摘要:

ABSTRACT.A heat‐stable chemoattractant has been isolated from bacterial cultures. This component has a molecular weight in the range of 500–1000 daltons, is produced by both Gram‐positive and Gram‐negative bacteria, and serves equally well as an attractant for both the bacterial feedingParameciumand for its natural predator,Didinium. Aspects of the ecological relationship between bacterial feeding ciliates and their ciliate predators are briefly discussed with respect to responses of both predator and prey to such a common chemotactic bacterial

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1983.tb01033.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

ABSTRACT.Herpetomonas megaseliae, Crithidia fasciculata, andLeptomonas collosomafrom culture survived gut passage inAnolis carolinensisfollowing their ingestion by this lizard. Maximum persistence ofH. megaseliaein lizards, as detected by fecal culture, was seven days. No invasion of tissues byH. megaseliaecould be detected by means of sectioned material, stained impression slides, or cultures inoculated with material from organs.Crithidia fasciculatawas evident in cloacal fluid for up to three days in wet mount preparations.Leptomonas collosomawas observed in feces 24 h after the organisms were fed to lizards. BothC. fasciculataandL. collosomawere cultured from feces of lizards fed the parasites 24 h earlier.Herpetomonas megaseliaewas differentiated in lizard feces, with greater than 40% of the forms observed being paramastigotes or opisthomastigotes. Truncate, semispherical forms resembling choanomastigotes were seen, but the kinetoplast was posterior to the nucleus in some of these. Many forms showed extensive coiling of the axoneme within the body of the flagellate. Choanomastigotes and spheromastigotes ofC. fasciculataand promastigotes, sphero‐mastigotes and amastigotes ofL. collosomawere also observed in the fece

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1983.tb01034.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

ABSTRACT.Oxytrichastrains used in biochemical studies have traditionally been grown in unaerated, unagitated culture tubes or Fernbach flasks. These cultures are limited in volume to about one liter and have a very nonuniform distribution of cells, with the majority of the cells at the very top or bottom of the medium. We have found conditions in whichOxytrichacan be grown in 50‐liter fermentation vats. The cultures grow to a uniform density of about 6000 cells/m

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1983.tb01035.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

RESUME.Dans la région antérieure deSpirochona gemmipara, l'emploi combiné de la microscopie à contraste interférentiel (No‐marski), des colorations au protargol et de la microscopie électronique à transmission révèle l'existence d'un appareil cytoproctal et d'un système excréteur (“contractile vacuole complex”), lesquels ont souvent été confondus entre eux ou avec le cytopharynx. L'appareil cytoproctal comprend un orifice externe situéà la base de la collerette, un canal cytoproctal long d'environ 20 μm limité par une pellicule alvéolaire, et le cytoprocte proprement dit. Le système excréteur est formé de 6 à 8 canaux sinueux pouvant mesurer jusquà 20 μm de long et s'ouvrant chacun par un pore situé sur la face interne de la collerette, parmi la ciliature. L'ostium, c'est‐à‐dire l'orifice profond de chaque canal, est en relation avec une vacuole dans laquelle aboutit un spongiome tubulaire bien développé. Bien que profondément enfoncés dans le cytoplasme, le cytoprocte et les ostia du spirochone ne semblent pas fondamentalement diffêrents des organites correspondants

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1983.tb01036.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

ABSTRACT.The fine structure of the tomite ofFoettingeria actiniarum(Claparède) was examined and compared with that of other apostome tomites. This stage in the life cycle has a unique configuration of kineties that form a spiral through the cytoplasm in the interior of the body. The structure and behavior of this internal spiral were evaluated as a mechanism for the storage of kinetosomes, an adaptation to the ciliate's two‐host life cycle. The spiral is composed of nine ribbons of laterally compressed kinetosomes that are in contact with a thin electron‐dense fibril. Paralleling the kineties of the spiral are conspicuous, swollen lamellae of the rough endoplasmic reticulum; these lamellae contain moderately electron‐dense material. The spiral is associated with the large contractile vacuole and winds about the macronucleus. The tomite ofFoettingeriapossesses a single, robust, caudal cilium located in a pit, along with the nozzle‐like pore of the contractile vacuole. The walls of the pit contain several trichocysts arranged radially about the caudal cilium and aimed into

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1983.tb01037.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

ABSTRACT.The ultrastructure of the cortex beneath the fission furrow of dividingStentor coeruleuswas examined using scanning and transmission electron microscopy. During division, basal bodies, axonemes, and km fibers beneath the furrow were absorbed near the moving primordial oral apparatus, and a circumferential band of microtubules and filaments was formed at the base of the furrow. The location and orientation of this fibrous band suggest that it may be an important component of the cytokinetic machinery. Treatment with vinblastine sulfate (4 × 10‐5M) disrupted the circumferential microtubules and blocked division, which is consistent with this hypothes

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1983.tb01038.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

ABSTRACT.To answer whetherBlepharisma hyalinumis truly unpigmented, the organism must be established in culture as pointed out by Giese in 1973. Accordingly, the present study deals withB. hyalinumkept in culture since its isolation in 1975. The organism still remains colorless after growth in the dark; however, it contains cortical granules resembling pigment granules in colored species. A comparative study was therefore undertaken ofB. hyalinumandB. steini; both species have a compact macronucleus, though of different shape. Crude pigment was extracted with acetone from organisms grown in the dark for three weeks and the maxima were measured by absorption. Purified pigment was obtained from TLC‐plate preparations and the absorption maxima were measured after removal of lipids with chloroform. No maxima characteristic of blepharismin were found in extracts ofB. hyalinum, but these were present in extracts ofB. steini.Electron microscopy of the cortical region revealed membrane‐bound granules in both species; these granules differed in content but not in their capacity to extrude. InB. hyalinumall granules had a homogenous electron‐dense substructure; inB. steinithe granules had a net‐like granulated substructure of varying electron density. This difference corresponds to that published on “pigment” granules in albino and pigmented strains ofB. undulans.Our conclusions are thatB. hyalinumis unpigmented (and a valid separate species) and that the cortical granules may serve other functions than that of storing b

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1983.tb01039.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

ABSTRACT.The structure and ultrastructure of the chitinous lorica ofEufolliculinasp. are described. The lorica is produced from precursor material secreted by the motile swarmer immediately after settling. This material is located in numerous vesicles found in the cortical region of the cells and is secreted by exocytosis. Initially, material is secreted from the ventral part of the cell to produce the attachment plate of the lorica. After this, exocytosis occurs over most of the body surface as the ampulla part of the lorica is constructed. During the later stages of lorica formation, secretion is mainly limited to the anterior of the cell as the neck is formed. The lorica is shaped mainly by the action of the cilia and by the behavior of the cell. While the neck is being formed, the anterior part of the cell is deformed by a local accumulation of cytoplasmic vacuoles. This deformation is employed in shaping the neck. No changes were detected in the organization of the cortical infraciliature during the first stages of lorica formation, but they do occur after the neck has been produced and as the swarmer develops into the sessile form.

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1983.tb01040.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

ABSTRACT.Ultrastructural cytochemical techniques were used to analyze the nucleus and the kinetoplast of epimastigotes ofTrypanosoma cruzi.With the use of ethanolic phosphotungstic acid, which detects basic proteins, reaction product was seen in the chromatin and at the periphery of the kinetoplast. Thallium alcoholate, which interacts with DNA, stained strongly the whole kinetoplast and the chromatin. With the use of a silver impregnation method that detects acidic nucleolar proteins, silver granules were seen preferentially located in the central region of the nucleolus. With the EDTA method, which reveals the presence of ribonucleoproteins, staining was observed in the nuclear pores. Also 6–8 nm fibrils, 25 nm and 40 nm granules, which correspond to the perichromatin fibers, interchromatin granules and the perichromatin granules, respectively, were identified in the nucleus. The EDTA method also revealed the presence of 40 nm granules in the kinetoplast. These granules were seen mainly at the two extremities of the kinetoplast. Freeze‐fracture images indicate that the nuclear membrane contains ca. 9 pores/μm2of nuclear surface area. The mean diameter of the pores was 80 nm. All these results suggest that epimastigotes ofT. cruzihave a very active nucleus and a high rate of nucleocytoplasmic interch

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1983.tb01041.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

ABSTRACT.Fine structural studies of a specialized vesicle system associated with the endoplasmic reticulum (ER) of exo‐erythrocyticPlasmodium bergheisuggest that this system may be the equivalent of a Golgi apparatus. Patches of ER, randomly distributed in the cytoplasm of developing parasites, are formed of smooth and ribosome‐studded cisternae intermingled with each other. The vesicle systems are located between as well as at the edges of ER aggregates and appear to be in different stages of budding from the cisternae. Prolonged osmication reveals distinct staining of the nuclear envelope and ER of the parasites as well as part of the Golgi apparatus of the hepatocytes. However, the small vesicles associated with the parasite's ER are unstained, as are the coated vesicles in the Golgi region of the liver cell. These sites in the parasite cytoplasm seem comparable to the concave surface of the Golgi apparatus in liver cells. The pinched‐off vesicles fuse with others to form the prominent peripheral vacuolization characteristic of the nearly mature exo‐erythrocytic form. The formation of these peripheral vacuoles and their subsequent fusion with the parasite membrane may be an exocytosis mechanism supplying the rapidly expanding parasite with new plasma membrane m

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1983.tb01042.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY