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With the isolation and characterization of the key enzymes and proteins, and the corresponding genes, involved in ethylene biosynthesis and sensing it has become possible to manipulate plant ethylene levels and thereby alter a wide range of physiological processes. The phytohormone ethylene is an essential signaling molecule that affects a large number of physiological processes; plants deprived of ethylene do not grow and develop normally. In a search for flexible on-off ethylene control, scientists have used inducible organ- and tissue-specific promoters to drive expression of different transgenes. Here, the various strategies that have been used to genetically engineer plants with decreased ethylene biosynthesis and sensitivity are reviewed and discussed. 相似文献
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The potential of nanodiamond bullets for use in ballistic delivery of biologically active molecules was investigated. Detonation
nanodiamond particles were coated with DNA, synthetic ethylene precursor, or ethylene antagonist or were labeled with fluorescent
dyes and delivered into bacteria, yeast, insect cells, and plant tissues with the help of a Bio-Rad particle delivery system
PDS-1000/He. Detonation nanodiamonds are both mechanically and chemically stable and can be used as DNA carriers for biolistic
transformation of cells and in delivery of biologically active molecules. 相似文献
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Grichko Varvara P.; Gettelman Gwen J.; Widrick Jeffrey J.; Fitts Robert H. 《Journal of applied physiology》1999,86(1):335-340
Results from the Russian Cosmos program suggest that the rhesusmonkey is an excellent model for studying weightlessness-induced changes in muscle function. Consequently, the purpose of this investigation was to establish the resting levels of selected substrateand enzymes in individual slow- and fast-twitch muscle fibers of therhesus monkey. A second objective was to determine the effect of an18-day sit in the Spacelab experiment-support primate facility[Experimental System for the Orbiting Primate (ESOP)].Muscle biopsies of the soleus and medial gastrocnemius muscles wereobtained 1 mo before and immediately after an 18-day ESOP sit. Thebiopsies were freeze-dried, and individual fibers were isolated andassayed for the substrates glycogen and lactate and for the high-energyphosphates ATP and phosphocreatine. Fiber enzyme activity was alsodetermined for the glycolytic enzymes phosphofructokinase and lactatedehydrogenase (LDH) and for the oxidative markers 3-hydroxyacyl-CoAdehydrogenase (-OAC) and citrate synthase. Consistent with otherspecies, the fast type II fibers contained higher glycogen content thandid the slow type I fibers. The ESOP sit had no significant effects onthe metabolic profile of the slow fibers of either muscle or the fast fibers of the soleus. However, the fast gastrocnemius fibers showed asignificant decline in phosphocreatine and an increase in lactate. Also, similar to other species, the fast fibers contained significantly higher LDH activities and lower 3-hydroxyacyl-CoA dehydrogenase activities. For the muscle enzymes, the quantitatively most important effect of the ESOP sit occurred with LDH where activities increased inall fiber types postsit except the slow type I fiber of the medial gastrocnemius. 相似文献
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Saleema?Saleh-Lakha Varvara?P.?Grichko Edward?C.?Sisler Bernard?R.?GlickEmail author 《Journal of Plant Growth Regulation》2004,23(4):307-312
Increased levels of ethylene in plants are responsible for many deleterious effects such as early senescence, fruit deterioration
and inhibition of root elongation. Several cyclopropene derivatives have previously been studied as inhibitors of ethylene
action in plants. This study focuses on one such compound, 1-cyclopropenylmethyl butyl ether and its effect on the growth
of roots and shoots of canola plants as well as rooting of mung bean seedlings 1-cyclopropenylmethyl butyl ether increased
root length in canola plants, but had no significant effect on shoot length. In rooting studies, mung bean seedlings treated
with 1-cyclopropenylmethyl butyl ether prior to root excision had fewer numbers of roots than control plants that were not
treated with the ethylene action inhibitor. The same rooting study, when repeated in the presence of 1-aminocyclopropane-1-carboxylic
acid (ACC), demonstrated an overall increase in the number of roots of inibitor-treated and non-treated plants, however, the
inhibitor was still effective in decreasing the number of roots, compared to its non-treated conterpart.
Online publication: 7 April 2005 相似文献
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Rodriguez BJ Kalinin SV Shin J Jesse S Grichko V Thundat T Baddorf AP Gruverman A 《Journal of structural biology》2006,153(2):151-159
The majority of calcified and connective tissues possess complex hierarchical structure spanning the length scales from nanometers to millimeters. Understanding the biological functionality of these materials requires reliable methods for structural imaging on the nanoscale. Here, we demonstrate an approach for electromechanical imaging of the structure of biological samples on the length scales from tens of microns to nanometers using piezoresponse force microscopy (PFM), which utilizes the intrinsic piezoelectricity of biopolymers such as proteins and polysaccharides as the basis for high-resolution imaging. Nanostructural imaging of a variety of protein-based materials, including tooth, antler, and cartilage, is demonstrated. Visualization of protein fibrils with sub-10nm spatial resolution in a human tooth is achieved. Given the near-ubiquitous presence of piezoelectricity in biological systems, PFM is suggested as a versatile tool for micro- and nanostructural imaging in both connective and calcified tissues. 相似文献
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Limb muscles from rats flown in space and after hindlimb unloading (HU) show an increased fatigability, and spaceflight has been shown to result in a reduced ability to oxidize fatty acids. The purpose of this investigation was to determine the effects of HU on the substrate content in fast- and slow-twitch fibers and to assess the substrate utilization patterns in single slow type I fibers isolated from control and HU animals. A second objective was to assess whether HU altered the ability of the heart or limb muscle to oxidize pyruvate or palmitate. After 2 wk of HU, single fibers were isolated from the freeze-dried soleus and gastrocnemius muscles. HU increased the glycogen content in all fiber types, and it increased lactate, ATP, and phosphocreatine in the slow type I fiber. After HU, the type I fiber substrate profile was shifted toward that observed in fast fibers. For example, fiber glycogen increased from 179 +/- 16 to 285 +/- 25 mmol/kg dry wt, which approached the 308 +/- 23 mmol/kg dry wt content observed in the post-HU type IIa fiber. With contractile activity, the type I fiber from the HU animal showed a greater utilization of glycogen and accumulation of lactate compared with the control type I fiber. HU had no effect on the ability of crude homogenate or mitochondria fractions from the soleus or gastrocnemius to oxidize pyruvate or palmitate. The increased fatigability after HU may have resulted from an elevated glycolysis producing an increased cell lactate and a decreased pH. 相似文献
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V. Grichko 《Russian Journal of Plant Physiology》2006,53(4):523-529
Twenty cyclopropenes were prepared and their anti-ethylene activity was evaluated in the fruit ripening and plant senescence
bioassays. The treatment of banana fruits with developed antagonists led to delay of fruit ripening. Some antagonists were
capable to extend exhibition life of cut mini carnation flowers as well as delay senescence of bean leaves. The potency of
ethylene antagonists declined with increase in molecular weight and reduction in their solubility in water, irrespective of
bioassay used.
Published in Russian in Fiziologiya Rastenii, 2006, Vol. 53, No. 4, pp. 585–591.
The text was submitted by the author in English. 相似文献
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