飞虱虫疫霉的产孢生物学研究

飞虱虫疫霉Erynia delphacis (Hori) 是水稻害虫稻褐飞虱的天敌,在田间常造成流行病,使大量褐飞虱死亡。在研究利用真菌防治害虫方面,一个很重要的问题就是如何在人工培养基上培养病原菌,并获得大量可以保存的孢子然后用于田间。本试验的重点在于用液体培养的方法获得这种菌的分生孢子,并测定了液体和固体培养的产孢量和产孢时间。     

A novel computerised image analysis method for the measurement of production of conidia from the aphid pathogenic fungus Erynia neoaphidis

A semi-automated method has been developed for the quantification and measurement of conidia discharged by the aphid pathogen Erynia neoaphidis. This was used to compare conidiation by E. neoaphidis-mycosed pea aphid cadavers, mycelial plugs cut from agar plates, mycelial pellets from shake flasks and by mycelial pellets from different phases of liquid batch fermenter culture. Aphid cadavers discharged significantly more and significantly smaller conidia than plugs or pellets. The volume of conidia discharged was stable over the period of discharge (80 h), but more detailed analysis of the size frequency distribution showed that more very small and very large conidia were discharged after 5 h incubation than after 75 h incubation. Biomass harvested at the end of the exponential growth phase in batch fermenter culture produced significantly more conidia than biomass from any other growth phase. The implications of these findings for the development of production and formulation processes for E. neoaphidis as a biological control agent are discussed.     

Production Factors Involved in the Formulation of Erynia neoaphidis as Alginate Granules

Granular formulations of the aphid-pathogenic fungus Erynia neoaphidis were produced by entrapping mycelia in alginate polysaccharide polymers. Four Swiss isolates were compared for the numbers of conidia discharged from the surface of alginate granules in standardized laboratory assays and two were considered to be suitable for further development. Conidiation was achieved from granules produced using nozzle diameters of 2.0. 1.0 and 0.5 mm from glass burettes or a novel vibrating tip apparatus. The mean diameters of dried granules varied from 0.5 to 1.8 mm. The addition of sucrose, potato starch or chitin in alginate solutions significantly improved the numbers of discharged conidia. W ith freshly produced granules, there was a 14.2- fold increase in sporulation from 6.3 to 89.7 conidia mm - 2 using 2% (w/v) sucrose. Increases of 1.6-to 2.3-fold, from 11.0 to 17.7 and 25.2 conidia mm - 2, were observed using 5% (w/v) starch or chitin respectively. The overnight drying of granules in a laminar flow hood and storage for 4 days at 4 C made differences in sporulation more obvious. There was a 15.5-fold difference in conidial numbers of 12.4 and 0.8 conidia mm - 2 from granules with and without sucrose respectively. For starch and chitin, there were 76.0-and 46.5-fold increases from 0.4 to 30.4 and 18.6 conidia mm - 2respectively. Fresh or dried alginate granules containing 2% sucrose and 5% starch gave 8.6-26.6% infection in laboratory bioassays with nymphs of pea aphid, Acyrthosiphon pisum , which were not significantly different when compared with infections of 6.7-22.9% using agar cultures or unsupplemented granules. Further studies on desiccation and storage regimes are required in order to improve the short-term shelf-life of E. neoaphidis alginate granules.     

Influence of Flight and Colour Morph on Susceptibility of Sitobion avenae to Infection by Erynia neoaphidis

The influence of clone and morph on the infection of Sitobion avenae with Erynia neoaphidis was examined in laboratory assays. The LC 50 -values were low; green alates: 0.8-1.8, green apterae: 2.9, brown alates: 1.5 and brown apterae: 2.6-3.6 conidia mm -2 . Within each of the two inoculation occasions, alates of both clones were significantly more susceptible than apterae, while there was no difference between the two clones. The LT 50 -values at 18°C varied between 6.4 and 7.5 days and there was no significant difference in LT 50 -values between either the two different coloured clones or between alates and apterae.     

植物油对虫霉菌液体培养与保存的作用*

在萨氏营养液（ＳＤＢ）中加入用 ０．１％蔗糖脂肪酸酯－１５（ＳＥ１５）乳化的０．５０％芝麻油,可使在ＳＤＢ中生长慢而结块的新蚜虫疠霉、安徽虫瘟霉、飞虱虫疠毒和根虫瘟霉等四种虫霉的五个菌株形成均匀分散的菌丝体和能稳定转接的菌液。在ＳＤＢ中加入乳化芝麻油 （ ０．２５％～１．５％）、菜籽油（ ０．５０％～１．５％）和色拉油（ ８０％花生油和 ２０％菜籽油,０．７５％～１．５％）,能明显提高新蚜虫疠霉Ｆ９８０１８的生物量;而在ＳＤＢ中加入０．５０％乳化芝麻油,可使液培菌丝产孢量增加近一倍;在ＳＤＢ中加入的三种植物油（０．７５％）,在Ｆ９８０１８生长４ｄ后,含量分别下降了８５％～９４％,但其中脂肪酸相对组成基本不变,表明该菌生长能充分利用植物油中各脂肪酸。用萨氏培养基（ ＳＤＡＹ）、加入 ０．５０％乳化芝麻油的 ＳＤＡＹ（ ＯＳ－ＳＤＡＹ）和牛奶蛋黄培养基（ＳＥＭＡ）培养安徽虫瘟霉Ｆ９７０２８和新蚜虫疠霉Ｆ９８０２８,两菌株在ＳＥＭＡ上生长最快;在ＯＳ－ＳＤＡＹ以较慢速度正常生长;而在ＳＤＡＹ上,两菌株或不能生长,或在第二次培养时出现明显退化。用ＳＥＭＡ和ＯＳ－ＳＤＡＹ在３℃下来保存上述四种虫霉的七个菌株,在ＯＳ－ＳＤＡＹ上?     

Effect of oleic acid on vegetative growth of the aphid-pathogenic fungus Erynia neoaphidis

Abstract The aphid-pathogenic fungus Erynia neophidis grew on a semi-defined medium containing 16 g·1⁻¹ glucose, 3 g·1⁻¹ yeast extract and 5 g·1⁻ mycological peptone only when the medium was supplemented with low concentrations of certain fatty acids. Of these, oleic acid fulfilled the growth requirement at a concentration of 0.02% (v/v), but higher concentrations were toxic, causing complete loss of viability of cultures at a concentration of 0.2% (v/v) in liquid medium and at 4% (v/v) on solid medium. The reduced viability of the fungus in liquid culture compared to that on equivalent solid medium, and at low inoculum density compared to high inoculum density in liquid medium, is explicable in terms of this toxicity.     

引起害虫大规模流行病的两种虫霉

我国南方重要害虫松大蚜及茶尺蠖中近年来分别发现由加拿大虫疫霉和圆孢虫疫霉造成的大面积流行病,在短期内将害虫种群摧毁殆尽。加拿大虫疫霉系我国首次记载。本文描述和讨论了2种虫生真菌的形态特征,记载了真菌病的流行概况。     

Targeted Dispersal of the Aphid Pathogenic Fungus Erynia neoaphidis by the Aphid Predator Coccinella septempunctata

The potential of adult and larval C. septempunctata to vector the aphid-specific entomopathogenic fungus E. neoaphidis was assessed through a series of laboratory and field experiments. The ability of coccinellids to vector conidia from a colony of E. neoaphidis -infected pea aphids, Acyrthosiphon pisum, to a colony of uninfected A. pisum was demonstrated in a laboratory study. Adult coccinellids which had previously foraged on plants infested with different densities of sporulating cadavers (1, 5, 15, 30 cadavers per plant) initiated infection in a proportion of uninfected pea aphids (4, 0, 2 and 8%, respectively) when subsequently allowed to forage on A. pisum infested bean plants. Further laboratory studies demonstrated that fourth instar larvae and adult coccinellids artificially inoculated with conidia initiated infection in 11 and 13% of an A. pisum population in which they foraged, respectively. Furthermore, a proportion of A. pisum placed on bean plants which had previously been foraged on by inoculated larval and adult coccinellids also died from infection (3 and 10% of A. pisum, respectively). However, although coccinellid adults inoculated with conidia initiated infection in 19% of A. pisum, cereal aphids, S. avenae , exposed to the inoculated coccinellids did not become infected. A further laboratory study demonstrated that infection of A. pisum only occurred if inoculated coccinellids were transferred to A. pisum populations immediately post inoculation. However, a proportion of A. pisum placed on bean plants which had been foraged on by inoculated coccinellids transferred 0, 4 and 24 h post inoculation died from infection (9, 3 and 7%, respectively). A field study further demonstrated the potential of coccinellids to vector E. neoaphidis. Single spring sown field bean plants (Long Hoos Experimental Plots, IACRRothamsted Farm) were enclosed within nylon mesh bags and 25 adult A. pisum were added to each bag with one of the following treatments: no further addition (control), coccinellid adult (control), inoculated coccinellid adult, inoculated A. pisum or sporulating A. pisum cadavers. No aphids died of E. neoaphidis in the control treatments; 5, 16 and 33% of aphids were infected with E. neoaphidis on the other treatments, respectively.     

沫蝉的病原真菌新种——巨孢虫疫霉(英文)

在浙江省百山祖自然保护区虫生真菌调查中发现松树上的菱沫蝉(Agrophora sp.)的新病原真菌一种,因其分生孢子远大于任何已知种虫疫霉,故定为新种巨孢虫疫霉(Eryniagigantea Li,Chert et Xu)。其初生分生孢子长倒拟卵形或拟纺锤形,对称或略弯曲,42.6—76.7×l 2.3—26.0μm(平均57.6×l 8.6μm),长径比2.2—4.9(平均3.1);顶稍圆或尖削;基部乳突略钝,有时有孢领。次生分生孢子倒拟卵形至广倒拟卵形;毛管分生孢子未见。假根成束。假囊状体及休眠孢子未见。     

An Analysis of the Nutritional Requirements for Fatty Acids of Paramecium aurelia

SYNOPSIS. Axenically cultivated Paramecium aurelia , stock 299, required a fatty acid for growth. This need was satisfied by oleic acid and oleic acid-containing lipids. These included: TEM-4T (tartaric acid esters of tallow monoglycerides), certain phospholipids (crude as well as highly purified preparations), Tween 80, 85, Span 80 and glyceryl monoleate. High concentrations of oleic acid in the medium inhibited growth. This inhibition was partially released or annulled by certain mixtures of "non essential" fatty acids or by increasing the stigmasterol content of the growth medium. Definite but non-stoichiometric levels of oleic acid and sterol were required for optimal growth. Tween 60, a non-ionic emulsifier similar in its surfactant properties to Tween 80, stimulated growth in the presence of suboptimal amounts of oleic acid but failed itself to replace oleic acid as a growth requirement.     

虫疫霉属新种和中国新记录

本文报道了虫疫霉属2个新种及1个中国新记录种。新种北虫疫霉(Eryniaborea Fan et Li sp.nov.)发生于西北及东北地区的丽蝇成虫体上,菜叶蜂虫疫霉(Eryniaathaliae Li et Fan sp.nov)发生于陕西杨陵的黄翅菜叶蜂幼虫;新记录种近藤虫疫霉(Erynia kondoiensis Milner)发生于福州的烟蚜虫体上。本文详细描述了新种的形态。     

Effect of amylose content on the lipids of mature rice grain

Most of the nonstarch lipids in brown rice (Oryza sativa) of three rices differing in amylose content were contributed by bran, germ, polish and subaleurone layer. Nonstarch lipids consisted of 82–91% neutral lipids (of which 73–82% were triglycerides), 7–10% phospholipids and 2–8% glycolipids. Linoleic, oleic and palmitic acids were the major fatty acids. Nonwaxy (24 and 29% amylose) milled rice had proportionally more starch lipids and less nonstarch lipids than waxy (2% amylose) milled rice. Starch lipids were mainly lysophosphatidyl choline, lysophosphatidyl ethanolamine and free fatty acids. The major fatty acids were palmitic and linoleic acids, followed by oleic acid.     

Effects of 20 fungicides on the infectivity of conidia of the aphid entomopathogenic fungus Erynia neoaphidis

The effect of 20 fungicides on theinfectivity of conidia of the entomopathogenicfungus, Erynia neoaphidis, were assessedin the laboratory. After projection on broadbean leaves, conidia were treated withfungicides applied at their recommended fieldrate. Afterwards, the infectivity of theseinocula was assessed using an aphid bioassay.Four fungicides, carbendazim, kresoxym-methyl, nuarimol and thiophanate-methyl reduced the infectivity of the conidia by less than 25% and can be considered harmless for this aphid pathogen. Propiconazole was a little more toxic, with 37% reduction. Other products reducedinfectivity by between 50% and 100%. These are, from the least to the most toxic:flutriafol, prochloraz, epoxyconazole,iprodione, hexaconazole, triadimenol,azoxystrobine, cyproconazole, cyprodynil,flusilazole and tridemorph. Chlorothalonil,fenpropimorph, spiroxamine and tebuconazoletotally inhibited infectivity of the fungi. Analysis of the results according to chemicalclass showed that the benzimidazoles were theleast toxic for E. neoaphidis and themorpholines the most toxic. Effects oftriazoles and strobilurines were variable, withreduction ranging from 37% to 100% fortriazoles and from 17% to 68% forstrobilurines.     

Carbohydrate and lipid components of hyphae and conidia of human pathogenFonsecaea pedrosoi

The carbohydrate and lipid components of mycelium and conidia ofFonsecaea pedrosoi (Brumpt) were analysed by paper, thin-layer and gas-chromatography, mass spectrometry and ultraviolet spectroscopy. Glucose, mannose, galactofuranose, rhamnose and glucosamine were polysaccharide components identified inF. pedrosoi. Significant changes in the carbohydrate pattern occurred during the conversion of mycelium into conidia. Rhamnose was predominant in conidia whereas galactose was prominent in mycelium. Palmitic, stearic, oleic, linoleic, and arachidonic acids were the fatty acids identified in the total lipid fraction. Palmitic and oleic acids were major fatty acids. Marked alterations in the fatty acid constituents were observed between the cell types ofF. pedrosoi. Arachidonic acid was detected only in conidia and linoleic acid was preferentially identified in mycelium. Differences in the sterol composition was also associated with morphogenesis inF. pedrosoi. Two main sterols, ergosterol and another less polar sterol, not fully characterized, were found in mycelium whereas in conidia only the latter sterol was present.     

l-Glutamic Acid Fermentation

It is well known that biotin has a marked effect on l-glutamic acid fermentation.

The authors have intended to find strains which are independent of the amounts of biotin in the culture medium. As a result, oleic acid-requiring mutants were obtained from a strain of Brevibacterium thiogenitalis which is an auxotroph for biotin. The growth of the mutant was remarkably stimulated by Tween 20, 40, 60, Ca ions and a small amount of corn steep liquor. And also, the mutant was found to have lost its requirement for biotin and showed growth response only to oleic acid or unsaturated fatty acids.

The effect of biotin, oleic acid and other unsaturated fatty acids on the production of l-glutamic acid was investigated by using an oleic acid-requiring mutant of Brevibacterium thiogenitalis No. 653. The results described in the present paper showed that the oleic acid-requiring mutant D-248 produced a large amount of l-glutamic acid in the excess biotin-contaming media, and that oleic acid seemed to be completely replaced by other unsaturated fatty acids such as palmitoleic acid and linoleic acid.     

影响飞虱虫疠霉孢子萌发类型和侵染性芽管形成的生化因子

孢子萌发类型是决定飞虱虫疠霉能否入侵的重要因子之一 ,而不同营养基质及昆虫体壁理化特性直接影响到孢子的萌发类型。对氨基酸、脂类、糖类、矿物质、维生素及桃蚜(Myzuspersicae)和褐稻虱 (Nilaparvatalugen)粗提物研究发现 ,它们均在不同程度上对芽管形成有刺激作用。其中 ,L 半胱氨酸、L 天冬酰氨、山俞酸 (C2 2 :0 )、海藻糖、果糖、麦芽糖、甘油、抗坏血酸、叶酸、维生素B1、ZnSO4、FeSO4以及两种寄主粗提物对芽管形成刺激作用显著。而这些基质如L 半胱氨酸、抗坏血酸、叶酸、维生素B1、FeSO4、ZnSO4及豆蔻酸 (C1 4 :0 )、软脂酸 (C1 6 :0 )、硬脂酸 (C1 0 :0 )、花生酸 (C2 0 :0 )、山俞酸 (C2 2 :0 )、掬焦油酸 (C2 4 :0 )、核黄素、烟酸能显著抑制二级分生孢子的产生。相反对刺激芽管形成不明显的物质如丙氨酸、酪氨酸、葡萄糖、半胞糖、蔗糖、肌醇、糖原、维生素B6、NaCl和KCl等能显著促进二级分生孢子的形成。此外 ,有些物质在高浓度下刺激芽管形成 ,而在低浓度下能促进二级分生孢子的形成 ,如L 天冬酰氨、海藻糖、…     

弯孢虫疫霉的分离和鉴定

1984—1987年,在福建的南平、福州、南安等地持续发生了由弯孢虫疫霉(Eryniacurvlspora)感染而引起库蚊(culex sp.)成虫死亡的流行病,病原菌分生孢子梗掌状分枝;分生孢子浅绿色,窄而长,略弯曲,单核,双囊壁,含有多个小脂肪粒,大小29.7—39.6×13.2—19.8(平均32.5×16.1)μm,长宽比1.5—3.0(平均2.0);次生分生孢子梨形,基部为钝的乳突,中间有一大的脂肪粒,孢子大小16.6—19.9×11.6—14.9(平均18.7×13.7)μm;休眠孢子球形,棕褐色,直径23.2—33.2(平均29.5)μm;有假根及囊状体。     

Fatty acid compositions of seed oils of Haematostaphis barteri and Ximenia americana

The fatty acid compositions of the seed oils of Haematostaphis barteri (blood plum) and Ximenia americana (Wild olive) plants were determined by the Gas Chromatography Mass Spectroscopy (GC-MS) technique. H. barteri contained six fatty acids with oleic (69.35%) and stearic (15.40%) the most abundant unsaturated and saturated fatty acids, respectively. Unsaturated higher fatty acids, namely Eicosadienoic (6.92%) and Erucic acid (2.74%) were detected and the total unsaturation for the oil was 79.01%. For X. americana, 10 fatty acids were identified of which seven were unsaturated yielding a total unsaturation of 92.42%. The oil contained essential fatty acids that is, Linoleic (1.34%), Linolenic (10.31%), Arachidonic (0.60%) and varying levels of unsaturated higher fatty acids, namely, Eicosatrienoic (3.39%), Erucic (3.46%) and Nervonic (1.23%) acids. The level of Oleic acid (72.09%) in the oil was close to the value for H. barteri.     

Does an increase in membrane unsaturated fatty acids account for Tween 80 stimulation of glucosyltransferase secretion by Streptococcus salivarius?

When Streptococcus salivarius was grown in batch culture in the presence of various Tween detergents, the fatty acid moiety of the detergent was incorporated into the lipids of its membrane. Tween 80 (containing primarily oleic acid) markedly stimulated the production of extracellular glucosyltransferase and also increased the degree of unsaturation of the membrane lipid fatty acids. The possibility that an increase in membrane unsaturated fatty acids promoted extracellular glucosyltransferase production was examined by growing cells at different temperatures in the presence or absence of Tween 80. The membrane lipids of cells grown at 30 degrees C, 37 degrees C and 40 degrees C without Tween 80 exhibited unsaturated/saturated fatty acid ratios of 2.06, 1.01 and 0.87 respectively. A significant increase in the production of extracellular glucosyltransferase was observed at 30 degrees C compared to cells grown at 40 degrees C. However, cells produced much more exoenzyme at all temperatures when grown with Tween 80. The results indicated that an increase in the unsaturated fatty acid content of the membrane lipids was not by itself sufficient to account for the stimulation of extracellular glucosyltransferase production by Tween 80, but that the surfactant also had to be present.     

Effect of various nonionic surfactants on growth of Escherichia coli

Rose, Michael J., Jr. (Veterans Administration Hospital, Washington, D.C.), Stephen A. Aron, and Bernard W. Janicki. Effect of various nonionic surfactants on growth of Escherichia coli. J. Bacteriol. 91:1863-1868. 1966.-Escherichia coli cultivated in media containing 0.5, 1.0, 2.0, or 4.0% concentrations of surface-active polyoxyethylene derivatives of formaldehyde polymers of octyl phenol (Triton WR-1339; Macrocyclon) or of sorbitan mono-fatty acid esters (Tween 20, 40, 60, and 80) exhibited significantly retarded growth only at the highest concentration. To determine the mechanism of bacteriostasis, certain derivatives and compounds related to the surfactants were investigated. Experiments with compounds related to the Triton-type agents demonstrated that incorporation of monomeric substances (Triton X-205, X-305, Igepal CA-730, or Dowfax 9N20) into the medium at a concentration of 4.0% did not inhibit the growth of E. coli. It was concluded that the formaldehyde polymer was essential for growth inhibition by the polyoxyethylene derivatives of octyl phenol. The inhibitory activity of the Tween compounds, in contrast, appeared to result from the unesterified fatty acids which contaminate the commercial preparations. Polyol (60), the sorbitan polyoxyethylene derivative of Tween 60 and the basic structural unit of all the Tween-type compounds, and a Tween 80 preparation which was purified by extraction of the unesterified oleic acid, were not inhibitory. Moreover, the amount of free oleic acid present as a contaminant of Tween 80 was found to be sufficient to cause significant growth inhibition. These results and the observation that E. coli does not appear to hydrolyze the esterified fatty acid of Tween 80 led to the conclusion that growth inhibition obtained with various Tween compounds probaby is a function of their respective fatty acid contaminants.