Yeast-like symbiotes as a sterol source in anobiid beetles (Coleoptera,Anobiidae): possible metabolic pathways from fungal sterols to 7-dehydrocholesterol

Insects are unable to synthesize sterols and require exogenous sterol sources for their normal development and reproduction. A few exceptions are insects associated with symbiotic yeasts or fungi. We analyzed sterols by GC-MS in two anobiid beetles (Lasioderma serricorne and Stegobium paniceum), their intracellular yeast-like symbiotes (YLS), and their diets in order to clarify the sterols synthesized by YLS and the metabolic pathways of the sterols in the beetles. Several C(27), C2(8), and C(29) saturated and unsaturated sterols were identified; the predominant sterols were cholesterol and 7-dehydrocholesterol in the anobiid beetles and ergosterol in the YLS. Most sterols detected in YLS were those known in the late pathway of the ergosterol biosynthesis in yeasts and most of the sterols in the beetles appear to be intermediate metabolites from YLS sterols to 7-dehydrocholesterol. The anobiid beetles appear to use ergosterol and 5-dihydroergosterol as sources for 7-dehydrocholesterol.     

Responses of stored-product Anobiidae to pheromone lures and plant-derived volatiles

Experiments were conducted in different locations to investigate responses of adult Stegobium paniceum and Lasioderma serricorne (Col., Anobiidae) to different commercially available or prototype fabrications of their female‐produced sex pheromones. The results showed that the number of S. paniceum captured in traps baited with the commercially available lures was significantly higher than those captured in traps baited with the prototype stegobinone lures. The three commercially available brands of serricornin lures investigated were equally effective in capturing L. serricorne. In a related study, we conducted a 9‐week trapping experiment to determine if responses of L. serricorne to serricornin can be enhanced by the presence of host plant odours. Traps were baited with serricornin alone, serricornin plus dried red chilli (Capsicum frutescens L.) or red chilli alone. The results showed that the number of beetles captured in traps baited with a combination of serricornin and chilli volatiles were significantly higher than in traps baited with pheromone or chilli volatiles alone, indicating that potential exist for improved monitoring or mass trapping of L. serricorne by combining pheromone with plant‐derived volatiles present in Capsicum spp.     

药材甲发育起点温度和有效积温

在恒温条件下用新鲜药材甘遂饲养药材甲Stegobium paniceum(L.),测定药材甲各虫态(龄)的发育历期,结果表明,该虫卵、幼虫、蛹、产卵前期及世代发育起点温度分别是5.05,8.45,9.06,8.36和8.01℃,有效积温分别是177.9,745.5,127.9,37.8和1094.1日.度。     

金发草LEA 3 基因两个剪接体转化酿酒酵母的抗非生物胁迫功能分析

对金发草(Pogonatherum paniceum)第3组LEA蛋白(PpLEA3)基因两个剪接体进行分析,并利用酿酒酵母表达系统分析两个剪接体在不同非生物胁迫的响应差异.以PpLEA3基因两个剪接体(PpLEA3.a和PpLEA3.b)的重组载体pMD19-T-PpLEA3.a和pMD19-T-PpLEA3.b为模板,PCR法构建酵母表达载体pYES2-PpLEA3.a和pYES2-PpLEA3.b,并转化酿酒酵母细胞得到重组菌INV-PpLEA3.a和INV-PpLEA3.b.通过比较重组菌和对照菌(转空载体pYES2)在NaCl、NaHCO3、低温、干旱、UV胁迫下的恢复生长状况,结果表明两种重组菌胁迫后的生长情况明显好于对照菌,两个剪接体对非生物胁迫抵抗力的大小为:PpLEA3.a＞PpLEA3.b.两个剪接体在核酸序列上的差异导致了在蛋白亲水性和结构上的差异,最终导致了在抗逆能力方面的差异.     

岩生植物金发草生长特征研究

研究了重庆地区金发草在3种基质种生境中的生长特征.结果表明,种生境下金发草基径、冠幅、高度及根系面积、最长根和根深差异极显著.3种基质中,紫色土中金发草的地上部分基径(15.18cm)、冠幅(3086.77cm²)和高度(66.8cm)均为最大值,而紫色砂岩金发草的基径(10.89cm)、冠幅(1868.79cm²)和高度(60.7cm)均为最小值,但差异不显著.砂岩中金发草的根系比紫色土中分布广泛,差异显著,说明岩石生境中金发草将较多生物量投入到根系,通过增加根系的生长,提高其在岩石上的固着能力,扩大根系吸收面积,忍耐岩石基质的干燥和贫瘠.     

金发草枝构件格局及其环境变异

研究分析了岩生植物金发草的枝构件特征,结果表明:金发草的分枝角度一般在 30°以内,节间距小于6 cm,平均每节有1个分枝,分枝率约为3;随植物生长级别加大,金发草枝构件空间分形维数逐步从1.282递增到1.664;在林下、陡坡、荒坡的生境条件下,植物枝构件构型特征有明显区别,在林下趋于“游击型”,在荒坡和陡坡上趋于“聚集型”。     

低盐度围隔调控系统中浮游植物群落的组成

通过池塘陆基围隔实验,对凡纳滨对虾低盐度(2‰～6‰)调控养殖系统中的浮游植物群落与动态进行了研究。结果表明：低盐度调控实验围隔中共发现浮游植物7门58属86种,其中绿藻50种(丰富度为58.1%)、蓝藻18种(20.9%)、硅藻9种(10.5%)、裸藻4种(4.7%)及隐藻3种(3.5%);主要优势种有美丽胶网藻、狭形纤维藻、栅藻,铜绿微囊藻、拟柱胞藻、梅尼小环藻及尖尾蓝隐藻等;早期优势种多更替快,以绿藻为主,中后期蓝藻占优势,60%围隔以铜绿微囊藻为主要优势种;优势种的平均优势度达到59.6%。浮游植物密度平均2.97×10⁷ cells·L^-1,Shannon-Wiener多样性指数2.18;施有机肥的围隔浮游植物种类丰富,多样性和密度高,群落稳定,有利于对虾健康养殖;大量施用无机肥,易诱发有害微囊藻爆发。     

岩生植物金发草对作物的化感效应

采用生物测定法研究金发草根、茎、叶水浸提液对水稻、小麦、油菜和莴苣等4种受体植物的化感作用。结果表明,金发草根、茎、叶水浸提液对4种受体植物种子萌发和幼苗生长均具化感作用,且随着水浸提液浓度的增高而增强。除水稻外,小麦、油菜、莴苣的发芽速率均受金发草水浸提液的显著抑制,但对最终发芽率影响不显著,说明金发草对植物种子萌发的化感作用主要是延迟种子发芽时间;金发草对作物幼苗生长的化感作用总体上表现为促进地上部分生长而抑制地下部分的生长。受体植物不同发育期对金发草化感作用的敏感程度不同,幼苗期高于萌发期;金发草叶的化感作用最强,其综合效应分别为根与茎的2.14倍和2.56倍。     

PEG胁迫对不同培养方式下金发草愈伤组织再生能力的影响

在静置液体培养和振荡液体培养方式下,研究了聚乙二醇(PEG)胁迫对金发草[Pogona the rumpaniceum(Lam.)Hack]愈伤组织的再生能力和游离脯氨酸(F-Pro)积累的影响。发现金发草愈伤组织具有较高的耐PEG胁迫能力,培养方式与PEG胁迫对其再生抑制上存在时间与程度两个方面的表现。振荡培养方式主要表现为延迟再生时间,而PEG胁迫则主要表现为降低再生频率。两种培养方式都能使愈伤组织在PEG胁迫下发生F-Pro积累,F-Pro含量随PEG浓度的增加和培养时间的增长而升高。去胁迫后,大部分愈伤组织都能够恢复再生能力,F-Pro可能在抑制和恢复过程中作用较复杂。因此,在利用愈伤组织筛选抗旱植株时,PEG浓度应在300g.L-1以上,处理时间3周以上,静置培养更有利于抗旱突变体的筛选。