Performance of polyvoltine silkworm Bombyx mori L. on different mulberry plant varieties

Five cultivated mulberry plant varieties, BSRM‐34, BSRM‐56, BSRM‐57, BSRM‐58 and BSRM‐59, were used to evaluate the effects of plant variety on larval and cocoon characteristics of mulberry silkworm Bombyx mori L. Silkworm larvae undergo their entire larval periods on leaves of mulberry varieties. Different larval characteristics of larval weight, larval length and larval breadth were measured in different growth stages. After rearing, the fifth instar larvae were transferred into a mountage (Chandraki) structure for cocoon rearing for spinning and cocoon production. The cocoons were then harvested and different cocoon characteristics like cocoon weight, shell weight and shell percentage; and other characters like pupal weight and effective rate of rearing were measured. The results showed statistically significant differences among different varieties on larval and cocoon characteristics. The highest performance was observed by feeding the variety BSRM‐34 in respect of the average weight of 10 mature larvae (40.5 g), single mature larval length (7.6 cm) and breadth (1.0 cm), single cocoon weight (1.4 g), shell weight (0.2 g) and pupal weight (1.2 g) while the average performance was recorded by feeding varieties BSRM‐57 and BSRM‐59. The poorest performance was showed by feeding the variety BSRM‐56 (in case of larval characters) and BSRM‐58 (in case of cocoon characteristics). These two varieties also showed the poorest performance for silk yield. Through comparing all the above parameters it was concluded that BSRM‐34 is the best mulberry variety and it is recommended that Bangladeshi farmers adopt that variety for better yield of silk.     

Genome‐wide microarray screening for Bombyx mori genes related to transmitting the determination outcome of whether to produce diapause or nondiapause eggs

The bivoltine silkworm Bombyx mori (Lepidoptera: Bombycidae) exhibits a maternally controlled embryonic diapause. Maternal silkworms decide whether to lay diapause or nondiapause eggs depending on environmental factors such as the temperature and photoperiod during the egg and larval stages, and then induce diapause eggs during the pupal stage. However, little is known about the molecular mechanism that conveys the outcome of whether to produce diapause or nondiapause eggs from the egg or larval stages to the pupal stage. This study used microarray analysis to investigate differentially expressed genes in the larval brains of diapause‐ and nondiapause‐egg producers, to which bivoltine silkworms were destined by thermal or photic stimulation during the egg stage. The cytochrome P450 18a1 and Krüppel homolog 1 genes were upregulated in producers of diapause eggs compared with those of nondiapause eggs under both experimental conditions. Cytochrome P450 18a1 encodes a key enzyme for steroid hormone inactivation and Krüppel homolog 1 is an early juvenile hormone‐inducible gene that mediates the repression of metamorphosis. The upregulation of these genes during the larval stage might be involved in the signaling pathway that transmits information about the diapause program from the egg stage to the pupal stage in the silkworm.     

基于超高效液相色谱-质谱技术对野蚕茧和家蚕茧化学成分进行比较

鉴定并比较野蚕茧与家蚕茧的化学成分对于理解家蚕的驯化具有重要的意义。利用高温高压结合甲醇-水提取的方法获得蚕茧中的化学成分,利用UHPLC-MS技术对野蚕、家蚕大造品种和皓月品种3种蚕茧丝中的小分子成分进行鉴定和比较分析。通过阳离子模式和阴离子模式的UHPLC-MS获得了野蚕、大造和皓月蚕茧丝的代谢指纹图谱,对鉴定到的高丰度化合物进行注释,发现其中包括了氨基酸、黄酮、生物碱、萜类、有机酸和木脂素等成分。PLS-DA的得分图表明,野蚕、家蚕大造品种和皓月品种的3种蚕茧的代谢组存在显著差异。发现脯氨酸、亮氨酸/异亮氨酸和苯丙氨酸在大造茧中的含量显著高于在野蚕和皓月茧中的含量,黄酮类植物次生代谢物在大造茧中的含量显著提高,包括槲皮素、异槲皮素、槲皮素-3-O-槐糖苷、槲皮素-3-O-L-鼠李糖苷、槲皮素-3-O-芸香糖苷和山奈酚;而神经碱、白桥楼碱、毛果芸香次碱、美洲豚草内酯、线叶泽兰素和中缅木莲素等生物碱、萜类和木脂素类的植物次生代谢物在野蚕茧中的含量显著高于在家蚕茧中的含量。在紫外光的激发下观察黄酮的绿色荧光发现家蚕大造茧中的黄酮含量最高,家蚕皓月茧中的黄酮含量最低,而野蚕茧中的黄酮含量居中。生物碱和有机酸是良好的抗虫抗菌剂,它们在野蚕茧中的含量较高,能够提高野蚕茧的防护能力。黄酮类物质在家蚕大造茧中的含量较高,是导致家蚕大造茧呈黄绿色的主要原因。     

应用频数分布面积法定位家蚕QTL

利用生态型差异较大的两个家蚕品种７８２和ｏｄ１００作正反杂交,得到Ｆ１。让Ｆ１雄蚕与叠双隐性标记的ｏｄ１００回 到回交子代。     

Ecdysteroid as a mediator in the regulation of silk protein synthesis and its influence on silkworm (Bom., Lepidoptera) genome

Abstract:  Ecdysteroid is one of the two most important insect hormones, which controls growth and developmental activities of insect. In silkworm, Bombyx mori L., basically ecdysteroid induces molting and metamorphosis in larvae and exogenous administration hastens the silk synthetic activity and cocoon spinning process but it strictly depends on the time of administration. In the present study, we administered phytogenous ecdysteroid to the 48-h-old 5th instar silkworm, B. mori at a single dose of 2  μ g per larva to study its effects on the larval growth, cocoon and silk variables. The possible role of ecdysteroid in altering the developmental sequence of silkworm and thereby its effect on cocoon and silk production at molecular level have been tried to get elucidated. The genomic DNA was isolated from the posterior silk gland on day 5 and 7 of the 5th instar from the ecdysteroid treated and the control larvae and was randomly amplified with arbitrary primers. The result presented notable variation in the amplified product suggesting the participation of ecdysteroid in regulating the silk gene. The feeding period of treated larvae was unaffected while the cocoon characters exhibited considerable improvement. The filament traits also were improved notably in the treated larvae. The participation of ecdysteroid in the silk biosynthetic process with its physiological and molecular implications was discussed.     

He—Ne激光对家蚕诱变效应的研究

采用一定剂量的ＨｅＮｅ激光辐照家蚕蛹,在子代与对照相比较,出现熟性、茧形、斑纹等多种变异,利用ＰＡＧＥ,进行血液蛋白质电泳分析结果,也产生谱带数目及活性的变化,首次证明ＨｅＮｅ激光对家蚕具有一定的诱变效应。     

亚致死剂量阿维菌素和氟虫睛处理小菜蛾对寄生蜂菜蛾绒茧蜂生长发育的影响

分别在小菜蛾体内的菜蛾绒茧蜂处于卵期、早期幼虫和中期幼虫时,饲喂小菜蛾2龄幼虫亚致死剂量（＝LC₁₀）的阿维菌素和氟虫睛,研究上述杀虫剂处理对寄主体内菜蛾绒茧蜂结茧率和羽化率的影响。结果表明： 在菜蛾绒茧蜂处于卵期、早期幼虫和中期幼虫时,饲喂小菜蛾LC₁₀剂量阿维菌素处理的菜叶后,菜蛾绒茧蜂的结茧率分别下降26.6%,22.8%和5.8%,饲喂小菜蛾LC₁₀剂量氟虫睛处理的菜叶后,菜蛾绒茧蜂的结茧率分别下降76.9%,42.5%和18.5%。上述阿维菌素处理对菜蛾绒茧蜂成虫羽化率影响不显著,但上述氟虫睛处理可显著抑制菜蛾绒茧蜂成虫羽化率,在菜蛾绒茧蜂处于卵期、早期幼虫和中期幼虫时,饲喂小菜蛾LC₁₀ 剂量氟虫睛处理的菜叶可导致菜蛾绒茧蜂成虫羽化率分别下降53.1%,36.1%和47.8%。结果显示,即便是对寄主小菜蛾幼虫很低的剂量（LC₁₀剂量）也会显著危害小菜蛾幼虫体内的菜蛾绒茧蜂的生长发育。此外,饲喂小菜蛾幼虫亚致死剂量杀虫剂对菜蛾绒茧蜂生长发育的影响与杀虫剂种类及蛾绒茧蜂发育阶段有关。     

Derivation of economic values for productive and reproductive traits of Bombyx mori (Lepidoptera: Bombycidae) from profit equation

Using a deterministic model of profit equation compatible to cocoon production system in Iran, equations for estimating economic values of cocoon weight, shell weight, shell percentage, fecundity, fertility, and hatchability of three commercial varieties of silkworm Bombyx mori (L.) were derived. Economic values of these traits as well as their relative economic importance (REI) compared with cocoon weight were estimated. Estimates of economic value of a given trait differed among the varieties. Cocoon weight, shell weight, and shell percentage had the highest economic value in variety 107. The highest economic value for fecundity, fertility, and hatchability was estimated in variety 110. Shell weight and shell percentage were the most important production traits, and fecundity was the most important reproduction trait. The REI values of shell weight and shell percentage were higher than that of cocoon weight. The sensitivity of estimated economic values to principal factors of production system was studied by altering cocoon weight, shell percentage, fecundity, variable costs, and cocoon price by +/- 10%. The traits varied in the rate of sensitivity of their economic values to changes in production factors. Economic values of cocoon weight, fecundity, fertility, and hatchability had the most sensitivity to the changes in shell percentage. The most important factor affecting economic values of shell weight and shell percentage was the grade 1 cocoon price. Economic value equations provided in this study can help silkworm breeders to concentrate on the most important factors in predicting the future. Furthermore, when these factors change, silkworm breeders will be able to determine to what extent breeding goals have to change.     

Proteomic analysis of sericin in <Emphasis Type="Italic">Bombyx mori</Emphasis> cocoons

Cocoon sericin plays an important role in the reeling of silk and serves as a valuable biomaterial in the field of biomedicine, skincare, and food industries; however, knowledge about cocoon sericin proteins has been limited. For a comprehensive study on sericin, cocoons of eight varieties of silkworm of different geographic origin and with varied cocoon color were analyzed utilizing proteomics and bioinformatics approaches. The electrophoresis pattern demonstrated some common protein bands for all silkworm varieties and distinctive protein bands for some of those examined in the present study. The Ser2 protein, a new Ser3 protein, and four other novel sericin proteins were identified in cocoons for the first time. Products of both Ser1 and Ser3 genes appear to be ubiquitous in the cocoon shell of Bombyx mori. In addition, cocoons with especially high-reelability produced by the mutant strain B84 had an unique protein product of the Ser2 gene, indicating that the protein may play an important role in cocoon reelability. A series of sequence conflicts and post-translational modifications (PTMs) were also revealed in sericin proteins. Lipid modifications of sericin proteins, which promote waterproofing of the cocoon shell, were observed. Further, hydroxylation was identified, which provided evidence for intermolecular bonds among neighboring molecules of sericin as found in collagens. The sericin proteome data obtained from this study illuminated the molecular complexity of cocoon sericin and contributed to our understanding of the properties of sericin in filature and biomaterials.     

家蚕酪氨酸羟化酶基因BmTh的表达及功能

酪氨酸羟化酶作为儿茶酚胺合成的限速酶, 广泛存在于昆虫、哺乳动物和人类中, 是其新陈代谢不可缺少的酶类。在其他昆虫中, 酪氨酸羟化酶参与了黑色素的合成, 并在昆虫外骨骼的硬化过程中发挥关键作用。为了研究家蚕Bombyx mori酪氨酸羟化酶基因的生理生化功能, 本文对其基因结构、表达特征及功能进行了研究。基于家蚕基因组和基因芯片数据的生物信息学分析表明, BmTh位于家蚕1号染色体上, 含有8个外显子, 编码561个氨基酸。基因芯片数据显示在家蚕5龄第3天的头部和体壁组织中的表达量较高, RT-PCR验证结果与此一致。利用石蜡组织切片材料和RNA探针对BmTh进行表达定位, 原位杂交结果显示在家蚕头部边缘和体壁上有明显的杂交信号。在幼虫发育至熟蚕时注射酪氨酸羟化酶抑制剂3-indole-L-tyrosine （3-IT）, 20 mmol/L的浓度对幼虫几乎没有影响, 50 mmol/L的浓度导致幼虫变态不完全和化蛹困难, 100 mmol/L的浓度使幼虫致死且体色变黑。结果提示, BmTh对家蚕变态发育起重要作用, 是家蚕正常发育不可缺少的关键基因。     

Biological relevance of host plant-derived terpenoid in the cocoons of the tropical tasar silkworm Antheraea mylitta

We have characterized and studied the biological functions of a terpenoid derivative in the Indian tropical tasar silkworm, Antheraea mylitta reared on the primary host plant Arjun, Terminalia arjuna. The compound from insect cocoon turned out to be a terpenoid derivative which resembled oleanane type triterpene (Arjunolic acid) present in the host plant. The plant and cocoon compounds were anti-oxidative as determined by bleaching of beta carotene in vitro. UV-exposure is the major form of peroxidative insult encountered by this wild tropical silkworm. The life cycle comprising five larval stages and the cocoon stage lasts for about 30–45 days. Hence the sequestration of antioxidant and UV-protectant molecule from the host plant commands great biological significance.     

Role of specific activators of intestinal amino acid transport in Bombyx mori larval growth and nutrition.

Nutrient absorption and its modulation are critical for animal growth. In this paper, we demonstrate that leucine methyl ester (Leu-OMe) can greatly increase the activity of the transport system responsible for the absorption of most essential amino acids in the larval midgut of the silkworm Bombyx mori. We investigated leucine uptake activation by Leu-OMe in brush border membrane vesicles and in the apical membrane of epithelial cells in the midgut incubated in vitro. Moreover, the addition of this strong activator of amino acid absorption to diet significantly affected larval growth. Silkworms fed on artificial diet supplemented with Leu-OMe reached maximum body weight 12-18 h before control larvae, and produced cocoon shells up to 20% heavier than those of controls. The activation of amino acid absorption plays an essential role in larval development so that larval growth and cocoon production similar to controls reared on an artificial diet with 25% of dry mulberry leaf powder were observed in silkworms fed on an artificial diet with only 5% of mulberry powder. Arch.     

转蜘蛛拖牵丝蛋白基因家蚕蚕丝氨基酸组成及其机械性能

将以绿色荧光蛋白基因为报告基因、含有人工合成的1.6 kb的蜘蛛拖牵丝蛋白基因及转座子pig-gyBac的转基因载体成功导入减秋无滞育家蚕受精卵,得到转蜘蛛拖牵丝蛋白基因家蚕及绿色荧光茧。对转基因家蚕与对照家蚕丝素蛋白进行了氨基酸组成分析,结果表明转基因蚕茧丝素蛋白甘氨酸和丙氨酸的百分含量分别增加了1.65%和1.80%(平均值);对其生丝的机械性能进行了测试研究,结果表明转基因蚕茧生丝的伸长率降低,断裂强度和初始模量增加,且差异均显著,与理论预期结果吻合。结果表明转基因家蚕蚕丝的机械性能一定程度上得到了提高。     

室内饲养红棕象甲的行为观察

报道红棕象甲Rhynchophorus ferrugineus Fab.成虫交配、产卵行为,描述在交配和产卵过程中发生的多种行为。红棕象甲整日均可见其交配行为,但在暗光周期开始0.5h左右明显有一个交配高峰期。其交配持续时间、交配几率不受虫体大小的影响。在无外界因子干扰的条件下,交配持续时间均可达1min。红棕象甲卵为单产,一处1粒,主要是通过口喙蛀孔辅助完成;观察红棕象甲幼虫、蛹的行为,例如取食、争斗、蜕皮、做茧等行为。且随着低龄幼虫向高龄幼虫的过渡,幼虫的取食和钻蛀行为从棕榈植物中心向外围扩散。通过摇动或震动茧后红棕象甲在其中表现的行为,并结合茧的颜色和质地可准确判断茧中存在的3种虫态。     

环境激素邻苯二甲酸丁基苄酯对家蚕生殖的影响

为了探讨环境激素邻苯二甲酸丁基苄酯(Butyl Benzyl Phthalate,BBP)对家蚕(Bombyx mori)等鳞翅目昆虫的生殖损伤,家蚕饲以不同浓度BBP喷洒后的桑叶,调查了BBP对家蚕造卵、产卵等生殖机能的影响。结果表明:BBP影响家蚕的体重增加、存活率及产卵特性,随着BBP浓度的增加,影响逐渐加大,1.6 mmol/L添食5龄起蚕时,造卵数及产卵数仅为对照的56.1%和51.4%,对受精及孵化等的影响具有相同变化趋势,只是对雄性的影响大于雌性;不同时期的添食结果表明,BBP对家蚕生殖的影响:3龄起蚕4龄起蚕5龄起蚕,0.16 mmol/L添食时,造卵数及产卵数分别只有对照区的57.5%、66.3%、97.6%及58.7%、74.1%、96.0%;BBP添食对存活下来的个体的下一代的茧质几乎没有影响。由以上结果表明:BBP对家蚕的生殖具有明显的毒害作用,BBP添食浓度越高,接触时间越早,在蚕体内积累越多,产生的生殖毒性就越大,而且这种毒性雄性大于雌性。     

不同石榴品种对井上蛀果斑螟生长发育和繁殖的影响

井上蛀果斑螟是云南石榴上的一种主要蛀果害虫.为明确石榴不同品种对该虫生长发育和繁殖的影响,在温度(25±1) ℃、光周期15 L∶9 D、相对湿度(70±10)%条件下,系统观察了井上蛀果斑螟在甜绿籽、厚皮甜沙籽、甜光颜、酸绿籽和酸沙籽5个品种上的发育历期、存活率和产卵量等生物学特性,并组建了其实验种群生命表.结果表明: 井上蛀果斑螟在5个石榴品种上的卵期、幼虫期、蛹期、雄成虫寿命、全世代历期及卵孵化率均无显著差异;预蛹期、雌成虫寿命、幼虫存活率、化蛹率、羽化率、总成活率、单雌产卵量及雌雄蛹质量存在显著差异,除幼虫存活率外,均以酸绿籽种群较高,厚皮甜沙籽种群次之,二者间差异不显著.生命表参数表明,净增殖率、内禀增长率和周限增长率均为酸绿籽种群显著高于甜绿籽、甜光颜和酸沙籽种群,但与厚皮甜沙籽种群差异不显著;平均世代周期各品种间无显著差异;种群加倍时间为酸绿籽种群显著小于其余4个品种.5个石榴品种中,酸绿籽和厚皮甜沙籽较适宜井上蛀果斑螟的生长发育和繁殖.     

Application of Multi-vitamins as Supplementary Nutrients on Biological and Economical Characteristics of Silkworm Bombyx mori L

In order to investigate the effects of supplementary nutrients on silkworm, Bombyx mori, an experiment was conducted with multi-vitamins treatments. Leaves enriched with multi-vitamins (1, 2.5 and 5%) were fed once a day to 4th and 5th instar silkworm larva. The supplementation of the leaves was done by spraying the treatments on them. These treatments resulted in a significant increase in biological and economical parameters such as larval weight, female and male cocoon weight, pupal weight and egg productivity when compared with normal control. Multi-vitamins of 2.5% treatment increased the larval weight by 10.2%, which had the most weight enhancement in the fifth day of 5th instar larvae. However, 5% concentration of multi-vitamins decreased some biological characteristics. These treatments resulted in 4.7% increase of cocoon's weight. In most of the moths the number and weight of eggs had significant difference compared to control, but these supplementary materials caused relatively less egg hatching.     

Molecular markers (RAPD) associated with growth, yield and origin of the silkworm, Bombyx mori L. in India

To identify the molecular markers associated with growth and yield parameters in silkworm, Bombyx mori, RAPD profiles generated with seven UBC primers for fourteen silkworm stocks, originated from China, Japan, India and Russia, were statistically analyzed. Stepwise Multiple Regression Analysis establishes significant association of 45 markers with larval span, growth indices and four cocoon yield parameters relevant for silk production and t-test attest significance of the association of 89.5(1500 bp) and 54.13(300 bp), respectively with longer larval duration and high cocoon weight. The validity of this selection of markers was further supported with Discriminant Function Analysis (DFA) done on the basis of Mahalanobis D2 statistics. The two indices of yield/growth were also tested with DFA, which helped in identifying a few markers and thereby opened scope of using such marker (e.g. 91.11(900 bp)) for incorporating molecular markers in the breeding program for crop improvement in silkworm.     

In-situ observation of tryptophan in larval cocoon silk of the hornet Vespa simillima xanthoptera cameron by ultraviolet resonance raman spectroscopy

We performed in-situ ultraviolet resonance Raman (UVRR) spectroscopy of the larval cocoon silk of the hornet, Vespa simillima xanthoptera Cameron, and compared the result with that of the silkworm, Bombix mori. The UVRR spectrum of the hornet cocoon differed markedly from that of the B. mori cocoon: peaks attributable to tyrosine (Tyr) were observed strongly, and tryptophan (Trp) peaks weakly, in the spectrum of the B. mori cocoon, whereas peaks attributable to Trp exclusively appeared in the spectrum of the hornet cocoon.     

Effects of optimum doses of nitrogen,phosphorus, potassium and calcium on silkworm,Bombyx mori L., growth and yield

Silkworm rearing has been an income source for small-holding farmers in Pakistan. Over the years efforts have been made to improve silkworm quality and quantity and thus develop better prospects for increasing yield and income. Mulberry leaves Morus alba L. in a series of experiments have been supplemented with various nutrients in different doses and combinations. Relative success has been achieved in this context. In our present experiments on silkworm Bombyx mori L., we fed the larvae on mulberry leaves supplemented with different doses of N (0.2%), P (0.1%), K (0.3%) and Ca (0.1%) at 26 ± 3°C with 65 ± 5% relative humidity. The results showed better outputs in terms of food consumption (72.55 g/10 larvae), coefficient of utilization (76.45%), body weight (70.07 g/10 larvae) and body length (8.56 cm/larvae) than where simple mulberry leaves were offered. Our net gains with these production parameters have been in terms of heavier cocoons with and without pupa (2.25 and 0.69 g/cocoon), respectively.