• Applied Microscopy
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• v.51
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• pp.11.1-11.9
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• 2021

Spider capture silk is a natural scaffolding material that outperforms most synthetic materials in terms of its combination of strength and elasticity. Among the various kinds of silk threads, cribellar thread is the most primitive prey-capturing type of spider web material. We analyzed the functional organization of the sieve-like cribellum spigots and specialized calamistral comb bristles for capture thread production by the titanoecid spider Nurscia albofasciata. The outer cribellar surface is covered with thousands of tiny spigots, and the cribellar plate produces non-sticky threads composed of thousands of fine nanofibers. N. albofasciata cribellar spigots are typically about 10 ㎛ long, and each spigot appears as a long individual shaft with a pagoda-like tiered tip. The five distinct segments comprising each spigot is a defining characteristic of this spider. This segmented and flexible structure not only allows for spigots to bend individually and join with adjacent spigots, but it also enables spigots to draw the silk fibrils from their cribella with rows of calamistral leg bristles to form cribellar prey-capture threads.

• Animal cells and systems
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• v.13 no.2
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• pp.153-160
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• 2009

The fine structural characteristics of the silk spinning apparatus in the titanoecid spiders Nurscia albofasciata have been examined by the field emission scanning electron microscopy (FESEM). This titanoecid spiders have a pair of medially divided cribella just in front of the anterior spinnerets, and the surface of the cribellum is covered by hundred of tiny spigots which produce numerous cribellate silk fibrils. The cribellar silks are produced from the spigots of the sieve-like prate. and considered as a quite different sort of catching silk with dry-adhesive properties. The other types of the silk spigots were identified as follows: ampullate, pyriform and aciniform glands. Two pairs of major ampullate glands send secretory ductules to the anterior spinnerets, and another 1-2 pairs of minor ampullate glands supply the middle spinnerets. In addition, the pyriform glands send ductules to the anterior spinnerets, and two kinds of the aciniform spigots feed silk into the middle (A type) and the posterior spinnerets (both of A & B types), respectively.

• Applied Microscopy
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• v.33 no.4
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• pp.315-323
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• 2003

The fine structural characteristics of the spinnerets and spigots of the silk producing apparatus in the adult funnel-web spider, Agelena limbata, were analysed with the light and scanning electron microscopes. Silk producing apparatus of this spider was composed of three pairs of spinnerets (anterior, median, posterior) and four different types of spigots-ampullates, tubuliforms, pyriforms and aciniforms. By the examination of their ultrastructural characteristics, it has been revealed that each spigot on the spinnerets are connected through the typical silk gland within abdominal cavity. Among the three pairs of spinnerets, the posterior pairs were highly elongated and has most characteristic features. Two pairs of large ampullates were connected to anterior spinneret and another two pairs of small ampullates to median spinnerets. Spigots of the tubuliforms were observed only in female and were connected both of median and posterior spinnerets respectively. While spigots of the pyriforms were connected on the anterior spinnerets but aciniforms on both of median and posterior spinnerets respectively.

• Applied Microscopy
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• v.39 no.2
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• pp.157-165
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• 2009

Here we demonstrate the fine structural characteristics of the spigots on the cribellum and its peculiar sieve-like structure at the aspects of the functional significance. The surface of the cribellum is covered by hundred of tiny spigots which producing numerous cribellate silk fibrils. It has been known that the cribellar silk is considered as a quite different sort of catching silk with dry-adhesive properties. By our fine structural observation using the field emission scanning electron microscopy (FESEM), the titanoecid spiders have a specialized sieve-like plate just in front of the anterior spinnerets. The other types of the silk spigots were identified as follows: ampullate, pyriform and aciniform glands. Two pairs of major ampullate glands send secretory ductules to the anterior spinnerets, and another 1~2 pairs of minor ampullate glands supply the median spinnerets. In addition, the pyriform glands send ductules to the anterior spinnerets, and the aciniform glands feed silk into the median and the posterior spinnerets, respectively. Characteristically, 2 distinct types (A & B types) of the aciniform spigots were identified in this spider, and the spigots of the aciniform B type are always detected at the posterior spinneret, however sexual dimorphism for spigot is unlikely to be exhibited in this species of spider.

• Journal of Chest Surgery
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• v.46 no.3
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• pp.226-229
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• 2013

Prolonged air leakage is a major cause of morbidity in pneumothorax. When conservative management is not effective, surgery should be performed. However, surgery is not appropriate in patients with low pulmonary function. In these patients, occlusion of the airway with endobronchial blockers may be attempted under bronchoscopy. We treated two patients with prolonged air leakage using endobronchial Watanabe spigots under fibrobronchoscopy.

• Applied Microscopy
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• v.38 no.2
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• pp.89-96
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• 2008

Dolomedes spiders of the family Pisauridae are one of free wandering spiders with semi-aquatic habitation. They do not build web for prey-hunting but build a nursery web for spiderlings. This paper describes the fine structure of the silkspinning spigots of the fishing spider Dolomedes sulfureus revealed by the field emission scanning electron microscope (FESEM). The fishing spider Dolomedes sulfureus possesses only three types of silk glands which connected through the typical spinning tubes on the spinnerets. The silk spigots of this spider were identified as three groups: ampullates, pyriforms and aciniforms. Two pairs of major ampullate glands send secretory ductules to the anterior spinnerets, and another two pairs (or $1{\sim}2$ pairs in males) of minor ampullate glands supply the middle spinnerets. In addition, the pyriform glands feed silk into the anterior spinnerets ($62{\sim}68$ pairs in females and $45{\sim}50$ pairs in males), and the aciniforms send ductules to the middle ($33{\sim}40$ pairs in females and $18{\sim}25$ pairs in males) and the posterior spinnerets ($42{\sim}50$ pairs in females and $24{\sim}28$ pairs in males). Among these, the ampullate one is the most predominate gland in both sexes.

• Applied Microscopy
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• v.25 no.3
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• pp.20-32
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• 1995

Ultrastructural aspects on the production of the duct cuticle and formation of cuticular precursors within silk glands of the orb web spider, Nephila clavata L. Koch(Araneae: Araneidae), were studied using transmission electron microscope. Four kinds of silk glands(ampullate glands, tubuliform glands, flageliform glands, and aggregate glands), which connected with large spinning tubes(spigots) of the spinnerets, were examined and discussed in terms of cuticle precursor production. Inner cuticular intima which composed of three layers of cuticles-subcuticle, endocuticle and exocuticle- were commonly originated from duct epithelial cells surrounding the cuticle. The morphology and internal textures of each cuticle precursors were very diverse according to the types of silk glands. However several common features were observed. These cuticle precursors were first produced from the rough endoplasmic reticulum and next concentration was accomplished through the Golgi complex. After this step, cuticle precursors were released to the cuticle layer as a form of secretory granule by the mechanism of merocrine secretion commonly.

• Applied Microscopy
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• v.19 no.1
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• pp.49-58
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• 1989

Ultrastructure of the excretory duct of the small ampullate gland in the orb web spider, Nephila clavata L. Koch are studied with light and electron microscopes. The small ampullate glands, located near the midline portion of the abdominal cavity, are connected with the spigots(large spinning tubes) on the middle spinnerets and composed of three parts which are the excretory duct, the storage sac and the convoluted tail. The excretory duct of this gland is enclosed by a thin layer of the outer connective tissues. By the morphology of the apical cuticles and internal textures of the epithelial cells, the duct is subdivided into two regions which are proximal duct region near the sac and distal duct region near the spinnerets. At the distal region of the ducts, the subcuticle which had the function of water removal form the progenetive silk material is well developed, whereas at the proximal region this cuticle disappeared and instead of these, endocuticle is developed. Moreover the epithelium of the distal duct region is composed of columnar epithelial cells, but at the proximal region the epithelium is changed to squamous or cuboidal forms. In the cytoplasm of the epithelial cells, rough endoplasmic reticula, Golgi comlexes and large secretory vesicles related to the production of the cuticular materials are well developed. And between the adjacent epithelial cells, specialized septate junction and desmosomes are formed along the plasma membrane.

• Animal cells and systems
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• v.12 no.2
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• pp.109-116
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• 2008

Among the four kinds of silk glands in the funnel-web spider Agelena limbata, the ampullate gland for dragline silk production is the most predominate one in both sexes, and is composed of three functional parts-excretory duct, storage ampulla and convoluted tail regions. Two pairs of major ampullate glands send secretory ductules to the anterior spinnerets, and another two pairs of minor ampullate glands supply the middle spinnerets. There are no apparent differences between the major and minor ampullate glands not only the external spigots but also their internal silk glands. However, the microstructure is very unique in this spider, because each gland has spherical shaped storage sac with twig-like branched tails. Nevertheless, the wall of the secretory region is similarly composed of a single layer of epithelial cells. The mature secretory silks in glandular epithelium are closely packed and accumulated as electron-opaque vesicles. Most of the secretory products which originated from the rough endoplasmic reticula(rER) are grown up by fusion with the surrounding small vesicles however, the Golgi complex does not seem to play an important role in this process of secretion.

• Applied Microscopy
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• v.18 no.2
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• pp.77-90
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• 1988

The ultrastructure of the excretory duct of the large ampullate gland in the orb web spider, Nephila clavain L. Koch are studied with light and electron microscopes. The excretory ducts of the large ampullate glands connected with the large spinning tubes(spigots) on the anterior spinnerets are basically composed of three superposed types of the layers which are inner cuticles, monolayered epithelial cells and peripheral connective cells. According to the morphological characteristics of the cuticles and internal textures of the epithelial cells, the long excretory ducts are subdivided into three(distal, middle and proximal) portions. Especially, at the distal portion of the ducts near the spinning tubes, the electron lucent subcuticles which had the functions of water removal and orientation of silk fibers are well distributed, whereas at the middle and proximal portions these layers disappeared and instead of these, endocuticles are developed. The endocuticle contains two types of bands, which are electron dense and electron lucent. And along the length of the cuticular stem in the excretory duct, these two alternating bands are twisted spirally. In the cytoplasm of the columnar epithelial cells of the distal portion, rough endoplasmic reticula and Golgj complexes, related to the production of the cuticular materials are well developed. Between the adjacent epithelial cells, specialized septate junctions and desmosomes are formed along the plasma membranes. At the proximal portion of the duct, densely accumulated secretory materials appeared, and these are released to the inner canal by the apocrine secretion.