Effects of a Plant Growth Regulator, Prohexadione Calcium (BX-112), on the Elongation of Rice Shoots Caused by Exogenously Applied Gibberellins and Helminthosporol, Part II

Prohexadione calcium (BX-112) is a novel plant growth regulatorthat inhibits the late stages of the biosynthesis of gibberellinsin plants. Fourteen kinds of gjbberellin, helminthosporol and'helminthosporic acid were applied simultaneously with BX-112to rice seedlings (Oryza sativa L. ), and their growth-promotingactivities in terms of shoot elongation were examined. The growth-promotingactivities of GA₁, GA₄, GA₁₈, GA₂₂, GA₂₃, GA₃₈, helminthosporoland helminthosporic acid were not inhibited by BX-112, but thoseof GA₅, GA₉, GA₁₅, GA₁₉, GA₂₀, GA₃₁, GA₄₄ and GA₅₃ were inhibited.These results suggest that 3ß-hydroxylation is animportant and necessary step in the biosynthesis of gibberellinsthat promote shoot elongation in rice seedlings. The weak promotionof shoot elongation by GA₂₂ in the presence of BX-112 suggeststhat the effect of a hydroxyl group at C-18 of GA₂₂ might beable to mimic the effect of the 3ß-hydroxyl groupof GA₁. Helminthosporol and helminthosporic acid may promotethe shoot elongation of rice by mimicking physiologically activegibberellins and not by stimulating their biosynthesis. ¹Part I is the previous paper by Nakayama et al. (1990a) ³Present address: Frontier Research Program RIKEN, Wako-shi,Saitama, 351-01 Japan. (Received June 26, 1991; Accepted September 4, 1991)     

Vertical movement of dolphinfish <Emphasis Type="Italic">Coryphaena hippurus</Emphasis> as recorded by acceleration data-loggers in the northern East China Sea

Environmental changes influence foraging behavior for most animals. Dolphinfish, Coryphaena hippurus, are epipelagic predators and have a cosmopolitan tropical to warm-temperate (>20°C) distribution. We simultaneously obtained the ambient temperature and the foraging behavior (i.e., swimming speed, depth and tailbeat acceleration) of dolphinfish, using an acceleration data-logger in May, September, October, November 2007, June 2008, May and July 2010 for 8 individuals. Although the dolphinfish spent a mean ± standard deviation of 43.4 ± 27.7% of their time at the surface (0–5 m), dive excursions from the surface (DES) were observed in all individuals and maximum DES depths ranged from 50.1 to 95.4 m. DES events resulted dives below the thermocline for these dolphinfish, and there was a significantly positive relationship between the isothermal layer depth (ILD) and DES depth. Our results demonstrate that dolphinfish avoided the rapid thermal change beyond the thermocline, and their prey is most likely found in the upper layers of the thermocline. Gliding behavior during the DES phase was also observed and dolphinfish gradually descended to deeper waters with gliding. The gliding time was longer when the ILD was deeper, and fish tended to dive deeper. We suggest that dolphinfish adopt gliding behavior to search a broader range of depths for prey, while minimizing energy use.     

Survival of human enteroviruses in the Hawaiian ocean environment: evidence for virus-inactivating microorganisms.

The stability of certain human enteroviruses in the Hawaiian ocean environment was examined. The present data indicated that the time for 90% reduction of poliovirus type 1 at 24 +/- 1 degree C in seawater samples obtained from different sites in Hawaii ranged from 24 to 48 h, and complete inactivation occurred within 72 to 96 h. The accumulated evidence also strongly indicated that a virus-inactivating agent(s) of a microbiological nature was present in both clean and sewage-polluted seawaters, but not in fresh, mountain stream waters. The antiviral activity was lost when the seawater samples were subjected to boiling, autoclaving, or filtration through a 0.22- or 0.45-micrometer, but not a 1.0-micrometer, membrane filter. That the antiviral activity of the seawater was related to the growth activities of microorganisms was corroborated by the observed effects of added nutrients, a lower temperature of incubation, and the presence of certain antibiotics. Other enteric viruses, such as coxsackie virus B-4 and echo virus-7, were also shown to be similarly inactivated in seawater.     

An E3 ubiquitin ligase,ERECT LEAF1, functions in brassinosteroid signaling of rice

A spontaneous rice mutant, erect leaf1 (elf1–1), produced a dwarf phenotype with erect leaves and short grains. Physiological analyses suggested that elf1–1 is brassinosteroid-insensitive, so we hypothesized that ELF1 encodes a positive regulator of brassinosteroid signaling. ELF1, identified by means of positional cloning, encodes a protein with both a U-box domain and ARMADILLO (ARM) repeats. U-box proteins have been shown to function as E3 ubiquitin ligases; in fact, ELF1 possessed E3 ubiquitin ligase activity in vitro. However, ELF1 itself does not appear to be polyubiquitinated. Mutant phenotypes of 2 more elf1 alleles indicate that the entire ARM repeats is indispensable for ELF1 activity. These results suggest that ELF1 ubiquitinates target proteins through an interaction mediated by ARM repeats. Similarities in the phenotypes of elf1 and d61 mutants (mutants of brassinosteroid receptor gene OsBRI1), and in the regulation of ELF1 and OsBRI1 expression, imply that ELF1 functions as a positive regulator of brassinosteroid signaling in rice.     

Light and electron microscopic studies of intramitochondrial bodies in bovine adrenocortical cells by proteolytic digestion

Summary The nature of the intramitochondrial bodies in bovine adrenocortical cells was investigated both light and electron microscopically, by applying enzymatic digestion on paraffin and epon sections. The result that these bodies were extracted completely either by pepsin or by trypsin strengthened the validity of the previous conclusion that their nature is proteinaceous.This work was supported by a Scientific Research Grant, No. 144017, from the Ministry of Education of Japan to Prof. M. Yasuda