An in vitro study on the postinfection activities of copper hydroxide and copper sulfate against conidia of Venturia inaequalis

The postinfection activities of copper hydroxide [Cu(OH)2] and copper sulfate (CuSO4) against apple scab (Venturia inaequalis) were evaluated in an in vitro study. Our intention was to support the aim of reducing copper application rates by appropriate timing of applications. Experiments were conducted at 20 degrees C with leaf disks and isolated cuticular membranes (CM) of Malus x domestica 'Gloster' and 'Elstar'. Conidia of V. inaequalis were used as the inoculum. In untreated controls, 7.9 and 33.2% of germinated conidia formed primary stromata 24 and 48 h after inoculation, respectively. Treatments with copper compounds were applied 24 and 48 h after inoculation, which was 16 and 40 h after infection had occurred. When working with CM and using fluorescein diacetate as a vital stain, vital and dead stromata could be distinguished. Treatment effects were assessed 72 h after inoculation by counting vital (fluorescing) primary stromata. With leaf disks, the number of stromata was counted using KOH-aniline blue fluorescence staining. Cu(OH)2 and CuSO4 showed postinfection activity and killed primary stromata, provided that the surface of the CM was kept wet. Cu(OH)2 was more effective than CuSO4 and was able to kill all primary stromata 24 h after inoculation at concentrations of 116 and 231 mg L(-1). When Cu(OH)2 was applied at 116 mg L(-1) to leaf disks 24 h after inoculation, the number of primary stromata did not significantly differ from the control. Results indicate different modes of action for the highly water soluble CuSO4 and the slightly soluble Cu(OH)2. This supports the hypothesis that spore exudates react with insoluble copper compounds and form highly toxic copper complexes. Application of Cu(OH)2 to dry CM did not kill primary stromata. Hence, for Cu(OH)2 to exert postinfection activity, leaves must be wet. In the field, this cannot be guaranteed and a postinfection application of Cu(OH)2 cannot be recommended.     

Anti-inflammatory effects of resveratrol and oligostilbenes from Vitis thunbergii var. taiwaniana against lipopolysaccharide-induced arthritis

Vitis thunbergii Sieb. and Zucc. var. taiwaniana Lu is an endemic plant in Taiwan used as a dietary supplement for bone health. In this study, human chondrocytes were induced to produce COX-2, MMP-3, -13, and PGE(2) by LPS. An (18)F-FDG microPET imaging system was used to evaluate the anti-inflammatory arthritic effects in vivo. Six stilbenes, resveratrol (1), (+)-ε-viniferin (2), ampelopsin C (3), ampelopsin A (4), (-)-vitisin B (5), and (+)-vitisin A (6), were isolated from the stem part of V. thunbergii, which displayed the strongest PGE(2) inhibition. Among these compounds, 1 significantly decreased COX-2 activity, PGE(2), MMP-3, and -13 production in vitro, and (18)F-FDG uptake and serum PGE(2) in rabbits in vivo. Anti-inflammatory effects were enhanced through the combined usage of 1 and other oligostilbenes. Taken together, the synergistic effects of 1 and oligostilbenes resulted in stem part extracts with lower 1 content displaying the better anti-inflammatory arthritis effects.     

Method for the quantitative extraction of resveratrol and piceid isomers in grape berry skins. Effect of powdery mildew on the stilbene content

A simple method for the quantitative extraction of resveratrol and its glycosides from grape berry skins has been developed. Optimal conditions for the extraction were investigated. Type of solvent, time, and temperature assayed influenced resveratrol and piceid yield. Adequate extraction was attained with ethanol/water (80:20 v/v) maintained at 60 degrees C for 30 min. Recovery (>96%) and reproducibility (6.83-15.13%) were satisfactory. After extraction, resveratrol and piceid isomers were quantified by high-performance liquid chromatography coupled to a ultraviolet-visible diode array detector. The amounts detected in 13 samples of 7 different varieties analyzed were, on average, 92.33 microg/g of dry skin for cis-piceid, 42.19 microg/g of dry skin for trans-piceid, and 24.06 microg/g of dry skin for trans-resveratrol. cis-Resveratrol was not detected in any sample. In grape berries infected by powdery mildew the contentw of these compounds were considerably increased and the degree of infection was positively related to their stilbene content.     

Pinolide, a new nonenolide produced by Didymella pinodes , the causal agent of ascochyta blight on Pisum sativum

An aggressive isolate of Didymella pinodes isolated from pea ( Pisum sativum ) produced four different metabolites in vitro. The metabolites isolated from the culture filtrates were characterized by spectroscopic and optical methods. A new nonenolide, named pinolide, was isolated and characterized as (2S*,7R*,8S*,5E,9R*)-2,7,8-trihydroxy-9-propyl-5-nonen-9-olide. Pinolidoxin, the main toxin produced by D. pinodes, was also isolated together with two other closely related nonenolides, identified as herbarumin II and 2-epi-herbarumin II. Herbarumin II and 2-epi-herbarumin II have been previously isolated from the fungi Phoma herbarum and Paraphaeosphaeria recurvifoliae , respectively, but described here to be isolated for the first time from D. pinodes. When tested on leaves of the host plant and other legumes and weeds, pinolidoxin was phytotoxic in all of the plant species, whereas the other three nonenolides did not produce any symptoms. The importance of the stereochemistry of the hydroxy group at C-7 on phytotoxicity also is discussed.     

一种茶树促生菌固化剂的研制及其施用效果

为了提高茶园土壤有效养分含量和促生菌的定殖效率,以茶园土壤和茶树生长特性为条件,筛选耐酸铝和养分转化效率较高的菌株,再通过固定化技术,获得固定化促生菌剂,以游离态菌液为对照,通过田间试验比较菌株的土壤定殖、土壤微生物区系和土壤养分状况。试验筛选出一株红酵母菌属的菌株(Rhodotorula sp.)命名为WYS2。通过固化技术(0.25%活性炭吸附2%菌体后,用1%海藻酸钠+2%琼脂包埋)制作的促生菌固化菌剂,在与有机肥施用40 d后促生菌WYS2在土壤定殖效率较游离态菌悬液提高293倍。同时在0～20 cm土层中,与不施用菌株WYS2处理和施用游离态WYS2菌悬液处理相比,固定化WYS2菌剂处理的土壤碱解氮含量增加了23.4%～39.8%,速效钾含量增加了18.1%～25.1%,铵态氮含量增加了36.4%～45.1%。因此,认为利用筛选出的促生红酵母菌WYS2结合固定化技术使用后可有效提高其土壤定殖效率,同时促进茶园土壤碱解氮、速效钾和铵态氮等速效养分含量的增加。     

Evaluation of the antioxidant capacity of limonin, nomilin, and limonin glucoside

The antioxidant capacity (AOC) of three representative citrus limonoids, limonin, nomilin, and limonin glucoside, was examined by the oxygen radical absorbance capacity (ORAC), Trolox equivalent antioxidant capacity (TEAC), beta-carotene-linoleic acid bleaching, and 1,1-diphenyl-2-picryl hydrazyl (DPPH) radical scavenging assays. Pure compounds and proper negative (cinnamic acid) and positive (2,6-di-tert-butyl-4-methylphenol (BHT) and ascorbic acid) controls were used to remove any ambiguity in interpreting results. In all cases, limonin and nomilin gave results equivalent to those of cinnamic acid, indicating that they do not possess any inherent AOC and should not be considered antioxidants. Similar results were observed for limonin glucoside, with the exception of an anomalous result obtained from the beta-carotene-linoleic acid bleaching assay. Limonin glucoside was deemed not to be an antioxidant on the basis of the three unequivocal assays.     

Structure-activity relationship and mechanism of the tocopherol-regenerating activity of resveratrol and its analogues

The present study investigated the mechanism of the synergistic antioxidant activity of alpha-tocopherol with resveratrol (3,5,4'-trihydroxy-trans-stilbene, 3,5,4'-THS) and its synthetic analogues, that is, 3,4-dihydroxy-trans-stilbene (3,4-DHS), 4,4'-dihydroxy-trans-stilbene (4,4'-DHS), 4-hydroxy-trans-stilbene (4-HS), and 3,5-dihydroxy-trans-stilbene (3,5-DHS). The reaction kinetics of alpha-tocopheroxyl radical with resveratrol and its analogues were studied in sodium dodecyl sulfate (SDS) and cetyl trimethylammonium bromide (CTAB) micelles using the stopped-flow electron paramagnetic resonance (EPR) technique. It was found that resveratrol and its analogues could regenerate alpha-tocopherol with rate constants (k(REG)) in the order of 3,4-DHS > 4,4'-DHS > resveratrol > or = 4-HS > or = 3,5-DHS in SDS and CTAB micelles. It was found that the analogues bearing o-dihydroxyl groups (3,4-DHS) and p-dihydroxyl groups (4,4'-HS) exhibited remarkably higher alpha-tocopherol-regenerating activity than those bearing no such groups (resveratrol, 4-HS, and 3,5-DHS). In addition, the alpha-tocopherol-regenerating activity of resveratrol and its analogues was correlated with their electrochemical behaviors, suggesting that electron transfer might play a critical role during the regeneration reaction.     

Botrytone, a new naphthalenone pentaketide produced by Botrytis fabae, the causal agent of chocolate spot disease on Vicia faba

A strain of Botrytis fabae isolated from faba bean (Vicia faba L.) plants displaying clear chocolate spot disease symptoms produced phytotoxic metabolites in vitro. The phytotoxins isolated from the culture filtrate organic extract were characterized by spectroscopic and optical methods. A new naphthalenone pentaketide, named botrytone, was isolated and characterized as (4R)-3,4-dihydro-4,5,8-trihydroxy-1(2H)-naphthalenone together with other well-known closely related naphthalenones such as regiolone and cis- and trans-3,4-dihydro-2,4,8-trihydroxynaphthalen-1(2H)-ones. When tested on leaves of the host plant, with the cis- and trans-3,4-dihydro-2,4,8-trihydroxynaphthalen-1(2H)-ones assayed in mixture, regiolone demonstrated the highest level of phytotoxicity together with cis- and trans-3,4-dihydro-2,4,8-trihydroxynaphthalen-1(2H)-ones. Botrytone showed moderate phytotoxic activity at 1 mg/mL and was still phytotoxic at 0.5 mg/mL.     

Cellular and behavioral effects of stilbene resveratrol analogues: implications for reducing the deleterious effects of aging

Research suggests that polyphenolic compounds contained in fruits and vegetables that are rich in color may have potent antioxidant and anti-inflammatory activities. The present studies determined if stilbene (e.g., resveratrol) compounds would be efficacious in reversing the deleterious effects of aging in 19 month old Fischer 344 rats. Experiment I utilized resveratrol and six resveratrol analogues and examined their efficacies in preventing dopamine-induced decrements in calcium clearance following oxotremorine-induced depolarization in COS-7 cells transfected with M1 muscarinic receptors (MAChR) that we have shown previously to be sensitive to oxidative stressors. Experiment II utilized the most efficacious analogue (pterostilbene) from experiment I and fed aged rats a diet with a low (0.004%) or a high (0.016%) concentration of pterostilbene. Results indicated that pterostilbene was effective in reversing cognitive behavioral deficits, as well as dopamine release, and working memory was correlated with pterostilbene levels in the hippocampus.     

Physiological effects of extraction juices from apple, grape, and red beet pomaces in rats

In comparison to classical fruit juice processing, polyphenols and dietary fiber can be extracted from pomace by means of pectinases and cellulases. In the present study, rats were fed with such produced extraction juices from apples, grapes, and red beets as drinking fluids instead of water for 4 weeks to evaluate their physiological effects. In all test groups, the intake of extraction juices was greater as compared to control (water intake), resulting in a higher urine excretion. In the apple and grape group, pH values in feces was lower than control. Administration of extraction juices from apples increased fecal counts of Lactobacillus and Bifidobacterium. More acetate and total short-chain fatty acids appeared in intestinal contents of the apple and red beet group. Furthermore, the intestinal contents of test groups contained higher concentrations of primary bile acids, cholesterol, and cholesterol metabolites but lower concentrations of secondary bile acids. The total amount of steroids excreted by these groups was also greater than control. Quercetin and isorhamnetin appeared in urine of rats fed extraction juices from apples and grapes; in urine of the former group, phloretin was found also. Administration of the extraction juices, enriched in secondary plant metabolites and dietary fiber, resulted in beneficial nutritional effects in rats.     

A rapid diagnostic assay for detection and quantification of the causal agent of strawberry wilt from field samples

Verticillium dahliae Kleb, the cause of Verticillium wilt disease, is a destructive pathogen that leads to severe yield losses in strawberry fields and thus considerable economic damages. Although rapid identification and detection methods are becoming available more, pathogen quantification remains one of the main challenges in the disease management. In this study, a real-time polymerase chain reaction (rtPCR) assay was developed to quantitatively assess V. dahliae abundance directly from affected roots and soil collected from different areas in Estonia. A specific primer pair based on the ribosomal DNA (rDNA) internally transcribed spacer was designed for SYBR Green-based assay. Strawberry plant and soil samples were randomly collected from different areas in Estonia and analyzed for V. dahliae by soil plating technique and rtPCR assay. The assay was specific for V. dahliae so that the minimum detection limit was 0.93?pg?µl^?1 of pathogen DNA and the lowest amount of V. dahliae detected in soil was 10.48?pg?µl^?1 of target DNA corresponding to one microsclerotia per gram of soil. This technique allowed rapid detection and quantification of the pathogen DNA at the picogram level in soils and even in symptomless plants, facilitating the screening of the pathogen in diverse areas. This is the first study about the rtPCR technique being used successfully to assess populations of V. dahliae with high specificity and sensitivity in Estonia strawberry fields. Results of this research can be useful for growers and agricultural organizations to improve available disease management strategies against Verticillium wilt.     

Antioxidant activity and inhibition of alpha-glucosidase by trans-resveratrol, piceid, and a novel trans-stilbene from the roots of Israeli Rumex bucephalophorus L

The roots of Rumex bucephalophorus, collected in Israel, were analyzed for trans-stilbenes. Two stilbene-O-glycosyl derivatives were identified, in addition to 3,5,4'-trihydroxystilbene (1) (resveratrol). The stilbene-O-glycosyl derivatives were 5,4'-dihydroxystilbene-3-O-beta-d-glucopyranoside (2) (piceid) and the new 5,4'-dihydroxystilbene-3-O-alpha-arabinopyranoside (3), which is being named rumexoid. The structure of rumexoid was elucidated by using spectroscopic data. The antioxidant capacities of stilbenoids 1-3 were determined and expressed as trolox equivalent antioxidant capacity (TEAC). TEAC value for trans-resveratrol was highest (2.7) and for rumexoid lowest (1.5). In vitro, trans-resveratrol and rumexoid demonstrated a potent inhibitory effect on alpha-glucosidase activity (IC50 < 0.1 and < 0.5 mM, respectively). The commercial antidiabetic agent acarbose was shown to inhibit only 35% of the enzyme activity at 0.5 mM. The addition of piceid to the reaction mixture did not inhibit alpha-glucosidase in vitro in the range of concentrations used. These findings extend the range of reported beneficial effects of stilbene derivatives, and demonstrate the multifaceted activities that dietary polyphenols may exert in the intestine, where their concentrations are highest in the body.     

Sequestering ability of butylated hydroxytoluene,propyl gallate,resveratrol, and vitamins C and E against ABTS,DPPH, and hydroxyl free radicals in chemical and biological systems

The antioxidant capacity of butylated hydroxytoluene (BHT; 2,6-di-tert-butyl-p-cresol), propyl gallate (3,4,5-trihydroxybenzoic acid n-propyl ester), resveratrol (trans-3,4',5-trihydroxystilbene), and vitamins C (l-ascorbic acid) and E [(+)-alpha-tocopherol] was studied in chemical and biological systems. The chemical assays evaluated the capacity of these antioxidants to sequester 2,2'-azinobis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS.) and 1,1 diphenyl-2-picrylhydrazyl (DPPH.). A new colorimetric method to determine hydroxyl radical scavenging is also described. The biological tests use the eucaryotic cells of Saccharomyces cerevisiae treated with the antioxidants in the presence of the stressing agents apomorphine, hydrogen peroxide, and paraquat dichloride (methylviologen; 1,1'-dimethyl-4,4'-bipyridinium dichloride). The results in chemical systems showed that all of the antioxidants were able to significantly inhibit the oxidation of beta-carotene by hydroxyl free radicals. The assays in yeast showed that the antioxidant activity of the tested compounds depended on the stressing agent used and the mechanism of action of the antioxidant.     

苹果汁金属膜和纸板过滤除菌效果比较

该文进行了金属膜和纸板过滤的苹果汁除菌效果的比较。结果表明,金属膜过滤前后果汁的色值变化差异不大,试验中色值降低的最大值为2%;纸板过滤的果汁色值差异较大,试验中色值降低的最小值为7%;金属膜与纸板过滤对浊度的影响都很显著,试验中浊度降低的最小值分别为70%和48%;0.05 μm的金属膜和纸板过滤两者均能达到除菌要求。金属膜过滤得到的果汁品质优于纸板过滤,使用成本比纸板过滤也低,金属膜又具有耐酸、耐碱、抗氯、耐高温、耐高压的优良特性,具有代替纸板过滤的广阔应用前景。     

Protective effects of Chinese propolis and its component, chrysin, against neuronal cell death via inhibition of mitochondrial apoptosis pathway in SH-SY5Y cells

Endoplasmic reticulum (ER) stress has been implicated in the pathogenesis of neurodegenerative and ischemic disorders. The purpose of this study was to evaluate the effects of Chinese propolis and its constituents [chrysin, galangin, pinocembrin, caffeic acid, and caffeic acid phenethyl ester (CAPE)] against tunicamycin-induced neuronal cell death in SH-SY5Y cells. Both Chinese propolis and chrysin concentration-dependently inhibited such cell death, the tunicamycin-induced activation of caspase-3, and the effects of tunicamycin on mitochondria [release of cytochrome c into the cytosol and disruption of the mitochondrial membrane potential (DeltaPsim)]. Furthermore, Chinese propolis and chrysin each inhibited staurosporine-induced cell death. These findings indicate that the inhibitory effects of Chinese propolis against neuronal cell death induced by ER stress or staurosporine may be exerted primarily by chrysin. Moreover, the mechanism underlying the protective effects may, at least partly, involve inhibitions of caspase-3 activity and the mitochondrial apoptotic pathway.     

Anticarcinogenic effects of glycoalkaloids from potatoes against human cervical, liver, lymphoma, and stomach cancer cells

Methods were devised for the isolation of large amounts of pure alpha-chaconine and alpha-solanine from Dejima potatoes and for the extraction and analysis of total glycoalkaloids from five fresh potato varieties (Dejima, Jowon, Sumi, Toya, and Vora Valley). These compounds were then evaluated in experiments using a tetrazolium microculture (MTT) assay to assess the anticarcinogenic effects of (a) the isolated pure glycoalkaloids separately, (b) artificial mixtures of the two glycoalkaloids, and (c) the total glycoalkaloids isolated from each of the five potato varieties. All samples tested reduced the numbers of the following human cell lines: cervical (HeLa), liver (HepG2), lymphoma (U937), stomach (AGS and KATO III) cancer cells and normal liver (Chang) cells. The results show that (a) the effects of the glycoalkaloids were concentration dependent in the range of 0.1-10 mug/mL (0.117-11.7 nmol/mL); (b) alpha-chaconine was more active than was alpha-solanine; (c) some mixtures exhibited synergistic effects, whereas other produced additive ones; (d) the different cancer cells varied in their susceptibilities to destruction; and (e) the destruction of normal liver cells was generally lower than that of cancer liver cells. The decreases in cell populations were also observed visually by reversed-phase microscopy. The results complement related observations on the anticarcinogenic potential of food ingredients.     

Evaluation of Malus species and cultivars at the Fruit Genebank Dresden-Pillnitz and its use for apple resistance breeding

Using the results of evaluation of Malus accessions during the last 20 years more than 15 new resistant apple cultivars were selected. The breeding aim was the combination of different kinds of resistance with good fruit quality. The best of these cultivars enclose resistance against Venturia inaequalis, Podosphaera leucotricha, Erwinia amylovora, Pseudomonas syringae, Panonychus ulmi and winterfrost. Different scab resistance sources (Vf, Vr, VA) found among the Malus species are combined in the most recent breeding lines.The new resistant Pillnitz apple cultivars ('Recultivars®') guarantee the possibility to reduce 80% and more of fungicide spraying in fruit growing and are very suitable for ecological and integrated fruit production. Four of these, 'Reanda', 'Rebella', 'Remo' and 'Rewena', are triple resistant to scab, mildew and fire blight and are good donors for breeding multiple resistance.     

Synthesis of a combinatorial library of amides and its evaluation against the fall armyworm, Spodoptera frugiperda

The fall armyworm Spodoptera frugiperda is a polyphagous pest that causes important damage in different regions of America and mainly affects corn crops in both tropical and subtropical areas. Currently, control relies on both transgenic plants and/or chemical pesticides. In this work we describe the preparation of an indexed combinatorial library of amides and its toxic effect by contact against S. frugiperda . (E)-1-(1-Piperidinyl)-3-[4-(trifluoromethoxy)phenyl]-2-propen-1-one was the most active compound with an LD(50) = 0.793 μg mg(-1) of larva. This amide was also evaluated by ingestion and at the lowest concentration (1 mg kg(-1)) achieved 83.3% mortality.     

苹果幼果发育期果柄结构和Ca、Mg、K水平的变化

以富士、金冠苹果树为试材,分析了同一花序不同部位的果实重量,Ca、Mg、K含量和果柄结构的变化,以期探讨果柄发育和幼果Ca、Mg、K吸收之间的关系及其在幼果脱落中的作用。结果表明,随幼果的发育,单个幼果重量和Ca、Mg、K含量呈增加趋势;与发育不正常的边果相比,发育正常的中心果和边果的鲜重、干重、果柄直径、维管束数目、木质部厚度、韧皮部维管束面积和单果Ca、Mg、K总含量较高,而以干重为单位的果柄Ca、Mg含量较低。相关分析表明,苹果幼果的单果重和Ca、Mg、K含量与果柄的直径、维管束数目、木质部厚度、韧皮部维管束面积呈显著正相关,说明幼果发育与Ca、Mg、K吸收和果柄结构密切相关,Ca、Mg、K吸收率低和果柄发育不良可能是导致落果的重要原因。     

生长模型和15N示踪评价施肥处理对苹果树氮肥利用的影响

为提高果树氮肥利用率,探索一种简便易行的氮肥利用评价方法,该研究以田间5年生延长红（“长富2号”芽变品种）为研究对象,分别采用生长模型和15N示踪技术对比分析不施氮肥（CK）、常规高氮（N800,800 kg/hm2化肥氮）、优化减氮（N400,400 kg/hm2化肥氮）和有机无机配施（N200+O200,化肥氮和有机氮各200 kg/hm2）处理下苹果树对氮肥的吸收利用情况以及各器官氮素的分配特性的差异,结果表明：不同施肥处理对苹果的产量没有显著性的影响（31.7～37.3 t/hm2）;各施氮处理基于生长模型和15N示踪技术的果树氮肥利用率分别为13.13%～31.94%和11.64%～32.40%;基于生长模型,N400和N200+O200处理果树的氮肥利用率比N800处理高84.92%和143.26%;基于15N示踪技术,N200+O200处理的果树氮肥利用率比N800和N400高178.35%和69.28%;不同施肥处理对各器官氮素分配没有显著性的影响。两种评价方法对于果实和叶片的氮肥利用率、各器官氮素的分配情况分别存在显著差异（P<0.05）和极显著差异（P<0.01）,但对植株总体氮肥利用率的评价结果无显著差异,平均仅相差3.10%。基于本试验的研究结果可以得出,利用生长模型可以估算苹果树的氮肥利用率。研究结果可为农田管理措施改善以及果树氮肥利用率评价提供理论参考。