Thermal tolerance of a thermally selected strain of rainbow trout <Emphasis Type="Italic">Oncorhynchus mykiss</Emphasis> and the pedigrees of its F1 and F2 generations indicated by their critical thermal maxima

A thermally selected strain of rainbow trout has been established by selective breeding since 1966 in Miyazaki, Japan. In the present study, we compared the critical thermal maxima (CTMs), the temperatures at which organisms reach a predefined sublethal endpoint and lose their equilibrium, between a thermally selected and two normal (Donaldson) strains of rainbow trout. The CTM of one normal strain from Nikko (Nikko strain) acclimated to 20 °C (29.7 °C) was significantly lower than those of the thermally selected strain (30.0 °C) and the other Donaldson strain from Aomori (29.9 °C) (P?<?0.05). The F1 generations, F1T and F1N, were produced by crossing thermally selected strain females with Nikko strain males and Nikko strain females with thermally selected strain males, respectively. No significant difference was observed in the CTM between F1T [30.1?±?0.15 °C (n?=?30)] and F1N [30.1?±?0.16 °C (n?=?30)] (P?>?0.05) for fish acclimated to 20 °C, suggesting that the F1 offspring inherited the thermal tolerance trait from one thermally selected strain parent irrespective of whether it was the male or female. F2 offspring of F1T or F1N also showed the thermal tolerance trait. The coefficients of variation for CTM were also compared among all the datasets obtained in the present study and their values for F1 hybrids were lower than those of the parental generation of the Nikko strain (P?<?0.05). In contrast, the coefficients of variation of F2s were the same as those of their parental generation. Furthermore, the thermally selected strain and Nikko strain as a reference family provide a F2 generation for segregating phenotypes, which is required for in-depth genetic analysis of the thermally selected rainbow trout strain.     

Rice <Emphasis Type="Italic">terpene synthase 18</Emphasis> (<Emphasis Type="Italic">OsTPS18</Emphasis>) encodes a sesquiterpene synthase that produces an antibacterial (<Emphasis Type="Italic">E</Emphasis>)-nerolidol against a bacterial pathogen of rice

Plant volatile compounds, including terpenes, are known to be involved in the rice defense system. In the present analysis of a terpene synthase, OsTPS18, in rice, we found that OsTPS18 was localized in the cytoplasm and synthesized the sesquiterpenes (E)-nerolidol and (E)-β-farnesene. The amounts of (E)-nerolidol and (E)-β-farnesene increased after jasmonic acid (JA) treatment. (E)-Nerolidol had significant antibacterial activity against Xanthomonas oryzae pv. oryzae (Xoo). These results suggest that (E)-nerolidol plays an important role in JA-induced resistance against Xoo and that it functions as an antibacterial compound in rice.     

A bronchopulmonary artery fistula in a horse

A 24-year-old, Thoroughbred gelding presented with difficulty breathing for a few days and intermittent nose bleeding before dying. At necropsy, the bronchoesophageal artery and the bronchial artery that flowed into the left anterior lobe were tortuous and dilated, and it was found that dilated tortuous branches of the bronchial artery ran over the dorsal and ventral surfaces of the left anterior lobe. Histopathologically, an anastomosis between a muscular artery and an elastic artery were demonstrated, which were identified as bronchial and pulmonary arteries, respectively. Based on the gross and histopathological findings, a bronchopulmonary artery fistula was diagnosed. To the best of our knowledge, this is the first case report of a pulmonary vascular anastomosis in a horse.     

Relationship between <Superscript>137</Superscript>Cs concentration and potassium content in stem wood of Japanese cedar (<Emphasis Type="Italic">Cryptomeria japonica</Emphasis>)

To utilize forest resources in areas affected by fallout from the Fukushima Daiichi Nuclear Power Plant accident, it is important to understand the mechanisms of ¹³⁷Cs movement through the stem wood of contaminated trees. Understanding the mechanism of absorption and migration of ¹³⁷Cs to stem wood is necessary for clues to the future prediction of the transition of ¹³⁷Cs to xylem. In the present study, radial variations in ¹³⁷Cs concentration were investigated in Japanese cedar (Cryptomeria japonica D. Don) trees collected 1 year and 10 months after the accident. Additionally, the relationship between ¹³⁷Cs concentration and potassium (K) content was established. Trees with a higher moisture content and lower lightness value in heartwood tended to have a higher ¹³⁷Cs concentration in the heartwood. In these trees, ¹³⁷Cs concentration peaked at the heartwood–sapwood boundary and gradually decreased toward the pith. By contrast, K content within the heartwood remained nearly constant along the radial direction. The heartwood-to-sapwood ratio of ¹³⁷Cs concentration was significantly positively correlated with that of K content. Based on these results, we suggest that ¹³⁷Cs movement from sapwood to heartwood might be related to the K content ratio of heartwood and sapwood.     

Radial and between-family variations of the microfibril angle and the relationships with bending properties in Picea jezoensis families

With emphasis on tree breeding for wood quality in Picea jezoensis, we aimed to evaluate radial and between-family variations in the microfibril angle (MFA) of the S₂ layer in the latewood tracheids in 10 open-pollinated families of 43-year-old P. jezoensis trees. In addition, the relationships between MFA/wood density with the modulus of elasticity (MOE) or modulus of rupture (MOR) were investigated. Significant differences in MFA between families were found from the pith toward the bark. MFA showed higher values around the pith area, although some families showed relatively lower values than others around this area. In addition, due to a larger coefficient of variations of MFA near the pith, the potential for juvenile wood MFA improvement may be greater compared with mature wood. MOE was correlated with MFA in juvenile wood and with wood density in mature wood, whereas MOR was mainly correlated with wood density at radial positions in both woods. Therefore, to improve the MOE and MOR of P. jezoensis wood, both MFA and wood density would be factors to consider in both juvenile and mature woods. On the other hand, there are indications that, only wood density would be an important criterion for improving mature wood properties.     

Molecular identification of `Candidatus Mycoplasma haemovis' in sheep with hemolytic anemia

We examined the presence of hemoplasmas, hemotropic mycoplasmas, among 11 sheep (Ovis aries) with regenerative and hemolytic anemia and found six of them were positive by real-time PCR. The positive samples were then subjected to conventional PCR for direct sequencing of the 16S rRNA gene. Nucleotide sequences of all the positive samples were identified as the 16S rRNA gene of `Candidatus Mycoplasma haemovis' by phylogenetic analysis, demonstrating the infections with this particular hemoplasma species in Japan.     

A Recessive Lesion Mimic Mutant of Rice with Elevated Resistance to Fungal Pathogens

A gamma-ray-induced rice mutant, M1009, which spontaneously forms brown specks on leaves was isolated. In appearance, these lesions very much resemble those that are produced during the hypersensitive resistance response of rice to pathogens. A similar phenotype has been associated with a number of mutants in maize or Arabidopsis, which have been briefly categorized as disease lesion mimics. Brown speck formation was suppressed at temperatures of 25°C and above, and was severe at 20°C. Light irradiation is also required to initiate brown specks. In addition, the mutant exhibits heightened resistance to two major fungal pathogens of rice, Magnaporthe grisea and Cochliobolus miyabeanus. Genetic characterization of the mutant has indicated that its les-bs (lesion-brown speck) phenotype segregates as a monogenic recessive mutation. Received 13 September 1999/ Accepted in revised form 15 December 1999     

Interannual variability in stock abundance of the neon flying squid, Ommastrephes bartramii, in the North Pacific Ocean during 1979–1998: impact of driftnet fishing and oceanographic conditions

Variability in catch-per-unit-effort (CPUE) was examined for the autumn cohort of Ommastrephes bartramii collected with research driftnets during 1979–1998 along five longitudinal transects passing through the Subarctic, Transitional and Subtropical Domains in the North Pacific. CPUE was generally low during the period of intensive commercial driftnet fishing (1980–1992) and increased following the 1992 moratorium on the use of large-scale driftnets. However, CPUE levels were low for the cohorts hatched in 1992 and 1996 (captured in subsequent years owing to a one-year life of O. bartramii ) that experienced low sea surface temperatures from hatching to recruitment. Among similar-aged squid collected from 180° and 179°30'W in June, mantle lengths were significantly greater in 1997 than during 1995–96. These findings suggest that the driftnet fishery and sea surface temperatures from hatching to recruitment strongly affected stock abundance and possibly growth.