Insecticidal efficacy of three vegetable oils as post-harvest grain protectants of stored wheat against Rhyzopertha dominica （F.） （Coleoptera： Bostrychidae）

The lesser grain borer, Rhyzopertha dominica is a major insect pests of stored grain in the tropics. Vegetable oils （chamomile, sweet almond and coconut） at 2.5, 3.5, 5.0, 7.0 and 10.0 mL/kg were tested against Rhyzopertha dominica （F.） in wheat grain. All bioassays were conductr, d at 30℃ and 65% ＋ 2% RH. Treatments with vegetable oils at high dose （10.0 mL/kg） achieved over 95% control within 24 h of exposure to freshly treated grain, There was little difference between the three oils in their effect. Persistence of oils in grains was tested at short-term storage intervals （48, 72 and 96 h） and intermediate-term intervals （10, 20 and 30 days） after treatments. The activity of all products decreased with storage period. Seed viability was reduced by the high dose rate （10.0 mL/kg） of oil treatments. The potential use of vegetable oils as supplementary or alternative grain protectants against insect damage in traditional grain storage in developing countries is discussed.     

Characterization of midgut trypsin-like enzymes and three trypsinogen cDNAs from the lesser grain borer, Rhyzopertha dominica (Coleoptera: Bostrichidae)

Protein digestion in the lesser grain borer, Rhyzopertha dominica (F.) (Coleoptera: Bostrichidae), results from the action of a complex of serine proteinases present in the midgut. In this study we partially characterized trypsin-like enzyme activity against N-α-benzoyl- -arginine p-nitroanilide (BApNA) in midgut preparations and cloned and sequenced three cDNAs for trypsinogen-like proteins. BApNAase activity in R. dominica midgut was significantly reduced by serine proteinase inhibitors and specific inhibitors of trypsin, whereas BApNAase activity was not sensitive to specific inhibitors of chymotrypsin or aspartic proteinases. However, trans-epoxysuccinyl- -leucylamido-(4-guanidino) butane (E-64) inhibited BApNAase activity by about 30%. BApNAase was most active in a broad pH range from about pH 7 to 9.5. The gut of R. dominica is a tubular tract approximately 2.5 mm in length. BApNAase activity was primarily located in the midgut region with about 1.5-fold more BApNAase activity in the anterior region compared to that in the posterior region. Proteinases with apparent molecular masses of 23–24 kDa that were visualized on casein zymograms following electrophoresis were inhibited by TLCK.Three cDNAs for trypsinogen-like proteins were cloned and sequenced from mRNA of R. dominica midgut. The full cDNA sequences consisted of open reading frames encoding 249, 293, and 255 amino acid residues for RdoT1, RdoT2, and RdoT3, respectively. cDNAs RdoT1, RdoT2, and RdoT3 shared 77–81% sequence identity. The three encoded trypsinogens shared 54–62% identity in their amino acid sequences and had 16–18 residues of signal peptides and 12–15 residues of activation peptides. The three predicted mature trypsin-like enzymes had molecular masses of 23.1, 28, and 23.8 kDa for RdoT1, RdoT2, and RdoT3, respectively. Typical features of these trypsin-like enzymes included the conserved N-terminal residues IVGG^62–65, the catalytic amino acid triad of serine proteinase active sites (His¹⁰⁹, Asp¹⁵⁶, Ser²⁵⁷), three pairs of conserved cysteine residues for disulfide bridges, and the three residues (Asp²⁵¹, Gly²⁷⁴, Gly²⁸⁴) that determine specificity in trypsin-like enzymes. In addition, RdoT2 has both a PEST-like sequence at the C-terminus and a free Cys¹⁵⁸ near the active site, suggesting instability of this enzyme and/or sensitivity to thiol reagents. The sequences have been deposited in GenBank database (accession numbers AF130840 for RdoT1, AF130841 for RdoT2, and AF130842 for RdoT3).     

Host odours enhance the responses of adult Rhyzopertha dominica to male-produced aggregation pheromone

The behavioural responses of adult male and female Rhyzopertha dominica (Coleoptera, Bostrichidae) to blends of host volatiles and male-produced aggregation pheromone were observed in a four-arm airflow olfactometer. The odour sources used were five pheromone-releasing males each on a single maize grain (lower maize-volatiles blend), five pheromone-releasing males on 500 g of maize (higher maize-volatiles blend) or the host volatiles emanating from 500g of maize (maize volatiles alone). Multiple-choice tests, in which volatiles from all three odour sources were presented in the exposure chamber at the same time, were used to study odour preferences of the males and females. Both sexes showed strongest attraction to the higher maize volatile blend but there were significant sex differences in response to the odour sources. Males spent significantly more time than females in the zone with only maize volatiles, and females spent significantly more time in the higher maize-volatiles zone. However, when odour sources were offered singly, females gave numerically greater responses than males to all sources although this difference was statistically significant for only the lower maize-volatiles blend. As males are more attracted than females to host odours alone it is suggested that they may be more highly adapted to seek out new hosts while females are more inclined to locate a food source by following the pheromone signals produced by males. However, both sexes responded most strongly to the odour source comprising aggregation pheromone with the higher proportion of maize volatiles.     

Characterization of an Aspartic Proteinase of Mucor pusillus expressed in Aspergillus oryzae

The aspartic proteinase (MPP) gene from the zygomycete fungus Mucor pusillus was introduced into an ascomycete fungus, Aspergillus oryzae, by protoplast transformation using the nitrate reductase (niaD) gene as the selective marker. Southern blot analysis indicated that the MPP gene was integrated into the resident niaD locus at a copy number of 1–2. MPP secreted by the recombinant A. oryzae was correctly processed but was more highly glycosylated than that produced in the original M. pusillus strain. Treatment with endo--N-acetyl-glucosaminidase H and analysis of the carbohydrate composition of the secreted MPP revealed that the extra glycosylation of the MPP secreted by the recombinant A. oryzae was due to altered processing of mannose residues. The extra glycosylation of MPP affected its enzyme properties including its milk-clotting and proteolytic activities.     

Parasitism by the mite Acarophenax lacunatus on beetle pests of stored products

Recent reports of the biocontrolpotential of the mite species Acarophenaxlacunatus (Cross & Krantz) (Prostigmata:Acarophenacidae) and the lack of biologicalstudies on this regulatory agent led to thepresent study carried out under laboratoryconditions. The objective of the investigationwas to assess the host range of A. lacunatus,so far only reported as egg parasite ofRhyzopertha dominica (F.) (Coleoptera:Bostrichidae). Four Coleoptera species ofstored cereals were used: R. dominica,Tribolium castaneum (Herbst) (Tenebrionidae),Cryptolestes ferrugineus (Stephens)(Laemophloeidae) and Oryzaephilus surinamensis (L.) (Cucujidae). The highest rates of eggparasitism were observed on R. dominica and T.castaneum, leading to a significant decrease ofpopulations of both species and reduced wheatweight loss. A. lacunatus was also able toparasitize eggs of C. ferrugineus, but not ofO. surinamensis. These results indicate abroader host range of A. lacunatus thaninitially suspected and also strengthen itspossibility of use in integrated pestmanagement programs in storage environments.     

Constituents of Musa balbisiana seeds and their activity against Cryptolestes pusillus

The chloroform and acetone extracts of the seeds of Musa balbisiana Colla (Musaceae) and four of its constituents were assayed in the diet for toxicity against the flat grain beetle (Cryptolestes pusillus Schöherr). A mixture of fatty esters of phytol and the flavan (+)-epiafzelechin showed a significant growth inhibition and toxicity against this economically important pest of stored cereals. The LD₅₀ was 6.3% for the most active compound, (+)-epiafzelechin.     

Antifungal effects of the volatile oils from Allium plants against Trichophyton species and synergism of the oils with ketoconazole

In an attempt to develop stable and safe antifungal agents from natural products (daily foodstuffs in particular), the activities of essential oils from Allium sativum for. pekinense, A. cepa, and A. fistulosum against three Trichophyton species responsible for severe mycoses in humans were investigated and compared with activity of allicin in this study. The fungistatic activities of Allium oils were evaluated by the broth dilution method and disk diffusion assay. The combined effects of Allium oils with ketoconazole were tested by the checkerboard titer test. Among the tested oils, A. sativum for. pekinense oil exhibited the strongest inhibition of growth of T. rubrum, T. erinacei, and T. soudanense with MICs (minimum inhibiting concentrations) of 64microg/ml, while the activities of A. cepa and A. fistulosum were relatively mild. The inhibiting activities of the oils on Sabouraud agar plates were dose dependent against Trichophyton species. Additionally, these oils showed significant synergistic antifungal activity when combined with ketoconazole in the checkerboard titer test and disk diffusion test.     

江苏沿江地区出口农产品仓储甲虫种类调查及检疫重要性分析

通过对江苏沿江地区出口农产品仓储甲虫调查,鉴定出仓储甲虫36个科115种,其中以皮蠹科、锯谷盗科、步甲科种类较多,均占6．96％。本文提出用选择性指数和适合性指数评价仓储甲虫的检疫重要性。据此将各种仓储甲虫划分为重要仓储害虫、较重要仓储害虫与次要仓储害虫三大类。     

Simulation of generation times of the rusty grain beetle,Cryptolestes ferrugineus, in farm-stored grain in the canadian prairies, 1952-1990

The number of potential annual generations of the rusty grain beetle,Cryptolestes ferrugineus, was simulated in wheat stored in granaries for all crop districts in the prairie provinces of Canada each year from 1952 to 1990 using a population dynamic model driven by ecological variables. Granary size was assumed to be 6 m in diameter. Historical data for temperatures at harvest and times when storage began were used in the simulation model. A second model, which predicted the rate of temperature change at the centre of a 6-m-diameter bulk of wheat, determined environmental parameters for the population dynamic model. (Grain moisture content was assumed constant at 14.5% wet mass basis.) The combined model shows that the initial storage temperature is the most important factor responsible for predicting the number of generations and levels of infestation ofC. ferrugineus. This finding was largely validated by historical grain storage and infestation data. For various years initial grain temperature ranged from 17.7 to 37.4 °C and harvest dates were between 1 August and 20 October. The number of generations annually in simulations based on field conditions ranged from 0.35 to 6.77 with a mean of 3.29. Three or more generations result in a severe infestation and every year at least three simulated generations were completed in some crop districts. In one year, at least three generations were completed in every crop district. Harvest temperature and date permit prediction of crop districts that will potentially have the largest populations of C.ferrugineus so that early monitoring of wheat for infestations can be targeted to areas most at risk. Cereal Research Centre Contribution No. 1660     

Plant development and synthesis of essential oils in micropropagated and mycorrhiza inoculated plants of Origanum vulgare L. ssp. hirtum (Link) Ietswaart

Biomass production of micropropagated oregano was induced by inoculation with the fungus Glomus viscosum. The effects of arbuscular mycorrhizal (AM) symbiosis on morphological and metabolic variations of regenerated oregano plants were investigated at different growth stages. AM greatly increased parameters such as plant leaf area, fresh and dry weight, number of spicasters and verticillasters in infected plants. An increase of the gland density, especially on the upper leaf epidermis, was also observed following the physiological ageing of the tissues. The in vitro plants of O. vulgare ssp. hirtum described in this study provided a qualitatively and quantitatively good source of essential oils that have a chemical profile comparable to that of the control mother plants with carvacrol as the main compound.     

Chemical composition and larvicidal effects of essential oil of Dendropanax morbifera against Aedes aegypti L.

Essential oils obtained from the flowers of Dendropanax morbifera were extracted and the chemical composition and larvicidal effects were studied. The analyses were conducted by gas chromatography and mass spectroscopy (GC–MS) revealed that the essential oil of D. morbifera contained 27 compounds. The major chemical components identified were γ-elemene (18.59%), tetramethyltricyclohydrocarbon (10.82%), β-selinene (10.41%), α-zingibirene (10.52%), 2-isopropyl-5-methylbicylodecen (4.2%), β-cubebene (4.19), and 2,6-bis(1,1-Dimethylethyl)-4-phenol (4.01%). The essential oil had a significant toxic effect against early fourth-stage larvae of Aedes aegypti L. with an LC₅₀ value of 62.32 ppm and an LC₉₀ value of 131.21 ppm. The results could be useful in search for newer, safer, and more effective natural larvicidal agents against A. aegypti.     

以CpG-ODN为佐剂的新型隐球菌疫苗研究

新型隐球菌感染尚无有效的预防手段。本文探讨以Cp G为佐剂开发抗新型隐球菌疫苗的可行性。将经新型隐球菌甘露糖蛋白(mannoprotein,MP)或/和Cp G-ODN刺激过的DCs经气管接种于实验鼠,检测支气管肺泡灌洗液(BALF)中IFN-γ的产生。将新型隐球菌接种于实验鼠气管内,取气管旁淋巴结细胞与经新型隐球菌MP(mannoprotein)或/和Cp G-ODN预处理过的DCs共培养,检测培养上清中IFN-γ的产生。结果显示,经MP刺激过的DCs共培养可诱导淋巴细胞产生IFN-γ。以MP为抗原,Cp G-ODN为佐剂的疫苗可以保护小鼠抵御新型隐球菌感染。本研究证实了隐球菌甘露糖蛋白MP通过DCs诱导了Th1型反应,并提示了以Cp G-ODN为佐剂基于MP制备新型隐球菌疫苗的可能性。     

模式植物短柄草研究新进展

短柄草(Brachypodium distachyon)株型矮小,易于种植栽培,生长周期短,自花授粉,容易繁殖。另外,短柄草基因组比较小,易于转化,与小麦具有比较近的亲缘关系,是理想的草类特别是禾本科模式植物。近年来,短柄草的研究工作在细胞遗传学、基因组学、比较基因组学、植物-病原菌相互作用、功能基因组学等研究领域取得了许多进展,包括完成了Bd-21全基因组的测序工作、构建了T-DNA插入突变体库、用遗传学的方法首次研究短柄草基因的生物学功能等。本文综述了近年来特别是2009年以来短柄草的研究进展,并对未来的研究工作做了展望。     

35S标记重组植物钙调素的制备方法

利用³⁵S标记的氨基酸混合物喂养工程菌,成功地制备了³⁵S标记的拟南芥钙调素亚型2（³⁵S-ACaM2）,对其纯度、放射活度、电泳行为及其灵敏性等进行了检测.结果表明从工程菌中制备的³⁵S-ACaM2纯度高、放射活度高、Ca²⁺与EGTA存在时的电泳行为与未标记的ACaM2相同,可作为一种高灵敏性的探针用于检测钙调素结合蛋白.     

Fumigant toxicity of the essential oils of some African plants against Anopheles gambiae sensu stricto

The essential oils from 15 species of African plants selected by ethnobotanical considerations and field inspection (odour and presence of insects) were screened for fumigant toxicity to Anopheles gambiae s.s. in the laboratory. Essential oils from 6 species showed varying levels of toxicity, with Conyza newii (Compositae) and Plectranthus marruboides (Labiateae) being the most potent. Fifty compounds representing approximately 74% of the essential oil of C. newii were identified by GC-MS and GC-coinjection (for available standards). The major and some of the minor constituents of the two oils were assayed at different doses. Two compounds, from C. newii, perillaldehyde and perillyl alcohol, exhibited higher fumigant toxicity (LD50 = 1.05 x 10(-4) and 2.52 x 10(-4) mg cm(-3), respectively) than the parent oil (2.0 x 10(-3) mg cm(-3)). GC-MS analysis of the essential oil of P. marruboides gave results similar to that previously reported. Interestingly, none of its components were active, suggesting that the insecticidal activity of the oil results from either some of the minor components or as a blend effect of some of the major constituents.     

黑果枸杞原生质体培养及植株再生

该研究以黑果枸杞(Lycium ruthenicum)无菌苗为材料,建立了愈伤组织来源的原生质体再生体系,采用ISSR和FCM技术对再生植株进行了遗传稳定性分析。结果表明：(1)黑果枸杞叶片愈伤组织是产生原生质体的最好材料,在含0.5 mg·mL^-1甘露醇的酶液中,继代1次的叶片愈伤组织中原生质体产量为7.77×10⁶个·g^-1,活力为92%。(2)改良MS培养基 固体液体双层培养(MS₂ 固液双层)是培养原生质体的最好方式,培养10 d的原生质体分裂频率为45.9%,培养20 d的细胞团形成频率为22.9%。(3)在1.5 mg·mL^-1 6 BA+0.1 mg·mL^-1 IBA+MS培养基中,叶片愈伤组织产生的原生质体可分化获得再生植株。(4)ISSR分析显示,再生植株的平均遗传相似系数为0.88;FCM显示再生植株为二倍体,与亲本植株一致。该研究结果为进一步研究枸杞体细胞杂交技术转移野生植物抗逆遗传性状提供科学依据,为枸杞优良品种的选育奠定了基础。     

Evaluation of the strains of Acinetobacter and Enterobacter as potential biocontrol agents against Ralstonia wilt of tomato

Bacterial wilt (Ralstonia solanacearum) of tomato, Lycopersicon esculentum, causes a considerable amount of damage to tomato in Southern China. Biological control is one of the more promising approaches to reduce the disease incidence and yield losses caused by this disease. Based on antagonistic activity against R. solanacearum and three soil-borne fungal pathogens as well as biocontrol efficacy in the greenhouse, two bacterial strains Xa6 (Acinetobacter sp.) and Xy3 (Enterobacter sp.) were selected out of fourteen candidates as potential biocontrol agents. In order to find a suitable antagonist inoculation method, we compared the methods of root-dipping with soil-drenching in the aspects including rhizocompetence, biocontrol efficacy, and effect of promoting plant growth under greenhouse conditions. The drenching treatment resulted in a higher biocontrol efficacy and plant-yield increase, and this method was also easier to operate in the field on a large scale. Field trials were conducted for further evaluation of these two antagonistic strains. In both greenhouse and field experiments, the strain Xy3 had a better control effect against bacterial wilt than Xa6 did, while Xa6 caused higher biomass or yield increases. As recorded on the 75th day after treatment in two field experiments, biocontrol efficacy of Xy3 was about 65% in both field trials, and the yield increases caused by Xa6 were 32.4 and 40.7%, respectively, in the two trials. This is the first report of an Acinetobacter sp. strain used as a BCA against Ralstonia wilt of tomato.     

萝卜-芥蓝异源四倍体植物SR30基因转录本的选择性剪接分析

为了解异源多倍体形成后,其剪接因子基因SR30在各组织器官间的表达量以及选择性剪接模式与亲本的差异,选取萝卜-芥蓝异源四倍体(Raphanobrassica)及其亲本萝卜(Raphanus sativus)、芥蓝(Brassica oleracea var.alboglabra)为材料,运用RACE-PCR方法克隆到全长的编码序列(CDS)和3非编码区(3 UTR),运用q RT-PCR和半定量RT-PCR检测其在各组织器官中的表达量和各转录本表达量间的差异。结果表明,四倍体中萝卜同源的Rs SR30基因有5种转录本,芥蓝同源的Bo SR30基因有4种转录本。同时,SR30在3物种中的表达具有组织器官的差异,且在四倍体中的总体表达量显著低于亲本。根据克隆到的转录本,预测Rs SR30编码3种蛋白,Bo SR30编码2种,不同蛋白异构体的区别体现在C末端的丝氨酸-精氨酸富集(RS)结构域。因此,萝卜-芥蓝异源多倍体形成后,SR30基因在表达量和转录本选择性剪接方面都发生了改变。     

纤维型植物南荻的生物学及其应用研究进展

南荻(Triarrhena lutarioriparia L.Liu)是我国特有高产纤维素型多年生草本植物,其独特的生态适应性、广泛的用途及其生产开发潜力已引起相关行业的高度关注。概述了南荻的资源分布、生物学特性、繁育栽培及应用的研究现状,并对其纤维素资源的应用进行了展望。