BioMetals (v.30, #6)

Wilson Disease (WD) is a hereditary genetic disorder, which coincides with a dysfunctional copper (Cu) metabolism caused by mutations in ATP7B, a membrane-bound P1B-type ATPase responsible for Cu export from hepatic cells. The N-terminal part (~ 600 residues) of the multi-domain 1400-residue ATP7B constitutes six metal binding domains (MBDs), each of which can bind a copper ion, interact with other ATP7B domains as well as with different proteins. Although the ATP7B’s MBDs have been investigated in vitro and in vivo intensively, it remains unclear how these domains modulate overall structure, dynamics, stability and function of ATP7B. The presence of six MBDs is unique to mammalian ATP7B homologs, and many WD causing missense mutations are found in these domains. Here, we have summarized previously reported in vitro biophysical data on the MBDs of ATP7B and WD point mutations located in these domains. Besides the demonstration of where the research field stands today, this review showcasts the need for further biophysical investigation about the roles of MBDs in ATP7B function. Molecular mechanisms of ATP7B are important not only in the development of new WD treatment but also for other aspects of human physiology where Cu transport plays a role.
Keywords: Wilson disease; ATP7B; Atox1; Metal-binding domains; Cu transport; Disease-causing mutations

Lipophilic gold(I) complexes with 1,3,4-oxadiazol-2-thione or 1,3-thiazolidine-2-thione moieties: synthesis and their cytotoxic and antimicrobial activities by Angelina Maria de Almeida; Bruno Assis de Oliveira; Pedro Pôssa de Castro; Camille Carvalho de Mendonça; Ricardo Andrade Furtado; Heloiza Diniz Nicolella; Vânia Lúcia da Silva; Cláudio Galuppo Diniz; Denise Crispim Tavares; Heveline Silva; Mauro Vieira de Almeida (841-857).
This article has been corrected. One of the author names was given incorrect. Please find in this erratum the correct author name: “Heloiza Diniz Nicolella” that should be regarded as final by the reader.Novel lipophilic gold(I) complexes containing 1,3,4-oxadiazol-2-thione or 1,3-thiazolidine-2-thione derivatives were synthesized and characterized by IR, high resolution mass spectrometry, and 1H, 13C 31P NMR. The cytotoxicity of the compounds was evaluated considering cisplatin and/or auranofin as reference in different tumor cell lines: colon cancer (CT26WT), metastatic skin melanoma (B16F10), breast adenocarcinoma (MCF-7), cervical carcinoma (HeLa), glioblastoma (M059 J). Normal human lung fibroblasts (GM07492-A) and kidney normal cell (BHK-21) were also evaluated. The gold(I) complexes were more active than their respective free ligands and cisplatin. Furthermore, antibacterial activity was evaluated against Gram-positive bacteria Staphylococcus aureus ATCC 25213, Staphylococcus epidermidis ATCC 12228 and Gram-negative bacteria Escherichia coli ATCC 11229 and Pseudomonas aeruginosa ATCC 27853 and expressed as the minimum inhibitory concentration (MIC). The complexes exhibited lower MIC values when compared to the ligands and chloramphenicol against Gram-positive bacteria and Gram-negative bacteria. Escherichia coli was sensitive one to the action of gold(I) complexes.
Keywords: Azole; Gold(I) complex; Lipophilicity; Antitumor; Antibacterial

Correction to: Lipophilic gold(I) complexes with 1,3,4-oxadiazol-2-thione or 1,3-thiazolidine-2-thione moieties: synthesis and their cytotoxic and antimicrobial activities by Angelina Maria de Almeida; Bruno Assis de Oliveira; Pedro Pôssa de Castro; Camille Carvalho de Mendonça; Ricardo Andrade Furtado; Heloiza Diniz Nicolella; Vânia Lúcia da Silva; Cláudio Galuppo Diniz; Denise Crispim Tavares; Heveline Silva; Mauro Vieira de Almeida (859-859).
This article has been corrected. One of the author names was given incorrect. Please find in this erratum the correct author name: “Heloiza Diniz Nicolella” that should be regarded as final by the reader.

TvZNF1 is a C2H2 zinc finger protein of Trichomonas vaginalis by José Luis Villalpando; Rodrigo Arreola; Jonathan Puente-Rivera; Elisa Azuara-Liceaga; Jesús Valdés; Lilia López-Canovas; Alma Villalobos-Osnaya; Maria Elizbeth Alvarez-Sánchez (861-872).
The zinc fingers proteins (ZNF) are the largest family of DNA binding proteins and can act as transcriptional factors in eukaryotes. ZNF are implicated in activation in response to environmental stimulus by biometals such as Zn2+. Many of these proteins have the classical C2H2 zinc finger motifs (C2H2-ZNFm) of approximately 30 amino acids, where a Zn2+ ion is coordinated by two cysteine and two histidine residues. Trichomonas vaginalis is a protozoan parasite than responds to environmental changes including Zn2+. Until now has not been described any ZNF that could be involved in the regulation of genic expression of T. vaginalis. Here, we characterized in silico and experimentally an annoted ZNF (TvZNF1) from T. vaginalis and isolated the gene, tvznf1 encoding it. TvZNF1 have eight C2H2-ZNFm with residues that maybe involved in the structural stability of DNA binding motifs. In this work we confirmed the Zn2+ upregulation expression of tvznf1 gene. Recombinant TvZNF1 was able to bind to specific DNA sequences according to EMSA assay. Additionally, we demonstrated that recombinant TvZNF1 bind to MRE signature in vitro, which strongly suggests its role in transcriptional regulation, similar to the one observed for mammalian MTF-1. This result suggested a conserved mechanism of genic regulation mediated by ZNFs in T. vaginalis.
Keywords: Trichomonas vaginalis ; C2H2 Zinc finger protein; DNA binding protein; TvZNF1

Vanadium(V) complexes with hydrazides and their spectroscopic and biological properties by Sadaf Sultan; Uzma Ashiq; Rifat Ara Jamal; Mohammad Mahroof-Tahir; Zara Shaikh; Bushra Shamshad; Mehreen Lateef; Lubna Iqbal (873-891).
The present study explores the synthesis and inhibitory potential of vanadium(V) complexes of hydrazides (1c12c) against oxidative enzymes including xanthine oxidase and lipoxygenase (LOX). In addition, non-enzymatic radical scavenging activities of these complexes were also determined. On the basis of spectral, elemental and physical data, synthesized vanadium(V) complexes are tentatively assigned to have an octahedral geometry with two hydrazide ligands and two oxo groups forming a negatively charged sphere complex with ammonium as counter ion. This is further verified by the conductivity studies of the complexes. Results show that hydrazide ligands (112) and their respective vanadium(V) complexes (1c12c) posses scavenging and inhibition potential against DPPH and LOX, respectively. However, contrary to that uncoordinated ligands showed no activity against nitric oxide, superoxide and xanthine oxidase whereas their complexes showed varying degree of activity. These studies indicate that geometry of complex, nature and position of substituent groups play a vital role in scavenging and inhibition potential of these compounds.
Keywords: Vanadium(V); Lipoxygenase; Xanthine oxidase; Radical scavenging; Enzyme

Biocidal properties of maltose reduced silver nanoparticles against American foulbrood diseases pathogens by Mustafa Çulha; Şaban Kalay; Elif Sevim; Müberra Pinarbaş; Yıldız Baş; Rahşan Akpinar; Şengül Alpay Karaoğlu (893-902).
Bee disease caused by spore-forming Paenibacillus larvae and Paenibacillus alvei is a serious problem for honey production. Thus, there is an ongoing effort to find an effective agent that shows broad biocidal activity with minimal environmental hazard. In this study, the biocidal effect of maltose reduced silver nanoparticles (AgNPs) is evaluated against American foulbrood and European foulbrood pathogens. The results demonstrate that the maltose reduced AgNPs are excellent short and long-term biocides against P. larvae isolates. The long-term effect suggests that the Ag+ ions are released from the AgNPs with increasing time in a controlled manner.
Keywords: Silver nanoparticles; Honeybee pathogens; American foulbrood; European foulbrood; AgNPs

Rhodium (II) complex with 2-benzoylpyridine (Rh(L)2Cl2) is a new, synthetic, active metal-complex, which is produced by the reaction of 2-benzoylpyridine (L) with rhodium chloride hydrate (RhCl3·nH2O). The crystal structure was determined by X-ray diffraction which is mono-nuclear. In order to explore the biological properties of the novel complex, a series of studies were performed. The results showed that Rh(L)2Cl2 had the anti-tumor activity in HepG2 and other cell lines and has been shown to induce G1 cell cycle arrest and apoptosis in HepG2 cells. The anti-cancer effect of Rh(L)2Cl2 is regulated by increased expression of caspase-3 and PARP via the mitochondrial and the death receptor pathways. Bcl-2 family proteins might play an important role in the Rh(L)2Cl2-induced changes in these two pathways. Further studies indicated that Rh(L)2Cl2 increased the level of reactive oxygen species (ROS), but that Rh(L)2Cl2-induced apoptosis was ROS-independent. In conclusion, Rh(L)2Cl2 is a potential new anti-tumor drug, which induces HepG2 cell death via the mitochondrial and death receptor pathways and has no obvious toxicity to normal liver cell.
Keywords: Rhodium (II) complex; G1 phase; Apoptosis; Mitochondrial pathway; Death receptor

In plants, metal transporters are responsible for metal uptake, translocation and homeostasis. These metals include essential nutrients such as zinc (Zn) and manganese (Mn) or non-essential metals like cadmium (Cd) and lead (Pb). Although a few metal transporters have been well characterized in model plants, little is known about their functionality in rapeseed (Brassica napus). In the study, 22 NRAMP transporter genes from B. napus genome were identified and annotated using bioinformatics and high-throughput RNA-sequencing (RNA-seq). Based on the sequence identity, these NRAMP transporters can be classified into 6 subfamilies. RNA-seq analysis revealed that 19 NRAMP transporters were detected and some of the genes were well confirmed by qRT-PCR. Ten NRAMP transporters (45.5%, 10/22) were found to be differentially expressed (> 2 fold change, p < 0.05) under Cd exposure. As an example, we specified expression of BnNRAMP1b under Cd exposure. BnNRAMP1b is a constitutive gene expressing throughout all development stages including seedlings, vegetative tissue, flowers and siliques. Expression of BnNRAMP1b can be strongly induced in seedlings exposed to 80, 160 and 240 μM Cd. To define whether BnNRAMP1b was specific for Cd transport, a yeast (wild-type, BY4741) system with its mutants (ycf1, zrc1, and smf1) defective in transport activity of Cd, Zn and Mn, respectively were tested. Compared to empty vectors (pYES2), cells carrying BnNRAMP1b can rescue the transport functions. As a consequence, excess Cd, Zn and Mn were taken in the cells, which led to metal toxicity, suggesting that BnNRAMP1b is responsible for transport of these metals in B. napus. Using our previously created degradome datasets, we found that BnNRAMP1b could be cleaved by miR167, suggesting that BnNRAMP1b is a target of miR167 in B. napus. The contrasting expression pattern of BnNRAMP1b and miR167 under Cd stress supported the post-transcriptional regulation of BnNRAMP1b by miR167.
Keywords: Brassica napus ; NRAMP transporters; Cadmium; Transcriptome

The apoptotic, cytotoxic and genotoxic effect of novel binuclear boron-fluoride complex on endometrial cancer by Yasin Tülüce; Pawan Tareq Ahmed Lak; İsmail Koyuncu; Ahmet Kılıç; Mustafa Durgun; Halil Özkol (933-944).
Endometrial cancer (EC) is one of the most common types of gynecologic cancer of the female genital tract; it considered being the fourth leading death factor among other types of cancer. Therefore, developing new anti-cancer agents are crucial for cancer treatment. Based on the potential of Schiff based complexes for the induction of apoptosis, Schiff base compounds, and their metal complexes displayed excellent anticancer properties. In this current study, antiproliferative activity of [L(BF2)2] as a novel binuclear boron-fluoride complex was examined to preliminary research in eight different cell lines, HELA, DU-145, PC3, DLD-1, ECC-1, PNT1-A, HT-29, and MCF-7, it was found to have a potent, suppressive effect on human endometrial adenocarcinoma cell line ECC-1. Based on this data, later investigated its apoptotic, cytotoxic, and genotoxic properties on human endometrial adenocarcinoma cell line ECC-1 in different concentrations. Apoptotic and cytotoxic tests such as single cell gel electrophoresis assay (comet assay), DNA fragmentation laddering, acridine orange test for DNA damage, and ELISA for apoptotic measurement was performed. We also gauged the oxidative status by evaluating total antioxidant status (TAS) and total oxidant status (TOS). Oxidative stress index (OSI) was calculated too. As a result [L(BF2)2] has been found to have a marvelous effect on ECC-1 cells, especially in damaging their DNA and cause a series of reactions lead to apoptosis. Taken together, it suggests that the [L(BF2)2] complex can induce the apoptotic pathway of endometrial cancer cells and is a possible candidate for future cancer treatment studies.
Keywords: Apoptosis; Cytotoxicity; Endometrial cancer; DNA damage; Chemotherapy

Iron uptake and storage in the HAB dinoflagellate Lingulodinium polyedrum by Kyoko Yarimizu; Ricardo Cruz-López; Hendrik Auerbach; Larissa Heimann; Volker Schünemann; Carl J. Carrano (945-953).
The iron uptake and storage systems of terrestrial/higher plants are now reasonably well understood with two basic strategies being distinguished: Strategy I involves the induction of an Fe(III)-chelate reductase (ferrireductase) along with Fe(II) or Fe(III) transporter proteins while strategy II plants have evolved sophisticated systems based on high-affinity, iron specific, binding compounds called phytosiderophores. In contrast, there is little knowledge about the corresponding systems in marine, plant-like lineages. Herein we report a study of the iron uptake and storage mechanisms in the harmful algal bloom dinoflagellate Lingulodinium polyedrum. L. polyedrum is an armored dinoflagellate with a mixotrophic lifestyle and one of the most common bloom species on Southern California coast widely noted for its bioluminescent properties and as a producer of yessotoxins. Short term radio-iron uptake studies indicate that iron is taken up by L. polyedrum in a time dependent manner consistent with an active transport process. Based on inhibitor and other studies it appears that a reductive–oxidative pathway such as that found in yeast and the green alga Chlamydomonas reinhardtii is likely. Of the various iron sources tested vibrioferrin, a photoactive and relatively weak siderophore produced by potentially mutualistic Marinobacter bacterial species, was the most efficient. Other more stable and non-photoactive siderophores such as ferrioxamine E were ineffective. Several pieces of data including long term exposure to 57Fe using Mössbauer spectroscopy suggest that L. polyedrum does not possess an iron storage system but rather presumably relies on an efficient iron uptake system, perhaps mediated by mutualistic interactions with bacteria.
Keywords: HAB; dinoflagellates; iron; uptake; storage; siderophores

Life and death of Trypanosoma cruzi in presence of metals by Laís Pessanha de Carvalho; Edésio José Tenório de Melo (955-974).
Trypanosoma cruzi has many molecules that need metallic elements to work, allowing cell invasion and the establishment of infection, causing Chagas disease. Nonetheless, knowledge regarding how the parasites address metals and maintain homeostasis is lacking. To study this relationship, zinc, cadmium and mercury were chosen. Epimastigote, trypomastigote and intracellular forms of T. cruzi were incubated with these metals for different times and at different concentrations. In general, epimastigotes were the most sensitive and trypomastigotes the most resistant to metals. ZnCl2 induced low toxic effects to all parasite forms. Although the parasites were very sensitive to the toxic effects of CdCl2 and HgCl2, pretreatment with ZnCl2 decreased the death rate. The trypomastigotes pretreated with CdCl2 were unable to infect the host cells, and the treated intracellular forms were damaged after 2 h of incubation, when the toxic effects were poorly reverted. New insights on metal toxicity mechanisms are provided, helping to understand how metallic ions influence the parasite’s biochemical and physiological processes.
Keywords: Cadmium; Essential metals; Mercury; Non-essential metals; Trypanosoma cruzi and zinc

Two mTOR inhibitors, rapamycin and Torin 1, differentially regulate iron-induced generation of mitochondrial ROS by Hui Huang; Jun Chen; Huiru Lu; Mengxue Zhou; Zhifang Chai; Yi Hu (975-980).
It is generally believed that gene-environment interaction may contribute to neurodegeneration. Of particular note is that iron overload may be one of the risk factors for neurodegeneration. However, the mechanisms underlying iron-associated neurotoxicity are not fully understood. Here we explored the effects of mechanistic target of rapamycin (mTOR) inhibition in iron-stressed human neuroblastoma cells. Two mTOR inhibitors, rapamycin and Torin 1, had similar effects in cells exposed to a relatively low concentration of iron. At a higher concentration of iron, Torin 1, instead of rapamycin, could further aggravate iron-induced cytotoxicity, and mitochondrial ROS levels were significantly higher in Torin 1-treated cells. These results suggest that mTOR inhibition may not be able to alleviate iron-induced neurotoxicity.
Keywords: mTOR; Rapamycin; Torin 1; ROS