Arabidopsis gynoecium structure in the wild and in ettin mutants

Development ◽  
1995 ◽  
Vol 121 (5) ◽  
pp. 1519-1532 ◽  
Author(s):  
R.A. Sessions ◽  
P.C. Zambryski
Keyword(s):  
Cell Types ◽  
Flowering Plants ◽  
Wild Type ◽  
Reproductive Structure ◽  
Developmental Abnormalities ◽  
Transmitting Tract ◽  
Type Pattern ◽  
In The Wild ◽  
Gynoecium Development ◽  
Scanning Electron

The gynoecium is the female reproductive structure of flowering plants. Here we present a description of the Arabidopsis thaliana gynoecium at anthesis. The cylindrical organ can be broken down into three longitudinal regions arranged in an apical-basal order: stigma, style, and ovary. Each region can be distinguished histologically and morphologically. The transmitting (pollination) tract is axially positioned along the center of the gynoecium and spans stigma, style and ovary. Histochemistry, scanning electron microscopy and a style-specific reporter gene are used to compare the wild-type pattern of gynoecium cell types and regions, with patterns formed in gynoecia of individuals homozygous for a series of allelic mutations at the ETTIN locus. ettin gynoecia show morphological and histological alterations that appear to result from the merging of apical and basal regions and the development of abaxial into adaxial tissues. These developmental abnormalities result in a reduction of the ovary region, an expansion of the stylar and stigmatic regions, and the abaxial (outward) proliferation of transmitting tract tissue. The alterations in the mutants can be interpreted as resulting from misspecifications of position along the longitudinal and transverse axes during gynoecium development. The results suggest that early patterning events underlie wild-type gynoecium development, and that ETT functions during this early programming.

scholarly journals mGluR6 Transcripts in Non-neuronal Tissues

2011 ◽  
Vol 59 (12) ◽  
pp. 1076-1086 ◽  
Author(s):  
Tamar Vardi ◽  
Marie Fina ◽  
Lingli Zhang ◽  
Anuradha Dhingra ◽  
Noga Vardi
Keyword(s):  
Transgenic Mouse ◽  
Metabotropic Glutamate Receptors ◽  
Fluorescent Protein ◽  
Splice Variants ◽  
Subcommissural Organ ◽  
Wild Type Mouse ◽  
Cell Types ◽  
Protein Product ◽  
Wild Type ◽  
In The Wild

To study mGluR6 expression, the authors investigated two transgenic mouse lines that express enhanced green fluorescent protein (GFP) under control of mGluR6 promoter. In retina, GFP was expressed exclusively in all ON bipolar cell types, either uniformly across all cells of this class (line 5) or in a mosaic (patchy) fashion (line 1). In brain, GFP was found in certain cortical areas, superior colliculus, axons of the corpus callosum, accessory olfactory bulb, and cells of the subcommissural organ. Outside the nervous system, GFP was seen in the corneal endothelium, testis, the kidney’s medulla, collecting ducts and parietal layer that surround the glomeruli, and B lymphocytes. Furthermore, RT-PCR showed that most tissues that expressed GFP in the transgenic mouse also transcribed two splice variants of mGluR6 in the wild-type mouse. The alternate variant was lacking exon 8, predicting a protein product of 545 amino acids that lacks the 7-transmembrane domains of the receptor. In cornea, immunostaining for mGluR6 gave strong staining in the endothelium, and this was stronger in wild-type than in mGluR6-null mice. Furthermore, calcium imaging with Fura-2 showed that application of L-AP4, an agonist for group III metabotropic glutamate receptors including mGluR6, elevated calcium in endothelial cells.

Enhanced sodium-dependent extrusion of magnesium in mutant cells established from a mouse renal tubular cell line

2005 ◽  
Vol 289 (4) ◽  
pp. F742-F748 ◽  
Author(s):  
Masaru Watanabe ◽  
Masato Konishi ◽  
Ichiro Ohkido ◽  
Senya Matsufuji
Keyword(s):  
Culture Media ◽  
Cell Types ◽  
Renal Tubular Cell ◽  
Wild Type ◽  
Tubular Cells ◽  
Renal Tubular Cells ◽  
In The Wild ◽  
Renal Tubular ◽  
Mutant Cells ◽  
Very High

To study the regulatory mechanisms of intracellular Mg2+ concentration ([Mg2+]i) in renal tubular cells as well as in other cell types, we established a mutant strain of mouse renal cortical tubular cells that can grow in culture media with very high extracellular Mg2+ concentrations ([Mg2+]o > 100 mM: 101Mg-tolerant cells). [Mg2+]i was measured with a fluorescent indicator furaptra (mag-fura 2) in wild-type and 101Mg-tolerant cells. The average level of [Mg2+]i in the 101Mg-tolerant cells was kept lower than that in the wild-type cells either at 51 mM or 1 mM [Mg2+]o. When [Mg2+]o was lowered from 51 to 1 mM, the decrease in [Mg2+]i was significantly faster in the 101Mg-tolerant cells than in the wild-type cells. These differences between the 101Mg-tolerant cells and the wild-type cells were abolished in the absence of extracellular Na+ or in the presence of imipramine, a known inhibitor of Na+/Mg2+ exchange. We conclude that Na+-dependent Mg2+ transport activity is enhanced in the 101Mg-tolerant cells. The enhanced Mg2+ extrusion may prevent [Mg2+]i increase to higher levels and may be responsible for the Mg2+ tolerance.

Abstract 925: Rit GTPase Protects Cells from Oxidative Damage

Circulation ◽  
2007 ◽  
Vol 116 (suppl_16) ◽  
Author(s):  
Jennifer L Rudolph ◽  
Geng-Xian Shi ◽  
Susan M Harrison ◽  
Douglas A Harrison ◽  
Douglas A Andres
Keyword(s):  
Cortical Neurons ◽  
Map Kinases ◽  
Critical Role ◽  
Cell Types ◽  
Signaling Cascades ◽  
Neuronal Cultures ◽  
Wild Type ◽  
Developmental Abnormalities ◽  
Cellular Survival ◽  
Basic Biology

Signaling cascades that contribute to the regulation of cellular survival influence many cardiovascular diseases. Elucidating the mechanisms of these cascades is thus important for understanding basic biology and for therapeutic intervention. We have identified an evolution-arily conserved group of Ras-related GTPases, including two mammalian genes (Rit and Rin) and a single Drosophila ortholog (Ric), that we hypothesize plays a critical role in trophic factor-mediated anti-apoptotic signaling. Expression of activated Rit in PC6 cells induces potent activation of the MAP kinases ERK1/2 and p38, and promotes neurite outgrowth and cell survival. Furthermore, RNAi-mediated Rit silencing sensitized PC6 cells to a wide variety of stresses, in part by inhibiting NGF-mediated activation of ERK and p38 MAP kinases and CREB. Here we present studies from two genetic models designed to further assess our hypothesis. First, we generated a transgenic mouse over-expressing constitutively activated Rit (RitL79). To begin to assess the contribution of Rit signaling to cellular survival, we examined the ability of cortical neuronal cultures isolated from Rit-TG versus wild-type littermates to survive reactive-oxygen-species (ROS)-mediated cell death. Cell viability for wild-type cortical neurons following a 4 h exposure to H2O2 (60 μM) was reduced approximately 90%, while cortical neurons isolated from Rit-TG mice were largely unaffected by this treatment. Thus, RitL79-mediated signaling protects cortical neurons against ROS-mediated apoptosis. As further confirmation of the important role this protein family plays in survival from stress, we generated a Drosophila strain null for D-Ric. Mutants are homozygous viable and show no obvious developmental abnormalities. However, D-Ric mutants are susceptible to environmental stresses, including heat stress and dry starvation. Taken together, these studies suggest a conserved role for Rit/Ric in promoting cellular survival and suggest that Rit signaling is a potential target for pharmaceutical intervention. We look forward to assessing Rit’s role in other systems including cardiac and vascular cell types. This work was supported by a Predoctoral Fellowship from the AHA.

scholarly journals ThetrpEGene Negatively Regulates Differentiation of Heterocysts at the Level of Induction in Anabaena sp. Strain PCC 7120

2014 ◽  
Vol 197 (2) ◽  
pp. 362-370 ◽  
Author(s):  
Patrick Videau ◽  
Loralyn M. Cozy ◽  
Jasmine E. Young ◽  
Blake Ushijima ◽  
Reid T. Oshiro ◽  
...  
Keyword(s):  
Repeat Sequence ◽  
Mutant Phenotype ◽  
Wild Type ◽  
Content Type ◽  
Type Pattern ◽  
In The Wild ◽  
Anabaena Sp ◽  
Pcc 7120

Levels of 2-oxoglutarate (2-OG) reflect nitrogen status in many bacteria. In heterocystous cyanobacteria, a spike in the 2-OG level occurs shortly after the removal of combined nitrogen from cultures and is an integral part of the induction of heterocyst differentiation. In this work, deletion of one of the two annotatedtrpEgenes inAnabaenasp. strain PCC 7120 resulted in a spike in the 2-OG level and subsequent differentiation of a wild-type pattern of heterocysts when filaments of the mutant were transferred from growth on ammonia to growth on nitrate. In contrast, 2-OG levels were unaffected in the wild type, which did not differentiate under the same conditions. An inverted-repeat sequence located upstream oftrpEbound a central regulator of differentiation, HetR,in vitroand was necessary for HetR-dependent transcription of a reporter fusion and complementation of the mutant phenotypein vivo. Functional complementation of the mutant phenotype with the addition of tryptophan suggested that levels of tryptophan, rather than the demonstrated anthranilate synthase activity of TrpE, mediated the developmental response of the wild type to nitrate. A model is presented for the observed increase in 2-OG in thetrpEmutant.

scholarly journals Identification of cell populations necessary for leaf-to-leaf electrical signaling in a wounded plant

2018 ◽  
Vol 115 (40) ◽  
pp. 10178-10183 ◽  
Author(s):  
Chi Tam Nguyen ◽  
Andrzej Kurenda ◽  
Stéphanie Stolz ◽  
Aurore Chételat ◽  
Edward E. Farmer
Keyword(s):  
Fusion Proteins ◽  
Gene Activation ◽  
Extraction Procedure ◽  
Cell Types ◽  
Cytosolic Calcium ◽  
Wild Type ◽  
Defense Gene ◽  
Sieve Elements ◽  
In The Wild ◽  
Electrical Signaling

The identity of the cell files necessary for the leaf-to-leaf transmission of wound signals plants has been debated for decades. InArabidopsis, wounding initiates the glutamate receptor-like (GLR)–dependent propagation of membrane depolarizations that lead to defense gene activation. Using a vein extraction procedure we found pools of GLR-fusion proteins in endomembranes in phloem sieve elements and/or in xylem contact cells. Strikingly, only double mutants that eliminated GLRs from both of these spatially separated cell types strongly attenuated leaf-to-leaf electrical signaling.glr3.3mutants were also compromised in their defense against herbivores. Since wounding is known to cause increases in cytosolic calcium, we monitored electrical signals and Ca2+transients simultaneously. This revealed that wound-induced membrane depolarizations in the wild-type preceded cytosolic Ca2+maxima. The axial and radial distributions of calcium fluxes were differentially affected in eachglrmutant. Resolving a debate over which cell types are necessary for electrical signaling between leaves, we show that phloem sieve elements and xylem contact cells function together in this process.

Ultrastructure of melanin formation in Verticillium dahliae with (+)-scytalone as a biosynthetic intermediate

1976 ◽  
Vol 22 (5) ◽  
pp. 702-711 ◽  
Author(s):  
M. H. Wheeler ◽  
W. J. Tolmsoff ◽  
S. Meola
Keyword(s):  
Verticillium Dahliae ◽  
Cell Walls ◽  
Maximum Rate ◽  
Melanin Synthesis ◽  
Wild Type ◽  
Type Isolate ◽  
Albino Mutant ◽  
In The Wild ◽  
Fibrillar Network ◽  
Scanning Electron

Transmission and scanning electron microscopy showed that melanin of wild-type Verticillium dahliae occurred as granules in microsclerotial cell walls and in a fibrillar network encapsulating the walls. An albino microsclerotial mutant and a brown microsclerotial mutant of V. dahliae did not form melanin granules. When albino microsclerotia were treated with (+)-scytalone (a metabolite that the brown mutant accumulates), they formed melanin granules and turned black. These granules were similar in appearance and distribution to those in the wild type. Melanin granules of the wild-type isolate and the scytalone-treated albino mutant were formed at a maximum rate in microsclerotia from 5- to 8-day-old cultures. These observations suggest that scytalone is a natural intermediate of melanin synthesis in V. dahliae.

scholarly journals Plasmid recombination in a rad52 mutant of Saccharomyces cerevisiae.

Genetics ◽  
1992 ◽  
Vol 131 (2) ◽  
pp. 261-276 ◽  
Author(s):  
K J Dornfeld ◽  
D M Livingston
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Inverted Repeat ◽  
Wild Type Strain ◽  
Direct Repeat ◽  
Cell Types ◽  
Wild Type ◽  
Plasmid Recombination ◽  
Intramolecular Recombination ◽  
In The Wild ◽  
Repeat Events

Abstract Using plasmids capable of undergoing intramolecular recombination, we have compared the rates and the molecular outcomes of recombination events in a wild-type and a rad52 strain of Saccharomyces cerevisiae. The plasmids contain his3 heteroalleles oriented in either an inverted or a direct repeat. Inverted repeat plasmids recombine approximately 20-fold less frequently in the mutant than in the wild-type strain. Most events from both cell types have continuous coconversion tracts extending along one of the homologous segments. Reciprocal exchange occurs in fewer than 30% of events. Direct repeat plasmids recombine at rates comparable to those of inverted repeat plasmids in wild-type cells. Direct repeat conversion tracts are similar to inverted repeat conversion tracts in their continuity and length. Inverted and direct repeat plasmid recombination differ in two respects. First, rad52 does not affect the rate of direct repeat recombination as drastically as the rate of inverted repeat recombination. Second, direct repeat plasmids undergo crossing over more frequently than inverted repeat plasmids. In addition, crossovers constitute a larger fraction of mutant than wild-type direct repeat events. Many crossover events from both cell types are unusual in that the crossover HIS3 allele is within a plasmid containing the parental his3 heteroalleles.

Combinatorial control of touch receptor neuron expression in Caenorhabditis elegans

Development ◽  
1993 ◽  
Vol 119 (3) ◽  
pp. 773-783 ◽  
Author(s):  
S. Mitani ◽  
H. Du ◽  
D.H. Hall ◽  
M. Driscoll ◽  
M. Chalfie
Keyword(s):  
Caenorhabditis Elegans ◽  
Cell Types ◽  
Wild Type ◽  
Negative Regulators ◽  
C Elegans ◽  
Combinatorial Control ◽  
Touch Receptor Neurons ◽  
In The Wild ◽  
Receptor Neurons ◽  
Touch Receptor Neuron

Six touch receptor neurons with distinctive morphological features sense gentle touch in Caenorhabditis elegans. Previous studies have identified three genes (lin-32, unc-86 and mec-3) that regulate touch cell development. However, since other cell types also require these genes, we suspected that other genes help restrict the expression of touch cell characteristics to the six neurons seen in the wild type. To identify such genes, we have examined mutants defective in genes required for the development of other C. elegans cells for changes in the pattern of touch cell-specific features. Mutations in seven genes either reduce (lin-14) or increase (lin-4, egl-44, egl-46, sem-4, ced-3 and ced-4) the number of touch receptor-like cells. The combinatorial action of these genes, all of which are required for the production of many cell types, restrict the number of cells expressing touch receptor characteristics in wild-type animals by acting as positive and negative regulators and by removing cells by programmed cell death.

Patterns in Dictyostelium discoideum: the role of myosin II in the transition from the unicellular to the multicellular phase

1993 ◽  
Vol 104 (2) ◽  
pp. 457-466 ◽  
Author(s):  
S. Eliott ◽  
G.H. Joss ◽  
A. Spudich ◽  
K.L. Williams
Keyword(s):  
Dictyostelium Discoideum ◽  
Myosin Ii ◽  
Morphological Development ◽  
Scanning Electron Micrographs ◽  
Wild Type ◽  
Null Cell ◽  
Cell Movements ◽  
In The Wild ◽  
Scanning Electron

Dictyostelium discoideum amoebae which lack the myosin II gene are motile and aggregate to form rudimentary mounds, but do not undergo further morphological development (Manstein et al., 1989). Here we use scanning electron microscopy, light microscopy, immunofluorescence and computer analysis of time-lapse video films to study how D. discoideum myosin null cells of strains HS2205 and HS2206 aggregate. Myosin null cells are sufficiently coordinated in their movements to form two-dimensional aggregation streams, although mutant cells within streams lack the elongated shape and parallel orientation of wild-type strains. In the wild-type, cell movements are coordinated, cells usually joining streams that spiral inwards and upwards as the mound extends into the standing papilla. In the aggregates of mutant strains, cell movements are chaotic, only occasionally forming short-term spirals that rotate at less than half the speed of wild-type spirals and frequently change direction. Unlike the situation in the wild-type where spirals continue with mound elongation, cells within the mutant mound eventually cease translocation altogether as the terminal shape of the mound is reached and only intracellular particle movement is observed. Scanning electron micrographs show that the surface of the wild-type mound consists of flattened cells which fit neatly together. The myosin null cell mound has an uneven surface, the orientation of the cells is chaotic and no tip is formed. This is consistent with the results of synergy experiments in which myosin null cells were absent from the tips of chimeric HS2205/AX2 slugs and pre-culminates. Immunofluorescence microscopy using prespore and spore cell markers reveals that a prestalk/prespore pattern forms within the mutant mound but that terminal spore differentiation is incomplete. These results are discussed in relation to the role of myosin II in aggregation and morphogenesis.

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