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509372. Ultrastructure of the frontal gland in Prorhinotermes simplex (Isoptera: Rhinotermitidae) and quantity of the defensive substance
- Creator:
- Šobotník, Jan, Weyda, František, Hanus, Robert, Kyjaková, Pavlína, and Doubský, Jan
- Type:
- article, model:article, and TEXT
- Subject:
- Ultrastructure, frontal gland, termite, Isoptera, Rhinotermitidae, Prorhinotermes simplex, Prorhinotermes inopinatus, intercaste, defence secretion, and E-1-nitropentadecene
- Language:
- English
- Description:
- The frontal gland as a sac-like organ in Prorhinotermes simplex is present only in presoldiers, soldiers, and imagoes, but exists also in nymph-soldier intercastes. The secretory epithelium consists of a single type of secretory cells adhering directly to the cuticular intima. Secretory vacuoles originate in electron dense vesicles, which are transformed into large electron lucent vacuoles. Intermediate vacuoles frequently contain lipid droplets. The frontal gland cells in presoldiers reveal modifications connected with the production of a new cuticle; the new cuticle is thin and compact, whereas the old one is thick, porous, and wrinkled. None of these cuticles is present in soldiers (sic!). In soldiers, the cuticular intima is of endocuticular origin and is formed by dispersed dense material; the apical parts of secretory cells are formed by numerous irregular finger-like projections, true microvilli are completely lacking. In imagoes, the cuticle is composed of an epicuticle, a layer of epicuticular filaments, and one more basal layer; sexual differences were not observed. In nymph-soldier intercastes, the structure of the gland differs in the head and in the metathorax; the head part of the gland resembles the imaginal gland whereas the thoracic part resembles more that of the soldier; the development of secretory vacuoles stops at the stage of presence of lipid droplets. E-1-nitropentadecene was found in the highest amount in soldiers (comparable to P. inopinatus soldiers), in moderate amount in imagoes, and it is missing in both presoldiers and intercastes.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
509373. Ultrastructure of the gastrodermis and posterior gut pockets of Concinnocotyla australensis (Platyhelminthes, Monogenea, Polystomatidae) and comparison with another polystomatid, Neopolystoma spratti
- Creator:
- Watson, Nikki A. and Whittington, Ian D.
- Format:
- Type:
- model:internalpart and TEXT
- Subject:
- gastrodermis, ultrastructure, Polystomatidae, and Platyhelminthes
- Language:
- English
- Description:
- While the majority of polyopisthocotylean monogeneans feed on blood, some polystomatids infecting chelonians do not. This study examined the gastrodermis of two polystomatids, one - Neopolystoma spratti Pichelin, 1995 - from the conjunctival sac of a chelonian and the other - Concinnocotyla australensis (Reichenbach-Klinke, 1966) - from the oral cavity, gill arches and primary gill lamellae of a fish, and also found no evidence of blood feeding. However, the gastrodermal architecture in both species basically resembles that found in blood feeding polyopisthocotyleans, with alternation of lamellated digestive cells and an intervening syncytium. In C. australensis, oesophageal secretion appeared to be responsible for initial extracellular digestion and this was followed by pinocytotic uptake of partly degraded material in pits between the numerous apical lamellae of digestive cells. Posterior dorsolateral gut pockets unique to C. australensis were shown to be blind sacs separated from the external environment by a narrow cytoplasmic bridge, composed of a thin layer of tegument apposed to a thin layer of pocket syncytial epithelium. The pockets are lined with greatly folded syncytium and set in a “capsule” of tissue in which numerous pro-tonephridial flame cells are embedded. It is suggested that the pockets have an osmoregulatory function related to the particular environment and evolutionary history of the host, the primitive lung fish (Dipnoi) Neoceratodus forsteri (Krefft, 1870).
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
509374. Ultrastructure of the ovarian follicles, oviducts and oocytes of Gyrocotyle urna (Neodermata: Gyrocotylidea)
- Creator:
- Poddubnaya, Larisa G., Kuchta, Roman, Scholz, Tomáš, and Xylander, Willi E.R.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- Platyhelminthes, comparative morphology, TEM, ovary, oocapt, ovarian receptacle, and fertilisation canal
- Language:
- English
- Description:
- An ultrastructural study of the ovarian follicles and their associated oviducts of the cestode Gyrocotyle urna Grube et Wagener, 1852, a parasite from the spiral valve of the rabbit fish, Chimaera monstrosa L., was undertaken. Each follicle gives rise to follicular oviduct, which opens into one of the five collecting ducts, through which pass mature oocytes. These collecting ducts open into an ovarian receptacle which, in turn, opens via a muscular sphincter (the oocapt) to the main oviduct. The maturation of oocytes surrounded by the syncytial interstitial cells within the ovarian follicles of G. urna follows a pattern similar to that in Eucestoda. The ooplasm of mature oocytes contain lipid droplets (2.0 × 1.8 µm) and cortical granules (0.26 × 0.19 µm). The cytoplasm of primary and secondary oocytes contains centrioles, indicating the presence of the so-called ''centriole cycle'' during oocyte divisions. A morphological variation between different oviducts was observed. The luminal surface of the follicular and the collecting oviducts is smooth. The zones of the septate junctions are present within the distal portion of the net-like epithelial wall of the collecting ducts close to the ovarian receptacle. The syncytial epithelial lining of the ovarian receptacle, oocapt and main oviduct is covered with lamellae and cilia. Cortical granules secreted from mature oocytes occur freely within the lumen of the main oviduct that functions as a fertilisation canal. A division of the ovary into separated parts with their own collecting ducts as that typical of Gyrocotyle has been observed in neodermates, basal monogenean family Chimaericolidae, and Neoophora (some Proseriata and Fecampiidae). Ultrastructural data thus reveal several unique morphological characteristics of gyrocotylideans, the most basal taxon of tapeworms (Cestoda).
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
509375. Ultrastructure of the primitive epithelium of Echinostoma revolutum (Digenea: Echinostomatidae) cercaria
- Creator:
- Žďárská, Z.
- Format:
- Type:
- model:internalpart and TEXT
- Subject:
- Digenea, Echinostoma revolutum, cercaria, primitive epithelium, and TEM
- Language:
- English
- Description:
- Ultrastructure of the primitive epithelium of Echinostoma revolutum (Digenea: Echinostomatidae) cercaria was studied. The germinal balls and developing cercariae are covered with the primitive epithelium in daughter rediae. When the definitive tegument of the cercaria is differentiated, the primitive epithelium degenerates. The last remnants of the primitive epithelium in a cercaria can be detected at the stage when the lateral gland cells have released their secretion into the definitive tegument.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
509376. Ultrastructure of the scolex, rhyncheal system and bothridial pits of Otobothrium mugilis (Cestoda: Trypanorhyncha)
- Creator:
- Jones, Malcolm K.
- Format:
- Type:
- model:internalpart and TEXT
- Subject:
- Cestoda, ultrastructure, rhyncheal system, scolex, and Trypanorhyncha
- Language:
- English
- Description:
- The ultrastructure of the scolex tegument, bothridial pits (“ciliated pits) and rhyncheal system of Otobothrium mugilis Hiscock, 1954 is described from plerocerci collected from the teleosts Arius graeffei Kncr ct Steindachner and Mugil cephalus Linnaeus. Scanning electron microscopy revealed that filamentous microtriches with shortened caps are abundant across the entire surface of the tegument. Palmate microtriches are dominant on the bothridia and their margins. The surfaces of bothridial pits were covered with large bifid microtrichcs. The bothridial pits arc strongly muscularised invaginations of the tegument. Nervous tissues were not observed within the pits and it is probable that these structures function as accessory attachment structures. The wall of each tentacle sheath consists of one to three bands of fibrils, lined internally by a thin cytoplasmic layer. The tentacular walls are cellular, containing myofilaments. The fibrils of the tentacular walls are arranged into discrete blocks of parallel fibrils and appear to be intracellular. Tentacular walls are lined externally by a modified membrane with an external glycocalyx. Tentacular hooks arc solid, bound externally by a membrane. The body of the hook contains numerous longitudinal canaliculi and an elcctron-opaquc medulla lies at the centre of the hook.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
509377. Ultrastructure of the secondary osmoregulatory canals in the scolex and neck region of Silurotaenia siluri (Batsch, 1786) (Cestoda: Proteocephalidae)
- Creator:
- Žďárská, Zdeňka and Nebesářová, Jana
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Language:
- English
- Description:
- The secondary osmoregulatory canals in the scolex and neck region of Silurotaenia siluri, a parasite of the catfish Silurus glanis (L.), terminate below the tegument basal plasma membrane. The basal plasma membrane of the osmoregulatory canal syncytium is in tight contact with the tegument basal plasma membrane.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
509378. Ultrastructure of the spermatozoon of the digenean Lecithocladium excisum (Rudolphi, 1819) (Hemiuroidea: Hemiuridae), a parasite of marine teleosts in Senegal
- Creator:
- Ndiaye, Papa Ibnou, Diagne, Papa Mbagnick, Sène, Aminata, Bakhoum, Abdoulaye J. S., and Miquel, Jordi
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- Lecithocladium excisum, Hemiuridae, Digenea, spermatozoon, ultrastructure, Scomber japonicus, Scombridae, fish, and Senegal
- Language:
- English
- Description:
- The present study describes the ultrastructure of the mature spermatozoon of Lecithocladium excisum (Rudolphi, 1819) (Digenea: Hemiuroidea: Hemiuridae) from the stomach of the marine teleost Scomber japonicus Houttuyn (Scombridae) captured in the Atlantic Ocean, off Dakar (Senegal). The ultrastructural organization of the spermatozoon of L. excisum follows the general model described in most digeneans. It presents two axonemes of the 9+'1' pattern of the Trepaxonemata, nucleus, mitochondrion and parallel cortical microtubules, among other characters. However, some particularities of the spermatozoon of L. excisum are (i) the presence of a membranous ornamentation not associated with cortical microtubules in its anterior extremity, (ii) the presence of a very reduced number of cortical microtubules located only in the ventral side of the spermatozoon and (iii) the absence of several structures described in most digeneans such as spine-like bodies and cytoplasmic expansions.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
509379. Ultrastructure of the spermatozoon of the trematode Notocotylus noyeri (Digenea: Notocotylidae), a parasite of Microtus arvalis (Rodentia: Cricetidae)
- Creator:
- Ndiaye, Papa Ibnou, Torres, Jordi, Eira, Catarina, Shimalov, Vladimir V, and Miquel, Jordi
- Format:
- electronic, počítač, and online zdroj
- Type:
- model:article and TEXT
- Subject:
- ploštěnci, cytochemie, Platyhelminthes, cytochemistry, Pronocephaloidea, sperm characters, TEM, 2, and 59
- Language:
- English
- Description:
- In the present paper, we describe the ultrastructure of the spermatozoon of the notocotylid Notocotylus noyeri (Joyeux, 1922) by means of transmission electron microscopy. The mature spermatozoon of N. noyeri exhibits the general pattern described in the majority of digeneans: two axonemes of the 9 + "1" pattern of the Trepaxonemata, nucleus, mitochondria, parallel cortical microtubules, spine-like bodies and ornamentation of the plasma membrane. The glycogenic nature of the electron-dense granules was evidenced applying the test of Thiéry. The ultrastructural features of the spermatozoon of N. noyeri present some differences in relation to those of the Pronocephalidea described until now, but confirm a general pattern for the Notocotylidae, namely a spermatozoon with two mitochondria and an anterior region with ornamentation of the plasma membrane associated with spine-like bodies. The posterior extremity of the spermatozoon exhibits only some microtubules after the disorganisation of the second axoneme. The present study confirms that some ultrastructural characters of the sperm cell such as the presence or absence of lateral expansions, the number of mitochondria and the morphology of both anterior and posterior spermatozoon extremities are useful for phylogenetic purposes within the Pronocephaloidea. Thus, unlike notocotylids, pronocephalids exhibit external ornamentation and a lateral expansion in the anterior spermatozoon region. Moreover, notocotylid spermatozoa present two mitochondria, whereas pronocephalid spermatozoa exhibit a single mitochondrion. Finally, pronocephalids are characterised by a type 2 posterior spermatozoon extremity, whereas notocotylids exhibit a type 3 posterior spermatozoon extremity., Papa Ibnou Ndiaye, Jordi Torres, Catarina Eira, Vladimir V. Shimalov, Jordi Miquel., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
509380. Ultrastructure of the surface structures and secretory glands of the rosette attachment organ of Gyrocotyle urna (Cestoda: Gyrocotylidea)
- Creator:
- Poddubnaya, Larisa G., Scholz, Tomáš, Kuchta, Roman, Levron, Céline, and Gibson, David I.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- Cestoda, Gyrocotylidea, Gyrocotyle urna, rosette organ, adhesive secretion, secretory glands, and ultrastructure
- Language:
- English
- Description:
- The surface structures and gland cells of the posterior rosette organ of Gyrocotyle urna Grube et Wagener, 1852, a member of the group presumed to be the most basal of the tapeworms (Cestoda: Gyrocotylidea), was studied by scanning electron and transmission electron microscopy. Surface structures on the outer (oriented away from the intestinal wall) and inner (in contact with the intestinal wall) rosette surfaces differ from each other and represent a transitional form between microvilli and microtriches typical of tapeworms (Eucestoda). The inner surface of the rosette possesses numerous glands. On the basis of the size and electron-density of their secretory granules, three types of unicellular gland cells can be distinguished. The least common type (Type I) is characterized by the production of small, round, electron-dense granules of about 0.3 µm in diameter, whereas another type of secretion (Type II) is formed from homogenous, moderately electron-dense, spheroidal granules of about 0.7 µm in diameter. The most common type of glands (Type III) is recognized by a secretion comprising large, elongate, electron-dense granules of about 1 µm long and 0.5 µm broad. The secretory granules of the three types of the glands are liberated by an eccrine mechanism and the gland ducts open via small pores on the inner rosette surface. The complex of secretory glands of the posterior rosette of G. urna is similar to those in the anterior attachment glands of monogeneans (as opposed to the types of glands present in other helminth groups). However, the tegumental surface structures of Gyrocotyle are supporting evidence for the relationship between the Gyrocotylidea and Eucestoda.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public