Cable bacteria (CB) are filamentous Desulfobulbaceae that split the energy-conserving reaction of sulfide oxidation into two half reactions occurring in distinct cells. CB can use nitrate, but the ...reduction pathway is unknown, making it difficult to assess their direct impact on the N-cycle. Here we show that the freshwater cable bacterium Ca. Electronema sp. GS performs dissimilatory nitrate reduction to ammonium (DNRA).
NO
-amended sediment with Ca. Electronema sp. GS showed higher rates of DNRA and nitrite production than sediment without Ca. Electronema sp. GS. Electron flux from sulfide oxidation, inferred from electric potential (EP) measurements, matched the electron flux needed to drive CB-mediated nitrate reduction to nitrite and ammonium. Ca. Electronema sp. GS expressed a complete nap operon for periplasmic nitrate reduction to nitrite, and a putative octaheme cytochrome c (pOCC), whose involvement in nitrite reduction to ammonium remains to be verified. Phylogenetic analysis suggests that the capacity for DNRA was acquired in multiple events through horizontal gene transfer from different organisms, before CB split into different salinity niches. The architecture of the nitrate reduction system suggests absence of energy conservation through oxidative phosphorylation, indicating that CB primarily conserve energy through the half reaction of sulfide oxidation.
Phylogeography combines geographic information with phylogenetic analysis to gain insight into the origin, dispersal, and speciation dynamics of populations. Advances in the utility of Next ...Generation Sequencing technology has led to a shift toward whole genome sequencing for analyzing contemporary geographic patterns and how they have arisen. A geographic area and its history can help to tell a story of how organisms change genetically over time. This idea is illustrated by one area of geography that was affected by climatic conditions during the Pleistocene epoch. During the Pleistocene, the monsoon tropics of Northern Australia were affected by climatic and sea level fluctuations due to global cycles of glaciation and glacial receding in other areas of earth that altered sea levels intermittently across the region. This caused formation and deformation of a land bridge comprising a 150km area separating the Top End of Australia from the Cape York Peninsula This is the so- called Carpentarian Barrier (CB) and numerous studies investigating many clades have shown replicated vicariance around this barrier due to intermittent genetic exchange. Two sister species from the genus Climacteris have ranges that the CB splits with negligible overlap. Climacteris melanura and Climacteris picumnus range to the west and to the east of the barrier, respectively. Therefore, we hypothesize that these species have formed by intermittent gene exchange caused by the opening and the closing of the land bridges over time. There should be evidence of introgression and reticulate evolution when comparing populations to the east of the CB and to the west of the CB. This study looks for this evidence by performing whole genome resequencing of populations on both sides of the barrier and mapping these sequences to a de novo Reference of a C. picumnus individual. We find that there is evidence of introgression between C. melanura to the west of the CB and C. picumnus to the east of the CB by performing ABBA-BABA analysis on individuals around the barrier. We support this finding with additional investigation into statistical measures that infer genetic diversity and variability (π, polymorphic sites and Principal Component Analysis). This study will add to other similar investigations on this area and may add to the growing breadth of insight that could lead to signals of gene tree heterogeneity across Northern Australia.
The effects of the pretreatment and/or the media during splitting of bovine blastocysts derived from in vitro-fertilization on the success of bisection and the viability of demi embryos were ...examined. Test groups were as below; exposed in cytochalasin B (CB) solution before bisection then split in the solution with CB (CB-CB) or without CB (CB-PBS), exposed in Casup(2+) free PBS then split in DPBS (PBS (-)), or split in sucrose solution without pretreatment (SUC). Bisections were performed vertically by a metal blade equipped to the micromanipulator without holding pipette. The shrinkage of embryos in splitting solution before bisection, the explosion of zona pellucida at the time of bisection, and the volume and quality of demi embryos just after bisection was recorded. The viability of demi embryos was evaluated by morphological observation after 24h of culture. The cell numbers of demi embryos were counted, and the differences of cell number between each demi-pair were calculated. In CB-P8S and SUC groups, explosion of zona pellucida and damage to embryos were reduced because of the shrinkage of an embryo. CB-CB and CB-PBS groups had many cell numbers of demi embryos, so that an effect of CB to restrain a loss of cells was suggested. On the other hand, in PBS (-) group, it was suggested that there were few effects to reduce the damage of embryos at the time of bisection, because there were low survival rate and few cell numbers of the demi embryos. In addition, the difference of cell number between each demi-pair did not show a significantly difference among the groups.
碩士
國立臺灣大學
政治學研究所
100
Citizen’s support of checks-and-balances (CB) is one of the most important democratic values in developing and consolidating democracy, a belief that compromise is both necessary ...and desirable. Do Taiwanese voters support the idea of CB? What are the theoretical and practical issues in analyzing attitude toward CB? Are those CB attitudes measured nowadays the same as what they apparently are? What are the origin and explanation of diverse types of CB support among Taiwanese voters?
Taiwan had just experienced the first split-government during 2000-2008. In 2004 congressional election, the incumbent pan-green camp attracted voters by the slogan of “unified and then efficient government”, while the opposite pan-blue camp appealed to voters for the value of constitutional balances. Yet, once the pan-blue camp won back both of the congress and president seats in 2008, the two camps opted for the government structure to which they previously opposed. The dramatic position switch is a rare and
A gas chromatographic method was developed to directly determine the enantiomers of acrylic ketone alcohol and acrylic ketone acetate. Two pairs of enantiomers were nearly baseline-separated by using ...Model HP-5890 Gas Chromatograph with flame ionization detector and WCOT CD-Chiral-DEX CB (30 m x 0.25 mm i.d.) column. The optimum conditions were the split ratio of 30:1 for the sample injected, the flow rates of 3.7 mL/min for the carrier gas (nitrogen), 60 mL/min for the hydrogen, and 250 mL/min for the oxygen, and temperatures of 148 degrees C for the column, 230 degrees C for the injector, and 230 degrees C for the detector. The linearity and reproducibility were satisfactory. The regression coefficients were over 0.9965. The RSDs obtained were less than 1.25%. The method was further used to trace the reactants and products, and to evaluate the enzyme catalyst activity and selectivity under different conditions. The results show that the method developed is very successful.
Diesel engines equipped with Diesel Particulate Filter（DPF） system have a significant problem regarding oil dilution caused by post injection during DPF regeneration. In this paper, the measurement ...of oil dilution rate using a carbon balance (CB) method were established at first. Then, in order to clarify the detailed mechanism of oil dilution, the effects of injection pattern and fuel properties on oil dilution and fuel evaporation in crankcase were experimentally investigated. The experimental results show that the split injection is effective to reduce the oil dilution especially at high ambient gas temperatures, although the effect becomes smaller with decreasing the ambient gas temperature. Furthermore, the fuel components strongly affect the fuel evaporation rate in the diluted oil.
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