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1.
David E. Kenny 《Zoo biology》2001,20(4):245-250
After the loss of an African elephant (Loxodonta africana) in February 1989 at the Denver Zoological Gardens (DZG) with very low circulating serum α‐tocopherol, a long‐term study was initiated with three Asian elephants (Elephas maximus) to evaluate the effect of an oral micellized, water‐soluble, natural source d‐α‐tocopherol supplement. Baseline α‐tocopherol levels were evaluated and found to be approximately 3.75‐fold less than those reported for semi‐free‐ranging Asian Nepalese work camp and free‐ranging African elephants. The DZG elephants were then administered a liquid d‐α‐tocopherol (Emcelle®) at 2.2 IU/kg body weight orally once daily. Serum samples were obtained and analyzed at 1, 2, 8, and 12 months and then annually for 96 months. The oral vitamin E supplement significantly elevated serum levels above baseline and were found to be comparable with levels reported for semi–free‐ranging and free‐ranging elephants. Zoo Biol 20:245–250, 2001. © 2001 Wiley‐Liss, Inc.  相似文献   

2.
To date, there are no detailed reports of circulating levels of plasma α‐tocopherol and retinol for large samples of free‐ranging African elephants (Loxodonta africana). This survey study measured natural circulating levels of α‐tocopherol as a measure of vitamin E activity and retinol as an indicator of vitamin A activity, in 70 free‐ranging African elephants captured at Kruger National Park as part of a translocation program. Mean levels of α‐tocopherol and retinol were found to be 0.613 ± 0.271 μg/mL and 0.039± 0.007 μg/mL, respectively, and did not vary significantly across sex or age class. Elephants appear to normally have low circulating levels of both these nutrients compared with domestic herbivore species; values from healthy, free‐ranging elephant populations may provide useful data for assessing nutrient status of captive animals. Zoo Biol 18:319–323, 1999.© 1999 Wiley‐Liss, Inc.  相似文献   

3.
Hippocampus dentate gyrus (DG) is characterized by neuronal plasticity processes in adulthood, and polysialylation of NCAM promotes neuronal plasticity. In previous investigations we found that α‐tocopherol increased the PSA‐NCAM‐positive granule cell number in adult rat DG, suggesting that α‐tocopherol may enhance neuronal plasticity. To verify this hypothesis, in the present study, structural remodeling in adult rat DG was investigated under α‐tocopherol supplementation conditions. PSA‐NCAM expression was evaluated by Western blotting, evaluation of PSA‐NCAM‐positive granule cell density, and morphometric analysis of PSA‐NCAM‐positive processes. In addition, the optical density of synaptophysin immunoreactivity and the synaptic profile density, examined by electron microscopy, were evaluated. Moreover, considering that PSA‐NCAM expression has been found to be related to PKCδ activity and α‐tocopherol has been shown to inhibit PKC activity in vitro, Western blotting and immunohistochemistry followed by densitometry were used to analyze PKC. Our results demonstrated that an increase in PSA‐NCAM expression and optical density of DG molecular layer synaptophysin immunoreactivity occurred in α‐tocopherol‐treated rats. Electron microscopy analysis showed that the increase in synaptophysin expression was related to an increase in synaptic profile density. In addition, Western blotting revealed a decrease in phospho‐PKC Pan and phospho‐PKCδ, demonstrating that α‐tocopherol is also able to inhibit PKC activity in vivo. Likewise, immunoreactivity for the active form of PKCδ was lower in α‐tocopherol‐treated rats than in controls, while no changes were found in PKCδ expression. These results demonstrate that α‐tocopherol is an exogenous factor affecting neuronal plasticity in adult rat DG, possibly through PKCδ inhibition. © 2006 Wiley Periodicals, Inc. J Neurobiol, 2006  相似文献   

4.
Flow injection (FI) methods are reported to determine retinol and α‐tocopherol based on its enhancement affect of lucigenin chemiluminescence (CL) in alkaline medium. Surfactants including Brij‐35, Triton X‐100, cetyltrimethyl ammonium bromide (CTAB) and sodium dodecyl sulfate have been reported for the first time to enhance lucigenin CL intensity in the presence of retinol and α‐tocopherol. With Brij‐35, the CL intensity was enhanced by 67% for retinol and 58% for α‐tocopherol. CTAB was found to enhance the CL intensity by 16% for retinol whereas for α‐tocopherol, the CL intensity was quenched up to 95%. Retinol could be determined specifically in the presence of α‐tocopherol using CTAB. The calibration graphs were found to be linear up to 1.43 mg/L (R2 = 0.9985, n = 8) with a detection limit (3s) of 1.43 × 10?3 mg/L for retinol and 2.15 mg/L (R2 = 0.9989; n = 8) with a detection limit (3s) of 4.31 × 10?4 mg/L for α‐tocopherol. An injection throughput of 120/h, and relative standard deviations of 0.9–2.8% (n = 4) were achieved in the concentration range studied. The influence of common ions, excipients in pharmaceutical formulations and related organic compounds on the determination of retinol and α‐tocopherol individually was studied. The proposed methods were applied to determine retinol and α‐tocopherol in pharmaceutical formulations and human blood serum. The results did not differ significantly from the CL method and HPLC reference method at 95% confidence level. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   

5.
A simple one‐dimensional 13C NMR method is presented to discriminate between stereoisomers of organic compounds with more than one chiral center. By means of this method it is possible to discriminate between all eight stereoisomers of α‐tocopherol. To achieve this the chiral solvating agent (S)‐(+)‐1‐(9‐anthryl)‐2,2,2‐trifluoroethanol and the compound of interest were dissolved in high concentrations in chloroform‐d, and the nuclear magnetic resonance (NMR) spectrum was recorded at a low temperature. The individual stereoisomers of α‐tocopherol were assigned by spikes of the reference compounds. The method was also applied to six other representative examples. Chirality 27:850–855, 2015. © 2015 Wiley Periodicals, Inc.  相似文献   

6.
Whey proteins have high nutritional value providing use in dietary purposes and improvement of technological properties in processed foods. Functionality of the whey‐based α‐lactalbumin (α‐La) may be increased when assembled in the form of nanotubes, promising novel potential applications subject to investigation. The purpose of this study was to extract highly pure α‐La from whey protein isolate (WPI) and whey powder (WP) and to construct protein nanotubes from them for industrial applications. For protein fractionation, WPI was directly fed to chromatography, however, WP was first subjected to membrane filtration and the retentate fraction, whey protein concentrate (WPC), was obtained and then used for chromatographic separation. α‐La and, additionally β‐Lg, were purified at the same batches with the purities in the range of 95%–99%. After enzymatic hydrolysis, WPI‐based α‐La produced chain‐like and long nanotubules with ~20 nm width while WPC‐based α‐La produced thinner, miscellaneous, and fibril‐like nanostructures by self‐assembly. Raman and FT‐IR spectroscopies revealed that α‐La fractions, obtained from both sources and the nanostructures, developed using both fractions have some structural differences due to conformation of secondary structure elements. Nanotube formation induced gelation and nanotubular gel network entrapped a colorant uniformly with a transparent appearance. Dairy‐based α‐La protein nanotubules could be served as alternative gelling agents and the carriers of natural colorants in various food processes. © 2014 American Institute of Chemical Engineers Biotechnol. Prog., 30:1301–1310, 2014  相似文献   

7.
Aims: To analyse the production of different metabolites by dark‐grown Euglena gracilis under conditions found to render high cell growth. Methods and Results: The combination of glutamate (5 g l?1), malate (2 g l?1) and ethanol (10 ml l?1) (GM + EtOH); glutamate (7·15 g l?1) and ethanol (10 ml l?1); or malate (8·16 g l?1), glucose (10·6 g l?1) and NH4Cl (1·8 g l?1) as carbon and nitrogen sources, promoted an increase of 5·6, 3·7 and 2·6‐fold, respectively, in biomass concentration in comparison with glutamate and malate (GM). In turn, the production of α‐tocopherol after 120 h identified by LC‐MS was 3·7 ± 0·2, 2·4 ± 0·1 and 2 ± 0·1 mg [g dry weight (DW)]?1, respectively, while in the control medium (GM) it was 0·72 ± 0·1 mg (g DW)?1. For paramylon synthesis, the addition of EtOH or glucose induced a higher production. Amino acids were assayed by RP‐HPLC; Tyr a tocopherol precursor and Ala an amino acid with antioxidant activity were the amino acids synthesized at higher concentration. Conclusions: Dark‐grown E. gracilis Z is a suitable source for the generation of the biotechnologically relevant metabolites tyrosine, α‐tocopherol and paramylon. Significance and Impact of the Study: By combining different carbon and nitrogen sources and inducing a tolerable stress to the cell by adding ethanol, it was possible to increase the production of biomass, paramylon, α‐tocopherol and some amino acids. The concentrations of α‐tocopherol achieved in this study are higher than others reported previously for Euglena, plant and algal systems. This work helps to understand the effect of different carbon sources on the synthesis of bio‐molecules by E. gracilis and can be used as a basis for future works to improve the production of different metabolites of biotechnological importance by this organism.  相似文献   

8.
3‐Hydroxy‐3‐methylglutaryl‐coenzyme A synthase (HMGS) in the mevalonate (MVA) pathway generates isoprenoids including phytosterols. Dietary phytosterols are important because they can lower blood cholesterol levels. Previously, the overexpression of Brassica juncea wild‐type (wt) and mutant (S359A) BjHMGS1 in Arabidopsis up‐regulated several genes in sterol biosynthesis and increased sterol content. Recombinant S359A had earlier displayed a 10‐fold higher in vitro enzyme activity. Furthermore, tobacco HMGS overexpressors (OEs) exhibited improved sterol content, plant growth and seed yield. Increased growth and seed yield in tobacco OE‐S359A over OE‐wtBjHMGS1 coincided with elevations in NtSQS expression and sterol content. Herein, the overexpression of wt and mutant (S359A) BjHMGS1 in a crop plant, tomato (Solanum lycopersicum), caused an accumulation of MVA‐derived squalene and phytosterols, as well as methylerythritol phosphate (MEP)‐derived α‐tocopherol (vitamin E) and carotenoids, which are important to human health as antioxidants. In tomato HMGS‐OE seedlings, genes associated with the biosyntheses of C10, C15 and C20 universal precursors of isoprenoids, phytosterols, brassinosteroids, dolichols, methylerythritol phosphate, carotenoid and vitamin E were up‐regulated. In OE‐S359A tomato fruits, increased squalene and phytosterol contents over OE‐wtBjHMGS1 were attributed to heightened SlHMGR2, SlFPS1, SlSQS and SlCYP710A11 expression. In both tomato OE‐wtBjHMGS1 and OE‐S359A fruits, the up‐regulation of SlGPS and SlGGPPS1 in the MEP pathway that led to α‐tocopherol and carotenoid accumulation indicated cross‐talk between the MVA and MEP pathways. Taken together, the manipulation of BjHMGS1 represents a promising strategy to simultaneously elevate health‐promoting squalene, phytosterols, α‐tocopherol and carotenoids in tomato, an edible fruit.  相似文献   

9.
Aims: To characterize of a thermostable recombinant α‐l ‐arabinofuranosidase from Caldicellulosiruptor saccharolyticus for the hydrolysis of arabino‐oligosaccharides to l ‐arabinose. Methods and Results: A recombinant α‐l ‐arabinofuranosidase from C. saccharolyticus was purified by heat treatment and Hi‐Trap anion exchange chromatography with a specific activity of 28·2 U mg?1. The native enzyme was a 58‐kDa octamer with a molecular mass of 460 kDa, as measured by gel filtration. The catalytic residues and consensus sequences of the glycoside hydrolase 51 family of α‐l ‐arabinofuranosidases were completely conserved in α‐l ‐arabinofuranosidase from C. saccharolyticus. The maximum enzyme activity was observed at pH 5·5 and 80°C with a half‐life of 49 h at 75°C. Among aryl‐glycoside substrates, the enzyme displayed activity only for p‐nitrophenyl‐α‐l ‐arabinofuranoside [maximum kcat/Km of 220 m(mol l?1)?1 s?1] and p‐nitrophenyl‐α‐l ‐arabinopyranoside. This substrate specificity differs from those of other α‐l ‐arabinofuranosidases. In a 1 mmol l?1 solution of each sugar, arabino‐oligosaccharides with 2–5 monomer units were completely hydrolysed to l ‐arabinose within 13 h in the presence of 30 U ml?1 of enzyme at 75°C. Conclusions: The novel substrate specificity and hydrolytic properties for arabino‐oligosaccharides of α‐l ‐arabinofuranosidase from C. saccharolyticus demonstrate the potential in the commercial production of l ‐arabinose in concert with endoarabinanase and/or xylanase. Significance and Impact of the Study: The findings of this work contribute to the knowledge of hydrolytic properties for arabino‐oligosaccharides performed by thermostable α‐l ‐arabinofuranosidase.  相似文献   

10.
Vinpocetine is a neuroprotective drug that exerts beneficial effects on neurological symptoms and cerebrovascular disease. 3‐nitropropionic acid (3‐NPA) is a toxin that irreversibly inhibits succinate dehydrogenase, the mitochondrial enzyme that acts in the electron transport chain at complex II. In previous studies in striatum‐isolated nerve endings (synaptosomes), we found that vinpocetine decreased dopamine (DA) at expense of its main metabolite 3,4‐dihydroxyphenylacetic acid (DOPAC), and that 3‐NPA increased DA, reactive oxygen species (ROS), DA‐quinone products formation, and decreased DOPAC. Therefore, in this study, the possible effect of vinpocetine on 3‐NPA‐induced increase in DA, ROS, lipid peroxidation, and DA‐quinone products formation in striatum synaptosomes were investigated, and compared with the effects of the antioxidant α‐tocopherol. Results show that the increase in DA induced by 3‐NPA was inhibited by both 25 μM vinpocetine and 50 μM α‐tocopherol. Vinpocetine, as α‐tocopherol, also inhibited 3‐NPA‐induced increase in ROS (as judged by DCF fluorescence), lipid peroxidation (as judged by TBA‐RS formation), and DA‐quinone products formation (as judged by the nitroblue tetrazolium reduction method). As in addition to the inhibition of complex II exerted by 3‐NPA, 3‐NPA increases DA‐oxidation products that in turn can inhibit other sites of the respiratory chain, the drop in DA produced by vinpocetine and α‐tocopherol may importantly contribute to their protective action from oxidative damage, particularly in DA‐rich structures.  相似文献   

11.
3‐Fucosyllactose (3‐FL), one of the major oligosaccharides in human breast milk, is produced in engineered Escherichia coli. In order to search for a good α‐1,3‐fucosyltransferase, three bacterial α‐1,3‐fucosyltransferases are expressed in engineered E. coli deficient in β‐galactosidase activity and expressing the essential enzymes for the production of guanosine 5′‐diphosphate‐l ‐fucose, the donor of fucose for 3‐FL biosynthesis. Among the three enzymes tested, the fucT gene from Helicobacter pylori National Collection of Type Cultures 11637 gives the best 3‐FL production in a simple batch fermentation process using glycerol as a carbon source and lactose as an acceptor. In order to use glucose as a carbon source, the chromosomal ptsG gene, considered the main regulator of the glucose repression mechanism, is disrupted. The resulting E. coli strain of ?LP‐YA+FT shows a much lower performance of 3‐FL production (4.50 g L?1) than the ?L‐YA+FT strain grown in a glycerol medium (10.7 g L?1), suggesting that glycerol is a better carbon source than glucose. Finally, the engineered E. coli ?LW‐YA+FT expressing the essential genes for 3‐FL production and blocking the colanic acid biosynthetic pathway (?wcaJ) exhibits the highest concentration (11.5 g L?1), yield (0.39 mol mol?1), and productivity (0.22 g L?1 h) of 3‐FL in glycerol‐limited fed‐batch fermentation.  相似文献   

12.
The present work was aimed to evaluate the protective effects of alpha‐tocopherol (α‐toco) and/or Lactobacillus plantarum (LCB) against testicular atrophy induced by mercuric chloride (MCH). Rats were injected with 5 mg/kg MCH for 5 days consecutively, then treated with 100 mg/kg α‐toco and 6 × 1010 CFU 1.8701/kg LCB alone or together for 3 weeks. The MCH elevated serum TNF‐α, IL‐ 6, caspase‐3, and testicular malondialdehyde. However, serum testosterone, dehydroepiandrosterone, testicular messenger RNA of a steroidogenic acute regulatory protein, 17‐β‐hydroxysteroid dehydrogenase, 3β‐hydroxysteroid dehydrogenase, glutathione level, and superoxide dismutase activity were decreased. Protein expression of Nrf2 was downregulated whereas that of Bax and DNA fragmentation was upregulated in the testicular tissues. Treatment with α‐toco and LCB ameliorated the deviated biochemical parameters and improved tissue injury. It was concluded that the combination of LCB and α‐toco achieved promising results in the amelioration of MCH‐induced testicular atrophy. Nrf2, Bax expressions, and DNA fragmentation are involved in the testicular atrophy induced by MCH.  相似文献   

13.
One skin cancer prevention strategy that we are developing is based on synthesizing and testing melanocortin analogs that reduce and repair DNA damage resulting from exposure to solar ultraviolet (UV) radiation, in addition to stimulating pigmentation. Previously, we reported the effects of tetrapeptide analogs of α‐melanocortin (α‐MSH) that were more potent and stable than the physiological α‐MSH, and mimicked its photoprotective effects against UV‐induced DNA damage in human melanocytes. Here, we report on a panel of tripeptide analogs consisting of a modified α‐MSH core His6‐d ‐Phe7‐Arg8, which contained different N‐capping groups, C‐terminal modifications, or arginine mimics. The most potent tripeptides in activating cAMP formation and tyrosinase of human melanocytes were three analogs with C‐terminal modifications. The most effective C‐terminal tripeptide mimicked α‐MSH in reducing hydrogen peroxide generation and enhancing nucleotide excision repair following UV irradiation. The effects of these three analogs required functional MC1R, as they were absent in human melanocytes that expressed non‐functional receptor. These results demonstrate activation of the MC1R by tripeptide melanocortin analogs. Designing small analogs for topical delivery should prove practical and efficacious for skin cancer prevention.  相似文献   

14.
The γ‐tocopherol methyltransferase (γ‐TMT) is an important enzyme regulating synthesis of four tocopherols (α, γ, β and δ). In this report, we investigated the role of γ‐TMT in regulating abiotic stress within chloroplasts. The At γ‐tmt overexpressed via the tobacco chloroplast genome accumulated up to 7.7% of the total leaf protein, resulting in massive proliferation of the inner envelope membrane (IEM, up to eight layers). Such high‐level expression of γ‐TMT converted most of γ‐tocopherol to α‐tocopherol in transplastomic seeds (~10‐fold higher) in the absence of abiotic stress. When grown in 400 mm NaCl, α‐tocopherol content in transplastomic TMT leaves increased up to 8.2‐fold and 2.4‐fold higher than wild‐type leaves. Likewise, under heavy metal stress, α‐tocopherol content in the TMT leaves increased up to 7.5‐fold, twice higher than in the wild type. Under extreme salt stress, the wild type accumulated higher starch and total soluble sugars, but TMT plants were able to regulate sugar transport. Hydrogen peroxide and superoxide content in wild type increased up to 3‐fold within 48 h of NaCl stress when compared to TMT plants. The ion leakage from TMT leaves was significantly less than wild‐type plants under abiotic stress and with less malondialdehyde, indicating lower lipid peroxidation. Taken together, these studies show that α‐tocopherol plays a crucial role in the alleviation of salt and heavy metal stresses by decreasing ROS, lipid peroxidation and ion leakage, in addition to enhancing vitamin E conversion. Increased proliferation of the IEM should facilitate studies on retrograde signalling from chloroplast to the nucleus.  相似文献   

15.
α‐Glycosidase is a catalytic enzyme and it destroys the complex carbohydrates into simple absorbable sugar units. The natural phenolic compounds were tested for their antidiabetic properties as α‐glycosidase and α‐amylase inhibitors. The phenolic compounds investigated in this study have been used as antidiabetic common medicines. This paper aimed to consider their capability to inhibit α‐amylase and α‐glycosidase, two significant enzymes defined in serum glucose adjustment. These examination recorded impressive inhibition profiles with IC50 values in the range of 137.36–737.23 nM against α‐amylase and 29.01–157.96 nM against α‐glycosidase.  相似文献   

16.
Herbivorous insects exploit multiple plant cues to detect and orient toward suitable hosts and, accordingly, hosts have evolved complex constitutive and inducible defenses in response. In China, the red turpentine beetle, Dendroctonus valens LeConte (Coleoptera: Curculionidae: Scolytinae), an invasive bark beetle from North America, attacks mainly Pinus tabuliformis Carrière (Pinaceae), which contains many monoterpenes. In this study, we explored how the monoterpene α‐pinene affects the feeding performance and pheromone production of D. valens. First, the composition and quantities of monoterpenes of both P. tabuliformis healthy trees and fresh stumps were determined and the infestation of D. valens in healthy trees and fresh stumps was investigated, linking the amount of monoterpenes and D. valens infestation. Gas chromatography–mass spectrometry (GC‐MS) analysis showed that P. tabuliformis mainly contained α‐pinene, with concentrations of 0.1 and 0.5 mg g?1 in healthy pine phloem and stump phloem, respectively. Second, the monoterpene's influence on feeding performance was tested using phloem media with α‐pinene concentrations ranging from 0 to 30 mg g?1. The results showed that the percentages of beetles boring and the gallery lengths of both adult females and larvae were negatively correlated with the α‐pinene concentration although body weight changes did not correlate with α‐pinene concentration. Finally, pheromone analysis showed that the production of all pheromones increased with increasing α‐pinene concentrations. This study showed the dual effects of α‐pinene on D. valens: α‐pinene inhibited the bark beetle's feeding activities and in turn the bark beetle made use of it to produce pheromones. Our study indicated the importance of promptly removing fresh stumps in the field for the management of the bark beetle.  相似文献   

17.
True bugs (Hemiptera) are an important pest complex not controlled by Bt‐transgenic crops. An alternative source of resistance includes inhibitors of digestive enzymes, such as protease or amylase inhibitors. αAI‐1, an α‐amylase inhibitor from the common bean, inhibits gut‐associated α‐amylases of bruchid pests of grain legumes. Here we quantify the in vitro activity of α‐amylases of 12 hemipteran species from different taxonomic and functional groups and the in vitro inhibition of those α‐amylases by αAI‐1. α‐Amylase activity was detected in all species tested. However, susceptibility to αAI‐1 varied among the different groups. α‐Amylases of species in the Lygaeidae, Miridae and Nabidae were highly susceptible, whereas those in the Auchenorrhyncha (Cicadellidae, Membracidae) had a moderate susceptibility, and those in the Pentatomidae seemed to be tolerant to αAI‐1. The species with αAI‐1 susceptible α‐amylases represented families which include both important pest species but also predatory species. These findings suggest that αAI‐1‐expressing crops have potential to control true bugs in vivo.  相似文献   

18.
Stem cell transplantation is a candidate method for the treatment of Leydig cell dysfunction‐related diseases. However, there are still many problems that limit its clinical application. Here, we report the establishment of CXCR4‐SF1 bifunctional adipose‐derived stem cells (CXCR4‐SF1‐ADSCs) and their reparative effect on Leydig cell dysfunction. CD29+ CD44+ CD34? CD45? ADSCs were isolated from adipose tissue and purified by fluorescence‐activated cell sorting (FACS). Infection with lentiviruses carrying the CXCR4 and SF1 genes was applied to construct CXCR4‐SF1‐ADSCs. The CXCR4‐SF1‐ADSCs exhibited enhanced migration and had the ability to differentiate into Leydig‐like cells in vitro. Furthermore, the bifunctional ADSCs were injected into BPA‐mediated Leydig cell damage model mice via the tail vein. We found that the CXCR4‐SF1‐ADSCs were capable of homing to the injured testes, differentiating into Leydig‐like cells and repairing the deficiency in reproductive function caused by Leydig cell dysfunction. Moreover, we investigated the mechanism underlying SF1‐mediated differentiation and testosterone synthesis in Leydig cells, and the B‐box and SPRY Domain Containing Protein (BSPRY) gene was proposed to be involved in this process. This study provides insight into the treatment of Leydig cell dysfunction‐related diseases.  相似文献   

19.
4‐α‐Glucanotransferase (GTase, D ‐enzyme) catalyzes disproportionation between two short polymers of maltooligosaccharides linked by α‐1,4‐glucoside bonds. Using action modes of the potato GTase for the donor and acceptor substrates, the Monte Carlo method was applied to simulate the GTase reaction. The simulation starts from a single enzyme molecule and a finite number (105) of substrate molecules. All selection processes were performed using random numbers produced by computer. The initial substrates were from trimer to 10‐mer. In every case, the final stage was the steady‐state distribution of polymers. The steady‐state distribution by the potato GTase reaction was different from those by the hypothetical random disproportionation reaction. The simulated data from the reaction of potato GTase and trimer almost quantitatively agreed with experimental data. The mechanism of the GTase reaction was accumulation of probabilistic processes and was well simulated by the Monte Carlo method. GTase randomizes the overall distribution of chain length of the substrate. Therefore the GTase reaction is an entropy‐driven process. © 1999 John Wiley & Sons, Inc. Biopoly 50: 145–151, 1999  相似文献   

20.
To develop an optimal attractant for Monochamus saltuarius (Gebler) (Coleoptera: Cerambycidae), the synergistic effects of a few potential attractants (ethanol and α‐pinene as host‐plant volatiles, and ipsenol and ipsdienol as bark beetle pheromones) were tested in a pine forest combined with 2‐(1‐undecyloxy)‐1‐ethanol (monochamol), the aggregation pheromone of Monochamus species, for two consecutive years, 2014 and 2015. Total number of catches was 65 and 33 in 2014 and 2015, respectively. Ethanol or ethanol + monochamol (a base blend) were not attractive to M. saltuarius with no difference from the control. Addition of α‐pinene and ipsdienol to the base blend did not significantly increase catches. However, ipsenol was significantly synergistic to the base blend in attracting M. saltuarius in 2014, and the blend (ipsenol + base blend) attracted meaningfully higher numbers of M. saltuarius in 2015. Our study illustrates the potential for monochamol and ipsenol baits for monitoring and trapping of M. saltuarius in the field.  相似文献   

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