茶黄蓟马的生物学特性与防治

茶黄蓟马(Scirtothrips dorsalis)Hood是华南茶树上的重要害虫。一年可发生10—11代。5—10月份,11—21天便可完成一代,虫口高峰出现在9—10月,无明显越冬,成虫寿命7—25天,若虫期1—2龄4—10天,预蛹和蛹期2—6天;每雌产卵量平均35—62粒。成虫活跃,无趋光性,对黄色板和绿色板有正趋性。大叶种茶树虫口数量较多。少雨、干燥有利此虫发生。及时分批采摘和用高效灭百可或速灭杀丁6000倍液、喹硫磷1000倍液、水胺硫磷1500倍液对防治本虫有较好效果。     

甘蓝型油菜phytocyanin家族全基因组鉴定和表达分析

质体蓝素（phytocyanin,PC）是一类含铜电子转移蛋白,参与植物光合作用、生长发育以及对环境的适应等。为研究异源四倍体作物甘蓝型油菜的PC基因功能,对BnPC家族进行全基因组鉴定,共鉴定到173个成员。根据铜结合位点以及糖基化位点的差异将该基因家族的蛋白划分为4个亚家族：类早期结瘤素蛋白（BnENODL）、类花青苷蛋白（BnUCL）、类漆树蓝蛋白（BnSCL）和类质体蓝素蛋白（BnPLCL）。蛋白质序列特征分析结果表明,133个BnPC含有N端信号肽,77个BnPC具有糖基磷脂酰肌醇锚定信号,87个BnPC具有阿拉伯半乳聚糖结构域,104个BnPC具有N-糖基化位点。共线性分析结果表明,基因组复制和片段重复在该家族的扩张中起着重要作用。表达谱分析结果表明,部分BnPC基因的表达具有组织/器官特异性,95个BnPC基因至少对旱、盐、冷和高温胁迫中的一种产生响应。     

基于同源克隆技术分离玉米漆酶基因片段

漆酶是木质素生物合成途径的关键酶,其高度保守的铜离子结合区以及N末端糖基化位点使利用同源克隆技术成为可能。本研究利用GeneBank中公布的黑麦草漆酶基因全长cDNA序列及在玉米数据库中的比对结果设计特异引物,以8份AS系列玉米自交系为模板进行PCR筛选。经过提取质粒、测序及对推导的氨基酸序列进行比对,发现所克隆基因片段中含有保守的H-A-H基元和N末端糖基化位点,为以后玉米漆酶基因全长的克隆以及饲用玉米改良打下了基础。     

Artificial Diets With Different Protein Levels for Rearing Spodoptera frugiperda (Lepidoptera: Noctuidae)

Spodoptera frugiperda (J.E. Smith, 1797) (Lepidoptera: Noctuidae) is a pest of great economic importance which can feed on more than 300 plant species. As it is polyphagous, its host plants may have variable physical and chemical constitutions. This may influence larval development, as protein and carbohydrate levels are important factors for adequate biological development. The aim of this study was to evaluate insect developmental parameters as well as to compare the food consumption of S. frugiperda larvae reared using diets with different protein levels under laboratory conditions. Three artificial diet formulations were used: one typically used for routine laboratory rearing, based on bean, wheat germ and brewer’s yeast (D₁); one containing half the original amount of protein (D₂), and the other with twice the original amount of protein (D₃). The relative consumption rate (RCR), relative growth rate (RGR), and efficiency of conversion of ingested food (ECI) for S. frugiperda fourth instar larvae varied among diets. The protein present in the diet influenced the duration of larval and pupal periods and pupal weight, but did not affect larval survival, fecundity and longevity of adults. The different protein levels in the diets did not negatively influence population growth, so these three diet variations can be used for mass rearing in the laboratory. However, the influence of these diets on successive generations of the insect remains untested.     

Temperature-dependent development of Ascotis selenaria (Lepidoptera: Geometridae) and its stage emergence models with field validation

Temperature-dependent development of Ascotis selenaria (Denis et Schiffermüller) was studied in the laboratory. Time to egg eclosion decreased with increasing temperature and ranged from 17.4 d at 16 °C to 5.0 d at 30 and 32 °C. Total development times of larvae decreased from 54.7 d at 16 °C to 17.3 d at 32 °C. The development time of pupae ranged from 29.7 days at 16 °C to 10.2 days at 30 and 32 °C. Eggs, larvae and pupae did not develop successfully to the next stage at 12 and 35 °C. The estimated lower temperature thresholds were 10.4, 9.3, and 9.8 °C for eggs, larvae, and pupae, respectively. Thermal constants of egg, larvae, and pupae were 88.5, 370.4, and 188.7 DD, respectively. Stage emergence models for eggs, larvae, and pupae of A. selenaria were constructed by using the development rate model (Lactin 2 function) and development distribution model (three-parameter Weibull function), which simulate the proportion of individuals shifted from one stage to the next. Pearson's correlation coefficients between actual observations in the field and model outputs were statistically significant with 0.99, 0.68 to 0.87 and 0.96 to 0.98 for egg, larval and pupal stage emergence model, respectively. The egg stage emergence model could be used to facilitate spraying time as it successfully predicted the first instar larval population. Predictability of the pupal stage emergence model was greatly improved when the physiological age of overwintering pupae was assumed to be in various state. The stage emergence models developed here should be useful to construct an A. selenaria population model.     

Transgenic Bt corn varietal resistance against the Mexican rice borer,Eoreuma loftini (Dyar) (Lepidoptera: Crambidae) and implications to sugarcane

The Mexican rice borer, Eoreuma loftini (Dyar), attacks crops including corn, Zea mays L., rice, Oryza sativa L., sorghum, Sorghum bicolor (L.) Moench, and sugarcane, Saccharum spp. Strongly resistant varieties of any kind, native or otherwise, have not been identified. A field plot corn variety test using two transgenic Bt varieties, Pioneer 31G71, expressing the Cry1F insecticidal protein, and Golden Acres 28V81, expressing the Cry1A.105, Cry2Ab2, and Cry3Bb1 insecticidal proteins, and two non-Bt controls, Dekalb DKC 69-72 and BH Genetics 9050, all four commonly grown in the Lower Rio Grande Valley of Texas, showed that, although oviposition preference was not affected, 28V81 resisted larval stalk boring to the extent that Mexican rice borer injury was almost non-existent. Pioneer 31G71 was infested nearly as much as the controls, but larval development to adulthood was reduced by ≈70%. Rearing larvae on 5, 50, 500, and 5000 μg of corn leaf tissue per ml of artificial diet showed that, while the three lowest concentrations did not affect larval growth and development, the high concentration of 28V81 reduced survivorship to the pupal stage, decreased weight of 4-wk-old larvae, and prolonged development to pupation. Lower numbers of pheromone trap-captured adults at the edges of commercial Bt and non-Bt corn fields showed that populations were lower at the Bt cornfields, suggesting a lesser rate of adult production. Because corn is a preferred host plant over sugarcane, sorghum or rice, use of resistant transgenic Bt corn varieties will likely protect the crop from the substantial injury that can be caused by the pest. This study also suggests that Bt genes might result in similarly strong resistance when inserted in other vulnerable crops such as sugarcane.     

Acute toxicity and sublethal effects of methoxyfenozide and thiodicarb on survival,development and reproduction of Helicoverpa armigera (Lepidoptera: Noctuidae)

The cotton bollworm Helicoverpa armigera (Hubner) is one of the most destructive pest insects in Iran and many other countries. In this study, lethal and sublethal effects of methoxyfenozide, and thiodicarb were evaluated against H. armigera larvae that fed on insecticide-treated artificial diet. The effects of methoxyfenozide and thiodicarb were assessed in 3rd instars. Methoxyfenozide and thiodicarb showed LC₅₀ values of 4 and 639 mg a.i./ml, respectively, in H. armigera larvae. Sublethal effects on development, adult longevity, and reproduction were observed in H. armigera larvae that survived exposure to an LC₃₀ of the insecticides. Larvae that were exposed to an LC₃₀ concentration of methoxyfenozide exhibited lower pupal weight and increased larval and pupal developmental times compared with thiodicarb treated larvae or control larvae. Adults that were exposed as larvae to an LC₃₀ concentration of methoxyfenozide or thiodicarb showed reduced fecundity (35% and 30%, respectively) compared to control adults. The tested insecticides significantly reduced adult longevity. The longevity of adult females that as larvae were treated with an LC₃₀ concentration of methoxyfenozide or thiodicarb was reduced by 28% and 23%, respectively, in comparison to control females. We predict that the combination of lethal and sublethal effects of the insecticides, especially methoxyfenozide, will induce significant effects on field population dynamics of H. armigera.     

养分胁迫对水稻籽粒灌浆充实影响的蛋白质组学研究

 以杂交早稻威优916为试验材料,采用水培方式栽培,生育后期设置养分胁迫和全营养液两种处理,从蛋白质组学角度研究后期持续的养分胁迫对水稻籽粒灌浆的影响,以期为水稻高产栽培提供科学依据。籽粒蛋白质经双向电泳分离后共获得了37个发生差异表达的蛋白质,经串联质谱分析(ESI Q MS/MS),27个蛋白质功能得到鉴定,包括4个参与光合作用的蛋白质、13个与籽粒充实发育相关的蛋白质、9个逆境相关的蛋白质及1个呼吸代谢相关的蛋白质。分析结果表明,养分胁迫下,逆境相关蛋白质在籽粒灌浆的前中期大量上调表达,籽粒光合作用减弱,后期呼吸作用增强,籽粒的氮代谢受到显著影响,谷蛋白及胚蛋白表达相对滞后,蛋白质和脂肪合成减少,从而造成籽粒灌浆不足,产量降低。     

Prevalence of Helicoverpa zea (Lepidoptera: Noctuidae) on late season volunteer corn in Mississippi: Implications on Bt resistance management

The southern United States has a long growing period between corn, Zea mays L., harvest and first winter frost, so volunteer corn which germinates after harvest has a growing period sufficient for corn earworm, Helicoverpa zea (Boddie) and fall armyworm, Spodoptera frugiperda (J. E. Smith) to feed on these plants. However, lower air temperatures can limit larval development on late season volunteer corn and thereby successful pupation. Here we explore the suitability of late season volunteer corn for larval development and the potential contribution of H. zea larvae to the overwintering population. Our survey revealed the occurrence of volunteer corn in high densities, with monthly mean densities ranging from 56,000 to 143,000 plants ha⁻¹. H. zea larvae were found feeding on both vegetative and reproductive stage plants while S. frugiperda were only found on vegetative stage plants. An analysis of H. zea growing degree day (GDD) accumulations based on Mississippi weather data from 1980 to 2010 revealed that sufficient GDD to reach prepupation would always be accumulated before first frost if oviposition occurred by 9 September, with the probability of successful pupation decreasing rapidly thereafter. However, most of the H. zea larvae were oviposited after this, and could not reach pupation. Because S. frugiperda cannot overwinter in Mississippi, their ability to pupate was not examined. Low suitability of whorl stage corn for H. zea development coupled with low larval densities during this stage effectively diminish the number of larvae that complete development on late season volunteer transgenic corn expressing genes from the soil bacterium, Bacillus thuringiensis (Bt). This limits the Bt resistance risk posed by larvae developing on late season volunteer corn in all but the most southern locations in the US.     

野生一粒小麦根干旱响应蛋白的筛选与鉴定

为解析野生一粒小麦根响应干旱胁迫的调控网络,用20%(w/v)PEG6000处理两叶一心期野生一粒小麦,通过对小麦根蛋白质的分离和鉴定,分析了干旱胁迫下野生一粒小麦根中的蛋白质变化。结果共分离、鉴定得到85个表达差异倍数在1.5以上的蛋白质。这些差异蛋白主要涉及碳代谢(27%)、氨基酸代谢(15%)、解毒与防御(11%)、分子伴侣(8%)、能量代谢(8%)、信号传导(6%)、蛋白质代谢(5%)、脂代谢(4%)、转录与翻译(4%)、核苷酸代谢(2%)以及骨架蛋白(1%)。对这些表达差异蛋白进行进一步的功能分析,发现大部分信号传导相关蛋白上调表达;碳代谢途径中的糖酵解相关蛋白下调表达,而磷酸戊糖途径相关蛋白上调表达。同时下调表达的还包括蛋白质代谢相关蛋白。大部分氨基酸代谢相关蛋白质下调表达,但是谷氨酸脱羧酶及甲硫氨酸合酶含量上升。结果表明,干旱胁迫增强了野生一粒小麦根中信号传导与磷酸戊糖途径代谢,促进了谷氨酸与甲硫氨酸的生物合成,降低了糖酵解与蛋白质代谢等过程。研究结果丰富了野生一粒小麦根响应干旱胁迫机制信息。     

Efficacy of entomopathogenic nematodes (Nemata: Rhabditida) to control Brazilian apple leafroller Bonagota salubricola (Meyrick, 1937) (Lepidoptera: Tortricidae)

The Brazilian apple leafroller, Bonagota salubricola (Meyrick, 1937) (Bonagota cranaodes) (Lepidoptera: Tortricidae), is one of the main pest problems in apple orchards is Brazil. The purpose of this work was to evaluate B. salubricola larval and pupal susceptibility to different species of entomopathogenic nematodes, isolated in Rio Grande do Sul state in Brazil, under laboratory and field (apple orchard) conditions. Bioassays for isolates selection and determination of lethal concentration were performed in tubes of 1.5 ml (eppendorf), each containing one B. salubricola third instar larvae and filter paper. Field experiments were performed in commercial orchard, with application of 100 infecting juveniles (IJs)/cm² for each apple plant previously infected with five B. salubricola larvae covered with plastic trays containing thin cloth. Nematodes H. bacteriophora RS107 and H. bacteriophora RS57 had LC₅₀ of 13 and 4.5 IJs/larvae (4.3 and 1.5 IJs/cm²), respectively. In the field, H. bacteriophora RS107 and H. bacteriophora RS57, applied with sorbitol as an adjuvant, reached 70.2 and 61.1% larval mortality, respectively. The results showed that both isolates had biological activity against B. salubricola under laboratory and field conditions.     

Evidence of genetic transmission of antibiosis and antixenosis resistance of sorghum to the spotted stemborer, Chilo partellus (Lepidoptera: Pyralidae)

Spotted stemborer, Chilo partellus (Swinhoe) (Lepidoptera: Pyralidae), is the most important pest of sorghum in Asia and south and eastern Africa. Host plant resistance is an important control tactic for controlling this pest. Two breeding lines 27B × PB 15881-3 and 463B × PB 15881-3 with their parents, resistant and susceptible genotypes were evaluated in the field, glasshouse and laboratory for different resistance parameters. Breeding lines and genotypes varied significantly in foliar damage ratings, percentage of stem length tunneled, percentage of plants with deadhearts, larval survival, larval and pupal weights, larval and pupal duration, and percentage pupation and adult emergence in diets amended with leaf powder of different sorghum genotypes. The breeding lines 27B × PB 15881-3 and 463B × PB 15881-3 showed antixenosis and antibiosis to C. partellus in terms of reduced eggs per plant, larval survival and development. The levels of antixenosis and antibiosis of both breeding lines were similar to their resistant parents. Results indicate that transmission of characteristics responsible for resistance to the progeny from the resistant parent occurred.     

Sublethal and transgenerational effects of chlorantraniliprole on biological traits of the diamondback moth,Plutella xylostella L.

The diamondback moth, Plutella xylostella (L.), is an important international pest of cruciferous vegetables. The effects of the new diamide insecticide chlorantraniliprole, at a lethal concentration inducing only 25% mortality (LC₂₅), were assessed on the development and reproductive parameters of P. xylostella under laboratory conditions. In addition, effects on development time, pupation rate, larval and pupae weight, fertility, and survival in the parent and F1 generations were assessed. When 4th instar P. xylostella larvae were exposed to LC₂₅ of chlorantraniliprole on a cabbage (Brassica oleracea var. capitata L.) leaf for 96 h, we observed increased developmental time for 4th instar larval to pupa period (4.27 days vs. 3.34 days in the control), lower pupal weight (3.58 mg vs. 4.17 mg in the control) and decreased adult fecundity (by 42%). F1 generation underwent transgenerational effects, i.e. higher developmental time from egg to pre-pupae and lower egg hatching rate occurred. Demographic growth parameters, such as the net reproductive rate (R₀), the intrinsic rate of increase (r_m), and finite rate of increase (λ) were significantly lower for the LC₂₅ chlorantraniliprole treated group than for the untreated control. Our results suggest that exposure to LC₂₅ of chlorantraniliprole may have negative effects both on exposed individuals and on subsequent generations in P. xylostella.     

孕穗期水稻不同功能叶的发育蛋白质组学分析

 从蛋白质组学角度对杂交水稻汕优63孕穗期4个叶位功能叶片蛋白质组变化进行了研究,以揭示水稻孕穗期叶片蛋白质组的表达差异。4个不同时期功能叶片蛋白质经双向电泳得到分离,应用Imagemaster 2D Elite 5.0软件对所得到的双向电泳图谱进行分析比较,共得到差异表达蛋白质点23个,差异表达蛋白质点经质谱分析,有14个得到鉴定。对鉴定出的蛋白功能进行研究,结果表明:差异表达的蛋白质大部分(9个)为参与光合作用和呼吸作用的蛋白质;其次为与蛋白结构及功能调控相关的蛋白质(3个),表达量表现为随叶位上升而上调;其余为参与氨基酸代谢的蛋白质(2个),表达量在较低叶位叶片中无显著规律,在剑叶中的表达量显著上调。蛋白质是细胞功能执行者,受细胞功能或细胞环境变化的影响,因此,上述蛋白质发生变化的原因应与水稻不同叶位叶片生长发育特性有关。     

Lethal and sublethal effects of imidacloprid and buprofezin on the sweetpotato whitefly parasitoid Eretmocerus mundus (Hymenoptera: Aphelinidae)

The parasitoid Eretmocerus mundus Mercet (Hymenoptera: Aphelinidae) is one of the key natural enemies of Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae). Lethal and sublethal effects of imidacloprid and buprofezin on emergence and key biological and population parameters of E. mundus exposed during different developmental stages were studied. Dose–response bioassays were carried out on adult wasps using a leaf dipping method. The emergence rates of adults were reduced significantly by the field-recommended concentrations of the insecticides. However, the emergence rates were not affected either by the stage of the parasitoid at the time of exposure (larval and pupal stages), and there was no interaction between treatments and time of exposure. No significant mortality of E. mundus adults was observed following buprofezin treatment. The LC₅₀ of imidacloprid on adults was 4.75 ppm. The results showed that the longevity and fecundity of E. mundus adults were reduced significantly by the two insecticides, though the sex ratio of E. mundus offspring was not affected. Population parameters of the parasitoid such as R₀, r_m and T were also significantly reduced by the insecticides. Our results indicated that, in addition to lethal effects, sublethal effects should also be considered when these insecticides are applied in IPM programs for this pest.     

淹水胁迫下不同活力玉米种子定量蛋白质组研究

以高活力玉米自交系J002和低活力玉米自交系196为试验材料,采用TMT标记定量蛋白质组学技术,对不同活力玉米种子萌发期进行淹水胁迫72 h处理,比较蛋白质表达的差异。结果表明,共鉴定到203个差异蛋白,其中,上调蛋白169条,下调蛋白34条。通过对差异表达蛋白的功能富集分析和KEGG代谢通路富集分析发现,高活力种子在萌发过程中核糖体蛋白的合成量要高于低活力种子。在缺氧胁迫下,高活力种子的ROS清除剂如POD、SOD、APX等丰度均高于低活力种子。KEGG通路分析表明,高活力种子激活了糖酵解代谢、丙酮酸代谢等更多的代谢途径来获得能量。鉴定出一些丰度具有巨大差异的热激蛋白HSPs,由此可以推断,高活力种子具有更好抗性的分子机制。     

Interaction between host plant resistance and biological activity of Bacillus thuringiensis in managing the pod borer Helicoverpa armigera in chickpea

The legume pod borer Helicoverpa armigera (Hubner) (Lepidoptera: Noctuidae) has developed high levels of resistance to conventional insecticides, and therefore, efforts are being made to develop transgenic chickpea expressing toxin genes from the bacterium Bacillus thuringiensis (Bt) for controlling this pest. However, there is an apprehension that acid exudates in chickpea might interfere with the biological activity of Bt. Therefore, we studied the biological activity of Bt (Biolep^R) on four chickpea genotypes with different levels of resistance to H. armigera under field conditions, and by incorporating lyophilized leaf and pod tissue into the artificial diet with and without Bt. The pH of the acid exudates varied from 2.1 to 2.9, and malic and oxalic acids were the major components of the acid exudates in different chickpea genotypes. There was no survival of H. armigera larvae in chickpea plants sprayed with 0.1, 0.2 and 0.5% Bt. There was a significant reduction in larval survival, larval and pupal weights and fecundity, and prolongation of larval and pupal periods in chickpea plots sprayed with Bt (0.05%) as compared to the unsprayed plots. Biological activity of Bt was lower on artificial diets with leaf or pod powder of chickpea genotypes, which might be because of a low intake of Bt toxins due to the antifeedant effects of acid exudates in the chickpea or reduction in biological activity of Bt due to the interaction of biochemical constituents in chickpea with the Bt toxins. Larval survival, larval and pupal weights, pupation and adult emergence were significantly lower on diets with leaf or pod powder of the H. armigera-resistant genotypes than on the susceptible check. Chickpea genotypes with resistance to H. armigera acted in concert with Bt to cause adverse effects on the survival and development of this insect. The results suggested that development of transgenic chickpeas expressing toxin genes form Bt will be quite effective for controlling of the pod borer, H. armigera.     

不同生育期芝麻根系分泌物对连作障碍的响应及其自毒作用

为探讨芝麻根系分泌物中可能导致连作障碍的化感物质,以江西主栽品种金黄麻为材料,设置正茬与连作处理,研究芝麻现蕾期、盛花期和成熟期根系分泌物的组分变化与差异。结果表明：正茬芝麻根系分泌物对芝麻种子的发芽表现出“低促高抑”现象。正茬和连作芝麻在现蕾期、盛花期和成熟期的根系分泌物中鉴定出18～28种有机物。现蕾和盛花期芝麻根系分泌物均含有酯类、烃类、酸类、酚类、胺类、醇类和酮类物质,以反式-（2,3-二苯基环丙基）-苯亚砜甲酯相对丰度为最高;成熟期比现蕾和盛花期多醚类物质,以辛乙烯二醇单正十二烷基酯相对丰度为最高。酯类物质是芝麻根系分泌物的重要组分,尤其在现蕾期其总相对丰度达到75.12%（正茬）、52.96%（连作）。其中,邻苯二酸二异辛酯和辛乙烯二醇单正十二烷基酯的相对丰度在连作芝麻根系分泌物比正茬中高9.48和5.73个百分点。酸类物质在芝麻成熟期根系分泌物中含量最高,总相对丰度在正茬与连作芝麻根系分泌物中分别达17.53和42.71个百分点。其中,连作芝麻根系分泌物中棕榈酸、亚油酸和硬脂酸的相对丰度依次提高15.78、1.33和1.15个百分点;油酸、肉豆蔻酸仅在连作芝麻根系分泌物中检测到,相对丰度为10.66和1.62个百分点。与正茬相比,芥酸酰胺在现蕾期和盛花期的连作芝麻根系分泌物中相对丰度分别提高21.68和11.51个百分点;油酸酰胺相应提高2.16和7.44个百分点。综上,连作改变了芝麻根系分泌物组分。     

Structural and Immunochemical Studies of the Lipopolysaccharide from the Fish Pathogen,Aeromonas bestiarum Strain K296, Serotype O18

Chemical analyses and mass spectrometry were used to study the structure of the lipopolysaccharide (LPS) isolated from Aeromonas bestiarum strain K296, serotype O18. ESI-MS revealed that the most abundant A. bestiarum LPS glycoforms have a hexa-acylated or tetra-acylated lipid A with conserved architecture of the backbone, consisting of a 1,4′-bisphosphorylated β-(1→6)-linked d-GlcN disaccharide with an AraN residue as a non-stoichiometric substituent and a core oligosaccharide composed of Kdo₁Hep₆Hex₁HexN₁P₁. 1D and 2D NMR spectroscopy revealed that the O-specific polysaccharide (OPS) of A. bestiarum K296 consists of a branched tetrasaccharide repeating unit containing two 6-deoxy-l-talose (6dTalp), one Manp and one GalpNAc residues; thus, it is similar to that of the OPS of A. hydrophila AH-3 (serotype O34) in both the sugar composition and the glycosylation pattern. Moreover, 3-substituted 6dTalp was 2-O-acetylated and additional O-acetyl groups were identified at O-2 and O-4 (or O-3) positions of the terminal 6dTalp. Western blots with polyclonal rabbit sera showed that serotypes O18 and O34 share some epitopes in the LPS. The very weak reaction of the anti-O34 serum with the O-deacylated LPS of A. bestiarum K296 might have been due to the different O-acetylation pattern of the terminal 6dTalp. The latter suggestion was further confirmed by NMR.