Regular Production of Transgenic Wheat Mediated by Agrobacterium tumefaciens

Wheat is the number one crop both in acreage and total yield in the world. Therefore, it is very important to improve wheat by gene engineering techniques even though it belongs to the plants insensitive to gene transformation, especially to Agrobacterium-mediated transformation. Wheat immature embryos of 1.0-1.5mm in size, C58c1 of Agrobacterium strain harboring pPTN249, pPTN270, pPTN254, and pSIS-GFP respectively (all the vectors contain the aphA selectable gene driven by enhanced 35S promoter and a target gene controlled by ubi promoter or E35S promoter), AB medium for Agrobacterium activate culture, WCC medium for co-culture, were used in this study. The embryos with 4 days of pre-culture were transferred onto selection medium with 10mg/L geneticin, 50mg/L ticarcillin, 50mg/L vancomycin, and 50mg/L cefotaxine after 30 minutes of infection and 2 days of co-cultivation with Agrobacterium. Followed callus production,shoot regeneration on selection medium, 114 resistant plantlets were obtained from 10 transformation experiments of four genotypes. By nptⅡ ELISA (nptⅡ enzyme assay), PCR, Southern blot and leaf bleach,29 positive plants were identified from two genotypes of Bobwhite and Yanglmai 10, with an average transformation efficiency of 0.82 %. The result tested by Southern blot also showed that the transgenic plants with single- copy integration of target gene took 65.52% among total positive plants. The ELISA value of transgenic plant was also related to the copies of alien DNA integrating into wheat chromosomes, the transgenic plants with single copy integration giving higher ELISA value than the ones with 2 or 3 copies integration.     

Atmospheric methane and nitrous oxide of the Late Pleistocene from Antarctic ice cores

The European Project for Ice Coring in Antarctica Dome C ice core enables us to extend existing records of atmospheric methane (CH4) and nitrous oxide (N2O) back to 650,000 years before the present. A combined record of CH4 measured along the Dome C and the Vostok ice cores demonstrates, within the resolution of our measurements, that preindustrial concentrations over Antarctica have not exceeded 773 +/- 15 ppbv (parts per billion by volume) during the past 650,000 years. Before 420,000 years ago, when interglacials were cooler, maximum CH4 concentrations were only about 600 ppbv, similar to lower Holocene values. In contrast, the N2O record shows maximum concentrations of 278 +/- 7 ppbv, slightly higher than early Holocene values.     

Role for piRNAs and noncoding RNA in de novo DNA methylation of the imprinted mouse Rasgrf1 locus

Genomic imprinting causes parental origin-specific monoallelic gene expression through differential DNA methylation established in the parental germ line. However, the mechanisms underlying how specific sequences are selectively methylated are not fully understood. We have found that the components of the PIWI-interacting RNA (piRNA) pathway are required for de novo methylation of the differentially methylated region (DMR) of the imprinted mouse Rasgrf1 locus, but not other paternally imprinted loci. A retrotransposon sequence within a noncoding RNA spanning the DMR was targeted by piRNAs generated from a different locus. A direct repeat in the DMR, which is required for the methylation and imprinting of Rasgrf1, served as a promoter for this RNA. We propose a model in which piRNAs and a target RNA direct the sequence-specific methylation of Rasgrf1.     

Discovery of a Jupiter/Saturn analog with gravitational microlensing

Searches for extrasolar planets have uncovered an astonishing diversity of planetary systems, yet the frequency of solar system analogs remains unknown. The gravitational microlensing planet search method is potentially sensitive to multiple-planet systems containing analogs of all the solar system planets except Mercury. We report the detection of a multiple-planet system with microlensing. We identify two planets with masses of approximately 0.71 and approximately 0.27 times the mass of Jupiter and orbital separations of approximately 2.3 and approximately 4.6 astronomical units orbiting a primary star of mass approximately 0.50 solar mass at a distance of approximately 1.5 kiloparsecs. This system resembles a scaled version of our solar system in that the mass ratio, separation ratio, and equilibrium temperatures of the planets are similar to those of Jupiter and Saturn. These planets could not have been detected with other techniques; their discovery from only six confirmed microlensing planet detections suggests that solar system analogs may be common.     

Magnetoencephalography and epilepsy research

Magnetoencephalography is the detection of the magnetic field distribution across the surface of the head, which is generated by a neuronal discharge within the brain. Magnetoencephalography is used in clinical epilepsy to localize the epileptogenic region prior to its surgical removal. A discussion of the instrumentation based on the superconducting quantum interference device that is used for detecting the magnetic field distribution, the analytical techniques, current research, and future directions of magnetoencephalography in epilepsy research is presented.     

Molecular Growth Requirements of Single Mammalian Cells

The molecular nutritional requirements exhibited by mammalian cells can vary with the following conditions: whether the cells are plated singly or in massive inoculum; whether a clonal strain or a mixture of different genotypes is employed; whether the macromolecular fraction of serum used as a supplement was previously exposed to prolonged dialysis or other procedures which may release bound micromolecules. In addition, the nature of the medium in which the cells were previously grown, the time permitted for incubation of the cells in the test medium, and the presence of substances or conditions which may specifically introduce the need for certain molecules to preserve balance can strongly influence nutritional requirements. This great versatility may reflect the ability of the mammalian cell to assume different metabolic states characteristic of specific types of differentiation. Under certain conditions, growth of single HeLa cells of the S3 clonal strain requires the presence of cholesterol at a level of 0.5 to 1 microgram per milliliter.     

A gain-of-function mutation in a cytokinin receptor triggers spontaneous root nodule organogenesis

Legume root nodules originate from differentiated cortical cells that reenter the cell cycle and form organ primordia. We show that perception of the phytohormone cytokinin is a key element in this switch. Mutation of a Lotus japonicus cytokinin receptor gene leads to spontaneous development of root nodules in the absence of rhizobia or rhizobial signal molecules. The mutant histidine kinase receptor has cytokinin-independent activity and activates an Escherichia coli two-component phosphorelay system in vivo. Mutant analysis shows that cytokinin signaling is required for cell divisions that initiate nodule development and defines an autoregulated process where cytokinin induction of nodule stem cells is controlled by shoots.     

A rubberlike stretchable active matrix using elastic conductors

By using an ionic liquid of 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, we uniformly dispersed single-walled carbon nanotubes (SWNTs) as chemically stable dopants in a vinylidene fluoride-hexafluoropropylene copolymer matrix to form a composite film. We found that the SWNT content can be increased up to 20 weight percent without reducing the mechanical flexibility or softness of the copolymer. The SWNT composite film was coated with dimethyl-siloxane-based rubber, which exhibited a conductivity of 57 siemens per centimeter and a stretchability of 134%. Further, the elastic conductor was integrated with printed organic transistors to fabricate a rubberlike active matrix with an effective area of 20 by 20 square centimeters. The active matrix sheet can be uniaxially and biaxially stretched by 70% without mechanical or electrical damage. The elastic conductor allows for the construction of electronic integrated circuits, which can be mounted anywhere, including arbitrary curved surfaces and movable parts, such as the joints of a robot's arm.     

Adrenergic excitation of cutaneous pain receptors induced by peripheral nerve injury

The mechanisms by which peripheral nerve injuries sometimes lead to causalgia, aberrant burning pain peripheral to the site of nerve damage, are uncertain, although the sympathetic nervous system is known to be involved. Whether such syndromes could be the result of the development of responsiveness by some cutaneous pain receptors (C-fiber nociceptors) to sympathetic efferent activity as a consequence of the nerve injury was tested in an animal model. After nerve damage but not in its absence, sympathetic stimulation and norepinephrine were excitatory for a subset of skin C-fiber nociceptors and enhanced the responsiveness of these nociceptors to tissue-damaging stimulation. These effects were demonstratable within days after nerve lesions, occurred at the cutaneous receptive terminal region, were manifest in sensory fibers that had not degenerated after the injury, and were mediated by alpha 2-adrenergic-like receptors.