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71.
An immunohistochemical and immunoelectron microscopic study was used to demonstrate tyrosine hydroxylase (TH) and dopamine -hydroxylase (DBH) immunoreactivities in the rat pancreas. Small TH immunoreactive cells were found in close contact with large TH immunonegative ganglion cells among the exocrine glands and were occasionally found in some islets. Some of these TH immunoreactive cells were also DBH immunopositive. The immunoreaction product was seen diffusely in the cytoplasm and in the granule cores of TH immunoreactive cells. All intra-pancreatic ganglion cells were immunoreactive for DBH, but not for TH. The TH immunoreactive cells were identified as small intensely fluorescent (SIF) cells due to their localization and morphological characteristics and showed no insulin, glucagon, somatostatin or pancreatic polypeptide immunoreactivities. These results indicate that SIF cells may release dopamine or noradrenaline to adequate stimuli while the intra-pancreatic ganglion cells with only DBH may not synthesize catecholamines in a normal biosynthetic pathway. TH immunoreactive nerve bundles without varicosities and fibers with varicosities, associated or unassociated with blood vessels, were found in both the exocrine and endocrine pancreas. Close apposition of TH immunoreactive nerve fibers to the smooth muscle and endothelial cells of the blood vessels was observed. A close apposition between TH immunoreactive nerve fibers and exocrine acinar cells and islet endocrine cells was sometimes found in the pancreas. The immunoreaction product was seen diffusely in the axoplasm and in the granular vesicles of the immunoreactive nerve fibers. Since no TH immunoreactive ganglion cells were present in the rat pancreas, the present study suggests that noradrenergic nerve fibers in the pancreas may be extrinsic in origin, and may exert an effect on the regulation of blood flow and on the secretory acitivity of the acinar cells, duct cells and endocrine cells. 相似文献
72.
The food habits of the Iriomote catFelis iriomotensis were studied by analyzing 177 feces collected monthly from 1987 to 1988. A total of 26 food items were identified. The frequency
of lizards and frogs in the feces was higher than those of mammals and birds. The food habits changed greatly seasonally.Eumeces skinks were fed on most frequently, and found in the feces with a similar high frequency occurrence in March–April and July–September,
while their proportion to the total number of food items was larger in March–April than in July–September. The cats fed on
larg-sized skinks, adultEumeces kishinouyei, more in March–April than in other seasons. The number of skinks sighted in the course of a road census was greater from
March to August, and large-sized skinks were sighted more in March–April than in July–August. The cats fed selectively on
large-sized skinks in every season. Therefore, changes in the food habits depended on the food availability. Characteristics
of food habits in the Iriomote cat are discussed in comparison with the food habits of other felids in temperate and tropical
regions. 相似文献
73.
Toshiya Masumoto 《Ecological Research》1994,9(2):159-165
Field observations on the relationship between male mating success and emergence timing in the funnel-web spider,Agelena limbata, were conducted.Agelena limbata is an annual species and adult males appear slightly earlier than adult females in July. As males deposit a copulatory plug
at the female epigynum after copulation, copulation with virgin females is important to males. The number of copulations in
males with virgin females, which strongly correlates with the longevity of males and the number of females that males courted,
did not correlate with the emergence timing of males. Early emerged males and females were significantly larger in size than
later ones, but the correlation coefficient between the emerged date and the cephalothorax width was not strong. Males that
emerged earlier did not have any advantage in copulating with larger and more fecund females. Furthermore, virgin females
first copulated on average 7.9 days after their final molt and the mortality rate of adult males increased after the final
molt. These factors may favor the smaller degree of protandry in male emergence timing inA. limbata. 相似文献
74.
Axillary bud flowering after apical decapitation in Pharbitis in relation to photoinduction 总被引:2,自引:0,他引:2
Michiyuki Ono Kimiyo Sage Ono Koichiro Yamada Masaru Yasui Mitsuo Okazaki 《Physiologia plantarum》1993,87(1):1-6
The flowering response of axillary buds of seedlings of Pharbitis nil Choisy, cv. Violet, was examined in relation to the timing of apical bud removal (plumule including the first leaf or second leaf) before or after a flower-inductive 16-h dark period. When the apical bud was removed well before the dark period, flower buds formed on the axillary shoots that subsequently developed, but when removed just before, or after, the dark period, different results were observed depending on the timing of the apical bud removal and plant age. In the case of 8-day-old seedlings, fewer flower buds formed on the axillary shoots developing from the cotyledonary node when plumules were removed 20 to 0 h before the dark period. When the apical bud was removed after the dark period, no flower buds formed. Using 14-day-old seedlings a similar reduction of flowering response was observed on the axillary shoots developing from the first leaf node when the apical bud was removed just after the dark period. To further elucidate the relationship between apical dominance and flowering, kinetin or IAA was applied to axillary buds or the cut site where the apical bud was located. Both chemicals influenced flowering, probably by modulating apical dominance which normally forces axillary buds to be dormant. 相似文献
75.
Expression of the [beta]-Glucuronidase Gene in Pollen of Lily (Lilium longiflorum), Tobacco (Nicotiana tabacum), Nicotiana rustica,and Peony (Paeonia lactiflora) by Particle Bombardment 总被引:1,自引:0,他引:1
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A [beta]-glucuronidase (GUS) gene that is under the control of the anther-specific LAT52 promoter of tomato (Lycopersicon esculentum) and the nopaline synthetase polyadenylation terminator was successfully expressed in pollen of Lilium longiflorum, Nicotiana tabacum, Nicotiana rustica, and Paeonia lactiflora using a pneumatic particle gun. The GUS gene in plasmid pBI221 was also expressed, to a lesser extent, in pollen of all of these species. The presence of methanol in the substrate solution for histochemical GUS assay and the incubation time in this solution influenced successful detection of GUS expression in bombarded pollen. Cytological analysis of GUS-expressing pollen of lily showed that introduced gold particles were seen in intracellular compartments of pollen, including the vegetative cytoplasm, vegetative nucleus, and generative cytoplasm. 相似文献
76.
Aplopsora corni sp. nov. is proposed for a rust fungus whose uredinial and basidial stage occurs onCornus controversa (Cornaceae) in Hokkaido. This new species is separated by its larger urediniospores and probasidia from the morphologically
closely relatedA. nyssae onNyssa aquatica andN. sylvatica (Cornaceae) distributed in southern North America. 相似文献
77.
Mitsuo Matsuda Toshiya Nosaka Masaaki Sato Norio Ohshima 《European journal of applied physiology and occupational physiology》1993,66(2):122-126
To evaluate the effects of exercise on aortic wall elasticity and elastic components, young male rats underwent various exercise regimes for 16 weeks. In the exercised rats, the aortic incremental elastic modulus decreased significantly when under physiological strain. The aortic content of elastin increased significantly and the calcium content of elastin decreased significantly in the exercised group. The accumulated data from the exercised and sedentary groups revealed that the elastin calcium content was related positively to the incremental elastic modulus. We concluded that physical exercise from an early age decreases the calcium deposit in aortic wall elastin and that this effect probably produced in the exercised rats a distensible aorta. 相似文献
78.
To determine whether lipid-secreting cells have cytosolic Ca2+ concentration ([Ca2+]c)-related secretory mechanisms, morphological changes and intracellular calcium dynamics of Harderian glands of guinea pigs stimulated by secretagogs were studied by electron microspy and Fura-2/AM digital image analysis. Control glandular cells contained large lipid vacuoles that were bordered by multi-layered membranes. Rough-surfaced endoplasmic reticulum, mitochondria, and smooth-surfaced endoplasmic reticulum may be involved in lipid vacuole formation. Myoepithelial cells surrounded alveoli. After carbamylcholine (CCh, 10–6, 10–5, and 10–3 M) stimulation, lipid materials within the membranous structures were frequently discharged by an exocytotic mechanism. Conspicuous deformation of glandular cells caused by vigorous contraction of myoepithelial cells was observed in isolated alveoli after 10–6M CCh stimulation, whereas the deformaties of glandular tissues perfused via vessels were small even after 10–3M CCh stimulation. Connective tissue between glandular alveoli inhibited unbridled myoepithelial-cell contraction. Fura-2/AM digital imaging analysis revealed that CCh stimulation caused an increase in [Ca2+]c in isolated alveoli. The morphological reactions and changes in [Ca2+]c were prevented by atropine. When extracellular calcium ions were absent, enhanced extrusion of lipid vacuoles, myoepithelial-cell contraction, and a rise in [Ca2+]c after CCh stimulation were not observed. Nicotine and catecholamines had no effect on the secretion or on the dynamics of [Ca2+]c. It can be concluded that acetylcholine elicits exocytosis in glandular cells and contraction of the myoepithelial cells of Harderian glands, accompanied by an increase in [Ca2+]c. The dynamics of [Ca2+]c of the gland alveoli are mostly dependent on extracellular Ca2+. 相似文献
79.
We investigated how the distribution pattern of eggs and larval on the host plant, Turritus glabra, was influenced by the oviposition behavior of the pierid butterfly Anthocharis scolymus. Females searched for the host plants visually and they frequently approached taller host plants with sparse surrounding vegetation. After encountering host plants, oviposition behavior of females was independent of host plant characteristics such as height, density, and type of surrounding vegetation. A female laid eggs singly on a host plants. Most females appeared to lay their eggs regardless of the presense of eggs on the host plant. Consequently egg and larva tended to be abundant on conspicuous host plants as measured by height or relative isolation from other plants. However, overcrowding of eggs on an individual host decreased the survival rate of larvae. 相似文献
80.
Yoshihiro Izumi Kanji Ono Masayuki Takamiya Kiichi Fukui 《Journal of plant research》1993,106(4):319-325
Using cultured cells of the hornwortAnthoceros punctatus, the change in the relative chloroplast DNA content in each stage of chloroplast division was investigated to clarify the
relationship between the division cycle of a chloroplast and a cell nucleus. Samples of cultured cells were stained with 4′,6-diamidino-2-phenylindole
(DAPI) and then observed with an epifluorescence microscope and a chromosome image analyzing system (CHIAS). A chloropiast
in cultured cells duplicated DNA with an increase in size. When a chloroplast began to divide, it was constricted in the middle,
taking a dumbbell shape, and then divided into two daughter chloroplasts. In cultured cells of this species, the pattern of
quantitative change of chloroplast DNA, that is, the DNA replication pattern of chloroplasts, corresponded to that of cell
nuclear DNA in mitosis. 相似文献