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In the koji molds Aspergillus sojae and Aspergillus oryzae, exogenous DNA is integrated in the genome, in most cases irrespective of the sequence homology, suggesting that DNA integration occurs predominantly through a nonhomologous end joining pathway where two ku genes, namely, ku70 and ku80, play a key role. To determine the effect of ku gene disruption on the gene targeting frequency, we constructed ku70-, ku80-, and ku70-ku80-disrupted strains of A. sojae and A. oryzae. The gene targeting frequency of the tannase gene in ku70 and ku80 strains of both Aspergillus species was markedly enhanced as compared with that of the parental strains. The gene targeting frequency of the aflR and ku80 genes was also enhanced in an A. sojae ku70 background. Therefore, the koji mold strains with ku-disrupted genes will be excellent tools as hosts for efficient gene targeting.

From a detailed study, including polarization dependence, of the normal state angle-resolved photoemission spectra for Bi 2 Sr 2 CaCu 2 O 8 , we find only one CuO 2 band related feature. All other spectral features can be ascribed either to umklapps from the superlattice or to "shadow bands." Even though the dispersion of the peaks looks like band theory, the line shape is anomalously broad and no evidence is found for bilayer splitting. We argue that the "dip feature" in the spectrum below T c arises not from bilayer splitting, but rather from many-body effects.

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Andosols (or Andisols) possess several distinctive properties that are rarely found in other groups of soils. These properties are largely due to the dominance of short-range-ordered minerals (allophane, imogolite and ferrihydrite) and/or metal-humus complexes (Al/Fe-humus complexes) in their colloidal fraction. While several papers have extensively reviewed the nature and properties of short-range-ordered minerals, there is no comprehensive review of the genesis, characteristics and management implications of Al-humus complexes, the dominant form of active Al in non-allophanic Andosols. In this review, we survey the chemical characteristics of Al-humus complexes and discuss the pedogenic environment favoring their formation in non-allophanic Andosols. The role of Al-humus complexes in carbon cycling and soil organic carbon accumulation is emphasized as an important mechanism controlling organic dynamics in Andosols. While non-allophanic Andosols share many common properties with allophanic Andosols, they display several distinct characteristics associated with Al-humus complexes, such as strong acidity and high exchangeable Al content that impair agricultural productivity due to Al phytotoxicity. Thus, we focus on the role of Al-humus complexes in regulating aqueous Al 3+ solubility and release/retention kinetics, Al phytotoxicity, phosphorus dynamics, and suppression of soil-borne diseases. Knowledge of these soil properties as related to Al-humus complexes is necessary to develop effective soil management practices to assure sustainable agricultural productivity in non-allophanic Andosols. Finally, future research needs are identified concerning the role of Al-humus complexes in regulating soil biogeochemical processes.

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