Terahertz polarization conversion and asymmetric transmission based on a liquid crystal integrated EIT metasurface.

We experimentally demonstrate a liquid crystal (LC)-integrated EIT metasurface for active THz polarization conversion and asymmetric transmission. By controlling the LC orientation under static magnetic field anchoring and an adjustable electric field, the device realizes the active control from the OFF state to the ON state, corresponding to the orthogonal polarization excitation modes of the EIT metasurface. Furthermore, based on the different polarization responses at forward and backward incidences, we achieve asymmetric transmission at the EIT peak and two nearby resonances, with its isolation actively manipulated by the external electric field. This study on dynamic polarization conversion and asymmetric transmission by a LC-integrated metasurface offers a promising route for active THz devices, applicable to THz communication, switching, and sensing systems.

Bifunctional ArsI Dioxygenase from Acidovorax sp. ST3 with Both Methylarsenite [MAs(III)] Demethylation and MAs(III) Oxidation Activities.

Methylated arsenicals, including highly toxic species, such as methylarsenite [MAs(III)], are pervasive in the environment. Certain microorganisms possess the ability to detoxify MAs(III) by ArsI-catalyzed demethylation. Here, we characterize a bifunctional enzyme encoded by the arsI gene from Acidovorax sp. ST3, which can detoxify MAs(III) through both the demethylation and oxidation pathways. Deletion of the 22 C-terminal amino acids of ArsI increased its demethylation activity while reducing the oxidation activity. Further deletion of 44 C-terminal residues enhanced the MAs(III) demethylation activity. ArsI has four vicinal cysteine pairs, with the first pair being necessary for MAs(III) demethylation, while at least one of the other three pairs contributes to MAs(III) oxidation. Molecular modeling and site-directed mutagenesis indicated that one of the C-terminal vicinal cysteine pairs is involved in modulating the switch between oxidase and demethylase activity. These findings underscore the critical role of the C-terminal region in modulating the enzymatic activities of ArsI, particularly in MAs(III) demethylation. This research reveals the structure-function relationship of the ArsI enzyme and advances our understanding of the MAs(III) metabolism in bacteria.

Comparison of bloodstream infections due to Corynebacterium striatum, MRSA, and MRSE.

BACKGROUND: Corynebacterium striatum (C. striatum), a common skin and mucosal colonizer, is increasingly considered as an opportunistic pathogen causing bloodstream infections (BSIs). This study aims to investigate the clinical features and outcomes of C. striatum-BSI. METHODS: We included hospitalized cases with C. striatum-positive blood cultures from January 2014 to June 2022 and classified them into C. striatum-BSI group and contamination group; Clinical characteristics, treatments, and outcomes were compared between the C. striatum-BSI group and contamination group, Methicillin-resistant Staphylococcus aureus (MRSA)-BSI and Methicillin-resistant Staphylococcus epidermidis (MRSE)-BSI. RESULTS: Fifty-three patients with positive C. striatum blood cultures were identified. Among them, 25 patients were classified as C. striatum-BSI, with 21 as contamination cases. And 62 cases of MRSA-BSI and 44 cases of MRSE-BSI were identified. Compared to the contaminated group, the C. striatum-BSI group had a shorter time to positivity of blood cultures (27.0 h vs. 42.5 h, P = 0.011). C. striatum-BSI group had a longer time to positivity (27 h) when compared to both the MRSA (20 h) and MRSE groups (19 h) (p < 0.05). Appropriate therapy within 24 h of BSI onset was significantly lower in the C. striatum group (28%) compared to the MRSA (64.5%) and MRSE (65.9%) groups (p < 0.005). The 28-day mortality was higher in the C. striatum group (52.0%) compared to the MRSA (25.8%) and MRSE (18.2%) groups.  CONCLUSIONS: Given the distinct characteristics of C. striatum-BSI, including a longer time to positivity than other Gram-positive bacteria and higher mortality rates, we suggest prescribing early appropriate antibiotics if C. striatum-BSI is suspected.

Therapeutic Efficacy of an Erythromycin-Loaded Coaxial Nanofiber Coating in a Rat Model of S. aureus-Induced Periprosthetic Joint Infection.

Implant surface nanofiber (NF) coatings represent an alternative way to prevent/treat periprosthetic joint infection (PJI) via local drug release. We developed and characterized a coaxial erythromycin (EM)-doped PLGA/PCL-PVA NF coating. The purpose of this study was to determine the efficacy of EM-NF coatings (EM0, no EM, EM100 (100 mg/mL), and EM1000 (1000 mg/mL) wt/wt) in a rat PJI model. A strong bond of the EM-NF coating to the surface of titanium (Ti) pins was confirmed by in vitro mechanical testing. Micro-computed tomography (mCT) analysis showed that both EM100 and EM1000 NF effectively reduced periprosthetic osteolysis compared to EM0 at 8 and 16 weeks after implantation. Histology showed that EM100 and EM1000 coatings effectively controlled infection and enhanced periprosthetic new bone formation. The bone implant contact (BIC) of EM100 (35.08%) was higher than negative controls and EM0 (3.43% and 0%, respectively). The bone area fraction occupancy (BAFO) of EM100 (0.63 mm2) was greater than controls and EM0 (0.390 mm2 and 0.0 mm2, respectively). The BAFO of EM100 was higher than that of EM1000 (0.3 mm2). These findings may provide a basis for a new implant surface fabrication strategy aimed at reducing the risks of defective osseointegration and PJI.

PLTS/ARAS-based financing risk resilience capability evaluation for fisheries enterprise: A case study of green transformation and upgrading.

Clearly delineating the key capabilities of organizational resilience for fisheries enterprises holds significant practical implications, as it can mitigate financing risks and foster the sustainable development of the fisheries industry. Based on the "dynamic capabilities perspective", this study constructs an analytical framework for the resilience capabilities of fisheries enterprises against financing risk. A hybrid method comprising the probabilistic linguistic term set, the decision-making trial and evaluation laboratory, and the additive ratio assessment is applied to a case study of Homey Group, examining the diverse pathways through which financing risk forms and impacts outcomes. The main findings are: (1) In the comprehensive assessment of the role of resilience capabilities in addressing the "Risk-Seeking-Decline Type" financing risk factors, market diversification and sustainable practices are accorded higher weights surpassing financial resources as the two most value-enhancing resilience capabilities. Enterprises characterized by a "Risk-Seeking-Loss Type" profile tend to assign higher weights to market diversification and technological infrastructure when evaluating financing risk resilience capabilities. (2) Regarding the key capabilities of organizational resilience, Homey Group possesses a weak risk management system for monitoring and evaluating significant risks and implementing control activities. (3) With regards to suggestions for improvement, it is advisable to delegate oversight of the risk identification process to a designated risk committee or specialists in risk management. The conclusions contribute to a deeper understanding of the nature and mechanism of resilience capabilities for fisheries enterprises and provides implications for risk management and sustainable development.

Multi-stage aeration regime to regulate organic conversion toward gas alleviation and humification in food waste digestate composting.

Aerobic composting has been considered as a pragmatic technique to convert food waste digestate into high-quality biofertiliser. Nevertheless, massive gaseous emission and immature product remain the primary challenges in food waste digestate composting. Thus, the performance of multi-stage aeration regimes to improve gaseous emissions and organic humification during food waste digestate composting was investigated in this study. In addition to continuous aeration with a constant intensity of 0.3 L kg·dry mass (DM)-1·min-1, two multi-stage decreased aeration regimes were designed as "0.3-0.2-0.1" and "0.3-0.1-0.1" L·kg·DM-1·min-1 from the thermophilic to cooling and then mature stages, respectively. Results showed that the decreased aeration regimes could alleviate nitrous oxide (N2O) and ammonia (NH3) emission and slightly enhance humification during composting. The alleviated N2O and NH3 emission were mainly contributed by abiotically reducing gaseous release potential as well as biotically inactivating denitrifers (Pusillimonas and Pseudidiomarina) and proliferating Atopobium to reduce nitrate availability under lower aeration supply. The "0.3-0.2-0.1 L kg·DM-1·min-1" regime exhibited a more excellent performance to alleviate N2O and NH3 emission by 27.5% and 16.3%, respectively. Moreover, the decreased aeration regimes also favored the enrichment of functional bacteria (Caldicoprobacter and Syntrophomonas) to accelerate lignocellulosic biodegradation and thus humic acid synthesis by 6.5%-11.2%. Given its better performance to improve gaseous emissions and humification, the aeration regime of "0.3-0.2-0.1 L kg·DM-1·min-1" are recommended in food waste digestate composting in practice.

Genome-wide association study of cerebellar white matter microstructure and genetic overlap with common brain disorders.

BACKGROUND: The cerebellum is recognized as being involved in neurocognitive and motor functions with communication with extra-cerebellar regions relying on the white matter integrity of the cerebellar peduncles. However, the genetic determinants of cerebellar white matter integrity remain largely unknown. METHODS: We conducted a genome-wide association analysis of cerebellar white matter microstructure using diffusion tensor imaging data from 25,415 individuals from UK Biobank. The integrity of cerebellar white matter microstructure was measured as fractional anisotropy (FA) and mean diffusivity (MD). Identification of independent genomic loci, functional annotation, and tissue and cell-type analysis were conducted with FUMA. The linkage disequilibrium score regression (LDSC) was used to calculate genetic correlations between cerebellar white matter microstructure and regional brain volumes and brain-related traits. Furthermore, the conditional/conjunctional false discovery rate (condFDR/conjFDR) framework was employed to identify the shared genetic basis between cerebellar white matter microstructure and common brain disorders. RESULTS: We identified 11 genetic loci (P < 8.3 × 10-9) and 86 genes associated with cerebellar white matter microstructure. Further functional enrichment analysis implicated the involvement of GABAergic neurons and cholinergic pathways. Significant polygenetic overlap between cerebellar white matter tracts and their anatomically connected or adjacent brain regions was detected. In addition, we report the overall genetic correlation and specific loci shared between cerebellar white matter microstructural integrity and brain-related traits, including movement, cognitive, psychiatric, and cerebrovascular categories. CONCLUSIONS: Collectively, this study represents a step forward in understanding the genetics of cerebellar white matter microstructure and its shared genetic etiology with common brain disorders.

Anoxygenic phototrophic arsenite oxidation by a Rhodobacter strain.

Microbially mediated arsenic redox transformations are key for arsenic speciation and mobility in rice paddies. Whereas anaerobic anoxygenic photosynthesis coupled to arsenite (As(III)) oxidation has been widely examined in arsenic-replete ecosystems, it remains unknown whether this light-dependent process exists in paddy soils. Here, we isolated a phototrophic purple bacteria, Rhodobacter strain CZR27, from an arsenic-contaminated paddy soil and demonstrated its capacity to oxidize As(III) to arsenate (As(V)) using malate as a carbon source photosynthetically. Genome sequencing revealed an As(III)-oxidizing gene cluster (aioXSRBA) encoding an As(III) oxidase. Functional analyses showed that As(III) oxidation under anoxic phototrophic conditions correlated with transcription of the large subunit of the As(III) oxidase aioA gene. Furthermore, the non-As(III) oxidizer Rhodobacter capsulatus SB1003 heterologously expressing aioBA from strain CZR27 was able to oxidize As(III), indicating that aioBA was responsible for the observed As(III) oxidation in strain CZR27. Our study provides evidence for the presence of anaerobic photosynthesis-coupled As(III) oxidation in paddy soils, highlighting the importance of light-dependent, microbe-mediated arsenic redox changes in paddy arsenic biogeochemistry.

Study of Huperzine A derivatives with extended protection against soman intoxication.

Pre-administration of huperzine A (Hup A) was validated to prevent poisoning from exposure to nerve agents (NAs) by reversibly inhibiting acetylcholinesterase (AChE). However, like the currently commonly used reversible inhibitors, Hup A has a short half-life and is unable to produce a long-term preventative effect. To extend the protective time of Hup A against NAs, 42 derivatives with a CN bond were designed based on the structure of Hup A in this study. All designed derivatives showed good binding capability with AChE via molecular docking. Six compounds (H3, H4, H11, H14, H16, and H25) with representative structures were selected for synthesis by Schiff base reaction, and their structures were stable. The modified Ellman's method showed the six compounds concentration-dependently inhibited AChE, and the half maximal inhibitory concentration (IC50) were higher than that of Hup A. Pretreatment of AChE with the derivatives significantly increased the IC50 of soman. In vivo experiments demonstrated H3, H4, H14, H16, and H25 had longer protective capacities against 1 × LD95 soman-induced death in mice than Hup A. The 12 h protective index showed that the protective ratios of H3, H4, H14 and H16 were 2.31, 1.85, 2.23 and 1.99 respectively, better than that of Hup A. The extended protection of the derivatives against soman may be explained by their transformation to Hup A in vivo. Furthermore, all six compounds showed lower acute oral toxicity than Hup A. Overall, our study provided an optional strategy to acquire pretreatment agents for NAs with extended action and low toxicity.

Widespread Distribution of the arsO Gene Confers Bacterial Resistance to Environmental Antimony.

Microbial oxidation of environmental antimonite (Sb(III)) to antimonate (Sb(V)) is an antimony (Sb) detoxification mechanism. Ensifer adhaerens ST2, a bacterial isolate from a Sb-contaminated paddy soil, oxidizes Sb(III) to Sb(V) under oxic conditions by an unknown mechanism. Genomic analysis of ST2 reveals a gene of unknown function in an arsenic resistance (ars) operon that we term arsO. The transcription level of arsO was significantly upregulated by the addition of Sb(III). ArsO is predicted to be a flavoprotein monooxygenase but shows low sequence similarity to other flavoprotein monooxygenases. Expression of arsO in the arsenic-hypersensitive Escherichia coli strain AW3110Δars conferred increased resistance to Sb(III) but not arsenite (As(III)) or methylarsenite (MAs(III)). Purified ArsO catalyzes Sb(III) oxidation to Sb(V) with NADPH or NADH as the electron donor but does not oxidize As(III) or MAs(III). The purified enzyme contains flavin adenine dinucleotide (FAD) at a ratio of 0.62 mol of FAD/mol protein, and enzymatic activity was increased by addition of FAD. Bioinformatic analyses show that arsO genes are widely distributed in metagenomes from different environments and are particularly abundant in environments affected by human activities. This study demonstrates that ArsO is an environmental Sb(III) oxidase that plays a significant role in the detoxification of Sb(III).

A propensity score matching analysis of gasless endoscopic transaxillary thyroidectomy with five-settlement technique versus conventional open thyroidectomy in patients with papillary thyroid microcarcinoma.

BACKGROUND: In a previous study, we proposed a novel anatomy-based five-settlement method for transaxillary endoscopic thyroidectomy (fs-TAT) for patients with papillary thyroid carcinoma. The safety of this new method has been reported in a retrospective study of a single cohort. The safety and short-term oncological outcome of this method was confirmed by comparing it with conventional open surgery (COT) in patients with papillary thyroid microcarcinoma. METHODS: The medical records of patients who underwent fs-TAT or COT by a single surgeon from February 2019 to December 2021 were reviewed retrospectively. All patients were diagnosed with papillary thyroid microcarcinoma and underwent lobectomy and ipsilateral central compartment neck dissection. Propensity score matching was used to compare the technical safety and short-term oncologic outcomes of fs-TAT and COT for the purpose of reducing potential selection bias. Reporting was consistent with the STROCSS 2021 guidelines. RESULT: After propensity score matching, 460 (fs-TAT: 230; COT: 230) patients remained in the study population. There were no significant differences in sex, age, tumor size, Hashimoto's thyroiditis, or tumor multifocality between the groups. The operative time was longer [104.5 (90.3, 120.0) vs. 62.0 (52.0, 76.0), P < 0.001] and the total postoperative drainage volume [135(90, 210) vs. 75 (55, 115), P < 0.001] was greater in the fs-TAT group than in the COT group. However, intraoperative bleeding [3.0 (2.0, 5.0) vs. 5.0 (5.0, 7.5), P < 0.001] was greater, and the median number of lymph nodes yielded [5.0 (2.3, 8.0) vs. 7.0 (5.0, 11.0), P < 0.001] was greater in the COT group than in the fs-TAT group. The groups exhibited no significant difference in the rate of complications (fs-TAT: 2.2% vs. COT: 2.6%, P = 0.856), rate of positive lymph nodes (fs-TAT: 32.2% vs. COT: 36.5%, P = 0.377), length of postoperative hospital stay (3 days vs. 3 days, P = 0.305) or total medical costs (26,936 vs. 26,549, P = 0.144). CONCLUSION: Compared to conventional open surgery, fs-TAT offered excellent safety and acceptable short-term oncological outcomes in a selected cohort of patients with papillary thyroid microcarcinoma.

PGC 1α-Mediates Mitochondrial Damage in the Liver by Inhibiting the Mitochondrial Respiratory Chain as a Non-cholinergic Mechanism of Repeated Low-Level Soman Exposure.

This work aimed to assess whether mitochondrial damage in the liver induced by subacute soman exposure is caused by peroxisome proliferator-activated receptor-gamma coactivator 1 alpha (PGC-1α) and whether PGC-1α regulates mitochondrial respiratory chain damage. Toxicity mechanism research may provide theoretical support for developing anti-toxic drugs in the future. First, a soman animal model was established in male Sprague-Dawley (SD) rats by subcutaneous soman injection. Then, liver damage was biochemically evaluated, and acetylcholinesterase (AChE) activity was also determined. Transmission electron microscopy (TEM) was performed to examine liver mitochondrial damage, and high-resolution respirometry was carried out for assessing mitochondrial respiration function. In addition, complex I-IV levels were quantitatively evaluated in isolated liver mitochondria by enzyme-linked immunosorbent assay (ELISA). PGC-1α levels were detected with a Jess capillary-based immunoassay device. Finally, oxidative stress was analyzed by quantifying superoxide dismutase (SOD), malondialdehyde (MDA), glutathione (GSH), oxidized glutathione (GSSG), and reactive oxygen species (ROS) levels. Repeated low-level soman exposure did not alter AChE activity, while increasing morphological damage of liver mitochondria and liver enzyme levels in rat homogenates. Complex I, II and I + II activities were 2.33, 4.95, and 5.22 times lower after treatment compared with the control group, respectively. Among complexes I-IV, I-III decreased significantly (p < 0.05), and PGC-1α levels were 1.82 times lower after soman exposure than in the control group. Subacute soman exposure significantly increased mitochondrial ROS production, which may cause oxidate stress. These findings indicated dysregulated mitochondrial energy metabolism involves PGC-1α protein expression imbalance, revealing non-cholinergic mechanisms for soman toxicity.

Does long-term care insurance reduce the disability among middle-aged and older adults? Evidence from China.

This study aimed to examine whether the implementation of Long-Term Care Insurance (LTCI) policy could reduce the disability among middle-aged and older adults in China, and to test the heterogeneity of the effects. Data came from four waves of the China Health and Retirement Longitudinal Study (CHARLS, 2011 to 2018). The Difference-In-Differences (DID) method and the panel data fixed effect model were used to estimate the effect of implementation of LTCI policy on disability among individuals aged 45 years and above. The LTCI policy had a positive impact on reducing disability among middle-aged and older people. Females, younger adults, city dwellers, and individuals living alone benefited the most from LTCI policy. The results provided empirical evidence for the implementation of LTCI policy in China and other similar countries as China. The implementation of LTCI policy should also pay more attention to inequity of the effects on reducing disability among different demographic groups.

Diagnostic and prognostic value of echocardiography in pulmonary hypertension: an umbrella review of systematic reviews and meta-analyses.

BACKGROUND: The role of echocardiography in the diagnostic and prognostic assessment of pulmonary hypertension (PH) has been widely studied recently. However, these findings have not undergone normative evaluation and may provide confusing evidence for clinicians. To evaluate and summarize existing evidence, we performed an umbrella review. METHODS: Systematic reviews and meta-analyses were searched in PubMed, Embase, Web of Science, and Cochrane Library from inception to September 4, 2022. The methodological quality of the included studies was assessed using Assessment of Multiple Systematic Reviews (AMSTAR), and the Grading of Recommendations Assessment, Development and Evaluation (GRADE) system was used to evaluate the quality of evidence. RESULTS: Thirteen meta-analyses (nine diagnostic and four prognostic studies) were included after searching four databases. The methodological quality of the included studies was rated as high (62%) or moderate (38%) by AMSTAR. The thirteen included meta-analyses involved a total of 28 outcome measures. The quality of evidence for these outcomes were high (7%), moderate (29%), low (39%), and very low (25%) using GRADE methodology. In the detection of PH, the sensitivity of systolic pulmonary arterial pressure is 0.85-0.88, and the sensitivity and specificity of right ventricular outflow tract acceleration time are 0.84. Pericardial effusion, right atrial area, and tricuspid annulus systolic displacement provide prognostic value in patients with pulmonary arterial hypertension with hazard ratios between 1.45 and 1.70. Meanwhile, right ventricular longitudinal strain has independent prognostic value in patients with PH, with a hazard ratio of 2.96-3.67. CONCLUSION: The umbrella review recommends echocardiography for PH detection and prognosis. Systolic pulmonary arterial pressure and right ventricular outflow tract acceleration time can be utilized for detection, while several factors including pericardial effusion, right atrial area, tricuspid annular systolic displacement, and right ventricular longitudinal strain have demonstrated prognostic significance. TRIAL REGISTRATION: PROSPERO (CRD42022356091), https://www.crd.york.ac.uk/prospero/ .

Transcriptomic Profiling of Tetrodotoxin-Induced Neurotoxicity in Human Cerebral Organoids.

Tetrodotoxin (TTX) is an exceedingly toxic non-protein biotoxin that demonstrates remarkable selectivity and affinity for sodium channels on the excitation membrane of nerves. This property allows TTX to effectively obstruct nerve conduction, resulting in nerve paralysis and fatality. Although the mechanistic aspects of its toxicity are well understood, there is a dearth of literature addressing alterations in the neural microenvironment subsequent to TTX poisoning. In this research endeavor, we harnessed human pluripotent induced stem cells to generate cerebral organoids-an innovative model closely mirroring the structural and functional intricacies of the human brain. This model was employed to scrutinize the comprehensive transcriptomic shifts induced by TTX exposure, thereby delving into the neurotoxic properties of TTX and its potential underlying mechanisms. Our findings revealed 455 differentially expressed mRNAs (DEmRNAs), 212 differentially expressed lncRNAs (DElncRNAs), and 18 differentially expressed miRNAs (DEmiRNAs) in the TTX-exposed group when juxtaposed with the control cohort. Through meticulous Gene Ontology (GO) annotation, Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis, and protein-protein interaction (PPI) analysis, we ascertained that these differential genes predominantly participate in the regulation of voltage-gated channels and synaptic homeostasis. A comprehensive ceRNA network analysis unveiled that DEmRNAs exert control over the expression of ion channels and neurocytokines, suggesting their potential role in mediating apoptosis.

A Heavy-atom-free Molecular Motif Based on Symmetric Bird-like Structured Tetraphenylenes with Room-Temperature Phosphorescence (RTP) Afterglow over 8 s.

In recent years, pure organic room-temperature phosphorescence (RTP) with highly efficient and long-persistent afterglow has drawn substantial awareness. Commonly, spin-orbit coupling can be improved by introducing heavy atoms into pure-organic molecules. However, this strategy will simultaneously increase the radiative and non-radiative transition rate, further resulting in dramatic decreases in the excited state lifetime and afterglow duration. Here in this work, a highly symmetric bird-like structure tetraphenylene (TeP), and its three symmetrical halogenated derivatives (TeP-F, TeP-Cl and TeP-Br) are synthesized, while their RTP properties and mechanisms are systematically investigated by both theoretical and experimental approaches. As the results, the rigid, highly twisted conformation of TeP restricts the non-radiative processes of RTP and gives rise to the enhancement of electron-exchange, which can contribute to the RTP radiation process. Despite the faint RTP of the bromine and chlorine-substituted ones (TeP-Br, TeP-Cl), the fluoro-substituted TeP-F exhibited a long phosphorescent lifetime up to 890 ms, corresponding to an extremely long RTP afterglow over 8 s, which could be incorporated into the best series of non-heavy-atom RTP materials reported in previous literature.

Comprehensive folding variations for protein folding.

The revelation of protein folding is a challenging subject in both discovery and description. Except for acquirement of accurate 3D structure in protein stable state, another big hurdle is how to discover structural flexibility for protein innate character. Even if a huge number of flexible conformations are known, difficulty is how to represent these conformations. A novel approach, protein structure fingerprint, has been developed to expose the comprehensive local folding variations, and then construct folding conformations for entire protein. The backbone of five amino acid residues was identified as a universal folden, and then a set of Protein Folding Shape Code (PFSC) was derived for completely covering folding space in alphabetic description. Sequentially, a database was created to collect all possible folding shapes of local folding variations for all permutation of five amino acids. Successively, Protein Folding Variation Matrix (PFVM) assembled all possible local folding variations along sequence for a protein, which possesses several prominent features. First, it showed the fluctuation with certain folding patterns along sequence which revealed how the protein folding was related the order of amino acids in sequence. Second, all folding variations for an entire protein can be simultaneously apprehended at a glance within PFVM. Third, all conformations can be determined by local folding variations from PFVM, so total number of conformations is no longer ambiguous for any protein. Finally, the most possible folding conformation and its 3D structure can be acquired according PFVM for protein structure prediction. Therefore, the protein structure fingerprint approach provides a significant means for investigation of protein folding problem.

A PadR family transcriptional repressor controls transcription of a trivalent metalloid resistance operon of Azospirillum halopraeferens strain Au 4.

Methylarsenite [MAs(III)] is a highly toxic arsenical produced by some microbes as an antibiotic. In this study, we demonstrate that a PadR family transcriptional regulator, PadRars , from Azospirillum halopraeferens strain Au 4 directly binds to the promoter region of the arsenic resistance (ars) operon (consisting of padRars , arsV, and arsW) and represses transcription of arsV and arsW genes involved in MAs(III) resistance. Quantitative reverse transcriptase PCR and transcriptional reporter assays showed that transcription of the ars operon is induced strongly by MAs(III) and less strongly by arsenite and antimonite. Electrophoretic mobility shift assays with recombinant PadRars showed that it represses transcription of the ars operon by binding to two inverted-repeat sequences within the ars promoter. PadRars has two conserved cysteine pairs, Cys56/57 and Cys133/134; mutation of the first pair to serine abolished the transcriptional response of the ars operon to trivalent metalloids, suggesting that Cys56/57 form a binding site for trivalent metalloids. Either C133S or C134S derivative responses to MAs(III) but not As(III) or Sb(III), suggesting that it is a third ligand to trivalent metalloids. PadRars represents a new type of repressor proteins regulating transcription of an ars operon involved in the resistance to trivalent metalloids, especially MAs(III).

Gel performance of surimi induced by various thermal technologies: A review.

Heating is a vital step in the gelation of surimi. Conventional water bath heating (WB) has the advantages of easy operation and low equipment requirements. However, the slow heat penetration during WB may lead to poor gel formation or gels prone to deterioration, especially with one-step heating. The two-step WB is time-consuming, and a large amount of water used tends to cause environmental problems. This review focuses on key factors affecting the quality of surimi gels in various heating technologies, such as surimi protein structure, chemical forces, or the activity of endogenous enzymes. In addition, the relationships between these factors and the gel performance of surimi under various heating modes are discussed by analyzing the heating temperature and heating rate. Compared with WB, the gel performance can be improved by controlling the heating conditions of microwave heating and ohmic heating, which are mainly achieved by changing the molecular structure of myofibrillar proteins or the activity of endogenous enzymes in surimi. Nevertheless, the novel thermal technologies still face several limitations and further research is needed to realize large-scale industrial production. This review provides ideas and directions for developing heat-induced surimi products with excellent gel properties.

Recent developments in maintaining gel properties of surimi products under reduced salt conditions and use of additives.

Salt is a necessary condition to produce a surimi product that is based on the gelation of salt-soluble myofibrillar proteins. Recently, there has been a growing concern among consumers to consume healthy foods due to the threat of several chronic diseases caused by an unhealthy diet. Methods of reducing salt content out of concern for health issues caused by excessive sodium intake may affect the gel properties of surimi, as can many health-oriented food additives. Several studies have investigated different strategies to improve the health characteristics of surimi products without decreasing gel properties. This review reports recent developments in this area and how the gel properties were successfully maintained under reduced-salt conditions and the use of additives. This review of recent studies presents a great deal of progress made in the health benefits of surimi and can be used as a reference for further development in the surimi product processing industry.