scholarly journals Control of zinc homeostasis in Agrobacterium tumefaciens via zur and the zinc uptake genes znuABC and zinT

Microbiology ◽  
2014 ◽  
Vol 160 (11) ◽  
pp. 2452-2463 ◽  
Author(s):  
Sakkarin Bhubhanil ◽  
Panida Sittipo ◽  
Paweena Chaoprasid ◽  
Sumontha Nookabkaew ◽  
Rojana Sukchawalit ◽  
...  
Keyword(s):  
Agrobacterium Tumefaciens ◽  
Dominant Role ◽  
Zinc Content ◽  
Zinc Uptake ◽  
Zinc Homeostasis ◽  
Dependent Manner ◽  
Transporter Family ◽  
Zinc Depletion ◽  
Zinc Uptake Regulator ◽  
Dose Dependent

The Agrobacterium tumefaciens zinc uptake regulator (Zur) was shown to negatively regulate the zinc uptake genes znuABC, encoding a zinc transport system belonging to the ATP-binding cassette (ABC) transporter family, and zinT, which encodes a periplasmic zinc-binding protein. The expression of znuABC and zinT was inducible when cells were grown in medium containing a metal chelator (EDTA), and this induction was shown to be specific for zinc depletion. The expression of znuABC was reduced in response to increased zinc in a dose-dependent manner, and zinT had a less pronounced but similar pattern of zinc-regulated expression. The inactivation of zur led to constitutively high expression of znuABC and zinT. In addition, a zur mutant had an increased total zinc content compared to the WT NTL4 strain, whereas the inactivation of zinT caused a reduction in the total zinc content. The zinT gene is shown to play a dominant role and to be more important than znuA and znuB for A. tumefaciens survival under zinc deprivation. ZinT can function even when ZnuABC is inactivated. However, mutations in zur, znuA, znuB or zinT did not affect the virulence of A. tumefaciens.

Effects of Low Molecular Weight Heparin and Unfragmented Heparin on Induction of Osteoporosis in Rats

1990 ◽  
Vol 63 (03) ◽  
pp. 505-509 ◽  
Author(s):  
Thomas Mätzsch ◽  
David Bergqvist ◽  
Ulla Hedner ◽  
Bo Nilsson ◽  
Per Østergaar
Keyword(s):  
Molecular Weight ◽  
Bone Mineral ◽  
Low Molecular Weight Heparin ◽  
Zinc Content ◽  
Low Molecular Weight ◽  
Dependent Manner ◽  
Bone Mineral Mass ◽  
Bone Ash ◽  
Dose Dependent ◽  
Mineral Mass

SummaryA comparison between the effect of low molecular weight heparin (LMWH) and unfragmented heparin (UH) on induction of osteoporosis was made in 60 rats treated with either UH (2 IU/ g b w), LMWH in 2 doses (2 Xal U/g or 0.4 Xal U/g) or placebo (saline) for 34 days. Studied variables were: bone mineral mass in femora; fragility of humera; zinc and calcium levels in serum and bone ash and albumin in plasma. A significant reduction in bone mineral mass was found in all heparin-treated rats. There was no difference between UH and LMWH in this respect. The effect was dose-dependent in LMWH-treated animals. The zinc contents in bone ash were decreased in all heparin-treated rats as compared with controls. No recognizable pattern was seen in alterations of zinc or calcium in serum. The fragility of the humera, tested as breaking strength did not differ between treatment groups and controls. In conclusion, if dosed according to similar factor Xa inhibitory activities, LMWH induces osteoporosis to the same extent as UH and in a dose-dependent manner. The zinc content in bone ash was decreased after heparin treatment, irrespective of type of heparin given.

Zinc Uptake Regulator (zur) Gene Involved in Zinc Homeostasis and Virulence of Xanthomonas oryzae pv. oryzae in Rice

2007 ◽  
Vol 54 (4) ◽  
pp. 307-314 ◽  
Author(s):  
Wanfeng Yang ◽  
Yan Liu ◽  
Lei Chen ◽  
Tongchun Gao ◽  
Baishi Hu ◽  
...  
Keyword(s):  
Zinc Uptake ◽  
Xanthomonas Oryzae ◽  
Zinc Homeostasis ◽  
Zinc Uptake Regulator

scholarly journals Functional Definition and Global Regulation of Zur, a Zinc Uptake Regulator in a Streptococcus suis Serotype 2 Strain Causing Streptococcal Toxic Shock Syndrome

2008 ◽  
Vol 190 (22) ◽  
pp. 7567-7578 ◽  
Author(s):  
Youjun Feng ◽  
Ming Li ◽  
Huimin Zhang ◽  
Beiwen Zheng ◽  
Huiming Han ◽  
...  
Keyword(s):  
Toxic Shock Syndrome ◽  
Streptococcus Suis ◽  
Gene Replacement ◽  
Zinc Uptake ◽  
Zinc Homeostasis ◽  
Differentially Expressed ◽  
Streptococcal Toxic Shock Syndrome ◽  
Toxic Shock ◽  
Physiological Tests ◽  
Zinc Uptake Regulator

ABSTRACT Zinc is an essential trace element for all living organisms and plays pivotal roles in various cellular processes. However, an excess of zinc is extremely deleterious to cells. Bacteria have evolved complex machineries (such as efflux/influx systems) to control the concentration at levels appropriate for the maintenance of zinc homeostasis in cells and adaptation to the environment. The Zur (zinc uptake regulator) protein is one of these functional members involved in the precise control of zinc homeostasis. Here we identified a zur homologue designated 310 from Streptococcus suis serotype 2, strain 05ZYH33, a highly invasive isolate causing streptococcal toxic shock syndrome. Biochemical analysis revealed that the protein product of gene 310 exists as a dimer form and carries zinc ions. An isogenic gene replacement mutant of gene 310, the Δ310 mutant, was obtained by homologous recombination. Physiological tests demonstrated that the Δ310 mutant is specifically sensitive to Zn2+, while functional complementation of the Δ310 mutant can restore its duration capability, suggesting that 310 is a functional member of the Zur family. Two-dimensional electrophoresis indicated that nine proteins in the Δ310 mutant are overexpressed in comparison with those in the wild type. DNA microarray analyses suggested that 121 genes in the Δ310 mutant are affected, of which 72 genes are upregulated and 49 are downregulated. The transcriptome of S. suis serotype 2 with high Zn2+ concentrations also showed 117 differentially expressed genes, with 71 upregulated and 46 downregulated. Surprisingly, more than 70% of the genes differentially expressed in the Δ310 mutant were the same as those in S. suis serotype 2 that were differentially expressed in response to high Zn2+ concentration, consistent with the notion that 310 is involved in zinc homeostasis. We thus report for the first time a novel zinc-responsive regulator, Zur, from Streptococcus suis serotype 2.

scholarly journals The Zinc-Responsive Regulator Zur Controls a Zinc Uptake System and Some Ribosomal Proteins in Streptomyces coelicolor A3(2)

2007 ◽  
Vol 189 (11) ◽  
pp. 4070-4077 ◽  
Author(s):  
Jung-Ho Shin ◽  
So-Young Oh ◽  
Soon-Jong Kim ◽  
Jung-Hye Roe
Keyword(s):  
Ribosomal Proteins ◽  
Streptomyces Coelicolor ◽  
Regulatory System ◽  
Repeat Sequence ◽  
Zinc Uptake ◽  
Zinc Homeostasis ◽  
Transport Systems ◽  
Binding Motif ◽  
Uptake System ◽  
Zinc Depletion

ABSTRACT In various bacteria, Zur, a zinc-specific regulator of the Fur family, regulates genes for zinc transport systems to maintain zinc homeostasis. It has also been suggested that Zur controls zinc mobilization by regulating some ribosomal proteins. The antibiotic-producing soil bacterium Streptomyces coelicolor contains four genes for Fur family regulators, and one (named zur) is located downstream of the znuACB operon encoding a putative zinc uptake transporter. We found that zinc specifically repressed the level of znuA transcripts and that this level was derepressed in a Δzur mutant. Purified Zur existing as homodimers bound to the znuA promoter region in the presence of zinc, confirming the role of Zur as a zinc-responsive repressor. We analyzed transcripts for paralogous forms of ribosomal proteins L31 (RpmE1 and RpmE2) and L33 (RpmG2 and RpmG3) for their dependence on Zur and found that RpmE2 and RpmG2 with no zinc-binding motif of conserved cysteines (C's) were negatively regulated by Zur. C-negative RpmG3 and C-positive RpmE1 were not regulated by Zur. Instead, they were regulated by the sigma factor σR as predicted from their promoter sequences. The rpmE1 and rpmG3 genes were partially induced by EDTA in a manner dependent on σR, suggesting that zinc depletion may stimulate the σR regulatory system. This finding reflects a link between thiol-oxidizing stress and zinc depletion. We determined the Zur-binding sites within znuA and rpmG2 promoter regions by footprinting analyses and identified a consensus inverted repeat sequence (TGaaAatgatTttCA, where uppercase letters represent the nucleotides common to all sites analyzed). This sequence closely matches that for mycobacterial Zur and allows the prediction of more genes in the Zur regulon.

scholarly journals Bacterial zinc uptake regulator proteins and their regulons

2018 ◽  
Vol 46 (4) ◽  
pp. 983-1001 ◽  
Author(s):  
Alevtina Mikhaylina ◽  
Amira Z. Ksibe ◽  
David J. Scanlan ◽  
Claudia A. Blindauer
Keyword(s):  
Intracellular Trafficking ◽  
Ribosomal Proteins ◽  
Pathogenic Bacteria ◽  
Transcriptional Regulators ◽  
Research Area ◽  
Essential Elements ◽  
Zinc Uptake ◽  
Zinc Homeostasis ◽  
Dna Binding Affinity ◽  
Zinc Uptake Regulator

All organisms must regulate the cellular uptake, efflux, and intracellular trafficking of essential elements, including d-block metal ions. In bacteria, such regulation is achieved by the action of metal-responsive transcriptional regulators. Among several families of zinc-responsive transcription factors, the ‘zinc uptake regulator’ Zur is the most widespread. Zur normally represses transcription in its zinc-bound form, in which DNA-binding affinity is enhanced allosterically. Experimental and bioinformatic searches for Zur-regulated genes have revealed that in many cases, Zur proteins govern zinc homeostasis in a much more profound way than merely through the expression of uptake systems. Zur regulons also comprise biosynthetic clusters for metallophore synthesis, ribosomal proteins, enzymes, and virulence factors. In recognition of the importance of zinc homeostasis at the host–pathogen interface, studying Zur regulons of pathogenic bacteria is a particularly active current research area.

Effects of NO-Donors on Thrombus Formation and Microcirculation in Cerebral Vessels of the Rat

1996 ◽  
Vol 76 (01) ◽  
pp. 111-117 ◽  
Author(s):  
Yasuto Sasaki ◽  
Junji Seki ◽  
John C Giddings ◽  
Junichiro Yamamoto
Keyword(s):  
Blood Flow ◽  
Thrombus Formation ◽  
Dependent Manner ◽  
Red Cell ◽  
Cell Velocity ◽  
Red Cell Velocity ◽  
The Mean ◽  
Wall Shear ◽  
Dose Dependent

SummarySodium nitroprusside (SNP) and 3-morpholinosydnonimine (SIN-1), are known to liberate nitric oxide (NO). In this study the effects of SNP and SIN-1 on thrombus formation in rat cerebral arterioles and venules in vivo were assessed using a helium-neon (He-Ne) laser. SNP infused at doses from 10 Μg/kg/h significantly inhibited thrombus formation in a dose dependent manner. This inhibition of thrombus formation was suppressed by methylene blue. SIN-1 at a dose of 100 Μg/kg/h also demonstrated a significant antithrombotic effect. Moreover, treatment with SNP increased vessel diameter in a dose dependent manner and enhanced the mean red cell velocity measured with a fiber-optic laser-Doppler anemometer microscope (FLDAM). Blood flow, calculated from the mean red cell velocity and vessel diameters was increased significantly during infusion. In contrast, mean wall shear rates in the arterioles and venules were not changed by SNP infusion. The results indicated that SNP and SIN-1 possessed potent antithrombotic activities, whilst SNP increased cerebral blood flow without changing wall shear rate. The findings suggest that the NO released by SNP and SIN-1 may be beneficial for the treatment and protection of cerebral infarction

Melatonin actions in the heart; more than a hormone

2018 ◽  
Vol 1 (1) ◽  
pp. 21-26 ◽  
Author(s):  
Darío Acuña-Castroviejo ◽  
Maria T Noguiera-Navarro ◽  
Russel J Reiter ◽  
Germaine Escames
Keyword(s):  
Cell Membranes ◽  
Myocardial Cell ◽  
Rat Tissues ◽  
Dependent Manner ◽  
Broad Distribution ◽  
Multiple Organs ◽  
High Doses ◽  
Extrapineal Melatonin ◽  
Dose Dependent ◽  
Different Doses

Due to the broad distribution of extrapineal melatonin in multiple organs and tissues, we analyzed the presence and subcellular distribution of the indoleamine in the heart of rats. Groups of sham-operated and pinealectomized rats were sacrificed at different times along the day, and the melatonin content in myocardial cell membranes, cytosol, nuclei and mitochondria, were measured. Other groups of control animals were treated with different doses of melatonin to monitor its intracellular distribution. The results show that melatonin levels in the cell membrane, cytosol, nucleus, and mitochondria vary along the day, without showing a circadian rhythm. Pinealectomized animals trend to show higher values than sham-operated rats. Exogenous administration of melatonin yields its accumulation in a dose-dependent manner in all subcellular compartments analyzed, with maximal concentrations found in cell membranes at doses of 200 mg/kg bw melatonin. Interestingly, at dose of 40 mg/kg b.w, maximal concentration of melatonin was reached in the nucleus and mitochondrion. The results confirm previous data in other rat tissues including liver and brain, and support that melatonin is not uniformly distributed in the cell, whereas high doses of melatonin may be required for therapeutic purposes.

Evaluating the Proposed Mechanism by Which Atorvastatin Can Protect Renal Tissue against Contrast Media: An Animal study

2019 ◽  
pp. 75-84
Keyword(s):  
Contrast Media ◽  
Kidney Injury ◽  
Saline Group ◽  
Pleiotropic Effect ◽  
Renal Tissue ◽  
Male Rats ◽  
Dependent Manner ◽  
Group 2 ◽  
Dose Dependent ◽  
Media Group

Contrast- induced nephropathy (CIN) is an elevation of serum creatinine of ≥ 0.5 mg/dL from baseline after two to three days of exposure to contrast substance if there is no other cause for acute kidney injury. Atorvastatin may protect normal kidney physiology from contrast- induced kidney injury by effects unrelated to hypolipidemia termed pleiotropic effect by decline of endothelin production, angiotensin system down regulation, and under expression of endothelial adhesion molecules. This study was conducted to assess the strategy by which atorvastatin can achieve protective effect for kidneys after exposure to contrast media in an animal model. A 40 male rats were distributed randomly into 4 groups; ten rats for each: group (1): given normal saline; group (2): CIN group given iopromide as contrast media; group (3): given atorvastatin (20mg/kg) and iopromide; and group (4): given atorvastatin (40mg/kg) and iopromide. Blood collected by cardiac puncture for detection of serum glutathione, malondialdehyde, matrix metalloproteinase-9, and interleukin-18. The results have shown a significant increase in inflammatory and oxidative stress markers in contrast media group, and significant reduction in these markers in atorvastatin treated groups, in a dose-dependent manner. As conclusion, atorvastatin mechanism for protection against CIN in a dose-dependent manner can mediate by anti-inflammatory and antioxidant effects.

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