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1.
To accumulate histological information of cetaceans, the proper gastric gland of Minke whales was examined by light and electron microscopic observation. A small number of mucous neck cells and a large number of chief and parietal cells were observed in the gland. At the body to basal portions of the gland, the ratio of chief cells to other cells seemed to be large compared to the neck portion. Transmission electron microscopy revealed that the chief cell had secretory granules with middle level of electron density, and that the parietal cell contained abundant mitochondria and intracellular canaliculi. The proper gastric gland of the Minke whales may appear to secrete large amounts of digestive enzymes and have high digestive activity.  相似文献   
2.
Fennel, a seed of Foeniculum vulgare, is used as a culinary spice and traditional medicine. The methanolic extract of fennel showed a characteristic of mechanism-based inactivation on erythromycin N-demethylation mediated by human liver microsomal cytochrome P450 3A4 (CYP3A4). The present study was conducted to identify the fennel constituent having the inhibition. Thirteen compounds have been isolated from a methanol extract of fennel and tested for their inhibition on CYP3A4. Among them, 5-methoxypsoralen (5-MOP) showed the strongest inhibition with an IC50 value of 18.3 microM and a mixed type of inhibition. In addition, with the preincubation time of 20 min only 5-MOP showed preincubation time dependency; the IC50 value decreased from 18.3 microM with a preincubation time of 0 min to 4.6 microM with a preincubation time of 20 min. Further investigation on 5-MOP showed the characteristics of time-dependent inhibition, requirement of NADPH, lack of protecting effect of nucleophiles, and recovery of CYP3A4 activity by the competitive inhibitor. This result suggests that the inhibitory activity of CYP3A4 by 5-MOP was a mechanism-based inactivation. The kinetic parameter for mechanism-based inactivation was characterized by a KI value of 15.0 microM and a kinact value of 0.098 min(-1).  相似文献   
3.
The repeated elements called phytomers, which consist of leaf, node, internode and axillary bud, play an important role in the development of modular organization in plants. Rice has the striking feature that the rate of the phytomer production is closely synchronized with the rate of leaf emergence (phyllochron). We examined developmental changes of phyllochron by using 10 near-isogenic lines (NILs) showing diversified growth durations in rice. The NILs were established by backcrosses with a strain practically insensitive to photoperiod, and they consisted of early- or late-flowering NILs whose differences of growth duration were caused by the combinations of alleles at 6 loci. The developmental patterns of phyllochron were evaluated by means of a quartic polynomial, which fitted well in most cases. The results indicated that phyllochron greatly changed during development, especially in late-flowering NILs as well as the recurrent parents, although the fluctuation of phyllochron was not so marked in the early-flowering NILs. Thus, the developmental change of phyllochron was highly dependent upon the genotypes and/or growth duration; however, it was associated with neither floral initiation nor temperature, indicating that the change of phyllochron might reflect internal or physiological changes which occur during the life cycle of rice. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   
4.
Carcinogenicity and chronic toxicity of para-dichlorobenzene (p-DCB) were examined by exposing 50 BDF1 mice and 50 F344 rats of both sexes by inhalation to p-DCB vapor at a target concentration of 0 (control), 20, 75 or 300 ppm for 6 hr/day, 5 days/week and 2 years. Incidences of hepatocellular carcinomas, hepatoblastomas and hepatic histiocytic sarcomas in the 300 ppm-exposed male mice, and hepatocellular adenomas and carcinomas and hepatoblastomas in the 300 ppm-exposed female mice were increased. An increase in the incidences of most of those liver tumors was dose-related. No increase in tumor incidence was found in any p-DCB-exposed rat of either sex. Centrilobular hypertrophy of hepatocytes and papillary mineralization and pelvic urothelial hyperplasia of the kidney were noted in the 300 ppm-exposed male rats. Treatment- and age-related increases in incidences of the eosinophilic globules of the respiratory and olfactory epithelia in female rats and incidences of the respiratory metaplasia of the nasal gland epithelium in mice and rats and the olfactory epithelium in mice were noted. The nasal lesion was the most sensitive endpoint of chronic inhalation toxicity. Induction of the mouse hepatocarcinogenicity and lack of the rat nephrocarcinogenicity found in the present study were compared with the mouse liver tumors and the rat renal tumors reported by the NTP gavage study, and discussed in light of the estimated p-DCB uptake into the body through the inhalation and the oral administration.  相似文献   
5.
The spatial distribution of Antarctic minke whales in the Ross Sea with relation to spatial distributions of their prey – krill – was investigated in this study using generalized additive models (GAMs). Spatial distributions of two species of krill (ice and Antarctic krill) were estimated by GAMs. Three abiotic factors – distance from the continental shelf break (800 m isobaths), the mean temperature and salinity from the surface to 200 m (MTEM‐200 and MSAL‐200), and latitude and longitude – were used as covariates for models of krill. Estimated spatial distributions of krill were then used with other covariates to model the spatial distribution of Antarctic minke whales. In the selected model of Antarctic minke whales, Antarctic krill were more influential than ice krill. The number of Antarctic minke whales increased as the density of Antarctic krill increased to around 1.5 g m?2. Beyond that, the number of Antarctic minke whales decreased as the density of Antarctic krill increased. High densities of the Antarctic minke whales were estimated along the sea ice edge in the eastern part of the Ross Sea. Specifically, the densities were high in the north of the continental shelf break where low MTEM‐200 and MSAL‐200 and intermediate densities of Antarctic krill were observed. Further data collection is needed to investigate interannual variations and trends in their relationship. The results show that the spatial distribution of Antarctic minke whales is a function of longitude, distance from the shelf break, oceanographic condition (temperature and salinity), and densities of ice and Antarctic krill.  相似文献   
6.
罗勒在盐胁迫条件下水分生理及精油含量的变化   总被引:3,自引:0,他引:3  
本研究旨在寻找增加芳香植物罗勒(Ocimum basiicum L)的次生代谢产物(精油)的有效途径,对罗勒生长过程中制造一种盐分压力的环境胁迫的手段进行了尝试性研究。用本研究设计的高浓度的复合盐配方处理的结果表明虽然在盐分胁迫下的罗勒水势降低,气孔阻力加大,蒸腾速度减弱,但没有对罗勒的生物量产生大的影响,相反却提高了精油含有率。  相似文献   
7.
Monosaccharides released by acid hydrolysis from paddy field soil, from the light and the heavy fraction of soil, front some plant fragment were determined using automated anio-exchange chromatography.

Between 5 and 12 per cent of the organic carbon was present as saccharides.

The monosaccharide composition of the different soils was very similar, in spite of differences in the absolute amount of saccharides present. The amount of the various monosaccharide in the whole soil was found to be in the order glucose»xylose galactose, mannose, arabinose rhamnose ribose.

The monoccharide composition of the soils showed a marked contrast to that of the rice ra8ment, and partially decomposed plant remains taken from the soil. Glucose, xylose, arabi-the predominant saccharides in the rice fragments and the plant remains, while the amounts of galactose, mannose, rhamnose were negligibly small.

It was found that the proportion of galactose, mannose, rhamnose and ribose in the heavy fraction Of soil was greater than that of glucose, xylose, and arabinose

The present observation was in agreement with the view that soil sauharides comprised Pentoses originates in plant materials.

The molar ratio of xylose to mannose was calculated to show the characteristics of the mono-saccharide composition of soils and some plant muerials.  相似文献   
8.
An Hand von Bodenproben aus langjährigen Dauerdüngungsversuchen im Relsfeld wurden Untersuchungen über den Einfluβ der Kalkdüngung auf den Humusgehalt, die Humuszusammensetzung und den Koblenhydratgehalt durchgeführt, die folgende Ergebnisse brachten:

Durch langjährige hobe Kalkdüngung wurde der Gehalt an organischer Bodensubstanz wesentlich herabgesetzt und dies um so stärker, je höher die Kalkmenge war, wobei die Erhöhung der pH-Werte parallel verlief. Aber bel der Kalkdüngung im praktisch angewandten Ausmaβe oder im etwas höheren Ausmaβe wurde der Gehalt an organischer Bodensubstanz unwesentlich verändert, obwohl es sich auch hler urn elne sebr langjährige Dauerdüngung handelt.

Die langjährige hohe Kalkdüngung verändert sowohl den extrahierbaren Humusgehalt als auch die Humuszusammensetzung stark, wobei extrahierte Fulvosäure besonders stark abgenommen hat und der relative Fulvosäureanteil am Gesamthumus beträchtlich kleiner wurde.

Eine absolute und relative Abnahme der Menge an gesamten und wasser-löslichen Kohtenhydraten wurde durch langjährige hohe Kalkdüngung festgeetellt.

Es wird darauf hingewiesen, daβ die Kohlenhydrate in stärkerer Beziehung zu den Bestandteilen der Fulvosäure als zu denen der Huminsäure stehen.

Der Einfluβ organischer Düngung zur Erhaltung der unter Kalkdüngung stehenden organischen Bodensubstanz wurde festgestellt.  相似文献   
9.
10.
Paratuberculosis (Ptb), caused by Mycobacterium avium subsp. paratuberculosis (Map), is a chronic enteritis that affects many ruminants and other wild animals worldwide. Ptb is a great concern in animal health and in etiology of human Crohn's disease (CD). In the present study, we detected Map-specific insertion sequence IS900 of DNA in tissue sections surgically removed from lesions of patients with CD (29 samples), ulcerative colitis (UC) (17 samples), and non-inflammatory bowel disease (IBD) (20 samples). We then compared the histopathological findings of 29 CD and 17 UC cases with those of 35 cases of bovine Ptb, since few comparative pathological studies of human IBD and Ptb have been conducted. The QPCR examination indicated positive results in 13.37% of CD cases, 3.57% of UC cases, and 10% of non-IBD cases. Human CD tissues typically exhibited destructive full thickness enteritis with severe lympho-plasma infiltration and scattered additional granulomas; UC lesions exhibited much less inflammation than CD lesions. Non-IBD control samples did not exhibit pathological changes. Human CD and UC lesions were very different from Ptb lesions that are characterized by predominant granuloma formation. Immunohistochemistry for Map antigen and acid-fast staining were negative in all human IBD cases but were always positive in Ptb cases. Our present comparative study strongly suggests that we reconsider the previous hypothesis that "Map infection" causes CD, even though human intestines were considered to have been exposed to the Map antigen containing the DNA.  相似文献   
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