Matthew L Julius

St. Cloud State University · Department of Biology

Understanding how animals respond to large-scale environmental changes is difficult to achieve because monitoring data are rarely available for more than the past few decades, if at all. Here, we demonstrate how a variety of palaeoecological proxies (e.g. isotopes, geochemistry and DNA) from an Andean Condor (Vultur gryphus) guano deposit from Arge...

The epilithic diatom Karthickia verestigmata Glushchenko et al. was described from North Viet Nam and Laos. Karthickia is a monotypic genus characterized by a unique ‘stigma’ located on the secondary side of the valve with an external circular opening and opening internally by two elongated slits. In 2012 we collected a diatom population consistent...

Diatoms are unicellular eukaryotic algae that have a distinctive siliceous cell wall (frustule) with unique architectures. The nanotopography of the frustule is perfectly replicated between generations, offering a source of highly intricate and identical silica microparticles. In recent years, the ability to alter their cell wall chemistry both in...

A strong consensus has emerged that taxonomic classifications should be based on an underlying phylogenetic hypothesis. According to this view, named groups should be monophyletic, ensuring that a name uniquely matches the evolutionary history and biological attributes of a group of taxa. As originally conceived, the diatom genus Cyclotella is a la...

The large population sizes and high dispersal potential of microbes suggests that a given microbial species should be found in all suitable habitats worldwide. Consequently, microbes should not exhibit the kinds of biogeographic patterns seen in macroorganisms. This paradigm is challenged by a growing list of exotic microbes with biogeographic disj...

Bone scaffolds are often fabricated by initially producing custom-made filaments by twin-screw extruder and subsequently fabricating into 3D scaffolds using fused deposition modelling. This study aims to directly compare the effect of two alternative silica-rich filler materials on the thermo-mechanical properties of such scaffolds after extrusion...

Silica incorporation into biomaterials, such as Bioglass and Si-substituted calcium phosphate ceramics has received significant attention in bone tissue engineering over the last few decades. This study aims to explore the dissolution behaviour of natural biosilica isolated from a freshwater diatom, Cyclotella meneghiniana, that has been incorporat...

Analysis of a 195-cm core extracted from Polecat Bay (PB) in southern Alabama revealed that dramatic changes in diatom abundance/composition and sediment type took place sometime in the past. Examination of historical records and interviews with witnesses to industrial activity suggest that the changes were largely anthropogenically driven and caus...

The valorisation of Anaerobic digestion waste streams into algal biomass to produce a protein alternative to soybeans could have significant commercial and environmental value. It has the benefit of alleviating the pressure of disposal of nutrient-rich digestate that is rich in nitrogen, phosphorous and trace metals, while potentially reducing the...

Diatoms are one of the earth's major oxygen producers. For that reason, studying the floating phenomena of living diatom cells in water is an important research subject. Efficiency of photosynthesis of diatom cells may be heavily affected by their floating behavior. In our previous research, we devised a ‘tumbled’ microscope, a device created by ti...

Coccolithophores are unicellular marine phytoplankton, which produce intricate, tightly regulated, exoskeleton calcite structures. The formation of biogenic calcite occurs either intracellularly, forming ‘wheel-like’ calcite plates, or extracellularly, forming ‘tiled-like’ plates known as coccoliths. Secreted coccoliths then self-assemble into mult...

Salmonella can survive for long periods under extreme desiccation conditions. This stress tolerance poses a risk for food safety, but relatively little is known about the molecular and cellular regulation of this adaptation mechanism. To determine the genetic components involved in Salmonella’s cellular response to desiccation, we performed a globa...

Schematic representation of the mutants and of the genomic regions amplified for PCR verification. Schematic drawing of the S. enterica serovar Typhimurium wild-type sopD and sseD gene knock-out mutations with the chloramphenicol resistance cassette and the kanamycin resistance cassette, respectively (A). The sites of λ Red-mediated homologous reco...

Primers used for PCR verification and sequencing of the ΔsopD and ΔsseD mutants. (PDF)

List of genes differentially expressed (more than 2-fold change) in S. enterica serovar Typhimurium wild-type equilibrated to aw 0.11 on filters. (PDF)

Porous silica is an attractive biomaterial in many applications, including drug-delivery systems, bone-graft fillers and medical devices. The issue with porous silica biomaterials is the rate at which they resorb and the significant role played by interfacial chemistry on the host response in vivo. This paper explores the potential of diatom-biosil...

Since being described in 2008, Spicaticribra has been reported globally. Here, the genus is reported in collections from Africa for the first time. Its habitat and morphology are very similar from locality to locality. As with most other reports, the material collected was obtained from a reservoir. We compare rotational symmetry in the marginal st...

A major draw-back to large scale production of bioactive glasses is the high cost of the standard silica precursor, usually tetraethyl orthosilicate (TEOS). The current study describes a novel sol–gel preparation of 45S5 bioactive glass using diatom biosilica from cultured cells of the diatom, Aulacoseira granulata as substitute to TEOS. The glass...

A new diatom, Discostella oyanensis sp. nov., is described from plankton samples obtained from a Nigerian reservoir. This species level designation is supported by the combination of morphological features exhibited in the taxon. It represents the third species described from the African continent in this globally distributed genus. Discostella oya...

Scientists building the Tree of Life face an overwhelming challenge to categorize phenotypes (e.g., anatomy, physiology) from millions of living and fossil species. This biodiversity challenge far outstrips the capacities of trained scientific experts. Here we explore whether crowdsourcing can be used to collect matrix data on a large scale with th...

The diatoms are a successful group of eukaryotic, photosynthetic microbes that occur in nearly every place there is or has been; that place being water. With over 64,000 named entities, they are one of the most diverse groups of algae. The groups of freshwater diatoms, known as "centric" and "araphid", occur in a wide variety of lotic and lentic sy...

A series of intermittent changes in Stephanodiscus (Bacillariophyta) valve morphology was observed in sediment core materials collected from Lake Biwa, Japan. A constant sedimentation rate reveals a continuous but punctuated pattern of morphological evolution. Morphological parameters, including maximum diameter and fascicle number v. diameter rati...

Cyclotella is a commonly encountered name in the diatom literature. The name is attached, however, to a historically vaguely defined and polyphyletic genus whose taxonomy and systematics remain muddled despite numerous taxonomic treatments. One recent chapter in this history concerns species informally known as the " Cyclotella comta " group, which...

Abstract: A new genus, Praestephanos, is described with its type species based on Stephanodiscus suzukii. In addition, two new combinations are described: P. triporus and P. carconensis. This genus is similar to the genus Stephanodiscus, however, the pattern of the areolae changes at the level of the marginal fultoportulae but not at the level of t...

The 21 st International Diatom Symposium (IDS) convened from 29 August to 03 September 2010 at the Crown Plaza Hotel in downtown St. Paul, Minnesota, USA. Over 135 delegates representing 23 countries attended the symposium and enjoyed keynote addresses by Drs John Smol and Ellinor Michel. Delegates participated in special sessions on Genetic Barcod...

The phenotype represents a critical interface between the genome and the environment in which organisms live and evolve. Phenotypic characters also are a rich source of biodiversity data for tree building, and they enable scientists to reconstruct the evolutionary history of organisms, including most fossil taxa, for which genetic data are unavaila...

Wild rice (Zizania spp. L.) is a North American native grain with spiritual and dietary significance to many native people. Wild rice is also an important aquatic plant that provides critical habitat to wetland and aquatic wildlife. Past distribution of wild rice in North America is poorly understood, largely because of the limited taxonomic resolu...

The eutrophic, freshwater diatom species Stephanodiscus binderanus (Ku¨tz.) Willi Krieg. has long been considered a nuisance exotic alga introduced from Eurasia to the Great Lakes in North America in the early to mid-20th century. However, our paleolimnological data from Lake Simcoe, Ontario, provide unequivocal evidence that this taxon has been pr...

Scanning electron micrographs of thalassiosiroid diatoms in the type material (Additional file 4) of Cyclotella nana (= Thalassiosira pseudonana): Stephanodiscus hantzschii Grunow (A, B), Stephanodiscus minutulus (Kützing) Cleve & Möller (C, D), Discostella pseudostelligera (Hustedt) Houk & Klee (E-H), Cyclotella striata (Kützing) Grunow in Cleve &...

Scanning electron micrographs showing exterior (A, B) and interior (C, D) views of Thalassiosira pseudonana (marine strain NEPC709) from Alverson et al. [25]. Scale bar = 2 μM.

Strict consensus of eight most parsimonious trees from a phylogenetic analysis of 32 morphological characters for select Thalassiosirales.

The nomenclatural history of Thalassiosira pseudonana.

The identity of Thalassiosira pseudonana.

Hustedt's observations on the type locality of Cyclotella nana (= T. pseudonana).

Pairwise differences among Thalassiosira pseudonana culture strains at four loci.

Publication of the first diatom genome, that of Thalassiosira pseudonana, established it as a model species for experimental and genomic studies of diatoms. Virtually every ensuing study has treated T. pseudonana as a marine diatom, with genomic and experimental data valued for their insights into the ecology and evolution of diatoms in the world's...

Environmental pressures may vary over the geographic range of a species, exposing subpopulations to divergent functional demands. How does exposure to competing demands shape the morphology of species and influence the divergence of populations? We explored these questions by performing selection experiments on juveniles of the Hawaiian goby Sicyop...

Introduction Diatoms have long been lauded for their use as powerful and reliable environmental indicators (Cholnoky, 1968; Lowe, 1974). This utility can be attributed to their high abundance and species diversity, which are distributed among most aquatic environments. Additionally, their remains are highly durable and well preserved in accumulated...

The effects of embryonic and larval exposure to environmentally relevant (ng/L) concentrations of common antidepressants, fluoxetine, sertraline, venlafaxine, and bupropion (singularly and in mixture) on C-start escape behavior were evaluated in fathead minnows (Pimephales promelas). Embryos (postfertilization until hatching) were exposed for 5 d a...

The effects of embryonic and larval exposure to environmentally relevant (ng/L) concentrations of common antidepressants, fluoxetine, sertraline, venlafaxine, and bupropion (singularly and in mixture) on C-start escape behavior were evaluated in fathead minnows (Pimephales promelas). Embryos (postfertilization until hatching) were exposed for 5 d a...

Aquatic organisms exposed to endocrine disrupting compounds (EDCs) at early life-stages may have reduced reproductive fitness via disruption of reproductive and non-reproductive behavioral and physiological pathways. Survival to reproductive age relies upon optimal non-reproductive trait expression, such as adequate predator avoidance responses, wh...

Flow characteristics are a prominent factor determining body shapes in aquatic organisms, and correlations between body shape and ambient flow regimes have been established for many fish species. In this study, we investigated the potential for a brief period of extreme flow to exert selection on the body shape of juvenile climbing Hawaiian gobiid...

Many toxic effects of treated wastewater effluent on organismal and reproductive health have been documented. However, the physicochemical environment of treated wastewater effluent frequently differs considerably from that of its receiving waters and may affect organismal function independently of toxic effects. Teleost sperm, for example, may be...

Estrogenic compounds have been discovered in many surface water samples in many anthropogenically altered surface waters. Wastewater effluent has been identified as a major pathway of contamination and found to revert much of the metabolic products of these biologically active compounds back to their original form. This presentation explains method...

Juveniles from three species of Hawaiian gobiid fishes climb waterfalls as part of an amphidromous life cycle, allowing them to re-penetrate adult upstream habitats after being swept out to the ocean upon hatching. The importance of climbing for juvenile stream gobies is well established, but adult fish in upstream island habitats also face potenti...

The understanding of diatom evolution has progressed greatly over the last two decades. Existing data sets have been reanalyzed, new data sets have been generated, and new tools have been employed. Hindering progress is the seemingly endless number of diatom species remaining to be described and relative small number of investigators active in the...

Juveniles from three species of Hawaiian gobiid fishes climb waterfalls as part of an amphidromous life cycle, allowing them to re-penetrate adult upstream habitats after being swept out to the ocean upon hatching. The importance of climbing for juvenile stream gobies is well established, but adult fish in upstream island habitats also face potenti...

Microalgae are well known for their importance in aquatic ecosystems and for their utility as environ-mental indicators. These attributes are emphasized here for microalgae, especially diatoms, occurring in Hawaiian stream systems. Attention is paid to the influences stream morphology has on the distri-bution of algae in streams on Hawai'i and Kaua...

SUMMARYA new fossil diatom, Stephanodiscus kusuensis sp. nov., is described from a diatomite deposit from the Kusu Basin, Oita Prefecture Japan. Radiometric age estimates of the strata in which the taxon occurs are 400–500 kyr. The new species is distinct from all other known species of Stephanodiscus because it possesses a highly pronounced double...

Juveniles of three species of Hawaiian gobiid fishes climb waterfalls during migration to adult habitats using two kinematically distinct patterns: Awaous guamensis and Lentipes concolor use rapid, intermittent bouts of axial undulation (‘powerbursts’), whereas Sicyopterus stimpsoni inches up waterfalls by alternately attaching oral and pelvic suck...

This laboratory exercise introduces students to a fundamental tool in evolutionary biology--phylogenetic inference. Students are required to create a data set via observation and through mining preexisting data sets. These student data sets are then used to develop and compare competing hypotheses of vertebrate phylogeny. The exercise uses readily...

Gut contents of larval, juvenile, and adult specimens of the Hawaiian gobiid fish Sicyopterus stimpsoni were examined to catalog the algal flora ingested by this species. The developmental stages of S. stimpsoni examined represented hallmark points in the fish’s life cycle corresponding with major migratory and metamorphic transitions. The algal fl...

A small ichthyological fauna has been sustained for at least eight years in two fissures in an extensive lava shield on the southeastern coast of the Island of Hawai'i. This freshwater ecosystem contains bacterial mats that likely serve as food source for Macrobrachium grandimanus, the only species of macro-invertebrate found in the cracks. Six spe...

Biogenically active compounds have been discovered in many surface water samples in Europe and North America. Wastewater effluent is identified as a major source of contamination and found to revert much of the metabolic products of these biologically active compounds back to their original form. This presentation explains methodology for determini...

Population dynamics and health for individual Great Lakes diatom species is explored. Information dealing with how these taxa compete with introduced species and rapid environmental changes in modern times is examined. Diatomists have identified a number of these taxa, but discussion is limited with little or no information covering the ecological...

The morphology of a new centric diatom species, Stephanodiscus akanensis Tuji, Kawashima, Julius & Stoermer is described using light and scanning electron microscopy. The species is so far only known from Lake Akan, Hokkaido, Japan. It is separated from other similar Stephanodiscus species by the characteristic position of the valve face fultoportu...

Lake Michigan provides an ideal location for comparing episodic physical forcing events (storms) on phytoplankton processes and the more persistent seasonal variability of phytoplankton communities. This is due to the duration and extent of the highly turbid, recurrent coastal plume (RCP) in the lake during the winter/early spring. Although the RCP...

Nineteen Thalassiosira species informally referred to as the plicated Thalassiosira were examined in a cladistic analysis. The species range in age from 17 Ma to modern, representing the earliest known members of the group and its most recent members. Two most parsimonious cladograms were discovered, generally agreeing with the occurrence of specie...

The thalassiosiroid centric diatoms are distinguished by at least one synapomorphy, the strutted process or fultoportula. Variously classified as a family (Thalassiosiraceae) or an order (Thalassiosirales) among centric diatoms, it is generally conceded that the group of several hundred fossil and living species is monophyletic as a whole. There ar...

Lake Michigan provides an ideal location for comparing episodic physical forcing effects (storm events) on phytoplankton processes and the more persistent seasonal variability of phytoplankton communities. This is because of the duration and extent of the highly turbid, recurrent coastal plume (RCP) in the lake during the winter/early spring. Altho...

The phylogeny of the Cyclostephanoid diatoms was investigated. Although several species in this group are important indicators of water quality and biostratigraphy, this is the first formal systematic study of the group. Phylogenetic reconstruction was performed for exemplar taxa within the group. The investigation utilized frustule morphology and...

We investigated microfossil assemblages in recent sediments from nine stations across Lake Ontario. Stephanodiscus niagarae was not present in any of these sediment samples, marking the taxon’s extirpation from its type locality. This observation documents the end of a general reduction in size and alteration in valve morphology associated with hab...

Since the early 1960s, numerical techniques have produced a wide variety of methods to suggest classifications of organisms based on quantitative measurements. A long-recognized shortcoming of these methods is that they will suggest classifications for any group of organisms and any set of measurements, whether or not the clusters in the suggested...

Siliceous microfossil assemblage succession was analyzed in a 100 m sediment core from Lake Baikal, Siberia. The core was recovered from the lake's central basin at a water depth of 365 m. Microfossil abundance varied greatly within the intervals sampled, ranging from samples devoid of siliceous microfossils to samples with up to 3.49 10 11 microfo...

Analysis of diatom assemblages preserved in a 210Pb-dated core from Lake Erie's central basin indicates rapid recent ecological change in the system. Sediments deposited after ca. 1972 contain increasing numbers of diatom populations associated with oligotrophic conditions, particularly Cyclotella species, which grow in the summer deep chlorophyll...

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Thesis (M.S.)--University of Michigan, 1995. Includes bibliographical references.