scholarly journals Phosphate deprivation induces transfer of DGDG galactolipid from chloroplast to mitochondria

2004 ◽  
Vol 167 (5) ◽  
pp. 863-874 ◽  
Author(s):  
Juliette Jouhet ◽  
Eric Maréchal ◽  
Barbara Baldan ◽  
Richard Bligny ◽  
Jacques Joyard ◽  
...  
Keyword(s):  
Plant Cells ◽  
Cellular Level ◽  
Endomembrane System ◽  
High Concentration ◽  
Cell Content ◽  
Phosphate Deprivation ◽  
Early Stages ◽  
Plastid Envelope ◽  
Plastid Membranes

In many soils plants have to grow in a shortage of phosphate, leading to development of phosphate-saving mechanisms. At the cellular level, these mechanisms include conversion of phospholipids into glycolipids, mainly digalactosyldiacylglycerol (DGDG). The lipid changes are not restricted to plastid membranes where DGDG is synthesized and resides under normal conditions. In plant cells deprived of phosphate, mitochondria contain a high concentration of DGDG, whereas mitochondria have no glycolipids in control cells. Mitochondria do not synthesize this pool of DGDG, which structure is shown to be characteristic of a DGD type enzyme present in plastid envelope. The transfer of DGDG between plastid and mitochondria is investigated and detected between mitochondria-closely associated envelope vesicles and mitochondria. This transfer does not apparently involve the endomembrane system and would rather be dependent upon contacts between plastids and mitochondria. Contacts sites are favored at early stages of phosphate deprivation when DGDG cell content is just starting to respond to phosphate deprivation.

Isolation of polypeptides with microtubule-translocating activity from phragmoplasts of tobacco BY-2 cells

1994 ◽  
Vol 107 (8) ◽  
pp. 2249-2257 ◽  
Author(s):  
T. Asada ◽  
H. Shibaoka
Keyword(s):  
Motor Activity ◽  
Molecular Basis ◽  
Plant Cells ◽  
Cell Plate ◽  
Gtpase Activity ◽  
High Concentration ◽  
Higher Plant ◽  
Main Components ◽  
Brain Tubulin

As part of our efforts to understand the molecular basis of the microtubule-associated motility that is involved in cytokinesis in higher plant cells, an attempt was made to identify proteins with the ability to translocate microtubules in an extract from isolated phragmoplasts. Homogenization of isolated phragmoplasts in a solution that contained MgATP, MgGTP and a high concentration of NaCl resulted in the release from phragmoplasts of factors with ATPase and GTPase activity that were stimulated by microtubules. A protein fraction with microtubule-dependent ATPase and GTPase activity caused minus-end-headed gliding of microtubules in the presence of ATP or GTP. Polypeptides with microtubule-translocating activity cosedimented with microtubules that had been assembled in vitro from brain tubulin and were dissociated from sedimented microtubules by addition of ATP or GTP. After cosedimentation and dissociation procedures, a 125 kDa polypeptide and a 120 kDa polypeptide were recovered in a fraction that supported minus-end-headed gliding of microtubules. The rate of microtubule gliding that was caused by the fraction that contained the 125 kDa and 120 kDa polypeptides as main components was 1.28 microns/minute in the presence of ATP and 0.50 microns/minute in the presence of GTP. This fraction contained some microtubule-associated polypeptides in addition to the 125 kDa and 120 kDa polypeptides, but a fraction that contained only these additional polypeptides did not cause any translocation of microtubules. Thus, it appeared that the 125 kDa and 120 kDa polypeptides were responsible for translocation of microtubules. These polypeptides with plus-end-directed motor activity may play an important role in formation of the cell plate and in the organization of the phragmoplast.

scholarly journals Quality control in oocytes by p63 is based on a spring-loaded activation mechanism on the molecular and cellular level

eLife ◽  
2016 ◽  
Vol 5 ◽  
Author(s):  
Daniel Coutandin ◽  
Christian Osterburg ◽  
Ratnesh Kumar Srivastav ◽  
Manuela Sumyk ◽  
Sebastian Kehrloesser ◽  
...  
Keyword(s):  
Dna Damage ◽  
Quality Control ◽  
Cellular Level ◽  
Activation Mechanism ◽  
Control Factor ◽  
Dna Double Strand Breaks ◽  
High Concentration ◽  
P53 Family ◽  
Strand Breaks ◽  
Induced Apoptosis

Mammalian oocytes are arrested in the dictyate stage of meiotic prophase I for long periods of time, during which the high concentration of the p53 family member TAp63α sensitizes them to DNA damage-induced apoptosis. TAp63α is kept in an inactive and exclusively dimeric state but undergoes rapid phosphorylation-induced tetramerization and concomitant activation upon detection of DNA damage. Here we show that the TAp63α dimer is a kinetically trapped state. Activation follows a spring-loaded mechanism not requiring further translation of other cellular factors in oocytes and is associated with unfolding of the inhibitory structure that blocks the tetramerization interface. Using a combination of biophysical methods as well as cell and ovary culture experiments we explain how TAp63α is kept inactive in the absence of DNA damage but causes rapid oocyte elimination in response to a few DNA double strand breaks thereby acting as the key quality control factor in maternal reproduction.

scholarly journals Libidibia ferrea (jucá), a Traditional Anti-Inflammatory: A Study of Acute Toxicity in Adult and Embryos Zebrafish (Danio rerio)

2019 ◽  
Vol 12 (4) ◽  
pp. 175 ◽  
Author(s):  
Diego Q. Ferreira ◽  
Thamara O. Ferraz ◽  
Raquel S. Araújo ◽  
Rodrigo Alves Souza Cruz ◽  
Caio Pinho Fernandes ◽  
...  
Keyword(s):  
Acute Toxicity ◽  
Medicinal Product ◽  
Plant Species ◽  
Danio Rerio ◽  
Folk Medicine ◽  
Cellular Level ◽  
High Concentration ◽  
Phytochemical Composition ◽  
Inflammatory Processes ◽  
Hydroethanolic Extract

The plant species Libidibia ferrea (Mart. ex Tul.) LP Queiroz var. ferrea basionym of Caesalpinia ferrea (Mart. ex Tul.) is used in various regions of Brazil in folk medicine in the treatment of several health problems, especially in acute and chronic inflammatory processes. Most of the preparations employed are alcoholic. Therefore, this study aimed to evaluate the acute toxicity of the hydroethanolic extract of fruits of Libidibia ferrea (EHEFLf) in zebrafish, emphasizing the possible changes in the organic-cellular level of the gills, liver, kidneys, and intestine and on embryos. The result obtained by LC-M/MS from EHEFLf indicated a high concentration of possible polyhydroxylated substances. EHEFLf, at a dose of 2 g/kg orally, produced non-significant alterations of the analyzed organs. However, for embryos, the treatment with different concentrations demonstrated heart toxicity that was concentration-dependent. There is no evidence of a correlation of the observed effects with the phytochemical composition, and considering the species of animal used, it can be suggested that the oral use of L. ferrea hydroethanolic extract has an acceptable degree of safety for use as an oral medicinal product. and embryo results have shown significant affinity to the heart; however, it is perceived to be related to the concentrations used.

scholarly journals Protective Roles of Cytosolic and Plastidal Proteasomes on Abiotic Stress and Pathogen Invasion

Plants ◽  
2020 ◽  
Vol 9 (7) ◽  
pp. 832
Author(s):  
Md. Sarafat Ali ◽  
Kwang-Hyun Baek
Keyword(s):  
Abiotic Stress ◽  
Cell Survival ◽  
Plant Cells ◽  
Cellular Level ◽  
26S Proteasome ◽  
Pathogen Invasion ◽  
Cellular Environment ◽  
Abiotic Stressors ◽  
Different Types ◽  
Clp Proteases

Protein malfunction is typically caused by abiotic stressors. To ensure cell survival during conditions of stress, it is important for plant cells to maintain proteins in their respective functional conformation. Self-compartmentalizing proteases, such as ATP-dependent Clp proteases and proteasomes are designed to act in the crowded cellular environment, and they are responsible for degradation of misfolded or damaged proteins within the cell. During different types of stress conditions, the levels of misfolded or orphaned proteins that are degraded by the 26S proteasome in the cytosol and nucleus and by the Clp proteases in the mitochondria and chloroplasts increase. This allows cells to uphold feedback regulations to cellular-level signals and adjust to altered environmental conditions. In this review, we summarize recent findings on plant proteolytic complexes with respect to their protective functions against abiotic and biotic stressors.

Anatomical and Topochemical Aspects of Japanese beech (Fagus crenata) Cell Walls After Treatment with the Ionic Liquid, 1-Ethylpyridinium Bromide

2015 ◽  
Vol 21 (6) ◽  
pp. 1562-1572 ◽  
Author(s):  
Toru Kanbayashi ◽  
Hisashi Miyafuji
Keyword(s):  
Ionic Liquid ◽  
Cell Walls ◽  
Middle Lamella ◽  
Morphological Characteristics ◽  
Fagus Crenata ◽  
Cellular Level ◽  
Chemical Components ◽  
Wood Fibers ◽  
High Concentration ◽  
Japanese Beech

AbstractChanges in the ultrastructure and chemical components, and their distribution in Japanese beech (Fagus crenata), during the ionic liquid 1-ethylpyridinium bromide ([EtPy][Br]) treatment were examined at the cellular level by light microscopy, scanning electron microscopy, and confocal Raman microscopy. Each of the tissues, including wood fibers, vessels and parenchyma cells treated with [EtPy][Br] showed specific morphological characteristics. Furthermore, lignin can be preferentially liquefied and eluted in [EtPy][Br] from the cell walls when compared to polysaccharides. However, the delignification was heterogeneous on the cell walls as lignin maintained a relatively high-concentration at the compound middle lamella, cell corners, inner surface of the secondary wall, and pits after [EtPy][Br] treatment.

scholarly journals The effect of nitrogen excess in the feeding of cucumber plants (Cucumis sativus L. ) growing in conditions of various medium humiditv

2013 ◽  
Vol 56 (1-2) ◽  
pp. 37-45
Author(s):  
Edward Borowski ◽  
Zbyszek K. Blamowski ◽  
Janusz Wierciński
Keyword(s):  
Activity Index ◽  
Physiological Activity ◽  
Plant Cells ◽  
Stress Effect ◽  
High Nitrogen ◽  
High Concentration ◽  
Fluorescence Parameters ◽  
N Dose ◽  
C Value ◽  
Nitrogen Excess

Reaction of 21 days old cucumber plants on high nitrogen supply during the growth in the conditions of 70% and 30% fwc sand humidity was studied in the phytotron. Obtained results showed that nitrogen in concentration 24 mmol·dm<sup>-3</sup> (9 mmol higher than in Hoagland's medium) increased WSD, g<sub>s</sub>, E, P<sub>n</sub>, as well as content of some monosaccharides (ribose, glucose, fructose), disaccharides (saccharose, trehalase), proline and trigoneline but fresh mass of plants, leaf area and c, value in cucumber plants decreased„ However the effect of higher N dose on chlorophyll content in leaves and its fluorescence parameters (F<sub>v</sub>/F<sub>m</sub>, F<sub>v</sub>'/F<sub>m</sub>', ΦPSII, Q<sub>p</sub> i Q<sub>n</sub>) have not been noticed. Moreover, it has been shown that influence of supraoptimal N dose on the value of determined plant physiological activity index was considerably bigger in 30% than 70% sand humidity. The authors suggest that high concentration of nitrogen in medium evokes changes in metabolity of carbohydrates and nitrogen substances which lead to an osmoprotectans increase in plant cells. In this way plants are more resistant to an environmental stress effect.

scholarly journals The nature of conditioning nutrients for human malignant melanoma cultures

1983 ◽  
Vol 62 (1) ◽  
pp. 249-266
Author(s):  
K.A. Ellem ◽  
G.F. Kay
Keyword(s):  
Molecular Weight ◽  
Cell Density ◽  
Cell Attachment ◽  
Cell Types ◽  
Fresh Medium ◽  
Low Molecular Weight ◽  
High Concentration ◽  
Cell Content ◽  
Human Malignant Melanoma ◽  
Serum Factors

From a human melanoma line (MM96), showing some dependence of its rate of growth and cell attachment on serum concentration, sublines were selected for even greater dependence on serum factors. These sublines were used to identify the production of substances by other melanoma cells in culture that would supplement or replace the requirement for serum. Most of the sublines showed higher colony-forming efficiency in medium conditioned by one of several cell types in the presence of a low concentration of serum (2.5%) compared with fresh medium containing a high concentration of serum (10%). The conditioning factor(s) were found to be moderately heat-stable, nonlipophilic, and to be of low molecular weight (less than or greater than 400). Screening of a variety of non-essential low molecular weight nutrients, which have been reported to potentiate the growth of a variety of cell types in low-density culture, was positive for the MM96 sublines only for pyruvate. In particular, L-alanine, L-serine, putrescine and alpha MSH (melanocyte-stimulating hormone) were ineffective. Despite the problems of comparing conditioned media with fresh medium, a reasonable correlation between the stimulatory effect and the cell content of added 2-oxocarboxylates was apparent. As would be anticipated, MM96 cultures showed a population density-dependent enhancement of growth up to a cell density of 2 to 4 × 10(4) cells cm-2. Further increase in the initial cell density of these cultures led to a decline in growth rate. An important additional observation was that simple dilution of the ingredients of RPMI1640 with phosphate-buffered saline or Hanks' balanced salt solution led to a reversal of growth inhibition accompanying a serum shift-down.

scholarly journals Phylogenetic and structural analysis of annexins in pea (Pisum sativum L.) and their role in legume-rhizobial symbiosis development

2021 ◽  
Vol 25 (5) ◽  
pp. 502-513
Author(s):  
O. A. Pavlova ◽  
I. V. Leppyanen ◽  
D. V. Kustova ◽  
A. D. Bovin ◽  
E. A. Dolgikh
Keyword(s):  
Fluorescent Protein ◽  
Calcium Influx ◽  
Protein Localization ◽  
Yellow Fluorescent Protein ◽  
Plant Cells ◽  
Pcr Analysis ◽  
35S Promoter ◽  
Early Stages ◽  
Proteomic Approach ◽  
Rhizobial Symbiosis

Annexins as Ca2+/phospholipid-binding proteins are involved in the control of many biological processes essential for plant growth and development. In a previous study, we had shown, using a proteomic approach, that the synthesis of two annexins is induced in pea roots in response to rhizobial inoculation. In this study, phylogenetic analysis identified these annexins as PsAnn4 and PsAnn8 based on their homology with annexins from other legumes. The modeling approach allowed us to estimate the structural features of these annexins that might influence their functional activity. To verify the functions of these annexins, we performed comparative proteomic analysis, experiments with calcium influx inhibitors, and localization of labeled proteins. Essential down-regulation of PsAnn4 synthesis in a non-nodulating pea mutant P56 (sym10) suggests an involvement of this annexin in the rhizobial symbiosis. Quantitative RT-PCR analysis showed that PsAnn4 was upregulated at the early stages of symbiosis development, starting from 1–3 days after inoculation to up to 5 days after inoculation, while experiments with the Ca2+ channel blocker LaCl3 revealed its negative influence on this expression. To follow the PsAnn4 protein localization in plant cells, it was fused to the fluorophores such as red fluorescent protein (RFP) and yellow fluorescent protein (YFP) and expressed under the transcriptional regulation of the 35S promoter in Nicotiana benthamiana leaves by infiltration with Agrobacterium tumefaciens. The localization of PsAnn4 in the cell wall or plasma membrane of plant cells may indicate its participation in membrane modification or ion transport. Our results suggest that PsAnn4 may play an important role during the early stages of pea-rhizobial symbiosis development.

Identification and preliminary characterization of a 65 kDa higher-plant microtubule-associated protein

1993 ◽  
Vol 105 (4) ◽  
pp. 891-901 ◽  
Author(s):  
J. Chang-Jie ◽  
S. Sonobe
Keyword(s):  
Polyclonal Antibodies ◽  
Cold Treatment ◽  
Plant Cells ◽  
Anion Exchange Chromatography ◽  
Exchange Chromatography ◽  
High Concentration ◽  
Animal Cells ◽  
Higher Plant ◽  
Microtubule Protein

Microtubules in plant cells, as in animal cells, are dynamic structures. However, our lack of knowledge about the constituents of microtubules in plant cells has prevented us from understanding the mechanisms that control microtubule dynamics. To characterize some of these constituents, a cytoplasmic extract was prepared from evacuolated protoplasts (miniprotoplasts) of tobacco BY-2 cells, and microtubules were assembled in the presence of taxol and disassembled by cold treatment in the presence of Ca2+ and a high concentration of NaCl. SDS-PAGE analysis of triple-cycled microtubule protein revealed the presence of 120 kDa, 110 kDa and a group of 60–65 kDa polypeptides in addition to tubulin. Since these polypeptides had copolymerized with tubulin, through the three cycles of assembly and disassembly, and they bundle microtubules, we tentatively identified the three polypeptides as microtubule-associated proteins (MAPs). To characterize these factors further, triple-cycled microtubule protein was fractionated by Mono-Q anion-exchange chromatography and the microtubule-bundling activity of each fraction was examined. Fractions having microtubule-bundling activity contained only the 65 kDa MAP, an indication that the 65 kDa MAP is responsible for the bundling of microtubules. Purified 65 kDa MAP formed cross-bridge structures between adjacent microtubules in vitro. Polyclonal antibodies were raised in mice against the 65 kDa MAP. Immunofluorescence microscopy revealed that the 65 kDa MAP colocalized with microtubules in BY-2 cells throughout the cell cycle. Western blotting analysis of extracts from several species of plants suggested that the 65 kDa MAP and/or related peptides are widely distributed in the plant kingdom.

Sign in / Sign up

Export Citation Format

Share Document