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1.
R Bodmer  S Barbel  S Sheperd  J W Jack  L Y Jan  Y N Jan 《Cell》1987,51(2):293-307
The identities of two types of sensory organs in the body wall of Drosophila, namely the external sensory organs and the chordotonal organs, are under genetic control. Embryonic lethal mutations in the cut gene complex transform the external sensory organs into chordotonal organs. The neurons, as well as the support cells forming the external sensory structures, change their morphological and antigenic characteristics to those of chordotonal organs, providing genetic evidence that these two types of sensory organs are homologous. Similar transformations of external sensory organs are observed in adult mosaic flies. Analysis of mosaic larvae and flies suggests that the cut gene function is required either in or near external sensory organs in order for them to acquire their correct identity.  相似文献   

2.
Kjeld  Hansen  Peter J.  Herring 《Journal of Zoology》1977,182(1):103-124
Females of the anglerfish genus Linophryne bear barbels containing luminous organs, in addition to an escal light organ. Luminescence has been observed from the barbels of four species of Linophryne , and the morphology of the luminous organs investigated. The barbel light organs do not contain bacteria but complex paracrystalline photogenic granules. The esca contains luminous bacteria. The esca is ectodermal in origin whereas the barbel organs may be derived from the mesoderm.
The possible significance of this unique dual system of luminous organs is discussed.  相似文献   

3.
Light and electron microscopic observations of the lateral-line organs of larval Ichthyophis kohtaoensis confirmed earlier reports of the occurrence of two different types of lateral-line organs. One type, the ampullary organ, possesses 15–26 egg-shaped sensory cells. Each sensory cell extends a single kinocilium surrounded by a few microvilli into the ampullary lumen. This is in contrast to the ampullary organs of urodele amphibians that contain only microvilli. The second type of organ, the ordinary neuromast, has 15–24 pear-shaped sensory cells arranged in two to three rows. Each sensory cell shows a kinocilium that is asymmetrically placed with respect to both a basal plate and approximately 60 stereovilli. The sensory cells of ampullary organs are always separated by supporting cells; those of neuromasts are occasionally in contact with one another. Numerous (neuromasts) or few (ampullary organs) mantle cells separate the organs from the epidermal cells. Only afferent synapses are found in the ampullary organs whereas vesicle-filled fibers together with afferent nerve terminals are found in neuromasts. Both organs contain similarly sized presynaptic spheres adjacent to the afferent fibers. It is suggested that the neuromasts have a mechanoreceptive function, whereas the ampullary organs have an electroreceptive one.  相似文献   

4.
A Sudo 《Life sciences》1987,41(22):2477-2484
In order to examine the origin and location of adrenaline in peripheral organs of mammals, adrenaline and noradrenaline were measured in several organs of the rat after adrenalectomy, guanethidine treatment and imipramine injection. One week after bilateral adrenalectomy, adrenaline disappeared almost completely from the heart, spleen and submaxillary gland. Chronic administration of guanethidine caused decreases in both noradrenaline and adrenaline in the peripheral organs. Injection of imipramine induced a reduction of adrenaline concentration in the spleen and submaxillary gland. It is considered that adrenaline in the peripheral organs of mammals is mostly derived from the adrenal gland and that circulating adrenaline is taken up by sympathetic nerve endings in the organs. The adrenaline content of the peripheral organs increased after electric foot-shock and changed according to the time of day. The peak of the circadian rhythm appeared about 6 hours after the peak of the urinary adrenaline rhythm. These findings suggest that adrenaline in body organs plays some role in the responses of the sympathetic nervous system to stressful conditions or even to daily activities.  相似文献   

5.
The scanning electron microscope (SEM) has been used to study the morphology of the accessory air-breathing organs of the catfish Clarias batrachus . Although the gross morphology of the dendritic organs, the fan organs and the membrane lining the supra-branchial chambers differ, the nature of the respiratory surfaces are similar. The gaseous exchange surfaces of all three organs consist of double rows of paired lamellae, a feature strongly indicative of their common origin from the gills. The surfaces of the epithelial cells from the respiratory organs were seen to have numerous small projections consisting of microvilli and short microridges. This is in contrast to the concentric whorls of micro-ridges on the surface of cells from the interlamella regions of these organs.  相似文献   

6.
中国大鲵侧线器官的研究   总被引:1,自引:0,他引:1  
程红  黄世强 《动物学报》1995,41(3):235-242
本文以光镜和扫描是镜手段研究了中国大鲵幼体,亚成体及成体头部及躯干部表皮中的侧线器官,即电接受壶腹器官,机械接受的表面神经丘和陷器官的分布,形态和发展变化。壶腹器管仅存于幼体头部,变态结束后消失,后两种终生存在,但前者按一定路线和方向排列,后者仅存于头部,陷在表皮中,文章探讨了壶腹器官的原始性,其消失与生活习性以及由水登陆进化的关系;对三种器官的形态及其它有尾类的侧线器官进行了比较。  相似文献   

7.
Scanning and transmission electron microscopy (SEM and TEM) were used to study lattice organs in facetotectan y‐cyprids from the White Sea and from Norwegian and Bahamian waters. The larvae represent at least four and possibly five different species of Facetotecta. Y‐cyprids have five pairs of lattice organs in the head shield (carapace) organized into two anterior pairs and three posterior pairs. Both groups of lattice organs are arranged around a large central pore. The facetotectan lattice organs are elongate areas with a longitudinal keel, just as in the Ascothoracida and some Cirripedia Acrothoracica. The terminal pore of the organs is situated posteriorly in all five pairs. TEM confirms that the organs have the same general morphology as in the Cirripedia and Ascothoracida, namely, a cuticular chamber into which project ciliary segments from the chemosensory cells. Unlike Cirripedia the cuticular roof of the chamber lacks any pores. We conclude that five pairs of lattice organs represent an autapomorphy for the Thecostraca, which supports the monophyly of this taxon. In the ground pattern the terminal pore is posterior in all five pairs. The anterior position of the pore in lattice organ pair 2 is apomorphic for the Cirripedia, while within this taxon an anterior position also in pair 1 is apomorphic for a monophylum comprising the Thoracica and the Rhizocephala. Minute pores in the roof of the organs is another apomorphy of the Cirripedia, but its elaboration into pores visible with SEM may have been subject to some homoplasy. Since lattice organs are omnipresent in the settling instar of the Thecostraca they probably serve a critical role for the function of these cypris or cypris‐like larvae.  相似文献   

8.
BACKGROUND AND AIMS: Neoformation is the process by which organs not preformed in a bud are developed on a growing shoot, generally after preformation extension. The study of neoformation in trees has been hindered due to methodological reasons. The present report is aimed at assessing the relative importance of preformation and neoformation in the development of shoots of woody species. METHODS: A deconvolution method was applied to estimate the distribution of the number of neoformed organs for eight data sets corresponding to four Nothofagus species and a Juglans hybrid. KEY RESULTS: The number of preformed organs was higher and less variable than the number of neoformed organs. Neoformation contributed more than preformation to explain full-size differences between shoots developed in different positions within the architecture of each tree species. CONCLUSIONS: Differences between the distributions of the numbers of preformed and neoformed organs may be explained by alluding to the duration of differentiation and extension for each of these groups of organs. The deconvolution of distributions is a useful tool for the analysis of neoformation and shoot structure in trees.  相似文献   

9.
I. Hasenfuss 《Zoomorphology》1997,117(3):155-164
 The patterns of scolopal organs and their innervation were studied by the methylene blue method in larvae, pupae and adults of an Yponomeuta species (Yponomeutidae) and of tympanate adult representatives of the Noctuoidea, Geometridae, Drepanidae and Pyraloidea. The studies were focused mainly on the mesothorax, the metathorax and some anterior abdominal segments. In the abdominal tympanal organs of Geometridae, Drepanidae and Pyraloidea, the auditory scolopidia are homologous with the lateral scolopal organs of the first abdominal segment; however, the hearing organs as such evolved independently in the three taxa. The studies confirm that the tympanal organ in the Noctuoidea is derived from the caudal dorsolateral region of the metathorax including its dorsal scolopal organ and the B-cell. The adult scolopal organs are present already in the larvae and are maintained nearly unchanged during metamorphosis to the adult. Only in the Noctuoidea are the three sensory cells of the larval scolopal organs, which become part of the tympanal organs, reduced to one (in Notodontidae) or two (in other Noctuoidea) during metamorphosis. A hypothetical scenario of the evolution of the tympanal organs is outlined. Accepted: 12 March 1997  相似文献   

10.
The distribution of pit organs (free neuromasts) has previously been documented for several species of pelagic sharks, but is relatively poorly known for rays and bottom-dwelling (demersal) sharks. In the present study, the complete distribution of pit organs was mapped in the demersal sharks Heterodontus portusjacksoni, Orectolobus maculatus, Hemiscyllium ocellatum, Chiloscyllium punctatum, and Asymbolus analis, and the rays Rhinobatos typus, Aptychotrema rostrata, Trygonorrhina sp. A, Raja sp. A, and Myliobatis australis. All of these species had pit organs scattered over the dorsolateral surface. The sharks also had "mandibular" pit organs (and "umbilical" pit organs in C. punctatum and A. analis) on the ventral surface, while pit organs were sparse or absent on the ventral surface of rays. All of the species examined here, except for M. australis, also had a "spiracular" group of pit organs adjacent to the eye and/or spiracle. Spiracular pit organs were also recorded for the sawshark Pristiophorus sp. A and the skate Pavoraja nitida, although the remainder of pit organs were not mapped in these species. The distribution and number of pit organs varied both within and among species. Pit organ distribution was asymmetrical in each individual examined, but no particular trend towards left or right "handedness" was observed in any species. Although rays have been thought to have fewer pit organs than sharks in general, this was not the case in the present study. All of the species examined here had few pit organs compared to the pelagic sharks previously documented, but it is not clear whether this is due to ecological or phylogenetic causes.  相似文献   

11.
The concepts of photosynthesis role in the production process underwent evolution from the initial assumption of complete identity of these terms to the notion that photosynthesis is only a supplier of assimilates for sink organs. The following issues are discussed as individual stages of problem resolution: whether or not photosynthesis restricts productivity; what is the contribution of chlorophyll-containing non-leaf organs to the production process; what are the roles of photooxidation processes and source-sink relations between photosynthesizing organs and assimilate consumers; how the apoplast is involved in regulation of photosynthetic function of the whole plant; and what is the role of nitrate in control of photosynthesis and assimilate export from the leaf. Finally, the distribution of assimilates among the sink organs and the role of competition among the organs in regulation of photosynthesis and yield formation are considered.  相似文献   

12.
王珊  那宇鹤  冷雪  那杰 《昆虫知识》2010,47(4):652-656
昆虫的听器是一类对声波具有特异感受作用的器官,对其生存具有非常重要的意义。昆虫的听器主要有听觉毛、江氏器和鼓膜听器3种类型。本文主要介绍了昆虫3种听器的结构和功能特点,并从系统发生和个体发育角度介绍了鼓膜听器的演化过程。  相似文献   

13.
Scolopidial sensilla in insects often form large sensory organs involved in proprioception or exteroception. Here the knowledge on Nebenorgans and accessory organs, two organs consisting of scolopidial sensory cells, is summarised. These organs are present in some insects which are model organisms for the physiology of mechanosensory systems (cockroaches and tettigoniids). Recent comparative studies documented the accessory organ in several taxa of Orthoptera (including tettigoniids, cave crickets, Jerusalem crickets) and the Nebenorgan in related insects (Mantophasmatodea). The accessory organ or Nebenorgan is usually a small organ of 8–15 sensilla located in the posterior leg tibia of all leg pairs. The physiological properties of the accessory organs and Nebenorgans are so far largely unknown. Taking together neuroanatomical and electrophysiological data from disparate taxa, there is considerable evidence that the accessory organ and Nebenorgan are vibrosensitive. They thus complement the larger vibrosensitive subgenual organ in the tibia. This review summarises the comparative studies of these sensory organs, in particular the arguments and criteria for the homology of the accessory organ and Nebenorgan among orthopteroid insects. Different scenarios of repeated evolutionary origins or losses of these sensory organs are discussed. Neuroanatomy allows to distinguish individual sensory organs for analysis of sensory physiology, and to infer scenarios of sensory evolution.  相似文献   

14.
在体外制造可修复人体受损组织与器官功能的活性替代物一直是人类的梦想.制造、材料与生命科学的交叉与融合发展,为生物组织与器官的体外制造提供了必要的技术、材料与生物学基础,从而实现了皮肤、骨、膀胱等简单活性组织的临床应用,但人体重要实质器官如肝脏、肺等的再造研究至今未取得突破性进展.重要实质器官内部复杂的微观结构系统及多细胞体系的构建是实现其体外制造的关键,也是当前生物组织与器官制造技术所面临的巨大挑战.从生物制造的角度,综述国内外在重要实质器官复杂微结构制造领域的主要技术方法及最新研究进展,通过分析与评价,对未来重要实质器官的生物制造技术发展进行展望.  相似文献   

15.
棉花体细胞培养再生植株存在大量的生理变异和可遗传变异,从中分离到一个性状稳定的花器变异体(CHV1)。从花器官形态特征和表面显微特征分析,该变异体的所有花器官都变成了苞叶状器官,但中央数片叶状器官的基部有胎座和胚珠着生。变异体每朵花有苞叶3—7片,苞叶状器官19—41片。苞叶状器官在花梗上的排布介于“轮”与“螺旋”状之间。据花器发育理论和变异体花的生长特性推测,该变异体中控制花器发育的A、B和C功能皆失活。对造成该变异的可能机理和棉花花发育模式进行了分析。该变异材料对研究棉花花发育和体细胞无性系变异的机理有一定价值。  相似文献   

16.
Osaki  M.  Shinano  T.  Yamada  M.  Yamada  S. 《Photosynthetica》2004,42(1):123-131
Leaf-root interaction is a critical factor for plant growth during maturation and activity of roots is maintained by a sufficient supply of photosynthates. To explain photosynthate distribution among organs in field crops, the node unit hypothesis is proposed. One node unit consists of a leaf and an upper adventitous root, as well as the axillary organs and the lower adventitious root, which is adjacent to one node. Using 14C as tracer, the carbon distribution system has been clarified using spring wheat, soybean, tomato, and potato. The interrelationship among organs from the strongest to the weakest is in the following order: (1) within the node unit > (2) between the node unit in the same or adjacent phyllotaxy > (3) in the main root or apical organs, which are adjacent to the node unit. Within the node unit, 14C assimilated in the leaf on the main stem tended to distribute to axillary organs in the same node unit. The 14C assimilated in the leaf of axillary organs tended to distribute within the axillary organs, including adventitious roots in the axillary organ and then translocated to the leaf on the main leaf of the same node unit. In different organs of the node unit in the same or adjacent phyllotaxy, 14C assimilated in the leaf on the main stem was also distributed to the organs (node unit) belonging to the same phyllotaxy in dicotyledons, while in monocotyledons, the effect of phyllotaxy on 14C distribution was not clear. Among roots/apical organs and node unit, 14C assimilated in the upper node unit was distributed to apical organs and 14C assimilated in the lower node unit was distributed to roots. Thus the node unit hypothesis of photosynthate distribution among organs is very important for understanding the high productivity of field crops.  相似文献   

17.
ABSTRACT. The contributions of olfactory and gustatory organs in food plant discrimination were examined in larvae of Manduca sexta (Johan.) (Lepidoptera, Sphingidae). Larvae, from which various chemosensory organs had been removed surgically, were tested for feeding preferences for a host, tomato ( Lycopersicon esculentum ); a weakly acceptable non-host, rape ( Brassica napus ); and an unacceptable non-host canna ( Canna generalis ), using a two-choice disc bioassay.
Removal of all known chemosensory organs resulted in failure to show discriminatory behaviour in a strictly chemosensory bioassay, indicating that all external chemosensory organs have been accounted for. The involvement of non-chemosensory organs results in residual discrimination for leaves by individuals with total chemosensory ablations.
Larvae possessing either olfactory or gustatory organs still exhibit normal preferences for tomato over rape. Gustatory (but not olfactory) organs are required for larvae to show normal preferences for tomato over canna; in fact, olfactory organs do not appear to participate in this decision.
To examine which if any of the plant species is being selected in two-choice tests, larvae were given a choice between each leaf species and a 'neutral' substance (wet filter paper). Both olfactory and gustatory organs are required for normal preferences for tomato, but either alone will suffice for rape. Only gustation is needed to select canna, and participation of either the epipharyngeal sensilla or a single medial sensillum styloconicum is sufficient to elicit complete rejection behaviour.
We conclude that, in larvae of M. sexta , the complement of chemosensory organs needed for food plant discrimination varies with the plant species sampled. Evidence is presented exposing a potential artefact of ablation experiments; extirpation of one sensory organ may affect the functioning of others nearby, even though they may appear normal by visual inspection.  相似文献   

18.
The histomorphology of the retrocerebral endocrine organs of the larva of the lemon-butterfly, P. demoleus has been described employing a conventional neurosecretory staining technique. The larval organs lie a little away from the brain and oesophagus and, therefore, are not sub-aortic in position unlike most other insects and the adult of this species itself. There are two long NCCs which innervate other target organs in addition to the CC. The recurrent nerve of the stomatogastric nervous system retains its normal connections with the CC even in absence of the hypocerebral ganglion. Histological evidence suggests that the NSM inside the CC remains intraaxonal without being possibly unloaded in the substance of these organs. Axonal transport of NSM to target organs is also in evidence and though NSM is seen in the NCA, it could not be detected inside the CA.  相似文献   

19.
Each side of the abdominal segments of the stick insect Carausius morosus contains a chordotonal organ lying longitudinally in a ventro-lateral position. These ventro-lateral chordotonal organs each possess two nerve cell bodies and two scolopales. There is a single attachment strand to the cuticle.Electrical recordings from the receptors show that they respond in a highly phasic manner to both stretching and subsequent relaxation of the attachment strand. They are sensitive to substrate vibration but are activated by ventilatory movements. The effects of ramp and square wave stimulation are examined. The rôle of the ventro-lateral chordotonal organs as ventilatory receptors is discussed and abdominal chordotonal organs of insects in general are reviewed.The ‘ventral phasic receptors’ of the cockroach are re-examined and shown to be chordotonal organs. They are re-named ‘mid-ventral’ chordotonal organs.  相似文献   

20.
The homeotic genes are instrumental in establishing segment-specific characteristics. In Drosophila embryos there is ample evidence that the homeotic genes are involved in establishing the differences in the pattern of sense organs between segments. The chordotonal organs are compound sense organs made up of several stretch receptive sensilla. A set of serially homologous chordotonal organs, lch3 in the 1st thoracic segment, dch3 in the 2nd and 3rd thoracic segments and lch5 in abdominal segments 1 to 7, is composed of different numbers of sensilla with different positions and orientations. Here we examine this set of sense organs and a companion set, vchA/B and veh1, in the wild type and mutants for Sexcombs reduced, Antennapedia, Ultrabithorax, and abdominal-A, using immunostaining. Mutant phenotypes indicate that Ultrabithorax and abdominal-A in particular influence the formation of these sense organs. Differential expression of abdominal-A and Ultrabithorax within compartments of individual parasegments can precisely modulate the types of sense organs that will arise from a segment.  相似文献   

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