Molecular processes in iron and zinc homeostasis and their modulation for biofortification in rice

More than a billion people suffer from iron or zinc deficiencies globally. Rice(Oryza sativa L.) iron and zinc biofortification; i.e., intrinsic iron and zinc enrichment of rice grains, is considered the most effective way to tackle these deficiencies. However, rice iron biofortification, by means of conventional breeding, proves difficult due to lack of sufficient genetic variation. Meanwhile,genetic engineering has led to a significant increase in the iron concentration along with zinc concentration in rice grains. The design of impactful genetic engineering biofortification strategies relies upon vast scientific knowledge of precise functions of different genes involved in iron and zinc uptake, translocation and storage. In this review, we present an overview of molecular processes controlling iron and zinc homeostasis in rice. Further,the genetic engineering approaches adopted so far to increase the iron and zinc concentrations in polished rice grains are discussed in detail, highlighting the limitations and/or success of individual strategies. Recent insight suggests that a few genetic engineering strategies are commonly utilized for elevating iron and zinc concentrations in different genetic backgrounds, and thus, it is of great importance to accumulate scientific evidence for diverse genetic engineering strategies to expand the pool of options for biofortifying farmer-preferred cultivars.

Molecular Clump Extraction Algorithm Based on Local Density Clustering

The detection and parameterization of molecular clumps are the first step in studying them.We propose a method based on the Local Density Clustering algorithm while physical parameters of those clumps are measured using the Multiple Gaussian Model algorithm.One advantage of applying the Local Density Clustering to the clump detection and segmentation,is the high accuracy under different signal-to-noise levels.The Multiple Gaussian Model is able to deal with overlapping clumps whose parameters can reliably be derived.Using simulation and synthetic data,we have verified that the proposed algorithm could accurately characterize the morphology and flux of molecular clumps.The total flux recovery rate in 13CO(J=1-0)line of M16 is measured as 90.2%.The detection rate and the completeness limit are 81.7%and 20 K km s-1 in 13CO(J=1-0)line of M16,respectively.

Charge transfer and excitation processes in low energy collisions of He ions with Li atoms

Electron capture between solar wind ions and neutral species has contributed to the understanding of X-ray production from solar system bodies.The charge transfer and excitation processes in solar wind ions of He^(+)(1 s) colliding with Li(1 s^(2)2 s) atoms are studied by utilizing the full quantum-mechanical molecular-orbital close-coupling(QMOCC) method with impact energies of 0.003-2 keV amu-1.Comparisons of cross sections from single-and multi-configurational calculations for a selfconsistent field(SCF and MCSCF) process are carried out.Results show that the dominant reaction channels are He(1 s2 l ^(1,3) L)+Li^(+)(1 s^(2) ^(1) S).Good consistency is found among present total and state-selective charge transfer and excitation cross sections with other theoretical and experimental data in the same energy region.Due to the differences between coupling matrix elements in high-energy states,the charge transfer cross sections calculated from SCF and MCSCF split slightly as E> 0.4 keV amu-1.Weak Stueckelberg oscillations for charge transfer appear in the present work.In addition,the differences of cross sections for electron excitation to Li(ls^(2)2 p) in the singlet/triplet molecular states with He+(1 s) are much smaller than those of charge transfer processes because of the similar energy gaps from Li(ls^(2)2 p) to the ground state in singlet/triplet states in the large R region.

Using vibrational infrared biomolecular spectroscopy to detect heat-induced changes of molecular structure in relation to nutrient availability of prairie whole oat grains on a molecular basis

Background： To our knowledge, there is little study on the interaction between nutrient availability and molecular structure changes induced by different processing methods in dairy cattle. The objective of this study was to investigate the effect of heat processing methods on interaction between nutrient availability and molecular structure in terms of functional groups that are related to protein and starch inherent structure of oat grains with two continued years and three replication of each year.Method： The oat grains were kept as raw（control） or heated in an air-draft oven（dry roasting： DO） at 120 °C for 60 min and under microwave irradiation（MIO） for 6 min. The molecular structure features were revealed by vibrational infrared molecular spectroscopy.Results： The results showed that rumen degradability of dry matter, protein and starch was significantly lower（P 〈0.05） for MIO compared to control and DO treatments. A higher protein α-helix to β-sheet and a lower amide I to starch area ratio were observed for MIO compared to DO and/or raw treatment. A negative correlation（-0.99, P 〈 0.01）was observed between α-helix or amide I to starch area ratio and dry matter. A positive correlation（0.99, P 〈 0.01） was found between protein β-sheet and crude protein.Conclusion： The results reveal that oat grains are more sensitive to microwave irradiation than dry heating in terms of protein and starch molecular profile and nutrient availability in ruminants.

Mapping of Compositional Diversity and Chronological Ages of Lunar Farside Multiring Mare Moscoviense Basin:Implications to the Middle Imbrian Mare Basalts

The Mare Moscoviense is an astonishing rare flatland multi-ring basin and one of the recognizable mare regions on the Moon's farside.The mineralogical,chronological,topographical and morphological studies of the maria surface of the Moon provide a primary understanding of the origin and evolution of the mare provinces.In this study,the Chandrayaan-1 M^(3)data have been employed to prepare optical maturity index,FeO and TiO^(2)concentration,and standard band ratio map to detect the mafic indexes like olivine and pyroxene minerals.The crater size frequency distribution method has been applied to LROC WAC data to obtain the absolute model ages of the Moscoviense basin.The four geological unit ages were observed as 3.57 Ga(U-2),3.65 Ga(U-1),3.8 Ga(U-3)and 3.92 Ga(U-4),which could have been formed between the Imbrian and Nectarian epochs.The M^(3)imaging and reflectance spectral parameters were used to reveal the minerals like pyroxene,olivine,ilmenite,plagioclase,orthopyroxene-olivine-spinel lithology,and olivine-pyroxene mixtures present in the gabbroic basalt,anorthositic and massive ilmenite rocks,and validated with the existing database.The results show that the Moscoviense basin is dominated by intermediate TiO^(2)basalts that derived from olivine-ilmenite-pyroxene cumulate depths ranging from 200 to 500 km between 3.5 Ga and 3.6 Ga.

Volatile Depletion in Planet-Forming Disks

Newly born stars are surrounded by gas and dust with a attened axisymmetric distribution termed protoplanetary disk,in which planets are formed.Observations of these objects are necessary for understanding the formation and early evolution of stars and planets,and for revealing the composition of the raw material from which planets are made.Numerical models can extract important parameters from the observational data,including the gas and dust mass of the disk.These parameters are used as input for further modeling,e.g.,to calculate the chemical composition of the disk.A consistent thermochemical model should be able to reproduce the abundances of di erent species in the disk.However,this good wish has been challenged for many disks:models over-predict the emission line intensity of some species;namely,they are depleted(with respect to expectations from canonical models).In this review we show how this disparity indicates that dust evolution has signi cant e ects on gas chemistry,and may indicate the earliest stages of planet formation.

Methanol formation chemistry with revised reactions scheme

The aim of the presented work is to analyze the impact of experimentally evaluated reactions of hydrogen abstraction on surfaces of interstellar grains on the chemical evolution of methanol and its precursors on grains and in the gas phase under conditions of a cold dark cloud and during the collapse of a translucent cloud into a dark cloud. Analysis of simulation results shows that those reactions are highly efficient destruction channels for HCO and H2CO on grain surfaces, and significantly impact the abundances of almost all molecules participating in the formation of CH3OH. Next, in models with those reactions, maximum abundances of methanol in gas and on grain surfaces decrease by more than 2–3 orders of magnitude in comparison to models without surface abstraction reactions of hydrogen. Finally, we study the impact of binding energies of CH2OH and CH3O radicals on methanol chemistry.

Laboratory study of the formation of fullerene(from smaller to larger, C44 to C70)/anthracene cluster cations in the gas phase

The formation and evolution mechanism of fullerenes in the planetary nebula or in the interstellar medium are still not understood.Here,we present the study on the cluster formation and the relative reactivity of fullerene cations(from smaller to larger,C44 to C70) with anthracene molecule(C14H10).The experiment is performed in an apparatus that combines a quadrupole ion trap with a time-of-flight mass spectrometer.By using a 355 nm laser beam to irradiate the trapped fullerenes cations(C60+or C70+),smaller fullerene cations C(60-2 n)+, n=1-8 or C(70-2 m)+,m=1-11 are generated,respectively.Then reacting with anthracene molecules,series of fullerene/anthracene cluster cations are newly formed(e.g.,(C14H10)C(60-2 n)+,n=1-8 and(C14H10)C(70-2 m)+,m=1-11),and slight difference of the reactivity within the smaller fullerene cations are observed.Nevertheless,smaller fullerenes show obviously higher reactivity when comparing to fullerene C60+ and C70+.A successive loss of C2 fragments mechanism is suggested to account for the formation of smaller fullerene cations,which then undergo addition reaction with anthracene molecules to form the fullerene-anthracene cluster cations.It is found that the higher laser energy and longer irradiation time are key factors that affect the formation of smaller fullerene cations.This may indicate that in the strong radiation field environment(such as photon-dominated regions) in space,fullerenes are expected to follow the top-down evolution route,and then form small grain dust(e.g.,clusters) through collision reaction with co-existing molecules,here,smaller PAHs.

A new data structure for accelerating kinetic Monte Carlo method

The kinetic Monte Carlo simulation is a rigorous numerical approach to study the chemistry on dust grains in cold dense interstellar clouds. By tracking every single reaction in chemical networks step by step, this approach produces more precise results than other approaches but takes too much computing time. Here we present a method of a new data structure, which is applicable to any physical conditions and chemical networks, to save computing time for the Monte Carlo algorithm. Using the improved structure,the calculating time is reduced by 80 percent compared with the linear structure when applied to the osu-2008 chemical network at 10K. We investigate the effect of the encounter desorption in cold cores using the kinetic Monte Carlo model with an accelerating data structure. We found that the encounter desorption remarkably decreases the abundance of grain-surface H2 but slightly influences the abundances of other species on the grain.

Depolarizing isotropic collisions of the CN solar molecule with electrons

Existence of linear polarization,formed by anisotropic scattering in the photosphere,has been demonstrated observationally as well as theoretically and is called second solar spectrum(SSS).The SSS is distinguished by its structure,which is rich in terms of information.In order to analyze the SSS,it is necessary to evaluate the(de)polarizing effect of isotropic collisions between CN solar molecules and electrons or neutral hydrogen atoms.This work is dedicated to calculations of the polarization transfer rates associated with CN-electron isotropic collisions.We show that usual rates serve as a proxy for polarization transfer rates.Then,we take advantage of available usual excitation collisional rates obtained via sophisticated quantum methods in order to derive the polarization transfer rates for the X^2Σ+-B^2Σ+(violet) and X^2Σ+-A^2Π(red) systems of CN.Our approach is based on the infinite order sudden(IOS)approximation and can be applied for other solar molecules.We discuss the effectiveness of collisions with electrons on the SSS of the CN lines.Our results contribute to reducing the degree of complication in modeling the formation of the SSS of CN.

Millimeter observations of organic molecules toward high-mass star formation region G34.26+0.15

To investigate the chemical origination of organic molecules CH3OH, CH3OCH3, C2H5OH, CH3OCH, CH3CN, C2HaCN and C2H5CN in the hot core associated with high-mass star formation re- gion G34.26＋0.15, Submillimeter Array observations were made with its 230 GHz receiver. The molecular gas distribution has shown that the oxygen- and nitrogen-containing molecules peak at different positions. Comparing the spatial distributions with rotational temperatures and fractional abundances of the observed molecules, we discuss the possible chemical origination of these organic molecules.

Investigating Sulfur Chemistry in the HD163296 Disk

Sulfur chemistry in the formation process of low-mass stars and planets remains poorly understood.The protoplanetary disks are the birthplace of planets and its distinctive environment provides an intriguing platform for investigating models of sulfur chemistry.We analyzed the Atacama Large Millimeter/submillimeter Array observations of CS 7-6 transitions in the HD 163296 disk and performed astrochemical modeling to explore its sulfur chemistry.We simulated the distribution of sulfur-containing molecules and compared it with observationally deduced fractional column densities.We have found that the simulated column density of CS is consistent with the observationally deduced fractional column densities,while the simulated column density of C_2S is lower than the observationally deduced upper limits on column densities.This results indicate that we have a good understanding of the chemical properties of CS and C_2S in the disk.We also investigated the influence of the C/O ratio on sulfur-containing molecules and found that the column densities of SO,SO_2,and H_2S near the centra star are dependent on the C/O ratio.Additionally,we found that the N[CS]/N[SO]ratio can serve as a promising indicator of the disk’s C/O ratio in HD 163296.Overall,the disk of HD 163296 provides a favorable environmen for the detection of sulfur-containing molecules.

Source dynamics of carbonaceous aerosol during the haze bloom-decay process in China based on radiocarbon and organic molecular tracer

With the support by the National Natural Science Foundation of China and the Chinese Academy of Sciences,the research team led by Prof.Li Jun(李军)at the State Key Laboratory of Organic Geochemistry,Guangzhou Institute of Geochemistry,Chinese Academy of Sciences,illustrated the source dynamics of carbonaceous aerosol during the haze bloom-decay process in Beijing and Guangzhou based on