Genetic loci mapping for ear axis weight using recombinant inbred line (RIL) population under different nitrogen regimes in maize

Ear axis weight (EAW) is one of the important agronomic traits in maize (Zea mays L.), related to yield. To understand its genetic basis, a recombinant inbred line (RIL) population, derived from the cross Mo17 × Huangzao4, was used for quantitative trait locus mapping (QTL) for EAW under high and low nitrogen (N) regimes. The results showed that a total of three QTLs were mapped on chromosomes 2 (two) and 4 (one) under the two N regimes, which could explain phenotypic variances from 4.76 to 7.12%. They were near to their linked markers, with mapping interval of 0.2 to 1.0 cM. The two loci on chromosome 2 (bin 2.09) made EAW increase due to positive additive effects, while the other locus on chromosome 4 (bin 4.08) made EAW decrease to some extent, owing to negative additive effects. These results are beneficial for understanding the genetic basis of KNE and developing marker-assisted selection in maize breeding project.Key words: Maize (Zea mays L.), ear axis weight, quantitative trait locus, recombinant inbred line, nitrogen

A quantitative trait locus for the number of days from sowing to seedling emergence in maize

Quantitative trait locus (QTL) mapping provides useful information for breeding programs since it allows the estimation of genomic locations and genetic effects of chromosomal regions related to the expression of quantitative traits. The number of days from sowing to seedling emergence (NDSSE) is an important agronomic trait in a maize (Zea mays L.) breeding project which is related to yield. To determine its genetic basis, a recombinant inbred line (RIL) population and two nitrogen (N) regimes were used to detect the QTLs associated with NDSSE; as a result, one QTL was identified under high N regime, on chromosome 9, which could explain 6.20% of phenotypic variance and a decrease of 0.18 of NDSSE due to an additive effect. These results are beneficial for understanding the genetic basis of NDSSE in maize breeding project.Key words: Maize (Zea mays L.), quantitative trait locus, recombinant inbred line, nitrogen

Cassiterite oxygen isotopes in magmatic-hydrothermal systems: in situ microanalysis, fractionation factor, and applications

Tin and tungsten are important metals for the industrializing society. Deciphering the origin and evolution of hydrothermal fluids responsible for their formation is critical to underpin genetic models of ore formation. Traditional approaches obtain isotopic information mainly from bulk analysis of both ore and gangue minerals, or less frequently from in situ analysis of gangue minerals, which either bear inherited complexities and uncertainties or are indirect constraints. Hence, directly obtaining isotopic information from ore minerals such as cassiterite by in situ techniques is warranted. However, this has been hampered by challenges from both analytical and applicational aspects. In this study, we first demonstrate a lack of crystallographic orientation effects during cassiterite ion microprobe oxygen isotope analysis. Along with our newly developed matrix-matched reference material, the Yongde-Cst, which has a recommended δ18O value of 1.36 ± 0.16‰ (VSMOW) as defined by gas source isotope ratio mass spectrometry, in situ oxygen isotope analysis of cassiterite now is possible. We further refine the oxygen isotope fractionation (1000 ln α) for quartz-cassiterite by first-principles calculations, which is given by the equation of 1.259 × 106/T2 + 8.15 × 103/T − 4.72 (T is temperature in Kelvin). The 1000 ln α for quartz-cassiterite has a sensitive response to temperature, and makes cassiterite-quartz an excellent mineral pair in oxygen isotope thermometry, as described by the equation of T (℃) = 2427 × (δ18Oqtz − δ18Ocst)−0.4326 − 492.4. Using the well-established 1000 ln α of quartz-water, 1000 ln α of cassiterite-water is derived as 2.941 × 106/T2 − 11.45 × 103/T + 4.72 (T in Kelvin), which shows a weak response to temperature. This makes cassiterite an ideal mineral from which to derive δ18O of fluids as robust temperature estimates are no longer a prerequisite. We have applied oxygen isotope analysis to cassiterite samples from six Sn(-W) deposits in China. The results show considerable variability in δ18O values both within a single deposit and among studied deposits. Combining the δ18O of cassiterite samples and the equilibrium oxygen isotope fractionation, we find that the δ18O values of ore-forming fluids show a strong magmatic affinity with variable but mostly no to low degree involvements (~0-10%) of meteoric water, hence our results invite a reassessment on the extent and role of meteoric water in Sn-W mineralization. This study demonstrates that in situ oxygen isotope analysis of cassiterite is a promising tool to refine sources of ore-forming fluids, and to decode hydrothermal dynamics controlling tin and tungsten mineralization

Molecular Cloning, Characterization, and Expression Analysis of an Estrogen Receptor-Related Receptor Homologue in the Cricket, Teleogryllus emma

The estrogen receptor-related receptors (ERRs) are a group of nuclear receptors that were originally identified on the basis of sequence similarity to estrogen receptors. The three mammalian ERR genes have been implicated in diverse physiological processes ranging from placental development to maintenance of bone density, but the function and regulation of ERRs in invertebrates are not well understood. A homologue of human ERR was isolated from the cricket Teleogryllus emma (Ohmachi and Matsumura) (Orthoptera: Gryllidae). The full-length cDNA of T. emma ERR, termed TeERR, has 1618 base pair (bp) and contains a 5′?-untranslated region of 140 bp and a 3′?-untranslated region of 272 bp. The open reading frame of TeERR encodes a deduced 401 amino acid peptide with a predicted molecular mass of 45.75 kilodaltons. The results of sequence alignments indicate that the TeERR protein shares an overall identity of 65%–82% with other known ERR homologues, and is most closely related to that of Nasonia vitripennis (Hymenoptera: Pteromalidae) and Apis mellifera (Apidae). Real-time quantitative reverse transcription-polymerase chain reaction was performed to compare the TeERR mRNA expression level at the whole body and gonad during T. emma development. The data revealed that TeERR mRNA is differentially expressed during T. emma development, with the highest expression level in embryos and the lowest in the body of late-instar larvae. The levels of TeERR transcripts also varied throughout gonad development; interestingly testicles had higher higher expression levels than ovaries at every development stage. These results suggest that TeERR has potential significance in the regulation of development in T. emma, due to its expression during different developmental periods

Seroprevalence of Mycoplasma bovis infection in dairy cows in subtropical southern China

The seroprevalence of Mycoplasma bovis infection in dairy cows in Guangxi Zhuang Autonomous Region (GZAR) in subtropical southern China was surveyed between June 2009 and March 2010. A total of 455 serum samples of dairy cows were collected from 6 districts in 4 different cities, and examined for M. bovis antibodies with the indirect enzyme-linked immunosorbent assay (ELISA) using a commercially available kit. The overall seroprevalence of M. bovis infection in dairy cows was 7.69% (35/455). Three year-old dairy cows had the highest seroprevalence (15.0%), followed by dairy cows of 4 year-old (11.1%). Dairy cows with the history of 5 pregnancies had the highest seroprevalence (33.3%). However, no statistically significant association was found between M. bovis infection and age or number of pregnancies (p > 0.05). All the aborting dairy cows were negative for M. bovis antibodies, suggesting that bovine abortion may have no association with M. bovis infection in GZAR. These results indicate that M. bovis infection in dairy cows was widespread in GZAR, and integrated strategies and measures should be performed to control and prevent M. bovis infection and disease outbreak.Key words: Mycoplasma bovis, seroprevalence, dairy cows, Guangxi Zhuang Autonomous Region (GZAR), China, enzyme-linked immunosorbent assay (ELISA)

Growth disturbance of extracts from several crops straw (residue) on Ageratina adenophora and biological-control implications in hazardous weed invasion for eco-restoration

Laboratory biological simulation experiment was conducted to investigate growth disturbance of high, moderate, low concentration of aqueous extracts (i.e. the original extracts with a solid liquid ratio of 1:40 g mL-1 and its 5 times diluents and 25 times diluents) from several crops straw (residue) on Ageratina adenophora, a worldwide notorious invasive weed. The results showed: (a) aqueous extracts from several crops straw (residue) brought about different impacts on the single index for germination and growth of A. adenophora, e.g., high concentration of aqueous extracts from Brassica oleracea waste leaves showed a strong inhibition against the germination rate (GR) and germination index (GI) of A. adenophora, while high concentration of aqueous extracts from Vicia cracca straw showed a strong inhibition against radicle length (RL) and hypocotyl length (HL) of A. adenophora; (b) high concentration of aqueous extracts from B. oleracea waste leaves and high, moderate and low concentration of aqueous extracts from Oryza sativa straw and Triticum aestivum straw showed rather strong synthetic effects (inhibition) on GR and GI of A. adenophora, which could be chosen for the control over the seeds germination of A. adenophora; (c) high and moderate concentrations of aqueous extracts from V. cracca straw, high concentration of aqueous extracts from B. campestris waste leaves, and moderate and low concentrations of aqueous extracts from O. sativa straw and T. aestivum straw showed rather strong synthetic effects (inhibition) on RL and HL of A. adenophora, which could be selected as ideal materials for the control over the seedlings growth of A. adenophora; and (d) high concentrations of aqueous extracts from V. cracca straw, B. oleracea waste leaves and B. campestris waste leaves, and high, moderate and low concentrations of aqueous extracts from O. sativa straw and T. aestivum straw showed rather strong synthetic effects (inhibition) on GR, GI, RL and HL of A. adenophora, which could be selected as ideal materials for the control over the seeds germination and seedlings growth of A. adenophora. Thus, this study would provide a theoretic guidance and technical support for the resources utilization of crops straw (residue) and the prevention and control over invasive weeds as well. (C) 2013 Elsevier B.V. All rights reserved.Laboratory biological simulation experiment was conducted to investigate growth disturbance of high, moderate, low concentration of aqueous extracts (i.e. the original extracts with a solid liquid ratio of 1:40 g mL-1 and its 5 times diluents and 25 times diluents) from several crops straw (residue) on Ageratina adenophora, a worldwide notorious invasive weed. The results showed: (a) aqueous extracts from several crops straw (residue) brought about different impacts on the single index for germination and growth of A. adenophora, e.g., high concentration of aqueous extracts from Brassica oleracea waste leaves showed a strong inhibition against the germination rate (GR) and germination index (GI) of A. adenophora, while high concentration of aqueous extracts from Vicia cracca straw showed a strong inhibition against radicle length (RL) and hypocotyl length (HL) of A. adenophora; (b) high concentration of aqueous extracts from B. oleracea waste leaves and high, moderate and low concentration of aqueous extracts from Oryza sativa straw and Triticum aestivum straw showed rather strong synthetic effects (inhibition) on GR and GI of A. adenophora, which could be chosen for the control over the seeds germination of A. adenophora; (c) high and moderate concentrations of aqueous extracts from V. cracca straw, high concentration of aqueous extracts from B. campestris waste leaves, and moderate and low concentrations of aqueous extracts from O. sativa straw and T. aestivum straw showed rather strong synthetic effects (inhibition) on RL and HL of A. adenophora, which could be selected as ideal materials for the control over the seedlings growth of A. adenophora; and (d) high concentrations of aqueous extracts from V. cracca straw, B. oleracea waste leaves and B. campestris waste leaves, and high, moderate and low concentrations of aqueous extracts from O. sativa straw and T. aestivum straw showed rather strong synthetic effects (inhibition) on GR, GI, RL and HL of A. adenophora, which could be selected as ideal materials for the control over the seeds germination and seedlings growth of A. adenophora. Thus, this study would provide a theoretic guidance and technical support for the resources utilization of crops straw (residue) and the prevention and control over invasive weeds as well. (C) 2013 Elsevier B.V. All rights reserved

Heavily electron-doped electronic structure and isotropic superconducting gap in AxFe2Se2 (A=K,Cs)

The low energy band structure and Fermi surface of the newly discovered superconductor, AxFe2Se2 (A=K,Cs), have been studied by angle-resolved photoemission spectroscopy. Compared with iron pnictide superconductors, AxFe2Se2 (A=K,Cs) is the most heavily electron-doped with Tc~30 K. Only electron pockets are observed with an almost isotropic superconducting gap of ~10.3 meV, while there is no hole Fermi surface near the zone center, which indicates the inter-pocket hopping or Fermi surface nesting is not a necessary ingredient for the unconventional superconductivity in iron-based superconductors. Thus, the sign changed s$_\pm$ pairing symmetry, a leading candidate proposed for iron-based superconductors, becomes conceptually irrelevant in describing the superconducting state here. A more conventional s-wave pairing is a better description.Comment: 4 pages, 4 figures, published online in Nature Materials 201

Atomic-scale combination of germanium-zinc nanofibers for structural and electrochemical evolution

Alloys are recently receiving considerable attention in the community of rechargeable batteries as possible alternatives to carbonaceous negative electrodes; however, challenges remain for the practical utilization of these materials. Herein, we report the synthesis of germanium-zinc alloy nanofibers through electrospinning and a subsequent calcination step. Evidenced by in situ transmission electron microscopy and electrochemical impedance spectroscopy characterizations, this one-dimensional design possesses unique structures. Both germanium and zinc atoms are homogenously distributed allowing for outstanding electronic conductivity and high available capacity for lithium storage. The as-prepared materials present high rate capability (capacity of similar to 50% at 20 C compared to that at 0.2 C-rate) and cycle retention (73% at 3.0 C-rate) with a retaining capacity of 546 mAh g(-1) even after 1000 cycles. When assembled in a full cell, high energy density can be maintained during 400 cycles, which indicates that the current material has the potential to be used in a large-scale energy storage system