Taxonomic revision of the genus Jassidophaga Aczél (Diptera: Pipunculidae) in Korea

In this paper, three Korean species of the big‐head fly, genus Jassidophaga Aczél were treated: J. chiiensis (Ouchi), J. pala (Morakote) and J. villosa (Roser). Of these, J. pala is reported in Korea for the first time. A key to Korean species and photographs on external features are given.     

Exosomal ANXA2 derived from ovarian cancer cells regulates epithelial-mesenchymal plasticity of human peritoneal mesothelial cells

Ovarian cancer, one of the malignant gynaecological tumours with the highest mortality rate among female reproductive system, is prone to metastasis, recurrence and chemotherapy resistance, causing a poor prognosis. Exosomes can regulate the epithelial-mesenchymal plasticity of tumour cells, remodel surrounding tumour microenvironment, and affect tumour cell proliferation, invasion and metastasis. However, the function and mechanism of exosomes in the intraperitoneal implantation of ovarian cancer remain unclear. In this study, exosomal annexin A2 (ANXA2) derived from ovarian cancer cells was co-cultured with human peritoneal mesothelial (HMrSV5) cells; functional experiments were conducted to explore the effects of exosomal ANXA2 on the biological behaviour of HMrSV5 and the related mechanisms. This study showed that ANXA2 in ovarian cancer cells can be transferred to HMrSV5 cells through exosomes, exosomal ANXA2 can not only promote the migration, invasion and apoptosis of HMrSV5 cells, but also regulates morphological changes and fibrosis of HMrSV5 cells. Furthermore, ANXA2 promotes the mesothelial-mesenchymal transition (MMT) and degradation of the extracellular matrix of HMrSV5 cells through PI3K/AKT/mTOR pathway, finally affects pre-metastasis microenvironment of ovarian cancer, which provides a new theoretical basis for the mechanism of intraperitoneal implantation and metastasis of ovarian cancer.     

Molecular Dynamics Simulation Studies of Zeolite-A. IV. Structure and Dynamics of NH4 + ions in a Rigid Dehydrated Zeolite-A

Abstract

In recent papers [1–3] we reported molecular dynamics simulation studies of ions and water molecules adsorbed in a rigid zeolite-A framework using a simple Lennard-Jones potential plus Coulomb potential with Ewald summation to investigate the structure and dynamics of the adsorbates. In the present paper the same technique is applied to study the local structure and dynamics of NH₄ ⁺ ions in a rigid dehydrated zeolite-A. During the preliminary equilibration, the unstable NH₄(4) type ion (the 12th ion) is pushed down to near a more stable 6-ring position in the α-cage that is already associated with an NH₄(1) type ion (the 1st) in the β-cage, which moves to another 6-ring position in the β-cage that is already associated with an NH₄(2) type ion (the 7th) in the α-cage. Calculated x, y, and z coordinates of some NH₄ ⁺ ions are in good agreement with those obtained from an X-ray diffraction experiment except that no NH₄(4) type ion is found and there are six NH₄(2) type ions instead of 0.5 and 5.5 occupancy. The analyses of calculated interatomic distances and time correlation functions of these ions indicate that the NH₄(1 – 1) and NH₄(3) type ions are associated loosely with only one O (3) atom of the 6-ring and with only one O (1) atom of the 8-ring windows, respectively, while the NH₄(1–2) and NH₄(2) type ions are associated strongly with two or three O (3) atoms of the 6-ring windows in the α- and β-cages, respectively. The analysis of hydrogen bond time correlation functions of these ions indicate that about one, two or three, three, and one hydrogen bond of each NH₄(1–1), NH₄(1–2), NH₄(2) and NH₄(3) type ion is kept for 1.4, 21, 75, and 1.4 ps, respectively, before breakup of the hydrogen bond occurs and significant exchange of O atom hydrogen-bonded to the ion.     

N-Phenyl-4-hydroxy-2-quinolone-3-carboxamides as selective inhibitors of mutant H1047R phosphoinositide-3-kinase (PI3Kα)

This work describes our efforts to optimize the lead PI3Kα inhibitor N-benzyl 4-hydroxy-2-quinolone-3-carboxamide using structure-based design and molecular docking. We identified a series of N-phenyl 4-hydroxy-2-quinolone-3-carboxamides as selective inhibitors of mutant H1047R versus wild-type PI3Kα and we also showed that the cell growth inhibition by these compounds likely occurs by inhibiting the formation of pAKT and induction of apoptosis.     

External Noise and External Signal Induced Transition of Gene Switch and Coherence Resonance in the Genetic Regulatory System

The transition of gene switch induced by external noises (multiplicative external noise and additive external noise) and external signals is investigated in the genetic regulatory system. Results show that the state-to-state transition of gene switch as well as resonant behaviors, such as the explicit coherence resonance (ECR), implicit coherence resonance (ICR) and control parameter coherence biresonance (CPCBR), can appear when noises are injected into the genetic regulatory system. The ECR is increased with the increase of the control parameter value when starting from the supercritical Hopf bifurcation parameter point, and there exists a critical control parameter value for the occurrence of ECR. However, the ICR is decreased as the control parameter value is increased when starting from the subcritical Hopf bifurcation point. In particular, the coherence of ECR is higher and more sensitive to noise than that of ICR. When an external signal is introduced into the system, the enhancement or suppression of the CPCBR and the number of peaks strongly depend on the frequency and amplitude of the external signal. Furthermore, the gene regulation system can selectively enhance or decrease the noise-induced oscillation signals at preferred frequency and amplitude of an external signal.     

Multiple species of wild tree peonies gave rise to the ‘king of flowers’, Paeonia suffruticosa Andrews

The origin of cultivated tree peonies, known as the ‘king of flowers'' in China for more than 1000 years, has attracted considerable interest, but remained unsolved. Here, we conducted phylogenetic analyses of explicitly sampled traditional cultivars of tree peonies and all wild species from the shrubby section Moutan of the genus Paeonia based on sequences of 14 fast-evolved chloroplast regions and 25 presumably single-copy nuclear markers identified from RNA-seq data. The phylogeny of the wild species inferred from the nuclear markers was fully resolved and largely congruent with morphology and classification. The incongruence between the nuclear and chloroplast trees suggested that there had been gene flow between the wild species. The comparison of nuclear and chloroplast phylogenies including cultivars showed that the cultivated tree peonies originated from homoploid hybridization among five wild species. Since the origin, thousands of cultivated varieties have spread worldwide, whereas four parental species are currently endangered or on the verge of extinction. The documentation of extensive homoploid hybridization involved in tree peony domestication provides new insights into the mechanisms underlying the origins of garden ornamentals and the way of preserving natural genetic resources through domestication.