Desenvolvimento de compostos de coordenação para aplicação foliar e elucidação do mecanismo de absorção / Development of coordination compounds for foliar application and elucidation of the absorption mechanism

O objetivo geral desse trabalho foi desenvolver compostos de coordenação com os metais cobre, manganês, zinco, cobalto, níquel e magnésio com os aminoácidos L- ácido aspártico e glutâmico para aplicação como fertilizantes foliares e elucidação de seus prováveis mecanismos de absorção pela planta. Como plano de trabalho, pretendeu-se produzir alguns complexos metálicos com agentes complexantes que confiram características específicas: alta estabilidade termodinâmica e cinética quando comparado a quelatos usados comercialmente dos mesmos metais; alta solubilidade; compatibilidade com herbicidas e fungicidas e alta estabilidade frente a variações de pH. Os compostos foram caracterizados no estado sólido e/ou em solução aquosa, através de técnicas disponíveis em nosso laboratório, na Central Analítica do IQ-USP e/ou nos laboratórios da ICL América do Sul Ind. e Com. SA. Com o desenvolvimento dos compostos de coordenação, foram avaliados alguns parâmetros considerados imprescindíveis para garantia da qualidade do produto gerado, que foram então comparados aos de quelatos de EDTA (ácido etilenodiaminotetraacético) comercializados atualmente e que demonstraram vantagens. Para avaliar a eficiência dos produtos gerados foi realizada aplicação foliar em ao menos uma cultura e verificado o teor de cada nutriente após período de absorção e resposta produtiva, evidenciando e determinando o mecanismo de absorção realizado pela planta. Como resultado, desenvolveu-se uma série de produtos com alta tecnologia agregada que trouxeram benefícios nutricionais, sustentando uma nutrição de qualidade além de serem ecologicamente favoráveis (eco-friendly portfolio)

This project aims the development of copper, manganese, zinc, cobalt, nickel and iron metal complexes with L-amino acids aspartic and glutamic acids for application as foliar fertilizers and elucidation of the probable incorporation/absorption mechanism by plants. As a work plan, it was intended to produce these metal complexes with complexing agents that provide specific characteristics: high thermodynamic and kinetic stabilities when compared to the corresponding EDTA chelates; high solubility; compatibility with herbicides and fungicides and high stability against pH variations. With the development of such coordination compounds, some parameters considered indispensable to quality assurance were then evaluated, in comparison to that of currently available commercial EDTA chelates. To evaluate the performance of the obtained compounds, two foliar applications in the same crop were carried out. Further, the content of each nutrient after the production period and the productive capacity were evaluated, aiming to elucidate the absorption mechanism of the plant. As a result, elaborated products with high added technology were obtained, capable of ameliorating the nutritional benefits, that can support an eco-friendly portfolio

CXCR4 PET/MRI for follow-up of gastric mucosa-associated lymphoid tissue lymphoma after first-line Helicobacter pylori eradication.

Posttreatment evaluation of gastric mucosa-associated lymphoid tissue (MALT) lymphoma currently relies on esophagogastroduodenoscopy with histological assessment of biopsies. Overexpression of the G protein-coupled C-X-C chemokine receptor type 4 (CXCR4) has been previously observed in MALT lymphoma. The aim of this prospective study was to evaluate positron emission tomography (PET) with the novel CXCR4 tracer [68Ga]Pentixafor as a potential alternative to follow up biopsies for assessment of residual disease (noncomplete remission [CR]) after first-line Helicobacter pylori eradication. Forty-six post-H pylori eradication [68Ga]Pentixafor-PET/magnetic resonance imaging (MRI) examinations of 26 gastric MALT lymphoma patients, and 20 [68Ga]Pentixafor-PET/MRI examinations of 20 control group patients without lymphoma, were analyzed. In the MALT lymphoma group, time-matched gastric biopsies were used as reference standard and showed CR in 6 cases. Pooled examination-based accuracy, sensitivity, specificity, and positive and negative predictive values of [68Ga]Pentixafor-PET for detection of residual gastric MALT lymphoma at follow-up were 97.0%, 95.0%, 100.0%, 100.0%, and 92.9%, respectively. Maximum and mean PET standardized uptake values showed moderate correlation with immunohistochemistry-based CXCR4+ cell counts, with correlation coefficients of r = 0.51 and r = 0.52 (P = .008 and P = .006). In summary, CXCR4 imaging with [68Ga]Pentixafor-PET may represent a promising test for assessment of residual gastric MALT lymphomas after H pylori eradication.

Electrospray-Induced Mass Spectrometry Is Not Suitable for Determination of Peptidic Cu(II) Complexes.

The toolset of mass spectrometry (MS) is still expanding, and the number of metal ion complexes researched this way is growing. The Cu(II) ion forms particularly strong peptide complexes of biological interest which are frequent objects of MS studies, but quantitative aspects of some reported results are at odds with those of experiments performed in solution. Cu(II) complexes are usually characterized by fast ligand exchange rates, despite their high affinity, and we speculated that such kinetic lability could be responsible for the observed discrepancies. In order to resolve this issue, we selected peptides belonging to the ATCUN family characterized with high and thoroughly determined Cu(II) binding constants and re-estimated them using two ESI-MS techniques: standard conditions in combination with serial dilution experiments and very mild conditions for competition experiments. The sample acidification, which accompanies the electrospray formation, was simulated with the pH-jump stopped-flow technique. Our results indicate that ESI-MS should not be used for quantitative studies of Cu(II)-peptide complexes because the electrospray formation process compromises the entropic contribution to the complex stability, yielding underestimations of complex stability constants.

Quantum chemical calculation studies toward microscopic understanding of retention mechanism of Cs radioisotopes and other alkali metals in lichens.

We evaluate stability of cesium (Cs) and other alkali-metal cation complexes of lichen metabolites in both gas and aqueous phases to discuss why lichens can retain radioactive Cs in the thalli over several years. We focus on oxalic acid, (+)-usnic acid, atranorin, lecanoric acid, and protocetraric acid, which are common metabolite substances in various lichens including, e.g., Flavoparmelia caperata and Parmotrema tinctorum retaining Cs in Fukushima, Japan. By performing quantum chemical calculations, their gas-phase complexation energies and aqueous-solution complexation free energies with alkali-metal cations are computed for their neutral and deprotonated cases. Consequently, all the molecules are found to energetically favor cation complexations and the preference order is Li[Formula: see text]Na[Formula: see text]K[Formula: see text]Rb[Formula: see text]Cs[Formula: see text] for all conditions, indicating no specific Cs selectivity but strong binding with all alkali cations. Comparing complexation stabilities among these metabolites, lecanoric and protocetraric acids seen in medullary layer are found to keep higher affinity in their neutral case, while (+)-usnic acid and atranorin in upper cortex exhibit rather strong affinity only in deprotonated cases through forming stable six atoms' ring containing alkali cation chelated by two oxygens. These results suggest that the medullary layer can catch all alkali cations in a wide pH range around the physiological one, while the upper cortex can effectively block penetration of metal ions when the metal stress grows. Such insights highlight a physiological role of metabolites like blocking of metal-cation migrations into intracellular tissues, and explain long-term retention of alkali cations including Cs in lichens containing enough such metabolites to bind them.

Direct distinction of ibuprofen and flurbiprofen enantiomers by ion mobility mass spectrometry of their ternary complexes with metal cations and cyclodextrins in the gas phase.

Enantiomeric drugs are widely used and play important roles in pharmaceuticals. Ion mobility spectrometry coupled with mass spectrometry technology provides a unique method for distinguishing the enantiomeric drugs, enantiomeric identification, and quantitation in the gas phase. In this study, enantiomeric molecules of ibuprofen and flurbiprofen were clearly recognized by forming host-guest complex ions using trapped ion mobility time-of-flight mass spectrometry. Ternary complex ions can be produced easily by electrospray ionization of the mixed solutions of ibuprofen, cyclodextrins, and CaCl2 , LiCl, or NaCl, as well as flurbiprofen, cyclodextrins, and CaCl2 . The relative contents of different chiral ibuprofens in a mixed solution were also quantitatively measured. This new method is a simple, effective, and a convenient enantioselective analysis method.

Phosphonate Chelators for Medicinal Metal Ions.

A family of phosphonate-bearing chelators was synthesized to study their potential in metal-based (radio)pharmaceuticals. Three ligands (H6phospa, H6dipedpa, H6eppy; structures illustrated in manuscript) were fully characterized, including X-ray crystallographic structures of H6phospa and H6dipedpa. NMR spectroscopy techniques were used to confirm the complexation of each ligand with selected trivalent metal ions. These methods were particularly useful in discerning structural information for Sc3+ and La3+ complexes. Solution studies were conducted to evaluate the complex stability of 15 metal complexes. As a general trend, H6phospa was noted to form the most stable complexes, and H6eppy associated with the least stable complexes. Moreover, In3+ complexes were determined to be the most stable, and complexes with La3+ were the least stable, across all metals. Density functional theory (DFT) was employed to calculate structures of H6phospa and H6dipedpa complexes with La3+ and Sc3+. A comparison of experimental 1H NMR spectra with calculated 1H NMR spectra using DFT-optimized structures was used as a method of structure validation. It was noted that theoretical NMR spectra were very sensitive to a number of variables, such as ligand configuration, protonation state, and the number/orientation of explicit water molecules. In general, the inclusion of an explicit second shell of water molecules qualitatively improved the agreement between theoretical and experimental NMR spectra versus a polarizable continuum solvent model alone. Formation constants were also calculated from DFT results using potential-energy optimized structures. Strong dependence of molecular free energies on explicit water molecule number, water molecule configuration, and protonation state was observed, highlighting the need for dynamic data in accurate first-principles calculations of metal-ligand stability constants.

Reversible Chemosensor for Bioimaging and Biosensing of Zn(II) and hpH in Cells, Larval Zebrafish, and Plants with Dual-Channel Fluorescence Signals.

Zinc/Zn(II) is an essential trace element for humans and acts as an important substance that maintains the normal growth, development, and metabolism of the body. Excess or deficient Zn(II) can cause abnormal metabolism in the human body, leading to a series of diseases. Moreover, biosystems have complex homeostasis systems, especially harsh pH (OH-) environments. Thus, investigating the variation in the levels of Zn(II) and OH- is extremely important in clinical, medical, and environmental testing. Nevertheless, the lack of practical and convenient fluorescence imaging tools limits the tracing of Zn(II) and OH- in biosystems. In this work, a well-designed dual-channel fluorescent signal response chemosensor (DACH-fhba) was assembled for selective sensing of Zn(II) and OH- in the biosystem using a fluorescence turn-on strategy. On encountering Zn(II), the chemosensor emitted a blue fluorescence signal (455 nm). Meanwhile, the bright green fluorescence signal (530 nm) increased with OH- addition simultaneously. With the blue/green dual fluorescence response of DACH-fhba, the sensor exhibited high stability and reversibility. Notably, the bioimaging revealed that DACH-fhba successfully tracked Zn(II) and OH- in live cells, larval zebrafish, and plants. Further results implied that DACH-fhba can be used to achieve visual detection of Zn(II) and OH- in organisms. Altogether, this work is conducive to the monitoring of Zn(II) and OH- in organisms and promotes the understanding of the function of Zn(II) and OH- in biosystems.

Unexpected reversible and controllable nuclear uptake and efflux of the DNA "light-switching" Ru(ii)-polypyridyl complex in living cells via ion-pairing with chlorophenolate counter-anions.

An in-depth understanding of the mechanisms of cellular uptake and efflux would facilitate the design of metal complexes with not only better functionality and targeted theranostic efficiency, but also with controlled toxicity. Here we find, unexpectedly, that the DNA "light-switching" Ru(ii)-polypyridyl complex [Ru(phen)2(dppz)]2+ already delivered to the nucleus via ion-pairing with chlorophenolate counter-anions can gradually efflux to the cytoplasm when the cells were washed and incubated with fresh culture-medium. Interestingly, [Ru(phen)2(dppz)]2+ effluxed to the cytoplasm can be redirected back to the nucleus when the chlorophenolate counter-anions were added again. The efflux of nuclear [Ru(phen)2(dppz)]2+ was found to be mediated mainly via ATP-binding cassette (ABC) transporter proteins. Analogous reversible, but enantio-selective nuclear uptake and efflux were observed with the two pure chiral forms of [Ru(phen)2(dppz)]Cl2. This represents the first report of reversible and controllable nuclear uptake and efflux of a DNA "light-switching" Ru(ii)-complex in living-cells via ion-pairing, which should provide novel insights for future research on using ion-pairing as an effective approach to control the cellular uptake and redistribution of other potential theranostic metal complexes.

Fulvic acids from Amazonian anthropogenic soils: Insight into the molecular composition and copper binding properties using fluorescence techniques.

Fulvic acids (FA) are one of the components of humic substances and play an important role in the interaction with metallic species and, consequently, the bioavailability, distribution and toxicity of metals. However, only a few studies have investigated these FA properties in specific environment, such as anthropogenic soils. Therefore, knowledge about FA molecular composition as well as the FA-metal interaction is essential to predict their behavior in the soil. For this reason, the aim of this study was to investigate the molecular composition of FA extracted from two sites in an anthropogenic soil (Terra Mulata), from the Amazon region, as well as their interactions with Cu(II) ions as a model. Results from 13C NMR, infrared and elemental analysis showed that these FA are composed mostly by alkyl structures and oxygen-functional groups, e.g., hydroxyl, carbonyl and carboxyl. The interaction with Cu(II) ions was evaluated by fluorescence quenching, in which the FA showed both high quantity of complexing sites per gram of carbon and good affinity to interact with the metal when compared with other soil FA. The results showed that the complexation capacity was highly correlated by the content of functional groups, while the binding affinity was largely influenced by structural factors. In addition, through the lifetime decay given by time-resolved fluorescence, it was concluded that static quenching took place in FA and Cu(II) interaction with the formation of a non-fluorescent ground-state complex. Therefore, this fraction of soil organic matter will fully participate in complexation reactions, thereby influencing the mobility and bioavailability of metal in soils. Hence, the importance of the study, and the role of FA in the environment, can be seen especially in the Amazon, which is one of the most important biomes in the world.

The development of two fluorescent chemosensors for the selective detection of Zn2+ and Al3+ ions in a quinoline platform by tuning the substituents in the receptor part: elucidation of the structures of the metal-bound chemosensors and biological studies.

Here, two 8-aminoquinoline-based chemosensors, namely, HL1 and HL2 (HL1 = 2,4-dibromo-6-((quinolin-8-ylimino)methyl)phenol and HL2 = 4-nitro-2-((quinolin-8-ylimino)methyl)phenol) were synthesized by simply changing the substituents in the ligand framework under ambient conditions. They were thoroughly characterized using different spectroscopic techniques, including ESI-mass spectrometry and elemental analysis. HL1 selectively sensed Zn2+ ions, whereas HL2 detected Al3+ ions. The metal-bound chemosensors (complexes 1 and 2) were also investigated using different techniques including X-ray crystallography. The binding stoichiometry of the probes with the respective ions was confirmed to be 2 : 1 by Job's plot analysis and X-ray crystallography. The limit of detection (LOD) values for both chemosensors towards the respective metal ions were in the order of ∼10-7 M, which clearly indicates that these probes have significant potential for biological applications. The capability of our synthesized chemosensors to detect intracellular Zn2+ and Al3+ ions in the triple negative human breast cancer cell line MDA-MB-468 was evaluated with the aid of fluorescence imaging. Mechanistic insights into the anticancer activity of complexes 1 and 2 were also demonstrated in this study. To the best of our knowledge, this is the first time that this type of biological and sensing activity for 8-aminoquinoline-based complexes has been demonstrated in a single platform.

Targeted Luminescent Europium Peptide Conjugates: Comparative Analysis Using Maleimide and para-Nitropyridyl Linkages for Organelle Staining.

The syntheses and photophysical behavior of nine strongly luminescent nonadentate Eu(III) complexes are reported. Each complex is based on N-functionalized 1,4,7-triazacyclononane, and linkage to other groups or targeting vectors can occur either via amide bond formation to a coordinated pyridine p-aminopropyl group or via a nucleophilic substitution reaction involving thiol attack on a metal coordinated p-nitropyridyl moiety. Evidence is presented in favor of the latter conjugation strategy, as parallel work with maleimide conjugates was complicated or compromised by the propensity to undergo post-conjugation thiol exchange or succinimide ring hydrolysis reactions. Confocal microscopy and spectral imaging studies revealed that the peptide conjugate of AcCFFKDEL was found to localize selectively in the endoplasmic reticulum of mouse fibroblast cells, whereas the related maleimide conjugate was only observed in cellular lysosomes.

Metal-Ligand Coordination Nanomaterials for Biomedical Imaging.

Over the past two decades, amorphous nanoscale coordination polymers (NCPs) and crystalline nanoscale metal-organic frameworks (NMOFs) have emerged as attractive nanomaterials in biomedical applications, especially in drug delivery, biomedical imaging, and biosensing. The biodegradability, tunable composition, and feasible functionality of NCPs/NMOFs make them excellent contrast agents or nanocarriers for biomedical imaging, including magnetic resonance (MR) imaging, positron emission tomography (PET), computed tomography (CT), optical imaging, and photoacoustic (PA) imaging. In this Topical Review, we will summarize the recent advances of NCPs/NMOFs in biomedical imaging with emphasis on research over the past three years. A variety of imaging technologies based on NCPs/NMOFs will be discussed, followed by the introduction of the application of NCPs/NMOFs in multimodal imaging where optical/MR imaging is highlighted. In the final part, we will make concluding remarks and point out the challenges and prospects for the further development in this area of research.

Determination of melamine and melamine-Cu(II) complexes in milk using a DNA-Ag hydrocolloid as the sensor.

Simple and sensitive methods are required for the detection of melamine since melamine is harmful to human health. To detect the content of melamine and metal-melamine species in milk products, a new luminescent DNA silver hydrocolloid (AgNC53) was synthesized using a modified C3A-rich aptamer as the template. The emission of AgNC53 at 617 nm is sensitive to both melamine-Cu(II) and melamine, while almost no response to the free Cu(II) ion was detected. Moreover, AgNC53 is used to detect precisely the content of melamine in milk with a detection limit as low as 2.7 × 10-8 M. Thus, the AgNC53-based fluorescence method is a "label-free" fluorescence technology that can be used for the determination of melamine or the melamine-Cu(II) complex in milk products.

Intramolecular and Metal-to-Molecule Charge Transfer Electronic Resonances in the Surface-Enhanced Raman Scattering of 1,4-Bis((E)-2-(pyridin-4-yl)vinyl)naphthalene.

Electrochemical surface-enhanced Raman scattering (SERS) of the cruciform system 1,4-bis((E)-2-(pyridin-4-yl)vinyl)naphthalene (bpyvn) was recorded on nanostructured silver surfaces at different electrode potentials by using excitation laser lines of 785 and 514.5 nm. SERS relative intensities were analyzed on the basis of the resonance Raman vibronic theory with the help of DFT calculations. The comparison between the experimental and the computed resonance Raman spectra calculated for the first five electronic states of the Ag2-bpyvn surface complex model points out that the selective enhancement of the SERS band recorded at about 1600 cm-1, under 785 nm excitation, is due to a resonant Raman process involving a photoexcited metal-to-molecule charge transfer state of the complex, while the enhancement of the 1570 cm-1 band using 514.5 nm excitation is due to an intramolecular π→π* electronic transition localized in the naphthalenyl framework, resulting in a case of surface-enhanced resonance Raman spectrum (SERRS). Thus, the enhancement of the SERS bands of bpyvn is controlled by a general chemical enhancement mechanism in which different resonance processes of the overall electronic structure of the metal-molecule system are involved.

Magnetism-reinforced in-tube solid phase microextraction for the online determination of trace heavy metal ions in complex samples.

For the first time, a convenient, online couplable, sensitive and environmentally friendly sample pretreatment method, namely, magnetism-reinforced in-tube solid phase microextraction (MR/IT-SPME) was proposed to effectively enrich heavy metal ions (HMIs). Monolithic capillary microextraction column embedded modified Fe3O4 magnetic nanoparticles (MCEN) was conveniently synthesized and employed as the microextraction column of MR/IT-SPME. Subsequently, the MCEN was put into a magnetic coil which was utilized to exert variable magnetic field during extraction procedure. Three HMIs, including Cu(II), Co(II) and Hg(II), were selected as studied ions and reacted with chelating agent sodium diethyldithiocarbamatetrihydrate to form metallic coordination compounds. The complexes were infused to the MCEN to perform the MR/IT-SPME extraction and then online determined by high-performance liquid chromatography equipped with diode array detection (HPLC-DAD). A series of key parameters affecting the extraction performance were investigated in detail. Results revealed that the exertion of magnetic field in adsorption and desorption steps favored the adsorption and release of the coordination compounds, with the extraction efficiencies enhanced from 47-65% to 67-89%. Finally, the developed online MR/IT-SPME-HPLC-DAD approach was successfully applied to determine studied HMIs in environmental water and seafood samples. The confirmatory experiments further evidenced the reliability and feasibility of the introduced approach for the analysis of trace HMIs in complex samples.

Accurate quantification of metal-glycinates-sulphate complexes and free metals in feed by capillary electrophoresis inductively coupled plasma mass spectrometry.

Traceability of metal-glycinate-sulphate complexes (Metal-GLY) in feed requires specific analysis to differentiate complexes from inorganic forms. A previously described method focused on the quantification of Metal-GLY at one single concentration but not on the quantification of free metal ion forms. The objective of this work was to extend the method to quantify both Metal-GLY and free metal ion forms of various metals at low inclusion levels. A 50/50 w/w mix of corn flour and soybean meal was used as feed. Copper-glycinate(Cu-GLY), Manganese-glycinate (Mn-GLY) and Zinc-glycinate (Zn-GLY) complexes (provided by Pancosma SA) were used for in-feed inclusions. The feed metal background concentrations and species repartitions were assessed. Cu-GLY was spiked on feed at levels matching 5, 15 and 45 mg/kg, corresponding to metal concentrations of 1.2, 3.6 and 10.8 mg/kg. Mn-GLY and Zn-GLY were spiked at 15, 45 and 100 mg/kg, corresponding to 3.3, 9.9, 22 mg/kg Mn and 3.9, 11.7, 26mg/kg Zn, respectively. The water soluble fraction of un-supplemented feed contained 0.06 mg/kg Cu, 0.05 mg/kg Mn and 0.12 mg/kg Zn, with 69.5% of Cu, 33.2% of Mn and 24.3% of Zn being present under free metal ions but 30.4% of Cu being present under Cu-GLY, 66.82% of Mn and 75.7% of Zn being present under Mn-GLY and Zn-GLY, respectively. The supplemented feeds at the 3 tested doses, from the lowest to the highest inclusion levels, contained in total respectively: 1.1, 3.05 and 9.06 mg/kg Cu; 2.99, 8.9 and 18.2 mg/kg Mn; 3.72, 10.9 and 23.4 mg/kg Zn. The M-GLY species recovered by analysis within the different supplemented feeds ranged from 76.26 to 89.32% for Cu-GLY, form 94.5 to 98.51% for Mn-GLY and from 76.05 to 98.96% for Zn-GLY. These results showed that CE-ICP-MS technique can be used to quantify low doses and to measure metal-species repartition between Metal-GLY and free metal ions, when included in feeds. For the first time, this study highlighted that the raw materials used contain Metal-GLY compounds. This raises the question of the occurrence of these compounds within the different raw materials used in feed production that could dramatically affect the way to supplement minerals in animal feed.

Luminescent anticancer ruthenium(ii)-p-cymene complexes of extended imidazophenanthroline ligands: synthesis, structure, reactivity, biomolecular interactions and live cell imaging.

Of late, cancer has become a terrible disease affecting people throughout the world. Keeping this in mind, we tried to design drugs that are more lipophilic, target-specific, water-soluble, cytoselective and fluorescent. In this regard, we reported novel ruthenium(ii)-p-cymene imidazophenanthroline scaffolds as effective DNA targeting agents. The planarity of imidazophenanthroline ligands caused the Ru(ii) complex to be a good intercalator. An extended π-electronic conjugation was introduced in the imidazophenanthroline moieties through the Suzuki and Sonogashira coupling reactions. Here, we synthesized nine Ru(ii) complexes (16a-b, 17a-d, and 19a-c). Among these, [(η6-p-cymene)RuCl(K2-N,N-2-(4'-methyl-[1,1'-BIphenyl]-4-yl)-1H-imidazo[4,5-f][1,10]phenanthroline)]·PF6 (16b) exhibited the best potency and selectivity with excellent cellular uptake; [(η6-p-cymene)RuCl(K2-N,N-2-(4-(phenylethynyl)phenyl)-1H-imidazo[4,5-f][1,10]phenanthroline)]·PF6 (17a) acted as a cytoselective probe for live cell imaging.

Isolated Saccharomyces cerevisiae vacuoles contain low-molecular-mass transition-metal polyphosphate complexes.

Vacuoles play major roles in the trafficking, storage, and homeostasis of metal ions in fungi and plants. In this study, 29 batches of vacuoles were isolated from Saccharomyces cerevisiae. Flow-through solutions (FTS) obtained by passing vacuolar extracts through a 10 kDa cut-off membrane were characterized for metal content using an anaerobic liquid chromatography system interfaced to an online ICP-MS. Nearly all iron, zinc, and manganese ions in these solutions were present as low-molecular-mass (LMM) complexes. Metal-detected peaks with masses between 500-1700 Da dominated; phosphorus-detected peaks generally comigrated. The distribution of metal:polyphosphate complexes was dominated by particular chain-lengths rather than a broad binomial distribution. Similarly treated synthetic FeIII polyphosphate complexes showed similar peaks. Treatment with a phosphatase disrupted the LMM metal-bound species in vacuolar FTSs. These results indicated metal:polyphosphate complexes 6-20 phosphate units in length and coordinated by 1-3 metals on average per chain. The speciation of iron in FTSs from iron-deficient cells was qualitatively similar, but intensities were lower. Under healthy conditions, nearly all copper ions in vacuolar FTSs were present as 1-2 species with masses between 4800-7800 Da. The absence of these high-mass peaks in vacuolar FTS from cup1Δ cells suggests that they were due to metallothionein, Cup1. Disrupting copper homeostasis increased the amount of LMM copper:polyphosphate complexes in vacuoles (masses between 1500-1700 Da). Potentially dangerous LMM copper species in the cytosol of metallothionein-deficient cells may traffic into vacuoles for sequestration and detoxification.

A pyrazole-containing hydrazone for fluorescent imaging of Al3+ in lysosomes and its resultant Al3+ complex as a sensor for F.

A fluorescence-enhanced and lysosome-targeted Al3+ probe (1) based on a pyrazole-containing hydrazone was developed in this work. The fluorescent probe 1 displays an OFF-ON fluorescence response to Al3+ in the lysosome pH environment. In addition, the resultant 1-Al3+ complex could act as an ON-OFF fluorescence sensor for F-. Fluorescence imaging shows that 1 is suitable for visualization of Al3+ in lysosomes of HeLa cells.

Single cell analysis for elucidating cellular uptake and transport of cobalt curcumin complex with detection by time-resolved ICPMS.

It is of great importance to elucidate the fate of drugs, e.g., their cellular uptake, transport and metabolism/excretion at single cell level. In the present work, cellular uptake and excretion of curcumin in HepG2 and MCF-7 cells were investigated by measuring 59Co in a curcumin cobalt complex ([Co(tpa)(cur)](ClO4)2) with inductively coupled plasma mass spectrometry (ICPMS). The uptake and distribution pattern of the metal drug complex in single cells were thoroughly studied, demonstrating extremely large discrepancy of uptake behavior among individual cells. The complex concentration-dependent uptake and excretion behavior is observed for both HepG2 and MCF-7 cells. The uptake of ([Co(tpa)(cur)](ClO4)2) by HepG2 cells is firstly increased with the concentration of the complex followed by level-off at certain level. On the other hand, however, the uptake by MCF-7 cells increases exponentially with the complex concentration within a same concentration range. The present study provides important information on the transport process of the metal drug complex at single cell level, it may be promising for further applications in the elucidation of metal drug effectiveness in vivo.