scholarly journals Rhizophagy Cycle: An Oxidative Process in Plants for Nutrient Extraction from Symbiotic Microbes

2018 ◽  
Vol 6 (3) ◽  
pp. 95 ◽  
Author(s):  
James White ◽  
Kathryn Kingsley ◽  
Satish Verma ◽  
Kurt Kowalski
Keyword(s):  
Cell Walls ◽  
Plasma Membranes ◽  
Reactive Oxygen ◽  
Root Tip ◽  
Free Living ◽  
Root Cells ◽  
Cell Plasma ◽  
Cell Shapes ◽  
Bacteria And Fungi ◽  
Nutrient Extraction

In this paper, we describe a mechanism for the transfer of nutrients from symbiotic microbes (bacteria and fungi) to host plant roots that we term the ‘rhizophagy cycle.’ In the rhizophagy cycle, microbes alternate between a root intracellular endophytic phase and a free-living soil phase. Microbes acquire soil nutrients in the free-living soil phase; nutrients are extracted through exposure to host-produced reactive oxygen in the intracellular endophytic phase. We conducted experiments on several seed-vectored microbes in several host species. We found that initially the symbiotic microbes grow on the rhizoplane in the exudate zone adjacent the root meristem. Microbes enter root tip meristem cells—locating within the periplasmic spaces between cell wall and plasma membrane. In the periplasmic spaces of root cells, microbes convert to wall-less protoplast forms. As root cells mature, microbes continue to be subjected to reactive oxygen (superoxide) produced by NADPH oxidases (NOX) on the root cell plasma membranes. Reactive oxygen degrades some of the intracellular microbes, also likely inducing electrolyte leakage from microbes—effectively extracting nutrients from microbes. Surviving bacteria in root epidermal cells trigger root hair elongation and as hairs elongate bacteria exit at the hair tips, reforming cell walls and cell shapes as microbes emerge into the rhizosphere where they may obtain additional nutrients. Precisely what nutrients are transferred through rhizophagy or how important this process is for nutrient acquisition is still unknown.

Changes in lipid composition of oat root membranes as a function of water-deficit stress

1985 ◽  
Vol 63 (2) ◽  
pp. 77-84 ◽  
Author(s):  
C. Liljenberg ◽  
M. Kates
Keyword(s):  
Fatty Acids ◽  
Plasma Membrane ◽  
Water Deficit ◽  
Lipid Composition ◽  
Membrane Fraction ◽  
Plasma Membranes ◽  
Root Tip ◽  
Water Deficit Stress ◽  
Root Cells ◽  
Steryl Esters

The effect of repeated water-deficit stress on the lipid composition of root cells from 5-day-old oat (Avena sativa L. cv. Seger) seedlings was studied. The content of total acyl lipids was found to decrease with increasing degree of water-deficit stress, owing largely to decreases in free fatty acids, triglycerides, phosphatidylethanolamine (PE), wax esters, steryl esters, and acylated steryl glycosides. Major polar lipids both in total root cells and in the plasma membrane enriched fraction, as well as the microsomal membrane fraction, were PE, phosphatidylcholine (PC), digalactosyldiacylglycerol (DGDG), monogalactosyldiacylglycerol (MGDG), and polyglycolipid. Decreases in the degree of unsaturation of the fatty acids as a funtion of increased water-deficit stress were observed for the MGDG and polyglycolipid components of total root cells and for the MGDG, DGDG, and polyglycolipid of the plasma membrane fraction. Electron microscopy showed that stressed root tip cells had much smoother plasma membranes than those of control unstressed root cells. These results suggest that root cells of oat seedlings respond to water-deficit stress by reducing the total plasma membrane mass and degree of lipid fluidity, which would reduce the water permeability of the plasma membranes and help maintain cell turgidity.

scholarly journals Facilitated transport of Mn2+ in sycamore (Acer pseudoplatanus) cells and excised maize root tips. A comparative 31P n.m.r. study in vivo

1988 ◽  
Vol 252 (2) ◽  
pp. 401-408 ◽  
Author(s):  
C Roby ◽  
R Bligny ◽  
R Douce ◽  
S I Tu ◽  
P E Pfeffer
Keyword(s):  
Metal Ion ◽  
Plasma Membranes ◽  
Maize Root ◽  
Root Tip ◽  
Acer Pseudoplatanus ◽  
Relative Distribution ◽  
Root Tips ◽  
Root Cells ◽  
Hypoxic Conditions

Movement of paramagnetic Mn2+ into sycamore (Acer pseudoplatanus) cells has been indirectly examined by observing the line broadening exhibited in its 31P n.m.r. spectra. Mn2+ was observed to pass into the vacuole, while exhibiting a very minor accumulation in the cytoplasm. With time, gradual leakage of phosphate from the vacuole to the cytoplasm was observed along with an increase in glucose-6-phosphate. Anoxia did not appear to affect the relative distribution of Mn2+ in the cytoplasm and vacuole. Under hypoxic conditions restriction of almost all movement of Mn2+ across the plasmalemma as well as the tonoplast was observed. In contrast, maize root tips showed entry and complete complexation of nucleotide triphosphate by Mn2+ during hypoxia. The rate of passage of Mn2+ across the tonoplast in both sycamore and maize root cells is approximately the same. However, the rates of facilitated movement across the respective plasma membranes appear to differ. More rapid movement of Mn2+ across the plasmalemma in maize root tip cells allows a gradual build-up of metal ion in the cytoplasm prior to its diffusion across the tonoplast. Sycamore cells undergo a slower uptake of Mn2+ into their cytoplasms (comparable with the rate of diffusion through the tonoplast), so little or no observable accumulation of Mn2+ is observed in this compartment.

scholarly journals FlsnRNA-seq: protoplasting-free full-length single-nucleus RNA profiling in plants

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Yanping Long ◽  
Zhijian Liu ◽  
Jinbu Jia ◽  
Weipeng Mo ◽  
Liang Fang ◽  
...  
Keyword(s):  
Single Cell ◽  
Cell Walls ◽  
Large Scale ◽  
Full Length ◽  
Cell Level ◽  
Root Cells ◽  
Rna Profiling ◽  
Different Types ◽  
Long Read ◽  
Single Nucleus

AbstractThe broad application of single-cell RNA profiling in plants has been hindered by the prerequisite of protoplasting that requires digesting the cell walls from different types of plant tissues. Here, we present a protoplasting-free approach, flsnRNA-seq, for large-scale full-length RNA profiling at a single-nucleus level in plants using isolated nuclei. Combined with 10x Genomics and Nanopore long-read sequencing, we validate the robustness of this approach in Arabidopsis root cells and the developing endosperm. Sequencing results demonstrate that it allows for uncovering alternative splicing and polyadenylation-related RNA isoform information at the single-cell level, which facilitates characterizing cell identities.

scholarly journals Insulin-induced rapid decrease of a major protein in fat cell plasma membranes.

1984 ◽  
Vol 259 (19) ◽  
pp. 12112-12116
Author(s):  
E J Schoenle ◽  
L D Adams ◽  
D W Sammons
Keyword(s):  
Plasma Membranes ◽  
Rapid Decrease ◽  
Major Protein ◽  
Fat Cell ◽  
Cell Plasma

scholarly journals Charged anaesthetics alter LM-fibroblast plasma-membrane enzymes by selective fluidization of inner or outer membrane leaflets

1986 ◽  
Vol 239 (2) ◽  
pp. 301-310 ◽  
Author(s):  
W D Sweet ◽  
F Schroeder
Keyword(s):  
Plasma Membrane ◽  
Active Site ◽  
Plasma Membranes ◽  
Local Anaesthetics ◽  
Cationic Drugs ◽  
Cell Plasma ◽  
Composition And Structure ◽  
Highly Sensitive ◽  
Functional Consequences ◽  
Anionic Drugs

The functional consequences of the differences in lipid composition and structure between the two leaflets of the plasma membrane were investigated. Fluorescence of 1,6-diphenylhexa-1,3,5-triene(DPH), quenching, and differential polarized phase fluorimetry demonstrated selective fluidization by local anaesthetics of individual leaflets in isolated LM-cell plasma membranes. As measured by decreased limiting anisotropy of DPH fluorescence, cationic (prilocaine) and anionic (phenobarbital and pentobarbital) amphipaths preferentially fluidized the cytofacial and exofacial leaflets respectively. Unlike prilocaine, procaine, also a cation, fluidized both leaflets of these membranes equally. Pentobarbital stimulated 5′-nucleotidase between 0.1 and 5 mM and inhibited at higher concentrations, whereas phenobarbital only inhibited, at higher concentrations. Cationic drugs were ineffective. Two maxima of (Na+ + K+)-ATPase activation were obtained with both anionic drugs. Only one activation maximum was obtained with both cationic drugs. The maximum in activity below 1 mM for all four drugs clustered about a single limiting anisotropy value in the cytofacial leaflet, whereas there was no correlation between activity and limiting anisotropy in the exofacial leaflets. Therefore, although phenobarbital and pentobarbital below 1 mM fluidized the exofacial leaflet more than the cytofacial leaflet, the smaller fluidization in the cytofacial leaflet was functionally significant for (Na+ + K+)-ATPase. Mg2+-ATPase was stimulated at 1 mM-phenobarbital, unaffected by pentobarbital and slightly stimulated by both cationic drugs at concentrations fluidizing both leaflets. Thus the activity of (Na+ + K+)-ATPase was highly sensitive to selective fluidization of the leaflet containing its active site, whereas the other enzymes examined were little affected by fluidization of either leaflet.

scholarly journals A rapid immunological procedure for the isolation of hormonally sensitive rat fat-cell plasma membrane

1976 ◽  
Vol 154 (1) ◽  
pp. 11-21 ◽  
Author(s):  
J P Luzio ◽  
A C Newby ◽  
C N Hales
Keyword(s):  
Plasma Membrane ◽  
Adenylate Cyclase ◽  
Plasma Membranes ◽  
Membrane Preparation ◽  
Fat Cells ◽  
Fat Cell ◽  
Cell Plasma ◽  
Rat Fat Cells ◽  
Plasma Membrane Preparation ◽  
Isolated Rat

1. A rapid method for the isolation of hormonally sensitive rat fat-cell plasma membranes was developed by using immunological techniques. 2. Rabbit anti-(rat erythrocyte) sera were raised and shown to cross-react with isolated rat fat-cells. 3. Isolated rat fat-cells were coated with rabbit anti-(rat erythrocyte) antibodies, homogenized and the homogenate made to react with an immunoadsorbent prepared by covalently coupling donkey anti-(rabbit globulin) antibodies to aminocellulose. Uptake of plasma membrane on to the immunoadsorbent was monitored by assaying the enzymes adenylate cyclase and 5′-nucleotidase and an immunological marker consisting of a 125I-labelled anti-(immunoglobulin G)-anti-cell antibody complex bound to the cells before fractionation. Contamination of the plasma-membrane preparation by other subcellular fractions was also investigated. 4. By using this technique, a method was developed allowing 25-40% recovery of plasma membrane from fat-cell homogenates within 30 min of homogenization. 5. Adenylate cyclase in the isolated plasma-membrane preparation was stimulated by 5 μm-adrenaline.

Distribution of anionic sites on surface of B cell granule and plasma membranes: a study using cationic ferritin

1977 ◽  
Vol 27 (1) ◽  
pp. 289-301
Author(s):  
S.L. Howell ◽  
M. Tyhurst
Keyword(s):  
B Cell ◽  
Plasma Membranes ◽  
Calcium Concentration ◽  
Anionic Sites ◽  
Neuraminidase Treatment ◽  
Visual Probe ◽  
Cell Plasma ◽  
Granule Membrane ◽  
Pancreatic B Cells ◽  
Storage Granules

The distribution of anionic sites on the membranes of rat pancreatic B cells and of their storage granules has been studied by the use of a visual probe of cationic ferritin. Membranes of isolated storage granules possessed a net negative charge which was apparently evenly distributed; the number of anionic sites was not markedly altered by prior incubation of the granules with neuraminidase or with 10(−5) to 2 X 10(−3) M calcium chloride. Distribution of charges along B cell plasma membranes was less uniform but was similarly unaffected by alterations of calcium concentration, or by neuraminidase treatment. However, during the fusion of plasma membrane and granule membrane which occurs in exocytosis, the emerging granule membrane was found to be devoid of anionic sites. The implications of these findings for the regulation of insulin secretion by exocytosis are discussed.

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