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Jacek Kęsy Beata Maciejewska Magdalena Sowa Magdalena Szumilak Krzysztof Kawałowski Maja Borzuchowska Jan Kopcewicz 《Plant Growth Regulation》2008,55(1):43-50
It has been shown that both IAA and ethylene application inhibit flower induction in the short-day plant Pharbitis nil. However application of IAA has elevated ethylene production in this plant, as well. Strong enhancement of ethylene production
is also correlated with the night-break effect, which completely inhibits flowering. In order to determine what the role of
IAA and ethylene is in the photoperiodic flower induction in Pharbitis nil, we measured changes in their levels during inductive and non-inductive photoperiods, and the effects of ethylene biosynthesis
and action inhibitors on inhibition of flowering by IAA. Our results have shown that the inhibitory effect of IAA on Pharbitis nil flowering is not physiological but is connected with its effect on ethylene biosynthesis. 相似文献
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Unexposed blanks prepared from Kodak AR 10 stripping film were dried by 3 methods: (1) fast, open drying with a fan for 25 min, (2) slow drying in a desiccator for 6 hr, and (3) very slow drying in a desiccator for 24 hr. The number of background grains depended on the mode of drying. Fast drying (method 1) gave 0.7 grain per 100 μ2, slow drying (method 2) gave 0.33 grain; very slow drying (method 3), only 0.17 grain. The increase of background after fast drying is assumed to be caused by the rapid shrinkage of wet emulsion. This causes an increase in the intraemulsion pressure which, in turn, sensitizes the silver bromide crystals to cause an increase in the number of developable grains. 相似文献
6.
We have examined whether low temperature, as a pervasive thermodynamicstimulus, is sensed independently in different parts of thecell by studying low temperature responses of phosphoproteinsin isolated nuclei. The isolated alfalfa (Medicago saliva) nucleirespond to cold by rapid and reversible changes in phosphorylationlevel of their proteins. The population of such cold-regulatedphosphoproteins and the cold-stimulation of their phosphorylationare greater in a freezing-tolerant cultivar Apica than in asensitive cultivar Trek. With a 4-day cold treatment of theseedlings, additional proteins showing cold-stimulated phosphorylationappear in the nucleus of Apica while there is little changein the case of Trek. Furthermore, nuclei from cold-treated seedlingsof Apica, but not of Trek, show a large accumulation of heat-stableproteins. These results support the view that the low temperaturesensing and acclimation occur in all vital parts of the celland that accumulation of heat-stable nuclear proteins may berelated to freezing tolerance. (Received October 14, 1996; Accepted November 11, 1996) 相似文献
7.
Submitochondrial localization and function of alkaline inorganic pyrophosphatase in maize seedlings.
Alkaline inorganic pyrophosphatase and Mg-ATPase are localized within the mitoplast of maize seeding mitochondria. NaF inhibited the PPase activity, whereas oligomycin and dicyclohexylcarbodiimide inhibited the Mg-ATPase activity. The mitoplast preparation synthesized PPi from Pi under conditions excluding hydrolysis of endogenous ATP. PPi synthesis was inhibited by ADP, antimycin A, NaCN and 2,4- dinitrophenol but not by oligomycin. It is suggested that PPi synthesis in the maize seedling mitochondria proceeds at the expense of the energy of electron transport chain and is independent of the ATP synthesis. 相似文献
8.
Biocontrol of Listeria monocytogenes on Fresh-Cut Produce by Treatment with Lytic Bacteriophages and a Bacteriocin 下载免费PDF全文
Britta Leverentz William S. Conway Mary J. Camp Wojciech J. Janisiewicz Tamuna Abuladze Ming Yang Robert Saftner Alexander Sulakvelidze 《Applied microbiology》2003,69(8):4519-4526
The fresh-cut produce industry has been the fastest-growing portion of the food retail market during the past 10 years, providing consumers with convenient and nutritious food. However, fresh-cut fruits and vegetables raise food safety concerns, because exposed tissue may be colonized more easily by pathogenic bacteria than intact produce. This is due to the higher availability of nutrients on cut surfaces and the greater potential for contamination because of the increased amount of handling. We found that applied Listeria monocytogenes populations survived and increased only slightly on fresh-cut Red Delicious apples stored at 10°C but increased significantly on fresh-cut honeydew melons stored at 10°C over 7 days. In addition, we examined the effect of lytic, L. monocytogenes-specific phages via two phage application methods, spraying and pipetting, on L. monocytogenes populations in artificially contaminated fresh-cut melons and apples. The phage mixture reduced L. monocytogenes populations by 2.0 to 4.6 log units over the control on honeydew melons. On apples, the reduction was below 0.4 log units. In combination with nisin (a bacteriocin), the phage mixture reduced L. monocytogenes populations by up to 5.7 log units on honeydew melon slices and by up to 2.3 log units on apple slices compared to the control. Nisin alone reduced L. monocytogenes populations by up to 3.2 log units on honeydew melon slices and by up to 2.0 log units on apple slices compared to the control. The phage titer was stable on melon slices, but declined rapidly on apple slices. The spray application of the phage and phage plus nisin reduced the bacterial numbers at least as much as the pipette application. The effectiveness of the phage treatment also depended on the initial concentration of L. monocytogenes. 相似文献
9.
S. Vijayaraghavan T. Srinivasaraghavan S. Musti S. Kar T. Swaminathan A. Baradarajan 《Bioprocess and biosystems engineering》1995,12(5):227-229
The toxic effects of phenol, a common constituent of many industrial effluents, necessitates treatment of the polluted streams. Biodegradation is a popular technique and enjoys many advantages. The degradation of phenol with Arthrobacter species is studied in batch cultures and it is observed that the substrate is inhibiting. The fit of various models, including the model proposed earlier by us [17], to the experimental data is studied. The model is used to fit available data in literature, which unfortunately is very sparse. In all the cases the present model fits the data best.List of Symbols
S mg/l
substrate concentration
-
S
0 mg/l
threshold substrate concentration
-
K
I
mg/l
inhibition constant
-
K
m
, K
s
mg/l
half saturation constant of growth kinetics
-
m, n
constants
-
1/h
specific growth rate
-
m
1/h
maximal specific growth rate
-
X mg/l
biomass concentration at time t
-
X
0 mg/l
initial biomass concentration
Abbreviations MTCC
Microbial Type Culture Collection
- IMTECH
Institute of Microbial Technology
The cooperation of the staff of the Biosciences and Biotechnology Center, I.I.T. Madras is greatly appreciated. 相似文献
10.
The aim of the study was to demonstrate seasonal changes in the hydrolytic and transferase activity of neutral α-glucosidase, the level of glucose, cholesterol, triglycerides and total protein in the annual breeding cycle of the carp. The study was conducted on fish from a fish farm in Lower Silesia (Poland). Blood serum was collected from the heart in: June, September and December of two consecutive years. The results of the study show that the hydrolytic and transferase activity of neutral α-glucosidase, as well as the results of basic biochemical parameters are highest in summer, when the fish seek and intake food intensively. The lowest values were observed in spring, when carp have the lowest metabolism after the wintering period. 相似文献