bluuebunny/crossref_metadata_2025_split huggingface dataset:
Enzymatic Tailoring in Luzopeptin Biosynthesis Involves Cytochrome P450‐Mediated Carbon–Nitrogen Bond Desaturation for Hydrazone Formation
Authors: Shi Xinjie , Huang Liming , Song Kaihui , Zhao Guiyun , Liu Yu , Lv Longxian , Du Yi‐Ling 
Published: June 2021

AbstractLuzopeptins and related decadepsipeptides are bisintercalator nonribosomal peptides featuring rare acyl‐substituted tetrahydropyridazine‐3‐carboxylic acid (Thp) subunits that are critical to their biological activities. Herein, we reconstitute the biosynthetic tailoring pathway in luzopeptin A biosynthesis through in vivo genetic and in vitro biochemical approaches. Significantly, we revealed a multitasking cytochrome P450 enzyme that catalyzes four consecutive oxidations including the highly unusual carbon–nitrogen bond desaturation, forming the hydrazone‐bearing 4‐OH‐Thp residues. Moreover, we identified a membrane‐bound acyltransferase that likely mediates the subsequent O‐acetylation extracellularly, as a potential self‐protective strategy for the producer strain. Further genome mining of novel decadepsipeptides and an associated P450 enzyme have provided mechanistic insights into the P450‐mediated carbon–nitrogen bond desaturation. Our results not only reveal the molecular basis of pharmacophore formation in bisintercalator decadepsipeptides, but also expand the catalytic versatility of P450 family enzymes.
Cobalt‐Phthalocyanine‐Derived Molecular Isolation Layer for Highly Stable Lithium Anode
Authors: Dai Hongliu , Dong Jing , Wu Mingjie , Hu Qingmin , Wang Dongniu , Zuin Lucia , Chen Ning , Lai Chao , Zhang Gaixia , Sun Shuhui 
Published: June 2021

AbstractThe uneven consumption of anions during the lithium (Li) deposition process triggers a space charge effect that generates Li dendrites, seriously hindering the practical application of Li‐metal batteries. We report on a cobalt phthalocyanine electrolyte additive with a planar molecular structure, which can be tightly adsorbed on the Li anode surface to form a dense molecular layer. Such a planar molecular layer cannot only complex with Li ions to reduce the space charge effect, but also suppress side reactions between the anode and the electrolyte, producing a stable solid electrolyte interphase composed of amorphous lithium fluoride (LiF) and lithium carbonate (LiCO3), as verified by X‐ray absorption near‐edge spectroscopy. As a result, the Li|Li symmetric cell exhibits excellent cycling stability above 700 h under a high plating capacity of 3 mAh cm−2. Moreover, the assembled Li|lithium iron phosphate (LiFePO4, LFP) full‐cell can also deliver excellent cycling over 200 cycles under lean electrolyte conditions (3 μL mg−1).
Biomimetic Iron Complex Achieves TET Enzyme Reactivity**
Authors: Schmidl David , Jonasson Niko S. W. , Korytiaková Eva , Carell Thomas , Daumann Lena J. 
Published: June 2021

AbstractThe epigenetic marker 5‐methyl‐2′‐deoxycytidine (5mdC) is the most prevalent modification to DNA. It is removed inter alia via an active demethylation pathway: oxidation by Ten‐Eleven Translocation 5‐methyl cytosine dioxygenase (TET) and subsequent removal via base excision repair or direct demodification. Recently, we have shown that the synthetic iron(IV)‐oxo complex [FeIV(O)(Py5Me2H)]2+ (1) can serve as a biomimetic model for TET by oxidizing the nucleobase 5‐methyl cytosine (5mC) to its natural metabolites. In this work, we demonstrate that nucleosides and even short oligonucleotide strands can also serve as substrates, using a range of HPLC and MS techniques. We found that the 5‐position of 5mC is oxidized preferably by 1, with side reactions occurring only at the strand ends of the used oligonucleotides. A detailed study of the reactivity of 1 towards nucleosides confirms our results; that oxidation of the anomeric center (1′) is the most common side reaction.
Understanding and Engineering the Stereoselectivity of Humulene Synthase
Authors: Schotte Carsten , Lukat Peer , Deuschmann Adrian , Blankenfeldt Wulf , Cox Russell J. 
Published: June 2021

AbstractThe non‐canonical terpene cyclase AsR6 is responsible for the formation of 2E,6E,9E‐humulene during the biosynthesis of the tropolone sesquiterpenoid (TS) xenovulene A. The structures of unliganded AsR6 and of AsR6 in complex with an in crystallo cyclized reaction product and thiolodiphosphate reveal a new farnesyl diphosphate binding motif that comprises a unique binuclear Mg2+‐cluster and an essential K289 residue that is conserved in all humulene synthases involved in TS formation. Structure‐based site‐directed mutagenesis of AsR6 and its homologue EupR3 identify a single residue, L285/M261, that controls the production of either 2E,6E,9E‐ or 2Z,6E,9E‐humulene. A possible mechanism for the observed stereoselectivity was investigated using different isoprenoid precursors and results demonstrate that M261 has gatekeeping control over product formation.
Structural Basis for Isomerization Reactions in Fungal Tetrahydroxanthone Biosynthesis and Diversification
Authors: Yang Jiali , Mori Takahiro , Wei Xingxing , Matsuda Yudai , Abe Ikuro 
Published: June 2021

AbstractThe novel isomerase NsrQ, from Aspergillus novofumigatus, is a key enzyme in the biosynthesis of fungal tetrahydroxanthones and is responsible for dearomatizing cyclization to provide a tetrahydroxanthone scaffold. NsrQ catalyzes a two‐step isomerization reaction, involving the isomerization of allylic alcohol and subsequent inversion of configuration at the methyl group. We report on the biochemical and structural characterizations of NsrQ, and its homologue Dcr3, from Diaporthe longicolla. The crystal structures of NsrQ and Dcr3 revealed their similar overall structures, with a cone‐shaped α+β barrel fold, to those of the nuclear transport factor 2‐like superfamily enzymes. Furthermore, the structures of Dcr3 and NsrQ variants complexed with substrate analogues and the site‐directed mutagenesis studies identified the catalytic residues and the important hydrophobic residues in shaping the active site pocket for substrate binding. These enzymes thus utilize Glu and His residues as acid‐base catalysts. Based on these observations, we proposed a detailed reaction mechanism for NsrQ‐catalyzed isomerization reactions.
A comparison of most to least prompting, no‐no prompting and responsive prompt delay procedures
Authors: Foran‐Conn Denise , Hoerger Marguerite , Kelly Eimear , R. Cross Richard , Jones Serena , Walley Hannah , Firth Lauren 
Published: June 2021

AbstractDiscrete trial training is a commonly used to teach children with autism spectrum disorder and related intellectual disabilities. A number of prompting and error correction strategies can be implemented when using discrete trial training. These strategies need to be effective and efficient. We compared a novel procedure, responsive prompt delay, to most to least prompting and no‐no prompting. A parallel treatments design, nestled in a modified multiple probe design (Horner & Baer, 1978), was used to compare the three procedures with three participants. The responsive prompt delay procedure was at least as effective as the most to least prompting and no‐no prompting procedures for three participants; the time required for each participant to master the skills was variable across procedures.
Enhanced Accumulation of Betulinic Acid in Transgenic Hairy Roots of Senna obtusifolia Growing in the Sprinkle Bioreactor and Evaluation of Their Biological Properties in Various Biological Models
Authors: Kowalczyk Tomasz , Sitarek Przemysław , Toma Monika , Rijo Patricia , Domínguez‐Martín Eva , Falcó Irene , Sánchez Gloria , Śliwiński Tomasz 
Published: June 2021

AbstractBetulinic acid, which is found in transgenic roots of Senna obtusifolia (L.) H.S.Irwin & Barneby, is a pentacyclic triterpene with distinctive pharmacological activities. In this study, we report the differences in the content of betulinic acid and selected anthraquinones in transgenic S. obtusifolia hairy roots with overexpression of the PgSS1 gene (SOPSS2 line) and in transformed hairy roots without this genetic construct (SOA41 line). Both hairy root lines grew in 10 L sprinkle bioreactor. Additionally, the extracts obtained from this plant material were used for biological tests. Our results demonstrated that the SOPSS2 hairy root cultures from the bioreactor showed an increase in the content of betulinic acid (38.125 mg/g DW), compared to the SOA41 hairy root line (4.213 mg/g DW). Biological studies have shown a cytotoxic and antiproliferative effect on U‐87MG glioblastoma cells, and altering the level of apoptotic proteins (Bax, p53, Puma and Noxa). Antimicrobial properties were demonstrated for both tested extracts, with a stronger effect of SOPSS2 extract. Moreover, both extracts showed moderate antiviral properties on norovirus surrogates.
Fine‐Tuning the Bicyclo[3.3.1]nona‐2,6‐diene Ligands: Second Generation 4,8‐Substituted Dienes for Rh‐Catalyzed Asymmetric 1,4‐Addition Reactions
Authors: Bieliūnas Vidmantas , Stončius Sigitas 
Published: June 2021

AbstractDesign and synthesis of the second generation C2‐symmetric 4,8‐endo,endo‐bis(alkoxy) bicyclo[3.3.1]nona‐2,6‐diene ligands possessing additional 4,8‐exo,exo substituents is reported. The 4,8‐exo,exo groups provide a further element for fine‐tuning of the ligand structure by enforcing conformational rigidity of the 4,8‐endo,endo side chains. Such tetrasubstituted bicyclo[3.3.1]nona‐2,6‐dienes were employed as steering ligands in the rhodium‐catalyzed arylation of cyclic enones with arylboronic acids, providing the corresponding 1,4‐addition products in good to excellent yields (69–99 %) and enantioselectivities up to 99 % ee.
Germinability of annual bluegrass seed during spring in the Eastern United States
Authors: Carroll Devon E. , Brosnan James T. , McCurdy James D. , De Castro Edicarlos B. , Patton Aaron J. , Liu Wenwen , Kaminski John E. , Tang Kaiyuan , McCullough Patrick E. , Westbury David 
Published: June 2021

AbstractSoil seedbank management via collecting clippings may be a means of combatting herbicide resistance in annual bluegrass (Poa annua L.) by minimizing recruitment from the deposition of viable seed into the soil. Our objective was to assess the germinability of annual bluegrass seed in spring to determine when collecting clippings would be most impactful. Research was conducted across 2019 and 2020 in five locations: Knoxville, TN; Starkville, MS; Griffin, GA; West Lafayette, IN; and University Park, PA. Annual bluegrass seed was harvested every 100 growing degree‐days (GDD0C; base 0 °C with accumulation beginning on 1 January each year from 400 to 1,100 GDD0C. Seeds from each harvest timing were placed on moistened blotter paper in petri dishes and randomized in a growth chamber set to a 77:68 °F and 8:16 h light–dark cycle. Germination was assessed every 3 d until 21 d of incubation. Cumulative germination percentage after 21 d of incubation increased at research locations in northern latitudes. In Tennessee, germination was greatest from 600 to 900 GDD0C. In Indiana, germination did not exceed 50% until 600 GDD0C and increased with GDD0C accumulation. Clippings should not be collected until at least 600 GDD0C in these locations. In Pennsylvania, little variation existed among GDD0C harvest times, indicating that clipping collection may be a valuable practice any time mature seedheads are present. Turfgrass managers should consider geographic location when selecting a time to implement clipping collections and will probably need to conduct multiple clipping collection events.
Materials Development in Hybrid Zinc‐Ion Capacitors
Authors: Jagadale Ajay Dattu , Rohit Ravichandran Chitra , Shinde Surendra Krushna , Kim Dae‐Young 
Published: June 2021

AbstractHigh‐performance energy storage devices have an exceptional role in modern applications such as green transportation, consumer electronics and electrical systems. Recently, the hybrid supercapacitor has gained great interest among researchers that adopt a combination of capacitive and battery‐type electrodes to increase the energy density without sacrificing the power performance. Different types of hybrid energy storage devices have been reported recently including lithium‐ion capacitor (LIC), sodium‐ion capacitor (NIC) and potassium‐ion capacitor (KIC). However, these devices are based on alkali metals such as Li, Na and K which are extremely reactive and consistently used with flammable organic electrolytes that intensify serious safety issues. Hybrid devices based on multivalent ions including Mg2+, Ca2+, Al3+ and Zn2+ have achieved considerable attraction due to their rapid charge transfer kinetics and high capacity as well as energy density. Herein, we reviewed the recent developments in the anode and cathode materials of Zinc ion hybrid capacitors (ZICs). The design, construction and working of supercapacitor (SC), Zinc ion battery (ZIB) and ZIC have been discussed along with their charge storage mechanism. Finally, based on the published work, our views on future developmental opportunities have been discussed.
The identity crisis of ecological diversity
Authors: Miriti Maria N. 
Published: June 2021

AbstractDeveloping the ecological scientist mindset among underrepresented students in ecology fields(Bowser and Cid, this Forum) provides timely and compelling strategies to broaden inclusion in ecology and environmental biology. Chronic underrepresentation of minorities in ecology and environmental disciplines (EE) is a crisis that is surprising to many, and even more surprising that, for African‐Americans, this underrepresentation is more severe compared to other STEM disciplines. It is beyond irony that a discipline that values diversity as a cornerstone of ecological practice continues to struggle to achieve diversity in the ranks of its practitioners.
Consequences of underexplored variation in biodiversity indices used for land‐use prioritization
Authors: Crawford Christopher L. , Estes Lyndon D. , Searchinger Timothy D. , Wilcove David S. 
Published: June 2021

AbstractFor biodiversity protection to play a persuasive role in land‐use planning, conservationists must be able to offer objective systems for ranking which natural areas to protect or convert. Representing biodiversity in spatially explicit indices is challenging because it entails numerous judgments regarding what variables to measure, how to measure them, and how to combine them. Surprisingly few studies have explored this variation. Here, we explore how this variation affects which areas are selected for agricultural conversion by a land‐use prioritization model designed to reduce the biodiversity losses associated with agricultural expansion in Zambia. We first explore the similarity between model recommendations generated by three recently published composite indices and a commonly used rarity‐weighted species richness metric. We then explore four underlying sources of ecological and methodological variation within these and other approaches, including different terrestrial vertebrate taxonomic groups, different species‐richness metrics, different mathematical methods for combining layers, and different spatial resolutions of inputs. The results generated using different biodiversity approaches show very low spatial agreement regarding which areas to convert to agriculture. There is little overlap in areas identified for conversion using previously published indices (mean Jaccard similarity, Jw, between 0.3 and 3.7%), different taxonomic groups (5.0% < mean Jw < 13.5%), or different measures of species richness (15.6% < mean Jw < 33.7%). Even with shared conservation goals, different methods for combining layers and different input spatial resolutions still produce meaningful, though smaller, differences among areas selected for conversion (40.9% < mean Jw < 67.5%). The choice of taxonomic group had the largest effect on conservation priorities, followed by the choice of species richness metric, the choice of combination method, and finally the choice of spatial resolution. These disagreements highlight the challenge of objectively representing biodiversity in land‐use planning tools, and present a credibility challenge for conservation scientists seeking to inform policy making. Our results suggest an urgent need for a more consistent and transparent framework for designing the biodiversity indices used in land‐use planning, which we propose here.
Effects of inspiratory muscle training combined with aerobic exercise training on neurovascular control in chronic heart failure patients
Authors: Trevizan Patricia F. , Antunes‐Correa Ligia M. , Lobo Denise M.L. , Oliveira Patricia A. , de Almeida Dirceu R. , Abduch Maria Cristina D. , Mathias Junior Wilson , Hajjar Ludhmila Abrahão , Kalil Filho Roberto , Negrão Carlos Eduardo 
Published: June 2021

AbstractAimsWe tested the hypothesis that the effects of combined inspiratory muscle training and aerobic exercise training (IMT + AET) on muscle sympathetic nerve activity (MSNA) and forearm blood flow in patients with heart failure with reduced ejection fraction are more pronounced than the effects of AET alone.Methods and resultsPatients aged 30–70 years, New York Heart Association Functional Class II‐III, and left ventricular ejection fraction ≤40% were randomly assigned to four groups: IMT (n = 11), AET (n = 12), IMT + AET (n = 9), and non‐training (NT; n = 10). MSNA was recorded using microneurography. Forearm blood flow was measured by venous occlusion plethysmography and inspiratory muscle strength by maximal inspiratory pressure. IMT consisted of 30 min sessions, five times a week, for 4 months. Moderate AET consisted of 60 min sessions, three times a week for 4 months. AET (−10 ± 2 bursts/min, P = 0.03) and IMT + AET (−13 ± 4 bursts/min, P = 0.007) reduced MSNA. These responses in MSNA were not different between AET and IMT + AET groups. IMT (0.22 ± 0.08 mL/min/100 mL, P = 0.03), AET (0.27 ± 0.09 mL/min/100 mL, P = 0.01), and IMT + AET (0.35 ± 0.12 mL/min/100 mL, P = 0.008) increased forearm blood flow. No differences were found between groups. AET (3 ± 1 mL/kg/min, P = 0.006) and IMT + AET (4 ± 1 mL/kg/min, P = 0.001) increased peak oxygen consumption. These responses were similar between these groups. IMT (20 ± 3 cmH2O, P = 0.005) and IMT + AET (18 ± 3 cmH2O, P = 0.01) increased maximal inspiratory pressure. No significant changes were observed in the NT group.ConclusionsIMT + AET causes no additive effects on neurovascular control in patients with heart failure with reduced ejection fraction compared with AET alone. These findings may be, in part, because few patients had inspiratory muscle weakness.
Temporal changes of cardiac acoustic biomarkers and cardiac function in acute decompensated heart failure
Authors: Shitara Jun , Kasai Takatoshi , Murata Nobutaka , Yamakawa Nobuhide , Yatsu Shoichiro , Murata Azusa , Matsumoto Hiroki , Kato Takao , Suda Shoko , Matsue Yuya , Naito Ryo , Hiki Masaru , Daida Hiroyuki 
Published: June 2021

AbstractAimsRelationships between cardiac acoustic biomarkers (CABs) measured by acoustic cardiography and clinical outcomes have been reported in heart failure (HF) patients. However, no studies have investigated the temporal change of CABs and the corresponding changes in HF status. The purpose of this study was to assess whether the temporal changes of CABs in patients with acute decompensated heart failure (ADHF) reflect changes in cardiac function and status.Methods and resultsSixty ADHF patients were enrolled prospectively. CABs and echocardiography data were collected at admission, before discharge, and at the first clinic visit. CABs included electromechanical activation time (EMAT); the time interval from Q wave onset on electrocardiography to the first heart sound (S1), QoS2; the time interval from Q wave onset on electrocardiography to the second heart sound (S2); and third heart sound (S3) and fourth heart sound (S4) intensities, defined as the peak‐to‐peak amplitudes of S3 and S4. EMATc (EMAT/RR) (P = 0.001), S3 intensity (P < 0.001), and S4 intensity (P < 0.001) were significantly decreased, and QoS2 (P = 0.005) was significantly increased from admission to discharge. The change in S3 intensity was significantly correlated with that of E/A (ρ = 0.571, P < 0.001), and the extended QoS2 was also significantly correlated with the increase in the stroke volume index (ρ = 0.383, P = 0.004).ConclusionsSome CABs in ADHF patients changed significantly in the normal direction throughout the treatment course and could be useful biomarkers in ADHF management.
An Update on Cyclohepta[b]indoles
Authors: Gierok Jan , Benedix Lars , Hiersemann Martin 
Published: June 2021

AbstractThe cyclohepta[b]indole scaffold constitutes a salient structural motif in natural products as well as in men‐made pharmaceutically active ingredients. Cyclohepta[b]indoles consist of an indole nucleus fused to a seven‐membered carbacycle. Interest in cyclohepta[b]indole chemistry originates from natural product chemistry and medicinal chemistry. The chemistry of cyclohepta[b]indole‐based organic functional materials may be a research area with some potential. The state of the art of cyclohepta[b]indoloid chemism has been comprehensively and scholarly summarized by the leading review article of Stempel and Gaich in 2016. Following this lead, our Minireview covers the literature from 2016 to 2021.
Secondary‐flow‐aided single‐train elastic‐inertial focusing in low elasticity viscoelastic fluids
Authors: Xiang Nan , Wang Silin , Ni Zhonghua 
Published: June 2021

AbstractElastic‐inertial focusing has attracted increasing interest in recent years due to the three‐dimensional (3D) single‐train focusing ability it offers. However, multi‐train focusing, instead of single‐train focusing, was observed in viscoelastic fluids with low elasticity as a result of the competition between inertia effect and viscoelasticity effect. To address this issue, we employed the secondary flow to facilitate single‐train elastic‐inertial focusing in low elasticity viscoelastic fluids. A three‐section contraction‐expansion channel was designed to induce the secondary flow to pinch the multiplex focusing trains into a single one exactly at the channel centerline. After demonstrating the focusing process and mechanism in our device, we systematically explored and discussed the effects of particle diameter, operational flow rate, polymer concentration, and channel dimension on particle focusing performances. Our device enables single‐train focusing of particles in viscoelastic fluids with low elasticity, and offers advantages of planar single‐layer structure, and sheathless, external‐field free operation.
Exploratory analysis on the association of mental health disorders with in‐hospital postoperative complications and mortality in head and neck cancer surgery
Authors: Gao Jeff , Tseng Christopher C. , Barinsky Gregory L. , Povolotskiy Roman , Grube Jordon G. , Baredes Soly , Park Richard Chan Woo 
Published: June 2021

AbstractBackgroundThe objective was to assess the association of mental health disorders with in‐hospital complication and mortality rates in patients undergoing head and neck cancer surgery.MethodsIn this exploratory retrospective study, the Nationwide Inpatient Sample was queried from 2003 to 2014 for all patients with a diagnosis of head and neck cancer who underwent surgery. Univariate cross‐tabulation, logistic regression, and propensity score matching (PSM) were used to compare demographics, procedure‐related variables, and in‐hospital postoperative complications and mortality between patients with and without selected comorbid mental health disorders.ResultsOf 39 600 included patients, 3390 (8.6%) had a selected comorbid mental health disorder diagnosis. After PSM, patients with selected mental health disorders had increased risk of overall medical complications on multivariable analysis (OR 1.28 [CI 1.12–1.46], P < 0.001) but not overall surgical complications or mortality.ConclusionsPatients with a mental health disorder diagnosis have increased risk of in‐hospital medical, certain surgical, and total complications.