The Growth and Development of Developmental Biology

The late Ediacaran soft-bodied macroorganism Dickinsonia (age range approx. 560–550 Ma) has often been interpreted as an early animal, and is increasingly invoked in debate on the evolutionary assembly of eumetazoan body plans. However, conclusive positive evidence in support of such a phylogenetic affinity has not been forthcoming. Here we subject a collection of Dickinsonia specimens interpreted to represent multiple ontogenetic stages to a novel, quantitative method for studying growth and development in organisms with an iterative body plan. Our study demonstrates that Dickinsonia grew via pre-terminal ‘deltoidal’ insertion and inflation of constructional units, followed by a later inflation-dominated phase of growth. This growth model is contrary to the widely held assumption that Dickinsonia grew via terminal addition of units at the end of the organism bearing the smallest units. When considered alongside morphological and behavioural attributes, our developmental data phylogenetically constrain Dickinsonia to the Metazoa, specifically the Eumetazoa plus Placozoa total group. Our findings have implications for the use of Dickinsonia in developmental debates surrounding the metazoan acquisition of axis specification and metamerism.

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Col1 and Col2 Gene Expression During the Development of Murine Knee Joints

ASME 2008 Summer Bioengineering Conference, Parts A and B ◽

10.1115/sbc2008-192596 ◽

2008 ◽

Author(s):

Kumar Chokalingam ◽

Chris Frede ◽

Jane L. Florer ◽

Richard J. Wenstrup ◽

David L. Butler

Keyword(s):

Gene Expression ◽

Developmental Biology ◽

Extracellular Matrix ◽

Growth And Development ◽

Normal Growth ◽

Knee Joints ◽

Matrix Gene ◽

Factor Expression ◽

Growth Factor Expression ◽

Ligament Healing

Recently, tissue engineers have turned to developmental biology to try and improve the repair of tendons and ligaments [1]. The premise is that understanding normal growth and development of tendons and ligaments might facilitate in later repair. Understanding these similarities in extracellular matrix gene expression and growth factor expression might allow tissue engineers to develop treatments to augment adult tendon and ligament healing.

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Macromolecules Regulating Growth and Development. The Thirtieth Symposium of the Society for Developmental Biology Held in Seattle, Washington, June 17-19, 1971.Elizabeth D. Hay, Thomas J. King, John Papaconstantinou

The Quarterly Review of Biology ◽

10.1086/408809 ◽

1975 ◽

Vol 50 (4) ◽

pp. 458-459

Keyword(s):

Developmental Biology ◽

Growth And Development ◽

King John

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An ultrastructural study of vegetative incompatibility in plants

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100083047 ◽

1978 ◽

Vol 36 (2) ◽

pp. 436-437

Author(s):

Randy Moore

Keyword(s):

Ultrastructural Study ◽

Cell Walls ◽

Growth And Development ◽

Solanum Pennellii ◽

Initial Product ◽

Basic Aspect ◽

Tissue Interactions ◽

Graft Interface ◽

Antigen Antibody ◽

Standard Fixation

Cell and tissue interactions are a basic aspect of eukaryotic growth and development. While cell-to-cell interactions involving recognition and incompatibility have been studied extensively in animals, there is no known antigen-antibody reaction in plants and the recognition mechanisms operating in plant grafts have been virtually neglected.An ultrastructural study of the Sedum telephoides/Solanum pennellii graft was undertaken to define possible mechanisms of plant graft incompatibility. Grafts were surgically dissected from greenhouse grown plants at various times over 1-4 weeks and prepared for EM employing variations in the standard fixation and embedding procedure. Stock and scion adhere within 6 days after grafting. Following progressive cell senescence in both Sedum and Solanum, the graft interface appears as a band of 8-11 crushed cells after 2 weeks (Fig. 1, I). Trapped between the buckled cell walls are densely staining cytoplasmic remnants and residual starch grains, an initial product of wound reactions in plants.

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The 1-MeV Electron Microscope Installation at the University of Colorado

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100070485 ◽

1973 ◽

Vol 31 ◽

pp. 8-9 ◽

Cited By ~ 1

Author(s):

Mircea Fotino

Keyword(s):

Electron Microscopy ◽

Developmental Biology ◽

Transmission Electron Microscopy ◽

Electron Microscope ◽

National Institutes Of Health ◽

Experimental Program ◽

University Of Colorado ◽

Transmission Electron ◽

The University ◽

Research Resources

A new 1-MeV transmission electron microscope (Model JEM-1000) was installed at the Department of Molecular, Cellular and Developmental Biology of the University of Colorado in Boulder during the summer and fall of 1972 under the sponsorship of the Division of Research Resources of the National Institutes of Health. The installation was completed in October, 1972. It is installed primarily for the study of biological materials without many of the limitations hitherto unavoidable in standard transmission electron microscopy. Only the technical characteristics of the installation are briefly reviewed here. A more detailed discussion of the experimental program under way is being published elsewhere.

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Identification of calcium oxalate crystals in dried or fixed tobacco leaf

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100111550 ◽

1984 ◽

Vol 42 ◽

pp. 288-289

Author(s):

Vicki L. Baliga ◽

Mary Ellen Counts

Keyword(s):

Electron Microscopy ◽

Scanning Electron Microscopy ◽

Calcium Oxalate ◽

Growth And Development ◽

Polarized Light ◽

Calcium Oxalate Crystals ◽

X Ray Diffraction ◽

X Ray ◽

Transmission Electron ◽

Scanning Electron

Calcium is an important element in the growth and development of plants and one form of calcium is calcium oxalate. Calcium oxalate has been found in leaf seed, stem material plant tissue culture, fungi and lichen using one or more of the following methods—polarized light microscopy (PLM), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and x-ray diffraction.Two methods are presented here for qualitatively estimating calcium oxalate in dried or fixed tobacco (Nicotiana) leaf from different stalk positions using PLM. SEM, coupled with energy dispersive x-ray spectrometry (EDS), and powder x-ray diffraction were used to verify that the crystals observed in the dried leaf with PLM were calcium oxalate.

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SEM study of the morphological effects of kinetin and zeatin on the growth and development of the apical meristem in wheat

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100141263 ◽

1995 ◽

Vol 53 ◽

pp. 978-979

Author(s):

G. M. Hutchins ◽

J. S. Gardner

Keyword(s):

Growth And Development ◽

Furfuryl Alcohol ◽

Apical Meristem ◽

Plant Cells ◽

Triticum Aestivum L ◽

Morphological Development ◽

Naturally Occurring ◽

Chinese Spring Wheat ◽

Sem Study ◽

Moist Environment

Cytokinins are plant hormones that play a large and incompletely understood role in the life-cycle of plants. The goal of this study was to determine what roles cytokinins play in the morphological development of wheat. To achieve any real success in altering the development and growth of wheat, the cytokinins must be applied directly to the apical meristem, or spike of the plant. It is in this region that the plant cells are actively undergoing mitosis. Kinetin and Zeatin were the two cytokinins chosen for this experiment. Kinetin is an artificial hormone that was originally extracted from old or heated DNA. Kinetin is easily made from the reaction of adenine and furfuryl alcohol. Zeatin is a naturally occurring hormone found in corn, wheat, and many other plants.Chinese Spring Wheat (Triticum aestivum L.) was used for this experiment. Prior to planting, the seeds were germinated in a moist environment for 72 hours.

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Mechanisms of ethylene biosynthesis and response in plants

Essays in Biochemistry ◽

10.1042/bse0580061 ◽

2015 ◽

Vol 58 ◽

pp. 61-70 ◽

Cited By ~ 11

Author(s):

Paul B. Larsen

Keyword(s):

Plant Growth ◽

Growth And Development ◽

Ethylene Biosynthesis ◽

Unsaturated Hydrocarbon ◽

Flower Senescence ◽

Detailed Knowledge ◽

Plant Growth And Development ◽

Step Process ◽

Ethylene Response ◽

Ethylene Signalling

Ethylene is the simplest unsaturated hydrocarbon, yet it has profound effects on plant growth and development, including many agriculturally important phenomena. Analysis of the mechanisms underlying ethylene biosynthesis and signalling have resulted in the elucidation of multistep mechanisms which at first glance appear simple, but in fact represent several levels of control to tightly regulate the level of production and response. Ethylene biosynthesis represents a two-step process that is regulated at both the transcriptional and post-translational levels, thus enabling plants to control the amount of ethylene produced with regard to promotion of responses such as climacteric flower senescence and fruit ripening. Ethylene production subsequently results in activation of the ethylene response, as ethylene accumulation will trigger the ethylene signalling pathway to activate ethylene-dependent transcription for promotion of the response and for resetting the pathway. A more detailed knowledge of the mechanisms underlying biosynthesis and the ethylene response will ultimately enable new approaches to be developed for control of the initiation and progression of ethylene-dependent developmental processes, many of which are of horticultural significance.

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The Fundamentals of the Clinical Fellowship Experience

Perspectives of the ASHA Special Interest Groups ◽

10.1044/persp1.sig11.81 ◽

2016 ◽

Vol 1 (11) ◽

pp. 81-85

Author(s):

Melanie Hudson

Keyword(s):

Growth And Development ◽

Transition Period ◽

Clinical Skills ◽

Practical Experience ◽

Professional Experience ◽

New Graduate ◽

Independent Practitioner

The Clinical Fellowship Experience is described by the American Speech-Hearing-Language Association (ASHA) as the transition period from constant supervision to independent practitioner. It is typically the first paid professional experience for the new graduate, and may be in a setting with which the new clinician has little or even no significant practical experience. The mentor of a clinical fellow (CF) plays an important role in supporting the growth and development of this new professional in areas that extend beyond application of clinical skills and knowledge. This article discusses how the mentor may provide this support within a framework that facilitates the path to clinical independence.

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