Induction of small-segment-translocation between wheat and rye chromosomes

A new approach to produce wheat-rye translocation, based on the genetic instability caused by monosomic addition of rye chromosome in wheat, is described. 1 283 plants from the selfed progenies of monosomic addition lines with single chromosome of inbred rye line R12 and complete chromosome complement of wheat cultivar Mianyang 11 were cytologically analyzed on a plant-by-plant basis by the improved C-banding technique. 63 of the plants, with 2n = 42, were found containing wheat-rye translocation or substitution, with a frequency of 4. 91% . Compared with the wheat parent, other 32 plants with 2n = 42 exhibited obvious phenotypic variation, but their com-ponent of rye chromosome could not be detected using the C-banding technique. In situ hybridization with a biotin-la-beled DNA probe was used to detect rye chromatin and to determine the insertion sites of rye segments in the wheat chromosomes. In 20 out of the 32 variant wheat plants, small segments of rye chromosomes were found being inserted into dif     

The flora and biogeochemistry of the ultramafic soils of Goiás state, Brazil

Major collections of the ultramafic flora of Goiás, central Brazil, were made by Brooks and co-workers in 1988 and 1990. At the time of reports on this material in 1990–1992 much of it had been identified only tentatively and incompletely, but the area was clearly interesting for taxonomic and biogeochemical reasons. Further progress has been made but still only two-thirds of the specimens are identified at the species level. Following a third collection in early 2005, we now have 800 specimens from this area, with chemical analyses of all the plants and of more than 120 representative soil samples. New species have been found, e.g., in Paspalum (Poaceae) and Pterolepis (Melastomataceae). There is a need for more taxonomic work in genera such as Cnidoscolus (Euphorbiaceae), Lippia (Verbenaceae), Turnera and Piriqueta (Turneraceae), and Vellozia (Velloziaceae). Ni hyperaccumulation (>1,000 mg/kg in dry plant matter) has now been found in a total of 79 specimens, representing more than 30 different species. Notable Ni hyperaccumulators include Pfaffia sarcophylla (Amaranthaceae), species of Justicia, Lophostachys and Ruellia (Acanthaceae), Porophyllum (Asteraceae), several species of Lippia (Verbenaceae), Turnera and Piriqueta (Turneraceae), and a possibly new Cnidoscolus (Euphorbiaceae). Ni hyperaccumulation has not been found in plants of the outcrops of Morro Feio or Crominia-Mairipotaba; it seems to be confined to the extensive layered ultramafics of Barro Alto and the Macedo-Niquelandia areas. The distribution of Ni-values in the Brazilian plant collection is different from that found in the Mediterranean and California, where there is a clear distinction between accumulator and non-accumulator plants: in Brazil the distribution is more continuous, and median Ni concentrations are much greater. An ultramafic hill just north of Niquelandia deserves to be protected because of the presence there of many of the hyperaccumulators and species probably endemic to the Goiás ultramafics.     

Hyperaccumulation of nickel by two Alyssum species from the serpentine soils of Iran

Serpentine soils, which contain relatively high concentrations of nickel and some other metals, are the preferred substrate for some plants, especially those that accumulate Ni in their tissues. In temperate regions more Ni-hyperaccumulator plants are found in Alyssum than in any other genus. In this study, serpentine soils of two areas (Marivan and Dizaj) in the west/northwest of Iran and also perennial Alyssum plants growing on these soils were analyzed for Ni and some other metals. The highest concentrations of total metals in the soils of these areas for Ni, Cr, Co and Mn were 1,350, 265, 94 and 1,150 μg g⁻¹, respectively, while concentrations of Fe, Mg and Ca reached 3.55%, 16.8% and 0.585% respectively. The concentration of exchangeable Ni in these soils is up to 4.5 μg g⁻¹. In this study two Alyssum species, A. inflatum and A. longistylum, have been collected from Marivan and Dizaj, respectively. Analysis of leaf dry matter shows that they can contain up to 3,700 and 8,100 μg Ni g⁻¹, respectively. This is the first time that such high Ni concentrations have been found in these species. The concentrations of other metals determined in these species were in the normal range for serpentine plants, except for Ca, which was higher, up to 5.3% and 3.5%, respectively     

Boron translocation in coffee trees

Boron deficiency in coffee trees (Coffea arabica) is widespread, however, responses to B fertilizer have been erratic, depending on the year, method, and time of application. A better understanding of B uptake, distribution, and remobilization within the plant is important in developing a rational fertilization program. Field and greenhouse experiments were conducted to study B distribution and remobilization in coffee trees. Boron was provided either in the nutrient solution or sprayed on the leaves of trees grown under adequate or transient B deficiency. There was clear evidence for B translocation via symplast (remobilization) to coffee grains, even in well-nourished plants. When ¹⁰B was present in the nutrient solution during most part of fruit filling, from 33 to 40% of the B found in coffee fruits was absorbed during this period, depending on the timing and duration of the B deficiency treatment. In the field, when B was sprayed once on the leaves, around 4% of the fruit B was derived from the foliar fertilizer. Boron remobilization within coffee trees is limited in well nourished plants, but it can be significant during periods of temporary B deficiency in plants otherwise well nourished with B. The implications of these findings for B fertilization practice, are discussed.     

Heterometallic Ni/Zn amine complexes possessing extended 2D and 3D hydrogen-bonded networks prepared from zinc oxide

Five novel heterometallic Ni/Zn coordination compounds [Ni(en)₃][ZnCl₄] (1), [Ni(en)(Hea)₂][ZnCl₄] (2), [Ni(dien)₂][ZnCl₄] (3), [Ni(en)₃][ZnCl₄] · 2DMSO (4) and [Ni(en)₃][Zn(NCS)₄] · CH₃CN (5), where en = ethylenediamine (ethane-1,2-diamine), Hea = monoethanolamine (2-aminoethanol) and dien = diethylenetriamine (1,4,7-triazaheptane), have been synthesized by means of the open-air reaction of zinc oxide, nickel chloride (or nickel powder), NH₄X (X = Cl, NCS) and ligand (en, dien, Hea) in non-aqueous solvents, such as DMSO, DMF, CH₃OH and CH₃CN. The choice of a counter-anion in the initial ammonium salt as well as selection of the ligand and solvent provides an effortless approach to the controlled assembly of two- or three-dimensional extended networks assisted by hydrogen bonding. Crystallographic investigations reveal that 1, 2 and 5 possess 3D, while 3 and 4 exhibit 2D H-bonded crystal structures. The structures of the compounds exhibit six-coordinated Ni(II) centers and four-coordinated Zn(II) centers in distorted octahedral and tetrahedral geometries, respectively.     

St Lucia Whiptail Lizard Cnemidophorus vanzoi (Sauria: Teiidae) microsatellite primers

Eight polymorphic microsatellite loci have been characterized for the endangered St Lucia Whiptail Lizard Cnemidophorus vanzoi. Endemic to two small islets, Maria Major and Maria Minor, off the coast of St Lucia, Lesser Antilles, the world population is estimated at < 1000 individuals. However, representatives of the systematically complex genus Cnemidophorus, containing sexual species and parthenogenetic allopolyploids, are distributed widely in North, Central and South America, and on several islands in the Caribbean Sea. These microsatellite markers are being used to monitor the genetic structure of a population of St Lucia Whiptails, recently founded through translocation, on the nearby Praslin Island.     

Wnt signaling regulates experience-dependent synaptic plasticity in the adult nervous system

Comment on: Jensen M, et al. Cell 2012; 149:173-87.     

Development of Triticum aestivum-Leymus racemosus translocation lines using gametocidal chromosomes

Maan[1] and Endo[2] et al. first reported that some chromosomes from Ae. longgissima, Ae. sharonensis and Ae. triuncialis showed preferential transmission when introduced into wheat background. The mechanism for this phenomenon rests with the fact that contrary to the normal fertility of gametes with these chromosomes, chromosome structural aberrations occur seriously in the gametes without these chromosomes, causing less compatibility in selective fertilization and resulting in semi-sterilit…     

腹部手术与肠道细菌移位和内源性感染

目的 人体肠道定植着大量的细菌,正常情况下肠道菌群与机体处于动态平衡,腹部外科手术的刺激和创伤可以破坏肠道正常的菌群结构和屏障功能,使细菌的数量、比例发生改变或空间上发生移位,引发内源性感染,最终导致机体各种功能障碍.研究分析腹部外科手术对肠道细菌及屏障功能的影响,为今后预防和治疗提供理论依据.