Genus Coscinodiscus Research Articles

Struktur Komunitas Fitoplankton di Perairan Teluk Benoa, Bali

Benoa Bay is a waters that have tourism activities, ship transportation routes and aquaculture. The reasearch of phytoplankton community structure conducted in February 2019. Phytoplankton sampling carried out horizontally by pulling the plankton net using a ship for 5 minutes. The plankton net used has a 30 µm meshsize, 50 cm in diameter and 1.5 meters in length. The composition of phytoplankton species consisted of Bacillariophyceae and Dinophyceae classes. The total abundance of phytoplankton individuals ranged from 268.07 sel/l to 2,500.59 sel/l with an average value 878.87 sel/l. The value range of phytoplankton diversity index was 0,31 to 1,47, with an average value is 0.87. This shows that in general the phytoplankton community has low diversity (H'<1). The phytoplankton uniformity index ranged from 0,14 - 0,58, with an average value is 0,35. This shows that in general the phytoplankton community has low uniformity (E<0.4). The value range of dominance index was 0,31 to 0,89, with an average value is 0.63. This shows that in general the dominance value is high (1>C>0.5). Relatively low uniformity values with relatively high dominance values indicate that the genus found during the study has a non-uniform composition and there is a dominating genus, namely the genus Coscinodiscus from the Bacillariophyceae class.

Complete mitochondrial genome of Coscinodiscus granii (Coscinodiscophyceae, Bacillariophyta)

Coscinodiscus is a genus common in marine phytoplankton, with some species thought to have a significant negative ecological impact. However, the availability of their genome sequences is rather limited. Here, we assembled and annotated the first complete mitochondrial genome (mtDNA) of the species Coscinodiscus granii L.F.Gough 1905, as part of our efforts to gain a better understanding of the genetic characteristics of Coscinodiscus taxa at a genomic level. The circular mtDNA was 34,970 bp in length and encoded 60 genes, including 32 protein-coding genes (PCGs), 24 transfer RNA (tRNA) genes, two ribosomal RNA (rRNA) genes, and two conserved open reading frames (orfs). The overall GC content of C. granii mtDNA was 24.30%, which was slightly lower than that of C. wailesii (25.00%), the first species in the genus Coscinodiscus whose mtDNA has been reported, and higher than that of Melosira undulata (21.60%), the first species in the class Coscinodiscophyceae whose mtDNA has been reported. As expected for congeneric species, phylogenetic analysis using concatenated amino acid sequences of 27 shared PCGs suggested that C. granii has a closer evolutionary relationship with C. wailesii. Coscinodiscus was found to be monophyletic in the phylogeny. The complete mtDNAs of more Coscinodiscus species will facilitate the exploration of the evolutionary relationships of species in the Class Coscinodiscophyceae.

The complete mitochondrial genome and phylogenetic analysis of Coscinodiscus wailesii (Coscinodiscophyceae, Bacillariophyta)

Coscinodiscus is a species-rich genus with about 400 species described, many of which are harmful algal bloom species with significant negative ecological impact. Despite of their importance in primary production and as harmful algal bloom species, genome data for species in this genus is limited. No mitochondrial genome (mtDNA) of any species in this genus has been reported. Here, the complete mtDNA sequence of the Coscinodiscus wailesii Gran & Angst 1931 was constructed and analyzed. The circular mtDNA was 36,071 bp in length, encoding 64 genes, including 34 protein coding genes (PCGs), 24 transfer RNA (tRNA) genes, 2 ribosomal RNA (rRNA) genes and 4 conserved open reading frames (orfs). The overall AT content of C. wailesii mtDNA was 75.00%, which was slightly lower than that of Melosira undulate (78.40%). Maximum likelihood (ML) phylogenetic analysis using 29 shared protein-coding genes revealed that C. wailesii clustered well with M. undulata, which was the only species of class Coscinodiscophyceae whose mtDNA has been fully constructed. The complete mtDNAs of more Coscinodiscus species will be valuable for studying the evolutionary relationships among species in the genus Coscinodiscus and in the Class of Coscinodiscophyceae.

Dual culture of the oomycete Lagenisma coscinodisci Drebes and Coscinodiscus diatoms as a model for plankton/parasite interactions

Diatoms are thought to provide about 40% of total global photosynthesis and diatoms of the genus Coscinodiscus are an important, sometimes dominant, cosmopolitan component of the marine diatom community. The oomycete parasitoid Lagenisma coscinodisci is widespread in the northern hemisphere on its hosts in the genus Coscinodiscus. Because of its potential ecological importance, it would be a suitable pathogen model to investigate plankton/parasite interactions, but the species cannot be cultivated on media without its host, so far. Thus, it was the aim of this study to explore the potential of dual culture of host and pathogen in the laboratory and to optimise cultivation to ensure a long-term cultivation of the pathogen. Here, we report successful cultivation of a single spore strain of L. coscinodisci (Isla), on several Coscinodiscus species and strains, as well as the establishment of a cultivation routine with Coscinodiscus granii (CGS1 and CG36), which enabled us to maintain the single spore strain for more than 3 years in 6 cm Petri dishes and 10 ml tissue culture flasks. This opens up the opportunity to study the processes and mechanism in plankton/parasitoid interactions under controlled conditions.

Identification and Monitoring of Microalgal Genera Potentially Capable of Forming Harmful Algal Blooms in Punta Galeta, Panama

Coastal areas are attractive for human settlements because they allow easy access to benefits like food, security, and fishing. These aquatic ecosystems are supported by photosynthetic organisms that constitute the base of the food web. The term “Harmful Algal Bloom” (HAB) refers to the excessive proliferation of some taxa of these microorganisms reaching harmful levels to humans and other organisms. Biotoxins produced by these HABs could be transferred to the food chain and are the best-documented impact that HABs have on humans. The location and abundance of the HAB species producing the toxin is a good indicator of a possible human health hazard. The aim of this study was to monitor potentially harmful benthic/epibenthic microalgae in Punta Galeta, Panama over a 15-month period. The 3 main microalgae found were 2 dinoflagellates from the genera Prorocentrum and Ostreopsis and 1 diatom from the genus Coscinodiscus. Sampling made with both natural and artificial substrates yielded similar overall abundance patterns; however, for the macroalgae samples, there appeared to be significant host preferences for Ostreopsis and Coscinodiscus. Physicochemical measures taken at the site were found to fall within previously reported growth parameters for the microalgae found in the study.

Pengaruh Konsentrasi Nutrien Terhadap Kelimpahan Fitoplankton di Perairan Halmahera-Maluku

<strong>Effects of Nutrients Concentration on Phytoplankton Abundance in The Halmahera-Molucca Sea.</strong> The availability of nutrients in the ocean is essential for the growth and accumulation of phytoplankton biomass. The input nutrients can then changes its ratio which may affect the species composition of phytoplankton communities and higher trophic level biotas. The effects of nutrients on phytoplankton abundance are very important to be studied due to its role as limiting factors for phytoplankton growth. Besides that, these two variables are most important factors in measuring aquatic productivity. This study aims to analyzed composition and abundance of phytoplankton and its relationship with dissolved inorganic nutrients in the Halmahera-Molucca Sea. This research was conducted in November 2015 covering 8 sampling station within the Halmahera-Molucca Sea. Water quality parameters, such as pH was measured using potentiometic method, dissolved oxygen (DO was measured using titrimetric method), and nitrate, nitrite, ammonium, phosphate and silicate, were measured using the colorimetric method. The water samples were taken using Rosette sampler and then filtered using hand net plankton with size 20 μm to obtain the phytoplankton. Plankton composition and abundance were then determined by microscopic analysis. The result showed that ammonium positively correlated with phytoplankton abundance (r=0.9133 at p<0.01). The correlation between nutrients and phytoplankton show that each genus has a preference for different nutrients. The presence of ammonium significantly increase the phytoplankton abundance from genus <em>Chaetoceros, Nitzchia, Climacodium, Ceratium, Eucampia, Lauderia, Protoperidinium</em>, and <em>Rhizosolenia</em>. On the other hand, phosphates increase the phytoplankton abundance from genus Coscinodiscus although not significantly. Besides, silicates increase the phytoplankton abundance from genus <em>Thalassiothrix, Bacteriastrum, Skletonema</em>, and <em>Hemiaulus</em> while nitrates increase the phytoplankton abundance from genus <em>Alexandrium</em>.

The diatom parasite Lagenisma coscinodisci (Lagenismatales, Oomycota) is an early diverging lineage of the Saprolegniomycetes

Diatom pathogens are potentially of great ecological importance as they might play a role in the breakdown of plankton blooms. Even though several diatom-infecting oomycetes have been described, none of them has so far been included in molecular phylogenetic investigations. One of the most enigmatic species of these pathogens is Lagenisma coscinodisci, which infects centric diatoms of the genus Coscinodiscus. Its life-cycle and assumed mode of sexual recombination suggested a basal position for this pathogen. In the current study, the phylogeny of this pathogen was investigated using SSU and cox2 sequences. Phylogenetic reconstructions revealed a position basal in Saprolegniomycetes, together with Atkinsiella, while Olpidiopsis and other marine holocarpic pathogens were in an even more basal position. As the formation of oospores has been reported in Peronosporomycetes and Saprolegniomycetes, as well as in some Olpidiopsis species, the unique mode of sexual reproduction observed in Lagenisma either represents an alternative way of exchanging genetic material, rather than representing an ancestral state or suggests that oospores have evolved several times independently from resting zygotes.

Silica Pattern Formation in Diatoms: Species‐Specific Polyamine Biosynthesis

Diatoms are eukaryotic, unicellular algae that are well known for the intricate architecture of their silica-based cell walls. Species identification is mainly based on variations of their hierarchically organized silica structures. Particularly striking silica frameworks are found among diatoms that belong to the genus Coscinodiscus. Recent work indicates an important role for long-chain polyamines in guiding silica precipitation as well as in silica-pattern formation. Here we demonstrate that polyamines, even if isolated from closely related diatom species, exhibit substantial structural differences. Structural variations include the overall chain length, the degree of methylation, positions of secondary amino functionalities, and, unexpectedly, site-specific incorporation of a quaternary ammonium functionality. These findings support a specific role for polyamines in creating silica nanostructures.

A phase separation model for the nanopatterning of diatom biosilica.

Diatoms are encased in an intricately patterned wall that consists of amorphous silica. Species-specific fabrication of this ornate biomineral enables taxonomists to identify thousands of diatom species. The molecular mechanisms that control this nanofabrication and generate the diversity of patterns is not well understood. A simple model is described, in which repeated phase separation events during wall biogenesis are assumed to produce self-similar silica patterns in smaller and smaller scales. On the basis of this single assumption, the apparently complex patterns found in the valves of the diatom genus Coscinodiscus can be predicted. Microscopic analysis of valves in statu nascendi from three different Coscinodiscus species supports the conclusions derived from the model.

Pirsonia, phagotrophic nanoflagellates incertae sedis, feeding on marine diatoms: attachment, fine structure and taxonomy

Summary After being chemotactically attracted by its host, marine diatoms of the genus Coscinodiscus, the Pirsonia flagellates are guided by the topography of the host cell surface to the rimoportulae through which the trophosome, a basally formed pseudopodium, penetrates into the diatom. Cytochalasin D does not disturb the chemotaxis of the flagellates but inhibits their attachment. Pirsonia diadema and P. guinardiae, feeding on Coscinodiscus and on Guinardia flaccida, respectively, are very similar in their fine structure. The anterior flagellum has tubular hairs which seem to belong to the tripartite, stramenopile type. They are synthesized within the ER and exocytosed by the Golgi apparatus. In certain developmental stages the posterior flagellum and the cell body bear „knotted hairs“ which differ in length. The mode of their formation is unknown. The mitochondria have unique non-contorted tubular cristae which are parallel to each other. The few dictyosomes have a parabasal position. The flagellar root apparatus consists of fibrillar bands which connect the basal body of the anterior flagellum with the nucleus and with the basal body of the posterior flagellum. Other fibrillar bands and a few microtubules run from the basal bodies to the cell surface. The organization of the flagellar root apparatus thus differs from that of typical stramenopiles. The taxonomic position of Pirsonia is discussed.

Unusual diatom off the coast of south-west England and its effect on fishing

AN unfamiliar diatom was observed in the local townettings taken by research vessels of the Plymouth Laboratory towards the end of January 1977. It was a large member of the genus Coscinodiscus, but a species not previously known in the English Channel. The mucilage produced by this diatom was so abundant as to restrict trawling in some areas off Plymouth.

Studies on the Genus Coscinodiscus. III. Light, Transmission and Scanning Electron Microscopy of C granii Gough

Article Studies on the Genus Coscinodiscus. III. Light, Transmission and Scanning Electron Microscopy of C granii Gough was published on January 1, 1975 in the journal Botanica Marina (volume 18, issue 1).

Studies on the Genus Coscinodiscus. I.. Light, Transmission and Scanning Electron Microscopy of C. concinnus Wm. Smith

Article Studies on the Genus Coscinodiscus. I.. Light, Transmission and Scanning Electron Microscopy of C. concinnus Wm. Smith was published on January 1, 1975 in the journal Botanica Marina (volume 18, issue 1).

Studies on the Genus Coscinodiscus, II. Light, Transmission and Scanning Electron Microscopy of C. asteromphalus Ehr.

Article Studies on the Genus Coscinodiscus, II. Light, Transmission and Scanning Electron Microscopy of C. asteromphalus Ehr. was published on January 1, 1975 in the journal Botanica Marina (volume 18, issue 1).

AUXOSPORE FORMATION IN TWO MARINE CLONES OF THE DIATOM GENUS COSCINODISCUS

Auxospore formation has been observed in two marine clones of the diatom genus Coscinodiscus. In each of these clones the variation in valve morphology and structure before and after auxospore formation is appreciable. This variability suggests a reappraisal of the taxonomic characters within the genus will be required if the kinds and types of variation noted are substantiated in other clones. The clones are monecious and the 32 uniflagellate colorless monads, inferred from indirect evidence to be male gametes, form within an undifferentiated mother cell. The method of release of the male gametes differs in the two clones; otherwise their development is similar. The zygote is recognizable and the formation of large diameter cells within the zygote membranes has been observed.

Auxospore Formation in Two Marine Clones of the Diatom Genus Coscinodiscus

Auxospore Formation in Two Marine Clones of the Diatom Genus Coscinodiscus

A Revision of the Genus Coscinodiscus and some Allied Genera

The present paper is a continuation of my monographs already published by the Royal Microscopical Society, London, in their Journals for June and December 1888. It has been carried out under similar conditions in the Botanical Department of the British Museum (Natural History), South Kensington, but I am especially indebted to Edmund Grove, Esq., F.R.M.S., for much valuable cooperation, and to Julien Deby, Esq., for the readiness with which he has placed at my command the resources alike of his library and cabinet. Herr E. Weissflog and Dr James Rae, R.N., have also furnished me with many excellent preparations.