果蝇实验中海绵塞及移蝇漏斗的制作

果蝇实验是最常见的生物学实验,实验中往往需要大量的瓶塞。介绍如何用电热丝切割器自制美观、易于清洗与保管的海绵塞,并介绍一种在海绵塞的基础上略加改造,用于转移果蝇的小装置——移蝇漏斗。使用这种小装置可以在瓶内果蝇不外飞的情况下,方便地往己收集了一些处女蝇的培养瓶中转移新收集的处女蝇。     

关于遗传学实验教学中果蝇实验的改革探索

介绍了遗传学实验教学中果蝇实验的教学改革尝试。一方面,将不同研究水平的实验集中连续交叉开出,充分利用实验时间,增选实验内容,改进实验方法,培养学生的综合能力;另一方面,讨论遗传学实验教学如何改变“验证性”教学为“发现式”教学。在果蝇杂交实验教学中,由学生提出实验设计方案,独立完成实验内容,学生处于主体地位,从而培养学生独立思考和实际操作能力,激发学生的学习兴趣。     

果蝇唾液腺染色体观察实验的改进

《全日制中学生物学教学大纲》明确规定 :使学生掌握关于染色体、DNA和基因三者之间的相互关系的知识以及基因的概念。笔者在高中生物学教学中利用果蝇三龄幼虫作实验材料 ,并对该实验步骤进行了一些探索和改进 ,在指导学生理解和掌握染色体、DNA与基因的相互关系的知识方面 ,取得了较好的教学效果 ,具体作法如下 :1　实验原理染色体的数量和形态特征跟生物体的性状遗传有着密切的关系 ,而染色体的形态特征又不易观察 ,科学家们发现果蝇三龄虫的唾液腺细胞处于永久早期 ,染色体解旋呈伸展状态。在幼虫发育过程中细胞核中的DNA多次复制 ,…     

摩尔根果蝇杂交实验的科学逻辑思维

将摩尔根"果蝇的限性遗传"原文重要部分翻译为中文并对摩尔根果蝇眼色杂交实验的科学逻辑思维进一步加以解析,以帮助师生理解摩尔根作出红眼基因位于X染色体上的推论,以及Bridges推断Y染色体上没有红眼基因的实验证据和逻辑依据,对学生严谨科学思维的发展和教师的教学起到启发和借鉴作用.     

打开经典实验的问号——以摩尔根果蝇杂交实验为例

在实际教学中,对教材所描述的"摩尔根的果蝇交配实验"存有不少疑惑。从最初发现的白眼果蝇进行了几次交配、摩尔根通过哪种测交进一步验证了假设、如何理解白眼的遗传与X染色体遗传相似等3个方面着手,尝试解开该经典实验的问号。     

“摩尔根的果蝇杂交实验(第2课时)”教学设计

本节课的教学设计以新课程理念作为主要的指导思想,根据学生的具体情况和学校的教学资源,为学生创设了以假说-演绎法分析果蝇眼色遗传为主线、亲身参与果蝇杂交实验的基本过程,为载体的探究性学习课程。     

低温推迟果蝇交配行为的研究

通过不同温度对果蝇羽化至交配时间的影响试验,发现在5℃、10℃条件下果蝇雌雄混存, 处女蝇的安全期可由8 h分别延长到72 h、48 h以内。     

果蝇饲养管理的几个问题

1 防止培养基长霉 当外界温度不适应果蝇生长时(温度低于18℃)．培养基接种后的7d内,特别容易长霉。要避免长霉,应注意：①培养果蝇用的器皿要严格消毒。培养瓶洗干净后,自然凉干,再与棉塞一道进行高温干燥灭菌(120℃,30min)。②培养基要营养全面。果蝇培养基的种类很多,本实验室用的是玉米培养基,配方及配料如下：水750mL煮开,加琼脂6．2g,待琼脂溶解后加白糖62．5g,搅拌溶解后再加调成糊状的玉米糊(玉米82．5g．用冷水调成糊状,     

鹌鹑、果蝇遗传实验价值的比较研究

果蝇是生物学科遗传实验的经典材料,鹌鹑是新近开发的实验动物。对两者的实验价值进行比较研究结果表明：果蝇具有生活史短、繁殖率高、性状突出,在教学实验中还表现出知识性强,实验面宽等特点;鹌鹑具有直观性强、时代间隔短、繁殖率高、贴近生活、服务生产、供人观赏、饲养简便、遗传性状突出、知识性强等特点。同时,两者也都有不足。通过比较研究为合理安排生物实验课,进行校本实验开发提供科学依据。     

Don't pull the plug! the Drosophila mating plug preserves fertility

ABSTRACT

Mating plugs are hardened structures—typically a coagulation of seminal fluid components—that are transferred to, or formed within, the female reproductive tract of numerous animal species (both mammals and insects). Analysis of the role(s) of the mating plug in reproduction has been conducted in a wide array of diverse species. These structures have been proposed to have a multitude of functions, which include altering female re-mating rate, acting as a barrier to re-mating and being required for sperm storage or sperm movement to occur in mated females. A recent analysis of the Drosophila melanogaster mating plug has shown that proper formation of the structure is required for optimal fertility in flies: the Drosophila mating plug is required to retain the ejaculate within the female reproductive tract once mating has terminated. Here, we discuss the possible implications of the Drosophila mating plug in the fertility of this species in light of these new results.     

Harvesting and Preparing Drosophila Embryos for Electrophysiological Recording and Other Procedures

Drosophila is a premier genetic model for the study of both embryonic development and functional neuroscience. Traditionally, these fields are quite isolated from each other, with largely independent histories and scientific communities. However, the interface between these usually disparate fields is the developmental programs underlying acquisition of functional electrical signaling properties and differentiation of functional chemical synapses during the final phases of neural circuit formation. This interface is a critically important area for investigation. In Drosophila, these phases of functional development occur during a period of <8 hours (at 25°C) during the last third of embryogenesis. This late developmental period was long considered intractable to investigation owing to the deposition of a tough, impermeable epidermal cuticle. A breakthrough advance was the application of water-polymerizing surgical glue that can be locally applied to the cuticle to enable controlled dissection of late-stage embryos. With a dorsal longitudinal incision, the embryo can be laid flat, exposing the ventral nerve cord and body wall musculature to experimental investigation. This system has been heavily used to isolate and characterize genetic mutants that impair embryonic synapse formation, and thus reveal the molecular mechanisms governing the specification and differentiation of synapse connections and functional synaptic signaling properties.Open in a separate windowClick here to view.^{(51M, flv)}     

The DOCK protein sponge binds to ELMO and functions in Drosophila embryonic CNS development

Cell morphogenesis, which requires rearrangement of the actin cytoskeleton, is essential to coordinate the development of tissues such as the musculature and nervous system during normal embryonic development. One class of signaling proteins that regulate actin cytoskeletal rearrangement is the evolutionarily conserved CDM (C. elegansCed-5, human DOCK180, DrosophilaMyoblast city, or Mbc) family of proteins, which function as unconventional guanine nucleotide exchange factors for the small GTPase Rac. This CDM-Rac protein complex is sufficient for Rac activation, but is enhanced upon the association of CDM proteins with the ELMO/Ced-12 family of proteins. We identified and characterized the role of Drosophila Sponge (Spg), the vertebrate DOCK3/DOCK4 counterpart as an ELMO-interacting protein. Our analysis shows Spg mRNA and protein is expressed in the visceral musculature and developing nervous system, suggesting a role for Spg in later embryogenesis. As maternal null mutants of spg die early in development, we utilized genetic interaction analysis to uncover the role of Spg in central nervous system (CNS) development. Consistent with its role in ELMO-dependent pathways, we found genetic interactions with spg and elmo mutants exhibited aberrant axonal defects. In addition, our data suggests Ncad may be responsible for recruiting Spg to the membrane, possibly in CNS development. Our findings not only characterize the role of a new DOCK family member, but help to further understand the role of signaling downstream of N-cadherin in neuronal development.     

Pilot-scale experiment of down-flow hanging sponge for direct treatment of low-strength municipal wastewater in Bangkok,Thailand

A pilot-scale experiment of a down-flow hanging sponge (DHS) reactor for treatment of low-strength municipal wastewater was conducted over 1 year in Bangkok, Thailand, to establish an appropriate method for treatment under tropical climate conditions. Municipal wastewater with an average BOD of 19 mg/L was fed directly into the DHS reactor. Superior effluent quality (5.1 ± 3.4 mg/L TSS, 21.1 ± 9.0 mg/L COD, 2.8 ± 1.4 mg/L BOD, and 4.1 ± 1.0 mg/L TN) was achieved at a hydraulic retention time (HRT) of 1 h under an average temperature of 30 °C. The DHS reactor reached an actual HRT of 19.0 min, indicating good contact efficiency between wastewater and retained sludge. The DHS reactor retained dense sludge at 15.3–26.4 g VSS/L based on the sponge media volume. The sludge activity in terms of specific oxygen uptake rate was good. Excess sludge was produced as 0.051 g TSS/g COD removed (0.11 g TSS/g BOD removed), and a good SVI of 28 mL/g was observed. The sufficient performance was attributed to dense sludge with high activity, regardless of the low-strength wastewater. Overall, the DHS was advantageous owing to its simple operation, lack of operational problems, and low power consumption.     

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