Effect of aluminum chloride on mitogenesis,mitosis, and cell cycle in human short-term whole blood cultures: Lower concentrations enhance mitosis

Aluminum, the third most common element in the earth's crust (second to oxygen and silicon) and recently suspected by some investigators to be implicated in Alzheimer disease etiology, has been studied in relation to its effect on mitogenesis, mitosis, and cell cycle. We have observed that 2–4 mM concentrations of AlCl₃ have decreased the number of cells that undergo mitogenesis (PHA-induced blast transformation) and mitosis in human short term whole blood cultures. We have also shown that the rate of the cell cycle was slowed down, i.e., cell cycle time was increased in the presence of AlCl₃. Also, we have demonstrated a reversible effect on aluminum-induced reduced mitotic index in long-term EBV-transformed lymphoblastoid cultures. Although safeguards such as limiting aluminum serum concentrations have been recommended to protect individuals undergoing dialysis, it should be realized that concentration accumulations of aluminum may increase over chronic exposures. Accordingly, if the number of cells stimulated by PHA is reduced in the presence of AlCl₃, there may be a reduction of immune competence, since the degree of PHA stimulation has been used as an indicator of immune response. Similar reductions in mitotic index could affect every tissue involved with cell division. Although it may not be the same for higher concentrations, from our results, we have also shown that decreased mitotic rates were reversible in long-term EBV-transformed lymphoblastoid cultures. Increased numbers of mitoses were observed in human short-term whole blood cultures that were exposed to 2 μM concentrations of aluminum chloride. The concentration is close to those found in normal human serum and within the “safeguard” range recommended for dialysis patients. A similar trend for aluminum sulfate was also observed, while preliminary results for three other aluminum species, lactate, citrate, and maltol, were also reported. Although previous reports have indicated a positive effect of aluminum on mitosis in vitro or in vivo, this is the first such report involving human material. It is clear that higher concentrations of aluminum chloride at 2.0–4.0 mM reversibly inhibit mitosis while more dilute concentrations of 1–2 μM, closer to those found in normal serum, enhance mitosis. The present results, as well as those in the literature, suggest that aluminum may be an essential element in cellular processes for optimal growth, development, and health maintenance. Future research will further test this hypothesis.     

The His-His sequence of the antimicrobial peptide demegen P-113 makes it very attractive ligand for Cu2+

Histatins are a family of histidine-rich, cationic peptides up to 38 amino acids long. As other antimicrobial peptides histatins exhibit in vitro activity against both bacteria and yeasts. A 12 amino acid amidated fragment of histatin 5, designated P-113 or demegen, has been identified as the smallest fragment retaining antimicrobial activity comparable to the parent compound. Demegen, AKRHHGYKRKFH, has three His and a N-terminal group known to participate in copper ion coordination. In this study potentiometric and spectroscopic (UV-vis, CD, EPR, NMR) measurements were used to evaluate the stability constants, stoichiometry and structures of Cu(2+) complexes with demegen P-113 and its analogues in aqueous solution. The main aim of this work was to understand the role of two adjacent histidine residues in metal ion binding. The comparison with results for modified ligands showed that two histydyl residues are basic for complex formation in the 4.5-7 pH range.     

Physical and sensory characteristics of the fruits of eight cultivars of field grown tomato

Evaluation of fruit quality of 8 cvs. of field grown tomatoes were carried out in 1998 and 1999. Physical characteristics: color, firmness, breaking strength and sensory attributes of fruits were determined. Highly significant correlation coefficients existing between instrumental and sensory quality determinations proved their value to be accepted by consumers.     

Liposomal packaging generates Wnt protein with in vivo biological activity

Wnt signals exercise strong cell-biological and regenerative effects of considerable therapeutic value. There are, however, no specific Wnt agonists and no method for in vivo delivery of purified Wnt proteins. Wnts contain lipid adducts that are required for activity and we exploited this lipophilicity by packaging purified Wnt3a protein into lipid vesicles. Rather than being encapsulated, Wnts are tethered to the liposomal surface, where they enhance and sustain Wnt signaling in vitro. Molecules that effectively antagonize soluble Wnt3a protein but are ineffective against the Wnt3a signal presented by a cell in a paracrine or autocrine manner are also unable to block liposomal Wnt3a activity, suggesting that liposomal packaging mimics the biological state of active Wnts. When delivered subcutaneously, Wnt3a liposomes induce hair follicle neogenesis, demonstrating their robust biological activity in a regenerative context.     

Searching for biomarkers of Aurora-A kinase activity: identification of in vitro substrates through a modified KESTREL approach

Aurora-A, -B, and -C are members of a small family of mitotic serine/threonine kinases that regulate centrosome maturation, chromosome segregation, and cytokinesis. They are often overexpressed in different human tumor types and have been identified as attractive targets for anticancer drug development. As specific inhibitors of the Aurora kinases are entering phase I clinical trials, there is a high need for appropriate Aurora-A biomarkers to follow mechanism of action or response. To identify novel Aurora-A substrates potentially useful as specific biomarkers we applied several modifications to the original KESTREL (Kinase Substrate Tracking and Elucidation) method in conjunction with gel electrophoresis and MALDI-MS and LC-MS/MS. The major modifications to the method included the introduction of a heating step to inactivate endogenous kinases after cell lysis and the execution of the in vitro kinase reaction in the presence of 5 mM Mg(2+) and at high (1 mM) ATP concentration. Total and fractionated extracts from nocodazole-treated HeLa cells were used as a source of Aurora-A substrates. Using this approach, we were able to detect a number of Aurora-A specific phospholabeled signals and to identify vimentin as a putative Aurora-A substrate. Vimentin was then confirmed as an in vitro substrate of Aurora-A by the phosphorylation of the recombinant protein followed by MS and antibody detection.     

Further structural analysis of GnRH complexes with metal ions

MALDI-TOF mass spectrometry, 1H NMR spectrometry, the continuous variation method and molecular modeling by MM3 calculation confirmed our earlier studies showing that gonadotropin-releasing hormone (GnRH) forms complex with copper(II) ion with the binding ratio 1:1. The copper(II) complex formed at physiological pH has a square planar configuration and GnRH complexes with nickel(II) and cobalt(II) ions are less stable than that of copper(II).     

The occurrence of wildcat in the Polish Carpathian Mountains

The contemporary occurrence of wildcatFelis silvestris (Schreber, 1775) in the Polish part of the Carpathian Mountains was evaluated in 1998–2000 with personal inquiries in all forest inspectorates of Krosno and Kraków Regional Directorates of State Forests and five national parks (NP). Additional information on the presence of wildcat was collected by snow tracking in three winter seasons: 1998/1999 through 2000/2001. Wildcat presence was confirmed only for Bieszczady Mountains, Pogórze Przemyskie, and Beskid Niski Mountains (13 forest inspectorates and 2 national parks: Bieszczady NP and Magurski NP).     

A study on the nickel II-famotidine complexes

Potentiometric studies have shown that Ni(II) forms three pH-dependent complexes with famotidine (L), namely: [NiHL](3+), [NiL](2+) and [NiH(-2)L]. Two of them have been isolated from solution with a Ni/famotidine ratio of 1:1. At pH 6.0, a paramagnetic complex [NiL](2+) with octahedral geometry is formed in which, most likely thiazole N(9) and guanidine N(3) nitrogens are involved in the metal binding. Additionally, two water molecules and two perchlorate anions, ClO(4)(-), fulfil the coordination sphere. The second complex, [NiH(-2)L], that precipitates at pH 8 is diamagnetic and takes square-planar geometry in which four nitrogen donors: N(3), N(9), N(16) and N(20) coordinate to Ni(II). Potentiometric studies, mass spectrometry, FT-IR and Raman spectroscopy are employed to determine and discuss the structure of both complexes. Additionally, 1H, 13C and 15N NMR spectroscopy is used to confirm the binding site in a square-planar complex. The assignment of vibrational bands are made using ab initio HF/CEP-31G method.