Molecular cloning and characterization of the germline-restricted chromosome sequence in the zebra finch

The zebra finch (Taeniopygia guttata) germline-restricted chromosome (GRC) is the largest chromosome and has a unique system of transmission in germ cells. In the male, the GRC exists as a single heterochromatic chromosome in the germline and is eliminated from nuclei in late spermatogenesis. In the female, the GRC is bivalent and euchromatic and experiences recombination. These characteristics suggest a female-specific or female-beneficial function of the GRC. To shed light on the function of GRC, we cloned a portion of the GRC using random amplified polymorphic DNA–polymerase chain reaction and analyzed it using molecular genetic and cytogenetic methods. The GRC clone hybridized strongly to testis but not blood DNA in genomic Southern blots. In fluorescent in situ hybridization analysis on meiotic chromosomes from synaptonemal complex spreads, the probe showed hybridization across a large area of the GRC, suggesting that it contains repetitive sequences. We isolated a sequence homologous to the GRC from zebra finch chromosome 3 and a region of chicken chromosome 1 that is homologous to zebra finch chromosome 3; the phylogenetic analysis of these three sequences suggested that the GRC sequence and the zebra finch chromosome 3 sequence are most closely related. Thus, the GRC sequences likely originated from autosomal DNA and have evolved after the galliform–passeriform split. The present study provides a foundation for further study of the intriguing GRC

Propane Dehydrogenation by Autothermal Reforming

The proposed design is for the the production of propene through propane dehydrogenation using Thyssen Krupp’s STAR technology and a hybrid membrane separation. The plant has a capacity of 700 kT/yr and will be located in the Middle East. At current propane/propene prices, the use of Thyssen Krupp’s STAR process and hybrid membrane separation is not economical and has a negative IRR. The NPV of this project at current market prices is -$865MM. However, economic feasibility depends on volatile market conditions. The process begins with the oxydehydrogenation section, consisting of four reformers connected to four oxyreactors that are cycled to allow for regeneration of the .2-.6%Pt- Sn/ZnAl2O5 catalyst. In order to produce polymer grade propene, a separation is needed following dehydrogenation. Separation operations include adsorption, MEA absorption system, distillation, and a hybrid distillation/membrane C3 splitter

FISH analysis and cytogenetic characterization of male meiotic prophase I in Acricotopus lucidus (Diptera, Chironomidae)

ABSTRACT. In the chironomid Acricotopus lucidus, two cells with quite different chromo some complements arise from the last unequal spermato-gonial mitosis, as a consequence of monopolar migration of the so-called germ line limited chromosomes (Ks). The cell receiving all the Ks, in ad-dition to two sets of the regularly segregating somatic chromosomes (Ss), develops into the primary spermatocyte, while the cell getting only Ss dif-ferentiates into an aberrant spermatocyte. Only the primary spermatocyte enters meiosis. These nuclear events in the primary spermatocytes of A. lucidus during prophase I were analyzed by carmine-orcein staining, sil-ver impreg nation, live-cell RNA fluorescence labeling, and fluorescence in situ hybridization, using painting probes of the three Ss and the K centromeres. Early prophase I nuclei display large con densed chromatin blocks showing intense carmine staining, dark silver nitrate impregnation and bright DAPI fluores cence. The first clear signs of meiotic prophase progression are loops arising at early pachytene, which originate from th

External high-Quality-factor Resonator tunes up nuclear magnetic resonance

The development of powerful sensors for the detection of weak electromagnetic fields is crucial for many spectroscopic applications, in particular for nuclear magnetic resonance (NMR). Here, we present a comprehensive theoretical model for boosting the NMR signal-to-noise ratio, validated by liquid-state 1H, 129Xe and 6Li NMR experiments at low frequencies, using an external resonator with a high quality-factor combined with a low-quality-factor input coil. In addition to an enhanced signal-to-noise ratio, this approach exhibits striking features such as a high degree of flexibility with respect to input coil parameters and a square-root dependence on the sample volume, and signifies an important step towards compact NMR spectroscopy at low frequencies with small and large coils