C.L.

Association of usual walking with mortality in oldest old adults aged 85 years and older: a nationwide senior cohort study

Background

Current guidelines recommend moderate to vigorous intensity physical activity (MVPA) for health benefit in adults. However, it is difficult to meet the recommended minimum MVPA in “oldest old” aged over 85. Although walking is simple and easy exercise for oldest old, research on the association between walking and mortality in oldest old are lacking.

Purpose

To investigate the association between walking and the risk of all-cause and cardiovascular mortality among older adults aged 85 years and older.

Methods

7047 participants aged 85 or older underwent the Korean National Health Screening Program, including self-administered questionnaire for physical activity. Reported frequency per week of walking for at least 30 minutes increment was used to classify hours of walking per week. We computed multivariable-adjusted hazard ratios for walking and mutually adjusted for MVPA in relation to all-cause and cardiovascular mortality.

Results

The proportions of participants who engaged in walking, moderate- and vigorous-intensity physical activity were 42.5% (2996/7047), 14.7% (1037/7047) and 11.0% (773/7047), respectively. Only 7.6% (538/7047) of participants met the guidelines recommended minimum MVPA. Compared to inactive individuals, those who walked at least 1 hour per week had lower all-cause (HR 0.60 [95% CI, 0.50–0.74]) and cardiovascular mortality risk (HR 0.61 [95% CI, 0.42–0.89]). Walking 1 hour per week was still significant associated with reduction of risk for all-cause (HR 0.50 [95% CI, 0.40–0.61]) and cardiovascular mortality (HR 0.46 [95% CI, 0.30–0.70]) among participants who reported only walking without any MVPA.

Conclusions

1 hour a week of walking might be of benefit for all-cause and cardiovascular mortality in aged over 85 years, even without MVPA. Promoting walking may be a way to help oldest old avoid inactivity and encourage an active lifestyle for all-cause and cardiovascular mortality risk reduction.

Funding Acknowledgement

Type of funding sources: None.

Densification pretreatment triggers efficient methanogenic performance and robust microbial community during anaerobic digestion of corn stover

The recalcitrant characteristics of lignocellulosic waste and difficulties in biomass transportation and storage severely limit bioenergy production through anaerobic digestion (AD). In this study, Densifying Lignocellulosic biomass with Chemicals (DLC) pretreatment was developed to address these issues. The results showed that DLC treated corn stover (CS) reached a cumulative methane yield of as high as 224.30 mL/g VS (Volatile Solids), which was 59.27 % higher than that of un-treated. The reduced scum formation in the reactor, increased components consumption of solid phase, and higher organic biodegradability of liquid phase in AD of DLC treated CS enhanced methane yield. Microbial analysis indicated that DLC pretreatment affected the bacterial and methanogenic community structure, and a co-network with Comamonas and Methanobacterium, etc. as hub microbes was constructed. This study proposed a promising technology that could be potentially applied to industrial AD of lignocellulosic biomass.

A novel fermentation strategy for efficient xylose utilization and microbial lipid production in lignocellulosic hydrolysate

The sugar utilization efficiency and the tolerance of microorganism to inhibitors are essential for lipid production from lignocellulosic biomass. In this study, the sugar consumption and inhibitor tolerance characteristics of Trichosporon dermatis 32,903 were investigated. The results showed that the lipid yield on xylose was much lower than that on glucose, while these substrates exhibited comparative efficiency for cell growth. High inoculum size improved the tolerance of T. dermatis 32,903 to inhibitors. Based on these characteristics, sugar-targeted-utilization and cyclic fermentation strategy was developed. The tolerance of high inoculum size to inhibitors was utilized, glucose was targeted for lipid fermentation and xylose was targeted for cell growth. As a result, the lipid production efficiency was greatly enhanced. The lipid titer in hydrolysate of DLCA (Densifying Lignocellulosic biomass with Chemicals followed by Autoclave) pretreated rice straw was improved to as high as 38.4 g/L with lipid yield of 0.207 g/g consumed sugar.

Towards efficient enzymatic saccharification of pretreated lignocellulose: Enzyme inhibition by lignin-derived phenolics and recent trends in mitigation strategies

Lignocellulosic biorefinery based on its sugar-platform has been considered as an efficient strategy to replace fossil fuel-based refinery. In the bioconversion process, pretreatment is an essential step to firstly open up lignocellulose cell wall structure and enhance the accessibility of carbohydrates to hydrolytic enzymes. However, various lignin and/or carbohydrates degradation products (e.g. phenolics, 5-hydroxymethylfurfural, furfural) also generated during pretreatment, which severely inhibit the following enzymatic hydrolysis and the downstream fermentation process. Among them, the lignin derived phenolics have been considered as the most inhibitory compounds and their inhibitory effects are highly dependent on the source of biomass and the type of pretreatment strategy. Although liquid-solid separation and subsequent washing can remove the lignin derived phenolics and other inhibitors, this is undesirable in the realistic industrial application where the whole slurry of pretreated biomass need to be directly used in the hydrolysis process. This review summarizes the phenolics formation mechanism for various commonly applied pretreatment methods and discusses the key factors that affect the inhibitory effect of phenolics on cellulose hydrolysis. In addition, the recent achievements on the rational design of inhibition mitigation strategies to boost cellulose hydrolysis for sugar-platform biorefinery are also introduced. This review also provides guidance for rational design detoxification strategies to facilitate whole slurry hydrolysis which helps to realize the industrialization of lignocellulose biorefinery.

[Xenon post-conditioning protects against spinal cord ischemia-reperfusion injury in rats by downregulating mTOR pathway and inhibiting endoplasmic reticulum stress-induced neuronal apoptosis]

OBJECTIVE

The purpose of this study was to determine whether xenon post-conditioning affects mTOR signaling as well as endoplasmic reticulum stress (ERS)-apoptosis pathway in rats with spinal cord ischemia/reperfusion injury.

METHODS

Fifty male rats were randomized equally into sham-operated group (Sham group), I/R model group (I/R group), I/R model+ xenon post-conditioning group (Xe group), I/R model+rapamycin (a mTOR signaling pathway inhibitor) treatment group (I/R+ Rapa group), and I/R model + xenon post- conditioning with rapamycin treatment group (Xe + Rapa group).. In the latter 4 groups, SCIRI was induced by clamping the abdominal aorta for 85 min followed by reperfusion for 4 h. Rapamycin (or vehicle) was administered by daily intraperitoneal injection (4 mg/kg) for 3 days before SCIRI, and xenon post-conditioning by inhalation of 1∶1 mixture of xenon and oxygen for 1 h at 1 h after initiation of reperfusion; the rats without xenon post-conditioning were given inhalation of nitrogen and oxygen (1∶ 1). After the reperfusion, motor function and histopathologic changes in the rats were examined. Western blotting and real-time PCR were used to detect the protein and mRNA expressions of GRP78, ATF6, IRE1α, PERK, mTOR, p-mTOR, Bax, Bcl-2 and caspase-3 in the spinal cord.

RESULTS

The rats showed significantly lowered hind limb motor function following SCIRI (P < 0.01) with a decreased count of normal neurons, increased mRNA and protein expressions of GRP78, ATF6, IRE1α, PERK, and caspase-3, and elevated p-mTOR/mTOR ratio and Bax/Bcl-2 ratio (P < 0.01). Xenon post-conditioning significantly decreased the mRNA and protein levels of GRP78, ATF6, IRE1α, PERK and caspase-3 (P < 0.05 or 0.01) and reduced p-mTOR/mTOR and Bax/Bcl-2 ratios (P < 0.01) in rats with SCIRI; the mRNA contents and protein levels of GRP78 and ATF6 were significantly decreased in I/R+Rapa group (P < 0.01). Compared with those in Xe group, the rats in I/R+Rapa group and Xe+Rapa had significantly lowered BBB and Tarlov scores of the hind legs (P < 0.01), and caspase-3 protein level and Bax/Bcl-2 ratio were significantly lowered in Xe+Rapa group (P < 0.05 or 0.01).

CONCLUSION

By inhibiting ERS and neuronal apoptosis, xenon post- conditioning may have protective effects against SCIRI in rats. The mTOR signaling pathway is partially involved in this process.

Strong Constraints on Neutrino Nonstandard Interactions from TeV-Scale ν_{μ} Disappearance at IceCube

We report a search for nonstandard neutrino interactions (NSI) using eight years of TeV-scale atmospheric muon neutrino data from the IceCube Neutrino Observatory. By reconstructing incident energies and zenith angles for atmospheric neutrino events, this analysis presents unified confidence intervals for the NSI parameter ε_{μτ}. The best-fit value is consistent with no NSI at a p value of 25.2%. With a 90% confidence interval of -0.0041≤ε_{μτ}≤0.0031 along the real axis and similar strength in the complex plane, this result is the strongest constraint on any NSI parameter from any oscillation channel to date.

Rapid evolution and mechanism elucidation for efficient cellobiose-utilizing Saccharomyces cerevisiae through Synthetic Chromosome Rearrangement and Modification by LoxPsym-mediated Evolution

Lack of cellobiose utilization capability for many microorganisms results in carbon source waste in lignocellulosic biorefinery. In this study, genes for cellobiose transport and hydrolysis were introduced to Saccharomyces cerevisiae synV, a semi-synthetic yeast with an inducible SCRaMbLE (Synthetic Chromosome Rearrangement and Modification by LoxPsym-mediated Evolution) system incorporated into its chromosome V, endowing cellobiose utilization capability to this strain. Thereafter, two evolved strains with 98.1% and 79.2% improvement, respectively, in cellobiose utilization rate were obtained through induced SCRaMbLE. Further studies suggested that the enhanced cellobiose utilization capability directly correlated with copy number increases of introduced genes and some chromosome structural variations. In particular, it was experimentally demonstrated for the first time that deletion of redox stress related gene MXR1 and ATP conversion related gene ADK2 contributed to enhanced cellobiose conversion. Thereafter, the effectiveness of MXR1 and ADK2 deletions was demonstrated in artificial hydrolysate and rice straw hydrolysate, respectively.

Establishing a novel 3D printing bioinks system with recombinant human collagen

Bioinks are one of the key elements in realizing three-dimensional (3D) bioprinting. However, bioinks prepared from conventional collagen are hindered to their further applications due to concerns of collagen purity, unstable mechanical properties, and low solubility under neutralized conditions. This study aimed to develop a reliable UV-curable bioink system from a novel water-soluble recombinant human collagen (RHC). RHC was modified by methacrylic anhydride (MAA) and later crosslinked by 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDC)/N-hydroxysuccinimide (NHS) to obtain Pro-RHCMA. ¹H nuclear magnetic resonance (¹H NMR) confirmed the methacryloyl grafts, Fourier transform-infrared spectroscopy (FT-IR) illustrated the chemical crosslinking in producing the Pro-RHCMA. Internal morphology, mechanical properties and degradation of UV cured boinks were MAA and EDC/NHS modification-dependent. Photorheological properties and printability of the bioinks were determined. Cellular bioactivities were sustained within the printed bioinks, validating the bioinks biocompatibility in vitro. Finally, qRT-PCR revealed that the Pro-RHCMA bioinks provided a cell-friendly microenvironment for human umbilical vein endothelial cells (HUVECs) and human foreskin fibroblasts (HFFs), by supporting the expression of extracellular matrix (ECM) and angiogenesis-associated proteins, respectively. Taken together, this novel RHC-based bioink system shows great potential in tissue engineering and regenerative medicine.

Preparation of Chitosan/Recombinant Human Collagen-Based Photo-Responsive Bioinks for 3D Bioprinting

Collagen and chitosan are frequently used natural biomaterials in tissue engineering. However, most collagen is derived from animal tissue, with inconsistent quality and pathogen transmittance risks. In this context, we aimed to use a reliable Type-III recombinant human collagen (RHC) as an alternative biomaterial together with chitosan to develop novel photo-responsive bioinks for three-dimensional (3D) bioprinting. RHC was modified with methacrylic anhydride to obtain the RHC methacryloyl (RHCMA) and mixed with acidified chitosan (CS) to form composites CS-RHCMA. The characterizations demonstrated that the mechanical properties and the degradation of the bioinks were tunable by introducing the CS. The printabilities improved by adding CS to RHCMA, and various structures were constructed via extrusion-based 3D printing successfully. Moreover, in vitro tests confirmed that these CS-RHCMA bioinks were biocompatible as human umbilical vein endothelial cells (HUVECs) were sustained within the constructs post-printing. The results from the current study illustrated a well-established bioinks system with the potential to construct different tissues through 3D bioprinting.

Understanding the toxicity of lignin-derived phenolics towards enzymatic saccharification of lignocellulose for rationally developing effective in-situ mitigation strategies to maximize sugar production from lignocellulosic biorefinery

The lignin-derived phenolics are highly inhibitory toward lignocellulose enzymatic hydrolysis, while the relationship between phenolic structure and inhibitory effect is still not fully understood. In this study, the compositions of phenolics from dilute acid pretreated wheat straw were analyzed and their impact on cellulose hydrolysis was studied. With increase of pretreatment severity, more toxic phenolics were produced from lignin degradation reactions, which were the major contributor to the increased inhibitory effect of pretreatment hydrolysate towards cellulases. Through analyzing the relationship of phenolic structure and their inhibitory effect, a useful model was developed to predict the phenolics-caused inhibition by combining the indexes of electrophilicity and hydrophobicity. Further, through understanding the interactions between phenolics and cellulases, a novel biocomponent alleviator was rationally designed to block the phenolics-cellulase interactions, the degree of improvement of enzymatic hydrolysis reached as high as 135.8%. This study provides directions for developing more effective pretreatment and detoxification methods.

Deciphering the metabolic distribution of vanillin in Rhodococcus opacus during lignin valorization

Vanillin bioconversion is important for the biological lignin valorization. In this study, the obscure vanillin metabolic distribution in Rhodoccous opacus PD630 was deciphered by combining the strategies of intermediate detection, putative gene prediction, and target gene verification. The results suggest that approximately 10% (mol/mol) of consumed vanillin is converted to vanillic acid for further metabolism, and a large amount is converted to dead-end vanillyl alcohol in R. opacus PD630. Subsequently, five vanillin reductases were identified in R. opacus PD630, among which Pd630_LPD03722 product exhibited the greatest activity. With the detected metabolic distributions of vanillin, the conversion of vanillin to muconic acid was facilitated by deleting domestic vanillin reductase genes and introducing vanillin dehydrogenase from Sphingobium sp. SYK-6. Ultimately, the muconic acid yield from vanillin increased to 97.83% (mol/mol) from the initial 10% (mol/mol). Moreover, this study demonstrated the existence of vanillin reductases in Escherichia coli, Bacillus subtilis, and Corynebacterium glutamicum.

Effects of storage temperature and time on enzymatic digestibility and fermentability of Densifying lignocellulosic biomass with chemicals pretreated corn stover

A novel pretreatment, Densifying Lignocellulosic biomass with acidic/alkali Chemicals (DLC), was recently invented and owns unique advantages for biomass logistics and fermentation. The pretreatment was largely completed during biomass storage, which renders the storage conditions critical. In this study, the effects of storage temperature (-80 °C to 60 °C) and storage time (up to half a year) on the enzymatic digestibility and fermentability of DLC corn stover (CS) were investigated. DLC-CS containing calcium hydroxide(ch) showed increased enzymatic digestibility with increased storage temperature and time. High glucan conversions (>90%) and ethanol titers (e.g. 73.1 g/L) were achieved after regular steam autoclave of DLC(ch)-CS, without washing or detoxification. DLC-CS containing sulfuric acid(sa) was sensitive to storage conditions, and autoclaved DLC(sa)-CS reached the highest ethanol titer (66.6 g/L) when DLC(sa)-CS was stored at room temperature for 14 days. Results indicated that different ambient temperatures in different regions and seasons have a far-reaching impact on DLC-CS for bioconversion.

[Correlation between professional quality of life and social support of Chinese nurses: a meta-analysis]

Objective: To systematically evaluate the correlation between professional quality of life and social support of Chinese nurses based on Pearson and Spearman correlation coefficients. Methods: In databases including PubMed, Cochrane Library, CINAHL, Medline, CBM, CNKI、Wanfang, and other databases were searched by computer for the literatures on correlation between Chinese nurses' professional quality of life and social support from January 2005 to July 2020. The Chinese and English search terms are "nurse" "professional quality of life" "empathy satisfaction" "empathy fatigue" "professional quality of life" "ProQOL" "comparison satisfaction" "comparison fatigue" "social support" "competent social support" "SSRS" "PSSS", etc. Literatures were screened according to the inclusion and exclusion criteria. After evaluating quality and extracting data, meta-analysis was conducted using RevMan 5.3 software. Results: A total of 12 studies were included. The meta analysis showed that nurses' compassion satisfaction, burnout, secondary traumatic stress were related to social support, summary r were 0.35, -0.26 and -0.23 respectively. The correlation between compassion satisfaction and social support were increased with sample, the south was higher than the north, and comprehensive departments were higher than other departments (P<0.05) . The correlation between burnout and social support were increased with time and sample, and the south was higher than the north, oncology was higher than others, non-random sampling was higher than random sampling, using ProQOL and Perceived Social Support Scale (PSSS) was higher than Professional Quality of Life Scale (ProQOL) and Social Support Racting Scale (SSRS) (P<0.05) . The correlation coefficient between secondary traumatic stress and social support in oncology was higher than others, random sampling was higher than non-random sampling, using ProQOL and PSSS was higher than ProQOL and SSRS (P<0.05) . Conclusion: There is a positive and weak correlation between compassion satisfaction and social support, and a negative and weak correlation between burnout and secondary traumatic stress and social support. There are differences in different time, research design, region and department.