PHOSPHATE STARVATION RESPONSE1 (PHR1) interacts with JASMONATE ZIM-DOMAIN (JAZ) and MYC2 to modulate phosphate deficiency-induced jasmonate signaling in Arabidopsis.

Phosphorus (P) is a macronutrient necessary for plant growth and development. Inorganic phosphate (Pi) deficiency modulates the signaling pathway of the phytohormone jasmonate in Arabidopsis thaliana, but the underlying molecular mechanism currently remains elusive. Here, we confirmed that jasmonate signaling was enhanced under low Pi conditions, and the CORONATINE INSENSITIVE1 (COI1)-mediated pathway is critical for this process. A mechanistic investigation revealed that several JASMONATE ZIM-DOMAIN (JAZ) repressors physically interacted with the Pi signaling-related core transcription factors PHOSPHATE STARVATION RESPONSE1 (PHR1), PHR1-LIKE2 (PHL2), and PHL3. Phenotypic analyses showed that PHR1 and its homologs positively regulated jasmonate-induced anthocyanin accumulation and root growth inhibition. PHR1 stimulated the expression of several jasmonate-responsive genes, whereas JAZ proteins interfered with its transcriptional function. Furthermore, PHR1 physically associated with the basic helix-loop-helix (bHLH) transcription factors MYC2, MYC3, and MYC4. Genetic analyses and biochemical assays indicated that PHR1 and MYC2 synergistically increased the transcription of downstream jasmonate-responsive genes and enhanced the responses to jasmonate. Collectively, our study reveals the crucial regulatory roles of PHR1 in modulating jasmonate responses and provides a mechanistic understanding of how PHR1 functions together with JAZ and MYC2 to maintain the appropriate level of jasmonate signaling under conditions of Pi deficiency.

2-Phenylcyclopropylmethylamine (PCPMA) as a privileged scaffold for central nervous system drug design.

The use of privileged scaffolds in medicinal chemistry is an effective way to accelerate the drug discovery process, especially at the hit/lead optimization stage. 2-Phenylcyclopropylmethylamine (PCPMA) is a less commonly used chemical scaffold in medicinal chemistry, but many PCPMA-containing compounds exert therapeutic effects for various diseases, in particular central nervous system (CNS) diseases such as depression, schizophrenia, sleep disorder, and Parkinson's disease. The backbone of the PCPMA scaffold enables a unique structure of an amino group linked to a benzene ring through an alkyl linker, making it a useful template for the design of bioactive compounds especially for CNS drug targets including aminergic GPCRs and transporters. This review summarizes the medicinal chemistry studies of PCPMA-containing drugs and drug-like molecules, their mechanisms of action, and biological activities. We conclude that PCPMA is a unique and useful privileged scaffold for CNS drug design.

Discovery of potential small molecular SARS-CoV-2 entry blockers targeting the spike protein.

An epidemic of pneumonia caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is spreading worldwide. SARS-CoV-2 relies on its spike protein to invade host cells by interacting with the human receptor protein Angiotensin-Converting Enzymes 2 (ACE2). Therefore, designing an antibody or small-molecular entry blockers is of great significance for virus prevention and treatment. This study identified five potential small molecular anti-virus blockers via targeting SARS-CoV-2 spike protein by combining in silico technologies with in vitro experimental methods. The five molecules were natural products that binding to the RBD domain of SARS-CoV-2 was qualitatively and quantitively validated by both native Mass Spectrometry (MS) and Surface Plasmon Resonance (SPR). Anti-viral activity assays showed that the optimal molecule, H69C2, had a strong binding affinity (dissociation constant KD) of 0.0947 µM and anti-virus IC50 of 85.75 µM.

A new approach to estimation of the proportional hazards model based on interval-censored data with missing covariates.

This paper discusses the fitting of the proportional hazards model to interval-censored failure time data with missing covariates. Many authors have discussed the problem when complete covariate information is available or the missing is completely at random. In contrast to this, we will focus on the situation where the missing is at random. For the problem, a sieve maximum likelihood estimation approach is proposed with the use of I-spline functions to approximate the unknown cumulative baseline hazard function in the model. For the implementation of the proposed method, we develop an EM algorithm based on a two-stage data augmentation. Furthermore, we show that the proposed estimators of regression parameters are consistent and asymptotically normal. The proposed approach is then applied to a set of the data concerning Alzheimer Disease that motivated this study.

Carboxyl Transfer of α-Keto Acids toward Oxazolidinones via Decarboxylation/Fixation of Liberated CO2.

A novel strategy for the direct carboxyl transfer involving a decarboxylative A3 reaction of α-keto acids, primary amines, and alkynes has been developed under a Cu(I)/Cu(II) binary catalysis system. This multicomponent reaction provides a facile and efficient approach for the production of a diverse range of 2-oxazolidinones in moderate to excellent yields through a one-pot CO2 elimination-fixation procedure. The conciseness of the "CO2 recycling" process makes this ideal synthesis superior over classical CO2 utilization.

Synthetic Access to Secondary Propargylamines via a Copper-Catalyzed Oxidative Deamination/Alkynylation Cascade.

A novel and selective cascade reaction of primary amines and alkynes for the synthesis of the corresponding secondary propargylamines is described. This protocol proceeds with a CuBr2/TBHP system through a process of oxidative deamination of primary amines to imine and alkynylation, featuring a wide scope of substrates with good functional-group tolerance and operational simplicity. Additionally, the use of two different primary amines could also work smoothly using this protocol.

Initiation Condition of Hemodialysis Is Independently Associated with All-Cause Mortality in Maintenance Hemodialysis Patients: A Retrospective Study.

BACKGROUND: Despite the progression of dialysis techniques,  the mortality of hemodialysis (HD) patients is still high in China. Here, a retrospective study was performed to investigate the neglected risk factors of all-cause mortality during maintenance HD (MHD). METHODS: We investigated 117 MHD patients who died between 2011 and 2016 in the Second Xiangya Hospital of Central South University HD center. In order to analyze the risk factors of 48 months all-cause death, the methods of Kaplan-Meier and Cox regression were used. RESULTS: Multivariate analyses of adjusted age and gender showed that MHD patients with estimated glomerular filtration rate <7 or >10 mL/min/1.73 m2 and anemia (hemoglobin <100 g/L) at the initiation of dialysis are independently associated with the higher death risk. Using central venous catheter vascular access, cerebrovascular comorbidities, diabetes, low-flux dialyzer, and dialysis frequency ≤2 times weekly were also the independent risk factors of death within 48 months. CONCLUSIONS: This study indicated that the status of HD initiation is a risk factor of long-term survival in MHD patients, which were usually ignored for lacking of nephrology care prior and could potentially be identified and modified to improve the survival prognosis. Video Journal Club "Cappuccino with Claudio Ronco" at  https://www.karger.com/Journal/ArticleNews/223997?sponsor=52.

Rapamycin Enhances Repressed Autophagy and Attenuates Aggressive Progression in a Rat Model of IgA Nephropathy.

BACKGROUND: IgA nephropathy (IgAN) has been considered to be the most frequent form of primary glomerulonephritis that occurs worldwide with a variety of factors involved in its occurrence and development. The impact of autophagy in IgAN, however, remains partially unclear. This study was designed to investigate the effects of rapamycin in an IgAN model. METHOD: After establishing an IgAN rat model, SD rats were divided into 4 groups: control, control + rapamycin, IgAN, IgAN + rapamycin. Proteinuria and the pathological changes and the level of autophagy of kidney were texted. Identify the expression of phosphorylation and total mammalian target of rapamycin (mTOR) and s6k1 as well as cyclin D1 in the kidney of rats through Western blot and immunohistochemistry. RESULTS: With rapamycin treatment, we observed a significant reduction in the progression of proteinuria as well as alleviation of pathological lesions in IgAN rats. Besides, autophagy was inhibited, while the mTOR/S6k1 pathway was activated and expression of cyclin D1 was increased in IgAN. Rapamycin treatment increased autophagy and decreased the expression of cyclin D1. CONCLUSION: These results may suggest that mTOR-mediated autophagy inhibition may result in mesangial cell proliferation in IgAN.

Effects of RAAS Inhibitors in Patients with Kidney Disease.

Proteinuria and decline of renal function are associated with progression of kidney disease. The Renin Angiotensin Aldosterone System (RAAS) plays an important role in blood pressure regulation, fluid volume, and sodium balance. Overactivity of RAAS contributes to the pathogenesis of a variety of clinical conditions including progress of chronic kidney disease (CKD). This review summarizes the use of RAAS inhibitors as dual therapy or monotherapy in different stages of kidney disease. Experimental and clinical studies have demonstrated RAAS inhibitors prevent proteinuria, kidney fibrosis and slow decline of renal function and thus play a protective role in both early and end stages of kidney disease. While combination use of RAAS inhibitors showed higher efficiency compared with monotherapy, it is also associated with higher incidence of adverse events. Besides ACEI/ARBs, more mechanism research of mineralocorticoid receptor antagonists in kidney disease should be performed.

Confidence intervals construction for difference of two means with incomplete correlated data.

BACKGROUND: Incomplete data often arise in various clinical trials such as crossover trials, equivalence trials, and pre and post-test comparative studies. Various methods have been developed to construct confidence interval (CI) of risk difference or risk ratio for incomplete paired binary data. But, there is little works done on incomplete continuous correlated data. To this end, this manuscript aims to develop several approaches to construct CI of the difference of two means for incomplete continuous correlated data. METHODS: Large sample method, hybrid method, simple Bootstrap-resampling method based on the maximum likelihood estimates (B 1) and Ekbohm's unbiased estimator (B 2), and percentile Bootstrap-resampling method based on the maximum likelihood estimates (B 3) and Ekbohm's unbiased estimator (B 4) are presented to construct CI of the difference of two means for incomplete continuous correlated data. Simulation studies are conducted to evaluate the performance of the proposed CIs in terms of empirical coverage probability, expected interval width, and mesial and distal non-coverage probabilities. RESULTS: Empirical results show that the Bootstrap-resampling-based CIs B 1, B 2, B 4 behave satisfactorily for small to moderate sample sizes in the sense that their coverage probabilities could be well controlled around the pre-specified nominal confidence level and the ratio of their mesial non-coverage probabilities to the non-coverage probabilities could be well controlled in the interval [0.4, 0.6]. CONCLUSIONS: If one would like a CI with the shortest interval width, the Bootstrap-resampling-based CIs B 1 is the optimal choice.

Confidence interval construction for the difference between two correlated proportions with missing observations.

Under the assumption of missing at random, eight confidence intervals (CIs) for the difference between two correlated proportions in the presence of incomplete paired binary data are constructed on the basis of the likelihood ratio statistic, the score statistic, the Wald-type statistic, the hybrid method incorporated with the Wilson score and Agresti-Coull (AC) intervals, and the Bootstrap-resampling method. Extensive simulation studies are conducted to evaluate the performance of the presented CIs in terms of coverage probability and expected interval width. Our empirical results evidence that the Wilson-score-based hybrid CI and the Wald-type CI together with the constrained maximum likelihood estimates perform well for small-to-moderate sample sizes in the sense that (i) their empirical coverage probabilities are quite close to the prespecified confidence level, (ii) their expected interval widths are shorter, and (iii) their ratios of the mesial non-coverage to non-coverage probabilities lie in interval [0.4, 0.6]. An example from a neurological study is used to illustrate the proposed methodologies.

Confidence-interval construction for rate ratio in matched-pair studies with incomplete data.

Matched-pair design is often used in clinical trials to increase the efficiency of establishing equivalence between two treatments with binary outcomes. In this article, we consider such a design based on rate ratio in the presence of incomplete data. The rate ratio is one of the most frequently used indices in comparing efficiency of two treatments in clinical trials. In this article, we propose 10 confidence-interval estimators for the rate ratio in incomplete matched-pair designs. A hybrid method that recovers variance estimates required for the rate ratio from the confidence limits for single proportions is proposed. It is noteworthy that confidence intervals based on this hybrid method have closed-form solution. The performance of the proposed confidence intervals is evaluated with respect to their exact coverage probability, expected confidence interval width, and distal and mesial noncoverage probability. The results show that the hybrid Agresti-Coull confidence interval based on Fieller's theorem performs satisfactorily for small to moderate sample sizes. Two real examples from clinical trials are used to illustrate the proposed confidence intervals.

Structural basis of psychedelic LSD recognition at dopamine D1 receptor.

Understanding the kinetics of LSD in receptors and subsequent induced signaling is crucial for comprehending both the psychoactive and therapeutic effects of LSD. Despite extensive research on LSD's interactions with serotonin 2A and 2B receptors, its behavior on other targets, including dopamine receptors, has remained elusive. Here, we present cryo-EM structures of LSD/PF6142-bound dopamine D1 receptor (DRD1)-legobody complexes, accompanied by a ß-arrestin-mimicking nanobody, NBA3, shedding light on the determinants of G protein coupling versus ß-arrestin coupling. Structural analysis unveils a distinctive binding mode of LSD in DRD1, particularly with the ergoline moiety oriented toward TM4. Kinetic investigations uncover an exceptionally rapid dissociation rate of LSD in DRD1, attributed to the flexibility of extracellular loop 2 (ECL2). Moreover, G protein can stabilize ECL2 conformation, leading to a significant slowdown in ligand's dissociation rate. These findings establish a solid foundation for further exploration of G protein-coupled receptor (GPCR) dynamics and their relevance to signal transduction.

Discovery of LHQ490 as a highly selective fibroblast growth factor receptor 2 (FGFR2) inhibitor.

Fibroblast growth factor receptor 2 (FGFR2) represents an appealing therapeutic target for multiple cancers, yet no selective FGFR2 inhibitors have been approved for clinical use to date. Here, we report the discovery of a series of new selective, irreversible FGFR2 inhibitors. The representative compound LHQ490 potently inhibited FGFR2 kinase activity with an IC50 of 5.2 nM, and was >61-, >34-, and >293-fold selective against FGFR1, FGFR3, and FGFR4, respectively. LHQ490 also exhibited high selectivity in a panel of 416 kinases. Cell-based studies revealed that LHQ490 efficiently suppressed the proliferation of BaF3-FGFR2 cells with an IC50 value of 1.4 nM, and displayed >70- and >714-fold selectivity against BaF3-FGFR1 and the parental BaF3 cells, respectively. More importantly, LHQ490 potently suppressed the FGFR2 signaling pathways, selectively inhibited FGFR2-driven cancer cell proliferation, and induced apoptosis of FGFR2-driven cancer cells. Taken together, this study provides a potent and highly selective FGFR2 inhibitor for further development of FGFR2-targeted therapeutic agents.

The past, present, and future of ecogeographic isolation between closely related Aquilegia plants.

Quantifying the strength of the ecogeographic barrier is an important aspect of plant speciation research, and serves as a practical step to understanding the evolutionary trajectory of plants under climate change. Here, we quantified the extent of ecogeographic isolation in four closely related Aquilegia species that radiated in the Mountains of SW China and adjacent regions, often lacking intrinsic barriers. We used environmental niche models to predict past, present, and future species potential distributions and compared them to determine the degree of overlap and ecogeographic isolation. Our investigation found significant ecological differentiation in all studied species pairs except A. kansuensis and A. ecalacarata. The current strengths of ecogeographic isolation are above 0.5 in most cases. Compared with current climates, most species had an expanding range in the Last Glacial Maximum, the Mid Holocene, and under four future climate scenarios. Our results suggested that ecogeographic isolation contributes to the diversification and maintenance of Aquilegia species in the Mountains of northern and SW China and would act as an essential reproductive barrier in the future.

Molecular mechanism of phosphorous signaling inducing anthocyanin accumulation in Arabidopsis.

Anthocyanins, flavonoid compounds derived from secondary metabolic pathways, play important roles in various biological processes. Phosphorus (P) is an essential macroelement for plant growth and development, and P-starvation usually results in anthocyanin accumulation. However, the molecular mechanism of P deficiency promotes anthocyanin biosynthesis has not been well characterized. Here, we provided evidence that the P signaling core protein PHOSPHATE STARVATION RESPONSE1 (PHR1) is physically associate with transcription factors (TFs) involved in anthocyanidin biosynthesis, including PRODUCTION OF ANTHOCYANIN PIGMENTS1 (PAP1/MYB75), MYB DOMAIN PROTEIN 113 (MYB113) and TRANSPARENT TESTA 8 (TT8). PHR1 and its homologies positively regulated anthocyanin accumulation in Arabidopsis seedlings under P-deficient conditions. Disruption of PHR1 simultaneously rendered seedlings hyposensitive to limiting P, whereas the overexpression of PHR1 enhanced P- deficiency-induced anthocyanin accumulation. Genetic analysis demonstrated that 35S:PHR1-2HA-5 seedlings partially recovers the P deficiency insensitive phenotype of myb-RNAi and tt8 mutants. In summary, our study indicated that protein complexes formed by PHR1 and MBW complex directly mediate the process of P-deficiency-induced anthocyanin accumulation, providing a new mechanistic understanding of how P-deficient signaling depends on the endogenous anthocyanin synthesis pathway to promote anthocyanin accumulation in Arabidopsis.

[Study of tacrolimus intranasal treatment for allergic asthma in mice].

OBJECTIVE: To explore the efficacy of intranasal treatment by immunosuppressant tacrolimus for allergic asthma and its mechanism in mice. METHODS: 24 female BALB/c mice were randomly divided into 4 groups: group A (negative control), group B (model control), group C (low dose treatment), and group D (high dose treatment). Mice in group A were treated with saline (100 microl). Other groups were sensitized intraperitoneally with allergen extracts of Dermatophagoides farinae (Der f) absorbed to Al(OH)3 at day 0, 7, and 14. From day 28, groups A, B, C, and D were intranasally treated with saline, PBS, 0.01% tacrolimus, and 0.1% tacrolimus, respectively, once per day for 7 d, and followed by intranasal challenge with 50 microl Der f extracts in the mean time. 24 h after the last challenge, the airway hyper-responsiveness (AHR) were detected. At 48 h after the last challenge, the mice were sacrificed, the bronchoalveolar lavage fluid (BALF) was collected, the lungs and spleen were aseptically removed. The total cell number and cell classification of BALF were recorded. The level of interleukin-4 (IL-4), interleukin-5 (IL-5), interferon-gamma (IFN-gamma) in BALF and in spleen cells culture supernatants was detected by ELISA. The lung inflammation and mucus secretion were observed in mice by HE (haematoxylin and eosin) staining and AB (Alcian Blue) staining. RESULTS: Compared with group B, AHR (P < 0.05) and airway inflammation in group D significantly reduced. The number of total cells [(29.92 +/- 5.20) x 10(4)/ml] (P < 0.05) and eosinophils [(4.33 +/- 0.75) x 10(4)/ml] (P < 0.01) in group D greatly decreased than those of group B [(59.33 +/- 5.99) x 10(4)/ml and (22.67 +/- 5.65) x 10(4)/ml]. The level of IL-4 [(22.49 +/- 4.96) pg/ml] (P < 0.05), IL-5 [(43.90 +/- 13.15) pg/ml] (P < 0.01) and IFN-gamma [(10.17 +/- 1.09) pg/ml] (P < 0.05) in BALF significantly decreased (P < 0.05) than those of group B [(57.02 +/- 7.38), (133.49 +/- 15.63) and (15.32 +/- 3.23) pg/ml, respectively]. The level of IL-4 [(22.54 +/- 4.58) pg/ml], IL-5 [(3631 +/- 20.85) pg/ml] and IFN-gamma [(11.28 +/- 1.79) pg/ml] in spleen cell culture supernatant all significantly decreased (P < 0.05) than those of group B [(56.34 +/- 6.21), (72.3 +/- 6.23) and (18.82 +/- 1.88) pg/ml, respectively]. There was no significant difference between group C and group B. CONCLUSION: Tacrolimus shows certain immune therapeutic effect on dust mite sensitized mice, and this effect may be attributed to its inhibition on T lymphocyte factor secretion.

Homogeneity test of rate ratios in stratified matched-pair studies.

This paper investigates homogeneity test of rate ratios in stratified matched-pair studies on the basis of asymptotic and bootstrap-resampling methods. Based on the efficient score approach, we develop a simple and computationally tractable score test statistic. Several other homogeneity test statistics are also proposed on the basis of the weighted least-squares estimate and logarithmic transformation. Sample size formulae are derived to guarantee a pre-specified power for the proposed tests at the pre-given significance level. Empirical results confirm that (i) the modified score statistic based on the bootstrap-resampling method performs better in the sense that its empirical type I error rate is much closer to the pre-specified nominal level than those of other tests and its power is greater than those of other tests, and is hence recommended, whilst the statistics based on the weighted least-squares estimate and logarithmic transformation are slightly conservative under some of the considered settings; (ii) the derived sample size formulae are rather accurate in the sense that their empirical powers obtained from the estimated sample sizes are very close to the pre-specified nominal powers. A real example is used to illustrate the proposed methodologies.

A comparison of methods for the construction of confidence interval for relative risk in stratified matched-pair designs.

A stratified matched-pair study is often designed for adjusting a confounding effect or effect of different trails/centers/ groups in modern medical studies. The relative risk is one of the most frequently used indices in comparing efficiency of two treatments in clinical trials. In this paper, we propose seven confidence interval estimators for the common relative risk and three simultaneous confidence interval estimators for the relative risks in stratified matched-pair designs. The performance of the proposed methods is evaluated with respect to their type I error rates, powers, coverage probabilities, and expected widths. Our empirical results show that the percentile bootstrap confidence interval and bootstrap-resampling-based Bonferroni simultaneous confidence interval behave satisfactorily for small to large sample sizes in the sense that (i) their empirical coverage probabilities can be well controlled around the pre-specified nominal confidence level with reasonably shorter confidence widths; and (ii) the empirical type I error rates of their associated test statistics are generally closer to the pre-specified nominal level with larger powers. They are hence recommended. Two real examples from clinical laboratory studies are used to illustrate the proposed methodologies.

[Culture optimization and characterization of an alginate-lyase from Pseudoalteromonas sp. LJ1].

OBJECTIVES: The present work aimed to optimize the culture conditions to produce extracellular alginate-lyase by Pseudoalteromonas sp. LJ1. METHODS: A bacterial alginate-lyase producing strain LJ1 was isolated from Laminaria japonica by enrichment culture technique. The strain was identified based on phenotypic characters, fatty acid compositions and 16S rRNA gene sequencing. Culture conditions were optimized to produce the extracellular alginate-lyase by the single factor and orthogonal tests. RESULTS: Strain LJ1 was identified as Pseudoalteromonas sp.. The optimal medium components were: sodium alginate 3 g/L, (NH4)2SO4 3 g/L, NaCl 20 g/L, KH2PO4 0.1 g/L, CaCl2 0.1 g/L; The optimal culture conditions were: 25 ml medium in 250 mL Erlenmeyer flask, inoculum's volume 3%, shaking speed of 150 r/min, initial pH 7.5, at 28 degrees C for 24 h. The enzyme exhibited maximal activity at pH 7.6, 40 degrees C and NaCl 0.3 mol/L. The enzyme activity was improved by Mg2+, and inhibited by Co2+ and Zn2+ at 1 mol/L. CONCLUSIONS: Strain LJ1 was a novel alginate-lyase producing bacterium of Pseudoalteromonas.