蚱蝉(Cryptotympana atrata Fabricius)发声器结构:发声膜与鸣声

蚱蝉单发声膜发出的click声波形由高幅值和低幅脉冲列(pulse train,PT)组成.高幅值PT含脉冲越多,主峰频率(main peak frequency,MPF)就越高.本文进一步阐明:1、高幅值PT多含有11个脉冲,当含有1,2,3个时,脉冲个数与MPF成准线性关系 超过三个为非线性关系.2、双发声膜发声的频带主要在2700Hz-6700Hz之间.数个click声组成的波形中,低幅值PT功率谱包络波近似于标准高斯型,MPF约为4900Hz;不同高幅值PT内含主脉冲的频率不同是MPF变化的主要因素.3、蚱蝉鸣声功率谱主要有三个子谱区A,B,及C,对应的频带依次约为2700Hz—3700Hz,3700Hz-5700Hz,及5700Hz—6700Hz.     

鸣鸣蝉(Oncotympana maculaticollis Motschulsk)自鸣声信息及其频谱的双倍频特征

本文报道庐山鸣鸣蝉自鸣声信息的长码与短码结构及其部分频谱的双倍频特征。庐山鸣鸣蝉多次重复的“MUYING……MUYING MU A”叫声,仅由三种信息MU(简称M),YING(I)及“A”重复编排而成。M与A的特征类似:持续时间大于170ms,波形具有约为6ms的周期,频谱主峰频率(MPF)约为4kHz,谱能量主要分布在2—7kHz频带内。这是鸣鸣蝉自鸣声长码的近似不变特征。长码I与M,A的不同点是持续期多在300ms以上,MPF为变频特征,在2.7—7.2kHz之间变化,谱能量较均匀地分布在0—14kHz频带内。约为6ms的准周期内含有几个频率不同的脉冲串(PT),这些不同频率的PT称为短码。这表明鸣鸣蝉自鸣声中长码是由变频短码组成的。M与A部分频谱具有双倍频特征,即构成频谱的子谱峰频率为两个倍频序列,其中一序列的共振峰为主峰,另一序列的共振峰为次峰。     

鸣鸣蝉发声肌的结构观察

鸣鸣蝉Onvotympana maculaticollit Motsch的发声肌平均含193个初级肌束,多数初级肌束含9-10条肌纤维,其顶、底瑞的附着结构仅由柱状粘和细胞层组成。每条肌纤维约含1 900根肌原纤维,多数肌原纤维的长,宽和截面分别约0.77μm、0.68μm和0.53μm².井约含200根粗肌丝,其粗细肌丝的比值一般为3∶1。肌小节的长度和z线的宽度分别约3μm 和0.2μm.三联管分别位于距两端z线约0.75μm处。肌原纤维、线粒体和微气管-肌质网的面积系数分别约31.3%、46.O%和11.9%。肌小节中粗肌丝纵贯两端z线,中间无1带;细肌丝由z线相向延伸到肌小节中央,其空区约0.15-0.25μm,并无M线。这些结构特征不仅使发声肌能够利用有限的几何空间产生最大的张力,并可适应高速串的收缩运动。     

黑蝉(C.atrata Fabricius.)鸣声的方向性和第三气门的功能

黑蝉鸣声的波形结构无明显的方向性.单音节的重复周期和调幅脉冲列的间隔(I_1和I_2)分别为9.787±0.813ms、2.286±0.093ms和1.874±0.063ms.幅值特性有明显的方向性.主峰频率(MPF=5.47±0.11kHz)的幅值,头向和背向分别比尾向下降5.9dB和3.9dB,侧向和腹向分别增高1.1dB和2.3dB.两侧第三气门受阻后鸣声的波形结构和音色都产生明显变化.I_1和I_2分别为0.912±0.156ms和1.099±0.113ms,约为正常值的40—59%.有三个谱带,MPF为5775Hz,两侧谱带的峰值频率为4575Hz和7025Hz,分别下降1.5dB和3.4dB.     

刺激家鸽中脑丘间复合体背内侧核诱发叫声与其自鸣声的比较

利用计算机声谱分析技术比较了家鸽刺激中脑丘间复合体背内侧核(DM)诱发叫声和其正常自鸣声。家鸽的单次自鸣声“di·Gu—”,包括前奏、高潮声和尾声,其主频率和相对幅值都呈明显的逐步递增、平稳和逐步下降过程。高潮声平稳期的载波主频率(318Hz)所表征的主音调比前奏和尾声的主频率(239Hz)分别平均高4.9个半音,相对幅值分别平均高24.4dB和13.2dB,品质因数(Q6dB)分别增高1.8倍和2.8倍。随着刺激电压的增大和减小,家鸽单次鸣声持续时间呈显著的线性递减和递增。诱发叫声的主频率显著性低于自鸣声,声图中有1-2个陪音。本实验为阐明非鸣禽发声调控提供声学特征上的依据     

黑蚱蝉鸣声的结构和音色特征

本文对北京、河北和福建等地黑蚱蝉(Cryptotympana atrata Fabricius)的三种鸣声进行了分析,并对发声机理进行了讨论。 黑蚱蝉野外的自然鸣声具有基本相同的结构层次,都由重复频率为43—49Hz的节奏组成,每个节奏含有4个单音节,每个单音节含有3个脉冲群,每个脉冲群含有若干个脉冲。但是音色有明显的差异,即分别为单音色、双音色和具有高幅低频声的复合声。黑蚱蝉室内的惊鸣声和自鸣声,虽然音色有一定的变化,但仍保持自然鸣声的结构层次。鸣声的结构层次明显取决于发声膜的结构特征,这表明具有种类的特性。音色的差异性不仅与调音、扩音结构的功能有关,而且可能与发声膜的力学性质和发声的原初过程有关,即可能具有地区性和种下差异。 这些结果可为蝉类发声机制和有害昆虫声引诱的声学模型的研究提供依据。     

鸣鸣蝉（Oncotympana maculaticollis Motsch）发声肌中肌原纤维的双阵列结构及莫发声原初过程的分析

给出了鸣鸣蝉发声肌肌原纤维的双阵列结构,其肌纤维中并存两种不同阵列的“快”和“慢”动肌原纤维（ＦＳＭ和ＳＳＭ）．ＦＳＭ和ＳＳＭ虽然由粗肌丝构成相同的阵列骨架,但细肌丝对粗肌丝的比例（ＲＴＩＦ）不同,分别为３：１和５：１．明显区别于单音调鸣声的蝉类发声肌肌原纤维的ＲＴＩＦ为３：１的单阵列结构,即与鸣鸣蝉变音调声产生的原初机制相适应．     

鸣叫雄蝉的听觉反应及其与发声的内源关系

黑蚱蝉 (C .atrata Fabr.)的静息雄蝉对 70dB(SPL)左右的刺激声脉冲反应的听神经复合动作电位 (简称“听神经电位”)的潜伏期和幅值分别平均为 ( 3 .92±0 .2 8)ms和 ( 0 .32± 0. 2 2 )mV ,鸣叫雄蝉虽对外部刺激声脉冲基本无反应 ,但对耦合在刺激声脉冲中的叫声脉冲有敏感反应 ,听神经电位的潜伏期和幅值分别为 ( 4 .1 6±0 .43)ms和 ( 0 .46± 0 .2 5 )mV .鸣叫雄蝉听神经电位前的负电位表征了发声与听觉神经回路之间存在内源联系 .     

蝉的变音调复合声和发声机制的分析

蛙鸣蝉(Meimuna opalifera (Walk).ab.punctata Kato)的自然鸣声为“ji…guái”的重复单变调复合声.“ji”为主音频约4800Hz的准单音;“guái”的波形和主音频呈明显的演变,优势主频约2100Hz和2800Hz的变音调声.鸟鸣蝉(Meimuna opalifera (Walk)var.formosana Kato)的自然鸣声由重复的“jiū…ruǎ”和“jiū…gū…”合成的双变调复合声.“jiū”为基频和主频分别约625Hz和2100—2300Hz的准单音;“ruǎ”的波形和主音频呈明显的演变,基音和优势主频分别约575—625Hz和1550—1750Hz的变音调声.“gū”为优势主频约625Hz的准单音.变音调复合声不仅与腹部运动有关,而主要取决于发声肌的收缩特性和发声膜肋结构的振动特性.     

云南景洪地区蝉鸣特点的分析

本文对云南景洪地区三种蝉:A.周氏尖瓣蝉Acutivalva chotti Yao,B.大狭瓣蝉Aola bindusara Distant,C.中华舌瓣蝉Linguvalva sinensis Chou et Yao的鸣声特点,及其晨鸣进行了分析。 蝉A和蝉B的鸣声都是由主峰频率为6.3 kHz的单次声群(SSG)和连续声群(CSG)组成的节律声。但是蝉A鸣声的节律平均周期、SSG中单次声的个数和CSG中调幅脉冲列的重复频率等都明显地与蝉B有区别。蝉C的鸣声是由重复频率约120Hz的调幅脉冲列组成的连续声,其主峰频率为5kHz。 蝉B的傍晚鸣声与午间鸣声相比较,其CSG中调幅脉冲列的重复频率和主峰频率等都是相同的,仅仅是节律的平均周期延长1.7秒,1/3倍频谱中低于1,000Hz的各个频率幅值明显下降。 这三种蝉晨间群鸣由前奏、高潮声和尾声组成。高潮声开始于6点(28±2)分,尾声终止于6点(43±2)分,是以24小时为周期的生物钟现象。 这些结果可能为蝉科分类和蝉的声通讯研究提供某些参考。     

Auditory response and intrinsic link with sound-production in singing male cicada

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Phonotaxis in <Emphasis Type="Italic">Hyla versicolor</Emphasis> (Anura,Hylidae): the effect of absolute call amplitude

The influence of call amplitude on phonotaxis in female Hyla versicolor was studied using a no-choice paradigm. One set of experiments estimated effects of stimulus amplitude on phonotaxis toward a synthetic model of a conspecific call. The response strength increased with amplitude from the behavioral threshold (37–43 dB SPL) up to 79 dB SPL and then decreased at higher amplitudes. Females approached the loudspeaker with short walking bouts (1 s duration) occurring immediately after call presentations. Increase in response strength was attributed to an increasing proportion of calls that elicited such walking bouts, whereas the decrease at high amplitudes resulted from decreasing distance covered per bout. The quality of orientation remained constant for all above-threshold amplitudes. A second set of experiments tested the selectivity for interval duration and pulse duration at amplitudes of 55, 70, and 85 dB SPL. Selectivity for both parameters was similar at 70 and 85 dB SPL, but tended to increase at 55 dB SPL. The results suggest that selective phonotaxis in H. versicolor is not adapted for long-distance communication. This finding differs from those of comparable studies of acoustic insects.     

Gold Toning Improves the Visualization of Nucleolar Organizer Regions in Paraffin Embedded Tissues

A modification of the silver colloid technique for staining nucleolar organizer regions in paraffin embedded tissues is described. This modification involves the application of a gold toning step with subsequent gold reduction, if necessary, following incubation of sections in the standard silver colloid solution. Silver stained nucleolar organizer regions (AgNORs) in toned sections are more sharply delineated when compared to untoned controls. in high grade tumors the addition of the toning step results in significantly higher AgNOR counts due to the ability to discriminate more easily individual AgNORs in argyrophilic aggregates within the nucleus. It is recommended, because of enhanced visualization, that this modification of the silver colloid technique be used in studies involving quantification of AgNORs in tissue sections.     

Gold Toning Improves the Visualization of Nucleolar Organizer Regions in Paraffin Embedded Tissues

A modification of the silver colloid technique for staining nucleolar organizer regions in paraffin embedded tissues is described. This modification involves the application of a gold toning step with subsequent gold reduction, if necessary, following incubation of sections in the standard silver colloid solution. Silver stained nucleolar organizer regions (AgNORs) in toned sections are more sharply delineated when compared to untoned controls. in high grade tumors the addition of the toning step results in significantly higher AgNOR counts due to the ability to discriminate more easily individual AgNORs in argyrophilic aggregates within the nucleus. It is recommended, because of enhanced visualization, that this modification of the silver colloid technique be used in studies involving quantification of AgNORs in tissue sections.     

Intracellular transport and metabolism of sphingomyelin

SM is unique among the phospholipids because it is restricted to the lumenal aspect of organelles involved in the secretory and endocytic pathways. Given the intracellular sites of SM biosynthesis and hydrolysis, and the interconnections between these sites by vesicle-mediated transport pathways, the basic mechanism for maintaining the intracellular distribution of SM seems clear. It remains to be determined how SM metabolism and transport are coordinated to maintain the SM content of each organelle. For example, the size of the SM pool at the cell surface is maintained by regulation of at least five processes: transport of newly synthesized SM from the Golgi apparatus, plasma membrane lipid recycling, local SM synthesis, local SM hydrolysis, and SM transport from the cell surface to lysosomes. Although SM cannot undergo spontaneous transbilayer movement, SM metabolism generates both DAG, Cer and (indirectly) SPhB which can rapidly 'flip-flop', and thus gain access to the cytoplasmic leaflet of a membrane. It is of particular interest that these lipid species may be involved in the regulation of PK-C, suggesting that SM metabolism could play a role in signal transduction. However, physiological effects of endogenous Cer and SPhB remain elusive, even though the pharmacological effect of SPhB on PK-C is well established. Aside from the direct generation of second messengers, stimulation of SM hydrolysis has also been shown to induce cholesterol movement from the cell surface to intracellular membranes. It is not known whether this reflects the possibility that cholesterol may act as a second messenger. Alternatively, this phenomenon suggests that SM metabolism may cause rapid changes in the physical properties of the cell surface. For example, erythrocytes extensively treated with exogenously-added SMase will undergo endovesiculation It is tempting to speculate that any involvement of SM in the regulation of intracellular processes requires a combination of both the generation of biochemical second messengers and the alteration of membrane biophysical properties that can result from SM metabolism.     

Multiple membrane tethers probed by atomic force microscopy

Using the atomic force microscope to locally probe the cell membrane, we observed the formation of multiple tethers (thin nanotubes, each requiring a similar pulling force) as reproducible features within force profiles recorded on individual cells. Forces obtained with Chinese hamster ovary cells, a malignant human brain tumor cell line, and human endothelial cells (EA hy926) were found to be 28 +/- 10 pN, 29 +/- 9 pN, and 29 +/- 10 pN, respectively, independent of the nature of attachment to the cantilever. The rather large variation of the tether pulling forces measured at several locations on individual cells points to the existence of heterogeneity in the membrane properties of a morphologically homogeneous cell. Measurement of the summary lengths of the simultaneously extracted tethers provides a measure of the size of the available membrane reservoir through which co-existing tethers are associated. As expected, partial disruption of the actin cytoskeleton and removal of the hyaluronan backbone of the glycocalyx were observed to result in a marked decrease (30-50%) in the magnitude and a significant sharpening of the force distribution indicating reduced heterogeneity of membrane properties. Taken together, our results demonstrate the ability of the plasma membrane to locally produce multiple interdependent tethers-a process that could play an important role in the mechanical association of cells with their environment.     

楝星天牛胸部摩擦和鞘翅振动发声及其声学特性的研究*

楝星天牛Anoplophora horsfieldi(Hope)成虫可借两种不同的方式发声： 1.胸部摩擦发声;2.鞘翊振动发声。胸部摩擦发声可连续进行,具有抗拒敌害和种内通讯的生物学意义;鞘翅振动发声为断续产生,受外界刺激而诱发,主要与抗拒敌害有关。测定表明,胸部摩擦声由多个音组连续组成,每一音组的持续时间为1100-1 6000ms,依次由抬头声音节(持续384±22ms,含有250-350个脉冲列)、间隔1(270-600ms)、低头声音节(382±16ms,250-350个脉冲列)和间隔2(80-360ms)组成。 抬头声音节的功率谱由基本音及其分音组成,基本音为信号能量的主要部分,其主峰频率为742±30Hz(雄)和603±34HZ(雌)。鞘翅振动声由间隔不等的,7-9个脉冲列组成,脉冲列的振幅较大、频率较高,持续约7-10ms。功率谱图上虽然脉冲列的频率分布于0-3100Hz,但能量主要集中在850-1050Hz内。与胸部摩擦声相比,鞘翅振动声的能量更高、释放更突然,是一种更为有效的拒敌性行为。     

Synthesis and transport of different sphingomyelin species in rat Sertoli cells

Cellular phospholipids of Sertoli cells from immature rats were labeled with [¹⁴C]-choline. Two sphingomyelin bands (SM1 and SM2) were identified by TLC. The incorporation of [¹⁴C]-choline over a 45 h period of incubation demonstrated that there are differences in labeling kinetics between SM1 and SM2. The subcellular location of SM1 and SM2 was investigated by accessibility to bacterial sphingomyelinase. The results showed the existence of two SM pools in Sertoli cells, but an equal cellular distribution of SM1 and SM2. SM2 is characterized by a relatively high content of unsaturated fatty acids. The inhibition of vesicular flow by monensin determines a decrease of about 60–70% in incorporation into SM1 and SM2, suggesting the existence of at least two sites of sphingomyelin synthesis. Pulse-chase and time-course experiments indicated a phosphatidylcholine SM precursor product relationship and differences in kinetic properties between SM1 and SM2. Resynthesis experiments showed that monensin had only a partial inhibitory effect on SM1 resynthesis, and a second sphingomyelinase treatment demonstrated that the resynthesized fraction reached the outer leaflet of the plasma membrane. The 60–70% inhibition of SM synthesis by monensin showed that the trans-Golgi cisternae and the trans-Golgi network are the most likely sites of bulk SM synthesis, and that about 15% of SM was synthesized in the cis/medial Golgi apparatus. Additionally the results indicated that plasma membrane SM synthase activity could be the site of about 15% of SM synthesis in Sertoli cells.     

Bacteriorhodopsin folds into the membrane against an external force

Despite their crucial importance for cellular function, little is known about the folding mechanisms of membrane proteins. Recently details of the folding energy landscape were elucidated by atomic force microscope (AFM)-based single molecule force spectroscopy. Upon unfolding and extraction of individual membrane proteins energy barriers in structural elements such as loops and helices were mapped and quantified with the precision of a few amino acids. Here we report on the next logical step: controlled refolding of single proteins into the membrane. First individual bacteriorhodopsin monomers were partially unfolded and extracted from the purple membrane by pulling at the C-terminal end with an AFM tip. Then by gradually lowering the tip, the protein was allowed to refold into the membrane while the folding force was recorded. We discovered that upon refolding certain helices are pulled into the membrane against a sizable external force of several tens of picoNewton. From the mechanical work, which the helix performs on the AFM cantilever, we derive an upper limit for the Gibbs free folding energy. Subsequent unfolding allowed us to analyze the pattern of unfolding barriers and corroborate that the protein had refolded into the native state.     

Vesicle trafficking: pleasure and pain from SM genes

Most cells contain a variety of transport vesicles traveling to different destinations. Although many specific transport routes exist, the underlying molecular principles appear to be rather similar and conserved in evolution. It has become evident that formation of protein complexes named SNARE complexes between vesicle and target membrane is a central aspect of the final fusion reaction in many, if not all, routes and that SNARE complexes in different routes and species form in a similar manner. It is also evident that a second gene family, the Sec1/Munc18 genes (SM genes), plays a prominent role in vesicle trafficking. But, in contrast to the consensus and clarity about SNARE proteins, recent data on SM proteins in different systems produce an uncomfortable heterogeneity of ideas about their exact role, their site of action and their relation to SNARE proteins. This review examines whether a universal principle for the molecular function of SM genes exists and whether the divergence in SM gene function can be related to the unique characteristics of different transport routes.