scholarly journals How Plants Handle Trivalent (+3) Elements

2019 ◽  
Vol 20 (16) ◽  
pp. 3984 ◽  
Author(s):  
Charlotte Poschenrieder ◽  
Silvia Busoms ◽  
Juan Barceló
Keyword(s):  
Divalent Cations ◽  
Mineral Elements ◽  
Redox Activity ◽  
Biologically Relevant ◽  
Cell Compartments ◽  
Trivalent State ◽  
Global Vision ◽  
Trivalent Cations ◽  
Trivalent Element

Plant development and fitness largely depend on the adequate availability of mineral elements in the soil. Most essential nutrients are available and can be membrane transported either as mono or divalent cations or as mono- or divalent anions. Trivalent cations are highly toxic to membranes, and plants have evolved different mechanisms to handle +3 elements in a safe way. The essential functional role of a few metal ions, with the possibility to gain a trivalent state, mainly resides in the ion’s redox activity; examples are iron (Fe) and manganese. Among the required nutrients, the only element with +3 as a unique oxidation state is the non-metal, boron. However, plants also can take up non-essential trivalent elements that occur in biologically relevant concentrations in soils. Examples are, among others, aluminum (Al), chromium (Cr), arsenic (As), and antimony (Sb). Plants have evolved different mechanisms to take up and tolerate these potentially toxic elements. This review considers recent studies describing the transporters, and specific and unspecific channels in different cell compartments and tissues, thereby providing a global vision of trivalent element homeostasis in plants.

scholarly journals Lack of Interaction of Fluoroquinolones with Lipopolysaccharides

2002 ◽  
Vol 46 (5) ◽  
pp. 1568-1570 ◽  
Author(s):  
B. Lindner ◽  
A. Wiese ◽  
K. Brandenburg ◽  
U. Seydel ◽  
A. Dalhoff
Keyword(s):  
Outer Membrane ◽  
Antibacterial Effect ◽  
Divalent Cations ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Biologically Relevant ◽  
Mutant Strains ◽  
Trivalent Cations ◽  
Biophysical Techniques ◽  
Rough Mutant

ABSTRACT Fluoroquinolones are known to chelate with di- and trivalent cations, and it has accordingly been claimed that they perturb the integrity of the outer membrane (OM) of gram-negative bacteria. So far, chelation has not been assessed in biologically relevant test systems. Therefore, we investigated the interaction of ciprofloxacin and moxifloxacin in the absence and presence of Mg2+ with whole bacteria and isolated lipopolysaccharide (LPS) from various rough mutant strains of Salmonella enterica chemotypes by applying different biophysical techniques. We found that the fluoroquinolones did not disturb the integrity of the OM and neither were incorporated into LPS monolayers nor displaced Ca2+ from LPS monolayers, suggesting that chelation of fluoroquinolones with divalent cations does not contribute to the antibacterial effect of fluoroquinolones.

Ionic homeostasis and subcellular element compartmentation

1990 ◽  
Vol 48 (2) ◽  
pp. 150-151
Author(s):  
Ann LeFurgey ◽  
Peter Ingram ◽  
J.J. Blum ◽  
M.C. Carney ◽  
L.A. Hawkey ◽  
...  
Keyword(s):  
Leishmania Major ◽  
Ionic Homeostasis ◽  
X Ray ◽  
Functional Studies ◽  
Cell Compartments ◽  
X Ray Imaging ◽  
Resolution Electron ◽  
Multiple Cell ◽  
Role Of Zn

Subcellular compartments commonly identified and analyzed by high resolution electron probe x-ray microanalysis (EPXMA) include mitochondria, cytoplasm and endoplasmic or sarcoplasmic reticulum. These organelles and cell regions are of primary importance in regulation of cell ionic homeostasis. Correlative structural-functional studies, based on the static probe method of EPXMA combined with biochemical and electrophysiological techniques, have focused on the role of these organelles, for example, in maintaining cell calcium homeostasis or in control of excitation-contraction coupling. New methods of real time quantitative x-ray imaging permit simultaneous examination of multiple cell compartments, especially those areas for which both membrane transport properties and element content are less well defined, e.g. nuclei including euchromatin and heterochromatin, lysosomes, mucous granules, storage vacuoles, microvilli. Investigations currently in progress have examined the role of Zn-containing polyphosphate vacuoles in the metabolism of Leishmania major, the distribution of Na, K, S and other elements during anoxia in kidney cell nuclel and lysosomes; the content and distribution of S and Ca in mucous granules of cystic fibrosis (CF) nasal epithelia; the uptake of cationic probes by mltochondria in cultured heart ceils; and the junctional sarcoplasmic retlculum (JSR) in frog skeletal muscle.

scholarly journals Stoichiometric Analysis of Shifting in Subcellular Compartmentalization of HSP70 within Ischemic Penumbra

Molecules ◽  
2021 ◽  
Vol 26 (12) ◽  
pp. 3578
Author(s):  
Federica Mastroiacovo ◽  
Francesca Biagioni ◽  
Paola Lenzi ◽  
Larisa Ryskalin ◽  
Stefano Puglisi-Allegra ◽  
...  
Keyword(s):  
Direct Evidence ◽  
Neuronal Survival ◽  
Hsp 70 ◽  
Preclinical Models ◽  
Brain Areas ◽  
Cell Compartments ◽  
Control Brain ◽  
Disease Modifier ◽  
Subcellular Compartmentalization

The heat shock protein (HSP) 70 is considered the main hallmark in preclinical studies to stain the peri-infarct region defined area penumbra in preclinical models of brain ischemia. This protein is also considered as a potential disease modifier, which may improve the outcome of ischemic damage. In fact, the molecule HSP70 acts as a chaperonine being able to impact at several level the homeostasis of neurons. Despite being used routinely to stain area penumbra in light microscopy, the subcellular placement of this protein within area penumbra neurons, to our knowledge, remains undefined. This is key mostly when considering studies aimed at deciphering the functional role of this protein as a determinant of neuronal survival. The general subcellular placement of HSP70 was grossly reported in studies using confocal microscopy, although no direct visualization of this molecule at electron microscopy was carried out. The present study aims to provide a direct evidence of HSP70 within various subcellular compartments. In detail, by using ultrastructural morphometry to quantify HSP70 stoichiometrically detected by immuno-gold within specific organelles we could compare the compartmentalization of the molecule within area penumbra compared with control brain areas. The study indicates that two cell compartments in control conditions own a high density of HSP70, cytosolic vacuoles and mitochondria. In these organelles, HSP70 is present in amount exceeding several-fold the presence in the cytosol. Remarkably, within area penumbra a loss of such a specific polarization is documented. This leads to the depletion of HSP70 from mitochondria and mostly cell vacuoles. Such an effect is expected to lead to significant variations in the ability of HSP70 to exert its physiological roles. The present findings, beyond defining the neuronal compartmentalization of HSP70 within area penumbra may lead to a better comprehension of its beneficial/detrimental role in promoting neuronal survival.

scholarly journals Recapitulation of the Function and Role of ROS Generated in Response to Heat Stress in Plants

Plants ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 371
Author(s):  
Emily Medina ◽  
Su-Hwa Kim ◽  
Miriam Yun ◽  
Won-Gyu Choi
Keyword(s):  
Heat Stress ◽  
Plant Growth ◽  
Intracellular Signaling ◽  
Oxygen Species ◽  
Natural Ecosystems ◽  
Signaling Molecule ◽  
Signaling Systems ◽  
Cell Compartments ◽  
Tropical Area

In natural ecosystems, plants are constantly exposed to changes in their surroundings as they grow, caused by a lifestyle that requires them to live where their seeds fall. Thus, plants strive to adapt and respond to changes in their exposed environment that change every moment. Heat stress that naturally occurs when plants grow in the summer or a tropical area adversely affects plants’ growth and poses a risk to plant development. When plants are subjected to heat stress, they recognize heat stress and respond using highly complex intracellular signaling systems such as reactive oxygen species (ROS). ROS was previously considered a byproduct that impairs plant growth. However, in recent studies, ROS gained attention for its function as a signaling molecule when plants respond to environmental stresses such as heat stress. In particular, ROS, produced in response to heat stress in various plant cell compartments such as mitochondria and chloroplasts, plays a crucial role as a signaling molecule that promotes plant growth and triggers subsequent downstream reactions. Therefore, this review aims to address the latest research trends and understandings, focusing on the function and role of ROS in responding and adapting plants to heat stress.

scholarly journals Role of Selenium and Selenoproteins in Male Reproductive Function: A Review of Past and Present Evidences

Antioxidants ◽  
2019 ◽  
Vol 8 (8) ◽  
pp. 268 ◽  
Author(s):  
Izhar Hyder Qazi ◽  
Christiana Angel ◽  
Haoxuan Yang ◽  
Evangelos Zoidis ◽  
Bo Pan ◽  
...  
Keyword(s):  
Male Fertility ◽  
Defense Mechanisms ◽  
Antioxidant Defense ◽  
Biological Effects ◽  
Reproductive Function ◽  
Vital Role ◽  
Biologically Relevant ◽  
Male Reproductive Function ◽  
The Subject

Selenium (Se) is an important trace mineral having many essential roles at the cellular and organismal levels in animal and human health. The biological effects of Se are mainly carried out by selenoproteins (encoded by 25 genes in humans and 24 in mice). As an essential component of selenoproteins, Se performs structural and enzymic roles; in the latter context it is well known for its catalytic and antioxidative functions. Studies involving different animal models have added great value to our understanding regarding the potential implications of Se and selenoproteins in mammalian fertility and reproduction. In this review, we highlight the implications of selenoproteins in male fertility and reproduction followed by the characteristic biological functions of Se and selenoproteins associated with overall male reproductive function. It is evident from observations of past studies (both animal and human) that Se is essentially required for spermatogenesis and male fertility, presumably because of its vital role in modulation of antioxidant defense mechanisms and other essential biological pathways and redox sensitive transcription factors. However, bearing in mind the evidences from mainstream literature, it is also advisable to perform more studies focusing on the elucidation of additional roles played by the peculiar and canonical selenoproteins i.e., glutathione peroxidase 4 (GPX4) and selenoprotein P (SELENOP) in the male reproductive functions. Nevertheless, search for the elucidation of additional putative mechanisms potentially modulated by other biologically relevant selenoproteins should also be included in the scope of future studies. However, as for the implication of Se in fertility and reproduction in men, though a few clinical trials explore the effects of Se supplementation on male fertility, due to inconsistencies in the recruitment of subjects and heterogeneity of designs, the comparison of such studies is still complicated and less clear. Therefore, further research focused on the roles of Se and selenoproteins is awaited for validating the evidences at hand and outlining any therapeutic schemes intended for improving male fertility. As such, new dimensions could be added to the subject of male fertility and Se supplementation.

Crystallochemical classifications of phyllosilicates based on the unified system of projection of chemical composition: I. The mica group

Clay Minerals ◽  
1990 ◽  
Vol 25 (1) ◽  
pp. 73-81 ◽  
Author(s):  
A. Wiewióra
Keyword(s):  
Chemical Composition ◽  
Divalent Cations ◽  
Layer Charge ◽  
Vector Representation ◽  
Similar Formula ◽  
Crystallochemical Formula ◽  
Trivalent Cations ◽  
Image Position ◽  
Composition I ◽  
Unit Vectors

AbstractA unified system of vector representation of chemical composition is proposed for the phyllosilicates based on projection of the composition, as given by crystallochemical formula, onto a field with orthogonal axes chosen for octahedral divalent cations, R2+, and Si (X, Y, respectively), and oblique axes for octahedral trivalent cations, R3+, and vacancies, □, (V, Z, respectively). Point coordinates for each set of axes were used to define the direction and length of the unit vectors for phyllosilicates belonging to different groups. Parallel to these fundamental directions the composition isolines were drawn in the projection fields. Applied to micas, this system enables control of the chemical composition by the general crystallochemical formula covering all varieties of Li-free dioctahedral and trioctahedral micas:where z (number of vacancies) = (y-x+ m)/2; m (layer charge) =1; u+y+z = 3. There is a similar formula for vacancy-free lithian micas:where w = m — x+y;m=1; u+y+w = 3, and for Li-free brittle micas:where z = (y — x+m)/2; m = 2; u+y+z = 3. Projection fields were used to classify micas.

scholarly journals l-Aspartate: An Essential Metabolite for Plant Growth and Stress Acclimation

Molecules ◽  
2021 ◽  
Vol 26 (7) ◽  
pp. 1887
Author(s):  
Mei Han ◽  
Can Zhang ◽  
Peter Suglo ◽  
Shuyue Sun ◽  
Mingyao Wang ◽  
...  
Keyword(s):  
Plant Growth ◽  
Physiological Role ◽  
Tca Cycle ◽  
Extensive Study ◽  
Cell Compartments ◽  
Stress Acclimation ◽  
Whole Plant ◽  
Glycolysis Pathway ◽  
Acid Pathway

L-aspartate (Asp) serves as a central building block, in addition to being a constituent of proteins, for many metabolic processes in most organisms, such as biosynthesis of other amino acids, nucleotides, nicotinamide adenine dinucleotide (NAD), the tricarboxylic acid (TCA) cycle and glycolysis pathway intermediates, and hormones, which are vital for growth and defense. In animals and humans, lines of data have proved that Asp is indispensable for cell proliferation. However, in plants, despite the extensive study of the Asp family amino acid pathway, little attention has been paid to the function of Asp through the other numerous pathways. This review aims to elucidate the most important aspects of Asp in plants, from biosynthesis to catabolism and the role of Asp and its metabolic derivatives in response to changing environmental conditions. It considers the distribution of Asp in various cell compartments and the change of Asp level, and its significance in the whole plant under various stresses. Moreover, it provides evidence of the interconnection between Asp and phytohormones, which have prominent functions in plant growth, development, and defense. The updated information will help improve our understanding of the physiological role of Asp and Asp-borne metabolic fluxes, supporting the modular operation of these networks.

Fine structure of the heterochromatin of the kangaroo rat Dipidomys ordii, and examination of the possible role of actin and myosin in heterochromatin condensation

1976 ◽  
Vol 21 (3) ◽  
pp. 465-477
Author(s):  
D.E. Comings ◽  
T.A. Okada
Keyword(s):  
Constitutive Heterochromatin ◽  
Divalent Cations ◽  
Random Coils ◽  
Type Complex ◽  
Kangaroo Rat ◽  
Thin Section Electron Microscopy ◽  
Section Electron ◽  
Liver Nuclei ◽  
The Brain

Biochemical studies have suggested that some actin and myosin may be present in the nucleus. This raises the possibility that heterochromatin condensation might be the result of an actin-myosin rigour type complex. Since ATP dissociates actin and myosin, this possibility could be examined by determining the effect of ATP on heterochromatin condensation. Thin-section electron microscopy showed large amounts of condensed constitutive heterochromatin in the kidney nuclei and somewhat less in the liver nuclei of the kangaroo rat, Dipidomys ordii. Surprisingly, there were some nuclei in the brain which contained no condensed heterochromatin despite the fact that this genome is composed of 50% satellite DNA. Although washing kidney nuclei with solutions of 10 mM Tris-ATP caused marked decondensation of the heterochromatin, when they were washed with Mg-ATP the heterochromatin was more condensed than in the controls. This suggests the decondensation by Tris-ATP is due to its ability to chelate divalent cations and provides no support for condensation of heterochromatin being the result of myosin-actin interaction. Despite being decondensed, the chromatin fibres of heterochromatin were distinct from those of euchromatin. The heterochromatin formed rod-like 19-5 nm fibres, the euchromatin formed random coils of 11-0-nm fibres.

scholarly journals Role of divalent cations, pH, cytoskeleton componentes and surface charge on the adhesion of Trichomonas vaginalis to a polystyrene substrate

1987 ◽  
Vol 82 (3) ◽  
pp. 379-384 ◽  
Author(s):  
Fernando Costa e Silva Filho ◽  
Cezar Antonio Elias ◽  
Wanderley de Souza
Keyword(s):  
Surface Charge ◽  
Incubation Time ◽  
Trichomonas Vaginalis ◽  
Cytochalasin B ◽  
Culture Media ◽  
Divalent Cations ◽  
Polystyrene Beads ◽  
Different Strains ◽  
Adhesion Index

The process of adhesion of three different strains of Trichomonas vaginalis to a polystyrene substrate was analysed. The process of adhesion was dependent on the time of incubation and the pH of the phosphate-buffered solution (PBS) in which the parasites were suspended. The highest indices of adhesion were observed after an incubation time of 60 min at pH 6.6. The adhesion index increased when the parasites were incubated in the presence of culture media or when Ca++ or Mg++ was added to the PBS solution, whereas cytochalasin B, trypsin or neuraminidase reduced adhesion. Incubation of the parasites in the presence of poly-L-lysine facilitated the process of adhesion. Incubation of the parasites or polystyrene beads in the presence of poly-L-lysine led to important changes in their surface charge.

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