摘要:

SYNOPSISKhawkinea quartana, a naturally occurring colorless homologue ofEuglena, was examined with the electron microscope. The organism is biflagellate though only one of the 2 flagella emerges from the anterior reservoir. The pellicular strips covering the body of the organism are supported by microtubules which are continuous in part with microtubules bordering the reservoir. Additional rows of microtubules are found associated with the kinetosomes. An eyespot is located in the wall of the reservoir and, adjacent to it, the contractile vacuole.The nucleus, mitochondria, and Golgi complexes are similar to those described in other euglenoid flagellates. The food reserve is paramylon.The study supports the phylogenetic origin ofKhawkineafrom pigmentedEuglenathrough the loss of chloroplasts.

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1974.tb03613.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

SYNOPSISA model of the feeding apparatus ofPeranema trichophorumEhrenberg has been constructed from electronmicrographs. A common opening leads via a short anterior canal to the reservoir and cytostome. The cytostome lies close to the internal opening of the canal, and can be moved forward during feeding, closing the passage to the reservoir, and displacing the flagella. The cytostome is supported by the rodorgan in its floor and a double serrated marginal lamella arching over its upper rim from dense bodies lying lateral to the cytostome. A working hypothesis for the movement of the feeding apparatus is proposed. The elaborate system of articulating lamellae operates through these dense bodies which may act as “hinge joints.” The rodorgan is pulled forward by contraction of longitudinal lamellae attached near the bases of the rods. Cytoplasmic pressure may also be involved. It is suggested that the pull is transmitted through the dense bodies and 2 anchoring lamellae to crescentic canal thickenings on either side of the canal opening. The cytostome, rodorgan and double serrated marginal lamella move forward to fill the external opening of the canal, now enlarged by sideways pull from the anchoring lamellae. Withdrawal of these structures sucks food into the cytostomal sac to be packed down by contraction of the double serrated lamella. It is postulated that the rodorgan operates through adhesion and cytolysis and is not adapted for piercing. A conspicuous striated fibril and associated groups of microtubules in the left wall of the reservoir are cytoskeletal structu

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1974.tb03614.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

SYNOPSISThe fine structure of the dividing nucleus in the intracellular amastigote forms ofTrypanosoma cruzifrom tissue cultures has been described. In the first phase of division the nucleus shows a homogenous structure owing to the dispersion of its chromatin and nucleolar material. Microtubules similar to those of a mitotic spindle in metozoan cells then appear, running from one pole to the other. They disappear when the division of the nucleus is complete and the chromatin and the nucleolar material reorganize into their former positions.

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1974.tb03615.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

SYNOPSISUltrastructure of both undifferentiated (promastigote and paramastigote) and differentiated (opisthomastigote) forms ofHerpetomonas megaseliaeis described. There is a posterior migration of the kinetoplast at the end of the exponential growth phase. The posterior extension of the flagellar pocket precedes migration of the kinetoplast. Opisthomastigotes have an electron‐translucent mitochondrial matrix in comparison with undifferentiated forms. The Golgi body changes from a stack of flattened sacs to an aggregation of vesicles. Several structures previously reported from Trypanosomatidae, e.g. subpellicular organelles, pellicular microtubules, membrane whorls, stored metabolic products, surface blebs, and an intraflagellar body are also present inH. megaselia

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1974.tb03616.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

SYNOPSISThe fine structure ofAmoeba discoides, Amoeba dubia, andAmoeba amazonaswas studied and compared with that ofAmoeba proteus. The different kinds of amebas showed general similarities but differed in the ultrastructural details of their organelles. With respect to fine structure,A. discoideswas indistinguishable fromA. proteus, while bothA. dubiaandA. amazonashad distinctive features. The nuclei of all had a prominent honeycomb‐like fibrous lamina, butA. dubiadiffered from the others in the distribution of nucleoli within the nucleus. The mitochondria ofA. amazonaswere unusual in having a variable pattern of cristae, some being plate‐like and others tubular. Golgi bodies inA. amazonashad a greater proportion of vesicles and a smaller number of cisternae than those of the others, while Golgi bodies inA. dubiahad highly flattened cisternae without a lining of filamentous material such as is found in the other types. The plasma membrane ofA. dubiaalso lacked the prominent filamentous cell coat common toA. proteusand other amebas. The relation between the Golgi apparatus and the cell coat and the significance of the degree of development of the cell coat for pinocytosis and other phenomena is considered. The experimental use of these cells, including the formation of hybrids by nuclear transplantation is discus

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1974.tb03617.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

Book reviewed in this article:Stein, Janet R., ed., 1973.Handbook of Phycological Methods. Culture Methods and Growth Measurements.

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1974.tb03618.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

SYNOPSISLight‐ and electronmicroscopic observations onDientamoeba fragilisstrain A (Bi) 1 dealing primarily with the binucleate (arrested telophase) stages, predominant in all populations, revealed the microtubular nature of the extranuclear spindle which extends between the 2 polar complexes each adjacent to one of the nuclei. The spindle microtubules originate in paired, nonperiodic structures apparently homologous to the “atractophores” described from hypermastigotes. To the external surface of the atractophores are applied periodic elements, which extend laterally as the parabasal filaments. Extensive Golgi complexes overlie the filaments, these structures corresponding to the components of the parabasal apparatus known from trichomonads and hypermastigotes. The 2‐layered structures, consisting of the atractophores and periodic layers, together with the proximal parts of the Golgi complex and the spindle microtubules constitute the polar complex. No kinetosome‐ or centriole‐like organelles have been found in the polar complexes or elsewhere in the organism. The extranuclear spindle is composed of 2 microtubule bundles, each with ∼30‐40 microtubules. One of the bundles always appears at some distance from the nucleus; the other is juxtanuclear and is seen often to course within a groove of the nuclear envelope. A 3rd bundle of ∼35‐45 microtubules is seen on occasion to arise from the atractophores and to pass toward the nucleus at a wide angle to the other parts of the spindle. In some instances these microtubules traverse the nucleus within channels delimited by the nuclear envelope. The double‐layered nuclear envelope contains numerous pores. Two morphologic types of rounded inclusions, one microbody‐like, and the other with a more electron‐translucent matrix, as well as digestive vacuoles containing rice starch, bacteria, and/or myelin configurations are distributed in the cytoplasm, which abounds also in glycogen granules.The fine structure ofDientamoebais compared with those of trichomonads and ofEntamoebaspp. The taxonomic position ofDientamoebais discussed and emended; in view of its affinities, this genus is placed among trichomonads in the family Die

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1974.tb03619.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

RESUMELa structure fine du trophozoïte d'Enterocystis fungoidesest voisine de celle décrite chez d'autres Grégarines (Gregarinidae, Stylocephalidae): l'épicyte, la structure fibrillaire de l'ectocyte, les organites cellulaires et les enclaves (amylopectine, mucopolysaccharides) leur sont comparables.Les caractères plus spécifiques sont: (A) l'involution de l'épicyte entre les trophozoïtes associés, due, semble‐t‐il, à l'appariement très précoce de ces trophozoïtes. (B) les évaginations de l'enveloppe nucléaire. Ce bourgeonnement nucléaire semble en rapport avec l'anabolisme de la jeune Grégarine, cellule en croissance semblable à l'ovocyte par maints caractères: augmentation considérable des dimensions du noyau et du nucléole, accumulation de ribosomes et de substances de réserve dans le cytoplasme.SYNOPSISThe fine structure of the trophont ofEnterocystis fungoidesdoes not differ widely from the ultrastructural organization described in other Gregarines (Gregarinidae, Stylocephalidae). The epicyte, the fibrillar structure of the ectocyte, the cell organelles and inclusions (paraglycogen = amylopectin, mucopolysaccharides) are similar.Its specific peculiar features are the following: (A) The involution of the epicyte between the biassociative trophonts, due to their early pairing. (B) The evaginations of the nuclear envelope. It seems advisable to connect this nuclear budding with the anabolic activity of the young gregarine, a developing cell similar in many features to an ovocyte: increasing of the size of nucleus and nucleolus, accumulation of ribosomes and reserve su

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1974.tb03620.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

RESUMELe cortex de la face dorsale (non ciliée) ne contient pas de cinétosomes; sous des alvéoles bien développés se trouve un épiplasme épais, puis une couche irrégulière de microtubules longitudinaux; de nombreux pores cylindriques traversent le cortex. La région ventrale, limitée aux faces internes des 2 lèvres apicales, porte la ciliature somatique répartie en 2 champs inégaux (droit>gauche). Chaque cinétie somatique comporte une seule rangée de cinétosomes qui, tous, possèdent des formations fibrillaires associées: (a) dérivés classiques: fibres transverses, fibres postciliaires, fibre cinétodesmale; (b) une lame transverse gauche, dense, accompagnant les fibres transverses; (c) une couche de microtubules sous‐cinétiens s'étendant vers l'avant de la cinétie.L'existence d'une ciliature buccale spécialisée est démontrée; elle consiste en une cinétie “circumorale” don l'infraciliature est faite de paires de cinétosomes (1 cilifère, l'autre non), que ne sont pas des dyades; de ce fait, cette infraciliature n'est pas l'equivalent de celle d'une membrane ondulante ou d'une parorale de Cilié des Ordres supérieurs. De plus, sa polarité antéro‐postérieure est inversée par rapport à celle des cinéties somatiques, donc par rapport à celle du Cilié; elle est accompagnée sur sa droite par quelques cinéties somatiques (3 au maximum) qui sont également inversées; il est probable que ces inversions résultent de mouvements morphogénétiques identiques à ceux qui se produisent lors de la stomatogénese chez les Chlamydodontidae et les Dysteriidae. Aucune armature de némadesmes n'entoure le cytopharynx; ce dernier est soutenu par des rideaux de microtubules qui lui donnent un aspect feuilleté trèe particulier, et le phagoplasme qui l'accompagne renferme des tubules complexes (vermicelles).L'organisation du cortex dorsal est comparée à celle d'autres Ciliés de divers groupes. Les formations fibrillaires associées aux cinétosomes somatiques sont identiques à celles décrites chez des Chlamydodontidae, des Dysteriidae, certains Rhynchodina et les bourgeons ciliés de certains Acinétiens.La disposition et la constitution de l'infraciliature somatique, la présence et les caractéristiques d'une différenciation infraciliaire périorale (“circumorale”), l'aspect feuilleté de la paroi cytopharyngienne, la présence de tubules complexes (vermicelles) dans le phagoplasme, l'origine de l'appareil fixateur, l'héteromérie du macronoyau, sont autant de caractères communs avec les families Chlamydodontidae et Dysteriidae. Aussi, une révision systématique est envisagée, avec l'établissement de 2 sous‐ordres, proches l'un de l'autre, et appartenant à l'ordre des Hypostomatida: S/O Chonotrichina et S/O Cyrtophorina (ce dernier limité aux seules families Chlamydodontidae et Dysteriidae).SYNOPSISThe non‐ciliated dorsal cortex is devoid of kinetosomes, but perforated with numerous pores; it contains large alveoli, an important epiplasm and an irregular sheet of longitudinal microtubules. The ventral side is confined to the internal faces of the 2 apical lips which bear 2 unequal fields of somatic ciliature (right>left). A somatic kinety has only one line of kinetosomes, the associated fibers of which are: (a) classical derivatives: transverse, postciliary and kinetodesmal fibers; (b) a dense transverse spur, running along the transverse fibers; (c) a sheet of subkinetal microtubules extending forward along the kinety.The special buccal ciliature is a “circumoral kinety,” the infraciliature of which is composed of pairs of kinetosomes (1 ciliated, 1 nonciliated), which are different from dyades; so, this circumoral kinety is not homologous to the UM of ciliates included in superior orders. Furthermore, its anteroposterior polarity is inverse with regard to that of the somatic kineties and that of the cell; the circumoral kinety is accompanied by some inverse somatic kineties (maximum 3); all these inversions are probably the result of morphogenetic movements analogous to these which are described in the stomatogenesis of Chlamydodontidae and Dysteriidae. The wall of the cytopharynx is composed of overlapping sheets of microtubules. “Vermicelles” form the phagoplasm. Nemadesmata are absent.The dorsal cortical organization is compared with that of other ciliates. The fibers associated with somatic kinetosomes are identical to those of Chlamydodontidae, Dysteriidae, rhynchodine Ancistrocomidae, and ciliated buds of some Acineta.All the characteristics (somatic infraciliature and its derivates, cytopharyngeal wall, vermicelles, origin of the fixative apparatus, heteromerous macronucleus) are common forChilodochonaand the 2 families Chlamydodontidae and Dysteriidae. A revision of the systematics is envisaged, with the establishment of 2 new close suborders, belonging to the order Hypostomatida: S/O Cho

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1974.tb03621.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

SYNOPSISThe phoront of the apostomatous ciliate,Hyalophysa chattoni, is an encysted stage that is carried on the exoskeleton of its crustacean host until the ecdysis of the host. At molting the phoront rapidly metamorphoses to the feeding stage, excysts, and immediately begins to feed on exuvial fluid trapped in the cast‐off exoskeleton. The fine structure of the resting phoront resembles that of the preceding migratory stage, the tomite. A prominent ventral tuft of cilia, the ogival field, has vanished, and the trichocysts that paralleled the kinetics have disappeared. The dense inclusion bodies that were concentrated around the mouth and falciform fields have dispersed and greatly decreased in number. The cytoplasm and its membranous organelles do not appear visibly condensed or altered from the preceding stage in the life cycle. The phoront is merely quiescent instead of dormant.Unlike the few ciliate cysts previously examined by electron microscopy, the phoront's cyst is not divisible into separable layers. It resembles the loricae of certain suctoria in being formed principally of a fibrous substance, the outer surface of which has a paracrystalline pattern. The peduncle attaching the cyst to the crab's gill is a continuation of the cyst wall although its structure is somewhat modified.The most conspicuous innovation in the phoront's fine structure is the massive tracts of microtubules that run longitudinally through the macronucleus. The microtubules are in intimate contact with Feulgen‐positive chromatin masses which are crowded toward the periphery of the macronucl

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1974.tb03622.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY