Effects of diosmin, a flavonoid glycoside in citrus fruits, on P-glycoprotein-mediated drug efflux in human intestinal Caco-2 cells

The effects of citrus flavonoids on P-glycoprotein (P-gp)-mediated drug efflux were examined in human intestinal Caco-2 cells. The cellular accumulation of rhodamine-123 was measured using 10 citrus flavonoids for preliminary screening. Among the flavonoids tested, diosmin significantly increased the accumulation of rhodamine-123 in Caco-2 cells. In the bidirectional transport of digoxin, diosmin increased the apical-to-basal (A-to-B) transport but decreased the basal-to-apical (B-to-A) transport in both concentration- and time-dependent manners. The digoxin transport ratio (B-A/A-B) was estimated to be 2.3 at a concentration of 50 microM of diosmin, which was significantly lower than the 15.2 found in the control. The apparent Ki values for P(app,A-B) and P(app,B-A) were 16.1 and 5.7 microM, respectively. These results demonstrated that diosmin effectively inhibited the P-gp-mediated efflux in Caco-2 cells. Diosmin is one of the main components in citrus fruits, and the intake of food supplements containing this compound may potentially increase the absorption of drugs able to act as P-gp substrates. The clinical relevance of this interaction should be further evaluated using in vivo experiments.     

Effect of the molecular mass and degree of substitution of oleoylchitosan on the structure, rheological properties, and formation of nanoparticles

Oleoylchitosans (O-chitosans), with different molecular masses and degrees of substitution (DS), were synthesized by reacting chitosan with oleoyl chloride. The FT-IR suggested the formation of an amide linkage between amino groups of chitosan and carboxyl groups of oleic acid. The viscosity of O-chitosan sharply increased with the increase of concentration, whereas that of unmodified chitosan rose only slightly. This increase was stronger as the increase of hydrophobicity (DS) and molecular mass of the polymer. The critical aggregation concentration (CAC) of O-chitosans with DS 5, 11, and 27% were 79.43, 31.6, 10 mg/L, respectively, and the CAC of samples with molecular masses of 20, 38, 300, and 1100 kDa were 50.1, 74.93, 125.9, and 630.9 mg/L, respectively. All of the O-chitosans could reduce surface tension slightly. Nanoparticles were prepared using an O/W emulsification method. Mean diameters of the polymeric amphiphilic nanoparticles of O-chitosans with DS 5 and 11% were around 327.4 and 275.3 nm, respectively.     

Inhibition of tumorigenesis in ApcMin/+ mice by a combination of (-)-epigallocatechin-3-gallate and fish oil

The effect of a combination of (-)-epigallocatechin-3-gallate (EGCG) with fish oil on intestinal tumorigenesis in Apc (Min/+) mice fed a high-fat diet was investigated in the present study. The combined treatment of EGCG and fish oil for 9 weeks reduced the tumor number by 53% as compared to controls while neither agent alone had a significant effect. Apoptosis was significantly increased in all treatment groups. beta-Catenin nuclear positivity in adenomas from the combination group was lower than control mice, implicating the modulation of Wnt signaling by the combination. Fish oil and the combination significantly reduced prostaglandin E 2 (PGE 2) levels in small intestinal tumors as compared to controls, suggesting modulation of aberrant arachidonic acid metabolism by fish oil. Akt phosphorylation in adenomas was significantly reduced in all treatment groups, which may have contributed to the observed increase in apoptosis. The results indicate that a combination of low doses of EGCG and fish oil can inhibit tumor multiplicity in Apc (Min/+) mice.     

Characterization of aerosols containing microcystin

Toxic blooms of cyanobacteria are ubiquitous in both freshwater and brackish water sources throughout the world. One class of cyanobacterial toxins, called microcystins, is cyclic peptides. In addition to ingestion and dermal, inhalation is a likely route of human exposure. A significant increase in reporting of minor symptoms, particularly respiratory symptoms was associated with exposure to higher levels of cyanobacteria during recreational activities. Algae cells, bacteria, and waterborne toxins can be aerosolized by a bubble-bursting process with a wind-driven white-capped wave mechanism. The purposes of this study were to: evaluate sampling and analysis techniques for microcystin aerosol, produce aerosol droplets containing microcystin in the laboratory, and deploy the sampling instruments in field studies. A high-volume impactor and an IOM filter sampler were tried first in the laboratory to collect droplets containing microcystins. Samples were extracted and analyzed for microcystin using an ELISA method. The laboratory study showed that cyanotoxins in water could be transferred to air via a bubble-bursting process. The droplets containing microcystins showed a bimodal size distribution with the mass median aerodynamic diameter (MMAD) of 1.4 and 27.8 mum. The sampling and analysis methods were successfully used in a pilot field study to measure microcystin aerosol in situ.     

Flumorph Is a Novel Fungicide That Disrupts Microfilament Organization in Phytophthora melonis

ABSTRACT The mechanism of the effects of flumorph (a novel fungicide) was investigated by analyzing alterations of hyphal morphology, cell wall deposition patterns, F-actin organization, and other organelles in Phytophthora melonis. Calcofluor white staining suggested that flumorph did not inhibit the synthesis of cell wall materials, but disturbed the polar deposition of newly synthesized cell wall materials during cystospore germination and hyphal growth. After exposure to flumorph, zoospores were able to switch into cystospores accompanied with the formation of a cell wall, whereas cystospores failed to induce the isotropic-polar switch and did not produce germ tubes but continued the isotropic growth phase. In flumorph-treated hyphae, the most characteristic change was the development of periodic swelling ("beaded" morphology) and the disruption of tip growth. Newly synthesized cell wall materials were deposited uniformly throughout the diffuse expanded region of hyphae, in contrast to their normal polarized patterns of deposition. These alterations were the result of F-actin disruption, identified with the fluorescein isothiocynate (FITC)-phalloidin staining. The disruption of F-actin also was accompanied by disorganized organelles: each swelling of subapical hyphae was associated with a nucleus. Vesicles did not undergo polarized secretion to the apical hyphae, but diffused around nuclei for the subapical growth; thus, the cell wall was thickened with periodic expansion along the hyphae. Upon removing flumorph, normal tip growth and organized F-actin were observed again. These data, as well as data published earlier, suggest that flumorph may be involved in the impairment of cell polar growth through directly or indirectly disrupting the organization of F-actin. The primary site of action by flumorph in the disruption of the F-actin organization is under investigation.     

间伐强度对长白落叶松人工林冠层结构和草本物种多样性的影响

以吉林省临江林业局长白落叶松人工林为研究对象,分析不同林分蓄积、间伐强度、冠层结构和林下光环境对草本物种组成及物种多样性的影响。结果表明：随着间伐强度的增加,叶面积指数显著降低,冠层开度显著升高。各处理与对照相比,草本植物重要值大于1%的物种分别增多了12.50%、56.25%和50.00%,35%间伐强度的处理草本物种多样性最高。林下光辐射指标与叶面积指数呈显著负相关(P<0.05),与冠层开度呈显著正相关(P<0.05); Shannon-Wiener多样性指数、Simpson多样性指数与叶面积指数呈显著负相关(P<0.05)。间伐能明显增加长白落叶松人工林下草本物种多样性,建议间伐强度不宜超过35%。     

外源过氧化氢对水曲柳体胚发生中外植体抗氧化生理特性的影响

为了探讨外源过氧化氢（H₂O₂）对水曲柳体胚发生过程中外植体内部抗氧化物质、抗氧化酶、一氧化氮（NO）等的影响,以成熟水曲柳子叶胚为外植体诱导体胚发生,通过对体胚发生过程中不同时间段的外植体取材,测定其内部生理变化,分析外源H₂O₂对水曲柳内部生理生化的影响。结果表明：外源H₂O₂的添加,对水曲柳体胚发生过程中还原性抗坏血酸（ASA）的质量摩尔浓度的影响主要在中后期阶段（42 d）,且H₂O₂添加组高于对照组2.14%,对还原性谷胱甘肽（GSH）的影响在前期阶段（14 d）,H₂O₂添加组是对照组的3.23倍;外源H₂O₂处理提高外植体H₂O₂的质量摩尔浓度,在14 d时,外源H₂O₂处理和对照的H₂O₂     

宜昌早春大棚厚皮甜瓜品种的筛选

为选择适宜宜昌地区早春大棚种植的厚皮甜瓜（Cucumis melo）品种,选择了7个厚皮甜瓜品种与种植面积较广的长江蜜魁进行品种比较试验,通过对生物学性状、果实品质及产量等指标的调查分析,从中选出综合性状表现良好的品种。结果表明,参试品种众天8号产量较高,生育期适中,口感爽脆,抗病性较强,有较强的推广价值;七彩脆蜜因其果肉独特,口感爽脆,有一定的推广价值。     

榆林山地苹果简易化快速整形修剪技术研究

近年来,榆林大力发展山地苹果,集中连片栽植,规模较大,为进一步培养树形,提高果实产量,本试验以长富2号、烟富3和瑞雪为试材,研究简易化快速整形修剪技术,对果树栽后第二年、第三年冬剪连续两年抹光杆（保留中央领导干延长头）,调查其五年生树体生长量和2015-2019年产量。结果表明：采用二年抹光杆修剪技术,能够显著提高幼树生长势,加快树形培养;长富2号五年生干径较对照增粗2.03cm,分枝数较对照增加5.7个,枝干比较对照降低0.36,中短枝比例显著增加,短枝比例较对照升高19.7%。2019年（九年生）长富2号产量1 815.7 kg/667 m²,较对照增收1 309.2 kg,2015-2019年累计产量为5 323.7kg,较对照增加3 438.0 kg,每年较对照平均增产687.6 kg,增产效果显著。