Lipoxygenase inhibitory activity of anacardic acids     

Ha TJ  Kubo I 《Journal of agricultural and food chemistry》2005,53(11):4350-4354

6[8'(Z)-pentadecenyl]salicylic acid, otherwise known as anacardic acid (C15:1), inhibited the linoleic acid peroxidation catalyzed by soybean lipoxygenase-1 (EC 1.13.11.12, type 1) with an IC50 of 6.8 microM. The inhibition of the enzyme by anacardic acid (C15:1) is a slow and reversible reaction without residual activity. The inhibition kinetics analyzed by Dixon plots indicates that anacardic acid (C15:1) is a competitive inhibitor and the inhibition constant, KI, was obtained as 2.8 microM. Although anacardic acid (C15:1) inhibited the linoleic acid peroxidation without being oxidized, 6[8'(Z),11'(Z)-pentadecadienyl]salicylic acid, otherwise known as anacardic acid (C15:2), was dioxygenated at low concentrations as a substrate. In addition, anacardic acid (C15:2) was also found to exhibit time-dependent inhibition of lipoxygenase-1. The alk(en)yl side chain of anacardic acids is essential to elicit the inhibitory activity. However, the hydrophobic interaction alone is not enough because cardanol (C15:1), which possesses the same side chain as anacardic acid (C15:1), acted neither as a substrate nor as an inhibitor.  相似文献   

The structure and receptor binding properties of the 1918 influenza hemagglutinin   总被引：1，自引：0，他引：1  

Gamblin SJ  Haire LF  Russell RJ  Stevens DJ  Xiao B  Ha Y  Vasisht N  Steinhauer DA  Daniels RS  Elliot A  Wiley DC  Skehel JJ 《Science (New York, N.Y.)》2004,303(5665):1838-1842

The 1918 influenza pandemic resulted in about 20 million deaths. This enormous impact, coupled with renewed interest in emerging infections, makes characterization of the virus involved a priority. Receptor binding, the initial event in virus infection, is a major determinant of virus transmissibility that, for influenza viruses, is mediated by the hemagglutinin (HA) membrane glycoprotein. We have determined the crystal structures of the HA from the 1918 virus and two closely related HAs in complex with receptor analogs. They explain how the 1918 HA, while retaining receptor binding site amino acids characteristic of an avian precursor HA, is able to bind human receptors and how, as a consequence, the virus was able to spread in the human population.  相似文献   

Fluorescence-force spectroscopy maps two-dimensional reaction landscape of the holliday junction     

Hohng S  Zhou R  Nahas MK  Yu J  Schulten K  Lilley DM  Ha T 《Science (New York, N.Y.)》2007,318(5848):279-283

Despite the recent advances in single-molecule manipulation techniques, purely mechanical approaches cannot detect subtle conformational changes in the biologically important regime of weak forces. We developed a hybrid scheme combining force and fluorescence that allowed us to examine the effect of subpiconewton forces on the nanometer scale motion of the Holliday junction (HJ) at 100-hertz bandwidth. The HJ is an exquisitely sensitive force sensor whose force response is amplified with an increase in its arm lengths, demonstrating a lever-arm effect at the nanometer-length scale. Mechanical interrogation of the HJ in three different directions helped elucidate the structures of the transient species populated during its conformational changes. This method of mapping two-dimensional reaction landscapes at low forces is readily applicable to other nucleic acid systems and their interactions with proteins and enzymes.  相似文献   

一种做为遗传学教学的实验材料——卤虫     

张强  孔祥祯  哈米提  丁勇 《新疆农业大学学报》1993,(4)

卤虫做为一种经济动物已广泛应用于水产养殖业中,但是做为一种遗传学教学的实验材料尚无人报道过。通过多次实验,本文作者提出了一种改进后的观察卤虫染色体形态和数目的实验方法。同时,作者还例举了各种事实表明卤虫是一种很好的遗传学教学的实验材料。  相似文献   

绿农素对杀虫剂防治效果的影响     

王景怀哈德卿  董家行刘强郑维莲  王恩民 《天津农林科技》2005,(5):5-7

为了确定绿农素对杀虫剂防治效果的影响,通过田间小区试验,对供试作物田间虫害发生情况进行了全面考察.结果表明：在降低杀虫剂施药量的前提下,绿农素能够增强杀虫剂的防治效果,降低蔬菜中有害物质残留,可在无公害蔬菜生产上应用推广.  相似文献   

T－黄平菇主要生物学特性研究     

李明  哈保茹  张杏楼  冯贺敬 《河北农业大学学报》1995,(3)

试验设不同培养基、不同温度、不同ｐＨ值３种处理，研究其对Ｔ－黄平菇菌丝生长的影响。同时对生料袋栽Ｔ－黄平菇的出菇时间及产量进行了试验。结果表明，Ｔ－黄平菇菌丝在ＰＤＡ培养基上生长最为适宜；在２６℃～２８℃条件下菌丝生长最佳；菌丝生长的最适ＰＨ值为６　～８。袋栽结果表明，Ｔ－黄平菇耐高温、出菇早、子实体形美色艳，是较好的高温型平菇品种之一．  相似文献   

The stress of weaning influences serum levels of acute-phase proteins, iron-binding proteins, inflammatory cytokines, cortisol, and leukocyte subsets in Holstein calves   总被引：1，自引：0，他引：1  

Myung-Hoo Kim  Ji-Young Yang  Santi Devi Upadhaya  Hyun-Jun Lee  Cheol-Heui Yun  Jong K. Ha 《Journal of veterinary science (Suw?n-si, Korea)》2011,12(2):151-157

The purpose of our study was to investigate changes in immunological parameters induced by weaning stress (including milk restriction) in calves. Fifteen Holstein calves were subjected to weaning at 6 weeks of age. Blood samples were collected at -14, -7, -2, 1, 3, and 5 days post-weaning (DPW; 0 DPW = 42 days). Weaning caused significant (p < 0.01) increases in the neutrophil (NE):lymphocyte (LY) ratio at 5 DPW with a significant (p < 0.05) reduction of LYs. The concentration of acute-phase proteins (haptoglobin and serum amyloid A) also increased significantly (p < 0.05) at 3 and 5 DPW compared to -2 DPW. Levels of the iron-binding protein lactoferrin decreased significantly (p < 0.05) after weaning. Serum tumor necrosis factor-α and cortisol levels were elevated (p < 0.05) at 3 DPW, while those of serum interferon-γ decreased (p < 0.05) at 1 and 3 DPW compared to levels observed before weaning. Weaning significantly (p < 0.05) decreased the percentage of CD25⁺ T cells in the peripheral blood. In conclusion, weaning stress affected the NE:LY ratio along with the levels of acute phase proteins, lactoferrin, cortisol, and inflammatory cytokines in the peripheral blood of calves. Weaning stress may induce an acute phase response possibly through the elevation of cortisol production and modulation of inflammatory cytokines.  相似文献   

Lipoxygenase inhibitory activity of octyl gallate   总被引：2，自引：0，他引：2  

Ha TJ  Nihei K  Kubo I 《Journal of agricultural and food chemistry》2004,52(10):3177-3181

Octyl gallate inhibited soybean lipoxygenase-1 (EC 1.13.11.12, type I) with an IC(50) of 1.3 microM. The inhibition of the enzyme by octyl gallate is a slow and reversible reaction without residual activity. The inhibition kinetics analyzed by Lineweaver-Burk plots indicates that octyl gallate is a competitive inhibitor, and the inhibition constant, K(I), was obtained as 0.54 microM. One molecule of octyl gallate scavenged six molecules of 1,1-diphenyl-2-picrylhydrazyl and inhibited autoxidative lipid peroxidation. In addition, octyl gallate was effective in preventing lipid peroxidation.  相似文献   

Methylation methods for the quantitative analysis of conjugated linoleic acid (CLA) isomers in various lipid samples   总被引：8，自引：0，他引：8  

Park SJ  Park CW  Kim SJ  Kim JK  Kim YR  Park KA  Kim JO  Ha YL 《Journal of agricultural and food chemistry》2002,50(5):989-996

Precise methylation methods for various chemical forms of conjugated linoleic acid (CLA), which minimize the formation of t,t isomers and allylmethoxy derivatives (AMD) with the completion of methylation, were developed using a 50 mg lipid sample, 3 mL of 1.0 N H(2)SO(4)/methanol, and/or 3 mL of 20% tetramethylguanidine (TMG)/methanol solution(s). Free CLA (FCLA) was methylated with 1.0 N H(2)SO(4)/methanol (55 degrees C, 5 min). CLA esterified in safflower oil (CLA-SO) was methylated with 20% TMG/methanol (100 degrees C, 5 min), whereas CLA esterified in phospholipid (CLA-PL) was methylated with 20% TMG/methanol (100 degrees C, 10 min), followed by an additional reaction with 1.0 N H(2)SO(4)/methanol (55 degrees C, 5 min). Similarly, CLA esterified in egg yolk lipid (CLA-EYL) was methylated by base hydrolysis, followed by reaction with 1.0 N H(2)SO(4)/methanol (55 degrees C, 5 min). These results suggest that for the quantitative analysis of CLA in lipid samples by GC, proper methylation methods should be chosen on the basis of the chemical forms of CLA in samples.  相似文献   

Anthropogenic Input of Selected Heavy Metals (Cu, Cr, Pb, Zn and Cd) in the Aquatic Sediments of Hochiminh City, Vietnam     

Hoang Thi Thanh Thuy  Nguyen Nhu Ha Vy  Tu Thi Cam Loan 《Water, air, and soil pollution》2007,182(1-4):73-81

The aquatic system of Hochiminh City comprises two main rivers: the Sai Gon and Nha Be rivers. Five canals discharge into these two rivers: NhieuLoc-ThiNghe, TauHu-BenNghe, TanHoa-LoGom, ThamLuong-BenCat and Doi-Te. The rivers and these canals collect effluent water from domestic and industrial sources. Most of these flows are not treated or at most are only primarily treated. A total of 33 sediment cores were taken from these rivers and canals. Chemical composition of these aquatic sediments has very high concentrations of several “urban” metals such as Cd, Cr, Cu and Zn. Most of the samples have exceeded the US EPA’s toxicity reference values for Cu, Zn and Cr (82, 82 and 70%, respectively). The highest concentrations of these metals appear to be associated with the uncontrolled and untreated industrial runoff to the discharge canals. These concentrations in fluvial sediment are relatively low, which indicates the dilution process of the contaminants. This finding indicates that the anthropogenic inputs play an important role in the elevation of heavy metals in the aquatic system and organic matter seems to exert a strong geochemical control on the amount of heavy metals. The Pearson correlation coefficients calculated for Cd, Cr, Cu and Zn, are 0.89; 0.72; 0.93 and 0.87, respectively.  相似文献