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1.
A new armored dinoflagellate species, Heterocapsa psammophila Tamura, Iwataki et Horiguchi sp. nov. is described from Kenmin‐no‐hama beach, Hiroshima, Japan using light and electron microscopy. This dinoflagellate possesses the typical thecal plate arrangement of the genus Heterocapsa, Po, cp, 5′, 3a, 7′′, 6c, 5s, 5′′′, 2′′′′; and the 3‐D body scales of Heterocapsa on the plasma membrane. The cell shape is ovoidal. The spherical nucleus and the pyrenoid are situated in the hypotheca and the epitheca, respectively. The ultrastructure of H. psammophila is typical of dinoflagellates and the pyrenoid is invaginated by cytoplasmic tubules. H. psammophila is distinguished from all other hitherto‐described Heterocapsa species by the cell shape, the relative position of the nucleus and pyrenoid and the structure of the body scale. The habitat and behavior of this new species in culture suggest that the organism is truly a sand‐dwelling species. 相似文献
2.
Terumitsu Hori 《Journal of phycology》1973,9(2):190-199
The pyrenoid structure in 15 species of the Monostroma complex is very diverse us revealed by a study of the morphology of the pyrenoid matrix, associated starch shell, and pattern of intrapyrenoidalthylakoid bands. From these characteristics 8 types of pyrenoid structure were classified. The variation of pyrenoid structure was shown not only among the species studied, but also between the alternation of generations (M. angicava and M. nitidum). In M. fuscum var. splendens, M. groenlandicum, M. undulatum, and M. zostericola pyrenoid structure is the same throughout the life cycle. The pyrenoid matrix of M. zostericola is surrounded by a double membrane that prevents the direct connection of the pyrenoid matrix with chloroplast thylakoids. The pyrenoid also lacks a starch shell. These findings support the establishment of a new genus Kornmannia by Bliding to include M. zostericola. In addition, similarities in pyrenoid ultrastructure suggest an affinity of Capsosiphon fulvescens with M. groenlandicum. 相似文献
3.
The structure of the pyrenoid supports the separation of Chlorella species into two groups based on cell wall chemistry and suggests evolutionary relationships. Chlorella species with a glucan-type wall exhibit quite diverse pyrenoid structures, which may indicate that these species are not closely related. Those species with glucosamine cell walls (C. kessleri, C. sorokiniana, C. vulgaris) are virtually identical in pyrenoid morphology, indicating a closer evolutionary relationship. In the species with glucosamine walls, the thylakoid that penetrates into the pyrenoid matrix, is unijormly double-layered. Pyrenoids in the species with glucan walls show various features: 1) a pyrenoid matrix only, 2) a pyrenoid traversed by a few discs of double thylakoids with many adhering pyrenoglobuli, 3) a pyrenoid penetrated with tubelike structures or 4) a pyrenoid penetrated with many single undulating thylakoids. The pyrenoid structure of the symbiotic Chlorella in Paramecium bursaria resembles those of free-living Chlorella with glucosamine walls. 相似文献
4.
The ultrastructure, morphology and life cycle of a new chlorarachniophyte alga collected from Okinawa in Japan have been studied. The life cycle of this alga consists of amoeboid, wall‐less round, coccoid and flagellated cells in culture condition; however, the coccoid and flagellate cells are very rare. The pyrenoid ultra‐structure of this alga is the same as that of a previously described species, Lotharella globosa. Since pyrenoid ultrastructure has been adopted as the main criterion for the generic classification of the chlorarachniophytes, the present alga is placed in Lotharella. However, the present alga has a dominant amoeboid cell stage and a reduced walled‐cell stage in the life cycle, while in L. globosa, the walled‐cell stage is dominant and there is no amoeboid cell stage. Therefore the present alga is described as a new species of Lotharella: Lotharella amoeboformis Ishida et Y. Hara sp. nov. 相似文献
5.
Chloroplast inclusions have been studied in zoospores of Oedocladium carolinianum and their ultrastructure compared with the same inclusions previously described in the related genera Oedogonium and Bulbochaete. Structure of the mature pyrenoids is consistent in all 3 genera; the pyrenoid matrix is penetrated by branched cytoplasmic channels delimited by a double membrane system continuous with the chloroplast envelope. Pyrenoids typically arise de novo in zoospores of O. carolinianum. No evidence for the bipartition of a parent pyrenoid has been observed. The incipient pyrenoids of Oedocladium are similar to those found in zoospores of Oedogonium and Bulbochaete, but they frequently demonstrated a crystalline matrix. However, a crystalline matrix was never observed in any mature pyrenoid, even those immediately adjacent to incipient pyrenoids with crystalline structure. Other chloroplast inclusions typical of Oedogonium and Bulbochaete zoospores are the eyespot and striated microtubules. Although the zoospores of O. carolinianum possess striated microtubules, the presence of an eyespot has not been observed. 相似文献
6.
Trebouxia sp., the phycobiont of the lichen Ramalina menziesii Tuck., was examined with the electron microscope. Its pyrenoid is characterized structurally as being permeated by interconnected vesiculate membrane systems associated with osmiophilic globules termed pyrenoglobuli. The variety of membrane structure associated with the pyrenoid has been documented with electron micrographs. A model based on serial sections was constructed to show the extent of vesiculation, to demonstrate that the pyrenoglobuli within the pyrenoid matrix are invariably adjacent to the thylakoid membranes within that, matrix, and to emphasize the recurrent thylakoid membrane to pyrenoglobuli relationship. A comparison of the glutaraldehyde-osmium fixation image of the pyrenoglobuli and pyrenoid matrix with the permanganate fixation image has been included. The structure of the pyrenoid matrix in thin section was examined and appears essentially granular. 相似文献
7.
Carole A. Lembi 《Journal of phycology》1975,11(1):1-9
The fine structure of the flagellar apparatus of 5 species of the green quadriflagellate alga Carteria is described. The 5 species can be morphologically separated into 2 groups on the bases of cell shape and ultrastructure of the pyrenoid and flagellar apparatus. Group I cells are spherical, possess many pyrenoid thylakoids, and retain a flagellar apparatus similar to that of Chlamydomonas reinhardi. The flagellar bases are oriented at approximately 90° to one another, have distal and proximal fibers, and are associated with 4 cruciately arranged microtubule bands. Cells of group II are ellipsoid, possess few pyrenoid thylakoids, and show a complex system of microtubule bands and sigmoid-shaped, electron dense rods which extend between opposite pairs of basal bodies. The basal bodies of group II cells are directed inward in a circular pattern rather than outward as in group I cells. Unlike Chlamydomonas, the distal fiber of the Carteria species is nonstriated. The proximal fiber is striated, and both distal and proximal fibers are composed of 60–80 Å diameter microfibrils. 相似文献
8.
The fine structure of the pyrenoid in the mature vegetative cell of Tetracystis excentrica Brown and Bold is described. During zoosporogenesis, the pyrenoid undergoes regression, and the ultrastructure of this process is described in detail. The ground substance undergoes dissolution, and reticulate fibrillar structures appear as well as intruding chloroplast thylakoids. Pyrenoid-associated starch plates diminish, and quantities of starch not associated with the pyrenoid are produced. New pyrenoids appear late in the division cycle after all other major organelles associated with the motile cell have been formed. Zoospore pyrenoids develop in thylakoid-free spaces of the chloroplast which are similar to the DNA-containing regions. The new pyrenoid ground substance, which is loosely fibrillar, arises in close proximity to starch grains which may be formed in the stroma. Then the zoospore pyrenoid produces 2 hemispherical starch plates identical to those in the mature vegetative cell. Zoospore pyrenoids lack the 2 convoluted thylakoids between the starch plates and the ground substance characteristic of those in the mature vegetative cell. Instead, the thylakoids are identical to those of the chloroplast at first, and then develop into a convoluted state in the vegetative cell. Cytochemical tests for DNA, RNA, and protein were made for the cytoplasm, nucleus, nucleolus, and pyrenoid. Conclusive evidence is presented for the presence of RNA in the cytoplasm and nucleolus, DNA in the nucleus, and protein in the pyrenoid. The tests did not conclusively demonstrate the presence or absence of DNA and RNA in the pyrenoid; however, they suggested that small amounts of both DNA and RNA may be present. 相似文献
9.
Comparative ultrastructural investigations on many isolates ofTetraselmis from Japan and the Pacific coast of North America, and on cultures from the Culture Centre of Algae and Protozoa, Cambridge,
England, have revealed that the species have characteristic fine structural features of the pyrenoid. Using the pyrenoid structure
as a basic character it is proposed that the genus be subdivided into four subgenera,Tetraselmis, Prasinocladia, Tetrathele andParviselmis. In the present paper, species of the subgenusTetraselmis, includingT. cordiformis, T. ascus, T. convolutae andT. astigmatica sp. nov., are described in detail. 相似文献
10.
Pinguiococcus pyrenoidosus gen. et sp. nov. (Pinguiophyceae), a new marine coccoid alga 总被引:3,自引:0,他引:3
A coccoid marine alga, collected from an aquaculture tank and maintained in culture as CCMP1144, was examined using light and electron microscopy. Young, rapidly growing cells were mostly spherical in shape, approximately 4–6 μm in diameter. Older cells often produced protrusions and pseudopodia‐like extensions, giving cells an amoeboid‐like appearance, but no amoeboid movement was observed and the pseudopodia‐like extensions exhibited no active movement. The single chloroplast had a typical photosynthetic stramenopile ultrastructure. A large stalked pyrenoid was easily observed by light microscopy. Ultrastructurally, the granular portion of the pyrenoid was divided into sections by a penetrating chloroplast envelope. A mitochondrion was often, but not always, adjacent to the pyrenoid, and in some cases the mitochondrion formed a ‘cap’ over the protruding pyrenoid. The Golgi cisternae were (when viewed in cross‐section) curved toward the nucleus. A peripheral network of anastomosing tube‐like membranes was located immediately beneath the plasmalemma. Two centrioles were located adjacent to the nuclear envelope. Lipid‐like and electron transparent vacuoles were present. Based on this investigation and data published elsewhere (large percentage of eicosapentaenoic acid, 18S rRNA and rbcL genes), this alga was described as Pinguiococcus pyrenoidosus gen. et sp. nov. 相似文献
11.
Summary The ultrastructure of the mature pyrenoid of the chaetophoracean algaLeptosiropsis torulosa is unlike any described for the green algae. The nucleus is surrounded by the pyrenoid, with only the endoplasmic reticulum interrupting the encircling pyrenoid. The pyrenoid possesses only the appressed plastid membranes that are in contact with the nucleus, with no traversing thylakoids present. 相似文献
12.
Shigetoh Miyachi Mikio Tsuzuki Isao Maruyama Miroslav Gantar Shizuko Miyachi Hisashi Matsushima 《Journal of phycology》1986,22(3):313-319
Effects of CO2 concentration during growth on intracellular structure were studied with ftve species of Chlorella and Scenedesmus obliquus. Cells grown under ordinary air conditions (low-CO2 cells) had a well developed pyrenoid surrounded by starch, while those grown under high CO2 conditions (high-CO2 cells) had a less developed pyrenoid or no detectable pyrenoid. Two mitochondria, one at each side of the neck of the projection of the chloroplast close to the pyrenoid, were found in low CO2 cells of C. vulgaris 11h. Usually, lamellar stacks extended in parallel in the chloroplast of low-CO2 cells of C. vulgaris 11h, while a grana-like structure was found in high-CO2 cells. However, in C. pyrenoidosa, grana like structures were found more commonly in low-CO2 cells than in high-CO2 cells. These results suggest that development of pyrenoid starch is generally correlated with growth under low CO2 conditions, whereas CO2-effects on lamellar stacking are species dependent. 相似文献
13.
E.G. Williams 《欧洲藻类学杂志》2013,48(3):515-518
Tetrachlorella alternans Korshikov and Paulschulzia pseudovolvox (Schulz) Skuja are described from Cheshire, England. The presence of a pyrenoid with starch is noted for Quadricoccus laevis Fott. 相似文献
14.
THE ULTRASTRUCTURE OF LICHENS. I. A GENERAL SURVEY 总被引:1,自引:0,他引:1
The fine structure of 10 lichens was examined. A comparison was made of the storage products of the algal symbiont (Trebouxia) in situ in the desiccated and hydrated states of the lichens. All the Trebouxia phycobionts, with the exception of that in Usnea strigosa, had lipid-containing globules in the pyrenoid. The globules were present in both the hydrated and desiccated conditions. Trebouxia in the hydrated condition contained starch granules in the chloroplast as well as the lipid-containing globules in the pyrenoid. The cell wall of Trebouxia consists of an outer electron-dense layer and an inner electron-light layer. Fungal haustoria (in Lecanora rubina) rupture the outer layer of the algal cell wall and invaginate the inner layer. A thick polysaccharide fibrillar material surrounds the fungal cells. Many bacteria were observed within this material. Septa and lomasomes are described. Ellipsoidal bodies, which appear to be an integral and unique part of the lichen fungal ultrastructure, were observed associated with membrane profiles. 相似文献
15.
D. L. Taylor 《Archives of microbiology》1972,81(2):136-145
Summary The ultrastructural morphology of Cocconeis diminuta, a small benthic diatom, is described. It has been found to possess a typical naviculoid organisation, and does not differ significantly from other species examined with the electron microscope. The pseudoraphe, frequently regarded as an important taxonomic criterion, has been found to be a variable feature in C. diminuta and its significance in this regard appears doubtful. Special reference is made to the substructure of the pyrenoid, since it appears to possess a crystal lattice that is similar in structure to the one described in the dinoflagellate Prorocentrum micans.Contribution no. 1445 from the Rosenstiel School of Marine and Atmospheric Science. 相似文献
16.
Heterocapsa circularisquama sp. nov. (Peridiniales, Dinophyceae): A new marine dinoflagellate causing mass mortality of bivalves in Japan 总被引:2,自引:0,他引:2
Takeo Horiguchi 《Phycological Research》1995,43(3):129-136
Heterocapsa circularisquama Horiguchi sp. nov. is described from Ago Bay, central Japan. The dinoflagellate produced large-scale red tides in the bays of central and western Japan and caused mass mortality of bivalves, notably the pearl oysters. The cell is small and is composed of a conical epitheca and a hemi-spheroidal hypothecs. The chloroplast is single and is connected to the single pyrenoid. The nucleus is elongated and is located in the left side of the cell. Thecal plate arrangement has been determined as: Po, cp, 5′, 3a, 7″, 6c, 5s, 5″′, 2″″. Heterocapsa circularisquama is morphologically very similar to Heterocapsa illdefina and it is almost impossible to distinguish these two species at light microscopical level. The characteristics which can be used to distinguish these two species are the morphology of body scales and the ultrastructure of the pyrenoid matrix. The body scales of H. circularisquama possess six radiating ridges on the circular basal plate; no such ridges can be observed on the roughly triangular basal plate of the scales of H. illdefina. Furthermore, the scales of the latter species possess substantially shorter spines compared to those of H. circularisquama. The pyrenoid matrix of H. circularisquama is hardly perforated by cytoplasmic tubules, while in H. tlldefina the pyrenoid matrix is always penetrated by many cytoplasmic tubules. Based on the arrangement of thecal plates, morphology of body scales, and ultra-structure of the pyrenoid, I am placing H. circularisquama sp nov. into the genus Heterocapsa. 相似文献
17.
A new chlorarachniophytan alga, Gymnochlora stellata Ishida et Y. Hara gen. et sp. nov., has been isolated from Anae Island in Guam. It is a green, star-shaped, unicellular, amoeboid organism with several filopodia that do not form a reticulopodial network. Neither zoospores nor walled coccoid cells have been observed throughout the life cycle. The chloroplast ultrastructure is similar to those of described species; however, the pyrenoid matrix, which is invaded by many tubular structures originating from the inner membrane of the chloroplast envelope, is unique. A classification system is proposed for the Chlorarachniophyta. In this system, the ultrastructural features of the pyrenoid and the location of the nucleomorph in the periplastidial compartment are used as generic criteria, while the morphological features of the vegetative cells and life cycle patterns are used for species criteria. The described species, except for Cryptochlora perforans Calderon-Saenz et Schnetter, are also reassessed under the new system, and consequent nomenclatural requirements for the genus Chlorarachnion are dealt with in this paper. The taxonomic rank of a previously described species, Chlorarachnion globosum Ishida et Y. Hara, is elevated and Lotharella globosa (Ishida et Y. Hara) Ishida et Y. Hara gen. nov. et comb. nov. is proposed. 相似文献
18.
19.
Shoichiro Suda 《Journal of phycology》2003,39(3):590-599
Nephroselmis spinosa Suda sp. nov. is described based on LM and EM observations. Two strains of N. spinosa (S222 and SD959‐3) were isolated from sand samples collected from the northwest coast of western Australia. The cells were remarkably right–left flattened and appeared ellipse or bean‐shaped when viewed from their right or left side. A single, parietal, crescent chloroplast was pale green to yellowish green and contained one conspicuous eyespot in its anterior ventral edge near the base of the short flagellum. A pyrenoid with three starch plates was located at the dorsal of the chloroplast. The cells divided by transverse binary cell division, as is common in other species of this genus. This alga possessed four types of body scales, and three scale types were similar to N. olivacea Stein and N. astigmatica Inouye & Pienaar. However, the fourth and outermost scale type was distinctive because although it was a spiny stellate scale with nine spines, one of them extended about 1 μm and was slightly curved with a hook at the end. This scale morphology, an important taxonomic characteristic, has never been described for the genus Nephroselmis. The cell's morphology, pyrenoid structure, hair scales, and cell size were distinctive from previously described Nephroselmis species, and its unique scale characteristic led me to name this newly proposed species “spinosa,” meaning spiny. 相似文献
20.
Ryan W. Drum 《The Journal of cell biology》1963,18(2):429-440
The cytoplasmic fine structure of the motile, pennate diatom, Nitzschia palea was studied in thin sections viewed in the electron microscope. The cells were fixed in OsO4, embedded in methacrylate, and immersed in 10 per cent hydrofluoric acid (HF) for 36 to 40 hours to remove the siliceous cell wall prior to sectioning. The HF treatment did not cause any obvious cytoplasmic damage. The dictyosome complex is perinuclear, and located only in the central cytoplasm. Mitochondria are sparse in the central cytoplasm, but abundant in the peripheral cytoplasm, and fill many of the transvacuolar cytoplasmic strands. Characteristic, amorphous oil bodies fill certain cytoplasmic strands and probably are not leucosin. The pyrenoid appears to be membrane limited, and oil droplets are found adjacent to the pyrenoid. The pyrenoid of another diatom, Cymbella affinis, is also membrane-limited. The membrane limiting the pyrenoid may be a composite of the terminal portions of chloroplast discs, facilitating rapid movement of photosynthate into the pyrenoid matrix, where the characteristic oil droplets may be formed. Carinal fibrils are found singly in each carinal pore, and may be involved in the locomotion of Nitzschia palea. 相似文献