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【目的】桃果实易受匍枝根霉(Rhizopus stolonifer)侵染引起软腐病,导致果实采后腐烂损失严重。目前人工合成的化学杀菌剂是控制桃果实采后病害的主要方法,但长期使用容易带来食品安全隐患、病原菌抗药性和环境污染等问题。通过研究生物源抑菌成分1-辛烯-3-醇对桃果实软腐病的控制作用,为减少化学农药使用和控制采后桃果实软腐病提供理论基础。【方法】使用1-辛烯-3-醇熏蒸接种匍枝根霉(R.stolonifer)后的桃果实,对果实抗病相关基因表达和酶活性进行测定。通过离体试验,研究1-辛烯-3-醇熏蒸对匍枝根霉(R.stolonifer)菌丝和孢子的影响。【结果】55.80μg/mL 1-辛烯-3-醇熏蒸处理可以显著降低桃果实的发病率和病斑直径(P<0.05),提高几丁质酶(chitinase,CHI)和β-1,3葡聚糖酶(β-1,3-glucanase,GLU)的活性以及病程相关基因非表达子1(nonexpressor of pathogenesis-related protein 1,NPR1)、病程相关蛋白1(pathogenesis-related protein 1,PR1)、CHIGLU的基因表达量。离体试验结果显示,1-辛烯-3-醇可抑制平板上匍枝根霉(R.stolonifer)菌丝的生长,使菌丝体细胞结构遭到破坏,同时显著降低麦角固醇含量(P<0.05),抑制孢囊孢子的萌发和芽管伸长,并通过破坏孢子的膜结构,引起活性氧(reactive oxygen species,ROS)暴发与线粒体损伤。【结论】以上结果证实,1-辛烯-3-醇熏蒸处理不仅能直接破坏匍枝根霉(R.stolonifer)的菌丝与孢子,还可通过诱导桃果实的系统获得性抗性(systemic acquired resistance,SAR)抑制采后软腐病的蔓延。  相似文献   

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Intermittent exposure during a period of 3 weeks of undamaged Arabidopsis plants to trace amounts of volatiles emitted by freshly damaged Arabidopsis plants resulted in an increase of subsequent artificial-damage-induced production of (Z)-3-hexen-1-yl acetate and (Z)-3-hexen-1-ol in the exposed Arabidopsis plants when compared with Arabidopsis plants exposed to undamaged Arabidopsis plant volatiles (control plants). We previously showed that (Z)-3-hexen-1-yl acetate attracts a parasitic wasp, Cotesia glomerata. Thus, the induced production of this volatile explained our previously reported finding that, when artificially damaged, the exposed plants were more attractive to C. glomerata than control plants.  相似文献   

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Plasmodium falciparum, the major causative parasite for the disease, has acquired resistance to most of the antimalarial drugs used today, presenting an immediate need for new antimalarial drugs. Here, we report the in vitro and in vivo antimalarial activities of 6-(1,2,6,7-tetraoxaspiro[7.11]nonadec-4-yl)hexan-1-ol (N-251) against P. falciparum and Plasmodium berghei parasites. The N-251 showed high antimalarial potencies both in the in vitro and the in vivo tests (EC50 2.3 × 10−8 M; ED50 15 mg/kg (per oral)). The potencies were similar to that of artemisinin in vitro and greater than artemisinin's activity in vivo (p.o.). In addition, N-251 has little toxicity: a single oral administration at 2000 mg/kg to a rat gave no health problems to it. Administration of N-251 to mice bearing 1% of parasitemia (per oral 68 mg/kg, 3 times a day for 3 consecutive days) resulted in a dramatic decrease in the parasitemia: all the 5 mice given N-251 were cured without any recurrence, with no diarrhea or weight loss occurring in the 60 days of experiment. N-251 deserves more extensive clinical evaluation, desirably including future trials in the human.  相似文献   

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记述采自中国东北地区棘虫兆科滨棘虫兆族Thalassaphorurini1新种:宋氏异棘虫兆Allonyc hiurus songi sp.nov.及1新记录种:利富滨棘虫兆Thalassaphorura lifouensis(Thibaud&Weiner,1997),附详细描述及特征图。研究标本保存于中国科学院东北地理与农业生态研究所湿地生态与环境重点实验室。  相似文献   

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The biocatalytic reduction of 4-(trimethylsilyl)-3-butyn-2-one to enantiopure (R)-4-(trimethylsilyl)-3-butyn-2-ol was successfully conducted with high enantioselectivity using immobilized whole cells of a novel strain Acetobacter sp. CCTCC M209061, newly isolated from kefir. Compared with other microorganisms that were investigated, Acetobacter sp. CCTCC M209061 was shown to be more effective for the bioreduction reaction, and afforded much higher yield and product enantiomeric excess (e.e.). The optimal buffer pH, co-substrate concentration, reaction temperature, substrate concentration and shaking rate were 5.0, 130.6 mM, 30 °C, 6.0 mM and 180 r/min, respectively. Under the optimized conditions, the maximum yield and the product e.e. were 71% and >99%, respectively, which are much higher than those reported previously. Additionally, the established biocatalytic system proved to be efficient for the bioreduction of acetyltrimethylsilane to (R)-1-trimethylsilylethanol with excellent yield and product e.e. The immobilized cells manifested a good operational stability under the above reaction conditions since they retained 70% of their catalytic activity after ten cycles of use.  相似文献   

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In this paper, 20 kinds of different 2-(α-arylamino phosphonate)-chitosan (2-α-AAPCS) were prepared by different Schiff bases of chitosan (CS) reacted with di-alkyl phosphite in benzene solution. The structures of the derivatives (2-α-AAPCS) were characterized by FT-IR spectroscopy and elemental analysis. In addition, the antifungal activities of the derivatives against four kinds of fungi were evaluated in the experiment. The results indicated that all the prepared 2-α-AAPCS had a significant inhibiting effect on the investigated fungi when the derivatives concentration ranged from 50 to 500 μg mL−1. Furthermore, the antifungal activities of the derivatives increased with increasing the molecular weight and concentration. And the antifungal activities of the derivatives were affected by their dimensional effect and charge density. Besides, the rule and mechanism of the antifungal activities of them were discussed in this paper.  相似文献   

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The crude product of deamination of the commercially available -homoserine was acetylated and the 2-O-acetyl-3-deoxy- -glycero-tetronolactone (18) formed was used to N-acylate methyl perosaminide (methyl 4-amino-4,6-dideoxy-α- -mannopyranoside, 12) and its 2,3-O-isopropylidene derivative. The major product isolated from the reaction was the crystalline methyl 4-(4-O-acetyl-3-deoxy- -glycero-tetronamido)-4,6-dideoxy-α- -mannopyranoside (1, 70–75%) resulting from acetyl group migration in the initially formed 2'-O-acetyl derivative. O-Deacetylation of 1 gave the title amide 2. Compound 2, obtained crystalline for the first time, was fully characterized, and its crystal structure was determined. Deoxytetronamido derivatives diastereomeric with 1 and 2, respectively, were obtained by the acylation of 12 with 2-O-acetyl-3-deoxy- -glycero-tetronolactone (prepared from -homoserine), and subsequent deacetylation. Structures of several byproducts of the reaction of 12 with 18 have been deduced from their spectral characteristics. Since these byproducts were various O-acetyl derivatives of 2, the title compound could be obtained in ≈ 90% yield by deacetylating (Zemplén) the crude mixture of N-acylation products, followed by chromatography.  相似文献   

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A novel microbial method of synthesizing (S)-1-phenyl-1,3-propanediol [(S)-PPD] was developed in this study. Our laboratory stock cultures were screened for microorganisms that stereospecifically produced (S)-PPD from 3-hydroxy-1-phenylpropane-1-one (HPPO) using an intact cell system. Of the 828 strains examined (321 bacteria, 233 yeasts and 274 molds), certain strains of Williopsis saturnus var. mrakii and Cryptococcus albidus were found to produce (S)-PPD with over 99% enantiomeric excess (e.e.). Screening identified W. saturnus var. mrakii AJ-5620 as the most productive strain, and this strain was used for further experiments. The (S)-PPD-producing reaction using intact W. saturnus var. mrakii AJ-5620 cells was carried out by successive feeding of HPPO. A total (S)-PPD yield of 9.9 g/l was produced in 20 h. The molar yield was 81% and the optical purity of the (S)-PPD produced was over 99% e.e.  相似文献   

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Bidding Customs and Habitat Improvement for Matsutake (Tricholoma matsutake) in Japan. A brief history of Japan’s matsutake production, use, and management is presented, with emphasis on habitat improvement efforts and the land use tradition of iriai. Bidding systems for allotment of matsutake gathering rights are discussed. Three villages with different bidding systems are compared to see what effects the bidding systems have on village finances, matsutake production, and matsutake habitat enhancement. Contrary to expectations, habitat for matsutake was not improved when land owners were guaranteed the gathering and selling rights to matsutake growing on their own lands. Instead, habitat improvement was most successful and matsutake production was highest on community-owned lands in Oka Village, where the iriai tradition is strongest.  相似文献   

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The flight behavior of Anopheles gambiae s.s. Giles and An. stephensi Patton exposed to different odor cues was studied in a wind tunnel. Odors consisted of CO2, CO2 + acetone (at two concentrations), and CO2 + 1-octen-3-ol. Mosquitoes were released singly and their behavior was recorded on video. Parameters studied included flight velocity, percentage of time spent flying, percentage of time spent in plume, and number of turns toward the plume. Large differences in behavior toward the odors tested were observed. An. gambiaedid not respond well to CO 2,whereas An. stephansiwas positively affected by this compound. In contrast, An. gambiaeresponded significantly to CO 2 + acetone (at a low concentration), but the behavior of An. stephensiwas completely suppressed by this combination of odor stimuli. CO 2 + a high concentration of acetone or CO 2 + 1-octen-3-ol did not cause significant effects in An. gambiaecompared to no odor, while these treatments elicited strong behavioral responses in An. stephensi.The latter species responded particularly well to CO 2 + 1-octen-3-ol. The results suggest that the observed differences may be inherent to the known differences in host preferences, where An. gambiaeis highly anthropophilic and An. stephensimore zoophilic. This would explain why the latter species responds well to CO 2 and even better to CO 2 + 1-octen-3-ol, a compound readily emitted by bovine ruminants.  相似文献   

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Abstract The application aspects of chemicals which attract the forest cockchafer, Melolontha hippocastani F., were investigated in field and laboratory experiments. Previous studies have shown that males of M. hippocastani are attracted by a synthetic mixture of green leaf volatiles (GLV) and the sex pheromone 1,4‐benzoquinone (BQ), that synergistically enhances the male response to GLV. In the present study, we demonstrated that BQ also synergised the male response to one single component of the GLV mixture, the leaf alcohol (Z)‐3‐hexen‐1‐ol (Z‐3‐ol). BQ enhanced the attractiveness of Z‐3‐ol at doses between 0.05 and 5 mg per trap, reaching a maximum at 5 × 10?1 mg day?1. The addition of an insecticide (cyhalothrin) to traps baited with BQ and Z‐3‐ol did not affect the lures’ attractiveness. However, when a conidiospore formulation of the entomopathogenic fungus Beauveria brongniartii (Saccardo) Petch was added, the attractiveness of baited traps was significantly reduced. Furthermore, two types of dispensers baited with a solution of BQ in Z‐3‐ol at 20 mg ml?1 were tested over the entire 4‐week flight season. Both a membrane dispenser and a dispenser based on a porous polyethylene (PPE) absorbent disk attracted more males than controls over the entire 4 weeks. The membrane dispenser attracted as many males each week as a reference formulation that was renewed daily. Furthermore, the membrane dispenser attracted more males than the PPE dispenser in weeks 2–4, although laboratory experiments showed that the latter released even higher or at least equal amounts of the joined lure over the entire 4 weeks. However, estimation of the BQ/Z‐3‐ol ratios of the released material by solid phase microextraction (SPME) and coupled gas chromatography–mass spectrometry (GC‐MS) revealed that the membrane dispenser released a higher proportion of BQ than the PPE dispenser in weeks 2–4. Therefore, a higher BQ/Z‐3‐ol ratio might be responsible for the advantage of the membrane dispenser in the field.  相似文献   

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The (1-->3)-beta-D-pentaglucoside was synthesized as its (R)-2,3-epoxypropyl glycoside via 2+3 strategy. The disaccharide donor 8 was obtained by 3-selective coupling of 2 with 4, followed by deallylation, and trichloroacetimidation. Meanwhile, the trisaccharide acceptor 12 was prepared by coupling of 10 with 4, followed by deacetylation. Condensation of 8 with 12, followed by epoxidation, and deprotection, gave the target pentaoside. The results of these bioassays demonstrated that the (1-->3)-beta-D-glucanase was obviously inactivated by 15 with k(app)=3.79 x 10(-4) min(-1). At the same time, we found that the 15 was more active as compared to the laminaripentaose in eliciting phytoalexin accumulation in tobacco cotyledon tissue, and it could be kept longer time than laminaripentaose, which indicated it is much more stable than laminaripentaose.  相似文献   

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Small molecules that exhibit biological activity have contributed to the understanding of the molecular mechanisms of various biological phenomena. 5-Bromodeoxyuridine (BrdU) is a thymidine analogue that modulates various biological phenomena such as cellular differentiation and cellular senescence in cultured mammalian cells. Although BrdU is thought to function through changing chromatin structure and gene expression, its precise molecular mechanisms are not understood. To study the molecular mechanism for the action of BrdU, we have employed the yeast Saccharomycescerevisiae as a model system, and screened multi-copy suppressor genes that confer resistance to BrdU. Our genetic screen has revealed that expression of the N-terminal short fragment of TUP1, and also disruption of HDA1 or HOS1, histone deacetylases that interact with TUP1, conferred resistance to BrdU. These results suggest the implication of the chromatin proteins in the function of BrdU, and would provide novel clues to answer the old question of how BrdU modulates various biological phenomena.  相似文献   

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Vibrio cholerae O1 and V. cholerae non-O1 strains isolated from environmental samples collected in São Paulo, Brazil, during cholera epidemics and pre-epidemic periods were examined for the presence of toxin genes. V. cholerae O1 strains isolated from clinical samples in Peru and Mexico, and V. cholerae O139 strains from India were also examined for the presence of ctx (cholera toxin gene) and zot (zonula occludens toxin gene) by polymerase chain reaction (PCR). A modified DNA-extraction method applied in this study yielded satisfactory recovery of genomic DNA from vibrios. Results showed that strains of V. cholerae O1 isolated during the preepidemic period were ctx -/zot - whereas strains isolated during the epidemic were ctx +/zot +. All V. cholerae non-O1 strains tested in the study were ctx -/zot -, whereas all V. cholerae O139 strains were ctx +/zot +. Rapid detection of the virulence genes (ctx and zot) can be achieved by PCR and this can serve as an important tool in the epidemiology and surveillance of V. cholerae.  相似文献   

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