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21.
Purification and properties of β-galactosidase from Tilapia intestine: Digestive enzyme of Tilapia-X
ABSTRACT: β-galactosidase of the intestine of Tilapia nilotica was purified by ammonium sulfate precipitation, followed by PAPTG-Sepharose 4B affinity chromatography, ethylenediamineetetraacetic acid ion-exchange chromatography, polyexchanger PBE 94 chromatofocusing, and Sephadex G-100 gel filtration. β-galactosidase was found to be a single band when examined by poly-acrylamide gel electrophoresis. The purifications of β-galactosidase were 27-fold from the crude extract. β-galactosidase showed optimum activity at pH 5.0 at 40°C, and was specifically found to be able to hydrolyze p -nitrophenyl β-galactopyranoside. It degrades galactan and agarose, and produces galactose. β-galactosidase was strongly inhibited by Hg2+ and PCMB. β-galactosidase is considered to be secreted by the upper and middle parts of the intestine and most of the activity was detected in the intestinal juice. 相似文献
22.
Koji?YoshidaEmail author Ryota?Shibasaki Chika?Takami Chisato?Takenaka Kazukiyo?Yamamoto Takafumi?Tezuka 《Journal of Forest Research》2004,9(3):195-203
In order to clarify the chronic influence of acid fog on the gas exchange rates of momi fir (Abies firma Sieb. et Zucc.) trees, we exposed them to simulated acid fog (pH 3) for 3 years. The composition of the acid fog was similar to that observed in a region where momi fir trees have been declining, and it contained organic acids. We then treated the firs with various additional stresses, such as drought, low temperature, fine root cutting, ozone exposure, soil acidification, nitrogen load, and rhizosphere aluminum stress. Under chronic exposure to acid fog, the momi fir seedlings exhibited a pattern of stomatal behavior whereby they excessively opened in summer and closed in winter. Furthermore, the stomata of these seedlings tended to open during drought stress, and their needles were visibly injured after ozone exposure. The net photosynthesis rates of the seedlings exposed to acid fog were regulated by their stomatal aperture, rather than directly by acid fog. These results suggest that acid fog exposure disturbs the control of stomatal function in the momi fir seedlings. In addition, we found that chronic acid fog exposure suppressed the decrease in net photosynthesis rate, due to its nitrogen load. 相似文献
23.
24.
Nobuaki Tamai Chisato Takenaka Shigehiro Ishizuka Takafumi Tezuka 《Journal of Forest Research》2001,6(4):311-313
The relationship between soil air volume and CH4 consumption in brown forest soils was investigated. The CH4 consumption was negatively affected when the soil air volume decreased in experiments carried out bothin situ and in the laboratory. A strong dependence of the CH4 consumption on the soil air volume was found in the laboratory experiment. These results indicate the possibility that the
soil air volume is the primary rate-limiting factor for the CH4 consumption in forest soil. Thus our work suggests that the other factors by which CH4 consumption might be affected should be examined under the same air volume condition in the soil. To obtain accurate data,
we need to be careful not to change the air volume by trampling or disturbing during the measurement of the natural methane
fluxin situ. 相似文献
25.
Variations in the composition of low boiling point (LBP) monoterpenes emitted from needle samples of 150 hinoki (Chamaecyparis obtuse) trees (30 strains, each with five clones) native to Shimane Prefecture, Japan, were investigated using a headspace technique.
The assays revealed considerable proportional variations especially in the amount of sabinene, which ranged from 24% to 78%
of the total LBP monoterpenes. The proportions of α-pinene, myrcene, and limonene negatively correlated with that of sabinene overall. In particular, the proportion of limonene
showed clear negative correlation with that of sabinene (r = −0.98). Differences in the proportion of sabinene among five
clones in each strain were less than 15% in 22 out of 30 strains, indicating that monoterpene composition is constitutively
steady in most strains. In a few strains, however, considerable variation in the composition was observed among clones. 相似文献
26.
Riparian forests greatly influence aquatic ecosystems by providing shade cover, which controls water temperature and limits
primary production. We examined the relationship between forest cover and summer stream temperature in northernmost Japan.
Heat budget and statistical analyses were employed and the results were compared. Heat budget analysis revealed that the water
temperature would decrease almost linearly from 29°C to 25°C with an increase in forested reaches along a 3.2 km stretch of
the river. Multiple regression analysis by the stepwise method chose only open channel length as a variable to explain the
variation in maximum stream temperature. A sharp increase in stream temperature was noted when riparian forest cover was removed
in short lengths, of up to 1.0km; this increasing trend gradually flattened as the length of open stretch increased. Thus,
even small openings in the riparian canopy resulted in drastic rises in summer stream temperature. The maximum summer temperatures
estimated by the two methods were coincided, and can therefore be accurately estimated by regression analysis. Retrospective
analysis based on the regression equation showed that the maximum summer temperature in 1947 was 6°C lower than at present,
and that a sharp increase occurred from 1947 to 1960, a period of rapid expansion of agricultural land development in the
watershed. 相似文献
27.
This article discusses the effect of aluminum on root growth of Querucus serrata Thunb. In a 9-week hydroponics experiment, the effects of various concentrations (0 to 5.0 mM) of Al on root growth were examined. Results revealed that root biomass increases with the increase in Al concentration up to 2.5 mM, and then it tended to decrease. In the next experiment, the effects of H+ and Al3+ on roots were compared in a 4-week hydroponics experiment using three treatment solutions: control (pH 6.0), −Al (without Al, pH 3.5), and +Al (with 2.5 mM Al, pH 3.5). No clear difference in the biomass and root length between the control and −Al treated roots was observed, and root and shoot biomass were increased by Al treatment. These results confirmed that the H+ concentration level, at a pH of 3.5, is not toxic for Q. serrata and the Al-induced increase in root biomass is not caused by the amelioration of H+ toxicity by Al. In the third experiment, roots were exposed to an Al solution (pH 3.6) intermittently. This treatment clarified that Al stimulated rooting and root elongation. In the fourth experiment, the effect of 1 mM Al on root growth during a 15-month period in a sand culture were examined. This experiment confirmed that Al stimulated good growth and development of root systems at appropriate concentrations. Therefore, it is considered that Al-induced root growth enhancement occurs as a long-term and short-term phenomenon. 相似文献
28.
Koji Yoshida Shoko Inaba Chisato Takenaka Takafumi Tezuka 《Journal of Forest Research》2005,10(2):157-161
To clarify the nutrient status in momi fir (Abies firma Sieb. et Zucc.) seedlings under complex stress conditions of acid fog with soil acidification or nitrogen loading, we exposed seedling shoots to simulated acid fog (pH 3) and simultaneously loaded the soil with acid or excess nitrogen for 17 months. Proton and nitrogen loading reduced K concentration in soil, but these treatments had little effect on the nutrient status of fine roots in momi fir seedlings. Acid fog exposure resulted in reduced concentrations of Mg, Al, and Fe in current-year needles and Mg, Al, Cu, Fe, and Zn in 1-year-old needles. The complex effects of acid fog exposure with proton or nitrogen loading on nutrient status were relatively slight. However, elements such as Al and Cu notably reflect the effects of proton loading. These results show that the nutrient status of trace elements, rather than major elements, in needles of momi fir seedlings is sensitive to exposure to acid fog or proton loading. 相似文献
29.
Ryota MATSUYAMA Naotoshi KUNINAGA Tomoya MORIMOTO Tetsuya SHIBANO Akiko SUDO Kazunari SUDO Makoto ASANO Masatsugu SUZUKI Tetsuo ASAI 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2015,77(9):1179-1181
Plesiomonas shigelloides is a causal agent of gastroenteritis, sepsis
and meningitis in humans. We examined the prevalence of P. shigelloides
among great cormorants (Phalacrocorax carbo hanedae) in Japan and the
antimicrobial susceptibility of isolates. P. shigelloides was isolated
from 33 (47.8%) of 69 fecal samples from great cormorants in 2014. All 33 isolates were
subjected to antimicrobial susceptibility testing using broth microdilution methods, which
showed resistance to ampicillin (31 isolates, 93.9%), tetracycline (two isolates, 6.1%)
and trimethoprim (one isolate, 3.0%). The high prevalence of P.
shigelloides in the great cormorants implicates the possible microbiological
risk to public health. 相似文献