scholarly journals Fungi and fungal interactions in the Rhynie chert: a review of the evidence, with the description of Perexiflasca tayloriana gen. et sp. nov. †

2017 ◽  
Vol 373 (1739) ◽  
pp. 20160500 ◽  
Author(s):  
Michael Krings ◽  
Carla J. Harper ◽  
Edith L. Taylor
Keyword(s):  
Three Dimensional ◽  
Terrestrial Ecosystem ◽  
Land Plant ◽  
Biological Degradation ◽  
Microbial Life ◽  
Plant Parts ◽  
Comprehensive Information ◽  
Rhynie Chert ◽  
Fungal Associations ◽  
Fungal Interactions

The Lower Devonian Rhynie chert is one of the most important rock deposits yielding comprehensive information on early continental plant, animal and microbial life. Fungi are especially abundant among the microbial remains, and include representatives of all major fungal lineages except Basidiomycota. This paper surveys the evidence assembled to date of fungal hyphae, mycelial cords and reproductive units (e.g. spores, sporangia, sporocarps), and presents examples of fungal associations and interactions with land plants, other fungi, algae, cyanobacteria and animals from the Rhynie chert. Moreover, a small, chytrid-like organism that occurs singly, in chain-like, linear arrangements, planar assemblages and three-dimensional aggregates of less than 10 to individuals in degrading land plant tissue in the Rhynie chert is formally described, and the name Perexiflasca tayloriana proposed for the organism. Perexiflasca tayloriana probably colonized senescent or atrophied plant parts and participated in the process of biological degradation. The fungal fossils described to date from the Rhynie chert constitute the largest body of structurally preserved evidence of fungi and fungal interactions from any rock deposit, and strongly suggest that fungi played important roles in the functioning of the Early Devonian Rhynie ecosystem. This article is part of a discussion meeting issue ‘The Rhynie cherts: our earliest terrestrial ecosystem revisited’.

scholarly journals History and contemporary significance of the Rhynie cherts—our earliest preserved terrestrial ecosystem

2017 ◽  
Vol 373 (1739) ◽  
pp. 20160489 ◽  
Author(s):  
Dianne Edwards ◽  
Paul Kenrick ◽  
Liam Dolan
Keyword(s):  
Terrestrial Ecosystem ◽  
Analytical Techniques ◽  
Land Plant ◽  
Life Cycles ◽  
Systems Science ◽  
Developmental Genetics ◽  
Earth Systems ◽  
Plant Life ◽  
Rhynie Chert ◽  
Tissue Systems

The Rhynie cherts Unit is a 407 million-year old geological site in Scotland that preserves the most ancient known land plant ecosystem, including associated animals, fungi, algae and bacteria. The quality of preservation is astonishing, and the initial description of several plants 100 years ago had a huge impact on botany. Subsequent discoveries provided unparalleled insights into early life on land. These include the earliest records of plant life cycles and fungal symbioses, the nature of soil microorganisms and the diversity of arthropods. Today the Rhynie chert (here including the Rhynie and Windyfield cherts) takes on new relevance, especially in relation to advances in the fields of developmental genetics and Earth systems science. New methods and analytical techniques also contribute to a better understanding of the environment and its organisms. Key discoveries are reviewed, focusing on the geology of the site, the organisms and the palaeoenvironments. The plants and their symbionts are of particular relevance to understanding the early evolution of the plant life cycle and the origins of fundamental organs and tissue systems. The Rhynie chert provides remarkable insights into the structure and interactions of early terrestrial communities, and it has a significant role to play in developing our understanding of their broader impact on Earth systems. This article is part of a discussion meeting issue ‘The Rhynie cherts: our earliest terrestrial ecosystem revisited’.

scholarly journals Bilaterally symmetric axes with rhizoids composed the rooting structure of the common ancestor of vascular plants

2017 ◽  
Vol 373 (1739) ◽  
pp. 20170042 ◽  
Author(s):  
Alexander J. Hetherington ◽  
Liam Dolan
Keyword(s):  
Vascular Plants ◽  
Common Ancestor ◽  
Terrestrial Ecosystem ◽  
Bilateral Symmetry ◽  
Land Plant ◽  
Land Plants ◽  
Free Living ◽  
Rhynie Chert ◽  
The Common ◽  
Almost All

There are two general types of rooting systems in extant land plants: gametophyte rhizoids and sporophyte root axes. These structures carry out the rooting function in the free-living stage of almost all land plant gametophytes and sporophytes, respectively. Extant vascular plants develop a dominant, free-living sporophyte on which roots form, with the exception of a small number of taxa that have secondarily lost roots. However, fossil evidence indicates that early vascular plants did not develop sporophyte roots. We propose that the common ancestor of vascular plants developed a unique rooting system—rhizoidal sporophyte axes. Here we present a synthesis and reinterpretation of the rootless sporophytes of Horneophyton lignieri , Aglaophyton majus , Rhynia gwynne-vaughanii and Nothia aphylla preserved in the Rhynie chert. We show that the sporophyte rooting structures of all four plants comprised regions of plagiotropic (horizontal) axes that developed unicellular rhizoids on their underside. These regions of axes with rhizoids developed bilateral symmetry making them distinct from the other regions which were radially symmetrical. We hypothesize that rhizoidal sporophyte axes constituted the rooting structures in the common ancestor of vascular plants because the phylogenetic positions of these plants span the origin of the vascular lineage. This article is part of a discussion meeting issue ‘The Rhynie cherts: our earliest terrestrial ecosystem revisited’.

scholarly journals A microscopic approach to investigate bacteria under in situ conditions in sea-ice samples

2001 ◽  
Vol 33 ◽  
pp. 304-310 ◽  
Author(s):  
Karen Junge ◽  
Christopher Krembs ◽  
Jody Deming ◽  
Aaron Stierle ◽  
Hajo Eicken
Keyword(s):  
Sea Ice ◽  
Pore Space ◽  
Three Dimensional ◽  
Epifluorescence Microscopy ◽  
Microbial Populations ◽  
Microbial Life ◽  
Dimensional Network ◽  
In Situ Conditions ◽  
Fluorescent Stain

AbstractMicrobial populations and activity within sea ice have been well described based on bulk measurements from melted sea-ice samples. However, melting destroys the micro-environments within the ice matrix and does not allow for examination of microbial populations at a spatial scale relevant to the organism. Here, we describe the development of a new method allowing for microscopic observations of bacteria localized within the three-dimensional network of brine inclusions in sea ice under in situ conditions. Conventional bacterial staining procedures, using the DNA-specific fluorescent stain DAPI, epifluorescence microscopy and image analysis, were adapted to examine bacteria and their associations with various surfaces within microtomed sections of sea ice at temperatures from −2° to −15°C. The utility and sensitivity of the method were demonstrated by analyzing artificial sea-ice preparations of decimal dilutions of a known bacterial culture. When applied to natural, particle-rich sea ice, the method allowed distinction between bacteria and particles at high magnification. At lower magnifications, observations of bacteria could be combined with those of other organisms and with morphology and particle content of the pore space. The method described here may ultimately aid in discerning constraints on microbial life at extremely low temperatures.

Fungi from the Rhynie chert: a view from the dark side

2003 ◽  
Vol 94 (4) ◽  
pp. 457-473 ◽  
Author(s):  
T. N. Taylor ◽  
S. D. Klavins ◽  
M. Krings ◽  
E. L. Taylor ◽  
H. Kerp ◽  
...  
Keyword(s):  
Fossil Record ◽  
Molecular Data ◽  
Host Responses ◽  
Dark Side ◽  
Early Devonian ◽  
Mycorrhizal Associations ◽  
Rhynie Chert ◽  
Complex Ecosystem ◽  
Taxonomic Groups ◽  
Fungal Interactions

ABSTRACTThe exquisite preservation of organisms in the Early Devonian Rhynie chert ecosystem has permitted the documentation of the morphology and life history biology of fungi belonging to several major taxonomic groups (e.g., Chytridiomycota, Ascomycota, Glomeromycota). The Rhynie chert also provides the first unequivocal evidence in the fossil record of fungal interactions that can in turn be compared with those in modern ecosystems. These interactions in the Rhynie chert involve both green algae and macroplants, with examples of saprophytism, parasitism, and mutualism, including the earliest mycorrhizal associations and lichen symbiosis known to date in the fossil record. Especially significant are several types of specific host responses to fungal infection that indicate that these plants had already evolved methods of defence similar and perhaps analogous to those of extant plants. This suggests that mechanisms underlying the establishment and sustenance of associations of fungi with land plants were well in place prior to the Early Devonian. In addition, a more complete understanding of the microbial organisms involved in this complex ecosystem can also provide calibration points for phylogenies based on molecular data analysis. The richness of the microbial community in the Rhynie chert holds tremendous potential for documenting additional fungal groups, which permits speculation about further interactions with abiotic and biotic components of the environment.

scholarly journals Microfossils from the Lower Devonian Rhynie Chert with suggested affinities to the peronosporomycetes

2012 ◽  
Vol 86 (2) ◽  
pp. 358-367 ◽  
Author(s):  
Michael Krings ◽  
Thomas N. Taylor ◽  
Edith L. Taylor ◽  
Hans Kerp ◽  
Hagen Hass ◽  
...  
Keyword(s):  
Lower Devonian ◽  
Microbial Mats ◽  
Plant Litter ◽  
Microbial Life ◽  
Opaque Material ◽  
New Information ◽  
Single Form ◽  
Rhynie Chert ◽  
Thin Walled ◽  
Size And Morphology

A conspicuous silicified microfossil, Frankbaronia polyspora n. gen. n. sp., occurs in plant litter and as an inhabitant of microbial mats from the Lower Devonian Rhynie chert, Aberdeenshire, Scotland. Specimens are elongate-cylindrical, oval, or spherical, thin-walled, and may possess conical or column-like surface projections. Most specimens occur isolated, some are arranged in pairs or short chains. Each specimen contains several small spheres, each in turn with a (sub)centric opaque inclusion. Immature specimens indicate that ontogenesis in this fossil includes the formation of a single centric body of opaque material that subsequently is apportioned among the developing small spheres. Frankbaronia polyspora is quite similar in size and morphology to the oogonia containing oospores seen in certain extant members of the Peronosporomycetes. The Rhynie chert is known to contain the oldest fossil evidence of the Peronosporomycetes but only a single form (Hassiella monospora) has previously been documented. The discovery of a second putative representative of this group of organisms proves that this paleoecosystem is still an important source of new information on the paleodiversity of microbial life.

scholarly journals Identification ofypqPas a New Bacillus subtilis Biofilm Determinant That Mediates the Protection of Staphylococcus aureus against Antimicrobial Agents in Mixed-Species Communities

2014 ◽  
Vol 81 (1) ◽  
pp. 109-118 ◽  
Author(s):  
Pilar Sanchez-Vizuete ◽  
Dominique Le Coq ◽  
Arnaud Bridier ◽  
Jean-Marie Herry ◽  
Stéphane Aymerich ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Bacillus Subtilis ◽  
Extracellular Polymeric Substances ◽  
Antimicrobial Agents ◽  
Three Dimensional ◽  
Laboratory Strain ◽  
Spatial Arrangement ◽  
Content Type ◽  
Microbial Life ◽  
Multispecies Biofilms

ABSTRACTIn most habitats, microbial life is organized in biofilms, three-dimensional edifices sustained by extracellular polymeric substances that enable bacteria to resist harsh and changing environments. Under multispecies conditions, bacteria can benefit from the polymers produced by other species (“public goods”), thus improving their survival under toxic conditions. A recent study showed that aBacillus subtilishospital isolate (NDmed) was able to protectStaphylococcus aureusfrom biocide action in multispecies biofilms. In this work, we identifiedypqP, a gene whose product is required in NDmed for thick-biofilm formation on submerged surfaces and for resistance to two biocides widely used in hospitals. NDmed andS. aureusformed mixed biofilms, and both their spatial arrangement and pathogen protection were mediated by YpqP. FunctionalypqPis present in other naturalB. subtilisbiofilm-forming isolates. However, the gene is disrupted by the SPβ prophage in the weak submerged-biofilm-forming strains NCIB3610 and 168, which are both less resistant than NDmed to the biocides tested. Furthermore, in a 168 laboratory strain cured of the SPβ prophage, the reestablishment of a functionalypqPgene led to increased thickness and resistance to biocides of the associated biofilms. We therefore propose that YpqP is a new and important determinant ofB. subtilissurface biofilm architecture, protection against exposure to toxic compounds, and social behavior in bacterial communities.

scholarly journals Structurally preserved fungi from Antarctica: diversity and interactions in late Palaeozoic and Mesozoic polar forest ecosystems

2016 ◽  
Vol 28 (3) ◽  
pp. 153-173 ◽  
Author(s):  
Carla J. Harper ◽  
Thomas N. Taylor ◽  
Michael Krings ◽  
Edith L. Taylor
Keyword(s):  
Forest Ecosystems ◽  
Research Effort ◽  
Reproductive Organs ◽  
Systematic Position ◽  
Saprotrophic Fungi ◽  
Light Regimes ◽  
The Past ◽  
Late Palaeozoic ◽  
Fungal Associations ◽  
Fungal Interactions

AbstractChert and silicified wood from the Permian through Cretaceous of Antarctica contain abundant information on fungal diversity and plant–fungal interactions. The chert deposits represent a particularly interesting setting for the study of plant–fungal interactions because they preserve remains of distinctive high latitude forest ecosystems with polar light regimes that underwent a profound climate change from icehouse to greenhouse conditions. Moreover, some of the cherts and wood show the predominance of extinct groups of seed plants (e.g. Glossopteridales, Corystospermales). Over the past 30 years, documentation of fossil fungi from Antarctica has shifted from a by-product of plant descriptive studies to a focused research effort. This paper critically reviews the published record of fungi and fungal associations and interactions in the late Palaeozoic and Mesozoic cherts and silicified wood from Antarctica; certain fungal palynomorphs and fungal remains associated with adpression fossils and cuticles are also considered. Evidence of mutualistic (mycorrhizal), parasitic and saprotrophic fungi associated with plant roots, stems, leaves and reproductive organs is presented, together with fungi occurring within the peat matrix and animal–fungus interactions. Special attention is paid to the morphology of the fungi, their systematic position and features that can be used to infer fungal nutritional modes.

Phosphorus Uptake and Utilization by Tree Seedlings

1977 ◽  
Vol 25 (6) ◽  
pp. 571 ◽  
Author(s):  
NJ Barrow
Keyword(s):  
Phosphorus Uptake ◽  
Three Dimensional ◽  
Root Hairs ◽  
Trifolium Subterraneum ◽  
Unit Weight ◽  
Tree Seedlings ◽  
Native Forest ◽  
Eucalyptus Marginata ◽  
Relative Growth ◽  
Plant Parts

Seedlings of five native forest species and of Pinus radiata D. Don were grown in pots in a forest soil at a range of levels of added phosphate for up to 20 weeks. At intervals of 3 weeks, roots were examined for root hairs and mycorrhizas and the weights of plant parts and their phosphorus contents were measured. Components of growth and response were calculated from three-dimensional surfaces which had level of phosphate and time as the independent variables. Except for Banksia grandis Willd., the species responded to phosphate but the time at which the response appeared was affected by seed reserves of phosphorus. Thus response appeared much earlier for the small-seeded Eucalyptus divevsicolor F. Muell. and Acacia pulchella R. Br. than for the large-seeded Eucalyptus calophylla R. Br. and Eucalyptus marginata Donn. ex Sm. The absence of a response by the banksia seemed to arise because of a large seed reserve of phosphorus, a low relative growth rate and a very low concentration of phosphorus in the leaves for maximum photosynthesis. The rates of uptake of phosphorus per unit weight of roots were generally low but increased at a time coincident with the development of mycorrhizas. Relative growth rates and the net assimilation rates were also low and reached maximum values at low concentrations of phosphorus in the leaf. The outcome was that the level of applied phosphate needed for good early growth did not differ greatly from that of Trifolium subterraneum L.

scholarly journals Early Detection of Fetal Abnormality

2013 ◽  
Vol 7 (1) ◽  
pp. 46-50
Author(s):  
Ritsuko K Pooh
Keyword(s):  
Early Detection ◽  
High Frequency ◽  
Obstet Gynecol ◽  
Three Dimensional ◽  
First Trimester ◽  
Two Dimensional ◽  
Fetal Abnormality ◽  
Fetal Abnormalities ◽  
Comprehensive Information ◽  
Vaginal Transducer

ABSTRACT After introduction of high-frequency vaginal transducer, transvaginal two-dimensional ultrasound has established a field of sonoembryology and most of the major fetal abnormalities have been detectable in the first trimester. Three-dimensional ultrasound adds an objective and comprehensive information to two-dimensional sonographic findings. How to cite this article Pooh RK. Early Detection of Fetal Abnormality. Donald School J Ultrasound Obstet Gynecol 2013;7(1):46-50.

Sign in / Sign up

Export Citation Format

Share Document