Garfish olfactory nerve: easily accessible source of numerous long, homogeneous, nonmyelinated axons

The olfactory nerve of the garfish, Lepisosteus, is about 1 millimeter in diameter and about 20 centimeters long, depending on the size of the fish; it is easily prepared by breaking off successive scored segments of the rostrum. It consists of a relatively homogeneous population of about 10(7) nonmyelineated nerve fibers, each about 0.24 micrometer in diameter. In most other nerves each fiber is separated from all others by an enfolding Schwann cell, but in the olfactory nerve the fibers are directly in contact with one another in groups of several hundred fibers. The Schwann cell, not directly concerned with propagation of the nerve impulse, forms a thin layer at the periphery of the group and makes up a small proportion of the total cellular material. The volume of axon cytoplasm is about five times greater than that of Schwann cell cytoplasm, and the axon surface is about 30 times the Schwann cell surface. The ratio of surface to volume for axons of a typical olfactory nerve is about 5400 times that for the squid axon of the same diameter. The large proportion of axonal membrane recommends this nerve for use in chemical and physical studies of properties of axon membranes.     

Structure of the giant fibers of earthworms

The median giant fiber and the pair of lateral giant fibers that run the length of the ventral nerve cord in earthworms were thought to arise by fusion of the axons of several nerve cells in each segment. The structure of these giant fibers has now been examined with a fluorescent dye injected into single fibers. Each giant axon connects to one cell body in each segment; the giant fibers are not fused axons. In each segment, the median giant fiber has three branches and each lateral giant fiber has five branches. These branches are presumably dendritic. No structural differences between the giant fibers in anterior and posterior regions of the worm seem to account for the functional polarity of the giant fiber system observed in behavioral studies.     

Mechanism of Supercontraction in a Striated Muscle Fiber

Cross-striated muscle fibers may contract reversibly to less than 30 percent of their rest length and it is not easy to reconcile this fact with the sliding filament model of muscular contraction. The mechanism of supercontraction has been studied in fibrils obtained from the giant muscle fibers of the barnacle Balanus nubilus. They were examined by phase-contrast light microscopy and electron microscopy. Contraction beyond the 50-percent stage was found to be achieved largely by the passage of thick filaments through the Z-disks, which are perforated. The overlap of thick filaments from adjacent sarcomeres causes the appearance of the contraction bands about the Z-disks. Subsequent contraction is associated with a folding and loose coiling, but not a shortening, of the thick filaments.     

Reinnervated eye muscles do not respond to impulses in foreign nerves

Normal movements return to carp eyes after section and regeneration of the IIIrd and IVth nerve trunks. Two months after reinnervation, records of impulses in the inferior oblique nerve during tilting of the body show activity of the normal motoneurons to that muscle, together with discharge patterns characteristic of the antagonistic superior oblique and some of the rectus muscles. These axons must have found their way into the inferior oblique trunk during sprouting at the lesion and must be maintained after reinnervation. Impulses from foreign axons are without detectable effect on eye movement and therefore must be blocked at their termination in the muscle. Previous study of cross-innervated and doubly innervated fish eye muscles revealed only structurally normal neuromuscular junctions. Transmission from foreign junctions in multiply innervated muscle is blocked by competitive molecular recognition and control mechanisms that do not cause degeneration.     

Color changes, unusual melanosomes, and a new pigment from leaf frogs

Melanosomes of phyllomedusid frogs are unusually large and are composed of an amorphous matrix of thick fibers. Their hitherto undescribed dark red pigment is neither phaeomelanin nor eumelanin, but seems to be related to melanins. Melanophores of at least one of these species, Agalychnis dacnicolor, exhibit color change in direct response to illumination, and it is suggested that these chromatophores are innervated.     

丽江县玉米螟种类及主要生物学特性研究

 玉米螟普遍发生严重危害玉米。1988年至1990年,作者对丽江县玉米螟种类及其生物学特性进行了调查研究,结果表明,主要种类为亚洲玉米螟(Qstrinia furnacalis)和丽江麻螟新亚种(Qstrinia zealis lijiangensis ssp. ncv.)后者的寄主植物除大麻外,还危害玉米。是我省首次报导危害玉米的新亚种及国内分布新记录。该种雄虫中足胫节增厚具有深槽和与胫节等长的毛撮,雄虫外生殖器抱器腹具刺区显著短于无刺区,端刺有密集组。两种玉米螟每年发生一代。玉米被害株率为8.3%～34.4%;大麻为46%～94%。本文对丽江麻螟新亚种主要外部形态特征作了描述并撰写了两种玉米螟的生物学特性。     

Acetylcholine sensitivity of muscle fiber membranes: mechanism of regulation by motoneurons

Inhibitors of RNA and protein synthesis prevent the development of acetylcholine supersensitivity in organ-cultured rat diaphragm muscle but do not affect established acetylcholine sensitivity. The restriction of this sensitivity in innervated muscle apparently involves muscle fibers.     

猪肌肉肌纤维特性与肌肉品质的关系及品种、性别差异

【目的】研究猪肌肉肌纤维特性与肌肉品质的关系及品种、性别差异。【方法】国内外相关文献的收集、汇总及分析。【结果】①肌纤维的形成是一个非常复杂的生物学过程,肌纤维数目、大小及类型是肌纤维的基本特性。②肌纤维类型的划分,目前最常用的是根据肌纤维中MyHC基因的多态性表达对肌纤维进行分类。③出生前,MyHC异构体按照胚胎期→胎儿期→成熟期顺序表达,出生后,肌纤维类型具有相互转化的特性。④不同类型肌纤维由于代谢特征存在明显差异,因此会影响肌肉色泽、pH、系水力等肌肉品质性状。肌纤维大小、密度与肌纤维类型密切相关,因此也会影响肌肉品质。⑤不同品种猪肌纤维特性有明显差异,因而表现出不同的肌肉品质。为了适应各自生长发育及生理需要,猪不同性别间肌纤维特性也有所不同。【结论】猪肌肉肌纤维特性直接影响肌肉品质的优劣,品种、性别不同,肌纤维特性的形成有一定差异,表现出不同的肌肉品质。     

Spreading of liquids on highly curved surfaces

Because of surface tension, liquid films coating fibers or the insides of capillary tubes are usually unstable and break up into a periodic array of droplets. However, if these films are very thin (of thickness in the range of tens of angstroms), they can be stabilized by long-range van der Waals forces. A simple method for making such wetting films consists of slowly drawing the fiber out of a bath of liquid; the thickness of the film is then measured using a method based on gas chromatography. If these liquid films are thick, and are forced to flow, they may then not break up: the instability becomes "saturated."     

烟叶物理特性与打叶质量的关系

通过描述性统计、逐步回归、偏相关和通径分析,研究了烟叶物理特性与打叶质量指标间的关系。结果表明:大中片率(≥12.7 mm)和≥6.35 mm叶片率在不同品种等级地区间无明显区别;碎片率(3.18~6.35 mm)、碎末率(<3.18mm)、粗梗率和叶中含梗率差异明显;烟叶物理指标与大片率、中片率、粗梗率间达到极显著水平,与小片率达到近似显著水平,其余片烟结构规格与物理指标之间无明显关系。随着烟叶拉力增大,中片率、小片率增加,大片率、粗梗率降低;随着叶片长度和宽度增大,粗梗率降低。     

Length-force relation of calcium activated muscle fibers

Calcium activated skinned frog muscle fibers develop a large relative force at a sarcomere length of 1.0 micrometer. Since the normal myofilament lattice is perturbed at this length, regularity of the lattice does not appear to be an important factor in the contraction mechanism.     

Glycerinated muscle fibers: relation between isometric tension and adenosine triphosphate hydrolysis

The isometric tension of glycerinated muscle fibers and the adenosine triphosphatase activity of homogenates were determined as a function of the concentration of adenosine triphosphate without the addition of divalent cations. These two phenomena are not parallel; large tensions can be developed with negligible hydrolysis of adenosine triphosphate. It is concluded that the large negative free energy change of the hydrolysis is not required for shortening or development of tension.     

基于局部附网法的南极磷虾拖网网身大网目选择性

了解南极磷虾(Euphausia superba)拖网网身大网目的选择性，对于提升应用渔业数据进行磷虾资源评估的准确性具有实际意义。为此，作者在FAO 48.1亚区执行项目调查期间，利用小网目(2a=5 mm)附网绑缚在“龙腾轮”所用拖网的第一段网身(400 mm网目，无内衬网)后端和第二段网身(200 mm网目，内衬网16 mm)前端，收集穿过网目的磷虾。根据附网内取样磷虾的体长分布，结合网囊内取样磷虾的体长分布等数据，选用logistic曲线方程，分析磷虾拖网大网目的选择性。结果表明：（1）“龙腾”轮拖网的磷虾逃逸主要发生在第一段网身大网目处，装配内衬网(2a=16 mm)的第二段网身近乎无逃逸发生。（2）磷虾接触网身第一段大网目的概率(Pc)范围为5.85~69.52%，平均为(23.17±14.80)%。昼夜间接触概率相似，统计学上无显著差异(P>0.05)。50%选择体长(L50)为25.05~47.74 (32.68±4.92) mm；L50在白天(30.06±2.23) mm显著(P<0.05)低于夜间(35.81±5.48) mm。选择范围(SR)为2.07~19.08 (7.65±4.02) mm；SR在白天(7.11±4.41) mm略低于夜间(8.30±3.53) mm，但是在统计学上无显著差异(P>0.05)。本研究结果弥补了拖网整体选择性中网身部位选择性研究的空白，并考虑了昼夜间磷虾选择性的差异，可为科学评估磷虾资源量和开发生态友好型磷虾拖网提供科学依据。     

穴居狼蛛生活习性之初步观察

穴居狼蛛(Lycosa singoriensis)雌蛛平均体长31.9 mm,头胸长15.1 mm,腹长17.2 mm,体重4.2 g.头胸部梨形,前部隆起,中间有黑、褐、白相间的辐射状斑,两侧被灰黄色毛,腹部椭圆形,背面密布黑色小斑点,中间有黑褐色心斑,并有6对黄白色肌斑,胸板和腹部腹面密生黑色毛.雄蛛平均体长26.8 mm,头胸长14.6 mm,腹长12.9 mm,体重2.6 g,形状与雌蛛相似,但体色较浅,腹部明显较小.新疆已知分布于32个县市.生活在草原、森林、荒漠、农田、果园、山坡等地,筑穴而居,洞口圆形或椭圆形,平均直径2.65 cm,洞深31.6 cm.白天多在洞中隐伏,傍晚或夜间在洞口附近猎食,用直接袭击法捕食各类昆虫.雄成蛛一般不筑洞穴,游猎生活,主动寻找洞穴中雌蛛在洞内或将其引出洞外交配.交配可分3个阶段,即:雄蛛求婚、雌雄交配、雄蛛离开,历时1～1.5 h,但实际交配时间仅10～30 min.未发现雌蛛在交配后残杀雄蛛的事例.雌蛛于4～7月织卵袋产卵,卵袋椭圆形,灰白色,由两片组成,平均体积20.0×16.8×14.3(mm)3,每袋平均含卵466.3粒.卵自产出之日起至发育成若蛛并走出卵袋,平均需21 d.若蛛出袋后,先群聚于雌蛛腹背上,随雌蛛出外活动,有时下到地面吸水或采食雌蛛食剩的虫体或残屑,平均经11.8 d离开母体独立生活.雌若蛛经6～7次蜕皮成熟,10月下旬至次年3月上旬为越冬期,若蛛或成蛛将洞口用丝网封闭蛰伏在洞内越冬.雌蛛平均寿命2年,雄蛛1年左右.     

黄淮白山羊舌黏膜组织结构及神经纤维分布研究

[目的]运用组织学方法对黄淮白山羊舌黏膜组织结构及神经纤维分布进行观察。[方法]选用健康黄淮白山羊3只,通过颈动脉放血致死,立即取其舌尖、舌体、舌根、舌圆枕各部组织,经4%多聚甲醛溶液固定24 h后脱水、包埋、切片、HE及银氨染液染色后显微镜观察。[结果]舌黏膜主要包括黏膜层、黏膜下层和舌肌,在光镜下各层分界明显,黏膜上皮为复层扁平上皮细胞,舌尖部黏膜层上皮组织相对较薄,黏膜层中可见明显的味蕾,舌尖处神经纤维主要分布于黏膜表面相邻乳头之间的凹陷处,舌乳头黏膜层较少观察到神经纤维;舌体和舌圆枕黏膜层较厚,可观察到较多的乳头突入黏膜层,舌根黏膜层最薄,突入到黏膜层的乳头结构少。舌体和舌根处的黏膜层可观察到较多平行排列的神经纤维。[结论]黄淮白山羊舌尖部黏膜层最薄,舌体和舌根处最厚,舌尖和舌体及舌根部肌纤维为骨骼肌。神经纤维主要分布于黄淮白山羊舌黏膜层。     

Hormonal control of the anatomical specificity of motoneuron-to-muscle innervation in rats

Motoneurons of the spinal nucleus of the bulbocavernosus innervate bulbocavernosus muscles in male rats. Adult female rats normally lack both the spinal nucleus and its target muscles. Prenatal treatment of females with testosterone propionate resulted in adults having, like males, both the spinal nucleus and its target muscles. However, prenatal treatment with dihydrotestosterone propionate preserves the muscles but not the motoneurons. This paradoxical condition might result from (i) bulbocavernosus muscles without innervation; (ii) muscles innervated by morphologically unrecognizable motoneurons; (iii) muscles innervated by a very few spinal nucleus cells, each innervating many bulbocavernosus fibers; or (iv) muscles innervated by motoneurons outside their normal anatomical locus in the spinal nucleus. The results of retrograde marker injections into the bulbocavernosus muscles of females treated with androgen refute the first three possibilities and confirm the last: the different androgen treatments result in anatomically distinct spinal motor nuclei innervating bulbocavernosus muscles.     

PRSS35在鸡卵泡膜细胞中的表达与卵泡液雌激素含量的关系

旨在研究PRSS35在鸡卵泡中的表达部位及在不同大小等级前卵泡内膜细胞中的表达模式与雌激素分泌的关系。选取直径为1～2 mm的小白卵泡、3～5 mm的大白卵泡、6～8 mm的小黄卵泡和9～12 mm的大黄卵泡,应用免疫组织化学技术对PRSS35在大白卵泡和小黄卵泡中的表达进行组织定位;分别抽取4种卵泡的卵泡液,并通过ELISA法测定各卵泡液中的雌激素(E_2)含量;刮取卵泡内膜细胞,分别利用QRT-PCR和Western blot技术检测 PRSS35 mRNA和蛋白在蛋鸡不同大小等级前卵泡内膜细胞中的表达情况。结果显示,PRSS35在蛋鸡卵泡颗粒细胞层、膜细胞层和卵丘细胞均有表达; PRSS35mRNA和蛋白在小黄卵泡中的含量均显著高于其他卵泡;E_2在小黄卵泡卵泡液中的含量显著高于其他卵泡,在小白卵泡和大白卵泡卵泡液中显著高于大黄卵泡。推测PRSS35在小黄卵泡中可能会促进卵泡内膜细胞分泌E_2,从而影响卵泡的选择。     

Multiple temperature-sensitive spots innervated by single nerve fibers

Electrophysiological recordings were made from single nerve fibers which were specifically responsive to temperature changes of the skin of monkeys. Previous reports indicated that the receptive area on the skin of such preparations was a single small spot less than 1 millimeter in diameter. However, we found that the activity in a single thermally sensitive fiber increased when any one of eight individual spots on the skin was cooled. In other preparations two to six spots, each less than 1 millimeter in diameter, appeared to be innervated by a single fiber. The neural activity resulting from the cooling of one or several of these spots summed, and we suggest that this summation may be the neural analog of areal summation of thermal stimuli reported in psychophysical measurements.     

双峰驼骨骼肌的组织与超微结构观察

在光镜及电镜下,双峰驼骨骼肌的肌外膜与肌束膜均较厚,其中除有不等的胶原纤维、弹性纤维、网状纤维、成纤维细胞及血管、神经外,还有丰富的脂肪细胞。在肌纤维外有薄层肌纤维膜,后者与肌内膜相连。骨骼肌肌纤维一般较粗,但其粗细差异很大（长约4～55mm,宽约9～125μm）,呈长短不一的圆柱状、A带、I带相间的横纹明显。肌原纤维也较粗大（直径约7～14nm,长约15～2．5μm）。肌原纤维间的肌浆中响大量线粒体及糖原颗粒。线粒体体积大,嵴较长,呈典型的板层状。     

福建红黄壤主要粘粒矿物的形态特征

在 X 射线衍射鉴定的基础上,用透射电镜对福建红黄壤中常见的粘粒矿物的形态特征进行了观察,高岭石呈假六方片状和次圆形片状,大小差异较大,埃洛石呈管状。颗粒大的伊利石呈三角片状或棱角分明的长方片状,有的伊利石呈板条状,次生绿泥石矿物的形态与伊利石相近,呈不同形态的片状,赤铁矿主要以豆状及肾状存在,颗粒较小。针铁矿呈针状或小纺锤状。三水铝石多为小的豆状,鳞片状,有时也呈大的板状。