Descriptor: "Xanthophyta" - Searchworks@Jio Institute Digital Library Search Results

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19 results on '"Xanthophyta"'

1. Mitosis, cytokinesis and multinuclearity in a Xanthonema (Xanthophyta) isolated from Antarctica.

Author: Massalski, Andrzej, Kostikov, Igor, Olech, Maria, and Hoffmann, Lucien
Subjects: *MITOSIS, *CYTOKINESIS, *XANTHOPHYCEAE, *CHLOROPLASTS, *MITOCHONDRIA
Abstract: The ultrastructure of a Xanthonema strain featuring multinucleate cells was investigated by transmission electron microscopy. An important specific feature of the organisation of the photosynthetic apparatus in this strain is its association with mitochondrial profiles. The chloroplast girdle is composed of two different U-shaped lamellae, one peripheral and one subcentral. Multinuclearity is observed as often as the uninucleate state. The transition from the uninucleate to the multinucleate stage is connected to disturbances in the normal division pattern of the parietal chloroplast-mitochondria complex during interphase. As a result mitosis is not coordinated with cytokinesis. The return to the uninucleate stage occurs as a result of asynchronous cytokinesis or by aplanospore formation. Mitosis is of the semi-closed type, as in Tribonema. Centrioles replicate in early interphase, after the end of karyokinesis and progeny nuclei separate with the aid of CER invagination. Filament fragmentation takes place between neighbouring cells where two U-shaped segments adjoin, resulting in fragment ends being rounded rather than 'zweispitzig'. The taxonomic significance of various ultrastructural features for the classification of filamentous Xanthophyta is discussed. [ABSTRACT FROM AUTHOR]
Published: 2009
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2. Use of a deviant mitochondrial genetic code in yellow-green algae as a landmark for segregating members within the phylum.

Author: Ehara, Megumi, Hayashi-Ishimaru, Yasuko, Inagaki, Yuji, and Ohama, Takeshi
Abstract: Several algae that were previously classified in the phylum Xanthophyta (yellow-green algae) were assigned in 1971 to a new phylum, Eustigmatophyta. It was anticipated that the number of algae reclassified to Eustigmatophyta would increase. However, due to the fact that the morphological characteristics that segregate eustigmatophytes from other closely related algae can be only obtained through laborious electron microscopic techniques, the number of members in this phylum have increased rather slowly. We attempted, therefore, to segregate two closely related groups of algae, eustigmatophytes and yellow-green algae, on the basis of a molecular phylogenetic tree as a means of providing an alternative method of distinguishing these phyla. We analyzed the mitochondrial cyto-chrome oxidase subunit I ( COXI) gene sequences of eight algae classified as xanthophyceans and found that six manifested the expected deviant genetic code where AUA codes for methionine (AUA/Met), but not for isoleucine (AUA/Ile) as in the universal genetic code. The other two, Monodus sp. (CCMP 505) and Ophiocytium majus (CCAP 855/1), which were presumed to be yellow-green algae, and all the examined eustigmatophytes utilized AUA for Ile. In addition, the phylogenetic tree of COXI gene sequences showed that the six yellow-green algae bearing the AUA/Met deviant code composed a tight clade with a bootstrap value of 100%. The phylogenetic tree of the corresponding sequences from Monodus sp. and Ophiocytium majus and the eustigmatophytes also composed a tight cluster, but with a bootstrap value of 92%. These results strongly suggest that two previously classified members of yellow-green algae belong to the phylum Eustigmatophyta. Therefore, examination of the mitochondrial genetic code in algae appears to be a potentially very useful genetic marker for classifying these organisms, especially when it is considered with the results obtained through a molecular phylogenetic tree. [ABSTRACT FROM AUTHOR]
Published: 1997
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3. Blue light promotes ionic current influx at the growing apex of Vaucheria terrestris.

Author: Kataoka, Hironao and Weisenseel, Manfred
Abstract: Irradiation of the growing apex of the alga Vaucheria terrestris Götz var. terrestris with blue light (BL), which causes a transient acceleration of growth, also causes a large transient increase in inwardly directed current, which was monitored with a vibrating probe. The growing apex is normally the site of an inward current, and the surface of the non-growing, basal part of the coenocytic cell the site of an outward current. Irradiation of the apex causes only a slight increase in current efflux at the basal part of the cell. The BL-promoted current influx at the apex (BLCI) usually starts within 10 s after the onset of irradiation, preceding the light-growth response. With BL pulses shorter than 3 min, the BLCI reaches a maximum in about 3 min, and then declines to its original value over the next 3 min. If the BL pulse is longer than 3 min, the BLCI continues until the light is turned off. The threshold energy of the BLCI with broad-band BL is 2-5 J·m, i.e. smaller than for both the light-growth response and phototropic response. The maximum BLCI reaches a value of approx. 5 μA·cm, equivalent to an influx of 50 pmol·cm·s of monovalent cations. The effect of red light (RL) is completely different from that of BL: it either causes increases in the inward current of less than 0.3 μA·cm, or a transient decrease of current. Furthermore, the direction of the RL-induced change is always the same at the apex and trunk, indicating the participation of photosynthesis. Our results indicate that the BLCI is kinetically and spatially related to the light-growth response and the phototropic bending of Vaucheria. It seems to be a necessary step for the phototropic bending. [ABSTRACT FROM AUTHOR]
Published: 1988
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4. The action spectrum for chloroplast movements and evidence for blue-light-photoreceptor cycling in the alga Vaucheria.

Author: Blatt, Michael
Abstract: Local stimulation of the coenocytic alga Vaucheria sessilis D.C. by blue light resulted in accumulation of chloroplasts and other organelles. The photoresponse followed a well-defined, wavelength-and fluence-rate-dependent latency period (≧10 s), and could lead to a tenfold decrease in relative cellular transmittance to 675-nm light within 5 min. Light-induced aggregation of chloroplasts was examined at eight wavelengths of light between 385 and 528 nm. A fiber-optic microphotometer was employed and the response was quantitated on the basis of the rate of 675-nm transmittance change after correcting for changes in light scattering. Chloroplast aggregation exhibited a nearly identical quantum-flux-density dependence at all eight wavelenths tested; it showed an action spectrum with a sharp maximum near 470 nm, a trough at 430 nm, and action in the near-ultraviolet spectral region. Light at 454 nm was six times less effective than 473-nm light in stimulating aggregation, a difference which could not be accounted for by chlorophyll screening alone. Beyond the latency period reciprocity did not hold for chloroplast aggregation. Instead, aggregation could be fitted to a kinetic model involving steady-state photoreceptor cycling during continuous irradiation. Chloroplast aggregation in the light was compared with three growth-associated photoresponses in Vaucheria - phototropic bending, branching and apical expansion. Time course and kinetic similarities, and the presence of a cytoplasmic fiber network in growing tips of Vaucheria, indicate that these photoresponses may be related mechanistically. [ABSTRACT FROM AUTHOR]
Published: 1983
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5. DYNAMICS OF ALGAE NUMBER AND BIOMASS OF STEPPE BIOGEOCOENOSES AND AGROCOENOSES IN KHERSON REGION

Author: Shcherbina V.V.
Subjects: steppe biogeocoenosis, lcsh:Biology (General), Chlorophyta, Eustigmatophyta, agrocoenosis, Cyanophyta, Xanthophyta, Bacillariophyta, lcsh:QH301-705.5, seaweeds abundance and biomass
Abstract: Characteristics of daily dynamics of seaweeds abundance and biomass were determined for steppe biogeocoenosis and agrocoenosis of Biosphere reserve “Askaniya-Nova” in spring of 2011. Fluctuation ranges in seaweeds abundance and biomass have been registered.Analyzing the indices of total number and algae biomass in studied biogeocoenoses it should be noted that the maximal values of alga number in virgin soil steppe exceeded minimal in 3,3 times; biomasses - in 2,1. For virgin soil steppe of post-fire-induced development the relation between maximum and minimal value of total number of algae was up to 2,1; biomass - 2,4. For agrocoenosis we noted the largest ranges in variation of number and biomass. In conditions of dry-land arable land the maximum values of total number of alga exceeded minimal in 21,9 times; biomasses - in 8,7; for irrigated arable land - in 12,5 and 5,6 respectively.In soil samples, selected within the limits of virgin soil biogeocoenoses of biosphere reserve “Askania-Nova” and agrocoenosis of dry-land and irrigated arable land in biosphere reserve by direct count, the algae species of Bacillariophyta, Cyanophyta, Chlorophyta, Xanthophyta and Eustigmatophyta have been found. The largest contribution to number and biomass of algae belonged to Bacillariophyta. The number and biomass of agrocoenosis algae is more dynamic feature, than for algae of virgin soil biogeocoenoses.
Published: 2011

6. The survey of Khandaghloo dam reservoir of Mahneshan city of Zanjan province

Author: Abdolmalaki, Shahram, Mirzajani, A.R., Khodaparast, S.H., Saberi, H., Babaei, H., Sabkara, J., Makaremi, M., Norouzi, H., Nahrvar, R., Khedmati, K., Nikpour, M., Rastin, R., Behmanesh, Sh., Ghane, A., Mehdizadeh, Gh., Mahisefat, F., Mohsenpor, H., Sayadrahim, M., Shondasht, J., Madadi, F., Sedaghatkish, A., Khoshhal, J., Iranpor, M., and Rohbani, Sh.
Subjects: Parichay river, Ecology, Silver Carp, Euglenophyta, Pyrrophyta, Xanthophyta, Iran, Fish production potential, Khandaghloo dam reservoir, Zooplankton, Common carp, Grass carp, Trophy, Chlorophyta, Phytoplankton, Zanjan province, Benthose, Mahneshan, Cyanophyta, Green algae, Crayfish Fish, Bacillariophyta
Abstract: Reservoirs are one of the most constructions for control and water supply for different usage that could have various social an economical effects. The Khandaghloo dam reservoir with area of 100 ha located in Mahneshan city of Zanjan province and related to Parichay river watershed. Khandaghloo reservoir is valuable water body that the aim of its establishment was supply of water for agriculture farms. The reservoir has been studied for responsible and sustainable fisheries exploitation proposes. Results showed that the reservoir categorizes as eutroph to super eutroph based on different indices.Also phosphorous is limiting factor of the water body.Totally 42 genera from 6 phyla including green-blue algae cyanophyta, diatoms (Bacillariophyta), green algae, chlorophyta, euglenophyta, pyrrophyta and xanthophyta has been identified and cyanophyta was the dominant group that comprise 74.3 % of phytoplankton population. The zooplankton of the reservoir comprised 4 phyla and 20 genera. 1 genera of the protozoa and rhizopoda, 1 genra of the ciliophora ,15 genera of rotatoria, 2 genera of cladocera has been identified in zooplankton communities. Tubificidae and chironomidae has been identified in all months of the survey. The mean total length of crayfish was 130.5±20.5 mm ( 636) and mean weight was measured as 69.4±34.1 g with maximum and minimum weight of 1.9 and 207.2 g respectively .Total biomass of crayfish in Khandaghloo reservoir estimated as 3.4 tones with a range of 1.1–5.7 tones. But it is recommended not to harvest for at least two year due to high mortality of the populations.The fishes of the reservoir comprised common carp Chinese carp (silver carp, big head and grass carp) (released), Caspian kutum (accidentally released by fishery sector) and some endemic species as Siamahii. The catch of the reservoir fluctuated between 8 to 26 tones during 2000-2010.The fish production of Khandaghloo reservoir ranged from 167 to 324 kg/ha based on different methods that by consideration of 100 ha area of the reservoir, the total production of fish fluctuated between 16.7 to 32.4 tones. The fingerling restocking of Chinese carp in Khandaghloo reservoir with density of 1500 fingerling/ha recommended as 68% of phytoplanktonivorous fish (silver carp) ,12% zooplanktonivorous fish (big head), 6.6% of Crass carp and 10% of benthophagous fish (common carp).
Published: 2015

7. Vaucheria canalicularis T. A. Chr

Author: Jarvis, Charlie
Subjects: Vaucheriales, Vaucheria canalicularis, Xanthophyceae, Biodiversity, Xanthophyta, Vaucheriaceae, Plantae, Taxonomy, Vaucheria
Abstract: Conferva canalicularis Linnaeus, Species Plantarum 2: 1164. 1753. "Habitat in Europae rivulis, tubulis, canalibus molendinariis." RCN: 8378. Lectotype (Christensen in Brit. Phycol. Bull. 3: 466. 1968): [icon] " Conferva rivulorum capillacea, densissime congestis ramulis " in Dillenius, Hist. Musc.: 21, t. 4, f. 15. 1741. - Voucher: Herb. Dillenius (OXF). Current name: Vaucheria canalicularis (L.) T.A. Chr. (Vaucheriaceae). Note: Van den Hoek (Revis. Eur. Sp. Cladophora: 223. 1963) designated material in the Dillenius herbarium as the type but as this was not studied by Linnaeus, it cannot be original material. Christensen (in Brit. Phycol. Bull. 3: 465-466. 1968) treated Dillenius’ description as the type but clearly included the cited plate as part of this. As a consequence, his statement is accepted as a formal typification of the name., Published as part of Jarvis, Charlie, 2007, Chapter 7: Linnaean Plant Names and their Types (part C), pp. 370-473 in Order out of Chaos. Linnaean Plant Types and their Types, London :Linnaean Society of London in association with the Natural History Museum on page 435, DOI: 10.5281/zenodo.291971
Published: 2007
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8. Vaucheria

Author: Jarvis, Charlie
Subjects: Vaucheriales, Xanthophyceae, Biodiversity, Xanthophyta, Vaucheriaceae, Plantae, Taxonomy, Vaucheria
Abstract: Conferva amphibia Linnaeus, Species Plantarum 2: 1164. 1753. "Habitat in Europae udis, fossis, umbrosis, ubi aquae vicissitudines servant." RCN: 8379. Type not designated. Original material: [icon] in Dillenius, Hist. Musc.: 22, t. 4, f. 17. 1741. Current name: Vaucheria sp. (Vaucheriaceae). Note: For a discussion of the difficulties associated with this name, see Christensen (in Brit. Phycol. Bull. 3: 466-467. 1968), who treated it as a " species minus cognita ". The name may threaten Vaucheria dillwynii (F. Weber & Mohr) C. Agardh and may be a candidate for rejection.
Published: 2007
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9. Vaucheria fontinalis T. A. Chr

Author: Jarvis, Charlie
Subjects: Vaucheria fontinalis, Vaucheriales, Xanthophyceae, Biodiversity, Xanthophyta, Vaucheriaceae, Plantae, Taxonomy, Vaucheria
Abstract: Conferva fontinalis Linnaeus, Species Plantarum 2: 1164. 1753. "Habitat in Europae fontibus." RCN: 8376. Lectotype (Christensen in Brit. Phycol. Bull. 3: 465, f. 1-4. 1968): [icon] " Conferva minima Byssi facie " in Dillenius, Hist. Musc.: 14, t. 2, f. 3. 1741. - Voucher: Herb. Dillenius (OXF). Current name: Vaucheria fontinalis (L.) T.A. Chr. (Vaucheriaceae). Note: Christensen (in Brit. Phycol. Bull. 3: 465. 1968) treated Dillenius’ description as the type but clearly included the cited plate as part of this. As a consequence, his statement is accepted as a formal typification for the name., Published as part of Jarvis, Charlie, 2007, Chapter 7: Linnaean Plant Names and their Types (part C), pp. 370-473 in Order out of Chaos. Linnaean Plant Types and their Types, London :Linnaean Society of London in association with the Natural History Museum on page 435, DOI: 10.5281/zenodo.291971
Published: 2007
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10. Vaucheria dichotoma Mart

Author: Jarvis, Charlie
Subjects: Vaucheriales, Xanthophyceae, Vaucheria dichotoma, Biodiversity, Xanthophyta, Vaucheriaceae, Plantae, Taxonomy, Vaucheria
Abstract: Conferva dichotoma Linnaeus, Species Plantarum 2: 1165. 1753. "Habitat in Angliae fossis pratorum." RCN: 8382. Lectotype (Christensen, Seaweeds Brit. Isles 4: 15. 1987): [icon] " Conferva dichotoma, setis porcinis similis " in Dillenius, Hist. Musc.: 17, t. 3, f. 9. 1741. - Voucher: Herb. Dillenius (OXF). Current name: Vaucheria dichotoma (L.) Mart. (Vaucheriaceae). Note: See Christensen (in Brit. Phycol. Bull. 3: 465. 1968), who discussed Dillenius’ description, figures and voucher material in OXF (the latter reproduced as f. 5, 6), stating (p. 463) that the Dillenian material was the type. This, however, was not seen by Linnaeus and is not original material for the name. Christensen (in Brit. Phycol. J. 21: 275. 1986) subsequently treated Linnaeus’ description as the type but this is contrary to Art. 8.1., Published as part of Jarvis, Charlie, 2007, Chapter 7: Linnaean Plant Names and their Types (part C), pp. 370-473 in Order out of Chaos. Linnaean Plant Types and their Types, London :Linnaean Society of London in association with the Natural History Museum on page 435, DOI: 10.5281/zenodo.291971
Published: 2007
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11. The plankton of the Anzali Lagoon and coastal waters of the Caspian Sea

Author: Makaremi, Marzia, Sabkoara, Jilil, Mohammadjani, T., Fallahi, M., and Oladrabie, H.
Subjects: Species, Diatoms, Phylum, Ecology, Arthropoda, Population, Euglenophyta, Density, Xanthophyta, Iran, Bivalvia, Copepoda, Mollusca, Rhodophyta, Caspian Sea, Planktons, Cyanophyta, Bacillariophyta, Protozoa, Biology, Chrysophyta, Anzali lagoon
Abstract: The determination and identification of plankton species in the Anzali lagoon was carried out through a period of two years in 27 stations in the Shejan, Sakishima, Abkenar, Hendekhaleh andmain outlets of this lagoon from 1997 to 1999. The results of this study reveal that there are Totally 6 phyla of Phytoplankton that include, 134genera and 278 species of which 56 genera and 107 species belong to Phylum Chlorophyta, 39 genera and 87 species belong to Phylum Bacillariophyta (Diatoms), 2 genera and 2 species belong to Phylum Xanthophyta, 4 genera and 4 species belong to Phylum Chrysophyta, 6 genera and 34 species belong to Phylum Euglenophyta, 8 genera and 11 species belong to Phylum Pyrrophyta, 18 genera and 32 species belong to Cyanophyta and one genus belongs to phylum Rhodophyta. It is evident from these results that Cyanophyta and Bacillariophyta showed the highest density among Phytoplanktons with the highest Aboundance found in the Abkenar and southern Hendekhalehregions. Highest density of Cyanophyta was observed in Abkenar region during the end of spring and beginnings of summer. Bacillariophyta was observed all-round the year throughout the Anzali lagoon being more aboundant the end of autumn, winter and spring. Other phyla showed similar population densities throughout the year. study of Zooplanktons revealed the presence 11 phylum that include 133 genera and 211 species Anzali lagoon of which 10 genera 22 species belong to phylum Rhizopoda ,4 genera 4 species belongto Phylum Actinopoda, 32 genera 41 species belong to Phylum Ciliophora, one genus and one specie belong to Phylum Porifera, 3 genera belong to Phylum Coelantrata, 2 genera and 2 species belong toAnnelida, 2 genera 2 species belong to Phylum Platyhelminthes, 36 genera and 90 species belong toPhylum Rotatoria, one genus and one specie belongs to Phylum Tardigrada, 19 genera and 32 species belong to Phylum Arthropoda (order Cladocera), 7 genera and 11 Species belong to Class Copepoda, in Class Cirripedia and Ostracoda and Diptera(Family Chironomidae) each of them consisting of onegenus, 2 genera and 2 species belong to Class Archnida and in phylum Mollusca Class Bivalvia one genus was identified. It is evident from the present study that Rotrtoria was dominant in southern Hendekhaleh and Abkenar regions and the main outlets wherease Protozoa showed the maximum density in Shejan and Siakishem regions. Highest density of Zooplankton were observed in Hendekhaleh and Abkenar regions in end of Spring and during summer whereas all regions showed similar densities during the other seasons .
Published: 2007