In vitro ectomycorrhiza formation by monokaryotic and dikaryotic isolates of Pisolithus microcarpus in Eucalyptus grandis

The formation of ectomycorrhizas by monokaryotic and dikaryotic isolates of Pisolithus microcarpus (Cooke & Massee) G. Cunn. in Eucalyptus grandis W. Hill ex Maid. was studied by in vitro synthesis in Petri dishes. The formation of ectomycorrhizas was observed for all strains tested. Ectomycorrhizas formed by the monokaryotic strains presented a sheath of hyphae around the roots and a Hartig net limited to the epidermis layer, typical of the angiosperm ectomycorrhizas. Colonization rates, a measure of the number of ectomycorrhizas in relation to the total number of lateral root tips, varied from 23 to 62%. Some monokaryotic strains stimulated the formation of lateral roots, promoting increases of up to 109% above the control. The presence of some of the isolates in the in vitro synthesis medium stimulated the production of thicker lateral root tips. The dimensions of the lateral roots tips and ectomycorrhizas varied from one isolate to the next, indicating a variation in their capacity to provoke morphological changes in the host plant roots. The dikaryotic strain M5M11 presented higher values for lateral root yield, number of ectomycorrhizas, and colonization percentage than the corresponding monokaryotic strains, M5 and M11. This indicated the possibility of selecting compatible performing monokaryotic isolates for the yield of superior dikaryotic strains. The set of monokaryotic strains tested varied greatly in their ability to colonize E. grandis roots and cause secondary metabolism-related morphological changes in roots, providing a wealth of model systems for the study of genetic, physiological, and morphogenetic processes involved in Pisolithus-Eucalyptus ectomycorrhiza formation.

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Temperature Effects on Absorption and Translocation of Trifluralin and Methazole in Peanuts

Weed Science ◽

10.1017/s0043174500035669 ◽

1972 ◽

Vol 20 (4) ◽

pp. 285-289 ◽

Cited By ~ 15

Author(s):

K. Hawxby ◽

E. Basler ◽

P. W. Santelmann

Keyword(s):

Temperature Effects ◽

Lateral Root ◽

Initial Rate ◽

Lateral Roots ◽

Leaf Tissue ◽

Root Tips ◽

Plant Parts ◽

Tap Root ◽

Rate Of Absorption ◽

Nutrient Solutions

The absorption and translocation of14C-labeled α,α,α-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine (trifluralin) and 2-(3,4-dichlorophenyl)-4-methyl-1,2,4-oxadiazolidine-3,5-dione methazole from nutrient solutions of various temperatures by(Arachis hypogaeaL. ‘Starr’) seedlings were determined. The accumulation of trifluralin in roots at 24 hr after exposure to trifluralin was greatest at 21 C and decreased at higher temperatures up to 38 C. The amounts of trifluralin translocated and accumulated in hypocotyls, tops, and cotyledons were small but generally increased with temperature. The initial rate of absorption of trifluralin was greater in excised lateral root tips than in tap root tips, but there was a greater accumulation in excised tap roots at 24 hr. The initial rates of absorption were higher for excised lateral roots at high temperatures. Total absorption of trifluralin at equilibrium was not proportional to the initial rates of absorption but was highest at low (21 C) and high (38 C) temperatures for excised lateral roots. The absorption of methazole by roots and translocation to other plant parts increased linearly with temperature, and it tended to accumulate in the mature leaf tissue.

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Expression Studies on AUX1-like Genes in Medicago truncatula Suggest That Auxin Is Required at Two Steps in Early Nodule Development

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi.2001.14.3.267 ◽

2001 ◽

Vol 14 (3) ◽

pp. 267-277 ◽

Cited By ~ 86

Author(s):

Françoise de Billy ◽

Cathy Grosjean ◽

Sean May ◽

Malcolm Bennett ◽

Julie V. Cullimore

Keyword(s):

Medicago Truncatula ◽

Lateral Root ◽

Sequence Similarity ◽

Lateral Roots ◽

Peripheral Region ◽

Nodule Development ◽

Central Position ◽

Root Tips ◽

High Sequence Similarity ◽

Primary Roots

Medicago truncatula contains a family of at least five genes related to AUX1 of Arabidopsis thaliana (termed MtLAX genes for Medicago truncatula-like AUX1 genes). The high sequence similarity between the encoded proteins and AUX1 implies that the MtLAX genes encode auxin import carriers. The MtLAX genes are expressed in roots and other organs, suggesting that they play pleiotropic roles related to auxin uptake. In primary roots, the MtLAX genes are expressed preferentially in the root tips, particularly in the provascular bundles and root caps. During lateral root and nodule development, the genes are expressed in the primordia, particularly in cells that were probably derived from the pericycle. At slightly later stages, the genes are expressed in the regions of the developing organs where the vasculature arises (central position for lateral roots and peripheral region for nodules). These results are consistent with MtLAX being involved in local auxin transport and suggest that auxin is required at two common stages of lateral root and nodule development: development of the primordia and differentiation of the vasculature.

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Structure-function analysis of anaphase spindle elongation using isolated diatom spindles

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100085332 ◽

1991 ◽

Vol 49 ◽

pp. 206-207

Author(s):

W. Z. Cande ◽

C.J. Hogan ◽

M. Lee

Keyword(s):

Morphological Changes ◽

Function Analysis ◽

Light And Electron Microscopy ◽

Near Neighbor ◽

Model Systems ◽

Central Spindle ◽

Spindle Poles ◽

Spindle Elongation ◽

Anaphase B

Diatom spindles are important model systems for describing the morphological changes associated with anaphase chromosome movement because the fibrous systems responsible for anaphase A (chromosome-to-pole movement) and anaphase B (spindle elongation) are spatially separate and the central spindle is a paracrystalline array of microtubules. The diatom central spindle, which is responsible for anaphase B, is constructed of two sets of interdigiting microtubules that originate from plate-like spindle poles and display specific near-neighbor interactions in the zone of microtubule overlap. The microtubules of each half-spindle are of relatively unifrom length such that the plus ends are clustered together in narrow zones at each edge of the zone of microtubule overlap. This has allowed us to monitor changes in extent of microtubule overlap in the light microscope with polarization optics. We have isolated spindles from synchronized populations of several species of dividing diatom cells to study the mechanochemistry of anaphase spindle elongation in vitro and to analyze the rearrangement of spindle components by light and electron microscopy during reactivation.

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Induction of Lateral Root Structure Formation on Petunia Roots: A Novel Effect of GMI1000 Ralstonia solanacearum Infection Impaired in Hrp Mutants

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi-19-0597 ◽

2006 ◽

Vol 19 (6) ◽

pp. 597-606 ◽

Cited By ~ 23

Author(s):

Lena Zolobowska ◽

Frédérique Van Gijsegem

Keyword(s):

Ralstonia Solanacearum ◽

Lateral Root ◽

Plant Pathogens ◽

Lateral Roots ◽

Root Tips ◽

Whole Plant ◽

Systemic Spread ◽

Mutant Strains ◽

Architecture Development ◽

Lateral Structures

Ralstonia solanacearum is a soilborne plant pathogen that invades its host via roots. As in many gram-negative bacterial plant pathogens, the R. solanacearum Hrp type III secretion system is essential for interactions of the bacterium with plants; however, the related mechanisms involved in disease expression are largely unknown. In this work, we examined the effects of infection by R. solanacearum GMI1000 and Hrp mutants on the root system of petunia plants. Both the wild-type and mutant strains disturbed the petunia root architecture development by inhibiting lateral root elongation and provoking swelling of the root tips. In addition, GMI100 but not the Hrp mutants induced the formation of new root lateral structures (RLS). This ability is shared by other, but not all, R. solanacearum strains tested. Like lateral roots, these new structures arise from divisions of pericycle founder cells which, nevertheless, exhibit an abnormal morphology. These RLS are efficient colonization sites allowing extensive bacterial multiplication. However, they are not required for the bacterial vascular invasion that leads to the systemic spread of the bacterium through the whole plant, indicating that, instead, they might play a role in the rhizosphere-related stages of the R. solanacearum life cycle.

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FRI0369 MIMICKING GLUCOCORTICOID-INDUCED OSTEOPOROSIS USING AN IN VITRO TRABECULAR HUMAN BONE MODEL

Annals of the Rheumatic Diseases ◽

10.1136/annrheumdis-2020-eular.2569 ◽

2020 ◽

Vol 79 (Suppl 1) ◽

pp. 782.1-782

Author(s):

A. Lang ◽

K. Diesing ◽

A. Damerau ◽

S. Uzun ◽

M. Pfeiffenberger ◽

...

Keyword(s):

Morphological Changes ◽

Human Bone ◽

Model Systems ◽

Bone Homeostasis ◽

Perfusion System ◽

Cultivation Conditions ◽

Bone Model ◽

Long Term Treatment ◽

Biomechanical Stimuli

Background:The bone matrix consists of inorganic and organic components and a variety of specialized cells such as osteoblasts, osteocytes and osteoclasts. The bone-forming osteoblasts are responsible for the production of organic matrix components; they differentiate later into osteocytes which is accompanied by matrix mineralization. Osteoclasts are multinuclear giant cells, which resorb bone. Healthy bone homeostasis is characterized by a balanced, dynamic and continuous remodeling process. Glucocorticoids (GCs) are commonly used to successfully treat patients with inflammatory rheumatic and other autoimmune diseases. However, long-term treatment with GC can potentially lead to several adverse effects such as the inhibition of osteoblast proliferation and the increase of osteoclastic activity resulting in osteoporosis.Objectives:Hence, the aim of our project is to i) develop anin vitrotrabecular human bone model, ii) integrate this bone model into a perfusion system to accelerate mineralization and provide biomechanical stimuli and iii) applying prednisolone to induce osteoporosis. Here we present our initial results describing the successful differentiation of osteoblasts and osteoclasts in a 3D environment, and the accomplished integration of the bone model into a perfusion system.Methods:In a first step, different cultivation conditions were tested to allow optimal osteogenic or osteoclastic differentiation. To this end, a) human bone marrow derived mesenchymal stromal cells (hMSCs) were treated with osteogenic medium, and b) monocytes (isolated from buffy coats) were differentiated into osteoclasts using following protocol: incubation for 3 days with 25 ng/ml M-CSF followed by an 18-day incubation with M-CSF and 50 ng/ml RANKL. Calcification of hMSCs was evaluated via Alizarin Red S staining. Osteoclasts were identified using immunofluorescence staining observing multinucleated (DAPI) giant (ß-Actin) cells with TRAP and Cathepsin K activity. Additional gene expression analyses are currently conducted using qRT-PCR and looking for osteoclast-specific genes. In parallel to the monolayer cultures, cells were transferred on β-tricalcium phosphate (βTCP) – a suitable bony-like scaffold. Furthermore, first experiments in a dynamic bioreactor platform (OSPIN GmH) were conducted to evaluate the influence of shear stress on the cells and model systems.Results:We have been able to populate the βTCP scaffold with monocytes, which were differentiated into osteoclasts (morphological changes) without any effect on cellular viability as measured by Live/Dead staining. The morphological changes of those osteoclasts such as formation of filopodia could be demonstrated by scanning electron microscopy. In addition, the cultivation of βTCP populated with hMSCs in a perfusion system showed the upregulation of osteogenic markers (RUNX2, OSX) on mRNA-level.Conclusion:These first results of our approach to develop anin vitro3D model for glucocorticoid-induced osteoporosis are promising. Our next step will be the co-cultivation of osteoblasts and osteoclasts under dynamic and optimized cultivation conditions. By combining several cell types, a suitable scaffold and biomechanical stimuli (perfusion), we aim to provide a valid testing platform to study underlying disease mechanisms and for drug development.Acknowledgments:The project has been funded by the Elsbeth Bonhoff Foundation.Disclosure of Interests:Annemarie Lang: None declared, Karoline Diesing: None declared, Alexandra Damerau: None declared, Sümeyye Uzun: None declared, Moritz Pfeiffenberger: None declared, Timo Gaber: None declared, Frank Buttgereit Grant/research support from: Amgen, BMS, Celgene, Generic Assays, GSK, Hexal, Horizon, Lilly, medac, Mundipharma, Novartis, Pfizer, Roche, and Sanofi.

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EFFECT OF METAL NANOPARTICLES ON THE GROWTH OF NGOC LINH GINSENG (PANAX VIETNAMENSIS) LATERAL ROOTS CULTURED IN VITRO

HUE UNIVERSITY JOURNAL OF SCIENCE NATURAL SCIENCE ◽

10.26459/hueuni-jns.v126i1d.4524 ◽

2017 ◽

Vol 126 (1C) ◽

Author(s):

Duong Tan Nhut ◽

Nguyen Thi Nhat Linh ◽

Nguyen Hoang Loc ◽

Hoang Thanh Tung ◽

Vu Thi Hien ◽

...

Keyword(s):

Root Growth ◽

Metal Nanoparticles ◽

Lateral Root ◽

Root Formation ◽

Lateral Roots ◽

Metal Nanoparticle ◽

Ginseng Root ◽

Lateral Root Formation ◽

Triterpenoid Saponins

Panax vietnamensis (Ngoc Linh ginseng) plays critical roles in pharmaceutical industry because triterpenoid saponins from its roots produce medicine for improving health and treating many diseases. Metal nanoparticles reveal completely new or improved properties based on specific characteristics such as size, distribution and morphology compare to metal ion or salt; and their potential for in vitro plant cultures. Present study investigated the effects of metal nanoparticles including nZnO (0.5-2.5 mg/l), nAg (1-3 mg/l), and nCu (1-3 mg/l) supplemented in free-hormone-MS medium to in vitro Panax vietnamensis lateral root growth. Our results showed that metal nanoparticles have the positive effect on the growth of in vitro P. vietnamensis lateral roots with nAg, nCu, and nZnO. At different concentrations, in vitro P. vietnamensis lateral root growth also has various effects on the growth of lateral roots. In supplemented metal nanoparticle treatments, nCu is the most optimum for in vitro P. vietnamensis lateral root growth; the highest increase was obtained at 1.5 mg/l nCu treatment (99.3% lateral root formation and all root growth indexes are the highest). Besides, 2.5 mg/l nAg is also significantly noticed in ginseng root growth. However, the negative impact on the growth of the in vitro P. vietnamensis lateral roots showed when culture medium contained the highest concentration; such as the root growing inhibition of nCu and nAg above 2.5 mg/l. Especially, this decrease was higher with the application of nZnO0.5-2.5 mg/l (decrease the lateral root number) and 2.5 mg/l (decrease percent of lateral root formation).

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Nitrate and glutamate sensing by plant roots

Biochemical Society Transactions ◽

10.1042/bst0330283 ◽

2005 ◽

Vol 33 (1) ◽

pp. 283-286 ◽

Cited By ~ 36

Author(s):

S. Filleur ◽

P. Walch-Liu ◽

Y. Gan ◽

B.G. Forde

Keyword(s):

Root Growth ◽

Lateral Root ◽

Lateral Roots ◽

Primary Root ◽

Root Tip ◽

Root Tips ◽

Environmental Signals ◽

Specific Effects ◽

Large Numbers ◽

Low Concentrations

The architecture of a root system plays a major role in determining how efficiently a plant can capture water and nutrients from the soil. Growth occurs at the root tips and the process of exploring the soil volume depends on the behaviour of large numbers of individual root tips at different orders of branching. Each root tip is equipped with a battery of sensory mechanisms that enable it to respond to a range of environmental signals, including nutrients, water potential, light, gravity and touch. We have previously identified a MADS (MCM1, agamous, deficiens and SRF) box gene (ANR1) in Arabidopsis thaliana that is involved in modulating the rate of lateral root growth in response to changes in the external NO3− supply. Transgenic plants have been generated in which a constitutively expressed ANR1 protein can be post-translationally activated by treatment with dexamethasone (DEX). When roots of these lines are treated with DEX, lateral root growth is markedly stimulated but there is no effect on primary root growth, suggesting that one or more components of the regulatory pathway that operate in conjunction with ANR1 in lateral roots may be absent in the primary root tip. We have recently observed some very specific effects of low concentrations of glutamate on root growth, resulting in significant changes in root architecture. Experimental evidence suggests that this response involves the sensing of extracellular glutamate by root tip cells. We are currently investigating the possible role of plant ionotropic glutamate receptors in this sensory mechanism.

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Cellular and molecular events in a newly organizing lateral root meristem

Philosophical Transactions of the Royal Society B Biological Sciences ◽

10.1098/rstb.1995.0135 ◽

1995 ◽

Vol 350 (1331) ◽

pp. 39-43 ◽

Cited By ~ 17

Keyword(s):

Lateral Root ◽

Root Formation ◽

Developmental Process ◽

Lateral Roots ◽

Root Apical Meristem ◽

Cdna Libraries ◽

Lateral Root Formation ◽

Ribosomal Protein Genes ◽

Efficient System

Spontaneous or auxin-induced lateral root formation in radish and Arabidopsis provides an efficient system in which to examine molecular and cellular events associated with the initiation of a new meristem. Subtracted cDNA libraries made at different times in lateral root initiation were used as a source of genes that are expressed differentially during this developmental process, and expression studies on a small gene family of ribosomal protein genes were conducted. From analysis of cell division patterns in pericycle cells the number of founder cells for lateral roots was established. By the use of in vitro growth assays lateral root formation was determined to be a two-stage process. First a primordium is formed, and subsequently a subset of primordial cells begins to function as the lateral root apical meristem. This mode of root development has implications for pattern formation in newly organizing organs.

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Endothelial-to-haematopoietic transition: an update on the process of making blood

Biochemical Society Transactions ◽

10.1042/bst20180320 ◽

2019 ◽

Vol 47 (2) ◽

pp. 591-601 ◽

Cited By ~ 13

Author(s):

Katrin Ottersbach

Keyword(s):

Stem Cells ◽

Endothelial Cells ◽

Morphological Changes ◽

Imaging Techniques ◽

Transcriptional Profiling ◽

Clinical Importance ◽

Model Systems ◽

Detailed Knowledge ◽

Whole Process

Abstract The first definitive blood cells during embryogenesis are derived from endothelial cells in a highly conserved process known as endothelial-to-haematopoietic transition (EHT). This conversion involves activation of a haematopoietic transcriptional programme in a subset of endothelial cells in the major vasculature of the embryo, followed by major morphological changes that result in transitioning cells rounding up, breaking the tight junctions to neighbouring endothelial cells and adopting a haematopoietic fate. The whole process is co-ordinated by a complex interplay of key transcription factors and signalling pathways, with additional input from surrounding tissues. Diverse model systems, including mouse, chick and zebrafish embryos as well as differentiation of pluripotent cells in vitro, have contributed to the elucidation of the details of the EHT, which was greatly accelerated in recent years by sophisticated live imaging techniques and advances in transcriptional profiling, such as single-cell RNA-Seq. A detailed knowledge of these developmental events is required in order to be able to apply it to the generation of haematopoietic stem cells from pluripotent stem cells in vitro — an achievement which is of obvious clinical importance. The aim of this review is to summarise the latest findings and describe how these may have contributed towards achieving this goal.

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