Dancing to the rhythms of geological time: the biorhythm capabilities of Polychaeta in a geological context

Summary

Errant polychaete worms in the Orders Eunicida (family Eunicidae) and Phyllodocida (families Nereidae and Polynoidae) exhibit a highly developed biorhythmic capability. The Pacific palolo worms are well known for a precisely timed annual breeding event in which mass spawning occurs at a particular time of day, on one day per year, that day having a fixed relationship to the lunar period. Nereidae and Polynoidae exhibit photoperiodic responses that determine the breeding season by regulation of oocyte growth. Nereis virens shows short-term cycles of foraging activity; automated recording of these patterns has revealed four distinct behaviour rhythm phenotypes: circadian, tidal, lunidian and arrhythmic, the last phenotype being expressed during the photoperiod induced growth diapause. The Eunicids and Phyllodocids are represented in the fossil record by scolecodonts, their fossilised jaws. There was a major radiation of these polychaetes during the Ordovician and the earliest suggested polychaete fossils are from the Cambrian. The simultaneous expression of tidal and circadian rhythmicity is characteristic of intertidal animals and it is likely that this complex behavioural repertoire was found in the ancestors of modern terrestrial forms, such as tetrapods and arthropods, prior to their emergence onto land during the Carboniferous and Silurian periods at least 400 Ma. The period of the earth's rotation, and hence day length and tidal period, has long been known to be increasing, and additionally the moon to be retreating from the earth, due to the phenomenon of tidal friction caused by the gravitational interactions between the moon and the earth. These changes are significant over a geological time scale. Consequently, the length of day was substantially less (and the number of days in a year more) than at present in the Cambrian and Ordovician periods. Recent theoretical analysis of the period of the earth's rotation suggests that the day length prior to a critical period (t _crit ) around 1800 Ma may have been stable, with a length of only 4 h. At that time a period of more rapid change in the dynamics of the rotation was initiated. The implications of this theory for the evolution of the biological clock are discussed.     

Gliocladium deliquescens NRRL 1086对偏诺皂苷元的生物转化研究(英文)

在前期研究基础上,本实验考察了Gliocladium deliquescens NRRL 1086对偏诺皂苷元皂苷元C-3位的微生物糖基化能力。利用IR、HR-ESI-MS、NMR等方法,确定G.deliquescens NRRL 1086可以将偏诺皂苷元转化为偏诺皂苷元3-O-β-D-吡喃葡萄糖苷。同时研究表明G.deliquescens NRRL 1086不能在另外5种甾体皂苷元C-3位上引入糖基取代。实验结果进一步验证了G.deliquescens NRRL 1086对甾体皂苷元的选择性糖基化能力。     

Effect of peat-bran inoculum ofTrichoderma species on biological control ofRhizoctonia solani in lettuce

A range of known biocontrol or plant growth-stimulating species ofTrichoderma orGliocladium were grown on peat-bran substrate to yield between 5×10⁷–3×10¹⁰ colony forming units (cfu's)g^–1 substrate after 14 days growth. Inocula were incorporated into peat:sand potting compost infested withRhizoctonia solani to give 7–8 × 10⁴ cfu's of antagonist g^–1 compost and assessed for biological control activity using lettuce seedlings. Six of the eight antagonists decreased daming-off and three of these consistently increased yield in comparison withR. solani treatment alone.Subsequently, peat-bran inoculum ofT. harzianum isolate TH1 was incorporated at 0.5% w/v intoR. solani infested potting compost. Both autoclaved and nonautoclaved inoculum ofT. harzianum TH1 decreased disease and increased yield. Incorporation of ethyl acetate-extracted autoclaved inoculum ofT. harzianum TH1 resulted in similar levels of biocontrol and improved plant growth as did incorporation of nonautoclaved and autoclavedT. harzianum TH1 inoculum. The need to standardize inocula and controls is emphasized.     

稻曲病菌厚垣孢子脂肪酸组成的研究

【目的】为探明细胞壁和细胞内脂肪酸成分及含量与细胞抗逆性的关系,【方法】采用酸热法、索氏提取法、有机溶剂法对稻曲病菌的厚垣孢子壁进行脂肪酸提取,并采用气相色谱检测其脂肪酸的组成和含量。【结果】采用酸热法提取脂肪酸效果最好,以该方法提取测定稻曲病菌黄色、黄绿色、黑色厚垣孢子壁饱和脂肪酸相对含量分别为26.92%、17.23%、23.71%,其不饱和脂肪酸相对含量分别为60.46%、61.52%、70.64%;厚垣孢子总(沉淀孢子壁和上清液)饱和脂肪酸相对含量分别为28.87%、21.00%、24.04%,厚垣孢子总不饱和脂肪酸相对含量分别为55.43%、55.87%、63.89%。硬脂酸在厚垣孢子壁中的含量:黄色>黄绿色>黑色;不饱和脂肪酸中顺式-5,8,11,14,17二十碳五烯酸(EPA)在厚垣孢子壁的含量:黑色>黄绿色>黄色。【结论】在3种颜色厚垣孢子中,黑色休眠型厚垣孢子在孢子壁、总不饱和脂肪酸含量均最高,表明不饱和脂肪酸的含量提高,有利于厚垣孢子的休眠越冬。     

稻曲病菌AFLP反应体系的建立及其初步应用

本研究通过一系列梯度试验建立了最佳的稻曲病菌AFLP(Amplifiedfragmentlengthpolymor-phism)反应体系,并从256对EcoRⅠ和MseⅠ引物组合中选择30对条带清晰、多态性好的引物组合分析了2003年北京昌平基地的40个稻曲病菌株的遗传多样性。     

福州大叶榕隐头果内榕小蜂的分类

通过对福州两个样地大叶榕雄花期隐头果进行定时、定点采集,观察与鉴定,从546个花序果内共收集到榕小蜂33641头,隶属于小蜂总科中的7个科(亚科)7个属的11个种,其中传粉小蜂为榕小蜂科的Platyscapa coronata,其余10种非传粉小蜂分别隶属于隐针榕小蜂亚科Epichrysomallinae,金小蜂科Pteromalidae的锥尾榕小蜂亚科Otitesellinae和延腹榕小蜂亚科Sycoryctinae,广肩小蜂科Eurytomidae,刻腹小蜂科Ormyridae和姬小蜂科Eulophidae。传粉小蜂和非传粉小蜂的种类和数量呈现明显的季节性。冬-春季(12-翌年5月)榕果内小蜂的种类和数量较多,传粉榕小蜂是优势种;夏-秋季(6-11月间)小蜂种类和数量略少,Camarothorax bismasculinus和Sycophila sp.1是优势种。在非传粉小蜂中,Camarothorax、Sycophila、Otitesella、Sycoscapter等4个属的榕小蜂为常见种,而Ormyrus和Aprostocetus等2个属的榕小蜂为偶见种。根据小蜂的形态特征制定大叶榕隐头果中榕小蜂种类检索表,本实验为榕小蜂分类、榕-蜂协同进化研究,以及非传粉小蜂对榕-蜂共生体系的影响等研究提供科学依据。     

Baiting with Sclerotium rolfsii for selective isolation of Gliocladium virens from natural soil

A baiting technique for selective isolation of Gliocladium virens from natural soil was developed by mixing Sclerotium rolfsii —colonized sorghum grains with moist natural soil and incubating at 30 ± 5°C for 6–10 days. G. virens developed large, distinct colonies on the soil surface by colonizing S. rolfsii and was then easily isolated for use in biocontrol programmes. Trichoderma spp. were present in the soil but never developed conspicuous colonies on the soil surface, even when the soil was supplemented with large numbers of conidia.     

Different mechanisms of Trichoderma virens‐mediated resistance in tomato against Fusarium wilt involve the jasmonic and salicylic acid pathways

In the present study, we investigated the role of Trichoderma virens (TriV_JSB100) spores or cell‐free culture filtrate in the regulation of growth and activation of the defence responses of tomato (Solanum lycopersicum) plants against Fusarium oxysporum f. sp. lycopersici by the development of a biocontrol–plant–pathogen interaction system. Two‐week‐old tomato seedlings primed with TriV_JSB100 spores cultured on barley grains (BGS) or with cell‐free culture filtrate (CF) were inoculated with Fusarium pathogen under glasshouse conditions; this resulted in significantly lower disease incidence in tomato Oogata‐Fukuju plants treated with BGS than in those treated with CF. To dissect the pathways associated with this response, jasmonic acid (JA) and salicylic acid (SA) signalling in BGS‐ and CF‐induced resistance was evaluated using JA‐ and SA‐impaired tomato lines. We observed that JA‐deficient mutant def1 plants were susceptible to Fusarium pathogen when they were treated with BGS. However, wild‐type (WT) BGS‐treated tomato plants showed a higher JA level and significantly lower disease incidence. SA‐deficient mutant NahG plants treated with CF were also found to be susceptible to Fusarium pathogen and displayed low SA levels, whereas WT CF‐treated tomato plants exhibited moderately lower disease levels and substantially higher SA levels. Expression of the JA‐responsive defensin gene PDF1 was induced in WT tomato plants treated with BGS, whereas the SA‐inducible pathogenesis‐related protein 1 acidic (PR1a) gene was up‐regulated in WT tomato plants treated with CF. These results suggest that TriV_JSB100 BGS and CF differentially induce JA and SA signalling cascades for the elicitation of Fusarium oxysporum resistance in tomato.     

链孢粘帚霉几丁质酶的诱导及其抗真菌活性研究

链孢粘帚霉HL-1-1菌株在不同培养条件下产几丁质酶活性不同,核盘菌菌核对其几丁质酶的诱导作用高于几丁质;首次用菌核配制培养基成功诱导了几丁质酶的产生,其产酶的最适初始pH值为4.5,最适培养时间为6d。几丁质酶对10种病原菌都有不同的抑制作用,对小麦雪腐病、葡萄白腐病、玉米黄斑病及斑点落叶病等病原菌的孢子萌发具有明显的抑制作用;该几丁质酶还能明显抑制核盘菌和立枯丝核菌的菌核萌发。     

Biocontrol of Sclerotinia sclerotiorum infection of cabbage by Coniothyrium minitans and Trichoderma spp.

Nine fungal isolates [Clonostachys rosea (1), Coniothyrium minitans (1), Trichoderma crassum (1), T. hamatum (4), T. rossicum (1) and T. virens (1)] were tested in two bioassays for their ability to degrade sclerotia and reduce apothecial production and carpogenic infection of cabbage seedlings. C. minitans LU112 reduced apothecial production in both bioassays, with T. virens LU556 significantly reducing apothecial production in the sclerotial parasitism assay. Both isolates also reduced sclerotial viability in this assay to 5% for C. minitans and 22% for T. virens. C. minitans LU112 and T. virens LU556 reduced the infection of cabbage seedlings in the pot bioassay 126 days after sowing but not after 147 days, partly due to ascospore cross-infection between treatments. C. minitans LU112, T. virens LU556 and T. hamatum LU593 as maizemeal-perlite (MP) soil incorporation and transplant potting mix incorporation were evaluated for their ability to control Sclerotinia sclerotiorum disease of cabbage in field experiments. S. sclerotiorum infection of cabbage was reduced by 46–52% and 31–57% by both C. minitans LU112 and T. hamatum LU593 as MP soil incorporations, respectively, in the two field experiments. T. virens LU556 MP soil incorporation and C. minitans LU112 and T. hamatum LU593 transplant potting mix incorporations reduced S. sclerotiorum disease in the first experiment but not in the second experiment. A commercial C. minitans LU112 formulation, C. Mins LU112 WG, also significantly reduced S. sclerotiorum disease by 59%. Soil incorporation of C. minitans and T. hamatum was shown to have potential to control S. sclerotiorum disease in cabbage.