Ratiometric emission fluorescent pH probe for imaging of living cells in extreme acidity.

A novel ratiometric emission fluorescent probe, 1,1-dimethyl-2-[2-(quinolin-4-yl)vinyl]-1H-benzo[e]indole (QVBI), is facilely synthesized via ethylene bridging of benzoindole and quinoline. The probe exhibits ratiometric fluorescence emission (F(522nm)/F(630nm)) characteristics with pKa 3.27 and linear response to extreme-acidity range of 3.8-2.0. Also, its high fluorescence quantum yield (Φ = 0.89) and large Stokes shift (110 nm) are favorable. Moreover, QVBI possesses highly selective response to H(+) over metal ions and some bioactive molecules, good photostability, and excellent reversibility. The probe has excellent cell membrane permeability and is further applied successfully to monitor pH fluctuations in live cells and imaging extreme acidity in Escherichia coli cells without influence of autofluorescence and native cellular species in biological systems.

Dapagliflozin in heart failure and type 2 diabetes: Efficacy, cardiac and renal effects, safety.

BACKGROUND: Heart failure (HF), especially HF with reduced ejection fraction (HFrEF), presents complex challenges, particularly in the aging population where it often coexists with type 2 diabetes mellitus (T2DM). AIM: To analyze the effect of dapagliflozin treatment on cardiac, renal function, and safety in patients with HFrEF combined with T2DM. METHODS: Patients with T2DM complicated with HFrEF who underwent treatment in our hospital from February 2018 to March 2023 were retrospectively analyzed as the subjects of this study. The propensity score matching method was used, and a total of 102 eligible samples were scaled. The clinical efficacy of the two groups was evaluated at the end of the treatment, comparing the results of blood glucose, insulin, cardiac function, markers of myocardial injury, renal function indexes, and 6-min walk test (6MWT) before and after the treatment. We compared the occurrence of adverse effects on the treatment process of the two groups of patients. The incidence of adverse outcomes in patients within six months of treatment was counted. RESULTS: The overall clinical efficacy rate of patients in the study group was significantly higher than that of patients in the control group (P = 0.013). After treatment, the pancreatic beta-cell function index, left ventricular ejection fraction, and glomerular filtration rate of patients in the study group were significantly higher than control group (P < 0.001), while their fasting plasma glucose, 2-h postprandial glucose, glycosylated hemoglobin, insulin resistance index, left ventricular end-systolic diameter, left ventricular end-diastolic diameter, cardiac troponin I, creatine kinase-MB, N-terminal pro b-type natriuretic peptide, serum creatinine, and blood urea nitrogen were significantly lower than those of the control group. After treatment, patients in the study group had a significantly higher 6MWT than those in the control group (P < 0.001). Hypoglycemic reaction (P = 0.647), urinary tract infection (P = 0.558), gastrointestinal adverse effect (P = 0.307), respiratory disturbance (P = 0.558), and angioedema (P = 0.647) were not statistically different. There was no significant difference between the incidence of adverse outcomes between the two groups (P = 0.250). CONCLUSION: Dapagliflozin significantly enhances clinical efficacy, cardiac and renal function, and ambulatory capacity in patients with HFrEF and T2DM without an increased risk of adverse effects or outcomes.

Evaluation of salt tolerance of oat cultivars and the mechanism of adaptation to salinity.

Soil salinity is a threat to agricultural production worldwide. Oat (Avena sativa L.) is an irreplaceable crop in areas with fragile ecological conditions. However, there is a lack of research on salt tolerance evaluation of oat germplasm resources. Therefore, the purpose of this work was to evaluate the salt tolerance of oat cultivars and investigate the mechanism of salt-tolerant oat cultivars' adaptation to salinity. Salt tolerance of 100 oat cultivars was evaluated, and then two salt-tolerant cultivars and two salt-sensitive cultivars were used to compare their physiological responses and expression patterns of Na+- and K+-transport-related genes under salinity. Principal component analysis and membership function analysis had good predictability for salt tolerance evaluation of oat and other crops. The 100 oat cultivars were clustered into three categories, with three salt tolerance levels. Under saline condition, salt-tolerant cultivars maintained higher growth rate, leaf cell membrane integrity, and osmotic adjustment capability via enhancing the activities of antioxidant enzymes and accumulating more osmotic regulators. Furthermore, salt-tolerant cultivars had stronger capability to restrict root Na + uptake through reducing AsAKT1 and AsHKT2;1 expression, exclude more Na+ from root through increasing AsSOS1 expression, compartmentalize more Na + into root vacuoles through increasing AsNHX1 and AsVATP-P1 expression, and absorb more K+ through increasing AsKUP1 expression, compared with salt-sensitive cultivars. The evaluation procedure developed in this work can be applied for screening cereal crop cultivars with higher salt tolerance, and the elucidated mechanism of oat adaptation to salinity lays a foundation for identifying more functional genes related to salt tolerance.

Effects of Chinese herbal medicine Shenlong Decoction on mRNA expressions of matrix metalloproteinase-2 and tissue inhibitor of metalloproteinase-1 in lung tissue of rats with pulmonary fibrosis induced by bleomycin.

OBJECTIVE: To observe the expressions of matrix metalloproteinase-2 (MMP-2) and tissue inhibitor of metalloproteinase-1 (TIMP-1) in rats with pulmonary fibrosis (PF) induced by bleomycin, and to explore the mechanisms of Shenlong Decoction in preventing and treating PF. METHODS: A total of 230 Wistar rats were divided into normal control group, untreated group, prednisone group, and low-, medium- and high-dose Shenlong Decoction groups. Wistar rats were intratracheally injected with bleomycin to induce PF. From the 2nd day, rats in the normal control and untreated groups were lavaged with normal saline (NS), and rats in the other groups were lavaged with prepared Shenlong Decoction by the same amount. Hematoxylin-eosin (HE) staining and Masson staining were used to observe pathological changes in lung tissue at different time points, and to evaluate whether the model was successfully induced. Expressions of MMP-2 and TIMP-1 mRNAs in rats' lung tissue were measured by reverse transcription-polymerase chain reaction (RT-PCR). RESULTS: Expressions of MMP-2 and TIMP-1 mRNAs in lung tissue of rats were observed from all groups at each time point. In comparison with the normal control group, on the 7th day, the transcription levels of MMP-2 and TIMP-1 mRNAs, especially the former, of the untreated group increased significantly (P<0.05 or P<0.01). On the 14th day, the transcription levels of MMP-2 and TIMP-1 mRNAs kept rising, especially the latter (P<0.05 or P<0.01). On the 28th day, the transcription level of MMP-2 decreased a little, while the transcription level of TIMP-1 mRNA did not stop increasing (P<0.05 or P<0.01). Compared with the untreated group, decrease of the transcription levels of MMP-2 and TIMP-1 mRNAs were observed in the treatment groups, especially the former, and this effect continued to the 28th day with the medium-dose Shenlong Decoction group decreasing most obviously (P<0.05 or P<0.01). CONCLUSION: Shenlong Decoction may inhibit the expression of MMP-2 mRNA by up-regulating the expression of TIMP-1 mRNA so as to slow the progression of PF.

Multiple Traditional Chinese Medicine interventions for idiopathic pulmonary fibrosis: A protocol for systematic review and meta-analysis of overview.

BACKGROUND: The therapeutic strategies of idiopathic pulmonary fibrosis (IPF) tend to be comprehensive. Improving the major symptoms and quality of life (QoL) is as important as postponing the process of fibrosis. However, only pirfenidone and nintedanib conditionally recommended by guidelines and no definite proof indicate that they can significantly ameliorate the main symptoms and QoL of IPF sufferers. At present, multiple types of Traditional Chinese Medicine (TCM) interventions alone or in combination with conventional western medicine managements are widespreadly applied in IPF treatment, which seemingly have a promising clinical effect, especially in ameliorating the main symptoms and improving QoL. Subsequently, the number of relevant studies in systematic reviews(SRs) and meta-analyses of randomized controlled trials(RCTs) increased significantly. Hence, we plan to implement an overview to collect, evaluate, and summarize the results of these SRs. METHODS: An all-round literature retrieval will be conducted in 9 electronic databases, including PubMed, EMBASE, CINAHL, Cochrane Library, Epistemonikos, CNKI, CBM, Wanfang, and VIP. We will focus on the systematic review and meta-analysis of RCTs for multiple TCM interventions alone or in combination with routine western medicine measures in IPF treatment. The main outcomes we follow with interest include the improvement of major symptoms (cough, dyspnea) and QoL. Secondary outcomes will consist of minor symptoms improvement, clinical total effective rate, lung function, blood gas analysis, 6-minute walk text, adverse events, acute exacerbation, all-cause mortality, and IPF-related mortality. Two reviewers will independently select the SRs satisfactory with the enrolling criteria, extract key characteristics, and datas on predefined form, evaluate methodological quality by AMSTAR-2, ROBIS and PRISMA tools, and the quality of evidences adopting GRADE method. In case of any divergence will be reached an agreement by discussion or adjudicated by a third senior reviewer. We will perform a narrative synthesis of the proofs from SRs included. RESULTS: The findings of this overvew will be presented at relevant conferences and submitted for peer-review publication. CONCLUSIONS: We expect to obtain comprehensive and reliable evidence of IPF treated by diversified TCM interventions from the potential standard SRs, which may provide suggestions for future RCTs and SRs. REGISTRATION NUMBER: INPLASY 202080110.

Defective neuromuscular synapses in mice lacking amyloid precursor protein (APP) and APP-Like protein 2.

Biochemical and genetic studies place the amyloid precursor protein (APP) at the center stage of Alzheimer's disease (AD) pathogenesis. Although mutations in the APP gene lead to dominant inheritance of familial AD, the normal function of APP remains elusive. Here, we report that the APP family of proteins plays an essential role in the development of neuromuscular synapses. Mice deficient in APP and its homolog APP-like protein 2 (APLP2) exhibit aberrant apposition of presynaptic marker proteins with postsynaptic acetylcholine receptors and excessive nerve terminal sprouting. The number of synaptic vesicles at presynaptic terminals is dramatically reduced. These structural abnormalities are accompanied by defective neurotransmitter release and a high incidence of synaptic failure. Our results identify APP/APLP2 as key regulators of structure and function of developing neuromuscular synapses.

Reduced synaptic vesicle density and active zone size in mice lacking amyloid precursor protein (APP) and APP-like protein 2.

Although abnormal processing of amyloid precursor protein (APP) leads to early onset of Alzheimer's disease, the normal function of this protein is poorly understood. APP is widely expressed in axons, dendrites, and synapses in both central and peripheral nervous systems. Mice homozygous for APP or its homologue APP-like protein 2 (APLP2) null mutation (KO) are viable, but double mutants for APP and APLP2 deletions (DKO) are early postnatal lethal. To investigate the role of APP in synapse development, we compared the ultrastructure of submandibular ganglion synapses between DKO and littermate APLP2 KO mice at birth. Using serial electron microscopy, we found that the size of presynaptic boutons and the number of active zones per bouton were comparable in both strains of animals. However, the synaptic vesicle density, active zone size, and docked vesicle number per active zone were significantly reduced in DKO compared to those in APLP2 KO. These results indicate that the APP family of proteins plays an important role in regulating the formation and function of inter-neuronal synapses.

Comparative study for N and S doped carbon dots: Synthesis, characterization and applications for Fe(3+) probe and cellular imaging.

A facile and eco-friendly approach to prepare nitrogen(N)- and sulfur(S)-doped carbon dots (CDs) by one step microwave-assisted pyrolysis of the precursors with dl-malic acid as carbon source, ethanolamine and ethane-sulfonic acid as N and S dopants, respectively, was reported. Through the extensive investigation on morphology, chemical structures and optical properties of the carbon dots, it was found that the obtained CDs exhibited good luminescence stability, high resistance to photo bleaching and favorite solubility. Compared with undoped CDs, adding the N or S dopant could give rise to a slightly smaller particle size and a long fluorescence lifetime of CDs. Moreover, the optimal N-CDs was successfully employed as good multicolor cell imaging probes due to its fine dispersion in water, excitation-dependent emission, excellent biocompatibility and low toxicity. Besides, such N-CDs showed a wide detection range and excellent accuracy as fluorescent probe for Fe(3+) ions. This probe enabled the selective detection of Fe(3+) ions with a linear range of 6.0-200 µM and a limit of detection of 0.80 µM.

The Evolutionary History of R2R3-MYB Proteins Across 50 Eukaryotes: New Insights Into Subfamily Classification and Expansion.

R2R3-MYB proteins (2R-MYBs) are one of the main transcription factor families in higher plants. Since the evolutionary history of this gene family across the eukaryotic kingdom remains unknown, we performed a comparative analysis of 2R-MYBs from 50 major eukaryotic lineages, with particular emphasis on land plants. A total of 1548 candidates were identified among diverse taxonomic groups, which allowed for an updated classification of 73 highly conserved subfamilies, including many newly identified subfamilies. Our results revealed that the protein architectures, intron patterns, and sequence characteristics were remarkably conserved in each subfamily. At least four subfamilies were derived from early land plants, 10 evolved from spermatophytes, and 19 from angiosperms, demonstrating the diversity and preferential expansion of this gene family in land plants. Moreover, we determined that their remarkable expansion was mainly attributed to whole genome and segmental duplication, where duplicates were preferentially retained within certain subfamilies that shared three homologous intron patterns (a, b, and c) even though up to 12 types of patterns existed. Through our integrated distributions, sequence characteristics, and phylogenetic tree analyses, we confirm that 2R-MYBs are old and postulate that 3R-MYBs may be evolutionarily derived from 2R-MYBs via intragenic domain duplication.

The redox state of plastoquinone pool regulates state transitions via cytochrome b6f complex in Synechocystis sp. PCC 6803.

The effects of benzoquinone analogues, phenyl-1,4-benzoquinone (PBQ) and 2,5-dibromo-3-methyl-6-isopropyl-1,4-benzoquinone (DBMIB), on state transitions in Synechocystis sp. PCC 6803 were investigated. PBQ induced a transition from state 2 to state 1 in the absence of actinic light whereas DBMIB caused a state 2 transition. 3-(3,4-Dichlorophenyl)-1,1-dimethyl urea could not eliminate the effects of PBQ and DBMIB. These results imply that the redox state of the plastoquinone pool controls the state transitions in vivo and cytochrome b6f complex is involved in this process. As a working hypothesis, we propose that the occupancy of the quinol oxidation site and the movement of the Rieske protein may be pivotal in this regulation.

Effects of glycerol and high temperatures on structure and function of phycobilisomes in Synechocystis sp. PCC 6803.

The effects of glycerol and high temperatures on structure and function of phycobilisomes (PBSs) in vivo were investigated in a chlL deletion mutant of the cyanobacterium Synechocystis sp. PCC 6803. When the mutant was grown under light-activated heterotrophic growth conditions, it contained intact and functional PBSs, but essentially no chlorophyll and photosystems. So the structural and functional changes of the mutant PBSs in vivo can be handily detected by measurement of low temperature (77 K) fluorescence emission spectra. High concentration glycerol induced an obvious disassembly of PBSs and the dissociation of phycocyanins in the rod substructures into their oligomers and monomers. PBSs also disassembled at high temperatures and allophycocyanins were more sensitive to heat stress than phycocyanins. Our results demonstrate that the chlL(-) mutant strain is an advantageous model for studying the mechanisms of assembly and disassembly of protein complexes in vivo.

[Proliferation and differentiation of MC 3T3-E1 cells cultured on nanohydroxyapatite/chitosan composite scaffolds].

with chitosan in situ using a chemical method and a porous structure obtained was then lyophilized. Preosteoblast MC 3T3-E1 the scaffolds was examined after staining it with Wright's stain. Their proliferation was assessed using MTZ assay. After being Abstract Nanohydroxyapatite/chitosan composite scaffolds were fabricated and the proliferation and differentiation of preosteoblast MC 3T3-E1 on them were examined for the assessment of their biocompatibility. Nanohydroxyapatite was combined with chitosan in situ using a chemical method and a porous structure obtained was then lyophilized. Preosteoblast MC 333-E1 cells were inoculated into the porous composite scaffolds and chitosan scaffolds, respectively. The morphology of cells cultured on the scaffolds was examined after staining it with Wright's stain. Their proliferation was assessed using MTT assay. After being cultured in conditioned medium for 30 days, the cells' alkaline phosphatase activities on the scaffolds were studied in situ to compare their differentiation levelabout. Moreover, the alkaline phosphatase activities were assessed with a kit. The expression level of characteristic osteogenic gene was evaluated using Reverse Transcription-Polymerase Chain Reaction (RT-PCR). The results indicated that MC 3T3-E1 cells grown on the composite scaffolds showed a higher proliferation rate and spread better than that on chitosan scaffolds. The alkaline phosphatase stain results showed that the alkaline phosphatase activity of cells on composite scaffolds was significantly higher than that on the chitosan scaffolds. In addition, the quantitative examination of alkaline phosphatase activity indicated that the cells cultured on the composite scaffolds expressed an activity level about 8 times higher than that on chitosan scaffolds. Simultaneously, the osteogenic gene osteopontin (OPN) of cells cultured on composite scaffolds showed a higher expression level than that on chitosan scaffolds. Another osteogenic gene osteocalcin (OC) was expressed in cells cultured on composite scaffolds, whereas it was not detected in cells on chitosan scaffolds. The addition of nanohydroxyapatite in the scaffolds improved not only the proliferation but also the differentiation of preosteoblast cultured on them. The composite scaffolds showed good biocompatibility and bioactivity. These scaffolds would be promising in bone tissue engineering.

Characterization and osteoblast-like cell compatibility of porous scaffolds: bovine hydroxyapatite and novel hydroxyapatite artificial bone.

Three different porous scaffolds were tested. The first two were prepared by sintering bovine bone. The third scaffold was prepared using three-dimensional gel-lamination, a new rapid prototyping method, and was named as hydroxyapatite artificial bone. X-ray diffraction and Fourier transform infrared spectroscopy analysis confirmed that the samples were mainly highly crystalline hydroxyapatite ceramics. Scanning electron microscopy and mercury intrusion porosimetry measurement showed that the pores were interconnected and pore sizes ranged from several microns to hundreds of microns. Mouse osteoblast-like cells grown on the three scaffolds retained their characteristic morphology. Cell proliferation and differentiation, analyzed by methylthiazol tetrazolium (MTT) and alkaline phosphatase activity assays, were significantly higher on the hydroxyapatite artificial bone than on the other two scaffolds tested. All the scaffolds provided good attachment, proliferation and differentiation of bone cells. These results indicate that the scaffolds have a favorable interaction with cells, they support cell growth and functions, and therefore these scaffolds may have great potential as bone substitutes. The three-dimensional gel-lamination method is proven to be an attractive process to design and fabricate bone scaffolds with favorable properties, and therefore, has promising potential for bone repair applications.

Interaction of hydrogen peroxide with ribulose-1,5-bisphosphate carboxylase/oxygenase from rice.

The properties of rice-derived ribulose-1,5-bisphosphate carboxylase/oxygenase (rubisco) in different concentrations of hydrogen peroxide (H2O2) solutions have been studied. The results indicate that at low H2O2 concentrations (0.2-10 mM), the properties of rubisco (e.g., carboxylase activities, structure, and susceptibility to heat denaturation) change slightly. However, at higher H2O2 concentrations (10-200 mM), rubisco undergoes an unfolding process, including the loss of secondary and tertiary structure, forming extended hydrophobic interface, and leading to cross-links between large subunits. High concentrations of H2O2 can also result in an increase in susceptibility of rubisco to heat denaturation. Further pre-treatments with or without reductive reagents to rubisco show that the disulfide bonds in rubisco help to protect the enzyme from damage by H2O2 as well as other reactive oxygen species.