Inducible Formation of Glutamate Dehydrogenase in Rice Plant Roots by the Addition of Ammonia to the Media

The activity of glutamate dehydrogenase (l-glutamate: NAD oxidoreductase, EC 1.4.1.2.; GDH) of rice plants changes in response to the nitrogen source supplied to the culture solution. The activity of NADH-GDH(aminating) in roots is rapidly increased by the addition of ammonia, whereas the activity in shoots is much less affected by nitrogen supply. The activity increased with increasing concentration of ammonia at least up to 14.3 mM. In roots GDH activity was found in both the mitochondrial and soluble fractions. The increase of NADH-GDH activity caused by the ammonia treatment occurs mainly in the latter fraction. The new band with GDH activity was detected on the zymogram of polyacrylamide gel electrophoresis and this inducible enzyme is active with both NAD and NADP. On the other hand, the constitutive enzyme activity active with NAD is also increased by the ammonia treatment. The increase of enzyme activity is prevented by the addition of cycloheximide or chloramphenicol to culture medium. The incorporation of ¹⁴C-leucine(U) into GDH proteins was also studied using polyacrylamide gel electrophoresis. Higher radioactivity was found in induced samples than in non-induced ones. These results show that the increase of GDH activity in roots by ammonia treatment seems to depend on de novo protein synthesis.     

Review of the East Asian species of the genera Hybrizon Fallén and Ghilaromma Tobias (Hymenoptera: Ichneumonidae: Hybrizontinae)

East Asian species of the genera Hybrizon and Ghilaromma are reviewed. Four species of Hybrizon, H. buccatus (Brébisson 1825), H. ghilarovi Tobias, 1988, H. juncoi (Ceballos 1957) and H. flavofacialis Tobias, 1988 and two species of Ghilaromma, G. orientalis Tobias, 1988 and G. ussuriensis Tobias, 1988, were recognized. H. ghilarovi was recorded from Korea, Japan and China, while H. juncoi was recorded from Korea, for the first time. The specimens recorded from Japan as G. fuliginosi (Wilkinson, 1930) by Watanabe (1984) are referred to G. orientalis herein. This species is newly recorded from Korea and Japan. Keys to East Asian species of Hybrizon and the world species of Ghilaromma are also provided.     

Two new species of the genus Carminator Shaw from Japan, the northernmost record of extant Megalyridae (Hymenoptera)

The family Megalyridae is recorded from Japan for the first time on the basis of two new species, Carminator helios and C. japonicus. This is the northernmost record of living Megalyridae, although fossil species are known from regions of the Baltic Sea. Carminator helios can be distinguished from congeners of the Asian and Australian regions by the combination of a long head, deeply excavated frons with convex inner margins, entirely striated postgena, the number of fore tibial spines (more than 16), and a long R₁ vein. Carminator japonicus is distinguishable from other species by the combination of an orange‐colored metasoma, a weakly excavated frons, and an elongate vertex. This species was collected from the canopy of Acer pictum. Additional characters that distinguish species of the genus Carminator are discussed.     

Microbial production of isotopically light iron(II) in a modern chemically precipitated sediment and implications for isotopic variations in ancient rocks

The inventories and Fe isotope composition of aqueous Fe(II) and solid‐phase Fe compounds were quantified in neutral‐pH, chemically precipitated sediments downstream of the Iron Mountain acid mine drainage site in northern California, USA. The sediments contain high concentrations of amorphous Fe(III) oxyhydroxides [Fe(III)_am] that allow dissimilatory iron reduction (DIR) to predominate over Fe–S interactions in Fe redox transformation, as indicated by the very low abundance of Cr(II)‐extractable reduced inorganic sulfur compared with dilute HCl‐extractable Fe. δ⁵⁶Fe values for bulk HCl‐ and HF‐extractable Fe were ≈ 0. These near‐zero bulk δ⁵⁶Fe values, together with the very low abundance of dissolved Fe in the overlying water column, suggest that the pyrite Fe source had near‐zero δ⁵⁶Fe values, and that complete oxidation of Fe(II) took place prior to deposition of the Fe(III) oxide‐rich sediment. Sediment core analyses and incubation experiments demonstrated the production of millimolar quantities of isotopically light (δ⁵⁶Fe ≈ ?1.5 to ?0.5‰) aqueous Fe(II) coupled to partial reduction of Fe(III)_am by DIR. Trends in the Fe isotope composition of solid‐associated Fe(II) and residual Fe(III)_am are consistent with experiments with synthetic Fe(III) oxides, and collectively suggest an equilibrium Fe isotope fractionation between aqueous Fe(II) and Fe(III)_am of approximately ?2‰. These Fe(III) oxide‐rich sediments provide a model for early diagenetic processes that are likely to have taken place in Archean and Paleoproterozoic marine sediments that served as precursors for banded iron formations. Our results suggest pathways whereby DIR could have led to the formation of large quantities of low‐δ⁵⁶Fe minerals during BIF genesis.     

New distributional and host records for the parasitoid Gronotoma adachiae (Hymenoptera: Figitidae: Eucoilinae) in Asia

The parasitoid Gronotoma adachiae is reported from Vietnam for the first time. The vegetable leaf miner Liriomyza sativae (Diptera: Agromyzidae) is a new host record. The G. adachiae specimens collected in Yunnan Province are the second record of this parasitoid from China.     

Taxonomic status of Amebachia Uchida in the genus Netelia Gray (Hymenoptera; Ichneumonidae; Tryphoninae) with descriptions of four new species from Japan

The lectotype of Amebachia baibarana Uchida, 1928, which is the type species of Amebachia Uchida, was re‐examined. Though this species was synonymized with Netelia (Netelia) laevis (= Paniscus laevis Cameron, 1905) and Amebachia has been synonymized under the subgenus Netelia of the genus Netelia, it is concluded that A. baibarana is a distinct species from N. laevis and Amebachia should be a subgenus of the genus Netelia. Netelia laevis is transferred from the subgenus Netelia to Apatagium. Four new species of Netelia (Amebachia), N. (A.) yoshimatsui sp. nov., N. (A.) rasilella sp. nov., N. (A.) fulvistigma sp. nov., and N. (A.) vicinalis sp. nov. are described from Japan, and a key to the species of this subgenus is provided.     

Acetylcholine mimics Crossed Olivocochlear Bundle Stimulation

ELECTRICAL stimulation of the crossed olivocochlear bundle (COCB) results in an inhibition of the auditory nerve compound action potential¹, an augmentation of cochlear microphonics² and a slow negative potential change in the scala media³. These changes have been shown to be blocked by anticholinergics applied to the scala tympani^4,5 and Cholinesterase had been associated with the presence of COCB nerve endings in the cochlea⁶. Thus, it seems that acetylcholine may be the inhibitory transmitter of the COCB.