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39-429: See text Thalassiosira is a genus of centric diatoms, comprising over 100 marine and freshwater species. It is a diverse group of photosynthetic eukaryotes that make up a vital part of marine and freshwater ecosystems, in which they are key primary producers and essential for carbon cycling Thalassiosira is a diverse genus, however one species within the genus, T. pseudonana , has gained particular significance as

78-535: A cause, who composed The Causes , Callimachus. Ancient sources describe Callimachus's poem Ibis — which does not survive — as a polemic and some of them identified Apollonius as the target. These references conjure up images of a sensational literary feud between the two figures. Such a feud is consistent with what we know of Callimachus's taste for scholarly controversy and it might even explain why Apollonius departed for Rhodes. Thus there arises "a romantic vision of scholarly warfare in which Apollonius

117-563: A feud between Callimachus and Apollonius. The evidence partly rests on an elegiac epigram in the Palatine Anthology , attributed to "Apollonius the grammarian". It blames Callimachus for some unstated offense and mocks both him and his most famous poem, the Aetia (" Causes "): Καλλίμαχος, τὸ κάθαρμα, τὸ παίγνιον, ὁ ξυλινὸς νοῦς, αἴτιος, ὁ γράψας Αἴτια Καλλίμαχος. Callimachus, that discard, that plaything, that mahogany noggin, Himself

156-461: A larger size. The geological record of Thalassiosira dates back to 13.82 million years ago. The fossil record of both freshwater and marine Thalassiosira organisms is substantial, though the freshwater collection has been characterized more extensively. T. pseudonana has been particularly useful for molecular studies due to its small genome size. It has revealed novel pathways for silica biosynthesis, which involve uptake of monosilicic acid from

195-465: A later period by the figure of Thalassa, especially in Western Asia . There she was depicted as a woman clothed in bands of seaweed and half submerged in the sea, with the crab-claw horns that were formerly an attribute of Oceanus now transferred to her head. In one hand she holds a ship's oar, and in the other a dolphin. In 2011, Swoon created a site-specific installation depicting the goddess in

234-403: A model organism for understanding diatom biology. Whole genome sequencing, transcriptomics and proteomics of T. pseudonana have revealed novel pathways for silicon biogenesis, phosphorus stress response, intracellular transport and metabolism in marine diatoms. Recent genetic studies using ribosomal RNA gene sequences better distinguish and classify Thalassiosira species and metabolomics defines

273-411: A prolific author. Apollonius set out to integrate new understandings of the physical world with the mythical geography of tradition and his Argonautica was, in that sense, a didactic epic on geography, again without detracting from its merits as poetry. The Argonautica differs in some respects from traditional or Homeric Greek epic, though Apollonius certainly used Homer as a model. The Argonautica

312-439: A renaissance of interest in the poem and an awareness of its qualities: numerous scholarly studies are published regularly, its influence on later poets like Virgil is now well recognised, and any account of the history of epic poetry now routinely includes substantial attention to Apollonius. A handful of fragments are all that survive of his other work, mostly ktiseis ( κτίσεις ) or 'foundation-poems', apparently dealing with

351-404: A unique time in history. The most reliable information we have about ancient poets is largely drawn from their own works. Unfortunately, Apollonius of Rhodes reveals nothing about himself. Most of the biographical material comes from four sources: two are texts entitled Life of Apollonius found in the scholia on his work ( Vitae A and B); a third is an entry in the 10th-century encyclopaedia

390-702: A vital primary producers in temperate and polar regions. Thalassiosira can thrive in low temperature and light, as well as mixed waters, and are therefore a large part of diatom blooms during spring in temperate regions, such as Canadian and Alaskan waters. Species in this genus are also capable of assembling defensive threads against zooplankton, allowing them to survive the predation that normally keeps phytoplankton blooms in check. Thalassiosira species are diverse in both their ecology and physiologies, with variable mechanisms for nitrogen storage or requirements for iron. Iron concentrations, temperature and macronutrient availability have been identified as important factors for

429-399: Is also considered to be one of the period's most important authors on geography, though approaching the subject differently from Eratosthenes , his successor at the library and a radical critic of Homer's geography. It was a time when the accumulation of scientific knowledge was enabling advances in geographical studies, as represented by the activities of Timosthenes , a Ptolemaic admiral and

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468-489: Is pattered with a series of bands. Different species of Thalassiosira can be identified by the morphological characteristics of their areolae and the processes on the valve. During colony formation, Thalassiosira release chitin filaments through strutted processes known as fultoportulae. By extruding chitin fibers, and thereby increasing drag, Thalassiosira can slow the rate at which they sink. Thalassiosira occupy diverse habitats, both marine and freshwater. Of note, they are

507-499: Is shorter than Homer's epics, with four books totalling fewer than 6000 lines, while the Iliad runs to more than 16,000. Apollonius may have been influenced here by Callimachus's brevity, or by Aristotle ’s demand for "poems on a smaller scale than the old epics, and answering in length to the group of tragedies presented at a single sitting" (the Poetics ). Apollonius' epic also differs from

546-401: Is triggered by an assortment of environmental factors, which are not well understood, once cells reach a critically small size. In sexual reproduction, sperm and egg, which can arise from the same cell, fuse to form a diploid zygote, which is referred to as an auxospore. This progeny can then emerge from the parental frustule (silica wall) and reconstruct its own cell wall, thus becoming a cell of

585-512: The Suda ; and fourthly a 2nd-century BCE papyrus, P.Oxy. 1241, which provides names of several heads of the Library of Alexandria . Other scraps can be gleaned from miscellaneous texts. The reports from all the above sources however are scanty and often self-contradictory. Ancient biographies often represent famous poets as going into exile to escape their ungrateful fellow citizens. Thus for example Homer

624-470: The Argonautica in such fine style at Rhodes that he was able to return to Alexandria in triumph, where he was rewarded with a post in the library and finally a place in the cemetery next to Callimachus. These stories were probably invented to account for the existence of a second edition of Argonautica , indicated by variant readings in ancient manuscripts. Until recently modern scholarship has made much of

663-569: The Argonauts and their quest for the Golden Fleece . The poem is one of the few extant examples of the epic genre and it was both innovative and influential, providing Ptolemaic Egypt with a "cultural mnemonic" or national "archive of images", and offering the Latin poets Virgil and Gaius Valerius Flaccus a model for their own epics. His other poems, which survive only in small fragments, concerned

702-588: The T. pseudonana genome was the presence of genes encoding enzymes for a complete urea cycle, which was unprecedented in a photosynthetic eukaryote. Diatoms are known to utilize a urease enzyme to catalyze the breakdown of urea and were therefore not expected to need mechanisms to excrete it as waste. Curiously, the T. pseudonana urea cycle feeds into other metabolic pathways, which contribute to protein biosynthesis and possibly energy storage. Thalassiosira can undergo both asexual and sexual reproduction in processes shared by other diatoms. During asexual reproduction,

741-544: The sea-nymph Halia , while in the Orphic Hymn to the Sea , Tethys , who is here equated with Thalassa, is called the mother of Kypris ( Aphrodite ). The Roman mythographer Hyginus (c. 64 BC – AD 17), in the preface to his Fabulae , calls Mare (Sea, another name for Thalassa) the daughter of Aether and Dies (Day), and thus the sister of Terra (Earth) and Caelus (Sky). With her male counterpart Pontus , she spawns

780-415: The 1950s and scanning electron microscopy in the 1960s, which led to an enhanced understanding of the defining morphological features of the genus and the subsequent recognition of over 100 species A species of Thalassiosira , T. pseudonana , was selected as the first marine eukaryotic phytoplankton to undergo whole genome sequencing, due to its small 34Mb genome. As a result, T. pseudonana has served as

819-605: The 2nd century CE, Lucian represented Thalassa in a comic dialogue with Xanthus, the god of the River Scamander , who had been attacked by a rival Greek deity for complaining that his course was being choked with dead bodies during the Trojan War . In this case he had been badly scorched and asks her to soothe his wounds. While the sea-divinities Tethys and Oceanus were formerly represented in Roman-era mosaics, they were replaced at

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858-601: The atrium of the New Orleans Museum of Art . In fall 2016, the installation was erected once more in the atrium of the Detroit Institute of Arts . Apollonius of Rhodes Apollonius of Rhodes ( Ancient Greek : Ἀπολλώνιος Ῥόδιος Apollṓnios Rhódios ; Latin : Apollonius Rhodius ; fl. first half of 3rd century BC) was an ancient Greek author , best known for the Argonautica , an epic poem about Jason and

897-472: The beginnings or foundations of cities, such as Alexandria and Cnidus places of interest to the Ptolemies, whom he served as a scholar and librarian at the Library of Alexandria . A literary dispute with Callimachus , another Alexandrian librarian/poet, is a topic much discussed by modern scholars since it is thought to give some insight into their poetry, although there is very little evidence that there ever

936-540: The composition of Thalassiosira species communities in marine waters. Phylogenetic studies based on 18S rRNA genes have revealed several clades within Thalassiosira , an overall paraphyletic group within the family Thalassiosirales. The relationships of species within the clades remain to be elucidated. The sequence of the T. pseudonana genome revealed a host of features which set apart diatoms from other eukaryotes. For instance, heat shock transcription factors make up

975-533: The epic, following the Hellenistic trend to allegorise and rationalise religion. Heterosexual loves such as Jason's are more emphasized than homosexual loves such as that of Heracles and Hylas , another trend in Hellenistic literature. Many critics regard the love of Medea and Jason in the third book as the best written and most memorable episode. Opinions on the poem have changed over time. Some critics in antiquity considered it mediocre. Recent criticism has seen

1014-952: The feud, but most scholars of Hellenistic literature now believe it has been enormously sensationalised, if it happened at all. Apollonius was among the foremost Homeric scholars in the Alexandrian period. He wrote the period's first scholarly monograph on Homer, critical of the editions of the Iliad and Odyssey published by Zenodotus , his predecessor as head of the Library of Alexandria. Argonautica seems to have been written partly as an experimental means of communicating his own researches into Homer's poetry and to address philosophical themes in poetry. It has even been called "a kind of poetic dictionary of Homer", without at all detracting from its merits as poetry. He has been credited with scholarly prose works on Archilochus and on problems in Hesiod . He

1053-399: The first marine phytoplankton to have its genome sequenced. T. pseudonana has since become a key model organism for studying diatom physiology. The T. pseudonana genome revealed novel genes for intracellular trafficking and metabolism in diatoms. This species was again used to develop methods for genetic manipulation of diatoms and for the study of silica biomineralization. Thalassiosira

1092-498: The majority of transcription factors in the T. pseudonana genome, though they are less common in other eukaryotes. Also setting it apart from other eukaryotic genomes is the relative absence of receptor kinases and G protein-coupled receptors. More specific to diatom biology, the understanding of silicon biochemistry in diatoms was enhanced by the discovery of genes involved in the uptake of silicic acid and proteins involved in vesicles for silica precipitation. A surprising finding from

1131-654: The marine environment, intracellular transport to a specialized vesicle, and specialized enzymes and peptides driving silica synthesis. Silica biosynthesis, for which the species T. pseudonana has come to serve as a model organism for study, has been of particular interest in the context of engineering silica nanotechnology. For instance, a modified T. pseudonana has been explored as a drug-delivery vesicle in cancer treatment. Thalassiosira , among other diatoms, have also been considered as potentially useful sources of lipids for biofuels. Specifically, T. weissflogii has been shown to reduce its silica synthesis while upregulating

1170-412: The more traditional epic in its weaker, more human protagonist Jason and in its many digressions into local custom, aetiology , and other popular subjects of Hellenistic poetry. Apollonius also chooses the less shocking versions of some myths, having Medea , for example, merely watch the murder of Apsyrtus instead of murdering him herself. The gods are relatively distant and inactive throughout much of

1209-448: The organic compounds produced by Thalassiosira. Thalassiosira come in a variety of shapes, from box-shaped to cylindrical, discoid or spherical. Some Thalassiosira cells are found alone while others form chains. Thalassiosira have a cell wall made of silica, known as a frustule. Thalasiosira harbor several discoid plastids and a circular valve, which contains pores arranged in rows or arcs, opening outwards. The valve’s mantle edge

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1248-409: The parent cell divides into two daughter cells of unequal size — one equal in size to the parent and one smaller. This constraint on size during mitotic division is due to the presence of the rigid silica cell wall. As a result, over multiple cell divisions, the cells size of each daughter cell will decrease. To cope with diminishing cell size, Thalassiosira can transition to sexual reproduction, which

1287-522: The production of triacylglycerols when cultured in nitrogen-limiting conditions. Thalassa According to a scholion on Apollonius of Rhodes , the fifth-century BC poet Ion of Chios had Thalassa as the mother of Aegaeon (Briareus, one of the Hecatoncheires ). Diodorus Siculus ( fl. 1st century BC), in his Bibliotheca historica , states that "Thalatta" is the mother of the Telchines and

1326-491: The same excuse. But for the winds, "by nature I am as calm and safe as the land." In yet another fable, Perry's number 412 and only recorded by Syntipas , the rivers complain to the sea that their sweet water is turned undrinkably salty by contact with her. The sea replies that if they know as much, they should avoid such contact. The commentary suggests that the tale may be applied to people who criticize someone inappropriately even though they may actually be helping them. In

1365-482: The species of fish. Two rather similar fables are recorded by Babrius . In one, numbered 168 in the Perry Index , a farmer witnesses a shipwreck and reproaches the sea for being "an enemy of mankind". Assuming the form of a woman, she answers by blaming the winds for her turbulence. Otherwise, "I am gentler than that dry land of yours." In the other, a survivor from a shipwreck accuses the sea of treachery and receives

1404-449: Was finally driven out of Alexandria by a triumphant Callimachus". However, both of the Lives of Apollonius stress the friendship between the poets, the second Life even saying they were buried together; moreover Callimachus's poem Ibis is known to have been deliberately obscure and some modern scholars believe the target was never meant to be identified. There is still not a consensus about

1443-512: Was first described in 1873 by P.T. Cleve. The genus name of Thalassiosira is named after Thalassa the Greek word for the 'sea' and for its divine female personification in Greek mythology Cleve noted "The Thalassiosira ... occurs in enormous large masses, floating on the surface of the sea and colouring it for many miles in extent". The genus was then characterized with transmission electron microscopy in

1482-517: Was said to have left Cyme because the government there would not support him at public expense ( Vit. Herod. 13-14), Aeschylus left Athens for Sicily because Athenians valued him less than some other poets ( Vit. Aesch. ), while Euripides fled to Macedonia because of humiliation by comic poets ( Vit. Eur. ). Similarly Vitae A and B tell us that Apollonius moved to Rhodes because his work was not well received in Alexandria. According to B, he redrafted

1521-420: Was such a dispute between the two men. In fact almost nothing at all is known about Apollonius and even his connection with Rhodes is a matter for speculation. Once considered a mere imitator of Homer , and therefore a failure as a poet, his reputation has been enhanced by recent studies, with an emphasis on the special characteristics of Hellenistic poets as scholarly heirs of a long literary tradition writing at

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