赤霉素和钙处理春小麦种子效应的研究   总被引：9，自引：2，他引：9  

徐萌  山仑 《种子》1990,(4):25-28

分段研究了GA和Ca~(2+)对种子成苗过程的吸涨、萌发和胚芽伸长3个阶段的影响。在吸涨阶段和萌发阶段,GA具有明显促进种子吸水和加快种子萌发的作用。Ca~(2+)则表现出抑制种子吸水和萌发。GA能够促进胚芽和芽鞘的伸长。Ca~(2+)则明显抑制了胚芽和芽鞘的伸长。GA促进成苗的主要因为它增大了种苗的导水性,从而加快了种苗吸收水分,由此促进了种子萌动、萌发和胚芽伸长。GA与Ca~(2+)混合后,Ca~(2+)抑制了GA对种子吸水、萌发和胚芽生长的促进作用,由此推断,干旱条件下Ca~(2+)对种子成苗的有利作用机理不同于GA。在干旱和半干旱地区,种子萌发和出土过程常常受到干旱的威胁,因此,加快种子萌发和出土对作物产量形成有着十分重要的意义。用植物激素、营养元素和其它化学药剂处理种子已有大量报道。有试验证明,一定浓度的GA有促进多种作物种子萌发和幼苗生长的作用。Ca~(2+)对种子萌发和幼苗生长的作用也有不少研究。我们的试验也证明,中度干旱条件下,GA和Ca~(2+)分别处理种子,确有促进根芽伸长、加快出苗速度和提高出苗率的作用(2)(3),并且提出用GA和Ca~(2+)混合处理种子,有互补作用。上述研究只是证明了GA和Ca~(2+)处理种子的作用效果对GA和Ca~(2+)的作用机理深入探讨不够,并且缺乏对GA和Ca~(2+)在种子吸涨—出土这一连续成苗过程的分段作用效果的研究。因此,本试验基于原有工作,对GA和Ca~(2+)在整个成苗过程各个阶段的作用效果和机制进行了初步探讨。  相似文献   

Cancer-preventive peptide lunasin from Solanum nigrum L. inhibits acetylation of core histones H3 and H4 and phosphorylation of retinoblastoma protein (Rb)   总被引：1，自引：0，他引：1  

Jeong JB  Jeong HJ  Park JH  Lee SH  Lee JR  Lee HK  Chung GY  Choi JD  de Lumen BO 《Journal of agricultural and food chemistry》2007,55(26):10707-10713

Lunasin, a unique 43 amino acid, 4.8 kDa cancer-chemopreventive peptide initially reported in soybean and now found in barley and wheat, has been shown to be cancer-chemopreventive in mammalian cells and in a skin cancer mouse model against oncogenes and chemical carcinogens. To identify bioactive components in traditional herbal medicines and in search for new sources of lunasin, we report here the properties of lunasin from Solanum nigrum L. (SNL), a plant indigenous to northeast Asia. Lunasin was screened in the crude extracts of five varieties of the medicinal plants of Solanaceae origin and seven other major herbal plants. An in vitro digestion stability assay for measuring bioavailability was carried out on SNL crude protein and autoclaved SNL using pepsin and pancreatin. A nonradioactive histone acetyltransferase (HAT) assay and HAT activity colorimetric assay were used to measure the inhibition of core histone acetylation. The inhibitory effect of lunasin on the phosphorylation of retinoblastoma protein (Rb) was determined by immunoblotting against phospho-Rb. Lunasin isolated from autoclaved SNL inhibited core histone H3 and H4 acetylation, the activities of the HATs, and the phosphorylation of the Rb protein. Lunasin in the crude protein and in the autoclaved crude protein was very stable to pepsin and pancreatin in vitro digestion, while the synthetic pure lunasin was digested at 2 min after the reaction. We conclude that lunasin is a bioactive and bioavailable component in SNL and that consumption of SNL may play an important role in cancer prevention.  相似文献   

Monitoring the binding processes of black tea thearubigin to the bovine serum albumin surface using quartz crystal microbalance with dissipation monitoring   总被引：2，自引：0，他引：2  

Chitpan M  Wang X  Ho CT  Huang Q 《Journal of agricultural and food chemistry》2007,55(25):10110-10116

The binding processes of thearubigin, which is one of the two major polyphenols (the other one is theaflavin) that gives black tea its characteristic color and taste, to the bovine serum albumin (BSA) surface have been investigated by quartz crystal microbalance with dissipation monitoring (QCM-D). The mass and thickness of the thearubigin adlayer on BSA surfaces at various thearubigin concentrations, salt concentrations, and pH values have been determined by QCM-D using the Voigt model. Our results show that the adsorption isotherm of thearubigin on the BSA surface can be better described by the Langmuir model than the Freundlich model, suggesting that the thearubigin adsorption on the BSA surface is dominated by specific interactions, such as electrostatic interaction and hydrogen bonding, as evidenced by the stronger thearubigin adsorption at pH below the isoelectric point (pI) of BSA and shifts in the positions of both amide bands in the FTIR spectra of the BSA surface with and without thearubigin adsorption. The addition of salt can also influence the thearubigin binding to BSA surfaces. The salt concentration-enhanced effect at a salt concentration lower than 0.1 M is explained as that an increase of salt concentration can screen the electrostatic repulsion to a larger extent than the electrostatic attraction between thearubigin and BSA. On the other hand, when the salt concentration is higher than 0.1 M, both electrostatic repulsion and attraction can be significantly screened by the higher salt concentration, resulting in the salt concentration-reduced effect. However, when the salt concentration is further increased to 0.4 M, the addition of thearubigin may promote the formation of a certain type of complex with BSA, resulting in the increases of both thickness and mass of the thearubigin adlayer.  相似文献   

Ginger and its bioactive component inhibit enterotoxigenic Escherichia coli heat-labile enterotoxin-induced diarrhea in mice     

Chen JC  Huang LJ  Wu SL  Kuo SC  Ho TY  Hsiang CY 《Journal of agricultural and food chemistry》2007,55(21):8390-8397

Ginger is one of the most commonly used fresh herbs and spices. Enterotoxigenic Escherichia coli heat-labile enterotoxin (LT)-induced diarrhea is the leading cause of infant death in developing countries. In this study, we demonstrated that ginger significantly blocked the binding of LT to cell-surface receptor G M1, resulting in the inhibition of fluid accumulation in the closed ileal loops of mice. Biological-activity-guided searching for active components showed that zingerone (vanillylacetone) was the likely active constituent responsible for the antidiarrheal efficacy of ginger. Further analysis of chemically synthesized zingerone derivatives revealed that compound 31 (2-[(4-methoxybenzyl)oxy]benzoic acid) significantly suppressed LT-induced diarrhea in mice via an excellent surface complementarity with the B subunits of LT. In conclusion, our findings provide evidence that ginger and its derivatives may be effective herbal supplements for the clinical treatment of enterotoxigenic Escherichia coli diarrhea.  相似文献   

Self-diffusion coefficient of water in tofu determined by pulsed field gradient nuclear magnetic resonance     

Hong YS  Lee CH 《Journal of agricultural and food chemistry》2006,54(1):219-223

The self-diffusion coefficient of water in soybean protein dispersion and tofu was measured by pulsed field gradient (PFG) NMR. A soy protein isolate (SPI) dispersion (6 and 12%, w/w) in water, calcium cross-linked precipitate, and tofu were used for comparison. The self-diffusion coefficient of water (D) in the SPI dispersion, 2.23 x 10(-9) m2/s, was estimated lower than that of free water, 2.6 x 10(-9) m2/s at 25 degrees C, and decreased as the SPI concentration increased. It further decreased by the addition of calcium chloride, reflecting the obstruction effect induced by the precipitates in addition to the hydration and hydrodynamic interaction in the protein dispersion. The two water regions in tofu were interpreted by the two-site K?rger model: D1 and D2 of soft tofu were 2.26 (+/-0.11) x 10(-9) and 6.84 (+/-0.34) x 10(-11) m2/s, respectively. The relative amount of proton (water) was p1 = 0.98 and p2 = 0.02 at 100 ms of diffusion time. The self-diffusion coefficients of water decreased in pressed tofu, and their relative amounts of water changed to p1 = 0.93 and p2 = 0.07. It was suggested that D1 corresponded to obstructed water in the network structure and D2 corresponded to hydrated water on the surface layer of pores formed in the protein network of tofu. The pore sizes estimated from the diffusion length of obstructed water were 21.3 microm in soft tofu and 20.8 microm in pressed tofu. The removal of fat from pressed tofu led to a decrease in D2 from 6.26 (+/-0.31) x 10(-11) to 3.53 (+/-0.18) x 10(-11) m2/s, and the relative amount of hydrated water increased from 0.07 to 0.14, which indicated hydrophobic hydration.  相似文献   

Survey of gastrointestinal parasitic infections in quarantined dogs in Taiwan     

Ho SY  Watanabe Y  Lee YC  Shih TH  Tu WJ  Ooi HK 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2006,68(1):69-70

Intestinal helminth and protozoan infection in the quarantined dogs in Taiwan were examined using fecal examination between January to December, 2004. Of the 376 dogs imported from 11 countries, 63 (16.8%) were found to be infected with at least one species of intestinal parasite. The parasites detected were oocysts of Isospora canis and eggs of Toxocara canis, Trichuris vulpis and hookworms. Of the 63 infected dogs, 11 were found to have a mixed infection of two different species of parasites. This paper illustrates that parasites are transmitted from one country to another through the transport of animals. Moreover, there is also a possibility of parasitic infection among quarantined dogs as well as the zoonotic potential for quarantine officers during the quarantine period.  相似文献   

Age-related changes in calretinin-immunoreactive periglomerular cells in the rat main olfactory bulb     

Hwang IK  Yoo KY  Nam YS  Choi JH  Seo K  Lee IS  Jung JY  Kang TC  Oh YS  Won MH 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2006,68(5):465-469

The changes of calretinin (CR)-immunoreactive periglomerular cells in the glomerular layer of the main olfactory bulb (MOB) were investigated in rats differing ages from postnatal month 1 (PM 1) to PM 24. The number of cresyl violet-positive periglomerular cells was similar between PM 1 and PM 12, but they decreased slightly in the PM 24 group. The size of CR-immunoreactive periglomerular cells in the glomerular layer increased with age, while their numbers did not change significantly in the PM 6-PM 24 groups. In the PM 24 group, numbers of CR-positive periglomerular cell bodies and their processes decreased, while the size of CR-positive cell bodies in the glomeruli was larger than that of the previous groups. These results suggest that CR-immunoreactive periglomerular cells in the rat MOB are well-developed in the PM 6 group, and that periglomerular cells in the PM 24 group show poor CR-immunoreactivity compared to those in the PM 6 group.  相似文献   

Progressive disruption of cellular protein folding in models of polyglutamine diseases     

Gidalevitz T  Ben-Zvi A  Ho KH  Brignull HR  Morimoto RI 《Science (New York, N.Y.)》2006,311(5766):1471-1474

Numerous human diseases are associated with the chronic expression of misfolded and aggregation-prone proteins. The expansion of polyglutamine residues in unrelated proteins is associated with the early onset of neurodegenerative disease. To understand how the presence of misfolded proteins leads to cellular dysfunction, we employed Caenorhabditis elegans polyglutamine aggregation models. Here, we find that polyglutamine expansions disrupted the global balance of protein folding quality control, resulting in the loss of function of diverse metastable proteins with destabilizing temperature-sensitive mutations. In turn, these proteins, although innocuous under normal physiological conditions, enhanced the aggregation of polyglutamine proteins. Thus, weak folding mutations throughout the genome can function as modifiers of polyglutamine phenotypes and toxicity.  相似文献   

Effect of pH on binding of mutagenic heterocyclic amines by the natural biopolymer poly(gamma-glutamic acid)     

Inbaraj BS  Chiu CP  Chiu YT  Ho GH  Yang J  Chen BH 《Journal of agricultural and food chemistry》2006,54(17):6452-6459

Poly(gamma-glutamic acid) (gamma-PGA), a nontoxic and biodegradable macropolymer, was evaluated for its efficiency in binding three mutagenic heterocyclic amines (HAs), 2-amino-3,4-dimethylimidazo[4,5-f]quinoline (MeIQ), 2-amino-3,4,8-trimethylimidazo[4,5-f]quinoxaline (4,8-DiMeIQx), and 3-amino-1-methyl-5H-pyrido[4,3-b]indole (Trp-p-2), as affected by pH in a batch mode. The maximum HA sorption was attained for pH 3-7 and decreased sharply for pH less than 3. Binding isotherms obtained at pH 2.5 and 5.5 showed different isotherm shapes that belong to S and L types, respectively. The isotherm data at pH 2.5 were well described by a linear form of the Langmuir equation, while at pH 5.5 it showed two distinct curves, which were precisely fitted as multiple Langmuir curves. The deviation of linearity in Scatchard plot proved the multisite HA sorption. The Brunauer-Emmett-Teller equation also fitted better to isotherm data at pH 5.5, suggesting a multisite sorption caused by multimolecular HA layers on gamma-PGA. High HA sorption levels of 1250, 667, and 1429 mg/g at pH 2.5 and 1429, 909, and 1667 mg/g at pH 5.5 were observed for MeIQ, 4,8-DiMeIQx, and Trp-p-2, respectively. Among the HAs studied, the sorption capacity correlated directly with hydrophobicity of HAs and inversely with the number of methyl groups in HA molecules. The plausible binding mechanism of HAs on gamma-PGA may include a combination of hydrophobic, hydrogen-bonding, ionic, and dipole-dipole interactions.  相似文献   

Effects of extraction solvent mixtures on antioxidant activity evaluation and their extraction capacity and selectivity for free phenolic compounds in barley (Hordeum vulgare L.)     

Zhao H  Dong J  Lu J  Chen J  Li Y  Shan L  Lin Y  Fan W  Gu G 《Journal of agricultural and food chemistry》2006,54(19):7277-7286

Four kinds of solvent extracts from three Chinese barley varieties (Ken-3, KA4B, and Gan-3) were used to examine the effects of extraction solvent mixtures on antioxidant activity evaluation and their extraction capacity and selectivity for free phenolic compounds in barley through free radical scavenging activity, reducing power and metal chelating activity, and individual and total phenolic contents. Results showed that extraction solvent mixtures had significant impacts on antioxidant activity estimation, as well as different extraction capacity and selectivity for free phenolic compounds in barley. The highest DPPH* and ABTS*+ scavenging activities and reducing power were found in 80% acetone extracts, whereas the strongest *OH scavenging activity, O2*- scavenging activity, and metal chelating activity were found in 80% ethanol, 80% methanol, and water extracts, respectively. Additionally, 80% acetone showed the highest extraction capacity for (+)-catechin and ferulic, caffeic, vanillic, and p-coumaric acids, 80% methanol for (-)-epicatechin and syringic acid, and water for protocatechuic and gallic acids. Furthermore, correlations analysis revealed that TPC, reducing power, DPPH* and ABTS*+ scavenging activities were well positively correlated with each other (p < 0.01). Thus, for routine screening of barley varieties with higher antioxidant activity, 80% acetone was recommended to extract free phenolic compounds from barley. DPPH* scavenging activity and ABTS*+ scavenging activity or reducing power could be used to assess barley antioxidant activity.  相似文献