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31.
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33.
Growth and death rates of aboveground plant parts were measured in a mature forest and four different-aged deciduous broadleaf forests regeneratede after clear-cutting, with special reference to rates for woody parts (stems and branches) of different diameters (ø) in rerms of the pipe model theory (Shinozaki et al., 1964). The total biomass increment of woody parts of trees higher than 1.3 m varied within a range of 2.1-4.6 ton ha?1 yr?1, the increase beingdue largely to the growth of canopy trees exposed to direct sunlight. Biomass increments of small (ø<1 cm) and medium (1≤ø<5 cm) woody parts were negligibly small except in the youngest forest, and changes in aboveground woody biomass with forest age after clear-cutting mainly resulted from accumulation of large (5 cm<ø) woody parts of canopy trees. Biomass loss of trees due to death and grazing increased with forest age from 4.0 to 8.3 ton ha?1 yr?1. Recovery of leaf and small wood falls was observed at the early stage of regeneration, while large wood falls increased during regeneration. Flower and fruit fall was markedly higher in the mature forest than in the other four forest types. Mortality of woody parts became higher with forest age and was 20, 5.0 and 0.46% yr?1 for small, medium and large parts, respectively, at the mature stage. Aboveground net production of the forest was in therange 7.6-13.3 ton ha?1 yr?1 with the undergrowth vegetation lower than 1.3 m being 0.4-1.4 ton ha?1 yr?1. Production recovered rapidly at an early stage of regeneration and was highest in mature forest. 相似文献
34.
Y Tsukada K Ohkawa N Hibi K Tsuzuki K Oguma H Satoh 《Cancer biochemistry biophysics》1989,10(3):247-256
A monoclonal mouse antibody (MoHG) was produced using in vitro cultured AH66R tumor cells treated with cholesteryl hemisuccinate as an immunogen. The antibody identified a 90 kd membrane glycoprotein (HG-90) which is expressed on in vitro cultured hepatoma cell lines AH66 and AH66R. A monoclonal antibody was prepared to the anthracycline drug daunomycin, and it also reacted with adriamycin. A fusion was made of the hybridoma HG-90 with the hybridoma which recognized daunomycin/adriamycin. This bispecific hybridoma A8C recognized both determinants. We studied the therapeutic effect of the A8C bispecific antibody with adriamycin treatment and compared it to the effect of the bispecific antibody to which adriamycin had been conjugated via an albumin (Alb) bridge. The therapy model used was the tumor AH66R in Donryu rats. Tumor bearing rats had their subcutaneous tumors resected on day 10, a time when distant metastases were present. After the surgical resection of the tumor the rats were injected intravenously for two cycles with the bispecific antibodies, followed by the administration of adriamycin (ADR) or MoHG.Alb.ADR conjugates. A slight therapeutic effect occurred with either MoHG or ADR alone but treatment with the bispecific antibody followed by the administration of ADR or with the MoHG.Alb.ADR conjugates significantly prolonged survival, with 60% of the treated animals being "tumor free" when sacrificed on day 80. Lower serum concentrations of alphafetoprotein were observed with the bispecific antibody and drug treatment. This suggests that the bispecific antibody/drug treatment is potentially more beneficial in the suppression of distant metastases than the MoHG.Alb.ADR conjugate. This may be due to an increase in the local drug concentration of unmodified adriamycin. 相似文献
35.
Pyrolysates of cyanocobalamin, thiamine hydrochloride, riboflavin, pyridoxine hydrochloride, and ascorbic acid were tested for mutagenicity in the histidine-requiring mutants Salmonella typhimurium TA98 and TA100. Each vitamin was sealed in a glass tube and heated at 100-600 degrees C in a muffle furnace. Methanol-chloroform extracts of the pyrolysate of each vitamin tested did not show any mutagenicity in either TA98 or TA100 without rat liver 9000 x g supernatant fraction (S9) added. In the presence of S9, the B-group vitamins (cyanocobalamin, thiamine hydrochloride, riboflavin, and pyridoxine hydrochloride) were all mutagenic in TA98 and TA100, with the highest activity among the vitamins tested found in the pyrolysate of cyanocobalamin. The pyrolysate of 0.25 mumole cyanocobalamin produced 3200 revertants, while the pyrolysates of 0.25 mumole thiamine hydrochloride and riboflavin produced only 910 revertants, and the pyrolysate of pyridoxine hydrochloride did not show any mutagenicity at that amount. The mutagenicity was generally more active to TA98 than to TA100, indicating that frameshift-type mutagens were contained in the pyrolysates. The pyrolysate of ascorbic acid did not show any mutagenic activity in either TA98 or TA100 under the present experimental conditions. 相似文献
36.
37.
Minamisawa Kiwamu; Ogawa Ken-Ichiro; Fukuhara Hideyuki; Koga Jinichiro 《Plant & cell physiology》1996,37(4):449-453
Indole-3-acetaldehyde (IAAId) was detected in the culture supernatantof Bradyrhizobium elkanii. Deuteriumlabelled L-tryptophan (Trp)was incorporated into IAAId and indole-3-acetic acid (IAA),suggesting that B. elkanii produces IAA via IAAId from Trp.In B. elkanii cell suspension, indole-3-pyruvic acid (IPyA)was converted to IAAId, and exogenously added IAAId was rapidlyconverted to IAA. Furthermore, the activity of indolepyruvatedecarboxylase (IPDC), which catalyzes the decarboxylation ofIPyA to produce IAAId and is a key enzyme for IPyA pathway,was detected in B. elkanii cell-free extract. The IPDC activitydepended on Mg2+ and thiamine pyrophosphate, cofactors of decarboxylation.This mounting evidence strongly suggests that IAA synthesisoccurs via IPyA pathway (Trp IPyA p IAAId IAA) in B. elkanii. (Received December 11, 1995; Accepted March 4, 1996) 相似文献
38.
In rodents an intravenous administration of viableCryptococcus (C.) neoformans cells frequently resulted in attachment of intravascular cryptococcal granulomas to inner walls of the large to medium-sized
veins of various organs, including the lungs, liver and spleen. In order to elucidate the pathogenesis of granulomatous changes,
the cells composing the intravascular granulomas were observed by electron microscopic peroxidase (PO) cytochemistry. The
granuloma composing cells could be divided into the following four types according to the pattern of endogenous peroxidase
activity: exudate macrophage (Mφ, type I), PO-negative Mφ (type II), resident Mφ (type III) and other inflammatory cells (type
IV). In the intravenous granulomas of the lung, the percentages of composed cells were 39.0% for type I, 57.9% for type II,
0% for type III and 3.1% for type IV. By contrast, in the interstitial granulomas in the lung, type III Mφs, possibly derived
from alveolar Mφs, played a significant role in granuloma formation. This may indicate that the intravascular granuloma is
almost composed of macrophages derived from monocytes rather than alveolar macrophages. The expression of ICAM-1 on endothelia
of the pulmonary veins was examined by immunoelectron microscopy. An immunogold labeling index was significantly augmented
on the surface of endothelia in response to intravenous challenge ofC. neoformans. The intravascular granuloma demonstrates that the monocytes develop into the granuloma-composing macrophages and suppress
the cryptococcal activities even hi the peripheral blood resulting in an assistance of endothelial functions. 相似文献
39.
The effects of dwarf bamboo,Sasa, cover on the initial morrality of hardwood seedlings were investigated by transplanting 1-year-old beech (Fagus crenata) and current-year oak (Quercus mongolica var.grosseserrata) seedling to three different stands; old-growth beech and secondary oak forests withSasa undergrowth, and aSasa grassland in a grassland-forest series near the top of Mt Jippo, southwestern Japan. The most frequent cause of seedling
morrality was gnawing of the stems by rodents. In the beech forest, the gnawing was more likely to occur underSasa cover, suggesting that it provides a good habitat for rodents on the beech forest floor. TheSasa under growth may thus play an imporrant role in regeneration of beech forest. In the oak floor, mortality of both species
was low and only a little gnawing occurred during a year. However, no natural oak seedling were found in the forest even after
a mast year. This may be because most of the acorns disappeated before establishment. The early-stage demography of hardwood
seedling as oak may thus play an imporrant role in regeneration of oak forest. In theSasa grassland where the seed supply is small, almost all of the seedlings died fromo gnawing regardless of the presence ofSasa cover. These factors prevent the recruitment of a sizable seedling bank. Rodents may thus play an imporrant role in maintenance
of theSasa grassland. 相似文献
40.
It has been proposed that peg formation in the vascular transition region (TR zone) between the hypocotyl and the root in
Cucurbitaceae seedlings is a gravimorphogenetic phenomenon. Initiation of the peg became visible 36 h after imbibition when
cucumber (Cucumis sativus L. cv. Burpee Hybrid II) seeds were germinated in a horizontal position at 24°C in the dark. Simultaneously, sedimented amyloplasts
(putative statoliths) were apparent in the sheath cells surrounding the vascular strands, and in the cortical cells immediately
adjacent to them, in the TR zone. In contrast, the other cortical cells, some of which were destined to develop into the peg,
contained amyloplasts which were not sedimented. These results suggest that the graviperception mechanism for peg formation
may be like that of statoliths in shoot gravitropism. By 48 h following imbibition, the cells of the TR zone still had sedimented
amyloplasts but had lost their sensitivity to gravity, possibly because of their maturation. 相似文献