Enzymatic hydrolysis of wood with alkaline treatment

Pulverized samples of wood, cedar and eucalyptus were treated with 5 N NaOH solutions at 25–150 °C. Hemicellulose and lignin content in the samples decreased with increasing treatment temperatures, while the recovery of glucose was maintained at nearly 90 %. X-ray diffraction analysis showed that the content of the original cellulose I structure in the samples decreased with increasing temperature, and most of the cellulose in the sample treated at 150 °C was converted to cellulose II by mercerization. Enzymatic hydrolysis of the alkaline-treated samples was carried out at 37 °C using solutions comprising a mixture of cellulase and β-glucosidase. The samples treated at higher temperatures showed better enzymatic degradability. Treatment with an alkaline solution of lower concentration (1 N NaOH) at 150 °C was also used. Despite significant quantities of hemicellulose and lignin being removed, mercerization was not induced. The enzymatic degradability was much lower than that of the sample treated with a 5 N NaOH solution at 150 °C. Thus, treatment with concentrated alkaline solution at high temperature led to not only the removal of hemicellulose and lignin, but also to modification of the cellulose structure, which resulted in high efficiency of enzymatic saccharification of the wood samples.     

Ray florets color and shape mutants induced by C ion beam irradiation in chrysanthemum

Ion beam irradiation is attracting attention in floriculture as a means of inducing mutations. We investigated the effect of ion beam irradiation on induction of ray florets color/shape mutants from two strains of chrysanthemum to create new flower cultivars. The ray florets and leaf explants of chrysanthemum cultivars, ‘Shiroyamate’ and ‘H13’, respectively, cultured on MS medium were irradiated with ¹²C⁵⁺ ion beam at doses of 1, 2, 4 and 8Gy. The frequency of shoot primordia formation on ray florets explants of ‘Shiroyamate’ and shoot bud formation on leaf explants of ‘H13’ was decreased by 8Gy and 4Gy irradiation, respectively. The effective dose of ion beam was less than 4Gy in ‘Shiroyamate’ and less than 2Gy in ‘H13’. After exposure to an effective dose of ion beam, regenerated plants were grown in a green-house and the field. Yellow ray florets mutants from ‘Shiroyamate’, and various ray florets color mutants (dark-red, light red, pink, pink spray) and a flower shape mutant (double-ray florets) from ‘H13’ were induced by ion beam irradiation. Furthermore, a white mutant was obtained from a chimeric mutant. These results suggest that the combination of ion beam irradiation and tissue culture would be an effective means of generation mutants at a high efficiency.     

Population model of Rana japonica crossing agricultural concrete canals: evaluating population conservation by improving the migration routes of frogs

Agricultural canals with deep concrete walls are commonly installed in paddy field areas following land consolidation projects in Japan. Such canals create a critical migration barrier for frogs, as escape is not possible after falling in. Hence, countermeasures that allow migrating frogs to cross agricultural canals, such as lid structures to prevent frogs from falling in or the creation of partial slopes to allow escape, have been developed to conserve endangered frog populations. The objective of this study was to design a method for evaluating the population viability of the endangered Japanese Brown Frog, Rana japonica, following the implementation of countermeasures. Two types of model simulations were examined: (1) a ??basic model,?? based on an age-structured model and (2) a ??crossing model,?? to evaluate migrating frogs crossing canals. Parameters, such as survival rate and fecundity, were estimated from field observation data of age-dependent population fluctuations. Comparison of a basic model simulation with the field observation data suggests model validation. The crossing model simulation, which had an initial population of 1,000 individuals, showed that a crossing proportion of greater than 30?C40% would achieve 95% population viability after 5?years. The simulation also showed that a crossing proportion of over 80% would also achieve 95% population viability after 40?years. These results indicate that frog survival during the migration period is insured, as long as no additional countermeasures are necessary after installation.     

Yellowtail neuropeptide Y: molecular cloning,tissue distribution,and response to fasting

Neuropeptide Y (NPY) and cholecystokinin (CCK) play important roles in regulating appetite in vertebrates, including mammals and fish. Understanding the appetite mechanism is important in aquaculture to improve production performance. The yellowtail Seriola quinqueradiata is one of the most cultured fish in Japan, but little is known about its appetite hormones. In the present study, complementary DNA encoding for NPY was cloned in yellowtail and consists of 604 bp, in which deduced amino acid sequences show high identity to those of other teleosts. In tissue distribution, the npy and cck mRNAs were detected in all examined tissues (whole brain, telencephalon, optic tectum, hypothalamus, cerebellum, pituitary, retina, stomach, pyloric caeca, anterior intestine, liver, and kidney). In the fasting experiment, only npy mRNA expression in the hypothalamus responded to fasting, showing a significantly high value compared with that in control fish. The expression of cck mRNA in the examined tissues did not change with fasting. The npy mRNA expression in the hypothalamus might be involved in feeding regulation in yellowtail.     

Monitoring by real-time PCR of three water-borne zoosporic Pythium species in potted flower and tomato greenhouses under hydroponic culture systems

The high-temperature-tolerant Pythium species P. aphanidermatum, P. helicoides, and P. myriotylum cause serious diseases in many crops under hydroponic culture systems in Japan. Control of the diseases is difficult because these zoosporic pathogens spread quickly. In this study, a real-time PCR method was developed for monitoring the spread of zoospores of the three pathogens. Specific primers and TaqMan probes were established using the internal transcribed spacer regions of the rDNA. Specificity was confirmed using known isolates of each species and closely related non-target species. The sensitivity of DNA detection was 10 f. for each pathogen. 10 f. DNA corresponded to 4 P. aphanidermatum, 3 P. myriotylum, and 4 P. helicoides zoospores, respectively. Therefore, this real-time PCR method was used to evaluate and monitor zoospores in the nutrient solutions of ebb-and-flow irrigation systems for potted flower production and closed hydroponic culture systems for tomato production. The results indicated that the pathogens were present in the hydroponic culture systems throughout the year, and spread before disease occurrence.     

Identification of QTLs controlling harvest time and fruit skin color in Japanese pear (Pyrus pyrifolia Nakai)

Using an F₁ population from a cross between Japanese pear (Pyrus pyrifolia Nakai) cultivars ‘Akiakari’ and ‘Taihaku’, we performed quantitative trait locus (QTL) analysis of seven fruit traits (harvest time, fruit skin color, flesh firmness, fruit weight, acid content, total soluble solids content, and preharvest fruit drop). The constructed simple sequence repeat-based genetic linkage map of ‘Akiakari’ consisted of 208 loci and spanned 799 cM; that of ‘Taihaku’ consisted of 275 loci and spanned 1039 cM. Out of significant QTLs, two QTLs for harvest time, one for fruit skin color, and one for flesh firmness were stably detected in two successive years. The QTLs for harvest time were located at the bottom of linkage group (LG) Tai3 (nearest marker: BGA35) and at the top of LG Tai15 (nearest markers: PPACS2 and MEST050), in good accordance with results of genome-wide association study. The PPACS2 gene, a member of the ACC synthase gene family, may control harvest time, preharvest fruit drop, and fruit storage potential. One major QTL associated with fruit skin color was identified at the top of LG 8. QTLs identified in this study would be useful for marker-assisted selection in Japanese pear breeding programs.     

Influence of temperature and feeding regimes on growth and notochord deformity in reared <Emphasis Type="Italic">Anguilla japonica</Emphasis> leptocephali

The high mortality rate of reared Japanese eel Anguilla japonica larvae is largely due to lower growth rate and the higher rate of deformed larvae. To establish an effective rearing protocol for this species, we examined the effects of water temperature and feeding regimes on their growth and notochord kyphosis. Larvae at 165 days post hatching were reared for 28 days at mean temperatures of 24, 25 and 27 °C, and were fed 4 or 6 times per day. Larval growth rate was significantly higher in larvae reared at 24–25 °C and fed 6 times per day. However, growth rate was significantly reduced at 27 °C, suggesting a shortage of metabolic energy due to an elevated cost of the higher basal metabolic rate at higher temperatures and low nutritional performance of currently used artificial diet. Notochord kyphosis was promoted by elevated water temperature, and two-way ANOVA showed that water temperature and feeding frequency had combined effects on the deformity. These findings suggest the importance of concurrently manipulating both environmental and nutritional factors to produce healthy eel larvae in captivity.     

Effects of temperature,zoospore concentration,infection period,and fruit maturity on <Emphasis Type="Italic">Phytophthora palmivora</Emphasis> infection of figs

White powdery rot in figs caused by Phytophthora palmivora is an important disease resulting in severe fruit rot, but is not currently effectively controlled in Japan due to a lack of understanding of its epidemiology. Therefore, the effects of temperature, zoospore concentration, infection period, and fruit maturity on infection of figs were examined by inoculating the fruit with a suspension of P. palmivora zoospores. The zoospores germinated at temperatures from 5 to 35 °C, with the optimum temperature range being 20–35 °C. Germ tube length in zoospore cysts was greatest at 20–30 °C. The disease developed in green figs at temperatures from 20 to 30 °C. Figs inoculated with as few as 10 zoospores per fruit developed severe symptoms at the optimum temperature (25 °C). The minimum infection period required for infection was 2 h at 20–28 °C. All of the figs developed symptoms within an 8 h infection period at 25 or 28 °C, and with a 6 h infection period at 25 °C. All fruit at different stages of development (immature fruit, yellow fruit, and mature fruit) developed symptoms. These results indicate that P. palmivora is capable of infecting figs over a wide range of temperatures, within a short infection period, at a low concentration of zoospores, and at any stage of development. These data could be used to construct forecasting models and develop effective control systems for white powdery rot.     

Growth pattern and seasonal weight changes of the feral raccoon (Procyon lotor) in Hokkaido,Japan

The growth pattern and seasonal weight fluctuations of feral raccoons in Hokkaido were evaluated between 1999 and 2001. The growth rates inbody length and body weight were described for juveniles (young of the year) and yearlings (animals born in the previous season) using the Gompertz growth model. The asymptotic body sizes for males were greater than those for females. Young raccoons born during spring in the study area could potentially grow up to their asymptotic size at the beginning of their first winter, but they would not reach their full adult sizes until at least their second fall. Adult raccoons (animals > or = 2 -year-old) had seasonal weight fluctuations with annual weight loss of 25% to 28% of mean maximum weights in west-central Hokkaido, but these result would be an underestimate of the degree of annual weight fluctuations. Juvenile raccoons can be distinguished from the older animals by measuring body length or body weight during fall in Hokkaido.