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排序方式: 共有637条查询结果,搜索用时 15 毫秒
1.
2.
Human axillary secretions influence women''s menstrual cycles: The role of donor extract of females 总被引:3,自引:0,他引:3
George Preti Winnifred Berg Cutler Celso Ramon Garcia George R. Huggins Henry J. Lawley 《Hormones and behavior》1986,20(4):474-482
Menstrual synchrony in human females has previously been demonstrated among women attending a predominantly female university as well as among women attending coeducational universities. In each of these studies, women who spent the most time together were most likely to show the menstrual synchrony. In this experiment, the possibility that substances in axillary secretions might mediate this effect was tested using a prospective, double-blind research design and a combined axillary extract from a group of female donors. Female subjects who reported themselves to have normal (29.5 +/- 3 day) cycles were exposed to the axillary extracts or blank/ethanol for 10 to 13 weeks. Recipients of the axillary extracts showed a significant reduction in "days' difference in menses onset" relative to the donor cycle, no change was evident for recipients of blank/ethanol. These results demonstrate that constituents from the axillary region of donor females can shift the time of menstrual onset of another group to conform with the donors' cycle and that this effect can occur even in the absence of social contact. 相似文献
3.
4.
Sediment-related growth limitation of Elodea nuttallii as indicated by a fertilization experiment 总被引:4,自引:0,他引:4
1. A fertilization experiment was performed to identify the limiting nutrient for the growth of submerged vegetation in ditches of a peat-grassland system in the Netherlands, in which restoration measures involved ceasing fertilization, exporting nutrients by removal of above-ground plant mass and large-scale introduction of calcium-rich, nutrient-poor artesian water.
2. Growth of Elodea was significantly enhanced by enrichment with nitrogen alone, and by fertilization with nitrogen in combination with phosphorus, and by nitrogen in combination with phosphorus and potassium.
3. Plant tissue nutrient concentrations increased significantly, for nitrogen by enrichment with nitrogen alone, and with nitrogen in combination with phosphorus and potassium; for phosphorus by enrichment with phosphorus alone and with phosphorus in combination with nitrogen and potassium; tissue concentrations of potassium were not enhanced by any treatment.
4. The elemental ratios of treated plants indicated that nitrogen, rather than phosphorus, was limiting in all treatments, except in those involving nitrogen and NK enrichment (when phosphorus was limiting).
5. The efficiency with which plants used nutrients declined with increased supply of nitrogen and phosphorus, but was unchanged when potassium was increased. Efficiencies were similar to those of other aquatic macrophytes. 相似文献
2. Growth of Elodea was significantly enhanced by enrichment with nitrogen alone, and by fertilization with nitrogen in combination with phosphorus, and by nitrogen in combination with phosphorus and potassium.
3. Plant tissue nutrient concentrations increased significantly, for nitrogen by enrichment with nitrogen alone, and with nitrogen in combination with phosphorus and potassium; for phosphorus by enrichment with phosphorus alone and with phosphorus in combination with nitrogen and potassium; tissue concentrations of potassium were not enhanced by any treatment.
4. The elemental ratios of treated plants indicated that nitrogen, rather than phosphorus, was limiting in all treatments, except in those involving nitrogen and NK enrichment (when phosphorus was limiting).
5. The efficiency with which plants used nutrients declined with increased supply of nitrogen and phosphorus, but was unchanged when potassium was increased. Efficiencies were similar to those of other aquatic macrophytes. 相似文献
5.
Manuel R. Chavarri Noriyoshi Yamakita Shirley Chiou Celso E. Gomez-Sanchez 《The Journal of steroid biochemistry and molecular biology》1993,45(6):493-500
Aldosterone production occurs in the outer area of the adrenal cortex, the zona glomerulosa. The glucocortocoids cortisol and corticosterone, depending upon the species, are synthesized in the inner cortex, the zona fasciculata. Calf zona glomerulosa cells rapidly lose the ability to synthesize aldosterone when placed in primary culture unless they are incubated in the presence of the antioxidants butylated hydroxyanisol and selenous acid, the radioprotectant DMSO, and the cytochrome P-450 inhibitor metyrapone. In the presence of these additives, calf zona fasciculata cells in primary culture synthesize aldosterone at rates which can approach those from cells isolated from the zona glomerulosa. Calf zona glomerulosa and fasciculata cells both responded well to ACTH and angiotensin II, but the zona fasciculata cells respond very poorly compared to glomerulosa cells to increased potassium in the media. Rat zona fasciculata cells in primary culture under similar conditions did not synthesize aldesterone, suggesting that the regulation of the expression of the enzymes responsible for the biosynthesis of aldosterone in the two species is different. Two distinct cytochrome P-450 cDNAs which hydroxylate deoxycorticosterone at the 11β position have been described in the rat, human and mouse. Both cytochrome P-450 cDNAs have been cloned and expressed in non-steroidogenic cells, but only one is expressed in the zona glomerulosa and only this glomerulosa cytochrome P450 can further hydroxylate deoxycorticosterone to generate aldosterone. Two bovine adrenal cDNAs have been described with 11β-hydroxylase activity and their expression products in transiently transfected COS cells can convert deoxycorticosterone into aldosterone. Both enzymes are expressed in all zones of the adrenal cortex. Zonal regulation of aldosterone synthesis in the bovine adrenal gland may be due to an 11β-hydroxylase with aldosterone synthesizing capacity which has not yet been isolated. Alternatively, a single enzyme might be responsible for the several hydroxylations in the pathway between deoxycorticosterone and aldosterone and zonal synthesis might be controlled by unknown factors regulating the expression of C-18 hydroxylation. The incubation of zona fasciculata with antioxidants and metyrapone results in atypical expression of this activity by an unclear mechanism. 相似文献
6.
Alex Graça Contato Vanessa Kaplum Débora Botura Scariot Francielle Pelegrin Garcia Hugo Falzirolli Fábio Vandresen Tânia Ueda-Nakamura Sueli de Oliveira Silva Cleuza Conceição da Silva Celso Vataru Nakamura 《化学与生物多样性》2023,20(7):e202300523
Leishmaniasis is a tropical zoonotic disease. It is found in 98 countries, with an estimated 1.3 million people being affected annually. During the life cycle, the Leishmania parasite alternates between promastigote and amastigote forms. The first line treatment for leishmaniasis are the pentavalent antimonials, such as N-methylglucamine antimoniate (Glucantime®) and sodium stibogluconate (Pentostam®). These drugs are commonly related to be associated with dangerous side effects such as cardiotoxicity, nephrotoxicity, hepatotoxicity, and pancreatitis. Considering these aspects, this work aimed to obtain a new series of limonene-acylthiosemicarbazides hybrids as an alternative for the treatment of leishmaniasis. For this, promastigotes, axenic amastigotes, and intracellular amastigotes of Leishmania amazonensis were used in the antiproliferative assay; J774-A1 macrophages for the cytotoxicity assay; and electron microscopy techniques were performed to analyze the morphology and ultrastructure of parasites. ATZ−S-04 compound showed the best result in both tests. Its IC50, in promastigotes, axenic amastigotes and intracellular amastigotes was 0.35±0.08 μM, 0.49±0.06 μM, and 15.90±2.88 μM, respectively. Cytotoxicity assay determined a CC50 of 16.10±1.76 μM for the same compound. By electron microscopy, it was observed that ATZ−S-04 affected mainly the Golgi complex, in addition to morphological changes in promastigote forms of L. amazonensis. 相似文献
7.
E.P.H. BEST H. WOLTMAN & FH.H. JACOBS 《The Plant journal : for cell and molecular biology》2003,36(1):33-44
1. A fertilization experiment was performed to identify the limiting nutrient for the growth of submerged vegetation in ditches of a peat-grassland system in the Netherlands, in which restoration measures involved ceasing fertilization, exporting nutrients by removal of above-ground plant mass and large-scale introduction of calcium-rich, nutrient-poor artesian water.
2. Growth of Elodea was significantly enhanced by enrichment with nitrogen alone, and by fertilization with nitrogen in combination with phosphorus, and by nitrogen in combination with phosphorus and potassium.
3. Plant tissue nutrient concentrations increased significantly, for nitrogen by enrichment with nitrogen alone, and with nitrogen in combination with phosphorus and potassium; for phosphorus by enrichment with phosphorus alone and with phosphorus in combination with nitrogen and potassium; tissue concentrations of potassium were not enhanced by any treatment.
4. The elemental ratios of treated plants indicated that nitrogen, rather than phosphorus, was limiting in all treatments, except in those involving nitrogen and NK enrichment (when phosphorus was limiting).
5. The efficiency with which plants used nutrients declined with increased supply of nitrogen and phosphorus, but was unchanged when potassium was increased. Efficiencies were similar to those of other aquatic macrophytes. 相似文献
2. Growth of Elodea was significantly enhanced by enrichment with nitrogen alone, and by fertilization with nitrogen in combination with phosphorus, and by nitrogen in combination with phosphorus and potassium.
3. Plant tissue nutrient concentrations increased significantly, for nitrogen by enrichment with nitrogen alone, and with nitrogen in combination with phosphorus and potassium; for phosphorus by enrichment with phosphorus alone and with phosphorus in combination with nitrogen and potassium; tissue concentrations of potassium were not enhanced by any treatment.
4. The elemental ratios of treated plants indicated that nitrogen, rather than phosphorus, was limiting in all treatments, except in those involving nitrogen and NK enrichment (when phosphorus was limiting).
5. The efficiency with which plants used nutrients declined with increased supply of nitrogen and phosphorus, but was unchanged when potassium was increased. Efficiencies were similar to those of other aquatic macrophytes. 相似文献
8.
P. Haffter Jörg Odenthal M. C. Mullins Shuo Lin Michael J. Farrell E. Vogelsang F. Haas M. Brand Fredericus J. M. van Eeden Makoto Furutani-Seiki Michael Granato M. Hammerschmidt Carl-Philipp Heisenberg Yun-Jin Jiang D. A. Kane R. N. Kelsh Nancy Hopkins Christiane Nüsslein-Volhard 《Development genes and evolution》1996,206(4):260-276
Mutations causing a visible phenotype in the adult serve as valuable visible genetic markers in multicellular genetic model
organisms such as Drosophila melanogaster, Caenorhabditis elegans and Arabidopsis thaliana. In a large scale screen for mutations affecting early development of the zebrafish, we identified a number of mutations
that are homozygous viable or semiviable. Here we describe viable mutations which produce visible phenotypes in the adult
fish. These predominantly affect the fins and pigmentation, but also the eyes and body length of the adult. A number of dominant
mutations caused visible phenotypes in the adult fish. Mutations in three genes, long fin, another long fin and wanda affected fin formation in the adult. Four mutations were found to cause a dominant reduction of the overall body length in
the adult. The adult pigment pattern was found to be changed by dominant mutations in wanda, asterix, obelix, leopard, salz and pfeffer. Among the recessive mutations producing visible phenotypes in the homozygous adult, a group of mutations that failed to
produce melanin was assayed for tyrosinase activity. Mutations in sandy produced embryos that failed to express tyrosinase activity. These are potentially useful for using tyrosinase as a marker
for the generation of transgenic lines of zebrafish.
Received: 17 June 1996 / Accepted: 15 July 1996 相似文献
9.
Summary A new sterol biotransforming mutant was isolated from NRRL-B3683 Mycobacterium sp. after nitrosoguanidine mutagenesis. The mutant showed an enhanced ability to biotransform stigmasterol into 17-ketosteroids compared with the parental strain. 相似文献
10.
Rebello Celso M.; Ikegami Machiko; Ervin M. Gore; Polk Daniel H.; Jobe Alan H. 《Journal of applied physiology》1997,83(1):213-218
Rebello, Celso M., Machiko Ikegami, M. Gore Ervin, Daniel H. Polk, and Alan H. Jobe. Postnatal lung function and protein permeability after fetal or maternal corticosteroids in preterm lambs.J. Appl. Physiol. 83(1): 213-218, 1997.We evaluated postnatal lung function andintravascular albumin loss to tissues of 123-days-gestation pretermsurfactant-treated and ventilated lambs 15 h after direct fetal(n = 8) or maternal(n = 9) betamethasone treatment orsaline placebo (n = 9). Thebetamethasone-treated groups had similar increases in dynamiccompliances, ventilatory efficiency indexes, and lung volumes relativeto controls (P < 0.05). The lossesof 125I-labeled albumin fromblood, a marker of intravascular integrity, and the recoveries of125I-albumin in muscle and brainwere similar for control and betamethasone-exposed lambs.Betamethasone-treated lambs had lower recoveries of125I-albumin in lung tissues andin alveolar washes than did controls (P < 0.01). Although blood pressureswere higher for the treated groups (P < 0.05), all groups had similar blood volumes, cardiac outputs, andorgan blood flows. Maternal or fetal treatment with betamethasone 15 hbefore preterm delivery equivalently improved postnatal lung function,reduced albumin recoveries in lungs, and increased blood pressures.However, prenatal betamethasone had no effects on the systemicintravascular losses of albumin or did not change blood volumes. 相似文献