Functional analysis of ecdysteroid biosynthetic enzymes of the rice planthopper, Nilaparvata lugens.

Ecdysteroids, insect steroid hormones, play key roles in regulating insect development and reproduction. Hemipteran insects require ecdysteroids for egg production; however, ecdysteroid synthesis (ecdysteroidogenesis) details have not been elucidated. We identified all known genes encoding ecdysteroidogenic enzymes in Nilaparvata lugens and clarified their necessity during nymphal and ovarian development.

Molecular dynamics simulation, ab initio calculation, and size-selected anion photoelectron spectroscopy study of initial hydration processes of calcium chloride.

To understand the initial hydration processes of CaCl, we performed molecular simulations employing the force field based on the theory of electronic continuum correction with rescaling. Integrated tempering sampling molecular dynamics were combined with ab initio calculations to overcome the sampling challenge in cluster structure search and refinement. The calculated vertical detachment energies of CaCl(HO) (n = 0-8) were compared with the values obtained from photoelectron spectra, and consistency was found between the experiment and computation.

Initial hydration processes of magnesium chloride: size-selected anion photoelectron spectroscopy and ab initio calculations.

To understand the initial hydration processes of MgCl, we measured photoelectron spectra of MgCl(HO) (n = 0-6) and conducted ab initio calculations on MgCl(HO) and their neutral counterparts up to n = 7. A dramatic drop in the vertical detachment energy (VDE) was observed upon addition of the first water molecule to bare MgCl. This large variation in VDE can be associated with the charge-transfer-to-solvent (CTTS) effect occurring in the MgCl(HO) clusters, as hydration induces transfer of the excess electron of MgCl to the water molecules.

Mucin-like protein, a saliva component involved in brown planthopper virulence and host adaptation.

The rice brown planthopper (BPH), Nilaparvata lugens, can rapidly adapt to new resistant rice varieties within several generations, rendering its management burdensome. However, the molecular mechanism underlying its adaptability remains unclear. In this study, we investigated the potential role of mucin-like protein (NlMul) in N.

A mitochondrial membrane protein is a target for rice ragged stunt virus in its insect vector.

Rice ragged stunt virus (RRSV; Reoviridae) is exclusively transmitted by the brown planthopper Nilaparvata lugens in a persistent-propagative manner. It is understood that RNA viral proliferation is associated with the intracellular membranes of the insect host cells. However, the molecular mechanisms of the interaction between the RRSV proliferation and the intracellular membranes remain essentially unknown.

Emergence of Solvent-Separated Na-Cl Ion Pair in Salt Water: Photoelectron Spectroscopy and Theoretical Calculations.

Solvation of salts in water is a fundamental physical chemical process, but the underlying mechanism remains unclear. We investigated the contact ion pair (CIP) to solvent-separated ion pair (SSIP) transition in NaCl(HO) clusters with anion photoelectron spectroscopy and ab initio calculations. It is found that the SSIP type of structures show up at n = 2 for NaCl(HO) anions.

Screening and Functional Analyses of Nilaparvata lugens Salivary Proteome.

Most phloem-feeding insects secrete gelling and watery saliva during the feeding process. However, the functions of salivary proteins are poorly understood. In this study, our purpose was to reveal the components and functions of saliva in a rice sap-sucking insect pest, Nilaparvata lugens.

Initial hydration behavior of sodium iodide dimer: photoelectron spectroscopy and ab initio calculations.

We investigated (NaI)2(-)(H2O)n (n = 0-6) clusters to examine the initial solvation process of (NaI)2 in water, using negative ion photoelectron spectroscopy and theoretical calculations. The structures of these clusters and their neutrals were determined by comparing ab initio calculations with experimental results. It is found that bare (NaI)2(-) is a L-shaped structure and the corresponding neutral is a rhombus.

A salivary sheath protein essential for the interaction of the brown planthopper with rice plants.

Salivary secretions, including gel saliva and watery saliva, play crucial roles in the interaction between the insect and plant during feeding. In this study, we identified a salivary gland-specific gene encoding a salivary sheath protein (NlShp) in Nilaparvata lugens. NlShp has two alternative splicing variants; both are expressed at high levels during the nymph and adult stages.

From thermodynamics to kinetics: enhanced sampling of rare events.

Despite great advances in molecular dynamics simulations, there remain large gaps between the simulations and experimental observations in terms of the time and length scales that can be approached. Developing fast and accurate algorithms and methods is of ultimate importance to bridge these gaps. In this Account, we briefly summarize recent efforts in such directions.

Photoelectron spectroscopy and ab initio calculations of Li(H₂O)n(-) and Cs(H₂O)n(-) (n = 1-6) clusters.

The Li(H2O)n(-) and Cs(H2O)n(-) (n = 0-6) clusters were studied using anion photoelectron spectroscopy combined with ab initio calculations. It was found that Li tends to be surrounded by water molecules with no water-water H-bonds being formed in the first hydration shell; while Cs sticks on the surface of water-water H-bonds network. The Li atom in its anionic or neutral state is surrounded by four water molecules through Li-O interactions within the first hydration shell; while the case of Cs is different.

Stable salt-water cluster structures reflect the delicate competition between ion-water and water-water interactions.

How salts affect water structure is an important topic in many research fields. Salt-water clusters can be used as model systems to extract interaction information that is difficult to obtain directly from bulk solutions. In the present study, integrated tempering sampling molecular dynamics (MD) are combined with quantum mechanics (QM) calculations to overcome the sampling problem in cluster structure searches.

Microsolvation of LiI and CsI in water: anion photoelectron spectroscopy and ab initio calculations.

In order to understand the microsolvation of LiI and CsI in water and provide information about the dependence of solvation processes on different ions, we investigated the LiI(H2O)n(-) and CsI(H2O)n(-) (n = 0-6) clusters using photoelectron spectroscopy. The structures of these clusters and their corresponding neutrals were investigated with ab initio calculations and confirmed by comparing with the photoelectron spectroscopy experiments. Our studies show that the structural evolutions of LiI(H2O)n and CsI(H2O)n clusters are very different.

Inhibitory mechanism of caspase-6 phosphorylation revealed by crystal structures, molecular dynamics simulations, and biochemical assays.

The apoptotic effector caspase-6 (CASP6) has been clearly identified as a drug target due to its strong association with neurodegeneration and axonal pruning events as well as its crucial roles in Huntington disease and Alzheimer disease. CASP6 activity is suppressed by ARK5-mediated phosphorylation at Ser(257) with an unclear mechanism. In this work, we solved crystal structures of ΔproCASP6S257E and p20/p10S257E, which mimicked the phosphorylated CASP6 zymogen and activated CASP6, respectively.

Induced endothelial cells enhance osteogenesis and vascularization of mesenchymal stem cells.

Adequate vascularization remains one of the major challenges in bone tissue engineering. Since the microvascular endothelium is of benefit to osteogenesis and vascularization when in direct contact with bone marrow mesenchymal stem cells (BM-MSCs), we investigated whether endothelial cells induced from BM-MSCs have the same effect on BM-MSCs in vitro and in vivo. BM-MSCs were isolated, characterized and induced into endothelial-like cells (induced endothelial cells, IECs) in endothelial cell growth medium 2.

[Prokaryotic expression, purification and refolding of extracellular ligand binding domains of chick Tie-2 and its immunogenicity].

Objective: To study the prokaryotic expression of extracellular ligand binding domains of chick Tie-2, the purification and refolding conditions of the recombinant protein, and to observe its immunogenicity in mouse.

Methods: A DNA fragment encoding extracellular ligand binding domains of chick Tie-2 was obtained by PCR from a previous constructed plasmid as a template. The amplified fragment was then inserted into prokaryotic expression vector PQE30, and was expressed in E.

Molecular cloning and tissue-specific, developmental-stage-specific, and hormonal regulation of IGFBP3 gene in zebrafish.

The biological functions of insulin-like growth factor (IGF) I and II are modulated by a family of IGF-binding proteins (IGFBPs) in complex IGF-dependent and IGF-independent pathways. For further understanding of the actions of IGFs, some of these binding proteins have been cloned and characterized. We report the molecular cloning of IGFBP-3 cDNA for zebrafish.

The carp muscle-specific sub-isoenzymes of creatine kinase form distinct dimers at different temperatures.

We have previously cloned three muscle-specific sub-isoforms of creatine kinase (CK, EC 2.7.3.