Polyketides with different post-modifications from desert endophytic fungus Paraphoma sp

Three new polyketides 4,6,8-trihydroxy-5-methyl-3,4-dihydronaphthalen-1(2H)-one (1), 5,7-dihydroxy-3-(1-hydroxyethyl)-3,4-dimethylisobenzofuran-1(3H)-one (2) and 1-(4-hydroxy-6-methoxy-1,7-dimethyl-3-oxo-1,3-dihydroisobenzofuran-1-yl) ethyl acetate (3) together with seven known analogues (4-10) were isolated from desert endophytic fungus Paraphoma sp. The structures of these compounds were elucidated by analysis of NMR data. The absolute configuration of (1-3) was established on the basis of CD experiments. The possible biosynthetic pathway of compounds (1-10) was suggested, which implied that these secondary metabolites might be originated from polyketide biosynthesis with different post-modification reactions. Compounds 2, and 5-8 were evaluated for bioactivities against plant pathogen A. solani, whereas none of them displayed any biological effects. In addition, compounds 1, 2 and 5-10 were also tested for cytotoxic activities against three human cancer cell lines (HepG2 cells, MCF-7 cells and Hela cells) without biological effects.

Acceleration of sub-relativistic electrons with an evanescent optical wave at a planar interface

We report on a theoretical and experimental study of the energy transfer between an optical evanescent wave, propagating in vacuum along the planar boundary of a dielectric material, and a beam of sub-relativistic electrons. The evanescent wave is excited via total internal reflection in the dielectric by an infrared (λ = 2 μm) femtosecond laser pulse. By matching the electron propagation velocity to the phase velocity of the evanescent wave, energy modulation of the electron beam is achieved. A maximum energy gain of 800 eV is observed, corresponding to the absorption of more than 1000 photons by one electron. The maximum observed acceleration gradient is 19 ± 2 MeV/m. The striking advantage of this scheme is that a structuring of the acceleration element's surface is not required, enabling the use of materials with high laser damage thresholds that are difficult to nano-structure, such as SiC, Al₂O₃ or CaF₂.

Sexual Dimorphism: How Female Cells Win the Race

Sexual dimorphisms are established by sex determination pathways and are maintained during regeneration of adult tissues. Two recent studies in Drosophila elucidate the contribution of cell-autonomous and endocrine mechanisms to the establishment and maintenance of growth dimorphism in larvae and the adult intestine.

Genetic analysis of PITX3 variants in patients with essential tremor

BACKGROUND

A clinical overlap between essential tremor (ET) and Parkinson's disease (PD) has prompted investigation whether these disorders share common genetic factors. The paired-like homeodomain transcription factor 3 gene (PITX3) has been shown to play an important role for the differentiation and survival of midbrain dopaminergic neurons in the substantia nigra pars compacta. The preferential degeneration of those dopaminergic neurons is the pathological hallmark in PD.

AIMS OF THE STUDY

The purpose of this study was to evaluate whether PITX3 variants are related to susceptibility of ET in Chinese Han population.

METHODS

Genetic analysis of two variants rs3758549 and rs4919621 of the PITX3 gene was conducted in 200 Chinese Han patients with ET and 426 controls.

RESULTS

We did not identify any statistically significant difference in either genotypic or allelic frequencies of variants between the ET patients and control cohort (all P > 0.05). Haplotype analysis of two variants in the PITX3 gene showed no potential association between the haplotypes and risk of ET (all P > 0.05).

CONCLUSIONS

Our data suggest that PITX3 variants rs3758549 and rs4919621 are not associated with ET in Chinese Han population.

Optical gating and streaking of free electrons with sub-optical cycle precision

The temporal resolution of ultrafast electron diffraction and microscopy experiments is currently limited by the available experimental techniques for the generation and characterization of electron bunches with single femtosecond or attosecond durations. Here, we present proof of principle experiments of an optical gating concept for free electrons via direct time-domain visualization of the sub-optical cycle energy and transverse momentum structure imprinted on the electron beam. We demonstrate a temporal resolution of 1.2±0.3 fs. The scheme is based on the synchronous interaction between electrons and the near-field mode of a dielectric nano-grating excited by a femtosecond laser pulse with an optical period duration of 6.5 fs. The sub-optical cycle resolution demonstrated here is promising for use in laser-driven streak cameras for attosecond temporal characterization of bunched particle beams as well as time-resolved experiments with free-electron beams.

[Selection of peer educators for sex education program-based on data from social network analysis among college freshmen students]

Objective: Through combining the results from social network analysis and willingness of the key actors, peer educators for sex education among freshmen to select peer educators for sex education. Methods: Self-developed questionnaires were used to collect information on related demographics, egocentric social networks and whole class-based unit-network. Descriptive analysis was applied. UCINET 6 was used to conduct social network analysis and to draw the whole networking graphs. Results: Classmates appeared as the most important behavior intimate social network (95.8% claimed they could potentially borrow money from them, and 96.6% often went out with them) and were the most important members who could share privacy information with (91.6%) and consulting for private health information on (89.1%), among freshmen students in college. Finally, 17 freshmen were selected to have become peer educators, with 10 of them as the committee members in the class. Conclusion: Classmates formed the most important social network among freshmen students in college. Social network analysis could be used to help identify the suitable peer educators.

Identification of a PRX variant in a Chinese family with congenital cataract by exome sequencing

BACKGROUND

Congenital cataract is a common cause of childhood vision impairment or blindness with genetic and clinical heterogeneity. The aim of this study was to identify the disease-associated gene in a Chinese family with congenital cataract.

METHODS

A four-generation Chinese family with three enrolled patients suffering from congenital cataract was studied. Detailed family history and clinical data of all the members were collected and recorded. Exome sequencing was applied in the proband to screen potential genetic variants, and then Sanger sequencing was used to verify the variant within the family.

RESULTS

A heterozygous variant, c.3673G > A (p.V1225M), in the periaxin gene (PRX) was identified in three patients and two asymptomatic individuals of the family. The variant was absent in the other three unaffected family members and in 3290 ethnically matched in-house controls from BGI-Shenzhen.

CONCLUSIONS

By utilizing both exome sequencing and Sanger sequencing, we identified a missense variant in the PRX gene that is possibly associated with disease in this family. Our finding may broaden the spectrum of genes associated with congenital cataract, and may provide insights into lens development, pathogenic mechanism, future clinical genetic diagnosis and therapy of congenital cataract.

Cell fate conversion-from the viewpoint of small molecules and lineage specifiers

Mammalian development was generally considered a naturally unidirectional and irreversible process. However, pioneering work of recent decades has highlighted the plasticity of mammalian cells and implied the possibilities of manipulating cell fate in vitro. Pluripotent stem cells, which hold great potential for regenerative medicine, have been shown to be reprogrammed from differentiated cells either by somatic cell nuclear transfer or by ectopic expression of pluripotency factors. Nevertheless, it remained unknown whether the reprogramming could be accomplished without pluripotency genes. Recent studies show that lineage specifiers play an important role in orchestrating the process of restoring pluripotency by replacing pluripotency-associated transcription factors. Moreover, a combination of small molecules enables the acquisition of pluripotency from somatic cells without any transgenes, offering a tractable platform to precisely dissect the induction and maintenance of cell identity. Here, we will discuss recent scientific advances regarding the cell fate conversion mediated by small molecules or lineage specifiers, especially in the chemically induced somatic cell reprogramming process, and will provide new insights into the intermediate plastic state and "seesaw model" established by chemical approaches during reprogramming.

Commensurability Oscillations of Composite Fermions Induced by the Periodic Potential of a Wigner Crystal

When the kinetic energy of a collection of interacting two-dimensional (2D) electrons is quenched at very high magnetic fields so that the Coulomb repulsion dominates, the electrons are expected to condense into an ordered array, forming a quantum Wigner crystal (WC). Although this exotic state has long been suspected in high-mobility 2D electron systems at very low Landau level fillings (ν≪1), its direct observation has been elusive. Here we present a new technique and experimental results directly probing the magnetic-field-induced WC. We measure the magnetoresistance of a bilayer electron system where one layer has a very low density and is in the WC regime (ν≪1), while the other ("probe") layer is near ν=1/2 and hosts a sea of composite fermions (CFs). The data exhibit commensurability oscillations in the magnetoresistance of the CF layer, induced by the periodic potential of WC electrons in the other layer, and provide a unique, direct glimpse at the symmetry of the WC, its lattice constant, and melting. They also demonstrate a striking example of how one can probe an exotic many-body state of 2D electrons using equally exotic quasiparticles of another many-body state.

Coherent population transfer between uncoupled or weakly coupled states in ladder-type superconducting qutrits

Stimulated Raman adiabatic passage offers significant advantages for coherent population transfer between uncoupled or weakly coupled states and has the potential of realizing efficient quantum gate, qubit entanglement and quantum information transfer. Here we report on the realization of the process in the superconducting Xmon and phase qutrits—two ladder-type three-level systems in which the ground state population is coherently transferred to the second excited state via the dark state subspace. We demonstrate that the population transfer efficiency is no less than 96% and 67% for the two devices, which agree well with the numerical simulation of the master equation. Population transfer via stimulated Raman adiabatic passage is significantly more robust against variations of the experimental parameters compared with that via the conventional resonant π pulse method. Our work opens up a new venue for exploring the process for quantum information processing using the superconducting artificial atoms.

Quantum state engineering necessitates transfer between quantum states. Here the authors demonstrate coherent population transfer between un- or weakly-coupled states of solid state systems, superconducting Xmon and phase qutrits, using stimulated Raman adiabatic passage and microwave driving.

Cardiac Gab1 deletion leads to dilated cardiomyopathy associated with mitochondrial damage and cardiomyocyte apoptosis

A vital step in the development of heart failure is the transition from compensatory cardiac hypertrophy to decompensated dilated cardiomyopathy (DCM) during cardiac remodeling under mechanical or pathological stress. However, the molecular mechanisms underlying the development of DCM and heart failure remain incompletely understood. In the present study, we investigate whether Gab1, a scaffolding adaptor protein, protects against hemodynamic stress-induced DCM and heat failure. We first observed that the protein levels of Gab1 were markedly reduced in hearts from human patients with DCM and from mice with experimental viral myocarditis in which DCM developed. Next, we generated cardiac-specific Gab1 knockout mice (Gab1-cKO) and found that Gab-cKO mice developed DCM in hemodynamic stress-dependent and age-dependent manners. Under transverse aorta constriction (TAC), Gab1-cKO mice rapidly developed decompensated DCM and heart failure, whereas Gab1 wild-type littermates exhibited adaptive left ventricular hypertrophy without changes in cardiac function. Mechanistically, we showed that Gab1-cKO mouse hearts displayed severe mitochondrial damages and increased cardiomyocyte apoptosis. Loss of cardiac Gab1 in mice impaired Gab1 downstream MAPK signaling pathways in the heart under TAC. Gene profiles further revealed that ablation of Gab1 in heart disrupts the balance of anti- and pro-apoptotic genes in cardiomyocytes. These results demonstrate that cardiomyocyte Gab1 is a critical regulator of the compensatory cardiac response to aging and hemodynamic stress. These findings may provide new mechanistic insights and potential therapeutic target for DCM and heart failure.

NBR1 is dispensable for PARK2-mediated mitophagy regardless of the presence or absence of SQSTM1

Degradation of malfunctional mitochondria by mitophagy is a pivotal component of mitochondrial quality control to maintain cellular homeostasis. Mitochondrial clearance through the PINK1/PARK2 pathway is mediated by autophagic adaptor proteins. Previous studies revealed a significant involvement, but not an absolute requirement for SQSTM1 in PARK2-dependent mitophagy, suggesting that the existence of redundant adaptor proteins may compensate for the loss of SQSTM1. Here we investigated whether NBR1, a functional homolog of SQSTM1, has a role in PARK2-mediated mitophagy, either alone or as a compensatory mechanism. We showed that NBR1 does not appear to be required for mitochondrial clustering following mitochondrial depolarization. Moreover, we demonstrated that deletion of NBR1 alone or in combination with SQSTM1 does not prevent the degradation of damaged mitochondria. Our data suggest that NBR1 is dispensable for PARK2-dependent mitophagy and additional autophagic adaptor proteins, other than NBR1, are responsible for mitochondrial degradation in cells depleted of SQSTM1.

Sleep duration and snoring associate with hypertension and glycaemic control in patients with diabetes

AIMS

Few studies have analysed the effect of sleep duration and snoring on hypertension and glycaemic control in patients with diabetes. This study aims to investigate the relationship of sleep duration and snoring on prevalent hypertension and glycaemic control in people with diabetes.

METHODS

In the baseline survey of the REACTION study, 56 032 patients with diabetes were categorized into four groups according to self-reported sleep duration: < 6, 6-7.9, 8-8.9 and ≥ 9 h. Snoring frequency was evaluated as 'usually', 'occasionally' or 'never'. Hypertension was assessed by systolic blood pressure, diastolic blood pressure, self-reported previous diagnosis and antihypertensive medications. 'Good' glycaemic control was defined as HbA1c < 53 mmol/mol (7.0%) and 'poor' glycaemic control as HbA1c ≥ 53 mmol/mol (7.0%).

RESULTS

Controlling for potential confounders and intermediates, sleep ≥ 9 h relative to intermediate sleep (6-7.9 h) was significantly associated with prevalent hypertension (OR: 1.25, 95% CI: 1.18-1.32) and poor glycaemic control (OR: 1.11, 95% CI: 1.05-1.18), and a U-shaped association was found between sleep duration and prevalent hypertension (P for quadratic trend = 0.019). Usually snoring was positively associated with prevalent hypertension (OR: 1.30, 95% CI: 1.23-1.37), whereas the association between snoring and poor glycaemic control was only on the borderline of statistical significance.

CONCLUSIONS

Compared with a sleep duration of 6-7.9 h, longer sleep duration was associated with a higher prevalence of hypertension and poor glycaemic control in people with diabetes. Moreover, the relationship between sleep duration and prevalent hypertension was U-shaped. These findings may propose important public health implications for diabetes management.

The EIF4G1 gene and Parkinson's disease

Variants in the EIF4G1 gene have been recently identified to be responsible for autosomal dominant PD (PARK18), but its role in the PD-related neurodegeneration is unclear. Several EIF4G1 mutation/variants were found to be associated with PD, and functional studies have suggested that these variants may impair the ability of cells to rapidly and dynamically respond to stress, thus probably participating in the development of PD, and these indicated that EIF4G1 variants may play an important role in pathogenicity of PD, although the frequency is low. Further studies involving large sample size of patients with PD from diverse populations, as well as studies of EIF4G1 expression and in scaffold function, are warranted.

Diagnostic performance of diffusion-weighted MRI for detection of pelvic metastatic lymph nodes in patients with cervical cancer: a systematic review and meta-analysis

In recent years, diffusion-weighted (DW) MRI has emerged as a new technique for detecting the pelvic lymph metastases in patients with cervical cancer. The aim of this meta-analysis was to assess the diagnostic value of DW imaging (DWI) for benign/malignant discrimination of pelvic lymph nodes (LNs). Studies about DWI for the detection of metastatic LNs were searched in the PubMed, EMBASE, Web of Science, EBSCO, the Cochrane Library and three Chinese databases. Based on the extracted data, we determined pooled sensitivities, specificities and diagnostic odds ratios (DORs) across studies, calculated positive and negative likelihood ratios (LRs) and constructed summary receiver operating characteristic curves with area under the curve (AUC) and Q* obtained. We also analysed the heterogeneity between studies based on subgroup analysis, threshold effect and publication bias. In total, 15 studies involving 1021 patients met the inclusion criteria. The pooled sensitivity, specificity and DOR of DWI were 0.86 [95% confidence interval (CI), 0.84-0.89], 0.84 (95% CI, 0.83-0.86) and 47.21 (95% CI, 25.67-86.81), respectively. LR syntheses yielded overall positive LR of 6.55 (95% CI, 4.77-9.01) and negative LR of 0.17 (95% CI, 0.12-0.23). The AUC and Q* index were 0.9384 and 0.8754, respectively. The heterogeneity was relatively high between studies; however, there was no evidence for threshold effect and publication bias. DWI is beneficial in the pelvic nodal assessment in patients with cervical cancer. Large-scale, high-quality trials with standard protocols are required to evaluate its clinical value for discrimination of metastatic from non-metastatic pelvic LNs in patients with cervical cancer. Advances in knowledge include providing evidence to assess the role of DWI in nodal staging of cervical cancer.

Resveratrol regulates mitochondrial reactive oxygen species homeostasis through Sirt3 signaling pathway in human vascular endothelial cells

Mitochondrial reactive oxygen species (mtROS) homeostasis plays an essential role in preventing oxidative injury in endothelial cells, an initial step in atherogenesis. Resveratrol (RSV) possesses a variety of cardioprotective activities, however, little is known regarding the effects of RSV on mtROS homeostasis in endothelial cells. Sirt3 is a mitochondrial deacetylase, which plays a key role in mitochondrial bioenergetics and is closely associated with oxidative stress. The goal of the study is to investigate whether RSV could attenuate oxidative injury in endothelial cells via mtROS homeostasis regulation through Sirt3 signaling pathway. We found that pretreatment with RSV suppressed tert-butyl hydroperoxide (t-BHP)-induced oxidative damage in human umbilical vein endothelial cells (HUVECs) by increasing cell viability, inhibiting cell apoptosis, repressing collapse of mitochondrial membrane potential and decreasing mtROS generation. Moreover, the enzymatic activities of isocitrate dehydrogenase 2 (IDH2), glutathione peroxidase (GSH-Px) and manganese superoxide dismutase (SOD2) as well as deacetylation of SOD2 were increased by RSV pretreatment, suggesting RSV notably enhanced mtROS scavenging in t-BHP-induced endothelial cells. Meanwhile, RSV remarkably reduced mtROS generation by promoting Sirt3 enrichment within the mitochondria and subsequent upregulation of forkhead box O3A (FoxO3A)-mediated mitochondria-encoded gene expression of ATP6, CO1, Cytb, ND2 and ND5, thereby leading to increased complex I activity and ATP synthesis. Furthermore, RSV activated the expressions of phosphorylated adenosine monophosphate-activated protein kinase (p-AMPK), peroxisome proliferator-activated receptor gamma coactivator-1α (PGC-1α) and Sirt3, as well as estrogen-related receptor-α (ERRα)-dependent Sirt3 mRNA transcription, which were abolished in the presence of AMPK inhibitor and AMPK, PGC-1α or Sirt3 siRNA transfection, indicating the effects of RSV on mtROS homeostasis regulation were dependent on AMPK-PGC-1α-ERRα-Sirt3 signaling pathway. Our findings indicated a novel mechanism that RSV-attenuated oxidative injury in endothelial cells through the regulation of mtROS homeostasis, which, in part, was mediated through the activation of the Sirt3 signaling pathway.

Subtypes of major depression: latent class analysis in depressed Han Chinese women

BACKGROUND

Despite substantial research, uncertainty remains about the clinical and etiological heterogeneity of major depression (MD). Can meaningful and valid subtypes be identified and would they be stable cross-culturally?

METHOD

Symptoms at their lifetime worst depressive episode were assessed at structured psychiatric interview in 6008 women of Han Chinese descent, age ⩾ 30 years, with recurrent DSM-IV MD. Latent class analysis (LCA) was performed in Mplus. RESULTS; Using the nine DSM-IV MD symptomatic A criteria, the 14 disaggregated DSM-IV criteria and all independently assessed depressive symptoms (n = 27), the best LCA model identified respectively three, four and six classes. A severe and non-suicidal class was seen in all solutions, as was a mild/moderate subtype. An atypical class emerged once bidirectional neurovegetative symptoms were included. The non-suicidal class demonstrated low levels of worthlessness/guilt and hopelessness. Patterns of co-morbidity, family history, personality, environmental precipitants, recurrence and body mass index (BMI) differed meaningfully across subtypes, with the atypical class standing out as particularly distinct.

CONCLUSIONS

MD is a clinically complex syndrome with several detectable subtypes with distinct clinical and demographic correlates. Three subtypes were most consistently identified in our analyses: severe, atypical and non-suicidal. Severe and atypical MD have been identified in multiple prior studies in samples of European ethnicity. Our non-suicidal subtype, with low levels of guilt and hopelessness, may represent a pathoplastic variant reflecting Chinese cultural influences.

A randomized study evaluating cinacalcet to treat hypercalcemia in renal transplant recipients with persistent hyperparathyroidism

Persistent hyperparathyroidism (HPT) after kidney transplantation (KTx) is associated with hypercalcemia, hypophosphatemia and abnormally high levels of parathyroid hormone (PTH). In this randomized trial, cinacalcet was compared to placebo for the treatment of hypercalcemia in adult patients with persistent HPT after KTx. Subjects were randomized 1:1 to cinacalcet or placebo with randomization stratified by baseline corrected total serum calcium levels (≤11.2 mg/dL [2.80 mmol/L] or >11.2 mg/dL [2.80 mmol/L]). The primary end point was achievement of a mean corrected total serum calcium value<10.2 mg/dL (2.55 mmol/L) during the efficacy period. The two key secondary end points were percent change in bone mineral density (BMD) at the femoral neck and absolute change in phosphorus; 78.9% cinacalcet- versus 3.5% placebo-treated subjects achieved the primary end point with a difference of 75.4% (95% confidence interval [CI]: 63.8, 87.1), p<0.001. There was no statistical difference in the percent change in BMD at the femoral neck between cinacalcet and placebo groups, p=0.266. The difference in the change in phosphorus between the two arms was 0.45 mg/dL (95% CI: 0.26, 0.64), p<0.001 (nominal). No new safety signals were detected. In conclusion, hypercalcemia and hypophosphatemia were effectively corrected after treatment with cinacalcet in patients with persistent HPT after KTx.

Meta-analysis of diagnostic value of 18F-FDG PET or PET/CT for detecting lymph node and distant metastases in patients with nasopharyngeal carcinoma

OBJECTIVE

We performed this meta-analysis to comprehensively assess the diagnostic performance of positron emission tomography (PET) or PET/CT for detecting lymph node and distant metastases in patients with nasopharyngeal carcinoma (NPC).

METHODS

Through a search of four English and three Chinese databases (January 1990 to June 2013), pooled estimated sensitivity, specificity and diagnostic odds ratio (DOR) were calculated based on the data extracted from the included studies. We also constructed summary receiver operating characteristic curves, with the area under the curve (AUC) and obtained the Q* index. Heterogeneity and subgroup analysis were also performed.

RESULTS

In total, 18 articles consisting 20 studies were included in this meta-analysis. On a per-patient basis, the overall pooled estimates for sensitivity and specificity of PET or PET/CT in N and M staging of NPC were 0.89 [95% confidence interval (CI), 0.86-0.91] and 0.96 (95% CI, 0.95-0.96), respectively. The overall DOR, AUC and Q* index were 162.07 (95% CI, 90.72-289.55), 0.9689 and 0.9181, respectively. Subgroup analysis showed that AUC and Q* index were 0.9734 and 0.9255 for N staging and 0.9715 and 0.9223 for M staging, respectively.

CONCLUSION

The present meta-analysis showed that PET or PET/CT has excellent diagnostic performance for detecting lymph node and distant metastases in patients with NPC.

ADVANCES IN KNOWLEDGE

To provide evidence to assess the role of PET or PET/CT in staging of NPC.