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SUSUMU Y. TAKAHASHI 《Development, growth & differentiation》1971,13(3):131-139
As a preliminary to the study of the mode of action of juvenile hormone using the left colleterial gland of the cockroach, properties of the glucoside synthetase of protocatechuic acid were studied. For this purpose, a convenient assay method of phenolic glucoside synthetase (UDPG-phenol glucosyl transferase) was devised. The method is based on the determination of labeled protocatechuic acid glucoside which is synthesized from uridine diphosphate 14C-glucose and protocatechuic acid. The optimal pH for the glucoside synthetase reaction is 6.5. The enzyme activity is localized in a particulate fraction of fat body tissues and is partly found in the soluble fraction, presumably liberated during the course of centrifugation. In the female cockroach, the enzyme activity is distributed mainly in the fat body. Chemical analyses revealed that the reaction product is 4-O-β-D-glucoside of protocatechuic acid. The homogenate of fat body tissues can synthesize glucosides from UDPG and various phenols, such as O-aminophenol, p-nitrophenol and hydroquinone, as well as natural O-diphenols. 相似文献
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David S. Smith 《The Journal of cell biology》1966,29(3):449-459
The organization of intersegmental muscle fibers associated with the dorsal abdominal sclerites of the cockroach is described. These fibers correspond closely, in the disposition and derivation of the membranes of the transverse tubular system and sarcoplasmic reticulum cisternae, with insect synchronous flight muscle fibers, but differ markedly from these in their fibrillar architecture and mitochondrial content. The mitochondria are small and generally aligned alongside the prominent I bands of the sarcomere, and, in the best-oriented profiles of the A bands, thick filaments are associated with orbitals of twelve thin filaments, a configuration that has also been observed in striated fibers of insect visceral muscle. These structural features of insect muscles are compared and discussed in terms of possible variations in the control of contraction and relaxation, and in the nature of their mechanical role. 相似文献
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本实验用地塞米松造成大鼠垂体促皮质激素细胞及其靶腺肾上腺皮质束状带细胞分泌抑制,对这两种细胞中的溶酶体及分泌自噬和自体吞噬活动进行了超微结构观察、CMP 酶细胞化学定性和形态计量。实验结果显示,在分泌受抑制状态下,垂体促皮质激素细胞中分泌自噬和自体吞噬作用加强,与此同时,肾上腺皮质细胞中自体吞噬作用也业著加强。这些结果表明,在分泌类固醇激素的细胞中,溶酶体以自体吞噬的方式清除一部分生产激素的细胞器,可能是一种普遍存在的分泌调节机制,正如在分泌蛋白质和肽类激素的细胞中普遍存在着分泌自噬这一调节机制一样。 相似文献
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W. J. V. Osterhout 《The Journal of general physiology》1930,14(2):285-300
It is suggested that K enters chiefly as KOH, whose thermodynamic potential (proportional to the ionic activity product (a
K) (a
OH)) is greater outside than within. As this difference is maintained by the production of acid in the cell K continues to enter, and reaches a greater concentration inside than outside. KOH combines with a weak organic acid which is exchanged for HCl entering from the sea water (or its anion is exchanged for Cl-), so that KCl accumulates in the sap. Na enters more slowly and its internal concentration remains below that of K. The facts indicate that penetration is chiefly in molecular form. As the system is not in equilibrium the suggestion is not susceptible of thermodynamic proof but it is useful in predicting the behavior of K, Na, and NH4. 相似文献
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The -amylase induced by helminthosporol and gibberellic acidin the embryo-less endosperm of barley was separated into thethree fractions, 1, 2 and 3, by DEAE-cellulose column chromatography.A maximum amount of the 2. was induced by gibberellic acid andthat of the as by helminthosporol. After rechromatography, the2 induced by gibberellic acid and the as induced by helminthosporolshowed their respective single bands in an electrophoresis agargel zymogram. On the other hand, the ai induced by helminthosporoland gibberellic acid showed three bands. Dihydrohelminthosporic acid, a derivative of helminthosporol,induced the same isozymes as helminthosporol did. (Received May 8, 1967; ) 相似文献
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Lu Gao Kejian Peng Yan Xia Guiping Wang Liyuan Niu Chunlan Lian 《International journal of phytoremediation》2013,15(4):307-319
Phytolacca americana L. can accumulate large amounts of heavy metals in its aerial tissues, especially cadmium (Cd) and manganese (Mn). It has great potential for use in phytoextraction of metals from multi-metal-contaminated soils. This study was conducted to further investigate the Cd- and Mn-tolerance strategies of this plant. Concentrations of non-protein thiols (NPTs) and phytochelatins (PCs) in leaves and roots increased significantly as the concentration of Cd in solution increased. The molar ratios of PCs:soluble Cd ranged from 1.8 to 3.6 in roots and 8.1 to 31.6 in leaves, suggesting that the cellular response involving PC synthesis was sufficient to complex Cd ions in the cytosol, especially that of leaves. In contrast, excess Mn treatments did not result in a significant increase in NPT or PC concentrations in leaves or roots. Oxalic acid concentrations in leaves of plants exposed to 2 or 20 mM Mn reached 69.4 to 89.3 mg (0.771 to 0.992 mmol) g–1 dry weight, respectively, which was approximately 3.7- to 8.6-fold higher than the Mn level in the 0.6 M HCl extract. Thus, oxalic acid may play an important role in the detoxification of Mn. 相似文献
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Abstract— β- N -Oxalyl- l -α,β-diaminopropionic acid (ODAP), the toxin isolated from the seeds of Luthyrus sativus produces head retraction, tremors and convulsions when injected into a variety of experimental animals. In 12-day-old rats, it has been found that the convulsive behaviour is accompanied by profound biochemical changes in the brain. The brain homogenates prepared from ODAP injected animals show a higher rate of respiration. There is a decrease in the brain glucose, glycogen, ATP, phosphocreatine and acetylcholine levels of the convulsing animals. The inorganic phosphate, lactic acid and acetylcholineesterase levels increase. These results establish that ODAP is a typical convulsant. 相似文献
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REGULATION OF FATTY ACID COMPOSITION BY IRRADIANCE LEVEL IN THE EUSTIGMATOPHYTE NANNOCHLOROPSIS SP.1
Chemical composition and quantitative cytological measurements were determined for the eustigmatophyte Nannochloropsis sp. Cultures were grown in turbidostats at three irradiance levels: growth-limiting light, growth-saturating light and photoinhibiting light. Cellular chlorophyll a content decreased as irradiance level increased, concomitant with a disproportionate reduction in carotenoid content. Nannochloropsis sp. grown in saturating light was characterized by a high content of lipid, fatty acids and carbohydrate compared with cells grown in light-limiting conditions. The increase in cellular lipid content coincided with a reduction in the percentage of eicosapentaenoic acid (C20:5) and arachidonic acid (C20:4), fatty acids that are mainly associated with galactolipids, and with an increase in the relative abundance of palmitic acid (C16:0) and palmitoleic acid (C16:1). At growth limiting light conditions, Nannochloropsis sp. preferentially synthesized galactolipids; however, as growth became light saturated, relatively more neutral lipids, mainly triacylglycerols, were synthesized. Changes in lipid content and composition were qualitatively related to changes in cell morphology. Cells grown under low light conditions were characterized by a large relative volume of chloroplast, high surface density of thylakoid membranes and low relative volume of lipid storage bodies. The physiological implications of the changes in cellular lipid composition and ultrastructure are discussed in relation to light/shade adaptation. 相似文献
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C. W. Sullivan 《Journal of phycology》1977,13(1):86-91
Synchronized populations of Navicula pelliculosa (Bréb.) Hilse show a 10-fold increase in Si(OH)4 transport rate during traverse through the cell division cycle. The transport activity pattern is similar to a “peak enzyme.” Kinetic analysis showed there was a significant change in Ks values, indicating increased “affinity” for Si(OH)4 as cells neared maximal uptake rates. However, the dramatic changes in transport rate at various cell cycle stages were also reflected by alterations in the Vmax, values of the transport process, suggesting a change in the number of functional transport “sites” in the plasma membrane. Cells in the wall forming stage, arrested from further development by Si(OH)4 deprivation, maintained high transport rates for as long as 7 h. The rates decreased rapidly if protein synthesis were blocked or if Si(OH)4 was added, the latter allowing the cells to traverse the rest of the cycle. The half-life of the transport activity ranged from 1.0 to 2.2 h when protein synthesis was inhibited at various cell cycle stages and during the natural decline of activity late in the cycle. The transport system appears to be metabolically unstable as is typical for a “peak protein.” The rise in transport rate through the cell cycle did not depend on the presence of Si(OH)4 in the medium; therefore, the transport system does not appear to be induced by its substrate. The rise in transport is also observed in L:D synchronized cells developing in the presence of Si(OH)4; neither does the transport system appear to be derepressed. The transport rate was strongly cell cycle-stage dependent; the data appeared to fit the “dependent pathway” model proposed by Hart-well to explain oscillations in enzyme synthesis during the cell cycle. 相似文献
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G. F. Wooten D. M. Jacobowitz J. M. Saavedra J. Axelrod 《Journal of neurochemistry》1975,24(6):1107-1110
Abstract— Superior cervical ganglionectomy results in a complete noradrenergic neuronal denervation of the rat sublingual-submaxillary salivary gland. Dopamine-β-hydroxylase activity in the serous submaxillary gland falls approximately 90% after noradrenergic denervation; but in the mucinproducing sublingual gland dopamine-β-hydroxylase activity is reduced by only 33%. Dopamine-β-hydroxylase immunofluorescence in the submaxillary gland is distributed with noradrenergic neurons and is eliminated by superior cervical ganglionectomy. In the sublingual gland dopamine-β-hydroxylase immunofluorescence is localized within mucinous acini and small ducts, and the disposition and intensity of staining materials is not affected by noradrenergic denervation for up to 30 days. DBH protein in the sublingual gland had little physiologic activity in vivo. Low levels of authentic dopamine-β-hydroxylase activity were detected in saliva. Thus, dopamine-β-hydroxylase protein is present in the sublingual gland in an extraneuronal location and appears to be a secretory product of the gland. 相似文献
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Abstract— β- N -Oxalyl- l -α, β-diaminopropionic acid (ODAP), the Lathyrus sativus neurotoxin can be detected in significant concentrations in the synaptosomal fractions isolated from young rat brain and adult monkey spinal cord, when these animals manifest neurological symptoms after ODAP administration. However, isolated synaptosomes fail to exhibit any transport system for ODAP uptake. ODAP administered in vivo appears to get localized in a population of synaptosomes which exhibit a high affinity uptake system for glutamate. 相似文献
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1. Twenty-five solutions which contained KCl (0.0, 0.2, 0.4, 0.6, and 0.8 gm. per liter), in combination with CaCl2 (0.0, 0.2, 0.4, 0.6, and 0.8 gm. per liter), 10.0 gm. of NaCl, and 0.2 gm. of NaHCO3 per liter of solution were tested in order to determine satisfactory KCl/CaCl2 ratios in an insect physiological salt mixture for the maintenance of muscular activity by the isolated crop of the American roach. Satisfactory activity products (0.390 to 0.549) were obtained in seven mixtures with KCl/CaCl2 ratios of 0.2/0.2, 0.4/0.4, 0.6/0.6, 0.8/0.8, 0.2/0.4, 0.4/0.6, and 0.6/0.8, expressed as gram per liter. These ratios lie between 0.50 and 1.00. In solutions which contained calcium, but no potassium, approximately 50 per cent of the crops exhibited an initial tone increase and were arrested in rigor. See Fig. 2. In solutions which contained potassium, but no calcium, all crops showed an initial loss of tone and arrest in relaxation. See Fig. 2. 2. Seven KCl/CaCl2 ratios (see paragraph 1 above) were tested with eight NaCl concentrations (1.0, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, and 1.8 per cent) at a pH of 8.0. In these mixtures, the ones with KCl/CaCl2 ratios of less than 1.0 produced higher activity products than those with ratios equal to 1.00. The highest average activity product (0.849) was obtained in the solutions with 0.2 gm. of KCl and 0.4 gm. of CaCl2 per liter. 3. Four KCl/CaCl2 ratios (0.2/0.2, 0.4/0.4, 0.2/0.4, and 0.4/0.6 gm. per liter) were tested with 1.4, 1.5, and 1.6 per cent NaCl at a pH of 7.5. When analyzed with data from comparable solutions at a pH of 8.0, it was found that 1.4 per cent NaCl afforded an optimum environment for isolated crop activity. 4. Effects of hydrogen and hydroxyl ion concentrations were studied at pH values of 6.8, 7.5, 8.0, and 8.9. The highest average activity product, 1.011, was produced at a pH of about 8.0. 5. A satisfactory physiological salt solution for the isolated foregut of the American roach, Periplaneta americana, would contain 14.0 gm. of NaCl, 0.4 gm. of CaCl2, 0.2 gm. of KCl, and 0.2 gm. of NaHCO3 per liter of solution. This mixture should have a pH value between 7.8 and 8.2. 6. Durations of crop activity extending over periods as long as 25 hours were quite common, and several crops maintained contractions for more than 30 hours. The greatest longevity was for crop 814, from a female, which continued activity for slightly more than 47 hours. 7. A significant difference between the activity products of the crops from males and the crops from females was recorded. Although there was not a significant difference in the amount of food ingested by males and females, 12 hours after feeding there was more food in the females'' crops, and the food progressed more rapidly through the males'' crops than through the females''. In addition, crops from the two sexes reacted differently to the effects of day old solutions. This sex difference is apparently related to an inherently increased activity of the crop from the male roach. 相似文献
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S. L. N. Rao 《Journal of neurochemistry》1978,30(6):1467-1470
Abstract— A comparative study of the tissue disposition of the L. sativus neurotoxin has been done using [3 H]0DAP with special reference to the CNS in normal and Diamox treated (acidotic) adult rhesus monkeys and also in the day old chick, a species susceptible to the neurotoxin, and the adult rat which is refractory to it. The neurotoxin was detected in the CNS of the acidotic monkey and also in the normal monkey in nearly the same quantity. The neurotoxin was largely localised in the lumbosacral region of the spinal cord. The amount of radioactive ODAP in the CNS following its intraperitoneal injection was twice that seen following its intravenous injection.
The concentrations of the neurotoxin 90 min after injection in the CNS of the adult rat and the day old chick were almost the same and increased 2 fold by 24 h. No radioactive metabolite of ODAP could be detected in either the tissues or the urine of the different species. Species (and age) differences in susceptibility to the L. sativus neurotoxin is thus independent of its entry into the CNS. 相似文献
The concentrations of the neurotoxin 90 min after injection in the CNS of the adult rat and the day old chick were almost the same and increased 2 fold by 24 h. No radioactive metabolite of ODAP could be detected in either the tissues or the urine of the different species. Species (and age) differences in susceptibility to the L. sativus neurotoxin is thus independent of its entry into the CNS. 相似文献
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Abstract— The isomeric phenolic acids, homovanillic acid (4-hydroxy,3-methoxyphenylacetic acid) and homo-iso-vanillic acid (3-hydroxy,4-methoxyphenylacetic acid), were separated and identified by means of paper chromatography of their azo-derivatives with diazotized para-nitroaniline. Using this chromatographic procedure, homo-iso-vaniliic acid was identified in several samples of human cerebrospinal fluid, an observation which suggests that dopamine may be partly metabolized in brain, with the production of 4-methoxy derivatives. 相似文献