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61.
62.
The attachment ability of insects on surfaces are associated not only with the micro- and nanostructure of the adhering part
of an attachment device, but also with the global scale kinematics responsible for contact formation and release. In the present
study, the locomotory techniques of several representatives of insects from four different orders (Orthoptera, Heteroptera,
Coleoptera, and Hymenoptera), possessing different types of attachment structures, are described. The study is based on video
recordings of insects walking on a flat surface and on cylindrical rods of various thickness, imitating plant stems. Attachment
devices of tarsi and pretarsi were visualized using Scanning Electron Microscopy. The results show a different manner in the
use of adhesive structures on substrates with various curvatures. Insects bearing attachment pads on proximal tarsomeres usually
touch flat and curved substrates using all tarsomeres, whereas insects with their attachment devices on the distal tarsomeres
usually walk on flat surfaces using the distal tarsomeres of the overextended tarsus. On substrates, with diameters comparable
to or larger than the tarsus length, insects walk above the stem by clasping the stem with the bent tarsi. On thin stems,
insects clasp the stem between their tarsi and hang under the stem. Thus, on thin and thick rods, forces applied to attachment
organs act in opposite directions. There are two methods of leg positioning for walking on a rough flat substrate. In the
first case, the tarsus is straightened and the rough substrate is gripped between the claws and the proximal complex of attachment
devices (tarsal euplantulae, fossulae spongiosa, and terminal spurs of tibiae). In the second case the tibia does not touch
the substrate; the insect is supported only by distal tarsomeres. The tarsus is in an overextended condition. On rods, with
diameters comparable to or larger than the tarsus length, insects walk by clasping the stem with the bent tarsi. This posture
is characteristic for the majority of insects independent of the tarsal position they normally use while walking on a plane.
If the rod’s diameter is smaller than the tarsus length, walking insects usually clutch it between contralateral tarsi. Using
such a posture they are supported by interlocking or by strong friction, generated by attachment devices of the proximal tarsomeres,
and do not use attachment devices of the pretarsus. Contact with the substrate is reinforced due to the coordinated contralateral
clutch using all supporting legs. It is concluded that the use of different types of attachment structures correlates with
locomotory techniques.
Handling Editor: Heikki Hokkanen 相似文献
63.
Nilanjana Mazumdar Phil M. Novis Gabriel Visnovsky Peter Gostomski 《Journal of phycology》2019,55(5):1071-1081
The present study investigated the effect of different culture conditions on the vegetative growth of a new species, Haematococcus alpinus (strain LCR‐CC‐261f) using airlift photobioreactors. The influence of culture medium, aeration rates, CO2 concentration in air‐gas mixture, temperature, light intensities, and wavelengths were investigated to achieve sustainable high cell density cultures. Growth parameters were determined by fitting the data to a form of the logistic equation that included a lag phase. The shear‐sensitive vegetative cells favored lower aeration rates in the photobioreactors. MLA medium increased to 40 mM nitrate produced high density cultures. Temperatures between 12°C and 18°C, 3% (v/v) CO2 concentration and a narrow photon flux density ranging between 37 and 48 μmol photons · m?2 · s?1 were best suited for growth. The wavelength of the light source also impacted growth and a high cell density of 9.6 × 105 cells · mL?1 was achieved using a mixture of red and blue compared to warm white, red, or blue LEDs. 相似文献
64.
A comprehensive study of stem, leaf and petiole anatomy of 10 species of Strobilanthes from northern Western Ghats of India was carried out to identify characteristics which would enable species identification when flowering material is unavailable. In Strobilanthes, some species bloom annually, others are plietesials, i.e. they grow without blooming for several years and then produce huge quantities of flowers, release seeds and die. Therefore, alternative methods, such as anatomical characters, are essential to distinguish Strobilanthes species in their vegetative stage. We collected ten species of Strobilanthes for anatomical characterization. Under the bright‐field microscope, stem cross‐sections of different species were found to be undulate, quadrangular, quadrangular‐winged or terete. Study of the stem revealed a distinct outer and inner cortex, the distribution of cystoliths (CaCO3 crystals), raphides (CaC2H2O5 crystals) and sclereids which varied from species to species. Study of leaf anatomy showed structural variation and vascular bundle shapes that differed between the species. Leaf epidermal characters under light and scanning electron microscopy exhibited variation in characters such as stomatal index, stomatal length and width, stomatal type and presence of glandular and non‐glandular trichomes. The petiole anatomy was species‐specific, especially with respect to vascular bundle structure and the distribution of structures such as sclereids, cystoliths, sphaeraphides and tannin cells varied. Hence, unique anatomical features of the stem, leaf and petiole could be used as taxonomic characters to identify Strobilanthes species in a vegetative state. 相似文献
65.
The renal organs of 32 species of cephalopods (renal appendage of all cephalopods, and renal and pancreatic appendages in decapods) were examined for parasite fauna and for histological comparison. Two phylogenetically distant organisms, dicyemid mesozoans and chromidinid ciliates, were found in 20 cephalopod species. Most benthic cephalopods (octopus and cuttlefish) were infected with dicyemids. Two pelagic cephalopod species, Sepioteuthis lessoniana and Todarodes pacificus, also harbored dicyemids. Chromidinid ciliates were found only in decapods (squid and cuttlefish). One dicyemid species was found in branchial heart appendages of Rossia pacifica. Dicyemids and chromidinids occasionally occurred simultaneously in Euprymna morsei, Sepia kobiensis, S. peterseni, and T. pacificus. The small-sized cephalopod species, Idiosepius paradoxus and Octopus parvus, harbored no parasites. Comparative histology revealed that the external surface of renal organs varies morphologically in various cephalopod species. The small-sized cephalopod species have a simple external surface. In contrast, the medium- to large-sized cephalopod species have a complex external surface. In the medium- to large-sized cephalopod species, their juveniles have a simple external surface of the renal organs. The external surface subsequently becomes complicated as they grow. Dicyemids and chromidinids attach their heads to epithelia or insert their heads into folds of renal appendages, pancreatic appendages, and branchial heart appendages. The rugged and convoluted external surface provides a foothold for dicyemids and chromidinids with a conical head. They apparently do not harm these tissues of their host cephalopods. 相似文献
66.
B.?McCarthy A.?Daws D.?L.?MacmillanEmail author 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》2004,190(4):291-299
Recordings were made from the nerve innervating the stretch receptors of the abdominal muscle receptor organs and slow extensor muscles of tethered crayfish, Cherax destructor, during so-called non-giant swimming. The stretch receptors were active during the flexor phase of swimming but the duration and pattern of activity varied from cycle to cycle. Their pattern of firing was modified by the activity of the large accessory neurons which make direct inhibitory synapses upon them. Neither the stretch receptors nor the accessory neurons were active during the extensor phase of the cycle. The timing and extent of tailfan movements during the period of stretch receptor activity were measured from video records before and after the stretch receptor nerves were cut in the second to fifth segments. The promotion of the tailfan during flexion was significantly delayed and the minimum angle to which the uropods were remoted at the end of flexion significantly larger in denervated animals. We propose that afferent information from the stretch receptors coordinates the timing and extent of tailfan movements according to variations in the positioning and movement of the abdominal segments such that the hydrodynamic efficiency of the tailfan is enhanced on a cycle by cycle basis during non-giant swimming.Abbreviations A# abdominal segment number - Acc accessory neuron - LUU large unidentified unit - MRO muscle receptor organ - NGS non-giant swimming - SEMN slow extensor motor neuron - SR stretch receptor neuron 相似文献
67.
对芸香的茎、叶及花等器官的形态结构进行了较为系统的观察研究,对花芽形成及开花过程进行了客观描述.芸香花有顶生和侧生两种,柱头为"湿柱头",叶片具有典型旱生型植物特点,茎叶中均含有簇晶和油腔,这些特征可作为分类学上鉴别该物种的性状.茎的淀粉积累过程:花前期淀粉积累很少(6月下旬),10月下旬达高峰,之后略有减少并保持稳定直至被冻死.对此结合当地温度及水分条件进行了抗寒、抗旱的讨论. 相似文献
68.
Architectural analysis of 840 Slovenian walnut (Juglans regia L.) genotypes was performed to determine the most typical and frequent morphological types and to evaluate their vegetative and generative potential. Four branching and fruiting patterns (I-IV) were detected. A 3-year-old fruiting branch, consisting of a 3-year-old shoot plus corresponding 2-year-old and 1-year-old shoots, was used as a structural unit for quantitative analysis. In the intermediate fruit-bearing types with mesotonic and acrotonic branching pattern (types II and III), the total lengths of 3-, 2- and 1-year-old shoots were 385 and 380 cm, respectively, compared with 275 and 253 cm in the terminal and lateral-fruiting types (types I and IV). In type I, 1-year-old shoots had significantly fewer nodes than in other types. In addition, they had a thinner basal diameter than types III and IV, and their angles were the most erect (39 degrees ). Only 0.4 out of 3.6 1-year-old shoots were flowering with one mixed bud with 1.9 female flowers. In type IV, 2-year-old shoots had significantly more nodes and a larger basal diameter than other types. One-year-old shoots in type IV are thicker than those in other types. Ratios between the number of flowering and the total number of 1-year-old shoots were 0.7 in type IV, 0.6 in type III, 0.5 in type II and 0.1 in type I. On 1-year-old shoots in type IV, 1.7 mixed buds with a mean of three female inflorescences per bud were counted. Consequently, the generative potential is highest in type IV and lowest in type I. In types II and III, growth and the ability to bear fruits are more balanced. 相似文献
69.
Whole body studies of Plotosus tandanus revealed that ampullary pores occur over the entire body of the fish, but are in higher concentrations in the head region. These pores give rise to a short canal (50-60 microm) produced by columnar epithelial cells bound together by tight junctions and desmosomes. At the junction of the canal and the ampulla, cuboidal epithelial cells make up the wall. The ampulla consists of layers of collagen fibers that surround flattened epithelial cells in the lateral regions and give rise to supportive cells that encase a small number of receptor cells (10-15). The ampullary wall comprises several types of cells that are adjoined via tight junctions and desmosomes between cell types. The ovoid receptor cells possess microvilli along the luminar apical area. Beneath this area, the cells are rich in mitochondria and rough endoplasmic reticulum. An unmyelinated neuron adjoins with each receptor cell opposite multiple presynaptic bodies. This form of microampulla has not been previously described within the Family Plotosidae. 相似文献
70.
Li L Kelley WP Billimoria CP Christie AE Pulver SR Sweedler JV Marder E 《Journal of neurochemistry》2003,87(3):642-656
The crustacean stomatogastric ganglion (STG) is modulated by both locally released neuroactive compounds and circulating hormones. This study presents mass spectrometric characterization of the complement of peptide hormones present in one of the major neurosecretory structures, the pericardial organs (POs), and the detection of neurohormones released from the POs. Direct peptide profiling of Cancer borealis PO tissues using matrix-assisted laser desorption/ionization (MALDI) time-of-flight (TOF) mass spectrometry (MS) revealed many previously identified peptides, including proctolin, red pigment concentrating hormone (RPCH), crustacean cardioactive peptide (CCAP), several orcokinins, and SDRNFLRFamide. This technique also detected corazonin, a well-known insect hormone, in the POs for the first time. However, most mass spectral peaks did not correspond to previously known peptides. To characterize and identify these novel peptides, we performed MALDI postsource decay (PSD) and electrospray ionization (ESI) MS/MS de novo sequencing of peptides fractionated from PO extracts. We characterized a truncated form of previously identified TNRNFLRFamide, NRNFLRFamide. In addition, we sequenced five other novel peptides sharing a common C-terminus of RYamide from the PO tissue extracts. High K+ depolarization of isolated POs released many peptides present in this tissue, including several of the novel peptides sequenced in the current study. 相似文献