scholarly journals The salivary, metal-binding peptide histatin-5 buffers extracellular copper availability

2022 ◽  
Author(s):  
Louisa Stewart ◽  
YoungJin Hong ◽  
Isabel Holmes ◽  
Samantha Firth ◽  
Jack Bolton ◽  
...  
Keyword(s):  
Mutant Strain ◽  
Metal Binding ◽  
Group A Streptococcus ◽  
Negative Effects ◽  
Histatin 5 ◽  
High Affinity ◽  
Nutritional Immunity ◽  
Zn Uptake ◽  
Inducible Genes ◽  
Zn Availability

The family of human salivary histidine-rich peptides known as histatins bind zinc (Zn) and copper (Cu), but whether they contribute to nutritional immunity by influencing Zn and/or Cu availability has not been examined. We hypothesised that histatin-5 (Hst5) limits Zn availability (and promotes bacterial Zn starvation) and/or raises Cu availability (and promotes bacterial Cu poisoning). To test this hypothesis, Group A Streptococcus (GAS), which colonises the human oropharynx, was used as a model bacterium. Contrary to our hypothesis, Hst5 did not strongly influence Zn availability. This peptide did not induce expression of Zn uptake genes in GAS, nor did it suppress growth of an ΔadcAI mutant strain that is impaired in Zn uptake. Equilibrium competition measurements confirmed that Hst5 binds Zn weakly and does not compete with the high-affinity Zn uptake protein AdcAI for binding Zn. By contrast, Hst5 bound Cu with a high affinity and strongly influenced Cu availability. However, contrary to our hypothesis, Hst5 did not promote Cu toxicity. Instead, this peptide suppressed expression of Cu-inducible genes in GAS, stopped intracellular accumulation of Cu, and rescued growth of a ΔcopA mutant strain that is impaired in Cu efflux in the presence of added Cu. These findings led us to propose a new role for Hst5 and salivary histatins as major Cu buffers in saliva that reduce the potential negative effects of Cu exposure to microbes. We speculate that histatins promote oral and oropharyngeal health by contributing to microbial homeostasis in these host niches.

scholarly journals Zinc Uptake by Plants as Affected by Fertilization with Zn Sulfate, Phosphorus Availability, and Soil Properties

Agronomy ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 390
Author(s):  
Ramiro Recena ◽  
Ana M. García-López ◽  
Antonio Delgado
Keyword(s):  
Soil Properties ◽  
Zn Deficiency ◽  
Acid Extraction ◽  
P Availability ◽  
Positive Role ◽  
Yield And Quality ◽  
Zn Uptake ◽  
Use Efficiency ◽  
Crystalline Oxides ◽  
Zn Availability

Zinc (Zn) deficiency constrains crop yield and quality, but soil factors influencing Zn availability to plants and reactions of applied Zn fertilizer are not fully understood. This work is aimed at studying Zn availability in soil and the use efficiency of Zn fertilizers by plants as affected by soil properties and particularly by soil available P. We performed a pot experiment involving four consecutive crops fertilized with Zn sulfate using 36 soils. The cumulative Zn uptake and dry matter yield in the four crops increased with increased initial diethylenetriamine pentaacetic acid extraction of Zn (DTPA-Zn) (R2 = 0.75 and R2 = 0.61; p < 0.001). The initial DTPA-Zn increased with increased Olsen P (R2 = 0.41; p < 0.001) and with increased ratio of Fe in poorly crystalline to Fe in crystalline oxides (R2 = 0.58; p < 0.001). DTPA-Zn decreased with increased cumulative Zn uptake, but not in soils with DTPA-Zn < 0.5 mg kg−1. Overall, the available Zn is more relevant in explaining Zn uptake by plants than applied Zn sulfate. However, in Zn-deficient soils, Zn fertilizer explained most of the Zn uptake by crops. Poorly crystalline Fe oxides and P availability exerted a positive role on Zn availability to plants in soil.

scholarly journals Green manure effect on the ability of native and inoculated soil bacteria to mobilize zinc for wheat uptake (Triticum aestivum L.)

2021 ◽  
Author(s):  
Benjamin Costerousse ◽  
Joel Quattrini ◽  
Roman Grüter ◽  
Emmanuel Frossard ◽  
Cécile Thonar
Keyword(s):  
Green Manure ◽  
Soil Bacteria ◽  
Triticum Aestivum L ◽  
Zn Deficiency ◽  
X Ray ◽  
Zn Uptake ◽  
Native Soil ◽  
Soil Zn ◽  
Zn Availability ◽  
Stimulation Of

Abstract Purpose Green manuring can increase the plant available fraction of zinc (Zn) in soil, making it a potential approach to increase wheat Zn concentrations and fight human Zn deficiency. We tested whether green manure increases the ability of both the native soil bacteria and inoculated Zn solubilizing bacteria (ZSB) to mobilize Zn. Methods Wheat was grown in a pot experiment with the following three factors (with or without); (i) clover addition; (ii) soil x-ray irradiation (i.e. elimination of the whole soil biota followed by re-inoculation with the native soil bacteria); and (iii) ZSB inoculation. The incorporation of clover in both the irradiated and the ZSB treatments allowed us to test green manure effects on the mobilization of Zn by indigenous soil bacteria as well as by inoculated strains. Results Inoculation with ZSB did neither increase soil Zn availability nor wheat Zn uptake. The highest soil Zn availabilities were found when clover was incorporated, particularly in the irradiated soils (containing only soil bacteria). This was partly associated with the stimulation of bacterial activity during the decomposition of the incorporated green manure. Conclusion The results support that the activity of soil bacteria is intimately involved in the mobilization of Zn following the incorporation of green manure.

A consensus zinc finger peptide: design, high-affinity metal binding, a pH-dependent structure, and a His to Cys sequence variant

1991 ◽  
Vol 113 (12) ◽  
pp. 4518-4523 ◽  
Author(s):  
Beth Allyn Krizek ◽  
Barbara T. Amann ◽  
Valda J. Kilfoil ◽  
Denise L. Merkle ◽  
Jeremy M. Berg
Keyword(s):  
Zinc Finger ◽  
Metal Binding ◽  
Sequence Variant ◽  
Peptide Design ◽  
High Affinity ◽  
Ph Dependent ◽  
Zinc Finger Peptide

scholarly journals Metal binding spectrum and model structure of theBacillus anthracisvirulence determinant MntA

Metallomics ◽  
2015 ◽  
Vol 7 (10) ◽  
pp. 1407-1419 ◽  
Author(s):  
Elena Vigonsky ◽  
Inbar Fish ◽  
Nurit Livnat-Levanon ◽  
Elena Ovcharenko ◽  
Nir Ben-Tal ◽  
...  
Keyword(s):  
Bacillus Anthracis ◽  
Metal Binding ◽  
Model Structure ◽  
High Affinity ◽  
Virulence Determinant ◽  
System P

TheBacillus anthracisvirulence determinant MntA is a high-affinity manganese system.

scholarly journals Modulation of Symbiotic Compatibility by Rhizobial Zinc Starvation Machinery

mBio ◽  
2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Pan Zhang ◽  
Biliang Zhang ◽  
Jian Jiao ◽  
Shi-Qi Dai ◽  
Wen-Xin Chen ◽  
...  
Keyword(s):  
Sustainable Agriculture ◽  
Host Range ◽  
Zinc Transporter ◽  
Zinc Homeostasis ◽  
Broad Host Range ◽  
Host Immune System ◽  
High Affinity ◽  
Nutritional Immunity ◽  
Accessory Genes ◽  
Legume Symbiosis

ABSTRACT Pathogenic bacteria need high-affinity zinc uptake systems to counteract the nutritional immunity exerted by infected hosts. However, our understanding of zinc homeostasis in mutualistic systems such as the rhizobium-legume symbiosis is limited. Here, we show that the conserved high-affinity zinc transporter ZnuABC and accessory transporter proteins (Zip1, Zip2, and c06450) made cumulative contributions to nodulation of the broad-host-range strain Sinorhizobium fredii CCBAU45436. Zur acted as a zinc-dependent repressor for the znuC-znuB-zur operon, znuA, and c06450 by binding to the associated Zur box, but did not regulate zip1 and zip2. ZnuABC was the major zinc transporter. Combined mutants lacking znuA and one of the three accessory genes had more severe defects in nodulation and growth under zinc starvation conditions than the znuA mutant, though rhizoplane colonization by these mutants was not impaired. In contrast to the elite strain CCBAU45436, more drastic symbiotic defects were observed for the znuA mutants of other Sinorhizobium strains, which lack at least one of the three accessory genes in their genomes and are characterized by their limited host range and geographical distribution. The znu-derived mutants showed a higher expression level of nod genes involved in Nod factor biosynthesis and a reduced expression of genes encoding a type three secretion system and its effector NopP, which can interfere with the host immune system. Application of exogenous zinc restored the nodulation ability of these znu-derived mutants. Therefore, the conserved ZnuABC and accessory components in the zinc starvation machinery play an important role in modulating symbiotic compatibility. IMPORTANCE The rhizobium-legume symbiosis contributes around 65% of biological nitrogen fixation in agriculture systems and is critical for sustainable agriculture by reducing the amount of chemical nitrogen fertilizer being used. Rhizobial inocula have been commercialized for more than 100 years, but the efficiency of inoculation can vary among legume cultivars, field sites, and years. These long-lasting challenging problems impede the establishment of a sustainable agriculture, particularly in developing countries. Here, we report that rhizobial zinc starvation machinery containing a conserved high-affinity zinc transporter and accessory components makes cumulative contributions to modulating rhizobial symbiotic compatibility. This work highlights a critical role of largely unexplored nutritional immunity in the rhizobium-legume symbiosis, which makes zinc starvation machinery an attractive target for improving rhizobial symbiotic compatibility.

scholarly journals Expression Microarray and Mouse Virulence Analysis of Four Conserved Two-Component Gene Regulatory Systems in Group A Streptococcus

2006 ◽  
Vol 74 (2) ◽  
pp. 1339-1351 ◽  
Author(s):  
Izabela Sitkiewicz ◽  
James M. Musser
Keyword(s):  
Mutant Strain ◽  
Group A Streptococcus ◽  
Expression Microarray ◽  
Regulatory Systems ◽  
Significant Difference ◽  
Two Component ◽  
Mutant Strains ◽  
Group A ◽  
Gene Regulatory ◽  
Component Gene

ABSTRACT Group A streptococcus (GAS) is a gram-positive human bacterial pathogen that causes diseases ranging from relatively mild epithelial cell surface infections to life-threatening invasive episodes. Much is known about the extracellular molecules that contribute to host-pathogen interactions, but in contrast, far less information is available about regulatory genes that control the expression of individual or multiple GAS virulence factors. The eight GAS genomes that have been sequenced have 12 conserved two-component gene regulatory systems (TCSs), but only 3 of these 12 have been studied in detail. Using an allelic replacement strategy with a nonpolar cassette, we inactivated the response regulator of four TCSs that have only weak homology with TCS genes of known or inferred function in other bacteria. The mutant strains were analyzed by expression microarray analysis at four time points and tested in two mouse infection models. Each TCS influenced expression (directly or indirectly) of 12 to 41% of all chromosomal genes, as assessed by growth in Todd-Hewitt broth and a custom Affymetrix GeneChip. None of the isogenic mutant strains was significantly altered for mouse virulence based on intraperitoneal inoculation. Similarly, compared to the wild-type strain, there was no significant difference in skin lesion size for three of the four mutants. In contrast, the ΔM5005_Spy_0680 mutant strain produced significantly larger abscesses after subcutaneous inoculation into mice, consistent with a hypervirulence phenotype. The mutant strain had significantly higher in vitro expression of several proven and putative virulence genes, including scpA, encoding a peptidase that inactivates complement protein C5a. Together, the data provide new information about previously uncharacterized GAS TCSs.

scholarly journals Znu Is the Predominant Zinc Importer in Yersinia pestis during In Vitro Growth but Is Not Essential for Virulence

2010 ◽  
Vol 78 (12) ◽  
pp. 5163-5177 ◽  
Author(s):  
Daniel C. Desrosiers ◽  
Scott W. Bearden ◽  
Ildefonso Mier ◽  
Jennifer Abney ◽  
James T. Paulley ◽  
...  
Keyword(s):  
Yersinia Pestis ◽  
Binding Protein ◽  
Bacterial Pathogens ◽  
Titration Calorimetry ◽  
Growth Defect ◽  
Uptake System ◽  
High Affinity ◽  
Zn Uptake ◽  
Low Concentrations

ABSTRACT Little is known about Zn homeostasis in Yersinia pestis, the plague bacillus. The Znu ABC transporter is essential for zinc (Zn) uptake and virulence in a number of bacterial pathogens. Bioinformatics analysis identified ZnuABC as the only apparent high-affinity Zn uptake system in Y. pestis. Mutation of znuACB caused a growth defect in Chelex-100-treated PMH2 growth medium, which was alleviated by supplementation with submicromolar concentrations of Zn. Use of transcriptional reporters confirmed that Zur mediated Zn-dependent repression and that it can repress gene expression in response to Zn even in the absence of Znu. Virulence testing in mouse models of bubonic and pneumonic plague found only a modest increase in survival in low-dose infections by the znuACB mutant. Previous studies of cluster 9 (C9) transporters suggested that Yfe, a well-characterized C9 importer for manganese (Mn) and iron in Y. pestis, might function as a second, high-affinity Zn uptake system. Isothermal titration calorimetry revealed that YfeA, the solute-binding protein component of Yfe, binds Mn and Zn with comparably high affinities (dissociation constants of 17.8 ± 4.4 nM and 6.6 ± 1.2 nM, respectively), although the complete Yfe transporter could not compensate for the loss of Znu in in vitro growth studies. Unexpectedly, overexpression of Yfe interfered with the znu mutant's ability to grow in low concentrations of Zn, while excess Zn interfered with the ability of Yfe to import iron at low concentrations; these results suggest that YfeA can bind Zn in the bacterial cell but that Yfe is incompetent for transport of the metal. In addition to Yfe, we have now eliminated MntH, FetMP, Efe, Feo, a substrate-binding protein, and a putative nickel transporter as the unidentified, secondary Zn transporter in Y. pestis. Unlike other bacterial pathogens, Y. pestis does not require Znu for high-level infectivity and virulence; instead, it appears to possess a novel class of transporter, which can satisfy the bacterium's Zn requirements under in vivo metal-limiting conditions. Our studies also underscore the need for bacterial cells to balance binding and transporter specificities within the periplasm in order to maintain transition metal homeostasis.

scholarly journals Role of Calprotectin in Withholding Zinc and Copper from Candida albicans

2017 ◽  
Vol 86 (2) ◽  
Author(s):  
Angelique N. Besold ◽  
Benjamin A. Gilston ◽  
Jana N. Radin ◽  
Christian Ramsoomair ◽  
Edward M. Culbertson ◽  
...  
Keyword(s):  
Candida Albicans ◽  
Stress Responses ◽  
Metal Binding ◽  
Content Type ◽  
Nutritional Immunity ◽  
Numerous Cell ◽  
Transcriptional Changes ◽  
Opportunistic Fungal Pathogen ◽  
First Time

ABSTRACT The opportunistic fungal pathogen Candida albicans acquires essential metals from the host, yet the host can sequester these micronutrients through a process known as nutritional immunity. How the host withholds metals from C. albicans has been poorly understood; here we examine the role of calprotectin (CP), a transition metal binding protein. When CP depletes bioavailable Zn from the extracellular environment, C. albicans strongly upregulates ZRT1 and PRA1 for Zn import and maintains constant intracellular Zn through numerous cell divisions. We show for the first time that CP can also sequester Cu by binding Cu(II) with subpicomolar affinity. CP blocks fungal acquisition of Cu from serum and induces a Cu starvation stress response involving SOD1 and SOD3 superoxide dismutases. These transcriptional changes are mirrored when C. albicans invades kidneys in a mouse model of disseminated candidiasis, although the responses to Cu and Zn limitations are temporally distinct. The Cu response progresses throughout 72 h, while the Zn response is short-lived. Notably, these stress responses were attenuated in CP null mice, but only at initial stages of infection. Thus, Zn and Cu pools are dynamic at the host-pathogen interface and CP acts early in infection to restrict metal nutrients from C. albicans.

Design and applications of methods for fluorescence detection of iron in biological systems

2002 ◽  
Vol 30 (4) ◽  
pp. 729-732 ◽  
Author(s):  
B. P. Espósito ◽  
W. Breuer ◽  
Z. I. Cabantchik
Keyword(s):  
Metal Binding ◽  
Biological Systems ◽  
Iron Chelator ◽  
Specific Cell ◽  
Iron Binding ◽  
Physiological Conditions ◽  
High Affinity ◽  
Cell Compartments ◽  
Heterogeneous Nature ◽  
Labile Iron

Fluorescence metalosensors provide a means to detect iron in biological systems that is versatile, economical, sensitive and of a high-throughput nature. They rely on relatively high-affinity iron-binding carriers conjugated to highly fluorescent probes that undergo quenching after metal complexation. Metal specificity is determined by probes containing either an iron-binding moiety of high affinity (type A) or of relatively lower affinity (type B) used in combination with a strong specific iron chelator. Due to the heterogeneous nature of biological systems, the apparent metal-binding affinity and complexation stoichiometry ought to be specifically defined. Fluoresceinated moieties coupled to metal-binding cores detect Fe at sub-micromolar concentrations and even sub-microlitre volumes (i.e. cells). Although an ideal probe should also be specific for a particular oxidation state of iron, in physiological conditions that property might be difficult to attain. Quantification of labile iron in cells has relied on the ability of permeant iron chelators to restore the fluorescence of probes quenched by intracellular Fe. Modern design of probes aims to (a) improve probe targeting to specific cell compartments and (b) create probes that respond to metal binding by signal enhancement.

Sign in / Sign up

Export Citation Format

Share Document