Biology

9 pages, 125 KiB

Open AccessReview

Marine Invertebrates: Communities at Risk

by Jennifer Mather

Psychology Department, University of Lethbridge, 4401 University Drive, Lethbridge, AB, T1K 3M4, Canada

Biology 2013, 2(2), 832-840; https://doi.org/10.3390/biology2020832 - 10 Jun 2013

Cited by 7 | Viewed by 8414

Our definition of the word ‘animal’ centers on vertebrates, yet 99% of the animals on the planet are invertebrates, about which we know little. In addition, although the Census of Marine Life (COML.org) has recently conducted an extensive audit of marine ecosystems, we [...] Read more.

Our definition of the word ‘animal’ centers on vertebrates, yet 99% of the animals on the planet are invertebrates, about which we know little. In addition, although the Census of Marine Life (COML.org) has recently conducted an extensive audit of marine ecosystems, we still do not understand much about the animals of the seas. Surveys of the best-known ecosystems, in which invertebrate populations often play a key role, show that the invertebrate populations are affected by human impact. Coral animals are the foundation of coral reef systems, which are estimated to contain 30% of the species in the ocean. Physical impact and chemical changes on the water severely damage these reefs, and may lead to the removal of these important habitats. Tiny pteropod molluscs live in huge numbers in the polar seas, and their fragile shells are particularly vulnerable to ocean acidification. Their removal would mean that fishes on which we depend would have a hugely diminished food supply. In the North Sea, warming is leading to replacement of colder water copepods by warmer water species which contain less fat. This is having an effect on the birds which eat them, who enrich the otherwise poor land on which they nest. Conversely, the warming of the water and the loss of top predators such as whales and sharks has led to an explosion of the jumbo squid of the Pacific coast of North America. This is positive in the development of a squid fishery, yet negative because the squid eat fish that have been the mainstay of the fishery along that coast. These examples show how invertebrates are key in the oceans, and what might happen when global changes impact them. Full article

22 pages, 266 KiB

Open AccessReview

Adhesion of Diarrheagenic Escherichia coli and Inhibition by Glycocompounds Engaged in the Mucosal Innate Immunity

by Alex L. Pereira^1,2,* and Loreny G. Giugliano²

¹ College of Ceilândia, University of Brasília, Brasília-DF, 72220-900, Brazil

² Laboratory of Microbiology, Department of Cellular Biology, University of Brasília, Brasília-DF, 70910-900, Brazil

Biology 2013, 2(2), 810-831; https://doi.org/10.3390/biology2020810 - 7 Jun 2013

Cited by 7 | Viewed by 9307

Abstract

Escherichia coli colonizes the human intestine shortly after birth, with most strains engaging in a commensal relationship. However, some E. coli strains have evolved toward acquiring genetic traits associated with virulence. Currently, five categories of enteroadherent E. coli strains are well-recognized, and are [...] Read more.

Escherichia coli colonizes the human intestine shortly after birth, with most strains engaging in a commensal relationship. However, some E. coli strains have evolved toward acquiring genetic traits associated with virulence. Currently, five categories of enteroadherent E. coli strains are well-recognized, and are classified in regard to expressed adhesins and the strategy used during the colonization. The high morbidity associated with diarrhea has motivated investigations focusing on E. coli adhesins, as well on factors that inhibit bacterial adherence. Breastfeeding has proved to be the most effective strategy for preventing diarrhea in children. Aside from the immunoglobulin content, glycocompounds and oligosaccharides in breast milk play a critical role in the innate immunity against diarrheagenic E. coli strains. This review summarizes the colonization factors and virulence strategies exploited by diarrheagenic E. coli strains, addressing the inhibitory effects that oligosaccharides and glycocompounds, such as lactoferrin and free secretory components, exert on the adherence and virulence of these strains. This review thus provides an overview of experimental data indicating that human milk glycocompounds are responsible for the universal protective effect of breastfeeding against diarrheagenic E. coli pathotypes. Full article

(This article belongs to the Special Issue Bacterial Adhesion)

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12 pages, 624 KiB

Open AccessArticle

Fungal Diversity in a Dark Oligotrophic Volcanic Ecosystem (DOVE) on Mount Erebus, Antarctica

by Laurie Connell^1,* and Hubert Staudigel²

¹ School of Marine Sciences, University of Maine, Orono, ME 04496, USA

² Institute of Geophysics and Planetary Physics, Scripps Institution of Oceanography, La Jolla, CA 92093, USA

Biology 2013, 2(2), 798-809; https://doi.org/10.3390/biology2020798 - 30 May 2013

Cited by 45 | Viewed by 10163

Abstract

Fumarolic Ice caves on Antarctica’s Mt. Erebus contain a dark oligotrophic volcanic ecosystem (DOVE) and represent a deep biosphere habitat that can provide insight into microbial communities that utilize energy sources other than photosynthesis. The community assembly and role of fungi in these [...] Read more.

Fumarolic Ice caves on Antarctica’s Mt. Erebus contain a dark oligotrophic volcanic ecosystem (DOVE) and represent a deep biosphere habitat that can provide insight into microbial communities that utilize energy sources other than photosynthesis. The community assembly and role of fungi in these environments remains largely unknown. However, these habitats could be relatively easily contaminated during human visits. Sixty-one species of fungi were identified from soil clone libraries originating from Warren Cave, a DOVE on Mt. Erebus. The species diversity was greater than has been found in the nearby McMurdo Dry Valleys oligotrophic soil. A relatively large proportion of the clones represented Malassezia species (37% of Basidomycota identified). These fungi are associated with skin surfaces of animals and require high lipid content for growth, indicating that contamination may have occurred through the few and episodic human visits in this particular cave. These findings highlight the importance of fungi to DOVE environments as well as their potential use for identifying contamination by humans. The latter offers compelling evidence suggesting more strict management of these valuable research areas. Full article

(This article belongs to the Special Issue Polar Microbiology: Recent Advances and Future Perspectives)

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14 pages, 459 KiB

Open AccessArticle

Antarctic Epilithic Lichens as Niches for Black Meristematic Fungi

by Laura Selbmann^1,*, Martin Grube², Silvano Onofri¹

, Daniela Isola¹

and Laura Zucconi¹

¹ Department of Ecological and BiologicalSciences (DEB), University of Tuscia, Largo dell'Università snc, Viterbo 01100, Italy

² Institute of Plant Sciences, Karl-Franzens-University Graz, Holteigasse 6, A-8010 Graz, Austria

Biology 2013, 2(2), 784-797; https://doi.org/10.3390/biology2020784 - 17 May 2013

Cited by 58 | Viewed by 12432

Abstract

Sixteen epilithic lichen samples (13 species), collected from seven locations in Northern and Southern Victoria Land in Antarctica, were investigated for the presence of black fungi. Thirteen fungal strains isolated were studied by both morphological and molecular methods. Nuclear ribosomal 18S gene sequences [...] Read more.

Sixteen epilithic lichen samples (13 species), collected from seven locations in Northern and Southern Victoria Land in Antarctica, were investigated for the presence of black fungi. Thirteen fungal strains isolated were studied by both morphological and molecular methods. Nuclear ribosomal 18S gene sequences were used together with the most similar published and unpublished sequences of fungi from other sources, to reconstruct an ML tree. Most of the studied fungi could be grouped together with described or still unnamed rock-inhabiting species in lichen dominated Antarctic cryptoendolithic communities. At the edge of life, epilithic lichens withdraw inside the airspaces of rocks to find conditions still compatible with life; this study provides evidence, for the first time, that the same microbes associated to epilithic thalli also have the same fate and chose endolithic life. These results support the concept of lichens being complex symbiotic systems, which offer attractive and sheltered habitats for other microbes. Full article

(This article belongs to the Special Issue Polar Microbiology: Recent Advances and Future Perspectives)

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29 pages, 483 KiB

Open AccessReview

Biotechnology of Cold-Active Proteases

by Swati Joshi and Tulasi Satyanarayana^*

Department of Microbiology, University of Delhi South Campus, New Delhi 110021, India

Biology 2013, 2(2), 755-783; https://doi.org/10.3390/biology2020755 - 3 May 2013

Cited by 100 | Viewed by 13705

Abstract

The bulk of Earth’s biosphere is cold (<5 °C) and inhabited by psychrophiles. Biocatalysts from psychrophilic organisms (psychrozymes) have attracted attention because of their application in the ongoing efforts to decrease energy consumption. Proteinases as a class represent the largest category of industrial [...] Read more.

The bulk of Earth’s biosphere is cold (<5 °C) and inhabited by psychrophiles. Biocatalysts from psychrophilic organisms (psychrozymes) have attracted attention because of their application in the ongoing efforts to decrease energy consumption. Proteinases as a class represent the largest category of industrial enzymes. There has been an emphasis on employing cold-active proteases in detergents because this allows laundry operations at ambient temperatures. Proteases have been used in environmental bioremediation, food industry and molecular biology. In view of the present limited understanding and availability of cold-active proteases with diverse characteristics, it is essential to explore Earth’s surface more in search of an ideal cold-active protease. The understanding of molecular and mechanistic details of these proteases will open up new avenues to tailor proteases with the desired properties. A detailed account of the developments in the production and applications of cold-active proteases is presented in this review. Full article

(This article belongs to the Special Issue Polar Microbiology: Recent Advances and Future Perspectives)

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13 pages, 251 KiB

Open AccessArticle

A Deeper Statistical Examination of Arrival Dates of Migratory Breeding Birds in Relation to Global Climate Change

by W. Herbert Wilson, Jr.

Department of Biology, Colby College, 5739 Mayflower Hill Drive, Waterville, ME 04901, USA

Biology 2013, 2(2), 742-754; https://doi.org/10.3390/biology2020742 - 26 Apr 2013

Cited by 9 | Viewed by 8467

Abstract

Using an 18-year dataset of arrival dates of 65 species of Maine migratory breeding birds, I take a deeper view of the data to ask questions about the shapes of the distribution. For each year, most species show a consistent right-skewed pattern of [...] Read more.

Using an 18-year dataset of arrival dates of 65 species of Maine migratory breeding birds, I take a deeper view of the data to ask questions about the shapes of the distribution. For each year, most species show a consistent right-skewed pattern of distribution, suggesting that selection is stronger against individuals that arrive too early compared to those that arrive later. Distributions are consistently leptokurtic, indicating a narrow window of optimal arrival dates. Species that arrive earlier in the spring show higher skewness and kurtosis values. Nectarivorous species showed more pronounced skewness. Wintering area did not explain patterns of skewness or kurtosis. Deviations from average temperatures and the North Atlantic Oscillation index explained little variation in skewness and kurtosis. When arrival date distributions are broken down into different medians (e.g., 5% median and 75% median), stronger correlations emerge for portions of the distribution that are adjacent, suggesting species fine-tune the progress of their migration. Interspecific correlations for birds arriving around the same time are stronger for earliest migrants (the 25% median) compared to the true median and the 75% median. Full article

(This article belongs to the Special Issue Biological Implications of Climate Change)

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23 pages, 383 KiB

Open AccessReview

Psychrophily and Catalysis

by Charles Gerday

Laboratory of Biochemistry, Institute of Chemistry, University of Liege, Sart-Tilman, B-4000, Liege, Belgium

Biology 2013, 2(2), 719-741; https://doi.org/10.3390/biology2020719 - 16 Apr 2013

Cited by 48 | Viewed by 9537

Abstract

Polar and other low temperature environments are characterized by a low content in energy and this factor has a strong incidence on living organisms which populate these rather common habitats. Indeed, low temperatures have a negative effect on ectothermic populations since they can [...] Read more.

Polar and other low temperature environments are characterized by a low content in energy and this factor has a strong incidence on living organisms which populate these rather common habitats. Indeed, low temperatures have a negative effect on ectothermic populations since they can affect their growth, reaction rates of biochemical reactions, membrane permeability, diffusion rates, action potentials, protein folding, nucleic acids dynamics and other temperature-dependent biochemical processes. Since the discovery that these ecosystems, contrary to what was initially expected, sustain a rather high density and broad diversity of living organisms, increasing efforts have been dedicated to the understanding of the molecular mechanisms involved in their successful adaptation to apparently unfavorable physical conditions. The first question that comes to mind is: How do these organisms compensate for the exponential decrease of reaction rate when temperature is lowered? As most of the chemical reactions that occur in living organisms are catalyzed by enzymes, the kinetic and thermodynamic properties of cold-adapted enzymes have been investigated. Presently, many crystallographic structures of these enzymes have been elucidated and allowed for a rather clear view of their adaptation to cold. They are characterized by a high specific activity at low and moderate temperatures and a rather low thermal stability, which induces a high flexibility that prevents the freezing effect of low temperatures on structure dynamics. These enzymes also display a low activation enthalpy that renders them less dependent on temperature fluctuations. This is accompanied by a larger negative value of the activation entropy, thus giving evidence of a more disordered ground state. Appropriate folding kinetics is apparently secured through a large expression of trigger factors and peptidyl–prolyl cis/trans-isomerases. Full article

(This article belongs to the Special Issue Polar Microbiology: Recent Advances and Future Perspectives)

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17 pages, 851 KiB

Open AccessArticle

Use of Tetravalent Galabiose for Inhibition of Streptococcus Suis Serotype 2 Infection in a Mouse Model

by Roland J. Pieters^1,*, Hans-Christian Slotved², Hanne Møller Mortensen², Lene Arler², Jukka Finne³, Sauli Haataja⁴, John A. F. Joosten¹, Hilbert M. Branderhorst¹ and Karen A. Krogfelt²

¹ Department of Medicinal Chemistry and Chemical Biology, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, P.O. Box 80082, 3508 TB, Utrecht, The Netherlands

² Department of Microbiology and Infection Control (MI), Statens Serum Institut, Copenhagen, Denmark

³ Department of Biosciences, Division of Biochemistry and Biotechnology, University of Helsinki, P.O.B. 56, Helsinki FI-00014, Finland

⁴ Department of Medical Biochemistry and Genetics, University of Turku, Kiinamyllynkatu 10, Turku FI-20520, Finland

Biology 2013, 2(2), 702-718; https://doi.org/10.3390/biology2020702 - 8 Apr 2013

Cited by 9 | Viewed by 7679

Abstract

Streptococcus suis is an important swine pathogen associated with a variety of infections such as meningitis, arthritis and septicemia. The bacterium is zoonotic and has been found to cause meningitis especially in humans occupationally exposed to infected pigs. Since adhesion is a prerequisite [...] Read more.

Streptococcus suis is an important swine pathogen associated with a variety of infections such as meningitis, arthritis and septicemia. The bacterium is zoonotic and has been found to cause meningitis especially in humans occupationally exposed to infected pigs. Since adhesion is a prerequisite for colonization and subsequent infection, anti-adhesion treatment seems a natural alternative to traditional treatment with antibiotics. In order to optimize the inhibitory potency a multivalency approach was taken in the inhibitor design. A synthetic tetravalent galabiose compound was chosen which had previously shown promising anti-adhesion effects with S. suis in vitro. The aim of this study was to evaluate the in vivo effects of the compound using an infection peritonitis mouse model. As such S. suis serotype 2 infection and treatment were tested in vivo and the effects were compared to the effect of treatment with penicillin. Full article

(This article belongs to the Special Issue Bacterial Adhesion)

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9 pages, 763 KiB

Open AccessArticle

Endolithic Microbial Life in Extreme Cold Climate: Snow Is Required, but Perhaps Less Is More

by Henry J. Sun

Division of Earth and Ecosystem Sciences, Desert Research Institute, Las Vegas, NV 89119, USA

Biology 2013, 2(2), 693-701; https://doi.org/10.3390/biology2020693 - 3 Apr 2013

Cited by 15 | Viewed by 7751

Abstract

Cyanobacteria and lichens living under sandstone surfaces in the McMurdo Dry Valleys require snow for moisture. Snow accumulated beyond a thin layer, however, is counterproductive, interfering with rock insolation, snow melting, and photosynthetic access to light. With this in mind, the facts that [...] Read more.

Cyanobacteria and lichens living under sandstone surfaces in the McMurdo Dry Valleys require snow for moisture. Snow accumulated beyond a thin layer, however, is counterproductive, interfering with rock insolation, snow melting, and photosynthetic access to light. With this in mind, the facts that rock slope and direction control colonization, and that climate change results in regional extinctions, can be explained. Vertical cliffs, which lack snow cover and are perpetually dry, are devoid of organisms. Boulder tops and edges can trap snow, but gravity and wind prevent excessive buildup. There, the organisms flourish. In places where snow-thinning cannot occur and snow drifts collect, rocks may contain living or dead communities. In light of these observations, the possibility of finding extraterrestrial endolithic communities on Mars cannot be eliminated. Full article

(This article belongs to the Special Issue Polar Microbiology: Recent Advances and Future Perspectives)

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42 pages, 422 KiB

Open AccessReview

Predicting the Response of Molluscs to the Impact of Ocean Acidification

by Laura M. Parker^1,*, Pauline M. Ross¹, Wayne A. O'Connor², Hans O. Pörtner³

, Elliot Scanes¹ and John M. Wright¹

¹ School of Science and Health, University of Western Sydney, Hawkesbury K12, Locked Bag 1797, Penrith, Sydney, New South Wales 2751, Australia

² Industry and Investment NSW, Port Stephens Fisheries Centre, Taylors Beach, New South Wales 2316, Australia

³ Alfred Wegener Institute for Polar and Marine Research in the Hermann von Helmholtz Association of National Research Centres e. V. (HGF), Am Handelshafen 12, Bremerhaven, 27570,Germany

Biology 2013, 2(2), 651-692; https://doi.org/10.3390/biology2020651 - 2 Apr 2013

Cited by 293 | Viewed by 26538

Abstract

Elevations in atmospheric carbon dioxide (CO₂) are anticipated to acidify oceans because of fundamental changes in ocean chemistry created by CO₂ absorption from the atmosphere. Over the next century, these elevated concentrations of atmospheric CO₂ are expected to result [...] Read more.

Elevations in atmospheric carbon dioxide (CO₂) are anticipated to acidify oceans because of fundamental changes in ocean chemistry created by CO₂ absorption from the atmosphere. Over the next century, these elevated concentrations of atmospheric CO₂ are expected to result in a reduction of the surface ocean waters from 8.1 to 7.7 units as well as a reduction in carbonate ion (CO₃²⁻) concentration. The potential impact that this change in ocean chemistry will have on marine and estuarine organisms and ecosystems is a growing concern for scientists worldwide. While species-specific responses to ocean acidification are widespread across a number of marine taxa, molluscs are one animal phylum with many species which are particularly vulnerable across a number of life-history stages. Molluscs make up the second largest animal phylum on earth with 30,000 species and are a major producer of CaCO₃. Molluscs also provide essential ecosystem services including habitat structure and food for benthic organisms (i.e., mussel and oyster beds), purification of water through filtration and are economically valuable. Even sub lethal impacts on molluscs due to climate changed oceans will have serious consequences for global protein sources and marine ecosystems. Full article

(This article belongs to the Special Issue Biological Implications of Climate Change)

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22 pages, 528 KiB

Open AccessArticle

Ecology of Subglacial Lake Vostok (Antarctica), Based on Metagenomic/Metatranscriptomic Analyses of Accretion Ice

by Scott O. Rogers^*, Yury M. Shtarkman, Zeynep A. Koçer^†, Robyn Edgar, Ram Veerapaneni^‡ and Tom D'Elia^§

¹ Department of Biological Sciences, Bowling Green State University, Bowling Green, OH 43403, USA

^† Current Address: Department of Infectious Diseases, Division of Virology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA

^‡ Current Address: Department of Biological Sciences, Bowling Green State University, Firelands Campus, Huron, OH 44839, USA

^§ Current Address: Biological Sciences, Indian River State College, 32021 Virginia Avenue, Fort Pierce, FL 34981, USA

Biology 2013, 2(2), 629-650; https://doi.org/10.3390/biology2020629 - 28 Mar 2013

Cited by 37 | Viewed by 19040

Abstract

Lake Vostok is the largest of the nearly 400 subglacial Antarctic lakes and has been continuously buried by glacial ice for 15 million years. Extreme cold, heat (from possible hydrothermal activity), pressure (from the overriding glacier) and dissolved oxygen (delivered by melting meteoric [...] Read more.

Lake Vostok is the largest of the nearly 400 subglacial Antarctic lakes and has been continuously buried by glacial ice for 15 million years. Extreme cold, heat (from possible hydrothermal activity), pressure (from the overriding glacier) and dissolved oxygen (delivered by melting meteoric ice), in addition to limited nutrients and complete darkness, combine to produce one of the most extreme environments on Earth. Metagenomic/metatranscriptomic analyses of ice that accreted over a shallow embayment and over the southern main lake basin indicate the presence of thousands of species of organisms (94% Bacteria, 6% Eukarya, and two Archaea). The predominant bacterial sequences were closest to those from species of Firmicutes, Proteobacteria and Actinobacteria, while the predominant eukaryotic sequences were most similar to those from species of ascomycetous and basidiomycetous Fungi. Based on the sequence data, the lake appears to contain a mixture of autotrophs and heterotrophs capable of performing nitrogen fixation, nitrogen cycling, carbon fixation and nutrient recycling. Sequences closest to those of psychrophiles and thermophiles indicate a cold lake with possible hydrothermal activity. Sequences most similar to those from marine and aquatic species suggest the presence of marine and freshwater regions. Full article

(This article belongs to the Special Issue Polar Microbiology: Recent Advances and Future Perspectives)

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26 pages, 1042 KiB

Open AccessReview

Sea Ice Microorganisms: Environmental Constraints and Extracellular Responses

by Marcela Ewert^* and Jody W. Deming

School of Oceanography, University of Washington, Campus Mailbox 357940, Seattle, WA 98195,USA

Biology 2013, 2(2), 603-628; https://doi.org/10.3390/biology2020603 - 28 Mar 2013

Cited by 112 | Viewed by 13720

Abstract

Inherent to sea ice, like other high latitude environments, is the strong seasonality driven by changes in insolation throughout the year. Sea-ice organisms are exposed to shifting, sometimes limiting, conditions of temperature and salinity. An array of adaptations to survive these and other [...] Read more.

Inherent to sea ice, like other high latitude environments, is the strong seasonality driven by changes in insolation throughout the year. Sea-ice organisms are exposed to shifting, sometimes limiting, conditions of temperature and salinity. An array of adaptations to survive these and other challenges has been acquired by those organisms that inhabit the ice. One key adaptive response is the production of extracellular polymeric substances (EPS), which play multiple roles in the entrapment, retention and survival of microorganisms in sea ice. In this concept paper we consider two main areas of sea-ice microbiology: the physico-chemical properties that define sea ice as a microbial habitat, imparting particular advantages and limits; and extracellular responses elicited in microbial inhabitants as they exploit or survive these conditions. Emphasis is placed on protective strategies used in the face of fluctuating and extreme environmental conditions in sea ice. Gaps in knowledge and testable hypotheses are identified for future research. Full article

(This article belongs to the Special Issue Polar Microbiology: Recent Advances and Future Perspectives)

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16 pages, 174 KiB

Open AccessReview

Antitumor Virotherapy by Attenuated Measles Virus (MV)

by Jean-Baptiste Guillerme^1,2,3, Marc Gregoire^1,2,3, Frédéric Tangy⁴ and Jean-François Fonteneau^1,2,3,*

¹ INSERM, UMR892, Nantes, F-44000, France

² CNRS, UMR6299, Nantes, F-44000, France

³ Université de Nantes, Nantes, F-44000, France

⁴ CNRS, URA3015, Institut Pasteur, Unité de Génomique Virale et Vaccination, Paris, 75015, France

Biology 2013, 2(2), 587-602; https://doi.org/10.3390/biology2020587 - 28 Mar 2013

Cited by 15 | Viewed by 7374

Abstract

Antitumor virotherapy consists of the use of replication-competent viruses to infect and kill tumor cells preferentially, without damaging healthy cells. Vaccine-attenuated strains of measles virus (MV) are good candidates for this approach. Attenuated MV uses the CD46 molecule as a major entry receptor [...] Read more.

Antitumor virotherapy consists of the use of replication-competent viruses to infect and kill tumor cells preferentially, without damaging healthy cells. Vaccine-attenuated strains of measles virus (MV) are good candidates for this approach. Attenuated MV uses the CD46 molecule as a major entry receptor into cells. This molecule negatively regulates the complement system and is frequently overexpressed by cancer cells to escape lysis by the complement system. MV exhibits oncolytic properties in many cancer types in vitro, and in mouse models. Phase I clinical trials using MV are currently underway. Here, we review the state of this therapeutic approach, with a focus on the effects of MV on the antitumor immune response. Full article

(This article belongs to the Special Issue RNA Viruses and Cancer)

32 pages, 635 KiB

Open AccessReview

Dynamic Interplay of Smooth Muscle α-Actin Gene-Regulatory Proteins Reflects the Biological Complexity of Myofibroblast Differentiation

by Arthur Roger Strauch^* and Seethalakshmi Hariharan

Department of Physiology & Cell Biology and the Ohio State Biochemistry Program, the Dorothy M. Davis Heart & Lung Research Institute, The Ohio State University College of Medicine, Columbus, OH 43210, USA

Biology 2013, 2(2), 555-586; https://doi.org/10.3390/biology2020555 - 28 Mar 2013

Cited by 15 | Viewed by 10693

Abstract

Myofibroblasts (MFBs) are smooth muscle-like cells that provide contractile force required for tissue repair during wound healing. The leading agonist for MFB differentiation is transforming growth factor β1 (TGFβ1) that induces transcription of genes encoding smooth muscle α-actin (SMαA) and interstitial collagen that [...] Read more.

Myofibroblasts (MFBs) are smooth muscle-like cells that provide contractile force required for tissue repair during wound healing. The leading agonist for MFB differentiation is transforming growth factor β1 (TGFβ1) that induces transcription of genes encoding smooth muscle α-actin (SMαA) and interstitial collagen that are markers for MFB differentiation. TGFβ1 augments activation of Smad transcription factors, pro-survival Akt kinase, and p38 MAP kinase as well as Wingless/int (Wnt) developmental signaling. These actions conspire to activate β-catenin needed for expression of cyclin D, laminin, fibronectin, and metalloproteinases that aid in repairing epithelial cells and their associated basement membranes. Importantly, β-catenin also provides a feed-forward stimulus that amplifies local TGFβ1 autocrine/paracrine signaling causing transition of mesenchymal stromal cells, pericytes, and epithelial cells into contractile MFBs. Complex, mutually interactive mechanisms have evolved that permit several mammalian cell types to activate the SMαA promoter and undergo MFB differentiation. These molecular controls will be reviewed with an emphasis on the dynamic interplay between serum response factor, TGFβ1-activated Smads, Wnt-activated β-catenin, p38/calcium-activated NFAT protein, and the RNA-binding proteins, Purα, Purβ, and YB-1, in governing transcriptional and translational control of the SMαA gene in injury-activated MFBs. Full article

(This article belongs to the Special Issue Gene Expression and Regulation)

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22 pages, 282 KiB

Open AccessReview

Microbial Competition in Polar Soils: A Review of an Understudied but Potentially Important Control on Productivity

by Terrence H. Bell^1,2, Katrina L. Callender^1,2, Lyle G. Whyte¹ and Charles W. Greer^2,*

¹ Department of Natural Resource Sciences, McGill University, Sainte-Anne-de-Bellevue, Quebec H9X 3V9, Canada

² National Research Council Canada, Energy, Mining and Environment, 6100 Royalmount Avenue, Montreal, Quebec H4P 2R2, Canada

Biology 2013, 2(2), 533-554; https://doi.org/10.3390/biology2020533 - 27 Mar 2013

Cited by 39 | Viewed by 11400

Abstract

Intermicrobial competition is known to occur in many natural environments, and can result from direct conflict between organisms, or from differential rates of growth, colonization, and/or nutrient acquisition. It has been difficult to extensively examine intermicrobial competition in situ, but these interactions [...] Read more.

Intermicrobial competition is known to occur in many natural environments, and can result from direct conflict between organisms, or from differential rates of growth, colonization, and/or nutrient acquisition. It has been difficult to extensively examine intermicrobial competition in situ, but these interactions may play an important role in the regulation of the many biogeochemical processes that are tied to microbial communities in polar soils. A greater understanding of how competition influences productivity will improve projections of gas and nutrient flux as the poles warm, may provide biotechnological opportunities for increasing the degradation of contaminants in polar soil, and will help to predict changes in communities of higher organisms, such as plants. Full article

(This article belongs to the Special Issue Polar Microbiology: Recent Advances and Future Perspectives)

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19 pages, 1940 KiB

Open AccessArticle

Composition, Diversity, and Stability of Microbial Assemblages in Seasonal Lake Ice, Miquelon Lake, Central Alberta

by Anna Bramucci¹, Sukkyun Han^1,†, Justin Beckers², Christian Haas^2,‡ and Brian Lanoil^1,*

¹ Department of Biological Sciences, University of Alberta, Edmonton, AB T6G2E9 Canada

² Department of Earth and Atmospheric Sciences, University of Alberta, Edmonton, AB T6G2E9 Canada

^† Current address: IEH Laboratories and Consulting Group, Lake Forest Park, WA 98155, Canada

^‡ Current address: Department of Earth and Space Science and Engineering, York University, 105 Petrie Science Building, Toronto, ON M3J 1P3, Canada

Biology 2013, 2(2), 514-532; https://doi.org/10.3390/biology2020514 - 27 Mar 2013

Cited by 2 | Viewed by 7924

Abstract

The most familiar icy environments, seasonal lake and stream ice, have received little microbiological study. Bacteria and Eukarya dominated the microbial assemblage within the seasonal ice of Miquelon Lake, a shallow saline lake in Alberta, Canada. The bacterial assemblages were moderately diverse and [...] Read more.

The most familiar icy environments, seasonal lake and stream ice, have received little microbiological study. Bacteria and Eukarya dominated the microbial assemblage within the seasonal ice of Miquelon Lake, a shallow saline lake in Alberta, Canada. The bacterial assemblages were moderately diverse and did not vary with either ice depth or time. The closest relatives of the bacterial sequences from the ice included Actinobacteria, Bacteroidetes, Proteobacteria, Verrucomicrobia, and Cyanobacteria. The eukaryotic assemblages were less conserved and had very low diversity. Green algae relatives dominated the eukaryotic gene sequences; however, a copepod and cercozoan were also identified, possibly indicating the presence of complete microbial loop. The persistence of a chlorophyll a peak at 25–30 cm below the ice surface, despite ice migration and brine flushing, indicated possible biological activity within the ice. This is the first study of the composition, diversity, and stability of seasonal lake ice. Full article

(This article belongs to the Special Issue Polar Microbiology: Recent Advances and Future Perspectives)

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33 pages, 911 KiB

Open AccessArticle

Nonindigenous Plant Advantage in Native and Exotic Australian Grasses under Experimental Drought, Warming, and Atmospheric CO₂ Enrichment

by Robert C. Godfree^*, Bruce C. Robertson, Washington J. Gapare, Miloš Ivković, David J. Marshall, Brendan J. Lepschi and Alexander B. Zwart

CSIRO Plant Industry, GPO Box 1600, Canberra, ACT 2601, Australia

Biology 2013, 2(2), 481-513; https://doi.org/10.3390/biology2020481 - 27 Mar 2013

Cited by 8 | Viewed by 7922

Abstract

A general prediction of ecological theory is that climate change will favor invasive nonindigenous plant species (NIPS) over native species. However, the relative fitness advantage enjoyed by NIPS is often affected by resource limitation and potentially by extreme climatic events such as drought. [...] Read more.

A general prediction of ecological theory is that climate change will favor invasive nonindigenous plant species (NIPS) over native species. However, the relative fitness advantage enjoyed by NIPS is often affected by resource limitation and potentially by extreme climatic events such as drought. Genetic constraints may also limit the ability of NIPS to adapt to changing climatic conditions. In this study, we investigated evidence for potential NIPS advantage under climate change in two sympatric perennial stipoid grasses from southeast Australia, the NIPS Nassella neesiana and the native Austrostipa bigeniculata. We compared the growth and reproduction of both species under current and year 2050 drought, temperature and CO₂ regimes in a multifactor outdoor climate simulation experiment, hypothesizing that NIPS advantage would be higher under more favorable growing conditions. We also compared the quantitative variation and heritability of growth traits in populations of both species collected along a 200 km climatic transect. In contrast to our hypothesis we found that the NIPS N. neesiana was less responsive than A. bigeniculata to winter warming but maintained higher reproductive output during spring drought. However, overall tussock expansion was far more rapid in N. neesiana, and so it maintained an overall fitness advantage over A. bigeniculata in all climate regimes. N. neesiana also exhibited similar or lower quantitative variation and growth trait heritability than A. bigeniculata within populations but greater variability among populations, probably reflecting a complex past introduction history. We found some evidence that additional spring warmth increases the impact of drought on reproduction but not that elevated atmospheric CO₂ ameliorates drought severity. Overall, we conclude that NIPS advantage under climate change may be limited by a lack of responsiveness to key climatic drivers, reduced genetic variability in range-edge populations, and complex drought-CO₂ interactions. Full article

(This article belongs to the Special Issue Biological Implications of Climate Change)

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Biology, Volume 2, Issue 2 (June 2013) – 17 articles , Pages 481-840

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