Melatonin suppresses serum starvation-induced autophagy of ovarian granulosa cells in premature ovarian insufficiency.

OBJECTIVES: Premature ovarian insufficiency (POI) refers to the decline and cessation of ovarian functions in women under 40 years of age. Melatonin (MT) acts as a protective for the ovary. This study elucidated the role of MT in autophagy of granulosa cells (GCs) in POI via modulating the phosphatidylinositol-3-kinase (PI3K)-Akt-mammalian target of rapamycin (mTOR) pathway. METHODS: The expression levels of microRNA (miR)-15a-5p, signal transducer and activator of transcription 3 (Stat3), and relevant hormones in the clinically collected serum samples of POI patients and healthy controls were examined. Human ovarian granulosa-like tumor cells (KGN) underwent serum starvation (SS) treatment to induce POI cell models and then received MT treatment. The expression levels of miR-15a-5p, Stat3, p-PI3K/PI3K, p-Akt/Akt, and p-mTOR/mTOR in KGN cells were tested via quantitative real-time polymerase chain reaction and Western blotting. KGN cell viability was assessed by MTT assay and the protein levels of autophagy-related markers Beclin-1, microtubule-associated protein light chain 3 II/I, and p62 were detected by Western blotting. The binding relation between miR-15a-5p and Stat3 was verified via the dual-luciferase reporter gene assay. Functional rescue experiments were performed to probe the underlying role of miR-15a-5p/Stat3/the PI3K-Akt-mTOR pathway in KGN cell autophagy. RESULTS: miR-15a-5p was increased whilst Stat3 was decreased in the serum of POI patients and SS-induced KGN cells. MT inhibited miR-15a-5p and Stat3, activated the PI3K-Akt-mTOR pathway, and repressed cell autophagy in SS-induced KGN cells. miR-15a-5p targeted and repressed Stat3 expression. Upregulation of miR-15a-5p or downregulation of Stat3 or the PI3K-Akt-mTOR pathway promoted KGN cell autophagy. CONCLUSION: MT suppressed miR-15a-5p and activated Stat3 and the PI3K-Akt-mTOR pathway, finally impeding SS-induced autophagy of GCs.

Molecular dynamics simulations on fullerene surfactants with different charges at the air-water interface.

The interfacial activity of fullerene surfactants at the air-water interface is studied via molecular dynamics and metadynamics simulations. Fullerene surfactants with different charges show different surface activity. Meanwhile, studies show that fullerene surfactants with zero or one positive charge show interesting interface behaviour, i.e. the hydrophobic fullerene of the fullerene surfactant with zero charge orients to bulk water while the fullerene surfactant with one positive charge can be a hydrophilic and hydrophobic rotator at the air-water interface.

Electronic energy transfer studied by many-body Green's function theory.

We present a combination of many-body Green's function theory and Förster-Dexter theory to estimate the excitation energy transfer (EET) coupling in both the isolated and condensed systems. This approach employs the accurate wave functions of excitons, which are derived from the Bethe-Salpeter equation, in the donor and acceptor to set up the electronic coupling terms. Dexter coupling, which arises from the exchange-correlation effect, is evaluated based on the GW method which is a state-of-the-art ab initio theory for the description of self-energy. This approach is applicable to various situations, especially for periodic systems. The approach is tested on some model molecular dimers and compared with other high-level quantum chemistry methods together with the exact supermolecule scheme. Finally, we apply it to study the EET between periodic single-walled carbon nanotubes, exploring the dependence of EET on the chirality of nanotubes and the type of excitation transferred, finding that dark states play key roles in the EET between nanotubes. The EET rate falls as ∼D-12 approximately with the distance D between nanotubes for small D, much faster than the traditional Förster model.

Optical properties of acene molecules and pentacene crystal from the many-body Green's function method.

Acene is a type of important organic semiconductor which has promising applications in various optoelectronic devices. The fission of a singlet to triplet in it has been expected to elevate the quantum efficiency of organic solar cells. However, the quantum efficiency is still very low and the fission process is still under debate. Controversies also exist on the energies of the singlet and triplet states in acene. Using the many-body Green's function theory, which includes the GW method and Bethe-Salpeter equation (BSE), we compared the electronic excited states of several kinds of acene molecules (naphthalene to pentacene) at geometries optimized by different approaches. The energies of both the singlet and triplet depend strongly on the geometries of the molecules and their stacking. The non-negligible contribution from the resonant and anti-resonant transition coupling can cause large errors of the Tamm-Dancoff approximation, and the full BSE is required to get accurate results which are consistent with experiments. We found that accurate ionization energies and exciton energies can only be obtained when the geometries optimized by the Hartree-Fock approach are used. Singlet fission may be realized in isolated molecules, clusters, and surfaces, but it is hard in perfect pentacene crystals energetically. We provide a methodology for future research on acene-based solar cells and other optoelectronic devices.

Excitons and Davydov splitting in sexithiophene from first-principles many-body Green's function theory.

Organic semiconductors have promising and broad applications in optoelectronics. Understanding their electronic excited states is important to help us control their spectroscopic properties and performance of devices. There have been a large amount of experimental investigations on spectroscopies of organic semiconductors, but theoretical calculation from first principles on this respect is still limited. Here, we use density functional theory (DFT) and many-body Green's function theory, which includes the GW method and Bethe-Salpeter equation, to study the electronic excited-state properties and spectroscopies of one prototypical organic semiconductor, sexithiophene. The exciton energies of sexithiophene in both the gas and bulk crystalline phases are very sensitive to the exchange-correlation functionals used in DFT for ground-state structure relaxation. We investigated the influence of dynamical screening in the electron-hole interaction on exciton energies, which is found to be very pronounced for triplet excitons and has to be taken into account in first principles calculations. In the sexithiophene single crystal, the energy of the lowest triplet exciton is close to half the energy of the lowest singlet one. While lower-energy singlet and triplet excitons are intramolecular Frenkel excitons, higher-energy excitons are of intermolecular charge-transfer type. The calculated optical absorption spectra and Davydov splitting are in good agreement with experiments.

The charge-transfer states and excitation energy transfers of halogen-free organic molecules from first-principles many-body Green's function theory.

The organic solar cells based on halogen-free components, have been the new favorites to develop green and renewable energy. PBDB-T and its derivatives are considered the superior electron donors to construct the solar cells. Although there are plenty of researches about them, the charge-transfer mechanisms and excitation energy transfers of relative organic solar cells are still unclear, the developments of photovoltaic devices are restricted consequently. In this work, we calculate the electronic structures and excited-state properties of PBDB-T, PBT1-C, PBT1-O and PBT1-S donors in the gas phase from the many-body Green's function theory. With BTP-IC and BTP-IS as the acceptors, we consider the Förster, Dexter, and overlap electronic couplings to compute the excitation energy transfers of the dimers. The ionization energies and excited-state energies of the four donors calculated by GW + BSE are in good agreement with experiments, and they are sensitive to the functionals in the computation. We find two charge transfer schemes. The thienyl of PBDB-T molecule makes its charge-transfer state at the lowest energy, and the total electronic coupling of PBDB-T based dimer is the strongest. The Dexter, and overlap types electronic couplings are significant to study the excitation energy transfer of organic heterojunctions. We provide a theoretical guide in the design and synthesis of higher-performance halogen-free donors.

A preliminary evaluation of targeted nanopore sequencing technology for the detection of Mycobacterium tuberculosis in bronchoalveolar lavage fluid specimens.

Objective: To evaluate the efficacy of targeted nanopore sequencing technology for the detection of Mycobacterium tuberculosis(M.tb.) in bronchoalveolar lavage fluid(BALF) specimens. Methods: A prospective study was used to select 58 patients with suspected pulmonary tuberculosis(PTB) at Henan Chest Hospital from January to October 2022 for bronchoscopy, and BALF specimens were subjected to acid-fast bacilli(AFB) smear, Mycobacterium tuberculosis MGIT960 liquid culture, Gene Xpert MTB/RIF (Xpert MTB/RIF) and targeted nanopore sequencing (TNS) for the detection of M.tb., comparing the differences in the positive rates of the four methods for the detection of patients with different classifications. Results: Among 58 patients with suspected pulmonary tuberculosis, there were 48 patients with a final diagnosis of pulmonary tuberculosis. Using the clinical composite diagnosis as the reference gold standard, the sensitivity of AFB smear were 27.1% (95% CI: 15.3-41.8); for M.tb culture were 39.6% (95% CI: 25.8-54.7); for Xpert MTB/RIF were 56.2% (95% CI: 41.2-70.5); for TNS were 89.6% (95% CI: 77.3-96.5). Using BALF specimens Xpert MTB/RIF and/or M.tb. culture as the reference standard, TNS showed 100% (30/30) sensitivity. The sensitivity of NGS for pulmonary tuberculosis diagnosis was significantly higher than Xpert MTB/RIF, M.tb. culture, and AFB smear. Besides, P values of <0.05 were considered statistically significant. Conclusion: Using a clinical composite reference standard as a reference gold standard, TNS has the highest sensitivity and consistency with clinical diagnosis, and can rapidly and efficiently detect PTB in BALF specimens, which can aid to improve the early diagnosis of suspected tuberculosis patients.

Surface PEGylated Cancer Cell Membrane-Coated Nanoparticles for Codelivery of Curcumin and Doxorubicin for the Treatment of Multidrug Resistant Esophageal Carcinoma.

OBJECTIVE: The emergence of multi-drug resistance (MDR) in esophageal carcinoma has severely affected the effect of chemotherapy and shortened the survival of patients. To this end, we intend to develop a biomimetic nano-targeting drug modified by cancer cell membrane, and investigate its therapeutic effect. METHODS: The degradable poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) co-loaded with doxorubicin (DOX) and curcumin (Cur) were prepared by solvent evaporation method. TE10 cell membrane and Distearoyl phosphatidylethanolamine-polyethylene glycol (DSPE-PEG) were then coated on the PLGA NPs by membrane extrusion to prepare the PEG-TE10@PLGA@DOX-Cur NPs (PMPNs). Size and zeta potential of the PMPNs were analyzed by lazer particle analyzer, and the morphology of PMPNs was observed by transmission electron microscope. The TE10 cell membrane protein on PMPNs was analyzed by gel electrophoresis. The DOX-resistant esophageal cancer cell model TE10/DOX was established through high-dose induction. The In vitro homologous targeting ability of PMPNs was evaluated by cell uptake assay, and the in vitro anti-tumor effect of PMPNs was assessed through CCK-8, clone formation and flow cytometry. A Balb/c mouse model of TE10/DOX xenograft was constructed to evaluate the anti-tumor effect in vivo and the bio-safety of PMPNs. RESULTS: The prepared cell membrane coated PMPNs had a regular spherical structure with an average diameter of 177 nm. PMPNs could directly target TE10 and TE10/DOX cells or TE10/DOX xenografted tumor and effectively inhibit the growth of DOX-resistant esophageal carcinoma. Besides, the PMPNs was confirmed to have high biosafety. CONCLUSION: In this study, a targeted biomimetic nano-drug delivery system PMPNs was successfully prepared, which overcome the MDR of esophageal carcinoma by co-delivering DOX and sensitizer curcumin.

A new energy transfer channel from carotenoids to chlorophylls in purple bacteria.

It is unclear whether there is an intermediate dark state between the S2 and S1 states of carotenoids. Previous two-dimensional electronic spectroscopy measurements support its existence and its involvement in the energy transfer from carotenoids to chlorophylls, but there is still considerable debate on the origin of this dark state and how it regulates the energy transfer process. Here we use ab initio calculations on excited-state dynamics and simulated two-dimensional electronic spectrum of carotenoids from purple bacteria to provide evidence supporting that the dark state may be assigned to a new Ag+ state. Our calculations also indicate that groups on the conjugation backbone of carotenoids may substantially affect the excited-state levels and the energy transfer process. These results contribute to a better understanding of carotenoid excited states.Carotenoids harvest energy from light and transfer it to chlorophylls during photosynthesis. Here, Feng et al. perform ab initio calculations on excited-state dynamics and simulated 2D electronic spectrum of carotenoids, supporting the existence of a new excited state in carotenoids.