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51.
Norma P. Stimler 《Analytical biochemistry》1984,142(1):103-108
The capacity of lung explant cultures to synthesize collagen can be estimated by determining the content of [3H]hydroxyproline in protein following incubation with [3H]proline. The technique requires acid hydrolysis followed by quantitative separation of hydroxyproline from proline for scintillation counting and is often restricted to methods that can accommodate large samples because of relatively low specific radioactivity. A method which is useful for such samples, providing rapid separation of nonderivatized amino acids by ion-exchange HPLC, is described here. The HPLC system employs an HPX-87C cation-exchange column in 10 mm calcium acetate, pH 5.5, at 85°C. Under isocratic conditions hydroxyproline is completely resolved from proline with quantitative recovery of the 3H cpm applied to the column. Large amounts of material, equivalent to at least 150 mg wet wt of lung, can be applied without affecting resolution or recovery, and samples can be injected at intervals as short as 40 min. This method was used to study collagen biosynthesis in a model of pulmonary fibrosis induced in rabbits by the tumor-promoting agent, phorbol myristate acetate (PMA), and provides information concerning total protein synthesis as well as production of collagen. The data show a doubling in the rate of collagen production in lung explants prepared from animals treated with PMA compared with explants from control animals. 相似文献
52.
Effects of medium growth regulator composition and embryo size on shoot organogenesis of callus derived from globular- to torpedo-shaped zygotic embryos of five sunflower (Helianthus annuus L.) genotypes were examined. Forty growth regulator combinations composed of 0 to 5 mgl-1 naphthaleneacetic acid (NAA) and 0 to 1 mgl-1 6-benzylaminopurine (BA) were tested. The frequency of zygotic embryos forming shoot-regenerating callus was analysed according to categorical data modelling using a maximum-likelihood approach. Both NAA and BA must be present to induce the formation of morphogenic callus from zygotic embryos, but each growth regulator effect varied with the genotype. For four genotypes, NAA and BA effects were neither linear nor quadratic; whereas, they were linear for the fifth one. Most effective concentrations across genotypes were 0.1 mgl-1 NAA and 0.5 mgl-1 or 0.2 mgl-1 BA. However, the optimal growth regulator combination depended on the genotype and an interaction between the two growth regulators. The frequency of shoot-regenerating callus also varied with the size of the embryo explant. For all five genotypes, 0.4 to 1.2 mm long heart-shaped zygotic embryos formed morphogenic callus more frequently than smaller less-developed ones. 相似文献
53.
54.
55.
The regeneration of meristematic tissues from sporophytes of Laminaria digitata was studied by protoplast and tissue culture. Sequential treatment of explants in sterile seawater with 1% Betadine for 5 min,
1% commercial bleach for 1–2 min and 2% antibiotic treatment supplemented with 1 μM GeO2 overnight enabled viable explants as high as 55%. Different morphogenetic responses were observed from tissue culture on
media supplemented with plant growth regulators alone or in combination, mainly filamentous calluses up to 50% according to
the media. Dark green compact calluses were observed on two combinations: 4 μM Pi + 2 μM N-(2-chloro-4-pyridyl)-N’-phenylurea
(CPPU) and 0.04 μM Pi + 0.44 μM 6-benzylaminopurine. Thalloid-like structures comparable to adventitious buds were regenerated
on medium supplemented with 4 μM Pi + 0.45 μM zeatin but at low frequency suggesting a strong genotypic effect. Friable calluses
were developed from protoplasts in enriched medium with polyamines and containing 0.40 μM CPPU + 0.45 μM 2,4-dichlorophenoxyacetic
acid. In order to produce protoplasts, a one-step enzymatic protocol was developed and yields reached 22 × 106 protoplasts per gram of fresh weight. 相似文献
56.
Summary This study reports a protocol for high-efficiency plant regeneration from leaf explants of male Himalayan poplar (Populus ciliata Wall.). Shoots were regenerated at high frequencies from explants grown on Murashige and Skoog (MS) medium supplemented with
0.5 mg l−1 kinetin and 0.2 mg l−1 indole-3-acetic acid (IAA). Regenerated shoots developed roots in MS medium supplemented with 0.1 mg l−1 IAA. Himalayan poplar plantlets could be produced within 2 mo. after acclimatization in a sterile mixture of sand and soil. 相似文献
57.
Simple strategy for the in vitro conservation of Ipsea malabarica an endemic and endangered orchid of the Western Ghats of Kerala,India 总被引:2,自引:0,他引:2
A simple protocol was developed for plantlet regeneration from seedling leaf segments of pigeonpea cultivar ICPL 93115 through shoot organogenesis. Ten-day-old seedlings aseptically grown on MS medium were used for furnishing leaf segments. Initial incubation for 5 days in dark at 25±2 °C followed by transfer to 10/14-h light / dark cycle (12.1 mol photons m–2 s–1) favoured regeneration. The decisive role of 6-benzyl adenine at different concentrations was established on shoot organogenesis. Murashige and Skoog's (MS) (1962) medium fortified with BA of 5.0 mg l–1 was optimum for shoot regeneration and MS + BA of 1.0 mg l–1 for shoot elongation, while MS + IAA (1.0 mg l–1) + kinetin (0.1 mg l–1) showed good results for rooting. 相似文献
58.
Changes in the accumulation of flavonoid and isoflavonoid conjugates associated with plant age and nodulation in alfalfa (Medicago sativa) 总被引:1,自引:0,他引:1
Carbohydrate and mineral nutrition was studied in relation to abscission in fruitlets from leafy inflorescences of the Washington navel orange ( Citrus sinensis [L.] Osbeck). Differences in the growth rate of the fruitlets permitted to predict abscission several weeks in advance. This allowed characterization of early differences in composition and behaviour of persisting and abscising fruitlets.
Inflorescences with persisting fruitlets accumulated more mineral elements than inflorescences with abscising fruitlets, and for the phloem-mobile elements the excess accumulation was allocated to the fruitlets. Starch accumulated in the inflorescence leaves during early fruitlet growth, and this accumulation was enhanced by the persisting fruitlets despite their higher growth rate and mobilizing ability. The relations between the fruitlets and the inflorescence leaves cannot be explained totally in terms of source sink relationships; a hormonal regulation of the leaves by the fruitlets is postulated.
Acid invertase activities and hexose concentration in the pericarp were higher in the abscising fruitlets. The lower early growth rate of these fruitlets is thus not caused by a limitation in carbohydrate supply. It seems more related to carbohydrate utilization, probably hormonally mediated, as demonstrated by the higher dependence on hormone supply for the growth in vitro of the endocarp explants. 相似文献
Inflorescences with persisting fruitlets accumulated more mineral elements than inflorescences with abscising fruitlets, and for the phloem-mobile elements the excess accumulation was allocated to the fruitlets. Starch accumulated in the inflorescence leaves during early fruitlet growth, and this accumulation was enhanced by the persisting fruitlets despite their higher growth rate and mobilizing ability. The relations between the fruitlets and the inflorescence leaves cannot be explained totally in terms of source sink relationships; a hormonal regulation of the leaves by the fruitlets is postulated.
Acid invertase activities and hexose concentration in the pericarp were higher in the abscising fruitlets. The lower early growth rate of these fruitlets is thus not caused by a limitation in carbohydrate supply. It seems more related to carbohydrate utilization, probably hormonally mediated, as demonstrated by the higher dependence on hormone supply for the growth in vitro of the endocarp explants. 相似文献
59.
Jahanara Begum-Hasan Mary Senterman Peter Gillett Charlotte Laplante Branchaud Beverley E. Pearson Murphy 《In vitro cellular & developmental biology. Animal》1993,29(6):505-511
Summary Fetal bovine serum (FBS) is frequently used to supplement chemically defined media such as Ham’s F10 when studying placental
explant cultures. However in vitro production of hormones is usually declining by the 2nd or 3rd day and is short-lived (7
to 10 days). In this study we explored the use of human maternal serum (HMS) from early gestation as the medium supplement
to Ham’s F10. Early placental hormone production was compared using two concentrations of FBS and HMS. On Day 3 of incubation,
progesterone production in 10% HMS was 12-fold increased over that in 10% FBS, estradiol production was increased 10-fold,
and βhCG production more than 3-fold. When the serum concentrations were increased to 40%, the results in all cases were similar
to those at 10%. Preliminary characterization studies revealed that the stimulatory activity of HMS is heat-labile, neither
extractable into organic solvent (diethyl ether) nor dialyzable, suggesting that it is protein in nature. In a long-term incubation,
compared with FBS (7 days), HMS permitted survival of culture up to 30 days, judged both histologically and biochemically.
We conclude that HMS provides substance(s), probably protein in nature, not present in FBS or non-pregnant human serum, which
are important for human placental viability and function in vivo. 相似文献
60.
Explants taken from the leaves of yams (Dioscorea bulbifera L.) at different stages of development were cultured in vitro on a checkerboard using various combinations and/or concentrations of auxin (2,4-d) and cytokinin (6-BAP). An addition of cytokinin to the culture media was not essential for callus induction from explants derived from young leaves in the very early stages of expansion. When the leaves expanded further they required cytokinin and the requirement increased considerably during expansion. Explants taken from fully expanded leaves were no longer able to proliferate, even when extremely high concentrations of cytokinins were applied. Callus grown from highly immature leaves was able to continue proliferating in the absence of cytokinin when subcultured. Callus, that initially required cytokinin in the medium, proliferated in the absence of exogenous cytokinin when subcultured.Abbreviations 2,4-d
2,4-dichlorophenoxyacetic acid
- 6-BAP
6-benzylamino purine
- 1-NAA
1-naphthalenacetic acid 相似文献