scholarly journals Cytosolic Ni(II) Sensor in Cyanobacterium

2012 ◽  
Vol 287 (15) ◽  
pp. 12142-12151 ◽  
Author(s):  
Andrew W. Foster ◽  
Carl J. Patterson ◽  
Rafael Pernil ◽  
Corinna R. Hess ◽  
Nigel J. Robinson
Keyword(s):  
Coordination Sphere ◽  
Promoter Region ◽  
Nitrilotriacetic Acid ◽  
The Other ◽  
Cryptic Promoter ◽  
Difference Spectra ◽  
Inner Membrane ◽  
Fura 2 ◽  
Metal Selectivity ◽  
Metal Sensors

Efflux of surplus Ni(II) across the outer and inner membranes of Synechocystis PCC 6803 is mediated by the Nrs system under the control of a sensor of periplasmic Ni(II), NrsS. Here, we show that the product of ORF sll0176, which encodes a CsoR/RcnR-like protein now designated InrS (for internal nickel-responsive sensor), represses nrsD (NrsD is deduced to efflux Ni(II) across the inner membrane) from a cryptic promoter between the final two ORFs in the nrs operon. Transcripts initiated from the newly identified nrsD promoter accumulate in response to nickel or cobalt but not copper, and recombinant InrS forms specific, Ni(II)-inhibited complexes with the nrsD promoter region. Metal-dependent difference spectra of Ni(II)- and Cu(I)-InrS are similar to Cu(I)-sensing CsoR and dissimilar to Ni(II)/Co(II)-sensing RcnR, consistent with factors beyond the primary coordination sphere switching metal selectivity. Competition with chelators mag-fura-2, nitrilotriacetic acid, EDTA, and EGTA estimate KD Ni(II) for the tightest site of InrS as 2.05 (±1.5) × 10−14m, and weaker KD Ni(II) for the cells' metal sensors of other types: Zn(II) co-repressor Zur, Co(II) activator CoaR, and Zn(II) derepressor ZiaR. Ni(II) transfer to InrS occurs upon addition to Ni(II) forms of each other sensor. InrS binds Ni(II) sufficiently tightly to derepress Ni(II) export at concentrations below KD Ni(II) of the other sensors.

On the Scales Associated with Near-Infrared Reflectance Difference Spectra

1995 ◽  
Vol 49 (6) ◽  
pp. 765-772 ◽  
Author(s):  
M. S. Dhanoa ◽  
S. J. Lister ◽  
R. J. Barnes
Keyword(s):  
Near Infrared ◽  
Scatter Correction ◽  
The Other ◽  
Difference Spectra ◽  
Near Infrared Reflectance ◽  
Standard Normal Variate ◽  
Near Infrared Spectra ◽  
Standard Normal ◽  
Relationship Of ◽  
The Relationship

Scale differences of individual near-infrared spectra are identified when set-independent standard normal variate (SNV) and de-trend (DT) transformations are applied in either SNV followed by DT or DT then SNV order. The relationship of set-dependent multiplicative scatter correction (MSC) to SNV is also referred to. A simple correction factor is proposed to convert derived spectra from one order to the other. It is suggested that the suitable order for the study of changes using difference spectra (when removing baselines) should be DT followed by SNV, which leads to all derived spectra on the scale of mean zero and variance equal to one. If baselines are identical, then SNV scale spectra can be used to calculate differences.

scholarly journals In the non-insect-transmissible line of onion yellows phytoplasma (OY-NIM), the plasmid-encoded transmembrane protein ORF3 lacks the major promoter region

Microbiology ◽  
2009 ◽  
Vol 155 (6) ◽  
pp. 2058-2067 ◽  
Author(s):  
Yoshiko Ishii ◽  
Shigeyuki Kakizawa ◽  
Ayaka Hoshi ◽  
Kensaku Maejima ◽  
Satoshi Kagiwada ◽  
...  
Keyword(s):  
Promoter Region ◽  
Transmembrane Protein ◽  
Immunohistochemical Analysis ◽  
The Other ◽  
Insect Host ◽  
Gene Encoding ◽  
Phytopathogenic Bacterium ◽  
Orf3 Protein ◽  
Promoter Sequences

‘Candidatus Phytoplasma asteris’, onion yellows strain (OY), a mildly pathogenic line (OY-M), is a phytopathogenic bacterium transmitted by Macrosteles striifrons leafhoppers. OY-M contains two types of plasmids (EcOYM and pOYM), each of which possesses a gene encoding the putative transmembrane protein, ORF3. A non-insect-transmissible line of this phytoplasma (OY-NIM) has the corresponding plasmids (EcOYNIM and pOYNIM), but pOYNIM lacks orf3. Here we show that in OY-M, orf3 is transcribed from two putative promoters and that on EcOYNIM, one of the promoter sequences is mutated and the other deleted. We also show by immunohistochemical analysis that ORF3 is not expressed in OY-NIM-infected plants. Moreover, ORF3 protein seems to be preferentially expressed in OY-M-infected insects rather than in plants. We speculate that ORF3 may play a role in the interactions of OY with its insect host.

Mitochondrial permeability to chloride ion

1975 ◽  
Vol 228 (1) ◽  
pp. 122-126 ◽  
Author(s):  
MW Weiner
Keyword(s):  
Rat Liver ◽  
Chloride Transport ◽  
Biological Membranes ◽  
Chloride Ion ◽  
The Other ◽  
Beef Heart ◽  
Inner Membrane ◽  
Mitochondrial Permeability ◽  
Mitochondrial Inner Membrane ◽  
Chloride Salts

It is generally accepted that the inner membrane of the mitchondrion is not penetrated by chloride ion, in contrast to other biological membranes which are chloride permeable. In this report mitochondrial permeablity to chloride ion has been reevaluated by the measurement of passive swelling in isotonic chloride-containing solutions in the presence of an uncoupling agent. Under these conditions, mitochondria prepared from rat liver or beef heart show a definite uptake of wide variety of chloride salts. Mitochondrial chloride transport appears to be electrogenic, as is the transmembrane movement of the other halides. Therefore, the mitochondrial inner membrane shares with other biological membranes a definite permeability to this ubiquitous anion.

scholarly journals The role of second coordination-sphere interactions in incommensurately modulated structures, using β-K5Yb(MoO4)4 as an example

2005 ◽  
Vol 61 (4) ◽  
pp. 400-406 ◽  
Author(s):  
Alla Arakcheeva ◽  
Gervais Chapuis ◽  
Vâclav Petricek ◽  
Vladimir Morozov
Keyword(s):  
Coordination Sphere ◽  
Driving Force ◽  
The Other ◽  
Structure Model ◽  
Unit Cell Parameters ◽  
Cell Parameters ◽  
The Third ◽  
Modulated Structures ◽  
Coordination Spheres

The incommensurate palmierite-like structure of β-K5Yb(MoO4)4, potassium ytterbium tetramolydate, has been refined in the (3 + 1)-dimensional monoclinic superspace group X2/m(0ρ0)00, with X = [0 0 0 0; ½ ½ 0 0; 0 0 ½ ½; ½ ½ ½ ½] and the unit-cell parameters a = 10.4054 (16), b = 6.1157 (12), c = 19.7751 (18) Å, β = 136.625 (10)°; q = 0.6354 (30)b*. The occupations of the K and Yb atomic positions are described by crenel functions. The structure model reveals a balanced interaction between the atoms of the first and second coordination spheres. It is shown that the third coordination sphere should not be neglected in studies of modulated structures. The ordering of the K and Yb atoms appears to be the driving force for the modulation of all the other atoms.

scholarly journals Diaqua(nitrato-κ2O,O′)bis(L-valine-κO)lead(II) nitrate at 296 K

IUCrData ◽  
2016 ◽  
Vol 1 (4) ◽  
Author(s):  
Sylvain Bernès ◽  
Laura Gasque
Keyword(s):  
Low Temperature ◽  
Bond Length ◽  
Coordination Number ◽  
Coordination Sphere ◽  
Title Complex ◽  
The Other ◽  
Methyl Group ◽  
Space Group ◽  
Polymeric Nature ◽  
Other Hand

The structure of the title complex, [Pb(NO3)(C5H11NO2)2(H2O)2]NO3, had been determined previously at 173 and 193 K, and is now reported at 296 K, in the same space group. The main difference with the low-temperature structures is that a methyl group of one valine ligand is clearly disordered over two positions, for which the occupancies converged to 0.56 (3) and 0.44 (3). Bond-length variations within the coordination sphere of PbIIas a function ofTare difficult to assess because uncertainties on these parameters are high. On the other hand, Pb...O distances above 2.9 Å cannot be assigned unambiguously to formal Pb—O bonds. As a consequence, the polymeric nature of the complex previously described at 173 K is uncertain, as well as the actual coordination number of PbII, and it is thus not possible to determine if the metal environment is holo- or hemidirected.

scholarly journals Pathway of Glucose Catabolism by Strain VeGlc2, an Anaerobe Belonging to the Verrucomicrobiales Lineage of Bacterial Descent

1998 ◽  
Vol 64 (12) ◽  
pp. 4830-4833 ◽  
Author(s):  
Peter H. Janssen
Keyword(s):  
Electron Transport ◽  
Enzyme Activities ◽  
The Other ◽  
Difference Spectra ◽  
Glucose Catabolism ◽  
Cell Extracts ◽  
In Vitro Measurements ◽  
End Products ◽  
Reductive Pathway

ABSTRACT Strain VeGlc2, an anaerobic ultramicrobacterium belonging to theVerrucomicrobiales lineage of bacterial descent, fermented glucose to acetate, propionate, succinate, and CO2. The distribution of radiolabel in the fermentation end products produced from position-labelled glucose and in vitro measurements of enzyme activities in crude cell extracts prepared from glucose-grown cells showed that glucose was metabolized via the Embden-Meyerhof-Parnas pathway. The 6-phosphofructokinase (EC 2.7.1.90 ) activity required pyrophosphate as the phosphoryl donor, and ATP could not replace pyrophosphate. The other enzyme activities were those of a classical Embden-Meyerhof-Parnas pathway. 14CO2 was incorporated into propionate and succinate, suggesting that a carboxylation reaction rather than a transcarboxylation reaction was involved in the reductive pathway leading to succinate and propionate. Difference spectra showed that a type b cytochrome was present, which could be involved in electron transport in the reductive pathway.

scholarly journals Using FluoZin-3 and fura-2 to monitor acute accumulation of free intracellular Cd2+ in a pancreatic beta cell line

BioMetals ◽  
2019 ◽  
Vol 32 (6) ◽  
pp. 951-964 ◽  
Author(s):  
Latha M. Malaiyandi ◽  
Harsh Sharthiya ◽  
Ameir N. Barakat ◽  
Joshua R. Edwards ◽  
Kirk E. Dineley
Keyword(s):  
Beta Cell ◽  
Pancreatic Beta Cells ◽  
Pancreatic Beta Cell ◽  
The Other ◽  
Selective Detection ◽  
Fluorescent Indicators ◽  
Voltage Gated ◽  
Fura 2 ◽  
Voltage Gated Calcium Channels ◽  
Beta Cell Line

AbstractThe understanding of cellular Cd2+ accumulation and toxicity is hampered by a lack of fluorescent indicators selective for intracellular free Cd2+ ([Cd2+]i). In this study, we used depolarized MIN6 mouse pancreatic beta cells as a model for evaluating [Cd2+]i detection with commercially available fluorescent probes, most of which have been traditionally used to visualize [Ca2+]i and [Zn2+]i. We trialed a panel of 12 probes including fura-2, FluoZin-3, Leadmium Green, Rhod-5N, indo-1, Fluo-5N, and others. We found that the [Zn2+]i probe FluoZin-3 and the traditional [Ca2+]i probe fura-2 responded most consistently and robustly to [Cd2+]i accumulation mediated by voltage-gated calcium channels. While selective detection of [Cd2+]i by fura-2 required the omission of Ca2+ from extracellular buffers, FluoZin-3 responded to [Cd2+]i similarly in the presence or absence of extracellular Ca2+. Furthermore, we showed that FluoZin-3 and fura-2 can be used together for simultaneous monitoring of [Ca2+]i and [Cd2+]i in the same cells. None of the other fluorophores tested were effective [Cd2+]i detectors in this model.

Structural and spectroscopic studies of transition metal nitrite complexes. X. Crystal structures of cis-Bis(2,2'-bipyridine)(nitrito-O,O')nickel(II) nitrate and hydrated Tris(2,2'-bipyridine)nickel(II) nitrite/nitrate and sulfate. Stereochemistry of the [M(bidentate ligand)2(bidentate ligand')1] system

1981 ◽  
Vol 34 (10) ◽  
pp. 2177 ◽  
Author(s):  
AJ Finney ◽  
MA Hitchman ◽  
DL Kepert ◽  
CL Raston ◽  
GL Rowbottom ◽  
...  
Keyword(s):  
Transition Metal ◽  
Crystal Structures ◽  
Coordination Sphere ◽  
Nickel Atom ◽  
Spectroscopic Studies ◽  
Bidentate Ligand ◽  
The Other ◽  
Bidentate Ligands ◽  
Nitrite Nitrate ◽  
Oxygen Atoms

The crystal structures of the title compounds are reported. In all cases, the coordination sphere of the nickel atom comprises three bidentate ligands. In (1), [Ni(bpy)2(O2N)] NO3, (Ni-N) is 2.M2 � although there are small differences between those nitrogen atoms trans to the nitrite oxygen atoms and the other two. (Ni-O) is 2.12 �. In (2), [Ni(bpy)3] NO2/NO3,xH2O, and (3), [Ni(bpy)3]- SO4,7.5H2O, a redetermination, Ni-N is shown to be c. 2.09 �; serious disorder is present among the non-cationic components of (2), precluding a definite assignment of stoichiometry.

A copper transcription factor, AfMac1, regulates both iron and copper homeostasis in the opportunistic fungal pathogen Aspergillus fumigatus

2018 ◽  
Vol 475 (17) ◽  
pp. 2831-2845 ◽  
Author(s):  
Yong-Sung Park ◽  
Suzie Kang ◽  
Hyewon Seo ◽  
Cheol-Won Yun
Keyword(s):  
Gene Expression ◽  
Aspergillus Fumigatus ◽  
Fungal Pathogen ◽  
Promoter Region ◽  
Regulation Of Gene Expression ◽  
Copper Homeostasis ◽  
Living Cells ◽  
The Other ◽  
Binding Motif ◽  
Opportunistic Fungal Pathogen

Although iron and copper are co-ordinately regulated in living cells, the homeostatic effects of each of these metals on the other remain unknown. Here, we show the function of AfMac1, a transcriptional activator of the copper and iron regulons of Aspergillus fumigatus, on the interaction between iron and copper. In addition to the copper-specific AfMac1-binding motif 5′-TGTGCTCA-3′ found in the promoter region of ctrC, the iron-specific AfMac1-binding motif 5′-AT(C/G)NN(A/T)T(A/C)-3′ was identified in the iron regulon but not in the copper regulon by ChIP sequence analysis. Furthermore, mutation of the AfMac1-binding motif of sit1 eliminated AfMac1-mediated sit1 up-regulation. Interestingly, the regulation of gene expression in the iron regulon by AfMac1 was not affected by copper and vice versa. AfMac1 localized to the nucleus under iron- or copper-depleted conditions, and AfMac1 was mostly detected in the cytoplasm under iron- or copper-replete conditions. Taken together, these results suggest that A. fumigatus independently regulates iron and copper homeostasis in a manner that involves AfMac1 and mutual interactions.

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