Brevetoxin Aptamer Selection and Biolayer Interferometry Biosensor Application.

Brevetoxins (PbTxs) are very potent marine neurotoxins that can cause an illness clinically described as neurologic shellfish poisoning (NSP). These toxins are cyclic polyether in chemistry and have increased their geographical distribution in the past 2 decades. However, the ethical problems as well as technical difficulties associated with currently employed analysis methods for marine toxins have spurred the quest for suitable alternatives to be applied in a regulatory monitoring regime. In this work, we reported the first instance of concurrent aptamer selection of Brevetoxin-1 (PbTx-1) and Brevetoxin-2 (PbTx-2) and constructed a biolayer interferometry (BLI) biosensor utilizing PbTx-1 aptamer as a specific recognition element. Through an in vitro selection process, we have, for the first time, successfully selected DNA aptamers with high affinity and specificity to PbTx-1 and PbTx-2 from a vast pool of random sequences. Among the selected aptamers, aptamer A5 exhibited the strongest binding affinity to PbTx-1, with an equilibrium dissociation constant (KD) of 2.56 µM. Subsequently, we optimized aptamer A5 by truncation to obtain the core sequence (A5-S3). Further refinement was achieved through mutations based on the predictions of a QGRS mapper, resulting in aptamer A5-S3G, which showed a significant increase in the KD value by approximately 100-fold. Utilizing aptamer A5-S3G, we fabricated a label-free, real-time optical BLI aptasensor for the detection of PbTx-1. This aptasensor displayed a broad detection range from 100 nM to 4000 nM PbTx-1, with a linear range between 100 nM and 2000 nM, and a limit of detection (LOD) as low as 4.5 nM. Importantly, the aptasensor showed no cross-reactivity to PbTx-2 or other marine toxins, indicating a high level of specificity for PbTx-1. Moreover, the aptasensor exhibited excellent reproducibility and stability when applied for the detection of PbTx-1 in spiked shellfish samples. We strongly believe that this innovative aptasensor offers a promising alternative to traditional immunological methods for the specific and reliable detection of PbTx-1.

Abnormal Interhemispheric Functional Connectivity in Acute Pericoronitis: A Resting-State MRI Study.

OBJECTIVE: Acute pericoronitis (AP) is a prevalent cause of odontogenic toothache which can significantly impact brain function. Previous research has predominantly concentrated on localized brain activity. However, the synergistic changes between brain hemispheres induced by toothache and resulting abnormal functional connectivity across the brain have not been comprehensively studied. METHODS: A total of 34 patients with AP and 34 healthy individuals, matched for age, sex, and education were recruited for this study. All participants underwent resting-state functional magnetic resonance imaging (rs-MRI) scans. The voxel mirror homotopic connectivity (VMHC) method was used to identify intergroup differences. Brain regions exhibiting statistically significant differences were selected as regions of interest for further functional connectivity analysis. The partial correlation method was utilized to assess the correlation between abnormal VMHC values in different regions and clinical parameters, with age and sex included as covariates. RESULTS: Patients with AP exhibited reduced VMHC values in the thalamus and elevated VMHC values in the inferior frontal gyrus compared with healthy controls. Subsequent functional connectivity analyses revealed extensive changes in functional networks, predominantly affecting the default, frontoparietal, cerebellar, and pain networks. CONCLUSION: Changes in functional patterns across these brain networks offer novel insights into the neurophysiological mechanisms underlying pain information processing.

Evaluation of levamlodipine benzenesulfonate compound I for embryo-fetal developmental toxicity in SD rats and genotoxicity.

In the present study, the effects of levamlodipine benzenesulfonate on the development of fertile Sprague-Dawley (SD) rats, their embryos, and littermates were assessed using an embryo-fetal developmental toxicity test. Maternal body weight reduction was observed at a dose of 20 mg/kg, but it recovered after treatment cessation. The 20 mg/kg dose group showed a skewed sex ratio in fetal rats, with a higher proportion of males. While some effects on fetal sternum development were observed at 20 mg/kg, no skeletal malformations were observed. No significant gross morphological abnormalities were detected in the dams (mothers), no significant embryotoxicity or foetotoxicity in fetal rats and no significant effects on fetal length and weight development at doses of 5 and 10 mg/kg. Genotoxicity was evaluated using a combination of the Ames test, the Chinese hamster ovary (CHO) cell chromosome aberration assay, and the ICR mouse bone marrow micronucleus test. The Ames test results indicated substantial bacteriostatic effects at doses of 500 and 5000 mg/dish, with no mutagenicity observed at doses of 0.5, 5, and 50 mg/dish. No significant effect on the aberration rate of CHO cell chromosomes was found at doses of 2.8, 5.6, and 11.2 mg/mL. In the ICR mouse micronucleus test, no micronucleus-inducing effect was observed at doses of 3.125, 6.25, and 12.5 mg/kg in each treatment group. In conclusion, under the conditions of this experiment, the no-observed-adverse-effect level (NOAEL) for developmental toxicity of levamlodipine benzenesulfonate in fertile SD rats, their embryos, and littermates was established to be 10 mg/kg/day. Levamlodipine benzenesulfonate did not exhibit significant genotoxicity.

Evaluation of XQ528 tartrate on embryo-fetus developmental toxicity in SD rats and genotoxicity.

The effects of XQ528 tartrate on the embryonic and fetal development of fertile Sprague-Dawley (SD) rats, along with their embryos and littermates, were evaluated using an embryo-fetus developmental toxicity assay. fertile SD rats exhibited no significant general toxic effects when administered doses of 0.25, 1.25, and 5.0 mg/kg intranasally from days 6 to 15 of gestation. The genotoxicity of the compound was evaluated through an amalgam of tests that included the Ames test, the Chinese hamster ovary (CHO) cell chromosome aberration test, and the micronucleus test in ICR mice. The results from the Ames test indicated non-mutagenicity at concentrations of 5000, 500, 50.0, 5.0, and 0.5 µg/dish across strains TA97, TA98, TA100, TA102, and TA1535. Additionally, the chromosomal aberration rates in CHO cells were not significantly altered at concentrations of 50.5, 101.0, and 202.0 µg/mL. No micronuclei induction was observed in ICR mice at dosage levels of 11.25, 22.50, and 45.00 mg/kg post intranasal administration. In conclusion, the no observed adverse effect level (NOAEL) for developmental toxicity of XQ528 tartrate in fertile SD rats, embryos, and littermates under the test conditions in this study was established at 5.0 mg/kg/day. Under these test conditions, XQ528 tartrate did not exhibit any significant genotoxic or carcinogenic potential.

Unmasking Protein Phosphatase 2A Regulatory Subunit B as a Crucial Factor in the Progression of Dilated Cardiomyopathy.

Dilated cardiomyopathy (DCM) is one of the major causes of heart failure. Although significant progress has been made in elucidating the underlying mechanisms, further investigation is required for clarifying molecular diagnostic and therapeutic targets. In this study, we found that the mRNA level of protein phosphatase 2 regulatory subunit B' delta (Ppp2r5d) was altered in the peripheral blood plasma of DCM patients. Knockdown of Ppp2r5d in murine cardiomyocytes increased the intracellular levels of reactive oxygen species (ROS) and inhibited adenosine triphosphate (ATP) synthesis. In vivo knockdown of Ppp2r5d in an isoproterenol (ISO)-induced DCM mouse model aggravated the pathogenesis and ultimately led to heart failure. Mechanistically, Ppp2r5d-deficient cardiomyocytes showed an increase in phosphorylation of STAT3 at Y705 and a decrease in phosphorylation of STAT3 at S727. The elevated levels of phosphorylation at Y705 in STAT3 triggered the upregulation of interleukin 6 (IL6) expression. Moreover, the decreased phosphorylation at S727 in STAT3 disrupted mitochondrial electron transport chain function and dysregulated ATP synthesis and ROS levels. These results hereby reveal a novel role for Ppp2r5d in modulating STAT3 pathway in DCM, suggesting it as a potential target for the therapy of the disease.

A multi-stimuli-responsive fluorescence material based on 1,8-naphthalimide.

A pair of 1,8-naphthalimides (NPIs) were designed and successfully synthesized through embellishing amino-containing NPI with 4-diethylaminosalicyladehyde and 4-diethylaminobenzaldehyde, respectively. Their structures were fully confirmed by 1H/13C NMR, HR-MS and FT-IR spectroscopic studies. Their photophysical properties were systematically investigated in different solvents of varied polarity, in THF/water mixtures with varying water fractions (fw), and in THF solvent with varying concentrations of NPIs. It inferred that the distinct differences in emission between two NPIs during self-assembled process could be ascribed that the hydroxyl-containing NPI allowed the excited-state intramolecular proton transfer process between -OH and CH=N units in the aggregation state. Interestingly, the solid of 4-diethylaminosalicyladehyde-functionalized NPI exhibited multi-stimuli-responsive fluorescence changes involving mechanofluorochromism and HCl/NH3 vapor stimulus-induced conversion. However, no remarkable change was observed in the photoluminescence (PL) spectra for the solid of 4-diethylaminobenzaldehyde-functionalized NPI under the stimuli of mechanical force and organic solvent.

Chromatographic purification of the plasmin-like enzyme from clamworm (Perinereis aibuhitensis Grub) and its fibrinolytic activity by metal ions.

In this study, fibrinolytic protease was isolated and purified from Perinereis aibuhitensis Grub, and the extraction process was optimized. The properties of the enzyme, such as the amino acid composition, thermal stability, optimal temperature, and pH, were investigated. After detoxification, proteins collected from fresh Clamworm (Perinereis aibuhitensis Grub) were concentrated via ammonium sulfate precipitation. The crude protease was purified using gel filtration resin (Sephadex G-100), anion exchange resin (DEAE-Sepharose FF), and hydrophobic resin (Phenyl Sepharose 6FF). The molecular weight of the protease was determined by polyacrylamide gel electrophoresis (SDS-PAGE). The optimum temperature and optimum pH of the protease were determined. The activity of crude protease in the 40-60% salt-out section was the highest, reaching 467.53 U/mg. The optimal process for purifying crude protein involved the application of DEAE-Sepharose FF and Phenyl Sepharose 6FF, which resulted in the isolation of a single protease known as Asp60-D1-P1 with the highest fibrinolytic activity; additionally, the enzyme activity was measured at 3367.76 U/mg. Analysis by Native-PAGE and SDS-PAGE revealed that the molecular weight of Asp60-D1-P1 was 44.5 kDa, which consisted of two subunits with molecular weights of 6.5 and 37.8 kDa, respectively. The optimum temperature for Asp60-D1-P1 was 40°C, and the optimal pH was 8.0.

Abnormal Functional Connectivity Intra- and Inter-Network in Resting-State Brain Networks of Patients with Toothache.

Objective: To separate the resting-state network of patients with dental pain using independent component analysis (ICA) and analyze abnormal changes in functional connectivity within as well as between the networks. Patients and Methods: Twenty-three patients with dental pain and 30 healthy controls participated in this study. We extracted the resting-state functional network components of both using ICA. Functional connectivity differences within 14 resting-state brain networks were analyzed at the voxel level. Directional interactions between networks were analyzed using Granger causality analysis. Subsequently, functional connectivity values and causal coefficients were assessed for correlations with clinical parameters. Results: Compared to healthy controls, we found enhanced functional connectivity in the left superior temporal gyrus of anterior protrusion network and the right Rolandic operculum of auditory network in patients with dental pain (p<0.01 and cluster-level p<0.05, Gaussian random field corrected). In contrast, functional connectivity of the right precuneus in the precuneus network was reduced, and were significantly as well as negatively correlated to those of the Visual Analogue Scale (r=-4.93, p=0.017), Hamilton Anxiety Scale (r=-0.46, p=0.027), and Hamilton Depression Scale (r=-0.563, p<0.01), using the Spearman correlation analysis. Regarding the causal relationship between resting-state brain networks, we found increased connectivity from the language network to the precuneus in patients with dental pain (p<0.05, false discovery rate corrected). However, the increase in causal coefficients from the verbal network to the precuneus network was independent of clinical parameters. Conclusion: Patients with toothache exhibited abnormal functional changes in cognitive-emotion-related brain networks, such as the salience, auditory, and precuneus networks, thereby offering a new imaging basis for understanding central neural mechanisms in dental pain patients.

Black Phosphorus Nanosheets Protect Neurons by Degrading Aggregative α-syn and Clearing ROS in Parkinson's Disease.

Although evidence indicates that the abnormal accumulation of α-synuclein (α-syn) in dopamine neurons of the substantia nigra is the main pathological feature of Parkinson's disease (PD), no compounds that have both α-syn antiaggregation and α-syn degradation functions have been successful in treating the disease in the clinic. Here, it is shown that black phosphorus nanosheets (BPNSs) interact directly with α-syn fibrils to trigger their disaggregation for PD treatment. Moreover, BPNSs have a specific affinity for α-syn through van der Waals forces. And BPNSs are found to activate autophagy to maintain α-syn homeostasis, improve mitochondrial dysfunction, reduce reactive oxygen species levels, and rescue neuronal death and synaptic loss in PC12 cells. It is also observed that BPNSs penetrate the blood-brain barrier and protect against dopamine neuron loss, alleviating behavioral disorders in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) induced mouse model and hA53T α-syn transgenic mice. Together, the study reveals that BPNSs have the potential as a novel integrated nanomedicine for clinical diagnosis and treatment of neurological diseases.

Structural characterization and potential anti-tumor activity of a polysaccharide from the halophyte Salicornia bigelovii Torr.

Plant polysaccharides are highly potent bioactive molecules. Clarifying the structural composition and bioactivities of plant polysaccharides will provide insights into their structure-activity relationships. Therefore, herein, we identified a polysaccharide produced by Salicornia bigelovii Torr. and analyzed the structure and anti-tumor activity of its component, SabPS-1. SabPS-1 was 3.24 × 104 Da, primarily composed of arabinose (24.96 %), galactose (30.39 %), and galacturonic acid (23.20 %), rhamnose (6.21 %), xylose (4.99 %), glucuronic acid (3.12 %), mannuronic acid (1.75 %), mannose (1.69 %), glucose (1.54 %), fucose (1.12 %), and guluronic acid (1.03 %). The backbone of SabPS-1 was a â†’ 4)-ß-D-GalpA-(1→, →5)-α-L-Araf-(1→, and→4)-ß-D-Galp-(1 â†’ molecule with a branched chain of α-L-Araf-(1 â†’ connected to sugar residues of →3,6)-ß-D-Galp-(1 â†’ in the O-3 position. SabPS-1 induced apoptosis and inhibited the growth of HepG-2 cells, with viability of 47.90 ± 4.14 (400 µg/mL), indicating anti-tumor activity. Apoptosis induced by SabPS-1 may be associated with the differential regulation of caspase 3, caspase 8, Bax, and Bcl-2. To the best of our knowledge, this is the first study to investigate the principal structures and anti-tumor biological activities of SabPS-1. Our findings demonstrated the excellent anti-tumor properties of SabPS-1, which will aid in the development of anti-tumor drugs utilizing Salicornia bigelovii Torr.

Visual detection and discrimination of nerve and blood agents using a dual-site fluorescent probe in living cells and mice.

Of all chemical warfare agents (CWAs), only nerve and blood agents cause massive mortality at low concentrations. To better detect and discriminate nerve and blood agents, a reliable detection method is desirable. We report a series of fluorescent probes for nerve and blood agent detection. Among the tested probes, SR-Pip detected nerve and blood agents quickly (within 10 s for nerve agents and 1 min for blood agents). SR-Pip coupled with nerve agent produced a weak orange fluorescence with good sensitivity [limit of detection (LOD)= 5.5 µM]. Upon reaction with blood agent, the fluorescence of SR-Pip changed from orange fluorescence to blue fluorescence with detection limits as low as 9.6 nM. This probe effectively visualised different concentrations of nerve agents in living cells and mice. A portable test kit using SR-Pip instantly detected nerve and blood agents. To the best of our knowledge, SR-Pip is the first fluorescent probe for nerve and blood agent detection.

Genome Mining Leads to Diverse Sesquiterpenes with Anti-inflammatory Activity from an Arctic-Derived Fungus.

With the advancement of bioinformatics, the integration of genome mining with efficient separation technology enables the discovery of a greater number of novel bioactive compounds. The deletion of the key gene responsible for triterpene cyclase biosynthesis in the polar strain Eutypella sp. D-1 instigated metabolic shunting, resulting in the activation of dormant genes and the subsequent production of detectable, new compounds. Fifteen sesquiterpenes were isolated from the mutant strain, with eight being new compounds. The structural elucidation of these compounds was obtained through a combination of HRESIMS, NMR spectroscopy, and ECD calculations, revealing six distinct skeleton types. Compound 7 possessed a unique skeleton of 5/10 macrocyclic ether structure. Based on the gene functions and newly acquired secondary metabolites, the metabolic shunting pathway in the mutant strain was inferred. Compounds 6, 8, 11, 14, and 15 exhibited anti-inflammatory effects without cytotoxicity through the release of nitric oxide from lipopolysaccharide-stimulated RAW264.7 cells. Notably, acorane-type sesquiterpene 8 inhibited nitric oxide production and modulated the MAPK and NLRP3/caspase-1 signaling pathways. Compound 8 also alleviated the CuSO4-induced systemic neurological inflammation symptoms in a transgenic fluorescent zebrafish model.

Functional role of circRNA CHRC through miR-431-5p/KLF15 signaling axis in the progression of heart failure.

Pathological myocardial hypertrophy is a common early clinical manifestation of heart failure, with noncoding RNAs exerting regulatory influence. However, the molecular function of circular RNAs (circRNAs) in the progression from cardiac hypertrophy to heart failure remains unclear. To uncover functional circRNAs and identify the core circRNA signaling pathway in heart failure, we construct a global triple network (microRNA, circRNA, and mRNA) based on the competitive endogenous RNA (ceRNA) theory. We observe that cardiac hypertrophy-related circRNA (circRNA CHRC), within the ceRNA network, is down-regulated in both transverse aortic constriction mice and Ang-II--treated primary mouse cardiomyocytes. Silencing circRNA CHRC increases cross-sectional cell area, atrial natriuretic peptide, and ß-myosin heavy chain levels in primary mouse cardiomyocytes. Further screening shows that circRNA CHRC targets the miR-431-5p/KLF15 axis implicated in heart failure progression in vivo and in vitro. Immunoprecipitation with anti-Ago2-RNA confirms the interaction between circRNA CHRC and miR-431-5p, while miR-431-5p mimics reverse Klf15 activation caused by circRNA CHRC overexpression. In summary, circRNA CHRC attenuates cardiac hypertrophy via sponging miR-431-5p to maintain the normal level of Klf15 expression.

α-Cyanostilbene-based Molecule with the Synergistical Mechanisms of AIE, ESIPT and TICT: A New Schiff Base Probe for Selective Detection of Fe3+ and Reversible Response to HCl/NH3 Vapor.

We designed and synthesized a new Schiff base probe, which incorporated the salicylaldehyde-analogue α-cyanostilbene and benzophenone hydrazone by the imine linkage. Its chemical structure was verified by FT-IR, MALDI-TOF-MS, HR-MS and 1H/13C NMR technologies. It could exhibit a red fluorescence based on the synergistical effects of aggregation-induce emission (AIE), excited-state intramolecular proton transfer (ESIPT) and twisted intramolecular charge-transfer (TICT) in the aggregation or solid states. Interestingly, the TLC-based test strip loaded with the target compound showed the reversible fluorescence response to amine/acid vapor and on-site visual fluorescence quenching response to Fe3+. In THF/water mixtures (fw = 90%, 10 µM, pH = 7.4), the detection limit (DL) and the binding constant (Ka) of the developed probe towards Fe3+ were evaluated as 5.50 × 10- 8 M and 1.69 × 105, respectively. The developed probe was successfully applied for the detection of Fe3+ with practical, reliable, and satisfying results.

Activation of Piezo1 increases the sensitivity of breast cancer to hyperthermia therapy.

Photothermal therapy (PTT) of nanomaterials is an emerging novel therapeutic strategy for breast cancer. However, there exists an urgent need for appropriate strategies to enhance the antitumor efficacy of PTT and minimize damage to surrounding normal tissues. Piezo1 might be a promising novel photothermal therapeutic target for breast cancer. This study aims to explore the potential role of Piezo1 activation in the hyperthermia therapy of breast cancer cells and investigate the underlying mechanisms. Results showed that the specific agonist of Piezo1 ion channel (Yoda1) aggravated the cell death of breast cancer cells triggered by heat stress in vitro. Reactive oxygen species (ROS) production was significantly increased following heat stress, and Yoda1 exacerbated the rise in ROS release. GSK2795039, an inhibitor of NADPH oxidase 2 (NOX2), reversed the Yoda1-mediated aggravation of cellular injury and ROS generation after heat stress. The in vivo experiments demonstrate the well photothermal conversion efficiency of TiCN under the 1,064 nm laser irradiation, and Yoda1 increases the sensitivity of breast tumors to PTT in the presence of TiCN. Our study reveals that Piezo1 activation might serve as a photothermal sensitizer for PTT, which may develop as a promising therapeutic strategy for breast cancer.

Genetic loss of Nrf1 and Nrf2 leads to distinct metabolism reprogramming of HepG2 cells by opposing regulation of the PI3K-AKT-mTOR signalling pathway.

As a vital hallmarker of cancer, the metabolic reprogramming has been shown to play a pivotal role in tumour occurrence, metastasis and drug resistance. Amongst a vast variety of signalling molecules and metabolic enzymes involved in the regulation of cancer metabolism, two key transcription factors Nrf1 and Nrf2 are required for redox signal transduction and metabolic homeostasis. However, the regulatory effects of Nrf1 and Nrf2 (both encoded by Nfe2l1 and Nfe2l2, respectively) on the metabolic reprogramming of hepatocellular carcinoma cells have been not well understood to date. Here, we found that the genetic deletion of Nrf1 and Nrf2 from HepG2 cells resulted in distinct metabolic reprogramming. Loss of Nrf1α led to enhanced glycolysis, reduced mitochondrial oxygen consumption, enhanced gluconeogenesis and activation of the pentose phosphate pathway in the hepatocellular carcinoma cells. By striking contrast, loss of Nrf2 attenuated the glycolysis and gluconeogenesis pathways, but with not any significant effects on the pentose phosphate pathway. Moreover, knockout of Nrf1α also caused fat deposition and increased amino acid synthesis and transport, especially serine synthesis, whilst Nrf2 deficiency did not cause fat deposition, but attenuated amino acid synthesis and transport. Further experiments revealed that such distinctive metabolic programming of between Nrf1α-/- and Nrf2-/- resulted from substantial activation of the PI3K-AKT-mTOR signalling pathway upon the loss of Nrf1, leading to increased expression of critical genes for the glucose uptake, glycolysis, the pentose phosphate pathway, and the de novo lipid synthesis, whereas deficiency of Nrf2 resulted in the opposite phenomenon by inhibiting the PI3K-AKT-mTOR pathway. Altogether, these provide a novel insight into the cancer metabolic reprogramming and guide the exploration of a new strategy for targeted cancer therapy.

Methyl α-D-galactopyranosyl-(1→3)-ß-D-galactopyranoside and methyl ß-D-galactopyranosyl-(1→3)-ß-D-galactopyranoside: Glycosidic linkage conformation determined from MA'AT analysis.

MA'AT analysis has been applied to two biologically-important O-glycosidic linkages in two disaccharides, α-D-Galp-(1→3)-ß-D-GalpOMe (3) and ß-D-Galp-(1→3)-ß-D-GalpOMe (4). Using density functional theory (DFT) to obtain parameterized equations relating a group of trans-O-glycosidic NMR spin-couplings to either phi (ϕ') or psi (ψ'), and experimental 3JCOCH, 2JCOC, and 3JCOCC spin-couplings measured in aqueous solution in 13C-labeled isotopomers, probability distributions of ϕ' and ψ' in each linkage were determined and compared to those determined by aqueous 1-µs molecular dynamics (MD) simulation. Good agreement was found between the MA'AT and single-state MD conformational models of these linkages for the most part, with modest (approximately <15°) differences in the mean values of ϕ' and ψ', although the envelope of allowed angles (encoded in circular standard deviations or CSDs) is consistently larger for ϕ' determined from MA'AT analysis than from MD for both linkages. The MA'AT model of the α-Galp-(1→3)-ß-Galp linkage agrees well with those determined previously using conventional NMR methods (3JCOCH values and/or 1H-1H NOEs), but some discrepancy was observed for the ß-Galp-(1→3)-ß-Galp linkage, which may arise from errors in the conventions used to describe the linkage torsion angles. Statistical analyses of X-ray crystal structures show ranges of ϕ' and ψ' for both linkages that include the mean angles determined from MA'AT analyses, although both angles adopt a wide range of values in the crystalline state, with ϕ' in ß-Galp-(1→3)-ß-Galp linkages showing greater-than-expected conformational variability.

Purification and Properties of a Plasmin-like Marine Protease from Clamworm (Perinereis aibuhitensis).

Marine organisms are a rich source of enzymes that exhibit excellent biological activity and a wide range of applications. However, there has been limited research on the proteases found in marine mudflat organisms. Based on this background, the marine fibrinolytic enzyme FELP, which was isolated and purified from clamworm (Perinereis aibuhitensis), has exhibited excellent fibrinolytic activity. We demonstrated the FELP with a purification of 10.61-fold by precipitation with ammonium sulfate, ion-exchange chromatography, and gel-filtration chromatography. SDS-PAGE, fibrin plate method, and LC-MS/MS indicated that the molecular weight of FELP is 28.9 kDa and identified FELP as a fibrinolytic enzyme-like protease. FELP displayed the maximum fibrinolytic activity at pH 9 (407 ± 16 mm2) and 50 °C (724 ± 27 mm2) and had excellent stability at pH 7-11 (50%) or 30-60 °C (60%), respectively. The three-dimensional structure of some amino acid residues of FELP was predicted with the SWISS-MODEL. The fibrinolytic and fibrinogenolytic assays showed that the enzyme possessed direct fibrinolytic activity and indirect fibrinolysis via the activation of plasminogen; it could preferentially degrade Aα-chains of fibrinogen, followed by Bß- and γ-chains. Overall, the fibrinolytic enzyme was successfully purified from Perinereis aibuhitensis, a marine Annelida (phylum), with favorable stability that has strong fibrinolysis activity in vitro. Therefore, FELP appears to be a potent fibrinolytic enzyme with an application that deserves further investigation.

Difluoromethylated Difunctionalization of Alkenes under Visible Light.

Difluoromethylated compounds usually act as bioisosteres for alcohol functional groups and show unique physicochemical and biological properties. The cyano-difluoromethylation of alkenes using 5-((difluoromethyl)sulfonyl)-1-phenyl-1H-tetrazole as a CF2H radical difluoromethyl precursor was developed to afford nitriles including a CF2H group. A low-cost, stable, easily handled 5-((difluoromethyl)sulfonyl)-1-methyl-1H-tetrazole (DFSMT) was synthesized and applied as the radical CF2H reagent. Using DFSMT as the radical CF2H precursor, the oxyl-difluoromethylation of alkenes was developed to obtain difluoromethylated ether products. All of the reactions showed good functional group tolerability. Initial mechanistic experiments indicated that the CF2H radical was involved as the key active intermediate.

Molecular origin and biological effects of exercise mimetics.

With the rapid development of sports science and molecular biology technology, academia refers to molecules or microorganisms that mimic or enhance the beneficial effects of exercise on the body, called "exercise mimetics." This review aims to clarify the concept and development history of exercise mimetics, and to define the concept of exercise mimetics by summarizing its characteristics and functions. Candidate molecules and drug targets for exercise mimetics are summarized, and the relationship between exercise mimetics and exercise is explained, as well as the targeting system and function of exercise mimetics. The main targeting systems for exercise mimetics are the exercise system, circulatory system, endocrine system, endocrine system, and nervous system, while the immune system is potential targeting systems. Finally, future research directions for exercise mimetics are discussed.