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This study investigated an ultrasound (US) treatment strategy in plasma-activated water (PAW) (UP treatment) to inactivate indigenous aerobic bacteria, Escherichia coli O157:H7, and Listeria monocytogenes in fresh-cut celery. Both plasma discharge and US treatment times contributed to the inactivation of indigenous bacteria in celery. The predicted optimal UP treatment conditions included a discharge time of 61.5 min and treatment time of 338 s, resulting in the inactivation of indigenous bacteria, E. coli O157:H7, and L. monocytogenes by 2.7, 1.7, and 3.2 log CFU/g, respectively. With an increase in plasma discharge time or US treatment time, the oxidation-reduction potential and electrical conductivity values of PAW increased, while the pH decreased. UP treatment effectively inactivated bacteria non-thermally, without altering the color of celery. Furthermore, UP treatment led to an increase in cell lipid peroxidation, reactive oxygen species production, and the number of non-viable E. coli O157:H7 and L. monocytogenes cells with membrane damage. This study highlights the potential of UP treatment for bacterial decontamination of fresh-cut celery., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

The effects of ultrasound (US)-assisted plasma-activated water (PAW) washing (UP) on the growth of indigenous bacteria, quality properties, and microbiome of fresh-cut Apium graveolens (celery) were investigated. Among the tested treatments (UP, NaClO solution, US alone, and PAW alone), UP was the most effective in decontaminating fresh-cut celery and inhibiting the growth of natural bacteria in the celery during storage at 4 and 10 °C. No significant differences were observed in the firmness, color, or sensory properties between untreated and UP-treated fresh-cut celery during storage. The proportion of Proteobacteria and Actinobacteria on UP-treated fresh-cut celery decreased after storage at 4 °C for 3 days, confirming the influence of UP treatment on the celery microbiome. The UP treatment induced alterations in the microbial composition of celery. These results demonstrate the potential utility of UP treatment as a novel microbial decontamination process for the preparation of fresh-cut celery products., Competing Interests: Conflict of interestThe authors declare no conflict of interest., (© The Korean Society of Food Science and Technology 2024. Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.)

Intracellular calcium signaling is essential for all kingdoms of life. An important part of this process is the sarco-endoplasmic reticulum Ca 2+ -ATPase (SERCA), which maintains the low cytosolic calcium levels required for intracellular calcium homeostasis. In higher organisms, SERCA is regulated by a series of tissue-specific transmembrane subunits such as phospholamban in cardiac muscles and sarcolipin in skeletal muscles. These regulatory axes are so important for muscle contractility that SERCA, phospholamban, and sarcolipin are practically invariant across mammalian species. With the recent discovery of the arthropod sarcolambans, the family of calcium pump regulatory subunits appears to span more than 550 million years of evolutionary divergence from arthropods to humans. This evolutionary divergence is reflected in the peptide sequences, which vary enormously from one another and only vaguely resemble phospholamban and sarcolipin. The discovery of the sarcolambans allowed us to address two questions. How much sequence variation is tolerated in the regulation of mammalian SERCA activity by the transmembrane peptides? Do divergent peptide sequences mimic phospholamban or sarcolipin in their regulatory activities despite limited sequence similarity? We expressed and purified recombinant sarcolamban peptides from three different arthropods. The peptides were coreconstituted into proteoliposomes with mammalian SERCA1a and the effect of each peptide on the apparent calcium affinity and maximal activity of SERCA was measured. All three peptides were superinhibitors of SERCA, exhibiting either phospholamban-like or sarcolipin-like characteristics. Molecular modeling, protein-protein docking, and molecular dynamics simulations revealed novel features of the divergent peptides and their SERCA regulatory properties.

The sarco-endoplasmic reticulum calcium ATPase (SERCA) is responsible for maintaining calcium homeostasis in all eukaryotic cells by actively transporting calcium from the cytosol into the sarco-endoplasmic reticulum (SR/ER) lumen. Calcium is an important signaling ion, and the activity of SERCA is critical for a variety of cellular processes such as muscle contraction, neuronal activity, and energy metabolism. SERCA is regulated by several small transmembrane peptide subunits that are collectively known as the "regulins". Phospholamban (PLN) and sarcolipin (SLN) are the original and most extensively studied members of the regulin family. PLN and SLN inhibit the calcium transport properties of SERCA and they are required for the proper functioning of cardiac and skeletal muscles, respectively. Myoregulin (MLN), dwarf open reading frame (DWORF), endoregulin (ELN), and another-regulin (ALN) are newly discovered tissue-specific regulators of SERCA. Herein, we compare the functional properties of the regulin family of SERCA transmembrane peptide subunits and consider their regulatory mechanisms in the context of the physiological and pathophysiological roles of these peptides. We present new functional data for human MLN, ELN, and ALN, demonstrating that they are inhibitors of SERCA with distinct functional consequences. Molecular modeling and molecular dynamics simulations of SERCA in complex with the transmembrane domains of MLN and ALN provide insights into how differential binding to the so-called inhibitory groove of SERCA-formed by transmembrane helices M2, M6, and M9-can result in distinct functional outcomes.

The sarcoplasmic reticulum Ca 2+ -ATPase SERCA promotes muscle relaxation by pumping calcium ions from the cytoplasm into the sarcoplasmic reticulum. SERCA activity is regulated by a variety of small transmembrane peptides, most notably by phospholamban in cardiac muscle and sarcolipin in skeletal muscle. However, how phospholamban and sarcolipin regulate SERCA is not fully understood. In the present study, we evaluated the effects of phospholamban and sarcolipin on calcium translocation and ATP hydrolysis by SERCA under conditions that mimic environments in sarcoplasmic reticulum membranes. For pre-steady-state current measurements, proteoliposomes containing SERCA and phospholamban or sarcolipin were adsorbed to a solid-supported membrane and activated by substrate concentration jumps. We observed that phospholamban altered ATP-dependent calcium translocation by SERCA within the first transport cycle, whereas sarcolipin did not. Using pre-steady-state charge (calcium) translocation and steady-state ATPase activity under substrate conditions (various calcium and/or ATP concentrations) promoting particular conformational states of SERCA, we found that the effect of phospholamban on SERCA depends on substrate preincubation conditions. Our results also indicated that phospholamban can establish an inhibitory interaction with multiple SERCA conformational states with distinct effects on SERCA's kinetic properties. Moreover, we noted multiple modes of interaction between SERCA and phospholamban and observed that once a particular mode of association is engaged it persists throughout the SERCA transport cycle and multiple turnover events. These observations are consistent with conformational memory in the interaction between SERCA and phospholamban, thus providing insights into the physiological role of phospholamban and its regulatory effect on SERCA transport activity., (© 2017 by The American Society for Biochemistry and Molecular Biology, Inc.)

Aciniform silk protein (AcSp1) is the primary component of wrapping silk, the toughest of the spider silks because of a combination of high tensile strength and extensibility. Argiope trifasciata AcSp1 contains a core repetitive domain with at least 14 homogeneous 200-amino acid units ("W" units). Upon fibrillogenesis, AcSp1 converts from an α-helix-rich soluble state to a mixed α-helical/β-sheet conformation. Solution-state nuclear magnetic resonance (NMR) spectroscopy allowed demonstration of variable local stability within the W unit, but comprehensive characterization was confounded by spectral overlap, which was exacerbated by decreased chemical shift dispersion upon denaturation. Here, (19)F NMR spectroscopy, in the context of a single W unit (W1), is applied to track changes in structure and dynamics. Four strategic positions in the W unit were mutated to tryptophan and biosynthetically labeled with 5-fluorotryptophan (5F-Trp). Simulated annealing-based structure calculations implied that these substitutions should be tolerated, while circular dichroism (CD) spectroscopy and (1)H-(15)N chemical shift displacements indicated minimal structural perturbation in W1 mutants. Fiber formation by W2 concatemers containing 5F-Trp substitutions in both W units demonstrated retention of functionality, a somewhat surprising finding in light of sequence conservation between species. Each 5F-Trp-labeled W1 exhibited a unique (19)F chemical shift, line width, longitudinal relaxation time constant (T1), and solvent isotope shift. Perturbation to (19)F chemical shift and nuclear spin relaxation parameters reflected changes in the conformation and dynamics at each 5F-Trp site upon addition of urea and dodecylphosphocholine (DPC). (19)F NMR spectroscopy allowed unambiguous localized tracking throughout titration with each perturbant, demonstrating distinct behavior for each perturbant not previously revealed by heteronuclear NMR experiments.

Background/aims: Long-term lamivudine therapy can induce the emergence of lamivudine resistant hepatitis B virus (HBV) mutants. Clinically emergence of the mutant is expressed by the reappearance of disappeared HBV DNA in serum. Continued lamivudine treatment has been usually recommended in cases of viral breakthrough. However, the clinical outcome in patients with viral breakthrough is not clear. The aim of this study was to investigate the clinical course of chronic hepatitis B patients after viral breakthrough during lamivudine therapy., Methods: A total of 74 patients with chronic hepatitis B who showed viral breakthrough after at least 6 months of lamivudine treatment were included in this study. They had positive HBeAg and HBV DNA before treatment. The median follow-up duration after breakthrough was 13 months., Results: After viral breakthrough, only 8 patients (11%) maintained normal ALT levels and 66 patients (89%) showed elevation of ALT. 30 patients (41%) showed acute exacerbation of hepatitis (ALT increase over five-times upper normal limit). These acute exacerbations occurred within three months after breakthrough in 19 patients (63%). In the cases of acute exacerbation, 6 patients showed decompensated progression such as elevation of serum total bilirubin. One of them died of hepatic failure. A predictive factor for acute exacerbation was not found. HBeAg seroconversion occurred in 8 patients after viral breakthrough but their clinical course was highly variable., Conclusions: Chronic hepatitis B patients who had viral breakthrough during lamivudine therapy should be followed carefully and regularly in mind of potential clinical deterioration. New strategies are needed to manage the cases of acute exacerbation after viral breakthrough.

This study was designed to begin establishing the ecological validity of laboratory research indicating that nonretarded children's responses toward mentally retarded peers are positively affected by the retarded peers' competence in different areas. Groups of 3 children (1 retarded and 2 nonretarded fourth through sixth-graders) played a bean bag toss game in which the retarded child was either the best or an average player. Then children selected one of their two partners as a partner for a subsequent game and indicated their attitudes toward each peer and their attribution for each peer's performance. Retarded children who were the best players were selected as partners significantly more often than retarded children who were average players. Nonretarded children's attitudes toward retarded peers, however, were the same regardless of the retarded peers' performance. A relationship was also found between children's attributions of retarded peers' success to ability and their selection of the same peers as partners.

The ability of prosocial behavior attributes to ameliorate the negative attitudes often brought about by negative personal characteristics associated with mild and moderate mental retardation was assessed. Subjects (191 nonretarded fourth through sixth-grade boys and girls) viewed a videotape of either a nonretarded, mildly retarded, or moderately retarded target child who was reading. They then were read a story depicting the target as either socially competent, withdrawn, or aggressive. On three measures, children in general responded favorably toward retarded target children who were socially competent, neutrally to withdrawn targets and negatively to aggressive targets. They were most positive to the nonretarded, socially competent targets and most negative to the nonretarded, aggressive targets, however. Prosocial behavior attributes had a positive effect on children's attitudes and behavioral intentions toward retarded targets. Implications for future research, social skills training, and mainstreaming were discussed.

Effects of the labels "mentally retarded" and "retard" on fifth- and sixth-grade children's attitudes toward peers were studied. Results indicated that children's attitudes (feelings and behavioral intentions) were more positive toward the target child labeled "mentally retarded" than labeled "retard." The data also showed that children's reactions to the two labels were, in part, a function of the physical appearance and academic competence of the peer being rated. Children had the most negative attitudes toward a child labeled "retard" who appeared to be "normal." In contrast, children reacted favorably to the target child labeled "mentally retarded," even when he or she was academically incompetent. Finally, boys were more negative than were girls toward the target child, especially when the child was labeled "retard." Implications for the movement to abandon the use of labels were discussed.

How children's attitudes toward mentally retarded and nonretarded peers were affected by information highlighting the similarities and differences of those peers was assessed. Eighty fourth- through sixth-grade children viewed either a nonretarded, mildly retarded, or moderately retarded target child in two videotape vignettes. The first showed a target who was reading; the second, a target discussing interests. Children's attitudes and perceived similarity to the target were assessed. Results showed that children judged nonretarded peers more favorably than retarded peers, information about target peers' interests positively affected children's attitudes, children were able to see themselves as similar to retarded target peers, and children who saw themselves as similar to the target peer evaluated that peer more positively than children who did not perceive themselves as similar.

The protective effect of the label "mentally retarded" was tested to determine whether the label could help ameliorate the negative attitudes children have toward mentally retarded peers who exhibit poor social behavior. Nonretarded fourth through sixth graders (n = 126) viewed a videotape of a mildly retarded target child reading. The target was either labeled or not labeled "mentally retarded" and was depicted as either socially withdrawn or aggressive. Assessment of children's attitudes indicated that the label had a protective effect when the retarded child was withdrawn but only a very weak effect when the child was aggressive. This suggests a limit to the protective effect of the label. Results reaffirmed the necessity of examining labels in combination with child characteristics in order to understand more fully the effects of labels.

The relationship between the attitudes children express toward mentally retarded peers in laboratory settings and their social acceptance of such peers in their mainstream classrooms was examined. Forty-six fourth through sixth graders expressed their attitudes toward an unknown mentally retarded student presented in a videotape. They also indicated their social acceptance, rejection, or neglect of a mentally retarded peer in their classroom. A step-wise multiple regression analysis showed that children's attitudes toward the target child in the laboratory setting were related to their sociometric choices of the retarded classmate. Results supported previous indirect evidence of a relationship between children's attitudes toward retarded peers presented in a laboratory setting and their social acceptance of retarded peers mainstreamed in their classrooms.

The social relationships of 64 adolescents with moderate mental retardation from seven classes in a special day school were examined via two sociometric measures. Results indicated that the classes contained social structures similar to those found in regular classrooms for students without retardation. Students were selective in choosing friends and playmates, there was reciprocity in their friendship choices, and classes had popular and rejected students. Further, students frequently chose as friends members of the opposite sex, peers from other classes, and adults in the school and community. Implications for future research concerning the nature and development of friendships among students with mental retardation were discussed.