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The electrochemical advanced oxidation process (EAOP) has shown significant promise in the field of refractory organic wastewater treatment due to its high efficiency and environmentally friendly nature. In this study, Ti/Sb-SnO2 electrodes with varying proportions of Hf were prepared using the sol–gel method. The addition of Hf transformed the original collapsing and broken surface into a flat and regular surface. The results demonstrated that Ti/Sb-SnO2-Hf electrode doped with 6% Hf exhibited a higher oxygen evolution potential (OEP) and excellent stability. The OEP increased from 2.315 V without Hf-doping to 2.482 V, and the corresponding actual life was 321.05% higher than that without Hf. The current density (5–40 mA·cm−2), electrolyte concentration (0.02–0.2 mol·L−1), pH (3–11), and initial pollutant concentration (5–80 mg·L−1) were evaluated to confirm the tetracycline (TC) degradation characterization of Ti/Sb-SnO2-6%Hf electrodes. It was concluded that under the optimal degradation conditions, the removal rate of TC could reach 99.66% within 2 h. The degradation of TC follows first-order reaction kinetics. The oxidative degradation of TC was achieved through indirect oxidation, with ·OH playing a dominant role. TC's electrochemical oxidation degradation pathway has been proposed: Based on LC–MS results, three main pathways are speculated. During the electrocatalytic oxidation process, decarboxylation, deamidation, and ring-opening reactions occur under ·OH attack, producing intermediate compounds with m/z values of 427, 433, 350, 246, 461, 424, 330, 352, 309, 263, and 233. These intermediates are further oxidized to intermediate compounds with an m/z value of 218. This work introduces a new efficient anode electrochemical catalyst for the degradation of TC, providing a strategy for industrial applications. [ABSTRACT FROM AUTHOR]

To alleviate amino acid imbalances in fermented soybean meal as a replacement for fishmeal feeds, this study evaluated the effects of adding lysine (Lys), methionine (Met), and α-ketoglutaric acid (AKG) to fermented soybean meals for Chinese perch. Chinese perch (34 ± 3 g) were fed five diets for 66 days (fishmeal as the protein source of the basal diet [FM]; fermented soybean meal as a substitute for 30% fishmeal in the soybean meal diet [FSM]; addition of crystalline Lys and Met [AA]; addition of α-ketoglutaric acid [AKG]; and simultaneous addition of crystalline Lys, Met, and AKG [BA] to the soybean meal diet). At the end of the feeding trial, the FSM group had the highest feeding rate and the lowest weight gain rate among all the groups. The FM group had the highest protein retention and the lowest feed efficiency among the groups. The mRNA transcription level of genes related to the AMP-activating protein (AMPK) signaling pathway and amino acid response (AAR) signaling pathway (lkb1, atf4, and gcn2) were highest in the AA group (P < 0.05) but lower in the AKG and BA groups. In the AKG group, the mRNA transcription level of the gluconeogenesis pathway-related gene (pepck and g6pase) was significantly higher than that in the other four groups, but the mRNA transcription level of genes related to amino acid catabolism (gdh and ampd) was lower. Among all the groups, the FSM group had the lowest mRNA transcription level of genes associated with the mammalian target of rapamycin (mTOR) signaling pathway (mtor and s6k). These findings imply that the feeding rate of Chinese perch in the fermented soybean meal group was the highest, but the protein retention was the lowest, while the addition of Lys, Met, and AKG improved protein retention. In conclusion, the addition of AKG to fermented soybean meal as a fishmeal substitute reduced amino acid deamination, enhanced gluconeogenesis, and increased protein deposition, which contributed to the growth of Chinese perch, alleviated amino acid imbalances, and improved the feed utilization of Chinese perch. [ABSTRACT FROM AUTHOR]

The influence of conditions on the course of the reactions between 1,2-diaminoimidazole and N-arylmaleimides was studied. It was shown that, depending on the reaction conditions used, 10-amino-N-aryl-2-oxo-2,3,4,10-tetrahydropyrimido[1,2-a]benzimidazole-4-carboxamides or their deamination products, N-aryl-2-oxo-1,2,3,4-tetrahydropyrimido[1,2-a]benzimidazole-4-carboxamides, were formed. Virtual screening and molecular docking of this class of compounds allowed us to consider them as potential CRF1 receptor antagonists. [ABSTRACT FROM AUTHOR]

S-Adenosyl-l-homocysteine hydrolase (SAHH) reversibly cleaves S-adenosyl-l-homocysteine, the product of S-adenosyl-l-methionine-dependent methylation reactions. The conversion of S-adenosyl-l-homocysteine into adenosine and l-homocysteine plays an important role in the regulation of the methyl cycle. An alternative metabolic route for S-adenosyl-l-methionine regeneration in the extremophiles Methanocaldococcus jannaschii and Thermotoga maritima has been identified, featuring the deamination of S-adenosyl-l-homocysteine to S-inosyl-l-homocysteine. Herein, we report the structural characterisation of different archaeal SAHHs together with a biochemical analysis of various SAHHs from all three domains of life. Homologues deriving from the Euryarchaeota phylum show a higher conversion rate with S-inosyl-l-homocysteine compared to S-adenosyl-l-homocysteine. Crystal structures of SAHH originating from Pyrococcus furiosus in complex with SlH and inosine as ligands, show architectural flexibility in the active site and offer deeper insights into the binding mode of hypoxanthine-containing substrates. Altogether, the findings of our study support the understanding of an alternative metabolic route for S-adenosyl-l-methionine and offer insights into the evolutionary progression and diversification of SAHHs involved in methyl and purine salvage pathways. The biochemical characterisation of S-adenosyl-l-homocysteine hydrolases from all three domains of life supports the assumption that alternative routes for methyl metabolism coupled to purine salvage exist in some classes of Euryarchaeota. [ABSTRACT FROM AUTHOR]

Wheat gluten protein (WGP) is a fine-quality plant-based protein resource. However, as its unparalleled reticulation structure, the processing properties of WGP are extremely poor, limiting its application. To overcome these drawbacks, the purpose of this work was to embellish wheat gluten protein by three relatively novel and mainstream chemical modifications. The results showed the pH-shifting treatment altered the apparent morphology of protein, showing a uniform flocculent structure, leading to significant improvements in foaming capacity and emulsification property. After deamidation by acetic acid, the solubility of WGP was greatly improved (60.1%), which was nearly four times that of the control group (15.8%), and its foam stability was also significantly improved. The WGP had the highest thermal stability (deformation temperature up to 148 ℃) after TGase deamidation. These results indicate that the three modification methods enhance the functional characters of WGP in different aspects and expand its application potential. [ABSTRACT FROM AUTHOR]

The reaction of triflamide with allyl cyanide in benzonitrile and isobutyronitrile solutions in the presence of NBS has been studied. In both cases, the corresponding amidines formed by solvent insetion were obtained. In benzonitrile, depending on the reaction conditions, the isomeric N-(2-bromo-3-cyanopropyl)-N'-(triflyl)benzamidine and N-(1-bromo-3-cyanoprop-2-yl)-N'-(triflyl)benzamidine were obtained in various ratios. The reaction in isobutyronitrile resulted in the isolation of N-(2-bromo-3-cyanopropyl)-N'-(triflyl)isobutyramidine and the deamination product N-[3-cyano-1-(triflamido)propyl]isobutyramide. [ABSTRACT FROM AUTHOR]

This review is intended to elucidate the structure, biological activity, and use of various strategies for the synthesis of terphenyl and its derivatives from amines obtained by the Stevens rearrangement. The amine transformation is a domino reaction, including β-elimination of secondary amine with the formation of a conjugated dienyne, which forms a cyclic allene intermediate by an electrocyclic reaction. The subsequent 1,3- or 1,5-hydride shift rapidly produces the final compound. [ABSTRACT FROM AUTHOR]

To prepare a reliable method for predicting the properties of devulcanized rubbers a nitrile rubber (NBR) compound was prepared and masticated before vulcanization for 0, 30 and 60 min under mechanical stress to prepare NBRs with different molecular weights. The masticated samples were vulcanized at different accelerator contents to prepare damples with different crosslink densities. The physical/mechanical/thermal properties (i.e. crosslink density, tensile strength, modulus, modulus at 100 and 300% elongation, elongation at break, hardness, curing behavior and molecular weight) of the samples were experimentally evaluated. In the next step, the prepared samples were assumed as devulcanized NBRs that underwent chains scission (masticated samples) or crosslinks breakage (vulcanized at different accelerator contents). On this basis, hypothetical devulcanization routes were considered between each sample that underwent chains scission or crosslinks breakage. Based on the results, numerical relationships between the number of chains scission or crosslinks breakage and decrease in the properties were obtained. Finally, the numerical reationships were used to calculate the properties of the samples that underwent both of chains scission and crosslinks breakage. It was found that the calculated contents of hardness, modulus at 100% and molecular weight (MZ) using the prepared method were very close to the evaluated ones. [ABSTRACT FROM AUTHOR]

5-Methyl-2'-deoxycytidine (mC) at CpG sites plays a key role in the epigenetic gene regulation, cell differentiation, and carcinogenesis. Despite the importance of mC for normal cell function, CpG dinucleotides are known as mutagenesis hotspots. Deamination of mC yields T, causing C→T transitions. However, several recent studies demonstrated the effect of epigenetic modifications of C on the fidelity and efficiency of DNA polymerases and excision repair enzymes. The review summarizes the available data that indicate the existence of deamination-independent mechanisms of mutagenesis at CpG sites. [ABSTRACT FROM AUTHOR]

The mechanisms for the deamination reactions of 6-thioguanine (6-TG) with H2O, OH−, and OH−/H2O and for protonated 6-thioguanine (6-TGH+) with H2O have been studied by theoretical calculations. Six pathways, paths A–F, have been explored and relative energies, enthalpies, and Gibbs energies were calculated for each reaction path. Compared with the deamination reaction of 6-TG with H2O or 6-TGH+ with H2O, the deamination reaction of 6-TG with OH− shows a lower overall Gibbs energy of activation, indicating that the 6-TG deamination reaction is favorably to occur for the deprotonated form 6-TG− with H2O. With the assistance of an additional water molecule, the deamination reaction of 6-TG with OH−/H2O (path F) is found to be the most feasible pathway in gas phase and also in aqueous solution. The overall Gibbs energy of activation for path F in gas phase and in aqueous solution is 169.8 and 140.6 kJ mol−1 (SMD model), respectively, at the B3LYP/6–311++G(d,p) level of theory. [ABSTRACT FROM AUTHOR]

Adenosine-to-inosine tRNA-editing enzyme has been identified for more than two decades, but the study on its DNA editing activity is rather scarce. We show that amphioxus (Branchiostoma japonicum) ADAT2 (BjADAT2) contains the active site 'HxE-PCxxC' and the key residues for target-base-binding, and amphioxus ADAT3 (BjADAT3) harbors both the N-terminal positively charged region and the C-terminal pseudo-catalytic domain important for recognition of substrates. The sequencing of BjADAT2-transformed Escherichia coli genome suggests that BjADAT2 has the potential to target E. coli DNA and can deaminate at TCG and GAA sites in the E. coli genome. Biochemical analyses further demonstrate that BjADAT2, in complex with BjADAT3, can perform A-to-I editing of tRNA and convert C-to-U and A-to-I deamination of DNA. We also show that BjADAT2 preferentially deaminates adenosines and cytidines in the loop of DNA hairpin structures of substrates, and BjADAT3 also affects the type of DNA substrate targeted by BjADAT2. Finally, we find that C89, N113, C148 and Y156 play critical roles in the DNA editing activity of BjADAT2. Collectively, our study indicates that BjADAT2/3 is the sole naturally occurring deaminase with both tRNA and DNA editing capacity identified so far in Metazoa. An adenosine-to-inosine tRNA-editing deaminase ADAT2 from amphioxus (Branchiostoma japonicum) in complex with ADAT3 can perform A-to-I editing of tRNA and convert C-to-U and A-to-I deamination of DNA. [ABSTRACT FROM AUTHOR]

Transglutaminases (TGs) are a protein family that catalyzes isopeptide bond formation between glutamine and lysine residues of various proteins. There are eight TG isozymes in humans, and each is involved in diverse biological phenomena due to their characteristic distribution. Abnormal activity of TG1 and TG2, which are major TG isozymes, is believed to cause various diseases, such as ichthyosis and celiac disease. To elucidate TGs' mechanisms of action and develop new therapeutic strategies, it is essential to develop bioprobes that can specifically examine the activity of each TG isozyme, which has not been sufficiently studied. We previously have identified several substrate peptide sequences containing Gln residues for each isozyme and developed a method to detect isozyme-specific activities by incorporating a labeled substrate peptide into lysine residues of proteins. We prepared the fluorescein isothiocyanate (FITC)-labeled Gln substrate peptide (FITC-K5 and FITC-T26) and Rhodamine B-labeled Lys substrate peptide (RhoB-Kpep). Each TG reaction specifically cross-linked these probe pairs, and the proximity of FITC and Rhodamine B significantly decreased the fluorescence intensity of FITC depending on the concentration and reaction time of each TG. In this study, we developed a peptide-based biosensor that quickly and easily measures TG isozyme-specific activity. This probe is expected to be helpful in elucidating TG's physiological and pathological functions and in developing compounds that modulate TG activity. [ABSTRACT FROM AUTHOR]

In response to the high cost of activated persulfate technology, we have successfully prepared a composite catalyst N-rGO/Fe3O4 for reuse through magnetic separation. The degradation efficiency of 60 mg/L tetracycline (TC) reached 100% within 120 min under optimal conditions (c[peroxysulfate, PDS] = 2 mM; m(PDS):m(N-rGO/Fe3O4) = 1:6; pH = 3.0), while N-rGO/Fe3O4 maintained a high stability and reusability value in the cycling experiment. We found that in the N-rGO/Fe3O4 + PDS system, SO4−· and ·OH radicals were the most dominant reactants for TC decomposition, with non-radical reactions also contributing to TC degradation. Furthermore, we inferred four possible decomposition pathways of TC from the analysis of intermediates: (1) dehydration, (2) demethylation, (3) hydroxylation, and (4) deamidation. This study provides a new strategy for the effective treatment of antibiotic wastewater and hopes to be applied to the treatment of actual antibiotic wastewater in the future. [ABSTRACT FROM AUTHOR]

The structure and function of human leucocyte antigen (HLA-A) is well known and is an extremely variable protein. From the public HLA-A database, we chose 26 high frequency HLA-A alleles (45% of sequenced alleles). Using five arbitrary references from these alleles, we analyzed synonymous mutations at the third codon position (sSNP3) and non-synonymous mutations (NSM). Both mutation types showed non-random locations of 29 sSNP3 codons and 71 NSM codons in the five reference lists. Most sSNP3 codons show identical mutation types with many mutations resulting from cytosine deamination. We proposed 23 ancestral parents of sSNP3 in five reference sequences using conserved parents in five unidirectional codons and 18 majority parents in reciprocal codons. These 23 proposed ancestral parents show exclusive codon usage of G3 or C3 parents located on both DNA strands that mutate to A3 or T3 variants mostly (76%) by cytosine deamination The sSNP3 and NSM show clear separation of the two variant types with most sSNP3 located in conserved areas in exons 2, 3 and 4, compared to most NSM appearing in two Variable Areas with no sSNP3 in the latter parts of exons 2 (α1) and 3 (α2). The Variable Areas contain NSM (polymorphic) residues at the center of the groove that bind the foreign peptide. We find distinctly different mutation patterns in NSM codons from those of sSNP3. Namely, G-C to A-T mutation frequency was much smaller, suggesting that evolutional pressures of deamination and other mechanisms applied to the two areas are significantly different. [ABSTRACT FROM AUTHOR]

Endonuclease V (EndoV), which is widespread in bacteria, eukarya and Archaea, can cleave hypoxanthine (Hx)-containing DNA or RNA strand, and play an essential role in Hx repair. However, our understanding on archaeal EndoV's function remains incomplete. The model archaeon Sulfolobus islandicus REY15A encodes a putative EndoV protein (Sis-EndoV). Herein, we probed the biochemical characteristics of Sis-EndoV and dissected the roles of its seven conserved residues. Our biochemical data demonstrate that Sis-EndoV displays maximum cleavage efficiency at above 60 °C and at pH 7.0–9.0, and the enzyme activity is dependent on a divalent metal ion, among which Mg2+ is optimal. Importantly, we first measured the activation energy for cleaving Hx-containing ssDNA by Sis-EndoV to be 9.6 ± 0.8 kcal/mol by kinetic analyses, suggesting that chemical catalysis might be a rate-limiting step for catalysis. Mutational analyses show that residue D38 in Sis-EndoV is essential for catalysis, but has no role in DNA binding. Furthermore, we first revealed that residues Y41 and D189 in Sis-EndoV are involved in both DNA cleavage and DNA binding, but residues F77, H103, K156 and F161 are only responsible for DNA binding. [ABSTRACT FROM AUTHOR]

The reaction of adamantane-2-carboxylc acid with excess chlorine in the presence of aluminum chloride on heating gave 5,7-dichloroadamantane-2-carboxylic acid which was subjected to consecutive Curtius reaction, deamination, and oxidation to obtain 5,7-dichloroadamantan-2-one. The latter is a key substrate for the synthesis of new compounds and materials with a combination of practically important properties, in particular for the preparation of biologically active compounds and systems for chemiluminescence diagnostics. [ABSTRACT FROM AUTHOR]

Controlled drug release systems have the characteristics of eliminating or reducing side effects and producing a therapeutic concentration of the drug that is stable in the body. The synthesis of hydrogels from natural polymers allows innovation in new materials that promote more effective, selective and safe therapies, in comparison with hydrogel systems based on synthetic polymers where their main limitation may be their biocompatibility and degradation. For this reason, in this work the synthesis of hydrogels of chitosan crosslinked with glutamic acid is proposed as the basis of new trends in smart materials for their potential use in the controlled release of drugs, the hydrogels were prepared from an amidation reaction between the amino groups of chitosan and the carboxyl groups of L-glutamic acid, using N-(3-Dimethylaminopropyl)-N′-ethylcarbodiimide hydrochloride (EDC) as activator of the carboxyl groups. The hydrogels obtained were characterized by SEM, FTIR, TGA techniques, swelling kinetics and antimicrobial activity. They exhibited excellent swelling capacity and good performance when exposed to different pH and temperature conditions. The bacterial inhibition percentages demonstrated the antimicrobial activity of chitosan hydrogels and the results obtained potentially favored their use as reservoirs for controlled drug release. [ABSTRACT FROM AUTHOR]

Immunoassays employed to measure C-peptide in rat serum neither have high sensitivity nor good range. Hence, the aim of this work was to develop a sensitive and specific user friendly immunoradiometric assay (IRMA) utilizing in-house magnetizable cellulose particles for quantification of C-peptide in rat serum. For development of IRMA, detector antibody (M1*) was prepared by chloramine-T method using 125I and capture antibody (SM2) was prepared by carbonyldiimidazole (CDI) activation method. The matched pair M1*-SM2 yielded an assay with adequate sensitivity (0.24 ng/ml) and range (0–20 ng/ml). C-peptide concentrations in rat serum samples (n = 30) analyzed using the developed assay ranged between 0.3 and 0.54 ng/ml. The reported C-peptide range can be used as a reference in impending diabetic research carried out using rat models. [ABSTRACT FROM AUTHOR]

Adenosine deaminase acting on RNA (ADAR) enzyme–mediated A-to-I RNA editing is widely distributed in the transcriptome. It plays an important role in autoimmune surveillance, tumorigenesis, and development. Recently, several site-directed RNA editing (SDRE) systems have been developed to target disease causative point mutations by flexibly exploiting the catalytic adenosine deamination properties of ADARs. This is based on the fact that A-to-I RNA editing is essentially an adenosine-guanine transition. In contrast to genome editing, RNA editing is tunable and transient, and there are still some shortcomings that need to be addressed. Here, we outline several SDRE systems that rely on the catalytic deamination activity of endogenous or exogenous ADARs, attempting to illustrate their strategies and discuss numerous shortcomings that need to be overcome in the future. [ABSTRACT FROM AUTHOR]

Inactivating mutations of MBD4 have been reported in subsets of various tumors. A deficiency of this DNA glycosylase, recognizing specifically T:G mismatch resulting from the deamination of methyl-cytosine, results in a hypermutated phenotype due to the accumulation of CpG>TpG transitions. Here, we hypothesize that the difference in DNA metabolism consecutive to MBD4 deficiency may result in specific cytotoxicities in MBD4-deficient tumor cells in a synthetic lethality fashion. After a large-scale drug repurposing screen, we show in two isogenic MBD4 knock-out cell models that the inactivation of MBD4 sensitizes cancer cells to cytidine analogs. We further confirm the exquisite activity of gemcitabine in an MBD4-deficient co-clinical model as (i) it completely prevented the development of an MBD4-deficient uveal melanoma patient-derived xenograft and (ii) treatment in the corresponding patient resulted in an exceptional tumor response. These data suggest that patients harboring MBD4-deficient tumors may be treated efficiently by cytidine analogs. [ABSTRACT FROM AUTHOR]

The removal of protein charge variants due to complex chemical and enzymatic modifications like glycosylation, fragmentation and deamidation presents a significant challenge in the purification of monoclonal antibodies (mAb) and complicates downstream processing. These protein modifications occur either in vivo or during fermentation and downstream processing. The presence of charge variants can lead to diminished biological activity, differences in pharmacokinetics, pharmacodynamics, stability and efficacy. Therefore, these different product variants should be appropriately controlled for the consistency of product quality and to ensure patient safety. This investigation focuses on the development of a chromatography step for the removal of the charge variants from a recombinant single-chain variable antibody fragment (scFv−Fc−Ab). Poly(ethyleneimine)-grafted cation-exchange resins (Poly CSX and Poly ABX) were evaluated and compared to traditional macroporous cation-exchange and tentacle cation-exchange resins. Linear salt gradient experiments were conducted to study the separation efficiency of scFv–Fc–Ab variants using different resins. A classical thermodynamic model was used to develop a mechanistic understanding of the differences in charge variant retention behaviour of different resins. High selectivity in separation of scFv−Fc−Ab charge variants is obtained in the Poly CSX resin. [ABSTRACT FROM AUTHOR]

Herein, the potential of alkaline hydrothermal environments for the synthesis of possible ancestral pre-RNA nucleobases using cyanide as a primary source of carbon and nitrogen is described. Water cyanide polymerizations were assisted by microwave radiation to obtain high temperature and a relatively high pressure (MWR, 180 °C, 15 bar) and were also carried out using a conventional thermal system (CTS, 80 °C, 1 bar) to simulate subaerial and aerial hydrothermal conditions, respectively, on the early Earth. For these syntheses, the initial concentration of cyanide and the diffusion effects were studied. In addition, it is well known that hydrolysis conditions are directly related to the amount and diversity of organic molecules released from cyanide polymers. Thus, as a first step, we studied the effect of several hydrolysis procedures, generally used in prebiotic chemistry, on some of the potential pre-RNA nucleobases of interest, together with some of their isomers and/or deamination products, also presumably formed in these complex reactions. The results show that the alkaline hydrothermal scenarios with a relatively constant pH are good geological scenarios for the generation of noncanonical nucleobases using cyanide as a prebiotic precursor. [ABSTRACT FROM AUTHOR]

Purpose: Physiological parameters such as adiposity and age are likely to influence protein digestion and utilization. The aim of this study was to evaluate the combined effects of age and adiposity on casein protein and amino acid true digestibility and its postprandial utilization in rats. Methods: Four groups were included (n = 7/8): 2 months/normal adiposity, 2 months/high adiposity, 11 months/normal adiposity and 11 months/high adiposity. Rats were given a calibrated meal containing 15N-labeled casein (Ingredia, Arras, France) and were euthanized 6 h later. Digestive contents were collected to assess protein and amino acid digestibilities. 15N enrichments were measured in plasma and urine to determine total body deamination. Fractional protein synthesis rate (FSR) was determined in different organs using a flooding dose of 13C valine. Results: Nitrogen and amino acid true digestibility of casein was around 95–96% depending on the group and was increased by 1% in high adiposity rats (P = 0.04). Higher adiposity levels counteracted the increase in total body deamination (P = 0.03) that was associated with older age. Significant effects of age (P = 0.006) and adiposity (P = 0.002) were observed in the muscle FSR, with age decreasing it and adiposity increasing it. Conclusion: This study revealed that a higher level of adiposity resulted in a slight increase in protein and individual amino acid true digestibility values and seemed to compensate for the metabolic postprandial protein alterations observed at older age. [ABSTRACT FROM AUTHOR]

Red mud is a kind of strong alkaline hazardous slag discharged from aluminum metallurgy industry. In this study, the water immersion with high temperature and high pressure was developed for the selective dealkalization from red mud by adding Mg-based additives. The removal efficiency of alkali could reach 92% by using 12% MgCl2 with 9 mL/g at 250 °C for 60 min. The MgCl2 was the most effective leaching reagent to promote the decomposion of cancrinite lattice. The new minerals bearing Mg, i.e., chlorite (Mg5Al2Si3O10(OH)8) and pyrope (Mg3Al2Si3O12) could be formed, which was in favor of transforming the structural alkali into the free alkali by the analysis and validation of XRD and SEM-EDS. The dealkalization process was mainly controlled by chemical reactions according to the analysis of unreacted shrinking core model (USCM) of leaching kinetics. The leaching kinetics equation of 1 − (1 − x)1/3 = 32.2 × exp[4582.6 / T] × t was built and the apparent activation energy of 38.1 kJ/mol was obtained. This method may provide a new and cleaner way for the efficient dealkalization of red mud and a basis for the utilization of leaching residue as the soil amendment. [ABSTRACT FROM AUTHOR]

A convenient procedure to access 1-[(1,1′-biphenyl)-4-yl]naphthalene by the Stevens rearrangement of the aminium salts bearing simultaneously 3-phenylprop-2-enyl and [3-(α-naphthyl)prop-2-ynyl] moieties was developed. During vacuum distillation, the synthesized compounds underwent the domino reaction to afford 1-[(1,1′-biphenyl)-4-yl]naphthalene. On the first step of this reaction, β-elimination of secondary amines gave the conjugated dienyne; on the second step, the electrocyclic reaction of dienyne resulted in cyclic allene intermediate; on the third step, allene intermediate rapidly transformed to 1-[(1,1′-biphenyl)-4-yl]naphthalene via either 1,3- or 1,5-hydrogen shift. [ABSTRACT FROM AUTHOR]

Twinning-induced plasticity (TWIP) steel offers high strength and ductility. However, in this study, deformation-induced detwinning was studied to prove that not all twins significantly benefit the mechanical properties. The quasi in situ observation results indicated that submicron-sized twins were unstable during Charpy impact loading. In contrast to the TWIP concept, analysis of the geometrically necessary dislocation evolution associated with detwinning revealed that unstable twins have negligible influence on the pile-ups of dislocations, offering a limited strengthening effect. [ABSTRACT FROM AUTHOR]

An extensive proteomic analysis was performed on a set of 12 bones of human victims of the eruption that in AD 79 rapidly buried Pompeii and Herculaneum, allowing the detection of molecular signatures imprinted in the surviving protein components. Bone collagen survived the heat of the eruption, bearing a piece of individual biological history encoded in chemical modifications. Here we show that the human bone proteomes from Pompeii are more degraded than those from the inhabitants of Herculaneum, despite the latter were exposed to temperatures much higher than those experienced in Pompeii. The analysis of the specimens from Pompeii shows lower content of non-collagenous proteins, higher deamidation level and higher extent of collagen modification. In Pompeii, the slow decomposition of victims' soft tissues in the natural dry–wet hydrogeological soil cycles damaged their bone proteome more than what was experienced at Herculaneum by the rapid vanishing of body tissues from intense heat, under the environmental condition of a permanent waterlogged burial context. Results herein presented are the first proteomic analyses of bones exposed to eruptive conditions, but also delivered encouraging results for potential biomarkers that might also impact future development of forensic bone proteomics. [ABSTRACT FROM AUTHOR]

Casein is a commonly used protein in the food industry, with its related products such as beverages and desserts. However, the further application of casein is limited by its solubility and stability. This study aimed to improve the functional of casein through protein-glutaminase (PG) deamination. The deamination of casein using PG was optimized through central composite design experiments, and its impact on the structure, solubility, and stability of casein was investigated. The results demonstrate that the optimal conditions for PG deamidation were determined at pH 6.0, E/S 15 U/g, and a temperature of 45 °C. The deamidation process alters the secondary structure of casein, resulting in a decrease in α-helix structure and an increase in β-sheet structure. The modification of casein improved emulsifying activity at pH 8.0 and 10.0, respectively, while significantly enhancing the solubility from 5.0 to 6.0. Furthermore, the deamidation of casein caused an increase in zeta potential and a decrease in particle size, resulting in improved stability of the protein solution due to reduced particle aggregation. The 3% deamidated casein-based beverage with carrageenan exhibited reduced precipitation rates compared to the control after sterilization at 121 °C for 15 min. In summary, PG deamidation offers a promising method for the modification and enhancement of the functional properties, including solubility, stability, and emulsifying activity of casein, thereby expanding its use of casein in the food industry. [ABSTRACT FROM AUTHOR]

A liquid chromatography-tandem mass spectrometry method is presented for the quantitative determination of the in vivo deamidation of the biopharmaceutical proteins trastuzumab and pertuzumab at an asparagine in their complementarity determining regions (CDRs). For each analyte, two surrogate peptides are quantified after tryptic digestion of the entire plasma protein content: one from a stable part of the molecule, representing the total concentration, and one containing the deamidation-sensitive asparagine, corresponding to the remaining non-deamidated concentration. Using a plasma volume of 10 µL and a 2-h digestion at pH 7, concentrations between 2 and 1000 µg/mL can be determined for the various protein forms with values for bias and CV below 15% and without unacceptable in vitro deamidation taking place. A considerable difference between the total and non-deamidated concentrations, and thus a substantial degree of deamidation, was observed in plasma for both trastuzumab and pertuzumab. After a 56-day forced deamidation test 40% of trastuzumab and 68% of pertuzumab was deamidated, while trastuzumab and pertuzumab showed up to 47% and 35% of deamidation, respectively, in samples collected from breast cancer patients during treatment with a combination of both drugs. A good correlation between the non-deamidated concentration results and those of a receptor binding assay indicate a loss of receptor binding for both trastuzumab and pertuzumab along with the deamidation in their CDRs. Deamidated trastuzumab also lost its capability to inhibit the growth of breast cancer cells in a cell-based viability assay, suggesting a relation between the degree of deamidation and pharmacological activity. [ABSTRACT FROM AUTHOR]

This study introduces a novel geotechnical composite material comprising two types of fill material sourced from the paper industry—deinking paper sludge ash (DPSA) and deinking paper sludge (DPS). Five composites with different DPSA and DPS contents were investigated. Two composites were selected for further analyses. The technology and procedure for composite installation were implemented in field tests. The composites with 80% and 70% DPSA exhibited the elasticity required to withstand minor landslide slip deformations, in addition to achieving sufficiently high values of uniaxial compressive strength. The composites had a low maximum dry density value, which led to fewer settlements in the entire support structure. The enhanced shear characteristics can enable the construction of a thinner retaining wall. The delay between preparation and installation of the composites was further investigated. The field tests confirmed that the composites with 80% and 70% DPSA can be installed on the construction site 4 h and even 24 h after mixing. In 2018, a retaining wall structure with 70% DPSA and 30% DPS was successfully implemented near a railway line using conventional technology as followed-up research to the herein presented study. Results have been derived from work performed in the scope of the H2020 Paperchain project in which novel circular economy models centered on the valorization of the waste streams generated by the pulp and paper industry as secondary raw material for several resource-intensive sectors, including the construction sector, have been developed. Environmental benefits are savings in natural raw materials, reduction of landfill disposal as well as CO2 emission reduction. [ABSTRACT FROM AUTHOR]

Proteins are the main N compounds and are important sources of both C and N for plants and microbes. Triple-labeled dissolved organic N obtained from white clover shoots was separated into five different molecular weight (Mw) size fractions (> 1 kDa). In this study, we investigated the mineralization of and the presence of C and N remaining in soil solution over 14 days across different soil pH values. The evolved CO2 decreased by increasing Mw, suggesting an apparent bottleneck in the decomposition of organic N above Mw 30 kDa. The initial parallel loss of 13C and 15 N from soil was followed by an increase in dissolved 15 N describing a two-phase process of organic N turnover. The first-phase concerns the removal of organic N whereas the second-phase concerns the release of inorganic N. Microbial N and C use efficiency was increased with increasing Mw size suggesting the importance of organic N quality in predicting the impact on soil C and N cycling. [ABSTRACT FROM AUTHOR]

Celiac disease (CeD) is a T-cell-dependent enteropathy with autoimmune features where tissue transglutaminase (TG2)-mediated posttranslational modification of gliadin peptides has a decisive role in the pathomechanism. The humoral immune response is reported to target mainly TG2-deamidated γ-gliadin peptides. However, α-gliadin peptides, like p57-68, playing a crucial role in the T-cell response, and p31-43, a major trigger of innate responses, also contain B-cell gliadin epitopes and γ-gliadin like motifs. We aimed to identify if there are anti-gliadin-specific antibodies in CeD patients targeting the p31-43 and p57-68 peptides and to examine whether deamidation of these peptides could increase their antigenicity. We explored TG2-mediated deamidation of the p31-43 and p57-68 peptides, and investigated serum antibody reactivity toward the native and deamidated α and γ-gliadin peptides in children with confirmed CeD and in prospectively followed infants at increased risk for developing CeD. We affinity-purified antibody populations utilizing different single peptide gliadin antigens and tested their binding preferences for cross-reactivity in real-time interaction assays based on bio-layer interferometry. Our results demonstrate that there is serum reactivity toward p31-43 and p57-68 peptides, which is due to cross-reactive γ-gliadin specific antibodies. These γ-gliadin specific antibodies represent the first appearing antibody population in infancy and they dominate the serum reactivity of CeD patients even later on and without preference for deamidation. However, for the homologous epitope sequences in α-gliadins shorter than the core QPEQPFP heptapeptide, deamidation facilitates antibody recognition. These findings reveal the presence of cross-reactive antibodies in CeD patients recognizing the disease-relevant α-gliadins. [ABSTRACT FROM AUTHOR]

Genomes of hyperthermophiles are facing a severe challenge due to increased deamination rates of cytosine induced by high temperature, which could be counteracted by base excision repair mediated by uracil DNA glycosylase (UDG) or other repair pathways. Our previous work has shown that the two UDGs (Tba UDG247 and Tba UDG194) encoded by the genome of the hyperthermophilic euryarchaeon Thermococcus barophilus Ch5 can remove uracil from DNA at high temperature. Herein, we provide evidence that Tba UDG247 is a novel bifunctional glycosylase which can excise uracil from DNA and further cleave the phosphodiester bo nd of the generated apurinic/apyrimidinic (AP) site, which has never been described to date. In addition to cleaving uracil-containing DNA, Tba UDG247 can also cleave AP-containing ssDNA although at lower efficiency, thereby suggesting that the enzyme might be involved in repair of AP site in DNA. Kinetic analyses showed that Tba UDG247 displays a faster rate for uracil excision than for AP cleavage, thus suggesting that cleaving AP site by the enzyme is a rate-limiting step for its bifunctionality. Phylogenetic analysis showed that Tba UDG247 is clustered on a separate branch distant from all the reported UDGs. Overall, we designated Tba UDG247 as the prototype of a novel family of bifunctional UDGs. Key points: We first reported a novel DNA glycosylase with bifunctionality. Tba UDG247 possesses an AP lyase activity. [ABSTRACT FROM AUTHOR]

A novel alanine dehydrogenase (AlaDH; EC.1.4.1.1) was isolated from Amycolatopsis sulphurea and the AlaDH gene was cloned into a pET28a(+) plasmid and expressed in E. coli BL21 (DE3). The molecular mass of this enzyme was calculated as 41.09 kDa and the amino acid residues of the pure protein indicated the presence of N terminus polyhistidine tags. Its enzyme kinetic values were Km 2.03 mM, kcat 13.24 (s−1), and kcat/Km 6.53 (s−1 mM−1). AlaDH catalyzes the reversible conversion of l-alanine and pyruvate, which has an important role in the TCA energy cycle. Maximum AlaDH activity occurred at about pH 10.5 and 25 °C for the oxidative deamination of l-alanine. AlaDH retained about 10% of its relative activity at 55 °C and it remained about 90% active at 50 °C. These findings show that the AsAlaDH from A. sulphurea has the ability to produce valuable molecules for various industrial purposes and could represent a new potential biocatalyst for biotechnological applications after further characterization and improvement of its catalytic properties. [ABSTRACT FROM AUTHOR]

Deamination of L-glutamine to glutamic acid with the concomitant release of ammonia by the activity of L-glutaminase (L-glutamine amidohydrolase EC 3.5.1.2) is a unique reaction that also finds potential applications in different sectors ranging from therapeutics to food industry. Owing to its cost-effectiveness, rapidity, and compatibility with downstream processes, microbial production of L-glutaminase is preferred over the production by other sources. Marine microorganisms including bacteria, yeasts, and moulds have manifested remarkable capacity to produce L-glutaminase and, therefore, are considered as prospective candidates for large-scale production of this enzyme. The main focus of this article is to provide an overview of L-glutaminase producing marine microorganisms, to discuss strategies used for the lab- and large-scale production of these enzyme and to review the application of L-glutaminase from marine sources so that the future prospects can be understood. Key points: • L-glutaminase has potential applications in different sectors ranging from therapeutics to food industry • Marine microorganisms are considered as prospective candidates for large-scale production of L-glutaminase • Marine microbial L-glutaminase have great potential in therapeutics and in the food industry [ABSTRACT FROM AUTHOR]

Livestock has a significant contribution to methane emission as a portion of their ingested energy, which is wasted in the form of methane (2–15%), and ammonia (75–95%). Microbial fermentation in ruminants results in the loss of energy in methanogenesis and protein via ammonia nitrogen excretion, causing a decline in feed efficiency and acting as environmental pollutants. Antibiotics were used to reduce these losses in the rumen, but this approach was restricted in animal products. Some plants or their bioactive extracts/metabolites such as organo-sulphur compounds, saponins, essential oils, flavonoids, and tannins exhibited the potential to limit the methanogenesis by altering the rumen microflora. Plant extracts, including clove (Syzygium aromaticum) bud oil and clove extracts, were used as feed additives to manipulate rumen fermentation. Clove oil interacts with bacterial cells and inhibits the growth multiplication of methanogenic and deaminating bacteria. This results in a reduction in ammonia, nitrogen, methane, acetate concentration, and high propionate and butyrate concentrations. Eugenol is one of the bioactive constituents in clove that manipulate rumen fermentation by increasing propionate production, decrease acetate and methane production, and alter the proteolysis pattern, peptidolysis, and amino acid deamination in the rumen. The current review reports on using of clove phytochemicals and extracts in manipulating rumen fermentation to inhibit methanogenesis and energy loss as well as ammonia–nitrogen waste. [ABSTRACT FROM AUTHOR]

Protein-glutaminase (PG) is a promising protein deaminase. It only hydrolyzes the side chain amido groups of protein-bound to generate ammonia and protein-L-glutamic acid and does not catalyze any other undesirable changes in protein structures. Deamidation of proteins via PG can influence the solubility, emulsification, foaming, and gelation properties of proteins, which are important properties for some food proteins. Therefore, there is great potential for the application of PG in the food industry. PG is derived from Chryseobacterium proteolyticum (C. proteolyticum); however, wild strains are difficult to industrialize because of their low levels of enzyme production. In this article, we studied different strategies for PG expression in B. subtilis. Results showed that PG produced from C. proteolyticum could be successfully secreted in B. subtilis WB800N, and actively secreted in B. subtilis 168(BS168) or DB403 containing a pro-peptide (pro-PG). The secreted PG from B. subtilis WB800N was inactive unless digested by exogenous proteases, such as trypsin, alkaline protease, and neutral protease. However, active PG was secreted by the self-processing of BS168 and DB403. The specific activity of purified PG reached 20.9 U/mg. PG showed maximum activity at pH 5.5, 55 °C and more than 80% of PG activity was retained within a range of pH 3.5–6.5. When Cbz-Gln-Gly was used as the substrate, PG activity was 31.1 ± 0.9 μM min−1 mg−1. Mg2+, Ca2+, and Zn2+ stabilized and even activated PG activity. These strategies concerning PG expression in B. subtilis and the enzymatic properties of PG provide efficient alternatives for PG research and contribute to the industrial-scale production of PG. [ABSTRACT FROM AUTHOR]

The origins, prevalence and nature of dairying have been long debated by archaeologists. Within the last decade, new advances in high-resolution mass spectrometry have allowed for the direct detection of milk proteins from archaeological remains, including ceramic residues, dental calculus, and preserved dairy products. Proteins recovered from archaeological remains are susceptible to post-excavation and laboratory contamination, a particular concern for ancient dairying studies as milk proteins such as beta-lactoglobulin (BLG) and caseins are potential laboratory contaminants. Here, we examine how site-specific rates of deamidation (i.e., deamidation occurring in specific positions in the protein chain) can be used to elucidate patterns of peptide degradation, and authenticate ancient milk proteins. First, we characterize site-specific deamidation patterns in modern milk products and experimental samples, confirming that deamidation occurs primarily at low half-time sites. We then compare this to previously published palaeoproteomic data from six studies reporting ancient milk peptides. We confirm that site-specific deamidation rates, on average, are more advanced in BLG recovered from ancient dental calculus and pottery residues. Nevertheless, deamidation rates displayed a high degree of variability, making it challenging to authenticate samples with relatively few milk peptides. We demonstrate that site-specific deamidation is a useful tool for identifying modern contamination but highlight the need for multiple lines of evidence to authenticate ancient protein data. [ABSTRACT FROM AUTHOR]

In this work, an innovative non-destructive monitoring methodology based on the analysis over time of open-air rock art sites is presented. This approach is based on the combination of in situ spectroscopic and chemometric studies to diagnose and monitor the state of conservation of rock art sites. Data acquired over a period of time by non-invasive analytical techniques such as portable Raman spectrometry (RS) and handheld energy-dispersive X-ray fluorescence (HH-EDXRF) spectrometry are compared to detect physicochemical changes that could affect the rock painting integrity. To demonstrate the applicability of the proposed procedure, three analysis campaigns (between 2013 and 2016) were carried out, analyzing Levantine rock pictographs preserved in the rock shelter of Solana de las Covachas VI (Albacete, Spain; see Electronic Supplementary Material (ESM) Fig. S1). The analyzed areas showed different types of active weathering processes such as gypsum and calcium oxalate formation, giving rise to conservation issues such as painting fading, surface loss, microbial colonizations, and formation of crusts. Results evidence that the proposed methodology can be very useful to monitor chemical changes in the surface of the walls where the rock art is located, thus obtaining crucial information for its preservation and management. [ABSTRACT FROM AUTHOR]

Confidentiality and integrity are fundamental requirements when transmitting and storing data. In order to guarantee the confidentiality and integrity of speech signal, we present a novel wateRmarking scheme for Encrypted sPeech AuthenticatIon with Recovery (REPAIR) scheme. In REPAIR, an encryption algorithm is first designed based on a hyper-chaotic method to improve the confidentiality of the original speech by encryption. Subsequently, a watermark generation and embedding algorithm is proposed to generate and embed the check bits and compression bits. Afterwards, a content authentication and tampering recovery algorithm is introduced to locate and recover the tampered speech frames. Meanwhile, a speech decryption algorithm is also presented to decrypt the encrypted speech. Analysis and experimental results demonstrate that REPAIR can detect and locate synchronization attacks and de-synchronization attacks without using the auxiliary synchronous code. Additionally, REPAIR can also recover the tampered content with high quality. [ABSTRACT FROM AUTHOR]

Possible synthetic routes to 4-bromo-1,1′:4′,1″-terphenyl and 4-methyl-1,1′:4′,1″-terphenyl have been studied. Stevens rearrangement of quaternary ammonium salts containing 3-phenylprop-2-en-1-yl and 3-(4-bromo- or 4-methylphenyl)prop-2-yn-1-yl groups gave 1-(4-bromophenyl)-N,N-dimethyl-4-phenylhex-5-en-1-yn-3-amine, 1-(4-bromophenyl)-N,N-diethyl-4-phenylhex-5-en-1-yn-3-amine, 1-(4-bromophenyl)-4-phenyl-N,N-dipropylhex-5-en-1-yn-3-amine, 1-[1-(4-bromophenyl)-4-phenylhex-5-en-1-yn-3-yl]piperidine, 4-[1-(4-bromophenyl)-4-phenylhex-5-en-1-yn-3-yl]morpholine, 1-[1-(4-methylphenyl)-4-phenylhex-5-en-1-yn-3-yl]piperidine, and 4-[1-(4-methylphenyl)-4-phenylhex-5-en-1-yn-3-yl]morpholine. Vacuum distillation of the resulting amines, by analogy with structurally related compounds, was accompanied by deamination with the formation of 4-bromo-1,1′:4′,1″-terphenyl and 4-methyl-1,1′:4′,1″-terphenyl in high yields. This transformation is a domino reaction involving β-elimination of secondary amine to form conjugated dienyne, electrocyclization of the latter to cyclic allene intermediate, and fast 1,3- or 1,5-hydride shift. [ABSTRACT FROM AUTHOR]

Objectives: To screening of bacteria with cyclic amino alcohol deamination activity for enantioselective synthesis of chiral cyclic β-amino alcohols. Results: A new strain named Arthrobacter sp. TYUT010-15 with the (R)-selective deamination activity of cyclic β-amino alcohol has been isolated from nature via a high throughput solid-phase screening method. The reaction conditions of TYUT010-15 were optimized. Using the resting cell of TYUT010-15 as the catalyst, kinetic resolution of trans-2-aminocyclopentanol, trans-2-aminocyclohexanol and cis-1-amino-2-indanol was carried out to afford (1S, 2S)-trans-2-aminocyclopentanol, (1S, 2S)-trans-2-aminocyclohexanol and (1R, 2S)-cis-1-amino-2-indanol in > 99% ee and 49.6–50% conversion. Four aromatic β-amino alcohols and two amines were also resolved, (S)-β-amino alcohols and (R)-amines were obtained in > 99% ee. Preparation experiment was conducted with 200 mM (23.2 g L−1) racemic trans-2-aminocyclohexanol, yielding the desired (1S, 2S)-trans-2-aminocyclohexanol in 40% isolated yield, > 99% ee and 5.8 g L−1 d−1 space time yields. Conclusions: This study provides a high throughput solid-phase method for screening of bacteria with cyclic amino alcohol deamination activity and a first example for practical preparation of chiral cyclic β-amino alcohol by Arthrobacter sp. TYUT010-15. [ABSTRACT FROM AUTHOR]

The bacterial effector MavC catalyzes non-canonical ubiquitination of host E2 enzyme UBE2N without engaging any of the conventional ubiquitination machinery, thereby abolishing UBE2N's function in forming K63-linked ubiquitin (Ub) chains and dampening NF-кB signaling. We now report the structures of MavC in complex with conjugated UBE2N~Ub and an inhibitor protein Lpg2149, as well as the structure of its ortholog, MvcA, bound to Lpg2149. Recognition of UBE2N and Ub depends on several unique features of MavC, which explains the inability of MvcA to catalyze ubiquitination. Unexpectedly, MavC and MvcA also possess deubiquitinase activity against MavC-mediated ubiquitination, highlighting MavC as a unique enzyme possessing deamidation, ubiquitination, and deubiquitination activities. Further, Lpg2149 directly binds and inhibits both MavC and MvcA by disrupting the interactions between enzymes and Ub. These results provide detailed insights into catalysis and regulation of MavC-type enzymes and the molecular mechanisms of this non-canonical ubiquitination machinery. The bacterial effector MavC can ubiquitinate the host E2 enzyme UBE2N to dampen the host immune response. Here, the authors provide mechanistic insight into this non-canonical ubiquitination machinery and reveal the structural basis for the functional differences between MavC and its close homolog MvcA. [ABSTRACT FROM AUTHOR]

Multi-nucleotide variants (MNVs), defined as two or more nearby variants existing on the same haplotype in an individual, are a clinically and biologically important class of genetic variation. However, existing tools typically do not accurately classify MNVs, and understanding of their mutational origins remains limited. Here, we systematically survey MNVs in 125,748 whole exomes and 15,708 whole genomes from the Genome Aggregation Database (gnomAD). We identify 1,792,248 MNVs across the genome with constituent variants falling within 2 bp distance of one another, including 18,756 variants with a novel combined effect on protein sequence. Finally, we estimate the relative impact of known mutational mechanisms - CpG deamination, replication error by polymerase zeta, and polymerase slippage at repeat junctions - on the generation of MNVs. Our results demonstrate the value of haplotype-aware variant annotation, and refine our understanding of genome-wide mutational mechanisms of MNVs. Multi-nucleotide variants (MNV) are genetic variants in close proximity of each other on the same haplotype whose functional impact is difficult to predict if they reside in the same codon. Here, Wang et al. use the gnomAD dataset to assemble a catalogue of MNVs and estimate their global mutation rate. [ABSTRACT FROM AUTHOR]

Myocardial ischemia and infarction represent a major health burden worldwide, but their immediate diagnosis can reduce mortality and healthcare costs. Pyroglutamate helix B surface peptide (pHBSP) derived from erythropoietin have shown tissue-protective effects in the ischemic situation by binding to erythropoietin receptor–Beta common receptors)EPOR–βcR(. This research aimed to synthesize and biologically evaluate p-NH2-Bn-DTPA-(Lys-Dabcyl6,Phe7)-pHBSP for cardiac ischemia imaging. Radiolabeling yielded more than 97%, and radiolabeled peptide showed significant binding affinity to H9c2 hypoxic cells (p < 0.001). A considerable accumulation of 99mTc-p-NH2-Bn-DTPA-(Lys-Dabcyl6,Phe7)-pHBSP was detected in the ischemic region by biodistribution study and SPECT/CT scintigraphy (3.84 ID/g% at 30 min). [ABSTRACT FROM AUTHOR]

Cytosine base editors (CBEs) enable efficient, programmable reversion of T•A to C•G point mutations in the human genome. Recently, cytosine base editors with rAPOBEC1 were reported to induce unguided cytosine deamination in genomic DNA and cellular RNA. Here we report eight next-generation CBEs (BE4 with either RrA3F [wt, F130L], AmAPOBEC1, SsAPOBEC3B [wt, R54Q], or PpAPOBEC1 [wt, H122A, R33A]) that display comparable DNA on-target editing frequencies, whilst eliciting a 12- to 69-fold reduction in C-to-U edits in the transcriptome, and up to a 45-fold overall reduction in unguided off-target DNA deamination relative to BE4 containing rAPOBEC1. Further, no enrichment of genome-wide C•G to T•A edits are observed in mammalian cells following transfection of mRNA encoding five of these next-generation editors. Taken together, these next-generation CBEs represent a collection of base editing tools for applications in which minimized off-target and high on-target activity are required. Cytosine base editors have been reported to induce off-target mutations in DNA and RNA. Here the authors identify next-generation CBEs with reduced guide-independent off-target editing profiles and retain high on-target editing activity. [ABSTRACT FROM AUTHOR]

Insect venom is a highly complex mixture of bioactive compounds, containing proteins, peptides, and small molecules. Environmental factors can alter the venom composition and lead to intraspecific variation in its bioactivity properties. The investigation of discriminating compounds caused by variation impacts can be a key to manage sampling and explore the bioactive compounds. The present study reports the development of a peptidomic methodology based on UHPLC–ESI-QTOF–HRMS analysis followed by a nontargeted multivariate analysis to reveal the profile variance of Vespa velutina venom collected in different conditions. The reliability of the approach was enhanced by optimizing certain XCMS data processing parameters and determining the sample peak threshold to eliminate the interfering features. This approach demonstrated a good repeatability and a criterion coefficient of variation (CV) > 30% was set for deleting nonrepeatable features from the matrix. The methodology was then applied to investigate the impact of collection period variation. PCA and PLS-DA models were used and validated by cross-validation and permutation tests. A slight discrimination was found between winter and summer hornet venom in two successive years with 10 common discriminating compounds. [ABSTRACT FROM AUTHOR]

Resistance spot welding (RSW) is one of the common assembling process of thin metals. Due to the inaccessibility of nugget in inspection process, usually destructive tests are used to assess weld quality which is time consuming and costly. Finding a practical solution for monitoring of RSW would reduce necessity of these tests for quality control. In this study, a new designed algorithm is used for processing of a video recorded by a high speed camera from resistance spot welding process, to determine the displacement of the electrode (DE), which can be easily applied to any similar process. It was found that the diagram of DE can provide appropriate information about the ongoing events during the resistance spot welding process and gives a suitable tool for monitoring and controlling RSW. The effect of environmental conditions on the DE diagram was also investigated. Impact of expanded heat, melting and expulsion on displacement diagram during the process was discussed. The results showed that current and time have similar trend in DE, higher pressure will result in diagram's compaction. It was also concluded that shunt and contamination have considerable effects on displacement diagram and strengths of weld. Using holders as external constraint can improve weld strength for about 12%. An artificial neural network (ANN)-based program was developed to introduce a relation between displacement diagram and weld quality. In most cases, the predicted values are closed to the experiments. 36 different input modes for welding were investigated in this regard. It is shown that by applying the developed code on DE graph the weld quality can be predicted without need to any destructive test. [ABSTRACT FROM AUTHOR]

The study of the equilibrium of reactions catalyzed by thermostable enzymes is in demand for the development of biotechnological enzyme processes. The results of the analysis of equilibrium of transamination reaction catalyzed by thermostable transaminase from the archaeon Thermoproteus uzoniensis are presented below. A comparison of the conversion of substrates was performed for reactions with L-leucine and pyruvate and L-leucine and 2-oxobutyrate at 65°C. The establishment of the equilibrium was controlled by a decrease in the concentration of 2-oxobutyrate or pyruvate and by the accumulation of the keto analog of L-leucine. It was shown that the degree of conversion of L-leucine in the reaction with specific 2-oxobutyrate is higher than in the reaction with nonspecific pyruvate. [ABSTRACT FROM AUTHOR]

Deamidation is a promising tool to improve solubility and other functional properties of food proteins. One possibility of protein deamidation is the use of a protein glutaminase (PG; EC 3.5.1.44), an enzyme that catalyzes the deamidation of internal glutamine residues in proteins to glutamic acid residues. The PG from Chryseobacterium proteolyticum is the only one described in literature to date and is commercially available (Amano Enzyme Inc., Japan; PGA). Based on a similarity search, we discovered a predicted, uncharacterized protein from Bacteroides helcogenes and this protein was verified as a PG. After recombinant production and purification, the novel PG (BH-PG) was biochemically characterized and compared with PGA. Some advantageous characteristics for potential application of BH-PG compared with PGA were the higher temperature stability (residual activity after 24 h of incubation at 50 °C was 87% for BH-PG and 2% for PGA), an optimum pH value at acidic conditions (pH 5.5) and less product inhibition by ammonia that is released during the deamidation of proteins (residual activity after adding 40 mM ammonia was 77% for BH-PG and 27% for PGA). Finally, the applicability of BH-PG and PGA was compared by gluten deamidation experiments. Consequently, the final solubility of the nearly insoluble food protein gluten was 94% after BH-PG treatment, whereas the solubility was around 66% when using PGA. [ABSTRACT FROM AUTHOR]